CN106705900B - Hole-shape-adaptive inner hole cylindricity pneumatic composite detection device and measurement method - Google Patents

Abstract

The invention discloses a pneumatic composite detection device for inner hole cylindricity with self-adaptive hole shape and a measurement method. Including the pneumatic measuring assembly and its matching calibration gauge, there are four sets of taper pneumatic nozzles and four straightness pneumatic nozzles on the pneumatic measuring head; the pneumatic nozzle is calibrated first, and then the straightness error, roundness error and taper error are measured simultaneously. Then, the first qualification judgment is carried out, the average diameter of the four cross-sections of the inner hole is measured and obtained, and the hole shape of the inner hole is obtained by the average diameter of the four cross-sections. Error value, and finally make a second qualification judgment. The composite pneumatic detection device and the measurement method disclosed by the invention can effectively discriminate various inner hole shapes, and calculate the cylindricity by using an adaptive algorithm. detection, greatly improve the measurement efficiency.

Description

Hole shape adaptive pneumatic composite detection device and measurement method of inner hole cylindricity

technical field

The invention relates to an inner hole precision detection device and a measurement method, in particular to a hole shape adaptive inner hole cylindricity pneumatic composite detection device and measurement method for on-site detection of a precision matching inner hole.

Background technique

The machining accuracy of the precision-fit inner hole is a key factor in determining the performance of some components. The cylindricity error of the inner hole is an important performance index to ensure the matching accuracy. The cylindricity error requirements of designers for precision fitting holes are often only a few microns, and the inner holes are mostly slender, so the detection of inner hole cylindricity becomes more and more difficult.

At present, the detection of the inner hole cylindricity of products in the market mainly includes the traditional pneumatic measuring method, the roundness method and the three-coordinate measuring machine method. The traditional pneumatic inspection detects a single shape error of the inner hole, such as straightness or taper to replace the cylindricity. Obviously, this measurement method is difficult to adapt to different hole shapes, and the evaluation result has a large error with the real cylindricity, which is difficult to meet measurement requirements. In addition, this method replaces cylindricity by a single shape error, contains little information about the inner hole, and has poor representation.

In the patent "A Comprehensive Detection Device and Test Method for Steering Gear Rack Accuracy Value (201610025563.5)", Liu Huijian et al. used the diameter range, runout range and straightness values of the measured slender rods to calculate the cylindricity. In this device, the use of guide rails to measure the straightness will introduce a large error. When the precision reaches the micron level, it is difficult to measure accurately. In addition, there is no detailed cylindricity calculation formula in this paper.

The roundness meter method and the three-coordinate measuring machine method are the most accurate in detecting the cylindricity of the inner hole, but they need to be detected in a special measuring room. The detection steps are complicated, the cycle is long, and the cost is high. On-site inspection. Especially when inspecting inner holes that need to be repeatedly corrected, the long inspection cycle leads to low production efficiency.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide an inner hole cylindricity pneumatic composite detection device and a measuring method with adaptive hole shape, which has the characteristics of hole shape adaptation and can detect the cylindricity of elongated inner holes with high precision. Error, and realize production site inspection, improve production efficiency.

The technical scheme adopted in the present invention is:

1. A pneumatic composite detection device for inner hole cylindricity with adaptive hole shape:

Including the pneumatic measuring assembly and its matching calibration gauge.

The pneumatic measuring assembly includes a trachea protective sleeve, a spring, a nut, a handle, a limit baffle and a pneumatic measuring head; Positioning, the handle is a hollow structure, the trachea protective sleeve and the spring are fixedly connected to the nut at the end of the handle through a nut.

There are four groups of taper pneumatic nozzles and four straightness pneumatic nozzles on the pneumatic measuring head, of which: the four groups of taper pneumatic nozzles are divided into two groups, and the two taper pneumatic nozzles of each group are symmetrically arranged on the same cross section of the pneumatic measuring head. On both sides, different groups of taper pneumatic nozzles are arranged on different cross sections of the pneumatic measuring head, and all the taper pneumatic nozzles are arranged on the same axial section of the pneumatic measuring head. The pneumatic measuring instrument is connected, and the trachea is connected to the pneumatic measuring instrument after passing through the handle and the tracheal protective sleeve, so that the four groups of taper pneumatic nozzles form four-way taper pneumatic detection arranged at intervals along the axial direction; among the four straightness pneumatic nozzles, two of them are straight The straightness pneumatic nozzle is arranged on the same side of the middle of the pneumatic measuring head, the other two straightness pneumatic nozzles are arranged on the other side of the two ends of the pneumatic measuring head, and the four straightness pneumatic nozzles are arranged on the same axial section of the pneumatic measuring head. The axial section where the straightness pneumatic nozzle is located is perpendicular to the axial section where the taper pneumatic nozzle is located. All straightness pneumatic nozzles are connected to the same pneumatic measuring instrument after passing through the same trachea. After the trachea passes through the handle and the trachea protective sleeve Connect the pneumatic measuring instrument, so that the four straightness pneumatic nozzles form a taper pneumatic detection.

