JP5621529B2 - Muffler room and muffler cover structure for outboard engine case - Google Patents

Description

  The present invention relates to a muffler chamber and a muffler cover structure for arranging a muffler in an engine case of an outboard motor.

  Major outboard propulsion engines or propulsion systems include outboard motors, inboard motors, and inboard motors. Outboard motors are called outboard drives, etc., and are composed of an engine, its catchers, drive system gears, shafts, screws, etc., and are generally mounted on a transom board at the stern of the hull. . Typically, it is mounted on a small boat or the like and has a steering function and a tilting function.

Inboard / outboard motors are called inboard engines / outboard drives, etc., as a method of installing propulsion engines for small vessels, etc., and the engine is mounted on the stern part of the ship and the reduction gear, forward / reverse clutch and propeller are integrated. This is a drive unit arranged outside the transom board.
Furthermore, an inboard motor is typically one of the methods for installing a propulsion engine such as a small boat. Also called inboard drive, the engine, reduction gear, and forward / reverse clutch are installed in the center of the ship, the propeller shaft is extended toward the stern, and the propeller is installed in the water from the bottom of the ship. The rudder that determines the traveling direction of the ship is often installed behind the propeller.

  As described above, each of the boats has advantages and disadvantages due to the difference in the engine mounting structure. Of these, the muffler that constitutes the exhaust system in particular affects the exhaust performance, the silencing performance, and the engine performance, and it is extremely important how to arrange and configure them.

For example, in Patent Document 1, the exhaust of the inboard / outboard engine is guided to the outside of the ship via the catalyst (64) and the muffler (66). Unlike the vehicle, the exhaust of the marine engine is in the hull, so it is difficult for the exhaust to be cooled because it is not directly exposed to traveling wind. In this example, air is pumped and cooled between the exhaust pipe (26) and the protective pipe (32) around the exhaust pipe by a pump (42).
Further, in Patent Document 2, as in the conventional outboard motor and inboard / outboard motor, exhaust is performed in water or exhaust is directly performed in the air. Both adopt a wet method in which seawater is injected into the exhaust. In this wet method, the surrounding heat insulation pipe is not required to lower the temperature of the exhaust system, so the exhaust system itself does not become large, and the sound speed or sound pressure can be lowered.

JP 2001-173443 A Japanese Patent No. 2984027 Japanese Patent No. 3054962 JP 2003-120378 A

In Patent Document 1, the exhaust pipe (26) length is required to sufficiently cool the muffler (66) even when cooled as described above, and the volume of the installation portion is required. In order to obtain an air insulation layer, the protective pipe (32) must have a larger diameter than the exhaust pipe (26). Is difficult.
Moreover, in the thing of patent document 2, in an underwater exhaust system, since an engine (12) is fixed with respect to a hull (11) and a propulsion machine (13) is movable, such as a tilt or a steering, it is flexible in an exhaust system intermediate part. Part (bellows) is required.

  Furthermore, in the bellows structure of Patent Document 3, the bellows portion (46) is deteriorated due to an exhaust component and is bent due to steering and tilting, so it is difficult to maintain water tightness for a long period of time, and is periodically replaced. There was a need. Further, since the propulsion unit (7) must be removed for this replacement, the number of man-hours increases. On the other hand, in the air exhaust system, although the sound speed and the sound pressure are lowered, the muffler is not provided, so that a sufficient silencing performance cannot be obtained.

  Further, in Patent Document 4, the exhaust structure of a typical outboard motor is such that the engine (7) and the exhaust outlet (80) move integrally during steering or tilting, so that underwater exhaust is possible without a bellows structure. It is. However, since the exhaust system (46, 80) is installed integrally with the engine (7), it is difficult to install a sufficiently large catalyst. In addition, since the lower surface (lower cylinder) of the engine (7) and the water level at the time of stoppage are close to each other, deterioration of the catalyst and the oxygen sensor due to water exposure becomes a problem.

  In view of such circumstances, an object of the present invention is to provide a muffler chamber and a muffler cover structure for an outboard motor engine case that guarantees excellent exhaust performance and exhibits excellent effects in relation to peripheral components and the like. .

