Slide driving device for presses
AssigneeAida Engineering, Ltd.
InventorYasuyuki Kohno
Life of this patent
Estimating the term…
Abstract
A slide driving device employs a variable-displacement pump/motor for driving a rotating element of the slide driving device. The displacement volume of the variable-displacement pump/motor, whose output drives the slide, is varied in response to deviation of measured driver parameters from commanded driver parameters. An energy storage device temporarily absorbs excess energy during a portion of a molding cycle, and returns the energy to the system for re-use. In one embodiment, the energy storage device is an accumulator. In a second embodiment, the energy storage device is a flywheel. The combination of variable displacement volume and energy storage maintains the fluid pressure substantially constant during a cycle of the slide driving device.
Claims20
A slide driving device for a press comprising:
- means for generating pressure in a hydraulic fluid;
- said means for generating pressure includes an accumulator;
- means for controlling said pressure to maintain said pressure within said accumulator within a prescribed range;
- said pressure being substantially constant during changes in a load on said press;
- rotating means, responsive to said pressure, for converting energy from said hydraulic fluid into rotational power;
- said rotating means including means for absorbing rotational drive force from said slide through said means for applying rotational power, and for converting said rotational drive force into stored energy for said hydraulic fluid, said stored energy being stored temporarily in said accumulator;
- said rotating means includes at least one variable displacement pump/motors and at least one fixed volume pump/motors;
- means for applying said rotational power to a slide driving mechanism of said press;
- means for varying a displacement volume of said rotating means;
- and
- means for controlling said displacement volume, thereby controlling a drive torque applied to said slide driving mechanism.
A slide driving device for a press comprising:
- means for generating pressure in a hydraulic fluid;
- said pressure being substantially constant during changes in a load on said press;
- said means for generating pressure includes an electric motor, a flywheel driven by said electric motor, and a variable displacement pump/motor receiving rotational drive force from said flywheel;
- said means for controlling including means for controlling a swash-plate tilt of said variable displacement pump/motor in a manner effective to maintain a fluid pressure of said hydraulic fluid discharged from said variable displacement pump/motor substantially constant;
- rotating means, responsive to said pressure, for converting energy from said hydraulic fluid into rotational power;
- said rotating means is effective to receive rotational drive force transferred from said slide via said means for applying and to convert said rotational drive force into stored energy for said hydraulic fluid;
- said rotating means includes at least one variable displacement pump/motors and at least one fixed volume pump/motors;
- means for transferring said stored energy from said flywheel to produce motor action of said variable displacement pump/motor of said fluid pressure generating means;
- means for applying said rotational power to a slide driving mechanism of said press;
- means for varying a displacement volume of said rotating means;
- means for controlling said displacement volume, thereby controlling a drive torque applied to said slide driving mechanism.
A slide driving device for driving a slide of a press, comprising:
- a variable displacement pump/motor;
- said variable displacement pump/motor producing a pressurized fluid;
- rotating means for driving said slide in response to said pressurized fluid;
- means for controlling a displacement volume of said variable displacement pump/motor in response to a deviation of a measured parameter of said slide driving device from at least one target parameter, whereby actuation of said slide is forced to conform generally to said at least one target parameter;
- said means for controlling includes proportional compensation during a first portion of a slide cycle, and a sum of proportional compensation and an integral compensation during a second portion of a slide cycle;
- and
- means for storing, temporarily, excess energy during a portion of a molding cycle.
Dependencies are inferred from the claim text.