JP3491776B2 - Outboard motor cooling structure - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cooling structure for an outboard motor mounted on a small boat, and more particularly, to an overflow pipe for discharging cooling water from an upper case. Related to the structure. [0002] In an outboard motor mounted on a small boat, a housing of the entire outboard motor is generally formed by a top cowl, an upper case and a lower case, and an exhaust guide is provided between the top cowl and the upper case. The engine is mounted in the top cowl on the upper surface of the exhaust guide, and the engine is mounted on the top cowl on the upper surface of the exhaust guide, and is rotated by the engine via the drive shaft, the shift conversion gear, and the propulsion shaft. Thrusters (screw)
Is supported by the lower case. [0003] The exhaust passage from the engine in such an outboard motor extends downward from the engine so that exhaust gas is discharged from the lower case below the water surface to the outside through the upper case. The exhaust passage is opened in the lower case, but it is necessary to make the exhaust passage as long as possible to effectively reduce exhaust noise and secure a space for installing a catalyst that purifies exhaust gas. Come. However, in the conventional outboard motor, since the exhaust passage has a structure extending only vertically from the engine, there is a limit to extending the exhaust passage without increasing the size of the outboard motor itself. Also, if a catalyst is installed in the exhaust passage, water that has entered from below the exhaust passage may come into contact with the catalyst depending on the attitude of the hull. Problem arises. [0005] In order to solve the above-mentioned problems while reducing the size of the outboard motor itself without increasing the size of the outboard motor, a catalyst is accommodated in the exhaust passage of the outboard motor below the engine under the exhaust guide. To form a bag-shaped inflation chamber,
It has been proposed by the present applicant that a folded portion that extends once upward from the expansion chamber and then bends downward is formed by a riser and a return pipe, and the folded portion is arranged in the hull width direction. [0006] In the above-mentioned outboard motor, external water (sea water or the like) is used as cooling water for cooling the engine and the exhaust passage. A pump driven in conjunction with the drive shaft of the motor continuously pumps up cooling water and supplies it to the engine above the outboard motor.After cooling the engine, it is dropped into the upper case and the expansion chamber, return pipe, etc. After cooling the exhaust passage, the cooling water accumulated in the upper case is discharged from the overflow pipe formed integrally with the side wall of the upper case to the outside of the machine via the lower case. However, in the above cooling structure, since the overflow pipe is usually formed integrally with the side wall of the upper case, the manufacture of the upper case itself is troublesome. There is a problem that the outboard motor becomes large due to its thickness itself. An object of the present invention is to solve the above-mentioned disadvantages of the outboard motor cooling structure, and more specifically, to form an overflow pipe separately from an upper case, An object of the present invention is to provide a cooling structure for an outboard motor that can be easily formed in an upper case itself by preventing the outboard motor from being enlarged by arranging it compactly between members in the case. And [0009] The present invention SUMMARY OF], in order to achieve the solution to and the purpose of the above problems, the top cowl and up
The lower surface of the exhaust guide placed between the par cases
A bag-shaped cover body is attached to the
Is formed in the expansion chamber and communicates with the expansion chamber.
Pipe has its lower end opening in the lower case.
To the outside of the cover in the upper case
In the outboard motor installed, the lower end of the return pipe
Is supported on the bottom wall of the upper case via a sealing member.
And fall from the cooling water jacket of the exhaust guide.
When the accumulated cooling water is collected in the upper case,
The cooling water accumulated in the upper case
The overflow pipe for discharging into the upper end
Is detachably fixed to the upper part of the upper case, and its lower end
Is fitted into the fitting hole in the bottom wall of the upper case
At the bottom of the overflow pipe and under the upper case
It is characterized in that it is formed as a member separate from the upper case so that the end is flush with the upper case, and is disposed in a concave portion of a joint between the expansion chamber and the return pipe. According to the above construction, the upper case is provided.
By storing cooling water inside, the expansion chamber and return pipe
It can be cooled effectively. Moreover, the upper case
Overflow for discharging the accumulated cooling water into the scan
The pipe must be formed as a separate member from the upper case.
With this, the structure of the upper case is simplified and its manufacture is facilitated, and the overflow pipe formed as a separate member is disposed in the space between the components in the upper case without wasting space, so the upper case itself However, the outboard motor can be made compact as a whole without increasing its size. An embodiment of a cooling structure for an outboard motor according to the present invention will be described below with reference to the drawings. As shown in FIG. 1, the outboard motor 1 has a swivel arm 4 pivotally attached to a clamp bracket 3 fixed to a rear tail plate 2 of the hull so as to be vertically swingable.
