CN102087157A - Double-lever force standard machine and calibration and demarcation method thereof - Google Patents

Abstract

The invention discloses a double-lever force standard machine and a calibration and demarcation method thereof, aiming to solve the problems of complex structure, limited applied force value level, low efficiency and the like in the prior art. The force standard machine comprises a loading lever system and a balancing lever system, wherein the loading lever system comprises a synchronous belt and an eccentric wheel tensioning mechanism; the balancing lever system comprises a balance weight; the eccentric wheel tensioning mechanism comprises an eccentric shaft, a spring check ring, a bearing, a spacer bush and bolts; and the balance weight is in an upper-lower or left-right double-body dismounting structure and comprises an additional balance weight, an original balance weight, a stop pin and fastening bolts. The calibration and demarcation method comprises the following steps of: calibrating zero balance; placing a gravity weight on the upper end surface of a lower beam of a reverse frame; calibrating zero balance again; recording the weight displacement; and representing the displacement directly by the pulse number of a coder and the like. The invention also provides a calibration and demarcation method for the double-lever force standard machine by the balance weight.

Description

Double lever type force standard machines and calibration thereof and scaling method

Technical field

The present invention relates to the accurate power value charger of a kind of lever and calibration and scaling method, more particularly, the present invention relates to a kind of double lever type force standard machines and calibration and scaling method.

Background technology

The metering of power value is the basic measurement technology that plays an important role in the development of the national economy.At one of the most basic equipment of power value metering field and instrument is force standard machines, and wherein the lever force standard machines is extremely extensive in dynamometer development, the various applications producing, use.In weapons such as cannon are produced, utilize the plastic yield manometry to measure breech pressure, be widely used, it needs accurate power value bringing device.

There is following shortcoming in the existing lever force standard machines (perhaps charger) that is used for above-mentioned purpose: complex structure, and it is limited to apply the power numerical series, and efficient is low, the cost height, automaticity is low, uses inconvenience etc.

For solving the problems of the technologies described above, need new force standard machines and new technical method.

Summary of the invention

Technical matters to be solved by this invention is to have overcome the problem that prior art exists, and a kind of double lever type force standard machines is provided.The calibration and the scaling method of double lever type force standard machines also are provided simultaneously.

For solving the problems of the technologies described above, the present invention adopts following technical scheme to realize: described double lever type force standard machines comprises lever system and the balanced lever system of loading, load lever system and comprise synchronous band, dull and stereotyped and eccentric wheel strainer, the balanced lever system comprises counterweight counterweight and zero balance lever crossbeam.Described counterweight counterweight is for up and down or left and right sides binary detaching structure, and the counterweight counterweight is made up of additional bob-weight counterweight, former counterweight counterweight, register pin and trip bolt.

Former counterweight counterweight is fixed on the left end of zero balance lever crossbeam, and the additional bob-weight counterweight contacts with former counterweight counterweight left side or bottom surface by register pin, fixes with trip bolt again.

Eccentric wheel strainer described in the technical scheme comprises excentric shaft, 2 spring collars, a N bearing, spacer and screws.Described excentric shaft one end is arranged to step or cubic cylinder or hexagonal prism body, is that the e place has through hole at the center line deviation distance of excentric shaft, and the axis of rotation of this through hole is parallel with the center line of excentric shaft, adopts screw that excentric shaft is fastened on the flat board.Be set with spring collar, bearing, a N described bearing and described spring collar on the excentric shaft successively.The outer race of N bearing contacts with being with the no flank of tooth synchronously, between the endoporus of N bearing and the excentric shaft is that slight interference cooperates, when the width of N bearing is spent less than synchronization bandwidth, add a spacer and make the width of the width sum of N bearing and spacer more than or equal to synchronous band between bearing, N gets the natural number more than or equal to 1.

A kind of described double lever type force standard machines utilize gravity counterweight W _BCalibration and scaling method, comprise the steps:

1. at first the double lever type force standard machines is carried out the zero balance calibration;

2. placing gravity in the upper surface of reverse frame sill is W _BThe gravity counterweight;

3. implement the zero balance calibration once more;

4. remember counterweight displacement L ₁, the acting force of unit displacement then

5. for easy to use, displacement L ₁Directly represent, so the k acting force k of individual pulse with the umber of pulse of scrambler _pReplace,

k _p=W _B/ p ₁, wherein p1 is that counterweight moves L ₁The umber of pulse of range encoder output.

A kind of described double lever type force standard machines utilize counterweight W ₁Calibration and scaling method, comprise the steps:

1. the utilization force cell is determined Δ (W ₁S ₁);

2. promptly add Δ (W in the change counterweight ₁S ₁) situation under carry out the calibration of zero balance;

3. remove Δ (W ₁S ₁), in the test specimen installation site that is applied in the power value force cell is installed;

4. by moving moving crossbeam the reverse bridge joint of force cell and loading is touched, be in horizontality until the main lever crossbeam;

5. read the data of force cell, to determine Δ (W ₁S ₁) the power value changes delta P that causes;

6. by moving moving crossbeam the reverse frame of force cell and loading is disengaged, mobile counterweight makes main lever crossbeam Reversion Level state, writes down and calculate displacement Δ L ₀, record scale-up factor

Δ L ₀Can use umber of pulse p ₀Expression, scale-up factor

Also can use the power value of unit pulse

Expression,

In the formula: Δ L ₀. the counterweight displacement variable, Δ P. changes Δ (W ₁S ₁) the power value that causes changes.

