JPH0133262Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a die-casting mold for casting a female thread or the like.

Conventionally, methods for manufacturing internal threads include a mechanical cutting method using thread processing and a manufacturing method using die-casting. The former mechanical cutting method has the drawbacks of high processing costs and difficulty in mass production. According to the latter manufacturing method using die-casting, inexpensive and mass production is possible, so this product is cheaper than a mechanically cut product. However, when manufacturing a tightening nut by die-casting, for example, when the material is zinc, its melting temperature is high (approximately 350°C to 380°C), and due to the effects of thermal expansion, (1) dimensional accuracy of the product may be affected. is difficult to come out.

(2) The sliding part of the mold is prone to galling and wear.

(3) Bonding between the product and the mold is likely to occur.

There are other problems. It is also known in die-casting technology that there is a requirement that mass production cannot be achieved unless the mold structure is simplified as much as possible. However, if the nut is to be manufactured by die-casting, the core mold to be inserted into the thread must be extracted by screw-out. For this purpose, a motor or the like is attached to one end of the core mold as ancillary equipment, and when the nut to be processed is cast and cooled, the core mold and ancillary equipment are attached to the central axis of the nut. When the core mold is rotated by the rotation of a motor etc., a part of the nut is protected by some means to prevent it from rotating all the way. This requires consideration, such as keeping it under control. Therefore, this method results in a complicated mold structure, and the accompanying equipment must be expensive due to the mold structure. Moreover, as the cast product cools, it contracts, so in order to easily remove the core mold, (A) create a draft angle between the inlet part of the thread groove and the outlet part on the opposite side. (B) The material of the core mold must be selected to prevent rotational wear. However, (A) above
If we adopt the countermeasure mentioned above, the dimensional accuracy of the thread groove diameter will decrease due to the draft angle, and the greater the number of screw threads, the greater the draft angle, which will further reduce the dimensional accuracy. I will do it. Furthermore, if a draft angle is provided, it becomes increasingly difficult to obtain dimensional accuracy of the inner diameter, outer diameter, and effective diameter of the screw, and the crest of the screw does not have a predetermined shape between the end and the inner portion, which is inconvenient. If the measure in item (B) is adopted, the manufacturing cost of the core mold itself will increase, which is also inconvenient.

As described above, although it is technically possible to obtain nuts by conventional die-casting, it requires a lot of expense in terms of manufacturing equipment and is difficult in terms of mass production. It was.

In view of the above-mentioned drawbacks of the conventional technology, the present invention enables casting products such as internal threads to be cast using a simple die-casting mold, and removes the casting products from the mold by moving the slide core. To obtain a die-casting mold for casting a female screw or the like which can be automatically removed and which can extremely easily produce a cast molded product with high commercial value without any ejector pin marks on the cast molded product.

Hereinafter, the present invention will be explained in detail with reference to an embodiment shown in the drawings.

In one embodiment of FIGS. 1 to 5, 1 is a fixed mold, and a cavity forming member 3 in which a cavity 2 for forming a product such as a female thread is formed is fixed in a recess 4. A runner member 7 is attached in which a runner 6 is formed and communicates with a nozzle 5 of a pouring device (not shown). Reference numeral 8 denotes a movable mold that is moved by an actuating device 9 such as a hydraulic device that is clamped to the fixed mold 1. The movable mold 8 has a small diameter tip that enters the cavity 2 of the fixed mold 1. A taper pin 10 is fixed thereto, and inclined pins 11, 11, 11, 11 having the same inclination as the inclination angle of the taper pin 10 are fixed on both sides of this taper pin 10. 1
Reference numerals 2 and 12 indicate the inclined pins 11 and 11 and slide cores that are slidably attached to the inclined pins 11 and 11, and these slide cores 12 and 12 have threaded portions such as internal threads inserted into the cavity 2. Thread forming portions 12a, 12a are formed. Reference numeral 13 denotes extrusion pins inserted into a plurality of extrusion pin insertion holes 14 formed in the movable mold 8, and these extrusion pins 13 are extrusion pins that are moved by an extrusion pin actuating device 15 such as a hydraulic device. It is fixed to the plate 16.

