JP2005104191A - Outboard motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To further reduce an exhaust sound in an outboard motor for exhausting exhaust gas under water. <P>SOLUTION: An exhaust passage 18 is formed in a lower casing 13. An exhaust port 18a of the exhaust passage 18 is formed under a propeller 3. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an outboard motor that discharges exhaust gas into water.

  As this type of conventional outboard motor, there is one disclosed in Patent Document 1, for example. The outboard motor shown in Patent Document 1 includes a clamp bracket that is detachably attached to the hull, and a propulsion device that is supported on the clamp bracket via a swivel bracket so as to be steerable. The propulsion device includes an upper casing supported by the clamp bracket via the swivel bracket, an engine mounted on an upper end portion of the upper casing, a lower casing attached to a lower end portion of the upper casing, and the lower casing. The propeller is rotatably supported by the casing, and a transmission device that transmits the power of the engine to the propeller.

  The upper casing is formed long in the vertical direction so that the lower end of the upper casing is submerged below the water surface when the outboard motor is in use, and an exhaust passage is formed inside. An upper end portion of the exhaust passage is communicated with an exhaust port of the engine, and a lower end portion is communicated with an exhaust port formed at a rear end portion of the lower casing. The discharge port is formed so as to be located below the water surface and above the rear portion of the propeller. That is, in this outboard motor, the exhaust gas is discharged from the discharge port into the water above the rear part of the propeller.

In addition, the applicant could not find any prior art documents closely related to the present invention by the time of filing other than the prior art documents specified by the prior art document information described in the present specification. .
Japanese Patent Publication No. 2-18403

  In the conventional outboard motor configured as described above, since the exhaust gas is discharged into the water, the exhaust noise can be reduced as compared with the case where the exhaust gas is discharged from the upper casing into the atmosphere. However, it is required to further reduce the exhaust noise.

  The present invention has been made to solve such problems, and it is an object of the present invention to further reduce exhaust noise in an outboard motor that discharges exhaust gas into water.

In the outboard motor according to the present invention, an exhaust port through which engine exhaust gas is discharged is formed below the propeller.
The outboard motor according to the invention described in claim 2 is the outboard motor according to the invention described in claim 1, wherein the discharge port is formed behind the propeller.

  The outboard motor according to the invention described in claim 3 is the outboard motor according to the invention described in claim 1 or 2, wherein the exhaust passage for guiding the exhaust gas to the discharge port is provided inside the outboard motor casing. The exhaust passage and the gear coupling portion are defined by an inner wall of the exhaust passage. The exhaust passage and the gear coupling portion are formed so as to pass through the front and lower sides of the gear coupling portion between the drive shaft for driving the propeller and the propeller shaft.

  The exhaust gas flow discharged from the underwater discharge port is bubbled in the water, the bubbles rise in the water and reach the water surface, and the exhaust gas diffuses into the atmosphere. The exhaust sound emitted from the underwater outlet together with the exhaust gas flow is partially transmitted to the water from the surface of the exhaust gas flow or the bubble surface made of exhaust gas, propagates through the water and is transmitted to the atmosphere at the water surface, It propagates in the atmosphere from near the water surface to the eardrum of the person on the hull, and is detected as noise by the person on the hull. The remainder of the exhaust sound emitted from the water outlet along with the exhaust gas flow is confined in the bubbles (as a dense wave of exhaust gas molecules reflected by the surrounding water walls in the bubbles), and the bubbles are on the water surface. Upon reaching and escaping, the exhaust sound propagates directly to the atmosphere, and further propagates through the atmosphere and is perceived as noise by people on the hull. The transmission of acoustic energy from gas to water and from water to the atmosphere is poor, and it is easy to diffuse widely in water, and the ratio at the surface of the water near the hull is extremely small. The acoustic energy is extremely small. For this reason, the sound exhausted from the water outlet is perceived by humans as exhaust noise, and the acoustic energy confined in the bubbles bursts into the atmosphere and reaches the people. Most of the things.

  According to the present invention, since the exhaust gas is discharged into the water from the deepest part of the outboard motor that is submerged in water, the time required until the exhaust gas that has been discharged from the discharge port and bubbled rises is relatively long. Thus, since the distance that the hull moves forward becomes longer before the bubbles rise, it becomes difficult to hear the sound generated when the bubbles made of exhaust gas rise on the water surface.

  According to the second aspect of the present invention, since the bubbles made of the exhaust gas discharged from the discharge port ascends behind the propeller, the bubbles are pushed by the water flow generated by the propeller and flowed backward. The sound generated by ascending becomes more difficult to hear from the ship. Further, the bubbles are vigorously stirred by the water flow generated by the propeller, and are finely crushed. At this time, the contact boundary between the water and the exhaust gas changes drastically, whereby the dense wave of the exhaust gas is attenuated and the exhaust noise is reduced. Further, when the bubbles are crushed finely, the rising resistance due to water increases, so that they are carried farther from the hull and reach the water surface, and the exhaust noise is reliably reduced.

  According to the third aspect of the present invention, the wall of the exhaust passage formed at the front and lower sides of the gear coupling portion between the drive shaft and the propeller shaft substantially functions as a protective member, and the gear coupling portion is disposed at the front and lower portions. Can be protected from. For this reason, the outboard motor according to the present invention can continue to travel even if the lower end collides with a foreign object such as a riverbed, a seabed, a pile, or a driftwood, and the gear coupling portion is not damaged. .

Hereinafter, an embodiment of an outboard motor according to the present invention will be described in detail with reference to FIGS.
1 is a side view of an outboard motor according to the present invention, FIG. 2 is a plan view of the same, FIG. 3 is a cross-sectional view of the upper upper casing, FIG. 4 is a cross-sectional view of the upper upper casing in FIG. Is a sectional view of the lower part of the upper casing and the lower casing, FIG. 6 is a sectional view taken along line VI-VI in FIG. 5, FIG. 7 is a sectional view taken along line VII-VII in FIG. is there.
9 is a cross-sectional view of the swivel bracket, FIG. 10 is a cross-sectional view taken along line XX in FIG. 9, FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. FIG. 13 is a sectional view showing the swivel bracket rotated with respect to the clamp bracket, FIG. 14 is a sectional view taken along the line XIV-XIV in FIG. 9, and FIG. 15 is a sectional view taken along the line XV-XV in FIG. FIG. FIGS. 16 to 18 are cross-sectional views for explaining the operation of the thrust bracket, and FIG. 19 is a cross-sectional view showing a state when an impact is applied to the propulsion device during traveling. 20 is a plan view for explaining the position for mounting the outboard motor according to the present invention, FIG. 21 is a cross-sectional view corresponding to a cross section taken along line XI-XI for showing another embodiment of the swivel bracket, and FIG. 22 is a stern. It is a top view which shows the form which attached the outboard motor to the board.

