RU199898U1 - ADAPTIVE CONTROL SYSTEM OF HYDRAULIC CYLINDER FEEDING THE POWER UNIT HEAD FOR MACHINING MACHINE - Google Patents

Abstract

The utility model relates to the equipment of machine-building industries for mechanical processing of materials and can be used in the power heads of the aggregate machine tools. The adaptive control system of the hydraulic cylinder for feeding the power head of the machine tool for machining contains a torque transducer made with the possibility of being connected to the electric motor of the drive of rotation of the spindle of the head and associated with an axial control throttle. The throttle is made with control and controlled cavities with the possibility of corresponding connection of the controlled cavity with the hydraulic cylinder and through the control panel with the pumping station and with the possibility of controlling the speed of the hydraulic feed cylinder. The measuring transducer is made in the form of a rotor located in a stationary collector, made with the possibility of coaxial connection with a rotating part of the above-mentioned electric motor, and placed in the through radial bore of the rotor of the housing and movable stops installed with the possibility of adjusting the given position of the housing in the bore by means of screws located in the covers of the radial bore of the rotor. In the housing, two nozzles with measuring chambers are arranged coaxially towards each other with the possibility of adjusting the axial position, between which there is a movable inertial damper spring-loaded on both sides, and on the other side of the nozzles there are constant throttles. The nozzles and constant chokes are connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line for supplying the working medium with the control panel, the cavity of the body between the nozzles is connected to the line of the working medium, and the measuring chambers of the nozzles are connected by control lines to the control cavities located under the ends the presence of new elements and functional connections allows to increase the accuracy of tuning the control system to a given operating mode, adapt the feed cylinder of the power unit head to changing conditions of material processing on the machine and expand the technical capabilities of the adaptive control system for the hydraulic cylinder of the machine for machining by adjusting the power and speed parameters of cutting in wide ranges.

Description

The utility model refers to the equipment of machine-building industries and can be used in the machining of materials on modular machines with adaptive control of the power head feed.

Known control systems for power aggregate heads, in which hydraulic panels are used for targeted purposes, containing built-in guides and control devices. The nominal axial force on the cutting tool is determined by the presetting of the safety or pressure reducing valve for a given pressure in the working cavity of the piston hydraulic cylinder of the head feed, and the forward movement speed (feed) of the tool is determined by setting the throttle or variable pump for a given flow rate of the liquid supplied to the cylinder or removed from into the tank. Control is carried out "along the way", that is, by moving the head, for which they use adjustable or constant stops interacting with limit switches or valve control levers. The system settings are not changed during operation. The drives of the main movement and feed work independently of each other [1].

The disadvantage of such control systems is the lack of adaptation of hydraulic cylinders for supplying power aggregate heads to the changing conditions of machining materials on the machine.

Known is an adaptive feed control system for a self-acting power head of an aggregate machine, comprising a slide control valve installed at the inlet or outlet of a hydraulic feed cylinder, in which the control cavities of the hydraulic lines are connected to the cylinder cavities [2].

The disadvantage of the system is that it changes the feed for any change in the load on the cylinder rod, which can be caused by various reasons: changes in processing conditions, changes in the friction forces in the cylinder and the guides of the housing and base, changes in internal fluid leaks in the cylinder, and others. The accuracy of setting the specified mode of material processing on the machine is not ensured.

As a prototype, an adaptive control system for the supply of a power unit head is adopted, containing in the drive of the main movement a torque measuring transducer made in the form of a dynamometric drive (drive toriometer), which is connected by a mechanical spring-rack and pinion gear with an axial control throttle mounted on the drain from the hydraulic cylinder filing [3].

Analysis of the prototype shows that the design of the torque measuring transducer in the form of a torque drive (drive toriometer) with a mechanical spring-rack and pinion transmission does not ensure the accuracy of tuning the system to a given operating mode, has a complex design and limits the technical capabilities of the power head.

