CN101832758A - Measurement device and measurement method for cam shaft diameter of laser scanning engine - Google Patents

Abstract

The invention discloses a measurement device and a measurement method for cam shaft diameter of a laser scanning engine. The measurement device comprises an aligning laser source, a scanning optical flat, a lens and a photoelectric receiver which are sequentially arranged; the scanning optical flat is driven by a direct current (DC) servo motor to operate; a signal processing and control circuit used for amplification, reshaping, counting and motor control of a photoelectric signal is arranged between the DC servo motor and the photoelectric receiver, and a cam shaft to be measured is arranged between the scanning optical flat and the lens. The measurement method comprises the following steps: determining the phase information corresponding to outline involutes of the cam shaft; scanning the setting range; setting the moment that a laser beam just enters a scanning area, the moment that the laser beam is just sheltered by the cam shaft, the moment that the laser beam leaves the other edge of the cam shaft and the starting moment of the next measurement period; and calculating the diameter d of the cam shaft to be measured. The invention has simple structure, convenient manufacturing, rapid measurement speed and high efficiency, utilizes a non-contact laser scanning mode having no damage to the cam shaft to be measured, and has the accuracy of 1 mu m.

Description

Cam shaft diameter of laser scanning engine measurement mechanism and measuring method

Technical field

The present invention relates to a kind of engine cam diameter measurement.Particularly relate to a kind of to the cam shaft diameter of laser scanning engine measurement mechanism and the measuring method of tested camshaft surface without any damage.

Background technology

Camshaft is one of core component of engine, it moves up and down by the continuous rotation promotion valve stem of self, and then the open and close of control valve, thereby its overall size and shape error be to influence the principal element that valve opens and closes gap length and distribution efficient, directly influences the power output of engine.Along with the high speed development of auto industry and the raising of manufacturing process, automated production is extensively adopted in the processing of camshaft, traditional optical-mechanical amount instrument and model are measured can not adapt to the production needs, and high precision, high efficiency camshaft general measuring instrument are very important.

At present, the dividing apparatus of camshaft measuring machine mostly adopts the disk light beam encoder measuring system, and line value device adopts the linear grating measuring system.The control signal that computing machine sends starts the direct current synchronous motor rotation, precise rotary shaft frenulum moving cam axle rotates, by revolving shaft circular raster sensor and radial alignment grating sensor respectively with the angular displacement of camshaft, radially, axial displacement converts the light intensity variable signal of light and shade striped to, send into computing machine through the photosignal conversion and after handling, just obtain the radial measurement value (lift) of each cam contour corresponding to each corner by data analysis.This method adopts rigidity gauge head contact measured object, easily scuffing is caused on the measured object surface, and complex structure, cost height.

Because the optical non-contact measurement has that speed is fast, precision is high, to advantages such as measured object are harmless, be applied to the camshaft detection range in recent years.Use spatial digitizer that camshaft is carried out segmentation based on the CCD dimensional visual measurement method of machine vision and take, the measurement result of All Ranges is stitched together forms complete pattern again.Need carry out the preliminary work at measured object surface binding mark point or feature body during actual measurement, be subjected to the restriction of image characteristics extraction and stitching algorithm simultaneously, measuring accuracy can only reach 10 ^-2The mm order of magnitude.

Summary of the invention

Technical matters to be solved by this invention is, provides a kind of employing non-contacting laser scanning methods, to tested camshaft surface without any damage, cam shaft diameter of laser scanning engine measurement mechanism and measuring method that measuring speed is fast, efficient is high.

The technical solution adopted in the present invention is: a kind of cam shaft diameter of laser scanning engine measurement mechanism and measuring method.The cam shaft diameter of laser scanning engine measurement mechanism, comprise and setting gradually: collimation laser light source, scanning optical flat, lens and photelectric receiver, described scanning optical flat drives running by DC servo motor, be connected with the signal Processing and the control circuit that are used for photosignal is amplified shaping, counting and Electric Machine Control between described DC servo motor and the photelectric receiver, be used to place tested camshaft between described scanning optical flat and the lens.

Described collimation laser light source is made up of diode laser, optical fiber and optical fiber collimator, and the light that diode laser produces reaches outgoing behind the optical fiber collimator along optical fiber.

Described tested camshaft is mounted in precise rotary shaft and fastens.

