JP2000027947A - Balancer device for outboard motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a balancer device for an outboard motor to reduce the size of the outboard motor and improve assembly ability. SOLUTION: A crank chamber 10 is formed at a joint between a crankcase 6 and a cylinder block 5 having a cylinder 8 and a crank shaft 12 is arranged at a joint 11 between the crank case 6 in the crank chamber 10 and a the cylinder block 5. In a so formed outboard motor 1, the joint 11 is extended orthogonally to the axial direction of the cylinder 8 and a balancer device 37 is constituted that a balancer weight is fixed on a balancer shaft 39. The balancer shaft 39 is arranged on the joint 11 between the crankcase 6 and the cylinder block 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a balancer device for an outboard motor.

[0002]

2. Description of the Related Art In an engine, primary vibration is easily generated due to reciprocation of a piston. Therefore, some engines include a balancer device for removing the primary vibration.

[0003] A balancer device is constituted by fixing a balancer weight corresponding to the total mass of, for example, a piston and a connecting rod to a balancer shaft. Was.

As an example of the arrangement of the balancer device, there is, for example, an arrangement in which a balancer shaft is arranged on the opposite side of a piston with respect to a crankshaft.

[0005]

However, since an outboard motor generally has a vertically arranged crankshaft, providing a balancer shaft on the opposite side of the piston increases the engine length, and the outboard motor has It becomes large.
In addition, the balancer shaft is not easily assembled.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a balancer device for an outboard motor in which the size of the outboard motor is reduced and the assemblability is improved. .

According to a first aspect of the present invention, there is provided a balancer apparatus for an outboard motor, comprising: a crankcase; a cylinder block having a cylinder; In an outboard motor in which a crankcase is formed in a joint portion of the outboard motor and a crankshaft is arranged on a joint surface between the crankcase and the cylinder block in the crankcase, the joint surface is orthogonal to the axial direction of the cylinder, The balancer device has a structure in which a balancer weight is fixed to a balancer shaft, and the balancer shaft is arranged on a joint surface between the crankcase and the cylinder block.

According to another aspect of the present invention, a balancer driven gear is provided at an end of the balancer shaft, and a balancer drive gear is provided at the crankshaft. And a balancer drive gear disposed in the crank chamber.

Further, in order to solve the above-mentioned problems,
As described in claim 3, the balancer driven gear is provided with a shock absorber.

[0009]

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

FIG. 1 is a left side view of an outboard motor to which the present invention is applied, and FIG. 2 is a longitudinal sectional view of an upper half of the outboard motor. As shown in FIGS. 1 and 2, the outboard motor 1 includes an oil pan 2 also serving as an engine holder, and an engine 3 is installed above the oil pan 2.

The engine 3 is, for example, a water-cooled four-cycle two-cylinder engine, and is constructed by combining a cylinder head 4, a cylinder block 5, a crankcase 6, and the like, and is mounted on the oil pan 2 via a cam chain case 7. Is done.

A cylinder block 5 is arranged behind a crankcase 6 arranged at the forefront of the engine 3, that is, on the right side in FIG. The cylinder head 4 is arranged behind the cylinder block 5. Further, a cam chain case 7 is arranged below the crankcase 6, the cylinder block 5, and the cylinder head 4.

FIG. 3 is a sectional view taken along the line III-III of FIG. As shown in FIGS. 2 and 3, the engine 3
A cylinder 8 is formed substantially horizontally in the cylinder block 5, and a piston 9 is slidably inserted in the cylinder 8 in the axial direction of the cylinder 8. On the other hand, the crankcase 6 and the cylinder block 5 have a crank chamber 10
And these joining surfaces 11 are formed orthogonal to the axial direction of the cylinder 8. The crankshaft 12 is disposed substantially vertically on the joint surface 11 of the crankcase 6 and the cylinder block 5 in the crank chamber 10. Further, the crankshaft 12 and the piston 9 are connected by a connecting rod 13 so that a reciprocating stroke of the piston 9 is converted into a rotational motion of the crankshaft 12.

As shown in FIG. 1, a shaft housing 14 is provided below the oil pan 2. The lower end of the crankshaft 12 is connected to the upper end of the drive shaft 15. A drive shaft 15 extends downward in the shaft housing 14, and is configured to drive a propeller 19 via a bevel gear 17 and a propeller shaft 18 in a gear case 16 provided at a lower portion of the shaft housing 14.

A combustion chamber 20 matching the cylinder 8 is formed in the cylinder head 4 of the engine 3, and a spark plug 21 is connected from the outside thereof. Further, an intake port 22 and an exhaust port 2 connected to the combustion chamber 20 are provided in the cylinder head 4.
3 are also formed. Further, an intake valve 24 and an exhaust valve 25 for opening and closing both ports 22 and 23 are arranged in the cylinder head 4, and a cam shaft 26 for opening and closing these valves 24 and 25 is provided at the rear of the cylinder head 4. Be placed. The cylinder head 4 is covered by the head cover 27.

As shown in FIG. 2, the upper end of the crankshaft 12 projects above the engine 3. A flywheel magneto device 28 for power generation is provided on this protrusion, and the engine 3
A ring gear 31 is formed which is operatively connected to a starter motor 30 disposed in front of the ring gear 31.

