CN112296853A

CN112296853A - Automatic PE ball core polishing system based on torque control and control method

Info

Publication number: CN112296853A
Application number: CN202010697967.5A
Authority: CN
Inventors: 何致远; 王利军; 王子辉
Original assignee: Zhejiang Lover Health Science and Technology Development Co Ltd
Current assignee: Zhejiang Lover Health Science and Technology Development Co Ltd; Zhejiang University of Science and Technology ZUST
Priority date: 2020-07-20
Filing date: 2020-07-20
Publication date: 2021-02-02
Anticipated expiration: 2040-07-20
Also published as: CN112296853B

Abstract

The invention discloses a PE ball core automatic polishing system based on torque control and a control method. The problems of complex structure, high operation requirement and low applicability of PE ball core polishing equipment in the prior art are solved. The system comprises a supporting frame, wherein a ball core rotating mechanism for clamping the PE ball core is arranged in the supporting frame, and a two-degree-of-freedom motion mechanism is arranged at the upper part of the supporting frame; the two-degree-of-freedom motion mechanism comprises a first motion component and a second motion component, and the first motion component is arranged on the support frame in a sliding mode through the ball core positioning mechanism; the polishing mechanism is arranged on the second moving assembly and comprises a polishing cloth wheel, and the polishing cloth wheel does circular motion along the surface of the PE ball core. The polishing is carried out according to the sequence of ball core clamping, ball core positioning, parameter setting, ball core polishing and stopping resetting. The invention automatically finishes the polishing of the PE ball core, has simple operation, low requirements on the operation experience and the technical level of operators, wide applicability range and ensures high polishing precision.

Description

Automatic PE ball core polishing system based on torque control and control method

Technical Field

The invention relates to the technical field of polishing, in particular to a PE (polyethylene) ball core automatic polishing system based on torque control and a control method.

Background

Along with the rapid promotion of the urbanization process of China, the popularization rate of pipeline gas is higher and higher. Traditional gas pipeline parts (including pipeline, valve, crossover sub, flange, bolt, nut gasket etc.) all adopt metal material processing to form basically, and its biggest shortcoming is just easily corroded (including corrodes such as soil, bacterium, chemistry, electrochemistry), need do anticorrosive treatment and routine maintenance to metal pipeline parts, has not only increased the operation cost, still can't thoroughly avoid the gas pipeline leakproofness potential safety hazard that is caused by corroding in addition. To effectively avoid the corrosion problem, Polyethylene (PE) has been used as a material for gas pipe parts since the last 80 th century. At present, PE materials are widely used in gas delivery pipe networks due to the characteristics of stable physical and chemical properties and convenient installation and maintenance.

As an important part of PE gas pipeline components, PE ball valves are increasingly used and valued as pipeline control elements. Compared with the traditional metal ball valve, the PE ball valve has the following outstanding advantages: (1) the chemical corrosion resistance is excellent, an anticorrosive layer is not needed, the maintenance is not needed, and the service life is long; (2) the valve shell is convenient to construct, stable in safety sealing performance, and high in welding strength, and compared with rubber gasket type or mechanical type joints, the valve shell is free of danger of external leakage caused by joint distortion; (3) the operating torque and the pressure loss are small, the inner wall of the valve is smooth and has full drift diameter, the friction resistance is ultralow, and scaling is not easy to occur; (4) the high-toughness high-strength composite pipe has high toughness, strong capacity of adapting to uneven settlement of pipe bases, and seismic resistance, Slow Crack Growth (SCG) resistance and Rapid Crack Propagation (RCP) resistance.

Compared with a metal ball valve, the machining process of the PE ball valve is more complex, and especially the polishing process requirement on the PE ball core of the core part in the PE ball valve is higher. The polishing precision (including roundness and surface roughness indexes) of the PE ball core directly determines the sealing performance, the stability of the operating torque of the ball core and the linear expansion coefficient of the PE ball valve.

At present, the polishing process of the PE ball core in the industry still takes the manual polishing mode as the main mode, the polishing mode wastes time and labor, the efficiency is low, the consistency of the polishing precision cannot be guaranteed, and meanwhile, the dust generated in the polishing process causes harm to the health of operators. Some researchers in academia have proposed some polishing or grinding schemes for ball valve spools, such as those in the institute of zheng-state academy of technology who has proposed a "BQ-type double eccentric half ball valve spool grinder", which aims to solve the serious uneven phenomena of material removal, abrasion, grinding and the like caused by the difference of grinding tracks between the center point and the edge point of a spherical surface, and the grinding, abrasion and the like of the whole spherical surface are uniform and consistent by actively and constantly changing the position of the spool. However, in order to realize the real-time change of the position of the valve core, the polishing mechanism adopts a plurality of complex parts and mechanisms such as a speed regulating motor of a worm and gear speed reducer, a planetary speed reducer, a bevel gear, a crank (cam) push rod sine mechanism, a rack and gear mechanism and the like, so that the polishing mechanism not only has high equipment cost and large energy consumption loss, but also has very high requirements on processing assembly and field operation. Wanlanxi et al, the lanzhou institute of landification, china, proposed a ball valve ball grinder, which rotates a grinding block along with a ball valve according to the machining characteristics of the ball and the cutting motion trajectory of grinding, and grinds the ball valve by generating friction torque according to friction force and eccentricity caused by inertia during rotation. Although the ball valve polishing machine has simple structure, fewer parts and is easy to machine, manufacture and assemble the whole machine, the eccentric rotation working principle of the ball valve polishing machine determines that the ball valve polishing machine is not suitable for the PE ball core polishing process which is produced by an injection molding process and has rough and uneven spherical surface.

Disclosure of Invention

The invention mainly solves the problems of complex structure, high operation requirement and low applicability of PE ball core polishing equipment in the prior art, and provides a PE ball core automatic polishing system based on torque control and a control method.

