Patent ID: 12210332

Embodiments of the present invention will be explained with reference to the accompanying drawings.

First Embodiment

A balance and runout adjustment system is used in adjusting a mass balance and a runout amount of a rotary tool including a cutting tool used in e.g. a mirror finishing of a precision mold. As shown inFIG.1, the balance and runout adjustment system100includes a rotary tool11having a tool5and an imaging device20. In this embodiment, with use of the imaging device20, a mass balance and a runout amount of the rotary tool11are determined. The imaging device20consists essentially of an imaging section21and a controller22. The imaging section21is to be installed on a machine tool1of a computerized numerical control (CNC) type having a rotary tool11attached thereto.

As shown inFIGS.1through4, the rotary tool11is constituted by attaching the tool5to a tool holder10which is to be mounted on a spindle2of the machine tool1. In the spindle2, at an upper portion thereof, there is provided a first mark3used as a reference point of rotation phase and at a portion adjacent to the tool holder10, there is provided a second mark4. In the tool holder10, at a portion thereof adjacent the spindle2, a third mark13is provided and at a portion thereof adjacent the tool5, a fourth mark14is provided. In the spindle2, the first mark3and the second mark4are provided at a same position with respect to the circumferential direction. Further, in the tool holder10, the third mark13and the fourth mark14are provided at a same position with respect to the circumferential direction. In this way the first mark3and the second mark4and also the third mark13and the fourth mark14are arranged respectively along a rotational axis Z of the spindle2.

As shown inFIG.2, the tool holder10is attached to the spindle2, in such a manner that the second mark4and the third mark13are aligned in position with each other.

[Tool Holder]

As shown inFIGS.4through6, the tool holder10includes a shank portion15provided on one end side in the rotational axis Z direction (seeFIG.2) and configured to be attached to the spindle2of the machine tool1, a chuck portion17provided on the other end side in the rotational axis Z direction and configured to allow attachment of the tool5thereto and a flange-like portion19(an example of an “intermediate portion”) between the shank portion15and the chuck portion17. The shank portion15and the chuck portion17are formed with tapering toward the respective leading ends thereof. To the chuck portion17of the tool holder10, the tool5will be attached via e.g. a shrink fit, a collet chuck, etc. Alternatively the tool5can be attached as an “insert tip” to the tool holder10.

In the flange-like portion19, at an end face19athereof on the side of the chuck portion17and on a same circumference centering about the axis of the tool holder10, there are provided 12 (twelve) screw holes18(an example of “insertion holes”) with 30-degrees angular spacing therebetween. Each screw hole18is slanted to be closer to the axis as it extends toward the shank portion15side. The diameters and the depths of these twelve screw holes18are all the same. Each screw hole18includes a first hole portion18awhich is cylindrical and into which a screw member41will be inserted and assembled, and a second hole portion18bwhich is tapered and formed continuously with the deep side of the first hole portion18a. In the screw hole18, into the second hole portion18bthereof, a ball body41is inserted and the screw member41(an example of an “insertion member”) is assembled in the first hole portion18a, with the screw member41being placed in contact with the ball body40. In order to prevent the screw member41from protruding from the end face19a, a sum of the axial length of the ball body40and an axial length of the screw member41is set shorter than the depth of the screw hole18. Further, a female screw portion of the first hole portion18ais set with a sufficient length that allows clamping of the screw member41even after establishment of contact between this screw member41and the ball body40.

The screw member41, as shown inFIG.6, is provided in the form of a “set screw”, and a plurality of kinds of such screw members41are prepared with slightly different masses, namely, different lengths, from each other. Alternatively the plurality of screw members41may be formed of different kinds of materials having different densities, with a same length, thus rendering the masses thereof different from each other.

In the plurality of screw holes18of the tool holder10, screw members41ahaving a predetermined mass are screwed in advance. Under this condition, a test is conducted on the rotary tool11by a balancing machine. Then, based on its result, it is possible to adjust the dynamic mass balance at the time of rotation of the rotary tool11.

