CN204855330U - Coal pick three -dimensional cut force measuring device - Google Patents

Abstract

The utility model relates to a coal pick three -dimensional cut force measuring device, including the pick, the toothholder, three -dimensional force transducer and sensing system signal processor, the pick includes pick head and pick body, the pick body is installed in the toothholder mounting hole, three -dimensional force transducer establishes at the contact surface of pick head with the toothholder, three -dimensional force transducer includes X direction electric capacity unique tuple and Y direction electric capacity unique tuple, X direction electric capacity unique tuple and Y direction electric capacity unique tuple all include electric capacity unit module, electric capacity unit module is the comb dentate structure who comprises the strip electric capacity unit more than two. Through obtaining the pick at the three -dimensional force information of coal cut in -process, for quantitative evaluation coal cut characteristic, in -depth study coal cut mechanism, rationally select and use coal -winning machine and pick etc. To provide important foundation.

Description

Coal pick three-dimensional clipping force measurement mechanism

Technical field

The utility model belongs to Coal Mechanical technical field, relates to a kind of pick device, is specifically related to a kind of coal pick three-dimensional clipping force measurement mechanism.

Background technology

The model of choose reasonable coalcutter and pick type, have certain influence to the work efficiency of coalcutter and the life-span of pick.The height of coalcutter real work efficiency and the quality of working effect thereof are the results of many factors combined action, as the structure of coal mining machine roller, the material of pick, shape, size and arrangement thereof and setting angle, the cut degree of depth, the haulage speed of motor, the physical-mechanical properties etc. in coal seam.Because the coal properties of different mine and different coal is all different, and the fragmentation of coal in cutting course is random, and the power that therefore coalcutter is suffered in cutting course is also different.Measure clipping force accurately, a large amount of force informations of pick in coal cutting process can be obtained, thus provide important evidence for quantitative evaluation coal cutting characteristic, further investigation coal cutting mechanism, choose reasonable and use coalcutter and pick etc.

There is two large problems in some sensor measuring the coal cutting power apparatus of single pick or standard testing cutter: can not survey three-dimensional cut component, majority only can survey main clipping force, can survey main clipping force and radial force individually; Poor dynamic, data distortion is larger.Coal cutting power is the stochastic and dynamic power that power amplitude variation moves greatly, frequency is higher, must measure by good, highly sensitive by dynamic property, that component cross jamming is little three-dimensional force transducer, obtains the cut component of monodentate thus.

Summary of the invention

In order to overcome the deficiencies in the prior art, the utility model provides a kind of coal pick three-dimensional clipping force measurement mechanism, use this measurement mechanism, can obtain pick in cut coal process by force information, for further investigation coal cutting mechanism, quantitative evaluation coal cutting characteristic, choose reasonable and use coalcutter, optimal design coalcutter and pick provide foundation, and then improve production efficiency and the economic benefit of enterprise.

The technical solution of the utility model is: a kind of coal pick three-dimensional clipping force measurement mechanism, comprise pick, toothholder, three-dimensional force transducer and sensor-based system signal processor, described pick comprises cutting pick head and pick body, pick body is installed in toothholder mounting hole, described three-dimensional force transducer is located at the surface of contact of cutting pick head and toothholder, the lower pcb board of sensor and toothholder are fixed, upper pcb board contacts with cutting pick head but does not fix, described three-dimensional force transducer comprises X-direction capacitor cell group and Y-direction capacitor cell group, described X-direction capacitor cell group and Y-direction capacitor cell group include capacitor cell module, the comb teeth-shaped structure that described capacitor cell module is made up of plural strip capacitor cell, each strip capacitor cell comprises the drive electrode of top crown and the induction electrode of bottom crown, described capacitor cell module comprises by two or more width a ₀length b ₀strip capacitor cell composition the first strip capacitor cell group and two or more width ka ₀length b ₀strip capacitor cell composition the second strip capacitor cell group.