It is elastically supported via upper and lower two damper members 5a, 5b, and its housing is formed by a top cowl 6, an upper case 7, and a lower case 8, and an engine 9 is housed in the top cowl 6. A propulsion device (screw) 10 rotatably driven by an engine 9 is supported on the lower case 8. The top cowl 6 that houses the engine 9
An exhaust guide 11 is disposed between the bottom cowl 6b and the upper case 7 so as to separate the inside of the top cowl 6 and the inside of the upper case 7 from each other. The bottom guide cowl 6b is fixed to the upper surface periphery of the exhaust guide 11 and the upper case 7 is fixed to the lower surface periphery of the exhaust guide 11 by bolting. The engine 9 mounted in the top cowl 6 has a crankshaft 12 common to each cylinder arranged vertically, and three pairs of cylinders 9a are arranged as shown in FIG.
The exhaust ports of the three cylinders that are vertically overlapped with each other are arranged so as to form a V bank, and after being merged, each is led to a pair of exhaust ports 9b formed on the lower surface of the engine. An upper end of a drive shaft 15 which vertically traverses the inside of the upper case 7 is connected to an output portion 12a at the lower end of the crankshaft 12 placed vertically.
A bevel gear 15a meshed with a shift conversion gear portion 16a of a propulsion shaft 16 that is rotatably supported by the lower case 8 and has a propulsion device 10 spline-coupled to its rear end is connected to the lower end of the drive shaft 15. On the way, as shown in FIG.
A cooling water pump 17 that operates in conjunction with the drive shaft 15 is provided. The exhaust guide 11 provided between the bottom cowl 6b of the top cowl 6 and the upper case 7 is manufactured by die casting using an aluminum alloy as a material, and as shown in FIG. A mounting seat 11a for mounting the upper damper member 5a is formed on the upper surface, and a pair of exhaust holes 11b communicating with a pair of exhaust ports 9b of the engine 9 is formed behind the mounting seat 11a. Is provided on one side with an expansion chamber communication hole 11c.
However, return pipe communication holes 11d are formed on the other side so as to penetrate the exhaust guide 11 vertically. The exhaust guide 11 is provided with a cooling water jacket 11e surrounding the expansion chamber communication hole 11c and the return pipe communication hole 11d.
A cooling water jacket 11m is provided as a closed space formed in the exhaust guide 11 along one side of the exhaust hole 11b below 1a, and the cooling water jacket 11e and the cooling water jacket 11m are separated by a partition wall. ing. On the lower surface of the exhaust guide 11, a bag-like cover body 18 is provided so as to cover the pair of exhaust holes 11b and the expansion chamber communication holes 11c, and a return pipe 19 is provided on the outside of the cover body 18. As shown in FIG. 7, the cover body 18 and the return pipe 19 are integrally formed by die casting with an aluminum alloy so that the opposing portions of the respective side walls serve as a common boundary wall. ing. A peripheral flange 18a is formed continuously on the upper peripheral edge of the cover body 18 and the return pipe 19. The body 18 and the return pipe 19 are attached to the lower surface of the exhaust guide 11. In this embodiment, as shown in FIG.
Although the cover body 18 and the return pipe 19 are formed integrally, the present invention is not limited to such a configuration, and the cover body 18 and the return pipe 19 can be formed separately as shown in FIG. is there. In any case, the bag-shaped cover body 18 is attached to the lower surface of the exhaust guide 11 to form an expansion chamber 20 forming a closed space inside the cover body 18 and a pair of exhaust holes of the exhaust guide 11. Exhaust pipes 21 made of heat-resistant stainless steel that are not melted by exhaust heat are connected to the respective exhaust pipes 11b.
