Die casting mold for forming inclined hole in cylinder block

Abstract

Disclosed herein is a die casting mold for forming an inclined hole in a cylinder block, in which a core pin forming the inclined hole is installed at a position that does not interfere with a sleeve used as a molten-metal injecting passage in the die casting mold.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority of Korean Patent Application Serial Number 10-2006-0096053 filed on Sep. 29, 2006 with the Korean Intellectual Property Office, the disclosure of which is hereby incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention relates generally to a die casting mold for forming an inclined hole in a cylinder block and, more particularly, to a die casting mold for a cylinder block, in which an inclined-hole machining unit is installed such that there is no interference between the unit and a molten-metal injecting sleeve.

BACKGROUND OF THE INVENTION

Generally, a cylinder block of an engine is manufactured through a casting method using a cast iron. In order to achieve the lightness of the engine, the cylinder block has been produced through a low-pressure casting method from aluminum.

However, the cylinder block produced through the low-pressure casting method is problematic in that the production is limited to small quantities. Thus, recently, a new manufacturing method, called die casting for high-pressure casting, has been used. One example of cylinder blocks 1 manufactured through the new method is illustrated in FIG. 1.

A cylinder block 1 manufactured through casting must be provided with various flow passages corresponding to an oil flow path and a coolant flow path. The flow passages are formed by a core pin installed in a mold during casting.

Thus, when the core pin is installed in the mold during the casting, the core pin must be arranged at a proper position and in a proper direction, in consideration of several aspects, including the moving direction of the mold and the injection direction of the molten metal.

However, among various flow passages formed in the cylinder block, an inclined hole 1b cannot be formed by installing the core pin in the die casting mold. As shown in FIG. 2, the inclined hole 1b is formed in a skirt 1a in a center of the cylinder block 1, with an oil filter being mounted to the inclined hole 1b. The reason why the inclined hole 1b cannot be formed by the core pin is because the portion where the inclined hole 1b is formed structurally interferes with a sleeve defining a molten-metal injecting path.

That is, in the cylinder block 1 produced through the conventional die casting mold, the inclined hole 1b provided in the skirt 1a is formed by the core pin installed in the die casting mold. In this case, the installed position of an actuator, which pushes the core pin in the mold during the casting and removes the core pin from the mold after the casting process has been completed and before the mold is removed, overlaps the position of the molten-metal injecting sleeve in the die casting mold, thus causing interference between the actuator and the sleeve. For this reason, it is impossible to install the core pin for forming the inclined hole 1b in the die casting mold.

Consequently, an additional process is required to follow the completion of the die casting in order to form the inclined hole 1b in the skirt 1a of the cylinder block 1. In the cylinder block 1, the inclined hole 1b, used to mount the oil filter, is formed at a portion at which material is thick. Thus, due to the difference in contraction ratio when respective parts are cooled during the casting, air bubbles can be formed in the material. The thus-produced air bubbles undesirably may become an oil leakage path, which can in turn deteriorate the engine lubricating capacity.

Further, the inclined hole 1b formed in the skirt 1a of the cylinder block 1 is relatively long, thus causing damage to a machining tool, such as a drill, that would be used to form the inclined hole 1b after the casting process is completed.

There is thus a need for an improved die casting mold in which a core pin forming an inclined hole is installed at a position that does not interfere with a sleeve used as a molten-metal injecting passage in the die casting mold.

The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known to a person skilled in the art.

SUMMARY OF THE INVENTION

The present invention provides an improved die casting mold that overcomes the problems associated with conventional die casting molds. According to the present invention, a die casting mold is provided in which a core pin forming an inclined hole for mounting an oil filter is installed at a position that does not interfere with a sleeve used as a molten-metal injecting passage in the die casting mold, thereby affording mass production of the cylinder block through high-pressure casting, and allowing the inclined hole to be integrally formed during the casting.

In one aspect, the present invention provides a die casting mold for forming an inclined hole in a cylinder block, which has a fixed mold, a movable mold movably mounted to the fixed mold, and a sleeve for injecting molten metal into the molds so as to manufacture the cylinder block through high-pressure casting, the fixed mold comprising a moving space that comprise: (a) a first space including a core pin for forming a flow passage in the cylinder block during casting; and (b) a second space including an actuator. In such die casting mold, the first moving space is placed above the sleeve so as to avoid interference with the actuator and the sleeve.