On the other hand, a camshaft drive mechanism 32 for transmitting the rotation of the crankshaft 12 to the camshaft 26 and driving the camshaft 26 to rotate is provided in the cam chain case 7 below the engine 3. The camshaft drive mechanism 32 is, for example, a chain drive system, and includes a cam drive sprocket 34 provided on a connecting member 33 that connects the crankshaft 12 and the drive shaft 15 projecting from the lower surface of the engine 3, and the engine 3. A cam-driven sprocket 35 provided integrally with the lower end of the camshaft 26 projecting from the lower surface of the camshaft 26;
And a timing chain 36 wound around these sprockets 34, 35.

Since the engine 3 is liable to generate a primary vibration based on the reciprocating motion of the piston 9, a balancer device 37 for removing the primary vibration is provided.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 3, and FIG. 5 is a sectional view taken along line VV of FIG.
As shown in FIG. 4, the balancer device 37 is configured by fixing a balancer weight 38 corresponding to the total mass of, for example, the piston 9 and the connecting rod 13 to a balancer shaft 39.
The engine 3 is configured to remove vibrations during operation of the engine 3 by interlocking rotation.

The balancer shaft 39 is connected to the crank chamber 10
Is arranged in parallel with the crankshaft 12 on the joint surface 11 between the crankcase 6 and the cylinder block 5. A balancer driven gear 40 is provided at the end of the balancer shaft 39.
And meshes with a balancer drive gear 41 provided on the crankshaft 12. The balancer driven gear 40 and the balancer drive gear 41 are arranged in the crank chamber 10.

As shown in FIGS. 4 and 5, the balancer driven gear 40 is divided into a concentric outer race 42 and an inner race 43 in order to prevent gear damage due to torque fluctuations of the engine 3. , 43
A plurality of springs 4 constituting a shock absorber are provided on the contact surface of
4 are arranged. Further, a pin 45 for preventing the spring 44 from falling off is provided in the spring 44, and a washer plate 46 for preventing the spring from falling off is provided on both side surfaces of the balancer driven gear 40.

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

If the balancer shaft 39 constituting the balancer device 37 is disposed on the joint surface 11 between the crankcase 6 and the cylinder block 5, the balancer shaft 39 can be assembled simultaneously when the crankshaft 12 is assembled. Stickiness is improved.

Further, if the joint surface 11 of the crankcase 6 and the cylinder block 5 is formed so as to be orthogonal to the axial direction of the cylinder 8, even if the balancer shaft 39 is disposed on the joint surface 11, the length of the engine 3 itself is reduced. Since the size does not change, the outboard motor 1 does not increase in size. The joining surface 11 between the crankcase 6 and the cylinder block 5 does not necessarily need to be orthogonal to the axial direction of the cylinder 8, but the shorter the angle formed between them, the shorter the length of the engine 3 can be.

Further, if both the gears 40, 41 of the balancer driven gear 40 and the balancer drive gear 41 are arranged in the crank chamber 10, the gears 40, 41 can be lubricated without providing a special path.

Further, the provision of the buffering device 44 in the balancer driven gear 40 can prevent the gears 40 and 41 from being damaged due to the torque fluctuation of the engine 3.

[0027]

As described above, according to the outboard motor balancer apparatus according to the present invention, a crank chamber is formed in a joint between a crankcase and a cylinder block having a cylinder, and the crank chamber is formed in the crank chamber. In an outboard motor in which a crankshaft is arranged on a joint surface between the crankcase and the cylinder block, the joint surface is orthogonal to the axial direction of the cylinder, and the balancer device is configured by fixing a balancer weight to a balancer shaft. Since the balancer shaft is arranged at the joint surface between the crankcase and the cylinder block, the outboard motor can be made compact and the assemblability of the balancer device can be improved.

Also, a balancer driven gear is provided at the end of the balancer shaft, and a balancer drive gear is provided on the crankshaft. These balancer driven gear and balancer drive gear are disposed in the crank chamber, so that both gears can be easily lubricated. Can be.

Further, since the balancer driven gear is provided with a shock absorber, it is possible to prevent the gear from being damaged due to engine torque fluctuation.

[Brief description of the drawings]

FIG. 1 is a left side view of an outboard motor showing one embodiment of a balancer device for an outboard motor according to the present invention.

FIG. 2 is a longitudinal sectional view of an upper half of the outboard motor.

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. 3;

FIG. 5 is a sectional view taken along the line VV in FIG. 4;

[Description of Signs] 1 Outboard motor 3 Engine 5 Cylinder block 6 Crankcase 8 Cylinder 10 Crankcase 11 Joint surface between crankcase and cylinder block 12 Crankshaft 37 Balancer device 38 Balancer weight 39 Balancer shaft 40 Balancer driven gear 41 Balancer drive Gear 44 Spring (buffer)

Claims (3)

[Claims] 1. An outboard motor in which a crank chamber is formed in a joint between a crankcase and a cylinder block having a cylinder, and a crankshaft is arranged on a joint surface between the crankcase and the cylinder block in the crank chamber. In the above, the joining surface 11 is made orthogonal to the axial direction of the cylinder 8, and the balancer device 37 is configured by fixing a balancer weight 38 to a balancer shaft 39, and the balancer shaft 39 is connected to the crankcase 6 and the cylinder block 5. A balancer device for an outboard motor, wherein the balancer device is disposed on the joint surface 11 of the outboard motor. 2. A balancer driven gear 40 is provided at an end of the balancer shaft 39, and a balancer drive gear 41 is provided on the crankshaft 12. The balancer driven gear 40 and the balancer drive gear 41 are disposed in the crank chamber 10. The balancer device for an outboard motor according to claim 1. 3. The balancer device for an outboard motor according to claim 2, wherein a buffer device is provided on said balancer driven gear.