JP2008096114A - Measuring apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measuring apparatus for high-efficiency and high-accuracy measurement perpendicularity. <P>SOLUTION: The measuring apparatus 10 is provided with a column 12 erected to a base 11; measuring devices 13; a moving base 17 which is elevated and lowered according to the rotation of a screw member 15; guides 22 mounted to a rail member 21; slide members 23, each having a tip to which a piece member 23a is attached and which move in the horizontal directions along each guide 22; measuring terminals 26 mounted to tips of four terminal holders 25; and a dome 27 for opening and closing the measuring terminals. The four measuring terminals 26 measure with high efficiency and high accuracy the perpendicularity, taper angles, etc. of the inner surfaces and the outer surfaces of work pieces W. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a measuring apparatus for measuring shape parameters such as perpendicularity and taper angle with respect to a reference surface, and more particularly to measures for improving work efficiency and measurement accuracy.

  In recent years, there has been a demand for higher precision and reduced manufacturing costs for various industrial equipment such as automobile parts. For this purpose, a means for measuring the accuracy of various industrial equipment parts with high efficiency is required. Further, not only the dimensions but also the shape parameters such as the squareness and the taper angle with respect to the reference plane are important for the accuracy of the parts.

  FIG. 7 shows a conventional measuring apparatus for measuring squareness disclosed in FIG. 9 of Patent Document 1. As shown in the figure, a conventional measuring apparatus 102 includes a table body 103 that moves horizontally on the surface plate 101, a column 104 that is orthogonal to the table body 103, a slider 105 that moves up and down along the column 104, And a measuring instrument 106 such as an indicator attached to the slider 105. In the measurement, the first surface W1 of the workpiece W is placed on the block gauge 107, the stopper 103A of the base body 103 is abutted against the block gauge 107, and the distance between the column 104 and the workpiece W is kept constant. The measurement terminal 106A of the measuring device 106 is brought into contact with the second surface W2 of the workpiece W, and the measuring device 106 is moved up and down along the support column 104 to measure the squareness.

JP-A-9-243351

  However, when the conventional measuring apparatus is used, the measuring device 106 is moved along the support column 104. Therefore, the squareness accuracy depends on the moving accuracy of the measuring device 106, and high-precision measurement cannot be expected. Further, it is difficult to use the measuring device 102 for measuring the perpendicularity between the inner surface and the end surface of the cylindrical part and measuring the taper of the inner and outer surfaces. In addition, there was a problem of poor work efficiency.

  Therefore, in Patent Document 1, the coordinates of each pair of points on two mutually orthogonal surfaces of the object to be measured are measured, and the perpendicularity between the straight lines connecting each pair of points is measured. However, such an apparatus cannot measure the perpendicularity between the inner surface and the end surface of the cylindrical product, and lacks applicability to various products.

  An object of the present invention is to provide a measuring apparatus capable of measuring shape parameters such as perpendicularity and taper angle of various products with high accuracy and high efficiency.

  The measurement apparatus of the present invention includes a plurality of measurement terminals that come into contact with the surface to be measured, and measures the shape parameter of the object to be measured by moving each measurement terminal in the vertical direction by a vertical movement member.

  As a result, data of a plurality of measurement positions can be obtained while moving a plurality of measurement terminals simultaneously in the vertical direction for various products, so that the measurement efficiency can be improved, and a plurality of data can be Since the inclination of the moving direction from the vertical direction can be calibrated, high-accuracy measurement is possible.

  By providing three or more measurement terminals, it is possible to measure the object to be measured with high accuracy while quickly correcting the inclination of the vertical movement.

  Since three or more measurement terminals are arranged on substantially the same circumference, measurement and data processing for correction are facilitated.

  By further including an arithmetic device that processes and computes data of a plurality of measurement terminals, it is possible to quickly perform correction calculations and pass / fail judgments.

  According to the measuring apparatus of the present invention, shape parameters such as squareness and taper angle can be measured with high efficiency and high accuracy.

(Embodiment)
FIG. 1 is a side view showing a main part of a measuring apparatus 10 according to an embodiment of the present invention. FIG. 1 shows a partially broken portion and a cross-sectional view for easy viewing. FIG. 2 is a perspective view schematically showing the entire measurement system including the measurement apparatus 10.