The muffler chamber and the muffler cover structure of the outboard motor engine case according to the present invention accommodate the engine inside the case, and in the engine case of the outboard motor equipped with a propulsion device outside the case, the muffler chamber is formed on the lower surface of the case body. provided a muffler accommodated in the muffler chamber has covered with the muffler cover, it said muffler chamber is formed along the shape of the muffler and exhaust hoses connected thereto at the outside of the case body, the case body The lower surface of the muffler chamber is formed so as to protrude downward in the center in the left-right direction along the ship bottom of the hull, and the muffler chamber in which the cylindrical muffler and the exhaust hose connected thereto are accommodated is the lower surface of the case body. A groove-like recess that is recessed outwardly toward the inside of the case body and extends in the left-right direction or both sides across the center of the case body in the left-right direction. The muffler cover covers the entire outer surface of the muffler chamber and the lower surface of the case body from the lower side, and is in close contact with the outer surface of the lower surface of the case body excluding the groove-shaped recess forming the muffler chamber. A close contact region is formed .

Further, in the muffler chamber and the muffler cover structure of the outboard motor engine case of the present invention, the muffler cover is formed in a substantially dish shape along the case body, and the upper peripheral edge thereof is on the front and rear and left and right side surfaces of the case body. On the other hand, it is fastened with a flat head screw.

Further, in the muffler chamber and muffler cover structure of the outboard motor engine case according to the present invention, the muffler cover is formed with a drain hole that communicates the inside and outside of the muffler chamber on the rear side of the rear end portion. And

  According to the present invention, a heavy muffler is disposed below the engine case, so that the center of gravity of the entire outboard motor is lowered and the stable traveling of the boat is ensured. Further, the muffler can be effectively protected without directly exposing the muffler to the fluid in water.

  Further, by attaching the muffler cover and smoothing the lower surface of the engine case, the transition to the sliding can be performed easily and accurately, and the fuel efficiency of the outboard motor is improved as a result of not requiring a large engine. Furthermore, by making the shape of the muffler cover consistent with the case main body, it is possible to realize a design with a sense of unity as the entire outboard motor.

It is a perspective view which shows the example of the ship or boat which mounts the outboard motor which concerns on this invention. It is a perspective view which shows the external appearance of the outboard motor of this invention. It is a front view which shows the external appearance of the outboard motor of this invention. It is a side view which shows the external appearance of the outboard motor of this invention. It is a rear view which shows the external appearance of the outboard motor of this invention. It is a perspective view which shows the structural example inside the engine case in the outboard motor of this invention. It is a disassembled perspective view of the main components inside the engine case in the outboard motor of the present invention. It is a perspective view which shows the structure and arrangement example of the engine unit of the outboard motor of this invention. It is a perspective view which shows the structure and arrangement example of the intake / exhaust system of the outboard motor of the present invention. It is a perspective view which shows the structure and arrangement example of the power transmission mechanism of the outboard motor of this invention. It is a perspective view which shows the structure and arrangement example of the frame of the outboard motor of this invention. It is a perspective view which shows the case cover open state in the engine case of the outboard motor of this invention. It is a bottom view showing an example of muffler arrangement in the engine case of the outboard motor of the present invention. It is a lower perspective view showing an example of muffler arrangement in the engine case of the outboard motor of the present invention. It is sectional drawing and the E section enlarged view which follow the II line | wire of FIG. It is sectional drawing which follows the II-II line of FIG. It is a fragmentary perspective view which shows the muffler chamber in the engine case of the outboard motor of this invention. FIG. 4 is a rear perspective view and a front perspective view showing the arrangement relationship between the muffler cover and the muffler in the engine case of the outboard motor of the present invention. It is the top view and front perspective view of the muffler cover in the engine case of the outboard motor of this invention.

Hereinafter, preferred embodiments of a muffler chamber and a muffler cover structure of an outboard motor engine case according to the present invention will be described with reference to the drawings.
FIG. 1 shows an example of a ship or a boat equipped with an outboard motor 10 according to the present invention. In this example, the ship is typically small and medium, and has a transom board 2 (stern board) at the rear of the hull 1. The outboard motor 10 is mounted using the transom board 2 as shown. Note that, in the main points of the respective drawings referred to below, the front (the bow side) is indicated by an arrow Fr, and the rear (stern side) is indicated by an arrow Rr. Moreover, the left-right direction (hull width direction) of a hull is shown by the arrow L and the arrow R, respectively as needed.

