SU648446A1 - Braking regulator for movable crossbeam of hydraulic press - Google Patents

Description

(54) MOBILE BRAKING REGULATOR

HYDRAULIC PRESS CROSSBARS

precision forging by ensuring the braking of a movable cross member with constant acceleration. The goal is to achieve that the controller, containing the output parameter sensor, driver, comparison units, power, working and damping electric motors, gearbox and hydraulic booster, has a computing device of kinetic energy of a mobile cross member, made in the form of two AC tachogenerators connected mechanically with a movable cross bar and electrically interconnected. As tachogenerators are used asynchronous motors with a hollow rotor. In order to increase stability, in the area around the middle position of the output shaft of the hydraulic booster, the computing device is made with proportional negative feedback in the form of a selsyn, mechanically connected with the output rod of the hydraulic booster.

FIG. 1 is a block diagram of a brake regulator for a movable cross member of a hydraulic press; in fig. Figure 2 shows graphs of the speed of the cross member as a function of the path. The deceleration controller contains the output parameter sensor 1 (movement coordinates of the movable cross member), driver 2, signal output parameter comparison unit 3 and driver settings, signal comparison unit 4, power amplifier 5, working motor 6, gearbox 7, hydraulic booster 8, damping an electric motor 9, a computing device consisting iis proportional to negative feedback 10, in the form of a selsyn mechanically connected to the output shaft of the hydraulic booster 8, a switching unit 11 proportional negative ion feedback 10, an alternating current tachogenerator 12, a phase 13 reverse unit of an output voltage of a tachogenerator 12, supplied from a separate source (not shown) of an alternating current tachogenerator 14.

When a block 4 is received at the input, in addition to the signal proportional to the coordinate of the moving pole, and the signal proportional to the square of the current speed value, the crossbar will be decelerated at a constant rate of 7 tons, e.

dV,

  const ...

-01p dt

and the change in the speed of movement of the cross-piece as it approaches the pre-parabolic

This is due to the law (Fig. 2).

L H2a, ... (2)

where 5n is the rest of the way, which the crossbar must pass to the given reverse point. Cross Bar Slow Time

Vnn-y

V

by

PC

by

(3)

ptah

n max

where by, Vf, k is the initial and final velocity of the cross member. From consideration of FIG. 2a, it is clear that the slope of the characteristic UP 1 (the zone near zero is very large and tends to infinity. As a result, the cumulative gain of the automatic press control system in which the proposed regulator will be applied will exceed the critical value in this zone stability. To eliminate this disadvantage, the characteristics of the CB,) should correspond to: dependencies (fig.2b).

-K5 „at (5p (6po)

Yn

Ci

1–2а „5; with (b„ 1 (5p)

where is the critical gain

Sr, - - break point characteristics ..

The first of these equations characterizes a linear dependence of the speed on the movement of the cross member, and the operation of the device is carried out by switching on in the interval (6its, Evil) proportional to the negative feedback on the position of the output hydraulic booster 8, made in the form of a selsyn, mechanically connected to the output stock hydraulic booster.

The second equation is nonlinear, which characterizes the operation of the device in the interval (Snol / C rt) by quadratic feedback on the current value of the crossbar speed, proportional to negative feedback 10 in this interval is turned off using block 11.

In order to consider the operation of the device, we assume that the movable cross member is above the forging, in accordance with the established task. In this case, Uj- U Oh, the rotor of the electric motor 6 is stationary, the output rod of the hydraulic booster 8 occupies a middle position, the press valves are buried and the cross member is stationary. When introducing a new task, the equality of the signal difference to zero is violated, as a result of which the rotor of the electric motor 6, smoothly gaining speed, due to the influence of the damping motor 9, moves the stem of the input spool of the hydraulic booster 8 to the extreme position corresponding to the opening of the valves controlling the cross-member movement down the signal TJr is equal to zero (when deviating from the average position of the output rod of the hydraulic booster 8, using the switch unit 11, the negative feedback 10 is proportional is turned off, and IT is determined by the magnitude of the square of the crossbar movement speed, however, it is less than I. When the crossbar reaches the point at which the rest of the way to the given coordinate will be equal to the braking path, the signal will decrease to the value TJ, and further movement of the crossbar will cause the rotor of the electric motor 6 to rotate in the opposite direction , but the speed of its rotation in this case is determined by the rate of change of Uj and U KV, wherein the value of the braking path is determined by the value of the square of the initial velocity of the cross member.

The upward movement of the crossmember is similar, only in this case, the phase of the output voltage of the tachogenerator 12 to 180 is changed by means of block 13, and the output shaft of the hydraulic booster 8 is moved to the opposite extreme position. The insensitivity of the regulator is determined by the slope of the signal proportional to the negative feedback 11.

When using the computing device of the crossbar kinetic energy, the way to slow it down when approaching a given coordinate is determined by the value of the initial kinetic energy. As a result, a significant gain is achieved.

over time, by reducing the braking time of the cross member during the stretching process, which is 6570% of the machine press time, the press capacity increases by about 25% while maintaining its unaccented operation. The introduction of the proposed invention on a hydraulic press according to preliminary calculations will allow to obtain an annual economic effect of 100-200 thousand rubles.

Claims (2)

1. The braking regulator of the movable cross member of the hydraulic press, containing the output parameter sensor, driver, comparison units, power amplifier, working and damping electric motors, gearbox and hydraulic booster mechanically associated with crossbar motion control valves, characterized in that, in order to improve press performance and forging accuracy by ensuring deceleration of a movable cross-beam with constant acceleration, it is equipped with a computing device of the kinetic energy of a movable cross-beam, made in the form of two alternating current tachogenerators connected mechanically to the movable cross-member of the press and electrically interconnected. 2. Regulator on; P . 1, characterized in that the computing device is made with a proportional negative inverse coupling in the form of a selsyn, mechanically connected with the output rod of the hydraulic booster. Sources of information taken into account in the examination: 1. Author's certificate of the USSR 176171, cl. B 30 V 15/20, 1962. 2. USSR author's certificate number 39939S, cl. B 30 B 15/20, 1972. oa n no s