  The measuring apparatus 10 is attached to the base 11 provided in the horizontal direction, the support column 12 erected on the base 11, the measurement apparatus 13 for holding the workpiece W attached to the base 11, and the support column 12. The screw member 15, the moving base 17 that moves up and down along the guide surface of the support column 12 according to the rotation of the screw member 15, and the motor 18 that rotationally drives the screw member 15 are provided. That is, at the time of measurement, while the work W is attached to the measuring device 13, the moving table 17 is lowered to bring the measuring unit attached to the moving table 17 closer to the work W, while at the end of the measurement, It is comprised so that the attached measurement part may be raised.

  The measuring unit is provided with two rail members 21 orthogonal to each other, a total of four guides 22 attached to each rail member 21, and a piece member 23 a at the tip. In addition, four slide members 23 that move in the horizontal direction, a terminal holder 25 attached to each slide member 23, and a measurement terminal 26 attached to the tip of each terminal holder 25 are provided. On the other hand, a portion extending directly above the workpiece W in the movable table 17 is provided with a dome 27 for opening and closing the measurement terminal and an inner cylinder 28 for raising and lowering the dome 28. Although not shown, the slide member 23 is urged so as to be in close contact with the inner surface of the dome 27 and the inner surface of the work W by a spring provided between the slide member 23 and the rail member 21.

In the measurement unit, when the dome 27 is lowered by the cylinder 28, the four piece members 23a attached to the tip of the slide member 23 move in the direction of relative contraction. Will move. In this state, when the moving base 23 is lowered and the measurement terminal 26 is positioned near the lower end of the work W, and then the dome 27 is raised by the cylinder 28, each measurement terminal 26 comes into contact with the inner surface of the work W. It becomes a state.
Next, when the movable table 17 is raised, the measurement terminal 26 moves in the vertical direction while being in contact with the inner surface of the workpiece W, so that the squareness or taper angle of the inner surface of the workpiece W with respect to the reference surface (lower end surface) is increased. Measured.

  Here, of the four guides 22, each two guides 22 are on the same straight line, and each of the two guides 22 is orthogonal to each other. That is, the four guides 22 are arranged equally at 90 ° intervals on the substantially same circumference with respect to the center position, and the squareness and taper angle of the inner surface of the workpiece W are determined by the four measurement terminals 26. Are measured at 90 ° intervals. “Substantially on the same circumference” means that it is sufficient to be on the same circumference within an allowable error.

  The base of the measurement terminal 26 is urged by a spring member (not shown) built in the terminal holder 25, and the measurement pressure is applied to the measurement terminal 26 by this urging force and the measurement terminal 26 is moved. Wide width is secured. The dome 27 can be replaced according to the shape and size of the workpiece W.

  As shown in FIG. 2, clean air having a constant temperature (for example, 25 ° C. ± 0.2 ° C.) is supplied from the air conditioner 33 to the bench 35 on which the entire measuring apparatus 10 is installed. Have been supplied. The computer 31 controls the operation of the movable table 17 and the dome 27 and organizes information on the shape parameters such as the perpendicularity and taper of the workpiece W from the displacement of the measurement terminal 26.

  FIG. 3 is a block circuit diagram of a control system attached to the measuring apparatus 10. In the computer 31 incorporating the arithmetic unit, an A / D board for A / D converting the displacement signal of the measurement terminal 26, a motor control board for controlling the vertical position of the motor 18, and a stroke position of the cylinder 28 are provided. A PIO board for control is arranged, and various information is displayed on the monitor. The computer 31, the amplifier 32, the driver of the motor 18, and the cylinder 28 are electrically connected by signal wiring that passes through the base 11.

  The displacement of the measurement terminal 26 is converted into an electric signal by a displacement sensor built in the terminal holder 25, amplified by an amplifier 32, and sent to a computer 31 (A / D board). Then, the quality of the finished product can be determined from the data displayed on the monitor, or the quality can be automatically determined to be displayed on the monitor.

