JPS62284945A - Cylinder block of outboard motor - Google Patents

Abstract

PURPOSE:To easily form an air vent hole for a cast-off hole after a coating operation is over by forming a small diameter cast-off hole leaving a thin wall on its deep bottom face, on an outer surface corresponding to said cast-off hole, in a cylinder block having a closed cast-off hole for reducing weight. CONSTITUTION:A cast-off hole 5 for reducing weight which is opened to a joining surface is formed on a cylinder block 1 which is joined to a crankcase 2 by means of a bolt 4 via a gasket 3, and a cast-off hole 5b is equally formed on the crankcase 2. And, when the cylinder block 2 is joined to the crankcase 2, a closed vacant space is formed by both the cast holes 5a, 5b. Also, a small diameter cast-off hole 9 which is inwardly recessed leaving a thin wall 8 on its deep bottom face, is formed on the outer surface of a cylinder block wall 7 which separates the cast-off hole 5a from the outer surface 6 of the cylinder block. And, after carrying out coating and surface treating operations, the thin wall 8 is removed by driving a punch 10 into the cast-off hole 9, to form an air vent hole for the cast-off holes 5a, 5b.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Object of the Invention] (Field of Industrial Application) This invention provides an outboard motor whose surface is treated by degreasing, deoxidizing, painting, etc. after assembly. Regarding cylinder blocks.

(Prior Art) Several cast holes are arranged in the aluminum die-cast cylinder block of the engine part incorporated in an outboard motor to reduce waste. This cast hole opens on the surface that mates with the crankcase, and is set so that it becomes a closed seedling after assembly. The reason for this is that this type of aluminum product is easily attacked by seawater, so it is usually treated with marine treatment or painting. This is to prevent corrosion from accelerating in some areas if they enter and remain, and the above surface treatment is assumed to be performed after assembly.

However, since the cylinder block becomes hot after being manufactured, the pressure in the sealed chamber increases, and there is a risk that the gasket in contact with the cylinder block may be damaged. Generally, this solution is solved by providing an air handling hole in this type of cavity, but as mentioned above, this solution cannot be adopted in cases where painting is performed after assembly to prevent residual processing agent. For this reason, parts such as the cylinder block of this type of outboard motor, which are subject to rapid temperature changes, are designed without a sealed chamber, which limits the amount of wall thickness that can be reduced in order to reduce weight. .

On the other hand, it is conceivable to drill the air bleed holes after painting the assembly, but drilling multiple small holes in large parts is not efficient, and at the same time The problem is that it is extremely difficult to drill holes in the surface, so it has not been a solution for commercial products.

(Problems to be Solved by the Invention) As described above, in aluminum die-cast cylinder blocks for outboard motors, the cast holes for thickness reduction are sealed during the painting process, and the corrosion caused by the product is air-filled. There are problems that punch holes are required and that it is difficult to drill holes after painting. This invention solves this problem, and aims to provide a cylinder block for an outboard motor in which an air handling hole can be added very easily after painting to an N handling hole formed in a sealed state. shall be.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above object, in the cylinder block of an outboard motor of the present invention, the fl! In an outboard motor cylinder block that has a cast hole for reducing m, a small diameter cast hole is formed on the outer surface of the cylinder block wall between the cast hole and the outer surface, leaving a thin wall on the deep bottom surface. Take composition.

(Function) With the structure described above, the cast holes made in this cylinder block become a sealed chamber at the beginning of assembly, allowing the painting process to be completed without leaving any obstructions, and the holes added to the outside surface after painting. An air vent hole can be easily formed by inserting a bonder or the like into the cast hole and breaking the thin wall at the bottom.

(Example of actual pus) The following is a detailed explanation of the drawings showing the embodiments of the present invention.

FIG. 1 shows the principle, and an aluminum die-cast cylinder block 1 is joined to a crankcase 2, also made of an aluminum die-cast type, by bolts 4 with a gasket 3 in between. A cast hole 5a is formed in the cylinder block 1 to reduce thickness by 1m due to thinning that opens on the joint surface,
Similarly, $J 1 opens on the joint surface of crankcase 2.
A 1i bored hole 5b is formed. When the cylinder block 1 and the crankcase 2 are joined as described above, the cast holes 5a and 5b are combined to form a sealed cavity.

