JPH09177563A - Engine for outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturize an engine by arranging a balancer shaft constituting a balancer device in parallel with a crankshaft arranged roughly vertically on the approximate center line of the engine. SOLUTION: The water cooling 4-cycle 2-cylinder engine 3 of an outboard motor 1 is constructed by the combination of a cylinder head 4, a cylinder block 5, a crankcase 6 and the like and a crankshaft 7 is arranged roughly in a vertical direction in the crankcase 6. A balancer device 24 is arranged in a space 23 formed between a magnet and a shift operation mechanism in the front side of the crankcase 6. This balancer device 24 has one balancer shaft 25, this is supported in parallel with the crankshaft 7 on the approximate center line 28 of the engine 3 by a bearing held by the crankcase 6 and a balancer case 26 and a balancer weight 29 is provided so as to match the total mass of a piston 10, a connecting rod 11 and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an outboard engine, and more particularly to an outboard engine characterized by the position of a balancer device.

[0002]

2. Description of the Related Art An engine is apt to generate a primary vibration due to a reciprocating motion of a piston. Therefore, some engines have a balancer device for removing the primary vibration.

The balancer device is constructed by fixing a balancer weight corresponding to the total mass of a piston, connecting rod, etc., to a balancer shaft, and rotating this balancer shaft in conjunction with a crankshaft to eliminate vibration during engine operation. It was

As an example of equipping the engine of an outboard motor with a balancer device, there are, for example, those disclosed in Japanese Examined Patent Publication No. 7-65639 and Japanese Utility Model Laid-Open No. 64-18998.

[0005]

However, since the balancer device disclosed in Japanese Patent Publication No. 7-65639 is arranged above the vertically arranged crankshaft, the height of the entire engine is increased. Along with
Since this balancer device is a biaxial balancer type having two balancer shafts, there are many problems such as an increase in the number of parts, a complicated structure, and an increase in the size of the balancer case.

In the balancer device disclosed in Japanese Utility Model Laid-Open No. 64-18998, the width of the entire engine is increased because the balancer shaft is arranged on the width direction side of the outboard motor with respect to the crankshaft. I say.

In any of the conventional examples, the outboard motor has been increased in size by equipping the engine with the balancer device.

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 engine which is provided with a balancer device and which can maintain miniaturization of the engine.

[0009]

In order to solve the above-mentioned problems, an outboard motor engine according to the present invention has a crankshaft arranged substantially vertically in a crankcase of the engine as described in claim 1. In the arranged engine for outboard motors, a balancer shaft that constitutes a balancer device is arranged in parallel with the crankshaft on a substantially center line of the engine.

In order to solve the above-mentioned problem, as described in claim 2, the crankshaft is arranged substantially vertically in the crankcase of the engine, and the upper end of the crankshaft protruding above the crankcase is arranged. In the engine for an outboard motor, in which a magnet is arranged so as to project forward from the crankcase, and a shift operation mechanism is arranged in a lower front portion of the crankcase, the magnet and the shift operation mechanism are provided in front of the crankcase. The balancer device is arranged in a space formed between the balancer device and.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical sectional view of an outboard motor to which the present invention is applied. As shown in FIG. 1, the outboard motor 1 includes an engine holder 2, and an engine 3 is installed above the engine holder 2. The engine 3 is, for example, a water-cooled 4-cycle two-cylinder engine, and is configured by combining a cylinder head 4, a cylinder block 5, a crankcase 6, and the like. A crankshaft 7 is arranged substantially vertically in the crankcase 6, while an oil pan 8 is formed in the engine holder 2.

FIG. 2 is an enlarged vertical sectional view of the engine 3. FIG. 3 is a sectional view taken along line III-III of FIG. 2, and FIG. 4 is a sectional view taken along line IV-IV of FIG. Is.
In addition, in FIGS. 1 to 4, the left side of the drawings is the traveling direction of a ship (not shown) on which the outboard motor 1 is mounted, that is, the outboard motor 1
The front side of

As shown in FIGS. 1 to 4, a cylinder block 5 is arranged behind the crankcase 6 of the engine 3, and a cylinder 9 is formed in the cylinder block 5. A piston 10 is slidably inserted into the cylinder 9 in a direction perpendicular to the crankshaft 7, and the piston 10 and the crankshaft 7 are connected by a connecting rod 11. The reciprocating stroke of the piston 10 is converted into the rotational movement of the crankshaft 7.

An upper end portion of the crankshaft 7 projects above the crankcase 6, a magneto 12 is provided at the upper end portion, and a recoil starter 13 is provided above the magneto 12. In addition, a part of the magneto 12 and the recoil starter 13 is arranged so as to project forward from the crankcase 6. Further, the upper end of the drive shaft 14 is spline-fitted to the lower end of the crankshaft 7, for example.

On the other hand, a drive shaft housing 15 is installed below the engine holder 2. A shaft pipe 16 is formed in the drive shaft housing 15, and the drive shaft 14 is formed in the shaft pipe 16.
Drive shaft housing 1
5 through a bevel gear and a propeller shaft (not shown) in a gear case 17 provided at the bottom of the propeller 18
Is configured to drive.

A propeller 18 is provided in the gear case 17.
There is provided a shift mechanism (not shown) for rotating the gears in the forward / reverse direction or in the neutral state. A shift rod 19 for operating this shift mechanism is arranged in front of the drive shaft 14 substantially in parallel with the drive shaft 14 and extends upward. The upper end of the shift rod 19 is located at the lower front of the crankcase 6
0 and shift operating mechanism 22 having shift arm 21
Connected to.

