Electricity: motive power systems – Braking – Plural – diverse or diversely controlled braking means
Reexamination Certificate
1999-11-05
2001-12-25
Ip, Paul (Department: 2837)
Electricity: motive power systems
Braking
Plural, diverse or diversely controlled braking means
C318S372000, C318S373000, C318S376000, C425S135000, C425S145000
Reexamination Certificate
active
06333611
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a motor drive apparatus used in an injection molding machine and adapted to supply electrical energy to a motor included in an injection apparatus or the like.
2. Description of the Related Art
Generally, an injection apparatus and a mold clamping apparatus—which together constitute a motor-driven-type injection molding machine—each contain an AC servomotor; and in each case electrical energy is supplied from a motor drive apparatus to the corresponding AC servomotor in order to advance and retract a screw provided in the injection apparatus or a movable platen provided in the mold clamping apparatus (see, for example, Japanese Patent Application Laid-Open (kokai) No. 4(1992)-278321).
Incidentally, in an injection step of a molding cycle, an injection operation for advancing at high speed the screw accommodated within a barrel of the injection apparatus is performed, and in a mold clamping step of the molding cycle, a mold open/close operation for advancing and retracting at high speed the movable platen—which is provided in the mold clamping apparatus to support a movable mold—is performed. Similarly, another recurring operation is performed in order to move the screw in a measurement step, and yet another recurring operation is performed in order to move an ejector pin in an ejection step for ejecting a molded product.
As described above, the molding process of the injection molding machine involves an operation for moving a heavy member such as a screw or a movable platen at high speed during each molding cycle. Therefore, at the beginning of movement or during a period in which a motor is accelerated, drive current instantaneously flows through the motor in an amount several times that flowing during a constant speed period subsequent to the acceleration period, and at the end of movement or during a period in which the motor is decelerated, the motor instantaneously generates a considerable amount of regenerative current.
Therefore, in a conventional motor drive apparatus, the circuit must be designed such that, in consideration of excessive drive current (peak current) flowing during the acceleration period, a performance margin is provided, resulting in an increased size of the apparatus and increased cost. In addition, since the regenerative current generated during the deceleration period is consumed and dissipated in the form of heat by use of a regenerative resistor or the like, energy is consumed wastefully.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a motor drive apparatus for an injection molding machine which eliminates the necessity of designing a circuit in consideration of excessive drive current (peak current) flowing during a acceleration period of a motor, to thereby reduce the size of the apparatus and cost.
Another object of the present invention is to provide a motor drive apparatus for an injection molding machine which can avoid wasteful consumption of energy and decrease the capacity of an electric power supply facility within a plant.
To achieve the above objects, the present invention provides a motor drive apparatus provided in an injection molding machine and adapted to supply electrical energy to a motor, the motor drive apparatus comprising an electricity accumulation unit for accumulating electrical energy; and an electricity accumulation circuit for accumulating in the electricity accumulation unit electrical energy regenerated from the motor during a deceleration period of the motor and for supplying the electrical energy accumulated in the electricity accumulation unit to the motor during an acceleration period of the motor. By virtue of the above-described structure, when a heavy member such as a screw of an injection apparatus or a movable platen of a mold clamping apparatus is moved at high speed in each molding cycle, at the beginning of movement or during an acceleration period, the electricity accumulation circuit adds the electrical energy accumulated in the accumulation unit to the electrical energy that is supplied from a power source to the motor, and during a deceleration period, electrical energy regenerated from the motor is accumulated in the accumulation unit. Thus, the electrical energy supplied from the power source is effectively averaged, which eliminates the necessity of designing a circuit in consideration of excessive drive current (peak current) flowing during an acceleration period of the motor. In addition, since the regenerative current generated from the motor during a deceleration period of the motor is accumulated in the accumulation unit as regenerative electrical energy, wasteful consumption of energy can be avoided.
REFERENCES:
patent: 4426610 (1984-01-01), Kawada et al.
patent: 4506766 (1985-03-01), Watanabe
patent: 4554999 (1985-11-01), Kamaike
patent: 4733146 (1988-03-01), Hamby
patent: 4761600 (1988-08-01), D'Atre et al.
patent: 5034669 (1991-07-01), Sako et al.
patent: 5070290 (1991-12-01), Iwasa et al.
patent: 5089760 (1992-02-01), Joyner
patent: 5245294 (1993-09-01), Kumar
patent: 5376867 (1994-12-01), Capetti
patent: 5436540 (1995-07-01), Kumar
patent: 5444348 (1995-08-01), Garrec
patent: 5446365 (1995-08-01), Nomura et al.
patent: 5469031 (1995-11-01), Chorey
patent: 5619107 (1997-04-01), Shinohara et al.
patent: 5622737 (1997-04-01), Hehl
patent: 5764023 (1998-06-01), Wieloch
patent: 5814954 (1998-09-01), Suzuki et al.
patent: 5916501 (1999-06-01), Hehl
patent: 6058031 (2000-05-01), Lyons et al.
patent: A4-278321 (1992-10-01), None
patent: 288979 (1995-10-01), None
Koide Atsushi
Nishida Satoshi
Shibuya Hiroshi
Yamaura Hiroshi
Birch Stewart Kolasch & Birch, LLP.
Ip Paul
Nisso Electric Company
LandOfFree
Motor drive apparatus for an injection molding machine does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Motor drive apparatus for an injection molding machine, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Motor drive apparatus for an injection molding machine will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2577243