The numerical control electric constant torque wrench
Technical field
The utility model relates to a kind of constant torque wrench, relates in particular to a kind of numerical control electric constant torque wrench.
Background technology
General all wants just tightly tight eventually more earlier for the fastening of high-strength bolt, and per step needs that all strict torque demand is arranged.The first of big hexagonal high-strength bolt tightly and eventually tightly all must be used constant torque wrench.The electric torque spanner is by motor, and the force booster type spanner of the starlike gear train composition of shape.It has volume little, in light weight, tear that lock speed is fast, peak torque can reach 20000Nm open.Be to have the more selection of high-efficiency and economic than hydraulic spanner, can make a good job of the task of the loading and unloading of large diameter bolt nut, and it is the same with hydraulic spanner, be not with impact, and its tighten and dismounting speed faster than hydraulic spanner, can advance one one and promote efficient, price is then more economical than hydraulic spanner, has non-maintaining advantage.
Common electronic wrest fixing spanner can be divided into two kinds of current type and dynamic torque sensor formulas, and it is all by controller with tighten axle and form.The current type wrest fixing spanner is judged torque value according to the variation of current value in the motor rundown process, and when reaching predetermined torsion, motor quits work.And the dynamic torque sensor formula is sensor to be installed tightening axle, monitors the variation of torque value constantly, and when reaching predetermined torsion, motor quits work.
Usually, stubborn high pulling torque bolt etc. needs the bigger occasion of moment, generally be a kind of before adopting, general what adopt all is that current component is controlled and existing this kind electric constant torque wrench that comprises international how tame well-known producer now both at home and abroad is to the control of moment of torsion, as shown in Figure 1, it comprises control circuit (comprising current sensor 141 and controller 14) and spanner motor 13, the gear (not shown), output shaft (not shown) etc., this control circuit can be set a predetermined torque value, during work, control module in this controller utilizes electronic switch 12 that the electric power of power supply 11 is supplied with motor 13 to drive its rotation and to export and output torque through reducing gear, the current signal value of received current sensor 141 detections simultaneously, through and with the value of predetermined torque after according to default curvilinear function conversion relatively, when reaching desired numerical value, utilize electronic switch 12 to close the power supply of power machine, to realize deciding torque operation, its realization normally is connected in series to current sensor 141 in the power supply circuits, when electric wrench is worked, just there is electric current to pass through on the current sensor 141, just can produce voltage at current sensor 141, the comparator that this voltage is issued in the controller again (can utilize default transformation model conversion to compare, perhaps utilize the table of comparisons that stores in advance to compare) set normal voltage with predetermined torque and compare, to judge whether turn-offing electronic switch.
Though, this simple Current Control is fairly simple, but this is under the electric current and moment of torsion relation under perfect condition, yet find after deliberation: it is very big that the fluctuation of output torque and variation are influenced by the spanner rotating speed of motor, and the spanner motor is as the load of a current mode, and electric current changes not obvious or basic no change in work moment fuctuation within a narrow range.Also just state, in actual condition, when little moment of torsion is exported, the change in torque amplitude is big, and the electric current amplitude of variation is little, in the time of high pulling torque control output, the change in torque amplitude is little, the electric current amplitude of variation is very big, and particularly in the fully loaded output of spanner motor or overload, torque curve and current curve functional relation are very complicated! And when starting, the spanner motor is static, and starting current is very big, is 5 to 7 times of operate as normal, has almost contained the current value of all moment of torsion output areas, when only catching electric current and will cause starting just protection shut down! Because certain Dao Siya of bolt has manufacturing deficiency, perhaps Si Yali is embedded with the foreign matter of fine sand and so on to reality, also can allow the electric current of spanner motor increase suddenly, causes detecting mistake in tight bolt in addition! Thereby it has following shortcoming, takes the constant torque wrench of current component control technology can only realize the rough formula stepping control of moment of torsion, and control accuracy is low, and can't realize the electrodeless adjusting of torsion output, its poor anti jamming capability.Thereby the existing section switch that normally adopts arranges predetermined torque, thereby it far can not satisfy the working condition requirement that high accuracy is used.
In addition, because find when immediate current Acquisition Detection precision can't satisfy in the past with Current Control that electric current is in a hundreds of milliampere variation, torsion is inconsistent in the linearity that the different performance curve of spanner motor does work, that is to say that electric current rises very fast in the little moment of torsion of control output, and change in torque is not obvious, change in torque is fast in high pulling torque output, electric current changes amplitude also very greatly simultaneously, even be doubled and redoubled, so the design of hardware just has great difficulty.