Utilize gravity counterweight W _BWith utilize counterweight W ₁The calibration of the zero balance described in the technical scheme of two kinds of calibrations and scaling method comprises the steps:

1. when calibrating reverse frame is separated with moving crossbeam, promptly

In P=0;

2. make counterweight move to position about the zero point that differential transformer indication main lever crossbeam is in horizontality, finely tune counterweight then at null position L ₀, this moment differential transformer be presented at ± be that the main lever crossbeam is in horizontality within the 0.015mm scope, after this, as long as remember then to need not zero point to implement again zero balance;

3. by the displacement transducer record counterweight position at zero point on the main lever crossbeam.

Compared with prior art the invention has the beneficial effects as follows:

1. double lever type force standard machines of the present invention moves the change lever ratio by the counterweight that adopts fixed mass along lever crossbeam and reaches the purpose that change applies power value size, the counterweight that has saved traditional lever force standard machines complexity adds unloading system, and machine construction is simplified.Adopt the double lever structure on this basis, promptly adopt balanced lever, realize double lever type force standard machines natural equilibrium at zero point, need not in use change because of test specimen and changed zero point have to implement zero balance by the counterweight of adjusting balanced lever.

2. the counterweight of the balanced lever in the double lever type force standard machines of the present invention is made the binary demountable structure, can play simultaneously to reduce equipment volume and the double effect of doing demarcation.

3. can calibrate at any time the zero point of double lever type force standard machines of the present invention, and calibration steps is simple, promptly can realize by the position of automatic change counterweight on crossbeam.

4. the scaling method of double lever type force standard machines of the present invention is easy, reliable, can adopt the gravity counterweight to demarcate.The gravity counterweight is placed on the reverse frame sill upper surface, promptly can realizes demarcation double lever type force standard machines of the present invention as long as measure counterweight moves on the main lever crossbeam under the weight application counterweight anterior-posterior balance state distance.

5. sample is insensitive to the influence of power value in the installation site of double lever type force standard machines of the present invention.

6. the eccentric wheel strainer is adopted in the synchronous band transmission of mobile counterweight in the double lever type force standard machines of the present invention, and compact conformation is easy to use and reliable.

Description of drawings

The present invention is further illustrated below in conjunction with accompanying drawing:

The axonometric projection graph (not cuing open electrical control cubicles) that Fig. 1 forms for the structure of dissecing along the vertical plane of symmetry of main lever crossbeam of double lever rider formula force standard machines of the present invention;

Fig. 2 is the mechanism model and the statical equilibrium schematic diagram of double lever type force standard machines of the present invention;

Fig. 3 is the fundamental diagram of double lever type force standard machines of the present invention when the test specimen setting-up eccentricity;

Fig. 4 is double lever type force standard machines of the present invention equivalence fundamental diagram when the test specimen setting-up eccentricity;

Fig. 5-a is 50kN double lever rider formula force standard machines zero adjustment of the present invention and power value calibration structural representation;

Fig. 5-b is the axonometric projection graph of the exploded representation formed of the structure of placing about counterweight counterweight in the 50kN double lever rider formula force standard machines of the present invention;

Fig. 6-a is the axonometric projection graph that the structure of placing up and down of the counterweight counterweight in the double lever rider formula force standard machines of the present invention is formed;

Fig. 6-b is the axonometric projection graph of the exploded representation formed of the structure of placing up and down of the counterweight counterweight in the double lever rider formula force standard machines of the present invention;

Fig. 7-a is the axonometric projection graph that the structure of the eccentric wheel strainer in the double lever rider formula force standard machines of the present invention is formed;

Fig. 7-b is the axonometric projection graph of the exploded representation formed of the structure of the eccentric wheel strainer in the double lever rider formula force standard machines of the present invention;

Fig. 8-a is the FB(flow block) of the zero balance calibration steps of double lever rider formula force standard machines of the present invention;

Fig. 8-b is the FB(flow block) of the gravity counterweight scaling method of double lever rider formula force standard machines of the present invention;

Fig. 8-c is the FB(flow block) of the counterweight scaling method of double lever rider formula force standard machines of the present invention;

Among the figure: 1. the force cutter holds, 2. servomotor, and 3. fulcrum pivot holds, 4. workpiece, 5. moving crossbeam, 6. zero balance lever crossbeam, 7. electrical control cubicles, 8. ball-screw, 9. main lever crossbeam, 10. counterweight, 11. differential transformers, 12. gravity counterweights, 13. levers the 2nd force cutter holds, 14. lever the 2nd fulcrum pivot holds, 15. additional bob-weight counterweights, 16. former counterweight counterweights, 17. register pins, 18. trip bolt, 19. counterweight counterweights, 20. excentric shafts, 21. spring collars, 22. bearing, 23. spacers, 24. screws, 25. flat boards.

Embodiment

Below in conjunction with accompanying drawing the present invention is explained in detail:

One. double lever rider formula force standard machines

Consult Fig. 1, the force standard machines of double lever rider formula structure is formed by loading lever system, balanced lever system, mainframe, reverse frame and electrical control cubicles 7.Load that lever system comprises that eccentric wheel strainer, force cutter hold 1, servomotor 2, fulcrum pivot hold 3, ball-screw 8, main lever crossbeam 9, counterweight 10 and differential transformer 11.