In these drawings, what is indicated by reference numeral 1 is an outboard motor according to the present invention. The outboard motor 1 includes a propulsion device 4 configured to drive a propeller 3 by an engine 2 and an attachment member 6 for attaching the propulsion device 4 to a hull 5.
The propulsion device 4 includes an upper casing 11 supported by a mounting member 6 to be described later, the engine 2 mounted on the upper casing 11, a cowling 12 covering the engine 2, and a lower end of the upper casing 11. The lower casing 13 is attached to the section, and the propeller 3 is rotatably supported by the lower casing 13.

  The upper casing 11 is formed by casting an aluminum alloy as a material. As shown in FIGS. 3 to 5, the upper casing 11 has an upper end portion 14 that supports the engine 2 and a cylindrical shape that extends downward from the upper end portion 14. The shaft portion 15 and a flat portion 16 extending downward from the lower end of the shaft portion 15 are integrally formed. As shown in FIGS. 7 and 8, the flat portion 16 has a width at the center portion in the front-rear direction that is wider than both end portions, and the front end portion and the rear end portion are gradually narrower toward the front end side. It is formed to become.

  That is, it is possible to adopt a shape that is symmetrical in the front-rear direction, a streamlined shape in which the central portion is forward, or a portion in which the central portion is rearward. In this embodiment, the portion of the drive shaft 20 to be described later is a wide central portion, and the drive shaft 20 is disposed rearward. Thereby, while being able to form the hollow part 17 of sufficient cross-sectional area inside the upper casing 11, the water resistance of the part submerged at the time of sailing can be made small. The portion in the vicinity of the water surface in the flat portion 16 is formed so that the cross-sectional shape is substantially the same from above the water surface to below the water surface. The position of the water surface is indicated by a two-dot chain line W in FIG. That is, the flat part 16 extends from the upper surface of the splash plate or the upper casing to the upper side of the rear propeller, as provided in a conventional outboard motor, and air is caught in the propeller 3 from the water surface. No so-called cavitation plate is formed.

  The hollow portion 17 functions as a muffler. More specifically, the hollow portion 17 has an upper end portion closed by the engine 2 attached to the upper end portion of the upper casing 11, and the lower casing 13 is connected to the lower end portion, whereby the exhaust passage 18 of the lower casing 13. It is communicated to. The engine 2 is formed such that an exhaust port 2 a (see FIGS. 3 and 9) opens into the hollow portion 17. The exhaust passage 18 of the lower casing 13 is formed inside the protector 19 projecting below the propeller 3 so as to extend rearward after passing through the front side of the outboard motor. It is open toward. The protector 19 according to this embodiment is integrally formed with a pipe 19 a protruding rearward at a rear end portion, and the pipe 19 a is configured to be a downstream end of the exhaust passage 18. The pipe 19a is formed so as to be substantially parallel to the axis of the propeller 3 as shown in FIGS. 1 and 5, and in the traveling state shown in FIG. 1 (a state where the tilt angle is maximized). An opening at the rear end is formed so as to be located behind the propeller. An exhaust port 18a of the exhaust passage 18 is formed by the opening at the rear end of the pipe 19a.

  In the hollow portion 17, cooling water is supplied to the engine from a drive shaft 20 for transmitting the power of the engine 2 to the propeller 3 and a cooling water pump 21 (see FIGS. 5 and 6) in the lower casing 13. The cooling water pipe 22 for leading to 2 is provided so as to penetrate in the vertical direction. The drive shaft 20 has an upper end connected to a crankshaft (not shown) of the engine 2 and a lower end supported rotatably on the upper casing 11 and the lower casing 13 by bearings 23 and 24 (see FIG. 5). ing. The bearing 23 is attached to a partition wall 25 interposed between the upper casing 11 and the lower casing 13. This partition wall 25 is for watertightly forming an oil chamber 13b (see FIG. 5) in which a bevel gear 37 described below is accommodated.

  The engine 2 is a water-cooled four-cycle single-cylinder engine and is mounted on the upper end portion 14 of the upper casing 11 in a state where an axis of a crankshaft (not shown) is directed in the vertical direction. In the engine 2 according to this embodiment, as shown in FIGS. 3 and 4, an oil pan 2b provided at the lower end portion is placed on the upper end portion 14, and at this time, the lower end portion of the crankshaft is the drive shaft. Connected to the shaft 20. The exhaust port 2a is formed in the oil pan 2b. The cooling water from the cooling water pump 21 is sent from the cooling water pipe 22 to an oil pan 2b of the engine 2 and a cooling water jacket (not shown) around the exhaust port 2, and a cooling water jacket of a cylinder and a cylinder head. After each part is cooled by the water jacket, it is discharged to the outside from a cooling water discharge port (not shown).

  Further, as shown in FIG. 1, the engine 2 is covered with a cowling 12 while being mounted on an upper casing 11. As is well known in the art, the cowling 12 includes a bottom cowl 12a fixed to the upper end 14 and an upper cowl 12b detachably attached to the upper end of the bottom cowl 12a. Yes.

  The bottom cowl 12a is provided with a carrying handle 26 at the rear end and a steering handle 27 at the front end. As shown in FIG. 2, the steering handle 27 is positioned at the center in the left-right direction of the outboard motor 11. Further, as shown in FIG. 1, the steering handle 27 is attached to a bracket 12c on the bottom cowl 12a side so as to be swingable in the vertical direction via a support shaft 28. The steering state (propulsion) shown in FIG. The apparatus 4 is configured to be able to extend forward substantially horizontally in a state where the apparatus 4 is inclined with respect to the vertical direction. A throttle grip 27 a is provided at the tip of the steering handle 27.

A cushion rubber 29 is attached to the lower surface of the bracket 12c. The cushion rubber 29 abuts against a mounting member 6 described later when the inclination angle of the propulsion device 4 further increases from the sailing state, and restricts the inclination angle of the propulsion device 4 from increasing more than necessary. This is to alleviate the impact when the lower casing 13 collides with the driftwood.
As shown in FIGS. 1 and 2, the upper cowl 12 b is provided with a starter handle 30 and a choke knob 31 at the front end. In FIG. 1 and FIG. 2, what is shown by the code | symbol 32 located in the upper end part of the upper cowl 12b is a cap for fuel tanks.

