CN106705900A - Hole form adaptive bore cylindricity pneumatic composite detection device and measuring method - Google Patents

Abstract

The invention discloses a hole shape self-adapting inner hole cylindricity pneumatic compound detection device and a measuring method. Including pneumatic measuring components and their matching calibration gauges, there are four sets of taper pneumatic nozzles and four straightness pneumatic nozzles on the pneumatic measuring head; the pneumatic nozzles are calibrated first, and then the straightness error, roundness error and taper error are measured synchronously. Then carry out the first qualification judgment, measure the average diameter of the four cross-sections of the inner hole, and obtain the hole shape of the inner hole through the average diameter of the four cross-sections, and use the primary and secondary distinction method to carry out adaptive cylindricity calculation to obtain the cylindricity Error value, and finally the second eligibility judgment. The composite pneumatic detection device and measurement method disclosed in the present invention can effectively distinguish various inner hole shapes, and calculate the cylindricity with an adaptive algorithm, have high measurement accuracy, reliable measurement results, wide range of applicable working conditions, and can realize on-site inspection of workpieces. detection, greatly improving measurement efficiency.

Description

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

Technical Field

The invention relates to an inner hole precision detection device and a measuring method, in particular to a hole shape self-adaptive inner hole cylindricity pneumatic composite detection device and a measuring method aiming at the field detection of a precision fit inner hole.

Background

The machining precision of the precision fit inner hole is a key factor for determining the performance of certain parts. The inner hole cylindricity error is an important performance index for ensuring the matching precision. The cylindricity error of the precise matching hole is required by designers to be only a few micrometers, and the inner hole is mostly slender, so that the detection of the cylindricity of the inner hole becomes increasingly difficult.

At present, the detection of the cylindricity of an inner hole of a product in the market mainly comprises a traditional pneumatic measuring instrument detection method, a roundness measuring instrument method and a three-coordinate measuring machine method. The traditional pneumatic detection is used for replacing cylindricity by detecting a certain single shape error of an inner hole, such as straightness or taper, obviously, the measurement method is difficult to adapt to different hole shapes, the evaluation result and the real cylindricity have large errors, and the measurement requirement is difficult to meet. In addition, the method replaces cylindricity by single shape error, and has less information of inner holes and poor representativeness.

Liuhui construction and the like in the patent of 'comprehensive detection device and test method for steering gear rack precision value (201610025563.5)', the cylindricity is calculated by using the diameter range, the jumping range and the straightness numerical value of the measured slender rod piece. The straightness can be measured by using the guide rail in the device, so that a large error can be introduced, and when the precision reaches a micron level, the measurement is difficult to be accurate. In addition, there is no detailed formula for calculating cylindricity.

The roundness measuring method and the three-coordinate measuring machine method are most accurate in detecting the cylindricity of the inner hole, but the detection is required in a special metering chamber, the detection steps are complex, the period is long, the cost is high, and the method is not suitable for detecting mass products and cannot be used for detecting in a production field. Especially, when the inner hole which needs to be corrected repeatedly is detected, the detection period is long, so that the production efficiency is very low.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, and provides a hole-shape-adaptive inner hole cylindricity pneumatic composite detection device and a measurement method.

The technical scheme adopted by the invention is as follows:

a pneumatic compound detection device of hole shape self-adaptation hole cylindricity:

comprises a pneumatic measuring component and a matched calibration gauge.

The pneumatic measuring component comprises an air pipe protective sleeve, a spring, a nut, a handle, a limiting baffle and a pneumatic measuring head; the tail end of the pneumatic measuring head is connected with the head end of the handle through the limiting baffle, the limiting baffle is used for being connected to the end face of the hole to be positioned, the handle is of a hollow structure, and the air pipe protective sleeve and the spring are fixedly connected to a nut at the tail end of the handle through nuts.

