JPH0253623B2 - - 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, in the case of engine blocks, it has been common to form a water jacket c for cylinder cooling between the cylinder head mounting frame a and the cylinder b, as shown in Figs. 6 and 7. In the die-cast engine block, the water jacket c is formed by forming the inner wall d of the cylinder head mounting frame a and the outer wall e of the cylinder b into concentric circles with different diameters, and after die-casting, a core (not shown) is formed as shown in FIG. It is formed by being extracted in the direction of arrow f.

However, although the cylinder head mounting frame a and cylinder b are connected at the inner end g, they are not connected at the outer end h, so when the cylinder is in use, that is, during piston operation, the cylinder b The problem was that the outer end vibrated. Especially when it comes to large engine blocks with a displacement of 1500 c.c. or more,
This tendency is noticeable.

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

[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, the water jacket part c
The bridge part is formed by die casting using a collapsible core or shell core, but this requires complicated work to remove the core sand after casting, resulting in low productivity. There are problems such as high cost.

The present invention is an attempt to solve the above-mentioned conventional problems, and aims to provide a die-cast engine block that can be cast with high productivity and at low cost by being configured so that a waste core can be used. is its purpose.

[Means for solving problems]

That is, the present invention provides a die-cast engine block in which the inner wall of a cylinder head mounting frame and the outer end of the outer wall of the cylinder are connected by a bridge portion, in which the inner wall and outer wall of at least one side of each bridge portion are connected to each other. One or both of the opposing surfaces are formed into inclined planes that are inclined at a desired angle from the bridge portion side to the other side to form a water jacket portion whose width is narrow on the bridge portion side and gradually widens from there to the other side. and an inner end surface of the bridge portion is provided as an inclined surface that slopes upward from one end in a direction in which the width of the water jacket portion is widened;
This solved the problems mentioned above.

〔Example〕

Embodiments of the present invention will be described below in detail based on the drawings. As shown in FIGS. 1 to 3, a cylinder head mounting frame 1, a cylinder 2 with a cast iron runner 3 inserted into the inner circumference, etc. an inner wall 1a of the cylinder head mounting frame 1;
A water jacket portion 4 for cooling the cylinder 2 is formed between the cylinder 2 and the outer wall 2a of the cylinder 2.

The outer wall 2a of the cylinder 2 at a substantially intermediate portion in the length direction is connected to the inner wall 1a of the cylinder head mounting frame 1 and the bottom wall 4 of the water jacket 4.
a, and the outer end of the outer wall 2a of the cylinder 2 and the cylinder head mounting frame 1
The outer ends of the inner walls 1a are connected by a plurality of bridge parts 5, whereby the cylinder head mounting frame 1 and the cylinder 2 are integrally connected.

Further, in the present invention, each bridge portion 5 is formed as follows so that it can be die-cast using a waste core.

That is, one or both of the facing surfaces of the inner wall 1a of the cylinder head mounting frame 1 and the outer wall 2a of the cylinder 2 at one side portion of each bridge portion 5 are symmetrically inclined outward by predetermined angles α and β. so that the inclined planes 1b and 2b are formed, and the distance l between the inner wall 1a and the outer wall 2a is the narrowest on the bridge portion 5 side,
It is provided so that it gradually expands from this to the other side (to the left in FIG. 1), thereby making the water jacket portion 4 narrower on the bridge portion 5 side at one side portion of the bridge portion 5. It is formed so that it gradually expands in the left direction.

Also, the length m from the left end of the bridge portion 5 in FIGS. 1 and 2 to the end of the inclined plane 1b of the inner wall 1a of the cylinder head mounting frame 1.
is formed to be longer than the horizontal width n of the sacrificial core 6 by an appropriate dimension, thereby allowing the sacrificial core 6 to be moved along the water jacket portion 4 in the direction of arrow A in FIGS. 1 and 2. After sliding, it can be pulled out in the direction of arrow B in FIG.

Next, an example of die casting of the above-mentioned engine block of the present invention will be explained.

FIG. 4 shows a cross-sectional view of a mold for casting the engine block of the present invention, and FIG. 5 shows a -
A sectional view taken along the line is shown.

In the above figure, 3 is a cast iron liner, 6 is a waste core, 7 is a cavity of the bridge part 5, 8 is a movable die, 9 is a core die, 10 is a fixed die, 1
1 is a product cavity, 12 is a waste core for a water jacket, and 13 is a cylinder head mounting frame cavity.

When the mold is opened, the movable die 8 slides in the direction of arrow C shown, and the core die 9 slides in the direction of arrow D.

In FIG. 5, when the core die 9 has not slid to the illustrated position, insert the discarded core 6 for forming the bridge part 5 into the movable die 8 from the direction of arrow E,
The tip 6a of the discarded core 6 is inserted into the recess 8 of the movable die 8.
A is fitted and held.

The abandoned 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. and a part of the sacrificial core 6.

When die casting is performed using the illustrated mold configuration, each cavity 7, 11, 13 is filled with molten metal, and the product (engine 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 extracted from the product.

The procedure for removing the sacrificial core 6 is as shown in Figure 2. First, slide the sacrificial core 6 in the direction of arrow A to the position indicated by the two-dot broken line in the figure, then slide it in the direction of arrow B and remove it. .

The above-mentioned discarded core 6 may be removed manually or by using appropriate tools and machines.

〔Effect of the invention〕

Since the die-cast engine block according to the present invention is configured as explained above, the outer end of the inner wall 1a of the cylinder head mounting frame 1 and the outer end of the inner wall 1a of the cylinder head mounting frame 1,
in which the outer ends of the outer wall 2a of the cylinder head are connected by a plurality of bridge parts 5..., one or both of the facing surfaces of the inner wall 1a of the cylinder head mounting frame 1 and the outer wall 2a of the cylinder 2 are formed into an inclined plane 1b. , 2b, and the inner end surface of the bridge portion 5 is formed into an inclined surface 5.
Since it is formed in the shape of a shape and installed at the draft angle, it can be die-cast using the disposable core 6 which can be used repeatedly, so there is no need to manufacture a collapsible core or a shell core, and it is possible to use these. This eliminates the need for the complicated removal work of the core sand that is generated during the process, and has the advantage that an engine block that can prevent the vibration of the cylinder 2 can be cast with high productivity by the die-casting method and can be provided at a low cost.

[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. A vertical cross-sectional view showing a mold for die-casting.
6 is a plan view showing a conventional die-cast engine block, and FIG. 7 is a sectional view taken along the - line in FIG. 6. DESCRIPTION OF SYMBOLS 1... Cylinder head mounting frame, 1a... Inner wall, 1b, 2b... Inclined plane, 2... Cylinder, 2a... Outer wall, 4... Water jacket part, 5... Bridge part, 5a... Inclined surface. .

Claims (1)

[Claims] 1. In a die-cast engine block in which the inner wall of the cylinder head mounting frame and the outer end of the outer wall of the cylinder are connected by a plurality of bridge parts, the facing surface between the inner wall and the outer wall of at least one side part of each bridge part. forming one or both of them into an inclined plane that slopes at a desired angle from the bridge portion side to the other side to form a water jacket portion whose width is narrow on the bridge portion side and gradually widens from there to the other side; The inner end surface of the bridge part,
A die-cast engine block characterized in that it is formed with an inclined surface that slopes upward from one end in a direction in which the width of the water jacket portion increases.