JP2007198944A - Deflection measuring instrument, and deflection measuring method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To carry out deflection measurement evaluation in a position of requiring the true deflection measurement evaluation, i.e., in the vicinity of working position, in a deflection measuring instrument. <P>SOLUTION: This deflection measuring instrument is provided with the first displacement gage for detecting a surface position of a member, the second displacement gage for detecting a surface position in a position separated by a prescribed distance from the surface position of the member detected by the first displacement gage, along a rotary shaft direction of a motor part, and a deflection amount calculating part for calculating a deflection amount in rotation of the member other end part, based on detection results in the first displacement gage and the second displacement gage before and after a holder part is rotated by a prescribed angle by the motor part. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a shake measuring apparatus and a shake measuring method for measuring a shake amount of a member rotating around a rotation axis.

A conventional run-out measuring device has an eddy current sensor, and a clamp abnormality is measured by measuring a change in a gap between the eddy current sensor and a flange portion of a tool holder that engages a spindle supported by a headstock. The presence or absence of this was determined (for example, refer patent document 1).
JP 2002-331442 A (FIG. 1)

  In the conventional run-out measuring device, the run-out amount calculated from the measurement point is evaluated as the run-out amount of the machining position that needs to be truly run-away away from the measurement point. However, there is a problem that the machining result does not satisfy the required specifications because the deflection amount at the machining position is large.

  The present invention has been made to solve the above-described problems, and provides a shake measuring device that can evaluate the shake amount in the vicinity of a machining position.

  The shake measuring apparatus according to the present invention includes a holder unit that holds one end of a member, a motor unit that rotates the holder unit, a first displacement meter that measures the surface position of the member, and a first displacement meter A second displacement meter that measures a surface position at a predetermined distance from the surface position of the member to be rotated in the rotation axis direction of the motor unit, and a first displacement before and after the motor unit rotates the holder unit by a predetermined angle. And an arithmetic unit that calculates a deflection amount during rotation of the other end portion of the member based on the measurement results of the meter and the second displacement meter.

  According to the present invention, it is possible to evaluate the amount of deflection in the vicinity of the machining position, which is a position that truly requires measurement and evaluation. Therefore, it is possible to reliably detect defects in the processing result due to deformation of a member such as a tool or a workpiece, poor attachment to the holder, poor attachment of the holder to the motor, or vibration of the motor.

Embodiment 1 FIG.
FIG. 1 shows a shake measuring apparatus according to Embodiment 1 for carrying out the present invention. In FIG. 1, one end 1 a of an end mill 1 as a member is held by a holder 2. The holder 2 is inserted into the mounting hole of the motor 3 and is firmly fixed. A grinding wheel 11 as a tool is inserted into an attachment hole of another motor 12 and is firmly fixed. These two motors 3 and 13 are fixed to a table (not shown) of the grinding apparatus, the two motors move relatively, and the end mill 1 is processed by the grinding wheel 11. That is, the blade 1b of the end mill 1 which is the other end of the member is reground, and the sharpness of the blade is regenerated.

  On the other hand, as the first displacement meter and the second displacement meter, the contacts 21a and 21b are set apart from each other by a predetermined distance L in the displacement meter 20, and the positions of two points can be measured simultaneously. . Further, the contact 21a and the contact 21b are different in length by T. The measured value of the displacement meter 20 is transmitted to the arithmetic device 30, calculates the amount of shake at the other end of the end mill 1, generates a shake amount evaluation result signal, and transmits it to the NC device 40. The NC device 40 performs operations such as machining start and re-measurement based on the deflection amount evaluation result signal. Furthermore, the displacement meter 20 is fixed to the rotary table 22. The displacement meter 20 is in a position indicated by a solid line when measuring the amount of deflection, and is retracted to a position indicated by a dotted line so that a contact or the like does not interfere with the workpiece or the like when the end mill 1 is ground. To do.