Coal pick three-dimensional clipping force measurement mechanism also comprises bearing, and bearing is installed in toothholder mounting hole, and pick body is installed on bearing center.The drive electrode of described each strip capacitor cell is identical with induction electrode width, and the length of drive electrode is greater than induction electrode length, and drive electrode length two ends are reserved left poor position δ respectively _leftwith right poor position δ _right, b _{0 drives}=b _{0 sense}+ δ _right+ δ _left, wherein, b _{0 drives}for the drive electrode length of strip capacitor cell, b _{0 sense}for the induction electrode length of strip capacitor cell.Described poor position δ _left=δ _right, and wherein d ₀for strip capacitor cell dielectric thickness, G is the modulus of rigidity of elastic medium, τ _maxfor maximum stress value.The lead-in wire that described comb teeth-shaped structure comprises more than 20 strip capacitor cells, connects one to one with strip capacitor cell, is provided with electrode separation a between adjacent two strip capacitor cells _δ.Described parallel-plate area S=M (a ₀+ 2a _δ+ ka ₀) b ₀/ 2, wherein, M is strip capacitor cell quantity, b ₀for the length of strip capacitor cell, a ₀the width of strip capacitor cell.The strip capacitor cell lead-in wire of described first strip capacitor cell group and the second strip capacitor cell group is by parallel connection or be independently connected to sensor-based system signal processor.The width of described strip capacitor cell wherein, d ₀for dielectric thickness, E is the Young modulus of elastic medium, and G is the modulus of rigidity of elastic medium.Described first strip capacitor cell group and be respectively equipped with intermediate translator between the second strip capacitor cell group and sensor-based system signal processor, intermediate translator is for arranging voltage to electric capacity or frequency to the transmission coefficient of electric capacity.Described sensor system signals processor comprises multiple signals high speed commutation circuit, A/D translation circuit and control circuit, described high speed commutation circuit comprises three grades of commutation circuits, the output of previous stage commutation circuit is the input signal of next stage commutation circuit, and afterbody commutation circuit sends into control circuit through A/D translation circuit.

The utility model has following good effect: coal pick three-dimensional clipping force measurement mechanism of the present utility model can measure the three-dimensional of pick in cut coal process by force information, measure clipping force accurately, the a large amount of force informations of pick in coal cutting process can be obtained, thus provide important evidence for quantitative evaluation coal cutting characteristic, further investigation coal cutting mechanism, choose reasonable and use coalcutter and pick etc.

Accompanying drawing explanation

Fig. 1 is strip capacitor cell and the coordinate system thereof of embodiment of the present utility model.

Fig. 2 is the strip capacitor cell schematic diagram of embodiment of the present utility model.

Fig. 3 is the strip capacitor cell dextrad skew schematic diagram of embodiment of the present utility model.

Fig. 4 is the strip capacitor cell left-hand skew schematic diagram of embodiment of the present utility model.

Fig. 5 is the width of embodiment of the present utility model is a ₀and ka ₀electric capacity to stressed deflection graph.

Fig. 6 is the parallel-plate three-dimensional force pressure sensor structure figure of embodiment of the present utility model.

Fig. 7 is the signal schematic representation that the cell capacitance of embodiment of the present utility model is right.

Fig. 8 is the structural drawing of the utility model embodiment pick.

Fig. 9 is the part sectioned view of the utility model embodiment pick.

Wherein, 1 pick, 101 cutting pick head, 102 pick bodies, 2 toothholders, 3 bearings.

Embodiment

Contrast accompanying drawing below, by the description to embodiment, embodiment of the present utility model is as the effect of the mutual alignment between the shape of involved each component, structure, each several part and annexation, each several part and principle of work, manufacturing process and operation using method etc., be described in further detail, have more complete, accurate and deep understanding to help those skilled in the art to inventive concept of the present utility model, technical scheme.

In the experiment of coal petrography cut, cut experimental provision comprises main motion system, supplementary motion system and pick 1, under the dynamic action of kinematic system, pick 1 coal petrography cutting, as shown in FIG. 8 and 9, for the structural representation of the utility model pick 1, pick 1 device comprises pick 1, toothholder 2 and bearing 3, pick 1 comprises cutting pick head 101 and pick body 102, toothholder 2 has mounting hole, bearing 3 is installed in the mounting hole of toothholder 2, and pick body 102 is installed on the center of bearing 3, and pick 1 relatively toothholder 2 is rotated.Be provided with bearing 3 structure between pick body 102 of the present utility model and toothholder 2 endoporus, between pick 1 and toothholder 2, form rolling friction, avoid in prior art, forming pick 1 rotation because of sliding friction and have some setbacks, and then produce the problems such as wearing and tearing inequality, partial wear.