The lower casing 13 is formed by casting an aluminum alloy as a material in the same manner as the upper casing 11. The lower casing 13 according to this embodiment is formed in a shape that extends the flat portion 16 of the upper casing 11 downward, that is, a streamline shape or a shape with little resistance near it, and has a plate shape at the lower end. A protector 19 is provided so as to protrude downward.
Further, as shown in FIG. 5, the lower casing 13 is provided with a propeller 3 rotatably provided at an upper end and an end on the rear side (left side in the figure) of the outboard motor. A cooling water pump 21 is provided at the center in the vertical direction. That is, the cooling water pump 21 is disposed below the water surface indicated by a two-dot chain line W in FIG.

  The propeller 3 is detachably attached to the propeller shaft 34. The propeller shaft 34 is rotatably supported by a cylindrical bearing member 35 fixed to the boss 13 a of the lower casing 13 by a bearing 36, and an inner end portion is connected to the drive shaft 20 via a bevel gear 37. That is, as shown in FIG. 5, the propeller shaft 34 is inclined so as to gradually become lower toward the rear in a state where the drive shaft 20 extends in the vertical direction.

  The bevel gear 37 and the gear coupling portion where the propeller driving member such as the lower end portion of the drive shaft 20 and the bearing 24 is located are arranged at the upper portion in the center portion of the lower casing 13 in the front-rear direction. That is, in the lower casing 13 according to this embodiment, as shown in FIG. 5, the exhaust passage 18 is formed so as to pass through the front and the lower side of the gear coupling portion, and the gear coupling portion and the exhaust passage 18 are formed. Are defined by the exhaust passage inner wall 18b.

  The cooling water pump 21 is a centrifugal pump, and is connected to the lower end of the drive shaft 20 as shown in FIGS. Specifically, the rotor 21 a of the cooling water pump 21 is fixed to the lower end surface of the drive shaft 20 so as to be positioned on the same axis as the drive shaft 20. In the rotor 21a according to this embodiment, the two gears of the bevel gear 37 and the bearings 24 provided in the lower casing 13 are prevented so that the rotor 21a does not increase the thickness of the lower casing 13 in the left-right direction. , 36 so that the outer diameter is smaller.

  As shown in FIG. 6, the housing 21 b that houses the rotor 21 a is formed so that both end portions in the left-right direction are along the side surface of the lower casing 13, and is fixed to the lower casing 13. The housing 21b is formed with a cooling water inlet 38 (see FIG. 1) at a portion that becomes the side surface of the lower casing 13, and a cooling water discharge port 39 (see FIG. 5) is formed at the upper end portion on the rear side of the outboard motor. Has been. The cooling water discharge port 39 is connected to the cooling water pipe 22 via a cooling water passage 40 formed in the lower casing 13. In FIG. 5, 23a and 24a are oil seals that seal the outer periphery of the drive shaft 20, 36a is an oil seal that axially seals the outer periphery of the propeller shaft 34, and 25a is a water-tight seal between the lower casing 13 and the partition wall 25. The gasket is for preventing external water from entering the lubricating oil in the oil chamber 13b. The lower casing 13 is provided with a lubricating oil inlet and outlet (not shown), and a removable stopper is attached. In addition, a part of the lower casing 13 and the front portion of the cooling water intake 38 in the housing 21b disposition portion are recessed from the outer surface of the upper and lower lower casings 13 so that the dynamic pressure from the front acts on the cooling water intake 38. It may be.

  In the cooling water pump 21 according to this embodiment, the rotor 21a rotates simultaneously with the rotation of the drive shaft 20 when the engine is started, and sucks outside water from the cooling water intake port 38 and discharges it from the cooling water discharge port 39. Therefore, the cooling water is discharged from the cooling water pump 21 to the cooling water pipe 22 and supplied to the engine 2 substantially in synchronization with the start of rotation of the drive shaft 20. The cooling water intake 38 is provided in the housing 21b of the cooling water pump 21, and it is not necessary to form a suction passage in the lower casing 13, so that the cost can be reduced. Furthermore, a plurality of cooling water intakes 38 are provided to prevent clogging by algae, and the cooling water intakes 38 are arranged on the surface of the lower casing 13 at a position below or above the cooling water pump 21 and below the water surface. You may make it guide to the cooling water pump 21 by a suction passage.

As shown in FIG. 1, the attachment member 6 includes a clamp bracket 41 attached to the slat 5 a of the hull 5, and a swivel bracket 42 for attaching the propulsion device 4 to the outer end of the clamp bracket 41. It is composed of The hull 5 on which the outboard motor 1 according to this embodiment is mounted is of a so-called double-ender type in which both the bow and stern are pointed, the hull resistance is low during medium / low speed driving, and it is difficult to cause a pulling wave. is there.
As shown in FIGS. 9 to 11 and 16, the clamp bracket 41 includes a front clamp 43 and a rear clamp 44 that are fixed to the slat 5 a by sandwiching the slat 5 a on the starboard side of the hull 5. The upper and lower rods 45 (see FIG. 10) and the lower rod 46 (see FIG. 1) connect the clamps 43 and 44 to each other in a state where the front and rear clamps 43 and 44 are separated from each other in the longitudinal direction of the hull 5. The mounting plate 49 is interposed between the upper ends of the clamps 43 and 44 and is attached to the clamps 43 and 44 by an upper mounting bolt 47 and a lower mounting bolt 48. Yes. Each of the clamp 43 and the clamp 44 is provided with a pressing pad 41a for sandwiching the flange plate 5a, a pressing screw 41b to be screwed to the clamps 43 and 44, and a pressing handle 41c for rotating the pressing screw 41b. It has been. Note that the clamps 43 and 44 are front and rear when the clamp bracket 41 is fixed to the port side 5b as shown in FIG.

As shown in FIG. 10, the mounting plate 49 is formed to have an arc shape in which a central portion in the front-rear direction (left-right direction in FIG. 10) is convex toward the inside of the hull in plan view. A swivel bracket 42 to be described later is fixed by two fixing bolts 50 on the outer side away from the hull in the curved portion.
The two mounting bolts 47 and 48 for fixing the mounting plate 49 to the front clamp 43 pass through the clamp 43 substantially horizontally from the front side of the hull to the mounting plate 49 while being spaced apart from each other in the vertical direction. The two mounting bolts 47 and 48 that are screwed and fix the mounting plate 49 to the rear clamp 44 pass through the clamp 44 substantially horizontally from the rear side of the hull while being spaced apart from each other in the vertical direction. Screwed to the mounting plate 49.