The technical problem of the invention is mainly solved by the following technical scheme: a PE ball core automatic polishing system based on torque control comprises,

the support frame is internally provided with a ball core rotating mechanism for clamping the PE ball core, and the upper part of the support frame is provided with a two-degree-of-freedom movement mechanism;

the two-degree-of-freedom motion mechanism comprises a first motion component which does circular motion and a second motion component which is arranged on the first motion component and does radial motion, and the first motion component is arranged on the support frame in a sliding manner through the ball core positioning mechanism;

and the polishing mechanism is arranged on the second moving component and comprises a polishing cloth wheel, and the polishing cloth wheel does circular motion along the surface of the PE ball core.

The invention constructs a system for automatically polishing the PE ball core. The ball core rotating mechanism clamps the PE ball core to be polished and can rotate the PE ball core. The ball core positioning mechanism is used for moving the two-degree-of-freedom motion mechanism and positioning the rotation center of the two-degree-of-freedom motion mechanism at the ball center position of the PE ball core. And a second motion component of the two-degree-of-freedom motion mechanism is connected with the polishing mechanism to drive the polishing mechanism to move in the radial direction and is used for adjusting the contact distance between a polishing cloth wheel of the polishing mechanism and the PE ball core so as to control the polishing cloth wheel to apply constant radial pressure to the PE ball core. The first moving assembly moves circularly, and the second moving assembly drives the polishing mechanism to move circularly together, so that the polishing cloth wheel of the polishing mechanism can move in a circular arc manner along the surface of the PE ball core, and the PE ball core is polished. The system can automatically finish polishing the PE ball core, is simple to operate, and has lower requirements on the operating experience and the technical level of operators. The system can be adjusted through a two-degree-of-freedom motion mechanism, is suitable for polishing PE ball cores with different specifications and with the outer diameter of 100mm-315mm, which are commonly used in the industry of natural gas PE valves, and has strong applicability.

As a preferred scheme, the supporting frame comprises a plurality of upright posts and a cross beam connected between the top ends of the upright posts, the ball core rotating mechanism is arranged in the supporting frame, and the two-degree-of-freedom movement mechanism is positioned at the upper part of the ball core rotating mechanism and is arranged on the cross beam through the ball core positioning mechanism. This scheme adopts braced frame to install fixedly to the system, and braced frame passes through stand and crossbeam and constitutes square frame jointly. The ball core rotating mechanism is arranged in the supporting frame, the two-degree-of-freedom moving mechanism is arranged on the upper portion of the supporting frame and located on the upper portion of the ball core rotating mechanism, and the polishing mechanism extends into the supporting frame to polish the PE ball core.

As a preferred scheme, the first motion assembly comprises a support plate and an arc guide rail connected to the support plate, a swing arm is rotatably connected to the position, located at the circle center of the arc guide rail, of the support plate, the front end of the swing arm is connected with a guide rail trolley driven by a first motor, and the guide rail trolley is connected to the arc guide rail in a sliding mode. The arc guide rail of the first movement assembly is semicircular, and the semicircular arc guide rail can polish the surface of the PE ball core within 180 degrees. The circular arc guide rail is arranged on one side of the supporting plate, two ends of the circular arc guide rail are respectively fixed on the side face of the supporting plate, the circular position of the circular arc guide rail is located on the supporting plate, and a semicircular space is formed between the supporting plate and the circular arc guide rail so as to be used for setting and moving the polishing mechanism. Swing arm one end is rotated and is connected in the backup pad circular arc guide rail centre of a circle department, and the other end is connected with the guide rail dolly, and guide rail dolly sliding connection is on circular arc guide rail, and the swing arm can drive the guide rail dolly like this and carry out circular motion on circular arc guide rail.

As a preferred scheme, the guide rail trolley comprises a base and at least one pair of pulleys, the surfaces of the pulleys are arranged oppositely, a rotating shaft is arranged at the center of each pulley and fixed at the bottom of the base, the arc guide rail is clamped between the pair of pulleys, the first motor is arranged on the base, a driving gear linked with the first motor is arranged at the bottom of the base, a rack is arranged on the side surface of the arc guide rail, and the driving gear is meshed with the rack. The guide rail dolly instruction includes a pair of pulley in this scheme, generally adopts two pairs of pulleys, and the pulley adopts the setting of keeping flat, then installs on the base bottom through the pivot, and the pulley is two rows of correspondences and sets up, forms the space of installation circular arc guide rail between two rows of pulleys, and the circular arc guide rail centre gripping is between two rows of pulleys during the installation. This circular arc guide rail is T shape structure, is provided with the draw-in groove on the wheel face of pulley, and when the pulley was connected with the circular arc guide rail, the draw-in groove of pulley and the circular arc guide rail upper portion edge block of T shape for the pulley combines inseparabler with the circular arc guide rail, prevents that the pulley from breaking away from the guide rail, and plays the guide effect, makes the pulley slide more smoothly. The rack is specifically arranged on the side face of the lower part of the T-shaped arc guide rail, the rotating shaft of the first motor penetrates through the base, the bottom of the base is connected with the driving gear, the driving gear is meshed with the rack, and the first motor drives the driving gear to rotate, so that the guide rail trolley moves on the arc guide rail.

As a preferred scheme, the second motion assembly comprises a radial guide rail, a radial lead screw and a sliding block, the radial lead screw is fixedly arranged on the swing arm in a rotating mode, one end of the radial lead screw is connected with a second motor for driving the radial lead screw to rotate, the radial guide rail comprises a pair of radial lead screws which are respectively arranged on two sides of the radial lead screw, the sliding block is slidably arranged on the radial guide rail, a threaded sleeve is arranged at the bottom of the sliding block and in threaded connection with the radial lead screw, and the polishing mechanism is fixed on the sliding block. The fixed axis of radial lead screw rotates in this scheme and installs in the swing arm, and specific one that is located the backup pad in the swing arm is served and is provided with first fixed plate, is located one of guide rail dolly in the swing arm and serves and be provided with the second fixed plate, and radial silk axle one end is passed through the bearing and is installed on first fixed plate, and the second fixed plate is passed to the radial silk axle other end, is connected with second motor shaft, and radial silk axle also passes through the bearing and connects on the second fixed plate. Under the drive of the second motor, the radial screw shaft rotates in situ, and the slide block moves back and forth on the radial guide rail under the rotation of the screw thread of the radial screw shaft to drive the polishing mechanism to move radially.

