JP2825433B2 - Aluminum casting mold with cast pins - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum casting mold provided with a cast pin used for casting aluminum.

[0002]

2. Description of the Related Art When casting aluminum, the molten aluminum is extremely active. Therefore, when the casting cycle is continuously performed with the molten aluminum alloy, the cast pins are subjected to chemical erosion or welding due to contact, resulting in erosion. This causes breakage due to welding and galling with the cast product due to welding. Therefore, as shown in FIG.
It is known that a gradient of about 1/50 is formed in one draft slope portion 101a to improve releasability from a cast product.

[0003]

When a gradient of about 1/50 is formed as in the above-described conventional aluminum casting pin, for example, in order to cut a rolled screw, a pilot hole having a predetermined tolerance is formed. Drilling is required, which increases man-hours. Further, since it is fixed to the movable mold 100, a gap is formed between the movable mold 100 and the fixed mold 102, and film burrs are generated there.

[0004]

Casting mold according to the present invention to solve the above problems SUMMARY OF THE INVENTION are movable mold and aluminum casting mold having a punching pin cast in at least one of the fixed mold
There are, the core pin has a draft angle portion with having a corrosion resistance to molten aluminum, the draft unit slope is 1 / 300-1 / 1000, and the small diameter portion of the draft part Al diameter of diameter and large-diameter portion having a dimension and the core pin that fits within the tolerance of the diameter of the prepared hole to be formed originally
In the minium casting mold, the cast pin is
It is inserted so that it can advance and retreat in the axial direction, and the base
Bolt in the direction, and set the bolt head in the movable mold
The neck is inserted into and supported by the support member that has been
An elastic member is interposed between the punching pin and the base of the punching pin.
Pin in the direction of the fixed mold so that the
The movable part is fixed by the urging of the elastic member.
The mold was brought into close contact with the mold in the closed state.

[0005]

[Action] The draft angle of the cast pin is 1/300 to 1/10.
Since the small diameter portion and the large diameter portion of the draft portion are formed within the tolerance of the prepared hole, the prepared hole can be omitted and the screw processing can be performed. In particular, casting
The punch pin is moved through an elastic member that allows axial displacement.
The fixed mold and the movable mold are tightened by attaching to the mold.
The tip of the cast pin contacts the fixed mold in the
When the molten metal is poured, the cast pin and the mold
Due to the difference in expansion coefficient from
A gap is created between the tip of the punch pin and the fixed mold, causing film burrs.
Can be prevented.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an aluminum casting mold cross-section view according to a reference example of the present invention, FIG 2 is a side view of the core pin is applied to the aluminum casting mold according to a reference example of the present invention, FIG. 3 It is principal part sectional drawing of the metal mold | die for aluminum casting which concerns on this invention.

The aluminum casting mold comprises a fixed mold 1 and a movable mold 2, and the fixed mold 1 and the movable mold 2 are fixed to holders 3 and 4, respectively. A cast pin 10 is inserted into the fixed mold 1 and the movable mold 2 so as to be able to advance and retreat, and a rear end of the cast pin 10 is fixedly connected to the connecting plate 5. The cylinder 6 is provided so that it can move forward and backward.

A push pin 7 is inserted into the movable die 2 so as to be able to advance and retreat, and the rear end of the push pin 7 is fixedly connected to a connecting plate 8 so as to be advanced and retracted by a hydraulic cylinder (not shown).

Here, the cast pin 1 for aluminum casting is used.
0, the draft portion 10a is provided in the first half as shown in FIG. 2, and the draft of the draft portion 10a is 1/300 to 1
/ 1000, and the diameter (d) of the small diameter portion at the tip of the draft portion 10a is set to fall within a dimension obtained by subtracting a tolerance from the diameter of the pilot hole to be formed.
The diameter (D) of the large-diameter portion at the base end of a is set to be within a dimension obtained by adding a tolerance to the diameter of the pilot hole to be originally formed. More specifically, when the draft pin 10 is formed so that the draft angle of the cast pin 10 becomes 1/550 and, for example, a M8 screw hole is cut, the total length L of the hole is 28 mm because the tolerance of the prepared hole is 0.15 mm. , The diameter D of the large diameter side of the cast pin 10 is φ7.35 mm,
The diameter d on the small diameter side is set to φ7.25 mm so that M8 can be threaded without post-processing by a drill.

