JP3164723B2 - Metal injection machine sealing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seal device for sealing the inside of a cylinder and the outside air of a metal injection machine for molding a metal, for example, which needs to avoid contact with air.

[0002]

2. Description of the Related Art Conventionally, there has been known an injection molding machine in which an ingot-shaped metal material is heated and pulverized by a pulverizer, and then supplied into a heated injection cylinder to form a semi-solid slurry by a kneading screw in the cylinder. Are known. In such a device, the kneading screw is freely rotatable and movable back and forth in the cylinder, and while rotating, the metal material is strongly agitated, and is further divided and finely divided to produce a semi-solidified slurry, which is stored in front of the cylinder. After a certain amount is accumulated, the kneading screw is strongly extruded and injection molded.

When it is desired to avoid contact with air, such as an aluminum alloy or a magnesium alloy, the metal material is generally supplied with an inert gas until it is supplied into an injection cylinder. They are handled in an atmosphere or vacuum. Further, since it is not preferable that the inside of the injection cylinder comes into contact with the outside air, the inside of the cylinder is usually shut off from the outside air by a seal or the like.

[0004]

However, since the kneading screw in the injection cylinder moves back and forth while rotating around the axis, the kneading screw is susceptible to vibration force in the radial direction, for example. If the gap is simply sealed with a normal rotary seal and a sliding seal, there is a problem that the seal member or the like is easily damaged or abrasion becomes severe and the sealing effect is easily impaired.

[0005]

In order to solve this problem, the present invention attaches a seal case which surrounds a part of an outer peripheral surface of a shaft of a kneading screw to form a space inside the cylinder end face. A seal holder that fits loosely on the shaft is disposed in the space, and a seal member provided on the inner diameter of the seal holder is brought into contact with the outer peripheral surface of the shaft. Then, a pair of seal members provided in front and rear of the seal holder in the axial direction are brought into contact with both inner wall surfaces of the seal case, and the seal holder is supported in a floating manner in the space by the pair of front and rear seal members. .

[0006]

By arranging the seal holder in a floating state in the space inside the seal case, excessive stress is not applied even if the shaft axis oscillates in the radial direction, and the durability is increased. Moreover, the inside of the cylinder and the outside air are securely sealed by the pair of seal members before and after the seal holder and the seal members on the inner surface of the seal holder.

[0007]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a sealing device according to an embodiment of the present invention. FIG. 1 is a sectional view of the present sealing device, and FIG. 2 is an overall view of an injection molding machine.

The seal device of the present invention is configured as a seal device of an injection machine for molding a metal material, such as an aluminum alloy or a magnesium alloy, for which it is desired to avoid contact with oxygen. To prevent deterioration of material quality.

That is, as shown in FIG. 2, the injection molding machine includes a mold 2 connected to the injection side of the injection machine 1 and a metal material supply chamber 3 connected to the upper part of the injection machine 1. The ingot-shaped metal material supplied to the chamber 3 is processed to form a semi-solid slurry, which is injected into the cavity 4 of the mold 2.

The injection machine 1 is provided with a holder 6 on a support 5.
And a kneading screw 8 provided in the injection cylinder 7, and a main sealing device 10 is provided at a rear end of the injection cylinder 7.

A spiral groove 8a connected to the screw head 8c is formed at the tip end of the kneading screw 8, and a shaft shaft 8b is formed at the rear end connected to the screw groove 8a. A forward / backward drive cylinder unit and a rotation drive motor (not shown) are connected to the rear extension 8b. A check ring 9 is provided between the screw head 8c and the spiral groove 8a.

Then, the kneading screw 8 is rotated around the axis by the rotation driving motor, and the kneading screw 8 is moved forward or backward by the advance / retreat driving cylinder unit.

The material supply chamber 3 communicates with the inside of the injection cylinder 7 near the rear end of the spiral groove 8a of the kneading screw 8.

A biaxial chopper 11 for finely cutting and pulverizing a metal material is provided in the material supply chamber 3 and directly above a portion communicating with the injection cylinder 7, and further above the metal chopper (not shown). A material input chamber is provided.

The material supply chamber 3 is provided with a heating and heat retaining mechanism for heating the supplied material and keeping it warm.
An inert atmosphere generating mechanism or a vacuum mechanism for cutting off contact with oxygen is provided, and the air in the material supply chamber 3 is purged with an inert gas such as argon gas or nitrogen by the inert atmosphere generating mechanism or the vacuum mechanism. Substitution or vacuum is applied.

Incidentally, the injection cylinder 7 is also provided with a heating and heat retaining mechanism to promote the slurrying of the metal material.

In this type of injection molding machine, when an ingot-shaped metal material is put into the material supply chamber 3 in an inert atmosphere, the material is heated by a heating mechanism until it reaches, for example, a semi-solidified region. When the heating is completed, the ingot is finely cut by the operation of the chopper 11 and supplied into the injection cylinder 7.

In the injection cylinder 7, the supplied material becomes a semi-solidified slurry by the strong stirring action and heating of the spiral groove 8a, and is sequentially conveyed forward. The outflow of the slurry conveyed forward is restricted by a stopper at the tip of the injection cylinder 7 (not shown), so that the slurry is stored in the front of the injection cylinder 7, and the kneading screw 8 gradually moves backward instead. . When the slurry reaches a predetermined amount, after the stopper at the tip of the injection cylinder 7 is released, the kneading screw 8 is rapidly advanced and injected into the cavity 4 of the mold 2.

