JP2593057B2 - Outboard motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outboard motor, and more particularly to an outboard motor equipped with a high-power engine.

[0002]

2. Description of the Related Art In recent years, outboard motors have been desired to have higher output, and as a result of larger displacements, engines tend to be larger. However, in practice, excessive enlargement of the engine is not preferable, and an engine that can be configured as compact as possible is desired.

On the other hand, in order to simplify the overall structure, it is effective to arrange the crankshaft vertically in the engine for an outboard motor, and an outboard motor equipped with such a vertical crankshaft engine is effective. And Japanese Utility Model Publication No. 47-27113.

However, the engine disclosed in the publication has a configuration in which two cylinders are arranged in series along a crankshaft, and thus it is difficult to reduce the height.

[0005] In this regard, in the case of a vertical-axis V-type engine disclosed in Japanese Patent Application Laid-Open No. 61-81572, two cylinders adjacent in the crankshaft direction are opened in a V-shape to reduce the height dimension. The advantage of obtaining is obtained.

[0006]

However, on the other hand, this V-type engine has an intake pipe connected to its upper surface, and is configured so that fresh air flows downward into the carburetor. There is a drawback that when splashed during navigation, water easily enters during intake.

[0007] The present invention has been devised to solve such disadvantages of the prior art, and its main objects are as follows.
An object of the present invention is to provide an outboard motor including a high-power engine that is compact and has an engine configured to make it difficult for water to enter during intake.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a crankshaft extending in a substantially vertical direction, and a pair of oppositely disposed V-shaped expanding and centering crankshafts. An engine body including a bank, at least a part of which is covered by a cowling, a propeller driven by the engine body, an extension case covering a coupling mechanism between the engine body and the propeller, the cowling, the engine body, An outboard motor having a propeller, and a clamp device for fixing the entirety of the extension case to a hull, wherein the outboard motor communicates with an intake port inside the pair of banks, and extends from the crankshaft in a substantially horizontal plane. An intake passage extending in a direction away from the intake passage; a throttle valve device connected upstream of the intake passage; Is the connection to the intake upstream end of the opening and transverse connecting ports a with the throttle valve device is achieved by providing a outboard motor and having a guide cover to produce an upward air flow.

[0009]

According to this structure, since the throttle valve device is disposed inside the V bank, the intake system can be made compact while securing a required intake pipe length. Further, even if the cowling is exposed to water, since the intake port of the throttle valve device is covered with the guide cover, it is possible to prevent water from entering the intake path.

In particular, when the throttle valve device is provided with one intake path corresponding to one cylinder and is paired with cylinders defined in banks facing each other, a high intake efficiency with a compact structure is obtained. Can be obtained. When two or more cylinders are provided for each bank, the throttle valve devices are arranged vertically in the crankshaft direction, and a connection port with each throttle valve device is provided on the guide cover. And the waterproofness can be further improved without increasing the number of parts. Furthermore, if the throttle valve device is provided with a throttle valve shaft extending in a substantially horizontal direction across the center line of the bank included angle and a lever member for transmitting operating force provided on the side, the compact arrangement is further improved. Can be highly propelled.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 shows an entire outboard motor equipped with an engine according to the present invention. Engine body 1 in the figure
Is configured as a vertical crankshaft engine in which a pair of banks 2a and 2b each having three cylinders installed therein are arranged in a V-shape facing each other, and a crankshaft 3 is arranged in a substantially vertical direction. . And both banks 2a
A carburetor unit 4 as a throttle valve device is disposed between 2b.

A vertical shaft 5 is connected to a lower end of the crankshaft 3. A bevel gear device 6 and a propeller shaft 7 mounted on the shaft end of the vertical shaft 5 are provided.
The rotational force is transmitted to the propeller 8 via.

