JP2012068202A - Straightness measuring device and straightness measuring method - Google Patents

Abstract

An object of the present invention is to propose a straightness measuring apparatus capable of measuring straightness with high accuracy and a straightness measuring method using the straightness measuring apparatus.
A measurement surface Ms of an object to be measured 1 and an auxiliary reference surface Re of an auxiliary reference portion 2 are provided in an opposed state and relatively movable, and a measurement head portion 3 of an air micrometer is formed in a scanning section S formed by these. Is moved in the scanning direction, and a scanning measurement value composed of a sum of a distance from the first sensor unit 4 to the measurement target surface Ms and a distance from the second sensor unit 5 to the auxiliary reference surface Re at each measurement point is obtained. A straightness measuring device configured to measure and calculate, and to measure and calculate the straightness of the measured surface Ms from the difference between the scanning measurement values before and after the auxiliary reference portion 2 moves relative to the DUT 1. .
[Selection] Figure 4

Description

  The present invention relates to a straightness measuring device using an air micrometer and a straightness measuring method using the straightness measuring device.

  Along with the increasing demands for improving the machining accuracy of large workpieces, there is also a need for improvements in the measurement accuracy of the machine tool straightness and the straightness of the machined surface.

  In general, a straight ruler is used as a standard for measuring the straightness of a machine, and a high-precision straightness of the machine is used for measuring the shape of a workpiece. In some cases, the inversion method or the multipoint method may be used.

  Also, it is common to use a level for rolling straightness measurement and an autocollimator for pitching and yawing measurement.

  The above-described level and autocollimator are also used for high-precision measurement of the straight shape error of a long workpiece in a horizontal plane.

  However, the spirit level has the disadvantages that the response speed is low and cannot be used for yawing measurement, and when the autocollimator is used on a machine tool, the response speed must be reduced to reduce noise. There are some disadvantages.

  Furthermore, in the sequential two-point method using a level or an autocollimator, it is not easy to change the interval between two points, and there is a problem that it is difficult to interpolate that requires a particularly narrow contact interval.

  In addition, with the inversion method, the measurement surface in the horizontal plane cannot be measured correctly due to the influence of the deflection due to gravity. In the multipoint method, various solutions for the zero point problem in the three-point method, which is a representative example of this multipoint method, have been proposed recently, but there are still problems such as the problem of drift during measurement. This is a big problem for a long object to be measured with a long measurement time, and has not been put to practical use.

  Therefore, the present invention improves the various problems in the straightness measurement as described above, and can measure the straightness with high accuracy, and the straightness measurement using the straightness measurement device. The purpose is to propose a method.

  The gist of the present invention will be described with reference to the accompanying drawings.

  A straightness measuring apparatus using an air micrometer, in which a surface to be measured Ms of an object to be measured 1 and an auxiliary reference surface Re of an auxiliary reference portion 2 are provided in an opposing state, and the surface to be measured Ms provided in this opposing state. A predetermined range between the auxiliary reference surface Re and the auxiliary reference surface Re is defined as a scanning section S, and the measuring head unit 3 of the air micrometer is movably provided in the scanning section S. The measuring head unit 3 is connected to the measured surface Ms. The measurement in which the first sensor unit 4 is provided at an opposing position and the second sensor unit 5 is provided at a position opposing the auxiliary reference plane Re, and the first sensor unit 4 and the second sensor unit 5 are provided. The head unit 3 is scanned and moved in a predetermined direction, and the distance from the first sensor unit 4 to the surface to be measured Ms at a large number of measurement points in the scanning section S and the auxiliary reference surface Re from the second sensor unit 5 are measured. Running consisting of the sum of the distance to The measurement value is measured and calculated, the measured object 1 and the auxiliary reference part 2 are provided to be relatively movable, and the auxiliary reference part 2 with respect to the measured object 1 or the auxiliary reference part 2 Alternatively, the straightness of the surface to be measured Ms is measured and calculated from the difference value between the scanning measurement values in the scanning section S before the relative movement of the object to be measured 1 and the scanning section S after the relative movement by a predetermined distance. The present invention relates to a straightness measuring apparatus that is configured as described above.

  In addition, an inclination measuring unit 6 is provided in the object to be measured 1 or the auxiliary reference part 2, and the inclination of the object to be measured 1 or the auxiliary reference part 2 before and after relative movement with respect to the auxiliary reference part 2 or the object to be measured 1. The straightness measuring apparatus according to claim 1, wherein the degree of straightness is measured and corrected based on the measured inclination to measure and calculate the straightness of the measured surface Ms. is there.

  Further, a scanning guide part 7 for linearly moving the measurement head part 3 is provided between the surface to be measured Ms and the auxiliary reference surface Re. This relates to the straightness measuring apparatus described in the item.

The length of the measurement head unit 3 in the scanning direction is X, the length in the width direction orthogonal to the scanning direction is Y, and the thickness is T. The clearance between the measurement head unit 3 and the surface to be measured Ms is C ₁ , the clearance between the measurement head unit 3 and the auxiliary reference surface Re is C ₂ , the maximum pitching angle when the measurement head unit 3 is tilted to the maximum in the front-rear direction with respect to the scanning direction is θx, and the measurement (T + C ₁ + C ₂ ) × (1 / COS θx−1) <required measurement accuracy or resolution, and (T + C ₁ ), where θy is the maximum rolling angle when the head unit 3 is tilted to the left and right with respect to the scanning direction. The X, Y, T, C ₁ , and C ₂ are set so that + C ₂ ) × (1 / COSθy−1) <required measurement accuracy or resolution. Related to the straightness measuring device described in item 1 It is.

