Motor drive injection unit, die cast machine having the unit, and motor drive injection method
First Claim
1. A motor drive injection unit for injecting a molding material in a cylinder into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston in the cylinder, the motor drive injection unit including surge pressure control means for placing the injection piston in the cylinder in an unmovable state when at least a predetermined amount of a load is applied to the injection piston by the molding material in the cylinder.
1 Assignment
0 Petitions
Accused Products
Abstract
In a motor drive injection unit and a motor drive injection method, which can obtain an injection speed suitable for a molding material having fast solidifying speed as well as can securely carry out pressure keeping for a predetermined period of time while making a position of an injection piston unmovable after injection and filling are completed, a molding material in a cylinder is injected into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston in the cylinder through a plunger with a ball screw, a surge pressure control means is provided for placing the injection piston in the cylinder in an unmovable state when at least a predetermined amount of a load is applied to the injection piston by the molding material in the cylinder, the surge pressure control means includes a combination of rotation control means of the electric servo motor and an upward movement suppression mechanism of the injection piston, and further, an injection speed of the injection piston is increased by providing a time difference between initial motions of the plunger and the injection piston.
27 Citations
8 Claims
- 1. A motor drive injection unit for injecting a molding material in a cylinder into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston in the cylinder, the motor drive injection unit including surge pressure control means for placing the injection piston in the cylinder in an unmovable state when at least a predetermined amount of a load is applied to the injection piston by the molding material in the cylinder.
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7. A motor drive injection method of injecting a molding material in a cylinder into a metal mold by converting a rotational motion of an electric servo motor into a reciprocating motion of an injection piston coupled with a plunger to which a ball screw threaded into a ball nut portion is formed, the motor drive injection method including the steps of:
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increasing a rotation speed of the electric servo motor up to an injection speed of the injection piston; and
injecting a molding material in a cylinder into a metal mold in a short time by increasing an initial speed of the injection piston by providing a predetermined time difference between a motion of the plunger in an injecting direction and an injecting motion of the injection piston. - View Dependent Claims (8)
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Specification