As a preferred scheme, the ball core positioning mechanism comprises a first long slide rail, a long lead screw and a second long slide rail, the first long slide rail and the long lead screw are respectively arranged on two sides of a supporting frame, a first long slide rail sliding block is connected to the first long slide rail in a sliding manner, a long lead screw fixed shaft is installed on the supporting frame, one end of the long lead screw is connected with a third motor for driving the long lead screw to rotate, the second long slide rail comprises a pair of second long slide rails which are respectively arranged on two sides of the second long slide rail, a second long slide rail sliding block is connected to the second long slide rail in a sliding manner, a threaded sleeve is arranged at the bottom of the second long slide rail sliding block and is in threaded connection with the long lead screw, and the two-degree-of-freedom movement mechanism is. In the scheme, the ball core positioning mechanism is used for moving the rotation center of the two-degree-of-freedom motion mechanism to the linear position of the ball center of the PE ball core. The two-degree-of-freedom motion mechanism is fixed on a first long slide rail slide block and a second long slide rail slide block which are positioned on two sides of the supporting frame, and the two-degree-of-freedom motion mechanism is arranged at the upper part of the ball core rotating mechanism in a high-altitude mode. The third motor drives the filament shaft to rotate in a fixed shaft mode, the filament shaft rotates to drive the second long slide rail slide block in threaded connection with the filament shaft to slide on the second long slide rail, so that the two-degree-of-freedom motion mechanism is driven to move back and forth, and the position is adjusted until the center of a circle of a swing arm of the two-degree-of-freedom motion mechanism rotates to be on the straight line where the center of a circle of the PE ball core is located.

As a preferred scheme, polishing mechanism includes the fixed bolster, is provided with the card concave on fixed bolster upper portion, and the concave upper end of card is provided with the buckle, the concave cover of card is outside the second motion subassembly from bottom to top, and the buckle is fixed on the slider, is provided with the polishing motor in the fixed bolster, and the polishing motor pivot is worn out the fixed bolster lower extreme and is connected with the polishing cloth wheel, still is provided with torque sensor in the polishing motor pivot, and the system includes the controller, and torque sensor is connected to the controller. Polishing mechanism hangs and puts on the second motion subassembly in this scheme, and the fixed bolster is long columnar structure, and fixed bolster upper portion is that the card of U-shaped is concave, during the installation, will block concavely by lower supreme cover outside the second motion subassembly, by lower supreme cover swing arm and swing arm on the second motion subassembly promptly, fix the buckle on the slider, the buckle is connected with the upper end of the concave both sides of card, hangs the fixed bolster whole on the slider like this, blocks concavely and the swing arm contactless. The upper surface of the sliding block is provided with a limiting groove, the lower surface of the pinch plate is provided with a corresponding limiting block, and the limiting block is clamped into the limiting groove to be fixed during installation, so that the buckle is more stable. The torque sensor is used for collecting a torque value of the motor rotating shaft and sending the torque value to the controller. The polishing cloth wheel is arranged on the lower portion of the fixed support, a third motor rotating shaft penetrates through the fixed support to be connected with the polishing cloth wheel, the polishing cloth wheel is horizontally arranged, and the polishing cloth wheel is driven by the third motor to rotate in the horizontal plane. The installation height of the polishing cloth wheel is adjusted in advance, so that the plane where the polishing cloth wheel is located is superposed with the spherical center of the PE spherical core. The constancy of the radial pressure applied to the PE ball core by the polishing cloth wheel in the polishing process is the key for ensuring the polishing precision of the PE ball core. The polishing radial pressure is determined by the contact distance between the polishing cloth wheel and the PE ball core, and the smaller the distance between the polishing cloth wheel and the PE ball core, the larger the polishing radial pressure. The polishing precision is required to be accurately controlled, the distance between the polishing cloth wheel and the PE ball core needs to be adjusted according to the pressure between the polishing cloth wheel and the PE ball core, in practical application, the installation of a contact pressure sensor between the polishing cloth wheel (made of soft materials) and the PE ball core (made of hard materials) is difficult and complicated, the fact that a direct proportional relation exists between polishing torque and polishing pressure is considered, the polishing pressure is larger, the polishing pressure means that the polishing cloth wheel and the PE ball core are pressed more tightly, the torque received by the polishing cloth wheel is larger, the polishing torque received by the polishing cloth wheel is detected by adopting a torque sensor in the scheme, the direct detection of the polishing pressure is replaced, the installation operation is simple and convenient, and meanwhile, the control on the polishing precision is not.

Preferably, the ball core rotating mechanism comprises a base, wherein a support claw rotating along a horizontal shaft is arranged on the base, and the support claw is inserted into the through hole of the PE ball core and is supported and fixed. Prop the jack catch that the claw struts or contracts through the rotation among the prior art in this scheme, prop the whole ability of claw and rotate under motor control, this prop the claw and set to rotate along horizontal axial, be provided with the through-hole on the PE ball core, insert the through-hole with the jack catch during installation, prop open the support claw through the rotation, it is fixed to make to prop the claw and support in the through-hole formation, drive PE ball core around horizontal axis rotary motion through the rotation support claw during polishing operation, the polishing cloth wheel is circular motion around PE ball core under the motion of second motion subassembly, rotary motion place plane and circular motion place plane mutually perpendicular. The ball core rotating mechanism can be replaced by a common lathe, and the support claws can clamp the PE ball core by using a grabbing disc of the common lathe.

