Dimension measuring apparatus

Abstract

To suppress the resonance of a finger and to improve the dimension measuring accuracy of a work by changing the natural frequency of the finger by an inexpensive and simple method without sacrificing the measuring accuracy.SOLUTION: A dimension measuring device includes a gauge head abutting on a workpiece, a long member supporting the gauge head on a first end side and swingably supported by a body on a second end side, and shape changing means for changing a cross-sectional shape of the long member.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a dimension measuring device for measuring the shape or dimensions of a workpiece being processed, and in particular to a dimension measuring device having a means for changing the natural frequency of a finger used in the dimension measuring device. [Background technology]

[0002] Conventionally, a dimension measuring device has been known in which a finger with a contact at the tip is attached so as to be able to swing freely in the measurement direction and the retraction direction, and the finger is swung in the measurement direction to bring the contact into contact with the outer surface of the workpiece, and an electrical signal based on the amount of displacement is detected by a differential transformer to measure the outer diameter of the workpiece (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-027502 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional dimension measuring device described in Patent Document 1, when the finger resonates at its natural frequency, the vibration is transmitted to the contact at the tip of the finger, causing the tip of the contact to vibrate in the measurement direction according to the natural frequency of the finger. As a result, contact and non-contact states occur between the tip of the contact and the outer surface of the workpiece, and the amount of finger displacement changes according to the vibration of the finger, resulting in the problem that the outer diameter of the workpiece cannot be measured accurately.

[0005] To solve this problem, conventionally, when resonance occurs in the fingers, a mass (weight) is added to the base of the finger or parts in the finger area are replaced to avoid the resonance problem.

[0006] However, while adding a mass to the finger can suppress finger resonance, the increased mass also increases the moment of inertia, making displacement measurement unstable and reducing the accuracy of workpiece outer diameter measurement. Furthermore, replacing finger parts requires time and skill.

[0007] The present disclosure has been made in consideration of the problems with conventional dimension measuring devices described above, and aims to suppress finger resonance and improve the accuracy of workpiece dimension measurement by changing the natural frequency of the finger in a low-cost and simple manner without sacrificing measurement accuracy. [Means for solving the problem]

[0008] The dimensional measuring device disclosed herein is characterized by comprising a measuring probe that contacts a workpiece, a long member that supports the measuring probe at a first end and is swingably supported by a main body at a second end, and a shape changing means that changes the cross-sectional shape of the long member. [Effects of the Invention]

[0009] According to the present disclosure, by changing the natural frequency of the finger using a low-cost and simple method, resonance of the finger is suppressed and the accuracy of measuring the dimensions of the workpiece is improved. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic perspective view showing an example of use of a dimension measurement system including a dimension measurement device according to an embodiment. [Figure 2] FIG. 2 is a partial cross-sectional schematic view of a dimension measuring device according to an embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view taken along dashed line AA of the finger of the dimension measuring device shown in FIG. [Figure 4] FIG. 4 is a cross-sectional view showing a modification of the finger shown in FIG. [Figure 5] FIG. 5 is a cross-sectional view showing another modification of the finger shown in FIG. [Figure 6] FIG. 6 is a cross-sectional view showing a modification of the finger shown in FIG. [Figure 7] FIG. 7 is a cross-sectional view showing another example of a finger. [Figure 8] FIG. 8 is a cross-sectional view showing a modification of the finger shown in FIG. [Figure 9A] 9A is an enlarged front view showing the operation of the inner diameter clamp shown in FIG. 8. FIG. [Figure 9B] 9B is an enlarged front view showing the operation of the inner diameter clamp shown in FIG. [Figure 10] FIG. 10 is a schematic partial cross-sectional view of another example of a dimension measuring device. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of a dimension measuring device according to the present disclosure will be described with reference to the drawings. Note that the same reference numerals are used to designate the same components throughout the drawings. Furthermore, the embodiments shown in the drawings are merely examples and do not limit the present disclosure in any way. Furthermore, the embodiments and their variations described below can be combined in any manner, and such combinations are within the scope of the present disclosure.