Preferably, one side of the second space may be defined to the left side of the sleeve and the other side of the second space may be defined to the right side of the sleeve.

Also preferably, the core pin may be mounted to a movable member installed in the first space.

The movable member of the first space may be suitably designed to reciprocate the actuators each of which is defined in each side of the second space.

In other aspect, the present invention provides a die casting mold for forming an inclined hole in a cylinder block, which has a fixed mold, a movable mold movably mounted to the fixed mold, and a sleeve for injecting molten metal into the molds so as to manufacture the cylinder block through high-pressure casting, the die casting mold comprising (a) a moving space and (b) an inclined-hole machining unit.

A moving space is defined in the fixed mold. The moving space has a first space defined above the sleeve so as to avoid interference with the sleeve, and a second space defined on each of the left and right sides of the sleeve.

An inclined-hole machining unit is provided in the moving space, and forms an inclined flow passage in the cylinder block during casting. The inclined-hole machining unit includes a movable member movably installed in the first space, a core pin mounted to the movable member and forming the flow passage in the cylinder block, and an actuator provided on each side of the second space to reciprocate the movable member.

Preferably, the fixed mold may comprise a guide hole to guide the insertion of the core pin. In one preferred embodiment, the guide hole may receive a hollow pin-type bushing so as to prevent damage to material from the core pin. Further, an inlet of the guide hole may suitably be provided with a hollow fastening member to prevent removal of the pin-type bushing.

A preferred embodiment of the present invention may further comprise a guide rod installed in the second space to guide movement of the movable member. In such embodiment, a first end of the guide rod may be connected to the actuator of the second space and a second end of the guide rod may be installed in the first space along the moving direction of the movable member. Preferably, the guide rod may be installed to penetrate both ends of the movable member. Also preferably, the movable member may have at each of its side ends a first through hole for mounting the guide rod, with a mounting bushing being installed in the first through hole to reduce friction between the first through hole and the guide rod. Furthermore, the movable member may have in its center a second through hole for mounting the core pin, the core pin integrally may have at its one end a flange which is seated and supported on an inlet of the second through hole, and a removal prevention plate may be coupled to the back side of the flange to prevent the core pin from being removed from the second through hole.

In another preferred embodiment, the actuator may suitably comprise a piston rod coupled to each of opposite ends of the movable member to reciprocate the movable member in the first space.

In a further aspect, motor vehicles are provided that comprise a described die casting mold.

It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like. The present die casting mold will be particularly useful with a wide variety of motor vehicles.

Other aspects of the invention are discussed infra.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the nature and objects of the present invention, reference should be made to the following detailed description with the accompanying drawings, in which:

FIG. 1 is a view illustrating a general cylinder block;

FIG. 2 is a sectional view illustrating an inclined hole formed in a skirt of FIG. 1;

FIG. 3 is a view schematically illustrating the construction of a die casting mold for forming an inclined hole in a cylinder block according to a preferred embodiment of the present invention;

FIG. 4 is a vertical sectional view illustrating a fixed mold of FIG. 3;

FIG. 5 is a view schematically illustrating the arrangement between a sleeve of FIG. 4 and an inclined-hole machining unit according to a preferred embodiment of the present invention;

FIG. 6 is a view illustrating the rear construction of the sleeve of FIG. 4;

FIG. 7 is a view illustrating the states before and after the inclined-hole machining unit of FIG. 5 is operated;

FIG. 8 is a perspective view illustrating front and rear sides of a movable member of FIG. 5; and

FIG. 9 is a view illustrating a mounting bushing of FIG. 5.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiment of the present invention, examples of which are illustrated in the drawings attached hereinafter, wherein like reference numerals refer to like elements throughout. The embodiments are described below so as to explain the present invention by referring to the figures.

As shown in the drawings, a die casting mold for manufacturing a cylinder block (see, FIG. 1) through high-pressure casting includes a fixed mold 10 and a movable mold 12 which is movably mounted to the fixed mold 10. A cavity corresponding to the appearance of the cylinder block is provided between the fixed mold 10 and the movable mold 12.

A sleeve 14, corresponding to the passage for injecting molten metal into the mold, is provided in the fixed mold 10. A plunger (not shown) is installed in the sleeve 14 to deliver the molten metal into the mold.

