JP5186976B2 - Measuring tool adjustment method, measuring device angle detection method, detection result correction method by measuring device, and machine tool equipped with a thread groove detection device - Google Patents

Description

  The present invention relates to a method for adjusting a measuring element in which a measuring element is brought into contact with the cylindrical part from a direction intersecting the rotating axis with respect to a workpiece having a cylindrical part at least partially held rotatably around a predetermined rotating axis. The present invention relates to a method for detecting an angle between a guide means for guiding the measuring element and a predetermined reference surface, a correction method for a detection result by the measuring element, and a machine tool including a screw groove detecting device using the measuring element.

Conventionally, when forming a screw groove on at least a part of a cylindrical surface of a cylindrical workpiece, first, rough machining such as Waring is performed to form a rough shape of the screw groove, and then the roughened screw groove is finish-ground. doing. Therefore, when performing finish grinding, it is necessary to determine the position of the grindstone (processing tool) in front of the screw groove position, and it is necessary to accurately measure the position of the screw groove.
Therefore, in the prior art described in Patent Document 1, the measuring element is connected to and integrated with a support base of a machining tool (in this case, a grindstone), and the measurement is performed on the opposite side of the grindstone with the work on which the screw shaft is formed. A probe is arranged, and the position of the screw shaft is measured by bringing the probe into contact with the screw groove at a position delayed by a half lead from the machining point of the machining tool.
JP-A-1-295713

In the prior art described in Patent Document 1, the measuring element is moved along the single-axis table for measuring element positioning, and the measuring element is brought into contact with the thread groove of the workpiece. Here, unless the measuring element is moved so that the extension of the movement locus of the measuring element accurately intersects the workpiece rotation axis, the accurate screw groove position cannot be measured. However, the cited document 1 does not describe a specific method for adjusting the extension of the movement locus of the tracing stylus so as to accurately intersect the workpiece rotation axis.
Moreover, in patent document 1, the contactor which contacts a workpiece | work is hold | maintained with two sets of parallel leaf | plate springs. When the contactor is pressed against the workpiece and one pair of parallel leaf springs is bent (when the arc is moved), the vertical position of the contactor is slightly shifted from the position that exactly intersects the workpiece rotation axis. Due to the deviation, there is a possibility that the position of the thread groove cannot be measured accurately. Similarly, when the other set of parallel leaf springs is bent in the lead direction (axial direction) of the thread groove (when moved in a circular arc), the vertical position of the contactor is also slightly shifted, and it is accurate with the workpiece rotation axis. Therefore, there is a possibility that the position of the screw groove cannot be measured accurately.
The present invention was devised in view of the above points, and in a mechanism for moving a probe in a direction intersecting the workpiece rotation axis, the movement direction (guide direction) of the probe is accurately set to the workpiece rotation axis. An adjustment method (so-called centering method) of a probe that adjusts so as to intersect, an angle detection method (so-called reference extraction method) that obtains an accurate angle in the moving direction of the probe, a correction method of a detection result by the probe, and It is an object of the present invention to provide a machine tool including a thread groove detection device using the probe.

As means for solving the above-mentioned problems, a first invention of the present invention is a method for adjusting a probe as described in claim 1.
The method of adjusting a stylus according to claim 1, wherein a workpiece having a cylindrical portion at least partially held rotatably around a predetermined rotation axis is measured on the cylindrical portion from a direction intersecting the rotation axis. A method for adjusting a measuring element in contact with a measuring element, wherein the measuring element is attached to guiding means that substantially intersects the rotation axis and can move forward and backward in a guiding direction in which the direction can be finely adjusted.
Further, at least a plurality of cylindrical portions having different diameters are provided on a concentric axis, and the cylindrical surface of each cylindrical portion is formed in a direction parallel to the concentric axis and on a single plane passing through the concentric axis. A master work having a reference groove formed to be positioned is held around the rotation axis so that the rotation axis and the concentric axis coincide with each other, and the measuring element and the reference groove are opposed to each other. Set the rotation angle of the master work.
Then, the measuring element is moved relative to the master work in a direction parallel to the rotation axis so that the reference groove of the cylindrical portion selected from the master work faces the measuring element. After that, the rotation angle of the master work adjusted so that the measuring element contacts the reference groove by moving the measuring element toward the reference groove using the guide means, and at least two cylindrical portions The guide direction of the guide means is adjusted so that the probe contacts the reference grooves of at least two cylindrical portions at the same rotation angle in the master work. This is a method for adjusting a probe.

A second invention of the present invention is a method for detecting an angle of a probe as described in claim 2.
According to a second aspect of the present invention, there is provided a method for detecting the angle of a stylus, wherein a workpiece having a cylindrical portion at least partially held rotatably around a predetermined rotation axis is moved back and forth in a guide direction intersecting the rotation axis. This is a method for detecting the angle of a measuring element that is attached to a possible guiding means and is brought into contact with the cylindrical portion.
Further, at least part of the cylindrical part has a cylindrical part, and a part of the cylindrical part is formed with a plane part parallel to the axis of the cylindrical part, and the cylindrical surface of the cylindrical part is parallel to the axis of the cylindrical part. A master work in which a reference groove is formed is held around the rotation axis so that the rotation axis and the axis of the cylindrical portion coincide with each other, and a perpendicular drawn from the axis of the cylindrical portion to the planar portion, and the cylinder The reference plane set in advance so as to be parallel to the rotation axis and the plane part of the master work are parallel to each other, with the angle formed by the perpendicular formed from the axis of the part to the reference groove as an arrangement angle The rotation angle of the master work is adjusted to the initial angle.
Then, based on the rotation angle from the initial angle in the master work adjusted so that the probe touches the reference groove when the probe is moved in the guide direction, and the arrangement angle, the reference angle It is a method for detecting the angle of the stylus, which detects an angle of the guide direction with respect to a surface.