As a preferred scheme, still include the dust and retrieve the mechanism, the dust is retrieved the mechanism and is installed at the opposite side of the relative PE ball core of polishing cloth wheel, and the dust is retrieved the mechanism and is included the kuppe, kuppe both ends opening, and kuppe one end opening is provided with the suction fan towards polishing cloth wheel on the other port of kuppe, still is provided with the filter screen in the kuppe. Because a large amount of dust can be generated in the polishing process, the environment pollution is caused, and the physical health of the operators is threatened, the dust can be recovered by adopting the dust recovery mechanism, the environment pollution is reduced, and the physical health of the operators is threatened. An opening at one end of the air guide sleeve is aligned with the polishing cloth wheel, and under the action of the suction fan, dust is sucked into the air guide sleeve and is adhered to the filter screen.

A PE ball core automatic polishing control method based on torque control comprises the following steps:

s1, clamping a ball core, wherein a PE ball core is clamped on a ball core rotating mechanism;

s2, positioning the ball core, controlling the ball core positioning mechanism to move the two-degree-of-freedom motion mechanism until the circle center of the arc guide rail of the two-degree-of-freedom motion mechanism is completely overlapped with the circle center of the PE ball core; the ball core is positioned to provide a motion reference for the two-degree-of-freedom motion mechanism. The circle center of the circular arc guide rail of the two-degree-of-freedom motion mechanism is moved to a preset diameter specification position by controlling the rotating long screw rod, namely, the circle center of the circular arc guide rail is roughly adjusted to be positioned on the ball core. The invention can adopt an image positioning method, a binocular camera is arranged at the lower part of the circle center of the circular arc guide rail and is used for collecting images below the circle center of the circular arc guide rail, the system comprises a controller, the binocular camera is connected with the controller and sends shot images to the controller in real time, the microprocessor positions the circle center position of the circular arc guide rail and the circle center position of the ball core according to the images, the controller controls the third motor to drive the two-freedom-degree motion mechanism to move slowly until the circle center of the circular arc guide rail and the circle center of the ball core are completely coincided and positioned, the controller judges that the circle center of the circular arc guide rail and the circle center of the ball core are completely coincided.

S3, setting parameters, namely presetting the circular motion speed, the polishing reciprocating times and the torsion control value of the second motion assembly in the system;

s4, polishing the ball core, and controlling a first motor to move a polishing cloth wheel to the outer edge point of the PE ball core along an arc guide rail; controlling a second motor to move the polishing cloth wheel to the position with the largest diameter; starting a polishing motor to control a polishing cloth wheel to rotate, and starting a ball core rotating mechanism to drive a PE ball core to rotate; controlling a second motor to enable the polishing cloth wheel to gradually approach the outer edge point of the PE ball core until a signal detected by the torque sensor reaches a set torque control value; controlling a first motor to drive a polishing cloth wheel to do circular reciprocating motion; in the scheme, the polishing cloth wheel moves to the outer edge point of the PE ball core along the arc guide rail, namely, the polishing cloth wheel rotates to the position in contact with the outer edge point along the PE ball core, and the outer edge point is a set initial position. The maximum diameter position is a critical state or a non-contact state of the polishing cloth wheel in contact with the PE ball core outer aid point by adjusting the position of the polishing cloth wheel in a radial motion mode, and the maximum diameter position can be set according to requirements.

S5, quitting reset, controlling a second motor to move the polishing cloth wheel to the position with the maximum diameter after finishing the preset polishing reciprocating times, stopping the polishing motor, and waiting for a next polishing processing control command. The invention needs to replace the position of the PE ball core to respectively polish the two half surfaces of the PE ball core. After the system is reset, the PE core is replaced, and the steps S4 and S5 are repeated for the next polishing process. The core positioning can be carried out without repetition for the PE core with the same specification.

As a preferable scheme, the process of step S4 further includes a polishing torque control step:

s401, a torque sensor collects polishing torque information of a polishing motor in real time and sends the information to a controller;

s402, the controller compares the collected torque information with a set torque control value and judges whether the torque is larger than or smaller than the torque control value;

s403, when the torque force is judged to be larger than the torque force control value, controlling a second motor to increase the distance between the polishing cloth wheel and the surface of the ball core, and returning to the step S402;

when the torque is smaller than the torque control value, the second motor is controlled to reduce the distance between the polishing cloth wheel and the surface of the ball core, and the step S402 is returned to.

The controller controls the first motor to drive the polishing cloth wheel seat to move circularly, and if the roundness error of the PE ball core is zero, namely the PE ball core is a strict sphere, the distance between the polishing cloth wheel and the PE ball core is kept constant, so that the polishing pressure is constant. And in the actual polishing process, the roundness error of the PE ball core cannot be zero, so that the polishing pressure is changed in real time in the actual polishing process, and the control unit controls the second motor to adjust the distance between the polishing cloth wheel and the PE ball core according to the change of the received torque value so as to keep the torque value within a proper range.

As a preferable scheme, the process of step S4 further includes a fault control step:

s411, a torque sensor collects polishing torque information of a polishing motor in real time and sends the information to a controller;

s412, presetting a time limit t and a first torque threshold N1 for a torque abrupt increase fault and a second torque threshold N2 for a mechanical jamming fault;

s413, the controller compares the collected current torque information with a set torque control value, judges whether the torque is greater than the torque control value, if so, enters the following step, and if not, ends the step;

s414, judging whether the difference value between the current torque force and the torque force before the moment t is greater than a first torque force threshold value N1, if so, controlling a second motor to move the polishing cloth wheel away from the surface of the ball core, and automatically stopping the system; if not, finishing the step;

judging whether the current torque force is greater than a second torque force threshold value N2, if so, controlling a second motor to move the polishing cloth wheel away from the surface of the ball core, and automatically stopping the system; if not, the step is ended.

