CN102607430B - Grating line displacement transducer - Google Patents

Abstract

The invention relates to a grating line displacement transducer, which belongs to the technical field of photoelectric measurement and aims at improving the measurement precision of the existing grating line displacement transducer. The grating line displacement transducer comprises a carriage body, a pressure spring, a pulley, a hemisphere-head small shaft, a carriage, a pin shaft, five rolling bearings, a main grating and a big-head screw, wherein the carriage body and one end of the pressure spring are fixed to form a whole by the big-head screw, and the other end of the pressure spring is pressed in an arc groove of the pulley; the pulley is fixed on the carriage by the pin shaft; the hemisphere-head small shaft is arranged at the right lower end of the carriage body, and the hemisphere-head part of the hemisphere-head small shaft is in close contact with the carriage; and the five rolling bearings are arranged on the carriage, and the rolling surfaces of the rolling bearings are in close contact with the main grating. According to the grating line displacement transducer, the measurement precision of a grating bar is greatly improved; meanwhile, the cost increase is small, and the grating line displacement transducer has wide application space in the technical field of the photoelectric measurement.

Description

Optical grid line displacement sensor

Technical field

The present invention relates to optical grid line displacement sensor, belong to photoelectric measurement technical field.

Background technology

In the structure of closed optical grid line displacement sensor, it is all the degree of freedom that adopts five rolling bearing restriction indication grating balladeur trains, it can only be moved along required direction of measurement, adopt a spring to press to indication grating balladeur train, five bearings are reliably contacted with the guide pass on key light grid, guarantee the normal transmission of its photosignal, this spring plays again the effect of traction balladeur train simultaneously.This form structure is simple, but can bring sizable measuring error, very unfavorable to guaranteeing the measuring accuracy of grating scale.

As shown in Figure 1: drag spring 10 is installed on sliding rack body 1, and the other end of drag spring and steel ball 11 are fixed together, the precompression due to drag spring 10 tightly crouches in the bellmouth of balladeur train 5 steel ball; When sliding rack body moves left and right along the direction of arrow, pull drag spring 10, drag spring to move left and right by steel ball 11 traction balladeur trains.At this moment the transfer route of the measurement point of sensor is C → B → A, and BC is vertical with moving direction under normal circumstances; But in the time of 8 bending of key light grid, as shown in Figure 2, at this moment BC becomes a low-angle β with moving direction out of plumb, with vertical direction, and has brought measuring error δ=tg β * BC=β * BC, works as BC=5mm, β=10 ' time, δ=0.015mm.As can be seen here, this error is very important.

Summary of the invention

In order to improve the measuring accuracy of existing optical grid line displacement sensor, the invention provides a kind of optical grid line displacement sensor.

The technical solution used in the present invention is as follows:

Optical grid line displacement sensor, comprise: sliding rack body, holddown spring, pulley, the little axle of hemispherical head, balladeur train, bearing pin, five rolling bearings, key light grid and major part screw rods, one end of described sliding rack body and holddown spring is fixed into one by major part screw rod, and the other end of holddown spring is pressed in the arc groove of pulley; Described pulley is fixed on balladeur train by bearing pin; The little axle of described hemispherical head is arranged on the bottom righthand side of sliding rack body, and the hemisphere head of the little axle of hemispherical head and balladeur train close contact; Five rolling bearings are set, the rolling surface of described rolling bearing and key light grid close contact on described balladeur train.

The invention has the beneficial effects as follows: the present invention, by holddown spring and a little axle of hemispherical head with three direction snap-in forces, has realized the sliding rack body of grating scale linear movement pick-up and the sealing of the power between the little axle of hemispherical head; The present invention has improved the measuring accuracy of grating scale greatly, realizes cost increase of the present invention but seldom simultaneously.

Accompanying drawing explanation

Fig. 1 is the structural representation of conventional grating scale linear movement pick-up;

Fig. 2 is the error analysis schematic diagram of conventional grating scale linear movement pick-up;

Fig. 3 is optical grid line displacement sensor front view of the present invention;

Fig. 4 is optical grid line displacement sensor right view of the present invention;

Fig. 5 is the error analysis schematic diagram of optical grid line displacement sensor of the present invention;

Fig. 6 is the force analysis schematic diagram figure that k is ordered;

Fig. 7 is the shape front view of holddown spring of the present invention;

Fig. 8 is the shape vertical view of holddown spring of the present invention;

Fig. 9 is the three-dimensional structure schematic diagram of holddown spring of the present invention.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in further details.