The third invention of the present invention is a method for correcting a detection result by a probe as described in claim 3.
According to a third aspect of the present invention, there is provided a method for correcting a detection result by using a stylus having at least a plurality of cylindrical portions having different diameters on a concentric axis, and the cylindrical surface of each cylindrical portion is formed in a direction parallel to the concentric axis. And a reference groove formed so as to be located on the same plane passing through the concentric axis, and a master portion in which a plane portion parallel to the concentric axis is formed in a part of at least one of the cylindrical portions. Use work.
2. The measuring element adjustment method according to claim 1, wherein an angle formed by a perpendicular line extending from the concentric axis to the planar portion and a perpendicular line extending from the concentric axis to the reference groove is an arrangement angle. After adjusting the guide direction of the guide means, detected using the measuring element based on the angle of the guiding direction with respect to the reference plane, detected using the angle detecting method of the measuring element according to claim 2. This is a method for correcting a detection result by a measuring element, which corrects the detection result.

According to a fourth aspect of the present invention, there is provided a machine tool provided with the thread groove detecting device according to the fourth aspect.
A machine tool comprising the thread groove detection device according to claim 4, wherein a thread groove detection for detecting a position of a thread groove formed on at least a part of a cylindrical surface of a work held rotatably about a predetermined rotation axis. A machine tool comprising a device, a measuring element contacting the screw groove, a floating means for holding the measuring element so as to be reciprocally movable in a lead direction parallel to the rotating shaft, and a rotating shaft An urging means for urging the measuring element in the intersecting guide direction, a lead side position detecting means capable of detecting the position of the measuring element in the lead direction, and a position of the measuring element in the guiding direction can be detected Radial position detecting means, guide means capable of moving the measuring element forward and backward in a guiding direction substantially intersecting the rotation axis, and finely adjusting the guiding direction, and a processing tool for grinding the screw groove , Comprising a.
And after adjusting the guide direction of the said guide means using the adjustment method of the measuring element of Claim 1, the said measuring element is pressed on the thread groove of the said work so that it may cross | intersect the said rotating shaft, The said diameter side The position detecting means is used to detect that the measuring element has entered the screw groove, and the lead side position detecting means is used to detect the position in the lead direction of the measuring element, and the position of the screw groove is determined. To detect.
Further, the position of the probe in the lead direction after the workpiece is rotated by a predetermined angle is detected, and the pitch of the screw groove is obtained based on the amount of movement of the probe in the lead direction with respect to the predetermined angle. The position of the detected screw groove is corrected based on the angle of the guide direction with respect to the reference surface detected using the angle detection method of the stylus according to claim 2 and the obtained pitch of the screw groove. To do.
And a screw groove detecting device for positioning the machining tool movable relative to the workpiece in a direction parallel to the reference plane and grinding the screw groove at the corrected screw groove position. It is a machine tool.

  According to the method for adjusting a tracing stylus according to claim 1, by using a master work having a plurality of cylindrical portions having different diameters on which a reference groove is formed on the same axis, a guide direction for moving the tracing styling is a work rotation. It is convenient because it can be finely adjusted more accurately and easily so as to cross the axis.

  In addition, according to the method for detecting the angle of the stylus according to claim 2, by using a master work having a cylindrical part in which a reference groove and a flat part are formed, a preset reference surface (parallel to the work rotation axis) is used. ) With respect to the guiding direction (the moving direction of the measuring element) can be detected more accurately and more easily.

Further, according to the correction method of the detection result by the stylus according to claim 3, it intersects the workpiece rotation axis more accurately and more easily with respect to a preset reference plane (parallel to the workpiece rotation axis). In addition, the angle of the adjusted guide in the guide direction can be detected more accurately and more easily.
For example, when grinding the thread groove by measuring the position in the lead direction of the thread groove (position in the axial direction of the workpiece rotation axis) with a probe, the angle between the reference surface and the guide direction and the pitch of the thread groove are determined. Based on this, by correcting the position in the lead direction at the grinding location (correcting the detection result), the position in the lead direction of the screw groove at the processing location can be obtained more accurately.

Further, according to the machine tool including the thread groove detection device according to claim 4, it is possible to more accurately and more easily adjust the guide direction of the probe so as to intersect the workpiece rotation axis, Furthermore, the angle of the guide direction of the probe relative to the reference surface can be detected more accurately and more easily.
Then, when grinding a thread groove using a machining tool having a machining point at a position in the reference plane, the position of the thread groove in the lead direction (position in the axial direction of the workpiece rotation axis) and pitch are measured using a measuring element. Measure the position of the thread groove (position in the lead direction) where the machining tool should be positioned more accurately based on the position of the thread groove, the pitch of the thread groove, and the angle between the reference plane and the guide direction. Can be sought.

The best mode for carrying out the present invention will be described below with reference to the drawings. FIG. 1A shows a schematic external view (plan view) of an embodiment of a machine tool 1 provided with a thread groove detecting device 80, and FIG. 1B shows the machine tool 1 (in this case, The example of the schematic external view (side view) of a screw grinding machine is shown. In FIG. 1B, the spindle devices 30R, 30L and the like are omitted in order to explain the positional relationship between the workpiece W, the contactor 83, and the grindstone 22.
2A and 2B show how the workpiece W is supported using the spindle devices 30L and 30R.
In all the drawings, the X axis, the Y axis, and the Z axis are orthogonal to each other, the Y axis indicates a vertically upward direction, the Z axis indicates a horizontal direction parallel to the workpiece rotation axis CW, and the X axis Indicates a horizontal direction orthogonal to the Z-axis.

● [Configuration of machine tool 1 (FIGS. 1 and 2)]
As shown in FIGS. 1A and 1B, and FIGS. 2A and 2B, the machine tool 1 has spindle devices 30L and 30R facing each other, and the spindle device 30L is a linear guide GL. The main shaft device 30R is movable along the linear guide GR in the Z-axis direction.
The control means 50 (control device) outputs drive signals to the Z-axis direction drive motors 30LM, 30RM for the spindle devices 30L, 30R, takes in detection signals from the detection means 30LE, 30RE (encoders, etc.), and takes the spindle device 30L. , 30R in the Z-axis direction, the moving speed, and the like can be controlled. For example, as shown in FIGS. 2A and 2B, the Z-axis direction drive motor 30LM (30RM) rotates the ball screw BL (BR) and is fitted to the ball screw BL (BR) with a nut or the like. CL (CR) is moved, and the spindle device 30L (30R) connected to the arm CL (CR) is moved.

