JP2000170542A - Outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an outboard motor wherein a structure is simplified, an engine is compact and costs are reduced. SOLUTION: In an outboard motor 1 having a crankshaft 9 vertically arranged in an engine 3, the engine 3 is provided with a cylinder head 19 having an intake port 33, the cylinder head 19 is disposed in the bow side, a carburetor 37 is connected to the cylinder head 19, and a drive shaft 11 connected to the crankshaft 9 is offset disposed in the bow side more than the crankshaft 9.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an outboard motor.

[0002]

2. Description of the Related Art An engine used for an outboard motor is generally a vertical (vertical) engine in which a crankshaft is arranged in a vertical direction. Usually, a crankcase is mounted on a front side (bow side) of the outboard motor, and a cylinder is mounted on a cylinder. Rear head (stern side)
Are arranged respectively.

[0003] When the engine is a two-stroke engine, the carburetor is connected to the crankcase, and therefore is arranged on the front side of the outboard motor like the crankcase.

On the other hand, when the engine is a four-cycle engine, the carburetor C is connected to the cylinder head H as shown in FIG. Although not shown in detail, there is also a type in which a carburetor is arranged beside a cylinder block and connected to a cylinder head via a manifold.

[0005]

By the way, small outboard motors are often constructed so that the operator can directly operate the operating system (throttle and choke) of the carburetor from outside the front cover of the outboard motor. In the case of an outboard motor equipped with a two-stroke engine, the carburetor is located in front of the outboard motor,
The operating levers provided on the carburetor project directly outside the cover on the front side of the outboard motor.

However, in the case of an outboard motor equipped with a four-stroke engine, since the carburetor is disposed behind the outboard motor, it is complicated to protrude the operating levers out of the front cover of the outboard motor. A cable mechanism and a link mechanism are required, which causes problems such as a complicated structure and an increase in cost.

Further, as shown in FIG. 6, if the carburetor is arranged beside the cylinder head without using the manifold, there arises a problem that the entire width of the engine becomes large.

The present invention has been made in consideration of the above circumstances, and has as its object to provide an outboard motor with a simplified structure, a compact engine, and reduced cost.

[0009]

An outboard motor according to the present invention comprises:
According to an aspect of the present invention, there is provided an outboard motor in which a crankshaft is vertically arranged in an engine, the engine includes a cylinder head having an intake port, and the cylinder head includes: Is arranged on the bow side of the outboard motor, and a carburetor is connected to the cylinder head, while a drive shaft connected to the crankshaft is offset to the bow side from the crankshaft.

According to another aspect of the present invention, there is provided an outboard motor in which a crankshaft is vertically arranged in an engine.
V type, having a cylinder head equipped with intake / exhaust ports and intake / exhaust valves for opening / closing these ports, and separating a plurality of push rods for opening / closing the intake / exhaust valves below the engine. And an exhaust port passing through the cylinder head is arranged so as to pass between the plurality of push rods.

Further, in order to solve the above-mentioned problems,
According to a third aspect of the present invention, the carburetor is directly attached to the cylinder head having the intake port.

[0012]

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 the top, and a vertical (vertical) engine 3 is housed therein. A steering handle 4 extends forward from a front portion (a bow side, right side in the figure) of the engine cover 2.

A shaft housing 5 is provided below the engine cover 2.
The gear case 6 is provided at the lower part of the vehicle. A propeller shaft 7 is rotatably supported inside the gear case 6, and a propeller 8 is provided at a rear end thereof.

FIG. 2 is an enlarged longitudinal sectional view of the engine 3 of the outboard motor 1, and FIG. 3 is a sectional view taken along the line III-III of FIG. As shown in FIGS. 1 and 2, a crankshaft 9 is provided vertically (vertically) in the engine 3 so as to face a substantially vertical direction.

In the shaft housing 5, a drive shaft 11 connected to a crankshaft 9 via a camshaft 10 to be described later is arranged offset to the front side (bow side, right side in the figure) of the crankshaft 9 and directed downward. And the lower end of the drive shaft 11 is connected to the propeller shaft 7 via the bevel gear 12.
The output of the engine 3 is transmitted to the propeller shaft 7 via the drive shaft 11 and the bevel gear 12, and rotates the propeller 8.

The upper portion of the shaft housing 5 is rotatably supported by a rotation support portion of a clamp bracket 13, and the clamp bracket 13 is fixed to a transom of a ship (not shown). That is, the outboard motor 1 is rotatable about 360 ° with respect to the boat, and the steering of the boat can be performed by swinging the steering handle 4 in the horizontal direction to change the direction of the entire outboard motor 1. It is configured as follows.