When the faults of abrupt increase of the torsion, mechanical locking and the like occur, the controller controls the second motor to drive the polishing cloth wheel to move away along the diameter direction, so that accidents in the motion process are prevented. In order to ensure safety, an emergency stop manual key can be arranged.

Therefore, the invention has the advantages that:

1. the polishing device can automatically finish polishing the PE ball core, is simple to operate, and has lower requirements on the operating experience and the technical level of operators.

2. The polishing device is adjusted by a two-degree-of-freedom motion mechanism, is suitable for polishing PE ball cores with different specifications and with the outer diameter of 100-315 mm, which are commonly used in the industry of natural gas PE valves, and has strong applicability.

3. The polishing torque received by the polishing cloth wheel is detected by the torque sensor to replace direct detection of polishing pressure, so that the installation and operation are simple and convenient, and the control on the polishing precision is not influenced.

4. The dust recovery mechanism can recover dust, effectively improves the air quality and the air environment of a PE ball core polishing process place, and reduces the threat to the health of operators.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention;

FIG. 2 is a schematic structural diagram of a two-degree-of-freedom motion mechanism according to the present invention;

FIG. 3 is a schematic view of a core positioning mechanism according to the present invention;

FIG. 4 is a schematic view of a combination of the circular arc guide rail and the guide rail trolley according to the present invention;

FIG. 5 is a schematic view of a polishing mechanism according to the present invention;

FIG. 6 is a schematic view showing a structure of a dust recovery mechanism according to the present invention;

FIG. 7 is a schematic view of a configuration of the present invention in which the buffing wheel contacts the PE core;

FIG. 8 is a schematic diagram of an electrical control arrangement of the present invention;

FIG. 9 is a schematic flow chart of a control method of the present invention;

FIG. 10 is a schematic flow chart of polishing torque control according to the present invention;

fig. 11 is a schematic flow chart of the fault control in the present invention.

The method comprises the following steps of 1, a support plate 2, an arc guide rail 3, a swing arm 4, a first motor 5, a guide rail trolley 6, a base 7, a pulley 8, a radial guide rail 9, a radial screw rod 10, a sliding block 11, a second motor 12, a first long sliding rail 13, a long screw rod 14, a second long sliding rail 15, a first long sliding rail sliding block 16, a second long sliding rail sliding block 17, a third motor 18, a fixed support 19, a clamping groove 20, a buckle plate 21, a polishing motor 22, a polishing cloth wheel 23, a torque sensor 24, a support frame 25, an upright post 26, a cross beam 27, a machine base 28, a PE ball core 29, a flow guide cover 30, an air suction fan 31, a filter screen 32, a controller 33 and a touch.

Detailed Description

The technical scheme of the invention is further specifically described by the following embodiments and the accompanying drawings.

Example (b):

the embodiment provides a PE (polyethylene) ball core automatic polishing system based on torque control, as shown in fig. 1, the system comprises a supporting frame 24, a ball core rotating mechanism for clamping a PE ball core 28 is arranged in the supporting frame, a two-degree-of-freedom motion mechanism is arranged on the upper portion of the supporting frame, the two-degree-of-freedom motion mechanism comprises a first motion component and a second motion component, the first motion component is in circular motion, the second motion component is in radial motion, the second motion component is arranged on the first motion component, the first motion component is arranged on the supporting frame in a sliding mode through a ball core positioning mechanism, a polishing mechanism is further arranged on the second motion component, the polishing mechanism is arranged in the supporting frame in a vertical mode, the polishing mechanism comprises a polishing cloth wheel, and the polishing cloth wheel is. And a dust recovery mechanism is also arranged on one side of the polishing cloth wheel.

The support frame is used for mounting the components. The ball core rotating mechanism clamps the PE ball core to be polished and can rotate the PE ball core. The ball core positioning mechanism is used for moving the two-degree-of-freedom motion mechanism and positioning the rotation center of the two-degree-of-freedom motion mechanism at the ball center position of the PE ball core. And a second motion component of the two-degree-of-freedom motion mechanism is connected with the polishing mechanism to drive the polishing mechanism to move in the radial direction and is used for adjusting the contact distance between a polishing cloth wheel of the polishing mechanism and the PE ball core so as to control the polishing cloth wheel to apply constant radial pressure to the PE ball core. The first moving assembly moves circularly, the polishing mechanism is driven by the first moving assembly to move circularly together, and the polishing cloth wheel moves in an arc shape along the surface of the PE ball core to polish the PE ball core. The system can automatically finish polishing the PE ball core, is simple to operate, and has lower requirements on the operating experience and the technical level of operators. The system can be adjusted through a two-degree-of-freedom motion mechanism, is suitable for polishing PE ball cores with different specifications and with the outer diameter of 100mm-315mm, which are commonly used in the industry of natural gas PE valves, and has strong applicability.

The support frame 24 comprises four uprights 25 and cross-members 26 connected between the tops of the uprights to form a directional frame structure. The ball core rotating mechanism is arranged in the supporting frame, and the two-degree-of-freedom movement mechanism is positioned at the upper part of the ball core rotating mechanism and is arranged on the cross beams at two sides through the ball core positioning mechanism.

