JPH0253624B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a die-cast engine block made of, for example, an aluminum alloy.

[Conventional technology]

Conventionally, for engine blocks, Fig. 6,
As shown in Figure 7, the cylinder head mounting frame a
Generally, a water jacket c for cooling the cylinder is formed between the cylinder head mounting frame a and the cylinder b, but in a die-cast engine block, the water jacket c is formed between the inner wall d of the cylinder head mounting frame a and the cylinder The outer wall e of b is formed into concentric circles of different diameters, and after die casting, a core (not shown) is extracted in the direction of arrow f in FIG. 7 to form the outer wall e.

However, although the cylinder head mounting frame a and the cylinder b are connected at the inner end g (bottom wall of the water jacket c), they are not connected at the outer end h, so when the cylinder is used ,
In other words, there was a drawback that the outer end of cylinder b vibrated during piston operation. This tendency is especially noticeable when it comes to large engine blocks with a displacement of 1500 c.c. or more.

Therefore, in order to prevent the above-mentioned vibration, an engine block is currently known in which a cylinder head mounting frame a and an outer end of a cylinder b are connected to each other by a plurality of bridge portions.

[Problem that the invention seeks to solve]

However, when the bridge portion is provided, the core cannot be removed in the die-casting method.

For this reason, conventionally, water jackets have been die-cast using a collapsible core or a shell core to form the bridge part, but this requires complicated work to remove the core sand after casting. However, there are problems such as low productivity and high cost.

The present invention is an attempt to solve the above-mentioned conventional problems, and uses a waste core that can be used repeatedly by only slightly modifying a part of the conventional mold in a die-cast engine block equipped with a bridge part. The object of the present invention is to provide a die-cast engine block that can be cast at a low cost and improves productivity by being constructed so that it can be die-cast.

[Means for solving problems]

That is, the present invention provides a die-cast engine block in which the inner wall of the cylinder head mounting frame and the outer end of the cylinder are connected by a plurality of bridge parts. A water jacket is provided by forming an arcuate space between the bridge part and the water jacket, which is narrow on the bridge part side and gradually widens from there to the other side, and the inner end surface of the bridge part and the water jacket opposite thereto. The inner end surfaces of the inner end surfaces are formed into symmetrical inclined surfaces such that the distance between the two inner end surfaces is larger at one end and smaller at the other end on the side where the distance between the inner and outer walls is enlarged. This solved the above-mentioned problems.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.As shown in FIGS. 1 to 3, the engine block A includes a cylinder head mounting frame 1, a cylinder 2 into which a cast iron liner 3 is inserted...
and the above-mentioned cylinder head mounting frame 1.
A water jacket 4 for cooling the cylinder is formed between the inner wall 1a of the cylinder 2 and the outer wall 2a of the cylinder 2.

Approximately the middle part of the outer wall 2a in the length direction of the cylinder 2 is located at the inner wall 1 of the cylinder head mounting frame 1.
a and the bottom wall 4a of the water jacket 4, and the outer wall 2a of the cylinder 2.
and the inner wall 1a of the cylinder head mounting frame 1.
The outer ends of the cylinder head mounting frame 1 and the cylinder 2 are connected to each other by a plurality of bridge parts 5, so that the cylinder head mounting frame 1 and the cylinder 2 are integrally connected.

Further, the present invention is configured as follows so that die casting can be performed using a discarded core 6 as shown in FIG.

That is, the inner wall 1 of the cylinder head mounting frame 1
a and the facing surface 1b of the outer wall 2a of the cylinder 2,
2b, a narrow gap part l' formed in a tapered shape that narrows and widens in the direction of arrow B at one end of the cylinder 2 on the bridge part 5 side in the circumferential direction, and an enlarged gap continuing from the narrow gap part l'. The narrow gap l' is formed in an arc shape so as to gradually widen from one end to the other, and the gap l' is formed in a draft direction.

