TECHNICAL FIELD

The present disclosure relates to a double-motor double-station screw press. During a normal operation of the screw press, left side and right side mechanisms can work symmetrically, and when the left side and right side mechanisms are no-load, only one motor works, and when any one of the mechanisms is loaded, the double motors work simultaneously.

BACKGROUND

Forming processing is widely used due to its advantages of high production efficiency, material saving, and high processing quality. Mechanical presses have advantages of stable transmission and high control accuracy and will occupy an important position in the future press market with the improvement of factory automation.

Due to the forming characteristics of the press, its motor operates at high energy efficiency only during a short pressing process. At other stages, the motor has lower energy efficiency and there is a large amount of energy loss. Where a slider rises and falls frequently according to a working rhythm when the press works, the gravitational potential energy and kinetic energy are converted into thermal energy for dissipation during the falling process, which constitutes an important part of energy loss.

SUMMARY

In order to avoid the above-mentioned shortcomings of the prior art, the present disclosure designs an energy-saving double-motor double-station screw press which can switch to a single motor to work when the required power of the press is small; and switch to double motors to work simultaneously when the required power of the press is large. This press is designed to have two pressing mechanisms, which can also improve not only energy efficiency but also working efficiency.

To solve the technical problems, the present disclosure adopts the following technical solution:

an energy-saving double-motor double-station screw press of the present disclosure has the following structural features:

two sets of screw pair mechanisms are respectively arranged on both sides of the press, where a first screw pair mechanism includes a first cylinder, a first lead screw, a first slider, and a first anti-rotation apparatus, and a second screw pair mechanism includes a second cylinder, a second lead screw, a second slider, and a second anti-rotation apparatus; a first differential gear train is formed by a first bevel gear, a second bevel gear, a third bevel gear, and a first turning arm, the first differential gear train takes the third bevel gear and the first turning arm as input ends and the first bevel gear as an output end; and a second differential gear train is formed by a sixth bevel gear, a seventh bevel gear, an eighth bevel gear, and a second turning arm, the second differential gear train takes the eighth bevel gear and the second turning arm as input ends and the sixth bevel gear as an output end;

the first lead screw is driven by a resultant movement which is synthesized by a first motor and a second motor through the first differential gear train; the second lead screw is driven by a resultant movement which is synthesized by the first motor and the second motor through the second differential gear train; and a steering switching apparatus is provided between the second motor and the second differential gear train, so that the steering switching apparatus can drive the eighth bevel gear in the second differential gear train to switch between two different rotation directions, under the condition that a rotation direction of the second motor is not changed;

a first displacement sensor and a second displacement sensor respectively detect and obtain displacements and speeds of the first slider and the second slider, and transmit the information to a control system; a first pressure sensor and a second pressure sensor detect a pressure in a pressing process, and transmit this pressure information to the control system; the control system controls the first motor and the second motor respectively through a first servo driver and a second servo driver, and receives a motor feedback signal; and the first motor and the second motor are both servo motors.

The structural features of the energy-saving double-motor double-station screw press of the present disclosure also lie in: the first motor is directly connected to a first gear, the first gear drives the first turning arm to rotate, the second motor is directly connected to a second gear, the second gear is engaged with a third gear, the third gear is coaxial with a fifth bevel gear, the fifth bevel gear drives the third bevel gear to rotate through a fourth bevel gear; inputs of the third bevel gear and the first turning arm are combined into an output of the first bevel gear through the first differential gear train, the first bevel gear is coaxial with the first lead screw, a rotation movement of the first lead screw is converted into an up-and-down linear movement of the first slider through the first screw pair mechanism; simultaneously, the first turning arm drives the second turning arm to rotate; the steering switching apparatus is provided with a tenth bevel gear and an eleventh bevel gear coaxially with the third gear, and a first clutch is provided between the third gear and the tenth bevel gear, and a second clutch is provided between the third gear and the eleventh bevel gear; the tenth bevel gear and the eleventh bevel gear are engaged with a ninth bevel gear at different positions; when the first clutch is engaged and the second clutch is disengaged, the third gear drives the ninth bevel gear to rotate through the tenth bevel gear; when the first clutch is disengaged and the second clutch is engaged, the third gear drives the ninth bevel gear to rotate through the eleventh bevel gear, the ninth bevel gear drives the eighth bevel gear to rotate, inputs of the eighth bevel gear and the second turning arm are combined into an output of the sixth bevel gear through the second differential gear train, the sixth bevel gear is coaxial with the second lead screw, and a rotation movement of the second lead screw is converted into an up-and-down linear movement of the second slider through the second screw pair mechanism.

