JPH10317935A - Oil seal retaining structure for outboard engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily assemble an oil seal retaining structure for an outboard engine with no increase in the number of its component parts without needing a mounting labor. SOLUTION: An outboard engine is formed on the side of a crankcase part 17 in its cylinder block 1 nearer to a flywheel 16 with a bearing boss part 22 for a crankshaft 13, into which boss part a shaft sealing oil seal 32 is fitted, and with a breather chamber 3 next to the boss part 22, which chamber is closed with a detachable breather cover 30. The circumferential part of the cover 30 extends to cover at least part of the seal 32, which extension 38 prevents the seal 32 from being slipped off.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil seal holding structure for a crankshaft bearing of an outboard motor.

[0002]

2. Description of the Related Art Conventionally, an outboard motor has been removably attached to a stern of a small boat as a propulsion device. The crankshaft support of the engine of the outboard motor is sealed by arranging an oil seal at a boss formed on the crankcase of the cylinder body.

[0003]

In the above-mentioned outboard motor, the attitude of the oil seal does not come off due to so-called tilt-up in order to raise the lower propeller above the water when the outboard motor is mounted on the hull. The provision of the retaining means is performed as described above. As the retaining means, a washer or the like is attached to the boss portion for the crankshaft bearing on the flywheel side of the crankshaft.

[0004] However, such a structure has a problem that the number of parts increases and it takes time to mount the parts.

The present invention has been made to solve such a conventional problem, and provides an oil seal holding structure for an outboard motor which does not increase the number of parts and does not require installation. is there.

[0006]

According to the present invention, a boss portion for a crankshaft bearing is formed on a flywheel side of a crankcase portion of a cylinder body of an outboard motor, and an oil seal for a shaft seal is provided on the boss portion. And
A breather chamber is formed adjacent to the boss portion, the breather chamber includes a removable breather cover, and a peripheral portion of the breather cover is formed to extend so as to cover at least a part of the oil seal. The oil seal is prevented from coming off by an extension.

[0007] The crankshaft bearing boss includes:
A configuration may be employed in which a bearing for rotatably supporting the crankshaft is disposed inside the oil seal, and the oil seal is disposed outside the bearing.

In the above construction, since the breather cover also serves as a stopper for the oil seal, no special parts are required for retaining the oil seal, and no trouble is required for mounting the parts. The operation is also simple because the retaining is performed at the same time.

[0009]

1 is a plan view of the upper structure of an outboard motor 100, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is a side view of the outboard motor 100 mounted on a hull. FIG. The outboard motor 100 has an upper cowling 91 and a lower cowling 9.
An upper structure such as an engine is housed in a cowling 9 composed of an upper casing 93, an upper casing 93 and a lower casing 94 are sequentially connected to a lower side of a lower cowling 92, and a drive shaft connected to a crankshaft of the engine is connected to an upper casing. 93 and a lower casing 94, the propeller 95
It is connected to. A bracket 99 is provided on the upper casing 93, and a clamp bracket 96 is attached to a tip end of the bracket 99 via a tilt shaft 97.
The clamp bracket 96 is attached to the upper end of the transom 101 of the hull, and is fixed by being clamped by the clamp handle 98.
In this state, the outboard motor 100 can be raised (tilted up) on the water surface by rotating the outboard motor 100 around the tilt axis 97, and is provided so as to protrude forward from a side portion of the cowling 9. The steering handle 90 allows the outboard motor 100 to be rotated (steered) about a vertical axis (not shown).

As shown in FIG. 1, a cylinder head 1 is provided on the rear side (right side in FIG. 1) of a cylinder body 1 of the engine.
1, a cylinder head cover 12 is connected to the rear side, a fuel tank is arranged on the front side of the cylinder body 1, and an oil pan is formed below the cylinder body 1 integrally with the crankcase portion. . A fuel pump 41 is arranged on the side of the cylinder body 1, and a carburetor (not shown) is arranged above the cylinder head 11.