  First, in the hull 1 according to the present embodiment, a ship floor 3 is laid at the bottom of the hull 1 as shown in FIG. 1, and a transom board 2 is disposed at the rear end of the ship floor 3. A cockpit 4 is provided in the vicinity of the center of the ship floor 3, and devices, instruments, instruments, and the like necessary for steering including the handle 5 are disposed in the cockpit 4. The outboard motor 10 is integrally equipped with power, a propulsion device, a steering device, a tilt device, and the like, and is configured as a so-called all-in-one type. The outboard motor 10 can be operated if there are normal equipment such as a fuel tank and a battery on the hull 1 side. is there.

  In addition, the ship is not limited to the illustrated example, and there is also a hull having a bracket for mounting an outboard motor on the rear side of the transom board, that is, a stern plate or a part corresponding to the stern plate on the stern of the hull. The outboard motor 10 of the present invention can be effectively applied to a type having members.

  2 to 5 show the appearance of the outboard motor 10, FIG. 2 is a perspective view of the outboard motor 10, FIG. 3 is a front view, FIG. 4 is a side view, and FIG. The outboard motor 10 has an engine case 100, and an engine unit which is a power source described later is accommodated in the engine case 100, and a screw (propeller) is disposed below the rear portion of the engine case 100. Is driven to rotate. The engine case 100 also functions as an exterior member that constitutes the exterior of the outboard motor 10 and exhibits an exterior with a sense of unity as a whole.

  Referring also to FIG. 1, engine case 100 is configured as a housing having substantially the same width as the stern portion (typically, transom board 2) of hull 1. In this example, the basic form of the engine case 100 is a substantially rectangular parallelepiped, and the longitudinal direction of the rectangular parallelepiped is the hull width direction (hereinafter abbreviated as the ship width direction). The engine case 100 includes a case main body 101 that houses the engine unit and its peripheral components or members, and a case cover 102 that covers an upper opening 101a (see FIG. 12) of the case main body 101.

  Here, the engine unit accommodated in the engine case 100 and its peripheral components will be described. The outboard motor 10 of the present invention uses an internal combustion engine as a main power as its power unit, and drives this to drive the propulsion unit. FIG. 6 shows a configuration example inside the engine case 100 in the outboard motor 10, and FIG. 7 is an exploded perspective view of a main configuration inside the engine case 100. In the engine case 100, the engine unit 11 constituting the power unit is arranged and accommodated in a compact and well-balanced manner. In this embodiment, two engine units 11 are provided, and a pair of engine units 11 are arranged in a center distribution on the left and right sides of an engine case 100 in which the longitudinal direction of the casing is the ship width direction. Each engine unit 11 is connected to an intake system 12 and an exhaust system 13, and a power transmission mechanism 14 is coupled to each output end (crankshaft). The power transmission mechanism 14 is coupled to the propulsion unit 15 at the center in the left-right direction on the rear side of the engine unit 11, and these outboard motor components are mounted and supported on the frame 16 as shown in FIG.

  More specifically, the engine unit 11 uses a water-cooled in-line four-cylinder four-cycle gasoline engine in this example. The number of engine cylinders and the like can be appropriately changed as necessary, and is not limited to this example. Referring to FIG. 8, in engine unit 11, crankcase 17, cylinder block 18, cylinder head 19 and cylinder head cover 20 are integrally coupled so as to sequentially overlap, and an oil pan 21 is attached to the lowermost part. The crankshaft of each engine unit 11 is disposed along the ship width direction (left-right direction), and the engine output shaft coupled to the shaft end is disposed on both the left and right sides, that is, the engine of the right engine unit 11. The output shaft is arranged on the right side, and the engine output shaft of the left engine unit 11 is on the left side.

  Next, in the intake system 12, a single air cleaner 22 is disposed between the engine units 11 as shown in FIG. On the other hand, as shown in FIG. 8, intake manifolds 23 are coupled to the front side of the cylinder head 19 of the right engine unit 11 and to the rear side of the cylinder head 19 of the left engine unit 11, respectively. The air cleaner 22 is connected to each other via an intake pipe 24. An intake pipe 25 extends from the front surface of the air cleaner 22 to the hull 1 side in front of the engine case 100 (see FIG. 9), and takes in air from an air intake port at the tip thereof. The air intake is installed in a room or space that is not exposed to waves, splashes, rain, or the like in the hull 1. As shown in FIG. 8, each engine unit 11 branches from a single intake pipe 25 to a plurality (four in this example) of intake manifolds 23.