As Fig. 8, three-dimensional force transducer of the present utility model is located at the surface that cutting pick head 101 connects with toothholder 2, and the face of pcb board up and down of sensor contacts with toothholder 2 with cutting pick head 101 respectively, and lower pcb board and toothholder 2 are fixed, and upper pcb board contacts with pick 1 but do not fix.Sensor can measure three direction x, y, the power of z, each signalling channel all has independently signal acquisition circuit, the signal of each passage is independent of each other mutually, sensor-based system signal processor mainly comprises avr single-chip minimum system, signal condition amplification module, A/D modular converter, data memory module and power module, and sample frequency is not less than 100Hz.Each channel signal, by after signal conditioning circuit and amplifying circuit process, through signal conversion module access avr single-chip microcomputer, and carries out storage operation to data.Avr single-chip microcomputer is connected to data acquisition/serial communication change-over switch and SD card module for reading and writing.This device supports FAT file system, after single-chip data stores, the pattern with FAT file system function with the exchanges data of host computer, namely SD is stuck in the single-chip microcomputer course of work and can obtains data, then direct SD cartoon is crossed USB interface and host computer carry out file reading, copy and the file operation such as to store.The self-powered module of this device, can when normally working without when external power supply.The direct supply of supply voltage input conditioning circuit to input regulates.Telecommunication circuit is used for the transmission of digital signal and realizes embedded measurement device and the direct data interaction of host computer.

The measuring principle of three-dimensional force transducer of the present utility model is below described in detail in detail: if Fig. 4-6 is the electrode plate structure figure of the utility model pressure transducer, the utility model sensor comprises X-direction capacitor cell group and Y-direction capacitor cell group, described X-direction capacitor cell group and Y-direction capacitor cell group include capacitor cell module, described capacitor cell module adopts the comb teeth-shaped structure be made up of plural strip capacitor cell, and each strip capacitor cell comprises the drive electrode of top crown and the induction electrode of bottom crown.Described capacitor cell module comprises by two or more width a ₀length b ₀first strip capacitor cell group of strip capacitor cell composition and two or more width ka ₀length b ₀second strip capacitor cell group of strip capacitor cell composition.The drive electrode of described each strip capacitor cell is identical with induction electrode width, and the length of drive electrode is greater than induction electrode length, and drive electrode length two ends are reserved left poor position δ respectively _leftwith right poor position δ _right, b _{0 drives}=b _{0 sense}+ δ _right+ δ _left, wherein, b _{0 drives}for the drive electrode length of strip capacitor cell, b _{0 sense}for the induction electrode length of strip capacitor cell.Described poor position δ _left=δ _right, and wherein d ₀for dielectric thickness, G is the modulus of rigidity of elastic medium, τ _maxfor maximum stress value.The lead-in wire that described comb teeth-shaped structure comprises more than 20 strip capacitor cells, connects one to one with strip capacitor cell, is provided with electrode separation a between adjacent two strip capacitor cells _δ.Described parallel-plate area S=M (a ₀+ 2a _δ+ ka ₀) b ₀/ 2, wherein, M is strip capacitor cell quantity, b ₀for the length of strip capacitor cell, a ₀the width of strip capacitor cell.The strip capacitor cell lead-in wire of described first strip capacitor cell group and the second strip capacitor cell group is by parallel connection or be independently connected to sensor-based system signal processor.The width of described strip capacitor cell wherein, d ₀for dielectric thickness, E is the Young modulus of elastic medium, and G is the modulus of rigidity of elastic medium.Described first strip capacitor cell group and be provided with intermediate translator between the second strip capacitor cell group and sensor-based system signal processor, intermediate translator is for arranging voltage to electric capacity or frequency to the transmission coefficient of electric capacity.

1, the conversion characteristic of strip capacitor cell

(1) pumping signal and coordinate system

Strip capacitor cell is placed in the rectangular coordinate system shown in Fig. 1, pole plate plane length b ₀, width a ₀, dielectric thickness d ₀.Three-dimensional simulation puts on the outside surface of capacitor plate, and the contact acting force of generation has Fx, Fy and Fz tri-durection components, and the action direction of Fx and Fy is along X-axis and Y-axis, and the action direction of Fz along OZ axle namely direction, normal direction and tangential stress are a kind of stress tensor, can output capacitance respond between the lead-in wire of electrode; Normal stress σ _n=Fn/A, wherein A=a ₀b ₀for pole plate normal direction stress surface, Fn=Fz is normal component; Both side surface produces paired tangential stress τ _x=Fx/A, τ _y=Fy/A.