The pneumatic measuring head is provided with four groups of taper pneumatic nozzles and four straightness pneumatic nozzles, wherein: the four groups of taper pneumatic nozzles are divided into two groups, the two taper pneumatic nozzles of each group are symmetrically arranged on two sides of the same cross section of the pneumatic measuring head, the taper pneumatic nozzles of different groups are arranged on different cross sections of the pneumatic measuring head, all the taper pneumatic nozzles are arranged on the same axial cross section of the pneumatic measuring head, the taper pneumatic nozzles of each group are connected with respective pneumatic measuring instruments after passing through respective air pipes, and the air pipes penetrate through a handle and an air pipe protective sleeve and are connected with the pneumatic measuring instruments, so that the four groups of taper pneumatic nozzles form four paths of taper pneumatic detection which are arranged at intervals along the axial direction; among the four straightness pneumatic nozzles, two of the straightness pneumatic nozzles are arranged on the same side of the middle of the pneumatic measuring head, the other two straightness pneumatic nozzles are respectively arranged on the other sides of two ends of the pneumatic measuring head, the four straightness pneumatic nozzles are all arranged on the same axial section of the pneumatic measuring head, the axial section where the straightness pneumatic nozzles are located is perpendicular to the axial section where the conicity pneumatic nozzles are located, all the straightness pneumatic nozzles are connected with the same pneumatic measuring instrument after passing through the same air pipe, the air pipe penetrates through the handle and the air pipe protective sleeve and then is connected with the pneumatic measuring instrument, and therefore the four straightness pneumatic nozzles form one path of conicity pneumatic detection.

The matched calibration gauge comprises a linearity upper limit calibration gauge, a linearity 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 of lantern ring structures.

The lateral 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 a row of pneumatic nozzles along the axial direction and are communicated with the pneumatic nozzle ring grooves.

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

Secondly, a hole-shape self-adaptive inner hole cylindricity pneumatic composite measuring method comprises the following steps:

1) and (3) calibrating a pneumatic nozzle: respectively calibrating a straightness measuring nozzle and a taper measuring nozzle on a pneumatic measuring head, calibrating the straightness measuring nozzle by using a straightness upper limit calibration gauge, a straightness lower limit calibration gauge and an auxiliary calibration gauge, and calibrating the taper measuring nozzle by using a diameter upper limit calibration gauge and a diameter lower limit calibration gauge;

2) and (3) synchronously measuring straightness error, roundness error and taper error:

the composite measuring device is placed into a hole to be measured, the limiting baffle is in contact with the outer end face of the inner hole, the pneumatic measuring head and the hole to be measured are axially overlapped and positioned, then the pneumatic measuring head is rotated for 360 degrees in a circle, the five pneumatic measuring instruments are used for measuring in the following mode, and measuring data of straightness, roundness and taper, specifically inner hole axis straightness, are obtained through recording_AInner hole roundness of cross section of four groups of taper pneumatic nozzles_B、_C、_D、_EAnd bore taper_F(ii) a The data obtained by measuring the pneumatic nozzle on the pneumatic measuring instrument is the diameter data of the position of the pneumatic nozzle.

3) Judging the first qualification: the maximum value among all the measured data is found by using the following formula

And will maximize the valueCompared with the cylindricity tolerance requirement delta ifThe tolerance requirement is not met, and the inner hole of the workpiece is unqualified; if it isContinuing 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;

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

The step 2) is specifically as follows:

i) straightness: in the process that the pneumatic measuring head 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 and the minimum value are subtracted from the collected maximum value, and one half of the difference value after subtraction is taken as the straightness of the axis of the inner hole_A；

II) roundness: in the process of one rotation of the pneumatic measuring head, diameter data acquired by the pneumatic measuring instruments respectively connected with the four groups of taper pneumatic nozzles are respectively recorded, and the same taper pneumatic nozzle is usedThe difference value of the maximum value minus the minimum value in the diameter data is used as the roundness of the inner hole, and the roundness of the inner hole of the cross section where the four groups of taper pneumatic nozzles are located is obtained respectively_B、_C、_D、_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 when the pneumatic measuring head is at a fixed rotation angle, taking one half to obtain a difference value, measuring the pneumatic measuring head 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 of the inner hole_F。

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 taper pneumatic nozzles of a pneumatic measuring head, all diameter data in one rotation of the pneumatic measuring head are acquired by respective pneumatic measuring instruments, and an average value is taken as the average diameter of an inner hole of a cross section where the taper pneumatic nozzle is located, so that the average diameters d of the cross sections at four positions are sequentially 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_P| ≦ (i.e. average diameter of cross-section at four places and d)_PThe deviation is not more than the set threshold value), the hole is an equal-diameter bent hole, otherwise, subsequent judgment is carried out;