The cast pin 10 is formed of a material having corrosion resistance to molten aluminum or a material coated with a material having corrosion resistance, for example, a pin made of titanium material is subjected to nitriding treatment to form a hardened surface layer. What did
Alternatively, a steel pin surface coated with a hard carbon film or the like is used to minimize the welding of molten aluminum during casting to prevent galling with the cast product during mold release.

Here, a cast pin 1 made of a titanium alloy is used.
0 is, for example, using a titanium alloy of Ti-6Al-4V, forming a cast pin in the shape shown in FIG. 2, and then performing a nitriding treatment at a temperature of 850 ° C. to 900 ° C. for 48 hours in a nitriding furnace. Vickers hardness 200 on the surface of the punch pin 10
It can be obtained by forming a nitride layer (titanium nitride) having a thickness of 5 to 6 μm with a thickness of 0 or more. When a cast pin having a nitrided layer formed on the surface of such a titanium material is used, the affinity between the nitrided layer and the molten aluminum is poor, so that the melt wettability is reduced, and the alloy layer of titanium and aluminum is formed. It is difficult to grow, and the erosion of the cast pin is prevented, so that damage and deterioration of releasability can be prevented.

The formation of the cast pin 10 in which the surface of a steel pin is covered with a hard carbon film is performed, for example, by using hot tool steel (JI
S SKD61) can be obtained by coating a hard carbon film having a thickness of 0.5 to 5 mm by a plasma CVD method, which is a typical low-temperature CVD method. Here, as the raw material gas,
A hydrocarbon gas diluted with hydrogen gas is suitable, and an Ar gas can also be introduced. In this case, charcoal,
An intermediate layer of a nitride ceramic or the like can also be formed.

FIG. 3 is a sectional view of a main part of an aluminum casting mold according to the present invention . The mold comprises a fixed mold 1 and a movable mold 2 as described above. A bolt 13 is screwed in the axial direction on the base portion 10b of the cast pin 10, and is inserted into the movable mold 2 so as to be able to advance and retreat.
A spring 15 as an elastic member is provided between the support member 14 attached to the movable mold 2 and the back of the base 10b of the blanking pin 10.
Of the cast pin 10
Is biased in the protruding direction so that the cast pin 10 can advance and retreat within the range of the cushion stroke T.

Here, the load applied by the spring 15 to the blanking pin 10 is set to, for example, 320 to 380 kg / cm ² so that the cushion stroke T becomes 1 to 1.5 mm. The range of given El load or cushion stroke T is not limited to the above.

By attaching the blanking pin 10 to the movable die 2 of the mold via the elastic member which allows displacement in the axial direction as described above, the fixed molding die 1 and the movable mold 2 are tightened and the blanking pin 10 is fixed. Is in close contact with the fixed mold 1 . This state
When the molten aluminum 16 is poured, a gap is formed between the tip of the casting pin 10 and the fixed mold 1 due to a difference in expansion coefficient between the casting pin 10 and the mold, the dimensional accuracy of the casting pin 10, and the like. This can prevent film burrs from occurring.

In the above-described case of performing aluminum casting, the fixed mold 1 and the movable mold 2 are clamped to inject molten aluminum, and when the aluminum solidifies, the hydraulic cylinder 6 of the fixed mold 1 is operated to connect. After the casting pin 10 is retracted through the plate 5 and pulled out of the work (cast product) W, the movable mold 2 is retracted and the mold is opened. And movable mold 2
The hydraulic cylinder 6 is operated to retract the casting pin 10 through the connecting plate 5 and pull out the work W, and then the pushing pin 7 is advanced through the connecting plate 8 to move the work W into the movable mold 2.
Extrude from

As described above, by removing the cast pin from the cast product before opening the mold and before extruding the cast product, it is possible to make the draft angle extremely small, and to cut the rolled screw without drilling the pilot hole. be able to.