A water pump 9 is provided below the vertical shaft 5 to supply cooling water pumped from the water to the inside of the engine via a water pipe 9a to cool each part of the engine body 1. Have been to be. The cooling water circulated inside the engine passes through a drain passage provided in the exhaust pipe 10 and is discharged together with the exhaust gas into a passage that also functions as an expansion chamber formed inside the extension case E, and is discharged from the outboard motor. It is discharged into water from alongside.

The outboard motor can be fixed to a hull (not shown) by a clamp device 11, and the engine body 1 is covered by a detachable cowling 12.

FIGS. 2 and 3 partially show the engine body 1 shown in FIG. 1 in detail. The engine body 1 has a pair of banks 2a and 2b arranged in a V-shape with an angle of 45 °.
Since 2b has substantially the same structure, only one bank 2a will be mainly described below.

Each of the banks 2a and 2b includes three cylinders 13 in series along the axis of a vertically disposed crankshaft 3 not shown in FIGS. A cylinder block 14 is provided, and a cylinder head 15 is fixed to an end face of the cylinder block 14 in the cylinder axial direction. The open end of the cylinder head 15 is closed by a head cover 16.

A pulley 17 is provided inside the head cover 16.
1 using a belt transmission mechanism consisting of a
Camshaft 1 connected to crankshaft 3 with a speed ratio of 1/2
7 is pivotally supported (FIG. 2), and a pair of cams 18a and 18b provided along the cam shaft 17 are engaged with a pair of rocker arms 19 and 20, respectively. The pair of rocker arms 19 and 20 are pivotably supported by a pair of rocker shafts 19a and 20a, respectively, and tappet screws 19b and 2 screwed to the working ends thereof so as to advance and retreat.
Ob contacts the ends of the intake valve 21 and the exhaust valve 22 via 0b.

The intake valve 21 and the exhaust valve 22 are generally mushroom-shaped, and their stem portions 21a and 22a are
5 are slidably inserted into the valve guides 23 and 24 fitted on the intake port 5 so that the intake ports 25 and the exhaust ports 26 can be opened and closed by the expanded head portions 21b and 22b. At the stem end, a retainer 27
28, respectively, and the retainers 27 and 28
Between the cylinder head 15 and the stem portions 21a and 22a
The two valves 21 and 22 are normally urged in the valve closing direction by the coil springs 29 and 30 interposed surrounding. In addition, the coil springs 29 and 30 are configured so that surging hardly occurs by providing two springs having different natural frequencies.

In this manner, by the rotation of the camshaft 17 synchronized with the crankshaft 3, the two valves 21 and 22 are driven to open and close according to a predetermined timing, and the intake of the mixture into the combustion chamber 31 and the combustion gas Is performed according to each process.

At a position corresponding to each cylinder 13 of the cylinder head 15, an ignition plug 32 is screwed from an oblique side, and an end face of a piston 33 slidably received in the cylinder 13 and a cylinder head 15. The electrode (not shown) protrudes toward the combustion chamber 31 formed between the electrodes.

The piston 33 is connected to the crankshaft 3 via a connecting rod 34 so that the reciprocating motion of the piston 33 caused by the combustion pressure of the fuel can be converted into the rotational motion of the crankshaft 3.

An exhaust manifold 35 defining an exhaust passage communicating with the exhaust port 26 is formed integrally with the cylinder head 15 outside the banks 2a and 2b. The exhaust manifold 35 collects the exhaust gas from the cylinders and guides the exhaust gas to the exhaust pipe 10 shown in FIG. 1. A water jacket 36 for passing cooling water is formed in an outer layer portion of the exhaust manifold 35. This water jacket 36
Is a water jacket 15a of the cylinder head 15,
And water jacket 14a of cylinder block 14
And the cooling water of the engine body 1 is made to flow therethrough. In addition, the exhaust manifold 35 curves the passage 35 a on the side connected to the cylinder head 15 toward the cylinder block 14, and at the same time, the long axis side of the oval cross section of the collective passage 35 b extending in the crankshaft direction,
The exhaust manifolds 35 are formed along the cylinder axis so that the side ends of the exhaust manifolds 35 are located inside rather than the side ends of the head covers 16.