The structural features of the energy-saving double-motor double-station screw press of the present disclosure also lie in:

an initial position is set according to the following process:

Step 1: Moving the second slider to a limit position A by working of the first motor, the second motor being not working;

Step 2: Keeping the first motor working, making the second motor work simultaneously, the first clutch being disengaged and the second clutch being engaged, and formula (1) being satisfied, so that the second slider is kept at the limit position A and does not move, and the first slider moves towards a limit position B, and the first motor and the second motor stop working when the first slider reaches the limit position B, to complete setting of the initial position; the limit positions A and B are different limit positions:

n1⁢⁢b=-2⁢n1⁢⁢a·z2⁢a·z2⁢c·z4⁢iz2⁢b·z3⁢b·z4⁢k,(1)

n1ais a rotational speed of the first motor (1a);

n1bis a rotational speed of the second motor (1b);

z2ais the number of teeth of the first gear (2a);

z2bis the number of teeth of the second gear (2b);

z2cis the number of teeth of the third gear (2c);

z3bis the number of teeth of the second turning arm (3b);

z4iis the number of teeth of the ninth bevel gear (4i); and

z4kis the number of teeth of the eleventh bevel gear (4k).

The structural features of the energy-saving double-motor double-station screw press of the present disclosure also lie in: a mode of a no-load operation of the press is set as: the first clutch is engaged and the second clutch is disengaged; the first motor does not work and is locked by a brake; the second motor works alone to complete a no-load stroke of the press. The no-load operation refers to that: the first screw pair mechanism and the second screw pair mechanism are both in a no-load state; the first slider moves upward, and the second slider moves downward correspondingly; or the first slider moves downward and the second slider moves upward correspondingly.

The structural features of the energy-saving double-motor double-station screw press of the present disclosure also lie in: a mode of a load operation of the press is set as: the first clutch is engaged and the second clutch is disengaged; the first motor and the second motor work simultaneously, output powers of the first motor and the second motor are combined on the first differential gear train and the second differential gear train, respectively, thereby controlling operations of the first slider and the second slider to complete a load stroke of the press. The load operation refers to that: Any screw pair mechanism in the press is in a pressing process.

The structural features of the energy-saving double-motor double-station screw press of the present disclosure also lie in: according to a ratio of no-load operation power to load operation power of the press, a power allocation of the first motor and the second motor is performed by formula (2):

p1⁢ap1⁢b=ploadpidle,(2)

p1ais rated power of the first motor;

p1bis rated power of the second motor;

pidleis the no-load operation power of the press; and

ploadis the load operation power of the press;

Compared with the prior art, the present disclosure has the following beneficial effects:

1. The present disclosure connecting two screw pair mechanisms to two motors respectively through different differential gear trains, to implement the complementary actions of execution units of the press, realizing linkage of double execution units. A single execution unit can implement the processing actions twice in one cycle, improving the reusing of kinetic and potential energy and the working efficiency of the press.

2. When the two screw pair mechanisms of the present disclosure are both no-load, since the required power of the press is relatively low, only one motor works, and the load of the motor is in a high-efficiency region, improving the energy efficiency. When any screw pair mechanism is loaded, since the required power of the press is relatively high, two motors work simultaneously, and the two motors are in high-efficiency regions and have high energy efficiencies, respectively. Meanwhile, the powers of the two motors are combined, so that the installed powers of the motors can be reduced under the condition of meeting the maximum required power of the press.