The matching calibration gauge includes a straightness upper limit calibration gauge, a straightness lower limit calibration gauge, an auxiliary calibration gauge, a diameter upper limit calibration gauge and a diameter lower limit calibration gauge, and the five calibration gauges are all collar structures.

The outer side wall of the pneumatic measuring head is provided with a plurality of guide grooves along the axial direction, and the guide grooves are arranged beside an exhaust dynamic nozzle along the axial direction and communicate with the annular groove of the pneumatic nozzle.

The straightness pneumatic nozzle and the taper pneumatic nozzle are simultaneously arranged on the pneumatic measuring head, and at the same time, various shape errors of the inner hole are measured to obtain the cylindricity.

2. A pneumatic composite measurement method of inner hole cylindricity with adaptive hole shape, which adopts the following steps:

1) Pneumatic nozzle calibration: calibrate the straightness measuring nozzle and taper measuring nozzle on the pneumatic measuring head respectively, use the upper straightness calibration gauge, the lower straightness calibration gauge and the auxiliary calibration gauge to calibrate the straightness measurement nozzle, use the upper diameter calibration gauge, Diameter lower limit calibration gauge to calibrate taper measuring nozzle;

2) Simultaneously measure straightness error, roundness error and taper error:

Put the composite measuring device into the hole to be measured, and the limit baffle is in contact with the outer end face of the inner hole, so that the axial direction of the pneumatic measuring head and the measured hole are overlapped and positioned, and then rotate the pneumatic measuring head 360 degrees around, through five A pneumatic measuring instrument is measured in the following ways, and the measurement data of straightness, roundness and taper are recorded and obtained, specifically, the straightness of the inner hole axis δ _A , the inner hole roundness δ _B , δ _C of the cross section where the four groups of taper pneumatic nozzles are located , δ _D , δ _E and inner hole taper δ _F ; the data measured by the pneumatic nozzle in the present invention is the diameter data of the place where the pneumatic nozzle is located.

3) The first qualification judgment: use the following formula to find the maximum value in all measured data

与圆柱度公差要求Δ进行比较，若

则认为不符合公差要求，工件内孔加工不合格；若

则继续下一步骤；and set the maximum value

Compared with the cylindricity tolerance requirement Δ, if

It is considered that the tolerance requirements are not met, and the inner hole processing of the workpiece is unqualified; if

then proceed to the next step;

4) Measure the average diameter of the four cross-sections of the inner hole, and obtain the hole shape of the inner hole by the average diameter of the four cross-sections;

5) Adaptive cylindricity calculation is carried out using the primary and secondary distinction method to obtain the cylindricity error value δ;

6) The second qualification judgment: compare the cylindricity error value δ and the cylindricity tolerance requirement Δ again. When δ≤Δ, it is considered that the inner hole of the workpiece is qualified; when δ>Δ, it is considered that the inner hole of the workpiece is processed. Processing failed.

Described step 2) is specifically:

1) Straightness: During one rotation of the pneumatic measuring head, record the diameter data collected by the pneumatic measuring instrument connected to the straightness pneumatic nozzle in real time, subtract the minimum value from the maximum value collected, and take two of the difference after subtraction. One part is used as the straightness δ _A of the inner hole axis;

Ⅱ) Roundness: During the rotation of the pneumatic measuring head, the diameter data collected by the pneumatic measuring instruments connected to the four groups of taper pneumatic nozzles are recorded respectively, and the maximum value in the diameter data of the same taper pneumatic nozzle is subtracted from the minimum value. The difference between the values is used as the inner hole roundness, and the inner hole roundness δ _B , δ _C , δ _D , and δ _E of the cross-section where the four groups of taper pneumatic nozzles are located are obtained respectively;

Ⅲ) Taper: when the pneumatic measuring head is at a fixed rotation angle, subtract the minimum value from the maximum value of the diameter data of the four groups of taper pneumatic nozzles, and take one half to obtain the difference, and then rotate the pneumatic measuring head for one cycle to measure , take the maximum value of the difference in all the rotational angle positions as the inner hole taper δ _F .