[0012] FIG. 1 is a schematic perspective view showing an example of use of a dimension measurement system including a dimension measurement device according to an embodiment. The dimension measurement system 1 includes a pair of dimension measurement devices 60 that measure the outer diameter of a workpiece W and a control device 20 that controls the operation of the dimension measurement devices 60 and processes signals from the dimension measurement devices 60. In this example, for convenience of explanation, the dimension measurement devices 60 are shown as a pair separated in the Z-axis direction, but this is not limited to this and they may also be configured as an integrated unit. The workpiece W may be, but is not limited to, a CNC (Computer Numerical Control) machined part or the like. The workpiece W may be stationary or rotating about its central axis. The control device 20 and a compressed air source (not shown) may be attached to a general-purpose measuring head (not shown). Note that the dimension measurement device 60 in this example is a device that measures the outer diameter of the workpiece W, but the parameter (dimension) measured is not limited to the outer diameter. It may also be the inner diameter of the workpiece W as long as it is measured by contacting a measuring probe. The dimension measuring device may also be for plane measurement (for measuring height, thickness, etc.), and may be incorporated into a back grinder in the semiconductor manufacturing process.

[0013] The control device 20 is connected by wire or wirelessly to the operator's work terminal 10, the compressed air source, and the differential transformer 180 provided in the dimension measuring device 60. The dimension measuring device 60 has a probe 300 attached to the tip end of a long finger extending in the Y-axis direction (described later), and a differential transformer 180 attached to the rear end, opposite the probe 300. In response to a command issued through the operator's work terminal 10, the control device 20 controls the operation of the compressed air source so that compressed air from the compressed air source flows into a retraction mechanism of the dimension measuring device 60. The tip of the probe 300 contacts the surface of the workpiece W due to the action of the retraction mechanism (described later). A signal based on the displacement of the probe 300 from a predetermined reference point is amplified by the differential transformer 180 and transmitted to the control device 20 by wire or wirelessly. The control device 20 accurately calculates the outer diameter of the workpiece W based on the signal received from the differential transformer 180 and displays the calculated value on the operator's work terminal 10.

[0014] 2 is a partial cross-sectional schematic view of a dimension measuring device 60 according to an embodiment. The dimension measuring device 60 includes a probe 300 that contacts the workpiece W, a long member having a first end side and a second end side, a shape changing means, a substantially rectangular parallelepiped case member 190, a retraction mechanism 100 that is a pneumatic cylinder housed therein, and a differential transformer 180.

[0015] The elongated member refers to a rod-like member extending in the longitudinal direction, and in this example, is the finger 234. Details of the finger 234 will be described later. The first end side of the elongated member refers to one end side in the longitudinal direction (the end side in the +Y-axis direction shown in FIG. 2), where the elongated member (i.e., the finger 234) supports the probe 300 at the first end side. The second end side of the elongated member refers to the other end side in the longitudinal direction (the end side in the -Y-axis direction shown in FIG. 2), where the elongated member (i.e., the finger 234) is supported by the main body of the dimension measuring device 60 so as to be swingable at the second end side. The shape changing means refers to a means for changing the cross-sectional shape of the elongated member (i.e., the finger 234). Here, the cross-sectional shape refers to the shape of a cross section taken in a direction perpendicular to the longitudinal direction of the elongated member. The cross-sectional shape may be rectangular, polygonal, circular, or elliptical. As will be described later, the shape changing means according to the present disclosure can easily change the cross-sectional shape of the elongated member.

[0016] Lever shaft 132, which is connected to gauge head 300 via finger 234, extends laterally from case member 190. Bellows 220, which enables precession of lever shaft 132, is disposed between case member 190 and lever shaft 132, and locking portions 222, 224 are formed at both ends of bellows 220. Within case member 190, pivot shaft 140 is disposed substantially perpendicular to lever shaft 132, and pivot shaft 140 is fitted into a through-hole formed in holder 142 disposed in the longitudinal middle of lever shaft 132. Therefore, lever shaft 132 can pivot around pivot shaft 140.