In case it is found as the result of the test on the rotary tool11by the balancing machine that imbalance exists in the mass of the rotary tool11, this imbalance will appear as runout of the rotary tool11in the radial direction. As a result, the balancing machine will show an angle of the unbalanced portion from a reference point in the rotation phase and a mass of adjustment diameter relative to the rotational axis Z. Then, in order to render the maximum runout amount of the rotary tool11as close as possible to zero, in place of the screw member41ahaving the predetermined mass, a screw member41having a mass different therefrom will be threaded (screwed) in the screw hole18. In this way, the dynamic mass balance at the time of rotation of the rotary tool11is adjusted.

[Imaging Device]

As shown inFIG.1, the imaging device20consists essentially of an imaging section21and a controller22(an example of a “calculating section”). The imaging section21includes a beam (optical beam or light) projecting portion23for emitting an irradiation beam (light) toward the tool5, an image sensor24configured to receive the irradiation beam for imaging the tool5, and an objective lens25and an imaging lens26which form an image of the tool5as an imaging target on the beam receiving face of the image sensor24. The beam projecting section23is constituted of e.g. a light emitting diode (LED), etc. The imaging sensor24is configured to receive the irradiation beam via a mirror27. The imaging section21includes a control board as a controlling section28for executing imaging operations by the image sensor24by a predetermined time interval. The controlling section28includes a trigger circuit29for executing the imaging operations.

The controller22is configured to be capable of effecting processing of data such as captured images of the machine tool1and the imaging device20as well as inputting operations of various kinds of data such as the number of blade portions5A (blade number) included in the tool5, a rotational speed for imaging to be described later, etc. A phase detecting section31includes a photoelectric sensor for detecting the first mark3provided on the spindle2and is used for detecting the reference point (the portion having zero rotational angle) of the rotation phase of the spindle2. Upon detection of the first mark3by the phase detecting section31, a detection signal will be transmitted from the phase detecting section31to the controlling section28.

In the balance and runout adjustment system100, the balance and runout of the rotary tool11are adjusted by following steps.

The imaging section21of the imaging device20will be mounted to the machine tool1. The tool holder10(rotary tool11) comprised of the tool5having the plurality of blade portions5A will be mounted on a spindle2of the machine tool1. In doing this, the position of the reference point (first mark3, second mark4) of the spindle2of the machine tool1will be brought into alignment with the position of a tool reference point (third mark13) of the tool holder10.

In succession, with using the balance determining device (the imaging device20in the case of the instant embodiment), the mass balance of the rotary tool11in the course of its rotation is determined (balance determining step). Thereafter, based on the mass balance of the rotary tool11determined by the balance determining device, balance adjustment will be effected on the tool holder10(rotary tool11) with this tool holder10being kept attached to the spindle2of the machine tool1(balance adjusting step).

Next, with using the runout determining device (the imaging device20in the case of the instant embodiment), a runout amount of the tool5(rotary tool11) at the time of rotation is determined (runout determining step). Thereafter, based on the runout amount determined by the runout determining device, runout adjustment is effected on the tool holder10(rotary tool11) with this tool holder10being kept attached to the spindle2of the machine tool1(runout adjusting step).

With the above-described configuration, at the time of or in the course of rotation of the rotary tool11, the mass balance of the rotary tool11can be determined with using the imaging device20and also the runout amount of the tool5(blade portions5A) included in the rotary tool11can be determined. Thus, the mass balance and the runout amount of the rotary tool11can be easily determined. Moreover, since the adjustments of the mass balance and the runout amount of the rotary tool11are effected via the tool holder10as being kept attached to the spindle2of the machine tool1, these adjustments of the mass balance and the runout amount of the rotary tool11based on the determined results can be effected easily and with high precision.

Next, the specific contents of the balance determining step, the balance adjusting step, the runout determining step and the runout adjusting step will be explained.

(Balance Determining Step and Balance Adjusting Step)

In the instant embodiment, the balance determining step is effected with using the imaging device20. Specifically the imaging sensor24images (i.e. picks up an image of) the rotary tool11and then based on the obtained image of the rotary tool11, “outer circumferential position data” (runout amount in the radial direction) of the rotary tool11will be acquired and with using the controller22(calculating section), mass balance of the rotary tool11will be determined from the resultant outer circumferential position data. The irradiation beam from the beam projecting section23will be caused to be irradiated on the rotary tool11by either elevating the imaging device20or lowering the spindle2together with the phase detecting section31.

