JP3237061B2 - Core for casting in casting equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting apparatus for performing a series of steps of supplying a molding material, plasticizing a molding material by heating, injecting a molten material into a mold, cooling and solidifying, and taking out a product. The present invention relates to a core for casting used. The core for casting is inserted and arranged in a mold, and is necessary when forming a concave portion such as a hole or a groove by casting.When removing a cast product from the mold, the core is a product. The core is further drawn out, whereby a concave portion such as a hole, a groove or the like corresponding to the core shape is cast-formed in the product.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional casting apparatus including a core for casting. Reference numeral 10 denotes a fixed matrix which is fixed to a base body of a casting apparatus (not shown), and a fixed insert 11 is fixedly arranged on the opposite end face side of the fixed mold 10, and the fixed insert 11 is opposed to the fixed insert. The female mold 11A corresponding to the outer shape on one side of the product W is engraved toward the end face. Reference numeral 12 denotes a movable mother die which is attached to a movable device provided on the base body and is movable toward and away from the fixed mother die 10, and a movable insert 13 is fixed to the end face side of the movable mother die 12. The female mold 13A corresponding to the outer shape of the other side of the product W is engraved toward the facing end face of the movable side insert 13. 14 is
This is a core for casting that is arranged facing the female mold 13A of the movable insert 13 and the female mold 11A of the fixed insert 11.
The core 14 is formed of an iron-based material (for example, SKD61), and a product equivalent portion 14A corresponding to a product portion (cast hole) is formed at the tip thereof. 14A
The holder portion 14B is provided continuously from the rear end portion. The holder 14B of the core 14 is the core holder 1
5 is sandwiched between a fixed matrix 10 including a fixed side insert 11 and a movable matrix 12 including a movable side insert 13.
A slide pin holder 16 is disposed at the rear end of the core holder 15, and is fixed in a slide pin guide hole 16 </ b> A formed in the slide pin holder 16 while being inclined with respect to the fixed matrix 10. The arranged inclined slide pins 17 are slidably guided and arranged. The state shown in FIG. 5 shows the female mold 11A of the fixed side insert 11 and the movable side insert 13
Shows the injection end state in which the molding material has been injected into the cavity formed by the female mold 13A and the product equivalent portion 14A of the core 14. From this state, the product W is taken out through cooling and solidification. According to the above description, the product W has an outer shape along the female mold 11A of the fixed-side insert 11 and the female mold 13A of the movable-side insert 13 and a cast hole W1 along the product equivalent portion 14A of the core 14. Are formed.

[0003]

According to the molding of the product W in such a conventional casting apparatus, the cast hole W1 is a tapered hole having a large mouth diameter (φD1) and a small bottom diameter (φD2). The reason why the cast hole W1 is a tapered hole is as follows. That is, iron core 14
For example, when a molten metal material such as aluminum is injected into a cavity, the core 14 rises to a casting temperature and expands, and then the core 14 contracts due to a temperature decrease due to cooling and solidification. Here, when the thermal expansion of aluminum forming the product W and the iron forming the core 14 are compared, since the thermal expansion of iron is smaller than the thermal expansion of aluminum, cooling and solidification have been completed. When the product-equivalent portion 14A of the core 14 is pulled out from the product W, the cast-out hole W1 formed of aluminum shrinks greatly and the product-equivalent portion 14A of the core 14
And the core 14 is difficult to pull out from the product W. Therefore, in order to easily pull out the core 14 from the product W, the mouth diameter (φD1) is large and the bottom diameter (φD1) is large.
D2) must be formed in the tapered core 14 having a draft with a small diameter.

[0004] Referring to FIG. 2, at a product take-out temperature of 300 ° C., a holding force corresponding to A (mm) is applied to the product equivalent portion 14 A of the core 14.

The draft varies depending on the material of the product. The draft is 1 ° to 3 ° for aluminum, the draft is 0 ° 30 'to 2 ° for zinc, and the draft for magnesium. Requires a draft of 1 ° to 3 °. This is because each material has a different thermal expansion amount.