  In the exhaust system 13, as shown in FIG. 7 and the like, exhaust manifolds 26 are coupled to the rear side of the cylinder head 19 of the right engine unit 11 and to the front side of the cylinder head 19 of the left engine unit 11, respectively. Connected to a single exhaust pipe 27. An exhaust hose 28 is connected to the exhaust pipe 27, and a muffler 29 is connected to the exhaust hose 28. An exhaust hose 30 is connected to the muffler 29, and exhaust gas is discharged from an exhaust outlet 31 attached to the exhaust hose 30.

  The muffler 29 is installed outside the lower surface of the case body 101 of the engine case 100 as will be described later. In this case, the muffler 29, the exhaust hose 30 and the like are arranged so as not to substantially protrude from the lower surface of the case body 101, and the left and right sides of the rear side of the case body 101 are well balanced from the exhaust outlets 31 arranged near the lower portions. These are exhausted into water and will be described later.

  The power transmission mechanism 14 transmits the output of the engine unit 11 to the propulsion device 15. In the power transmission mechanism 14, a speed reducer 32 is connected to the engine output shafts of the left and right engine units 11 as shown in FIG. 10. A gear group is rotatably supported in a casing 33 of the speed reducer 32, and a drive shaft 34 is connected to the output shaft. The left and right drive shafts 34 are arranged concentrically and horizontally in the left-right direction, and are connected to the intermediate speed reducer 35 at the left-right center. The drive shaft 34 is connected to the speed reducer 32 and the intermediate speed reducer 35 via universal joints 36 and 37 at both ends.

  In the present embodiment, the intermediate speed reducer 35 includes a pair of input side bevel gears connected to the drive shaft 34 and an output side bevel gear meshing with these input side bevel gears. The output side bevel gear is connected to the second drive shaft in the drive shaft case 38, and the intermediate speed reducer 35, the drive shaft case 38, and the swivel bracket 39 are integrally coupled to each other. The second drive shaft extends downward from the intermediate speed reducer 35. These swivel brackets 39 and the like are rotatably supported by the case body 101 through a bearing 40 as will be described later.

  As shown in FIG. 10 and the like, the propulsion unit 15 is disposed below the drive shaft case 38. The propulsion device 15 includes a gear case 41 containing a gear for driving a propeller, and has a fin shape as a whole. A propeller 42 is mounted on the rear end portion of the gear case 41. The second drive shaft extends further downward through the drive shaft case 38 and extends into the gear case 41. A final reduction gear is configured in the gear case 41, and the propeller 42 can be rotationally driven through the final reduction gear.

  Further, a tilt mechanism and a steering mechanism for the propulsion device 15 are provided. Although a detailed description thereof will be omitted here, first, the intermediate speed reducer 35, the drive shaft case 38, and the entire propulsion unit 15 can be rotated up and down around the tilt axis by the tilt mechanism. The tilt axis T is set coaxially with the drive shaft 34, and the propulsion unit 15 can tilt around the tilt axis T as indicated by an arrow A in FIG. The tilt mechanism may include a so-called power trim tilt (PTT) or the like, and an electrohydraulic tilt mechanism may be configured.

  Further, the propulsion unit 15 can be rotated around the steering shaft S in the yaw direction (left-right direction) (yawing) by the steering mechanism as indicated by an arrow B in FIG. In this steering mechanism, for example, it has a steering cylinder that is hydraulically driven in an electro-hydraulic manner, and the propulsion unit 15 rotates in the left-right direction, that is, performs a steering operation by reciprocating along a steering rod using a hydraulic pump as a hydraulic source. be able to.

  The main components of the outboard motor 10 described above are mounted and supported on the frame 16 as shown in FIG. The frame 16 is formed using a material such as a steel pipe so as to have an outer shape substantially along a rectangular parallelepiped of a casing constituting the engine case 100 as shown in FIG. A plurality of engine mounts 43 for mounting and supporting the engine unit 11 are disposed at predetermined portions of the frame 16, and the engine unit 11 is mounted on the frame 16 through the engine mounts 43. A main bracket 44 to which a bearing 40 for supporting the swivel bracket 39 and the like described above is attached is attached to the rear portion of the frame 16.

