JPH03106548A - Die casting apparatus and product - Google Patents

Abstract

PURPOSE:To make columnar hole diameter uniform by loosely penetrating a pin for hole as cast in a first fixed die at molten metal injection mechanism side divided into both of the first and second fixed dies in a die casting machine into the second fixed die and extending this into cavity. CONSTITUTION:The fixed die at molten metal injection mechanism side, having the cavity at mating face 5 of a movable die 21, is divided into the first and second fixed dies 1, 2, and the pin 12 for hole as cast fixed to the first fixed die is loosely penetrated into the second fixed die 2 and extended into the cavity 24. At initial stage of retreating movement of the movable die 21 at the time of opening the dies, the second fixed die is shifted by the fixed distance while clamping this die with the movable die 21. By this method, without deforming the casting 50 at the time of pulling out the pin 12 for hole as cast inserted into the cavity 24 from the molten metal injection mechanism side, diameters of the columnar holes 54, 55 can be uniformized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a die-casting device, and more particularly to a die-casting device for obtaining products having cylindrical holes of uniform diameter.

(Prior Art) In order to support a capstan of a tape recorder or the like, a die-cast product 50 as shown in FIG. 5, for example, has conventionally been used. In this product 50, a bearing post 53 stands up from a base plate 52 having a mounting hole 5l, and the support post 53 has bearing holes 54 and 55 at both ends and a tape window 56 in the middle. The bearing holes 54 and 55 both have an inner diameter or a cylindrical hole with a uniform diameter,
It is also necessary that the centers of both sides coincide with high precision, otherwise the recording and playback characteristics of a tape recorder etc. will be impaired.

A product as shown in FIG. 5 is usually cast using a fixed die 6l and a movable die 62 as shown in FIGS. 6 and 7. The movable die 62 is fixed to a mold clamping mechanism 63, and includes a cavity 64, a slight core 65 for forming the tape window 56, and a punching pin 6 for forming the bearing hole 55.
6, and an extruded sleeve 6 fitted around the outer periphery of the cast pin 66.
7, and the end of the casting pin 66 is fixed to the mold clamping mechanism 63. The fixed die 6l is fixed to a fixed plate 68 of the molten metal injection mechanism, and includes a spool 70 having a runner 69, a punching pin 71 for shaping the mounting hole 5l, and a bearing hole 54.
It has a cast-out pin 72 for shaping.

During casting, the fixed die 6l and the movable die 62 are closed, molten metal is injected into the cavity 64 from the molten metal injection mechanism via the runner 69, and after the molten metal solidifies, as shown in FIG. Separate the movable die 62 from the fixed die 6l. Next, as shown in FIG. 7, when the slide core 65 is moved in the direction of the arrow and the extrusion sleeve 67 is moved in the direction of the arrow, the casting 73 is extruded from the cavity 64.
A casting 73 as shown in FIG. 8 can be obtained.

Here, since the cast pins 7l and 72 are tapered as shown, the tapered cast hole 74 is formed at the position of the bearing hole 54. Therefore, this cast hole 74 is machined to form a cylindrical bearing hole 54 as shown in FIG. (Problem to be Solved by the Invention) Since the molten metal contracts when it solidifies, the casting 73 has the cast pins 66, 71 . 72 is tightly tightened. In the case of a cast-out pin inserted into the cavity 64 from the side of the mold clamping mechanism 63, such as the cast-out pin 66, an extrusion sleeve 6 is placed around it.
7 is provided and moved as shown in FIG. 7 to press around the hole 55 to be formed, the casting 73 can be pulled out without deforming it. However, the cast pin 71. In the case of a casting pin inserted into the cavity 64 from the molten metal injection mechanism side as shown in 72,
Since it is difficult to provide a means, such as the extrusion sleeve 67, to prevent the casting 73 from being deformed when it is pulled out, it is necessary to make it tapered so that it can be easily pulled out. For this reason, the hole formed in the casting 73 necessarily has a tapered shape, so in the case of the bearing hole 54, which is essential to have a cylindrical shape, machining had to be performed after casting.

