JPH02187243A - Die casting method for forming female screw - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a mechanism for molding an undercut female thread in die casting, and is capable of automatic forward/reverse movement and stopping. This invention relates to a method of die-casting a female thread shape using a motor and a gear that converts one revolution into reciprocating (stroke) motion.

[Conventional technology]

A conventional device, as described in Japanese Unexamined Patent Publication No. 61-259863, chucks a screw molded product and releases it from the mold while rotating the screw molded product and part of the chuck device without destroying the threads. It became.

Conventionally, the shape of the female thread is undercut 1-, so
Molding using a die cast 1- was not performed, and processing was performed using a tapping process using machining. As in the present invention, when die-casting an undercut female thread, the motor is not reciprocated or rotated, and after the female thread is cast, the core pin can be avoided without crushing the thread from inside the die-cast product. I can't find any method of die-casting.

[Problem to be solved by the invention]

Die casting is a method in which molten metal is press-fitted into a mold at high speed and high pressure, allowing repeated casting.
The shape determines the shape of the die-cast product. If the undercut shape in die casting etc. is perpendicular to the direction of sliding or movement of the mold, it is impossible to cast out the undercut. Since it had an undercut shape, molding by die-casting was not carried out, and the necessary threads were added by a tapping process in one machining process.

The purpose of the present invention is to eliminate and simplify the tap process of machining by die-casting a female thread shape, and from the die-casting part of the female thread forming part of the mold for the female thread shape part, without crushing the thread thread. The solution is to obtain a die-cast molding with an internal thread formed by die-casting.

[Means to solve the problem]

In order to avoid the mold from the undercut-shaped thread forming part without crushing the thread, the present invention can be rotated in the normal direction.
Using a motor (stepping motor in the present invention) that can reverse and stop, and gears, the other end of the mold for forming the female thread part (mainly the core pin) is shaped like a ball screw, and the rotation of the motor is controlled by the gears to achieve stroke motion and rotation. A thread for female thread forming is provided at one end, and after die-casting, the core pin for female thread is rotated and avoided from inside the die-cast product along the thread. Position of core pin for female thread,
Stroke etc. are controlled by commands from a digital controller to control the stepping motor, positioning, and feed speed.

[Effect]

The core pin for female thread forming receives signals from the machine body to the die casting 1, such as mold opening and completion of extrusion, to the digital controller, and the digital controller converts the rotation with a gear, and performs a stroke motion while rotating. After entering the cavity and performing die-casting, it moves to avoid rotation from inside the female thread molding.

In other words, the motor is rotated forward by the digital controller.
Reversing, stopping, and starting are controlled, and the rotation of the motor is controlled by gears on a core pin with a ball screw, and the stroke and
The rotational motion is converted into a die-cast product along the internal threads, and the product is die-cast without crushing the internal threads.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

A core pin 6 for forming a female thread (hereinafter simply referred to as a core pin) is attached to the outer wall of the movable mold 2 via a holder 12,
The core pin 6 converts the rotation of the motor 8 into a stroke motion and one rotation motion by the motor 8 attached to the outer wall 2 of the movable mold 2, and the rotation of the motor 8 into a stroke motion and a one-rotation motion.
The structure is designed to prevent intrusion into the interior.

An example of operation is shown below.

The digital controller 15 receives a signal indicating completion of extrusion return or completion of spraying from the die-casting machine, and the digital controller 15 issues a command to start the motor 8 for one rotation, and the rotation of the motor 8 is changed into a stroke motion via the gear 9. The core pin 6 enters the movable mold 2, and the sensor 11 detects that the sliding position of the core pin 6 is completed.
A signal is sent to the die-casting machine, the die-casting machine is clamped, the core pin 6 is fixed by the stopper 4, and the molten metal 14 supplied to the sleeve 6 is transferred to the plunger tip 1.
3 pressurizes and fills the cavity 3, and after holding it for a predetermined time, the mold is opened. In response to the mold opening completion signal, the motor 8 is operated via the digital controller 15, and the rotation of the motor 8 is controlled by the gear 9 to perform a stroke motion. , as well as along the internal thread which is converted into rotary motion and die-cast.
Inside the die-cast product, avoid the core pin 6 and insert the sensor 11.
The product 17 is ejected from the movable mold 2 by the extrusion signal to the die cutter 1, and is taken out by a conveying device or the like. In the figure, 1 is a fixed type, and 14 is a molten metal.

This allows the machining process to tap female threads.
It is molded during the die-casting process, allowing for the omission of processes and the creation of an i-butane product.

According to this embodiment, (1) Reduction and simplification of processes and man-hours.

(2) Because it is die-cast, there are no defects such as holes in the tapped portion.

(3) The female thread-like undercut shape is formed by die-casting so that the female thread forming part core pin avoids the rotation of the motor along the thread.

Application can be expanded to complex parts of other shapes.

〔Effect of the invention〕

According to the present invention, the female thread is formed during the die-casting process, and the tapping process of machining can be simplified.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of an embodiment of the present invention, and FIG. 2 is a sectional view of a die-cast product formed by the apparatus shown in FIG. 1... Fixed type, 2... Movable type, 3... Cavity, 4... Stopper, 5... Stopper adjustment screw, 6
...Female thread forming core bin, 7...Stopper groove, 8
... Staping motor, 9... Gear, 10...
Motor holding stand, 11... Position sensor 12... Holding stand, 13... Plunger chip, 14... Molten metal, 15... Digital controller, 16... Sleeve, 17... Die casting product .

Claims (1)

[Claims] 1. In die-casting in which molten metal is press-fitted into a mold, a mechanism is provided to avoid the threads of a core pin for forming a female thread from within the die-cast product without crushing it, and to automatically correct the thread. Turn,
A core is provided with a motor capable of reversing and stopping, and a gear that converts the rotation of the motor into reciprocating motion and rotary motion, and slides while rotating along the thread of the female thread, and returns from within the die-cast product. A female thread forming die-casting method featuring a pin mechanism.