Light metal injection molding machine

Patent metadata

Field	Value
Publication number	US-10702914-B2
Application number	US-201816111226-A
Country	US
Kind code	B2
Filing date	Aug 24, 2018
Priority date	Aug 25, 2017
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

A light metal injection molding machine includes an injection cylinder, a seal cylinder, a plunger, and a seal mechanism having a first annular body, a second annular body and a third annular body. The first annular body is arranged in an opening of the seal cylinder, and maintains a semisolid state of a molding material in a first gap between its inner periphery surface and the plunger. The second annular body is arranged in the opening between the injection cylinder and the first annular body, and includes an anterior internal groove formed over its whole inner periphery surface and a plurality of anterior transverse holes passing through the inner periphery surface. The third annular body is accommodated into the anterior internal groove transformably in a radial direction of the plunger, and tighten the plunger by pressurization from molding material flowing into the anterior transverse holes.

First claim

What is claimed is:

1. A light metal injection molding machine, comprising:
an injection cylinder, which has an injection chamber filled with a molding material made of a light metal;
a seal cylinder, which has an opening;
a plunger, which passes through the opening, reciprocates in the injection chamber and injects the molding material; and
a seal mechanism, which prevents leakage of the molding material between the opening and the plunger, wherein
the seal mechanism comprises:
a first annular body, which is arranged in the opening, forms a first gap between an inner periphery surface of the first annular body and an outer periphery surface of the plunger, and maintains a semisolid state of the molding material in the first gap;
a second annular body, which is sandwiched between the injection cylinder and the first annular body along a moving direction of the plunger to be arranged in the opening so that lateral surfaces of the first annular body and the second annular body contact with each other, and which comprises an anterior internal groove which is formed over a whole inner periphery surface of the second annular body, and a plurality of anterior transverse holes passing through the inner periphery surface of the second annular body in a direction perpendicular to the anterior internal groove; and
a third annular body, at least a part of which is accommodated into the anterior internal groove transformably in a radial direction of the plunger, and which is pressurized by the molding material flowing into the anterior transverse holes to reduce diameter equally on a whole of the third annular body and tighten the plunger.

2. The light metal injection molding machine according to claim 1 , wherein the seal mechanism further comprises a pressing body, which presses the first annular body to fix the first annular body, the second annular body, and the third annular body to the opening.

3. The light metal injection molding machine according to claim 2 , wherein the pressing body cools the first annular body to a prescribed range of temperature, and maintains a semisolid state of the molding material.

4. The light metal injection molding machine according to claim 3 , wherein the pressing body comprises a passage for flowing of a cooling medium.

5. The light metal injection molding machine according to claim 1 , wherein the plurality of anterior transverse holes are the same in shape.

6. The light metal injection molding machine according to claim 1 , wherein the plurality of anterior transverse holes are arranged equally on a circumference of the second annular body when observed from a lateral surface of the second annular body.

7. The light metal injection molding machine according to claim 1 , wherein the second annular body forms a second gap between an inner periphery surface of the second annular body and an outer periphery surface of the plunger, and the molding material flows into the anterior transverse holes through the second gap.

8. The light metal injection molding machine according to claim 7 , wherein a temperature of the molding material in the second gap is lower than a temperature of the molding material inside the injection chamber, and is higher than the temperature of the molding material in the first gap.

9. The light metal injection molding machine according to claim 1 , wherein the molding material permeates between the inner periphery surface of the third annular body and the outer periphery surface of a plunger, and forms a third gap between the inner periphery surface of the third annular body and the outer periphery surface of the plunger.

10. The light metal injection molding machine according to claim 1 , wherein a fourth gap is formed between the inner periphery surface of a part of the second annular body on which the anterior internal groove is arranged and the outer periphery surface of the third annular body.

11. The light metal injection molding machine according to claim 1 , wherein a temperature of the molding material flowing to the anterior transverse holes is lower than a temperature of the molding material in the gap between the injection cylinder and the plunger, and is higher than a temperature of the molding material in the first gap.

12. The light metal injection molding machine according to claim 1 , wherein the first annular body further comprises a posterior internal groove which is formed over a whole inner periphery surface of the first annular body,
the posterior internal groove forms a combined internal groove integrated with the anterior internal groove, and
the third annular body is accommodated into the combined internal groove.

13. The light metal injection molding machine according to claim 12 , wherein the first annular body comprises a plurality of posterior transverse holes passing through the inner periphery surface of the first annular body in a direction perpendicular to the posterior internal groove, and
the plurality of posterior transverse holes form a combined transverse hole integrated with each of the plurality of anterior transverse holes.

14. The light metal injection molding machine according to claim 12 , wherein a fourth gap is formed between the inner periphery surface of a part of the first annular body and the second annular body on which the combined internal groove is arranged and the outer periphery surface of the third annular body.

Assignees

• Sodick Co Ltd

Inventors

• Fujikawa Misao

Classifications

• B22D17/2092

  Safety devices (for plastics B29C45/84) · CPC title

• B22D17/2015 Primary

  Means for forcing the molten metal into the die (for plastics B29C45/46) · CPC title

• B22D17/2227

  Die seals (for plastics B29C45/2608) · CPC title

• B22D17/007 Primary

  Semi-solid pressure die casting · CPC title

• B22D17/203 Primary

  Injection pistons (B22D17/2053 takes precedence; for plastics B29C45/53) · CPC title