II) if d is satisfied_P0<(d_P1、d_P2)<d_P3Or d_P0>(d_P1、d_P2)>d_P3One end of the inner hole is large, the other end is small, and the inner hole is conical;

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) The middle of the inner hole is large and the two sides are small and convex, or the middle of the inner hole is small and the two ends are large and concave and are concave-convex holes;

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

And 5) specifically, calculating to obtain cylindricity error values aiming at the equal-diameter bent holes, the tapered holes, the concave-convex holes and other holes by adopting the following modes:

i) calculating the constant-diameter bent hole by adopting the following formula to obtain a cylindricity error value, wherein an axis straightness error in an axial section is a main component of the constant-diameter bent hole cylindricity error, a roundness error in the cross section is a secondary component, and the cylindricity error is the integration of the axis straightness error and the roundness error:

II) calculating the conical hole by adopting the following formula to obtain a cylindricity error value, wherein the taper error in the axial section is a main component of the cylindricity error of the conical hole, the roundness error in the cross section is a secondary component, and the cylindricity error is the combination of the taper error and the roundness error:

III) calculating to obtain a cylindricity error value by adopting the following formula, wherein the taper error in the axial section is a main component of the cylindricity error of the concave-convex hole, the roundness error in the cross section is a secondary component, and the cylindricity error is the combination of the taper error and the roundness error:

IV) calculating other holes by adopting the following formula to obtain cylindricity error values, wherein the cylindricity error value is obtained by adding a half of the maximum value in the section where the maximum value is not located to the maximum value in the roundness error value, the taper error value and the straightness error value, and the two numerical values forming the cylindricity error value are respectively taken as error values in two sections of the cross section and the axial cross section;

when the roundness error value is maximum:

when the roundness error value is not maximum:

wherein,_Athe straightness of the axis of the inner hole is shown,_B、_C、_D、_Ethe roundness of the inner hole of the cross section of each group of tapered pneumatic nozzles,_Findicating the bore taper.

The cross-sections to which the present invention relates include axial cross-sections parallel to the axial direction and cross-sections perpendicular to the axial direction.

When the pneumatic detection device finishes measurement, the cylindricity error is calculated by integrating the measured straightness error, roundness error and taper error according to the result of the hole shape self-adaptive judgment.

The invention has the following advantages:

1) the device is a high-precision and composite type pneumatic detection device for the cylindricity of the slender inner hole with the hole shape self-adaptive characteristic. The traditional pneumatic measurement assembly can only measure a single roundness error value, a single straightness error value and the like to replace cylindricity. The device of the invention calculates the cylindricity error by utilizing the straightness error value, the roundness error value and the taper error value which are measured simultaneously, can better approach the theoretical cylindricity, and greatly improves the measurement accuracy.

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

The combined measuring head disclosed by the invention can simultaneously measure the straightness error, the roundness error and the taper error, and calculates the cylindricity by using the self-adaptive cylindricity algorithm based on the primary and secondary distinguishing modes, so that the combined measuring head has the self-adaptive characteristic to the hole shape, and the problem that one measuring head can only measure part of special holes is well solved.

3) When the traditional pneumatic measurement assembly approximately replaces the cylindricity error value through the taper, the measuring heads measure in a single-layer step-by-step mode, and the axes of the measuring heads at various measuring positions cannot be coincided when the measuring heads are pulled, so that errors are caused. The pneumatic measuring head is made into a slender shape, and can measure slender inner holes with high precision.

4) The measuring method has wide application and measuring range, can carry out on-line in-situ detection, does not need to put the workpiece into a measuring chamber, greatly improves the measuring efficiency, and has simple and easy operation and low technical requirement on workers.

