JP3488788B2 - Shell type for forming cylinder sleeve assembly - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder sleeve aggregate forming shell die for forming a so-called Siamese type cylinder sleeve aggregate.

[0002]

2. Description of the Related Art A shell mold for molding such a cylinder sleeve assembly has already been proposed by the present applicant in Japanese Patent Application No. 7-179890.

In the above conventional shell mold, an upper mold and a lower mold are bonded with a bore core sandwiched therebetween to define a sleeve molding cavity, and a molten metal is supplied to the sleeve molding cavity to form a cylinder sleeve assembly. It is designed to be molded.

[0004]

FIG. 7 shows a state in which the shell mold D is assembled. The four mold cores 3 ₁ are placed on the lower mold 2 which is placed horizontally on the table with the split surface 2 ₁ facing upward. to 3 ₄
Was placed, so as to bond was what parting plane 1 _1, 2 ₁ covered with a upper mold 1 was down the split surfaces 1 ₁ thereon. At this time, since pressure is applied to the upper mold 1 in the direction of the arrow in order to ensure the adhesion, the longitudinal surfaces of the split surfaces 1 ₁ , 2 ₁ after the adhesion are curved downward. Therefore, as shown in FIG. 8, in the cylinder sleeve assembly S formed by the curved shell mold D as well, the centers O ₁ ′ to O ₄ ′ of the cylinder bores are curved with respect to the original centers O _{1 to} O ₄ . It is displaced to the outside, and in particular, the amounts of displacement of the centers O ₂ ′ and O ₃ ′ of the two inner cylinder bores are large.

When the cylinder bore of the formed cylinder sleeve assembly S is ground as shown by the chain line to remove the black skin, the center of the grinding tool is displaced from the center O ₁ ′ to O ₄ ′ of the cylinder bore. Original center O ₁ different from
Positioned at O ₄ . Therefore, especially in the two inner cylinder bores, the inner wall surface of the cylinder bore located on the outer side in the curving direction has no cutting allowance, and the black skin which is the background of molding may remain in that portion (Fig. (See Part A of 8).

The present invention has been made in view of the above circumstances, and an object of the present invention is to reliably prevent the black skin of the cylinder bore from remaining due to the bending of the cylinder sleeve assembly.

[0007]

According to a first aspect of the present invention, the bore core disposed inside the upper die and the lower die has an elliptical cross section, and its major axis has an upper diameter and a lower diameter. Since it is arranged in the direction along the split surface of the mold, the wall thickness of the molded cylinder sleeve increases at the portion corresponding to the minor diameter of the bore core. When the center of each cylinder bore of the cylinder sleeve deviates to the outside in the bending direction from the original center due to the shell-shaped curve, even if the cutting tool for grinding the cylinder bore is positioned at the original center, the thickness of the cylinder sleeve described above As a result, a sufficient cutting allowance can be secured on the inner wall surface of the cylinder bore located on the outer side in the bending direction, and the black scale can be prevented from remaining.

According to the second aspect of the present invention, the positioning means provided between the upper die and the lower die and the bore core makes it possible to divide the major axis of the bore core having an elliptical cross section into the upper die and the lower die. Positioning can be reliably performed in the direction along the surface.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on the embodiments of the present invention shown in the accompanying drawings.

1 to 6 show an embodiment of the present invention. FIG. 1 is a cross-sectional view of a shell type (cross-sectional view taken along line 1-1 in FIG. 2), and FIG. 2 is 2-2 in FIG. 2 is a sectional view taken along line 3-3 of FIG. 2, and FIG. 4 is 4 of FIG.
-4 line expanded sectional view, FIG. 5 is a perspective view of the cylinder sleeve assembly, and FIG. 6 is an operation explanatory view.

FIG. 5 shows a cylinder sleeve assembly S formed by the shell mold of this embodiment. The cylinder sleeve assembly S is for an in-line 4-cylinder internal combustion engine,
Formed by bonding together the four Aitonaru peripheral wall of the cylinder sleeve S ₁ to S _4.

As shown in FIGS. 1 to 4, the shell mold D is composed of an upper mold 1, a lower mold 2, and four bore cores 3 _{1 to} 3 ₄ formed of resin sand, and two shell molds D The cylinder sleeve assemblies S, S can be simultaneously molded. The upper mold 1 and the lower mold 2 are formed in plane symmetry with respect to the split surfaces 1 ₁ and 2 ₁ to which they are joined by adhesion,
On the split surfaces 1 ₁ and 2 ₁ , a sprue 4 extending in the vertical direction,
A pair of upper and lower runners 5 and 5 extending in the horizontal direction are formed from the middle portion and the lower portion of the sprue 4.