  Next, an example of detecting a deviation from the ideal shape of the movable table 17 and the reference block of the measuring apparatus 10 will be described. As in the present embodiment, by having four (at least three) measurement terminals 26, it is possible to easily obtain the deviation of the moving base 17 from the ideal perpendicular and the deviation of the reference block from the ideal shape. Can do. Note that the squareness, the taper angle, and the like are often expressed as displacement (μm) from the lower end position of the measurement terminal with respect to a certain measurement distance (for example, 21 mm) in actual data processing.

  FIG. 4 is a cross-sectional view of a tapered reference block for correcting a shift of the moving table from an ideal straight line. As shown in the inset, the tapered reference block BL has an inner surface (inclination angle α from the horizontal plane) having an upward enlargement. Then, the terminal holder 25 and the measurement terminal 26 are moved from the lower end to the upper end, and the horizontal displacement amount h from the reference position of the measurement terminal 26 according to the longitudinal movement amount v is measured.

  FIG. 5 is a diagram showing measurement data obtained at this time. As shown in the figure, when the moving table 17 moves ideally linearly, measurement data that coincides with the ideal straight line Li of the inclination angle α should be obtained. However, actually, measurement data as indicated by the measurement line Ld is obtained due to the error of each part of the measurement device 13. Therefore, the amount of deviation of the measurement line Ld from the ideal straight line Li is stored in the memory in the computer 31 as the correction value Cp. At this time, although there is an error in the inclination angle α, at this point, the straight line Li calculated from the measurement data by the least square method is obtained, and only the deviation amount from the straight line Li is calculated as the correction value Cp. When measuring the workpiece W, the measurement data is corrected by the correction value Cp corresponding to the vertical movement amount v of the measuring table 17. In addition, instead of the tapered reference block BL, a reference block having an inner surface of a right cylinder may be used, but by using the tapered reference block BL and arranging a plurality of measurement terminals 26 on the same circumference, When the error is the same, the horizontal movement amount h is enlarged, so that more accurate measurement can be realized.

  FIGS. 6A to 6D are diagrams illustrating examples of perpendicularity data obtained as a result of performing measurement by exchanging the measurement positions by the measurement terminals. In this example, it is assumed that four measurement positions x, y, z, and w of the same cylindrical reference block as the workpiece W are measured by measurement terminals a, b, c, and d. Then, as shown in FIGS. 6A to 6D, the reference block is rotated clockwise by 90 °, and each of the four square measured values Rxa to Rwd, Rxb to Rwa, Rxc to Rwb. , Rxd to Rwc are obtained. The measurement data is obtained as the horizontal displacement amount h of the measurement terminal 26 with respect to the vertical movement amount v.

  At this time, since the bottom surface of the measuring device 13 on the base 11 and the guide surface of the support column 12 that guides the vertical movement of the moving table 17 are not strictly perpendicular to each other, the moving direction of the moving table 17 is measured. It has a certain inclination with respect to the direction perpendicular to the bottom surface of the device 13. Due to this inclination, certain measurement errors Ea to Ed appear at the respective measurement terminals a to d.

Therefore, the squareness error at each measurement position x, y, z, w is defined as Ex, Ey, Ez, Ew. Even when the reference block is rotated and set at the four positions shown in FIGS. 6A to 6D, this error is the same value Ex, Ey, Ez, Ew at the measurement positions x, y, z, w. It has become.

  On the other hand, since the true squareness (data to be obtained) at each measurement position x, y, z, w must be unchanged even if the measurement terminals are switched, the trueness at each measurement position x, y, z, w must be unchanged. Assuming that the squareness of Tx, Ty, Tz, and Tw is as follows, the following relationships are obtained from the measurements shown in FIGS.

The following formulas (1) to (4) are obtained by the measurement shown in FIG.
Tx = Rxa-Ex-Ea (1)
Ty = Ryb-Ey-Eb (2)
Tz = Rzc-Ez-Ec (3)
Tw = Rwd−Ew−Ed (4)
Is obtained. However, since Ex˜ is an initial value before the reference block is rotated, it can be set to 0.

