JPH0375258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of 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.

[Conventional technology]

Conventionally, a die-cast product 50 as shown in FIG. 5, for example, has been used to support a capstan of a tape recorder or the like. In this product 50, a bearing post 53 stands up from a base plate 52 having a mounting hole 51, and the bearing post 53 has bearing holes 54, 55 at both ends and a tape window 56 in the middle. Bearing holes 54, 5
5 must all have a cylindrical hole with a uniform inner diameter, and the centers of both must match with high precision, otherwise recording with a tape recorder, etc.
Regeneration properties are impaired. Products like the one shown in Figure 5 are
Typically, a fixed die 6 as shown in FIGS. 6 and 7
1 and a movable die 62. The movable die 62 is fixed to a mold clamping mechanism 63, and includes a cavity 64, a slide core 65 for forming the tape window 56, a casting pin 66 for forming the bearing hole 55, and a casting pin 66 for forming the bearing hole 55. It has an extrusion sleeve 67 fitted around the outer periphery, and the end of the casting pin 66 is fixed to the mold clamping mechanism 63. The fixed die 61 is fixed to a fixed plate 68 of the molten metal injection mechanism, and includes a spool 70 having a runner 69, a casting pin 71 for forming the mounting hole 51, and a casting pin 71 for forming the bearing hole 54. It has a pin 72.

During casting, a fixed die 61 and a movable die 62 are used.
The molten metal is injected into the cavity 64 from the molten metal injection mechanism via the runner 69, and after waiting for the molten metal to solidify, the movable die 62 is separated from the fixed die 61 as shown in FIG. 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 and becomes as shown in FIG. A casting 73 can be obtained.

Here, since the cast pins 71 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 7
3, the cast pins 66, 71, and 72 are strongly tightened. In the case of a cast-out pin inserted into the cavity 64 from the mold clamping mechanism 63 side, such as the cast-out pin 66,
An extrusion sleeve 67 is provided around it, and by moving this as shown in FIG. 7 and pressing the area around the hole 55 to be formed, the casting 73 can be pulled out without deforming it. .

However, in the case of casting pins inserted into the cavity 64 from the side of the molten metal injection mechanism, such as the casting pins 71 and 72, a means such as an extrusion sleeve 67 to prevent the casting 73 from deforming during extraction must be provided. Since it is difficult to remove, it is necessary to make it tapered so that it can be easily pulled out. Therefore, the hole formed in the casting 73 necessarily has a tapered shape, so in the case of the bearing hole 54, which must be cylindrical, machining had to be performed after casting.

In this way, performing machining after casting
This itself increases the number of steps, which not only affects production costs, but also poses the problem that, depending on the type of machining, the dimensional accuracy of the product may be significantly impaired.

[Means to solve the problem]

In the die casting device according to the present invention, 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 with the movable die. There is. The casting pin, which has a non-tapered portion located within the cavity, loosely passes through the second fixed die and is fixed to the first fixed die. When the movable die moves and the die opens, the second fixed die is configured to perform the following movement.

When the dies are closed, the second fixed die is in close contact with both the first fixed die and the movable die. When the movable die starts moving to open the die, the second fixed die leaves the first fixed die while remaining in close contact with the movable die at the beginning. 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.

[Effect]

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 formed surrounding this.

At the beginning of the die opening movement, 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.

When the casting pin is completely removed from the second fixed die,
It remains in that position and only the movable die continues to move,
The casting is removed from the cavity when the movable die is sufficiently far away from the first and second fixed dies.

Therefore, even if the casting pin inserted into the cavity from the molten metal injection mechanism side is not tapered, the casting is pulled out while being held by the second fixed die, so that the casting is not deformed. Therefore, a cylindrical hole with a uniform diameter can be formed in the casting by using this punching pin, and machining after casting can be made unnecessary.

〔Example〕

In FIGS. 1 to 4, 1 and 2 are a first fixed die and a second fixed die that are separated by a dividing surface 3, and the first fixed die 1 is a fixed plate 4 of a molten metal injection mechanism.
The front surface of the second fixed die 2 is connected to the movable die 2.
It forms a closing surface 5 with 1. 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 loosely pass through the second fixing die 2 from the bottom of these recesses. , screwed into the first fixed die 1. The dividing surfaces 3 of the first and second fixed dies 1 and 2 have circular holes 8 at opposing positions.
8 and 9, 9 are recessed, and springs 10, 10 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, the force of the springs 10 and 10 moves the second fixed die 2 away from the first fixed die 1, as shown in FIGS. 3 and 4. When separated, the heads of the screws 7, 7 abut against the bottoms of the recesses 6, 6.