4 pieces so as to be sandwiched between the upper die 1 and the lower die 2
Boa core 3₁~ 3_FourAre placed, and these four
Boa core 3₁~ 3_FourBetween the upper mold 1 and the lower mold 2
Sleeve molding cavity 6₁~ 6_FourIs formed. 4 pieces
Sleeve molding cavity 6 ₁~ 6_FourIs 3 communicating parts
7₁~ 7₃Communicate with each other via the
4 weirs 8 formed in a ring shape₁~ 8_FourThrough
Connect to the runway 5.

Boa core 3₁~ 3_FourCross section is oval
And its major axis d₁Is split surface 1₁, 2 ₁Place in the direction along
And its minor axis d₂Is split surface 1₁, 2₁Direction orthogonal to
Is located in. 4 series of cylinder sleeve assembly S
The dobo bore is cut with a cutting tool to remove the black skin.
However, the major axis d of the ellipse with respect to the diameter of this cutting tool₁Is very small
It is set to a small size.

A positioning portion 9 having a diameter smaller than that of the cylinder bore is provided at an intermediate portion of each of the bore cores 3 _{1 to} 3 ₄ .
A pair of first positioning surfaces 9 ₁ , 9 ₁ is formed in each positioning portion 9 by cutting out both ends in the diameter direction in parallel. On the other hand, the upper mold 1 and the lower mold 2 have four positioning parts 1 between the upper and lower sleeve molding cavities 6 _{1 to} 6 _4.
0, and a pair of second positioning surfaces 1 with which the first positioning surfaces 9 ₁ , 9 ₁ engage with each positioning portion 10
0 ₁ and 10 ₁ are formed.

When the bore cores 3 _{1 to} 3 ₄ are clamped between the upper mold 1 and the lower mold 2, the pair of first positioning surfaces 9 ₁ and 9 ₁ of each of the bore cores 3 _{1 to} 3 ₄ is attached to the upper mold 1. And by engaging the second positioning surfaces 10 ₁ and 10 ₁ of the lower die 2 with the major axis d ₁ of the bore cores 3 _{1 to} 3 _{4 having} an elliptical cross section, the split surfaces of the upper die 1 and the lower die 2 The direction of 1 ₁ and 2 ₁ can be surely matched.

Then, the upper die 1 and the lower die 2 having the _four bore cores 3 _{1 to} 3 ₄ incorporated therein are joined by adhesion so that the spout 4 is vertical and the runners 5 and 5 are horizontal. The molten metal is injected from the sprue 4 by gravity while being set so that The poured molten metal is supplied from the sprue 4 to each runner 5 and the weirs 8 ₁ to 8 ₄
Flows into the sleeve mold cavity ₆₁ through ₄ via, 4
A cylinder sleeve assembly S in which the individual cylinder sleeves S _{1 to} S ₄ are integrally connected is molded.

It is added when the upper mold 1 and the lower mold 2 are bonded.
Split surface 1 of upper mold 1 and lower mold 2 due to pressure₁, 2₁Is an arc
Cylinder shaped as shown in FIG.
Center O of each cylinder bore of the sleeve assembly S₁′ 〜
O_Four′ Is the original center O₁~ O_FourTo the outside in the bending direction
It is displaced, especially the center of the two inner cylinder bores
O ₂′, O₃The shift amount of ′ becomes large. However,
Bore core 3 with an oval cross section ₁~ 3_FourBy cylinder
The shape of a becomes elliptical, and its minor axis d₂Direction is front
Match the curved direction. Therefore, the original of the cylinder bore
Center O₁~ O_FourPosition the grinding tool on the cylinder bore
When performing grinding, the center O of the actual cylinder bore₁′ 〜
O_Four′ Is the original center O₁~ O_FourEccentric to
However, the inner wall on the outer side of the cylinder bore in the bending direction (the portion A in FIG. 6)
(See also) to ensure sufficient cutting allowance and ensure that black skin remains
Can be prevented.