According to the Hooke's law in Elasticity, σ _nand τ _x, τ _yelastic body all will be made to produce corresponding distortion.Wherein,

${\mathrm{\σ}}_n=E\·{\mathrm{\ϵ}}_n=E\·{\mathrm{\δ}}_n{\mathrm{/d}}_0=\frac{F_n}{A}---\left(1\right)$

$\±{\mathrm{\τ}}_x=\±{\mathrm{\γ}}_x\·\mathrm{G=}\±G\·{\mathrm{\δ}}_x/d_0=\±\frac{F_x}{A}---\left(2\right)$

$\±{\mathrm{\τ}}_y=\±{\mathrm{\γ}}_y\·\mathrm{G=}\±G\·{\mathrm{\δ}}_y/d_0=\±\frac{F_y}{A}---\left(3\right)$

In formula, E is the Young modulus (unit: GN/m of elastic medium ²), G is the modulus of rigidity (unit: GN/m of elastic medium ²), δ n is the Normal Displacement (unit: μm) of elastic medium, and δ x and δ y is the relative dislocation (unit: μm) of the upper and lower two-plate of capacitor, and its sign is pointed to by coordinate axis and determined.

(2) capacitance equation and input-output characteristic thereof

The initial capacitance of rectangular parallel plate capacitor is:

$C_0=\frac{{\mathrm{\ϵ}}_0\·{\mathrm{\ϵ}}_r\·a_0\·b_0}{d_0}---\left(4\right)$

In formula, ε ₀vacuum medium electric constant is 8.85PF/m, ε _r=2.5 is dielectric relative dielectric constant.D ₀by σ _nexcitation produce relative deformation ε _n=δ _n/ d ₀=σ _n/ E, substitutes into (4) and obtains input-output characteristic

$C_n={\mathrm{\ϵ}}_0\·{\mathrm{\ϵ}}_r\frac{a_0\·b_0}{d_0(1-{\mathrm{\ϵ}}_n)}={\mathrm{\ϵ}}_0\·{\mathrm{\ϵ}}_r\frac{a_0\·b_0}{d_0(1-\frac{F_n}{AE})}---\left(5\right)$

(3) linearity under normal stress effect and sensitivity

A, the normal direction linearity

F in (5) formula _nin the denominator, therefore C _n=f (F _n) relation be nonlinear, because of conversion range in maximal value σ _nmaxcompared with dielectric resilient constant E, ε _na very little amount, i.e. ε in denominator _n<<1, (5) are omitted the higher-order shear deformation of more than quadratic power by series expansion, and (5) formula can be reduced to:

$C_n=C_0(1+\mathrm{\&epsiv;})=C_0(1+\frac{F_n}{A\&CenterDot;E})---\left(6\right)$

Visible at C _nwith F _nconversion characteristic in the maximum relative error of the normal direction linearity close to zero.

B, sensitivity

By the definition of normal direction sensitivity

Can linear sensitivity be obtained by (6) formula,

$S_{n1}=C_0/AE={\mathrm{\&epsiv;}}_0{\mathrm{\&epsiv;}}_r/d_{0}E---\left(7\right)$

By (5) formula then

$S_{n2}=\frac{{\mathrm{dC}}_n}{{\mathrm{dF}}_n}=C_0\&CenterDot;\frac{1}{1-2\mathrm{\&epsiv;}}=C_0\&CenterDot;\frac{1}{1-2\frac{F_n}{A\&CenterDot;E}}---\left(8\right)$

S _n2with F _nand become, F _nlarger, S _n2larger, in mild nonlinear in whole conversion characteristic.

(4) tangential stress τ _xand τ _ycapacitance variations under excitation

Tangential stress τ _xand τ _ydo not change the physical dimension parameter b of pole plate ₀and a ₀, to dielectric thickness d ₀also do not have an impact.But τ _xand τ _ychange the space structure of strip capacitor cell, between the upper bottom crown faced by forward, there occurs dislocation skew.Now for OX direction, pole plate is at τ _xdislocation skew δ under effect _x.