  As shown in FIGS. 11 to 13, the front and rear screw holes 47a and 47a into which the front and rear mounting bolts 47 and 47 are screw-fitted are formed coaxially with each other on the mounting plate 49, and the front and rear mounting bolts 48 and 47, respectively. Similarly, the screw holes 48a and 48a before and after the 48 are screwed are formed coaxially with the mounting plate 49, respectively. The screw through holes 47b and 47b of both clamps 43 and 44 through which the upper mounting bolt 47 passes are formed in perfect circles, and the screw through holes 48b and 48b of the front and rear clamps 43 and 44 through which the lower mounting bolt 48 is inserted. 16 is formed by a long hole along a virtual arc centered on the upper mounting bolt 47, as shown in FIG. For this reason, the mounting plate 49 can swing the lower end portion in the left-right direction of the hull 5 around the upper mounting bolt 47 when the four mounting bolts 47, 48 are loosened. The angle with respect to the plate 5a can be adjusted by an angle corresponding to the length of the long hole 48a.

  As shown in FIG. 11, the swivel bracket 42 includes a swivel bracket body 51 attached to the attachment plate 49 by two fixing bolts 50, and a tilt shaft 52 (see FIG. 10) that is horizontal to the swivel bracket body 51. And a plurality of parts of a pivot bracket 53 supported so as to be pivotable in the vertical direction. Note that the tilt shaft 52 rotates in the vertical direction around the tilt axis without the interference of the propulsion device 4 with the hull 5 between 0 ° (parallel to the horizontal plane) and about 30 ° with respect to the horizontal plane. You may attach to the bracket main body 51 inclining so that it may become arbitrary angles (for example, 5 degrees, 10 degrees, 15 degrees, 20 degrees, 25 degrees etc. or these intermediate angles) which can move. As a result, the propulsion device 4 can be surely scattered outside the ship even if the pivot bracket is damaged due to a driftwood collision or the like when the trajectory at the time of jumping is kept away from the hull (see FIG. 10). 10) or by moving the trajectory at the time of jumping up close to the hull, making it easy to replace the propeller from the inside of the hull (the end of the tilt shaft 52 inside the hull in FIG. 10). To lower the water surface).

The swivel bracket body 51 includes a support block 54 formed to have a C-shaped cross section, and a tilt shaft support that protrudes upward from both ends in the left-right direction at the upper end of the support block 54. Boss 55 (see FIGS. 1 and 10) and a stopper 56 (see FIGS. 15 and 16) which is the lower end of the support block 54 and extends downward from both ends in the left-right direction. In this embodiment, the swivel bracket main body 51 is integrally formed with the support block 54, the tilt shaft support boss 55 and the stopper 56 by casting an aluminum alloy as a material.
As shown in FIG. 10, the tilt shaft 52 is horizontally mounted and fixed to the boss 55 for supporting the tilt shaft. In this embodiment, a large-diameter hole 55 a into which the tilt shaft 52 is fitted to both bosses 55, a small-diameter hole 55 b serving as a tool hole for extracting the tilt shaft 52 into one boss 55, and the other boss 55 A female screw at the mouth of the large diameter hole 55a is formed, and a plug 55c for preventing the tilt shaft 52 from coming off is attached.

As shown in FIG. 11, the support block 54 is formed so that the outer peripheral portion has a curvature that fits the outer portion of the mounting plate 49, and the two fixing bolts 50 are screwed to the outer peripheral portion. A plurality of screw holes 57 to be attached are formed at intervals in the circumferential direction.
As shown in FIG. 16, the fitting portion between the support block 54 and the mounting plate 49 has a convex portion 54 a formed at the center in the vertical direction of the support block 54, and a concave portion 49 a of the mounting plate 49. By fitting the two members, the movement in the vertical direction with respect to the other of the two members is restricted.

  The plurality of screw holes 57 formed in the support block 54 are used for support so that the support block 54 can be rotated in the horizontal direction with respect to the mounting plate 49 to change its mounting angle. The blocks 54 are formed in a state of being arranged at predetermined intervals in the circumferential direction. Since the support block 54 is a member that supports the propulsion device 4 via the tilt shaft 52 and a pivot bracket 53 described later, the mounting angle of the support block 54 to the mounting plate 49 is set as described above. By changing the angle, the angle (position) of the propulsion device 4 with respect to the clamp bracket 41 can be changed.

  For example, as shown by a solid line in FIG. 20, when the clamp bracket 41 is attached to the center portion in the front-rear direction of the hull plate 5a on the right side of the hull, as shown in FIGS. The left side surface of the stopper 56 is fixed to the mounting plate 49 when viewed from the stopper 56 side in a state where a rearward extending portion 56b of a lower end portion of the stopper 56 described later extends toward the rear of the hull. Hereinafter, the mounting position of the support block 54 is referred to as a right mounting position. In this right-side mounting position, the imaginary line L extending in the front-rear direction along the rib 5a and the axis of the tilt shaft 52 are substantially orthogonal in the plan view shown in FIG.

  In addition, as shown in FIG. 20A, when the clamp bracket 41 is attached to the center portion in the front-rear direction of the left side hull 5b, as shown in FIG. The right side surface is fixed to the mounting plate 49 when viewed from the rear of the hull with the rearward extending portion 56b of the lower end portion 56 extending toward the rear of the hull. Hereinafter, the mounting position of the support block 54 is referred to as a left side mounting position. In this left-side mounting position, the opposite side in the left-right direction is fixed to the right-side mounting position on the mounting plate 49. In this state, the imaginary line L extending in the front-rear direction along the flange plate 5b and the tilt shaft 52 The axis is almost perpendicular to the axis.