The machine tool 1 is mounted with a grindstone table 10 that can move in the Z-axis direction along the linear guide GZ. A grindstone table 20 that is movable in the X-axis direction with respect to the grindstone table 10 along the linear guide GX is placed on the grindstone table 10. The grindstone table 20 is provided with a grindstone drive motor 21 and a grindstone 22 (corresponding to a processing tool).
The control means 50 outputs a drive signal to the Z-axis direction drive motor 10M for the grinding wheel base 10, takes in a detection signal from the detection means 10E (encoder, etc.), and the position and moving speed of the grinding wheel base 10 in the Z-axis direction. Can be controlled. Similarly, the control means 50 outputs a drive signal to the X-axis direction drive motor 20M for the grindstone table 20, takes in a detection signal from the detection means 20E, and the position and moving speed of the grindstone table 20 in the X-axis direction. Can be controlled, and a drive signal can be output to the grindstone drive motor 21 to control the rotation of the grindstone 22. If the detection means is provided in the grindstone drive motor 21, the rotation speed of the grindstone 22 can be controlled.
Further, in the example of the machine tool 1 shown in FIG. 1A, a truing device 60 for forming the grindstone 22 on the spindle device 30L is provided.

Further, the machine tool 1 includes a contactor 83 (corresponding to a measuring element) to be brought into contact with a thread groove of a threaded portion K formed on at least a part of a cylindrical surface of a workpiece W having at least a part of a cylindrical part. A thread groove detection device 80 comprising a holding means 81 for holding the contactor 83 and a detecting body moving means 82 (corresponding to a guide means) capable of moving the holding means 81 in a direction orthogonal to the workpiece rotation axis CW. It is provided on the support body 84 (see FIG. 1B).
In the example shown in FIG. 1B, the workpiece rotation axis CW and the grindstone rotation axis CT are set on the same horizontal plane (reference plane STM which is the XZ plane), and the contactor 83 is in contact with the grindstone 22. The workpiece W is provided at a position substantially opposite to the workpiece W, and is disposed so as to be orthogonal to the workpiece rotation axis CW at an angle θ with respect to the reference plane STM.
For this reason, the screw groove position (position in the Z-axis direction) detected by the contactor 83 is corrected based on the angle θ (for example, when the angle θ is 150 degrees, the pitch of the screw groove ( The position obtained by adding 150 degrees / 360 degrees (or the position obtained by subtracting) of the interval) is the position of the thread groove facing the grindstone 22 (or after detecting the position of the thread groove, the workpiece W is rotated by an angle θ. The surface detected in this manner is opposed to the grindstone 22).
The “position of the screw groove” refers to the “position of the center of the screw groove”.

  FIG. 1C shows an example of the appearance of the workpiece W. The workpiece W targeted by the machine tool 1 described in the present embodiment is a workpiece W in which screw grooves are formed on at least a part of the cylindrical surface of the workpiece W. FIG. 1C shows the appearance of an EPS (Electric Power Steering) steering rod that matches the above-described subject content. The steering rod includes a rack portion in addition to a screw portion K in which a thread groove is formed. The rack portion KR (a shape in which a part of the cylindrical surface is planar and a groove into which the pinion gear is fitted) is formed in the & pinion structure.

  The spindle device 30L includes a spindle stock 31L, a spindle portion 32L that rotates around a workpiece rotation axis, and a chuck claw 34L that rotates integrally with the spindle portion 32L and can support the cylindrical surface of the inserted workpiece W. And the chuck portion 33L. Further, the spindle portion 32L and the chuck portion 33L are provided coaxially (on the workpiece rotation axis), and a hole portion having a diameter capable of inserting the workpiece W in the Z-axis direction is formed. The control means 50 can control the opening and closing of the chuck pawl 34L, and can control the rotation of the spindle portion 32L. Further, the spindle device 30R, the spindle stock 31R, the spindle portion 32R, the chuck portion 33R, and the chuck pawl 34R are the same as the spindle device 30L described above, and thus the description thereof is omitted.

Here, in the case of the workpiece W shown in FIG. 1C, if it is intended to support the vicinity of both ends of the screw portion K, it is necessary to support the portion of the rack portion KR. However, it is not appropriate to support (grip) the surface of the rack portion KR with the chuck claws 34L or 34R. When supporting (gripping) with the chuck claws 34L or 34R, it is preferable to support the cylindrical surface of the workpiece W while avoiding the surface of the rack portion KR.
Therefore, as shown in FIG. 1C, a positioning groove WM capable of specifying the rotation angle of the workpiece W is formed on the end surface of the workpiece W (for example, positioning in a direction parallel to the surface of the rack portion KR). A groove WM is formed). The positioning groove WM only needs to be formed on at least one end face.
In the present embodiment, as shown in FIGS. 2A and 2B, the end surface on the rack portion KR side of the workpiece W placed on the temporary support bases 73 and 74 is inserted into the spindle device 30R side. The end surface opposite to the rack portion KR is inserted into the spindle device 30L. Accordingly, since the part of the workpiece W supported by the chuck portion 33L is a cylindrical surface regardless of the position on the circumference, it is preferable to use a chuck portion 33L having three chuck claws 34L (not shown). ). Further, since the part of the workpiece W supported by the chuck claw 33R has the rack part KR on the circumference, the chuck claw 34R is provided with the two claw chuck part 33R so that the cylindrical part can be supported while avoiding this. It is preferable to use (not shown).
When the workpiece W placed on the temporary holders 73 and 74 is held by the chuck portions 33L and 33R, the workpiece W slightly floats from the temporary holders 73 and 74.