As shown in Figure 3 and Figure 4, optical grid line displacement sensor, comprises sliding rack body 1, holddown spring 2, pulley 3, the little axle 4 of hemispherical head, balladeur train 5, bearing pin 6, rolling bearing 7, key light grid 8 and major part screw rod 9.At the lower-left of sliding rack body 1 end, by major part screw rod 9, a holddown spring 2 is installed, the other end of holddown spring 2 is pressed in the arc groove of pulley 3; Pulley 3 is fixed on balladeur train by bearing pin 6, and pulley 3 can be around the center line rotation of bearing pin 6; The little axle 4 of hemispherical head of the oblique installation of bottom righthand side at sliding rack body 1, the little axle 4 of hemispherical head is fixed into one with sliding rack body 1 by riveting method, the little axle 4 of hemispherical head contacts at D point with balladeur train 5, is fixed on the close as far as possible key light grid 8 of the little axle 4 of hemispherical head on sliding rack body 1, and key light grid 8 do not rub again; The snap-in force of holddown spring 2 guarantees that the rolling surface of five rolling bearings 7 on balladeur train 5 reliably contacts with key light grid 8, has also guaranteed the socket cap close contact of balladeur train 5 with the little axle 4 of hemispherical head simultaneously; When sliding rack body 1 drives holddown spring 2 and the little axle 4 of hemispherical head to move along the direction of arrow, balladeur train 5, under the clamping of holddown spring 2 and the little axle 4 of hemispherical head, moves along key light grid by five rolling bearings 7.

The lower left quarter of the left end of holddown spring 2 and sliding rack body 1 is fixed on A point, holddown spring 2 has downward predeformation forward, its right-hand member is bent upwards, at sliding rack body 1 and balladeur train 5 during in normal operation position, because the snap-in force of holddown spring 2 makes holddown spring 2 press the point in the k of pulley 3.

As shown in Figure 6, the suffered spring force f of k point can resolve into the component of three directions: along the component fx of sliding rack body 1 moving direction (sensor measurement direction), perpendicular to the component fz of key light grid 8, perpendicular to the component fy of the side of key light grid 8; Component fz and fy press to five rolling bearings 7, and five rolling bearings 7 are contacted reliably with key light grid, and component fx pushes balladeur train 5 to the right side, make balladeur train 5 and the little axle 4 of hemispherical head be contacted with reliably D point.Guaranteed that five rolling bearings 7 contact with the reliable of key light grid 8, realized again the sealing to the power between balladeur train 5 and the little axle 4 of hemispherical head.

As shown in Figure 3, A point and D point are rigidly attached on sliding rack body 1, can be regarded as a bit, so the transmission of the measurement point of a kind of optical grid line displacement sensor of the present invention are C → D (A).As shown in Figure 5, when key light grid 8 are when being crooked, balladeur train 5 moves to E point with the contact point of the little axle 4 of hemispherical head by D, and BC is also no longer vertical with sliding rack body moving direction, but becomes a low-angle β with vertical direction; CD and CDE also all with the origin-location low-angle β that tilted.The error of being brought by the inclination of CD is:

$\mathrm{\δ}=\mathrm{CD}-\mathrm{Cd}*\cos \left(\mathrm{\β}\right)=\mathrm{CD}*(1-\cos \left(\mathrm{\β}\right))=2\mathrm{CD}{\left(\frac{\mathrm{\β}}{2}\right)}^2=\frac{1}{2}\mathrm{CD}{\mathrm{\β}}^2$

Can find out that the error that CD tilts to bring is second order error, can ignore.

The error delta of being brought by the inclination of CDE ₁=tg β * DE, the length of DE is very little, within caning be controlled in 1mm, works as DE=1mm, β=10 ' time, δ ₁=0.003mm, this error reduces greatly as seen.

As shown in Figure 7 to 9, the structure of holddown spring 2 in known the present invention, its material is spring steel wire, cross sectional shape is circular.

Claims (3)

1. optical grid line displacement sensor, comprise: sliding rack body (1), holddown spring (2), pulley (3), the little axle of hemispherical head (4), balladeur train (5), bearing pin (6), five rolling bearings (7), key light grid (8) and major part screw rod (9), it is characterized in that, described sliding rack body (1) is fixed into one with one end of holddown spring (2) by major part screw rod (9), and the other end of holddown spring (2) is pressed in the arc groove of pulley (3); Described pulley (3) is fixed on balladeur train (5) by bearing pin (6); The little axle of described hemispherical head (4) is arranged on the bottom righthand side of sliding rack body (1), and the hemisphere head of the little axle of hemispherical head (4) and balladeur train (5) close contact; Five rolling bearings (7) are set, the rolling surface of described rolling bearing (7) and key light grid (8) close contact on described balladeur train (5).

2. optical grid line displacement sensor according to claim 1, is characterized in that, described sliding rack body (1) and the little axle of hemispherical head (4) are fixed into one by riveting method.

3. optical grid line displacement sensor according to claim 1, is characterized in that, the little axle of described hemispherical head (4) near and do not contact key light grid (8).

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