  Further, the auxiliary reference portion 2 has a structure in which a base portion 2a having a lower surface as the auxiliary reference surface Re is installed on an opposing base support portion 2b, and the base support portion 2b is placed on the measured surface Ms or the measured surface. The straightness measuring apparatus according to any one of claims 1 to 4, wherein the measuring object 1 is movably mounted on a mounting table on which the measuring object 1 is mounted.

  Further, a fixing tool 12 is provided in the measurement head unit 3, the scanning movement of the measurement head unit 3 is prevented, and the measurement head unit 3 is fixed at a predetermined position in the scanning section S, and the auxiliary reference unit 2 is provided with a connection adapter portion 13, which is detachably provided on a spindle tool holder 14 of a machine tool, and the connection adapter portion 13 is connected to the spindle tool holder 14 of the machine tool. The auxiliary reference portion 2 is provided on the spindle tool holder 14 and is provided in a state of being opposed to the surface of the machining table 15 of the machine tool. The machining table 15 is moved to move the first of the measurement head portion 3 in the fixed state. Scanning measurement values comprising the sum of the distance from the sensor unit 4 to the surface of the machining table 15 and the distance from the second sensor unit 5 to the auxiliary reference plane Re are measured and calculated. In which according to the straightness measuring device according to any one of claims 1 to 5, characterized by being configured so as to measure the movement straightness of the machining table 15 in Rukoto.

  Moreover, it is a straightness measurement method using the straightness measuring apparatus of any one of Claims 1-5, Comprising: The to-be-measured surface Ms of the said to-be-measured object 1 and the auxiliary | assistant reference plane of the said auxiliary | assistant reference part 2 Re is provided in a facing state, and a predetermined range between the measured surface Ms and the auxiliary reference surface Re provided in the facing state is defined as the scanning section S, and the measuring head of the air micrometer is included in the scanning section S. The measurement head unit 3 includes the first sensor unit 4 at a position facing the surface to be measured Ms and the second sensor unit 5 at a position facing the auxiliary reference surface Re. The measurement head unit 3 is scanned and moved in a predetermined direction, and the distance from the first sensor unit 4 to the measured surface Ms and the second sensor unit 5 at a large number of measurement points in the scanning section S. Total with the distance to the auxiliary reference plane Re The scan measurement value is measured and calculated, and the object to be measured 1 and the auxiliary reference part 2 are provided to be relatively movable, and the auxiliary reference part 2 or the auxiliary reference part 2 with respect to the object to be measured 1 or the auxiliary reference part 2 The straightness measurement method is characterized in that the straightness of the measured surface Ms is measured and calculated from the difference value of the scanning measurement values in the respective scanning sections S before and after the relative movement of the DUT 1. .

The straightness measuring method using the straightness measuring apparatus according to any one of claims 1 to 5, wherein the auxiliary reference portion 2 is moved relative to the device under test 1. the position of the auxiliary reference unit 2 and the first scan position, the auxiliary reference portion a predetermined range between said measurement surface Ms and second auxiliary reference plane Re as the first scanning section S ₁ which is disposed in a first scan position the first scanning section the measuring head 3 of the air micrometer in the scanning direction of the S ₁ scan movement, the surface to be measured from the first sensor unit 4 in a number of measurement points of the first scanning section S ₁ A distance to Ms and a distance from the second sensor unit 5 to the auxiliary reference plane Re are respectively measured, and a distance from the first sensor unit 4 to the auxiliary reference plane Re at each measurement point and the first Distance from the two sensor unit 5 to the auxiliary reference plane Re And the auxiliary reference portion 2 is moved relative to the device under test 1 by a predetermined distance in the scanning direction, and the auxiliary reference portion 2 with respect to the device under test 1 is obtained. The position of the auxiliary reference portion 2 after the relative movement is set as the second scanning position, and a predetermined range between the auxiliary reference surface Re of the auxiliary reference portion 1 arranged at the second scanning position and the measured surface Ms. was the second scanning section S _2, the second scanning section the measuring head 3 of the air micrometer in the scanning direction of the S ₂ scan movement, the second scanning section the first in a number of measurement points S ₂ A distance from the sensor unit 4 to the measurement target surface Ms and a distance from the second sensor unit 5 to the auxiliary reference plane Re are measured, and the measurement target is measured from the first sensor unit 4 at each measurement location. The distance to the surface Ms and the second sensor unit 5 Is obtained as the second scanning measurement value, and the straightness of the measured surface Ms is calculated from the difference value between the first scanning measurement value and the second scanning measurement value. The present invention relates to a straightness measurement method characterized by:

  Further, the degree of inclination before and after the auxiliary reference part 2 moves relative to the part to be measured 1 is measured, a relative inclination is obtained based on the measured degree of inclination, and the first inclination is determined using the relative inclination. 9. The straightness measurement method according to claim 8, wherein a straightness of the measurement target surface Ms is calculated by correcting a difference value between the scan measurement value and the second scan measurement value.

  A straightness measurement method using the straightness measurement apparatus according to claim 6, wherein a fixture 12 is provided in the measurement head unit 3 to place the measurement head unit 3 at a predetermined position in the scanning section S. In a fixed state, the auxiliary reference part 2 is provided with a connection adapter part 13, the connection adapter part 13 is connected to a spindle tool holder 14 of a machine tool, and the auxiliary reference part 2 is provided on the spindle tool holder 14, A distance from the first sensor unit 4 of the measurement head unit 3 in the fixed state to the surface of the machining table 15 is provided by moving the machining table 15 so as to face the surface of the machining table 15 of the machine tool. A scanning measurement value composed of a sum of a distance from the second sensor unit 5 to the auxiliary reference plane Re is measured and calculated to measure and calculate the movement straightness of the machining table 15. Those relating to straightness measuring method.

