JP3475668B2 - Outboard motor - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to outboard motors.

[0002]

2. Description of the Related Art As an example of a layout of an engine exhaust system and a cooling system of an outboard motor equipped with a small engine, as shown in Japanese Patent Publication No. 19288/1990, an exhaust passage block is attached to a lower surface of an engine cylinder head. In addition, in some cases, an extension portion that projects directly below the exhaust passage block is continuously provided above the extension case below the engine, and an exhaust gas and cooling water discharge passage is formed inside this extension portion.

[0003]

However, if the extension case is extended directly below the exhaust passage block, that is, directly below the cylinder head, the extension case becomes large in size and weight, and the appearance may be impaired.

Further, when an exhaust gas exhaust passage is formed inside the extension, the high temperature exhaust gas hits the bottom of the oil pan,
There is a risk that the oil temperature of the lubricating oil will rise abnormally.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an outboard motor that is small in size and light in weight and has an improved appearance.

Another object of the present invention is to provide an outboard motor in which exhaust gas does not raise the oil temperature of lubricating oil.

[0007]

The outboard motor according to the present invention comprises:
To solve the problems described above, as described in claim 1, the extension case is provided at an upper end portion of the drive shaft housing, a crankcase constituting the lower portion of the engine on the extension case is fixed
With that, it provided the intake and exhaust ports in the cylinder head of the engine, and an exhaust passage extending downward from the exhaust port, exhaust within the drive shaft housing
The drive shuff above the cooling water pipe passing through the passage.
In an outboard motor equipped with a water pump driven by an engine, an exhaust passage is formed in a space formed between the inside of the extension case and the lower surface of the crankcase, and the exhaust passage is The exhaust passage from the exhaust port is connected by an exhaust communication pipe bent at about 90 °, and oil is provided inside the crankcase.
A pan and a cooling water passage are formed in the cooling water passage.
Guide cooling water from the water pump through the cooling water pipe
On the other hand, the cooling water that has cooled the engine is sent to the exhaust passage.
Drive shaft housing with exhaust gas flowing in
It is configured so as to be guided to the discharge passage in the chamber .

In order to solve the above-mentioned problems, as described in claim 2, a cooling water communication passage is integrally formed in the exhaust communication pipe, and a water jacket formed around the engine, The cooling water passage formed in the crankcase is communicated with the cooling water passage.

Further, in order to solve the above-mentioned problems,
As described in claim 3, the cooling water passage of the crankcase is projected downward to form a wall portion, and the exhaust gas flowing into the exhaust passage by the exhaust communication pipe is formed in the wall portion by the crank portion. It is configured to lead away from the bottom surface of the case.

[0010]

[0011]

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a right side view showing an example of an outboard motor according to the present invention. As shown in FIG. 1, the outboard motor 1 has a box-shaped engine cover 2 at its uppermost portion, and a vertical engine 3 is housed inside the engine cover 2. A steering handle 4 extends forward from a front portion (right side in FIG. 1) of the engine cover 2, and a throttle grip 5 for adjusting an engine output is provided at a tip thereof.

A drive shaft housing 6 is provided below the engine cover 2, and a gear case 7 is provided below the drive shaft housing 6.
A propeller shaft 8 is axially supported inside the gear case 7, and a propeller 9 is provided at the rear end of the gear case 7.

FIG. 2 is a vertical sectional view of the engine 3 portion of the outboard motor 1, and FIG. 3 is a sectional view taken along the line III-III in FIG. As shown in FIG. 2, a crankshaft 10 is vertically installed (vertical) in the engine 3 so as to be oriented substantially vertically.

As shown in FIGS. 1 and 2, a shaft pipe 11 is formed in the drive shaft housing 6, and the crank pipe 10 is formed in the shaft pipe 11.
The drive shaft 12 connected to the lower end extends downward, and the lower end of the drive shaft 12 has a shift device 13
Is linked to the propeller shaft 8 via. Engine 3
Is transmitted to the propeller shaft 8 through the drive shaft 12 and the shift device 13, and the propeller shaft 8 and the propeller 9 are switched by the switching operation of the shift device 13.
It is possible to switch the rotation direction of the normal and reverse, or shift to the neutral.

The upper portion of the drive shaft housing 6 is rotatably supported by the rotation support portion 16 of the clamp bracket 15, and the clamp bracket 15 is attached to the ship 1.
It is fixed to the transom 18 of 7. That is, the outboard motor 1
Is provided so as to be rotatable about 360 ° with respect to the boat 17, and is configured to be able to steer the boat 17 by swinging the steering handle 4 in the horizontal direction to change the direction of the entire outboard motor 1. It

By the way, the engine cover 2 is configured to be vertically separable, for example, and the lower cover 2a fixed to the lower portion of the engine 3 and the lower cover 2a are detachably attached with the seal member 19 interposed therebetween. It consists of an upper cover 2b. The steering handle 4 is provided integrally with the lower cover 2a, while an air inlet 20 and a waterproof cover 21 that also serves as a raising handle are provided in the upper rear portion of the upper cover 2b.

