CN104111026B - Variable orifice calipers based on capacitor with multiple electrode plates sensor - Google Patents

Abstract

The invention discloses a kind of variable orifice calipers based on capacitor with multiple electrode plates sensor.The capacitor sensor structures using fixed electrode in production application at present and scientific research field, its gauge head is only applicable to the measurement of constant aperture, and can not carry out large range measuring aperture more.The present invention includes battery lead plate, slide block, driving shaft, housing, driven wheel of differential and drive bevel gear；The top of housing offers multiple chute；The inside center of housing is provided with driven shaft；Driven wheel of differential is bearing on driven shaft；Drive bevel gear is fixed with driving shaft；Driving shaft is bearing on housing by bearing, and one end is stretched out outside housing；Driven wheel of differential engages with drive bevel gear；Being equipped with slide block in each chute of housing, the screw thread of every piece of slider bottom all flat threads with driven wheel of differential top engage；The medial wall of every piece of slide block is fixed with an electrode plate；All battery lead plates are uniformly distributed along the circumference.The present invention can realize the accurate measurement in variable orifice footpath, ensures certainty of measurement in relatively large journey.

Description

Variable orifice calipers based on capacitor with multiple electrode plates sensor

Technical field

The invention belongs to fine measuring instrument technical field, relate to aperture measurement device, be specifically related to a kind of variable orifice calipers based on capacitor with multiple electrode plates sensor.

Background technology

Along with the fast development in the fields such as machinery, Aero-Space, military affairs, it is the current scientific and technological major trend with industrial development that minute sized processing and measurement propose the highest requirement, high accuracy and miniaturization.

Inside diameter measurement is one of important content of pore geometry measurement technique, and the method for inside diameter measurement has a lot, but owing to being affected by the restriction of bulk and measurement contact force, all there are some defects.Capacitance type sensor is widely used in the measurement of hole diameter, and its advantage mainly has: (1) is possible not only to measure small through hole and blind hole, and the size and dimension error of arbitrary section in aperture can be measured；(2), after coordinating different adaptors, the micro hole of all directions can be measured；(3) system accuracy is measured high, with low cost, simple to operation.But the capacitor sensor structures using fixed electrodes at present production application and scientific research field more, its gauge head is only applicable to the measurement of a certain constant aperture, and large range measuring aperture can not be carried out, thus cause the range of application of capacitance sensor to be restricted, measure different apertures and be accomplished by the transducer probe assembly of different size.

Summary of the invention

It is an object of the invention to for the deficiencies in the prior art, provide a kind of variable orifice calipers based on capacitor with multiple electrode plates sensor, this device can realize the accurate measurement in variable orifice footpath, it is effectively improved the efficiency of measurement, in relatively large journey, ensure certainty of measurement, reduce the input cost of measuring instrument simultaneously.

The present invention includes battery lead plate, slide block, driving shaft, housing, driven wheel of differential and drive bevel gear；The top of described housing offers the multiple chutes being circumferentially radially arranged；The bottom opening of described chute is in the top inner wall of housing；The inside center of described housing is provided with integrated driven shaft；Described driven wheel of differential is bearing on driven shaft by bearing；Described drive bevel gear is fixed with driving shaft；Described driving shaft is bearing on housing by bearing, and one end is stretched out outside housing；Described driven wheel of differential engages with drive bevel gear.Being equipped with slide block in each chute of described housing, the screw thread of every piece of slider bottom all flat threads with driven wheel of differential top engage；The medial wall of every piece of slide block is fixed with an electrode plate；Described battery lead plate is cylindricality, and cross section is ring-type in fan；All battery lead plates are uniformly distributed along the circumference.

The bottom of described housing removably connects with end cap.

Angle between described driven wheel of differential and drive bevel gear axis is 90 °.

The central angle that described battery lead plate is corresponding is 30～70 °.

Described battery lead plate place circle diameter adjustable extent is 10～25mm.

Beneficial effects of the present invention:

1, detecting electrode is the most adjustable, thus realizes the accurate measurement in multiple aperture, the shoulder hole being more or less the same including through hole, blind hole, micro hole and aperture.

2, use capacitance sensor measuring principle, be effectively improved the efficiency of measurement, in relatively large journey, ensure the precision measured, reduce simultaneously and measure cost.

Accompanying drawing explanation

Fig. 1 is the overall structure axonometric chart of the present invention；

Fig. 2 is the sectional view of the present invention；

Fig. 3 is the operation principle schematic diagram of the present invention.