[0018]

As described above, according to the first aspect of the present invention,
In the bright, pin punching cast in one also less of the movable mold and the stationary mold
Aluminum casting mold with
Has corrosion resistance to molten aluminum and
The draft portion has a gradient of 1/300 to
1/1000, and the diameter and large diameter of the small diameter part of the draft part
The diameter of the diameter part is within the tolerance of the diameter of the pilot hole to be originally formed
Aluminum casting mold with cast pins
The cast pin is inserted into the movable mold so that it can move back and forth in the axial direction.
Through which the bolt is axially connected to the base of the cast pin
Then, the head of the bolt is attached to the support member provided in the movable mold by the neck.
Inserted and supported, between the support member and the base of the blanking pin
An elastic member is interposed between them, and the cast pin is moved in the direction of the fixed mold.
Energize it so that it protrudes, and push the tip of the
Due to the urging of the material, the tightness of the movable and fixed molds is maintained.
Since the cause, it forms a gradient of draft parts of the core pin to 1 / 300-1 / 1000, and the dimension of the small diameter portion and the large diameter portion of the draft part falls within the tolerance of the prepared hole and
That is, when a rolled screw is cut in a cast product, a pilot hole having a predetermined tolerance can be obtained without performing a pilot hole process, and the number of processing steps for the rolled screw is reduced.

In particular, in the present invention, the cast pin is formed into a movable mold.
It is inserted so that it can advance and retreat in the axial direction, and the base
Bolt in the direction, and set the bolt head in the movable mold
The neck is inserted into and supported by the support member that has been
An elastic member is interposed between the punching pin and the base of the punching pin.
Pin in the direction of the fixed mold so that the
Of the movable type and the fixed type by urging the elastic member.
Fixed and movable as it is in close contact with the mold
When the mold is tightened, the tip of the cast pin comes into close contact with the fixed mold
In this state, the molten aluminum is poured.
The difference between the expansion coefficient of the die and the die,
Depending on the pin dimensional accuracy, etc.
To prevent film burrs from forming
Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view of an aluminum casting mold according to a reference example of the present invention.

FIG. 2 is a side view of a cast pin applied to an aluminum casting mold according to a reference example of the present invention.

FIG. 3 is a sectional view of a main part of an aluminum casting mold according to the present invention .

FIG. 4 is a view showing the shape of a conventional cast pin.

[Explanation of symbols]

1: fixed type, 2: movable type, 10: cast pin, 13: bo
14, support member, 15 ... elastic member (spring
G)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-87053 (JP, A) Japanese Utility Model Application Hei 5-78357 (JP, U) Japanese Utility Model Application Hei 3-69307 (JP, U) Japanese Utility Model Application Hei 2- 28356 (JP, U) Jikai 4-113144 (JP, U) Casting, 60 [12] (1988) Japan Foundry Association, p. 747-751 (58) Field surveyed (Int. Cl. ⁶ , DB name) B22D 17/22 B22C 9/00

Claims (1)

(57) [Claims] 1. An aluminum casting mold having at least one of a movable die and a fixed die having a cast pin , wherein the cast pin has corrosion resistance to molten aluminum and has a draft portion. , The slope of this draft section is 1
/ 300-1 / 1000 and, and aluminum diameter of diameter and large diameter portion of the small diameter portion is provided with a pin punching cast and sized to fit within the tolerance of the diameter of the prepared hole to be formed originally draft section casting
In the molding die, the cast pin is inserted into the movable die so as to be able to advance and retreat in the axial direction.
A bolt is axially connected to the base of the blanking pin,
Insert the neck part into the support member with the bolt head inside the movable mold
Supporting Te, elastic members between the support member and the base of the core pin
So that the cast pin protrudes in the direction of the fixed mold.
And the tip of the cast pin is biased by the elastic member.
The movable and fixed molds in close contact.
An aluminum casting mold provided with a cast pin.