More particularly the irradiation beam from the beam projecting section23will be irradiated onto the cylindrical portion (e.g. the chuck portion17) of the tool holder10at the time of rotation, and then based on runout of this cylindrical portion, the mass balance of the rotary tool11will be determined. This determination of runout of the rotary tool11by the imaging device20is effected by either a dividing imaging (dividing shooting) method or a delayed imaging (delayed shooting) method. The dividing imaging method is the imaging method to be employed at the time of low speed rotation and the delayed imaging method is the imaging method to be employed at the time of high speed rotation. The dividing imaging method and the delayed imaging method will be described in details in the following description of the runout determining step.

With using the imaging device20, runout amounts per predetermined rotational angle in one whole circumference of the cylindrical portion (chuck portion17) of the rotary tool11are determined.FIG.7shows an example of determination result. From this illustration, it is understood that the runout amount becomes the maximum of 16 μm when the rotational angle is 160 degrees and becomes the minimum of 4 μm when the rotational angle is 340 degrees.FIG.8shows the result ofFIG.7mapped on an X-Y coordinate system. Specifically the minimum runout amount (340 degrees, 4 μm) was set as a predetermined position in the positive direction on the X axis from the origin of the X-Y coordinate system. Then, based on this position as the reference, the runout amounts of all angles were mapped on the X-Y coordinate system. The distance from the origin of the X-Y coordinate system to each point represents the runout amount. InFIG.8, the positive direction of the X axis on the X-Y coordinate system was set as the reference point (0 degree) of the rotation phase of the rotary tool11. InFIG.8, the center position of the runout displacements of the circumferential portions of the rotary tool11are shown as Z1.

Next, the runout amounts of the respective rotational angles were re-calculated with aligning the minimum value of the runout amount (340 degrees, 4 μm) with the origin of the X-Y coordinate system. Specifically, each point constituting the circle shown inFIG.8was shifted by 4.0 μm to the negative direction side of the X axis. The re-calculated runout amount of each rotational angle can be mapped in the graph shown inFIG.9. As shown in thisFIG.9, the center position of runout displacements of the rotary tool11is moved from Z1to Z2. The coordinates of Z2can be calculated by averaging X values and Y values respectively of the runout amounts of angles different by 180 degrees in the rotation phase. In the example shown inFIG.9, the position Z2is a position having a counterclockwise angle θ1 of 160 degrees relative to the origin of the X-Y coordinate system as the center, on the premise of a positive portion of the X axis extending from the origin of the X-Y coordinate system being the reference line (to be referred to as “reference line S” hereinafter) with 0 degree angle relative to the origin of the X-Y coordinate system. Further, the magnitude of the vector from the origin of the X-Y coordinate system to the position Z2is 10 μm. The angle θ1 representing the direction of this vector is the rotational angle where the runout amounts shown inFIG.7become the maximum and the minimum and its magnitude is the average of the maximum and minimum values of the runout amounts at that angle. Hereinafter, this vector will be referred to as vector V1.

Here, for the rotary tool11having the position Z2as its rotational center, influence to its mass balance given by a “trial weight” will be obtained by adding a trial weight to the tool holder10. Specifically, as illustrated inFIG.10, of the screw holes18distributed at 12 (twelve) positions in the circumferential direction of the tool holder10, from a screw hole18at one position (e.g. No. 0, 0 degree), the standard screw member41awill be pulled out and instead a screw member41bwith a trial weight (e.g. 200 mg) added to the mass of the screw member41awill be assembled therein. Thereafter, the rotary tool11will be rotated at the same rotational speed and change occurring in runout of the rotary tool11will be determined.

Suppose the addition of the trial weight resulted in shifting from Z2to Z3in the center position of runout displacements of the tool holder (seeFIG.11). The position Z3is the position having a counterclockwise angle θ2 of 200 degrees from the reference line S. Let us suppose also that the magnitude of the vector from the origin of the X-Y coordinate system to the position Z3is 6.5 μm, which is reduced from the magnitude of 10 μm of the vector from the origin of the X-Y coordinate system to the position Z2. Hereinafter, this vector will be referred to as the vector V2.