Described step 4) is specifically:

4.1) Measure and calculate the average diameter of the four cross-sections of the inner hole:

For the four groups of taper pneumatic nozzles of the pneumatic measuring head, all the diameter data during one rotation of the pneumatic measuring head are collected by their respective pneumatic measuring instruments, and the average value is taken as the average diameter of the inner hole of the cross section where the taper pneumatic nozzle is located. Obtain the average diameters d _P0 , d _P1 , d _P2 and d _P3 of the four cross sections in turn, and calculate the average diameter of the four cross sections d _P =(d _P0 +d _P1 +d _P2 +d _P3 )/4;

4.2) Judgment of pore shape based on the relationship of pore size:

Ⅰ) If |(d _P0 , d _P1 , d _P2 , d _P3 ) _{-d P} | Bend the hole, otherwise make a follow-up judgment;

Ⅱ) If d _P0 <(d _P1 , d _P2 )<d _P3 or d _P0 >(d _P1 , d _P2 )>d _P3 , one end of the inner hole is large and the other end is small, showing a tapered shape, which is a tapered hole;

Ⅲ) If d _P0 <(d _P1 , d _P2 ) and d _P3 <(d _P1 , d _P2 ) or d _P0 >(d _P1 , d _P2 ) and d _P3 >(d _P1 , d _P2 ), then The inner hole has a convex shape with a large middle and two small sides, or a concave shape with a large middle and small ends, which is a concave-convex hole;

IV) If none of the above-mentioned situations I, II or III are met, it is a hole of other shape.

The step 5) is specifically to calculate and obtain the cylindricity error value for the equal-diameter curved hole, the tapered hole, the concave-convex hole and other shaped holes in the following ways:

Ⅰ) The cylindricity error value δ is obtained by calculating the following formula for the equal-diameter bending hole. The axis straightness error in the axial section is the main component of the cylindricity error of the equal-diameter bending hole, and the roundness error in the cross-section is the secondary component. part, the cylindricity error is the synthesis of the axis straightness error and the roundness error:

Ⅱ) The cylindricity error value δ is obtained by calculating the following formula for the tapered hole. The taper error in the axial section is the main component of the cylindricity error of the tapered hole, and the roundness error in the cross section is the secondary component. The cylindricity The error is a combination of taper error and roundness error:

Ⅲ) The cylindricity error value δ is calculated by the following formula for the concave-convex hole. The taper error in the axial section is the main component of the cylindricity error of the concave-convex hole, and the circularity error in the cross section is the secondary component. The cylindricity error is the combination of taper error and roundness error:

Ⅳ) For other shaped holes, use the following formula to calculate the cylindricity error value δ, the maximum value of all roundness error values, taper error values, and straightness error values plus the maximum value of the above-mentioned values in the section where the maximum value is not located. Semi is used as the cylindricity error value, and the two values that make up the cylindricity error value are respectively taken from the error values in the cross section and the two sections in the axial section;

When the roundness error value is the largest:

When the roundness error value is not the maximum:

Among them, δ _A represents the straightness of the inner hole axis, δ _B , δ _C , δ _D , and δ _E are the inner hole roundness of the cross-section where the four groups of taper pneumatic nozzles are located, and δ _F represents the inner hole taper.

The section involved in the present invention includes an axial section parallel to the axial direction and a cross section perpendicular to the axial direction.

In the present invention, when the measurement of the pneumatic detection device is completed, the cylindricity error is calculated by synthesizing the measured straightness error, roundness error and taper error according to the self-adaptive judgment result of the hole shape.

The present invention has the following advantages:

1) The device is a high-precision, composite slender inner hole cylindricity pneumatic detection device with hole shape adaptive characteristics. Traditional pneumatic measuring components can only measure a single roundness error value, straightness error value, etc. to replace cylindricity. The device of the present invention calculates the cylindricity error by using the straightness error value, roundness error value and taper error value measured at the same time, which can better approximate the theoretical cylindricity and greatly improve the measurement accuracy.

2) When the traditional pneumatic measuring component only measures one kind of shape error instead of cylindricity error, it can only measure a specific hole shape, and cannot accurately measure other shapes of holes. For example, a probe measuring tapered holes is difficult to accurately measure convex holes, because the former error mainly exists in the cross section, while the latter error mainly exists in the shaft section. Similarly, only measuring the roundness error will also face the problem that some hole shapes cannot be measured, resulting in a large measurement error.

And the compound probe disclosed in the present invention can simultaneously measure the straightness error, roundness error and taper error, and calculate the cylindricity by the self-adaptive cylindricity algorithm based on the primary and secondary distinguishing methods, so that the present invention has the advantages of the hole shape. The self-adaptive feature solves the problem that a probe can only measure some special holes.

3) When the traditional pneumatic measuring component replaces the cylindricity error value by the taper approximation, the single-layer measuring head measures step by step, and the axes of the measuring heads at each measuring position cannot be guaranteed to coincide when pulling, which leads to errors. The present invention is an integrated measuring head, which can measure four cross-sectional diameter values at the same time. Since each measuring feature is measured on a reference at the same time, the measurement results are reliable. The pneumatic measuring head is made into a slender shape and can measure with high precision Slender inner hole.

