JPH06190504A - Method and device for manufacturing sand mold for forming cylinder sleeve assembly - Google Patents

Abstract

PURPOSE:To provide a method and a device for manufacturing a sand mold for casting with high precision a cylinder sleeve assembly which is cast in a cylinder block for a multicylinder internal combustion engine. CONSTITUTION:As a sand mold manufacturing device 10 for forming a cylinder sleeve assembly 1 to which plural sleeves 2 are connected, a product nest 13 of the same shape as an external shape of the cylinder sleeve assembly 1 is provided, a projecting sand mold 6 of the same shape as a recessed part of this product nest 13 is set to each recessed part, and this projecting sand mold 6 is pressed and positioned by a pressing/positioning mechanism 15 of the upper mold hot plate 14. Subsequently, shell sand is poured from a sand pouring port 26 and the inside of a space part S is filled therewith, and by heating and hardening it, a main mold is formed, and in this case, the projecting sand mold 6 is formed integrally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a sand mold manufacturing method and apparatus for casting a cylinder sleeve assembly cast in a cylinder block for a multi-cylinder internal combustion engine.

[0002]

2. Description of the Related Art For example, a cylinder sleeve assembly 1 cast in a cylinder block of a multi-cylinder engine for an automobile.
As shown in FIG. 4, a plurality of sleeves 2, ... And a connecting portion 3 where adjacent sleeves 2 and 2 are connected are integrally cast as a whole. When attempting to cast the cylinder sleeve assembly 1 having such a configuration, shrinkage or the like is likely to occur in the vicinity of the connecting portion 3, so that shrinkage-preventing unevenness is formed on the outer surface of the portion where the sleeves 2 and 2 are joined. It is common to form part 4. Therefore, conventionally, the connecting portion 3 is used as a sand mold for molding the outer peripheral portion of the cylinder sleeve assembly 1.
In order to form a complicated outer surface shape of the valley-shaped recess 5 formed in the periphery, a protruding sand mold 6 as shown in FIG. At the same time, a main mold for molding the other outer peripheral portion is separately formed, and the protruding sand mold 6 is fixed to the main mold with an adhesive. That is, as shown in FIG.
Is a product insert 53 that is attached to the lower plate 51 with bolts 52.
And the core insert 55 which is attached to the product insert 53 with the bolt 54, and the key member 5 which is attached to the lower plate 51.
6 and an upper mold hot plate 57 that can move up and down, and the sand mold molding machine 50 is used to manufacture a half-divided body of the cylinder sleeve assembly 1. That is, shell sand is poured from a plurality of sand pouring ports 58 provided on the upper mold hot plate 57, and heated by a heat source (not shown) to solidify the shell sand, and the main mold 61 is formed in the space S.
After manufacturing (FIG. 7), the upper mold heating plate 57 is lifted and taken out. In the figure, reference numerals 59 and 60 denote a pouring spout core and a pouring path core. Further, the main mold 61 of the half-divided body molded as described above.
As shown in FIG. 7, is bonded to a main mold 62 of another half-divided body molded by a sand molding machine (not shown) to be integrated,
Before that, the space recess 63 formed by the Oki core skirting board 55, respectively.
The projecting sand mold 6 is filled in and adhered. That is, the base end portion of the projecting sand mold 6 is preliminarily formed to have the same size as the placement core skirting board 55, and the tip end portion is formed to match the shape of the valley-shaped recess 5 of the cylinder sleeve assembly 1. . Then, when the main molds 61 and 62 are integrally bonded, the cylindrical core 65 is positioned and set in each central cylindrical space, and the molten metal is poured from the pouring port 66 to cast the cylinder sleeve assembly 1.

[0003]

However, in the conventional case, the procedure is such that after the space recess 63 is formed in the main molds 61, 62, the separately molded protruding sand mold 6 is filled and bonded. Management of the mounting position etc. of the storage core skirting board 55 for molding the concave portion 63, for example, dimensional management of L1, L2, L3 etc. of FIG. 6 and dimensions of S1, S2, S3 etc. of the protruding sand mold 6 shown in FIG. There is a problem that precision is required for management, and it is necessary to manage with high accuracy, which causes cost increase. Moreover, there is a problem that such a deviation in accuracy depends on the amount of adhesive applied when the protruding sand mold 6 is bonded to the space recess 63, and that the bonding work requires manpower and man-hours.