An intake passage communicating with the intake port 25 is defined on the inner surfaces of the banks 2a and 2b opposite to each other, and an intake pipe 37 formed integrally with the cylinder head 15 has an angle between the banks. It extends in a direction orthogonal to the crankshaft 3 along the center line. These two banks 2a
The intake pipe 37 extending from the opening 2b has an axis A at its opening.
1 .A2 are formed so as to be parallel to each other, and the axial end faces 38a of both open ends 38 are coplanar.

The carburetor unit 4 is connected to the two open ends 38 via a joint member 39 also serving as an insulator made of rubber or the like. The joint member 39 is connected to the two open ends 38 and the carburetor unit 4. A pair of bands 4
1 are tightly fastened.

In the carburetor unit 4, a pair of parallel intake passages 42 and 43 are formed in an integrated body 44, and choke valves 45 and 46 are provided upstream of the respective intake passages 42 and 43. The throttle valves 47 and 48 are rotatably supported on the downstream side. The pair of valves 45 to 48 provided in the intake passages 42 and 43 are fixed to a pair of valve shafts 49 and 50 disposed in parallel, respectively. Has a lever member 51
52 is fixedly connected to a choke and throttle operating device using a wire or a link (not shown).

The openings of the intake paths 42 and 43 are
It is covered by an air filter 53 made of a wire mesh or the like, and its outer surface is further protected by an intake inflow guide cover 54 common to all carburetors. The guide cover 54 is connected to the intake passages 42 and 43 laterally and is opened downward, so that even when the cowling 12 is exposed to water, water is supplied to the intake passages 42 and 43 of each carburetor. It is kept out of the way. The main carburetor unit 4
Has a double-chamber single-chamber configuration in which a float chamber 40a for both intake passages 42 and 43 is shared.

The water jackets 15a in the cylinder heads are provided on the end faces of the cylinder heads 15 in the cylinder row direction.
A cooling water outlet pipe 56 communicating with the cooling water is protruded with a flange 55. The outlet pipe 56 is bent in an elbow shape immediately after the flange 55, and then the two banks 2a
b, and extend the terminal to both banks 2a.
2b is fitted into a thermostat chamber 57 disposed at the center of the thermostat chamber 2b. The thermostat chamber 57 is open toward the back side in FIG. 2, and discharges cooling water to the outside through a discharge pipe (not shown) provided along the exhaust pipe 10. .

Both banks 2a and 2 of the cylinder block 14
A breather chamber 58 as an empty space is defined in a substantially triangular space sandwiched between the inner wall surfaces facing each other, and the back pressure in the crankcase due to the reciprocating motion of the piston 33, and the piston 33 and the cylinder The gas blown from the gap with the passage 13 is released through a breather passage 59 penetrated from inside the crankcase. And, between the breather chamber 58 and the breather passage 59,
A valve element 6 having a check valve 60 such as a reed valve, for example.
1 is provided so that the inside of the crankcase is always filled with negative pressure. The lubricating oil separated in the breather chamber 58 is returned into the crankcase through a small-diameter hole 62 drilled at the bottom of the valve body 61.

As described above, in a V-type vertical engine for an outboard motor, the engine height is mainly determined by the entire length of the crankshaft, and the engine width is mainly determined by the bank angle.

However, as shown in the above embodiment, an intake system is provided inside the two banks 2a and 2b, and the intake pipe 37 is remote from the crankshaft 3 along the center line of the bank angle. By extending in the leaving direction, the carburetor unit 4 can be installed without lowering the intake efficiency, despite the reduced angle between the banks.

Further, as shown in the above embodiment, the exhaust system is provided outside the two banks 2a and 2b, and the exhaust passage 35a is curved slightly toward the crankshaft, so that the engine width at the head cover 16 is reduced. The exhaust manifold 35 can be installed without protruding.