According to the above description, the cast hole W1 is always formed as a tapered hole, and as the depth of the cast hole W1 increases, the difference between the mouth diameter and the bottom diameter increases. When required, post-processing such as cutting is necessarily required. Therefore, the manufacturing cost by post-processing increases, and there is a problem that an inexpensive product cannot be provided.

[0007] The core for casting in the casting apparatus according to the present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a cast hole having a straight hole with no draft.

[0008]

According to the present invention, there is provided a core for casting in a casting apparatus according to the present invention, wherein the core is a core for casting used in a casting apparatus for forming a product. Is formed from a metal material and a thin bag hole is provided inside a product equivalent portion corresponding to at least the product portion of the core, and in the thin bag hole, in a range of a product take-out temperature to a product pouring temperature. A first feature is that a metal material which is in a molten state and solidifies in a temperature range for taking out a product is hermetically sealed.

According to the present invention, in addition to the first feature, a spacer collar insertion hole and a thin-walled bag hole are continuously provided inside the core from an opening at a rear end toward an inner bottom at a front end. The opening of the thin-walled bag hole into the spacer-collar insertion hole is closed by a spacer collar that is formed and inserted into the spacer-collar insertion hole, and the metal material is sealed in the closed thin-walled bag hole. The second feature is that the sealing is performed.

[0010] In addition to the second feature, the present invention further comprises a spacer collar inserted into the spacer collar insertion hole, a tip of the spacer collar inserted into the thin bag hole, and a rear end of the spacer collar inserted into the spacer collar insertion hole. The metal material is hermetically sealed in a thin bag hole closed at a distal end of the spacer collar, which is disposed in contact with a set screw fixed to the opening, and the distal end of the spacer collar is thinned by an elastic member. A third feature is that the elastic member is elastically pressed and pressed inward.

[0011] In addition to the second and third features, the present invention further comprises a heat pipe disposed in at least the thin bag hole of the core, and the metal material sealed in the thin bag hole is formed by the heat pipe. The cooling is a fourth feature.

Further, in the present invention, in addition to the first feature, a fifth feature is that the metal material is made of lead or tin or an alloy of lead and tin.

[0013]

According to the first feature, a desired dimension can be obtained at the time of casting of a product, and at the time of taking out a product, the core can be contracted in a smaller direction than the contraction of a casting hole of the product. This makes it possible to achieve a straightened casting hole without giving the core a holding force to the core.

According to the second feature, the metal material can be easily sealed in the thin bag hole.

According to the third feature, even if the molten metal material leaks from the thin bag hole into the spacer collar insertion hole, the distal end of the spacer collar is pressed by the elastic member corresponding to the leak. As it enters the thin-walled bag hole,
There is no air in the thin bag hole, and the shape of the product equivalent portion of the core can be made uniform and stable.

According to the fourth feature, at the time of taking out the product, the core is accurately adjusted to a desired temperature by the heat pipe.
In addition, since the temperature can be reliably reduced, the core can be more easily taken out of the product.

According to the fifth feature, it is suitable as a metal material to be enclosed in a thin bag hole. That is, these metallic materials have melting, solidifying conditions, economy and market availability.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a casting core in a casting apparatus according to the present invention will be described below with reference to FIG. still,
Since the casting apparatus is the same as the conventional one, the description is omitted. Reference numeral 1 denotes a core for casting (hereinafter referred to as a core), which is made of an iron-based material (for example, SKD61). Core 1
Is formed at the tip end side thereof with a product equivalent portion 1A corresponding to the shape of the cast hole W1 of the product W.
A holder portion 1B is continuously provided from the rear end of A toward the rear end. Inside the core 1, from the rear end 1 C to the inner bottom 1 D at the front end
A spacer collar insertion hole 1E and a thin bag hole 1F are continuously provided. This thin-walled bag hole 1F must be formed at least in correspondence with the product equivalent part 1A.

A spacer collar 2 having a rod shape is inserted into the spacer collar insertion hole 1E with a very small gap, and the rear end 2A of the spacer collar 2 is formed on the rear end 1C side of the spacer collar insertion hole 1E. It comes into contact with the set screw 3 screwed into the female screw hole to prevent its movement in the longitudinal axis direction. According to the above, thin bag hole 1F
The opening to the spacer collar insertion hole 1E is closed by the distal end 2B of the spacer collar 2, and further closed by the outer periphery of the spacer collar 2 and the inner periphery of the spacer collar insertion hole 1E. Sealed.