  Since the present invention is configured as described above, in each scanning section before and after the auxiliary reference plane has moved a predetermined distance with respect to the measurement surface (or before and after the measurement surface has moved a predetermined distance with respect to the auxiliary reference surface). The straightness can be obtained by an extremely easy operation that merely obtains the difference value of the scanning measurement value, and more stable difference values can be obtained at a large number of measurement points as compared with the conventional sequential two-point method. This is an epoch-making straightness measuring apparatus excellent in practicality that can measure straightness with high accuracy.

  Furthermore, since the present invention employs an air micrometer as the measuring means, the measurement factor is air, so it is not easily affected by oil or dust adhering to the surface to be measured, and the properties of the surface to be measured (for example, A revolutionary straightness measuring device with excellent practicality that can be measured without damaging the surface to be measured. Become.

  In addition, since the scanning speed of this air micrometer's measuring head is not affected by the response speed of the level or autocollimator, the time required for long measurements can be greatly reduced, and the sensor layout space can be made more compact. For example, in the displacement sensor of another principle, since two independent displacement sensors are used, the apparatus becomes large due to the arrangement space of the sensors, and the arithmetic device before being taken into the computer to calculate the sum of both sensor outputs However, in the present invention, the interface between the sensor and the computer is simplified in the present invention. It becomes an extremely simple configuration.

  Moreover, even if the measurement head part moves up and down, the total value of the flow rate of the compressed air discharged from the first sensor part and the second sensor part does not change, so there is no need to control the vertical movement of the measurement head part. Therefore, since the first sensor unit and the second sensor unit provided in the measurement head unit can be easily and accurately arranged on the axis to be measured, for example, it is difficult to be affected by pitching, yawing and rolling during measurement. Since the total value of the flow rate of the compressed air discharged from the first sensor unit and the second sensor unit can be detected with extremely high accuracy, it is an epoch-making that can measure the straightness of the measured surface with high accuracy. Straightness measuring device.

  Further, in the method of measuring the straightness by calculating the difference by moving the auxiliary reference part or the measured object relative to the measured object or the auxiliary reference part as in the present invention, the measured object or the auxiliary reference part The posture change before and after the movement becomes a parabolic error of the measured shape, but the measurement result is corrected based on the inclination measured by the inclination measuring unit, so that no parabolic error occurs and the straightness can be measured with high accuracy. it can.

  In addition, it is configured to read the inclination measured by the inclination measurement unit only twice before and after the movement of the object to be measured or the auxiliary reference part, so that it takes enough time to achieve the resolution to the limit of the performance of the inclination measurement unit. Therefore, it becomes an epoch-making straightness measuring device that can measure the straightness with high accuracy while further eliminating the parabolic error.

  According to the sixth aspect of the present invention, the straightness measuring apparatus is excellent in practicality and can easily measure the moving straightness of the machining table of the machine tool with an extremely simple configuration.

FIG. 3 is an explanatory cross-sectional view illustrating a measurement head unit of Example 1. 3 is an explanatory diagram of an air micrometer in Embodiment 1. FIG. 2 is an explanatory diagram illustrating a mathematical principle configuration of Example 1. FIG. 1 is an explanatory perspective view illustrating Example 1. FIG. 1 is an explanatory cross-sectional view illustrating Example 1. FIG. It is a figure explaining the idea at the time of determining each clearance between the measurement head part in Example 1, and a to-be-measured surface and an auxiliary reference plane. FIG. 3 is an explanatory perspective view illustrating a state in which the measurement head unit of Example 1 is configured to automatically scan. 1 is an explanatory perspective view illustrating a state in which a linear scale portion is provided in Example 1. FIG. It is explanatory drawing which shows the relative movement of the auxiliary | assistant reference | standard part of Example 1. FIG. FIG. 6 is an explanatory perspective view showing Example 2.

  An embodiment of the present invention which is considered to be suitable will be briefly described with reference to the drawings showing the operation of the present invention.

  Since the present invention uses an air micrometer as the measuring means, for example, the first sensor part 4 and the second sensor part 5 are formed in the shape of a nozzle from which compressed air is discharged, as shown in FIGS. In addition, the compressed air is discharged from the first sensor unit 4 and the second sensor unit 5, and the shape of each measurement surface Ms, Re is measured from each sensor unit 4, 5 by measuring the change in the flow rate of this compressed air. Therefore, it is an epoch-making straightness measuring apparatus excellent in practicality that can measure the straightness of the surface Ms to be measured with high accuracy based on the measurement result.

Specifically, the flow rate Q _{1 of} compressed air discharged from the first sensor unit 4 and the second sensor unit 5 (flow rate of compressed air discharged from the first sensor unit 4), Q ₂ (discharged from the second sensor unit 5) The flow rate of the compressed air) is the peripheral diameter πd (d is the diameter of the nozzle-like sensor portion) of the nozzle-like sensor portion, and the distance h ₁ from the tip of the first sensor portion 4 to the surface Ms to be measured (second) The relationship is linear with the area πdh ₁ (πdh ₂ ) of the cylindrical side surface formed by the distance h ₂ from the tip of the sensor unit 5 to the auxiliary reference plane Re.