Work as τ in fig. 2 _xwhen being zero, a _{on 0}=a _{0 time}just right, free area A between substrate _τ=a ₀b ₀; In figure 3, at τ _xunder the effect of dextrad, top crown creates dislocation skew δ to the right relative to bottom crown _x, thus make the useful area A between bottom crown when calculating electric capacity _τ=(a ₀-δ _x) b ₀; In Fig. 4, work as τ _xduring for left-hand, dislocation skew δ _xthen left, A _τ=(a ₀-δ _x) b ₀, τ _xwhen left-hand and dextrad, the reduction of useful area is identical, and consequent electric capacity is:

$C_{\mathrm{\&tau;}x}=\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;(a_0-{\mathrm{\&delta;}}_x)\&CenterDot;b_0}{d_0}---\left(9\right)$

According to shearing Hooke's law

τ _x＝γ _x·G＝G·δ _x/d ₀(10)

(10) are substituted into (9) can obtain

$C_{\mathrm{\&tau;}x}=C_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;{\mathrm{\&delta;}}_x\&CenterDot;b_0}{d_0}=C_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;b_0{\mathrm{\&tau;}}_x}{G}=C_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r{F}_x}{{\mathrm{Ga}}_0}---\left(11\right)$

(11) formula is the input-output characteristics under shearing stress, C _τwith τ _xlinear.

And its sensitivity

$S_{\mathrm{\&tau;}x}=\frac{{\mathrm{dC}}_{\mathrm{\&tau;}x}}{{\mathrm{dF}}_x}=\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r}{{\mathrm{Ga}}_0}---\left(12\right)$

The similar analysis in formula (9)-(12) is suitable for and τ equally _ywith C _{τ y}characteristic and technical indicator, the only long limit b of strip capacitor cell in formula ₀oX direction of principal axis should be arranged at, and its minor face a ₀then in OY direction.

2, contact parallel plate capacitor design

(1) planar design of parallel plate capacitor

The original index normal direction Max.contact stress σ of setting _nmaxfor 200Kpa, if the stressed A of normal direction is square 10 × 10mm ², then maximum normal force F _zmaxfor σ _nmaxa=20N.Tangential Max.contact stress τ _maxfor 70Kp, the distribution of force face of tangential stress is 10 × 10mm ², then maximum tangential force component F _xmax=F _ymax=τ _maxa=7N.

Strip capacitor cell constructive variations shown in Fig. 3 and Fig. 4, only illustrates that electric capacity exports and tangential stress ± τ _xthe relation of input, capacitance increase is all negative, and therefore this initial capacitance structure is not suitable for as right ± τ _xobtain the response increasing and decreasing electric capacity.The utility model adjusts the initial configuration of bottom crown on strip capacitor cell for this reason, and width is a ₀and ka ₀strip capacitor cell form a pair capacitor cell to (C _lwith C _r), specifically as shown in Figure 5.

In Fig. 5, capacitor cell C _land C _relectrode size b ₀, d ₀all identical, width one is a ₀, one is ka ₀, wherein k is constant, is preferably greater than the integer of 1.Work as τ _xwhen=0, C _l=C ₀, C _r=kC ₀, on this basis as at F _xδ is produced under excitation _xmistake skew, offset effect as shown in figure 3 or 4 will be formed.

$C_L=\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;b_0\&CenterDot;(a_0-{\mathrm{\&delta;}}_x)}{d_0}=C_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;b_0{\mathrm{\&tau;}}_x}{G}=C_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r{F}_x}{{\mathrm{Ga}}_0}---\left(13\right)$

$C_R=\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;b_0\&CenterDot;({\mathrm{Ka}}_0-{\mathrm{\&delta;}}_x)}{d_0}={\mathrm{kC}}_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r\&CenterDot;b_0{\mathrm{\&tau;}}_x}{G}={\mathrm{kC}}_0-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r{F}_x}{{\mathrm{Ga}}_0}---\left(14\right)$

C _land C _rcapacitor cell is at same τ _xδ will be produced _xwith Δ C _τresponse.