Detailed description of the invention

As illustrated in fig. 1 and 2, variable orifice calipers based on capacitor with multiple electrode plates sensor, including battery lead plate 1, slide block 2, end cap 3, driving shaft 4, housing 5, driven wheel of differential 6 and drive bevel gear 7；The top of housing 5 offers four the chute 5-1 being circumferentially radially arranged, and bottom is connected by screw with end cap 3；The bottom opening of chute 5-1 is in the top inner wall of housing 5；The inside center of housing 5 is provided with integrated driven shaft 5-2；Driven wheel of differential 6 is bearing on driven shaft 5-2 by bearing；Drive bevel gear 7 is fixed with driving shaft 4；Driving shaft 4 is bearing on housing 5 by bearing, and one end is stretched out outside housing 5；Driven wheel of differential 6 engages with drive bevel gear 7, and the angle between driven wheel of differential 6 and drive bevel gear 7 axis is 90 °.Four pieces of slide blocks 2 are separately positioned in a chute 5-1 of housing 5, and all flat threads with driven wheel of differential 6 top of the screw thread bottom four pieces of slide blocks 2 engage；The medial wall of every piece of slide block 2 is fixed with an electrode plate 1；Battery lead plate 1 is cylindricality, and cross section is ring-type in fan；The central angle of battery lead plate 1 correspondence is 60 °；Four electrode plate 1 are uniformly distributed along the circumference, and four electrode plate 1 place circle diameter adjustable extents are 10～25mm.

As it is shown on figure 3, four electrode plate 1 and treat that the hole wall of gaging hole 8 constitutes four capacitors, ignoring the impact of edge effect, each battery lead plate 1 and the capacitance computing formula treated between gaging hole 8 be:

$C=\frac{\mathrm{\ζ\ϵL}}{\ln \frac{R}{r}}---\left(1\right)$

In formula (1), ε is the dielectric constant of air；L is the axial length of battery lead plate 1；R is the radius treating gaging hole 8；R is the lateral wall radius of battery lead plate 1, and ζ is the central angle of battery lead plate 1 correspondence.

By in formula (1)Employing Taylor's formula is launched, and makes R-r=Δ r；Δ r is battery lead plate 1 and treat the radial clearance of gaging hole 8, takes r=1000 Δ r, can obtain:

$\ln \frac{R}{r}=\ln \left(\frac{r+\mathrm{\Δr}}{r}\right)=\frac{\mathrm{\Δr}}{r}---\left(2\right)$

Formula (2) is substituted in formula (1) and can obtain:

$C=\frac{\mathrm{\ζ\ϵLr}}{\mathrm{\Δr}}---\left(3\right)$

Four electrode plate 1 are measured capacitance C of four capacitors obtained, substitutes into formula (3) respectively, try to achieve four electrode plate 1 and four values of the radial clearance Δ r treating gaging hole 8, then averageCalculate the aperture value treating gaging hole 8

The operation principle of this variable orifice calipers based on capacitor with multiple electrode plates sensor:

Using this variable orifice calipers based on capacitor with multiple electrode plates sensor as gauge head, housing 5 clamping is on three-dimensional motion mechanism (such as Digit Control Machine Tool, coordinate measuring machine), and measured workpiece is fixing on the table.Estimate the pore size treating gaging hole 8, drive bevel gear 7 is driven to rotate by rotating driving shaft 4, drive bevel gear 7 and driven wheel of differential 6 engaged transmission, driven wheel of differential 6 drives four pieces of slide blocks 2 circumferentially to radially slide, thus regulate the diameter of four electrode plate 1 place circumference, it is allowed to the pore size adapting to treat gaging hole 8.Four electrode plate 1 are stretched in treating gaging hole 8, and four electrode plate 1 all load 5V voltage, can measure.Three-dimensional motion mechanism drives this variable orifice calipers based on capacitor with multiple electrode plates sensor along treating moving axially of gaging hole 8, the radial distance of four electrode plate 1 is adjusted in conjunction with driving shaft 4, the multiple accurate measurement treating gaging hole, the shoulder hole being more or less the same including through hole, blind hole, micro hole and aperture can be realized；Particularly aperture is the hole measurement to be measured of 10～25mm, it is ensured that certainty of measurement, reduces simultaneously and measures cost.

Claims (5)

1. variable orifice calipers based on capacitor with multiple electrode plates sensor, including battery lead plate, slide block, driving shaft, housing, driven wheel of differential and drive bevel gear, it is characterised in that:

The top of described housing offers the multiple chutes being circumferentially radially arranged；The bottom opening of described chute is in the top inner wall of housing；The inside center of described housing is provided with integrated driven shaft；Described driven wheel of differential is bearing on driven shaft by bearing；Described drive bevel gear is fixed with driving shaft；Described driving shaft is bearing on housing by bearing, and one end is stretched out outside housing；Described driven wheel of differential engages with drive bevel gear；Being equipped with slide block in each chute of described housing, the screw thread of every piece of slider bottom all flat threads with driven wheel of differential top engage；The medial wall of every piece of slide block is fixed with an electrode plate；Described battery lead plate is cylindricality, and cross section is ring-type in fan；All battery lead plates are uniformly distributed along the circumference.

Variable orifice calipers based on capacitor with multiple electrode plates sensor the most according to claim 1, it is characterised in that: the bottom of described housing removably connects with end cap.

Variable orifice calipers based on capacitor with multiple electrode plates sensor the most according to claim 1, it is characterised in that: the angle between described driven wheel of differential and drive bevel gear axis is 90.

Variable orifice calipers based on capacitor with multiple electrode plates sensor the most according to claim 1, it is characterised in that: the central angle that described battery lead plate is corresponding is 30～70 °.

Variable orifice calipers based on capacitor with multiple electrode plates sensor the most according to claim 1, it is characterised in that: described battery lead plate place circle diameter adjustable extent is 10～25mm.