Then, lead as the metal material 4 is hermetically sealed in the closed thin bag hole 1F. It is important that the lead be hermetically sealed without containing air in the closed thin bag hole 1F. When the lead sealed in the thin-walled bag hole 1F is melted, the lead is held so as not to leak from the thin-walled bag hole 1F into the spacer collar insertion hole 1E.

In the core 1 formed as described above, the holder 1B is attached to the core holder 15 as in the conventional case, and the female mold 11A of the fixed-side insert 11 and the female mold 13A of the movable-side insert 13 are provided. The product-equivalent portion 1A of the core 1 is inserted and arranged in the cavity formed by the above.

The casting of a product using an aluminum material using the core 1 will be described below. This casting is performed by the same process as the conventional one, and the mold closing step (a state in which the fixed master block 10 and the movable master block 12 are in contact with each other and the core 1 is inserted into the cavity as shown in FIG. 5).
-Injection process-Cooling process-Mold opening product removal process is performed.

More specifically, in the injection step, aluminum is heated to 625 ° C. and is in a molten state, and the molten metal is poured into a cavity through a gate hole (not shown) formed in a mold. . In this state, the product-equivalent portion 1A of the core 1, which is placed in the cavity, is heated to approximately 625 ° C. by receiving the temperature of the molten metal. According to the above, the lead in the thin bag hole 1F of the core 1 formed inside the core 1 facing the product equivalent part 1A is:
According to this, lead is heated to a temperature far exceeding its melting point of 328 ° C. and melts. And
In the above, according to the fact that the lead in the closed state is melted in the thin bag hole 1F, the lead expands greatly and increases its internal pressure.
As shown in FIG. 2, the outer diameter of the product equivalent portion 1A is B (m
m). On the other hand, since the cast-out hole W1 of the product W is formed following the product-equivalent portion 1A of the core 1, its inner diameter is formed as B (mm).

Next, the mold is subjected to a cooling and solidifying step while maintaining the mold closed state (the state shown in FIG. 5), and the temperature in the cavity gradually decreases with time. Then, in this example, the cooling step is finished at 325 ° C., and then the mold opening product removing step is performed.

In the mold opening product removal step, the movable matrix 12 is moved downward in FIG. 5, the movable matrix 12 is separated from the fixed matrix 10, and the product equivalent portion 1A of the core 1 is extracted from the cavity. This is the step of taking out the product W. For example, the mold opening product removal process is performed in a product removal range of 225 ° C. to 325 ° C. in FIG. It should be noted here that, for example, when the mold opening product removal step is performed at 275 ° C., the diameter C (mm) of the cast hole of the product W made of aluminum and the core 1
The relationship with the outer diameter D (mm) of the product equivalent part 1A is C> D
It is to become. This is because, in a state where the molten lead in the thin bag hole 1F of the core 1 has a temperature lower than its melting point of 328 ° C., the lead solidifies and the internal pressure in the thin bag hole 1F decreases,
This is due to a large shrinkage exceeding the shrinkage amount of the cast hole W1 of the product W made of aluminum.

According to the above description, the inner diameter C (mm) of the cast hole W of the product W and the outer diameter D (m
m), a gap of (C-D) mm is formed, and according to this, the cast-out hole W1 does not apply a holding force to the product equivalent portion 1A of the core 1. Therefore, when the product W is taken out, a straight hole having an inner diameter of C mm is formed in the cast hole W1 of the product W. At this time, (C) is formed between the cast hole W1 and the product equivalent portion 1A.
-D) Since a gap of mm is formed,
Can be easily pulled out. In the above, the diameter of the product equivalent part 1A is formed to be constant in the longitudinal direction.