In this way, machining after casting not only affects production costs because it increases the number of steps, but also significantly affects the dimensional accuracy of the product depending on the type of machining. There was a problem that caused serious damage. (Means for Solving the Problems) In the die casting apparatus according to the present invention, the fixed die has a first fixed gou on the molten metal injection mechanism side and a second gou on the movable die side by a dividing plane parallel to the closing plane with the movable die. It is divided into a fixed die and a fixed die. The casting pin, which has a non-tapered portion located in the cavity, loosely passes through the second fixed die and is fixed to the first fixed die. When the movable die moves to open the die, the second fixed die is configured to perform the following movements. When the die is closed, the second fixed die is in close contact with both the first fixed die and the movable die. When the movable die starts to move to open the die, the second fixed die initially remains in close contact with the movable die and separates from the first fixed die.
Once the second fixed die is separated from the first fixed die by a certain distance, it remains in that position, and only the movable die continues to move away from the second fixed die, completing the die opening operation.

(Function) The casting pin extending from the first fixed die into the cavity through the second fixed die has a cylindrical shape with a uniform diameter rather than a tapered shape, and the casting is surrounded by a cylindrical shape with a uniform diameter. It is formed.

At the beginning of the movement of opening the die, the second fixed die is in a closed state with the movable die, and in this state, the casting pin fixed to the first fixed die is pulled out.

Once the casting pin is completely removed, the second fixed die remains in that position, and only the movable die continues to move.
and the casting is taken out from the cavity when it has moved sufficiently away from the second fixed die. Therefore, even if the casting pin inserted into the cavity from the side of the molten metal injection mechanism is not tapered, it is pulled out from the casting while being held in place by the second fixed die, so that the PJ structure is not deformed. Therefore, the casting pin can form a cylindrical hole with a uniform diameter in the casting, making it possible to eliminate the need for machining after casting.

(Example) In FIGS. 1 to 4, l and 2 are a first fixed die and a second fixed die that are divided by a dividing surface 3, and the first fixed die l is a fixed plate 4 of a molten metal injection mechanism. The front surface of the second fixed die 2 forms a closing surface 5 with the movable die 2l. Recesses 6, 6 are formed in the closing surface 5 of the second fixing die 2, and screws 7, 7 having their heads in these recesses pass loosely through the second fixing die 2 from the bottom of these recesses. , is screwed into the first fixed die l. First and second fixed die l, 2
The dividing surface 3 has circular holes 8, 8 and 9, 9 at opposing positions.
are recessed, and the springs IO and IO are accommodated in a compressed state across the circular holes 8, 8 and 9, 9. Therefore, when the second fixed die 2 is in a free state, as shown in FIGS. 3 and 4, the force of the springs 10 and 10 causes the second fixed die 2 to separate from the first fixed die 1, The heads of the screws 7, 7 abut against the bottoms of the recesses 6, 6.

Reference numeral 1l is a casting pin inserted into the second fixing die 2 from the closing surface 5, and the exposed portion thereof is formed into a tapered shape. 12 is a casting pin inserted into the first fixed die l from the dividing surface 3, and loosely penetrates the second fixed die 2, and as shown in FIG. In this state, the tip protrudes from the closing surface 5, and this protruding portion has a cylindrical shape with a uniform diameter. A spool 13 passes through the second fixed die 2 and is fixed thereto, and has a runner 14 formed therein, and loosely passes through the first fixed die 1.

The movable die 2l is attached to the mold clamping mechanism 22, and the second
It has a closing surface 23 that comes into close contact with the closing surface 5 of the fixed die 2.

A cavity 24 and a runner 25 connected to the cavity 24 are recessed in the closing surface 23. A slite core 26 that moves in a direction parallel to the closing surface 23 and a casting pin 27 are inserted into the cavity 24, and the other end of the casting pin 27 is fixed to the mold clamping mechanism 22, and the casting pin 27 is fixed to the mold clamping mechanism 22. An extruded sleeve 28 is fitted around 27.

- In the device described above, when the die is in the closed state,
As shown in FIG. 1, the second fixed die 2 is connected to the first fixed die l.
At the same time, the movable die 22 also comes into close contact with this.