  Further, a plurality of transom bolts 45 are attached to the front portion of the frame 16 facing the front. Outboard motor components such as the engine unit 11 are mounted on the frame 16, and the frame 16 mounting them is housed in the engine case 100. The transom bolt 45 passes through the front surface portion of the case body 101 of the engine case 100 and is fastened to the transom board 2, whereby the entire engine case 100 can be fastened and fixed to the transom board 2. The transom bolt 45 protruding from the case main body 101 is fitted with a seal or packing to ensure water tightness.

  Now, the engine case 100 will be described in more detail. As described above, the engine case 100 includes the case main body 101 that houses the engine unit 11 and its peripheral components, and the case cover 102 that covers the upper opening 101 a of the case main body 101. When the case cover 102 is closed with respect to the case main body 101, the inside of the engine case 100 becomes a substantially sealed space, and high water tightness is ensured. In this case, the constituent members of the outboard motor 10 are supported by the frame 16, and the frame 16 holds the engine unit 11 and is responsible for the propulsive force and steering force of the propulsion unit 15, that is, the load on the engine case 100 itself. It does not take. Further, as shown in FIG. 1, the engine case 100 also functions as an exterior member of the outboard motor 10 and is mounted on the outboard motor 10 so as to exhibit a unity appearance as a whole.

  As shown in FIGS. 2 to 4 and the like, on the rear surface side of the case main body 101, in the region from the rear surface portion to the bottom surface portion, it is formed to be recessed inward of the case main body 101 at the center in the ship width direction. A recess 103 is provided. Around this recess 103, a propulsion unit 15 constituting the propulsion device, its tilt and steering mechanism, and the like are disposed. The recess 103 is formed from the rear side of the case main body 101 toward the front, and is necessary so that the tilt mechanism and the steering mechanism or peripheral devices and members thereof do not interfere with the case main body 101 when the tilt or steering operation is performed. A sufficient gap is provided.

  As described above, equipment such as a fuel tank and a battery is provided on the hull 1 side, and these equipment and the outboard motor 10 are connected or coupled. In this case, as shown in FIG. 5, a plurality of through-holes 104 are formed in the form of making a hole between the front portion of the casing 101 and the transom board 2. That is, a through hole 104A for inserting the intake pipe 25 for supplying combustion air to the engine, a through hole 104B for inserting a fuel pipe for supplying fuel from the fuel tank to the engine, and the inside of the engine case 100 A through-hole 104C for passing a cylinder for ventilation air for ventilating the air is formed. Further, a cord or cable for electrically (including a control signal) or mechanical connection between a device or equipment or member in the engine case 100 and the control device on the hull 1 side is inserted. A hole 104D is formed. These through holes 104 are provided with watertight holding means (seal or the like) when the intake pipe 25 or the like is mounted.

  The case cover 102 constitutes an upper surface portion of the engine case 100, and is coupled to be rotatable via a hinge 105 in the vicinity of the rear upper end of the case main body 101 as shown in FIG. 2 or FIG. As shown in FIG. 12, the case cover 102 is rotated around the hinge 105 and opened to open the inside of the engine case 100, and thus the exposed engine unit 11 and the like inside the engine case 100 can be freely accessed. Become. The case cover 102 can be opened to easily check the inside, and the convenience of this type of work can be improved.

  As shown in FIG. 12, a seal 106 is laid on the closing portion or mating surface of the case main body 101 and the case cover 102, and the case cover 102 is closed with respect to the case main body 101, so that the engine case 100 has high water tightness. Secured / held. In this case, the seal 106 is laid over the entire circumference along the mating surfaces of the case main body 101 and the case cover 102. When the case cover 102 is closed, the case cover 102 is sandwiched between the case body 102 and the closed portion of the case main body 101, thereby obtaining high water tightness with respect to the engine case 100.

  In addition, when the case cover 102 is closed with respect to the case main body 101, a lock mechanism 107 is provided for fixing and holding the case cover 102 in its closed state. As the lock mechanism 107, for example, as shown in FIG. 12, a handle 108 rotatably attached to the case main body 101 and a handle receiver 109 provided on the case cover 102 are included. By rotating the handle 108 with respect to the handle receiver 109, both can be easily held in a locked state, and the locked state can be released if necessary.