On the other hand, the engine 3 is, for example, a 4-cycle OH.
A V-type single-cylinder engine, for example, an engine case 2 which is vertically divided into two and is configured by joining a lower crankcase 23a and an upper cylinder block 23b.
Have three. The engine case 23 is fixed on the extension case 22 provided at the upper end of the drive shaft housing 6.

The cylinder block 23b is integrally formed with a cylindrical cylinder sleeve 24 extending rearward (left side in FIG. 2) in a direction orthogonal to the crankshaft 10, and a cylinder head 25 is provided at a rear end of the cylinder sleeve 24. And a head cover 26 are provided respectively.

A cylinder bore 27 is formed inside the cylinder sleeve 24, and a combustion chamber 28 which is aligned with the cylinder bore 27 is formed in the cylinder head 25. An ignition plug 29 is connected to the combustion chamber 28 from the outside.

FIG. 4 is a plan view of the upper surface of the crankcase 23a taken along the line IV-IV in FIG. 2 and 4
As shown in FIG. 3, the crankcase 23a includes an oil pan 30 for storing lubricating oil and a cooling water passage 31 which will be described later inside the crankcase 23a. The metal bearing 35 provided on the support portion 32 and the ball bearing 36 provided on the cylinder block 23b side.
The crankshaft 10 is rotatably supported by and. A pair of webs 10a and 10b are vertically spaced apart from each other in a substantially middle portion of the crankshaft 10, and a crankpin 10c is eccentrically provided between them.

Further, in the cylinder bore 27, the piston 3
7 is slidably inserted, and the piston pin 37a of the piston 37 and the crank pin 1 of the crankshaft 10
0c are connected by a connecting rod 38, whereby the reciprocating motion of the piston 37 in the cylinder bore 27 is converted into the rotary motion of the crankshaft 10.

A flywheel / magnet device 39 for power generation and a rope
A recoil type engine starting device 40 is provided.

An intake port 41 and an exhaust port 42 which are connected to the combustion chamber 28 are formed in the cylinder head 25.
An intake valve 43 and an exhaust valve 44 that open and close both ports 41 and 42 are arranged in the cylinder head 25, and a valve operating device 45 that opens and closes these valves 43 and 44 is also arranged.

Both ports 41, 42 are arranged vertically, the intake port 41 is arranged on the upper side, and the exhaust port 42 is arranged on the lower side. An exhaust passage 46 extends from the exhaust port 42 toward the lower surface of the cylinder block 23b.

FIG. 5 is a plan view of the extension case 22 provided on the upper portion of the drive shaft housing 6 taken along the line VV of FIG. As shown in FIGS. 2 to 5, an exhaust passage 47 is formed in a space formed between the inner center portion of the extension case 22 and the lower surface of the crank case 23a. This exhaust passage 47
Is connected to an exhaust passage 46 extending downward from the exhaust port 42 of the cylinder head 25 by an exhaust communication pipe 48. The exhaust communication pipe 48 is bent at about 90 °, and is configured to bend the exhaust gas discharged downward from the exhaust port 42 in the horizontal direction and guide it to the exhaust passage 47.

As shown in FIGS. 1, 2 and 5, a discharge passage 49 is formed around the shaft pipe 11 in the drive shaft housing 6 and an exhaust passage 46 is formed.
Exhaust gas from the exhaust passage 47 and the exhaust passage 49
Through the discharge shaft 50 provided in the lower portion of the drive shaft housing 6 and discharged into the water.

The engine 3 of the outboard motor 1 is a water-cooled engine, and a water jacket 51 is provided around the cylinder sleeve 24 and the cylinder head 25. Further, the water jacket 51 and the cooling water passage 31 of the crankcase 23a are connected to the exhaust communication pipe 4
8 are communicated with each other by a cooling water communication passage 52 formed integrally. Then, the cooling water passage 3 of the crankcase 23a
As shown in FIGS. 4 and 5, 1 communicates with a cooling water passage 53 formed inside the extension case 22 provided in the upper portion of the drive shaft housing 6.

Cooling water passage 31 of the crankcase 23a
Is formed so as to project downward and form a wall portion 54, and the wall portion 54 causes the exhaust gas flowing horizontally into the exhaust passage 47 by the exhaust communication pipe 48 to move away from the bottom surface of the crankcase 23 a, that is, the oil pan 30. In the present embodiment, it is configured so as to be guided downward (see arrow 55 in FIG. 2).

On the other hand, the cooling water for cooling the engine is taken in through a water intake 56 provided in the gear case 7, for example, and passes through a cooling water pipe 57 passing through the discharge passage 49 in the drive shaft housing 6 and the cooling water passage 53. Be led to. A water pump 58 driven by the drive shaft 12 is provided in the middle of the cooling water pipe 57.

The cooling water that has cooled the engine 3 is
The drainage passage 6 formed inside the extension case 22 provided at the upper portion of the drive shaft housing 6 by a drainage pipe (not shown) through the thermostat 59.
0, and is discharged into water through the discharge passage 49 in the drive shaft housing 6 together with the exhaust gas from the discharge port 50 provided in the lower portion of the drive shaft housing 6.