The influences of trial weights that result in shifting of the runout center position of the rotary tool11are shown inFIG.12. Runout generated by a trial weight can be obtained as vector V3by vector calculation based on the vector V1and the vector V2. As the sum of the vector V1and the vector V3is the vector V2, the vector V3can be obtained by subtracting the vector V1from the vector V2.

In the vector V3indicative of the influence of trial weight, an X component V3xcan be represented by Formula 1 below.

[Formula⁢1]V⁢3⁢x=V⁢2⁢cos⁢θ⁢2-V⁢1⁢cos⁢θ⁢1=3.29

Also, the y component V3ycan be represented by Formula 2 below.

[Formula⁢2]V⁢3⁢y=V⁢2⁢sin⁢θ⁢2-V⁢1⁢sin⁢θ⁢1=-5.64

From the above, a clockwise angle θ3 from the reference line S to the vector V3and the magnitude of the vector V3can be calculated respectively by Formula 3 and Formula 4 below.

[Formula⁢3]θ⁢3=tan-1(V⁢3⁢y/V⁢3⁢x)[Formula⁢4]V⁢3=(V⁢3⁢x)2+(V⁢3⁢y)2

In the example shown inFIG.12, the angle θ3 is −59.8 degrees and the magnitude of the vector V3is 6.5 μm.

FIG.13shows the position of the trial weight C, the position of an offset load D and a position (correction position) E for correcting the unbalanced (eccentric) load of the rotary tool11by addition of the offset load D. From the relationship between the vector V3indicative of the influence of the trial weight C and the position of the trial weight C (No. 0, 0 degree), the unbalanced load D of the rotary tool11is calculated by Formula 5 below. Here, the unbalanced load D is defined as a load of such magnitude that generates imbalance in the rotary tool11in the course of its rotation.

[Formula⁢5]unbalanced⁢load⁢D=((magnitude⁢of⁢vector⁢V⁢1/magnitude⁢of⁢vector⁢V⁢3)×mass⁢of⁢trial⁢weight)=30.8mg.

In the circumferential direction of the rotary tool11, the position of the unbalanced load D is the position having an angle θ4 from the reference line S and the angle θ4 is calculated by Formula 6 below

[Formula⁢6]θ⁢4=(angle⁢⁢θ⁢1⁢of⁢vector⁢V⁢1-angle⁢⁢θ⁢3⁢of⁢vector⁢V⁢3)=219.8degrees

The unbalanced load D shown inFIG.13is the position where the unbalanced load D exists in the rotary tool11. Therefore, by removing the unbalanced load D from the tool holder10for example, the runout amount of the rotary tool11becomes minimum. In place of this, in case the unbalanced load D is to be offset by addition of a balance correction weight to the tool holder10, the weight will be added to the position E shown inFIG.13. This position E is the position having an angle θ5 from the reference line S which is at the position in symmetry with the angle θ4 relative to the origin; and the angle θ5 is calculated by the following Formula 7 below.

[Formula⁢7]θ⁢5=θ⁢4-180⁢degrees

In the case of the example shown inFIGS.7through12, inFIG.13, the unbalanced load D is 308 mg and the angle θ4 from the reference line S to the position of the unbalanced load D is 219.8 degrees. Therefore, the angle θ5 from the reference line S to the position E becomes 39.8 degrees. The screw holes18are provided with 30 degree angular spacing therebetween in the circumferential direction of the tool holder10. Therefore, by addition of the load (308 mg) to offset the unbalanced load D to e.g. No. 1 screw hole18and No. 2 screw hole18in distribution, the mass balance of the rotary tool11can be adjusted appropriately. With this, the balance adjustment of the rotary tool11is completed.

(Runout Determining Step)

By the imaging device20, runout amounts of the rotary tool11are determined.