Drawings

FIG. 1 is a schematic diagram of the apparatus of the present invention;

FIG. 2 is a flow chart of a measurement method of the apparatus of the present invention;

FIG. 3 is a schematic view of the alignment of a straightness nozzle of the apparatus of the present invention;

FIG. 4 is a schematic view of the upper limit gauge calibration of the tapered nozzle of the apparatus of the present invention;

FIG. 5 is a schematic view of the lower limit gauge calibration of the tapered nozzle of the apparatus of the present invention;

FIG. 6 is a schematic view of an exemplary testing apparatus according to the present invention;

FIG. 7 is a schematic view of the apparatus of the present invention for measuring an isometric curved hole;

FIG. 8 is a schematic view of the apparatus of the present invention measuring a tapered hole;

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

In the figure, an air pipe protective sleeve 1, a spring 2, a nut 3, a handle 4, a limit baffle 5, a pneumatic measuring head 6, taper pneumatic nozzles 60, 61, 62 and 63, straightness pneumatic nozzles 64, 65, 66 and 67, a diversion trench 7, a straightness upper limit calibration gauge 8, a straightness lower limit calibration gauge 9, an auxiliary calibration gauge 10, a diameter upper limit calibration gauge 11, a diameter lower limit calibration gauge 12 and a measured hole 13 are arranged.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

The device comprises a pneumatic measuring assembly and a calibration gauge matched with the pneumatic measuring assembly.

As shown in fig. 1, the pneumatic measuring assembly comprises an air pipe 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 is connected with the head end of the handle 4 through the limiting baffle 5, the handle 4 is of a hollow structure, and the air pipe protective sleeve 1 and the spring 2 are fixedly connected at the tail end of the handle 4 through the nut 3.

As shown in fig. 1, four sets of taper pneumatic nozzles and four straightness pneumatic nozzles 64, 65, 66, 67 are arranged on the pneumatic measuring head 6, two of the four sets of taper pneumatic nozzles are in one set, the four sets of taper pneumatic nozzles from the head end to the tail end are 60, 61, 62, 63 in sequence, the two taper pneumatic nozzles of each set are symmetrically arranged on two sides of the same cross section of the pneumatic measuring head 6, the taper pneumatic nozzles of different sets 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 set are connected with respective pneumatic measuring instruments through respective air pipes, the air pipes penetrate through the handle 4 and the air pipe protective sleeve 1 and then are connected with the pneumatic measuring instruments, and therefore four sets of taper pneumatic nozzles form four paths of taper pneumatic detection arranged at intervals along the axial direction.

Among the four straightness pneumatic nozzles 64, 65, 66 and 67, two of the straightness pneumatic nozzles 64 and 65 are arranged on the same side of the middle of the pneumatic measuring head 6, the other two straightness pneumatic nozzles 66 and 67 are respectively arranged on the other sides of two ends 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 located is perpendicular to the axial section where the taper pneumatic nozzles are located, all the straightness pneumatic nozzles are connected with the same pneumatic measuring instrument after passing through the same air pipe, the air pipe passes through the handle 4 and the air pipe protective sleeve 1 and then is connected with the pneumatic measuring instrument, and therefore the four straightness pneumatic nozzles form one-path taper pneumatic detection. The outer side wall of the pneumatic measuring head 6 is provided with a plurality of axial guide grooves 7, and the guide grooves 7 are arranged beside an axial row of pneumatic nozzles and communicated with the pneumatic nozzle ring grooves.

The matched calibration gauge comprises an upper linearity calibration gauge 8, a lower linearity calibration gauge 9, an auxiliary calibration gauge 10, an upper diameter calibration gauge 11 and a lower diameter calibration gauge 12, and the five calibration gauges are of lantern ring structures and are shown in figures 3-5.

The cylindricity of a valve core hole of a working valve body of the load-sensitive multi-way valve is used as a detection object, and the tolerance requirement of the cylindricity is 3 mu m. Three valve bodies a, b and c are selected from a batch of valve bodies which are processed, and are respectively detected according to the method, and the flow is shown in figure 2. The embodiment of the invention and the implementation process thereof are as follows:

1) firstly, carrying out pneumatic nozzle calibration: and connecting the pneumatic measuring assembly with a pneumatic measuring instrument, and adjusting the multiplying power and the zero point of the pneumatic measuring instrument.