The balanced lever system comprise counterweight counterweight 19, zero balance lever crossbeam 6, lever the 2nd force cutter hold 13 with lever the 2nd fulcrum pivot hold 14.

Load lever system and balanced lever system respectively by fulcrum pivot hold 3 and lever the 2nd fulcrum pivot hold 14 and be installed on the mainframe one on the other, main lever crossbeam 9 in the loading lever system and zero balance lever crossbeam 6 horizontal positioned in the balanced lever system, and be in the same vertical plane, promptly load the top that lever system is positioned at the balanced lever system.Load lever system according to the work of second-class lever principle, its fulcrum is positioned at the left end of lever, and the force is positioned at the middle part of lever.The balanced lever system is according to the work of lever of first order principle, and its fulcrum is positioned at the middle part of lever, and the force is positioned at the right-hand member of lever.The bar that the force of the force of main lever crossbeam 9 and zero balance lever crossbeam 6 is held 1, centre reverse frame is arranged by the force cutter holds 13 with lever the 2nd force cutter and is connected, main lever crossbeam 9 and the fulcrum of zero balance lever crossbeam 6 equate that with distance between the force fulcrum of the fulcrum of main lever crossbeam 9 and zero balance lever crossbeam 6 is positioned on the same pedal line.The counterweight 10 that loads lever system can be along main lever crossbeam 9 accurate shift positions, thus the size of change lever ratio; Zero balance lever crossbeam 6 can balance main lever crossbeam 9 and the gravity of counterweight 10, and the left end device of zero balance lever crossbeam 6 has the adjustable counterweight counterweight 19 of fixed mass.

The utilization lever balance theory is realized force standard machines natural equilibrium at zero point; By changing the position of counterweight 10 on main lever crossbeam 9, reappear the zero balance state and finish zero adjustment; Utilize less gravity counterweight to reach force standard machines is carried out the purpose that the power value is demarcated.

Consult Fig. 5 and Fig. 6, counterweight counterweight 19 is binary demountable structures, it both can make the counterweight counterweight 19 of demountable structure up and down, also can make the counterweight counterweight 19 of left and right sides demountable structure, promptly counterweight counterweight 19 is made up of with trip bolt 18 additional bob-weight counterweight 15, former counterweight counterweight 16, register pin 17.Former counterweight counterweight 16 adopts the left end of screw retention at zero balance lever crossbeam 6, and additional bob-weight counterweight 15 contacts with former counterweight counterweight 16 left sides or location, bottom surface by register pin 17, and is fixing with trip bolt 18 again.Wherein additional bob-weight counterweight 15 can take off or change as required, changes the natural equilibrium null position, reaches the purpose that reduces equipment volume.

Consult Fig. 7, along main lever crossbeam 9 ball-screw 8 is installed vertically, the left end of main lever crossbeam 9 is equipped with servomotor 2, be equipped with dull and stereotyped 25 on the left side of main lever crossbeam 9, servomotor 2 output shafts pass and are equipped with synchronous pulley from dull and stereotyped 25 lower ends, the left end of ball-screw 8 passes and is equipped with synchronous pulley from dull and stereotyped 25 upper ends, and servomotor 2 drives ball-screw 8 rotations by bringing synchronously.Counterweight 10 is driven by the feed screw nut on the ball-screw 8 and moves along the rolling guide on the main lever crossbeam 9, and servomotor 2 changes the position of counterweight 10 on main lever crossbeam 9 by being with synchronously, and the eccentric wheel strainer is adopted in the tensioning of band synchronously.The principle work that this eccentric wheel strainer changes according to the radial dimension of an excentric shaft its outside surface when center line turns round.The eccentric wheel strainer is made up of with screw 24 excentric shaft 20, spring collar 21, bearing 22, spacer 23 that a N structure is identical.

Excentric shaft 20 1 end end faces are that non-smooth surface is used to increase friction force, and the other end is manufactured with step or the cubic cylinder or the hexagonal prism body that can use Wrench.With the center line deviation distance of excentric shaft 20 be that the e place has through hole, the axis of rotation of this through hole is parallel with the center line of excentric shaft 20, adopts screw 24 that excentric shaft 20 is fastened on dull and stereotyped 25, screw 24 plays the effect of centralized positioning when excentric shaft 20 rotates.When bearing 22 is one, be set with spring collar 21, spring collar 21 that bearing 22 is identical with another structure on excentric shaft 20 outer rims (external cylindrical surface) successively, the endoporus of bearing 22 bearing inner rings is that slight interference cooperates with excentric shaft 20 outer rims (external cylindrical surface).After the assembling of eccentric wheel strainer was finished, the external cylindrical surface of the outer race of bearing 22 contacted with being with the no flank of tooth synchronously, and the width of bearing 22 outer races is not less than the synchronization bandwidth degree.When excentric shaft 20 when screw 24 central axis turn round, synchronously band inwardly the maximum displacement of (tooth one example is arranged) equal the twice of the eccentric distance e of excentric shaft 20.Bearing 22 can be one, also can be more than or equal to 2, when the quantity of bearing 22 is during more than or equal to 2, be set with spring collar 21 successively on excentric shaft 20 external cylindrical surfaces, bearing 22, the bearing 22 that another structure is identical, the 3rd spring collar 21 that bearing 22...... is identical with another structure, that is to say, be set with spring collar 21 on the excentric shaft 20 successively, bearing 22, N the bearing 22 and described spring collar 21 that structure is identical, the face of cylinder of N bearing 22 outer races contacts with being with the no flank of tooth synchronously, between the endoporus of N bearing 22 and the excentric shaft 20 is that slight interference cooperates, and N gets the natural number more than or equal to 1.Overall width more than or equal to the identical bearing 22 of 1 structure is not less than the synchronization bandwidth degree.If the width more than or equal to the identical bearing 22 of 1 structure is slightly less than the synchronization bandwidth degree, can between any two bearings 22, install a spacer 23 additional, the width sum that makes N bearing 22 and spacer 23 is more than or equal to the width of band synchronously.Realize by the spring collar 21 at two ends more than or equal to 1 bearing 22 and the axial location of spacer 23 on excentric shaft 20.Bearing 22 is selected zanjon formula ball bearing, e=3mm among the embodiment for use.