In addition, step portions 1' and 2' are provided at the interface between the narrow space part l' and the wide space part l'', as shown in FIG. 6 is in contact with the opposing surfaces 1b and 2b, so that it does not become difficult to remove.

Further, the inner end surface of the bridge portion 5 and the inner end surface (inner surface of the bottom wall) of the water jacket 4 opposing the inner end surface are arranged so that the discarded core 6 is directed in the direction of arrow B shown in FIGS. 1 and 2. They are formed into symmetrical inclined surfaces 5a and 1c so that they can be pulled out.

Incidentally, the inclination angles of the above-mentioned both inner end surfaces may be different,
Alternatively, a configuration may be adopted in which only one of the two end surfaces is provided with an inclined surface.

Next, a casting example of the engine block A of the present invention will be explained based on FIGS. 4 and 5.

Figures 4 and 5 show cross-sectional views of the mold. In the figures, 3 is a cast iron liner, 6 is a waste core, 7 is a bridge cavity, 8 is a movable die, and 9 is a core die. , 10 indicates a fixed die, and 11 indicates a cavity of the product (cylinder block).

When the mold is opened, the movable die 8 slides in the direction of arrow E, and the core die 9 slides in the direction of arrow F.

When the core die 9 is not slid to the position shown in FIG. is fitted into and held in the recess 13 of the movable die 8.

The sacrificial core 6 consists of a tip 6a, an intermediate portion 6b narrower than the tip 6a, and a rear end 6c wider than the tip 6a.

The bridge cavity 7 has a movable die 8
and a part of the sacrificial core 6.

When die-casting is performed using a mold having the structure shown, each cavity 7, 11 is filled with molten metal, and the product (cylinder block) shown in FIG. 1 is cast.

After opening the mold, the product is taken out with the waste core 6 still attached to the bridge part 5, and the waste core 6 is removed from the product.

The means for removing the sacrificial core 6 is to first slide the sacrificial core 6 in the direction of arrow B in FIG. 2 (in the direction of arrow B in FIG.
Slide it in the direction and remove it.

The discarded core 6 may be removed manually or by using a suitable tool or machine.

〔Effect of the invention〕

Since the die-cast engine block according to the present invention is configured as explained above, the bridge portion 5
In addition to preventing vibrations and reinforcing the cylinder 2, the bridge part 5 can be formed by simply modifying a part of the conventional mold, and die casting can be performed using a reusable waste core 6. This eliminates the need to manufacture conventional collapsible cores and shell cores, and also eliminates the complicated work of removing core sand that occurs when these are used, improving productivity and making it possible to manufacture at low cost. There are advantages.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an embodiment of a die-cast engine block according to the present invention, Figs. 2 and 3 are sectional views taken along the - line and - line in Fig. 1, and Fig. 4 is a plan view of the same engine block. FIG. 5 is a cross-sectional view taken along the - line in FIG. 4, FIG. 6 is a plan view showing a conventional die-cast engine block, and FIG. It is a sectional view taken along the - line in FIG. 1... Cylinder head mounting frame, 1a... Inner wall, 2... Cylinder, 2a... Outer wall, 4... Water jacket, 5... Bridge portion, 1c,
5a... Inclined surface, l... Interval.

Claims (1)

[Claims] 1. In a die-cast engine block formed by connecting the outer ends of the inner wall of the cylinder head mounting frame and the outer wall of the cylinder with a plurality of bridge parts, there is a gap between the inner wall of the cylinder head mounting frame and the outer wall of the cylinder. A water jacket is provided by forming an arcuate interval that is narrow on one side of the bridge section in the circumferential direction of the cylinder and gradually widens from there to the other side, and between the inner end surface of the bridge section and the opposite end of the bridge section. A die-cast engine block characterized in that at least one of the inner end surfaces of the water jacket is formed as an inclined surface so that the distance between the two inner end surfaces increases in the direction of increasing the distance between the inner and outer walls. .