CN2337526Y - Capacitance digital display callipers - Google Patents

Abstract

The utility model discloses a capacitance type digital display caliper, a straight line position X of an auxiliary scale on a main scale is changed into an angular position (that + 2 N pi) through a rack bar 11 and a gear system 21 respectively installed on the main scale and the auxiliary scale, the angular position (that + 2 N pi) is measured by a capacitance angular position measuring component 22, and the capacitance angular location measuring component 22 is isolated from a gear and a rack bar dynamic seal through a shaft sealing member 24 installed on a seal cavity 22-5. So the capacitance type digital display caliper of the utility model can reliably works in a harsh environment with pollutants, such as oil, water, dust, etc. and the utility model is especially suitable for a machine work site with cutting oil and cooling water.

Description

A kind of Capacitive Digital Display Vernier Callipers

The utility model relates to Capacitive Digital Display Vernier Callipers, particularly relates to the capacitive grid type digital display slide calliper rule that use under the mal-condition that pollutants such as oil, water and dust exist.

Digital display calliper with the making of capacitive position sensor principle, has the resolution height, advantages such as convenient reading, widely use, its major defect is that the environmental baseline of using is had relatively high expectations, because between the pole plate of capacitive position sensor be air-gap, when invaded in the air-gap dielectric coefficient when being different from the pollutants such as oil, water and dust of air capacitance will change, thereby have influence on the reliability and the accuracy of measured value.In the production scene of machine industry, there are pollutants such as cutting oil, chilled water and dust to exist unavoidably, make Capacitive Digital Display Vernier Callipers not work reliably, greatly having limited applying of Capacitive Digital Display Vernier Callipers.

In order to overcome the shortcoming of capacitive position sensor to the pollutant sensitivity, people such as Gerhard are in U.S. Patent No. 5,172, have once proposed a kind of upper and lower battery lead plate sliding contact that allows capacitive position sensor in 485, thereby do not have the way of air-gap.Theoretically, do not have air-gap between two battery lead plates, pollutant just advances not go.But the insulating protective layer of sliding contact meeting wearing and tearing electrode, unless friction force equals zero when sliding.Should not have the gap again zerofriction force then require the surface in contact of electrode very smooth smooth, the realistic difficulty of wanting like this reaches, even reached requirement when making, in use owing to expand with heat and contract with cold, reasons such as stress deformation and wearing and tearing, also can make and form the local air crack between the electrode.As long as the local air crack has been arranged, dust will be invaded to increase the weight of to wear and tear and constantly be enlarged air-gap.Therefore, the method with sliding contact is actually and can't resolve capacitive position sensor to the pollutant sensitive issue.An Demo (Andermo) reduces the sensitivity of capacitive position sensor to pollutant in the method that Chinese patent CN1114412A has proposed the thicker dielectric layer coated electrode of a kind of usefulness, this method can make the rate of change of the capacitive reactance of the sensor that causes behind the pollutant invading air crack reduce, make capacitive position sensor weaken over half to the sensitivity of pollutant, but problem fails really to solve, and still can influence the reliability and the accuracy of measured value after pollutant is invaded.Other method is a kind of absolute-type capacitive electrode caliper that people such as An Demo announces in Chinese patent CN1147084A, and its adopts the whole modes of sealing of the capacitive position sensor of slide calliper rule, prevents that pollutant from invading.Because the length of the electrode of linear position sensors on main scale must not be less than the range of slide calliper rule, the short electrode long electrode motion relatively again on the secondary chi, the sealed capacitor position transducer is exactly a long-range motive seal problem, and its difficulty is not little.People's such as An Demo method is that long and short electrode all is placed in the annular seal space, with spring leaf short moving electrode plate is pressed on the fixed electrode plate of the length that is fixed on the main scale, uses the bar that links to each other with secondary chi to pass seal bore and drive battery lead plate and on the fixed electrode plate, slide.The connecting link that this method requires auxiliary connection chi and moving electrode plate then can free bend in other directions in the rigidity that axially has of secondary chi displacement, in order to avoid being added in, excessive pressure damages capacitive position sensor on the battery lead plate, this is a requirement that almost can't realize, because but single direction has the material of strict other direction free bends of rigidity is non-existent, and axial length must have variation more or less when material bent deformation.Three embodiment use elastomeric element 172 respectively in this patent specification, bending part 672 and sheet spring 772 are connected to the moving electrode plate and are fixed between the rigid rod on the secondary chi, the introducing of these elastic components has just realized absorbing the miscellaneous part deflection and has avoided the excessive purpose of pressure, pitman shaft to rigidity but really be not guaranteed, because as long as bar reaches more than the 0.1mm in displacement perpendicular to axial direction, it will be more than 0.01mm in the axial length variations of secondary chi displacement, this length variations is with the user mode random variation, make the position of the position of secondary chi and sensor moving electrode can not keep concerning one to one and cause that measuring error, the precision of slide calliper rule just can not get guaranteeing.This patented method also exists electrode easy to wear, and the long electromagnetic interference (EMI) of detecting electrode is difficult to get rid of and complex structure is difficult for problems such as making, has also limited it and has applied.