As shown in figure 2, the first moving assembly comprises a support plate 1 and an arc guide rail 2 connected to the support plate, a swing arm 3 is rotatably connected to the position, located at the circle center of the arc guide rail, of the support plate, the front end of the swing arm is connected with a guide rail trolley 5 driven by a first motor 4, and the guide rail trolley is slidably connected to the arc guide rail. The circular arc guide rail is semi-circular in this embodiment, can realize 180 degrees rotations, and the circular arc guide rail both ends are connected in backup pad one side, form the space that sets up polishing mechanism between circular arc guide rail and the backup pad. In order to ensure that the two-degree-of-freedom motion mechanism is installed more stably, a connecting plate is arranged between the outer side of the arc guide rail and the supporting plate for fixing. As shown in fig. 4, the rail trolley 5 includes a base 6 and two pairs of pulleys 7, the two pairs of pulleys are arranged in two rows, the pulleys are horizontally placed, the pulley surfaces of the two rows of pulleys are opposite, a rotating shaft is arranged at the center of the pulley, the rotating shaft is fixed at the bottom of the base, and the arc guide rail is clamped between the two rows of pulleys during installation. The arc guide rail is of a T-shaped structure, a clamping groove is correspondingly arranged on the wheel surface of the pulley, and the edge of the upper part of the arc guide rail is clamped in the clamping groove of the pulley during connection. The first motor 4 is installed on the base, a rotating shaft of the first motor penetrates through the base, the bottom of the base is connected with a driving gear, a rack is arranged on the side face of the lower portion of the arc sliding rail, and the driving gear is meshed with the rack. One end of the swing arm is fixed on the base.

The second motion assembly comprises a radial guide rail 8, a radial lead screw 9 and a slide 10. Radial lead screw dead axle rotates to be installed on swing arm 3, is provided with first fixed plate in the swing arm is located one end of backup pad, is located one end of guide rail dolly in the swing arm and is provided with the second fixed plate, and radial silk axle one end is installed on first fixed plate through the bearing, and its pivoted second motor 12 of drive is connected to the radial silk axle other end through the second fixed plate, and radial silk axle also is connected through the bearing with the second fixed plate. The radial guide rail comprises a pair of radial guide rails which are respectively arranged on two sides of the radial screw rod and fixed between the first fixing plate and the second fixing plate. The sliding block is slidably mounted on the radial guide rail, a threaded sleeve is arranged at the bottom of the sliding block and is in threaded connection with the radial lead screw, and the polishing mechanism is fixed on the sliding block.

As shown in fig. 3, the ball core positioning mechanism includes a first long slide rail 12, a long filament rod 13 and a second long slide rail 14, the first long slide rail and the long filament rod are respectively arranged on the cross beams at two sides of the supporting frame, a first long slide rail slider 15 is slidably connected on the first long slide rail, the long filament rod is fixed on the cross beams, a third fixing plate and a fourth fixing plate are respectively arranged at two ends of the cross beams, one end of the long filament rod is connected on the third fixing plate through a bearing, the other end of the long filament rod rushes through the fourth fixing plate to connect and drive a third motor 17 for rotating the long filament rod, and the long filament rod is connected with the fourth fixing plate through a bearing. The second field slide rail comprises a pair of second long slide rails, the second long slide rails are respectively arranged on two sides of the second long slide rail and fixed between the third fixing plate and the fourth fixing plate, a second long slide rail sliding block 16 is connected to the second long slide rail in a sliding mode, and a threaded sleeve is arranged at the bottom of the second long slide rail sliding block and in threaded connection with the long screw rod. Two sides of a connecting plate of the two-degree-of-freedom motion mechanism are respectively connected to the first long slide rail slide block and the second long slide rail slide block, and the two-degree-of-freedom motion mechanism is erected on the supporting frame.

As shown in FIG. 5, the polishing mechanism comprises a fixed bracket 18, a clamping groove 19 is arranged at the upper part of the fixed bracket, and a buckle plate 20 is arranged at the upper end of the clamping groove. When the polishing mechanism is installed, the buckle plate is fixed on the sliding block, the clamping groove is sleeved outside the second moving assembly from bottom to top, and the buckle plate and the clamping groove are fixed, so that the polishing mechanism is integrally hung on the second moving assembly and moves along with the sliding block. A polishing motor 21 is arranged in the fixed support, a rotating shaft of the polishing motor penetrates out of the lower end of the fixed support to be connected with a polishing cloth wheel 22, and the polishing cloth wheel is horizontally arranged and rotates in the horizontal plane under the driving of the polishing motor. A notch is formed in one side, facing the supporting plate, of the polishing support clamping concave, the shape of the notch is matched with that of the supporting plate, and when the fixing support moves to the position where the second moving assembly leans against the supporting plate portion, the notch can be sleeved into the supporting plate to prevent the fixing support from being blocked by the supporting plate.

And a torque sensor is also arranged on the rotating shaft of the polishing motor, the system comprises a controller, and the torque sensor is connected to the controller. The torque sensor is used for collecting a torque value of the motor rotating shaft and sending the torque value to the controller. Because the polishing precision is related to the constancy of the radial pressure applied to the PE ball core by the polishing cloth wheel in the polishing process, the distance between the polishing cloth wheel and the PE ball core needs to be adjusted according to the pressure between the polishing cloth wheel and the PE ball core in order to accurately control the polishing precision, in practical application, a contact pressure sensor between the polishing cloth wheel (made of soft materials) and the PE ball core (made of hard materials) is difficult and complicated to mount, and the polishing torque and the polishing pressure are in direct proportion. The controller is also connected with the first motor, the second motor, the third motor and the polishing motor to control the motors to work. The controller compares the torque value sent by the torque sensor with a set torque control value, and controls the second motor to adjust the distance between the polishing cloth wheel and the PE ball core according to the comparison structure so as to keep the torque value within a proper range, achieve the constancy of radial pressure and accurately control the polishing precision.

The core rotating mechanism comprises a base 27, and a support claw which rotates along a horizontal shaft is arranged on the base and is inserted into a through hole of the PE core and is supported and fixed. The support claw is a claw which is opened or contracted through rotation, the whole support claw can rotate under the control of a motor, the support claw is arranged to rotate along the horizontal axial direction, the ball core rotating mechanism can be replaced by a common lathe, and the support claw uses a gripping disk of the common lathe to grip the PE ball core. The PE ball core is provided with a through hole, the clamping jaw is inserted into the through hole during installation, and the supporting jaw is opened through rotation, so that the supporting jaw is supported in the through hole to form fixation. As shown in fig. 7, during polishing operation, the PE core is driven to rotate around the horizontal axis by the rotation of the support claw, and the polishing cloth wheel is driven by the first motion assembly to make circular motion around the PE core, and the plane of the rotation is perpendicular to the plane of the circular motion. Ensure that every part of the PE core cannot be polished.