Be used for the measuring method of cam shaft diameter of laser scanning engine measurement mechanism, comprise the steps:

1) tested camshaft is installed in precise rotary shaft and fastens, read the angle of revolution, to determine the phase information of camshaft profile involute urve correspondence by the circular raster sensor that axle is fastened;

2) will scan optical flat and be installed in by clamping device and do uniform rotation on the DC servo motor, light source scans setting range after sending collimated laser beam transmission scan optical flat;

3) establish: the moment that laser beam has just entered scanning area is t ₀, laser beam has just been blocked by camshaft and has been t constantly ₁, laser beam leaves another edge of camshaft and is t constantly ₂, t ₀+ T represents the beginning of next measuring period constantly;

4) diameter d of the tested camshaft of calculating:

Maximum incident angle is by the length L and the width D decision of scanning optical flat, promptly

${\mathrm{\θ}}_{\max }=\frac{\mathrm{\π}}{2}-\arctan \frac{D}{L}$

If extraneous refractive index is 1, optical flat material refractive index is n, and then the pass of the side-play amount S of scanning light beam and incident angle θ is:

$S=D*\sin \mathrm{\&theta;}*(1-\cos \mathrm{\&theta;}/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&theta;}})$

The maximum scan zone is

$H=\frac{2D}{\sqrt{D^2+L^2}}*(L-\frac{\mathrm{DL}}{\sqrt{(n^2-1){\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+n^2{D}^2}})$

Measure by timing circuit, the corresponding angle that the scanning optical flat rotates the time T in a week is 2 π

t _iIncident angle constantly

I=1 wherein, 2; θ ₀Be t ₀Light beam irradiates is to the incident angle of optical flat working surface constantly

The diameter of tested camshaft is

$d=D*{\sin \mathrm{\&theta;}}_2*(1-{\cos \mathrm{\&theta;}}_2/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&theta;}}_2})-D*{\sin \mathrm{\&theta;}}_1*({1-\cos \mathrm{\&theta;}}_1/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&theta;}}_1}).$

Cam shaft diameter of laser scanning engine measuring system letter measuring method of the present invention, simple in structure, be convenient to make, and be to adopt non-contacting laser scanning methods, without any damage, measuring speed is fast, efficient is high to tested camshaft surface, and precision can reach 1 μ m.

Description of drawings

Fig. 1 is that scanning light beam produces synoptic diagram;

Fig. 2 is that measurement mechanism is formed synoptic diagram;

Fig. 3 is a photelectric receiver output signal synoptic diagram.

Wherein:

1: collimation laser light source 2: the scanning optical flat

3: DC servo motor 4: tested camshaft

5: lens 6: photelectric receiver

7: signal Processing and control circuit d: the saltus step of camshaft coboundary

E: camshaft lower limb saltus step

Embodiment

Below in conjunction with embodiment and accompanying drawing cam shaft diameter of laser scanning engine measuring system letter measuring method of the present invention is made a detailed description.

As shown in Figure 2, cam shaft diameter of laser scanning engine measurement mechanism of the present invention, comprise and setting gradually: collimation laser light source 1, scanning optical flat 2, lens 5 and photelectric receiver 6, described scanning optical flat 2 drives running by DC servo motor 3, be connected with the signal Processing and the control circuit 7 that are used for photosignal is amplified shaping, counting and Electric Machine Control between described DC servo motor 3 and the photelectric receiver 6, be used to place tested camshaft 4 between described scanning optical flat 2 and the lens 5.Described tested camshaft 4 is mounted in precise rotary shaft and fastens, and control circuit is responsible for producing synchronous control signal.Described collimation laser light source 1 is made up of diode laser, optical fiber and optical fiber collimator, and the light that diode laser produces reaches outgoing behind the optical fiber collimator along optical fiber.

In an embodiment of the present invention: diode laser is selected for use: LPM-660-PC; Optical fiber collimator is selected for use: CFS2-1064-FC; DC servo motor is selected for use: MAXON EC 4550w; Electric machine controller used in signal Processing and the control circuit is selected for use: EPOS24-5; Photoelectric encoder is selected for use: the HKT30-3011000 line.