4) The measuring method of the present invention is applicable to a wide range of measurements, can be detected on-line, does not need to put the workpiece into the measuring chamber, greatly improves the measuring efficiency, the method is simple and easy to operate, and has low technical requirements for workers.

Description of drawings

Fig. 1 is the structural representation of the device of the present invention;

Fig. 2 is the flow chart of the device measuring method of the present invention;

3 is a schematic diagram of the alignment of the straightness nozzle of the device of the present invention;

Fig. 4 is the calibration schematic diagram of the upper limit ring gauge of the taper nozzle of the device of the present invention;

Fig. 5 is the calibration schematic diagram of the lower limit ring gauge of the taper nozzle of the device of the present invention;

Fig. 6 is the schematic diagram of the device detection example of the present invention;

7 is a schematic diagram of the device of the present invention measuring an equal diameter curved hole;

8 is a schematic diagram of the device of the present invention measuring a conical hole;

FIG. 9 is a schematic diagram of the device of the present invention measuring a concave hole.

In the figure, trachea protective cover 1, spring 2, nut 3, handle 4, limit baffle 5, pneumatic measuring head 6, taper pneumatic nozzle 60, 61, 62, 63, straightness pneumatic nozzle 64, 65, 66, 67 , diversion groove 7, straightness upper limit calibration gauge 8, straightness lower limit calibration gauge 9, auxiliary calibration gauge 10, diameter upper limit calibration gauge 11, diameter lower limit calibration gauge 12, measured hole 13.

Detailed ways

The following are specific embodiments of the invention and combined with the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

The device of the present invention includes a pneumatic measuring assembly and its matching calibration gauge.

As shown in Figure 1, the pneumatic measuring assembly includes a trachea protective sleeve 1, a spring 2, a nut 3, a handle 4, a limit baffle 5 and a pneumatic measuring head 6; the tail end of the pneumatic measuring head 6 passes through the limit baffle 5 and the handle 4 The head end is connected, the handle 4 is a hollow structure, and the trachea protective sleeve 1 and the spring 2 are fixedly connected to the tail end of the handle 4 through a nut 3 .

As shown in Figure 1, there are four groups of taper pneumatic nozzles and four straightness pneumatic nozzles 64, 65, 66, 67 on the pneumatic measuring head 6. The four groups of taper pneumatic nozzles are divided into two groups, from the head end to the tail end. The four groups of taper pneumatic nozzles are 60, 61, 62, and 63 in sequence. The two taper pneumatic nozzles of each group are symmetrically arranged on both sides of the same cross section of the pneumatic measuring head 6, and the taper pneumatic nozzles of different groups are arranged on different pneumatic measuring heads 6. On the cross section, all the taper pneumatic nozzles are arranged on the same axial section of the pneumatic measuring head 6. The taper pneumatic nozzles of each group are connected to their respective pneumatic measuring instruments through their respective trachea, and the trachea passes through the handle 4 and the trachea protective sleeve 1. After connecting the pneumatic measuring instrument, the four groups of taper pneumatic nozzles form four-way taper pneumatic detection arranged at intervals along the axial direction.

Among the four straightness pneumatic nozzles 64, 65, 66, 67, two of the straightness pneumatic nozzles 64, 65 are arranged on the same side of the middle of the pneumatic measuring head 6, and the other two straightness pneumatic nozzles 66, 67 are respectively arranged in the pneumatic On the other side of the two ends of the measuring head 6, the four straightness pneumatic nozzles are arranged on the same axial section of the pneumatic measuring head 6, and the axial section where the straightness pneumatic nozzle is located is the same as the axial section where the taper pneumatic nozzle is located. Vertical, all straightness pneumatic nozzles are connected to the same pneumatic measuring instrument after passing through the same trachea. The trachea passes through the handle 4 and the tracheal protective sleeve 1 and then connects to the pneumatic measuring instrument, so that the four straightness pneumatic nozzles form a taper pneumatic detection. The outer side wall of the pneumatic measuring head 6 is provided with a plurality of guide grooves 7 along the axial direction, and the guide grooves 7 are arranged beside an exhaust dynamic nozzle along the axial direction and communicate with the annular groove of the pneumatic nozzle.

The matching calibration gauges include straightness upper limit calibration gauge 8, straightness lower limit calibration gauge 9, auxiliary calibration gauge 10, diameter upper limit calibration gauge 11 and diameter lower limit calibration gauge 12. The five calibration gauges are all collar structures, as shown in Figure 3～ 5 shown.

The cylindricity of the spool hole of the working valve body of the load-sensitive multi-way valve is taken as the detection object, and the cylindricity tolerance requirement is Δ=3μm. Three valve bodies a, b, and c are selected from a batch of valve bodies that have been processed, and are respectively tested according to the method of the present invention, and the process is shown in FIG. 2 . The embodiment of the present invention and its implementation process are as follows:

1) First calibrate the pneumatic nozzle: connect the pneumatic measuring component to the pneumatic measuring instrument, and adjust the magnification and zero point of the pneumatic measuring instrument.