As shown in fig. 3, a calibration straightness measuring nozzle was performed: fixing the measuring head 6, sleeving the upper limit calibration gauge 8, the lower limit calibration gauge 9 and the auxiliary calibration gauge 10 on the measuring head, covering the pneumatic nozzle 67 by the upper limit calibration gauge 8, covering the pneumatic nozzle 66 by the auxiliary calibration gauge 10, covering the pneumatic nozzles 64 and 65 by the lower limit calibration gauge 9, and adjusting the buoy of the pneumatic measuring instrument to the lower limit position of the graduated scale; and then the upper and lower limit calibration gauges are sleeved on the measuring head in a replacement mode, at the moment, the upper limit calibration gauge 8 covers the pneumatic nozzles 64 and 65 at the same time, and the buoy of the pneumatic measuring instrument is adjusted to the upper limit position of the graduated scale.

As shown in fig. 4 and 5, the taper measuring nozzle was calibrated: fixing the measuring head 6, sleeving the upper limit calibration gauge 11 on the measuring head, covering the pneumatic nozzle 63, and adjusting the buoy of the pneumatic measuring instrument to the upper limit position of the graduated scale; taking down the upper limit calibration gauge 11, sleeving the lower limit calibration gauge 12 on the measuring head 6, and adjusting the buoy of the pneumatic measuring instrument to the lower limit position of the graduated scale; the pneumatic nozzles 60, 61, 62 are calibrated in the same way as described above.

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

as shown in fig. 6, the composite measuring device is slowly placed into the hole 13 to be measured, 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 hole 13 to be measured are axially positioned in an overlapping manner, then the pneumatic measuring head 6 is rotated for a circle 360 degrees, the five pneumatic measuring instruments are used for measuring in the following manner, and measuring data of straightness, roundness and taper, specifically the straightness of the axis of the inner hole, are recorded and obtained_AInner hole roundness of cross section of four groups of taper pneumatic nozzles_B、_C、_D、_EAnd bore taper_F。

I) pneumatic gauge to which pneumatic nozzles 64, 65, 66, 67 are connected for recording straightnessThe diameter data of the measuring head 6 in one rotation is obtained by subtracting the minimum value from the maximum value and taking one half of the minimum value to obtain the straightness of the axis of the inner hole_A. The valve core hole axis straightness measurement results of the valve bodies a, b and c are shown in table 1.

TABLE 1 valve core hole axis straightness measurement results

	Valve body a	Valve body b	Valve body c
				Spool bore axis straightness δA/μm	1.2	0.4	0.3

II) respectively recording the diameter data of the pneumatic measuring instrument respectively connected with the four taper pneumatic nozzles 60, 61, 62 and 63 in one rotation, subtracting the minimum value from the maximum value in all the diameter data of the same taper pneumatic nozzle, and respectively obtaining the roundness of the inner hole of the cross section where the four nozzles are positioned_B、_C、_D、_E. According to the measuring modes shown in FIGS. 7-9, the roundness of four sections 1-1, 2-2, 3-3 and 4-4 in the valve core holes of the valve bodies a, b and c is measured respectively_B、_C、_D、_EThe measurement results are shown in table 2.

TABLE 2 roundness measurement results of different cross-sections of spool bore

III) subtracting the minimum value from the maximum value of the measurement data recorded by the four taper pneumatic nozzles 60, 61, 62 and 63 at the same rotation angle, taking one half to obtain a difference value, sequentially taking the measurement data at different rotation angles to make the same difference value, taking the maximum value of the difference value after rotating for one circle to obtain the taper of the inner hole_F. According to the measuring mode, the conicity of the valve core holes of the valve bodies a, b and c is measured respectively, four groups of diameter measuring data (two paired angles are the rotating angles of two conicity pneumatic nozzles which are symmetrically arranged) of 0-180 degrees, 45-225 degrees, 90-270 degrees and 135-315 degrees are obtained, the conicity of the valve core hole is obtained through calculation, and the measuring results are shown in tables 3-5.

TABLE 3 valve core hole taper measurement data and results for 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) First eligibility judgment based on single maximum error: the cylindricity error can be replaced by the combination of the shape error in the cross section and the axial section of the measured cylindrical surface, wherein the cylindricity error is expressed by a roundness error, and the cylindricity error is expressed by axial straightness or plain line taper;

first find the maximum of all the measured values

The cylindricity tolerance requirement specified by the designer is Δ ifJudging that the workpiece is not qualified in machining if the workpiece does not meet the tolerance requirement; if it isA further determination is made. According to the measurement result, the single maximum error of the valve core hole of the valve body a is calculatedSingle maximum error of valve core hole of valve body bSingle maximum error of valve core hole of valve body cAll are less than the cylindricity tolerance requirement delta 3 mu m, so all need to be judged in the next step.