Are open in the expansion chamber 20. In the expansion chamber 20, the cylindrical catalyst 22 is further positioned behind the exhaust pipe 21 so that the cylindrical catalyst 22 moves closer to the longitudinal center line of the outboard motor as it goes down in the front-rear direction and the width direction. The upper part is inserted into the expansion chamber communication hole 11c in a state of being inclined with respect to the exhaust guide 11, and via a ring-shaped flange 23 obliquely fixed to the outer periphery of the upper part of the catalyst 22 by welding or the like. Are fixed to the periphery of the expansion chamber communication hole 11c on the lower surface of the exhaust guide 11 by bolting. The exhaust guide 11 of the catalyst 22
As shown in FIG. 1, a step 18b is formed on the rear side wall of the cover body 18 so that the catalyst 22 does not come into contact with the cover body 18 as shown in FIG. A heat insulating space is formed between the catalyst and the catalyst 22. The return pipe 19 located on the outer side of the cover 18 extends downward to reach the lower end of the upper case 7, and its lower end opening 19 a opens into the lower case 8, via the lower case 8. The lower end of the return pipe 19 is supported by the lower end of the upper case 7 via a seal member 37, as shown in FIG. The lower end of the case 7 is closed. As shown in FIGS. 2 and 6, a front expansion chamber 25 is formed in front of the return pipe 19, and idle exhaust is performed so that the front expansion chamber 25 communicates with the inside of the return pipe 19. The opening 24 is opened, and a rear expansion chamber 27 and an idle hole 28 communicating with the rear expansion chamber 27 are formed at the rear end of the exhaust guide 11. The front expansion chamber 25 above the return pipe 19
And the rear expansion chamber 27 at the rear end of the exhaust guide 11 is communicated between the cover body 18 and the return pipe 19 by an idle passage 26 formed with the lower surface of the exhaust guide 11 as a ceiling wall. The pipe 19 includes an idle exhaust port 24, a front expansion chamber 25,
The idle passage 26, the rear expansion chamber 27, and the idle hole 28 also communicate with the outside. On the upper surface of the exhaust guide 11, an upstream opening 30a is formed in order to form a folded portion of the exhaust passage.
And the upper bent portion 30b and the downstream opening 30c substantially reverse U
As shown in FIG. 3, a highlighter 30 formed in a character shape is disposed so as to bend in the width direction of the hull, and the bottom surface 30d of the upper bent portion 30b of the highlighter is located at the lowermost portion of the engine. And the upstream opening 30a is connected to the expansion chamber 2 via the expansion chamber communication hole 11c.
0, the downstream opening 30c is formed in the return pipe communication hole 11
Each of them communicates with the return pipe 19 via d. Above the highlighter 30 which is located outside the lower rear portion of the engine 9 and is disposed on the upper surface of the exhaust guide 11, a CD is provided above the V bank of the engine 9.
An I unit 41 is provided, and a regulator 42 is provided above the CDI unit 41 and near the air intake 43. The diameter and the bending radius of the enhancer 30 are set so as to minimize the influence on the engine output. Although not shown, the upstream opening 30a is provided.
And a portion surrounded by the upper bent portion 30b and the downstream opening 30c, a concave portion opened to the opposite side to the engine 9 is formed, and in order to fix the bottom wall of the concave portion to the upper surface of the exhaust guide 11, Bolts are located. As described above, since the recess is formed on the opposite side of the engine 9 and the bolt for fixing the center of the highlighter 30 is disposed in the recess, the engine 9 is not obstructed. The bolt can be easily attached and detached. The enhancer 30 has an exhaust passage 30
a, 30b, and 30c so as to surround the outer surfaces thereof, that is, the cooling water jacket 30e on the inner peripheral side and the exhaust passages 30a, 30b, and 30c surrounded by the exhaust passages 30a, 30b, and 30c shown in FIG. A bag-shaped cooling water jacket 30e is formed such that all of the outer peripheral side cooling water jacket 30e communicates with each other. Cooling water jacket 30e of the riser
Is connected to the cooling water jacket 11e of the exhaust guide through an inlet hole 30h opened at the bottom thereof, and is connected to a supply hose 33 connected to an outlet hole at the top thereof.
Thereby, it communicates with a cooling water jacket 9c formed on the outer cover of the exhaust manifold of the engine 9. When the expansion chamber 20 and the return pipe 19 are connected by the enhancer 30, the engine 9
The exhaust gas discharged from the exhaust port 9b passes through the exhaust pipe 21, expands in the expansion chamber 20, is purified by the catalyst 22, and then passes through the enhancer 30 to the return pipe 19.
And the lower end 19a of the return pipe during normal running
Is discharged into the lower case 8 and into the water through the propulsion device 10. During idle operation, the idle hole passes through the front expansion chamber 25, the idle passage 26, and the rear expansion chamber 27 from the idle exhaust port 24. 28 to the atmosphere. In the above outboard motor, as shown in FIG. 2, a supply pipe 31 connected to the cooling water pump 17 serves as a cooling water passage for cooling the engine and the exhaust passage.