As shown in Figure 3, calibrate the straightness measurement nozzle: fix the measuring head 6, set the upper limit calibration gauge 8, lower limit calibration gauge 9 and auxiliary calibration gauge 10 on the probe, at this time, the upper limit calibration gauge 8 covers the pneumatic nozzle 67. The auxiliary calibration gauge 10 covers the pneumatic nozzle 66, and the lower limit calibration gauge 9 covers the pneumatic nozzles 64 and 65 at the same time. Adjust the pneumatic gauge float to the lower limit position of the scale; then replace the upper and lower limit calibration gauges. At this time, the upper limit calibration gauge 8 covers the pneumatic nozzles 64 and 65 at the same time, and the pneumatic gauge buoy is adjusted to the upper limit position of the scale.

As shown in Figure 4 and Figure 5, calibrate the taper measuring nozzle: fix the measuring head 6, put the upper limit calibration gauge 11 on the measuring head, cover the pneumatic nozzle 63, and adjust the pneumatic measuring instrument float to the upper limit position of the scale ; Remove the upper limit calibration gauge 11, set the lower limit calibration gauge 12 on the measuring head 6, and adjust the pneumatic gauge buoy to the lower limit position of the scale; calibrate the pneumatic nozzles 60, 61, 62 according to the same method as above.

2) The composite measuring head measures the straightness error, roundness error and taper error synchronously:

As shown in Fig. 6, the composite measuring device is slowly put into the measured hole 13, and the limit baffle 5 is in contact with the outer end face of the inner hole 13, so that the pneumatic measuring head 6 and the measured hole 13 are axially overlapped and positioned, and then Rotate the pneumatic measuring head 6 360 degrees in a circle, measure the straightness, roundness and taper through five pneumatic measuring instruments in the following ways, record and obtain the measurement data of straightness, roundness and taper, specifically the straightness of the inner hole axis δ _A , the horizontal plane where the four groups of taper pneumatic nozzles are located. The inner hole roundness of the section δ _B , δ _C , δ _D , δ _E and the inner hole taper δ _F .

1) Record the diameter data of the pneumatic measuring instrument connected to the pneumatic nozzles 64, 65, 66, 67 in one revolution of the pneumatic measuring head 6, the maximum value minus the minimum value, take one half of the straightness of the inner hole axis delta _A. The measurement results of the straightness of the spool hole axis of the valve body a, b, and c are shown in Table 1.

Table 1 Measurement results of the straightness of the spool hole axis

valve body a valve body b valve body c Spool hole axis straightnessδ_A/μm 1.2 0.4 0.3

ii) Record the diameter data of the pneumatic gauges connected to each of the four taper pneumatic nozzles 60, 61, 62, and 63 in one rotation, and subtract the minimum value from the maximum value of all the diameter data of the same taper pneumatic nozzle, respectively. Obtain the inner hole roundness δ _B , δ _C , δ _D , and δ _E of the cross section where the four nozzles are located. According to the measurement methods shown in Figures 7 to 9, measure the roundness δ _B , δ of the four sections 1-1, 2-2, 3-3, 4-4 in the valve body a, b, and c spool holes, respectively _C , δ _D , δ _E , the measurement results are shown in Table 2.

Table 2 The roundness measurement results of different sections of the valve core hole

Ⅲ) Subtract the maximum value of the measured data recorded by the four taper pneumatic nozzles 60, 61, 62, 63 at the same rotation angle from the minimum value, and take 1/2 to obtain the difference, and take the measurement under different rotation angles in turn Make the same difference for the data, and take the maximum value of the difference after one rotation to obtain the inner hole taper δ _F . According to this measurement method, measure the taper of the valve body a, b, and c spool holes respectively, and obtain four groups of diameter measurement data (0-180°, 45-225°, 90-270°, 135-315°) (in pairs). The two angles are the rotation angles of the symmetrically arranged two taper pneumatic nozzles), and the taper of the valve core hole is obtained by calculation, and the measurement results are shown in Tables 3-5.

Table 3 Valve core hole taper measurement data and results of valve body a

Table 4 Valve core hole taper measurement data and results of valve body b

Table 5 Valve core hole taper measurement data and results of valve body c

3) The first qualification judgment based on the single largest error: the cylindricity error can be replaced by the synthesis of the shape error in the cross section of the measured cylindrical section and the axial section, the former is expressed by the roundness error, and the latter is expressed by the axis line Degree or prime line taper representation;

First find the maximum of all measurements

认为不符合公差要求，判定工件加工不合格；若

则作进一步判断。根据测量结果计算得到，阀体a阀芯孔的单项最大误差

阀体b阀芯孔的单项最大误差

阀体c阀芯孔的单项最大误差

均小于圆柱度公差要求Δ＝3μm，因此均需要进行下一步判断。The cylindricity tolerance requirement specified by the designer is Δ, if

It is considered that the tolerance requirements are not met, and the workpiece processing is judged to be unqualified; if

make further judgments. Calculated according to the measurement results, the single largest error of the valve body a spool hole

The single largest error of valve body b spool hole

The single largest error of valve body c spool hole

All are smaller than the cylindricity tolerance requirement Δ=3μm, so all need to be judged in the next step.