By the measurement shown in FIG. 6B, the following formulas (5) to (8)
Tx = Rxb-Ex-Eb (5)
Ty = Ryc-Ey-Ec (6)
Tz = Rzd-Ez-Ed (7)
Tw = Rwa-Ew-Ea (8)
Is obtained.

By the measurement shown in FIG. 6C, the following formulas (9) to (12)
Tx = Rxc-Ex-Ec (9)
Ty = Ryd−Ey−Ed (10)
Tz = Rza-Ez-Ea (11)
Tw = Rwb-Ew-Eb (12)
Is obtained.

By the measurement shown in FIG. 6D, the following formulas (13) to (16)
Tx = Rxd−Ex−Ed (13)
Ty = Rya-Ey-Ea (14)
Tz = Rzb-Ez-Eb (15)
Tw = Rwc-Ew-Ec (16)
Is obtained.

  Rxa to Rwd, Rxb to Rwa, Rxc to Rwb, Rxd to Rwc are actually measured values, and there are twelve unknowns Tx to Tw, Ex-Ew, and Ea to Ed. By carrying out the measurement in step S1, the true squareness at each measurement position and the inclination of the moving table 17 in the vertical movement direction can be obtained from the above 16 relational expressions. At this time, even if the reference block is not measured at the four positions shown in FIGS. 6A to 6D, in principle, the inclination of the moving base 17 in the vertical movement direction should be obtained at only three positions. However, depending on how the moving direction is tilted, it may not be obtained accurately. Therefore, it is desirable to perform measurement at four locations to minimize the error.

In this example, the example in which the squareness is measured using a right cylindrical block has been described. However, when measuring the tapered surface of a tapered workpiece, the taper reference block is used to calculate the formula (1) to The taper error based on (16) and the inclination of the movable table 17 can be obtained. And for a product measurement and pass / fail judgment, a true squareness and a taper can be calculated | required using the measurement result in one place.

  According to the present embodiment, the four measurement terminals 26 can detect the perpendicularity, taper, and the like with respect to the inner and outer end surfaces of the workpiece W quickly and with high accuracy by a single measurement. When trying to obtain the same data as in the present invention using a single measurement terminal as in the prior art, there is no choice but to measure four measurement positions with one measurement terminal. In addition to improving work efficiency, the following effects can be achieved.

  For example, even if the measurement is performed at the four measurement positions shown in FIGS. 6A to 6D by using a single measurement terminal and rotating the reference block, the equations (1), (8), (11) , (14) only. Therefore, even if it is assumed that there is no error in the reference block, the five unknowns Tx, Ty, Tz, Tw, and Ea cannot be obtained from the four relational expressions. Therefore, it is necessary to obtain the inclination of the moving direction of the movable table 17 with respect to the bottom surface of the measuring apparatus 13 by another troublesome measurement, or to manufacture a measuring apparatus with high accuracy to such an extent that this inclination can be ignored. However, even if the accuracy is initially high, the accuracy deteriorates due to the secular change of the measuring apparatus 10 and the wear of the sliding portion. From the above, it is not always possible to expect high-precision measurement even when using an assumed device having only a single measurement terminal as in the prior art.

  On the other hand, in the measurement apparatus of the present invention, first, using a reference block, from the measurement data obtained by the plurality of measurement terminals 26 at a plurality of positions, the inclination from the vertical relationship between the moving direction of the movable table 17 and the measurement apparatus 13, and the reference Processing to remove block errors can be performed. That is, assuming that the corrected measurement data is Rxa ′, Ryb ′, Rzc ′, Rwd ′, Tx = Rxa ′, Ty = Ryb ′, Tz = Rzc ′, Tw = Rwd from the equations (1) to (4). Therefore, the squareness and the taper angle can be detected quickly and with high accuracy from the measurement data at one measurement position (for example, the position shown in FIG. 6A).

  Moreover, since errors such as the squareness of the reference block can be detected, it is not necessary to prepare an extremely accurate and expensive reference block. Therefore, even if the cost of the measuring device is high, the total inspection cost can be reduced including the running cost. Furthermore, even if the verticality of the movable table 17 deteriorates due to aging, the measurement accuracy can be kept high by measuring the correction amount using the reference block each time.