Further, πd of the aforementioned cylindrical side surface area πdh ₁ (πdh ₂ ) is a fixed value. Therefore, the flow rates Q ₁ and Q ₂ of the compressed air discharged from the first sensor unit 4 and the second sensor unit 5 are It can be said that there is a linear relationship with the distances h ₁ and h ₂ to the surfaces where the first sensor portion 4 and the second sensor portion 5 face each other, that is, the measured surface Ms and the auxiliary reference surface Re. The discharge flow rate of Q ₁ = kπd ₁ h ₁ (k: constant, d ₁ : diameter of the first sensor unit 4 formed in a nozzle shape) and Q ₂ = kπd ₂ h ₂ (k: constant, d ₂ : nozzle) And the diameter of the second sensor portion 5 formed in a shape.

Here, for example, by adjusting the nozzle diameters of the first sensor unit 4 and the second sensor unit 5 so that d ₁ = d ₂ = d, the first sensor unit 4 and the second sensor unit 5 The total value Q ₁ + Q ₂ of the compressed air to be discharged can be expressed as Q ₁ + Q ₂ = kπd (h ₁ + h ₂ ).

That is, the distance h ₁ from the tip portion of the first sensor unit 4 to the surface to be measured Ms, sum h _{1 +} h ₂ and the distance h ₂ from the distal end portion of the second sensor unit 5 to the auxiliary reference plane Re is Q ₁ + Q ₂ can be obtained. Therefore, the calculation of the sum of h ₁ and h ₂ detected by the first sensor unit 4 and the second sensor unit 5 is performed in the measurement head unit 3, for example, Since it can be easily realized by providing one common piping portion 8 by drilling or the like, it becomes a straightness measuring device excellent in practicality that does not require any special calculation.

  The mathematical principle configuration of the present invention will be described with reference to FIG.

  In FIG. 3, the scanning direction is the x direction, and the straight unevenness in the height direction is taken in the z direction. It is assumed that the straight shape of the auxiliary reference surface Re of the auxiliary reference portion 2 is represented by f (x) and the straight shape of the measured surface Ms of the device under test 1 is represented by g (x).

  FIG. 3A shows a state in which the origins of the shapes of the auxiliary reference surface Re and the surface to be measured Ms are matched to face each other. At this time, when the shape is simultaneously scanned and measured by the first sensor unit 4 and the second sensor unit 5 provided in the measurement head unit 3, the scanning motion error Ez of the measurement head unit 3 is positive with respect to the first sensor unit 4. Acting on the second sensor unit 5 in the negative direction, or conversely acting on the first sensor unit 4 in the negative direction and against the second sensor unit 5 in the positive direction. Since it acts in the opposite direction, such as acting, the sum (total value) of the outputs of the first sensor unit 4 and the second sensor unit 5 can be expressed as in equation (1), resulting in a scanning motion error. Ez cancels out and is not included in equation (1). Note that a certain amount of offset not related to the shape is omitted.

The x-axis shown in FIG. 3, for example, begins with x = _{x 0, x 1,} x 2 arranged at intervals D, · · ·, the first sensor unit 4 and the second sensor portion 5 in terms of _{x N} Assume that the output is sampled.

  Next, as shown in FIG. 3B, for example, the auxiliary reference portion 2 is moved by a distance D in the x direction with respect to the device under test 1. In other words, when the auxiliary reference surface Re is moved by the distance D in the x direction with respect to the surface to be measured Ms and scanning measurement is performed again, the differential output is given as shown in Equation (2).

Here, Z _D is an auxiliary reference plane Re (auxiliary reference unit 2), for example, a z-direction offset generated when the distance moved by D. Note that not only the offset in the z direction but also the inclination in the x direction occurs during the movement. The influence of this inclination is caused by, for example, providing the measurement object 1 or the auxiliary reference unit 2 with the inclination measuring unit 6. Since the degree can be detected and corrected based on the detected inclination, it is omitted in equation (2).

  Here, when the difference between Expression (1) and Expression (2) is taken, Expression (3) is obtained, and the difference value of the measurement target surface Ms of the object to be measured 1 is obtained.

  From this difference value, it is understood that both the scanning motion error Ez in the scanning measurement and the shape error of the auxiliary reference surface Re are theoretically completely removed.

When g (x ₀ ) = 0 is given as an initial value to the above formula (3), g (x ₁ ), g (x ₂ ), g (x ₃ ),..., G (x _N ), g (x _{N + 1} ) is obtained sequentially.

However, since an inclination of xZ _D / D is added to the whole due to the influence of Z _D , it is necessary to remove this inclination, which is to align both ends with a straight shape expression, that is, in the above case, g (x _By setting ₀ ) = g (x _{N + 1} ), this inclination can be removed.

  A first embodiment of the present invention will be described with reference to FIGS.

  The present embodiment is a straightness measuring apparatus using an air micrometer, in which the surface to be measured Ms of the object to be measured 1 and the auxiliary reference surface Re of the auxiliary reference portion 2 are provided in an opposing state, and provided in this opposing state. A predetermined range between the measured surface Ms and the auxiliary reference surface Re is defined as a scanning section S, and the measuring head unit 3 of the air micrometer is provided movably in the scanning section S. The first sensor unit 4 is provided at a position facing the surface Ms, the second sensor unit 5 is provided at a position facing the auxiliary reference surface Re, and the measuring head unit 3 is scanned and moved in a predetermined direction. It is configured to measure and calculate a scanning measurement value composed of a sum of a distance from the first sensor unit 4 to the measurement target surface Ms and a distance from the second sensor unit 5 to the auxiliary reference surface Re in a large number of measurement locations, Relative movement of DUT 1 and auxiliary reference part 2 The straightness of the surface to be measured Ms is determined from the difference value of the scanning measurement values in the respective scanning sections S before and after the relative movement of the auxiliary reference part 2 or the measurement object 1 with respect to the measurement object 1 or the auxiliary reference part 2. A straightness measuring device configured to measure and calculate.