Further, as shown in FIGS. 2A and 2B, the hole portion of the spindle portion 32R into which the end surface on which the positioning groove WM is formed is inserted is fitted into the positioning groove WM and moved in the Z-axis direction. A fitting member 35R that is capable of rotating integrally with the spindle portion 32R is provided. The fitting member 35R is biased toward the workpiece W (in the direction of fitting into the positioning groove WM) by an elastic member (not shown), and the elastic member is driven by a control signal from the control means 50 in the spindle portion 32R. It is provided in an adjustment member (not shown) that is movable in the Z-axis direction.
Further, in the hole portion of the spindle portion 32L into which the end surface where the positioning groove WM is not formed is inserted, the contact member 35L with which the end surface of the workpiece W abuts, and the Z of the contact member 35L which is movable in the Z-axis direction. An adjustment member (not shown) for controlling the position in the axial direction is provided.
In the above description, the example in which the positioning groove WM of the workpiece W is formed only on the end surface on the rack portion KR side, but the positioning groove WM may be formed on both end surfaces of the workpiece W. In that case, the contact member 35L in the spindle portion 32L may be the same member as the fitting member 35R.

● [Configuration of thread groove detection device 80 (FIG. 3)]
Next, the configuration of the thread groove detection device 80 will be described with reference to FIG. 3A and 3B are schematic views (plan views) for explaining the configuration, and do not show the appearance of the actual thread groove detecting device 80. FIG. The actual schematic side view of the thread groove detection device 80 is the appearance shown in the example of FIG. 3C, and the detection body moving means 82 is disposed below the holding base 81B.
The thread groove detection device 80 includes at least a contact 83 (corresponding to the measurement element) brought into contact with the measurement target thread groove WN, and a reference line STZ in the lead direction (Z-axis direction) in which the contact 83 is parallel to the workpiece rotation axis CW. Floating means that is held so as to be able to reciprocate from the center, and biasing means that biases the contactor 83 in a radial direction perpendicular to the workpiece rotation axis CW. The reference line STZ will be described later.

Here, as shown in FIG. 3A, the floating means includes two guides 81G for guiding the movement of the holding body 81A holding the contactor 83 in the lead direction, and the holding body 81A substantially at the center of the guide 81G. It is comprised by the elastic members 81BR and 81BL which maintain this. Thereby, the holding body 81A (contactor 83) can reciprocate in the lead direction with respect to the holding base 81B along the guide 81G from the position where the contactor 83 is not in contact with anything. is there.
Further, the urging means is an elastic member 81BB that urges the contactor 83 held so as to be movable in the radial direction (direction orthogonal to the workpiece rotation axis CW) with respect to the holding body 81A. It is configured.
In addition, a spherical member having a diameter that fits within the width of the screw groove WN is fixed to the tip of the contactor 83, and when it enters the screw groove WN, the contact member 83 is guided to the center of the screw groove WN. .

The holding means 81 includes the floating means, the biasing means, the lead side sensors 81SR and 81SL (corresponding to the lead side position detecting means), and the diameter side sensor 81SB (corresponding to the diameter side position detecting means). And.
The lead side sensor is composed of two parts, a first lead side sensor 81SR and a second lead side sensor 81SL. The first lead side sensor 81SR is fixed to the holding base 81B on one side (in this case, the right side) in the lead direction with respect to the contact 83, and the second lead side sensor 81SL is in the lead direction with respect to the contact 83. Is fixed to the holding base 81B on the other side (in this case, the left side).
The first lead side sensor 81SR is, for example, a non-contact sensor, and can detect the distance to the holding body 81A (in this case, the distance in the left direction).
The second lead side sensor 81SL is a non-contact sensor, for example, and can detect the distance to the holding body 81A (in this case, the distance in the right direction).

In the present embodiment, a contactor 83 (holding body 81A) is arranged between two lead-side sensors 81SR and 81SL arranged opposite to each other, and a detection signal from the first lead-side sensor 81SR and the second lead-side sensor Using the ratio of the detection signal from 81SL, it is determined at which position contactor 83 is located between first lead side sensor 81SR and second lead side sensor 81SL.
For example, in the case where the detection signal output increases as the distance increases, the distance from the first lead side sensor 81SR to the measurement target is L1, the detection signal output is m1, and the second lead side sensor 81SL is the measurement target. And the output of the detection signal is m2. In this case, the equation m1: m2 = L1: L2 is established, and L1 + L2 is a predetermined distance. Therefore, using these equations, the distances L1 and L2 can be obtained. In this case, by using the ratio, the error can be canceled even if it deviates in the direction in which m1 and m2 increase or decrease due to temperature drift or the like, so it is smaller than in the case of using one lead-side sensor. The position on the lead side of the contactor 83 can be detected by the error.
In this embodiment, a reference point is provided at an intermediate position in the lead direction of the first lead side sensor 81SR and the second lead side sensor 81SL, and a reference line STZ parallel to the X axis passing through the reference point is set. Yes. The control means 50 recognizes the position of the reference point (X coordinate, Y coordinate, Z coordinate), obtains the distance in the Z-axis direction from the reference line STZ passing through the reference point to the contactor 83, and then determines the screw. Find the position of the groove.