The purpose of this utility model is exactly the deficiency that will overcome existing method, seek a kind of real effectively way and solve capacitive position sensor the pollutant sensitive issue, provide a kind of in the environment of pollutants such as oil, water and dust can reliably working, and the Capacitive Digital Display Vernier Callipers that realizes easily.

The technical solution of the utility model is: 1, on the main scale of slide calliper rule and secondary chi tooth bar is installed respectively and is comprised the gear train of a gear and rotation axis at least, gear train is meshed with tooth bar and makes the arbitrary linear position X of secondary chi on main scale, corresponding to an angular position of rotary gear shaft and the number of turns N that turns over, be X=K (θ+2N π), the constant that K is determined by the gear train structure that tooth bar and one or more gear are formed.2, on the secondary chi of above-mentioned slide calliper rule, fix a stator, have the stator electrode group of certain figure on it, a garden plate-like moving plate is installed on a rotation axis of secondary chi annular wheel system, have the rotor plate electrode group of certain figure on it.Make rotor plate electrode group and stator electrode group configuration and maintenance certain clearance formation electric capacity angular position pick up face-to-face.Be connected to the measurement display circuit by stator electrode group lead-in wire,, directly show the position X of secondary chi on main leaf by position, angle θ that measures the relative stator of moving plate and the number of turns N that turns over.3, the whole capacitor angular position pick up that will comprise stator electrode group and rotor plate electrode group is sealed in the chamber, on the rotation axis that connects electric capacity angular position pick up moving plate and gear, with shaft seals such as " O " shape rubber ring or sealing bearings, with electric capacity angular position pick up and gear, the tooth bar motive seal is isolated, make it to become waterproof, grease proofing, dustproof electric capacity angular position pick up also can become the waterproof of an one with measuring display unit and above-mentioned electric capacity angular position pick up integral sealing in case of necessity in same chamber, grease proofing, dustproof electric capacity angular position measurement assembly.In sum, the central idea of the technical program is: because to oil, water, pollutant sensitivities such as dust be the capacitive position sensor parts of slide calliper rule, rather than the mechanical parts such as blade of slide calliper rule, difficult problem for the long-range motive seal of avoiding the linear pattern capacitive position sensor, electric capacity angular position pick up with easily sealing replaces the electric capacity linear position sensors, in slide calliper rule, introduce the rack and pinion system that straight-line displacement is transformed into angular displacement for this reason, with shaft seal slide calliper rule mechanical part motive seals such as electric capacity angular position pick up and rack-and-pinion are isolated again, thereby provided a kind of at oil, can reliably working and Capacitive Digital Display Vernier Callipers that be not difficult to realize in pollutant such as water and the dust environment.

The utility model compared with prior art has following advantage: 1, be transformed into the electric capacity angular position pick up by the electric capacity linear position sensors and seal, it is little to have sealed volume, the reliable advantage of rotating shaft motive seal.The slide calliper rule of making not only can use in the environment that has pollutants such as oil, water and dust to exist, and measure also passable in the immersion liquid, as long as main scale, secondary chi and the tooth bar of slide calliper rule, gear are made of rush-resisting materials such as stainless steels, just can be in the medium-term and long-term work of water.2, simple in structure, realization, and the slide calliper rule of all size range easily can be used electric capacity angular position pick up of the same race, is convenient to the industry intensification and produces.3, electric capacity angular position pick up and measurement display circuit are sealed in an angular position measurement assembly in the chamber, as independently measuring display device, it has only a rotating shaft to stretch out outside the annular seal space by shaft seal, with its rotating shaft link the band rack pinion slide calliper rule on just become digital display calliper, also its rotating shaft directly can be installed on the rotation axis of rotatable parts of various machinery and equipment, become and measure and the instrument of indication turned position and linear position.As be contained on the screw mandrel of lathe and just can replace slide rule to become position indicator.