  Specifically, the auxiliary reference portion 2 has a structure in which a base portion 2a having a lower surface as the auxiliary reference surface Re is installed on an opposite base support portion 2b, and the base support portion 2b is placed on the surface to be measured Ms or the surface to be measured. In this embodiment, a configuration in which the object 1 is movably mounted on the mounting table on which the measurement object 1 is mounted is shown.

  More specifically, as shown in FIG. 4, the base portion 2a is formed of a rectangular block body, and base support portions 2b are provided in opposing states at both longitudinal ends of the block body. The base portion 2a is provided in a erected state on the support portion 2b.

  In addition, the base body support portion 2b has a structure in which a leg portion 2c is detachably provided at the bottom.

  Further, a scanning guide portion 7 is provided between the opposing substrate support portions 2b so as to guide the slide movement during the scanning movement of the measurement head portion 3 described later.

The scanning guide unit 7 prevents the measurement head unit 3 from falling off the apparatus when the apparatus is lifted when the measurement head unit 3 is moved and measured while being in contact with the surface to be measured Ms. This has the effect of preventing displacement in the Y direction during scanning movement, that is, in the direction orthogonal to the scanning direction, in other words, in the left-right direction. In addition, the measurement head unit 3 is scanned in a non-contact state with the measurement surface Ms. In the case of moving and measuring, in addition to the above effects, appropriate clearances C ₁ between the measurement head unit 3 and the measurement target surface Ms and the auxiliary reference surface Re provided in the vertical direction of the measurement head unit 3 are provided. , C ₂ .

  Furthermore, the auxiliary reference unit 2 is provided with an inclination measuring unit 6 to measure the inclination of the auxiliary reference unit 2 before and after relative movement with respect to the object to be measured 1 and to perform correction based on the measured inclination. The straightness of the measurement surface Ms is measured and calculated.

  Specifically, in the present embodiment, a level is adopted for the inclination measuring unit 6, and this is attached to the upper surface of the base portion 2 a of the auxiliary reference unit 2, that is, the back surface of the auxiliary reference surface Re. .

  In addition to the above-described level, an autocollimator may be employed as the inclination measuring unit 6. When this autocollimator is employed, the position where the above-described level is provided, that is, on the back surface of the auxiliary reference plane Re. A reflecting mirror of the autocollimator is provided, and the autocollimator body is configured to be provided on an arbitrary empty space on the surface to be measured Ms or another stable structure.

  Further, in this embodiment, an air micrometer is used for the sensor parts 4 and 5, and the measurement head part 3 of the air micrometer branches the tip of the common pipe part as shown in FIG. One is the first sensor unit 4 and the other is the second sensor unit 5, and the first sensor unit 4 and the second sensor unit 5 are provided on the same line in the vertical direction. Is configured to flow out.

  Specifically, the first sensor unit 4 is provided on the lower side of the measurement head unit 3, that is, on the measured surface Ms side, with the tip portion directed toward the measured surface Ms side. The second sensor unit 5 is provided on the auxiliary reference plane Re side with the tip portion facing the auxiliary reference plane Re, and the measurement directions of the first sensor unit 4 and the second sensor unit 5 are aligned. By arranging and arranging based on the so-called Abbe's principle, the shape comparison (measurement of the sum of both) of the measured surface Ms and the auxiliary reference surface Re can be realized with high accuracy. The straightness can be measured with high accuracy.

  Further, the air micrometer used in the present embodiment adopts a differential pressure type air micrometer, and this differential pressure type air micrometer can easily convert the output into an electric signal, and supplied compressed air. It is excellent in that accuracy is hardly affected by the performance of the regulator for keeping the pressure constant, and that the clearance between the nozzle and the measurement surface can be made larger than that of a flow-type air micrometer.

Further, as shown in FIG. 6, the measurement head unit 3 has the measurement head unit 3 in the scanning direction length X, the width direction length perpendicular to the scanning direction and the horizontal direction Y, and the thickness T. When the clearance between the head portion 3 and the measurement target surface Ms is C ₁ , the clearance between the measurement head portion 3 and the auxiliary reference surface Re is C ₂ , and the measurement head portion 3 is tilted to the maximum with respect to the scanning direction. (T + C ₁ + C ₂ ) × (1 / COSθx−1) <necessary measurement, where θx is the maximum pitching angle and θy is the maximum rolling angle when the measuring head unit 3 is tilted to the left and right with respect to the scanning direction. In this embodiment, X, Y, T, C ₁ and C ₂ are set such that the accuracy or resolution and (T + C ₁ + C ₂ ) × (1 / COSθy−1) <required measurement accuracy or resolution are satisfied. The number of required measurement accuracy or resolution The value is set to 0.05 μm.