  Further, the holder 2 is provided with a gap portion 2a in a portion that grips the end mill 1 corresponding to the contacts 21a and 21b. When the holder 2 holds the end mill 1, the gap portion 2a causes the end mill 1 to It is comprised so that the surface of may be exposed. A total of eight gaps 2 a are provided, two at a predetermined distance L in the direction of the rotation axis of the motor 3 and four at every 90 degrees in the rotation angle direction of the motor 3.

  Further, here, for convenience, the rotation axis direction of the motor 3 is the x-axis, and the movement directions of the contacts 21a and 21b installed in the shake amount displacement meter 20 at the time of the shake amount measurement are the y-axis, the x-axis, and the y-axis perpendicular Let the direction be the z-axis.

  Furthermore, here, a shrink-fitted holder is used as the holder 2 and a plunger-type contact displacement meter is used as the contacts 21a and 21b. However, the shake measuring device of the present invention has these configurations. Not limited.

  Next, the operation of the shake measuring apparatus configured as described above will be described with reference to FIG. FIG. 2 is a flowchart showing the operation of the shake measuring apparatus according to the first embodiment. As shown in FIG. 2, the measurement evaluation of the shake amount is divided into three stages: measurement preparation (st1), surface position measurement (st2), and shake evaluation (st3). Hereinafter, the operation in each stage will be described in detail.

  First, consider a case where the displacement meter 20 is in a standby state as indicated by the dotted line in FIG. In order to enter a measurement state for measuring the shake amount from this state, the rotary table 22 rotates and the displacement meter moves to the position indicated by the solid line in FIG. 1 (st101). Next, the holder 2 is rotated by the motor 3 so that the gap 2a provided in the holder 2 is in front of the contacts 21a and 21b (st102). Preparation for measurement is completed by the operations of st101 and st102 (st1).

  Next, the displacement meter 20 advances in the direction of the y-axis holder 2 (st201), and contacts 21a and 21b provided on the displacement meter 20 are exposed on the surface of the end mill 1 exposed from the gap 2a provided on the holder 2. The y coordinate of the surface position is measured by touching (st202). The measurement value measured by the displacement meter 20 is transmitted to the arithmetic unit 30, and the displacement meter 20 moves backward to return to the position where measurement preparation is completed (st203). When the position of the displacement meter 20 returns, the motor 3 rotates 90 degrees (st204). Since the holder 2 is provided with the gap 2a by 90 degrees in the rotation angle direction of the motor 3, after the motor 3 is rotated 90 degrees, a different gap is positioned in front of the contacts 21a and 21b. . As described above, the operation of st201 to st204 is repeated four times, the y coordinate of the surface position of the end mill 1 exposed from the gap 2a before and after rotating by 90 degrees is measured, and each measurement result is transmitted to the computing device 30 ( st205). The surface position measurement is completed by the operations of st201 to st205 (st2). When the rotation angle position at the time of first measuring the surface position is 0 degree, the measurement value of the contact 21a at the rotation angle position 0 degree is Ja1, the measurement value of the contact 21b is Jb1, and the rotation angle position 90 The measured values of the contact 21a at degrees, 180 degrees, and 270 degrees are Ja2, Ja3, Ja4, and the measured values of the contact 21b are Jb2, Jb3, and Jb4, respectively.

  Next, a shake evaluation method will be described. First, the phenomenon of shake will be described with reference to FIG. FIG. 3 is a view when the end mill 1 is viewed from the x-axis direction at rotation angle positions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees. 3, parts corresponding to those in FIG. 1 are given the same numbers. As shown in FIG. 3, when the center 1M of the end mill 1 is deviated from the rotation center 3M of the motor 3 by a predetermined distance (this predetermined distance is hereinafter referred to as eccentricity), when the motor 3 rotates, the end mill 1 The center 1M of the motor rotates about the rotation center 3M of the motor. Such a phenomenon is called shake. Here, when the y-coordinate of the position of the surface 1aA of the end mill 1 exposed from the gap 2a is measured by the contact 21a, the measured value is different depending on the rotation angle position. That is, Ja1, Ja2, Ja3, and Ja4 have different values. The same applies to the measured value of the contact 21b.