Further, the diameter side sensor 81SB is, for example, a non-contact type sensor, and is fixed to the rear of the holding body 81A and is a distance to the end face of the contactor 83 (in the example of FIG. 3B, a distance Lx in the X-axis direction). ) Can be detected.
The screw groove detecting device 80 shown in the example of FIG. 3 further includes a detecting body moving means 82 (corresponding to a guiding means) capable of moving the holding means 81 in a direction orthogonal to the workpiece rotation axis CW, and a control means (in this case). The control means 50 (refer FIG. 1 (A)) is provided.
In the example shown in FIG. 3, the detection body moving means 82 is composed of a cylinder and a piston 82A, and the holding means 81 is positioned farthest from the workpiece rotation axis CW (position shown in FIG. 3A) or holding means. 81 can be moved to one of the positions closest to the workpiece rotation axis CW (the position shown in FIG. 3B).
The control means 50 recognizes the position of the reference point at the position shown in FIG. 3A and the position shown in FIG. 3B, and also recognizes the length of the contact 83 in the X-axis direction. . Therefore, by obtaining the distance Lx from the diameter side sensor 81SB to the end face of the contactor 83, the position in the X-axis direction at the tip of the contactor 83 can be recognized, and the position of the tip of the contactor 83 in the X-axis direction. Based on the above, it is possible to determine whether or not the contactor 83 has entered the thread groove WN. For example, it is assumed that the determination threshold is set to Δx, and the theoretical value of the distance Lx when entering the screw groove is the distance K1. In this case, the control means 50 determines that the contactor 83 has entered the thread groove WN when the measured distance is within the distance K1 ± Δx.
With the above configuration, the thread groove detection device 80 can be accommodated in a compact manner, and can be easily mounted on the machine tool 1 as shown in FIGS. 1 (A) and 1 (B).

As shown in FIG. 3C, the contact 83 of the screw groove detection device 80 described above is moved along the guide direction AN so as to be orthogonal to the workpiece rotation axis CW. It is necessary to adjust so that the guide direction AN coincides with the direction orthogonal to CW.
As shown in FIG. 3C, the thread groove detecting device 80 includes adjusting means 84F and 84R that can finely adjust the direction of the guide direction AN. Hereinafter, the guide direction AN is orthogonal to the workpiece rotation axis CW. An adjustment method and the like for adjustment will be described in order.

● [Adjustment method for adjusting the guide direction AN to be orthogonal to the workpiece rotation axis CW (FIG. 4)]
In the following description, a method for adjusting the guide direction AN of the contactor 83 so as to coincide with the direction orthogonal to the workpiece rotation axis CW using the master workpiece MW shown in FIG. explain.
The master work MW shown in FIG. 4A has at least a plurality of cylindrical portions Tn (T1 to T3 in the example of FIG. 4A) on the concentric axis ZM1, and the cylindrical surfaces of the respective cylindrical portions have concentric axes. Reference grooves Mn (M1 to M3 in the example of FIG. 4A) are formed in a direction parallel to ZM1. Each reference groove Mn is formed so as to be positioned on one plane HM passing through the concentric axis ZM1.
The width and depth of the reference groove are, for example, about several μm to several tens of μm, and are set to a size that allows the tip of the contactor 83 to enter.
Therefore, as shown in FIG. 4B, when the master work MW is viewed from a direction parallel to the concentric axis ZM1, each reference groove Mn (in this case, M1 to M3) is on a straight line passing through the concentric axis ZM1. Are lined up.
Next, the adjustment procedure will be described with reference to FIG. In addition, description of this adjustment procedure demonstrates the machine tool 1 shown to FIG. 1 (A) and (B) as an example.
Hereinafter, an adjustment method for adjusting the actual guide direction AN (real) of the contactor 83 to an ideal guide direction AN (type) orthogonal to the workpiece rotation axis CW will be described with reference to FIG.

First, the master work MW is held so that the work rotation axis CW and the concentric axis ZM1 coincide. In the machine tool 1 shown in FIG. 1, the master work MW is supported by the spindle devices 30L and 30R.
Next, the master work MW and the contact 83 are relatively moved in a direction parallel to the work rotation axis CW so that the reference groove M1 (cylindrical portion T1) of the master work MW and the contact 83 are opposed to each other. In the case of the machine tool 1 of FIG. 1, the master work MW is moved along the Z-axis direction by the spindle devices 30L and 30R.
Next, when the contactor 83 is advanced along the guide direction AN (real) and the contactor 83 comes into contact with the cylindrical portion T1 of the master work MW, the tip of the contactor 83 comes into contact with (enters) the reference groove M1. Then, the master work MW is rotated about the work rotation axis CW, and the rotation angle θm1 of the master work MW when it hits (enters) the reference groove M1 is obtained.

Next, the master work MW and the contact 83 are relatively moved in a direction parallel to the work rotation axis CW so that the reference groove M2 (cylindrical portion T2) of the master work MW and the contact 83 face each other.
Then, when the contactor 83 is advanced along the guide direction AN (real) and the contactor 83 comes into contact with the cylindrical portion T2 of the master work MW, the tip of the contactor 83 comes into contact with (enters) the reference groove M2. The master workpiece MW is rotated about the workpiece rotation axis CW, and the rotation angle θm2 of the master workpiece MW when it hits (enters) the reference groove M2 is obtained.
Similarly, a rotation angle θm3 is obtained by rotating the master work MW so that the tip of the contactor 83 abuts (enters) the reference groove M3.

Respective rotation angles with which contactor 83 hits (enters) with respect to at least two or more reference grooves are obtained, and from this angle and the diameter of each cylindrical portion, how much guide direction AN (real) is in which direction and how much It is possible to calculate whether or not there is a deviation.
The thread groove detection device 80 includes adjustment means 84F and 84R between the support body 84, and the operator can adjust the fine adjustment means 84F and 84R according to the calculated deviation in the guide direction AN (real). adjust. Then, the operator adjusts until the rotation angle θm1 for the reference groove M1, the rotation angle θm2 for the reference groove M2, and the rotation angle θm3 for the reference groove M3 coincide. Thereby, the guide direction AN can be adjusted more accurately and more easily in the direction orthogonal to the workpiece rotation axis CW.

● [Method for detecting angle between guide direction AN and reference plane STM (FIGS. 5 and 6)]
In the following description, a method for detecting the angle between the guide direction AN of the contactor 83 and the predetermined reference surface STM (so-called reference extraction method) will be described using the master work MW shown in FIG. In the present embodiment, the predetermined reference plane STM is set to a plane that includes the workpiece rotation axis CW and is parallel to the X axis and the Z axis that are the movement axes of the grindstone 22 (processing tool).
The master work MW shown in FIG. 5A has a cylindrical portion T4 at least in part, and a planar portion SM parallel to the axis ZM2 of the cylindrical portion T4 is formed in a part of the cylindrical portion T4, and the cylindrical portion T4. A reference groove M4 parallel to the axis ZM2 is formed on the cylindrical surface. In the master work MW shown in FIG. 4A, the reference groove M4 is formed on a plane HM that includes the axis ZM2 and is parallel to the plane portion SM.
The master work MW shown in FIG. 5A is an example of a master work MW having a good weight balance in which two plane portions SM are formed so as to face each other with the axis ZM2 interposed therebetween. May be formed only on one side.

