CN2035815U - Electric-controlling hydraulic actuator with capacitance sensor - Google Patents

Abstract

The utility model discloses an electric-controlling hydraulic actuator with capacitance sensor. The oil in the cylinder body is pumped by a gear pump driven by the motor, and a piston and a tension bar are pushed to make reciprocating motion. The tension bar and an electrode with an insulating sleeve inserted in the hollow hole of the tension bar form a variable capacitor. The variable capacitor is arranged in a displacement feedback circuit, and the final output whose electric current is 4 to 20 milliamp as the indication of the position of the tension rod. The electric-controlling hydraulic actuator with a capacitance sensor is suitable for using in the coal separating plant, or the various valves driven by the coal separating plant and the straight stroke load. The electric-controlling hydraulic actuator with a capacitance sensor has the advantages of simple structure, small size and large output, and a complete linear relation is existed between the electric capacity of the variable-capacitance and the extension length of the tension rod.

Description

Electric-controlling hydraulic actuator with capacitance sensor

The invention belongs to hydraulic actuator, be applicable to that particularly coal preparation plant or ore dressing plant drive the open and close of various valves (as the valve that heavily is situated between, feed, discharge gate valve and bunker gate etc.), and the electrically controlled and hydraulically actuator that drives other straight journey load.It can be combined into control automatic valve far away with the plate valve, is executive component desirable in the automatic control system.

At present, the various valves in coal separation or the ore-dressing technique system, great majority are still realized opening or closing using handwheel to drive screw mandrel, and not only inconvenience but also require great effort particularly winter, because valve is not tight, was often freezed, and caused the parking accident, and influence is produced.In recent years, along with coal separation or the development of ore-dressing technique system automation, automatically controlled final controlling element is brought into use in some coal preparation plant or ore dressing plant.Disclose a kind of " control valve with DF-II type final controlling element " as " coal preparation technology " second phase in 1984, it is made up of automatically controlled pneumatic actuator and position feedback circuit.Wherein actuator comprises a cylinder body, and the band piston pulling is housed in cylinder body, and the overhanging end of pull bar is connected with load (spool); Pressurized air enters lower chamber and promotes piston and drive the bottom-up motion of pull bar; Otherwise pressurized air enters upper gas chamber and promotes piston and drive pull bar from up to down to move, and realizes the operation that opens or closes of valve.Nonmetal cylinder sleeve constitutes the displacement sensor transformer in above-mentioned pull bar, piston and the cylinder body, converts the mechanical displacement of pull bar to electrical signal, as the Displacement Feedback signal of draw rod positions indication and final controlling element.DF-II type final controlling element drives screw mandrel than handwheel, and to open or close valve easy to use, and switch is flexible, shortens to start or dead time, and is easy and simple to handle, greatly alleviates labor strength.But this final controlling element needs wind regime; Nonmetal cylinder sleeve is set in the cylinder body, makes complex structure, be difficult for sealing, volume is big, and is heavy; Not exclusively be linear relationship between displacement sensor transformer output voltage and the pull bar extension.

Task of the present invention provides a kind of electrically controlled and hydraulically final controlling element that has capacitance displacement sensor.This final controlling element is that reversing motor drags the reversible gear pump, pumps the fluid of final controlling element self, and the piston and the pull bar that promote in the cylinder body seesaw; The mechanical displacement of pull bar is to overlap the variable condenser that electrode constituted by the tape insulation that inserts in the pull bar hollow hole, and this variable condenser places the position feedback circuit, converts thereof into electrical signal, as draw rod positions indication and final controlling element Displacement Feedback signal.Owing to cancelled the nonmetal cylinder sleeve in the cylinder body and promoted the wind regime that piston pulling rod moves, actuator structure is greatly simplified, sealing easily, smaller volume, it is bigger to exert oneself; Has linear relationship completely between the Capacity of variable capacitance and the pull bar extension.

Describe structure of the present invention and mode of execution in detail below in conjunction with accompanying drawing.

Mechanical structure front view of the present invention shown in Figure 1.

Displacement Feedback circuit of the present invention shown in Figure 2.

As shown in Figure 1, have the electrically controlled and hydraulically final controlling element of capacitance displacement sensor, comprise a two-phase or three-phase reversing motor ［ 15 ］, the main shaft of this motor links to each other with the driving gear shaft of reversible gear pump ［ 11 ］ by coupling drive ［ 14 ］; One end of gear pump is communicated with liquid chamber ［ 17 ］ after the actuator by the oil pipe that moves ahead ［ 12 ］; The other end of gear pump is communicated with liquid chamber ［ 16 ］ before the actuator by back row oil pipe ［ 13 ］.Said actuator comprises cylinder body ［ 4 ］, connects firmly a protecgulum ［ 2 ］ at the front end of cylinder body, in order to the overhanging end of tie-strut ［ 1 ］; Pull bar ［ 1 ］ end that occupies in the cylinder body connects firmly a piston ［ 5 ］, and the front cavity of piston is preceding liquid chamber ［ 16 ］, and the rear portion is a back liquid chamber ［ 17 ］.Pull bar ［ 1 ］ is a metallic rod of band hollow hole.The rear end of cylinder body connects firmly a bonnet ［ 7 ］, and in order to the electrode ［ 6 ］ of supporting band insulating bush, the afterbody of this electrode is fixed a front end circuit plate ［ 9 ］; On the front end circuit plate, lay the front end circuit of Displacement Feedback circuit ［ 18 ］ as shown in Figure 2.Adopt V-shaped seal ring ［ 3 ］ sealing between the protecgulum of actuator, the overhanging end of pull bar and the cylinder body; Adopt O RunddichtringO ［ 8 ］ sealing between bonnet and the cylinder body.Previously described tape insulation cover electrode ［ 6 ］ inserts in pull bar ［ 1 ］ hollow hole, constitute a variable condenser, this variable condenser places among the Displacement Feedback circuit shown in Figure 2, promptly be equivalent to the Cx in the front end circuit ［ 18 ］, wherein a point is electrically connected with pull bar ［ 1 ］, and the b point is electrically connected with tape insulation cover electrode ［ 6 ］.