The external cylindrical surface of bearing 22 outer shrouds that are sleeved on excentric shaft 20 outer rims is contacted with being with the no flank of tooth synchronously, the step of pulling on the excentric shaft 20 with Wrench (or cubic cylinder or hexagonal prism body) makes excentric shaft 20 turn round around screw 24 central axis, adjust excentric shaft 20 outer rims and promptly adjust excentric shaft 20 outer rims and the radial dimension of the belt vertical direction that is tensioned with the displacement of the belt vertical direction that is tensioned, the eccentric wheel strainer will be realized effective transmission of band synchronously with compressing synchronously by the bearing on the excentric shaft 20 22.The maximum displacement of excentric shaft 20 outer rims and the synchronous band vertical direction that is tensioned equals the twice of the eccentric distance e of excentric shaft 20.

Two. the scaling method of double lever type force standard machines

Double lever type force standard machines zero balance, zero adjustment and demarcation based on lever amplification principle have material impact to the force standard machines serviceability.The present invention provides a kind of scaling method of double lever rider formula force standard machines simultaneously, and it effectively solves zero balance, zero adjustment and the power value of double lever rider formula force standard machines and demarcates problem.

I. the ultimate principle of double lever type force standard machines

Consulting Fig. 2, is double lever rider formula force standard machines structural model and statical equilibrium principle shown in the figure.Its middle and upper part lever is a main lever crossbeam 9, play a part directly the test specimen imposed load, according to the work of second-class lever principle, its left end fulcrum is fixed, intermediate point D is the point of application to test specimen, transportable counterweight 10 (gravity is W) as the power source on the right side and position changeable.The bottom lever is a zero balance lever crossbeam 6, and according to the work of lever of first order principle, its intermediate support is fixed, and left end is that (gravity is W to counterweight counterweight 19 ₁), right endpoint plays a part main lever crossbeam 9 is applied equilibrant, has the vertical rod of reverse frame to be connected with the point of application D of main lever crossbeam 9 by a centre.Main lever crossbeam 9 is connected with the right endpoint of zero balance lever crossbeam 6 with zero balance lever crossbeam 6 parallel and horizontal positioned, the point of application D of main lever crossbeam 9, and the fixed pivot of two lever systems is positioned on the same pedal line, and two brachiums equate to be S.Main lever crossbeam 9 horizontalitys are differential transformer 11 detections of LVDT by the model that is installed on the main lever crossbeam 9.

The test specimen (for example force cell) that is applied in the power value is placed in the reverse frame of a rectangle, is that test specimen is placed on the last workplace of moving crossbeam 5 by moving crossbeam 5 supportings that are installed on the mainframe.The oppositely vertical rod up and down of frame and the test specimen axis conllinear that is applied in the power value.According to the statical equilibrium principle of lever, do not consider the friction of fixed pivot place (fulcrum pivot holds 3), the gravity of each rod member and position determine that when main lever crossbeam 9 is in balance the deadweight of establishing main lever crossbeam 9 is W ₀₁, centroid position L ₀₁, the gravity of vertical rod and reverse frame is W up and down ₀₂, the deadweight of zero balance lever crossbeam 6 is W ₀₃, centroid position L ₀₃, regarding rigid member during analysis as, the power P that then can act on the test specimen that is applied in the power value is

$P=\frac{W}{S}L+\frac{1}{S}({\mathrm{<figure-callout\; id="0"\; label="WL"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">WL</figure-callout>}}_0+W_{01}{L}_{01}+W_{02}S+W_{03}{L}_{03}-W_1{S}_1)---\left(0\right)$

If L=0 when P=0, and main lever crossbeam 9 is in level, and this moment, state was made as the zero point of double lever rider formula force standard machines, its equilibrium condition:

$\frac{1}{S}({\mathrm{<figure-callout\; id="0"\; label="WL"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">WL</figure-callout>}}_0+W_{01}{L}_{01}+W_{02}S+W_{03}{L}_{03}-W_1{S}_1)=0$

So

$P=\frac{W}{S}L---\left(1\right)$

${\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0=\frac{1}{W}(W_1{S}_1-(W_{01}{L}_{01}+W_{02}S+W_{03}{L}_{03}))---\left(2\right)$

Be size and the lever ratio that power P is proportional to the counterweight 10 (gravity is W) on the main lever crossbeam 9

If S is constant, change position (L) and the size of counterweight 10 (gravity the be W) purpose that can reach change power value P of counterweight 10 on crossbeam.Because of the counterweight 10 (gravity is W) as the power source can move along main lever crossbeam 9, so be called rider formula force standard machines.