However, as shown in FIG. 9 , the cooling water pumped upward by the cooling water pump 17 extends upward inside the upper case 7 outside the cover body 18 and the return pipe 19 , and flows into the exhaust guide 11 through the inflow hole 11f. Sent to An inflow hole 11f to which a supply pipe 31 from the cooling water pump 17 is connected is opened at a lower surface near the center in the front-rear direction of the exhaust guide 11, and is covered by a cover member 18 and a return pipe 19 below the exhaust guide. It is located at a place outside the part where The cooling water supplied to the inflow hole 11f of the exhaust guide 11 is supplied to a first passage 11w for directly supplying the cooling water to the engine 9 in the exhaust guide 11.
The cooling water that is branched by the second passage 11v that supplies the cooling water to the cooling water jacket 11e of the exhaust guide and flows toward the first passage 11w passes directly through the water passage in the exhaust guide 11 to the cooling water jacket 9c of the engine 9.
And the cooling water flowing to the second passage 11v side is supplied to the enhancer 30 via the cooling water jacket 11e. The cooling water jacket 11e formed in the exhaust guide 11 covers the upper part of the expansion chamber 20, and the expansion chamber communication hole 11c and the return pipe communication hole 11d.
And is formed as one continuous hollow closed space surrounding the periphery of the exhaust guide 1 only through the inflow hole 11f and the outflow hole 11g.
Each outflow hole 11g opened on the upper surface of FIG.
As shown in the figure, the liquid crystal display is arranged so as to be connected to the inflow hole 30h formed facing the highlighter 30 side. From the second passage 11v, the cooling water jacket 11
e, the cooling water supplied to the exhaust chamber 11b, the expansion chamber communication hole 11c, the return pipe communication hole 11d, and the expansion chamber 20.
Is cooled, and then supplied to the enhancer 30 through each outflow hole 11g on the upper surface of the exhaust guide 11. Exhaust guide cooling water jacket 1
The cooling water supplied from 1e to the riser 30 is cooled by the cooling water jacket 30e and then supplied to the supply hose 3 from the top of the cooling water jacket 30e.
After cooling the engine 9 together with the cooling water supplied to the cooling water jacket 9c of the engine 9 via the third passage 3 and directly supplied to the cooling water jacket 9c of the engine 9 via the first passage 11w, as shown in FIG. As described above, it flows down from the inflow hole 11k on the upper surface of the exhaust guide 11 into the cooling water jacket 11m of the exhaust guide. The cooling water jacket 11m formed in the exhaust guide 11 covers the upper part of the expansion chamber 20, and is formed as one hollow closed space along one side of the exhaust hole 11b below the mounting seat 11a. As shown in FIG. 10, the inflow hole 11k and the outflow hole 11n
Only through the cooling water jacket 1
1e is partitioned by a partition wall. Cooling water jacket 1 for exhaust guide
The cooling water flowing into the cooling water jacket 1m cools the mounting seat 11a, the exhaust hole 11b, and the upper part of the expansion chamber 20 in the cooling water jacket 11m, and then covers the cooling water from the outlet hole 11n opened to the side of the lower surface of the exhaust guide 11. After falling into the upper case 7 through a drop hole 18d opened in the peripheral edge of the flange portion 18a of the body 18, it accumulates in the upper case 7, cools the expansion chamber 20 and the return pipe 19, and then passes through the overflow pipe 34. It is discharged from the lower case 8 to the outside. The overflow pipe 34 for discharging the cooling water accumulated in the upper case 7 to the lower case 8 is formed as a separate member from the upper case 7 as shown in FIG. It is fixed to the upper part of the upper case 7 by bolts 36 via an attachment member 35. The lower end of the overflow pipe 34 is flush with the lower end of the upper case 7, is open in the lower case 8, and is fitted into the fitting hole 7a in the bottom wall of the upper case. By lowering the lower end position of the overflow pipe 34 and lowering the position of the upper case bottom wall, the amount of water accumulated in the upper case 7 can be increased. Since the lower end of the overflow pipe 34 is flush with the lower end of the upper case 7, the lower end of the overflow pipe 34 does not project downward from the lower end surface of the upper case 7, and the overflow pipe 34 is assembled. Even when the attached upper case 7 is placed on a table, the lower end of the overflow pipe 34 is not damaged. The overflow pipe 34 fixed to the upper and lower ends of the upper case 7 and extending vertically along the side wall of the upper case 7 as shown in FIG.