Next, a procedure for detecting the angle θ between the guide direction AN and the reference plane STM will be described with reference to FIGS. In addition, description of this detection procedure demonstrates the machine tool 1 shown to FIG. 1 (A) and (B) as an example.
When the machine tool 1 shown in FIGS. 1A and 1B is used, for example, when the position of the thread groove of the workpiece W in the Z-axis direction is measured by the contact 83 of the thread groove detecting device 80, for example, FIG. As shown in (B), the position of the thread groove measured by the contactor 83 is shifted in the Z-axis direction by an amount corresponding to the angle θ with respect to the position of the contact point between the grindstone 22 and the workpiece W (processing point). Yes. When the thread groove pitch is PM, correction of PM * θ (degrees) / 360 (degrees) is necessary. Further, the angle θ between the reference surface STM and the guide direction AN greatly affects the accuracy of the screw groove position.
Therefore, in the following, a more accurate detection method of this angle θ will be described.

First, the master work MW is held so that the work rotation axis CW and the axis ZM2 of the cylindrical portion T4 coincide. In the machine tool 1 shown in FIG. 1, the master work MW is supported by the spindle devices 30L and 30R.
Next, the master work MW and the contact 83 are relatively moved in a direction parallel to the work rotation axis CW so that the cylindrical portion T4 of the master work MW and the contact 83 face each other. In the case of the machine tool 1 of FIG. 1, the master work MW is moved along the Z-axis direction by the spindle devices 30L and 30R.
Next, the rotation angle of the master work MW is adjusted so that the plane portion SM of the master work MW and the preset reference plane STM are parallel to obtain an initial angle. For example, as shown in FIG. 5B, a micrometer 90 or the like is attached to a grindstone table 20 that is movable in a plane parallel to the reference surface STM, and a micrometer tip 90A is disposed on the flat surface SM. The position of the planar portion SM in the Y-axis direction is measured while moving 20 in the X-axis direction and the Z-axis direction, and the rotation angle of the master work MW is adjusted so that the measured value becomes constant. In the example of FIG. 5C, the reference groove M4 is on the reference surface STM.

Next, the contactor 83 is moved along the guide direction AN, the contactor 83 is brought into contact with the cylindrical portion T4, and the master work MW is rotated around the work rotation axis CW so that the contactor 83 hits (enters) the reference groove M4. The rotation angle β (rotation angle from the initial angle) of the master work MW when it contacts (enters) the reference groove M4 is obtained.
As shown in FIG. 5C, the angle θ formed by the guide direction AN and the reference surface STM in this case can be obtained as 180−β (degrees).
Thus, the angle between the guide direction AN and the reference plane STM can be detected more accurately and more easily.

In the example of FIGS. 5A to 5C, when an angle α (arrangement angle α) formed by a perpendicular drawn from the axis ZM2 to the plane portion SM and a perpendicular drawn from the axis ZM2 to the reference groove M4 is 90 degrees. However, an example in which this angle is not 90 degrees will be described next.
When the position of the reference groove M4 is the position shown in FIG. 6A, the angle formed by the perpendicular line extending from the axis ZM2 to the plane portion SM and the perpendicular line extending from the axis ZM2 to the reference groove M4 is the arrangement angle α ′ ( α ′ ≠ 90 degrees).
In the same manner as described above, after the plane portion SM is parallel to the reference surface STM and the initial angle is obtained, the master workpiece MW is rotated around the workpiece rotation axis CW so that the contactor 83 contacts (enters) the reference groove M4. The rotation angle β ′ (rotation angle from the initial angle) of the master work MW is obtained.
In this case, as can be seen from FIG. 6 (A) before the rotation and FIG. 6 (B) after the rotation, the angle θ formed by the guide direction AN and the reference plane STM is 180−β ′ + ( α′−90) (degrees).

  Moreover, the master work MW illustrated in FIG. 6C is an example of the master work MW in which the master work MW illustrated in FIG. 4A and the master work MW illustrated in FIG. . By using this master work MW, it is possible to adjust the guide direction AN of the contactor 83 and detect the angle between the adjusted guide direction AN and the reference plane STM. If the master work MW shown in FIG. 6 (C) is used, the adjustment of the guide direction AN and the angle detection between the guide direction AN and the reference plane STM can be performed. The accuracy of adjustment and detection can be further improved.

● [Example of application to machine tool 1 equipped with thread groove detection device 80]
As described above, the thread groove detection device 80 that adjusts the guide direction AN of the contactor 83 to be accurately orthogonal to the workpiece rotation axis CW and accurately detects the angle between the guide direction AN and the reference plane STM is provided. A procedure for detecting the position in the Z-axis direction of the thread groove WN formed on a part of the cylindrical surface of the workpiece W will be described.
As shown in FIG. 3A, the control means 50 outputs a drive signal to the detection body moving means 82 from a position where the holding means 81 is farthest from the work rotation axis CW, and directs the holding means 81 toward the work rotation axis CW. Advance (toward the thread groove of the workpiece W).
Then, the control unit 50 moves the holding unit 81 to a position closest to the workpiece rotation axis CW to bring the contactor 83 into contact with the threaded portion K of the workpiece W. Here, the control means 50 recognizes the distance Lx to the end surface of the contactor 83 to be detected by the radial sensor 81SB when the contactor 83 enters the screw groove WN. Then, the control means 50 determines that the distance obtained based on the detection signal from the radial sensor 81SB is a value in the vicinity of the distance K1 (theoretical value when entering the screw groove) (for example, the determination threshold is Δx). In the case where the obtained distance is within the distance K1 ± Δx), it is determined that the contactor 83 has entered the screw groove WN, and is not a value near the distance K1, but a value smaller than the distance K1-Δx. It is determined that the contactor 83 is not in the thread groove WN.