A moving space 16 is provided in the fixed mold 10, and is used for avoiding the interference with the sleeve 14. An inclined-hole machining unit is installed in the moving space 16, and forms the inclined flow passage in the cylinder block during the casting.

To this end, the moving space 16 includes a first space 16a and a second space 16b. The first space 16a is defined above the sleeve 14 in the fixed mold 10 to avoid interference with the sleeve 14. The second space 16b is defined in opposite sides of the sleeve 14 in the fixed mold 10.

The inclined-hole machining unit includes a movable member 18, a core pin 30, and actuators 20. The movable member 18 is movably installed in the first space 16a of the moving space 16. The core pin 30 is mounted to the center of the movable member 18, and functions to form the inclined hole which is the inclined flow passage defined in the cylinder block. Each actuator 20 is installed in the corresponding second space 16b of the moving space 16, and functions to reciprocate the movable member 18 when the casting process is performed and completed.

A hollow guide hole is formed in the fixed mold 10, and functions to guide the core pin 30 when the core pin 30 is inserted into the mold. A hollow pin-type bushing 10a is installed in the guide hole, and prevents damage to a material from the core pin 30. Further, a hollow fastening member 10b is fastened to an inlet of the guide hole in order to prevent the removal of the pin-type bushing 10a.

A guide rod 22 is provided for guiding the movement of the movable member 18. One end of the guide rod 22 is secured to the actuator 20, while the other end of the guide rod 22 is installed, along the moving direction of the movable member 18, in the first space 16a of the moving space 16.

The guide rod 22 is installed to penetrate through the movable member 18. First through holes 18a are formed in both sides of the movable member 18 so that each guide rod 22 is inserted into the corresponding first through hole 18a. A hollow mounting bushing 24 is provided in each of the first through holes 18a to reduce the friction between each of the guide rod 22 and the first through hole 18a.

Further, a second through hole 18b is formed in the center of the movable member 18 so that the core pin 30 is inserted into the second through hole 18b. A flange 30a is integrally provided at one end of the core pin 30, and is seated in a concave seat 18c which is provided around the inlet of the second through hole 18b. A removal prevention plate 26 is coupled to the back of the flange 30a to prevent the core pin 30 from being removed from the second through hole 18b.

Further, third through holes 18d are formed at both ends of the movable member 18 so as to install piston rods 20a.

Moreover, a chamfer 18e is provided on the central portion of the bottom of the movable member 18 so that the movable member 18 does not interfere with the upper end of the sleeve 14, because the movable member 18 is arranged such that the installation direction thereof is slightly inclined relative to the installation direction of the sleeve 14. The forming angle or area of the chamfer 18e may be appropriately determined within a range that can prevent interference between the movable member 18 and the sleeve 14 in the fixed mold 10.

The actuators 20 are provided with the piston rods 20a which are coupled to both ends of the movable member 18, and reciprocate the movable member 18 in the moving space 16. In this case, the actuators 20 reciprocate the movable member 18 in a vertical direction in the first space 16a of the moving space 16 via operating pressure supplied from the exterior.

To this end, pressure pipes 20b are provided on the actuators 20 to be coupled to an external operating-pressure supply source.

Hereinafter, the operation of the present invention will be described in detail.

The die casting is started in the state where the fixed mold 10 and the movable mold 12 are coupled to each other. First, the molten metal is injected through the sleeve 14 provided in the fixed mold 10.

At this time, the core pin 30 enters the cast product formed between the fixed mold 10 and the movable mold 12, so that the inclined flow passage may be formed in the cylinder block after the casting has been completed.

That is, in the moving space 16 defined in the fixed mold 10, the movable member 18 is moved up along the first space 16a by piston rods 20a which are to be extended by the operation of the actuators 20. The core pin 30 coupled to the movable member 18 is simultaneously moved up and enters the cast product through the guide hole 10a defined in the fixed mold 10.

The movable member 18, moving up and down in the first space 16a, can be guided to a predetermined position by the guide rods 22. Thus, the core pin 30 can enter the correct position in the cast product through the guide hole 10a which is defined in the fixed mold 10.