The zero balance condition L of main lever crossbeam 9 ₀Be definite value, only relevant with main lever crossbeam 9 physical dimensions with counterweight counterweight 19, counterweight 10, irrelevant with test specimen (for example force cell).

In fact each member of double lever rider formula force standard machines is not a rigidity, but as long as stiffness of structural member is enough big, the elasticity of member can not impact system's operate as normal.

II. the power value scaling method of double lever rider formula force standard machines

1. the calibration steps of the zero balance of double lever rider formula force standard machines

Consult Fig. 8-a,,, therefore can realize the nature zero balance, need not to adjust zero point during use because it is constant to influence the factor of zero balance according to formula (2).

Realize the middle L=0 of pacing items formula (1) of nature zero balance.For double lever rider formula force standard machines shown in Figure 1, can calibrate at any time during use.

Reverse frame with rectangle when 1) calibrating separates with moving crossbeam 5, guarantees not contact, i.e. P=0 in the formula (1).

2) make counterweight 10 (gravity is W) move to main lever crossbeam 9 left ends position about zero point then, finely tune the position of counterweight 10 then, make it just in time at null position L ₀(this moment model be the differential transformer 11 of LVDT be presented at ± be that main lever crossbeam 9 is in horizontality within the 0.015mm scope).After this, as long as remember then to need not zero point to implement again zero balance.

3) memory at zero point is finished by record counterweight 10 displacement transducer of position on crossbeam.Displacement transducer can be grating, magnetic grid, also can be absolute type encoder, perhaps incremental encoder.Adopt incremental encoder to have simple in structure, with low cost, advantage of high precision.

After carrying out zero balance according to above-mentioned balance method,, promptly can find zero point after the start, need not to readjust as long as be parked in a definite position before machine is cut off the electricity supply.For improper off-position, perhaps break down, then balancing again.

For changing the double lever rider formula force standard machines that applies the different loads purpose by changing the position of counterweight 10 on main lever crossbeam 9 to reach, the W in the formula (1) is the self gravitation that loads lever system.According to formula (2), can be by changing W ₁S ₁Reach the zero balance purpose.

2. the power value scaling method of double lever rider formula force standard machines

1) workpiece installation site

Consult Fig. 3 and Fig. 4, actually be difficult to guarantee its center of effort's line and reverse frame when laying the test specimen that is applied in the power value center line of vertical rod is consistent up and down that establishing eccentric throw is e.According to mechanics principle, its equivalent stress as shown in Figure 4, statical equilibrium relation is as follows:

W(L+L ₀)-P(S-e)-W ₁S ₁-T ₁H＝0(3)

T＝T ₁

Formula (1) and (2) substitution formula (3) can be got

Pe＝T ₁H (4)

As seen, because the eccentric couple that causes of installing is offset by horizontal direction power T, the power P that acts on the test specimen that is applied in the power value is constant.

2) the power value scaling method of double lever rider formula force standard machines

(1) at first double lever rider formula force standard machines carried out the calibration of zero balance according to above-mentioned (i.e. the 1st problem) method;

(2) rod member that is connected with the right endpoint of zero balance lever crossbeam 6 at the point of application D of main lever crossbeam 9 then and oppositely the geometric center position of frame, the reverse upper surface of frame sill among Fig. 2 or Fig. 5, promptly place gravity counterweight 12 (gravity be W at A point place _B);

(3) according to above-mentioned (i.e. the 1st problem) method double lever rider formula force standard machines carried out the calibration of zero balance once more;

(4) remember that counterweight 10 displacements (are made as L ₁, generally, should be negative value with umber of pulse statement), the acting force of unit displacement then

According to off-centre the not principle of the power P size of influence on the test specimen that is applied in the power value is installed, (gravity is W to the gravity counterweight 12 that place at A point place _B) not strict to status requirement.

In order to improve calibration accuracy, should increase gravity counterweight W as far as possible _BGravity, and when making counterweight 10 move closer to equilibrium point, should move counterweight according to the equidirectional principle that shifts near.The data that record obtains are calculated as follows and the size of definite k:

Model is differential transformer 11 readings of LVDT when reading zero-bit, is designated as δ h; Write down L n time ₁And the reading δ h of each corresponding differential transformer _i,

$\stackrel{\&OverBar;}{\mathrm{\&delta;h}}=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{\mathrm{\&delta;h}}_i---\left(5\right)$

$L_1=\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\&Sigma;}}}{L}_{1i}+(\stackrel{\&OverBar;}{\mathrm{\&delta;h}}-\mathrm{\&delta;h})L/h---\left(6\right)$

Wherein L/h is near needed counterweight 10 displacements of differential transformer unit change zero point.The method of determining is to move 10 displacement resolution units (displacement resolution is 0.5 μ m) at the zero balance place, and the record shift value threshes more than three times and averages.

