SU1209434A1 - Device for controlling position of working members - Google Patents

Description

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The invention relates to wood-processing industry and: can be applied in machine tools with numerical control.

The purpose of the invention is to simplify the design and improve positioning accuracy.

Figure 1 shows the principal hydrokinetic scheme of the device; Fig. 2 is a velocity change diagram during the positioning process; FIG. 3 is a block diagram of the device; FIG. 4 is a rough electrical diagram.

The movement of the working body (support) 1 along the guides 2 of the axle is an actuating mechanism (hydraulic cylinder) 3 (FIG. I).

The control of the displacement value with indication of the current coordinate on the display panel is performed with the help of a non-contact sensor of the position of the working device (selsyn) 4 installed coaxially with the screw 5 of the reversible screw feedback mechanism. The nut 6 of the screw mechanism is fixed in the support 1, and the screw 5 is mounted in the radial-resistant ball bearings 7 fixed in the axial direction. When the caliper and nut are moved progressively, the screw 5 is rotated in ball bearings: one full turn of the screw 5 and associated with it by means of the back joint without a backlash 8 of the rosin 4 corresponds to the thread pitch S.

To eliminate gaps in the screw feedback mechanism, the nut 6 is made of two half nuts, one of which has the possibility of axial adjustment.

The hydraulic system of the device is powered by a constant-capacity pump 9.

A three-position reversing valve 10 with electromagnets Em 1 and Em 2 is installed in the pressure line to control the direction of movement and stopping at the discharge line.

In order to increase the accuracy of installation on the size and fast-speed, the hydraulic system is complete with three speeds with automatic switching over

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as approaching a given coordinate, first to the intermediate, and then to the installation speed of the slow approach of VH (Fig. 2). To do this, a three-position hydraulic valve 11 with electromagnets Em 3 and Em 4 and two flow controllers 12 and 13 are installed in the drain line.

When switching on the electromagnet Em 4 (with de-energized Em 3), the oil enters the drain through the open line 14 and the caliper 1 moves with the highest speed Vy, determined by the performance of the pump 9.

When the electromagnet is turned on, the EM 3 (when the EM 4j is de-energized, the drain line is connected to the tank through both flow regulators 12 and 13, which ensures that the support 1 moves at an intermediate speed Vnp.

With the electromagnets EM 3 and EM 4 de-energized, the plunger of the hydraulic distributor I1 occupies the middle (neutral) position. As a result, the oil enters the drain only through the flow controller 13, which is tuned to the speed of the slow VM flow.

The page of the circuit diagram of the device (Fig. 3) includes a digital display device (UPI), consisting of a console 15 preset of coordinates

with decadal switches, 16 display panels on gas discharge

lamps, processing unit 17 and output relay unit 18, unit 19 of thyristor triac amplifiers, switching electromagnets Em 1 - Em 4 three-way control valves 10 and 11 controlling the direction and speed of movement of the hydraulic cylinder 3. The amount of movement of the support 1 is controlled by contactless selsyn 4 by means of a reversible screw mechanism 5, 6 feedback. The signal from the selsyn on the feedback channel enters the data processing unit 17 AML) DRO.

The principal electrical circuit of the device (Fig. 4) controls the electromagnets Em I - Em 4 three - position hydraulic distributors 10 and 11 (Fig.) Using the contacts of low current relays K 1 - K 14 of the block 18 of the output relays of the digital display device (DRO). The DRO consists of a block 17 of data processing (AML), to which. A non-contact selsyn 4, remote control preset 15 and display panel 16 are connected to it.

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The closing contacts of the relay K 1 - K 4 are located in the control circuits of symmetric thyristors (triacs) V 1 - V 4, which commute the coils of electromagnets Em 1 - Em A of the hydraulic distributors. The additional resistances R 1 limit the amount of control current required to open the contactless triac.

The device works as follows.

The operator dials the required coordinate Xs of the support 1, using the decade switches of the dial-up field of the DRO control panel 15 (Fig. 3). The entered coordinate is displayed on the display panel 16.

Depending on the coordinate of the positioning point relative to the selected reference point at the output of the data processing unit 17, the relay K 1 (move to the right) or K 2 (move to the left) and relay K 4 triggers. The corresponding electromagnets EM 1 are turned on; or Em 2 and Em 4 of the control valves 10 and 11, and the caliper I begins to move in a given direction with the highest speed Vo, determined by the performance of the pump 9.

The progressive movement of the caliper 1 is converted into the corresponding angle of rotation of the rotor of the contactless selsyns 4, which controls the actual coordinate at each time point. The feedback signal from selsyn 4 is fed to the AML 17 DRO, where it is mapped to a given coordinate Xj.

As the caliper 1 approaches the predetermined Xj coordinate, it operates 10

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The relay K 3 and releases relay K 4. In this case, the hydraulic actuator switches to intermediate speed Vnp. When the relay K 3 is released, the hydraulic actuator switches to the slow feed speed V, This speed is selected depending on the required positioning accuracy.

When the actual coordinate of the caliper Hf coincides with the given X, the relay K 1 or K 2 is automatically switched off, the corresponding symotor of the block 19 is locked and the corresponding electromagnet Em 1 and Em 2 of the hydraulic distributor 10 is turned off. 3 from the hydraulic system. In this case, the support 1 stops at a predetermined position, and its actual coordinate is displayed on the DRO display panel 16.

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The proposed device makes it possible to increase the installation accuracy of the movable working member at the predetermined positions due to the fact that a reversible screw transmission to the measuring transducer allows completely eliminating kinematic gaps. The pitch of the screw S of the reversible screw mechanism is several times smaller than the pitch diameter of the pinion gear - Da m Z, which leads to an increase in the sensitivity and accuracy of the development of the specified movements.

In addition, the installation of a reversible screw mechanism nut in cynnop-t te provides a simplified design.

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VNIIPI Order 3.72 / 20 Circulation 502 Subscription

Branch PPP Patent, Uzhgorod, Proektna St., 4

Claims (1)

DEVICE FOR CONTROL OF POSITION OF WORKING BODIES, including an actuator having a non-contact rotary position sensor of the working body and a feedback mechanism, which differs in that, in order to simplify the design and improve positioning accuracy, the feedback mechanism is made in the form of a reversible screw gear, the screw of which is mounted axially in the bearings motionless and connected at one end to a nut fixed in a movable working body, and at the other end to a rotor of a contactless sensor ka working body position. & 1 12094