The magneto 1 in front of the crankcase 6
A balancer device 24 is arranged in a space 23 formed between the shift operation mechanism 22 and the shift operation mechanism 22. Balancer device 24
Has a single balancer shaft 25, and the balancer shaft 25 includes a crankcase 6 and a balancer case 26.
A bearing 27 held by means of and supports the engine 3 on a substantially central line 28 in parallel with the crankshaft 7. Further, the balancer shaft 25 is provided with a balancer weight 29 corresponding to the total mass of the piston 10, the connecting rod 11, etc., for example.

A balancer driven gear 30 is provided on the upper end of the balancer shaft 25. A balancer drive gear 31 provided on the crankshaft 7 meshes with the balancer driven gear 30 so as to rotate the balancer shaft 25 in the opposite direction of the crankshaft 7. The balancer drive gear 31 and the balancer driven gear 30 may be operatively connected by a chain, a belt or the like.

By the way, the periphery of the engine holder 2 is covered with a lower cover 32, and the engine 3 installed on the engine holder 2 is covered with an engine cover 33. As shown in FIG. 2, the front lower portion of the engine cover 33 is locked to the front upper portion of the lower cover 32, and the rear lower portion of the engine cover 33 is attached to the rear upper portion of the lower cover 32 by fasteners 34.

Details of the locking portion at the lower front portion of the engine cover 33 indicated by the arrow A in FIG. 2 are shown in FIGS. 5 (A) and 5 (B).

A boss 36 for fixing the locking hook 35 is projectingly provided inside the front upper part of the lower cover 32, and the locking hook 35 is fixed to the boss 36 with a screw 37 or the like. On the other hand, a flange-shaped locked portion 38 is integrally formed with the engine cover 33 so as to project inside the front lower portion of the engine cover 33, and a reinforcing rib 39 is provided on the locked portion 38 above the locked portion 38. Also, it is provided integrally with the engine cover 33. And
By locking the locking hook 35 to the locked portion 38, the lower front portion of the engine cover 33 is locked to the upper front portion of the lower cover 32. The locking hook 35 and the locked portion 3
The arrangement position of 8 may be turned upside down.

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

The space 23 formed in front of the crankcase 6 between the magneto 12 and the shift operating mechanism 22 has been a dead space in the past, but by arranging the balancer device 24 in this space 23, The outboard motor 1 does not increase in size in the height direction, the length direction, the width direction, or the like, and the outboard motor 1 does not increase in size.

Further, since the balancer device 24 is a uniaxial balancer type having one balancer shaft 25, the number of parts is reduced and the structure is simplified as compared with the biaxial balancer type, and the balancer case 26 can be miniaturized. .

[0026]

As described above, according to the engine for an outboard motor of the present invention, the crankshaft is arranged substantially vertically in the crankcase of the engine, and the crankshaft protruding above the crankcase is installed. In an outboard motor engine in which a magnet is arranged at an upper end portion so as to project forward from the crankcase, and a shift operation mechanism is arranged at a lower front portion of the crankcase, the magneto and shift operation in front of the crankcase are performed. The balancer device is arranged in the space formed between the mechanism and
Since the balancer shaft that constitutes this balancer device is arranged substantially parallel to the center line of the engine in parallel with the crankshaft, the balancer device can be arranged by effectively utilizing the dead space without increasing the size of the outboard motor. .

[Brief description of the drawings]

FIG. 1 is a vertical cross-sectional view of an outboard motor showing an embodiment of an outboard engine according to the present invention.

FIG. 2 is an enlarged vertical sectional view of the engine.

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

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 2;

5A is a vertical cross-sectional view showing details of a locking portion at a lower front portion of the engine cover, which is indicated by an arrow A in FIG. 2, and FIG.
FIG.

[Explanation of symbols]

1 Outboard Motor 2 Engine Holder 3 Engine 6 Crank Case 7 Crank Shaft 12 Magneto 14 Drive Shaft 15 Drive Shaft Housing 17 Gear Case 19 Shift Rod (Shift Operating Mechanism) 20 Shift Shaft (Shift Operating Mechanism) 21 Shift Arm (Shift Operating Mechanism) 22 Shift Operation Mechanism 23 Space Formed Between Magnet and Shift Operation Mechanism 24 Balancer Device 25 Balancer Shaft 28 Engine Center Line 29 Balancer Weight 32 Lower Cover 33 Engine Cover 35 Locking Hook 38 Locked Part 39 Locked Part reinforcement rib

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masashi Takayanagi, 300, Takatsuka-cho, Hamamatsu-shi, Shizuoka Prefecture Suzuki Stock Company (72) Inventor, Fumio Matsui, 300, Takatsuka-cho, Hamamatsu-shi, Shizuoka Suzuki Stock Company

Claims (2)

[Claims] 1. An outboard motor engine in which a crankshaft is arranged substantially vertically in a crankcase of the engine.
5. An outboard engine, which is arranged substantially parallel to the center line 28 of the engine 3 in parallel with the crankshaft 7. 2. A crankshaft 7 is disposed substantially vertically in a crankcase 6 of an engine 3, and a magnet 12 is stretched forward from the crankcase 6 at an upper end portion of the crankshaft 7 protruding above the crankcase 6. In the outboard engine having the shift operation mechanism 22 arranged in the lower front part of the crankcase 6, the magnet 1 in front of the crankcase 6 is arranged.
The outboard motor engine according to claim 1, wherein the balancer device 24 is arranged in a space 23 formed between the shift operation mechanism 22 and the shift operation mechanism 22.