(5) for easy to use, displacement L ₁K directly represents, so can use the acting force k of individual pulse with the umber of pulse of scrambler _pReplace.

k _p=W _B/ p ₁, p wherein ₁Be that counterweight moves L ₁The umber of pulse of range encoder output.

3. the gravity counterweight of power value demarcation determines and installation method

1) determines gravity counterweight 12 gravity sizes according to requirement of power value measuring accuracy and displacement resolution.If the acting force k of least displacement unit, measuring accuracy requires δ, then is calculated as follows Weight gravity

$W_B>\frac{k}{\mathrm{\&delta;}}---\left(7\right)$

K wherein ^*Be the discreet value of the acting force k of unit displacement, W ^*And S ^*Be respectively the design load of counterweight 10 gravity W and galianconism length S.

Acting force k with unit pulse _pThe acting force k that replaces unit displacement,

$W_B>\frac{k_p}{\mathrm{\&delta;}}$

W _BExcept satisfying above-mentioned condition, also should guarantee N among Fig. 2 ₁＞0.For this reason, according to the statics relation,

$W_B<\frac{W_1{S}_1}{S}-(W_1+W_{02}+W_{03})-\frac{W_{03}{L}_{03}}{S}---\left(8\right)$

2) on the web member of the right endpoint of the point of application D of action of gravity main lever crossbeam 9 in Fig. 2 of the gravity counterweight 12 of timing signal installation and zero balance lever crossbeam 6, when main lever crossbeam 9 is in horizontality, the line of the point of application D of main lever crossbeam 9 and the right endpoint of zero balance lever crossbeam 6 is a pedal line, overlaps with gravity counterweight 12 gravity direction lines.

For ease of demarcate using, on the structure design make gravity counterweight 12 be installed among Fig. 2 the reverse top of frame sill with vertical rod that zero balance lever crossbeam 6 right endpoints are connected on.

III. utilize counterweight W ₁The method that double lever rider formula force standard machines is demarcated

According to formula

${\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0=\frac{1}{W}(W_1{S}_1-(W_{01}{L}_{01}+W_{02}S+W_{03}{L}_{03}))---\left(2\right)$

If W ₁S ₁Can change variation delta (W ₁S ₁), then following formula is set up

${\mathrm{\&Delta;<figure-callout\; id="0"\; label="L"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0=\frac{\mathrm{\&Delta;}\left(W_1{S}_1\right)}{W}---\left(9\right)$

Δ L ₀Be L ₀Variable quantity.

If Δ (W ₁S ₁) be constant, when recording Δ L ₀And Δ (W ₁S ₁) the power value changes delta P that causes, concern according to zero balance lever crossbeam 6 statical equilibrium

$\mathrm{\&Delta;P}=\frac{\mathrm{\&Delta;}\left(W_1{S}_1\right)}{S}---\left(10\right)$

{。##.##1},

$\frac{\mathrm{\&Delta;P}}{\mathrm{\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0}=\frac{W}{S}---\left(11\right)$

Promptly can record scale-up factor

As long as keep Δ (W ₁S ₁) be constant, because S is a constant, so Δ (W ₁S ₁) the power value changes delta P that causes is constant, therefore then can be at any time Comparative Examples coefficient as required Calibrate.

General Δ (W ₁S ₁) and Δ L ₀Be negative value, i.e. L ₀And W ₁S ₁All reduce.

Utilize counterweight W ₁Double lever rider formula force standard machines is demarcated, also should be guaranteed N among Fig. 2 ₁＞0, can get condition according to the statics relation for this reason

Δ(W ₁S ₁)＜W ₁S ₁-(W ₁+W ₀₂+W ₀₃)S-W ₀₃L ₀₃(12)

The implementation method of calibration:

1. the force cell of timing signal utilization is for the first time determined Δ (W ₁S ₁) be Δ P,

1) promptly adds Δ (W in the change counterweight ₁S ₁) situation under, carry out zero point correction according to above-mentioned (promptly in II problem the 1st problem) method.

2) the test specimen installed position that is applied in the power value then in Fig. 1 is installed a high precision force cell, and removes Δ (W ₁S ₁).

3) by moving moving crossbeam 5 the reverse bridge joint of force cell and loading is touched, be in horizontality until main lever crossbeam 9.

4) read the data of force cell, to determine Δ (W ₁S ₁) the power value changes delta P that causes.

2. and then by moving moving crossbeam 5 force cell is disengaged with loading reverse frame, follow mobile counterweight 10 and make main lever crossbeam 9 Reversion Level states, write down and calculate displacement Δ L ₀, record scale-up factor

Can calibrate at any time later on, method is to add and removing Δ (W respectively ₁S ₁) situation under carry out zero point correction according to the method described above, guarantee main lever crossbeam 9 horizontality unanimities, record counterweight 10 displacement variable are Δ L ₀According to the Δ (W that utilizes sensor to record for the first time ₁S ₁) the power value changes delta P that causes, calibrate Δ P/ Δ L ₀, promptly according to formula (11) check and correction scale-up factor

The added advantage of this method is that the gravity W and (perhaps) counterweight 10 that can reduce counterweight 10 move coverage L.Reason is that the initial balance point is by L ₀Reduced Δ L ₀, according to formula (0), the power value Δ P of increase,

$\mathrm{\&Delta;P}=\frac{1}{S}\mathrm{W\&Delta;}{\mathrm{<figure-callout\; id="0"\; label="L"\; filenames="HSA00000345719500051.png"\; state="\{\{state\}\}">L</figure-callout>}}_0$

Δ L ₀Can use umber of pulse p ₀Expression, scale-up factor

Also can use the power value of unit pulse

Expression.