The engine cover 2 is, for example, vertically splittable, and comprises a lower cover 2a fixed to a lower portion of the engine 3, and an upper cover 2b detachably mounted on the lower cover 2a. . A front panel 2c is formed on the front side (bow side) of the upper cover 2b. The steering handle 4 is provided integrally with the lower cover 2a.

On the other hand, the engine 3 used in this embodiment
Is a single-cylinder engine of, for example, a four-cycle OHV type. As shown in FIGS. 2 and 3, the engine housing 14 is divided into two parts in the front-rear direction (left-right direction in FIGS. , Left side in FIG. 2)
And a cylinder block 16 on the front side (bow side, right side in FIG. 2) are joined by a mating surface parallel to the axis of the crankshaft 9. And
The engine housing 14 includes the shaft housing 5
Is mounted via an oil pan 17 on an extension part 5a provided at the upper end of the head.

The cylinder block 16 is moved forward (toward the bow, right side in FIG. 2) of the crankshaft 9.
The cylinder head 18 is connected to the front of the cylinder 18 (bow side, right side in FIG. 2). A front opening of a valve operating chamber 20 formed in the cylinder head 19 is closed by a head cover 21. Further, a fuel tank 22 is disposed above the cylinder block 16 and the cylinder head 19.

The crankshaft 9 is supported at a substantially intermediate portion by a pair of bearings 23, in this embodiment, ball bearings. A pair of webs 24 are formed on the crankshaft 9 between the two bearings 23 so as to be separated from each other in the axial direction, and a crankpin 25 is eccentrically provided therebetween.

On the other hand, a cylinder bore 18a is formed inside the cylinder 18, and a combustion chamber 26 matching the cylinder bore 18a is formed in the cylinder head 19. The ignition plug 27 is inserted into the combustion chamber 26 from outside.
Are combined.

A piston 28 is slidably inserted into the cylinder bore 18a. The piston pin 29 of the piston 28 and the crank pin 25 of the crankshaft 9 are connected by a connecting rod 30, whereby the reciprocating motion of the piston 28 in the cylinder bore 18 a is converted into the rotational motion of the crankshaft 9. At the upper end of the crankshaft 9, for example, a flywheel 31 and a rope-recoil type engine starting device 32 are provided.

In the cylinder head 19, an intake port 33 and an exhaust port 34 connected to the combustion chamber 26 are formed.
In the cylinder head 19, an intake valve 35 and an exhaust valve 36 for opening and closing the ports 33 and 34 are arranged substantially horizontally and horizontally side by side.

A carburetor 37 is arranged at the front upper part of the cylinder head 19, and the carburetor 37 is directly attached to the cylinder head 19 and connected to the intake port 33. The carburetor 37 includes a throttle lever 38 and an operation lever of the carburetor 37 and a choke lever 3.
These levers protrude out of the engine cover 2 from the front panel 2c, and as shown in FIG. 4, which is a view taken in the direction of arrow IV in FIG. By moving the carburetor 37 up and down, the carburetor 37 can be operated.

On the other hand, as shown in FIG. 2, a camshaft 10 is connected to an upper end of the drive shaft 11, and the camshaft 10 is arranged in parallel with the crankshaft 9. A timing drive gear 41 is integrally or integrally provided at a lower end of the crankshaft 9, and a timing driven gear 42 is provided on the camshaft 10.
Are provided integrally or integrally with each other.
The rotational force of the crankshaft 9 is transmitted to the camshaft 10 by the engagement of the first and second gears 42.

The engine 3 of the outboard motor 1 shown in this embodiment is of the four-cycle OHV type as described above, and operates to open and close the intake valve 35 and the exhaust valve 36 via the push rod 43. Specifically, a cam 44 is provided on the camshaft 10 and the camshaft 1
The rotation of 0 causes the profile of the cam 44 to move, for example, to a plurality of push rods 43 (for intake and exhaust) left and right in this embodiment, which are arranged horizontally apart from each other at the bottom of the cylinder block 16. The rocker arm 45 provided in the valve chamber 20 of the cylinder head 19 is caused to swing in the axial direction. The rocking arm 45 swings the intake valve 35 and the exhaust valve 36 in the cylinder head 19 to open and close.

As shown in FIG. 2, the exhaust port 34 extends downward in the cylinder head 19 and opens to the extension portion 5a to transmit exhaust gas to the outside of the outboard motor 1 via the shaft housing 5 (underwater). Is configured to be discharged to Further, the exhaust port 34 is disposed so as to pass between two push rods 43 that are separated from each other.

Next, the operation of the present embodiment will be described.