Reference numeral 11 denotes a casting pin inserted into the second fixing die 2 from the closing surface 5, and the exposed portion thereof is tapered. Reference numeral 12 denotes a casting pin that is inserted into the first fixed die 1 from the dividing surface 3 and loosely passes through the second fixed die 2, so that the first and second fixed dies 1 and 2 are closed as shown in FIG. When in the state, the tip is on the closing surface 5
This protruding portion has a cylindrical shape with a uniform diameter. 13 is a spool that passes through the second fixed die 2 and is fixed thereto, and has a runner 14 inside.
is formed and loosely passes through the first fixed die 1.

The movable die 21 is attached to a mold clamping mechanism 22 and has a closing surface 23 that closely contacts the closing surface 5 of the second fixed die 2 . A cavity 24 is provided on the closing surface 23.
A runner 25 connected thereto is recessed. A slide core 26 that can move 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 to prevent casting. An extruded sleeve 28 is fitted around the pin 27.

In the above-described apparatus, when the die is in the closed state, as shown in FIG. 1, the second fixed die 2 is in close contact with the first fixed die 1, and at the same time, the movable die 21 is in close contact with this. At this time, the slide core 26
is pushed into the cavity 24, the casting pins 12 and 27 contact the side surfaces of the slide core 26, the casting pin 11 contacts the bottom of the cavity 24, and the runner 2
5 is connected to the runner 14. In this state, molten metal is injected from the molten metal injection mechanism into the cavity 24 through the runners 14 and 25.

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 FIG. , the casting pin 12 is pulled out from the casting 50.

When the heads of the screws 7, 7 abut against the bottoms of the recesses 6, 6, the second fixed die cannot be moved any further.
Since the movable die 21 continues to move backward, the movable die 21 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 slide core 26 is pulled out from the casting 50 as shown in FIG.
As shown, the extrusion sleeve 28 pushes the casting 50 and forces it out of the cavity 24. By this operation, the casting pin 27 is pulled out from the casting 50.

Note that at the beginning of the backward movement of the movable die 21, the second
As a means for moving the fixed die 2 while being closed to the movable die 21, the spring 1 in the above embodiment is used.
In addition to the use of 0 and 10, the movable die 21 can be moved using air pressure or liquid pressure, and the locking mechanism provided on the movable die 21 can be used as a second
Many ways of engaging the fixed die 2 are possible.

〔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. This eliminates the need for post-casting machining, which was conventionally indispensable, making it possible to both reduce production costs and maintain dimensional accuracy.

[Brief explanation of drawings]

1 to 4 show one embodiment of the present invention, in which FIG. 1 is a cross-sectional view of the die when it is closed, FIG. 2 is a cross-sectional view of the die at the beginning of its 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 a casting extruded from the conventional die, and FIG. 8 is a cross-sectional view of a casting formed by the conventional die. 1...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 (for restricting the movement of the second fixed die to a certain distance), 10
...Spring (something that moves the second fixed die), 1
2... Second casting pin, 14... Runway, 21...
Movable die, 22... Mold clamping mechanism, 23... Closing surface of movable die, 24... Cavity, 26... Slide core, 27... First cast pin, 28... Extrusion sleeve, 50... Casting Items 54... Bearing hole (second cylindrical hole), 55... Bearing hole (first cylindrical hole), 56... Tape window.

Claims (1)

[Claims] 1. A fixed die on the side of the molten metal injection mechanism and a movable die on the side of the mold clamping mechanism whose closing surfaces are closed to each other, and a cavity is formed on the closing surface of the movable die, and a cavity is formed on the closing surface of the movable die, and a cavity is formed on the closing surface of the movable die. is a die casting device in which a runner is formed extending from the molten metal injection mechanism to the cavity, and the movable die includes a slide core that is movable parallel to the closing surface and whose tip reaches into the cavity; A first casting pin having a cylindrical shape with a uniform diameter and passing through the movable die from the mold clamping mechanism side into the cavity and having its tip abutted against the slide core, and a first casting pin surrounding the first casting pin and having a tip end that passes through the movable die and enters the cavity. and an extrusion sleeve terminating at the end of the cavity, and the fixed die is separated by a dividing surface parallel to the closing surface into a first fixed die on the side of the molten metal injection mechanism and a second fixed die on the side of the movable die. It has a cylindrical shape with a uniform diameter, is fixed to the first fixed die on the same central axis as the first casting pin, loosely passes through the second fixed die, and has a tip inside the cavity. At the beginning of the backward movement of the second casting pin in contact with the slide core and the movable die to open the die, the second fixed die is moved a certain distance together with the movable die while being closed to the movable die. A die-casting device comprising: means. 2 It has a columnar part, and this columnar part has a window that is largely cut out on the side by a cast surface, and first and second holes that are respectively bored from both ends to the window.
A die-casting product having a cylindrical hole, wherein the first and second cylindrical holes are located on the same central axis, and each hole has a surface formed by casting and has a uniform diameter. .