4) Calculate the average diameter of the four cross-sections of the inner hole:

Record the data of the pneumatic gauge connected to the taper pneumatic nozzle 60 at the proximal end of the measuring rod during one rotation, and obtain n diameter values d _P0-1 , d _P0-2 , , d _P0-n (n represents the measurement during one rotation times), and then calculate the average diameter d _P0 of the inner hole of the cross section where the nozzle is located; similarly, record the data of the pneumatic gauges connected to the remaining three groups of taper pneumatic nozzles 61, 62 and 63 in one rotation in turn, and obtain the average Diameters d _P1 , d _P2 , d _P3 . According to this measurement method, measure the average diameter d of the four sections 1-1, 2-2, 3-3, and 4-4 (as shown in Figures 7-9) in the valve body a, b, and c spool holes respectively. _P0 , d _P1 , d _P2 , d _P3 , and the average value d _P of the average diameters of the four cross-sections was calculated. The measurement results are shown in Table 6.

Table 6 The average diameter measurement results of different sections of the valve core hole

5) Automatic identification of hole shape based on the relationship between pore size:

Ⅰ) If |(d _P0 , d _P1 , d _P2 , d _P3 ) _{-d P} | Diameter bending hole (see Figure 7), otherwise make follow-up judgment;

Ⅱ) When d _P0 <(d _P1 , d _P2 )<d _P3 or d _P0 >(d _P1 , d _P2 )>d _P3 , one end of the inner hole is large and the other end is small, showing a tapered shape (see Figure 8), then is a tapered hole;

Ⅲ) When d _P0 <(d _P1 , d _P2 ) and d _P3 <(d _P1 , d _P2 ) or d _P0 >(d _P1 , d _P2 ) and d _P3 >(d _P1 , d _P2 ), the inner hole If the middle is large and the two sides are small, showing a convex shape, or the middle small and both ends are large, showing a concave shape (see Figure 9), it is a concave-convex hole;

IV) If none of the above-mentioned situations I, II or III are met, it is a hole of other shape.

In the embodiment, ε is taken as 0.2 μm. The results of the average diameter of the spool hole section of the valve body a do not conform to the above-mentioned cases I, II, and III, and belong to the case IV, and are judged as other shaped holes; the average diameter of the spool hole section of the valve body b satisfies d _P0 > (d _P1 , d _P2 ) and d _P3 >(d _P1 , d _P2 ), belonging to the case III, it is determined as a concave hole; the average diameter of the spool hole section of the valve body c satisfies d _P0 >(d _P1 , d _P2 )>d _P3 , belonging to the case II, is judged to be a tapered hole.

6) Calculation of adaptive cylindricity error value based on primary and secondary distinction:

Ⅰ) For the equal-diameter curved hole in Figure 7:

ii) For the tapered hole in Figure 8:

Ⅲ) For the concave-convex hole in Figure 9:

Ⅳ) Other shaped holes:

When the roundness error value is the largest:

When the roundness error value is not the maximum:

In the embodiment, the valve core hole of valve body a belongs to other shaped holes in case IV, and the largest single error is the axis straightness error δ _A = 1.2 μm, not the roundness error, so the valve core hole of valve body a is cylindrical The degree error is:

The spool hole of valve body b belongs to the concave hole of case III, and its cylindricity error is:

The spool hole of valve body c belongs to the conical hole of case II, and its cylindricity error is:

7) The second qualification judgment based on the measured cylindricity error: compare the obtained cylindricity error value δ with the cylindricity tolerance requirement Δ: when δ≤Δ, the workpiece is judged to be qualified; when δ>Δ, it is judged The workpiece is not up to standard. In the embodiment, the cylindricity errors of the valve core holes of valve bodies a, b, and c are all smaller than the cylindricity tolerance requirement Δ=3 μm, so the valve core holes of the three valve bodies a, b, and c selected are all judged as qualified cylindricity .

This embodiment specifically measures three slender valve core holes with a diameter of 15mm and a cylindricity tolerance of 3μm. For example, as shown in Table 7. In the embodiment, the maximum difference between the measurement results of the present invention and the cylindricity meter is 1.75-1.69=0.06 μm, while the minimum difference between the traditional taper approximate measurement and the measurement result of the cylindricity meter is 1.60-1.15=0.45 μm, which can be seen by comparison. The measurement result of the present invention has a higher approximation degree to the real cylindricity, the measurement accuracy is improved by an order of magnitude compared with the traditional measurement method using taper approximation, and the measurement result is more accurate.