The utility model content
Because the problems referred to above, the utility model purpose is to provide a kind of and can steplessly sets, and can adopt the numerical control electric constant torque wrench of many index controls (for example revolution, electric current, voltage).Novel wrest fixing spanner of the present utility model increases spanner rotating speed of motor Data Detection except using current component control data, and by the functional relation between the fluctuation of electric current and rotating speed, and form a kind of new method of controlling output torque.In addition, in the inelastic region of spanner motor outputting torsion, can take interpolation algorithm, can the control accuracy of spanner motor in whole output torque scope significantly being improved.
For reaching above-mentioned purpose, a kind of torque control method for the numerical control electric constant torque wrench of the present utility model, it comprises step:
1) sets a predetermined torque value and send a control circuit to;
2) this control circuit utilizes an electronic switch that power supply is supplied with the spanner motor to drive its rotation and to export and output torque through reducing gear;
3) this control circuit detects this spanner rotating speed of motor, and compares with the predetermined torque value;
4) when reaching desired numerical value, utilize electronic switch to turn-off the power supply of spanner motor.
Further:
This control circuit is to utilize the function model conversion of the rotating speed-moment of torsion that prestores to compare.
In step 2) in, this electronic switch is to trigger power regulation circuit or this electronic switch is that a controllable silicon phase shift triggers power regulation circuit and power supply is supplied with the spanner motor by the controllable silicon phase shift.
This controller is selected the current work interval of suitable this electric wrench according to this predetermined torque value, and control silicon controlled conduction angle is delivered to the electric current of spanner motor in this current work interval with control.
It is constant to control this current value that this controller also receives the current value of this spanner motor that a current sensor detects.
In step 2) in, at first utilize current sensor to detect the operating current of spanner motor, and judge the work section that it is in, carry out subsequent step then to utilize corresponding transformational relation curve model control torque.
The utility model also provides a kind of numerical control electric constant torque wrench, and it comprises:
A spanner motor;
A gear;
An output revolving shaft, this spanner motor rotate and pass through this output revolving shaft output torque through this reducing gear;
A moment of torsion setting device;
An electronic switch is electrically connected on this spanner motor to control the on/off of this spanner motor;
A spanner motor speed sensor detects this spanner rotating speed of motor and exports a tach signal;
A controller, this controller can receive the predetermined torque that the moment of torsion setting device arranges, and can receive this tach signal and carry out logic relatively with this predetermined torque value, and when described tach signal value reaches the predetermined torque requirement, control this electronic switch and turn-off so that this spanner motor stall.
Further, this electronic switch comprises a controllable silicon phase-shift trigger circuit.
This controller comprises an operating current and selects module, and this electric current selects module to select a given drive current according to the predetermined torque value, and makes this controller control this this given drive current of controllable silicon phase-shift trigger circuit output to this spanner motor.
It also comprises a current sensor, and it detects the operating current of this spanner motor and export a current signal and feeds back to this controller.
It also comprises a current sensor, it detects the operating current of this spanner motor and exports a current signal and feeds back to this controller, this controller comprises an operating current section comparator, this operating current section comparator received current signal is also exported an operating current section signal, and the logic that this controller selects a rotating speed-moment of torsion transformation model to carry out tach signal predetermined torque value according to this operating current section signal compares.
Also comprise a constant-current circuit and be electrically connected between this spanner motor of this electronic switch, and the electric current that receives the output of this controller selects signal to export a given drive current to this spanner motor.
This controller is that the silicon controlled conduction angle in the control controllable silicon phase-shift trigger circuit is constant with the control output current.
This moment of torsion setting device is stepless stored digital formula input unit.
This controller is Programmable Logic Controller or single-chip microcomputer.
The curve of a plurality of electric current-rotating speeds of the memory stores of Programmable Logic Controller or single-chip microcomputer-moment of torsion.
The beneficial effects of the utility model are, the utility model by with spanner rotating speed of motor data as control main points, improved control resolution, the motor that is that can be artificial is created three work torque curves of containing mutually, with this original comparatively mild torque curve is converted to steeper torque range curve, widened the difference of initial moment and overload torque, thereby scope and the precision of control output are significantly improved.Fact proved its control accuracy can reach ± 3%; Thereby can satisfy the demand of the electrodeless adjusting of torsion output, and its antijamming capability is strong.Can significantly improve the control accuracy of motor in whole output torque scope.And the applicability of electric wrench is strengthened greatly, even also can reach the requirement of high accuracy use in the power supply instability area.