Specifically, in the course of rotation of the rotary tool11, the image sensor24of the imaging device20images (captures the images of) the rotary tool11and based on the obtained images of the rotary tool11, “shape data” of the blade portions5A of the tool5(rotary tool11) is obtained and with using the controller22(calculating section), from this shape data, the runout amount of the blade portion5A (rotary tool11) is determined.

The imaging device20effects the determination of the runout amounts of the plurality of blade portions5A of the rotary tool11with using either the dividing imaging method or the delayed imaging method described above. The dividing imaging method is an imaging technique for effecting a plurality of times of imaging operations during one rotation of a rotary body. On the other hand, the delayed imaging method is an imaging technique in which with use of an imaging cycle set slightly longer than the rotation cycle of the rotary body (one rotation cycle or plural rotation cycles), there is provided a stroboscopic effect to image the rotary body.

If the rotary tool11is used at a low rotational speed and the rotation cycle of the rotary tool11is equal to or greater than 2 folds of the maximum imaging cycle of the image sensor24(camera), the image sensor24can effect a plurality of times of imaging operations during one rotation of the rotary tool11. For this reason, in this case, by using the dividing imaging technique, the imaging device20can effect determination of runout amounts of the plurality of blade portions5A of the rotary tool11.

On the other hand, in case the rotary tool11is rotated at a high rotational speed and the rotation cycle of the rotary tool11is less than two folds of the maximum imaging cycle of the image sensor24(camera), the image sensor24cannot effect a plurality of imaging operations during one rotation of the rotary tool11. Thus, in this case, the imaging device20will effect determination of the runout amounts of the plurality of blade portions5A of the rotary tool11with using the delayed imaging technique instead of the dividing imaging technique. In this way, with selective use of two kinds of imaging techniques, the determination of runout amounts of the plurality of blade portions5A of the rotary tool11can be effected effectively.

In order to effect a high precision machining such as a mirror face machining on e.g. a precision metal mold by the rotary tool11, it is necessary to rotate this rotary tool11having the blade portions5A at a high speed. Then, in the following, with reference to the flowchart shown inFIG.14, a runout determining step of the rotary tool11with using the delayed imaging technique will be explained. At the runout determining step by the delayed imaging technique, the plurality of blade portions5A will be assigned with respective ID numbers (e.g.5A1,5A2, . . . n) in this order based on a determined start point and the tool5(rotary tool11) will be rotated continuously by a predetermined cycle, determination of runout displacements of the plurality of blade portions5A will be effected.FIGS.15through20show transition of the rotation phase of the tool5(rotary tool11) relative to the phase detecting portion31at the runout determining step.

At step #1, a determination cycle M is calculated. As one example, let us suppose a case in which the rotary tool11as the determination target is rotated at 5000 rpm and it has two blade portions5A. In this case, the rotation cycle of the rotary tool11becomes 12.00 milliseconds. Incidentally, here it is assumed that the minimum imaging interval time (the reciprocal of the maximum frame rate) of the camera having the image sensor24is 12.67 milliseconds. In this case, since the rotation cycle of the rotary tool11is less than two folds of the minimum imaging interval time of the camera, the delayed imaging technique will be implemented for determination of the runout amounts of the blade portions5A of the rotary tool11.

In the delayed imaging technique, a rotational speed (to be referred to as “delayed imaging rotational speed” hereinafter) for delaying the imaging timing of the image sensor24relative to the rotation cycle of the rotary tool11will be set by the controller22. With this, the initial imaging rotational speed is calculated with using Formula 8 below.
initial imaging rotational speed=rotational speed of rotary tool−delayed imaging rotational speed  [Formula 8]

For example, if the delayed imaging rotational speed is 5 rpm, then, the initial imaging rotational speed will become 4995 rpm.