At this time, the slite core 26 is pushed into the cavity 24, the casting pins l2 and 27←忰 contact the side surface of the slite core 26, the casting pin 11 contacts the bottom of the cavity 24, and the runner 25 contacts the runner l4. connected to. In this state, the molten metal passes from the molten metal injection mechanism to the cavity 24 through the runners l4 and 25.
injected into the body.

When the molten metal in the cavity 24 solidifies, the mold clamping mechanism 22 starts moving the movable cavity 21 backward. At the beginning of the backward movement, as shown in Figure 2, the spring lO, 10
The second fixed die 2 moves while being pressed by the movable die 2l, and the casting pin l2 is pulled out from the casting 50 by this movement of the second fixed die 2.

When the heads of the screws 7, 7 come into contact with the bottoms of the recesses 6, 6, the second
Fixed dies cannot be moved any further.

Since the movable die 2l continues to move backward, the movable die 2l separates from the second fixed die 2, as shown in FIG. 3, and the casting pin 11 is pulled out from the casting 50. When the movable die 21 is sufficiently retracted to open the die, the slite core 26 is pulled out from the casting 50 as shown in FIG. 3, and then the extrusion sleeve 28 pushes the casting 50 as shown in FIG. , and push it out of the cavity 24.

By this operation, the casting pin 27 is pulled out from the casting 50.

In addition to using the springs 10 and 10 in the above embodiment, as a means for moving the second fixed die 2 while keeping it closed to the movable die 2l at the beginning of the backward movement of the movable die 2l, air pressure or liquid pressure can be used. Many modes are possible, such as a method of moving using the movable die 21 and a method of engaging the locking mechanism provided on the movable die 21 with the second fixed die 2.

〔Effect of the invention〕

As is clear from the above embodiments, according to the present invention, even if the casting pin inserted into the cavity from the molten metal injection mechanism side is not tapered, it can be pulled out without deforming the casting. , it is possible to eliminate the need for post-casting machining, which was previously indispensable, and achieve both reductions in production costs and maintenance of dimensional accuracy.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a sectional view of the die when it is closed, FIG. 2 is a sectional view of the die at the beginning of the opening movement, and FIG. 4 is a cross-sectional view of the molded product extruded from the die, FIG. 5 is a cross-sectional view of the molded material in the same embodiment, and FIG. 6 is the conventional die in the open state. FIG. 7 is a cross-sectional view of the cast product extruded from the conventional die, and FIG.
The figure is a cross-sectional view of a casting made by the above-mentioned conventional die. l...First fixed die, 2...Second fixed die, 3
...Dividing surface, 4...Fixing plate of molten metal injection mechanism, 5
...Closing surface of the second fixed die, 7...Screw (second
Something that limits the movement of a fixed die to a certain distance〉, lO・
...Spring (something that moves the second fixed die), l2
...Casting pin, 2l...Movable die, 22...
... Mold clamping mechanism, 23... Closing surface of movable die, 24.
...Cavity, 50...Cast.

Claims (2)

[Claims] (1) It has a fixed die on the side of the molten metal injection mechanism and a movable die on the side of the mold clamping mechanism, which close with their closing surfaces, and a cavity is formed in the closing surface of the movable die, and the fixed die is used for injecting the molten metal. In a die casting device in which a runner is formed from the mechanism to the cavity, the fixed die is divided into a first fixed die on the molten metal injection mechanism side and a second fixed die on the movable die side by a dividing plane parallel to the closing surface. Divide into 1st
A casting pin fixed to the fixed die is loosely passed through the second fixed die and extended into the cavity, and the second fixed die is inserted into the movable die at the beginning of the backward movement of the movable die to open the die. A die-casting device characterized in that a die-casting device is provided with means for moving the movable die a certain distance together with the movable die while the die is closed. (2) having a surface formed by a cavity on the movable die side of the die-casting device and a surface formed by a fixed die that closes to the movable die, and inward from the surface formed by the fixed die; A die-cast product characterized by having cylindrical holes of uniform diameter with a cast surface.