  Further, a handle portion 9 is provided on the side surface of the measurement head unit 3, and when the measurement head unit 3 is scanned and moved, the handle unit 9 is picked and the measurement head unit 3 is moved in the scanning direction. Yes. In the scanning movement of the measuring head unit 3, as shown in FIG. 7, a driving unit 10 is provided in the auxiliary reference unit 2, and the driving unit 10 is connected to a scanning guide unit 7 configured in a feed screw shape. Then, a female screw part to be screwed with the scanning guide part 7 is formed in the measurement head part 3, and the scanning guide part 7 is driven by the driving part 10 in a state where the measurement head part 3 and the scanning guide part 7 are screwed. The measurement head unit 3 may be automatically moved in the scanning direction by rotating the scanning guide unit 7 and rotating the scanning guide unit 7.

  Moreover, as shown in FIG. 8, it is good also as a structure which can provide the linear scale part 11 in the side surface of the base | substrate part 2a, and can recognize the scanning position of the measurement head part 3. FIG.

  By adopting a configuration in which this linear scale unit 11 is provided, the positions of a plurality of measurement points in the scanning section S can be clarified, and the measurement points before and after the relative movement of the auxiliary reference unit 2 can be measured with good reproducibility. It becomes an epoch-making straightness measuring device capable of measuring straightness with higher accuracy.

  A measurement example of a method for measuring the straightness of the measurement target surface Ms of the DUT 1 using this embodiment configured as described above will be described below.

First, as shown in FIG. 4, the position of the auxiliary reference part 2 before the auxiliary reference part 2 moves relative to the object to be measured 1 is defined as the first scanning position, and the auxiliary reference part 2 arranged at the first scanning position. of the predetermined range between the auxiliary reference plane Re and the surface to be measured Ms as the first scanning section S _1, the measuring head 3 of the air micrometer and scanning movement in the scanning direction of the first scanning section S _1, the The distance h ₁ from the first sensor unit 4 to the surface Ms to be measured and the auxiliary reference from the second sensor unit 5 at a large number of measurement points in one scanning section S ₁ , measurement points arranged at equal intervals in the measurement example in this measurement example. The distance h ₂ to the surface Re is measured for each measurement point, and the distance h ₁ from the first sensor unit 4 to the auxiliary reference surface Re and the second sensor unit 5 at a large number of measurement points in the first scanning section S _1. first scanning measuring a sum of the distance h ₂ to the auxiliary reference plane Re from Get the value.

Next, as shown in FIG. 9, the auxiliary reference portion 2 is moved relative to the device under test 1 by a predetermined distance in the scanning direction, in this measurement example, by a distance D, and the auxiliary reference portion with respect to the device under test 1 is moved. The position of the auxiliary reference portion 2 after the relative movement of the auxiliary reference portion 2 is set as the second scanning position, and a predetermined range between the auxiliary reference surface Re of the auxiliary reference portion 2 arranged at the second scanning position and the measured surface Ms is defined as the first range. a second scanning section S _2, the scanning direction of the second scanning section S ₂ of the measurement head 3 of the air micrometer and scan movement, a number of measurement points in the second scanning section S _2, at intervals D in this measurement example the distance h ₂ from the distance h ₁ between the second sensor portion 5 from the first sensor unit 4 in the measuring points arranged at regular intervals until the measured surface Ms to the auxiliary reference plane Re was measured for each measurement point, the first second scanning section S number of the measurement surface from the first sensor unit 4 in the measuring portion of ₂ M Obtaining a distance h ₁ between the second scan measurement is sum of the distance h ₂ from the second sensor unit 5 to the auxiliary reference plane Re up.

Thus from a first scan measurement and the first start point of the scanning segment S ₁ in the measurement surface Ms by calculating a difference value between the second scan measurements obtained by the end point of the second scanning section S ₂ Straightness is required.

  The straightness measurement using the present embodiment is a straightness measurement method in which the above-described measurement method is repeated to measure the straightness of the measurement surface Ms of the DUT 1.

In performing this repeated measures sought straightness from the first starting point of the scanning segment S ₁ as described above to the second end point of the scanning section S _2, to measure the start point of the next scan interval S in the first a method of moving the position to the auxiliary reference unit 2 which coincides with the end point of the second scanning section S _2, and a method of repeatedly measuring while moving always by a distance D relative movement amount of the auxiliary reference section 2 for DUT 1 Yes, the former is measured based on the shape of the auxiliary reference plane Re previously obtained, so that the measurement can be performed efficiently and the measurement time can be shortened. Since the measurement is repeated while confirming the shape repeatedly, the accuracy is improved.

Further, in the straightness measurement method using the above-described embodiment, for example, when the straightness measurement length of the measured surface Ms is L, the uncertainty of the straightness measurement result over the straightness measurement length L is as follows: The posture evaluation error when the auxiliary reference unit 2 moves relative to the DUT 1 by the distance D is represented by Δμ × L ² / 2D, where Δμ (at least the uncertainty of the resolution of the tilt measuring unit 6). Includes parabolic error.

  Therefore, if the straightness measurement length L is shorter than twice the scanning distance of the scanning section S, that is, L <2S, the movement amount of the auxiliary reference portion 2 is a large movement amount D of L / 2. , S / 10 or smaller movement amount d is moved twice, and a total of three scanning measurements are performed. At this time, the height of the point of L / 2 determined by the amount of movement D and the height of L / 2 obtained by connecting the moving amount d from the end with a broken line generally do not match.

  Therefore, the entire broken line obtained from the movement amount d is set to L = 0, and the inclination correction is performed so as to coincide with the point of L / 2 obtained from the movement amount D.

In this inclination correction, the inclination measuring section 6 provided in the auxiliary reference section 2 measures the inclination before and after the movement of the auxiliary reference section 2, and each scanning section S ₁ , S is based on each measured inclination. The first scanning measurement value and the second scanning measurement value obtained in ₂ are corrected.