In casting the aluminum product, lead was sealed in the thin bag hole 1F of the core 1, but when zinc was used as a product material, the melting point of zinc (387 ° C.)
Is lower than the melting point of aluminum (580 ° C.), the metal material to be sealed in the thin bag hole 1F is the melting point of lead (3
Tin having a melting point (232 ° C.) lower than 28 ° C.) is preferred. This is due to the lower product extraction temperature of zinc compared to aluminum. The product take-out temperature may vary depending on the casting conditions of the product and the shape of the product. However, it is preferable to use an alloy of lead and tin because the degree of adaptation to the product can be increased.

Next, another embodiment of the core according to the present invention will be described with reference to FIG. The outer shape of the core 1 is the same as the example of FIG. In this example, the thin bag hole 1F is formed to extend in the direction of the holder 1B (toward the rear end) beyond the product equivalent part 1A. In other words, the hole depth from the rear end 1C of the spacer collar insertion hole 1E is formed shallower correspondingly. On the other hand, the spacer collar 2 is formed at its leading end with a leading end 2E of a spacer collar inserted into the thin-walled bag hole 1F with a small gap, and at the trailing end, the rear end of the spacer collar having a smaller diameter than the spacer collar inserting hole 1E. 2F is formed. The set screw 3 is screwed to the rear end side of the spacer collar insertion hole 1E as in FIG.

Then, the spacer collar 2 is inserted from the opening of the rear end 1C of the spacer collar insertion hole 1E, and then the rear end of the spacer collar insertion hole 1E is set with a set screw 3
Close with. At this time, the rear end 2 of the spacer collar 2
The end 2A of F comes into contact with the tip of the set screw 3, while the tip 2E of the spacer collar 2 is inserted into the thin bag hole 1F. Therefore, the spacer collar insertion hole 1 of the thin bag hole 1F
The opening on the E side is closed and sealed by the distal end 2E of the spacer collar, and the same metal material 4 as described above is sealed in the sealed thin bag hole 1F.

On the other hand, a step 2G is formed at a connection portion between the spacer collar 2 and the tip 2E of the spacer collar, and a longitudinal direction is provided between the step 2G and the bottom 1P of the spacer collar insertion hole 1E. A gap X is formed along the gap.

An elastic member 5 such as a coil spring is contracted around the outer periphery of the rear end 2F of the spacer collar 2. The distal end of this coil spring is
And the rear end 2F of the spacer collar is locked to the stepped portion 2H, and the rear end of the coil spring is locked to the front end of the set screw 3. Therefore, the spacer collar 2 is constantly pressed toward the tip end (in the direction of the thin bag hole 1F) by the elastic member 5.

According to the core of the second embodiment, the metal material 4 in the thin bag hole 1F leaks into the spacer collar insertion hole 1E from the minute gap between the outer periphery of the distal end 2E of the spacer collar and the thin bag hole 1F. In this case, the distal end 2E of the spacer collar 2 is moved toward the distal end in the thin-walled bag hole 1F according to the amount of leakage. Material 4
Can be charged by Therefore, a change in internal pressure due to expansion and contraction of the metal material 4 can be immediately transmitted to the thin-walled bag hole 1F, and the deformation of the thin-walled bag hole 1F can be accurately maintained.

In another embodiment of the core shown in FIG. 4, the heat pipe 6 is inserted and arranged in the thin bag hole 1F.
The metal material in the thin-walled bag hole 1F is cooled by evaporating the refrigerant at the front end of the heat pipe 6, and the refrigerant is liquefied again with cooling water at the rear end of the heat pipe 6. In the solidification step or the product removal step, the cooling water is applied to the heat pipe 6 so that the metal material in the thin-walled bag hole 1F can be forcibly cooled and the solidification control of the metal material 4 is actively performed. And a highly accurate straight hole can be formed by casting. In the figure, reference numeral 7 denotes a cooling system, which includes a cooling water introduction path 7A, a cooling water circulation path 7B, and a cooling water discharge path 7C, and is arranged such that the rear end of the heat pipe 6 faces the cooling water circulation path 7B. You. The supply and cutoff of the cooling water into the cooling water circulation path 7B is performed by, for example, arranging an opening / closing valve linked to the cooling / solidification step in the cooling water introduction path 7A, and opening the opening / closing valve in the cooling / solidification step to open the cooling system What is necessary is just to circulate the cooling water inside.