Description of drawings
Fig. 1 is the structural representation of existing electric constant torque wrench;
Fig. 2 is the structural representation of the utility model one specific embodiment;
Fig. 3 is the structural representation of another specific embodiment of the utility model;
Fig. 4 is the workflow schematic diagram of the utility model one specific embodiment;
Fig. 5 is the workflow schematic diagram of another specific embodiment of the utility model.
Main Reference numeral:
11 power supplys
12 electronic switches
13 spanner motors
14,24 control circuits
241 speed probes
141 current sensors.
The specific embodiment
In order to make the feature of utility model, advantage can further be understood, and elaborates it below in conjunction with the accompanying drawing specific embodiment that develops simultaneously:
As Fig. 2 and shown in Figure 4, be structural representation and the workflow schematic diagram of the utility model one specific embodiment, it may further comprise the steps:
1, sets a predetermined torque value and send a control circuit 24 to;
2, this control circuit utilizes electronic switch that power supply 11 is supplied with spanner motor 13 to drive its rotation and to export and output torque through reducing gear;
3, detect the rotating speed of this spanner motor 13, and carry out logic (by rotating speed-moment of torsion relation curve model relatively) relatively with the predetermined torque value;
4, when torque value reaches desired numerical value, utilize electronic switch 12 to turn-off the power supply of spanner motor 13.
That is to say, it comprises power supply 11, electronic switch 12, control circuit (comprising speed probe 241 and controller 24) and spanner motor 13, gear (not shown), output shaft (not shown) etc., this control circuit can be set a predetermined torque value, during work, at first, by a moment of torsion setting device one predetermined torque value is set, this moment of torsion setting device can be various input equipments such as dial, button, it is preferably and adopts the setting of stored digital formula input unit, can satisfy the demand of stepless adjustment.
Then, utilize electronic switch 12 that power supply 11 is supplied with spanner motor 13 to drive its rotation and to export and output torque through reducing gear;
Simultaneously, utilize a speed probe 241 to detect this spanner rotating speed of motor, and compare with the predetermined torque value, when reaching desired numerical value, utilize electronic switch to close the power supply of power machine.
Wherein this rotating speed can be with the used time representation of turning around of spanner motor, and the torque wire sexual intercourse of the decline of the no-load voltage ratio constant by mechanical part and spanner motor speed and reaction force (namely utilizing a default function model that rotating speed is converted to the work moment values) convert to real-time moment of torsion with the predetermined torque value relatively, it will be understood by those skilled in the art that, can also earlier the predetermined torque value be converted to the corresponding preset rotating speed in advance by said method compares then, normally store the transformational relation curve model in this controller, the manner of comparison that it is concrete and switch technology can be identical with the technology of existing Current Control formula electric wrench.
The utility model comes control torque owing to the moment of torsion of the decline that utilizes the spanner motor speed and reaction force is linear, and its linearity is fine, it is in the preferable working region of electric wrench, torque curve and speed curves functional relation linear fine, and its conversion constant substantially constant, thereby can satisfy the requirement of control accuracy 1% to 3%, this control scheme can satisfy the requirement that moment of torsion is decided in stepless adjustment output.
When but the operation interval of working as electric wrench is bigger, the linear meeting of moment of torsion of the no-load voltage ratio constant of mechanical part and the decline of spanner motor speed and reaction force exists bigger variation, be during in small-power output or high-power output at the spanner motor for example, its conversion constant has bigger variation, in order to make electric wrench that big operation interval can be arranged, it can further increase index control.
Find under study for action, preferably utilize detected current value to distinguish the interval of spanner motor acting, that is to say that the purpose that detects electric current is that detection spanner motor is in small-power work or power output, with this, can make by in the later interval of current segmenting, utilize that the moment of torsion of the decline of spanner motor speed and reaction force is linear to come control torque, and its linearity is fine, can satisfy the requirement of control accuracy 1% to 3%, this control scheme can satisfy the requirement that moment of torsion is decided in stepless adjustment output.That is to say that in the interval of the acting of dividing, its precision is finished by rotating speed after current detecting.