A specific embodiment of the present utility model is shown in Fig. 1～3, and the one-piece construction of slide calliper rule is seen Fig. 1, is equipped with to be equipped with in tooth bar 11, the secondary chi 20 and tooth bar 11 meshed gears systems, 21 (not shown)s and appearance grid angular position measurement spare 22 on main scale 10.Tooth bar 11, gear train 21 and appearance grid angular position measurement assembly 22 threes' coupled relation as shown in Figure 2.Hold grid angular position measurement assembly 22 and comprise LCD 22-1, the metering circuit plate 22-2 that integrated circuit and printed-wiring board (PWB) constitute has the stator 22-3 of round gate-shaped electrode and has the discoid moving plate 22-4 of round gate-shaped electrode.LCD 22-1, metering circuit plate 22-2 and stator 22-3 three mechanically with electric on be connected into one and annular seal space 22-5 is fixed on the secondary chi 20 together.Rotating shaft 25 is installed on the center pit of discoid moving plate 22-4, the sealing bearing 24 that rotating shaft 25 is passed on the annular seal space 22-5 is realized the rotating shaft motive seal, the lower end of rotating shaft 25 is installed in the center pit of central gear 21-1 of gear train 21, and gear train 21 also is installed on the secondary chi 20.The face-to-face concentric arrangement of circle gate electrode on circle gate electrode and the moving plate on the stator, and keep certain clearance to form a pair of electric capacity being become appearance grid angular position pick up.When secondary chi 20 slides on the guide rail of main scale 10, measurement assembly 22 and gear train 21 on the secondary chi are followed mobile, while gear train 21 and the moving plate 22-4 that links to each other with gear 21-1 are all following and are rotating, and the position, angle of the relative stator 22-3 of moving plate 22-4 is changed thereupon.Adopt existing rack-and-pinion not have the gap coupling technique, make to be equivalent to the engagement of no gap between central gear 21-1 and the tooth bar 11, guarantee that the position X of secondary chi 20 on main scale 10 is corresponding with respect to position, angle (θ+2N π) monodrome of stator 22-3 with moving plate 22-4.

The another kind of assembly structure that holds grid angular position measurement assembly 22 as shown in Figure 3, wherein LCD 22-1 position is still topmost, but rotor plate electrode 22-4 is on stator electrode 22-3, metering circuit 22-2 is in the bottom.

Claims (4)

1, a kind of Capacitive Digital Display Vernier Callipers by main scale, secondary chi, measure parts such as four of display circuit and capacitive transducers be main and constitute, is characterized in that, comprising:

On the described main scale tooth bar is installed;

Capacitive transducer is installed on the described secondary chi, measures display circuit and comprises the gear train of a gear and rotation axis at least, gear train and main scale upper rack mesh;

Described capacitive transducer is the electric capacity angular position pick up, this electric capacity angular position pick up is made up of a stator and a garden plate-like moving plate, has the electrode group on stator and the moving plate respectively, electrode group on the stator and the electrode group on the moving plate dispose face-to-face and have a gap, stator is fixed on the secondary chi, and moving plate is installed on the rotation axis of secondary chi annular wheel system:

This electric capacity angular position pick up is waterproof, grease proofing, dust seal.

2, Capacitive Digital Display Vernier Callipers according to claim 1, it is characterized in that: the waterproof of described electric capacity angular position pick up, grease proofing, dust seal are that the motive seal that is realized by the shaft seal on the annular seal space on the rotation axis of gear of moving plate is installed, and the stator and the moving plate of electric capacity angular position pick up arranged in the sealing chamber.

3, Capacitive Digital Display Vernier Callipers according to claim 1, it is characterized in that: the waterproof of described electric capacity angular position pick up, grease proofing, dust seal are that the electric capacity angular position pick up is sealed in the same chamber together with measuring display circuit, make the electric capacity angular position pick up and measure display circuit to be combined into a waterproof, grease proofing, dustproof electric capacity angular position measurement assembly.

4, Capacitive Digital Display Vernier Callipers according to claim 1, it is characterized in that: the described rack and pinion system that is installed on main scale and the secondary chi, the angular position of rotation θ that secondary chi is transformed into the moving plate on the gear at the position X on the main scale measures with the number of turns N that turns over, be X=K (θ+2N π), K is that the pairing smallest angular resolution θ mim of minimum length resolution Xmim that K satisfies slide calliper rule is that described electric capacity angular position pick up can resolved detection come out by the constant of rack and pinion system architecture decision.

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