[0004]

In order to solve such a problem, the present invention has devised a method for manufacturing a sand mold which can reduce the labor at the time of manufacturing the sand mold and can mold a cylinder sleeve assembly with high accuracy. That is, in the production of a sand mold for forming a cylinder sleeve assembly in which a plurality of sleeves and a connecting portion that connects each sleeve are integrally provided, and a valley-shaped recess is formed around the outer periphery of each connecting portion, The projecting sand mold having the same shape as that of the projecting concave portion was positioned at a predetermined position, and then the main mold was formed around the projecting sand mold, and was integrated with the projecting sand mold when the main mold was formed. Also, a product insert provided in conformity with the outer shape of the cylinder sleeve assembly, a protruding sand mold having the same shape as the valley recess, and a pressing positioning mechanism for pressing and positioning the protruding sand mold in the recess of the product insert. The manufacturing equipment provided was provided.

[0005]

By positioning the projecting sand mold at a predetermined position and then forming a main mold integral with the projecting sand mold around the projecting sand mold, the bonding work process between the two can be omitted and both There is no error in the positional relationship. Further, the protruding sand mold can be easily positioned by pressing the protruding sand mold into close contact with the concave portion of the product insert matching the outer shape of the cylinder sleeve assembly.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a sand mold manufacturing method and apparatus according to the present invention will be described with reference to the accompanying drawings. 1 is a vertical sectional view of a sand mold manufacturing apparatus of the present invention, FIG. 2 is a partially enlarged view of FIG. 1, FIG. 3 is a vertical sectional view of a sand mold, FIG. 4 is a plan view of a cylinder sleeve assembly, and FIG. It is an example of a sand mold.

As described above, the cylinder sleeve assembly 1 shown in FIG. 4 has a plurality of sleeves 2, ..., Which are provided in accordance with the number of cylinders, and a connecting portion 3 for connecting adjacent sleeves 2 and 2.
And a valley-shaped recess 5 formed around the connecting portion 3
An uneven portion 4 for suppressing shrinkage is formed on the outer surface of the.

Therefore, since the complicated uneven portion 4 is formed on the outer surface of the valley-shaped concave portion 5, the convex-concave portion 7 as shown in FIG. 5 is formed.
It is easy to provide the protruding sand mold 6 provided with
It is necessary to shape the shape of the protrusions of the protruding sand mold 6 to match the shape of the valley-shaped recesses 5, and to form the protrusions / recesses 7 in a shape that is the reverse of the shape of the uneven portions 4. By the way, the convex / concave portion 7 is, for example, a groove 7a for forming a protruding rib along the circumferential direction of the sleeve 2, a plurality of hole portions 7b for forming a point-like protruding portion, etc. Consists of.

Therefore, as shown in FIG. 1, the sand mold manufacturing apparatus 10 of the present invention comprises a product insert 13 attached to a lower plate 11 with bolts 12 and a plurality of pressing and positioning mechanisms 15 capable of moving up and down. The hot plate 14 is provided, and the protruding sand mold 6 is positioned by the pressing and positioning mechanism 15 so that an integral sand mold can be manufactured.

That is, the product insert 13 is made according to the outer shape of the cylinder sleeve assembly 1, and
A pouring passage core 16 and a pouring spout core 17 are positioned and fixed to one end of the product insert 13, and key members 18 are fixed to the both ends of the lower plate 11 by bolts 19.

As shown in FIG. 2, the pressing and positioning mechanism 15 is a cylindrical guide member 21 which is inserted into a through hole 14a formed in the upper mold heat plate 14 and has its lower end portion extended downward.
And a pressing pin 22 slidable up and down in the cylinder of the guide member 21, and a fixing member 23 fixed by a screw 25 to the upper mold heat plate 14 for fixing the guide member 21 irremovably. The compression spring 2 is provided between the fixing member 23 and the pressing pin 22.
4 is installed.

The lower end portion of the guide member 21 and the lower end portion of the pressing pin 22 respectively have tapered portions 21.
a and 22a are provided.

By the way, on the back side of the projecting sand mold 6,
The tapered portions 21a of the guide member 21 and the pressing pin 22,
22a is provided with a stepped taper hole 6a. The taper hole 6a is 1 in the embodiment.
Two protruding sand molds 6 are provided at two locations along the longitudinal direction, and the pressing positioning mechanism 15 is provided corresponding to each tapered hole 6a. That is, the press positioning mechanism 15
2 are provided in the direction perpendicular to the paper surface of FIG. 1, and a total of 6 are provided.