  Accordingly, the measured value of the contact 21a at each rotation angle position is a value on a circular orbit as shown in FIG. As is clear from FIG. 3, the circular orbit shown in FIG. 4 is the same as the circular orbit of the center 1M of the end mill 1. Therefore, the radius H of the circular orbit shown in FIG. 4 is the same as the eccentricity, and the deflection F is the diameter (2 × H) of the circular orbit as defined by the JIS standard.

Next, a method for calculating the shake amount in the arithmetic unit 30 will be described with reference to FIG. The center coordinate of the circular orbit shown in FIG. 4 is a position O that is moved from the center of deflection by the radius R of the cross section of the end mill 1 in the y-axis direction. Since the y coordinates (Ja1 to Ja4) measured by the displacement meter 20 are measured with the position shifted from the center of the circular orbit shown in FIG. 4 as the origin, the coordinates are corrected to the coordinate values with the position O as the origin. There is a need. Here, the y-coordinate Oy of the position O is obtained by Expression (1).
Oy = (Ja1 + Ja2 + Ja3 + Ja4) / 4 (1)
Therefore, the y-coordinates Ya1 to Ya4 of the surface of the end mill 1 exposed from the gap 2a when the position O corresponding to Ja1 to Ja4 is set as the origin are obtained by the equations (2) to (5).
Ya1 = Ja1-Oy (2)
Ya2 = Ja2-Oy (3)
Ya3 = Ja3-Oy (4)
Ya4 = Ja4-Oy (5)
In addition, Za1 to Za4 in FIG. 4 are z coordinates when the position O is the origin, similarly to Ya1 to Ya4. However, the coordinate values of Za1 to Za4 are coordinate values used for convenience of explanation, and there is no need to actually measure them.

In order to calculate the shake amount F (2 × H) using Ya1 to Ya4, as is apparent from FIG. 4, the phase angle g when the rotational angle position is 0 degrees is used to obtain the shake amount F (2 × H). Can do.
Ya1 = H × cos (g) (6)
However, since the phase angle g is an unknown amount, the shake amount cannot be obtained using only the equation (6). Therefore, using the y-coordinate Ya2 of the surface position when the rotation angle position is 90 degrees, Equation (7) is obtained from the trigonometric function formula.
Ya2 = H × cos (g + 90 degrees)
= H × (−sin (g))
= -Za (7)
That is, the absolute value of Ya2 is equal to the z component Za1 when the rotation angle position is 0 degree. Therefore, the equation (8) is established from the Pythagorean theorem.
(F / 2) ² = H ² = Ya1 ² + Za1 ²
= Ya1 ² + Ya2 ² (8)
As is apparent from the equation (8), the shake amount F can be calculated from the y coordinates Ya1 and Ya2 when the rotation angle position is 0 degree and 90 degrees. That is, it is possible to calculate the shake amount F without calculating the phase angle g using only two measured values of the displacement meter 20.

  However, the shake amount calculated from only Ya1 and Ya2 may cause a large error from the actual shake amount due to the influence of the measurement accuracy of the displacement meter 20, the contamination of the surface of the end mill 1, and the like. Since the four values Ya1 to Ya4 have already been calculated as the y-coordinates of the surface, in addition to the calculation of the shake amount by the combination of (Ya1, Ya2) described above, (Ya2, Ya3), (Ya3, Ya4) , (Ya4, Ya1) can detect the shake amount. When the shake amounts calculated by the above four combinations are Fa1, Fa2, Fa3, and Fa4, the arithmetic unit 30 records these values and the eccentricities Ha1, Ha2, Ha3, and Ha4 corresponding to these shake amounts. Keep it. It is also possible to calculate the average value Fa of Fa1 to Fa4, set Fa as the amount of shake measured by the contact 21a, and obtain the deviation of Fa1 to Fa4 to confirm the validity of the measurement accuracy.