Thus, formula (11) can be revised as

$C_{\mathrm{\&tau;}x}=C_{\mathrm{\&tau;}0}-\frac{{\mathrm{\&epsiv;}}_0\&CenterDot;{\mathrm{\&epsiv;}}_r}{{\mathrm{Ga}}_0}{F}_x$

In formula, for initial capacitance when shearing stress is zero, above formula is shearing stress input-output characteristic, C _{τ x}with F _xlinear relationship, and its sensitivity

Electrode plane see Fig. 6 is arranged, at a 10 × 10mm ²substrate center do cross separate, form four quadrants, upper right first quartile I, upper left second quadrant II, lower-left third quadrant III, bottom right fourth quadrant IV, wherein I, III quadrant is to τ _xmake the capacitor cell combination of response, and II, IV quadrant is to τ _ymake the capacitor cell combination of response.Object-line is 10 × 10mm ²pcb board four edge lines, hachure part represents the outer mode cross section of wax-loss casting process.Using the position of induction electrode in lower floor's PCB substrate as reference, then the layout of drive electrode in the PCB substrate of upper strata should with PCB substrate edge line for benchmark.In figure, four dashed rectangle are the benchmark of induction electrode on bottom crown, put they and geometry datum line differential apart from being δ ₀(0.1mm).

Capacitor cell module adopts comb structure, and capacitor cell module adopts the comb teeth-shaped structure be made up of plural strip capacitor cell, and each strip capacitor cell comprises the drive electrode of top crown and the induction electrode of bottom crown.By formula (12) a ₀less, the sensitivity of tangential stress response is larger, therefore single capacitor cell is strip.If every root strip capacitor cell is wide is a ₀, the groove width between two strip electric capacity is a _δ, then the pitch of every root strip capacitor cell is ka ₀+ a ₀+ 2a _δ.In order to make full use of the plane space of square substrate, M (ka ₀+ a ₀+ 2a _δ) b ₀/ 2 ≈ 1 square substrate areas, M is strip electric capacity quantity, then have M (ka ₀+ a ₀+ 2a _δ)=20mm, in formula, groove width a _δunsuitable excessive, otherwise be unfavorable for using the effective plane space on substrate, also unsuitable too small, the constraint of wax-loss casting process is subject to.For making normal direction sensitivity S _nwith tangential sensitivity S _τequal, by formula (7) and (12), make a ₀g=d ₀e, works as d ₀when=0.1mm, k=1.5, thus M can be obtained.

In order to realize τ _xand τ _ybetween tangential response mutually do not have an impact, the drive electrode length two ends reserved difference position δ of strip capacitor cell ₀, therefore b _{0 drives}=b _{0 end}+ 2 δ ₀, wherein at b _{0 drives}two ends length reserved difference potential theory should ensure its calculated value is ${10}^{-5}\&times;\frac{70\&times;{10}^3}{2.4\&times;{10}^6}=2.9\&times;{10}^{-8}m={10}^{-2}um<<1um,$ Therefore should b be ensured in technique _{0 drives}-b _{0 end}>=0.01mm.

In order to realize τ _xand τ _ydo not produce any impact to the response of normal direction electric capacity, width is a ₀and ka ₀strip capacitor cell form a pair capacitor cell to (C _lwith C _r) carry out publicity reckoning elimination impact each other.Ensure τ _xproduce τ at I, III quadrant capacitor cell _xelectric capacity response, then produce τ at II, IV quadrant capacitor cell _yelectric capacity response, to ensure that capacitor cell in four quadrants is at τ _xand τ _ytwo groups of differential capacitors pair can be produced under tangential excitation.Like this when computing method exports response to electric capacity, ensure τ _xand τ _yany impact is not produced on the response of normal direction electric capacity.

(2) calculating of normal stress and tangential force

If width is a in Fig. 5 ₀strip capacitor cell be subject to tangential force τ _x, produce a tangential displacement d _xafter output capacitance value be C ₁, width is ka ₀strip capacitor cell be subject to tangential force τ _x, produce a tangential displacement d _xafter output capacitance value be C ₂, then have:

$C_1=\frac{\mathrm{\&epsiv;}(a_0-d_x)b_0}{d_n}=\frac{{\mathrm{\&epsiv;a}}_0{b}_0}{d_n}-\frac{{\mathrm{\&epsiv;b}}_0{d}_x}{d_n}---\left(15\right)$