Next, the operation of this embodiment will be described.

An exhaust passage 47 is formed in a space formed between the inner center of the extension case 22 and the lower surface of the crank case 23a.
Is connected to an exhaust passage 46 extending downward from the exhaust port 42 of the cylinder head 25 by an exhaust communication pipe 48 bent at about 90 °, so that the extension case 22 does not extend directly below the cylinder head 25. The exhaust gas can be guided to the exhaust passage 49 in the drive shaft housing 6.

As a result, the size and weight of the extension case 22 can be reduced, and the size and weight of the outboard motor 1 as a whole can be reduced, and the degree of freedom in designing the extension case 22 and the engine cover 2 can be increased to improve the appearance. Can be planned.

Further, the cooling water communication passage 5 is provided in the exhaust communication pipe 48.
2 is integrally formed, and the water jacket 51 around the cylinder sleeve 24 and the cylinder head 25 and the cooling water passage 31 of the crankcase 23a are communicated with each other.
As described above, the extension case 22 can be made smaller and lighter and its appearance can be improved.

Further, the cooling water passage 31 of the crankcase 23a is projected downward to form a wall portion 54,
The wall portion 54 is configured to guide the exhaust gas flowing horizontally into the exhaust passage 47 by the exhaust communication pipe 48 downward so that the high temperature exhaust gas does not directly contact the bottom wall of the oil pan 30 and, as a result, the oil An abnormal rise in the oil temperature of the lubricating oil in the pan 30 can be prevented.

[0038]

As described above, according to the outboard motor of the present invention, the extension case is provided at the upper end of the drive shaft housing, and the crankcase constituting the lower part of the engine is fixed on the extension case. In addition, in an outboard motor provided with an intake / exhaust port in the cylinder head of the engine and an exhaust passage extending downward from the exhaust port, between the inside of the extension case and the lower surface of the crankcase. An exhaust passage is formed in the space sandwiched between
The exhaust passage and the exhaust passage from the exhaust port are approximately 9
Since the exhaust communication pipe bent at 0 ° was used for connection, the extension case can be made smaller and lighter and its appearance can be improved.

Further, a cooling water communication passage is integrally formed in the exhaust communication pipe, and a water jacket formed around the engine and a cooling water passage formed in the crankcase are connected by the cooling water communication passage. Since they are communicated with each other, the extension case can be made smaller and lighter and its appearance can be improved.

Further, the cooling water passage of the crankcase is projected downward to form a wall portion, and the exhaust gas flowing into the exhaust passage by the exhaust communication pipe is formed from the bottom surface of the crankcase at the wall portion. Since it is configured to be guided in the direction away from, it is possible to prevent an abnormal increase in the oil temperature of the lubricating oil in the oil pan.

[Brief description of drawings]

FIG. 1 is a right side view showing an embodiment of an outboard motor according to the present invention.

FIG. 2 is a vertical sectional view of an engine portion of an outboard motor.

FIG. 3 is a sectional view taken along the line III-III in FIG.

FIG. 4 is a plan view of the upper surface of the crankcase taken along the line IV-IV in FIG.

5 is a plan view of the extension case taken along the line VV of FIG.

[Explanation of symbols]

1 outboard motor 3 engine 6 Drive shaft housing 10 crankshaft 22 extension case 23 engine case 23a crankcase 23b Cylinder block 25 cylinder head 30 oil pans 31,53 Cooling water passage 41 intake port 42 exhaust port 46,47 Exhaust passage 48 Exhaust communication pipe 49 Discharge passage 51 water jacket 52 Cooling water communication passage 54 Wall of cooling water passage

Claims (3)

(57) [Claims] 1. A The extension case is provided at an upper end portion of the drive shaft housing, together with a crankcase constituting the lower portion of the engine on the extension case is fixed, provided intake and exhaust ports in the cylinder head of the engine, this An exhaust passage extending downward from the exhaust port, and the drive shaft housing described above.
In the middle of the cooling water pipe passing through the discharge passage inside
In an outboard motor including a water pump driven by a shaft , an exhaust passage is formed in a space formed between the inside of the extension case and the lower surface of the crankcase , and the exhaust passage is Above exhaust
Exhaust communication with the exhaust passage from the port bent at about 90 °
Thus while connected to the tube, the inside of the crankcase
An oil pan and a cooling water passage are formed in the
Cooling from the water pump through the cooling water pipe
While guiding water, the cooling water that has cooled the engine is drained.
The drive shaft with the exhaust gas flowing into the air passage
An outboard motor configured to be guided to a discharge passage in a housing . Wherein the cooling water communication passage to the exhaust communicating pipe is integrally formed, a water-di formed around the engine
And jacket cooling water passage formed in the crankcase
The outboard motor according to claim 1, wherein the passage is communicated with the cooling water communication passage . 3. by projecting a cooling water passage of the crankcase downward to form a wall portion, the bottom surface of the crankcase exhaust gas flowing into Therefore the exhaust passage to the exhaust communicating pipe in the wall The outboard motor according to claim 2, wherein the outboard motor is configured to be guided away from the vehicle.