Here, 4995 rpm calculated as the initial imaging rotational speed is converted to an imaging interval time of 12.01 milliseconds, which is shorter than the minimum imaging interval time of 12.67 milliseconds of the image sensor24. Therefore, it is not possible to use the imaging interval time of the image sensor24as the delayed imaging cycle (12.01 milliseconds). Then, 12.01 milliseconds, the imaging cycle converted from the initial imaging rotational speed, is multiplied by an integer (“2” in the instant embodiment) which gives a value greater than or equal to the minimum imaging interval time (12.67 milliseconds) of the imaging sensor24. With this, the imaging interval time of the image sensor24is set now to a time (24.02 milliseconds) which is slightly longer than two-rotation cycles of the rotary tool11, whereby the runout amounts of the blade portions5A can be determined appropriately. The imaging operation by the image sensor24is executed in response to output of a trigger signal from the trigger circuit29included in the controlling section28to the camera including the image sensor24.

Next, at step #2, an imaging start phase is set based on the position of the first mark3as the start point. And, a delay time W until start of the initial imaging operation is calculated. In this embodiment, the imaging start phase is set to 0.75 turn (rotation) and the delay time W is set to 9 milliseconds.

At step #3 through step #13, the runout amounts of the blade portions5A of the tool5are determined.

At step #3, the first mark3(fourth mark14) as the start point is detected by the phase detecting section31(seeFIG.15). At step #4, the blade portion5A1is set as the initial determination blade (N=1). Then, an imaging operation is started after lapse of the delay time W and the process starts detection of a maximum value of the positions of the blade portion5A1(the distances from the rotational axis Z of the rotary tool11to the outer face of the blade portion5A) (step #5, step #6, seeFIG.16).FIG.16shows a rotation phase of the tool5(rotary tool11) upon start of the imaging of the blade portion5A1.

As the imaging by the determination cycle M is continued, the maximum value of the positions of the blade portion5A1is updated (revised) at any time (step #7, step #8).FIG.17shows a rotation phase of the tool5at time of completion of a half of the imaging area of the blade portion5A1. At step #9, the process checks whether the imaging of the imaging area of the blade (blade portion5A1) in the N'th order (e.g. the first one) is completed or not. If the imaging of the imaging area is not yet completed, the process returns to step #7 and the imaging of the blade portion5A1is continued. When the imaging of the imaging area of the blade portion5A1is completed, the maximum value of the position of the blade portion5A1is recorded (step #10). This maximum value of the position of the blade portion5A1will be stored in the controlling section28of the imaging section21or in an unillustrated calculating section provided in the controller22. At step #10, the respective maximum values of the number of blades (N units) of the blade portions5A are stored.FIG.18shows a rotation phase of the tool5upon start of the imaging of the blade portion5A2.FIG.19shows a rotation phase of the tool5at time of completion of a half of the imaging area of this blade portion5A2.FIG.20shows a rotation phase of the tool5upon completion of the entire imaging operation of the imaging area of the blade portion5A2.

At step #11, the process checks whether the imaging operation has been completed for the target number of blades N or not. If the operation for the target number of blades N has not yet been completed, the maximum value of the position of the blade portion5A1will be reset and determination on the next blade (the blade portion5A2in this embodiment) is effected (step #12, step #6). On the other hand, if the completion of the operation for the target number of blades N is completed at step #11, at step #13, runout amounts of the plurality of blade portions5A of the rotary tool11are calculated.

FIG.21shows a relation between the rotation waveform (sine waveform) of the rotary tool11and the determination cycle M of the position of the blade portion5A of the rotary tool11(imaging interval time of the image sensor24). When the phase detecting section31detects the first mark3and then upon lapse of the delay time W thereafter, an external triggering from the trigger circuit29is activated, whereby a shutter (not shown) of the camera including the image sensor24is opened and closed. With this, the first imaging of the tool5of the rotary tool11by the image sensor24is effected. Thereafter, after lapse of every determination cycle M, an imaging by the image sensor24will be repeated.

[Runout Adjusting Step]

Based on the determination results of the runout determining step, the runout amounts of the plurality of blade portions5A of the rotary tool11are adjusted. Specifically, in the tool holder10, the clamping amount(s) of the screw member(s)41assembled in one or some of the screw holes18will be adjusted. More particularly, such screw member41will be clamped progressively toward the bottom face of the screw hole18. With this, the ball body40placed in contact with the leading end face of the screw member41presses the bottom portion of the screw hole18(the inner face of the second hole portion18b). The screw hole18is slanted to be closer to the axis of the tool holder10as it extends toward the base end side of the tool holder10. Therefor, in response to the clamping of the screw member41, the leading end of the chuck portion17will receive a reaction force of the screw member41which acts on the base end portion of the tool holder10.