Table 7 Accuracy comparison of measurement results of different cylindricity measurement methods

It can be seen that the present invention can effectively discriminate various inner hole shapes, has high precision and reliable results, is applicable to a wide range of working conditions, and can greatly improve the measurement efficiency.

The above embodiments should not be regarded as a limitation of the present invention, but any improvements made based on the spirit of the present invention should fall within the protection scope of the present invention.

Claims (8)

1. The utility model provides a pneumatic compound detection device of hole cylindricity of hole shape self-adaptation which characterized in that: the pneumatic measuring device comprises a pneumatic measuring component and a matched calibration gauge;

the pneumatic measuring component comprises an air pipe protective sleeve (1), a spring (2), a nut (3), a handle (4), a limiting baffle (5) and a pneumatic measuring head (6); pneumatic measuring head (6) tail end is connected with handle (4) head end through limit baffle (5), and trachea protective sheath (1) and spring (2) are through nut (3) fixed connection at handle (4) tail end, and it has eight tapering pneumatic nozzle and four straightness accuracy pneumatic nozzle (64, 65, 66, 67) to open on pneumatic measuring head (6), wherein:

the eight taper pneumatic nozzles form four groups of taper pneumatic nozzles (60, 61, 62 and 63) by taking two taper pneumatic nozzles as a group, the two taper pneumatic nozzles of each group are symmetrically arranged at two sides of the same cross section of the pneumatic measuring head (6), the taper pneumatic nozzles of different groups are arranged on different cross sections of the pneumatic measuring head (6), all the taper pneumatic nozzles are arranged on the same axial cross section of the pneumatic measuring head (6), the taper pneumatic nozzles of each group are connected with respective pneumatic measuring instruments after passing through respective air pipes, and the air pipes are connected with the pneumatic measuring instruments after passing through the handle (4) and the air pipe protective sleeve (1);

Among the four straightness pneumatic nozzles (64, 65, 66, 67), two of the straightness pneumatic nozzles are arranged on the same side of the middle part of the pneumatic measuring head (6), the other two straightness pneumatic nozzles are respectively arranged on the other sides of the two end parts of the pneumatic measuring head (6), the four straightness pneumatic nozzles are all arranged on the same axial section of the pneumatic measuring head (6), the axial section where the straightness pneumatic nozzles are arranged is vertical to the axial section where the taper pneumatic nozzles are arranged, all the straightness pneumatic nozzles are connected with the same pneumatic measuring instrument after passing through the same air pipe, and the air pipe passes through the handle (4) and the air pipe protective sleeve (1) and then is connected with the pneumatic measuring instrument.

2. The hole-shaped adaptive inner hole cylindricity pneumatic composite detection device according to claim 1, characterized in that: the matched calibration gauge comprises a linearity upper limit calibration gauge (8), a linearity lower limit calibration gauge (9), an auxiliary calibration gauge (10), a diameter upper limit calibration gauge (11) and a diameter lower limit calibration gauge (12), and the five calibration gauges are of lantern ring structures.

3. The hole-shaped adaptive inner hole cylindricity pneumatic composite detection device according to claim 1, characterized in that: pneumatic measuring head (6) lateral wall be equipped with a plurality of axial guiding gutter (7) of following, guiding gutter (7) set up along the axial one row pneumatic nozzle next door and with the pneumatic nozzle annular communicates with each other.

4. The hole-shaped adaptive inner hole cylindricity pneumatic composite detection device according to claim 1, characterized in that: the straightness pneumatic nozzle and the taper pneumatic nozzle are arranged on the pneumatic measuring head (6) at the same time, and various shape errors of the inner hole are measured at the same time to obtain the cylindricity.

5. A hole-shape adaptive inner hole cylindricity pneumatic composite measuring method is characterized in that the composite detecting device of any one of claims 1-4 is used, and the following steps are adopted:

1) and (3) calibrating a pneumatic nozzle: respectively calibrating a straightness measuring nozzle and a taper measuring nozzle on the pneumatic measuring head (6);

2) and (3) synchronously measuring straightness error, roundness error and taper error: the composite detection device is placed into a hole (13) to be detected, and the limit baffle (5) is contacted with the outer end surface of the inner hole (13), so that the pneumatic measuring head (6) and the hole (13) to be detected are axially overlapped and positioned, and thenThe pneumatic measuring head (6) is rotated for 360 degrees in a circle, the measurement is carried out by the following method through the pneumatic measuring instrument, and the measurement data of the straightness, the roundness and the taper, specifically the straightness delta of the axis of the inner hole, are recorded and obtained_AInner hole roundness delta of cross section where four groups of taper pneumatic nozzles are located_B、δ_C、δ_D、δ_EAnd bore taper delta _F；