  In addition, the measurement apparatus 10 of the present embodiment can measure not only the squareness but also other shape parameters such as taper and cylindricity. Even when the taper angle is measured, it is easy to expand the stroke of the slide member 23 by devising the shape of the inner surface of the dome 27, so that no special additional equipment is required.

  In addition, since the measurement terminal 26 of the present embodiment can be made extremely fine, it is possible to measure the squareness of the inner surface of the product, which is difficult with a laser measuring instrument. Specifically, for a cylindrical product having an inner surface with an inner diameter of 90 mm or less, high-accuracy measurement with a displacement error within ± 1 μm is performed in a measurement time of about 10 seconds for a measurement range (depth) of 21 mm. I was able to.

  In the present embodiment, four measurement terminals are provided. However, by providing at least three measurement terminals, the movable table 17 with respect to the bottom surface of the measurement device 13 using the reference block is provided as in the present embodiment. It is possible to easily calculate a correction amount in consideration of the inclination in the vertical movement direction and the error of the reference block.

  On the other hand, when there are two measurement terminals, for example, like the two measurement terminals a and b in the present embodiment, if the moving direction of the slide member 23 is not in a straight line but crosses each other, From the data at the four measurement positions in FIGS. 6A to 6D, the above formulas (1), (2), (5), (8), (11), (12), (14), (14), ( The eight formulas of 15) can be used. Therefore, it is possible to obtain the inclination of the moving table 17 in the vertical movement direction with respect to the bottom surface of the measuring device 13 under the assumption that there is no error in the reference block. However, when the movement direction of the slide member 23 is parallel as in the case of the measurement terminals a and c (when the vector on the plane is linearly dependent), information on the inclination in the vertical movement direction orthogonal to this is obtained. Therefore, there may be a case where the inclination in the vertical movement direction cannot be corrected.

(Other embodiments)
The structure of the embodiment of the present invention disclosed above is merely an example, and the scope of the present invention is not limited to the scope of these descriptions. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

  In the above embodiment, the workpiece W is cylindrical, but the shape of the workpiece may be irregular regardless of the inner surface or the outer surface.

  The measuring apparatus of the present invention can be used for measuring various shape parameters such as perpendicularity, straightness, cylindricity, parallelism, taper angle, and surface waviness of various machine parts.

It is a side view which shows the principal part of the measuring apparatus in embodiment of this invention. It is a perspective view showing roughly the whole measuring system including a measuring device. It is a block circuit diagram of the control system attached to the measuring apparatus. It is sectional drawing of the reference block with a taper for correct | amending the deviation | shift from the ideal straight line of a moving stand. It is a figure which shows the measurement data for correct | amending the deviation | shift from the ideal straight line of a moving stand. (A)-(d) is a figure which shows the example of the squareness data obtained as a result of measuring by replacing the measurement position by a measurement terminal. This is a conventional measuring apparatus disclosed in FIG. 9 of Patent Document 1 for measuring a perpendicularity.

Explanation of symbols

W Workpieces a, b, c, d Measuring terminals x, y, z, w Measuring position 10 Measuring device 11 Base 12 Column 13 Measuring device 15 Screw member 17 Moving table 18 Motor 21 Rail member 22 Guide 23 Slide member 23a Frame member 25 Terminal holder 26 Measuring terminal 27 Dome 28 Cylinder 31 Computer 32 Amplifier 33 Air conditioner 34 Air conditioning duct 35 Bench 24 Fixing member

Claims (4)

A plurality of measurement terminals for contacting the measurement surface of the measurement object;
A base member having a holding portion for installing the object to be measured;
A column attached to the base member;
A longitudinally moving member that moves longitudinally along the column;
The same number of lateral movement members attached to the longitudinal movement member for moving the plurality of measurement terminals laterally; and
Measuring device. The measuring apparatus according to claim 1,
The measurement apparatus, wherein the plurality of measurement terminals are provided in three or more. The measuring device according to claim 2, wherein
The three or more measurement terminals are arranged on substantially the same circumference as viewed in plan. In the measuring apparatus in any one of Claims 1-3,
A measurement apparatus, further comprising an arithmetic device that processes and calculates data of the plurality of measurement terminals.

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