4) Calculating the average diameter of cross sections of the inner hole:

recording the data of the pneumatic measuring instrument connected with the taper pneumatic nozzle 60 at the nearest end of the measuring rod in one rotation to obtain n diameter values d_P0-1，d_P0-2，，，d_P0-n(n represents in one revolution)Number of measurements) to calculate the average diameter d of the inner bore of the cross section of the nozzle_P0(ii) a Similarly, the data of the air gauge connected to the remaining three sets of tapered air nozzles 61, 62 and 63 are recorded in sequence during one revolution, and the average diameter d is obtained_P1、d_P2、d_P3. According to the measuring mode, the average diameter d of four sections 1-1, 2-2, 3-3 and 4-4 (shown in figures 7-9) in the valve core holes of the valve bodies a, b and c is measured respectively_P0、d_P1、d_P2、d_P3And calculating to obtain the average value d of the average diameters of the cross sections at four positions_PThe measurement results are shown in Table 6.

TABLE 6 average diameter measurement of different sections of spool bore

5) And (3) automatically distinguishing the hole shape based on the relation of the hole diameter and the size:

i) if (d)_P0、d_P1、d_P2、d_P3)-d_P| ≦ (i.e. average diameter of cross-section at four places and d)_PThe deviation is not more than the set threshold value), the inner hole is an equal-diameter bent hole (see figure 7), otherwise, subsequent judgment is made;

II) when d_P0<(d_P1、d_P2)<d_P3Or d_P0>(d_P1、d_P2)>d_P3When the hole is large, one end of the inner hole is small, and the inner hole is a conical hole (see figure 8);

III) when d_P0<(d_P1、d_P2) And d is_P3<(d_P1、d_P2) Or d_P0>(d_P1、d_P2) And d is_P3>(d_P1、d_P2) When the inner hole is large in the middle and small in two sides, the inner hole is convex, or the inner hole is small in the middle and large in two ends, the inner hole is concave (see figure 9), and the inner hole is a concave-convex hole;

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

In the examples, 0.2 μm was used. The average diameter result of the cross section of the valve core hole of the valve body a does not accord with the situations I, II and III, belongs to the situation IV, and is judged to be other holes; d is satisfied by the average diameter result of the valve core hole section of the valve body b_P0>(d_P1、d_P2) And d is_P3>(d_P1、d_P2) (iv) case iii, judged as a concave cell; d is satisfied by the average diameter result of the valve core hole section of the valve body c_P0>(d_P1、d_P2)>d_P3And belongs to case II, the hole is determined to be a tapered hole.

6) Calculating the self-adaptive cylindricity error value based on the primary and secondary distinguishing modes:

i) for the constant diameter curved hole of fig. 7:

ii) for the tapered hole of fig. 8:

iii) for the concave-convex hole of fig. 9:

IV) other wells:

when the roundness error value is maximum:

when the roundness error value is not maximum:

in the embodiment, the valve core hole of the valve body a belongs to other holes in the case IV, and the single error is the largest axis straightness error_A1.2 μm, not the roundness error, so the spool bore cylindricity error of valve body a is:

the valve core hole of the valve body b belongs to a concave hole of the case III, and the cylindricity error is as follows:

the case hole of valve body c belongs to the bell mouth of situation II, and its cylindricity error is:

7) and (3) judging the second pass based on the measured cylindricity error: comparing the obtained cylindricity error value with the cylindricity tolerance requirement delta: when the value is less than or equal to delta, judging that the workpiece is qualified for machining; and when the value is larger than delta, judging that the workpiece is not processed successfully. In the embodiment, the cylindricity errors of the valve core holes of the valve bodies a, b and c are all smaller than the cylindricity tolerance requirement delta of 3 μm, so that the valve core holes of the three selected valve bodies a, b and c are judged to be qualified in cylindricity.