[0033]

As described above, according to the present invention, the intake passage extends in the direction away from the crankshaft on a substantially horizontal plane inside the pair of banks, and the throttle valve device is connected upstream of the intake passage. By connecting a guide cover that generates an upward intake air flow to the intake upstream end of the throttle valve device, the intake system of the V-type four-cycle OHC engine is made compact, and water hardly enters into the intake air. It can be. Therefore, a great effect can be achieved in promoting the performance enhancement of the outboard motor without increasing the number of parts or excessively increasing the size.

[Brief description of the drawings]

FIG. 1 is an overall schematic view of an outboard motor equipped with an engine to which the present invention is applied.

FIG. 2 is a plan view showing one embodiment of an engine according to the present invention with a part cut away.

FIG. 3 is a partial longitudinal sectional view of the engine shown in FIG. 2;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine main body, 2a and 2b ... Bank, 3 ... Crank shaft, 4 ... Carburetor unit, 5 ... Vertical shaft, 6
... bevel gear device, 7 ... propeller shaft, 8 ... propeller, 9 ... water pump, 10 ... exhaust pipe, 11 ... clamp device, 12 ... cowling, 13 ... cylinder, 14 ... cylinder block, 15 ... cylinder head, 14a / 15
a ... water jacket, 16 ... head cover, 17 ...
Cam shaft, 17a ... pulley, 17b ... belt, 18a-1
8b: cam, 19/20 ... rocker arm, 19a / 20
a: Rocker shaft, 19b / 20b: Tappet screw,
Reference numeral 21: intake valve, 22: exhaust valve, 21a, 22a: stem portion, 21b, 22b: head portion, 23, 24: valve guide, 25: intake port, 26: exhaust port, 27.2
Reference numeral 8: retainer, 29/30: coil spring, 31: combustion chamber, 32: ignition plug, 33: piston, 34: connecting rod, 35: exhaust manifold, 35a: passage, 35b
... collective passage, 36 ... water jacket, 37 ... intake pipe, 38 ... open end, 38a ... open end face, 39 ... joint member, 41 ... band, 42/43 ... intake path, 44 ... body, 45/46 ... choke valve , 47, 48: throttle valve, 49, 50: valve shaft, 51, 52: lever member,
53 ... air filter, 54 ... guide cover, 55 ... flange, 56 ... outlet pipe, 57 ... thermostat chamber, 58 ...
Breather chamber, 59 ... breather passage, 60 ... check valve, 61 ... valve body, 62 ... small diameter hole

Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display F02M 35/10 F02M 35/10 301V

Claims (4)

(57) [Claims] 1. A crankshaft 3 extending in a substantially vertical direction, and a pair of banks 2a and 2b which are spread out in a V-shape with the crankshaft as a center and are opposed to each other. Engine body 1
A propeller 8 driven by the engine main body, an extension case E covering a coupling mechanism between the engine main body and the propeller, and an entirety of the cowling, the engine main body, the propeller, and the extension case fixed to a hull. An outboard motor having a clamping device 11 of the following, which communicates with an intake port 25 inside the pair of banks,
An intake passage 37 extending in a direction away from the crankshaft on a substantially horizontal plane; a throttle valve device 4 connected upstream of the intake passage; and a downward opening and a lateral connection port. Guide cover 5 connected to the intake upstream end of the device to generate an upward intake flow
4. An outboard motor comprising: 2. The throttle valve device according to claim 1, wherein the throttle valve device includes one intake path corresponding to one cylinder, and the intake paths form a pair corresponding to cylinders facing each other. Outboard motor as described. 3. The engine body includes two or more cylinders in each bank, the throttle valve devices are vertically arranged side by side in a crankshaft direction, and the guide cover has a connection port with each throttle valve device. The outboard motor according to claim 2, comprising: 4. A throttle valve device comprising: a throttle valve shaft extending substantially horizontally across a center line of a bank included angle; and an operating force transmitting lever member 52 provided on a side. The outboard motor according to claim 2, wherein