The technical problem to be solved by the claimed utility model is to improve the accuracy of tuning the adaptive control system of the hydraulic cylinder feeding the power unit head of the machine tool for machining materials to a given operating mode and expanding the technical capabilities of the mentioned control system by adjusting the power and speed parameters of cutting in wide ranges.

The solution to this problem is achieved by the fact that the measuring transducer is made in the form of a rotor located in a stationary collector, made with the possibility of coaxial connection with the rotating part of the electric motor, and placed in the radial through bore of the housing rotor and movable stops installed with the possibility of adjusting the given position of the housing in the bore by screws located in the covers of the radial bore of the rotor, while in the housing two nozzles with measuring chambers are located coaxially towards each other with the possibility of adjusting the axial position, between which there is a movable inertial damper spring-loaded on both sides, and on the other side of the nozzles there are constant throttles, and nozzles and constant chokes are connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line of supply of the working medium to the control panel, the cavity of the body between the nozzles is connected to the line of the working medium, and The control chambers of the nozzles are connected by control lines with control cavities located under the ends of the movable element of the axial control throttle.

Comparison of the claimed adaptive control system of the hydraulic cylinder for feeding the power unit head of the machine tool for machining with the prototype shows that there are new parts and functional connections between them.

New parts: torque measuring transducer in the form of a rotor located in a stationary collector, made with the possibility of coaxial connection with the rotating part of the electric motor of the drive of rotation of the spindle of the power unit head;

housing and movable stops located in the through radial bore of the converter rotor with the possibility of adjusting the predetermined position of the housing in the bore by means of screws located in the covers of the radial bore of the rotor;

two nozzles with measuring chambers located in the housing coaxially towards each other with the possibility of adjusting the axial position, between which there is a movable inertial damper spring-loaded on both sides, and on the other side of the nozzles there are constant throttles;

nozzles and constant chokes connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line of supply of the working medium to the control panel, the cavity of the body between the nozzles is connected to the line of the working medium, and the measuring chambers of the nozzles are connected by control lines to the control cavities located under ends of the movable element of the axial control throttle.

New functional connections: a torque measuring transducer in the form of a rotor located in a stationary collector, coaxially connected to the rotating part of the electric motor of the spindle rotation drive, provides high sensitivity and accuracy of tuning the adaptive control system to a given operating mode of the power unit head and expanding the technical capabilities of the control system, so how allows you to accurately assess the change in the moment of resistance to the rotation of the spindle of the power unit head by changing the angular speed of the rotating part of the electric motor;

the housing and movable stops located in the through radial bore of the rotor provide the ability to accurately set and fix the given position of the housing in the bore by means of screws,

located in the caps of the radial bore, which determines the sensitivity and controlled range of changes in the parameters of material processing on the machine;

nozzles and constant chokes connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line of supply of the working medium to the control panel, the cavity of the body between the nozzles is connected to the line of the working medium, and the measuring chambers of the nozzles are connected by control lines to the control cavities located under the ends of the movable element of the axial control throttle, convert the input signal in the form of a change in the angular speed of the rotating part of the electric motor into a control signal in the form of a pressure difference of the working medium under the ends of the movable element of the axial control throttle; the bridge circuit for connecting nozzles and constant chokes provides maximum sensitivity and accuracy of the torque transducer.

The presence of new parts and functional connections between them increases the accuracy of tuning the adaptive control system of the hydraulic cylinder for feeding the power unit head of the machine for machining materials to a given operating mode and expands the technical capabilities of the mentioned control system by adjusting the power and speed parameters of cutting in wide ranges.

FIG. 1 shows a structural diagram of a power unit head of a machine tool for machining with an adaptive control system for a hydraulic feed cylinder in the initial position, before tuning to a given operating mode.

The adaptive control system of the hydraulic cylinder 1 for feeding the power unit head of the machine tool for machining comprises a torque measuring transducer 2 configured to be connected to the electric motor 3 of the drive for the rotation of the spindle 4 of the said head and connected to the axial control throttle 5. The mentioned throttle is made with control valves 6, 7 and controlled by 8 cavities with the possibility of corresponding connection of the controlled cavity with the said hydraulic cylinder and through the control panel 9 with the pumping station 10 with the possibility of controlling the speed of the hydraulic supply cylinder.

