JP3003464B2 - Cylinder block casting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for casting a cylinder block of an internal combustion engine.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 1-150429 discloses that a cylinder liner is press-fitted into a liner holder provided on one of a pair of dies and temporarily fixed. A method of casting a cylinder block in which a mold is opened and a cylinder block having an integral cylinder liner is taken out by an extrusion pin is disclosed.

[0003]

However, since the cylinder liner to be cast is press-fitted into the liner holder and fixed to the upper die, the product is not released smoothly when the product is extruded and released from the die after casting. There is a problem in that a strong extrusion force is applied, and the product is cracked or distorted.
SUMMARY OF THE INVENTION An object of the present invention is to provide a cylinder block casting method that requires a small pushing force of a product after casting from a mold.

[0004]

Means for Solving the Problems] Cylinder block casting method of the present invention for achieving the above object consists of the following ways. On the outer periphery of the liner holder provided on one of the pair of molds
Holds a cylindrical cylinder liner longer than the liner holder
Then , the cylinder liner is clamped by the pair of molds.
In the axial direction to apply the expanding force to the cylinder liner.
The cylinder liner is deformed into a barrel shape to
Form a gap between the inner holder and the cylinder liner
And, gap between the cylinder liner and the Rainahoruda
In a state where there is a gap, a molten metal is poured around the outer periphery of the cylinder liner and solidified to cast a cylinder block having an integral cylinder liner, and the mold is opened to form a cylinder block having an integral cylinder liner from the one-liner holder. take out of you, shea cylinder block casting process.

[0005]

According to the cylinder block casting method of the present invention , the molten metal is cast and solidified in a state where there is a gap between the liner holder and the cylinder liner. Therefore, the engaging force between the liner holder and the cylinder liner is weakened, and the mold is opened. The product removal force when the product is extruded from the mold is reduced, and the product is prevented from being cracked or distorted.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described with reference to the drawings. 1, FIG. 2 shows an embodiment of the present invention. The configuration and operation of the embodiment of the present invention will be described with reference to FIGS. In one of the pair of dies 1 and 2, for example, of the pair of dies including the upper die 1 and the lower die 2, the upper die 1 is provided with a liner holder 3 integrally with or separate from one of the dies. Then, a cylindrical cylinder liner 4 is press-fitted and held in the liner holder 3. This press-fitting is for temporarily fixing the cylinder liner 4 to one mold, and the cylinder liner 4 is removed from the liner holder 3 after casting.

Next, a pair of dies 1, 2 and a slide core 6 are provided.
, The molten metal, for example, molten aluminum is poured into the cavity on the outer peripheral side of the cylinder liner 4 and solidified to cast a cylinder block having the cylinder liner 4 integrally. In this case, when the mold is clamped, the cylinder liner 4 is placed in a state having a radial gap 5 between the cylinder liner 4 and the liner holder 3,
The pouring is performed in that state. The method of forming the radial gap will be described later .

Next, the mold is opened, and the cylinder block integrally having the cylinder liner 4 is pushed out with an extrusion pin and removed from one mold, for example, the upper mold 1. At this time, the cylinder liner 4 comes off the liner holder 3. Thereafter, the surfaces to be machined, such as the upper surface of the cylinder block and the inner surface of the cylinder liner, are machined to finish.

The above method has the following effects. That is, the molten metal is cast into the cylinder liner outer peripheral cavity in a state where the gap 5 is formed between the cylinder liner 4 and the liner holder 3, so that the gap 5 is retained when the molten metal solidifies, and the solidified cylinder liner 4 And liner holder 3
Is weaker than when there is no gap 5. Therefore, when the cylinder block is pushed out of the mold when the mold is opened, it can be easily and smoothly pushed out. for that reason,
Damage or distortion of the cylinder block due to excessive pushing force is prevented.

As shown in FIG. 1, when forming the radial gap 5 , the cylinder liner 4 is made longer than the liner holder 3, and when the cylinder liner 4 is pressed into the liner holder 3, the lower end of the cylinder liner 4 is closed. It protrudes downward from the lower end of the liner holder 3 by 0.1 to 1.5 mm. Then, when the molds are clamped, as shown in FIG. 2, the cylinder liner 4 is compressed in the axial direction by the pair of molds 1 and 2, and is reduced by the above-described protrusion amount of 0.1 to 1.5 mm, At the same time, the cylinder liner 4 is expanded.
And almost deformed into a barrel shape. As a result, a radial gap 5 is formed between the cylinder liner 4 and the liner holder 3.
In this state, the molten metal is cast into the outer peripheral cavity of the cylinder liner 4 and solidified. Even when the mold is opened due to solidification of the molten metal, a gap 5 exists between the cylinder liner 4 and the liner holder 3. Therefore, the cylinder liner 4
The engagement force between the cylinder block and the liner holder 3 is weakened, and the cylinder block can be easily removed from the upper mold 1 with a relatively small pushing force after the mold is opened.