The cylinder head 19 constituting the engine 3
The carburetor 37 is inevitably arranged on the bow side by arranging the carburetor 37 on the bow side contrary to the conventional case. As a result, operation levers such as the throttle lever 38 and the choke lever 39 provided on the carburetor 37 can be directly protruded out of the front panel 2c in front of the outboard motor 1, and the carburetor 37 is disposed on the stern side. In such a case, a complicated cable mechanism or link mechanism for operating the levers, which is necessary in the case, is not required, so that the structure can be simplified and the cost can be significantly reduced.

By the way, when the cylinder head 19 is arranged on the bow side opposite to the conventional one, the crankshaft 9 moves to the stern side, and the drive shaft 11 directly connected to the conventional crankshaft 9 also moves to the stern side. Although a problem arises, in the present invention, the drive shaft 11 is arranged offset (front side) from the crankshaft 9 and the two shafts are connected by the camshaft 10 in the present embodiment. No change.

In addition, in the present invention, the exhaust port 34 passes between the two push rods 43 which are separated to the left and right in the present invention. , The exhaust port 34 is connected to the cylinder head 1
9, the connection to the shaft housing 5 is facilitated.

Further, the carburetor 37 is connected to the intake port 33.
By directly attaching to the cylinder head 19 formed with the above, the manifold which is conventionally required becomes unnecessary, and the weight and cost can be reduced. Further, if the carburetor 37 is arranged at the front upper portion of the cylinder head 19, the entire width of the engine 3 does not increase, and the size of the engine 3 is reduced.

In the above-described embodiment, the carburetor 37 is arranged at the front upper portion of the cylinder head 19 to reduce the size of the engine 3. For example, FIG.
When the center axis EL of the engine 3 is swung by a predetermined angle θ in a horizontal plane from the center axis CL of the outboard motor 1 around the axis of the camshaft 10, for example, the carburetor 37 is moved to the side of the cylinder head 19. Even if it arrange | positions, the compactness of the engine 3 will not be prevented.

[0035]

As described above, according to the outboard motor of the present invention, in an outboard motor in which a crankshaft is vertically disposed in an engine, the engine has a cylinder head having an intake port. The cylinder head is arranged on the bow side of the outboard motor, and the carburetor is connected to the cylinder head, while the drive shaft connected to the crankshaft is offset to the bow side from the crankshaft. Simplification and cost reduction can be achieved.

In an outboard motor in which a crankshaft is vertically arranged in an engine, the engine is an OHV type, and an intake / exhaust port and an intake / exhaust port for opening and closing these ports.
A cylinder head having an exhaust valve, and a plurality of push rods for opening and closing the intake and exhaust valves are arranged at a lower portion of the engine, and the plurality of exhaust ports passing through the cylinder head are provided. Are arranged so as to pass between the push rods, so that the exhaust port can be easily connected to the shaft housing.

Further, since the carburetor is directly attached to the cylinder head having the intake port, no manifold is required, and the engine can be made compact and the weight and cost can be reduced.

[Brief description of the drawings]

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

FIG. 2 is an enlarged longitudinal sectional view of an engine portion of the outboard motor.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a view taken in the direction of an arrow IV in FIG. 2;

FIG. 5 is a plan sectional view of an outboard motor showing a second embodiment of the present invention.

FIG. 6 is a plan sectional view of a conventional outboard motor.

[Explanation of symbols]

 Reference Signs List 1 outboard motor 2 engine cover 2c front panel 3 engine 9 crankshaft 10 camshaft 11 drive shaft 15 crankcase 16 cylinder block 19 cylinder head 33 intake port 34 exhaust port 35 intake valve 36 exhaust valve 37 carburetor 43 push rod

Claims (3)

[Claims] 1. An outboard motor having a crankshaft vertically arranged in an engine, wherein the engine 3 is provided with an intake port 3
3 is provided on the bow side of the outboard motor 1, and a carburetor 37 is connected to the cylinder head 19 while a drive connected to the crankshaft 9 is provided. An outboard motor characterized in that the shaft 11 is offset from the crankshaft 9 on the bow side. 2. In an outboard motor in which a crankshaft is vertically arranged in an engine, the engine 3 is of an OHV type and includes intake / exhaust ports 33, 34 and intake / exhaust valves 35, 36 for opening and closing these ports. A plurality of push rods 43 for opening and closing the intake / exhaust valves 35 and 36 are disposed separately below the engine 3, and an exhaust port 34 passing through the cylinder head 19 is provided. Is arranged so as to pass between the plurality of push rods 43. 3. The outboard motor according to claim 1, wherein the carburetor is directly mounted on the cylinder head provided with the intake port.