Incidentally, slopes 17, 17 having the same slope as the taper pin 10 are formed at both ends of the fixed mold 1, and the slide core 1 comes into contact with the slopes 17, 17.
The same inclined surfaces 18, 18 are also formed on 2, 12.

In the above structure, the actuating device 9 is operated to move the movable mold 8 toward the fixed mold 1 and clamp the mold as shown in FIG. Next, the pouring device (not shown)
is operated to force the molten metal into the cavity 2 from the runner 6. After the press-fitted molten metal solidifies within the cavity 2, the actuating device 9 is activated to remove the movable mold 8 from the fixed mold 1. At this time, slide core 1
2 and 12 also move in the same direction as the movable mold 8,
Since the solidified product A is stuck to the threaded portions 12a, 12a of the slide cores 12, 12, it exits from the cavity 2. Next, when the push-out pin actuating device 15 is activated to move the push-out plate 16 in the direction of the movable mold 8, the push-out pin 13 pushes the movable mold 8 in a direction that separates the slide cores 12, 12. That is, the slide core 1 is moved from the movable mold 8.
2 and 12 are extruded. At this time, the slide cores 12, 12 are projected while moving inward along the inclined pins 11, 11. Therefore, the product A and the threaded portions 12a, 12a of the slide cores 12, 12 come off, and the product A can be removed from the mold.

Next, when the actuating device 9 is actuated to move the movable mold 8 in the direction of the fixed mold 1, the slide cores 12,1
2 comes into contact with the fixed mold 1, moves along the inclined pins 11, 11, and comes into contact with the movable mold 8. At this time,
Thread forming portion 12a12 of slide cores 12, 12
a is located inside the cavity 2 and is in a mold-clamped state.

In the above embodiment, an example in which two slide cores are provided has been described, but the present invention is not limited to this, and the same implementation can be made even if there are two or more slide cores.

As is clear from the above description, the present invention provides the following effects.

(1) By extruding the slide core from the movable mold with an extrusion pin, the threaded portion of the slide core in which the threaded portion is formed can be moved inward. Therefore, the thread forming part can be easily removed from the product in which the internal thread is formed.

(2) Products with internal threads can be cast efficiently in a short time. Therefore, it is possible to reduce costs.

(3) Since the structure of the mold is simple, it is easy to manufacture the mold, it can be made in a short time, and the manufacturing cost can be reduced.

(4) Since the slide core can be moved by moving the movable mold and moving the ejecting pin,
There is no need for a dedicated sliding core moving mechanism as in the past, and costs can be reduced.

(5) By moving the slide core, the cast product can be automatically removed from the mold. It can prevent the marks from being left behind. Therefore, it is possible to mold a cast molded product with a clean molding surface and high commercial value.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention;
Figures 2 and 3 are explanatory diagrams of the fixed mold and movable mold,
FIGS. 4 and 5 are explanatory diagrams showing the operating state. DESCRIPTION OF SYMBOLS 1... Fixed mold, 2... Cavity, 3... Cavity molding member, 4... Recessed part, 5... Nozzle,
7... runner member, 6... runner, 8... movable mold,
9... Actuation device, 10... Taper pin, 11...
... Inclined pin, 12 ... Slide core, 12a ...
Thread forming part, 13... Push-out pin, 14... Push-out pin insertion hole, 15... Push-out pin actuating device, 16... Push-out plate, 17... Inclined surface, 18...
...Slope.

Claims (1)

[Scope of utility model registration request] a fixed mold, a cavity formed in the fixed mold, and a movable mold clamped to the fixed mold;
a taper pin with a small diameter tip whose tip enters into the cavity fixedly installed in the movable mold; and at least two inclined pins in the movable mold that face in the direction of the fixed mold and have the same inclination as the taper pin; It is characterized by comprising at least two or more slide cores each having a member that is movable along an inclined pin and that enters into the cavity to form a threaded portion such as a female thread, and an extrusion pin that moves the slide cores. A die-casting mold for casting internal threads, etc.