On the outer surface of the cylinder block wall 7 that separates the cast hole 5a from the cylinder block outer surface 6, a small diameter cast hole 9 is formed which is recessed inward and leaves a thin wall 8 at the deep bottom surface. The existence of the cast hole 9 also allows the cast hole 5a when the cylinder block 1 and the crankcase 2 are joined to each other.
The seal of 5b will not collapse. The assembled form is sent to the painting process or marine treatment process, but the cast hole 5a
.

Degreasing liquid, deoxidizing liquid, or surface treatment liquid does not enter into 5b due to pretreatment. After painting or surface treatment, as shown in FIG. 2, a punch 10 is driven into the cast holes 9 and the thin wall 8 is removed, thereby providing air vent holes in the cast holes 5a and 5b.

As a result, the internal pressure does not change even when the temperature changes, and damage to the gasket 3 can be prevented.

Next, Fig. 3 is a longitudinal side view showing the configuration of a ■-type multi-cylinder engine, Fig. 4 is a rear view of the cylinder block as seen from the arrow B in Fig. 3, and Fig. 5 is a bottom view of the cylinder block as seen from the arrow B. be.

The cylinder block 11 is made of die-cast aluminum and has a bore 12a inserted into the cylinder sleeve.

12b and 12G are installed in parallel. 13a, 13b.

13G is an intake passage, and 14a, 14b, and 14cC are scavenging passages. Adjacent bores 12a and 12b and 12
A cast hole 17 for thickness reduction that opens to the joint surface 16 with the crankcase 15 on the lower surface is formed in the thick wall portion separating the intake passage 13a and the scavenging passage 14b and between the intake passage 13b and the scavenging passage 14C between b and 12c. It is formed. This casting hole 1
7 becomes a sealed chamber when the crankcase 15 is joined.

Next, on the outer surface 19 of the cylinder block wall 18 which separates the cast hole 17 from the outer surface of the cylinder block 11, a small diameter cast hole 21 is formed with a thin wall 20 left on the deep bottom surface.

The above configuration is the same for the rear bank cylinder 11a. When assembled in a V-shape, the front bank and rear bank cylinder blocks 11a and 11b are arranged symmetrically,
Therefore, the cast holes 21 are located facing the opposing surfaces of both. The painting process is carried out in the form of an assembly in which the cast hole 17 is sealed. Thin wall 2 by punch after painting
Punch out 0, v! The handling hole 21 changes into an air bleed hole (shown in the third figure) of the cast hole 17. Casting hole 2 as above
Even if 1 is placed in a narrow space of a V-shaped device, punching with a punch is easy.

〔Effect of the invention〕

As mentioned above, the cylinder block of the outboard motor according to the present invention has a small diameter cast hole with a thin wall remaining from the outer surface surface, compared to the cast hole for thickness reduction, and is used in the painting process etc. A variety of cast holes for thinning the wall are placed in the cylinder blocks of outboard motors, which have complex shapes, to maintain a sealed state and can be easily formed into air bleed holes later. This has the effect of greatly contributing to making the cylinder block of an outboard engine lighter and reducing costs.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the main parts showing the principle of an embodiment of the cylinder block for an outboard motor according to the present invention, FIG. 2 is an enlarged cross-sectional view of the air bleed hole of the cylinder block, and FIG. 4 shows an embodiment of the present invention, and is a longitudinal sectional view showing the main parts of a ■ type multi-cylinder engine of an outboard motor, FIG. 4 is a rear view of the cylinder block as viewed from arrow A in FIG. 3, and FIG. FIG. 3 is a bottom view of the cylinder block as viewed from the arrow in FIG. 1.11... Cylinder block, 2.15... Crank case, 5a, 5b, 17... Cast hole, 8゜2
0... Thin wall, 9.21... Cast hole (for air release), 10... Punch.

Claims (1)

[Claims] In outboard motor cylinder blocks that have a cast hole for weight reduction that is sealed by joining with the crankcase, etc., a thin wall is added to the outer surface of the cylinder block wall between the cast hole and the outer surface. An outboard motor cylinder block characterized by forming a small diameter cast hole.