  Further, as shown in FIG. 20B, when the clamp bracket 41 is attached to the rear side of the hull plate 5a on the right side of the hull, as shown in FIG. The left end is fixed to the mounting plate 49 while being rotated counterclockwise. This attachment position is hereinafter referred to as an intermediate position. In this intermediate position, even if it is attached to a part that is inclined in a plan view with respect to the front-rear direction of the hull 5, the tilt shaft 52 with respect to the virtual line L extending in the front-rear direction along the saddle plate 5a The axis lines of

  In this embodiment, as shown by (C) in FIG. 20, a clamp bracket 41 is attached to the rear part of the hull plate 5b on the left side of the hull, or on the right side of the hull as shown in (B) in FIG. A plurality of screw holes 57 are formed in the support block 54 so that the clamp bracket 41 can be attached to the rear portion of the flange plate 5a. These screw holes 57 are arranged so that the support block 54 can be positioned at seven intermediate positions between the right side mounting position and the left side mounting position. In FIG. 11, the support block 54 can be fixed to the mounting plate 49 in a state where the stopper 56 extends in a direction perpendicular to the anchor plate 5a and outward of the hull. In this state, as shown in FIG. 22, the clamp bracket 41 can be attached to the stern plate 5c which is arranged in the left-right direction of the hull at the stern as in the conventional outboard motor. In the present embodiment, the degree of freedom of the attachment position of the outboard motor 1 to the hull 5 can be increased.

  In the embodiment shown in FIG. 21, the through hole 49a of the fixing bolt 50 of the mounting plate 49 is perpendicular to the cylindrical center line of the outer peripheral surface of the cylindrical support block 54 (= horizontal direction). It has a long hole. What is indicated by reference numeral 50a through which the fixing bolt 50 passes is a washer. From the state shown in FIG. 21, the fixing bolt 50 is loosened, and the fixing bolt 50 is tightened at a position where the supporting block 54 is turned by a predetermined angle in the right direction when viewed from above. In a state where 54 is fixed, the clamp bracket 41 can be attached to the front portion of the hull plate 5a on the right side of the hull. This is illustrated as (D) in FIG. Similarly, the fixing bolt 50 passes through the long through hole 49a and is attached to the screw hole 57 on the lower side in FIG. 21, and the fixing bolt 50 is turned counterclockwise from the center of the long hole of the through hole 49a. The clamp bracket 41 can be attached to the front portion of the hull plate 5a on the right side of the hull with the support block 54 fixed to the attachment plate 49 so as to be positioned on the other side. This is illustrated as (E) in FIG.

  In the embodiment shown in FIG. 21, by making the through hole 49a an elongated hole, the angle range in which the support block 54 can be attached to the attachment plate 49 is set to be larger than the angle formed by the screw holes 50 at both ends in the turning direction. Can be increased. Further, the adjustability of the mounting angle of the support block 54 with respect to the mounting plate 49 can be increased. Furthermore, by increasing the angle range that the fixing bolt 50 can take in the elongated hole than the angle formed by the adjacent screw holes 50, the mounting plate 49 can be mounted at an arbitrary relative angle within the mountable angle range of 180 ° or more. The support block 54 can be fixed to the hull 5, and the degree of freedom of the mounting position of the outboard motor 1 on the hull 5 can be further increased.

  As another example of the positional relationship between the rotation center P1 of the upper casing 11 and the rotation center P2 of the swivel bracket 42, the rotation center P1 of the upper casing 11 coincides with the rotation center P2 of the swivel bracket 42. Alternatively, the propeller 3 may be displaced forwardly. As a result, the tilt shaft 52 positioned in front of the rotation center P1 so as not to interfere with the upper casing 11 is positioned further forward as shown in FIGS. 9 and 10, so that the swivel bracket 42 is rotated. When the propulsion device 4 is tilted up with the tilt shaft 52 intersecting the saddle plate 5a, the portion of the engine 2 approaches the hull 5 and the maintenance and inspection performance of the engine 2 is improved. In order to improve the maintenance and inspection performance of the engine 2, the tilt shaft 52 may be positioned above the upper end of the roof plate 5a in the vertical direction. Thereby, the interference to the upper side of the saddle plate 5a of the propulsion device 4 at the time of tilt up can be avoided.

The stopper 56 constitutes a part of a thrust stopper 58, which will be described later. As shown in FIG. 1, as shown in FIG. 1, a vertically extending portion 56 a extending downward from both left and right ends of the support block 54, and It is formed by the back extension part 56b extended back from the lower end of this up-down direction extension part 56a.
The rear extending portion 56b is formed to have an arc shape with the tilt shaft 52 as a center, and as shown in FIG. An engagement groove 60 into which the pin 59 is engaged is formed. As shown in FIG. 16, the engagement groove 60 includes a communication portion 60a extending along an arc centered on the tilt shaft 52, and an engagement portion 60b extending outward from the communication portion 60a in the radial direction of the arc. It is constituted by. A plurality of the engaging portions 60b are formed at intervals in the direction along the arc.

  As shown in FIG. 10, the pivot bracket 53 is inserted between the two bosses 55 for supporting the tilt shaft, and is supported by the tilt shaft 52 so as to be rotatable in the vertical direction. 53a, and a second pivot bracket 53b fixed to the rotating end (rear end) of the first pivot bracket 53a by a fixing bolt 61. These first and second pivot brackets 53a and 53b rotatably support the shaft portion 15 of the upper casing 11. That is, the pivot bracket 53 is supported by the tilt shaft 52 so as to be rotatable in the vertical direction, and also supports the upper casing 11 so as to be rotatable in the horizontal direction.

  The pivot center P1 of the upper casing 11 that is pivotally supported by the pivot bracket 53 is a part where the drive shaft 20 is located in FIG. 10, and the pivot center of the swivel bracket 42 having the pivot bracket 53. It is positioned at a position away from P2. As shown in FIGS. 10 and 11, when the support block 54 is located at the right mounting position, the pivot center P1 of the upper casing 11 is located on the rear side of the hull from the pivot center P2 of the swivel bracket 42. When the support block 54 is positioned at an intermediate position as shown in FIG. 13, the rotation center P <b> 1 of the upper casing 11 is positioned outside the hull from the rotation center P <b> 2 of the swivel bracket 42. .

As shown in FIG. 10, a belt-like friction plate 62 is interposed at a portion of the pivot bracket 53 that rotatably supports the upper casing 11. The friction plate 62 can increase or decrease the sliding resistance when the upper casing 11 rotates with respect to the pivot bracket 53 by tightening or loosening the thumbscrew denoted by reference numeral 63 in FIG. Is formed.
As shown in FIGS. 9 and 15, an upper end portion of a thrust stopper 58, which will be described later, is provided at the central portion in the left-right direction (the axial direction of the tilt shaft 52) of the portion through which the tilt shaft 52 penetrates in the first pivot bracket 53a. Is formed so as to open downward.