The torque measuring transducer is made in the form of a rotor 12 located in the stationary collector 11, made with the possibility of coaxial connection with the rotating part of the said electric motor. In the through radial bore of the rotor housing 13 and movable stops 14 and 15 are placed, installed with the possibility of adjusting the predetermined position of the housing in the bore by means of screws 16 and 17 located in the covers 18 and 19 of the radial bore of the rotor. The nozzles 20 and 21 with the measuring chambers 22 and 23 are arranged coaxially towards each other with the possibility of adjusting the axial position of the measuring chambers 22 and 23, between which there is a movable inertial damper 24 spring-loaded on both sides, and on the other side of the nozzles there are fixed throttles 25 and 26. Nozzles and constant the chokes are connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line 27 for supplying the working medium with the said control panel, the cavity 28 of the body between the nozzles is connected to the line 29 for removing the working medium, and the measuring chambers of the nozzles are connected by control lines 30 and 31 with the said control cavities located under the ends of the movable element 32 of the axial control throttle.

The torque transducer has a radial X-X sensitivity axis,

The adaptive control system of the hydraulic cylinder of the power head of the machine tool for machining works as follows.

The operating cycle of the power head is adjusted by setting the stops and limit switches to a predetermined position, which control the operation of the hydraulic guiding devices (not shown in Fig. 1), located in the panel 9, control "along the way" is implemented.

The frequency of rotation of the spindle 4 of the head is not regulated and is determined by the frequency of rotation of the shaft of the electric motor 3. With an increase in the moment of resistance on the spindle, the angular speed of the rotating part of the electric motor decreases.

The idle speed of the power head when the tool is brought to the workpiece and when the tool is retracted to its original position is adjusted by adjusting the flow rate of the working medium supplied to the hydraulic cylinder 1 of the feed and removed from it to the drain through the axial control throttle 5.

The pressure of the working medium in the supply line of the cylinder from the pumping station 10 is limited by setting the safety valve (not shown in Fig. 1) located in the control panel 9.

The presetting of the torque transducer is a two-step process.

The first stage provides for the installation of a movable inertial damper 24 in the geometric center of the housing 13, for which the position of the nozzles 20 and 21 along the axis of sensitivity X-X and the preload of the centering springs are simultaneously adjusted. The gaps between the ends of the nozzles and the flap must be the same.

The damper mass and spring forces determine the sensitivity of the transmitter. This setting can be made outside the rotor 12.

The second stage involves the installation of the geometric center of the housing 13 in the radial bore of the transducer rotor at a certain predetermined distance from the axis of rotation, for which the position of the movable stops 14 and 15 is fixed with screws 16 and 17 and the locknuts are fixed. The value of the adjusted eccentricity determines the sensitivity of the measuring transducer. By changing the eccentricity, the transmitter can be tuned to different ranges of torque measurement.

When the head is in operation, the working medium from the pumping station through the control panel enters the piston (left) cavity of the hydraulic feed cylinder, and from the rod (right) cavity is drained to the tank. The movable power head together with the cylinder body moves from right to left.

For the operation of the measuring transducer, the working medium from the supply line 27 through the collector 11 enters through constant throttles 25 and 26 into the measuring chambers 22 and 23 of the nozzles, and then, passing resistance in the form of gaps between the ends of the nozzles and the inertial damper, from the cavity 28 of the body along the line 29 drainage of the working medium is drained into the tank.

When the rotor of the transducer rotates, connected to the rotating part of the electric motor, a centrifugal force of inertia arises, directed along the axis of sensitivity X-X. The centrifugal force of inertia is proportional to the mass of the damper, the value of the adjusted eccentricity and the square of the angular speed of the converter rotor.

Under the action of this force, the inertial flap is displaced and changes the hydraulic resistance of the gaps between its ends and the ends of the nozzles.