The sealing device 10 is provided for the purpose of shutting off the metal material supplied from the material supply chamber 3 into the injection cylinder 7 from the outside air at the rear end of the injection cylinder 7 in the above-described injection process. And as shown in FIG.
A gap formed between the injection cylinder 7 and the shaft shaft 8b is sealed. This gap allows thermal expansion.

For this reason, the seal device 10 comprises a seal case 12 attached to the end of the injection cylinder 7,
A seal holder 14 disposed in a space 13 in the seal case 12, a rotating / sliding seal 15 disposed between the seal holder 14 and the shaft shaft portion 8b, and a seal holder 14 and the seal case 12. A pair of O-rings 16 and 17 are provided between the wall surfaces.

That is, the seal case 12 is
Body part 12 fastened to the end face of injection cylinder 7 by
a, and a cover part 12b fastened to the end face of the main body part 12a by bolts 20. An O-ring 21 is disposed between the end face of the injection cylinder 7 and the main body part 12a.

The seal holder 14 is integrally formed by connecting a ring-shaped first member 22 and a second member 23 with bolts 24, and has a central portion between the first member 22 and the second member 23. A play insertion hole having a diameter larger than the outer diameter of the shaft shaft portion 8b is provided.

At substantially the center of the inner diameter of the seal holder 14, the ring-shaped rotating / sliding seal 15 which is in contact with the outer periphery of the shaft 8b is provided. The large diameter portion 15a
The second member 2 is sandwiched between the first member 22 and the second member 23.
3 and the rotation / slide seal 15 is made of, for example, Teflon having heat resistance. The rotating / sliding seal 15 also serves as a seal at the joint between the first member 22 and the second member 23.

A pair of dust seals 2 made of, for example, Teflon are provided before and after the rotation / slide seal 15.
5 and 26 are provided to prevent dust from adhering to the rotating / sliding seal 15. That is, the dust seal 25 on one side is formed by the groove
a and the dust seal 26 on the other side is the second member 2
3 are arranged in the groove 23b of the inner diameter portion, and are respectively in contact with the outer peripheral portion of the shaft shaft portion 8b.

On the other hand, a ring-shaped groove 22b is formed on the front surface of the first member 22, and the metal O-ring 16 is disposed in the groove 22b. A groove 23c is formed, and a metal O-ring 17 is provided in the groove 23c.

The O-rings 16 and 17 are in contact with the inner wall surface of the main body 12a of the seal case 12 and the inner wall surface of the cover 12b, respectively.

With the above configuration, the seal holder 14 is supported in a floating manner in the space portion 13, and the seal holder 14 follows even if the shaft shaft portion 8b swings in the radial direction. In this case, the inner O-ring 16 mainly exerts a sealing effect, and the outer O-ring 17 mainly assists the smooth swing.

The gap between the seal holder 14 and the shaft 8b is sealed by a rotary slide seal 15, and the gap between the seal holder 14 and the seal case 12 is particularly the inside of a pair of O-rings 16 and 17. O-ring 1
By sealing with 6, the inside of the injection cylinder 7 can be reliably shut off from the outside air. Then, even if the kneading screw 8 swings in the radial direction, the sealing effect is not impaired by the seal holder 14 following.

Moreover, no excessive stress is applied to the rotating / sliding seal 15 and the O-rings 16 and 17, and the durability of these members and the like is improved.

[0030]

As described above, in the sealing device of the injection machine of the present invention, the seal holder which is loosely fitted to the shaft is supported in a floating manner in the space inside the seal case, and is provided on the inner diameter of the seal holder. The seal member is brought into contact with the outer peripheral portion of the shaft, and a pair of seal members provided before and after the seal holder are brought into contact with both inner wall surfaces of the seal case, so that the inert gas flows out of the injection cylinder. Can be prevented, and outside air can be prevented from flowing into the injection cylinder. Further, even if the kneading shaft oscillates in the radial direction, the sealing effect is not reduced, and the durability of the sealing member and the like is improved. Further, since the clearance between the injection cylinder and the shaft during thermal expansion can be increased, the rotation and sliding of the kneading shaft become smoother, and the working efficiency is improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of the present sealing device.

FIG. 2 is an overall view of an injection molding machine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection machine 3 Material supply chamber 8 Kneading screw 8b Shaft shaft part 10 Seal device 12 Seal case 13 Space part 14 Seal holder 15 Rotation / slide seal 16, 17 O-ring

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22D 17/00 B22D 17/20 B22D 17/30

Claims (1)

(57) [Claims] A portion between a cylinder communicating with a metal material supply chamber in an inert atmosphere or a vacuum state and a shaft of a kneading screw which is rotatable and movable back and forth within the cylinder and which communicates with the outside air. In a sealing device of a metal injection machine adapted to seal a shaft case, a seal case which surrounds a part of the outer peripheral surface of the shaft and forms a space therein is attached to the end surface of the cylinder, and the shaft A seal holder that is loosely fitted in the seal holder is provided, and a seal member provided on the inner diameter portion of the seal holder is brought into contact with the outer peripheral surface of the shaft. The seal holder is brought into contact with each inner wall surface of the seal case, and the seal holder is floatingly supported in the space by the pair of front and rear seal members. Metal injection machine sealing device.