SU436665A1 - Device for moving the cutting press carriage - Google Patents

Description

one

The invention of the machine industry is for light industry and can be used in cutting presses with a mixed carriage.

In known automatic presses designed to cut down parts of light industry products, the control signal from the software of the monitor is amplified by hydraulic, pneumatic or electric amplifiers and is realized in the form of carriage movements, as a rule, using the lead screw.

When operating in start-stop and reverse modes, dynamic mismatch errors occur in known directions, which leads to an increase in the production of poor-quality products, control systems of such presses in most cases cannot be built in a simple open circuit with additional feedback loops. This complicates the design of the press and, therefore, increases its cost.

These drawbacks can be eliminated by introducing into the design of the carriage drive assembly a device that provides a kinematic connection between elements of the press control system.

The proposed device is a torque adder, made in the form of a threaded spindle and a nut, connected by means of rotating guides and a worm with a drive shaft. The adder screw is connected by means of a self-brake transmission (screw) to the output link of the articulated-rod switching power amplifier, consisting of

Four seven-link mechanisms with two driving links, one of which is connected to the power engine and the other to the source of control signals. In this case, the structure of the amplifier allows to obtain significant

the output power when small power is consumed for control, since the parameters and the number of seven-part mechanisms are chosen from the conditions of ensuring the minimum value of the average integral moment,

required to move the control link in the range corresponding to the first work of the press.

FIG. 1 shows a block diagram of a device for moving a carriage; na

FIG. 2 - plan of the seven-part Aiehanism; in fig. 3 - graphs illustrating

power and kinematic relations in

hinge pulse amplifier

power.

The device for moving the carriage consists of a drive shaft 1, which transmits the movement of the worm gear 2, the guide 3 and the nut 4. On the nut there is a holder 5 of a single bearing fixed to the nut. The top 6 of this bearing is rigidly connected to the carriage 7 moving along the fixed guides 8. The lead screw 9 of the adder is connected by means of a self-braking worm gear 10 with a hinged rod power amplifier 11. The amplifier contains four seven-part mechanisms (Fig. 1, 2), eccentricities of the drive units in which are located on the drive, the nominal shaft with an interval of 0.5 rad.

These mechanisms are connected through the overrunning clutches 12 to a worm of a self-braking transmission. The carriage movement is controlled by a source of low-power signals — in this case, a cam 13. In addition, the device contains ni-tunes 14, 15, 16 kinematically associated with the half-coupling 17, and the control link 18.

Consider the operation of the amplifier and the adder, given PA figures. 1-3. Corresponding forces R 14c, R 15c and R 16c acting on the hinge pin C from the connecting rods 14, 15, 16 can be set with the help of a power triangle, since the torque of the counter arm (M), applied to the leading coupling half 17, is known clutches and directions of these forces. Analyzing it, it can be noted that the reaction of R 14c and R 15c. Consequently, the force and moment required for turning the control link 18 will also be significantly less than the force R 15, 17 and the moment M R 15, 17 required to move the driving half-coupling of the amplifier's free-wheeling mechanism. This is achieved by the design of the 7th kinematic chain in which the hinge A is located on the extension of the connecting rod 15 in the position corresponding to the maximum value of the angular velocity of the coupling half 17. In addition, in this position the hinge E must coincide with the kinematic pair C, and the mechanism parameters are selected ensuring minimum pressure angles. In the first approximation, we can assume that, if there is a constant moment of resistance M,

The self-brake transmission applied to the screw, which is the output link of the amplifier, the moment of resistance M appearing on the control link will vary in accordance with the character of the dependence M (f) (Fig. 3). It can be seen from the graph that the required control moment, and consequently, the power can be reduced not only due to the special design of the seven-link mechanism, but also due to an increase in their number.

The position of the control link of the amplifier determines the value of the average integral angular velocity wg of the screw of the adder. The latter may vary in the range

Makssr - Yamin Wed SPEED OF NUTS

to. : 0.5 ((0 „-4- CD ,,); - const. Max sGmin

In accordance with its functional purpose, the adder determines the same direction of rotation of the elements of a screw pair, therefore the carriage speed is a function of the difference between the angular velocities of the screw and nut, as well as the diameter of the screw and the tangent of the helical slope.

PRE D MEET and 3 o breteni

A device for moving a carriage of a cutting press containing an executive mechanism connected through a power amplifier to a source of control signals and through a drive shaft with a power engine, characterized in that, in order to improve product quality and save materials, the actuator is

a screw adder consisting of a spindle and a rotating nut, kinematically, with a carriage and a drive shaft, and the power amplifier includes four seven-piece mechanisms with two

The links, one of which is connected with the drive shaft, and the other with the source of control signals, the driving screw of the adder being connected through a self-braking transmission to the output link of the power amplifier.

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