With the above, in the chuck portion17, a portion thereof extending from the portion of the screw hole18in which the screw member41is clamped to the leading end becomes deformable to the radially outer side. By appropriately changing the clamping amounts of the screw member(s)41selected from the screw members41assembled in the plurality of screw holes18, adjustment is made possible for minimizing the runout amounts of the plurality of blade portions5A in the rotary tool11.

Here, preferably, in the axial direction of the screw member41, the contact area between the screw member41and the ball body40should be as small as possible. With decrease of the contact area between the screw member41and the ball body40in the axial direction, the contact resistance between these two members becomes smaller correspondingly. Namely, the efficiency of pressing is improved when the ball body40is pressed by the screw member41by tightening of this screw member41. This in effect can increase the pressing force exerted by the ball body40to the bottom portion of the screw hole18, so that the deformation amount of the chuck portion17can be increased easily. For the purpose of decreasing the contact area between the screw member41and the ball body40, alternatively a protruding portion having a smaller diameter than the main body of the screw member41may be provided at the leading end side axial portion of the screw member41, for instance.

Second Embodiment

In this embodiment, the delayed imaging technique used at the runout determining step differs from that used in the first embodiment whereas the rest of the configuration is identical to the first embodiment.

The runout determination of the rotary tool11by the delayed imaging technique in this embodiment is effected in accordance with a flowchart shown inFIG.22. Specifically the following steps are effected. For the plurality of blade portions5A, based on a set start point, ID serial numbers will be assigned to the respective blade portions5A (e.g.5A1,5A2, . . . n) in this order and the tool5is rotated continuously and determination of the positions of the blade portions5A will be effected with setting the determining cycle M (imaging interval time) longer than the rotation cycle (reference cycle M1).

At step #21, the process calculates a reference cycle M1and a “phase wait time (α)” which is to be added upon lapse of each reference cycle M1after detection of the first mark3as the start point by the phase detecting section31. In case the rotary tool11as the determination target is rotated at 5000 rpm and there are provided two blade portions5A, like the example disclosed in the first embodiment, the reference cycle M1will be a cycle in which the rotary tool11is rotated two turns (24 milliseconds) and the phase wait time (α) can be calculated by the following Formula 9 below.

[Formula⁢9]phase⁢wait⁢time⁢(a)=(one⁢rotation⁢cycle⁢of⁢rotary⁢tool)/(the⁢number⁢of⁢imaging⁢operations⁢per⁢one⁢rotation⁢of⁢the⁢rotary⁢tool).

For instance, in case the rotary tool11is imaged one time for each 1 degree rotation angle, the one rotation cycle 12 milliseconds and the imaging times 360 times will be substituted in Formula 9. With this, there is obtained a phase wait time (α) of 0.033 millisecond.

At steps #22 through #30, the positions of the plurality of blade portions5A of the tool5(the distances from the rotational axis Z of the rotary tool11to the outer faces of the blade portions5A) are determined. At step #22, upon detection of the first mark3as the start point by the phase detecting section31, the imaging operation by the image sensor24is started and detection of the maximum value of the positions of the blade portion5A1is started.

At step #24, after lapse of the reference cycle M1, upon detection of the first mark3as the start point by the phase detecting portion31, the phase wait time (α) is added up (step #25). For example, in the case of the second imaging, the phase wait time is (α). In the case of the third imaging, the phase wait time becomes 2α (seeFIG.23). At step #26, the maximum value of the position of the blade portion5A1is updated at any time if needed. Specifically the maximum value will be updated if the value of the position (position: n) of the blade portion5A1determined is greater than the value of the position (position: n−1) determined immediately prior thereto. In the determination of the position of the blade portion5A1, if the value of the position (position: n) becomes smaller than the value of the position (position: n−1) determined immediately before (step #27: Yes), the current maximum value is recognized as the cutting edge position having the peak value and will be recorded as such (step #28). At step #28, the maximum value of the number of blades (N units) of the blade portions5A is stored. At step #28, if the condition: position (n)<(position n−1) is not satisfied (step #27: No), then, the process returns to step #24 to continue the imaging operation.

At step #29, fulfillment of the target number N is checked, if not fulfilled yet, determination of the next blade portion5A (blade portion5A2in this embodiment) is effected (step #30, step #23). At step #29, if the fulfillment of the target number N is confirmed (or if the added-up value of the phase wait time (α) becomes one rotation amount of the rotary tool11), then, at step #31, the runout amounts of the plurality of blade portions5A of the rotary tool11are calculated.

FIG.23shows a relation between the rotation waveform (sine waveform) of the rotary tool11and the determination cycle M of the position of the blade portion5A of the rotary tool11(imaging interval time of the image sensor24).FIG.23shows an example in which the position of the first mark3as the start point is the imaging start phase. Namely the delay time W from the detection of the first mark3by the phase detecting section31to the start of the first imaging is zero (no phase wait).

As shown inFIG.23, in the first imaging of the tool5by the image sensor24, when a photoelectric sensor of the phase detecting section31detects the first mark3, an external trigger from the trigger circuit29is activated immediately whereby the shutter (not shown) of the camera including the image sensor24is opened and closed. The second imaging is effected after addition of the phase wait time (α) to the reference cycle M1(two-rotation cycle). Thereafter, at each time the photoelectric sensor of the phase detecting section31detects the first mark3at the reference cycle M1(two-rotation cycle), the phase wait time (α) is added. In this way with setting the determination cycle M (imaging interval time) longer than the rotation cycle (reference cycle M1), the determination of the position of the tool5is effected. Alternatively the determination may be made with detection of only a predetermined determination cycle M longer than the rotation cycle (reference cycle M1), without addition of the phase wait time (α) on each occasion of detection of the first mark3.

OTHER EMBODIMENTS

(1) The balance and runout adjustment system100may be alternatively configured to determine the mass balance of the rotary tool11with using e.g. a field balancer as the balance determining device.

(2) In the foregoing embodiment, there was disclosed an example in which the balance and runout adjustment system100effects a balance determining step and a balance adjusting step first and then effects a runout determining step and a runout adjusting step. However, the system100may be configured alternatively to effect a runout determining step and a runout adjusting step firstly and then effect a balance determining step and a balance adjusting step.

(3) In the foregoing embodiment, there was disclosed an example in which in the tool holder10, the ball body40and the screw member41(insertion member) are inserted and assembled into the screw hole18(insertion hole). Alternatively it may be arranged to press the bottom portion of the screw hole18with using a pressing member having a cylindrical shape or an angular post-like shape or any other shape, instead of the ball body40. For decreasing the contact area between such pressing member and the screw member41, the leading end axial portion of the screw member41may be formed with a smaller diameter than the main body portion of the screw member41or at least one of the opposed end faces where the screw member41and the pressing member come into contact with each other may be formed as a curved protruding portion. Further alternatively into the screw hole18(insertion hole), only the screw member41(insertion member) may be inserted and assembled. In this case, the leading end side of the screw member41needs to have a shape that allows contact with the bottom portion of the screw hole18(the inner face of the second hole portion18b).

(4) In embodying the invention, the tool holder10can be any such holder which is attached to the spindle2of the machine tool1and to which the tool5is to be attached.

INDUSTRIAL APPLICABILITY

The present invention can be widely used for adjustment of mass balance and runout amount of a rotary tool.

REFERENCE SIGNS LIST

1: machine tool2: spindle3: first mark4: second mark5: tool5A: blade portion10: tool holder11: rotary tool13: third mark14: fourth mark19: flange-like portion (intermediate portion)19a: end face18: screw hole (insertion hole)20: imaging device (balance determining device, runout determining device)21: imaging section22: controller (calculating section)23: beam projecting section24: image sensor28: control board (controlling section)29: trigger circuit31: phase detecting section40: ball body41: screw member (insertion member)100: balance and runout adjustment systemS: reference lineV1, V2, V3: vectorZ: rotational axis