  Similarly, based on the y coordinates Jb1 to Jb4 of the surface of the end mill 1 measured by the contact 21b, four deflection amounts Fb1 to Fb4 and eccentricity Hb1 to Hb4 corresponding to these deflection amounts are calculated and recorded. Keep it.

Next, a method for obtaining the shake amount in the vicinity of the machining position that really needs to be evaluated using the average values Fa and Fb of these shake amounts will be described with reference to FIG. FIG. 5 is a sectional view of the end mill 1 as viewed from the z-axis direction. In FIG. 5, the center axis 1x of the end mill 1 is fixed to the holder 2 with an eccentricity and an angle f with respect to the rotating shaft 3x of the motor. The eccentricity Ha (= Fa / 2) calculated based on the measured value of the contact 21a is the eccentricity at the measurement circumference 1aA, and the eccentricity Hb calculated based on the measured value of the contact 21b (= Fb / 2). Is the eccentricity at the measurement circumference 1aB. These eccentricities Ha and Hb are different from the eccentricity Hc in the vicinity of the machining position 1b that really needs to be evaluated because the deflection angle f exists, and this is necessary to evaluate the deflection amount. It is necessary to calculate Hc. Here, when Hc1 is the eccentricity in the vicinity of the machining position based on the eccentricity Ha1 and Hb1, and M is the distance from the measurement circumference 1aA to the vicinity of the machining position, Hc1 is geometrically calculated by the equation (9). It is possible.
Hc1 = Ha1 + (| Hb1-Ha1 | / L) × (M / L) (9)
Similarly, when Hc2 to Hc4 are eccentricity in the vicinity of the machining position based on Ha2 to Ha4 and Hb2 to Hb4, respectively, Hc2 to Hc4 are calculated by equations (10) to (12).
Hc2 = Ha2 + (| Hb2-Ha2 | / L) × (M / L) (10)
Hc3 = Ha3 + (| Hb3-Ha3 | / L) × (M / L) (11)
Hc4 = Ha4 + (| Hb4-Ha4 | / L) × (M / L) (12)
By taking the average value of the eccentricities of Hc1 to Hc4 calculated as described above, the eccentricity Hc near the machining position is obtained. Further, by doubling Hc, it is possible to obtain a deflection amount Fc near the machining position (st301). Further, the standard deviation σ of Hc1 to Hc4 is also calculated.

  Next, the shake amount Fr required as the rotation specification of the measurement target (end mill, etc.) and its reliability (yield, etc.) are compared with the shake amount Fc and the standard deviation σ calculated as described above to determine the shake amount. Evaluation is performed, a shake amount evaluation result signal is generated, and transmitted to the NC device 40 (st302). When receiving information that Fc or σ is larger than a predetermined value as a shake amount evaluation result signal, the NC device 40 remeasures the shake amount Fc or reattaches the end mill 1. When information indicating that Fc or σ is smaller than a predetermined value is received as a shake amount evaluation result signal, it is considered that a processing execution permission signal has been transmitted, and processing of the end mill 1 is started. As described above, the shake evaluation is completed by performing st301 and st302 (st3).

  In this way, since it becomes possible to evaluate the amount of deflection near the machining position, which is a position where measurement and evaluation are truly necessary, deformation of a member such as a tool or a workpiece, improper attachment to the holder, or attachment of the holder to the motor It is possible to reliably detect defects in processing results due to mounting failure, motor runout, etc. with high accuracy.

  In Embodiment 1, the case where a cylindrical member is used as the end mill 1 has been described. However, the shape of the end mill 1 is not limited to this, and may be a conical member. In the case of a rotating body, the touch amount can be measured by the shake amount measuring device.