As shown in FIG. 2, the cover member 18 and the return pipe 19 forming the expansion chamber 20 are disposed so as to be located in a concave portion 38 formed at a joint portion. In this embodiment using an outboard motor as described above, when the propulsion unit 10 is driven to rotate via the drive shaft 15 and the propulsion shaft 16 by the operation of the engine 9, the ship is running. Exhaust gas from the engine is introduced from the exhaust pipe 21 into the expansion chamber 20, where it is expanded,
Higherizer 30 and return pipe 19 which are purified by 2
And is discharged into the water from the rear end of the propulsion device 10 through the inside of the lower case 8. At this time, since the enhancer 30 bent in the width direction of the hull is provided above the exhaust guide 11, the entire exhaust passage is formed to be long and compact without changing the vertical dimension of the exhaust passage. That is, the exhaust noise is effectively reduced. Also, even if the water level relative to the outboard motor changes due to the running posture of the hull, the riser 30 above the exhaust guide 11 returns to the return pipe 19 and the expansion chamber 18.
, And this portion serves as a barrier, so that water that has entered the return pipe 19 does not enter the expansion chamber 20 of the cover body 18, 22 caused by contact of seawater that has entered the sea
The purification performance of the fuel cell is prevented from being deteriorated. Further, since it is not necessary to integrally form the overflow pipe portion on the side wall of the upper case 7, the structure of the upper case 7 itself can be simplified and its manufacture can be facilitated. The overflow pipe 34 is disposed in the concave portion 38 at the joint between the cover body 18 and the return pipe 19, and the components are disposed in the upper case 7 without wasting space. The upper case becomes compact without increasing its size. According to the outboard motor cooling structure of the present invention as described above , the cooling water can be stored in the upper case.
Effectively cooling the expansion chamber and return pipe
Can be. Moreover, the cooling water accumulated in the upper case
By forming the overflow pipe for discharging air into a separate member from the upper case and compactly arranging it in the upper case, the manufacture of the upper case becomes easy, and the upper case part of the outboard motor is also provided. Can be formed compact without increasing the size.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a partially sectional left side view schematically showing an outboard motor to which an embodiment of a cooling structure according to the present invention is applied. FIG. 2 is a partial cross-sectional explanatory view from the right side of the outboard motor shown in FIG. 1; FIG. 3 is a partially sectional explanatory view from the back of the outboard motor shown in FIG. 1; FIG. 4 is a top view of an engine portion of the outboard motor shown in FIG. 5 is a top view of an exhaust guide portion of the outboard motor shown in FIG. FIG. 6 is a top view of a portion below the exhaust guide of the outboard motor shown in FIG. 1; FIG. 7 is a sectional rear view showing an exhaust passage and an upper case portion of the outboard motor shown in FIG. 1; FIG. 8 is a sectional rear view showing another example of the portion shown in FIG. 7; FIG. 9 is an explanatory longitudinal sectional view showing an arrangement state of overflow pipes in the outboard motor shown in FIG. 1; FIG. 10 is a cross-sectional view of the exhaust guide and the upper case along the line AA in FIG. 5; FIG. 11 is a cross-sectional view of the outboard motor shown in FIG. 1, taken along line BB of FIG. 7, showing the arrangement of overflow pipes; [Description of Signs] 1 Outboard motor 6 Top cowl 7 Upper case 8 Lower case 11 Exhaust guide 18 Cover body 19 Return pipe 20 Expansion chamber 34 Overflow pipe 37 Seal member

Claims (1)

(57) [Claims] [Claim 1] Arranged between the top cowl and the upper case
A bag-like cover body is provided on the lower surface of the installed exhaust guide.
By being attached, the inside of the cover body forms an expansion chamber.
And a return pipe communicating with the expansion chamber is provided thereunder.
So that the end opening is opened in the lower case.
-Outboards located outside the cover in the case
In the machine, the lower end of the return pipe is
And is supported by the bottom wall of the upper case.
The cooling water dropped from the cooling water jacket of the guide is the upper
-It is settled in the case and the upper
Drain the cooling water accumulated in the case into the lower case
Overflow pipe for the upper case
It is detachably fixed to the upper part of the base, and its lower end is upper
With the fitting fixed in the fitting hole in the bottom wall of the case,
The lower end of the flow pipe is flush with the lower end of the upper case
A cooling structure for an outboard motor, wherein the cooling structure is formed as a member separate from the upper case, and is disposed in a concave portion of a joint portion between the expansion chamber and the return pipe.