[0034]

As described above, according to the core for casting according to the present invention, a thin-walled bag hole is provided inside at least a product equivalent portion corresponding to a product portion of the core, and the thin-walled bag hole is provided in the thin-walled bag hole. The product is in a molten state in the range from the product take-out temperature to the product pouring temperature, and the metal material that solidifies in the product take-out temperature range is hermetically sealed, so when opening the mold containing the core to take out the product The casting hole of the product does not cling to the core, and the casting hole can be formed by casting as a straight hole. Was obtained.

Further, the opening of the thin-walled bag hole into the spacer collar insertion hole is closed by a spacer collar inserted and fixed in the spacer-collar insertion hole, and the metal material is sealed in the closed thin-walled bag hole. According to the encapsulation,
It is easy to form a closed thin-walled bag hole, and it is possible to easily perform an operation of enclosing a metal material in the thin-walled bag hole.

Further, the metallic material is hermetically sealed in the thin-walled bag hole closed at the distal end of the spacer collar, and the distal end of the spacer collar is elastically pressed toward the thin-walled bag hole by an elastic member. According to the force, even when a part of the metal material in the thin-walled bag hole is leaked, the metal material can always be filled in the thin-walled bag hole, and according to this, the expansion of the metal material due to a thermal change is performed. The shrinkage can be quickly and accurately transmitted to the thin-walled bag hole, and an accurate cast hole can be formed.

In addition, according to the fact that the metal material sealed in the thin-walled bag hole is cooled by the heat pipe, the cooling of the metal material does not depend on natural cooling, but can be reliably performed in the cooling and solidifying steps of the casting operation. The temperature can be lowered in a short period of time, which is effective for shortening the working time and forming a straight hole with high precision.

Further, according to the fact that the metal material sealed in the thin bag hole is made of lead or tin or an alloy of lead and tin,
Due to its thermal properties, it is particularly suitable when using aluminum or zinc as the material of the product.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a main part of an embodiment of a core for casting in a casting apparatus according to the present invention.

FIG. 2 is a diagram showing a change in diameter of a product and a core with respect to temperature.

FIG. 3 is a longitudinal sectional view of a main part showing a second embodiment of a core for casting according to the present invention.

FIG. 4 is a longitudinal sectional view of a main part showing a third embodiment of a core for casting according to the present invention.

FIG. 5 is a longitudinal sectional view of a mold drawing including a core in a conventional casting apparatus.

[Explanation of symbols]

 1 Core 1A Product equivalent part 1F Thin bag hole 2 Spacer collar 3 Set screw 4 Metallic material

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B22C 9/10 B22D 17/22

Claims (5)

(57) [Claims] 1. A core for casting used in a casting apparatus for molding a product, wherein the core is formed of a metal material, and the core is formed at least inside a part corresponding to a product corresponding to a product part of the core. A thin-walled bag hole is provided, and a metal material that is in a molten state in a range from a product take-out temperature to a product pouring temperature and solidifies in a product take-out temperature range is hermetically sealed in the thin-walled bag hole. Core for casting in a casting apparatus. 2. A spacer collar insertion hole and a thin-walled bag hole are formed continuously from the opening at the rear end toward the inner bottom at the tip inside the core, and are inserted into the spacer collar insertion hole. 2. An opening of the thin-walled bag hole into the spacer-collar insertion hole with a spacer collar fixed and fixed, and the metal material is hermetically sealed in the closed thin-walled bag hole. A core for casting in the casting apparatus according to the above. 3. The spacer collar inserted into the spacer collar insertion hole has a distal end inserted and disposed in the thin bag hole, and a rear end thereof is disposed in contact with a set screw fixed to the opening of the spacer collar insertion hole. Then, the metal material is hermetically sealed in the thin bag hole closed at the distal end of the spacer collar, and the distal end of the spacer collar is elastically pressed and urged toward the thin bag hole by an elastic member. A core for casting in a casting apparatus according to claim 2, characterized in that: 4. A heat pipe is disposed in at least the thin bag hole of the core, and a metal material sealed in the thin bag hole is cooled by the heat pipe.
A core for casting in the casting apparatus according to the above. 5. The core according to claim 1, wherein said metal material is lead or tin or an alloy of lead and tin.