Afterwards, when the injection of the molten metal through the sleeve 14 is completed, the actuators 20 perform restoring action so that the movable member 18 can move downwards to return to an original position thereof. At this time, the core pin 30 that has entered the cast product moves from the interior of the cast product into the guide hole 10a of the fixed mold 10.

As apparent from the foregoing, the present invention has an advantage that a machining unit for forming an inclined hole when a cylinder block is die-cast can be installed in a mold so as to not interfere with a molten-metal injecting sleeve provided in a fixed mold, thereby allowing the inclined hole to be formed at the same time as the cylinder block is cast.

Consequently, the present invention can avoid the formation of air bubbles that would otherwise be caused by a difference in contraction ratio due to the cooling of the cast at a thick portion forming the inclined hole. Since the inclined hole is formed when the cylinder block is cast, the present invention does not cause a problem of damaging the tools used for machining the inclined hole, which could occur when an inclined hole is formed after casting has been completed.

Further, as a core pin for forming the inclined hole can be inserted into the fixed mold before the molds are separated from each other to remove a cast product, damage to the inclined hole can also be prevented.

The invention has been described in detail with reference to preferred embodiments thereof. However, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A die casting mold for forming an inclined hole in a cylinder block, which has a fixed mold, a movable mold movably mounted to the fixed mold, and a sleeve for injecting molten metal into the molds so as to manufacture the cylinder block through high-pressure casting, wherein the fixed mold includes a moving space comprising:

a first space including a core pin for forming a flow passage in the cylinder block during casting; and

a second space including an actuator, wherein the first moving space is placed above the sleeve so as to avoid interference with the actuator and the sleeve.

2. The die casting mold as defined in claim 1, wherein one side of the second space is defined to the left side of the sleeve and the other side of the second space is defined to the right side of the sleeve.

3. The die casting mold as defined in claim 2, wherein the core pin is mounted to a movable member installed in the first space.

4. The die casting mold as defined in claim 3, wherein the movable member of the first space reciprocates the actuators each of which is defined in each side of the second space.

5. A die casting mold for forming an inclined hole in a cylinder block, which has a fixed mold, a movable mold movably mounted to the fixed mold, and a sleeve for injecting molten metal into the molds so as to manufacture the cylinder block through high-pressure casting, the die casting mold comprising:

a moving space defined in the fixed mold, and having a first space defined above the sleeve so as to avoid interference with the sleeve and a second space defined on each of the left and right sides of the sleeve; and

an inclined-hole machining unit provided in the moving space, and forming an inclined flow passage in the cylinder block during casting, wherein the inclined-hole machining unit comprises: a movable member movably installed in the first space; a core pin mounted to the movable member, and forming the flow passage in the cylinder block; and an actuator provided on each side of the second space to reciprocate the movable member.

6. The die casting mold as defined in claim 5, wherein the fixed mold comprises a guide hole to guide the insertion of the core pin.

7. The die casting mold as defined in claim 6, wherein the guide hole receives a hollow pin-type bushing so as to prevent damage to material from the core pin.

8. The die casting mold as defined in claim 7, wherein an inlet of the guide hole is provided with a hollow fastening member to prevent removal of the pin-type bushing.

9. The die casting mold as defined in claim 5, further comprising a guide rod installed in the second space to guide movement of the movable member.

10. The die casting mold as defined in claim 9, wherein a first end of the guide rod is connected to the actuator of the second space and a second end of the guide rod is installed in the first space along the moving direction of the movable member.

11. The die casting mold as defined in claim 10, wherein the guide rod is installed to penetrate both ends of the movable member.

12. The die casting mold as defined in claim 11, wherein the movable member has at each of its side ends a first through hole for mounting the guide rod, with a mounting bushing being installed in the first through hole to reduce friction between the first through hole and the guide rod.

13. The die casting mold as defined in claim 11, wherein the movable member has in its center a second through hole for mounting the core pin, the core pin integrally has at its one end a flange which is seated and supported on an inlet of the second through hole, and a removal prevention plate is coupled to the back side of the flange to prevent the core pin from being removed from the second through hole.

14. The die casting mold as defined in claim 5, wherein the actuator comprises a piston rod coupled to each of opposite ends of the movable-member to reciprocate the movable member in the first space.

15. A vehicle comprising the die casting mold of claim 1.

16. A vehicle comprising the die casting mold of claim 5.