By performing the inclination correction, 0 (in the present measurement example first start point of the scanning segment S ₁₎ can determine the interpolation point of ~L / 2 range.

  A second embodiment of the present invention will be described with reference to FIG.

  The present embodiment is a straightness measuring device used when the straightness measuring device shown in the first embodiment is used to measure the movement straightness of the machining table 15 of the machine tool.

  Specifically, a fixing tool 12 is provided in the measurement head unit 3, the scanning movement of the measurement head unit 3 is prevented, and the measurement head unit 3 is fixed at a predetermined position in the scanning section S. 2 is provided with a connection adapter part 13, and this connection adapter part 13 is detachably provided on the spindle tool holder 14 of the machine tool, and the connection adapter part 13 is connected to the spindle tool holder 14 of the machine tool to assist the reference. The part 2 is provided in the spindle tool holder 14 of the machine tool, and is provided so as to face the surface of the machining table 15 of the machine tool, and the machining table 15 of the machine tool is moved so that the measurement head is fixed. A scanning measurement value comprising a sum of a distance from the first sensor unit 4 of the unit 3 to the surface of the machining table and a distance from the second sensor unit 5 to the auxiliary reference plane Re is measured and calculated. It is a structure with a straightness measuring device so as to measure the movement straightness of the machining table 15 of the machine tool.

  That is, since the surface straightness of the machining table 15 of a machine tool is generally evaluated because the surface is straight, when measuring the surface straightness while moving the machining table 15, The measurement result will show a constant value, and if this measurement result shows a non-constant value, this is not because the machining table 15 is not straight, but the movement straightness of the machining table 15 is straight. Therefore, the present embodiment is a straightness measuring device for measuring the moving straightness of a moving object on which such a straight surface or a reference portion having a straight surface is placed.

  Specifically, in this embodiment, since the machining table 15 of the machine tool, that is, the measured object side 1 moves, the measurement head unit 3 does not need to be moved by scanning, and thus the measurement head unit 3 is fixed. A fixing tool 12 is provided so that the measuring head unit 3 is fixed.

  When the embodiment is attached to the spindle tool holder 14 of the machine tool, if there is a possibility that the leg 2c provided on the base support 2b interferes with the machining table 15, it is removed and attached. .

  Further, since the measurement head unit 3 is fixed and immovable, the second sensor unit 5 provided in the measurement head unit 3 always measures the same position on the auxiliary reference plane Re. The distance from the two sensor unit 5 to the auxiliary reference plane Re is constant.

  Therefore, the change in the scanning measurement value output from the measurement head unit 3 is a change in the distance from the first sensor unit 4 to the surface of the machining table 15, and it is known that the surface of the machining table 15 is straight. The change in the scanning measurement value output from the measuring head unit 3 indicates the vertical fluctuation when the machining table 15 of the machine tool is moved. That is, according to this embodiment, the movement of the machining table 15 of the machine tool is moved. The straightness can be measured.

  Note that the present invention is not limited to the first and second embodiments, and the specific configuration of each component can be appropriately designed.

DESCRIPTION OF SYMBOLS 1 Object to be measured 2 Auxiliary reference part 2a Base part 2b Base support part 3 Measurement head part 4 First sensor part 5 Second sensor part 6 Inclination measurement part 7 Scanning guide part
12 Fixture
13 Connection adapter section
14 Spindle tool holder
15 Machining table Ms Surface to be measured Re Auxiliary reference surface S Scan section S ₁ First scan section S ₂ Second scan section

Claims (10)