This example is specifically to measure three elongated spool holes with a diameter of 15mm and a cylindricity tolerance of 3 μm, and compare the measurement results with those of the measurement method using taper approximation and the measurement method using cylindricity meter, and the comparison of the measurement results is shown in table 7. In the embodiment, the maximum difference value between the measurement result of the taper approximate measurement method and the measurement result of the cylindricity instrument is 1.75-1.69-0.06 μm, while the minimum difference value between the measurement result of the taper approximate measurement method and the measurement result of the cylindricity instrument is 1.60-1.15-0.45 μm, and the comparison shows that the approximation degree between the measurement result of the taper approximate measurement method and the true cylindricity is higher, the measurement precision is improved by one order of magnitude compared with the traditional measurement method adopting taper approximate, and the measurement result is more accurate.

TABLE 7 comparison of the accuracy of the measurement results of different cylindricity measurement methods

Therefore, the invention can effectively distinguish various inner hole shapes, has high precision and reliable result, has wide working condition application range and can greatly improve the measurement efficiency.

The above examples should not be construed as limiting the present invention, but any modifications made based on the spirit of the present invention should be within the scope of protection 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 all 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 measuring 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 measuring device is placed in a measured hole (13), the limiting baffle (5) is in contact with the outer end face of the inner hole (13), the pneumatic measuring head (6) and the measured hole (13) are axially overlapped and positioned, then the pneumatic measuring head (6) is rotated for 360 degrees in a circle, measurement data of straightness, roundness and taper are obtained through recording by the pneumatic measuring instrument in the following mode, and the measurement data are specifically the straightness of the axis of the inner hole_AInner hole roundness of cross section of four groups of taper pneumatic nozzles_B、_C、_D、_EAnd bore taper_F；

3) Judging the first qualification: the maximum value among all the measured data is found by using the following formula

And will maximize the valueCompared with the cylindricity tolerance requirement delta ifThe tolerance requirement is not met, and the inner hole of the workpiece is unqualified; if it isContinuing 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;

6) and (3) second qualification judgment: comparing the cylindricity error value with the cylindricity tolerance requirement delta again, and when the cylindricity error value is less than or equal to delta, determining that the inner hole of the workpiece is qualified for machining; and when the value 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 of the axis of the inner hole_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, and 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, so that the roundness of the inner hole of the cross section where the four groups of taper pneumatic nozzles are located is respectively obtained_B、_C、_D、_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 all the rotation anglesThe maximum value of the difference in position is taken as the bore taper_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_P| ≦ (i.e. average diameter of cross-section at four places and d)_PThe deviation is not more than the set threshold value), the hole is an equal-diameter bent hole, otherwise, subsequent judgment is carried out;

II) if d is satisfied_P0<(d_P1、d_P2)<d_P3Or d_P0>(d_P1、d_P2)>d_P3Then 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:

and 5) specifically, calculating to obtain cylindricity error values aiming at the equal-diameter bent holes, the tapered holes, the concave-convex holes 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:

$\mathrm{\&delta;}={\mathrm{\&delta;}}_A+\frac{1}{2}Max\{{\mathrm{\&delta;}}_B,{\mathrm{\&delta;}}_C,{\mathrm{\&delta;}}_D,{\mathrm{\&delta;}}_E\}$

II) calculating the conical hole by adopting the following formula to obtain a cylindricity error value:

$\mathrm{\&delta;}={\mathrm{\&delta;}}_F+\frac{1}{2}Max\{{\mathrm{\&delta;}}_B,{\mathrm{\&delta;}}_C,{\mathrm{\&delta;}}_D,{\mathrm{\&delta;}}_E\}$

III) calculating the concave-convex hole by adopting the following formula to obtain a cylindricity error value:

$\mathrm{\&delta;}={\mathrm{\&delta;}}_F+\frac{1}{2}Max\{{\mathrm{\&delta;}}_B,{\mathrm{\&delta;}}_C,{\mathrm{\&delta;}}_D,{\mathrm{\&delta;}}_E\}$

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

when the roundness error value is maximum:

when the roundness error value is not maximum:

wherein,_Athe straightness of the axis of the inner hole is shown,_B、_C、_D、_Ethe roundness of the inner hole of the cross section of each group of tapered pneumatic nozzles,_Findicating the bore taper.