$C_2=\frac{\mathrm{\&epsiv;}({\mathrm{ka}}_0-d_x)b_0}{d_n}=\frac{{\mathrm{\&epsiv;ka}}_0{b}_0}{d_n}-\frac{{\mathrm{\&epsiv;b}}_0{d}_x}{d_n}---\left(16\right)$

Obtained by (15)-(16):

$C_1-C_2=\frac{{\mathrm{\&epsiv;a}}_0{b}_0}{d_n}-\frac{{\mathrm{\&epsiv;ka}}_0{b}_0}{d_n}$ Calculate:

$d_n=\frac{{\mathrm{\&epsiv;a}}_0{b}_0(1-k)}{C_1-C_2}---\left(17\right)$

Obtained by (15) * k-(16):

${\mathrm{kC}}_1-C_2=\frac{{\mathrm{\&epsiv;d}}_x{b}_0}{d_n}-\frac{{\mathrm{\&epsiv;kd}}_x{b}_0}{d_n}=\frac{{\mathrm{\&epsiv;d}}_x{b}_0(1-k)}{d_n},$ (17) are substituted into above formula, can obtain:

$d_x=\frac{a_0({\mathrm{kC}}_1-C_2)}{C_1-C_2}---\left(18\right)$

According to $d_n=d_0-\mathrm{\&Delta;}d=d_0(1-\frac{F_h}{E\&CenterDot;S_0})$

Known: $F_n=\frac{(d_n-d_0)E\&CenterDot;S_0}{d_0}$

By $\frac{d_x}{d_0}=\mathrm{\&gamma;}=\frac{\mathrm{\&tau;}}{G}=\frac{F_{\mathrm{\&tau;}}}{G\&CenterDot;S_0},$ So $F_{\mathrm{\&tau;}x}=\frac{{\mathrm{GS}}_0{d}_x}{d_0}.$

In above formula, no matter be normal direction excitation F _nor tangentially encourage F _yall not to O _τhave an impact.Namely automatically σ is eliminated _nand τ _yto τ _xthe coupling of total output or interference comprise at signal because every in the computing of subtracting each other, equivalent and the capacitance variations with symbol are eliminated all automatically.And F _yand F _xto σ _ninterference by upper electrode at b ₀direction increases geometrical length 2 δ ₀eliminate.In like manner F can be obtained _{τ y}.

(4) main material selection and characterisitic parameter thereof

The pole plate of comb teeth-shaped plane-parallel capacitor is apart from d ₀=0.1mm, upper and lower base plate inner space, except copper foil electrode, is PDMS (dimethyl silicone polymer) the superlastic insulating medium with lost wax process filling.Its machinery and physical characteristics parameter are Young modulus E=6.2MPa, and its shear modulus is G=4.1MPa, relative DIELECTRIC CONSTANT ε during dielectric polorization _γ=2.5.Because E and G of medium is much smaller than the elastic modulus E of copper _copper=103GPa, therefore the distortion of capacitor internal medium under stress state is much larger than the distortion of pole plate.

(5) contact conductor design

Be that drive electrode or induction electrode all need to have extension line, consider that each drive electrode is all ground connection in signal level, therefore four groups of drive electrodes only need share same extension line.The induction electrode of four the first strip capacitor cell groups and the second strip capacitor cell group then needs with respective independently extension line, and draw from the side of planar package so whole capacitance component has at least 5 pins, four induction electrodes refer to that X-direction width is a ₀induction electrode and width be ka ₀induction electrode, and Y-direction width is a ₀induction electrode and width be ka ₀induction electrode so that whole assembly top and bottom outside surface can contact with measuring object easily.The utility model, under the support of new material and new technology, completes the design of a kind of novel three-dimensional power sensitization capacitance combination, at 10 × 10mm ²stress surface on, be no matter normal direction or tangential, all can transmit stress more uniformly to medium.In literary composition, four cell capacitance are two to combination distribution.In the contact of non-coplanar force and sensor surface, external force only has 1, and electric capacity response but has 4, and whole battery lead plate, all to asking Fn to contribute, simultaneously by two pairs of capacitor combinations composition systems, can obtain F again _xand F _yinformation, thus complete description three-dimensional force.