The measuring principle of cam shaft diameter of laser scanning engine measuring method of the present invention is: when parallel beam scans tested camshaft, and by the photelectric receiver reception that is placed on tested camshaft back, project the light crested when camshaft is arrived in beam flying on the photelectric receiver, so photelectric receiver output is a square-wave pulse, by the anglec of rotation that measures scanning light beam, finally determine the cam shaft diameter size by the rule of light beam transmission optical flat generation offset distance to square wave signal time phase place.

Producing highly parallel scanning light beam is the gordian technique that guarantees measuring accuracy, and the generation principle of scanning light beam as shown in Figure 1 among the present invention.When a branch of light shines optical flat with incident angle θ from air, can refraction effect can take place at incidence point a place, reflect once more during by the b point outgoing of optical flat, the deflection angle of twice refraction is identical, make the direction of propagation of emergent ray can not change, be translation apart from S, promptly formed certain scanning area.

$S=D*\sin \mathrm{\&theta;}*(1-\cos \mathrm{\&theta;}/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2\mathrm{\&theta;}})---\left(1\right)$

D is the thickness of optical flat in the formula, and n is the refractive index of optical flat.

Because the restriction of optical flat physical dimension, incident angle can not reach pi/2, and maximum incident angle is by the length L and the width D decision of optical flat, promptly

${\mathrm{\&theta;}}_{\max }=\frac{\mathrm{\&pi;}}{2}-\arctan \frac{D}{L}---\left(2\right)$

The maximum scan zone is so

$H=\frac{2D}{\sqrt{D^2+{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">L</figure-callout>}}^2}}*(L-\frac{\mathrm{DL}}{\sqrt{(n^2-1){\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">L</figure-callout>}}^2+n^2{D}^2}})---\left(3\right)$

During measurement, tested camshaft 4 is installed in precise rotary shaft and fastens, and is positioned between scanning optical flat and the photelectric receiver, and the circular raster sensor that fasten by axle the angle of revolution is read, as shown in Figure 2.Infrared laser light source 1 produces a branch of collimated light beam, when scanning optical flat 2 is installed in by clamping device when doing uniform rotation counterclockwise on the DC servo motor 3 under the drive of DC servo motor 3, control signal is carried out synchronously motor, scanning light beam bc will move from bottom to top, leave lens 5 along b ' c ' at last, the light beam between optical flat and the lens 5 is the parallel beam that is parallel to systematic optical axis.Photelectric receiver 6 signal in the time of beam flying survey part is zero, and output is arranged when being in other scanning area, signal and control circuit 7 is responsible for photosignal amplified operations such as shaping, counting and Electric Machine Control, and the scanning optical flat turns to a ' time by a and finishes the one-shot measurement scan period.

Cam shaft diameter of laser scanning engine measuring method of the present invention specifically comprises the steps:

1) tested camshaft is installed in precise rotary shaft and fastens, read the angle of revolution, to determine the phase information of camshaft profile involute urve correspondence by the circular raster sensor that axle is fastened;

2) will scan optical flat and be installed in by clamping device and do uniform rotation on the DC servo motor, light source scans setting range after sending infrared collimated laser beam transmission scan optical flat;

3) as shown in Figure 3, according to the photelectric receiver output waveform originally scanning light beam do not enter scanning area as yet, photelectric receiver is output as zero, when light beam has just entered scanning area and do not scanned tested camshaft, photelectric receiver has signal output, records this and is t constantly ₁When blocking when light beam continuation scanning and by camshaft, the photelectric receiver output signal is zero, and when light beam left the camshaft edge, photoelectric tube had signal output once more, recorded this and was t constantly ₂Leave scanning area when light beam continues to scan, photoelectric tube output reverts to zero.

If: the moment that laser beam has just entered scanning area is t ₀, laser beam has just been blocked by camshaft and has been t constantly ₁, laser beam has just left the camshaft edge and has been t constantly ₂, t ₀+ T represents the beginning of next measuring period constantly;

4) diameter d of the tested camshaft of calculating:

At t ₀The effect of synchronizing pulse constantly begins t following measuring period ₁Signal level variation has constantly represented to scan an end margin of tested camshaft, t ₂Signal level represents that light beam leaves tested camshaft constantly, then t ₀+ T represents the beginning of next measuring period constantly.Be exactly the time T that the scanning optical flat rotates a week measuring period, can measure by timing circuit, and corresponding angle is 2 π, if calibrate out t in advance ₀Corresponding constantly incident angle θ ₀, be about to time quantum t ₁And t ₂Convert angular metric to, pass through t so _iIncident angle constantly