  In the above case, the upper surface of the engine case 100, that is, the upper surface of the case cover 102 is flattened, so that the outboard motor 10 is smoothly and continuously connected from the hull 1 functionally and as a boat deck extension. Integrate to The upper surface of the case cover 102 is provided with a non-slip, and due to its anti-slip effect, it is possible to take in nets, catch fish caught, or take in personnel during rescue, which was impossible with conventional outboard motors. Not only is this possible, but it is possible to get on and off the boat from the stern by bringing the stern closer to the pier. In addition, as an anti-slip | skid, an unevenness | corrugation of a moderate magnitude | size may be provided in the upper surface of the case cover 102, or a separate anti-slip rubber etc. may be attached.

  Next, the muffler 29 is installed on the lower surface and outside of the case body 101 as described above. As shown in FIG. 13 and FIG. 14, the pair of mufflers 29 are arranged so as to correspond to the isosceles of a substantially isosceles triangle so that the pair of mufflers 29 have a substantially “C” shape when viewed from the bottom of the case body 101. Is done. In this case, the muffler 29 connected to the right engine unit 11 has a rear side upstream of the exhaust gas flow flowing through the muffler 29, and the muffler 29 connected to the left engine unit 11 has a front side upstream of the exhaust gas flow. Are arranged so that The central portion of the lower surface of the case main body 101 on which these mufflers 29 are disposed is substantially flat, and both the left and right sides of the central portion are inclined upward appropriately. The exhaust hose 30 connected to the right muffler 29 is disposed along the side of the muffler 29 and connected to the exhaust outlet 31 near the lower portion of the rear surface of the case body 101.

  The muffler 29 and the exhaust hose 30 are arranged so as not to protrude from the lower surface of the case main body 101. For this arrangement, a muffler chamber 110 for accommodating the muffler 29 and the exhaust hose 30 is formed on the lower surface of the case body 101. The muffler chamber 110 is recessed from the outside of the lower surface of the case body 101 toward the inside of the case body 101, and is convex inward at the bottom surface of the case body 101. The muffler chamber 110 has a substantially “C” shape corresponding to the arrangement of the muffler 29 and the like.

  As shown in FIGS. 15 to 17, the muffler 29 and the exhaust hose 30 are accommodated and disposed so as to fit completely in the muffler chamber 110. That is, the muffler chamber 110 is formed outside the case body 101 along the shape of the muffler 29 and the exhaust hose 30 connected thereto. In that case, as shown in FIG. 17, the outer periphery of the muffler 29 is pressed with a suitable force by the plurality of mounting brackets 111, and the muffler 29 is accurately fixed in the muffler chamber 110. The mounting bracket 111 is fastened and fixed to the case main body 101 side by bolts 112. By providing the muffler chamber 110 in this manner, uneven undulations are formed on the bottom surface of the case body 101, and thereby the rigidity of the case body 101, particularly around the bottom surface, can be effectively enhanced.

  The muffler 29 and the like arranged in the muffler chamber 110 as described above are covered with the muffler cover 113 as shown in FIG. 15 or FIG. The muffler cover 113 is engaged around the bottom of the case body 101, and in this state, is fastened and fixed by screws or bolts described later. By attaching the muffler cover 113, the lower surface of the engine case 100 becomes a very smooth surface. In this case, the muffler cover 113 is also formed in a substantially flat shape corresponding to the central portion of the lower surface of the case body 101. Further, as shown in FIGS. 2 and 3 and the like, a drain hole 113a is formed.

  Here, as shown in FIG. 15B, the muffler cover 113 is fastened to the case main body 101 by a plurality of flat head screws 114. As shown in the illustrated example, a female screw portion 115 is provided on the case body 101 side, and a flat head screw 114 is screwed into the female screw portion 115. As shown in FIGS. 18A and 18B, the flat head screw 114 is disposed along the upper peripheral edge of the muffler cover 113 which is formed in a plate shape, for example, as shown in FIGS. A plurality of locations are set at the bottom of the muffler cover 113 corresponding to.

  FIG. 18 shows a relative arrangement relationship between the muffler 29 and the muffler cover 113. The muffler 29 accommodated in the muffler chamber 110 of the case main body 101 is arranged so as to be accommodated in a thin dish-shaped recess of the substantially muffler cover 113 as shown in the figure.