In the above, the protrusion amount is 0.1 to 1.5 m
The reason for setting m is as follows. When the diameter is smaller than 0.1 mm, the cylinder liner 4 has a small barrel-shaped deformation amount and the gap 5 is small, so that the cylinder liner 4 and the liner holder 3
Is not weakened sufficiently. On the other hand, if the diameter is larger than 1.5 mm, the barrel deformation generated in the cylinder liner 4 becomes too large, and the cylinder liner 4 is damaged by excavation or the distortion becomes too large to exceed the machining allowance. Is caused.

Next, a test was conducted to determine a decrease in liner pulling force according to each embodiment, and the results are shown. In the test, the length of the liner holder was 143.8 mm. The test was conducted by changing the conditions of the cylinder liner to various types. The relationship between the conditions of the cylinder liner and the pulling force was as follows. Shape Straight Barrel Length (mm) 143.8 143.9 Surface Roughness 25Rz 25Rz 42.5 29.5 44.5 24.8 Removal Force 51.9 (tons) 53.8 43.8 38.5 Average 45 8.8 38.5 27.2 Ratio (%) 100 84.0 59.2 Effect (%) 16 40.8 FIG. 3 shows the result of the above-described pulling force, and FIG. As shown in FIG. From these tests, it was found that approximately 40 %
It was found that there was a decrease in the pulling force.

[0013]

According to the cylinder block casting method of the present invention,
For example, on the outer circumference of the liner holder
Holds a cylindrical cylinder liner longer than the liner holder
Then , the cylinder liner is clamped by the pair of molds.
In the axial direction to apply the expanding force to the cylinder liner.
The cylinder liner is deformed into a barrel shape to
Form a gap between the inner holder and the cylinder liner
And, gap between the cylinder liner and the Rainahoruda
Pour molten metal around the cylinder liner
Cylinder block with solidified cylinder liner
Cast the mold, open the mold and have the cylinder liner integrated
Remove the cylinder block from the one type of liner holder
Rihazusu, since the the above, it is possible to smoothly take out a small pushing force when unmolding from mold opening to cast cylinder block. In addition, the diameter is expanded to the cylinder liner when closing the mold.
Applying force offsets liner deformation against casting pressure
In this case, cracking and distortion of the product can be eliminated, product yield can be improved, and product cost can be reduced. In addition, the interruption of the casting cycle due to defective release of the product from the mold is reduced, and the productivity can be improved. Further, since the pushing force required for the release is small, the pushing mechanism provided in the mold and the casting facility can be simplified, and the mold and the casting facility can be downsized.

[Brief description of the drawings]

[1] of the cylinder block casting according to Kazumi施例of the present invention, is a cross-sectional view of a state where press-fitting the cylinder liner to Rainahoruda.

[2] the method of the present onset AkiraMinoru施例is a cross-sectional view of a state that made the gap between the cylinder liner and Rainahoruda by clamping.

FIG. 3 is a relationship diagram between a pulling force (ton) and a cylinder liner condition.

FIG. 4 is a relationship diagram between a pulling force (%) and a cylinder liner condition.

[Explanation of symbols]

 1 upper mold 2 lower mold 3 liner holder 4 cylinder liner 5 gap

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-61-219458 (JP, A) JP-A-6-126428 (JP, A) JP-A-3-155448 (JP, A) 66130 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B22D 19/08 B22D 17/00 B22D 17/24 F02F 1/00

Claims (1)

(57) [Claims] 1. A cylinder liner having a cylindrical shape longer than the liner holder is held on the outer periphery of a liner holder provided on one of a pair of dies , and the cylinder liner is axially moved by the pair of dies.
Direction to expand the cylinder liner.
The cylinder liner is deformed into a barrel shape to
A gap is formed between the cylinder liner and the cylinder liner, and a gap is formed between the liner holder and the cylinder liner.
In a certain state, the molten metal is poured around the cylinder liner and solidified to cast a cylinder block integrally having the cylinder liner . The mold is opened and the cylinder block integrally including the cylinder liner is removed from the one-type liner holder. be, shea cylinder block casting process.