Further, a plurality of sand pouring ports 26 are provided at predetermined positions of the upper mold hot plate 14, and when the upper mold hot plate 14 is lowered, a main mold is provided between the product insert 13 and the upper mold hot plate 14. A space S for molding is formed.

In the sand mold manufacturing apparatus 10 thus constructed, the projecting sand mold 6 is set in the recess of the product insert 13.
When the upper mold hot plate 14 is lowered, the pressing pins 22 of each pressing and positioning mechanism 15 and the tips of the guide members 21 enter the respective tapered holes 6a of the projecting sand mold 6, and the projecting sand mold 6 is inserted into the product by the compression spring 24. It is made to adhere while pressing on 13. That is, both are surely aligned.

Next, after shell sand is poured from a plurality of sand pouring ports 26 to fill the space S, the shell sand is solidified by heating by a heat source (not shown) of the upper mold heating plate 14 and has the same shape as the space S. The master mold 30 (FIG. 3) is molded. Moreover, at this time, the main mold 30 and the protruding sand mold 6 are integrally molded.

The upper mold heating plate 14 is raised to raise the protruding sand mold 6
When the main mold 30 integrated with is taken out, holes are formed in the main mold 30 and the protruding sand mold 6 where the guide member 21 and the pressing pin 22 are removed. It has no effect.

Further, in the sand mold molding as described above, a recess 31 as shown in FIG. 3 is formed at a portion corresponding to the key member 18, but the configuration other than the key member 18 is the same but not shown. The main mold 32 manufactured by the manufacturing apparatus is provided with the protrusion 33 at a corresponding position.

Then, the pair of main molds 30 and 32 are aligned and bonded as shown in FIG. 3, and the cylindrical cores 34 are positioned and set in the central spaces, respectively, and the molten metal is poured from the pouring port 35. The cylinder sleeve assembly 1 is cast.

At this time, when the main mold 30 is molded, the projecting sand mold 6 is accurately integrated by the pressing and positioning mechanism 15, so that the casting accuracy of the cylinder sleeve assembly 1 can be improved.

[0021]

As described above, according to the present invention, the projecting sand mold and the main mold are separately molded and then the two are bonded to each other, but the projecting sand mold is integrally molded at the time of molding the main mold. As a result, the bonding work becomes unnecessary, which not only leads to a reduction in the number of steps such as an adhesive coating step and a bonding step, but also leads to a reduction in the cost of the adhesive and the like and further improves the accuracy of the sand mold.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a sand mold manufacturing apparatus of the present invention.

FIG. 2 is a partially enlarged view of FIG.

[Fig. 3] Cross-sectional view of the assembled sand mold

FIG. 4 is a plan view of a cylinder sleeve assembly.

FIG. 5 is an example of a protruding sand mold, in which (a) is a perspective view and (b) is a sectional view.

FIG. 6 is a vertical sectional view of a conventional sand mold manufacturing apparatus.

FIG. 7 is a plan view of a conventional assembled sand mold.

[Explanation of Codes] 1 cylinder sleeve assembly 2 sleeve 3 connecting part 5 valley recess 6 protruding sand mold 10 sand mold manufacturing device 13 product insert 15 press positioning mechanism 30 main mold

Claims (2)

[Claims] 1. A sand mold for forming a cylinder sleeve assembly, which integrally comprises a plurality of sleeves and a connecting portion for connecting the respective sleeves, and a valley-shaped recess is formed around the outer periphery of each connecting portion. In this method, this method comprises positioning a protruding sand mold having the same shape as the valley recess at a predetermined position, then forming a main mold around the protruding sand mold, and forming the protruding sand mold at the time of forming the main mold. A method for manufacturing a sand mold for molding a cylinder sleeve aggregate, which is characterized by being integrated. 2. A sand mold for molding a cylinder sleeve assembly, which integrally comprises a plurality of sleeves and a connecting portion for connecting the respective sleeves, and a valley-shaped recess is formed around the outer periphery of each connecting portion. In this device, the device comprises a product insert provided in conformity with the outer shape of the cylinder sleeve assembly, a projecting sand mold having the same shape as the valley recess, and the projecting sand mold used as a recess of the product insert. An apparatus for manufacturing a sand mold for molding a cylinder sleeve assembly, comprising a pressing and positioning mechanism for pressing and positioning.