As shown in FIG. 2, the engine cylinder body 1 installed in the cowling 9 is installed such that the crankshaft 13 is oriented vertically, and the rotational torque of the crankshaft 13 extends downward. The power is transmitted to a horizontally mounted propeller shaft at the lower end of the outboard motor 100 via a drive shaft (not shown) to rotate the propeller. The crankcase part 17 is formed integrally with the cylinder body 1, and a piston 15 is disposed in the cylinder.
The crankshaft 13 connected by the crankcase 2
It is arranged to extend in the up-down direction. On the flywheel side (upper side) of the crankcase part 17, a bearing boss part 22 of the crankshaft 13 is formed. One end of the crankshaft 13 extends upward through the boss part 22, and the projection part is formed. Flywheel 16 at
Is installed. A bearing 21 that rotatably supports the crankshaft 13 is disposed inside (lower) inside the boss portion 22, and an oil seal 32 is disposed outside (upper). The sealing of the penetrating portion is performed.

The breather chamber 3 is formed in the crankcase 17 adjacent to the boss 22. The breather chamber 3 communicates with the crank chamber 2 via a communication passage 35, and the communication passage 35 is provided with a check valve 31. Outside the breather chamber 3, a breather cover 30 is detachably attached to the crankcase 17 with bolts 39 to seal the breather chamber 3, and the peripheral edge of the breather cover 30 is extended to form an extension 38. Have been. The upper portion of the oil seal 32 is covered by the extension portion 38, and the oil seal 32 is prevented from coming off by the extension portion 38. In the illustrated example, the peripheral portion 38 of the breather cover 30 is covered by about half in the diameter direction of the oil seal 32 and about 1/3 in the circumferential direction. May be arbitrarily set as long as is an amount that can be prevented.

In order to assemble the above structure, first, the bearing 21 is press-fitted into the boss portion 22 of the cylinder body 1 from the inside (lower side), and the oil seal 32 is press-fitted from the outside (upper side). A piston 15 with a connecting rod 14 connected thereto is inserted into the cylinder, and a crankshaft 13 to which the connecting rod 14 is not connected is inserted upward from the lower side of the crank chamber 2. The bearing 21 and the oil seal 32 are externally fitted to the crankshaft 13 as shown in FIG. The connecting rod 14 is connected to the crankpin 130.
That is, the connecting rod 14 is constituted by two divided pieces of the crank pin 130 divided in the diameter direction, and the two divided pieces are joined from outside of the link pin 130 so as to be sandwiched therebetween. In the breather chamber 3, a check valve 31 is attached to the communication passage 35. Next, the breather chamber 3 is sealed by fixing the breather cover 30 at a predetermined position with bolts 39.

Next, the flywheel 16 of the crankshaft 13 is fitted into the tip of the crankshaft 13 projecting above the oil seal 32 (upward in FIG. 2), and is secured by a washer 131 and a nut 132 so as not to come off.

The attachment of the breather cover 30 causes the extension 38 to cover the upper portion of the oil seal 32. Therefore, the oil seal 32 is changed by the rotation of the crankshaft 13 or the posture change by tilting up of the outboard motor 100. Even if the oil seal 32 is displaced upward (moves upward) in the boss portion 22, the oil seal 32 is prevented from coming off by hitting the extension portion 38. In addition, since the disengagement prevention means is formed by attaching the breather cover 30 for the breather chamber 3, no special parts are required for preventing the disengagement, and no labor is required for attaching it.

[0016]

As described above, according to the present invention, since the breather cover also serves as a stopper for the oil seal, no special parts are required for retaining the oil seal, and the labor for mounting the parts is eliminated. Is not required, and the attachment of the breather cover prevents the removal at the same time.
The work is also easy.

[Brief description of the drawings]

FIG. 1 is a plan layout view of an upper structure of an outboard motor showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a side view showing a state where the outboard motor is attached to a hull.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder body 2 Crankcase 3 Breather chamber 9 Cowling 13 Crankshaft 14 Connecting rod 15 Piston 16 Flywheel 17 Crankcase part 21 Bearing 22 Bearing boss part 30 Breather cover 31 Check valve 32 Oil seal 35 Communication passage 38 Extension of breather cover Part 100 Outboard motor

Claims (2)

[Claims] 1. A boss portion for a crankshaft bearing is formed on a flywheel side of a crankcase portion of a cylinder body of an outboard motor, and an oil seal for a shaft seal is provided on the boss portion. The breather chamber is provided with a removable breather cover, and a peripheral portion of the breather cover is formed to extend so as to cover at least a part of the oil seal. An oil seal holding structure for an outboard motor, wherein the oil seal is retained. 2. The crankshaft bearing boss portion, wherein a bearing for rotatably supporting the crankshaft is disposed inside the boss portion for the crankshaft, and the oil seal is disposed outside the boss portion. Outboard motor oil seal retention structure.