  FIG. 19 further shows the configuration of the muffler cover 113 alone. As described above, the muffler cover 113 is attached to the lower surface of the case main body 101. When the muffler cover 113 is attached, the muffler cover 113 is in close contact with the lower surface of the case main body 101 in the region F of FIG. This region F corresponds to a portion of the case body 101 where the muffler chamber 110 that houses the muffler 29 is not disposed. That is, since the muffler chamber 110 is recessed in a concave shape, the muffler cover 113 is not in close contact with this part. Further, as shown in FIG. 19B, the drain hole 113a and the hole 113b through which the exhaust outlet 31 is inserted are formed in the rear end portion of the muffler cover 113.

  Further, the main configuration and the operation of the present invention will be described in summary. First, in the present invention, the exhaust gas once raised upward from the exhaust manifold 26 of the exhaust system 13 is mixed with water and led to the muffler 29 disposed below the engine case 100 via the exhaust hose 30. Unlike the stern drive boat, exhaust system parts such as the muffler 29 are not exposed to the outside, and there are no parts that are subject to bending due to tilting and steering operation, so weather resistance, light resistance, or mechanical deterioration is improved. Are better.

  In this case, since the muffler 29 is housed in the depression on the lower surface of the case main body 101 of the engine case 100, that is, in the muffler chamber 110, the contact area of the muffler cover 113 with the lower surface of the case main body 101 can be increased. As a result, the muffler cover 113 (the lower surface of the engine case 100) formed along the bottom 6 (see FIGS. 13 and 14) of the hull 1 is opened when the water flows on the bottom of the boat, and the water pressure rises upward. Is easily transmitted to the engine case 100 and the frame 16.

  Further, since the muffler 29 is disposed on the outer lower surface of the engine case 100, the temperature in the engine case 100 is not increased by exhaust heat. Since the engine is arranged higher than the stern drive boat, it is easy to make the engine dry by flooding or reverse flow.

  Further, the mating portion between the muffler cover 113 and the case main body 101 is smooth as a whole because the case main body 101 is bent by the thickness of the muffler cover 113 as shown in FIG. When the boat or the boat travels, the rising water flow is received by the muffler cover 113 so that a moment in the bow downward direction acts on the boat. Since this water flow is the maximum at the time of sliding transition, the muffler cover 113 serves as a lift generating device, facilitating the sliding transition. Accordingly, since it is not necessary to use a large engine that can make a sliding transition in a short time, the outboard motor 1 can be substantially reduced in size. In addition, it has superior acceleration performance compared to an outboard motor that does not have a sliding transition device and that has a center of gravity with an out bracket, which is separated from the hull.

  Further, the muffler cover 113 and the case main body 101 are joined by the flat head screw 114. By minimizing the protruding portion, it is difficult to be influenced by the surrounding water flow, and the fluid resistance is reduced. Further, by fastening with the flat head screw 114 in this way, the muffler cover 113 can be made difficult to be detached from the engine case 100. Further, by removing the flat head screw 114 which is a mounting bolt for the muffler cover 113, the inspection and maintenance work of the muffler 29 can be easily performed.

Further, the bottom portion of the muffler cover 113 has a flat surface and an oblique surface as shown in FIG. 19B and the like. When the outboard motor 1 is placed on the floor, the flat surface or the V-shaped platform is provided. Can be stabilized by applying an oblique surface.
An exhaust outlet 31 is provided on the rear surface of the muffler cover 113 to exhaust from a separate exhaust system below the water surface at low speeds, and from the position farthest from the driver's seat on the water surface at high speeds (sliding). , Exhaust noise and exhaust reaching the driver can be reduced. Further, a water drain hole 113a is formed at the rear end of the muffler cover 113 for draining water collected around the muffler 29 (during non-sliding) when the muffler 29 is pumped to the land (at the time of sliding).

In particular, according to the present invention, the muffler chamber 110 is provided on the lower surface of the engine case 100, and the muffler 29 accommodated in the muffler chamber 110 is covered with the muffler cover 113.
Thus, by placing the heavy wet muffler 29 at the lower part of the engine case 100, the center of gravity of the outboard motor 1 as a whole is lowered, and stable running of the boat is ensured. In addition, by attaching the muffler cover 113, the muffler 29 is not directly exposed to the fluid in the water and is not affected by the fluid on the muffler 29, so that the muffler 29 can be effectively protected.