Mean that under the identical condition of maximum load, WL can reduce, also promptly reduced volume.

Embodiment

A kind of 50kN double lever rider formula force standard machines, the length 2000mm of loading main lever crossbeam 9, maximum amplification ratio 18 loads scope 500N-50kN, S ₁=285mm, L ₀=240mm, S=95mm, H=1000mm loads counterweight 10 gravity W=2800N, the counterweight counterweight 19 gravity W of zero balance lever crossbeam 6 ₁=1600N, servomotor 2 power 750W, rated speed 2000rpm, the displacement resolution 0.5 μ m that counterweight 10 moves at main lever crossbeam 9.

The structure of expression 50kN double lever rider formula force standard machines is formed among Fig. 1, and it includes:

The force cutter holds 1, servomotor 2, fulcrum pivot hold 3, moving crossbeam 5, zero balance lever crossbeam 6, electrical control cubicles 7, ball-screw 8, main lever crossbeam 9 and counterweight 10.Expression 50kN double lever rider formula force standard machines zero adjustment and power value calibration structural representation among Fig. 5, wherein: (gravity is W to the counterweight counterweight 19 of additional bob-weight counterweight 15 and former counterweight counterweight 16 common formation zero balance lever crossbeams 6 ₁).Additional bob-weight counterweight 15 passes through two register pin 17 location that structure is identical with former counterweight counterweight 16, tightens together by trip bolt 18.When taking off former counterweight counterweight 16, meet Δ (W ₁S ₁)＜W ₁S ₁-(W ₁+ W ₀₂+ W ₀₃) S-W ₀₃L ₀₃The relation of formula.Add that former counterweight counterweight 16 is equivalent to zero balance lever crossbeam 6 and has increased Δ (W ₁S ₁).The additional bob-weight counterweight 15 of zero balance lever crossbeam 6 also can be to place up and down, and as shown in Figure 6, (gravity is W to the counterweight counterweight 19 of additional bob-weight counterweight 15 and former counterweight counterweight 16 common formation zero balance lever crossbeams 6 ₁).Additional bob-weight counterweight 15 passes through two register pin 17 location that structure is identical with former counterweight counterweight 16, tightens together by trip bolt 18.When taking off former counterweight counterweight 16, coincidence formula Δ (W ₁S ₁)＜W ₁S ₁-(W ₁+ W ₀₂+ W ₀₃) S-W ₀₃L ₀₃Relation.Add that former counterweight counterweight 16 is equivalent to zero balance lever crossbeam 6 and has increased Δ (W ₁S ₁).

Double lever rider formula force standard machines is according to preceding method and rule, and suitable parameters is chosen in design makes it be in the zero-bit natural equilibrium.The sign of balance is a formula

In P=0, main lever crossbeam 9 is in horizontality.Horizontality detects by differential transformer 11, departs from zero-bit ± 0.015mm with the interior lever level that is considered as with differential transformer 11.Adopt servomotor 2 to rotate on the structure, drive counterweight 10 by nut and move along the rolling guide on the main lever crossbeam 9 through the ball-screw of band driving synchronously 8.For for simplicity, use the displacement that incremental encoder that servomotor 2 carries is measured counterweight 10 (gravity is W), and the segmentation function of utilization servoamplifier reaches the purpose that improves resolution with scrambler output segmentation.The umber of pulse that servomotor 2 carries scrambler is 2500,8 frequencys multiplication, becomes 20000 after segmentation.

To the zero adjustment that double lever rider formula force standard machines carries out, be by the position of mobile counterweight 10 on main lever crossbeam 9, make main lever crossbeam 9 be in the horizontal level of requirement, this moment formula In P=0.

To the demarcation that double lever rider formula force standard machines carries out, be to determine to work as formula Unit pulse changed the power value variation that causes when middle P was non-vanishing, used k _pExpression, k _pIt is the pulse representation of k.

Consult Fig. 5, adopt the gravity of gravity counterweight 12 to demarcate, get W _B=77.45N departs from zero-bit ± 0.015mm with interior main lever crossbeam 9 levels that are considered as with differential transformer 11, adopts incremental encoder to measure the displacement of counterweight 10 (gravity is W), records corresponding L ₁The umber of pulse p of distance ₁=22275, demarcate coefficient k _p=0.00685N/p.According to formula (7), establish δ=0.01%, then calculate W _BCalculated value be 68.5N, meet the demands.

Adopt counterweight to carry out the power value calibration, get Δ (W ₁S ₁)=190000Nmm, S=95mm.At first utilize the high precision force sensor demarcating, Δ (W is being installed ₁S ₁) situation under carry out zero adjustment, take off Δ (W then ₁S ₁), force cell is installed, move moving crossbeam 5 and make main lever crossbeam 9 be in level, depart from zero-bit ± 0.015mm with the interior lever level that is considered as with differential transformer 11.Demarcate coefficient delta P=2000N; Mobile counterweight 10 is not being installed Δ (W ₁S ₁) situation under carry out zero adjustment.Record is from being equipped with Δ (W ₁S ₁) situation under zero-bit rise, counterweight 10 moves the umber of pulse of passing by, and is Δ L ₀Corresponding umber of pulse gets p ₀=291600, so k _p=0.00685N/p.