As shown in fig. 6, the dust recovery mechanism is installed on the other side of the polishing cloth wheel 22 opposite to the PE core. The dust recovery mechanism comprises a flow guide cover 29, two ends of the flow guide cover are opened, one end of the flow guide cover is opened towards the polishing cloth wheel and is close to the PE ball core, and the flow guide cover, the polishing cloth wheel and the PE ball core can be arranged in a row. The other end of the air guide sleeve is provided with an air suction fan 30, and a filter screen 31 is also arranged in the air guide sleeve. The opening of the air guide sleeve is aligned with the polishing cloth wheel, and under the action of the suction fan, dust is sucked into the air guide sleeve and is adhered to the filter screen.

The electric appliance control structure of the embodiment is as shown in fig. 8, the first motor, the second motor, the third motor and the polishing motor are respectively connected to the controller and controlled by the controller, the torque sensor is arranged on the polishing motor, the torque of the polishing motor is collected, and the torque sensor is connected with the controller. And the system also comprises a touch screen 33 used for carrying out interactive operation, and the touch screen is connected with the controller. The electrical parameters of each part are:

a controller: 64-point host, 32DI/32DO (relay/250 VAac/24 Vdc/2A), with 6-way analog quantity expansion module;

a torque sensor: a high-speed dynamic torque sensor outputs 4-20mA at +/-12V and 0-5 Nm;

polishing the motor: a three-phase asynchronous alternating current motor, 380V, 750kW, 50Hz and 1500 rpm;

first, second, third motors: the alternating current servo motor is driven by a servo driver, is 220V and 400W and comprises a speed encoder;

a touch screen: 7 cun human-machine interface, DOP-107 BV.

A PE ball core automatic polishing control method based on torque control is shown in FIG. 9, and comprises the following steps:

s2, positioning the ball core, controlling the ball core positioning mechanism to move the two-degree-of-freedom motion mechanism until the circle center of the arc guide rail of the two-degree-of-freedom motion mechanism is completely overlapped with the circle center of the PE ball core;

the ball core is positioned to provide a motion reference for the two-degree-of-freedom motion mechanism. The circle center of the circular arc guide rail of the two-degree-of-freedom motion mechanism is moved to a preset diameter specification position by controlling the rotating long screw rod, namely, the circle center of the circular arc guide rail is roughly adjusted to be positioned on the ball core. The system comprises a controller, the binocular camera is connected with the controller and sends shot images to the controller in real time, the microprocessor positions the circle center position of the circular arc guide rail and the circle center position of the ball core according to the images, the controller controls the third motor to drive the two-degree-of-freedom motion mechanism to move slowly until the circle center of the circular arc guide rail and the circle center of the ball core are completely coincided and positioned, the controller judges that the circle center of the circular arc guide rail and the circle center of the ball core are completely coincided, the third motor is stopped, and sound and light prompts are sent. In addition, a laser scanning positioning method can also be adopted, a laser distance sensor is arranged at the lower part of the circle center of the arc guide rail, the laser distance sensor emits laser downwards, and the laser distance sensor is connected to the controller. The laser distance sensor is driven to do horizontal scanning movement by controlling the movement of the ball core positioning mechanism, the laser distance sensor detects the distance value between the surface of the PE ball core and the laser distance sensor in real time during the movement, data are sent to the controller after the scanning is finished, the controller compares the distance value to obtain the minimum distance value point, then the third motor is controlled to move the two-degree-of-freedom movement mechanism to the point position with the minimum distance between the laser distance sensor and the surface of the PE ball core, and the ball core positioning of the PE ball core is completed. For polishing the PE ball cores of the same specification, the first positioning is generally needed, and the subsequent batch polishing of the cylinder specification does not need to be positioned again.

s4, polishing the ball core,

controlling a first motor to move the polishing cloth wheel to the outer edge point of the PE ball core along the arc guide rail;

controlling a second motor to move the polishing cloth wheel to the position with the largest diameter;

starting a polishing motor to control a polishing cloth wheel to rotate, and starting a ball core rotating mechanism to drive a PE ball core to rotate;

controlling a second motor to enable the polishing cloth wheel to gradually approach the outer edge point of the PE ball core until a signal detected by the torque sensor reaches a set torque control value;

controlling a first motor to drive a polishing cloth wheel to do circular reciprocating motion;

in the scheme, the polishing cloth wheel moves to the outer edge point of the PE ball core along the arc guide rail, namely, the polishing cloth wheel rotates to the position in contact with the outer edge point along the PE ball core, and the outer edge point is a set initial position. The maximum diameter position is a critical state or a non-contact state of the polishing cloth wheel in contact with the PE ball core outer aid point by adjusting the position of the polishing cloth wheel in a radial motion mode, and the maximum diameter position can be set according to requirements.

In the polishing process of step S4, as shown in fig. 10, a polishing torque control step is further included:

As shown in fig. 11, the process of step S4 further includes a failure control step:

The torque sensor collects polishing torque information of the polishing motor in real time and sends the information to the controller; the controller compares the acquired torque information with a set torque control value, controls the second motor to drive the polishing cloth wheel to move according to the comparison result, namely, the distance between the polishing cloth wheel and the surface of the ball core is increased to reduce the polishing torque when the torque becomes larger, and the distance between the polishing cloth wheel and the surface of the ball core is reduced to increase the polishing pressure when the torque becomes smaller. So that the detected torque is kept within a proper range, ensuring constant torque control. If the torsion suddenly increases, the machine is stuck and other faults occur, the controller controls the second motor to drive the polishing cloth wheel to move away along the diameter direction. In addition, in order to ensure safety, an emergency stop button is further arranged and is connected with the controller.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although the terms support plate, circular arc guide, swing arm, first motor, etc. are used more herein, the possibility of using other terms is not excluded. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.