When the holding means 81 is brought close to the workpiece rotation axis CW and the contactor 83 is brought into contact with the screw groove WN, the contactor 83 moves in the lead direction if there is a screw groove WN at the tip of the contactor 83. do not do. However, there are more cases where there is a shift than when there is a screw groove WN at the destination. The example of FIG. 3B shows a case where the position in the lead direction of the screw groove WN is shifted by −Δz with respect to the reference line STZ. The control means 50 can determine the distance (−Δz) of the contactor 83 from the reference line STZ based on detection signals from the lead side sensors 81SR and 81SL.
The control means 50 is the position of the reference point of the holding means 81 on the machine tool 1 (the position of the reference point (X coordinate, Y coordinate, Z coordinate) in the state of FIG. 3B closest to the workpiece rotation axis CW). Recognize. Then, the control means 50 determines the position of the contact 83 from the position of the holding means 81 on the machine tool 1 in the Z-axis direction, the distance (−Δz) in the Z-axis direction from the reference line STZ (reference point) with respect to the holding means 81. The position in the Z-axis direction on the machine tool 1 of the thread groove WN with which the tip is in contact can be obtained.
When the control means 50 determines that the contactor 83 is not in the thread groove WN, it outputs a control signal to the spindle devices 30L and 30R, and rotates the workpiece W at least once around the workpiece rotation axis CW. The contact 83 may go into the thread groove WN.

  As described above, the thread groove detection device 80 described in the present embodiment directly detects the position of the center of the thread groove WN by bringing the contactor 83 into contact therewith, so that the position of the thread groove WN in the lead direction is measured. High accuracy. In addition, the position of the center of the screw groove can be measured in a very short time compared to the conventional detection method in which the boundary between the screw groove and the shoulder is reciprocated many times. Furthermore, since the thread groove detection device 80 can be configured compactly, it can be easily mounted on the machine tool 1.

Using the screw groove detection device 80 described above, the position of the screw groove WN in the lead direction is measured, and the workpiece W is rotated by a predetermined angle by the spindle devices 30R and 30L, so that the screw groove detection device 80 Then, the moving distance of the contact 83 in the lead direction during the rotation at the predetermined angle is measured to obtain the pitch PM of the thread groove WN. Then, the position in the Z-axis direction of the obtained screw groove WN is corrected using the pitch PM and the angle θ, and the position in the Z-axis direction of the screw groove at the machining location by the grindstone 22 is obtained.
Furthermore, the Z-axis direction drive motor 10M is controlled so that the grindstone 22 (processing tool) is positioned at the position in the Z-axis direction of the obtained screw groove WN, and the X-axis direction drive is performed so that the grindstone 22 enters the screw groove WN. The motor 20M is controlled.
And while rotating the workpiece | work W using the spindle apparatus 30R and 30L, based on the measured pitch, the grindstone 22 is moved to a lead direction using the Z-axis direction drive motor 10M, and the thread groove WN is finish-ground. .
In the description of the present embodiment, the grindstone 22 is moved in the X-axis direction with respect to the workpiece W. However, the workpiece W may be moved in the X-axis direction with respect to the grindstone 22. Therefore, the grindstone 22 moves relative to the workpiece W in the X-axis direction.
Similarly, with respect to the Z-axis direction, the grindstone 22 is moved in the Z-axis direction with respect to the workpiece W. However, the workpiece W may be moved in the Z-axis direction with respect to the grindstone 22. Therefore, the grindstone 22 moves relative to the workpiece W in the Z-axis direction.

The machine tool 1 provided with the method for adjusting a probe according to the present invention, the method for detecting the angle of the probe, the method for correcting the detection result by the probe, and the thread groove detection device 80 includes the procedure, processing, The present invention is not limited to the appearance, configuration, structure, and the like, and various changes, additions, and deletions are possible without departing from the scope of the present invention. For example, instead of a structure in which both ends of the workpiece W are held by a chuck, a structure in which the center of one or both ends is supported may be used, and a tool or the like may be used instead of the grindstone 22 as a processing tool. Good.
In the description of the present embodiment, the example in which the contact 83 slides in the radial direction orthogonal to the workpiece rotation axis CW has been described. However, the contactor 83 is configured to slide in a direction intersecting the workpiece rotation axis CW at a predetermined angle. (The direction in which the contact is biased may also be biased in a direction intersecting the workpiece rotation axis CW). Further, the example in which the guiding means (detecting body moving means 82) guides the contact in the direction orthogonal to the workpiece rotation axis CW has been described, but the guide is configured to guide in a direction intersecting the workpiece rotation axis CW at a predetermined angle. May be.
The numerical values used in the description of the present embodiment are examples, and are not limited to these numerical values.
The machine tool 1 provided with the thread groove detection device 80 described in the present embodiment is not limited to a grinding machine, and can be applied to a machine using a center work such as a lathe. Further, the present invention can be applied to a method of measuring a diameter with a single probe and a machine tool, and for example, can be applied to a displacement probe of a machine tool that measures a cam meter.