If the resistance to the outflow of the working medium from the nozzle 20 increases, and from the nozzle 21 decreases, then the pressure in the measuring chamber 22 increases, and the pressure in the chamber 23 decreases. The resulting pressure difference is used as a control signal in the control cavities 6 and 7 under the ends of the movable element 32 of the axial control throttle.

In the proposed control system, the axial control throttle can be made in the form of a four-slot spool valve with spring centering, as shown in FIG. 1.

Under the influence of the pressure difference in the control lines 30 and 31 and in the control cavities 6 and 7, the movable element of the axial control throttle is shifted to the left, setting the flow cross-sections of the working medium inlet and outlet slots corresponding to the idle speed of the power unit head.

With an increase in the torque of resistance to rotation on the spindle, the rotor speed and the inertia force decrease, the flap moves towards the nozzle 21. This disturbs the balance of forces on the movable element of the axial control throttle, it shifts to the right, setting the passage sections of the slots corresponding to the speed of the working feed.

In the future, any change in the moment of resistance to the rotation of the spindle of the power unit head will lead to a corresponding change in feed (an increase in the moment of resistance will lead to a decrease in feed, and a decrease in the moment of resistance will lead to an increase in feed), that is, the operation of the hydraulic feed cylinder will adapt to changes in processing conditions material on the machine.

After completing the processing of the part on the machine, the working medium from the pumping station through the control panel is fed into the rod (right) cavity of the hydraulic cylinder, and from the piston (left) cavity it is discharged to the drain into the tank. The powerhead returns to its original position. Further, usually, the cycle of work is repeated.

Improving the tuning accuracy of the adaptive control system of the hydraulic cylinder for feeding the power aggregate head of the machine tool for machining to a given operating mode and expanding the technical capabilities of the said control system is achieved by using the torque of the electric motor of the spindle rotation drive of the head to control the hydraulic cylinder, which is carried out by means of a measuring transducer damper type and axial control throttle.

Sources of information taken into account

1. Sveshnikov V.K., Usov A.A. Machine hydraulic drives: Handbook. - 2nd ed., Rev. and add. - M .: Mechanical Engineering, 1988. - S. 191, fig. 5.38, pp. 288-289, fig. 7.8.

2. Bektibai B.Zh. Development of a universal adaptive automatic system for controlling the operating modes of hydraulic power heads of machine tools. - Abstract dissertation ... cand. tech. sciences. - Republic of Kazakhstan, Almaty, Kazakh National Technical University. Kanyna Satpayeva, 2001. - S. 6-7, fig. 1.

3. Tverskoy M.M. Stabilization of the load on the drill during deep drilling with multi-spindle machining. - In the book. Self-adjusting machines / Ed. B.S. Balakshin. - M .: Mechanical Engineering, 1970. - S. 259-262, fig. 1 and 2 (prototype).

Claims (1)

An adaptive control system for a hydraulic cylinder for supplying a power unit head of a machine tool for machining, comprising a torque transducer configured to be connected to an electric motor for driving a spindle of said head and connected to an axial regulating throttle made with control and controlled cavities with the possibility of corresponding connection of the controlled cavity with the said hydraulic cylinder and through the control panel with a pumping station with the ability to control the speed of the hydraulic feed cylinder, characterized in that the said measuring transducer is made in the form of a rotor located in a stationary collector made with the possibility of coaxial connection with the rotating part of the said electric motor, and placed in the through radial bore of the housing rotor and movable stops installed with the possibility of adjusting the given position of the housing in the bore by means of ntov, located in the covers of the radial bore of the rotor, while in the housing are located coaxially towards each other with the possibility of adjusting the axial position of two nozzles with measuring chambers, between which there is a movable inertial damper spring-loaded on both sides, and on the other side of the nozzles there are constant throttles, and nozzles and constant chokes are connected by a bridge circuit, in which the body cavities in front of the constant chokes are connected by a line for supplying the working medium with the control panel, the cavity of the body between the nozzles is connected to the outlet line of the working medium, and the measuring chambers of the nozzles are connected by control lines with control cavities located under the ends moving element of the axial control throttle.

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