  Further, by smoothing the lower surface of the engine case 100, a water flow rising from the rear end of the hull 1 before the run is received by the muffler cover 113, and the transition to the run can be performed easily and accurately. As a result of not requiring a large engine, the fuel efficiency of the outboard motor 1 is improved. Furthermore, by making the shape of the muffler cover 113 consistent with the case main body 101, a design with a sense of unity can be realized as the outboard motor 1 as a whole.

  The muffler chamber 110 is formed along the shape of the muffler 29 and the exhaust hose 30, thereby reducing the substantial volume of the muffler chamber 110. And when the muffler chamber 110 is located on the water surface, such as during gliding and landing, the water around the muffler 29 can be drained in a very short time, and work efficiency can be improved. Further, by providing the muffler chamber 110 in this manner, an uneven bead is formed on the bottom surface of the case body 101, and the rigidity of the case body 101, particularly around the bottom surface, can be effectively enhanced. Further, a relatively large contact area between the muffler cover 113 and the lower surface of the case body 101 is ensured, and resistance due to water flow is easily transmitted from the muffler cover 113 to the case body 101.

  Further, as described above, the muffler cover 113 is fastened to the case main body 101 with the flat head screw 114 to reduce the fluid resistance.

As mentioned above, although this invention was demonstrated with various embodiment, this invention is not limited only to these embodiment, A change etc. are possible within the scope of the present invention.
In the above embodiment, the number of flat head screws 114 used to fix the muffler cover 113 can be increased or decreased as necessary.

1 Hull, 2 Transom Board, 3 Ship Floor, 5 Handle, 6 Ship Bottom, 10 Outboard Motor, 11 Engine Unit, 12 Intake System, 13 Exhaust System, 14 Power Transmission Mechanism, 15 Propeller, 16 Frame, 17 Crankcase, 18 cylinder block, 19 cylinder head, 22 air cleaner, 23 intake manifold, 24 intake pipe, 25 intake pipe, 26 exhaust manifold, 27 exhaust pipe, 28 exhaust hose, 29 muffler, 31 exhaust outlet, 32 reducer, 33 casing, 34 Drive shaft, 35 Intermediate reducer, 36, 37 Universal joint, 38 Drive shaft case, 39 Swivel bracket, 40 Bearing, 41 Gear case, 42 Propeller, 43 Engine mount, 44 Main bracket, 45 Transom bolt, 100 Engine case, 101 Case body, 102 Case cover, 103 Recess, 104 Through hole, 105 Hinge, 106 Seal, 107 Lock mechanism, 110 Housing part, 111 Mounting bracket, 113 Muffler cover, 114 Flat head screw.

Claims (3)

In the engine case of an outboard motor that houses the engine inside the case and has a propulsion device outside the case,
The muffler chamber provided on the lower surface of the case body, not covering the muffler accommodated in the muffler chamber muffler cover,
The muffler chamber is formed along the shape of the muffler and the exhaust hose connected thereto on the outside of the case body,
The lower surface of the case body is formed so as to protrude downward in the left-right direction center part along the ship bottom of the hull,
The muffler chamber in which the cylindrical muffler and the exhaust hose connected to the cylindrical muffler are accommodated is recessed toward the inside of the case main body on the outer side of the lower surface of the case main body, and the center of the case main body in the left-right direction It is formed as a groove-like recess extending across the front and rear on one side or both sides in the left-right direction across the part,
The muffler cover covers the entire outside of the lower surface of the muffler chamber and the case main body from the lower side, and forms a close contact area that is in close contact with the lower outer surface of the case main body excluding the groove-like recess forming the muffler chamber. muffler chamber and the muffler cover structure for an outboard motor engine case, characterized in that the. The muffler cover is formed in a substantially dish shape along the case body, and an upper peripheral edge thereof is fastened to the front and rear and left and right side surfaces of the case body by flat head screws. The muffler chamber and muffler cover structure of the outboard motor case described in 1. The muffler chamber of the outboard motor engine case according to claim 1 or 2, wherein the muffler cover is formed with a drain hole for communicating the inside and outside of the muffler chamber on the rear side surface of the rear end portion. Muffler cover structure.

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