W wherein ₁=2200N, W ₀₂=200N, W ₀₃=100N, L ₀₃=47mm, S ₁=200mm

Calculate

Δ(W ₁S ₁)+(W ₁+W ₀₂+W ₀₃)S+W ₀₃L ₀₃≈432200Nmm

W ₁S ₁＝440000

Satisfy condition

Δ(W ₁S ₁)＜W ₁S ₁-(W ₁+W ₀₂+W ₀₃)S-W ₀₃L ₀₃

Claims (5)

1. double lever type force standard machines, comprise lever system and the balanced lever system of loading, load lever system and comprise synchronous band, flat board (25) and eccentric wheel strainer, the balanced lever system comprises counterweight counterweight (19) and zero balance lever crossbeam (6), it is characterized in that, described counterweight counterweight (19) is for up and down or left and right sides binary detaching structure, and counterweight counterweight (19) is made up of with trip bolt (18) additional bob-weight counterweight (15), former counterweight counterweight (16), register pin (17);

Former counterweight counterweight (16) is fixed on the left end of zero balance lever crossbeam (6), and additional bob-weight counterweight (15) contacts with former counterweight counterweight (16) left side or bottom surface by register pin (17), uses trip bolt (18) fixing again.

2. according to the described double lever type force standard machines of claim 1, it is characterized in that described eccentric wheel strainer comprises excentric shaft (20), 2 spring collars (21), a N bearing (22), spacer (23) and screw (24);

Described excentric shaft (20) one ends are arranged to step or cubic cylinder or hexagonal prism body, center line deviation distance at excentric shaft (20) is that the e place has through hole, the axis of rotation of this through hole is parallel with the center line of excentric shaft (20), adopt screw (24) that excentric shaft (20) is fastened on the flat board (25), be set with spring collar (21) on the excentric shaft (20) successively, bearing (22), individual described bearing (22) of N and described spring collar (21), the outer race of N bearing (22) contacts with being with the no flank of tooth synchronously, between the endoporus of N bearing (22) and the excentric shaft (20) is that slight interference cooperates, when the width of N bearing is spent less than synchronization bandwidth, add a spacer (23) and make the width of the width sum of N bearing (22) and spacer (23) more than or equal to synchronous band between bearing, N gets the natural number more than or equal to 1.

3. the described double lever type force standard machines of claim 1 utilizes gravity counterweight W _BCalibration and scaling method, it is characterized in that, described double lever type force standard machines utilize gravity counterweight W _BCalibration and scaling method comprise the steps:

1) at first the double lever type force standard machines is carried out the zero balance calibration;

2) placing gravity in the upper surface of reverse frame sill is W _BGravity counterweight (12);

3) implement the zero balance calibration once more;

4) remember counterweight (10) displacement L ₁, the acting force of unit displacement then

5) for easy to use, displacement L ₁Directly represent, so the k acting force k of unit pulse with the umber of pulse of scrambler _pReplace,

k _p=W _B/ p ₁, p wherein ₁Be the mobile L of counterweight (10) ₁The umber of pulse of range encoder output.

4. the described double lever type force standard machines of claim 1 utilizes counterweight W ₁Calibration and scaling method, it is characterized in that, described double lever type force standard machines utilize counterweight W ₁Calibration and scaling method comprise the steps:

1) the utilization force cell is determined Δ (W ₁S ₁);

2) promptly add Δ (W in the change counterweight ₁S ₁) situation under carry out the calibration of zero balance;

3) remove Δ (W ₁S ₁), in the test specimen installation site that is applied in the power value force cell is installed;

4) by moving moving crossbeam (5) the reverse bridge joint of force cell and loading is touched, be in horizontality until main lever crossbeam (9);

5) read the data of force cell, to determine Δ (W ₁S ₁) the power value changes delta P that causes;

6) by moving moving crossbeam (5) the reverse frame of force cell and loading is disengaged, mobile counterweight (10) makes main lever crossbeam (9) Reversion Level state, writes down and calculate displacement Δ L ₀, record scale-up factor

Δ L ₀Can use umber of pulse p ₀Expression, scale-up factor

Also can use the power value of unit pulse

Expression,

In the formula: Δ L ₀. counterweight (10) displacement variable, Δ P. changes Δ (W ₁S ₁) the power value that causes changes.

5. according to the calibration and the scaling method of claim 4 or 5 described double lever type force standard machineses, it is characterized in that the calibration of described zero balance comprises the steps:

When 1) calibrating reverse frame is separated with moving crossbeam (5), promptly

In P=0;

2) make counterweight (10) move to position about the zero point that differential transformer (11) indication main lever crossbeam (9) is in horizontality, finely tune counterweight (10) then at null position L ₀, differential transformer this moment (11) is presented at ± and be that main lever crossbeam (9) is in horizontality within the 0.015mm scope, after this, as long as remember then to need not zero point to implement again zero balance;

3) write down counterweight (10) in main lever crossbeam (9) position at last zero point by displacement transducer.

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