The thrust stopper 58 is for restricting the tilt angle of the propulsion device 4 and receiving the thrust of the propulsion device 4, and the thrust is a swivel bracket main body 51, a mounting plate 49 and a clamp, part of which is the stopper 56. It is transmitted to the hull 5 through the bracket 41. As shown in FIGS. 9 and 14 to 18, the thrust stopper 58 is supported by a thrust bracket 64 rotatably supported by the tilt shaft 52, and is supported by the thrust bracket 64 so as to be movable in the vertical direction. The pin 59 is configured.
The thrust bracket 64 includes a support stay 65 extending downward from the tilt shaft 52 and a pressure receiving block 66 fixed to the lower end portion of the support stay 65. The support stay 65 is made of a pipe, and as shown in FIGS. 15 to 18, a driving rod 67 to which an engaging pin 59 to be described later is screwed is fitted at the lower end so as to be movable in the vertical direction. .

As shown in FIG. 14, the pressure receiving block 66 includes a plate-shaped pressure receiving portion 66 a having a half cylindrical inner peripheral surface into which the shaft portion 15 of the upper casing 11 is slidably fitted in the circumferential direction. A recessed groove 66b (see FIG. 15) is formed in the rear side of the outboard motor as a thrust receiver and into which the engaging pin 59 is fitted. As shown in FIGS. 15 and 17, the concave groove 66b is formed so as to penetrate the pressure receiving block 66 in the left-right direction, and is open downward.
As shown in FIGS. 14 and 15, the engagement pin 59 is formed to be parallel to the tilt shaft 52 and to be longer than the length of the pressure receiving block 66 in the left-right direction (vertical direction in FIG. 14). It is accommodated in the concave groove 66 b, and both end portions protruding from the pressure receiving block 66 are engaged with the engaging groove 60 of the stopper 56. The position of the engaging pin 59 in the rotating direction is changed by the pressure receiving block 66 rotating around the tilt axis in a state where the engaging pin 59 is positioned in the communication portion 60a of the engaging groove 60, and the plurality of engaging portions It is engaged with one engaging part 60b selected from 60b.

  A driving rod 67 for vertically moving the pin in the concave groove is provided upright at the center of the engaging pin 59 in the longitudinal direction. The drive rod 67 protrudes upward through the pressure receiving block 66 and is inserted into the support stay 65 from below. A compression coil spring 68 for urging the engagement pin 59 downward is provided between the engagement pin 59 and the upper wall of the pressure receiving block 66 in the drive rod 67. Further, an operation wire 69 is connected to a portion of the drive rod 67 that is inserted into the support stay 65. A support bracket 1100 for the inner cable of the operation wire 69 is screwed into the drive rod 67 through a vertical hole opened in the pipe-like support stay 65, and above the support bracket 1100. Thus, the support brackets 2 and 101 for the outer cable of the operation wire 69 are fixed to the support stay 65. The other end of the operation wire 69 is connected to an operation lever 70 attached to the clamp bracket 41 as shown in FIG. The operating lever 70 can be attached to the steering handle 27 as shown in FIG.

  The engaging pin 59 according to this embodiment is urged downward by the elastic force of the compression coil spring 68 in a state where the operating lever 70 is not operated, and both end portions of the engaging groove 60 are Engage with the engaging portion 60b. Thus, when the engaging pin 59 engages with the engaging portion 60b, the position of the pressure receiving block 66 (the position of the upper casing 11 during traveling) is determined, and the rotation of the thrust bracket 64 about the tilt axis is performed. Be regulated. For example, as shown in FIG. 16, the engagement pin 59 is engaged with the engagement portion 60 b located on the most front side of the outboard motor (right side in FIG. 16) among the plurality of engagement portions 60 b formed on the stopper 56. As a result, the rotation of the thrust bracket 64 is restricted in a state where the pressure receiving block 66 is located closest to the outboard motor front side. In this state, as indicated by a two-dot chain line in FIG. 1, the axis C (the axis parallel to the axis of the drive shaft 20) of the upper casing 11 of the propulsion device 4 is directed in the vertical direction.

  In order to change the tilt angle of the propulsion device 4, first, the operation lever 70 is operated to pull the wire 69, and the drive rod 67 and the engagement pin 59 are moved upward. By this operation, both end portions of the engagement pin 59 enter the communication portion 60a from the engagement portion 60b, and the thrust bracket 64 can be rotated around the tilt axis. Next, as shown in FIG. 17, while continuously operating the operation lever 70, the propulsion device 4 and the thrust bracket 64 are rotated around the tilt axis in the clockwise direction in the drawing until the desired tilt angle is reached. (Tilt up) and release the operating lever 70. By releasing the operating lever 70 in the tilted state as described above, the engaging pin 59 is pushed by the elastic force of the compression coil spring 68, and both end portions thereof are engaged with the engaging portion 60b. At this time, for example, when the propulsion device 4 and the thrust bracket 64 are tilted up to a position where the tilt angle becomes maximum, as shown in FIG. 18, the outboard motor is the most out of the plurality of engaging portions 60b formed. The engaging pin 59 is engaged with the engaging portion 60b located on the rear side.

  As shown in FIG. 1, the outboard motor 1 according to this embodiment tilts the propulsion device 4 so that the tilt angle is maximized so that the axis of the propeller 3 is substantially horizontal as shown in FIG. It is configured. When tilting down, the operating lever 70 is operated to release the engagement between the engaging pin 59 and the stopper 56 in the same manner as tilting up, and the propulsion device 4 and the thrust bracket 64 are rotated in this state. It is done by moving. In addition, a torsion spring 103 is provided in which one end is fixed to the support block 54 by a bolt 102 and the other end via the coil portion is in contact with the pressure receiving block 66. Thus, the thrust bracket 64 is biased in the tilt-up direction, and only the propulsion device 4 needs to be tilted up during the tilt-up operation. Further, since the torsion spring 103 is displaced by the weight of the propulsion device 4 at the time of tilting down, it is not necessary to put a hand on the thrust bracket 64. By adopting this configuration, the thrust bracket 64 rotates following the propulsion device 4 at the time of tilt up or tilt down, and it becomes unnecessary to support the thrust bracket 64, thereby improving the operability.