3) Judging the first qualification: the following formula is used to find the maximum value in all the measured data

And will maximum value

Compared with the cylindricity tolerance requirement delta if

The tolerance requirement is not met, and the inner hole of the workpiece is unqualified; if it is

Continuing to the next step;

4) measuring and obtaining the average diameter of cross sections of four positions of the inner hole, and obtaining the hole shape of the inner hole through the average diameter of the cross sections of the four positions;

5) adopting a primary distinguishing mode and a secondary distinguishing mode to carry out self-adaptive cylindricity calculation to obtain a cylindricity error value delta;

6) and (3) second qualification judgment: comparing the cylindricity error value delta with the cylindricity tolerance requirement delta again, and when delta is less than or equal to delta, determining that the inner hole of the workpiece is qualified for machining; and when delta is larger than delta, the inner hole of the workpiece is not processed.

6. The hole-shape adaptive inner hole cylindricity pneumatic composite measuring method according to claim 5, characterized in that: the step 2) is specifically as follows:

i) straightness

In the process that the pneumatic measuring head (6) rotates for one circle, diameter data collected by a pneumatic measuring instrument connected with the pneumatic nozzle for straightness is recorded in real time, the maximum value collected is subtracted from the minimum value, and one half of the difference value after subtraction is taken as the straightness delta of the inner hole axis _A；

II) roundness

In the process that the pneumatic measuring head (6) rotates for one circle, diameter data acquired by pneumatic measuring instruments respectively connected with the four groups of taper pneumatic nozzles are respectively recorded, the difference value obtained by subtracting the minimum value from the maximum value in the diameter data of the same taper pneumatic nozzle is used as the roundness of the inner hole, and therefore the roundness delta of the inner hole of the cross section where the four groups of taper pneumatic nozzles are located is respectively obtained_B、δ_C、δ_D、δ_E；

III) taper

Subtracting the minimum value from the maximum value in the diameter data of the four groups of taper pneumatic nozzles of the pneumatic measuring head (6) at a fixed rotation angle, taking one half to obtain a difference value, then measuring the pneumatic measuring head (6) in the process of rotating for one circle, and taking the maximum value of the difference value in all the rotation angle positions as the taper delta of the inner hole_F。

7. The hole-shape adaptive inner hole cylindricity pneumatic composite measuring method according to claim 5, characterized in that: the step 4) is specifically as follows:

4.1) measuring and calculating the average diameter of the cross section of the inner hole at four positions:

aiming at four groups of tapered pneumatic nozzles (60, 61, 62 and 63) of a pneumatic measuring head (6), all diameter data in one rotation of the pneumatic measuring head (6) are acquired by respective pneumatic measuring instruments, and the average value is taken as the average diameter of an inner hole of the cross section where the tapered pneumatic nozzle is located, so that the average diameter d of the cross section at four positions is obtained _P0、d_P1、d_P2And d_P3And calculating the average value d of the average diameters of the four cross sections_P＝(d_P0+d_P1+d_P2+d_P3)/4；

4.2) judging the pore shape based on the pore size relation:

i) if (d)_P0、d_P1、d_P2、d_P3)-d_PI | ≦ ε, i.e. the average diameter of the cross-section at four locations and d_PIf the deviation is not more than the set threshold value epsilon, the hole is an equal-diameter bent hole, otherwise, subsequent judgment is made;

II) if d is satisfied_P0<(d_P1、d_P2)<d_P3Or d_P0>(d_P1、d_P2)>d_P3If the hole is a tapered hole;

III) if d is satisfied_P0<(d_P1、d_P2) And d is_P3<(d_P1、d_P2) Or satisfy d_P0>(d_P1、d_P2) And d is_P3>(d_P1、d_P2) Then the holes are concave-convex holes;

IV) if none of the above I, II or III is met, then the wells are other wells.

8. The hole-shape adaptive inner hole cylindricity pneumatic composite measuring method according to claim 5, characterized in that: the step 5) is specifically to calculate and obtain cylindricity error values aiming at the constant diameter curved hole, the tapered hole, the concave-convex hole and other holes by adopting the following modes:

i) calculating the equal-diameter bent hole by adopting the following formula to obtain a cylindricity error value delta:

II) calculating the cylindricity error value delta by adopting the following formula:

III) calculating the cylindricity error value delta by adopting the following formula:

IV) calculating other holes by adopting the following formula to obtain a cylindricity error value delta;

when the roundness error value is maximum:

when the roundness error value is not maximum:

Wherein, delta_ARepresenting bore axis straightness, delta_B、δ_C、δ_D、δ_EInner hole roundness, delta, of cross section where four groups of taper pneumatic nozzles are respectively arranged_FIndicating the bore taper.

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