It is a figure explaining one embodiment of machine tool 1 provided with screw slot detecting device 80 of the present invention, and a figure explaining an example of work W. It is a figure explaining a mode that the workpiece | work W is supported using the spindle apparatuses 30L and 30R. It is a figure explaining the structure and operation | movement of the thread groove detection apparatus. It is a figure explaining the external appearance of the master workpiece MW for adjusting the guide direction AN of the measuring element (contact 83) to be orthogonal to the workpiece rotation axis CW, and the adjusting method. It is a figure explaining the external appearance of the master work MW for detecting the angle of the guide direction AN of the measuring element (contact 83) and the reference plane STM, and an angle detection method. It is a figure which shows the example of the master work MW which put together the other example of the angle detection method, and the master work MW shown in FIG. 4 (A), and the master work MW shown in FIG. 5 (A).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Base 10 Grinding wheel base 10M Z-axis direction drive motor 30LM, 30RM Z-axis direction drive motor 10E, 30LE, 30RE Detection means 20 Grinding wheel table 20M X-axis direction drive motor 20E Detection means 21 Grinding wheel drive motor 22 Grinding wheel (processing) tool)
30L, 30R Spindle device 50 Control means 60 Truing device 80 Thread groove detection device 81 Holding means 81A Holding body (floating means)
81BR, 81BL Elastic member (floating means)
81G guide (floating means)
81SR First lead side sensor (first lead side position detecting means)
81SL Second lead side sensor (second lead side position detecting means)
81SB Diameter side sensor (Diameter side position detection means)
81B holding base 81BB elastic member (biasing means)
82 Detection body moving means (guide means)
83 Contact (Measuring element)
84F, 84G Adjustment means AN Guiding direction MW Master work T1 to T4 Cylindrical part M1 to M4 Reference groove SM Plane part STM Reference surface STZ Reference line CW Workpiece rotation axis W Workpiece
WN thread groove K thread

Claims (4)

A method of adjusting a measuring element, wherein a measuring element is brought into contact with the cylindrical part from a direction intersecting the rotating axis with respect to a workpiece having a cylindrical part at least partially held rotatably around a predetermined rotation axis,
The measuring element is attached to a guide means capable of moving back and forth in a guide direction that substantially intersects the rotation axis and allows fine adjustment of the direction,
A cylindrical portion having at least a plurality of different diameters is provided on a concentric axis, and the cylindrical surface of each cylindrical portion is formed in a direction parallel to the concentric axis and is located on a single plane passing through the concentric axis. A master work having a reference groove formed as described above is held around the rotation axis so that the rotation axis and the concentric axis coincide with each other,
Set the rotation angle of the master work so that the measuring element and the reference groove face each other,
After moving the measuring element relative to the master work in a direction parallel to the rotation axis so that the reference groove of the cylindrical portion selected from the master work and the measuring element face each other. The rotation angle of the master work adjusted so that the measuring element hits the reference groove by moving the measuring element toward the reference groove using the guide means is a reference of at least two cylindrical portions. Seeking for the groove,
Adjusting the guide direction of the guide means so that the probe contacts the reference groove of at least two cylindrical portions at the same rotation angle in the master work;
How to adjust the probe. Measurement in which a workpiece having a cylindrical portion at least partially held rotatably around a predetermined rotation axis is attached to guide means capable of moving back and forth in a guide direction intersecting the rotation axis and brought into contact with the cylindrical portion. A child angle detection method,
At least a part of the cylindrical part has a cylindrical part, and a part of the cylindrical part is formed with a flat part parallel to the axis of the cylindrical part, and the cylindrical surface of the cylindrical part has a reference groove parallel to the axis of the cylindrical part Is held around the rotation axis so that the axis of rotation and the axis of the cylindrical portion coincide with each other,
As an arrangement angle, an angle formed by a perpendicular line dropped from the axis of the cylindrical part to the flat part and a perpendicular line dropped from the axis of the cylindrical part to the reference groove,
By adjusting the rotation angle of the master work as an initial angle so that the reference plane set in advance to be parallel to the rotation axis and the plane portion of the master work are parallel,
Based on the rotation angle from the initial angle in the master work adjusted so that the probe touches the reference groove when the probe is moved in the guide direction, and the arrangement angle, with respect to the reference surface Detecting an angle of the guide direction;
How to detect the angle of the probe. At least a plurality of cylindrical portions having different diameters are provided on a concentric axis, and the cylindrical surface of each cylindrical portion is formed in a direction parallel to the concentric axis and is located on the same plane passing through the concentric axis. A master work having a reference groove formed and having a plane part parallel to the concentric axis formed in a part of at least one of the cylindrical parts,
As an arrangement angle, an angle formed by a perpendicular line dropped from the concentric axis to the plane portion and a perpendicular line dropped from the concentric axis to the reference groove,
After adjusting the guide direction of the guide means using the method for adjusting a probe according to claim 1, the position relative to the reference plane detected using the method for detecting the angle of the probe according to claim 2. Correcting the detection result detected using the probe based on the angle of the guide direction;
A method for correcting the detection result using a probe. A machine tool including a thread groove detection device that detects a position of a thread groove formed on at least a part of a cylindrical surface of a work that is rotatably held around a predetermined rotation axis,
A probe to be brought into contact with the thread groove;
Floating means for holding the probe so that it can reciprocate in a lead direction parallel to the rotation axis;
An urging means for urging the measuring element in the guide direction intersecting the rotation axis;
Lead-side position detecting means capable of detecting the position in the lead direction of the probe;
A radial position detection means capable of detecting the position of the guide in the guide direction;
Guiding means capable of moving the measuring element forward and backward in a guiding direction substantially intersecting the rotation axis and finely adjusting the guiding direction;
A working tool for grinding the thread groove,
After adjusting the guide direction of the guide means using the method for adjusting a probe according to claim 1,
Press the measuring element against the thread groove of the workpiece so as to intersect the rotation axis,
Detecting that the probe has entered the screw groove using the radial side position detecting means,
Detecting the position of the lead direction in the probe using the lead side position detection means, detecting the position of the screw groove,
Further, the position of the probe in the lead direction after the workpiece is rotated by a predetermined angle is detected, and the pitch of the screw groove is obtained based on the amount of movement of the probe in the lead direction with respect to the predetermined angle. ,
The detected position of the screw groove is corrected based on the angle of the guide direction with respect to the reference surface detected using the angle detection method of the stylus according to claim 2 and the obtained pitch of the screw groove. ,
Grinding the thread groove by positioning a working tool that can move relative to the workpiece in a direction parallel to the reference plane at the position of the corrected thread groove,
A machine tool equipped with a thread groove detection device.

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