In the cylinder sleeve assembly S after the grinding of the cylinder bores, there is a difference in wall thickness between the outer wall portion in the bending direction and the inner wall portion in the bending direction, but the difference is slight, and the cylinder sleeve assembly is small. Since the body S itself is cast in a cylinder block made of aluminum, there is no particular problem.

The embodiments of the present invention have been described in detail above, but the present invention can be modified in various ways without departing from the scope of the invention.

For example, although four cylinder sleeve assemblies S are illustrated in the embodiment, the present invention can be applied to a shell type of multiple cylinder sleeve assemblies S other than four. Further, the numbers and shapes of the first positioning surfaces 9 ₁ and 9 ₁ and the second positioning surfaces 10 ₁ and 10 ₁ are not limited to those in the embodiment and can be set arbitrarily.

[0022]

As described above, according to the invention as set forth in claim 1, a plurality of bore cores arranged inside the upper die and the lower die to be joined at the split surface to form the inner wall of the cylinder bore. Since the cross section of was formed into an elliptical shape and its major axis was arranged in the direction along the split surface, the upper mold and the lower mold were curved during joining, and the axis of each cylinder sleeve after molding was not in the same plane. Also, when cutting the cylinder bore, it is possible to sufficiently secure the cutting allowance of the inner portion of the cylinder bore in the bending direction, and to reliably prevent the black skin from remaining.

According to the invention described in claim 2,
In order to arrange the major axis of the bore core having an elliptical cross section in the direction along the split surface, the positioning means is provided between the upper mold and the lower mold and the bore core. When set in between, the direction of the major axis can be surely matched with the direction along the split surface.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a shell type (cross-sectional view taken along line 1-1 of FIG. 2).

FIG. 2 is a view taken along the line 2-2 of FIG. 1 (a diagram showing a split surface of the upper mold).

3 is a sectional view taken along line 3-3 of FIG.

4 is an enlarged sectional view taken along line 4-4 of FIG.

FIG. 5 is a perspective view of a cylinder sleeve assembly.

FIG. 6 is an operation explanatory diagram

FIG. 7 is an explanatory view of a process of bonding the upper mold and the lower mold.

FIG. 8 is an operation explanatory view of a conventional example.

[Explanation of symbols]

1 Upper mold 1 ₁ Split surface 2 Lower mold 2 ₁ Split surface 3 _{1 to} 3 ₄ Bore core 9 ₁ 1st positioning surface (positioning means) 10 ₁ 2nd positioning surface (positioning means) S Cylinder sleeve assembly S ₁ ~ S ₄ cylinder sleeve

Front page continued (72) Inventor Taichi Yoshikawa 1907 Hirata-cho, Suzuka-shi, Mie Honda Motor Co., Ltd. Suzuka Factory (72) Inventor Kiyoyoshi Matsumoto 1907 Hirata-cho, Suzuka-shi, Mie Honda Suzuka Co., Ltd. (56) References JP-A-6-190504 (JP, A) JP-A-9-29386 (JP, A) JP-A-8-52531 (JP, A) JP-A-7-243509 (JP, A) JP-A-52-73212 (JP, A) JP-A-50-73016 (JP, A) Fukukaihei 5-65448 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B22C 9/02 B22C 9/24

Claims (2)

(57) [Claims] 1. A cylinder sleeve assembly for forming a cylinder sleeve assembly (S), which comprises integrally connecting a plurality of cylinder sleeves (S _{1 to} S ₄ ) of a multi-cylinder internal combustion engine at adjacent peripheral wall portions. In the shell mold, a plurality of bore cores (3 _{1 to} 3) arranged inside the upper mold (1) and the lower mold (2) to be joined at the split surfaces (1 ₁ , 2 ₁ ) to mold the inner wall of the cylinder bore. _A shell mold for forming a cylinder sleeve assembly, characterized in that the cross section of ₄ ) is formed into an elliptical shape, and the major axis thereof is arranged in the direction along the split surface (1 ₁ , 2 ₁ ). 2. A bore core (3 _{1 to} 3 ₄ ) having an elliptical cross section.
Of the upper mold (1) and the lower mold (2) and the bore cores (3 ₁ to 3) in order to arrange the major axis of the mold in the direction along the split surface (1 ₁ , 2 ₁ ).
_The shell mold for molding a cylinder sleeve assembly according to claim 1, characterized in that a positioning means (9 ₁ , 10 ₁ ) is provided between the mold and the cylinder.