  As shown in FIG. 1, the outboard motor 1 configured as described above includes a maximum trim-up position where the axis of the propeller 3 is substantially horizontal, and a propulsion device as indicated by a two-dot chain line in the drawing. The tilt angle (also referred to as the trim angle between the maximum trim-up position and the tilt-down position) can be changed so as to correspond to the position of the engaging portion 60b between the tilt-down position at which 4 stands. In any tilt position (also between the maximum trim-up position and the tilt-down position, it is also called a trim position), the propeller 3 moves forward by rotating with the power of the engine 2. The forward thrust is transmitted from the upper casing 11 to the swivel bracket body 51 via the clamp bracket 41 and the tilt shaft 52, and from the upper casing 11 to the swivel bracket via the pressure receiving block 66 and the engagement pin 59. It is transmitted to the main body 51, and transmitted from the swivel bracket main body 51 to the hull 5 through the mounting plate 49 and the clamp bracket 41. Steering at the time of sailing is performed by steering the steering handle 27 in the horizontal direction and rotating the propulsion device 4 in the horizontal direction with respect to the pivot bracket 53.

  On the other hand, when the hull 5 mounted with the outboard motor 1 is moved backward, first, the propulsion device 4 is tilted down to a tilt-down position indicated by a two-dot chain line in FIG. Then, in this state, the propulsion device 4 is rotated in the horizontal direction with respect to the pivot bracket 53 so that the steering handle 27 is directed rearward, and the advancing direction is directed rearward. By rotating, the hook 15 a protruding in an arc shape on the upper casing 11 is engaged with an arc-shaped engaging portion 66 c formed integrally with the lower end portion of the pressure receiving block 66. Also in the case of reversing, the thrust of the propulsion device 4 is received by the thrust stopper 58, and the reverse thrust is transmitted to the hull 5 through the swivel bracket 42, the mounting plate 49 and the clamp bracket 41. Although not shown in the above-described embodiment, the outboard motor 1 is a reverse lock device having a pivoting lever with a pawl and a pin with which the lever engages, as is well known in the art. Can also be equipped.

  In the outboard motor 1 configured as described above, the exhaust port 18a through which the exhaust gas of the engine 2 is discharged is formed below the propeller 3, so that the exhaust gas flows from the deepest part of the outboard motor 1 that is submerged in water. Be discharged into the water. For this reason, the position of the discharge port 18a is positioned lower than that of the conventional outboard motor, and the time required for the exhaust gas discharged from the discharge port 18a to rise to air is relatively long. Since the distance by which the hull 5 moves forward before the surface of the aircraft rises, it becomes difficult to hear the sound generated when the bubbles made of exhaust gas rise to the surface of the water.

  Since the outboard motor 1 is formed so that the discharge port 18a is positioned behind the propeller 3 in a normal traveling state, the bubbles made of the exhaust gas discharged from the discharge port 18a are behind the propeller 3. Is pushed by the water flow generated by the propeller 3 and is caused to flow backward, so that the sound generated when the bubbles float on the water surface becomes more difficult to hear from the ship. Further, the bubbles are vigorously stirred by the water flow generated by the propeller 3 and are finely crushed. At this time, the contact boundary between the water and the exhaust gas changes drastically, whereby the dense wave of the exhaust gas is attenuated and the exhaust noise is reduced. Further, when the bubbles are crushed finely, the rising resistance due to water increases, so that they are carried farther from the hull and reach the water surface, and the exhaust noise is reliably reduced.

  In this outboard motor 1, an exhaust passage 18 that guides exhaust gas to a discharge port 18 a is provided inside the lower casing 13 and in front of a gear coupling portion (bevel gear 37, bearing 24, etc.) between the drive shaft 20 and the propeller shaft 34. Since the exhaust passage 18 and the gear coupling portion are defined by the exhaust passage forming wall 18b, the exhaust passage forming wall 18b substantially functions as a protective member, The gear coupling portion can be protected from the front and the bottom. Therefore, even if the lower end of the outboard motor 1 collides with a foreign substance such as a riverbed, a seabed, a pile, or a driftwood, the gear coupling portion is not damaged and can continue to run. In this embodiment, the cooling water pump 21 is also protected from the front and the lower side by the exhaust passage inner wall 18, so that the cooling water can be continuously supplied to the engine 2 even after the collision.

  The exhaust passage 18 is disposed at the front of the lower casing 13 in the vertical direction, and the exhaust passage forming wall 18b is formed integrally with the lower casing 13, and the outer surface of the exhaust passage forming wall 18b is outside the lower casing 13. Since it becomes the surface, the exhaust gas flowing through the exhaust passage 18 collides with the lower casing 13 from the front via the exhaust passage forming wall 18b, and is reliably ensured by the relative flow of outside water flowing without peeling off the outer surface of the lower casing 13. To be cooled. For this reason, the temperature of the exhaust gas flowing through the exhaust passage 18 is lowered, the temperatures of the lubricating oil in the oil chamber 13b and the cooling water passing through the cooling water passage 40 are difficult to rise, and the bevel gear 37 and the cooling due to the deterioration of the lubricating oil. It is possible to prevent a decrease in durability of the engine 2 due to the rise of water.

  In the outboard motor 1 according to this embodiment, as shown in FIGS. 2 and 10, the axis of the tilt shaft 52 is directed in the left-right direction of the hull 5 while being attached to the side of the hull 5 by the mounting member 6. Therefore, it can be easily attached to the slats 5a and 5b of the double-ender hull 5 without any modification. Further, the outboard motor 1 moves forward in a state where it is attached to the side portion of the hull 5 as described above. For example, when a foreign object such as a riverbed, a seabed, a pile or a driftwood hits the protector 19 at the lower end. As shown in FIG. 19, the propulsion device 4 tilts up more than the maximum trim angle position around the tilt shaft 52. By this tilt-up operation, the impact force transmitted to the hull 5 side by the collision is alleviated. Therefore, even though the outboard motor 1 is mounted on the side of the hull 5, the outboard motor 1 is not easily damaged even if a foreign object hits it. When the propulsion device 4 is largely tilted up so that it jumps up, the cushion rubber 29 provided on the bracket 12c of the bottom cowl 12a comes into contact with the support block 54 of the swivel bracket body 51, so that an impact is generated. Alleviated.

  Furthermore, since the outboard motor 1 according to this embodiment can change the direction in which the thrust acts by rotating the propulsion device 4 with the steering handle 27, the outboard motor 1 is attached to the slats 5a and 5b of the hull 5. But maneuvering can be done easily. In particular, since the outboard motor 1 can change the traveling direction to any direction of 360 ° by changing the rotational position of the propulsion device 4, it is possible to further operate the boat while attached to the anchor plates 5a and 5b. It can be done easily.

