Press machine having planetary gear system for multi-speed drive functionality

A method of operating a linear-actuated press machine comprising a first motor, a second motor, a linear actuator having a rotatable screw arrangement, a planetary gear system, and a tool coupled to the linear actuator for forming a part, the planetary gear system being driven by the first motor and the second motor, the planetary gear system driving the linear actuator, the method comprising:

• advancing the tool toward the part by operation of the first motor in a low-force and high-speed condition;
• forming the part with the tool by operation of the second motor in a high-force and low-speed condition, the second motor is coupled to a ring gear of the planetary gear system to drive the ring gear;
• and
• after the part has been formed by the tool, retracting the tool from the part by use of at least one of the first motor and the second motor.

A press machine for forming a part, comprising:

• a linear actuator having a male-female screw arrangement and an actuator rod that is coupled to the male-female screw arrangement, the actuator rod undergoing linear movement in response to rotational movement of the male-female screw arrangement;
• a press ram that is coupled to the actuator rod of the linear actuator, the press ram for receiving a tool for forming the part, the press ram undergoing movement toward or away from the part in response to the corresponding linear movement of the actuator rod;
• a planetary gear system including a ring gear, a sun gear, and a plurality of planet gears between the sun gear and the ring gear, the plurality of planet gears being attached to a planet carrier, the planet carrier rotating an output shaft for the planetary gear system, the output shaft being coupled to the male-female screw arrangement of the linear actuator;
• a first motor coupled to the planetary gear system for producing a low-force and high-speed condition on the press ram, the first motor is coupled to the sun gear
• a second motor coupled to the planetary gear system for producing a high-force and low-speed condition on the press ram, the second motor is coupled to the ring gear, and
• a braking mechanism to slow or stop the rotation of the sun gear when the second motor is operational to produce the high-force condition on the linear actuator.