When the driving wheel of motor ［ 15 ］ driven gear pump ［ 11 ］ counterclockwise rotates, gear pump pumps to back liquid chamber ［ 17 ］ with the fluid of preceding liquid chamber ［ 16 ］ by the oil pipe that moves ahead ［ 12 ］, and piston ［ 5 ］ drives pull bar ［ 1 ］ and travels forward; Otherwise when motor drives gear pump driving wheel clockwise direction rotated, gear pump pumped to preceding liquid chamber with the fluid of back liquid chamber by back row oil pipe ［ 13 ］, and piston drives pull bar and moves backward.During the pull bar motion, the tape insulation cover electrode ［ 6 ］ that inserts in the pull bar hollow hole is motionless relatively, therefore along with pull bar travels forward, and the extension lengthening, pull bar and tape insulation cover electrode relative area reduce, and the Cx Capacity reduces; Otherwise pull bar moves backward, and pull bar and tape insulation cover electrode relative area increase, and the Cx Capacity increases.

Displacement Feedback circuit shown in Figure 2 is that pull bar machinery displacement conversion mentioned above is become electrical signal, in order to indication and the actuator position feedback signal as draw rod positions.It is made up of front end circuit ［ 18 ］ and amplification change-over circuit.

Front end circuit is to be the vibrator circuit of core and to be that the change-over circuit of core constitutes with BG2 by BG1.In the half cycle of bearing just down in the transformer secondary L2 appearance in vibrator circuit, capacitance C5, C4 and variable capacitance Cx penetrate amplification in the Voltage Series that the upper half charging is produced through triode BG2 base, produce signal code i _bAmplify output half-wave current i through BG2, obviously capacitor C x is big more, signal code i _bJust big, half-wave current i is also big.Because variable capacitance Cx is very little, disturb for preventing lead-in wire, the circuit board ［ 9 ］ of its front end circuit ［ 18 ］ is installed in the bonnet of actuator.

Half-wave current i produces pressure drop on the resistance R 9 of amplifying change-over circuit ［ 19 ］, be added on the normal phase input end 3 of amplifier F1, F1 output positive voltage is descended, by amplifier F2 its output negative voltage is reduced, amplifying through amplifier F3 reduces its output positive voltage again, make triode BG3 penetrate base current and increase, amplify, output current is increased through BG3 and BG4.Regulate potentiometer W1, when making actuator's pull bar ［ 1 ］ be in the extension maximum, F1 exports a suitable positive voltage, and F2 exports a suitable negative voltage, and F3 exports sufficiently high positive voltage, and making BG3 that one minimum signal electric current be arranged is 4 milliamperes; Regulate potentiometer W2, make actuator's pull bar by the extension maximum retraction during to the maximum opening position, the output signal electric current rises to 20 milliamperes by 4 milliamperes, Here it is adjusting as final controlling element draw rod positions indication and position feed back signal, this signal code has the [constant characteristic, can realize teletransmission.

Claims (4)

1, a kind of electrically controlled and hydraulically final controlling element, comprise motor [15], coupling drive [14], gear pump [11], actuator, Displacement Feedback circuit, it is characterized in that actuator's cylinder body [4] protecgulum [2] supports the metal pull bar [1] of movable belt hollow hole, insert tape insulation cover electrode [6] in the hollow hole of pull bar, electrode [6] is supported by the bonnet [7] of cylinder body.

2,, it is characterized in that metal pull bar ［ 1 ］, tape insulation cover electrode ［ 6 ］ are connected with the front end circuit ［ 18 ］ of Displacement Feedback circuit, form a variable condenser according to the described final controlling element of claim 1.

3,, it is characterized in that front end circuit plate ［ 9 ］ is installed in the afterbody of tape insulation cover electrode according to claim 1 or 2 described final controlling element.

4, according to the described final controlling element of claim 1, it is characterized in that an end of gear pump is communicated with liquid chamber ［ 17 ］ after the actuator by preceding execution oil pipe ［ 12 ］, the gear pump the other end is communicated with liquid chamber ［ 16 ］ before the actuator by back row oil pipe ［ 13 ］.