  Further, the configuration in which the holder 2 is provided with the two rows of gaps 2a with respect to the rotation angle of the motor 3 has been described. However, the configuration is such that the surface position is detected at a portion not gripped by the holder 2 of the end mill 1. For example, the gap 2a is not necessarily provided.

  Moreover, although the displacement meter 20 is configured to have two contacts, only one contact may be provided. In this case, after calculating the y coordinate of the surface position of the end mill 1 with one contact, the displacement meter 20 may be moved by the distance L in the x-axis direction and the y coordinate of the surface position may be calculated again.

  Furthermore, the method of calculating the amount of shake by rotating the end mill 1 360 × 1 degrees with the four rotation angle positions of 0 degrees, 90 degrees, 180 degrees, and 270 degrees as one set has been described. A plurality of rotation angle positions such as 360 × 2 degrees or 360 × 3 degrees may be used by using a plurality of rotation angle positions. In this case, since the data amount of the measurement value increases, it is possible to further improve the measurement accuracy. Also, the same effect can be obtained by setting the rotation angle position in increments of 30 degrees instead of in increments of 90 degrees.

  Furthermore, in the deflection amount calculation apparatus of the first embodiment, the protruding amounts of the contactor 21a and the contactor 21b are installed with a difference of the length T, so that the y-coordinate of the surface position of the end mill 1 is set. There is also a difference in the measured values by T. As a result, the correspondence between the measured value of the contact 21a or the contact 21b is clarified, and mistakes such as misunderstandings can be reduced in determination of measurement errors. The length of T is preferably 3 or 5 mm for ease of assembly adjustment, but is not limited to such a value.

It is a figure which shows the shake amount measuring apparatus in this Embodiment 1. FIG. FIG. 6 is a flowchart showing the operation of the shake amount measuring apparatus in the first embodiment. It is the figure which looked at the end mill in this Embodiment 1 from the x-axis direction. It is a figure which shows the locus | trajectory of the surface position of an end mill in this Embodiment 1. FIG. It is the figure which looked at the end mill in this Embodiment 1 from the y-axis direction.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 End mill, 2 Holder, 2a Gap part, 3 Motor, 20 Displacement meter, 21a, b Contact, 30 Arithmetic unit

Claims (5)

A holder for gripping one end of the member;
A motor unit for rotating the holder unit;
A first displacement meter for measuring a surface position of the member;
A second displacement meter that measures a surface position at a predetermined distance from a surface position of the member measured by the first displacement meter in a rotation axis direction of the motor unit;
Based on the measurement results of the first displacement meter and the second displacement meter before and after the motor portion rotates the holder portion by a predetermined angle, the amount of deflection during rotation of the other end portion of the member is calculated. An arithmetic unit;
A shake measuring device characterized by comprising: The holder has a gap in a portion where the member is gripped,
The shake measuring apparatus according to claim 1, wherein the displacement meter measures a surface position of the member exposed from the gap. 3. The shake measuring device according to claim 1, wherein the first displacement meter and the second displacement meter have different lengths and are plunger-type contact displacement meters. 4. The shake measuring apparatus according to any one of claims 1 to 3, wherein the predetermined angle by which the motor unit rotates the holder unit is 90 degrees. In the shake amount measuring method for measuring the shake amount of the other end portion during rotation of the member whose one end portion is held by the holder portion that rotates by the motor portion,
A first surface position measuring step of measuring surface positions of two points separated from each other by a predetermined distance in a rotation axis direction of the motor of the member held by the holder;
A rotation step of rotating the holder part by a predetermined angle by the motor part;
A second surface position for measuring the surface positions of two points separated by a predetermined distance in the rotation axis direction of the motor of the member held by the holder after the holder portion is rotated by a predetermined angle by the rotation step. Measuring steps;
A shake amount calculating step of calculating a shake amount during rotation of the other end of the member based on the surface position measured in the first surface position measuring step and the second surface position measuring step;
A method for measuring a shake amount, comprising:

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