The utility model pick three axis force measurement mechanism can measure and rotate cut operating mode under the different coal petrography of single pick 1 cut by force signal, there is higher sample frequency, decrease the loss of signal and the impact of undesired signal.Embedded pick tooth spiral turns that cut device for measuring force overcomes conventional apparatus non intelligentization, site of deployment is difficult to regulate and inconvenience and the shortcoming such as host computer communicates.For further investigation coal cutting mechanism, quantitative evaluation coal cutting characteristic, choose reasonable and use coalcutter, optimal design coalcutter and pick 1 provide foundation.By reference to the accompanying drawings the utility model is exemplarily described above; obvious the utility model specific implementation is not subject to the restrictions described above; as long as have employed the improvement of the various unsubstantialities that method of the present utility model is conceived and technical scheme is carried out; or design of the present utility model and technical scheme directly applied to other occasion, all within protection domain of the present utility model without to improve.The protection domain that protection domain of the present utility model should limit with claims is as the criterion.

Claims (9)

1. a coal pick three-dimensional clipping force measurement mechanism, it is characterized in that, comprise pick, toothholder, three-dimensional force transducer and sensor-based system signal processor, described pick comprises cutting pick head and pick body, pick body is installed in toothholder mounting hole, described three-dimensional force transducer is located at the surface of contact of cutting pick head and toothholder, the lower pcb board of three-dimensional force transducer and toothholder are fixed, upper pcb board contacts with cutting pick head but does not fix, described three-dimensional force transducer comprises X-direction capacitor cell group and Y-direction capacitor cell group, described X-direction capacitor cell group and Y-direction capacitor cell group include capacitor cell module, the comb teeth-shaped structure that described capacitor cell module is made up of plural strip capacitor cell, each strip capacitor cell comprises the drive electrode of top crown and the induction electrode of bottom crown, described capacitor cell module comprises by two or more width a ₀length b ₀strip capacitor cell composition the first strip capacitor cell group and two or more width ka ₀length b ₀strip capacitor cell composition the second strip capacitor cell group.

2. coal pick three-dimensional clipping force measurement mechanism according to claim 1, it is characterized in that, described measurement mechanism also comprises bearing, and bearing is installed in toothholder mounting hole, and pick body is installed on bearing center.

3. coal pick three-dimensional clipping force measurement mechanism according to claim 1, it is characterized in that, the drive electrode of described each strip capacitor cell is identical with induction electrode width, and the length of drive electrode is greater than induction electrode length, and drive electrode length two ends are reserved left poor position δ respectively _leftwith right poor position δ _right, b _{0 drives}=b _{0 sense}+ δ _right+ δ _left, wherein, b _{0 drives}for the drive electrode length of strip capacitor cell, b _{0 sense}for the induction electrode length of strip capacitor cell.

4. coal pick three-dimensional clipping force measurement mechanism according to claim 3, is characterized in that, described poor position δ _left=δ _right, and wherein d ₀for strip capacitor cell dielectric thickness, G is the modulus of rigidity of elastic medium, τ _maxfor maximum stress value.

5. coal pick three-dimensional clipping force measurement mechanism according to claim 1, it is characterized in that, the lead-in wire that described comb teeth-shaped structure comprises more than 20 strip capacitor cells, connects one to one with strip capacitor cell, is provided with electrode separation a between adjacent two strip capacitor cells _δ.

6. coal pick three-dimensional clipping force measurement mechanism according to claim 5, is characterized in that, described parallel-plate area S=M (a ₀+ 2a _δ+ ka ₀) b ₀/ 2, wherein, M is strip capacitor cell quantity, b ₀for the length of strip capacitor cell, a ₀the width of strip capacitor cell.

7. coal pick three-dimensional clipping force measurement mechanism according to claim 2, it is characterized in that, the strip capacitor cell lead-in wire of described first strip capacitor cell group and the second strip capacitor cell group is by parallel way or be independently connected to sensor-based system signal processor.

8. coal pick three-dimensional clipping force measurement mechanism according to claim 2, is characterized in that, the width of described strip capacitor cell wherein, d ₀for dielectric thickness, E is the Young modulus of elastic medium, and G is the modulus of rigidity of elastic medium.

9. coal pick three-dimensional clipping force measurement mechanism according to claim 2, it is characterized in that, described first strip capacitor cell group and be respectively equipped with intermediate translator between the second strip capacitor cell group and sensor-based system signal processor, intermediate translator is for arranging voltage to electric capacity or frequency to the transmission coefficient of electric capacity.