  A straightness measurement apparatus using an air micrometer, wherein a measurement target surface of an object to be measured and an auxiliary reference surface of an auxiliary reference portion are provided in an opposing state, and the measurement target surface and the auxiliary reference surface provided in the opposing state are provided A predetermined range between the two is defined as a scanning section, and the measurement head part of the air micrometer is provided movably in the scanning section, and the measurement head part is provided with a first sensor part at a position facing the surface to be measured. The second sensor unit is provided at a position facing the auxiliary reference plane, and the measurement head unit provided with the first sensor unit and the second sensor unit is scanned and moved in a predetermined direction, so that a large number of the scanning sections are provided. Configured to measure and calculate a scanning measurement value consisting of a sum of a distance from the first sensor unit to the measurement target surface and a distance from the second sensor unit to the auxiliary reference surface in the measurement location, Object to be measured and the auxiliary group And a scanning section after the auxiliary reference section or the measured object is relatively moved by a predetermined distance relative to the measured object or the auxiliary reference section. The straightness measuring device is configured to measure and calculate the straightness of the measured surface from the difference value between the respective scanning measurement values.   An inclination measuring unit is provided in the object to be measured or the auxiliary reference part, and a degree of inclination of the object to be measured or the auxiliary reference part before and after relative movement with respect to the auxiliary reference part or the object to be measured is measured. The straightness measuring apparatus according to claim 1, wherein the straightness measuring apparatus is configured to measure and calculate the straightness of the surface to be measured by correcting based on the degree.   The straightness according to any one of claims 1 and 2, further comprising a scanning guide unit that linearly moves the measurement head unit between the surface to be measured and the auxiliary reference surface. measuring device. The length of the measurement head portion in the scanning direction is X, the length in the width direction orthogonal to the scanning direction is Y, the thickness is T, the clearance between the measurement head portion and the surface to be measured is C ₁ , and the measurement the clearance between the head portion and the auxiliary reference plane and C _2, the maximum pitching angle at a state where the measuring head is tilted to the maximum back and forth relative to the scanning direction [theta] x, the measuring head is to the scanning direction Assuming that the maximum rolling angle when tilted to the left and right is θy, (T + C ₁ + C ₂ ) × (1 / COSθx−1) <necessary measurement accuracy or resolution, and (T + C ₁ + C ₂ ) × (1 / COSθy− The straightness measuring apparatus according to any one of claims 1 to 3, wherein the X, Y, T, C ₁ and C ₂ are set so that the required measurement accuracy or resolution is satisfied. .   The auxiliary reference portion has a structure in which a base portion having a lower surface as the auxiliary reference surface is installed on an opposing base support portion, and the base support portion is placed on the surface to be measured or the mounting object. The straightness measuring device according to any one of claims 1 to 4, wherein the straightness measuring device is configured to be movably mounted on the top.   The measuring head unit is provided with a fixture, the scanning movement of the measuring head unit is prevented and the measuring head unit is fixed at a predetermined position in the scanning section, and a connection adapter unit is provided in the auxiliary reference unit, The connection adapter part is configured to be detachably provided on a spindle tool holder of a machine tool, the auxiliary adapter part is provided on the spindle tool holder by connecting the connection adapter part to the spindle tool holder of the machine tool, and Provided in opposition to the surface of the machining table of the machine tool, and by moving the machining table, the distance from the first sensor portion of the measurement head portion in the fixed state to the surface of the machining table and the second sensor portion The movement straightness of the machining table is obtained by measuring and calculating a scanning measurement value consisting of a total value with the distance to the auxiliary reference plane. By being configured so as to measure the straightness measuring device according to any one of claims 1 to 5, wherein.   It is a straightness measuring method using the straightness measuring device of any one of Claims 1-5, Comprising: The to-be-measured surface of the said to-be-measured object and the auxiliary | assistant reference surface of the said auxiliary | assistant reference part are made to oppose. A predetermined range between the surface to be measured and the auxiliary reference surface provided in the facing state is set as the scanning section, and the measuring head portion of the air micrometer is provided movably in the scanning section. The unit provides the first sensor unit at a position facing the surface to be measured, and the second sensor unit at a position facing the auxiliary reference surface, and scans and moves the measurement head unit in a predetermined direction. Measuring and calculating the scanning measurement value composed of the sum of the distance from the first sensor unit to the surface to be measured and the distance from the second sensor unit to the auxiliary reference surface at a number of measurement points in the scanning section; The object to be measured and the auxiliary group Is provided so as to be movable relative to the object to be measured or from the difference value of the scanning measurement value in each scanning section before and after the relative movement of the auxiliary reference part or the object to be measured with respect to the auxiliary reference part. A straightness measurement method comprising measuring and calculating the straightness of a measurement surface.   A straightness measurement method using the straightness measurement apparatus according to any one of claims 1 to 5, wherein the auxiliary reference portion before the auxiliary reference portion moves relative to the object to be measured. The position is defined as a first scanning position, and a predetermined range between the auxiliary reference surface of the auxiliary reference portion disposed at the first scanning position and the measured surface is defined as a first scanning section, and the scanning direction of the first scanning section is The measurement head unit of the air micrometer is scanned and moved, and the distance from the first sensor unit to the surface to be measured and the second sensor unit to the auxiliary reference surface at a number of measurement points in the first scanning section. The distance is measured, and the total value of the distance from the first sensor unit to the auxiliary reference plane and the distance from the second sensor unit to the auxiliary reference plane at each measurement point is the first scanning measurement value. And obtained for the object to be measured The auxiliary reference portion is relatively moved by a predetermined distance in the scanning direction, and the position of the auxiliary reference portion after the auxiliary reference portion is relatively moved with respect to the object to be measured is defined as a second scanning position. A predetermined range between the auxiliary reference surface of the auxiliary reference portion and the surface to be measured is a second scanning section, and the measuring head unit of the air micrometer is scanned and moved in the scanning direction of the second scanning section, Measure the distance from the first sensor unit to the surface to be measured and the distance from the second sensor unit to the auxiliary reference surface at a number of measurement points in the second scanning section. A total value of the distance from the first sensor unit to the measured surface and the distance from the second sensor unit to the auxiliary reference surface is obtained as a second scanning measurement value, and the first scanning measurement value and the second measurement value are obtained. Previous from the difference from the scan measurement Straightness measuring method characterized by calculating the straightness of the surface to be measured.   Measure the inclination before and after the auxiliary reference part moves relative to the part to be measured, determine a relative inclination based on the measured inclination, and use the relative inclination to determine the first scan measurement value and The straightness measurement method according to claim 8, wherein a straightness of the measurement target surface Ms is calculated by correcting a difference value from the second scanning measurement value.   A straightness measurement method using the straightness measurement apparatus according to claim 6, wherein a fixture is provided on the measurement head unit so that the measurement head unit is fixed at a predetermined position in the scanning section. A connecting adapter part is provided in the auxiliary reference part, the connecting adapter part is connected to a spindle tool holder of a machine tool, and the auxiliary reference part is provided in the spindle tool holder 1, and in a state of being opposed to the surface of the machining table of the machine tool. A total value of a distance from the first sensor unit of the measurement head unit in the fixed state to the surface of the machining table and a distance from the second sensor unit to the auxiliary reference surface by moving the machining table A straightness measuring method comprising: measuring and calculating a scanning measurement value comprising: measuring and calculating the movement straightness of the machining table.

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