Claims

1. The utility model provides a PE ball core automatic polishing system based on torque control which characterized in that: comprises the steps of (a) preparing a mixture of a plurality of raw materials,

the support frame (24), there is core rotary mechanism to grasp PE core (28) in the support frame, the upper portion of the support frame has kinematic mechanisms of two degrees of freedom;

and the polishing mechanism is arranged on the second moving component and comprises a polishing cloth wheel (22), and the polishing cloth wheel performs circular motion along the surface of the PE ball core.

2. The PE ball core automatic polishing system based on torque control as claimed in claim 1, wherein the supporting frame (24) comprises a plurality of upright posts (25) and a cross beam (26) connected between the top ends of the upright posts, the ball core rotating mechanism is arranged in the supporting frame, the two-degree-of-freedom motion mechanism is positioned at the upper part of the ball core rotating mechanism and is arranged on the cross beam through the ball core positioning mechanism; the ball core rotating mechanism comprises a base (27), wherein a supporting claw which rotates along a horizontal shaft is arranged on the base, and the supporting claw is inserted into a through hole of the PE ball core and is supported and fixed.

3. The PE ball core automatic polishing system based on torque control as claimed in claim 1 or 2, wherein the first motion assembly comprises a support plate (1) and a circular arc guide rail (2) connected to the support plate, a swing arm (3) is rotatably connected to the support plate at the center of the circular arc guide rail, the front end of the swing arm is connected with a guide rail trolley (5) driven by a first motor (4), the guide rail trolley is slidably connected to the circular arc guide rail, the guide rail trolley (5) comprises a base (6) and at least one pair of pulleys (7), the pulley surfaces are oppositely arranged, a rotating shaft is arranged at the center of the pulley and fixed at the bottom of the base, the circular arc guide rail is clamped between the pair of pulleys, the first motor is arranged on the base, a driving gear linked with the first motor is arranged at the bottom of the base, and a rack is arranged on the side surface of the, the driving gear is meshed with the rack.

4. The PE ball core automatic polishing system based on the torque control as claimed in claim 3, wherein the second motion assembly comprises a radial guide rail (8), a radial lead screw (9) and a slide block (10), the radial lead screw is fixedly and rotatably mounted on the swing arm (3), one end of the radial lead screw is connected with a second motor (12) for driving the radial lead screw to rotate, the radial guide rail comprises a pair of radial guide rails which are respectively arranged at two sides of the radial lead screw, the slide block is slidably mounted on the radial guide rail, a threaded sleeve is arranged at the bottom of the slide block and is in threaded connection with the radial lead screw, and the polishing mechanism is fixed on the slide block.

5. The automatic PE ball core polishing system based on the torque control as claimed in claim 1 or 2, wherein the ball core positioning mechanism comprises a first long slide rail (12), a filament rod (13) and a second long slide rail (14), the first long slide rail and the filament rod are respectively arranged on two sides of the support frame, a first long slide rail slider (15) is slidably connected to the first long slide rail, the filament rod is fixedly mounted on the support frame, one end of the filament rod is connected with a third motor (17) for driving the filament rod to rotate, the second field slide rail comprises a pair of long slide rails, the pair of long slide rails are respectively arranged on two sides of the second long slide rail, a second long slide rail slider (16) is slidably connected to the second long slide rail, a threaded sleeve is arranged at the bottom of the second long slide rail slider and is in threaded connection with the filament rod, and a two-degree-of-freedom movement mechanism is mounted on the first long slide rail slider.

6. The PE ball core automatic polishing system based on torque control as claimed in claim 4, wherein the polishing mechanism comprises a fixed support (18), a clamping groove (19) is arranged at the upper part of the fixed support, a buckling plate (20) is arranged at the upper end of the clamping groove, the clamping groove is sleeved outside the second moving component from bottom to top, the buckling plate is fixed on the sliding block (10), a polishing motor (21) is arranged in the fixed support, a rotating shaft of the polishing motor penetrates out of the lower end of the fixed support to be connected with the polishing cloth wheel (22), a torque sensor is further arranged on the rotating shaft of the polishing motor, and the system comprises a controller, and the torque sensor is connected to the controller.

7. The automatic PE ball core polishing system based on the torque control as claimed in claim 1, further comprising a dust recycling mechanism, wherein the dust recycling mechanism is mounted on the other side of the polishing cloth wheel (22) opposite to the PE ball core, the dust recycling mechanism comprises a flow guide cover (29), two ends of the flow guide cover are open, one end of the flow guide cover is open and faces the polishing cloth wheel, an air suction fan (30) is arranged on the other end of the flow guide cover, and a filter screen (31) is further arranged in the flow guide cover.

8. A method for controlling automatic polishing of a PE core based on torque control, using the system of any one of claims 1-7, comprising the steps of:

s4, polishing the ball core, and controlling a first motor to move a polishing cloth wheel to the outer edge point of the PE ball core along an arc guide rail; controlling a second motor to move the polishing cloth wheel to the position with the largest diameter; starting a polishing motor to control a polishing cloth wheel to rotate, and starting a ball core rotating mechanism to drive a PE ball core to rotate; controlling a second motor to enable the polishing cloth wheel to gradually approach the outer edge point of the PE ball core until a signal detected by the torque sensor reaches a set torque control value; controlling a first motor to drive a polishing cloth wheel to do circular reciprocating motion;

s5, quitting reset, controlling a second motor to move the polishing cloth wheel to the position with the maximum diameter after finishing the preset polishing reciprocating times, stopping the polishing motor, and waiting for a next polishing processing control command.

9. The method as claimed in claim 8, wherein the step S4 further comprises a polishing torque control step:

10. The method of claim 9, wherein the step S4 further comprises a failure control step of: