JP2008046010A - Method for measuring the external shape of a round bar workpiece - Google Patents

Abstract

An object of the present invention is to provide a measurement method capable of reducing the focal position adjustment of an imaging device and measuring the outer shape of a round bar-shaped workpiece efficiently and accurately.
A directing the axis Ra of the round bar of the workpiece 70 and the rotary shaft C ₀ in at least the same direction, the gripping step of gripping the workpiece 70 in a rotatable state about the rotary axis C _0, the design of the workpiece 70 Based on the data, the process of calculating the rotation locus of the work 70 around the rotation axis C ₀ , and the optical axis of the imaging device and the axis of the work 70 based on the calculation result in the calculation process in synchronization with the rotation of the work 70 The image forming apparatus includes an arranging step of arranging the imaging device and the workpiece 70 relative to each other so that Ra is orthogonal to each other so that the measuring portion of the workpiece 70 is in focus, and an imaging step of imaging the measuring portion of the arranged workpiece 70.
[Selection] Figure 8

Description

  The present invention relates to a measuring method for measuring the outer shape of a round bar-shaped workpiece.

  As a measuring device for measuring the outer shape of a round bar-shaped workpiece, a tool holding means, a rotation driving means for rotating the tool holding means around the axis, and the tip of the bar-shaped cutting tool held by the tool holding means in the axial direction and the axis 2. Description of the Related Art A measuring apparatus for a rod-shaped cutting tool provided with imaging means for imaging from two directions of the Z-axis direction orthogonal to the direction is known (Patent Document 1).

  In the measurement method using the measurement apparatus, the three-dimensional coordinates of the plurality of measurement points are obtained by imaging the plurality of specified measurement points from two directions using the imaging unit. From this three-dimensional coordinate, the shape parameter of the tip of the bar-shaped cutting tool at a viewpoint other than the two directions is calculated and obtained. Therefore, the shape parameter can be measured without changing the viewpoint (image capturing angle) of the image pickup means corresponding to the shape of the tip.

  As a holding means for holding a round bar-shaped workpiece, as shown in FIG. 11, a chuck device 90 that grips a blade as a workpiece rotatably is known (Patent Document 2). The chuck device 90 includes a tool clamping unit 91 whose tip side is divided into three parts, and an operating body 92 that clamps the tool clamping unit 91 and grips the cutting tool.

JP 2001-59713 A JP 2003-334706 A

  In the above measuring apparatus, if the rod-shaped cutting tool is not held by the tool holding means in the correct posture so that the rotation axis of the rotation driving means and the axis of the rod-shaped cutting tool coincide with each other, shaft wobbling occurs. When imaging is performed by rotating the workpiece, there is a problem that the focal point by the imaging means is not determined if axial blurring occurs, and three-dimensional coordinates of a plurality of measurement points cannot be obtained accurately.

  Further, even when the chuck device 90 shown in FIG. 11 is used as the tool holding means, when the work to be measured is an extremely thin round bar, the work is caught in the gap 93 when the work is inserted into the tool holding portion 91. It is easy and may not be held in the correct posture.

  Further, when the workpiece measurement site is finely processed, the imaging means needs an optical system for enlarging the workpiece measurement site. The higher the magnification of the optical system, the shallower the depth of focus. Therefore, there is a problem that it is necessary to frequently adjust the focal position in synchronization with the rotation of the workpiece so that the workpiece does not deviate from the focal range.

  The present invention has been made in consideration of the above-described problems, and has an object to provide a measurement method capable of efficiently and accurately measuring the outer shape of a round bar-shaped workpiece by reducing the focus position adjustment of the imaging device. To do.

  A method for measuring the outer shape of a round bar-shaped workpiece according to the present invention is a measuring method for measuring the outer shape of a round bar-shaped workpiece using an imaging device, wherein the axis of the workpiece and the rotation axis are at least in the same direction, and the rotation axis is set. A gripping process for gripping a workpiece in a state that it can rotate around the center, a calculation process for calculating the rotation trajectory of the workpiece around the rotation axis based on the workpiece design data, and a calculation process in synchronization with the rotation of the workpiece Based on the result of the calculation, the optical axis of the imaging device and the axis of the workpiece are orthogonal to each other, an arrangement step for arranging the imaging device and the workpiece relative to each other so that the measurement site of the workpiece is focused, and a measurement site of the arranged workpiece And an imaging step of imaging.

  According to this method, in the gripping process, the workpiece is gripped so that the axis of the workpiece and the rotation axis are at least in the same direction. Therefore, the workpiece can be rotated around the rotation axis in a state where the axis of the workpiece and the rotation axis are always parallel. Therefore, the axis does not shake due to the rotation of the workpiece. In the calculation step, the rotation trajectory of the workpiece about the rotation axis is calculated based on the workpiece design data. In the arranging step, the imaging device and the workpiece are relatively arranged based on the obtained rotation trajectory of the workpiece. Therefore, compared with the case where the position of the workpiece with respect to the imaging device is searched and the focal position is adjusted, the workpiece can be quickly positioned in the imaging range and the focal position can be adjusted. That is, since it is possible to reduce the focal position adjustment of the image pickup apparatus and to pick up an image without blurring the axis, it is possible to provide a measurement method capable of measuring the outer shape of the round bar work efficiently and accurately.

  In the gripping step, the workpiece is gripped in a state where the workpiece axis and the rotation axis coincide. According to this method, the work is gripped so as to rotate about the axis. Therefore, if the imaging device and the workpiece are relatively arranged in the arrangement step, the adjustment of the focal position with respect to the measurement site synchronized with the rotation of the workpiece can be omitted. In addition, even when different workpieces manufactured based on design data having the same external shape are gripped, the focal position with respect to the measurement site can be quickly adjusted.

  In the gripping step, the workpiece may be gripped in a state where the workpiece axis and the rotation axis do not match. Once the workpiece is adjusted so that the axis line and the rotation axis are gripped with respect to the workpiece, when the workpiece having a different shaft diameter is gripped, the axis line of the workpiece and the rotation axis are shifted. Even in such a case, according to this method, in the calculation step, the rotation trajectory of the workpiece around the rotation axis is calculated based on the design data of the workpiece. It can be positioned quickly and the focal position can be adjusted. That is, it is possible to provide a measurement method that can efficiently measure workpieces having different shaft diameters.

  The workpiece has at least two shaft portions that are substantially concentric with different shaft diameters. In the gripping step, one of the two or more shaft portions is gripped. A rotation locus of the other shaft portion with respect to the shaft portion is calculated, and in the imaging step, a measurement site of the other shaft portion of the workpiece is imaged.

  According to this method, in the calculation step, the rotation trajectory of the other shaft portion with respect to one shaft portion around the rotation axis is calculated based on the design data of the workpiece. Even for a workpiece having a shaft portion that is substantially concentric, the focal position can be easily adjusted with respect to the measurement site of the other shaft portion, and measurement can be performed with high accuracy.

  Further, the workpiece has at least two or more non-concentric shaft portions having different shaft diameters, and in the gripping process, grips one shaft portion of at least two or more shaft portions, and in the calculation step, The rotation locus of the other shaft portion with respect to one shaft portion may be calculated, and in the imaging step, the measurement site of the other shaft portion of the workpiece may be imaged.

  According to this method, in the calculation step, the rotation trajectory of the other shaft portion with respect to one shaft portion around the rotation axis is calculated based on the design data of the workpiece, so that at least two or more shaft diameters different from each other are calculated. Even for a workpiece having a non-concentric shaft part, the focal position can be easily adjusted with respect to the measurement part of the other shaft part, and measurement can be performed with high accuracy.

  In addition, a rotation process is provided in which the workpiece is sequentially rotated around the rotation axis in a plurality of times, and in the calculation process, the position of the measurement part of the workpiece on the rotation locus is calculated according to the rotation angle divided into the plurality of times. It is preferable to be characterized by this.

  According to this method, in the calculation step, the position of the measurement part of the workpiece on the rotation trajectory is calculated according to the rotation angle divided into a plurality of times. Therefore, in the arrangement step, the imaging device is operated according to the rotation divided into a plurality of times. And the workpiece can be relatively arranged at an appropriate imaging position. That is, by rotating the workpiece in a plurality of times and imaging in synchronization with this, it is possible to obtain a more accurate dimensional data by performing a plurality of measurements on the measurement site of the workpiece.

  In the present embodiment, a measurement method using a measurement device including a clamp mechanism that grips an extremely thin round bar-shaped workpiece in a rotatable state will be described as an example. In addition, the figure used for description is enlarged or reduced as appropriate.

  First, the measurement apparatus will be described with reference to FIGS. FIG. 1 is a schematic diagram illustrating a configuration of a measurement apparatus. As shown in FIG. 1, the measuring apparatus 100 includes a clamp mechanism 30 that grips an extremely thin round bar-shaped workpiece R in a rotatable state, a table 31 on which the clamp mechanism 30 is disposed, and a gripped workpiece R. And an imaging device 35 that images the workpiece R from the Z-axis direction orthogonal to the axis Ra. The imaging device 35 includes two camera units 36 and 37 as imaging means, and two illuminations 33 and 34 disposed to face the camera units 36 and 37. The camera units 36 and 37 and the illuminations 33 and 34 are disposed on the same table 32. In addition, an autofocus mechanism 38 that adjusts the focal points of the camera units 36 and 37 with respect to the workpiece R by moving the table 32 in the Z-axis direction is provided. The camera units 36 and 37 use, for example, a combination of a CCD as an image sensor and an objective lens that enlarges the measurement part of the workpiece R. In this case, the camera unit 36 and the camera unit 37 are configured to have different magnifications during imaging. As the illuminations 33 and 34, for example, a halogen lamp capable of obtaining high brightness is used, and the illumination brightness is set according to the imaging magnification of each camera unit 36 and 37. The autofocus mechanism 38 includes a drive unit that moves the table 32 in the Z-axis direction as a matter of course.

  In addition, the measuring apparatus 100 sets the table 31 to X so that at least a part of the gripped work R is positioned on the optical axes 33a and 34a between the camera units 36 and 37 and the lights 33 and 34, respectively. A drive unit (not shown) that moves in the axial direction and the Y-axis direction is provided. The drive unit has an X-axis motor and a Y-axis motor. For example, a servo motor or a pulse motor is used as the X-axis motor and the Y-axis motor.

  Furthermore, the control apparatus 40 which controls each part of the measuring device 100 is provided. The control device 40 includes a CPU 41, a memory 42 including an EPROM, an image processing unit 43, an X-axis motor control unit 44, a Y-axis motor control unit 45, and motor control that controls the motor 29 of the clamp mechanism 30. Part 46. The control device 40 is configured using a personal computer or the like, for example.

  The memory 42 stores design data of the workpiece R that is a measurement object, data that specifies a measurement site, and a measurement program. In addition, measurement coordinates in the measurement apparatus 100 are stored. The coordinates include an origin set in the positional relationship between the clamp mechanism 30 and the imaging device 35 and coordinates in the X, Y, and Z axis directions with the origin as a reference.

  FIG. 2 is a schematic perspective view showing the structure of the clamp mechanism. As shown in FIG. 2, the clamp mechanism 30 includes a gripping unit 10 that grips an extremely thin round bar-shaped workpiece R, a posture adjusting unit 20 that adjusts the posture of the gripped workpiece R, and a gripping unit 10 and a posture adjusting unit. And a motor 27 as a rotational drive unit that rotates the gripping unit 10 and the posture adjusting unit 20 together. As the motor 29, for example, a servo motor or a pulse motor is used.

  Between the bearing 27 and the motor 29, a position detection mechanism 28 that detects the origin position of the posture adjustment unit 20, and a sleeve-like connection that connects the rotation shaft of the motor 29 and the posture adjustment unit 20 via the bearing 27. A portion 29a is provided. Each of the above components is disposed on the surface of the support plate 25.

  The position detection mechanism 28 includes a position detection plate (dog plate) 28a, an attachment portion 28b of the dog plate 28a, and an origin sensor 28c. An attachment portion 28b is fixed to one shaft (not shown) of the posture adjusting portion 20 that is rotatably supported by the bearing 27. The origin sensor 28c uses, for example, a photomicrosensor in which a light emitting unit (not shown) and a light receiving unit (not shown) are arranged to face each other. Is disposed on the surface of the support plate 25 so as to cross between the two. The origin position is detected by the dog plate 28a shielding the optical axis between the light emitting unit and the light receiving unit. In this embodiment, a photomicrosensor having a detection position accuracy of 30 μm is used. When the rotation angle is converted, the origin can be detected with an accuracy of 0.1 °.

  The grip 10 includes a cradle arm 11, a cradle 1 attached to one end 11a of the cradle arm 11, a T-shaped presser arm 12, and a presser attached to the end 12a. 5 is provided. The workpiece R is gripped by the cradle 1 and the pressing portion 5.

  The posture adjustment unit 20 includes an arm guide 16 that guides the cradle arm 11 and a hollow block 21 that serves as a position adjustment unit that supports the other end 11 b of the cradle arm 11. Further, the rotary table 18 in which the arm guide 16 and the block 21 are disposed, and the rotary plate 24 that is supported by the bearing 27 and to which the block 21 is attached are provided. The arm guide 16 and the rotary table 18 constitute a shake adjusting unit 15 that adjusts the shake of the cradle arm 11 with respect to the block 21.

  Therefore, when the motor 29 is driven, the rotating plate 24 supported by the bearing 27 rotates. Since the rotary table 18 is fixed to the rotary plate 24 via the block 21, the cradle arm 11 supported by the block 21 and the arm guide 16 rotates. That is, the workpiece R is rotated around the rotation axis of the motor 29 while being gripped by the grip portion 10.

  FIG. 3 is a front view showing the grip portion. In detail, it is the front view which looked at the holding part 10 from the X-axis direction. As shown in FIG. 3, the cradle 1 has a V-shaped groove 2. The pressing portion 5 has a tip portion 6 that fits in the groove portion 2. The workpiece R is inserted into the groove portion 2 of the cradle 1 and is pressed and gripped by the tip portion 6 of the pressing portion 5.

  Further, as shown in FIG. 3, the arm guide 16 of the posture adjusting unit 20 is formed in an L shape, and the bottom thereof is fixed to the rotary table 18. On the side surface, two lock screws 19 and a Y-axis adjusting screw 17a that are spaced apart in the X-axis direction are provided. In addition, two Z-axis adjusting screws 17b that pass through the rotary table 18 and the arm guide 16 from below (Z-axis direction) are provided.

  Therefore, the cradle arm 11 to which the cradle 1 is attached is supported by the Y-axis adjusting screw 17a and the Z-axis adjusting screw 17b. By adjusting the screwing amount of each of the adjusting screws 17a and 17b, the shake of the cradle arm 11 in the Y-axis direction and the Z-axis direction can be adjusted. That is, the Y-axis adjustment screw 17a, the Z-axis adjustment screw 17b, and the lock screw 19 are included in the shake adjustment unit 15 (see FIG. 2) of the cradle arm 11.

  FIG. 4 is a schematic view showing details of the cradle. The figure (a) is a perspective view, the figure (b) is the top view seen from the A direction of the figure (a).

  As shown in FIG. 4 (a), the cradle 1 includes a V-shaped groove 2 composed of two slopes 2a and 2b, and four recesses 3a provided in a direction perpendicular to the extending direction of the groove 2. 3b, 4a, 4b and two screw holes 1a, 1b for attachment. When viewed from above the cradle 1, the pair (one set) of recesses 3 a and 3 b provided with the groove 2 interposed therebetween is provided at a position entering the inside from the insertion side of the workpiece R. The other pair of recesses 4a and 4b is provided so as to be separated from the one recess 3a and 3b and to cut out the side surface of the cradle 1. In other words, it is provided facing the cradle arm 11 (see FIG. 2) having a function of stopping the workpiece R.

  As shown in FIG. 4B, the pair of recesses 4a and 4b are provided so as to be smaller than the depth of the groove 2 corresponding to the diameter of the workpiece R and to cut out a part of the corresponding inclined surfaces 2a and 2b. It has been. Therefore, the workpiece R is inserted along the groove 2 and abuts against the cradle arm 11. Moreover, insertion of the workpiece | work R is not inhibited by the recessed parts 4a and 4b.

  When the diameter of the workpiece R is very thin, a pair of recesses 4a and 4b may be provided so as to cut out all the corresponding two inclined surfaces 2a and 2b. Further, if the workpiece R can be supported by at least two inclined surfaces 2a and 2b, the bottom of the groove 2 may be a flat surface. The method for forming the recesses 3a and 3b is the same.

  Such a cradle 1 is screwed to the end portion 11a of the cradle arm 11 so that the long axis direction of the cradle arm 11 shown in FIG.

  FIG. 5 is a schematic view showing details of the pressing portion. FIG. 4A is a perspective view, and FIG. 4B is a plan view seen from the direction B of FIG.

  As shown in FIG. 5A, the pressing portion 5 has a tip portion 6 that fits in the groove portion 2 of the cradle 1. The tip 6 has two slopes 6 a and 6 b having the same inclination angle as the slopes 2 a and 2 b of the groove 2, and a plane 6 c that is parallel to the extending direction of the groove 2. Moreover, it has the convex parts 7a and 8a which protruded on the slope 6a side so that it may orthogonally cross the plane 6c, and the convex parts 7b and 8b which protruded on the slope 6b side. The pair (one set) of convex portions 7 a and 7 b is formed at the tip portion 6 at a position corresponding to the pair of concave portions 3 a and 3 b formed in the cradle 1. Similarly, a pair of convex parts 8a and 8b are formed in the front-end | tip part 6 in the position corresponding to a pair of recessed parts 4a and 4b.

  As shown in FIG. 5 (b), the convex portions 7a, 7b, 8a, 8b are arranged in the horizontal direction on the paper surface so that the bottom surfaces 7c, 8c form the same plane as the plane 6c of the tip portion 6. It protrudes from the slopes 6a and 6b. That is, the tip 6 is formed so as to cross the groove 2 of the cradle 1. The pressing portion 5 is provided with a notch 9 that fits into one end 12a of the pressing portion arm 12 and a hole 9a through which a fixing screw passes.

  The workpiece R inserted into the groove 2 is supported by the groove 2 and pressed by the flat surface 6 c of the pressing portion 5. Moreover, each convex part 7a, 7b, 8a, 8b is settled in each recessed part 3a, 3b, 4a, 4b of the cradle 1, respectively. Therefore, even if the insertion position of the workpiece R with respect to the groove 2 is deviated, the workpiece R is guided to a predetermined position along the groove 2 by the convex portions 7a, 7b, 8a, 8b.

  Further, for example, in order to place the workpiece R in the groove portion 2 in a more correct posture, in the insertion direction of the workpiece R, the recesses 3a and 3b are provided on the side surface of the cradle 1 in the same manner as the recesses 4a and 4b. Can be considered. Then, when inserting the workpiece R into the groove 2, when viewed from the operator, the groove 2 is hidden by the convex portions 7 a and 7 b of the pressing portion 5, which may cause an insertion error. In this case, since the recesses 3a and 3b are provided on the inner side of the cradle 1, the entrance of the groove 2 is not hidden by the protrusions 7a and 7b that fit into this, and the workpiece R can be inserted into the groove 2 more reliably. Is possible (see FIG. 4).

  In addition, each convex part 7a, 7b, 8a, 8b does not necessarily need to be provided in the direction orthogonal to the extension direction of the groove part 2. FIG. For example, it is preferable to form the convex portions 7a, 7b, 8a, and 8b and the corresponding concave portions 3a, 3b, 4a, and 4b so as to open in a reverse C shape with respect to the insertion direction of the workpiece R. . According to this, insertion of the workpiece | work R is hard to be inhibited by each recessed part 3a, 3b, 4a, 4b. Furthermore, the slopes 6a and 6b are not essential, and the front end portion 6 may have a flat surface 6c for gripping the workpiece R and each of the convex portions 7a, 7b, 8a and 8b. Further, the convex portions are not limited to two sets, and even one set can be expected to have the effect, and may be increased further.

  FIG. 6 is a perspective view showing details of the gripping part and the posture adjusting part. Specifically, it is a diagram showing the block 21 and the arm guide 16 as seen through.

  As shown in FIG. 6, in the gripping part 10, the pressing part arm 12 is supported by a shaft 13 with a support part 12 c housed in a long hole 11 c provided in the cradle arm 11. The pressing portion 5 is screwed to one end portion 12a. Between the other end portion 12 b and the cradle arm 11, a spring 14 is provided as a biasing portion that biases the pressing portion 5 toward the groove portion 2. The urging portion is not limited to the spring 14 and may be an elastic body such as rubber. Further, the pressing portion 5 is screwed to the end portion 12a of the pressing portion arm 12 so that the major axis direction of the pressing portion arm 12 and the extending direction of the flat surface 6c coincide with each other. That is, the pressing portion 5 is urged by the spring 14 with the support portion 12 c of the pressing portion arm 12 as a fulcrum, and the distal end portion 6 is accommodated in the groove portion 2 of the cradle 1.

  In the attitude adjustment unit 20, one end 11 a of the cradle arm 11 is supported by the shake adjustment unit 15. The cradle 1 is attached to the tip of one end 11a with a screw 11d. The other end portion 11b is inserted into the hollow portion 21a of the block 21, and a pair of Z-axis tilt adjusting screws 22a and 22b that penetrates the block 21 in the Z-axis direction, and a pair of Y that penetrates the block 21 in the Y-axis direction. It is supported from four directions by shaft inclination adjusting screws 22 c and 22 d and is fixed to the block 21.

  The rotary plate 24 supported by the bearing 27 is provided with a quadrangular columnar shaft 24a that protrudes toward the block 21 side. The shaft 24a is inserted into the hollow portion 21a of the block 21, and a pair of Z-axis offset adjusting screws 23a and 23b that penetrates the block 21 in the Z-axis direction, and a pair of Y-axis offset adjustments that penetrate the block 21 in the Y-axis direction. It is supported from four directions by screws 23c and 23d and fixed to the block 21. As a result, the shaft 24 a of the rotating plate 24 and the end portion 11 b of the cradle arm 11 are indirectly connected via the block 21. That is, when the rotating plate 24 rotates, the gripping unit 10 and the posture adjusting unit 20 (blur adjusting unit 15, block 21) rotate together. The shaft 24a matches the rotation center of the motor 29, and rotates as the rotation shaft rotates. Therefore, the motor 29 rotates the grip unit 10 and the posture adjustment unit 20 together.

  According to such a clamp mechanism 30, the workpiece R inserted into the groove portion 2 is supported by the two inclined surfaces 2 a and 2 b and is pressed and gripped between the flat surface 6 c of the pressing portion 5. Therefore, the workpiece R is gripped so that the axis line Ra of the workpiece R and the extending direction of the groove portion 2 coincide with each other.

  Further, the two sets of convex portions 7a, 7b, 8a, 8b provided in the pressing portion 5 are provided so as to be accommodated in the two sets of concave portions 3a, 3b, 4a, 4b. Therefore, even if the workpiece R is inserted into the groove portion 2 in an inclined state, each of the convex portions 7a, 7b, 8a, 8b guides the workpiece R so as to fit in a predetermined position along the inclined surfaces 2a, 2b of the groove portion 2. .

  The gripping unit 10 is supported by an attitude adjusting unit 20 including an arm guide 16 and a rotary table 18 and a block 21, and rotates integrally. The shake of the axis line Ra of the workpiece R is adjusted by the adjustment screws 17a, 17b of the shake adjustment unit 15 and the inclination adjustment screws 22a, 22b, 22c, 22d of the block 21. The relative positions of the shaft 24a and the axis line Ra of the workpiece R can be substantially determined by the offset adjusting screws 23a, 23b, 23c, and 23d of the block 21. Therefore, if the screwing amounts of the respective offset adjusting screws 23a, 23b, 23c, and 23d are adjusted so that the shaft 24a and the axis line Ra coincide with each other, the rotation axis of the motor 29 and the axis line Ra of the work R are made to coincide with each other. R can be rotated. Even if they do not match, the rotation axis of the motor 29 and the axis line Ra of the workpiece R are offset by a predetermined distance, and the workpiece R gripped by the gripping portion 10 can be relatively rotated about the rotation axis. it can.

  According to such a measuring device 100, the CPU 41 of the control device 40 performs the work R when the work R is rotated around the rotation axis of the motor 29 based on the design data of the work R stored in the memory 42. The rotation trajectory of is calculated. Further, based on the calculation result, the axis line Ra of the work R gripped by the gripping unit 10 and the optical axis 33a (or the optical axis 34a) of the imaging device 35 are crossed so that a desired measurement site of the work R is focused. The auto focus mechanism 38, the image processing unit 43, the X-axis motor control unit 44, the Y-axis motor control unit 45, and the motor control unit 46 are controlled. Therefore, it is possible to adjust the focal position by quickly arranging the work R in an appropriate imaging range. In addition, since the workpiece R is gripped by the gripping unit 10 so as not to be shaken with respect to the rotation axis of the motor 29, it is possible to accurately capture an image even when the workpiece R is rotated around the rotation axis. .

<Method for measuring the external shape of a round bar-shaped workpiece>
Next, the measurement method of this embodiment is demonstrated based on FIGS. FIG. 7 is a schematic side view showing the workpiece of the first embodiment, and FIG. 8 is a diagram showing a workpiece measuring method of the first embodiment. FIG. 9 is a schematic diagram illustrating a workpiece according to the second embodiment, and FIG. 10 is a diagram illustrating a workpiece measuring method according to the second embodiment.

(Example 1)
As shown in FIG. 7, the workpiece 70 according to the first embodiment is a round bar having three shaft portions 71, 72, 73 having different shaft diameters. Each axial part 71,72,73 is substantially concentric with respect to the axis line Ra. Further, the thickness decreases from the shaft portion (main shaft) 71 to the shaft portion (sub shaft) 72 and the shaft portion (tip shaft) 73. For example, the shaft diameter d3 of the main shaft 71 is approximately 200 μm, the shaft diameter d2 of the auxiliary shaft 72 is approximately 100 μm, and the shaft diameter d1 of the tip shaft 73 is approximately 20 μm. Tapered portions are formed between the main shaft 71 and the sub shaft 72 and between the sub shaft 72 and the tip shaft 73, respectively. In this case, the shaft diameters d1, d2, and d3 and the dimensions a, b, c, and e are measured.

FIG. 8 illustrates a workpiece measuring method according to the first embodiment, and more specifically, illustrates the workpiece as viewed from the X-axis direction. In this case, in the clamping mechanism 30, the gripping unit 10 is gripped in advance, and the posture adjustment unit 20 is adjusted so that the axis line Ra of the work 70 and the rotation axis C _{0 of the} motor 29 match (axis adjustment step). . As an actual adjustment method, the work 70 is gripped and rotated by the clamp mechanism 30 and the state is imaged by the imaging device 35 to check whether there is any shake of the axis Ra.

Next, the operator inserts the main shaft 71 of the workpiece 70 into the groove portion 2 of the grip portion 10 and presses it with the pressing portion 5. As a result, the workpiece 70 is gripped in a state in which the axis line Ra of the workpiece 70 and the rotation axis C ₀ are directed in the same direction and are rotatable about the rotation axis C ₀ (gripping step). Then, the control device 40 is operated to start the measurement operation. First, the CPU 41 calculates a rotation locus when the workpiece 70 is rotated around the axis line Ra based on the design data of the workpiece 70 stored in the memory 42 (calculation step). That is, in this case, the concentric circles indicated by the solid lines in FIG. 8 indicate the rotation trajectory.

  Next, control signals are sent to the X-axis motor control unit 44 and the Y-axis motor control unit 45 based on the measurement program stored in the memory 42 and the calculated rotation locus. The X-axis motor control unit 44 and the Y-axis motor control unit 45 drive the X-axis motor and the Y-axis motor based on the control signal to set the table 31 so that the measurement site of the workpiece 70 is positioned on the optical axis 33a, for example. Move. Further, a control signal is sent to the autofocus mechanism 38 to drive the autofocus mechanism 38 so that the work unit 70 illuminated by the illumination 33 is focused on the camera unit 36. More specifically, the image processing unit 43 identifies the outer shape of the work 70 based on the image information captured by the camera unit 36, and the autofocus mechanism 38 is driven for focusing so that the outer shape line can obtain a predetermined sharpness. (Placement step).

  The image processing unit 43 converts image information captured in a focused state into bitmap data and sends it to the CPU 41. CPU41 calculates and outputs the dimension of a measurement part from this bitmap data (measurement process). In addition, the control device 40 sends a control signal to the motor control unit 46 to drive the motor 29 so as to rotate the work 70 in a plurality of times (rotation process). In synchronization with this, the measurement process of imaging the workpiece 70 is repeated a plurality of times, and the output data is statistically processed by the CPU 41 (dimension data processing process). Thereby, an average value and variation are obtained from a plurality of sampling data of the measurement site.

  Since the measuring apparatus 100 includes the clamp mechanism 30 that grips and rotates the workpiece 70 so that the axis Ra does not shake, when the sampling data is to be obtained a plurality of times, in the first measurement, If the focal position of the camera unit 36 is adjusted with respect to 70, even if the work 70 is rotated, it is not necessary to adjust the focal position again, and measurement can be performed. The same applies to the case where the workpiece 70 is replaced and measurement is continued for another workpiece 70. That is, the external shape of the work 70 can be measured with high accuracy, and the focal position adjustment between the work 70 and the camera unit 36 accompanying a plurality of measurements is simplified.

  The selection of the two camera units 36 and 37 having different imaging magnifications is incorporated in the measurement program according to the external dimensions of the work 70. For example, first, a low-magnification camera unit 36 is selected, and imaging is performed by adjusting the focal position with respect to the main shaft 71 and the sub shaft 72 having a large shaft diameter. Thereafter, a high-magnification camera unit 37 is selected, and the focal position is adjusted with respect to the fine tip shaft 73 to take an image. In this way, it is possible to shorten the time required compared to the case where the focal position is adjusted with respect to the distal end shaft 73 using the high-magnification camera unit 37.

  As a matter of course, each WD (Working Distance) of each of the camera units 36 and 37 having different imaging magnifications is input in advance to the memory 42 as one of positional information of the imaging device 35. Therefore, the control device 40 can easily position the workpiece 70 in the imaging range of each camera unit 36, 37.

As shown in FIG. 8, in the posture adjustment unit 20, when the position of the rotation axis C ₀ of the motor 29 and the axis line Ra of the work 70 do not match and is offset so as to be offset, The workpiece 70 rotates relatively. Therefore, it is necessary to adjust the focal position of the imaging device 35 with respect to the rotating workpiece 70. In this case, the CPU 41 calculates the X, Y, and Z axis coordinates of the workpiece 70 according to the rotation angle based on the design data of the workpiece 70 and the offset value (position information). For example, the rotation trajectory at the center of the tip shaft 73 is a trajectory T ₁ . Moreover, the locus | trajectory for every rotation angle of each axial part 71,72,73 is shown with an imaginary line. Based on the calculation result, the control device 40 sends control signals to the X-axis motor control unit 44 and the Y-axis motor control unit 45 so that the measurement part of the workpiece 70 is positioned on the optical axis 33a, for example, according to the rotation angle. The table 31 is moved. Further, a control signal is sent to the autofocus mechanism 38, and the table 32 is moved in the Z-axis direction so that the imaging device 35 is focused on the measurement part of the work 70. Then, the measurement process and the dimension data processing process as described above are performed in a plurality of times.

  If the above measuring method is used, each shaft diameter d1, d2, d3 and each dimension a, b, c, e can be measured with high accuracy. Thereby, the external shape of each axial part 71,72,73 and the length of a taper part can be calculated | required. Further, the eccentricity of the auxiliary shaft 72 and the tip shaft 73 with respect to the main shaft 71 can also be measured.

  If the measuring device 100 further includes a display device or a printing device, it is possible to display the dimension data output by the CPU 41, record it on paper, or display the image information of the work 70.

(Example 2)
FIG. 9 is a schematic view showing a workpiece of the second embodiment. The figure (a) is a side view, The figure (b) is a front view of the figure (a).

  As shown in FIGS. 9A and 9B, the workpiece 80 of the second embodiment is a round bar having two shaft portions 81 and shaft portions 82 having different shaft diameters. The axis Ra of the shaft portion (main shaft) 81 and the axis Rb of the shaft portion (tip shaft) 82 are not concentric. For example, the shaft diameter d4 of the main shaft 81 is approximately 300 μm, and the shaft diameter d5 of the tip shaft 82 is approximately 50 μm. A tapered portion is formed between the main shaft 81 and the tip shaft 82. In this case, the shaft diameters d4 and d5 and the dimensions f and g are measured.

Figure 10 shows a method of measuring the workpiece in Example 2, FIG. (A) shows a case of rotating the workpiece 80 about the axis Ra, FIG (b) the axis Ra relative to the rotational axis C ₀ is the Indicates an offset case.

As shown in FIG. 10A, in the axis adjustment step, the posture adjustment unit 20 of the measuring apparatus 100 performs adjustment in advance so that the axis line Ra of the workpiece 80 and the rotation axis C _{0 of the} motor 29 coincide. In the gripping process, the spindle 81 of the workpiece 80 is inserted into the gripping part 10 and gripped. When the workpiece 80 rotates, the non-concentric tip shaft 82 relatively rotates on a rotation locus around the axis line Ra (rotation axis C ₀ ). For example, the rotation locus of the axis Rb becomes the trajectory T _2. The locus for each rotation angle of the tip shaft 82 is indicated by an imaginary line. In the calculation step, these rotation trajectories are calculated based on the design data of the workpiece 80. In the arranging step, the imaging device 35 and the work 80 are relatively arranged in the imaging ranges of the camera units 36 and 37 based on the calculation result. The measurement program selects the arrangement position of the workpiece 80 based on the calculation result depending on whether the spindle 81 is measured or the tip axis 82 is measured. Hereinafter, the measurement process, the rotation process, and the dimension data processing process are the same as those in the first embodiment.

As shown in FIG. 10 (b), the orientation adjuster 20, respectively rotating shaft C ₀ when the rotary shaft C ₀ does not match, the main shaft 81 and the tip end shaft 82 of axis Ra and the motor 29 of the workpiece 80 Rotates relative to the center. For example, the rotation locus of the axis Ra rotation locus of the trajectory T _3, and the axis Rb becomes the trajectory T _4. Further, the trajectories of the main shaft 81 and the tip shaft 82 for each rotation angle are indicated by imaginary lines. In the calculation step, these rotation trajectories are calculated based on the design data of the workpiece 80. In the arranging step, the imaging device 35 and the work 80 are relatively arranged in the imaging ranges of the camera units 36 and 37 based on the calculation result. The measurement program selects the arrangement position of the workpiece 80 based on the calculation result depending on whether the spindle 81 is measured or the tip axis 82 is measured. Hereinafter, the measurement process, the rotation process, and the dimension data processing process are the same as those in the first embodiment.

  By using the measurement method of the second embodiment as described above, even the workpiece 80 having the non-concentric tip shaft 82 is effectively imaged by changing the angle substantially, and the shaft diameters d4 and d5 and the dimensions f and g. Can be measured accurately. Thereby, the external shape of each axial part 81 and 82 and the length of a taper part can be calculated | required. Further, the accuracy of the eccentricity of the tip shaft 82 with respect to the main shaft 81 can be measured.

The effect of the said embodiment is as follows.
In the measuring method of the round bar-shaped workpiece 70 of the above embodiment using the measuring apparatus 100, in the gripping process, the spindle 71 is inserted into the gripping portion 10 of the clamp mechanism 30, and the workpiece 70 is gripped in a rotatable state. The axis line Ra of the main shaft 71 is gripped so as not to shake with respect to the rotation axis C ₀ of the motor 29. In the calculation step, the rotation locus of the workpiece 70 rotating around the rotation axis C ₀ is calculated based on the design data of the workpiece 70. In the arrangement step, the imaging device 35 and the work 70 are relatively arranged based on the calculation result, and the autofocus mechanism 38 focuses on the measurement site. Therefore, in synchronism with the rotation of the workpiece 70, the focal position can be quickly adjusted and the measurement site can be imaged. In addition, since the workpiece 70 is gripped so as not to be shaken, imaging can be performed with high accuracy. Therefore, when the workpiece 70 is rotated and measured in a plurality of times, or when a plurality of workpieces 70 are exchanged and measured, the workpiece 70 is arranged with high positional accuracy, so that the focus position adjustment by the autofocus mechanism 38 is performed. It does not have to be performed frequently. That is, the outer dimension of the workpiece 70 can be accurately and efficiently measured. Further, the eccentricity of the shaft portions 72 and 73 with respect to the main shaft 71 can also be measured. The same applies to the workpiece 80 having the non-concentric shaft portions 81 and 82.

  As mentioned above, although embodiment of this invention was described, various deformation | transformation can be added with respect to the said embodiment in the range which does not deviate from the meaning of this invention. For example, modifications other than the above embodiment are as follows.

  (Modification 1) In the measurement method of the above embodiment, the method of gripping the workpieces 70 and 80 in a rotatable state is not limited to the clamp mechanism 30 of the measurement apparatus 100. You may attach to the rotating shaft of the motor 29 using the tool (jig tool) hold | gripped exclusively according to each workpiece | work 70,80.

  (Modification 2) In the measurement method of the above embodiment, the clamp mechanism 30 is gripped and rotated in advance, and the focal position of the imaging device 35 is adjusted according to each rotation angle. An operation of storing the X-, Y-, and Z-axis coordinates at this time in the memory 42 by the control device 40 may be performed. According to this, although it takes time to adjust the initial focus position, it is possible to cope with the case where the design data of the workpiece is unknown.

  (Modification 3) In the measurement method of the above embodiment, the arrangement of each part such as the clamp mechanism 30, the table 31, and the imaging device 35 of the measurement device 100 is not limited to this. For example, in FIG. 1, the clamp mechanism 30 is arranged on the table 31 so that the axis Ra of the round bar-shaped workpiece R and the Z-axis direction coincide with each other, and the optical axis 33a extends in a direction perpendicular to the axis Ra of the workpiece R. The camera unit 36 and the illumination 33 may be arranged so as to face each other. According to this, the workpiece R is inserted into the groove portion 2 of the cradle 1 from the Z-axis direction, and the operation is easier than when the workpiece R is inserted in the X-axis direction.

Schematic which shows the structure of a measuring device. The schematic perspective view which shows the structure of a clamp mechanism. The front view which shows a holding part. (A) is a perspective view which shows the detail of a receiving stand, (b) is the top view seen from the A direction of (a). (A) is a perspective view which shows the detail of a holding | suppressing part, (b) is the top view seen from the B direction of (a). The perspective view which shows the detail of a holding part and an attitude | position adjustment part. FIG. 2 is a schematic side view showing a work of Example 1. FIG. 3 is a diagram illustrating a workpiece measuring method according to the first embodiment. (A) is a side view which shows the workpiece | work of Example 2, (b) is a front view of (a). (A) is a figure which shows the measuring method of the workpiece | work of Example 2 which rotates a workpiece | work centering on an axis line, (b) is a figure which shows the measuring method of the workpiece | work of Example 2 by which the axis line was offset with respect to the rotating shaft. The schematic perspective view which shows the chuck device as a conventional clamp mechanism.

Explanation of symbols

35 ... imaging apparatus, 33a, 34a ... optical axis, 70, 80 ... round bar work, 71, 72, 73 ... shank a substantially concentric, 81, 82 ... shank is non-concentric, C ₀ ... rotary shaft , Ra... Axis, T ₁ , T ₂ , T ₃ , T ₄ ... Locus as a rotation locus.

Claims (6)

A measuring method for measuring the outer shape of a round bar-shaped workpiece using an imaging device,
A gripping step of gripping the workpiece in a state where the axis of the workpiece and the rotation axis are at least in the same direction and are rotatable around the rotation axis;
Based on the design data of the workpiece, a calculation step of calculating a rotation trajectory of the workpiece around the rotation axis;
In synchronization with the rotation of the workpiece, based on the calculation result in the calculation step, the optical axis of the imaging device and the axis of the workpiece are orthogonalized, and the imaging device and the workpiece are focused on the measurement site of the workpiece. And an arrangement process for arranging
An imaging method for measuring the outer shape of a round bar-shaped workpiece, comprising: an imaging step of imaging a measurement site of the placed workpiece.   The method for measuring the outer shape of a round bar-shaped workpiece according to claim 1, wherein, in the gripping step, the workpiece is gripped in a state where an axis of the workpiece and the rotation axis coincide with each other.   2. The method for measuring the outer shape of a round bar-shaped workpiece according to claim 1, wherein in the gripping step, the workpiece is gripped in a state where the axis of the workpiece does not match the rotation axis. The workpiece has at least two or more concentric shaft portions having different shaft diameters,
In the gripping step, one of the at least two shaft portions is gripped,
In the calculation step, a rotation locus of the other shaft portion with respect to the one shaft portion is calculated,
The method for measuring the outer shape of a round bar-shaped workpiece according to any one of claims 1 to 3, wherein in the imaging step, a measurement site of the other shaft portion of the workpiece is imaged. The workpiece has at least two or more non-concentric shaft portions having different shaft diameters,
In the gripping step, one of the at least two shaft portions is gripped,
In the calculation step, a rotation locus of the other shaft portion with respect to the one shaft portion is calculated,
The method for measuring the outer shape of a round bar-shaped workpiece according to any one of claims 1 to 3, wherein in the imaging step, a measurement site of the other shaft portion of the workpiece is imaged. Comprising a rotation step of rotating the workpiece sequentially around the rotation axis in a plurality of times,
The round bar shape according to any one of claims 1 to 5, wherein in the calculation step, a position of a measurement part of the workpiece on a rotation locus is calculated according to the rotation angle divided into the plurality of times. Measuring method of workpiece outline.

Images