Furthermore, the outboard motor 1 according to this embodiment has the support block 54 attached even when the clamp bracket 41 is attached to the saddle plates 5a and 5b that are largely inclined with respect to the longitudinal direction of the hull 5 in plan view. Since the tilt shaft 52 can be positioned so as to intersect the front-rear direction by rotating with respect to the working plate 49, the mounting position is not restricted by the shape of the hull 5. In addition, the outboard motor 1 can be attached to either the hull plate 5a on the right side of the hull or the hull plate 5b on the left side of the hull, so that the degree of freedom of the mounting position is further increased.
In addition, the outboard motor 1 according to this embodiment can be steered in the left-right direction even when the propulsion device 4 is rotated 180 ° so that the hull 5 moves backward, so that the outboard motor 1 is attached to the anchor plates 5a and 5b. Therefore, it is possible to more easily perform the ship maneuvering including the reverse operation.

  Further, the outboard motor 1 according to this embodiment can change the tilt angle (also referred to as trim angle here) of the propulsion device 4 by changing the rotational position of the thrust bracket 64 around the tilt axis. When traveling in shallow water, the position of the propeller 3 of the propulsion device 4 can be changed to the upper side to avoid contact with the riverbed, the seabed or foreign matter by tilting up (also referred to as trimming up here). Moreover, the outboard motor 1 can correct the inclination of the hull 5 in the front-rear direction by changing the tilt angle so that the thrust of the propeller 3 is also applied upward or downward.

Since the outboard motor 1 according to this embodiment can sail with the upper casing 11 and the lower casing 13 inclined so as to be rearwardly lowered, a polyethylene bag or floating algae floating in the water can be used. These foreign substances can flow smoothly backward without adhering to the front edges of the upper casing 11 and the lower casing 13. For this reason, the cooling water intake 38 of the cooling water pump 21 is not blocked by the foreign matter.
In the outboard motor 1 according to this embodiment, it is only necessary to operate the operation lever 70 to release the engaged state of the thrust stopper 58, and therefore, an operation of changing the tilt angle can be easily performed.
In the outboard motor 1 according to this embodiment, since the cavitation plate is not formed in the upper casing 11, the weight of the upper casing 11 can be reduced as compared with the conventional outboard motor.

In the outboard motor 1 according to this embodiment, the cooling water pump 21 and the cooling water inlet 38 are positioned below the upper edge of the propeller 3, and water always flows into the cooling water pump 21 even when the engine is stopped. The cooling water is supplied from the cooling water pump 21 to the engine 2 at the same time as the drive shaft 20 rotates when the engine is started. For this reason, the engine 2 can be reliably cooled.
As shown in FIG. 1, the outboard motor 1 according to this embodiment is formed so that the flat portion 16 of the upper casing 11 has a wing shape in cross section, and the upper casing 11 is sailed in a state where the upper casing 11 is inclined downward and rearward. Therefore, the upper casing 11 drains water, and the water hitting the upper casing 11 is difficult to splash upward.

  Although the outboard motor 1 in which the power unit is configured by the engine 2 is shown in the above-described embodiment, the present invention is also applicable to the outboard motor 1 equipped with an electric motor as a power unit instead of the engine 2. Can do. Further, in the above-described embodiment, the rotation center P1 of the upper casing 11 is positioned at a position away from the rotation center P2 of the swivel bracket 42. However, the outboard motor according to the present invention includes the rotation center P1. It can also be configured such that P1 and the rotation center P2 are located on the same axis. By adopting this configuration, the distance between the propulsion device 4 and the hull 5 becomes substantially constant even if the position attached to the hull 5 changes, so that the position is almost the same regardless of the position attached to the hull 5. The operation becomes even easier.

  In this application, the angle when the propeller 3 is in the water is used as the trim angle, and the angle when the propeller is out of the water surface is used as the tilt angle. However, the support angle, trim angle and tilt angle are substantially the same. It is. Similarly, the trim-up is the upward rotation of the propulsion device 4 when the propeller 3 is underwater, and the tilt-up is the upward rotation of the propulsion device 4 when the propeller 3 is underwater, or the propeller 3 It refers to the upward rotation of the propulsion device 4 that changes from being in water to being on the water surface.

1 is a side view of an outboard motor according to the present invention. 1 is a plan view of an outboard motor according to the present invention. It is sectional drawing of an upper casing upper part. FIG. 4 is a sectional view taken along the line IV-IV in the upper part of the upper casing in FIG. 3. It is sectional drawing of an upper casing lower part and a lower casing. It is the VI-VI sectional view taken on the line in FIG. It is the VII-VII sectional view taken on the line in FIG. It is the VIII-VIII sectional view taken on the line in FIG. It is sectional drawing of a swivel bracket. It is the XX sectional view taken on the line in FIG. It is the XI-XI sectional view taken on the line in FIG. It is sectional drawing which shows the state which attached the attachment member to the side part of the left side of a hull. It is sectional drawing which shows the state which rotated the swivel bracket with respect to the clamp bracket. 14 is a sectional view taken along line XIV-XIV in FIG. It is the XV-XV sectional view taken on the line in FIG. It is sectional drawing for demonstrating operation | movement of a thrust bracket. It is sectional drawing for demonstrating operation | movement of a thrust bracket. It is sectional drawing for demonstrating operation | movement of a thrust bracket. It is sectional drawing which shows a state when an impact is applied to the propulsion device 4 during sailing. It is a top view for demonstrating the position which attaches the outboard motor which concerns on this invention. It is sectional drawing equivalent to the XI-XI line cross section for showing another embodiment of a swivel bracket. It is a top view which shows the form which attached the outboard motor to the stern board.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outboard motor, 2 ... Engine, 3 ... Propeller, 4 ... Propulsion device, 5 ... Hull, 5a, 5b ... Saddle plate, 5c ... Stern plate, 6 ... Mounting member, 11 ... Upper casing, 13 ... Lower casing, DESCRIPTION OF SYMBOLS 18 ... Exhaust passage, 18a ... Discharge port, 18b ... Exhaust passage inner wall, 21 ... Cooling water pump, 34 ... Propeller shaft, 37 ... Bevel gear, W ... Water surface.

Claims (3)

  An outboard motor that has an exhaust port that discharges engine exhaust gas below the propeller.   The outboard motor according to claim 1, wherein the discharge port is formed behind the propeller. The outboard motor according to claim 1 or 2, wherein an exhaust passage for guiding exhaust gas to an exhaust port is provided inside the outboard motor casing, in front of a gear coupling portion between the propeller drive drive shaft and the propeller shaft. An outboard motor that is formed so as to pass below, and that the exhaust passage and the gear coupling portion are defined by an inner wall of the exhaust passage.

Images