${\mathrm{\&theta;}}_i=\frac{t_i-t_0}{T}*2\mathrm{\&pi;}+{\mathrm{\&theta;}}_0$ (i=1,2; θ ₀Be t ₀Incident angle constantly) (4)

Measure and calculate the side-play amount S of light beam when scanning two edges of camshaft ₁And S ₂, S ₂-S ₁Be cam shaft diameter d:

$d=D*{\sin \mathrm{\&theta;}}_2*(1-{\cos \mathrm{\&theta;}}_2/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&theta;}}_2})-D*{\sin \mathrm{\&theta;}}_1*({1-\cos \mathrm{\&theta;}}_1/\sqrt{n^2-{\mathrm{<figure-callout\; id="2"\; label="sin"\; filenames="HDA0000021432070000012.png"\; state="\{\{state\}\}">sin</figure-callout>}}^2{\mathrm{\&theta;}}_1})---\left(5\right)$ Finally finish the diameter measurement task.

Claims (4)

1. cam shaft diameter of laser scanning engine measurement mechanism, it is characterized in that, comprise and setting gradually: collimation laser light source (1), scanning optical flat (2), lens (5) and photelectric receiver (6), described scanning optical flat (2) drives running by DC servo motor (3), be connected with the signal Processing and the control circuit (7) that are used for photosignal is amplified shaping, counting and Electric Machine Control between described DC servo motor (3) and the photelectric receiver (6), be used to place tested camshaft (4) between described scanning optical flat (2) and the lens (5).

2. cam shaft diameter of laser scanning engine measurement mechanism according to claim 1, it is characterized in that, described collimation laser light source (1) is made up of diode laser, optical fiber and optical fiber collimator, and the light that diode laser produces reaches outgoing behind the optical fiber collimator along optical fiber.

3. cam shaft diameter of laser scanning engine measurement mechanism according to claim 1 is characterized in that, described tested camshaft (4) is mounted in precise rotary shaft and fastens.

4. a measuring method that is used for the described cam shaft diameter of laser scanning engine measurement mechanism of claim 1 is characterized in that, comprises the steps:

1) tested camshaft is installed in precise rotary shaft and fastens, read the angle of revolution, to determine the phase information of camshaft profile involute urve correspondence by the circular raster sensor that axle is fastened;

2) will scan optical flat and be installed in by clamping device and do uniform rotation on the DC servo motor, light source scans setting range after sending collimated laser beam transmission scan optical flat;

3) establish: the moment that laser beam has just entered scanning area is t ₀, laser beam has just been blocked by camshaft and has been t constantly ₁, laser beam leaves another edge of camshaft and is t constantly ₂, t ₀+ T represents the beginning of next measuring period constantly;

4) diameter d of the tested camshaft of calculating:

Maximum incident angle is by the length L and the width D decision of scanning optical flat, promptly

${\mathrm{\&theta;}}_{\max }=\frac{\mathrm{\&pi;}}{2}\arctan \frac{D}{L}$

If extraneous refractive index is 1, optical flat material refractive index is n, and then the pass of the side-play amount S of scanning light beam and incident angle θ is:

$S=D*\sin \mathrm{\&theta;}*(1-\cos \mathrm{\&theta;}/\sqrt{n^2-{\sin }^2\mathrm{\&theta;}})$

The maximum scan zone is

$H=\frac{2D}{\sqrt{D^2+L^2}}*(L-\frac{\mathrm{DL}}{\sqrt{(n^2-1)L^2+n^2{D}^2}})$

Measure by timing circuit, the corresponding angle that the scanning optical flat rotates the time T in a week is 2 π

t _iIncident angle constantly I=1 wherein, 2; θ ₀Be t ₀Light beam irradiates is to the incident angle of optical flat working surface constantly

The diameter of tested camshaft is

$d=D*\sin {\mathrm{\&theta;}}_2*(1-\cos {\mathrm{\&theta;}}_2/\sqrt{n^2-{\sin }^2{\mathrm{\&theta;}}_2})-D*\sin {\mathrm{\&theta;}}_1*(1-\cos {\mathrm{\&theta;}}_1/\sqrt{n^2-{\sin }^2{\mathrm{\&theta;}}_1}).$

Images