Therefore, as 3 and shown in Figure 5, be structural representation and the workflow schematic diagram of another specific embodiment of the utility model; In another specific embodiment of the present utility model, at first be according to default output torque, the given drive current that the moment of torsion that utilization prestores-current work Model Selection one is fit to, and provide with this given drive current and to give the electric wrench motor and carry out operation, its the linear conversion constant of moment of torsion that can guarantee the decline of spanner motor speed this moment and reaction force is constant, preferable adopted controllable silicon phase shift triggers the given method of Power Regulation, concrete, can adopt the mode of phase shift exactly, by detecting the zero point of alternating current, control silicon controlled conduction angle, utilization begins conducting at specific conduction angle, make the spanner motor can be in half worker or lower operating mode work, this moment, its operating current can roughly be maintained in the required scope, can strengthen the output torque scope of electric wrench like this, and keep higher moment of torsion output that can stepless setting, its advantage be such as, the working range of spanner can only be at 600 Ns of rice to 1200 Ns of rice when not controlling spanner motor input current, increase this control and can allow working range expand 200 Ns of rice to 1200 Ns of rice, and guarantee precision.
Present embodiment comprises step:
1, sets a predetermined torque value and send a control circuit 24 to;
2, this control circuit 24 utilizes electronic switch that power supply 11 is supplied with the controllable silicon phase shift and triggers power regulation circuit 31 electric power;
3, this controller 24 is according to this predetermined torque value, according to the contrast table of storing in advance, select the current work interval of suitable electric wrench, and control silicon controlled conduction angle is to control and to drive 13 rotations of spanner motor and to export and output torque (control silicon controlled conduction angle makes the electric current that is delivered to the spanner motor in this current work interval) through reducing gear;
4, detect the rotating speed of this spanner motor 13, and carry out logic relatively with the predetermined torque value;
5, when reaching desired numerical value, utilize electronic switch 12 to turn-off the power supply of spanner motor 13.
Certain given electric current is not limited to said method, it will be understood by those skilled in the art that, can also adopt other constant current technology to reach the requirement of control motor operating mode, one constant-current circuit for example can be set to be electrically connected between this spanner motor of this electronic switch, and receive the electric current selection signal that this controller is exported, to export a given drive current to this spanner motor.And preferable can directly contain electronic switch with the handoff functionality of power supply 11 with controllable silicon phase shift triggering power regulation circuit 31, to simplify circuit.
In addition, this numerical control electric constant torque wrench also can comprise a current sensor 141, and it detects the operating current of this spanner motor and export a current signal and feeds back to this controller; And make this controller with this current signal corrected parameter as a comparison.
In the specific embodiment more of the present utility model, its control design is basic identical with said method, be with above-described embodiment difference, it is not the scope of selecting operating current earlier, but at first utilize current sensor to detect motor working current, and judge the work section that it is in, utilize corresponding transformational relation curve to utilize that the moment of torsion of the decline of spanner motor speed and reaction force is linear to come control torque then.Concrete is exactly the function model that this control circuit can be stored rotating speed-electric current-moment of torsion, in this specific embodiment, it is to select suitable rotating speed-moment of torsion transformation model according to the current value of real work, thereby this method can make this numerical control electric constant torque wrench realize wideer working range.
In sum, the utility model mainly is that the moment of torsion of deciding that can utilize detected rotating speed and current data to control the numerical control electric constant torque wrench is jointly controlled, it controls main points with rotary speed data as precision, and with the data of the current acquisition condition as segmentation, and set up the function model of rotating speed-electric current-moment of torsion, to form a kind of new method of controlling output torque, and but the control of above-mentioned control method application chip (is for example used Programmable Logic Controller, perhaps single-chip microcomputer is controlled) and be that basic point is to the modeling of whole spanner motor output torque scope with these data, improved control resolution, thereby the control of output torque is greatly improved, fact proved its control accuracy can reach ± 3%.In addition, in the inelastic region of spanner motor outputting torsion, also can take interpolation algorithm, can the control accuracy of spanner motor at whole output torque significantly being improved.
Preferable, this controller can utilize the curve of a plurality of electric current-rotating speeds of the memory stores of Programmable Logic Controller or single-chip microcomputer-moment of torsion, to select according to demand.
In sum, the utility model can reach above-mentioned all function and purpose really.But the above only is preferred embodiment of the present utility model, when not limiting the utility model practical range with this; Therefore, allly change and modify according to the utility model claim and the simple equivalent done of creation description, all should still belong in the scope that the utility model patent contains.