[0017] One side of case member 190 has an opening, and one end of bellows 220 described above is held airtight in the opening by locking portion 222. The other end of bellows 220 is airtightly connected to end 132b of lever shaft 132 by locking portion 224. End 132b of lever shaft 132 on the attachment side of bellows 220 is coupled to finger 234 via position fine adjustment device 237 so that its position can be finely adjusted.

[0018] Although omitted in FIG. 2 for convenience of explanation, the finger 234 is provided with a means for changing its natural frequency, thereby suppressing resonance of the finger 234. The position fine adjustment device 237 includes a stay 231, made of, for example, a metal, with a substantially T-shaped cross section, connected to the end 132b of the lever shaft 132; a plate-shaped elastic member 232 having an end surface contacting the end surface of the stay 231; a plate-shaped rigid member 233 sandwiching the plate-shaped elastic member 232 together with the stay 231; and a connecting member 235 having an end surface contacting the end surface of the plate-shaped rigid member 233 and connecting the opposite end surface to the end surface of the end of the finger 234. The plate-shaped elastic member 232 may be, but is not limited to, a rubber sheet. The plate-shaped rigid member 233 may be, but is not limited to, a metal, ceramic, or resin sheet. The connecting member 235 may be a rectangular parallelepiped or cylindrical member made of metal, ceramic, or rubber.

[0019] The stay 231, the plate-shaped elastic member 232, the plate-shaped rigid member 233, and the connecting member 235 have a plurality of through-holes that penetrate in the Y-axis direction and are rotationally symmetrical on the XZ plane, and the respective through-holes are aligned with one another. Therefore, the stay 231, the plate-shaped elastic member 232, the plate-shaped rigid member 233, and the connecting member 235 can be fixed to one another by inserting bolts through the through-holes and fastening them with nuts. In this way, a multi-layer structure is formed by stacking a plurality of members with different elastic moduli, and the relative position of the contactor portion 240 at the tip of the probe 300 with respect to the lever shaft 132 can be finely adjusted by adjusting the tightness of each bolt that is arranged rotationally symmetrically.

[0020] The fine position adjustment device 237 not only finely adjusts the position of the tip of the probe 300 relative to the lever shaft 132, but also has the function of adjusting distortion (warping) of the finger 234 in the longitudinal direction, as will be described later. That is, as will be described later, the fine position adjustment device 237 can finely adjust the warping of the finger 234 when a force is applied in a direction perpendicular to the longitudinal direction of the finger 234 so that there is no apparent warping. As a result, highly accurate dimensional measurements are ensured. Note that the configuration of the fine position adjustment device 237 is not limited to that described above.

[0021] A probe holder 236 for holding the probe 300 is attached to the tip of the finger 234 on the side opposite to the side connected to the lever shaft 132. By adjusting a set screw 238 that engages with the probe holder 236, the position of the contactor portion 240 at the tip of the probe 300 can be adjusted in the vertical direction in Fig. 2. When measuring the outer diameter as shown in Fig. 1, the upper contactor portion 240 of this example is pressed downward, and the lower contactor portion 240 of this example is pressed upward, thereby clamping the workpiece W and measuring the outer diameter.

[0022] The upper dimension measuring device 60 will be described below, but the lower dimension measuring device 60 has the same configuration and functions as the upper dimension measuring device 60 except that it is upside down.

[0023] To press the contact portion 240 downward, a tension spring 146 is disposed inside the case member 190 on the opposite side 132a of the lever shaft 132 from the holder 142 toward the measuring element. One end of the tension spring 146 is engaged with a support shaft 148 protruding inside the case member 190, and the other end of the tension spring 146 is engaged with a locking member 134 provided at the longitudinal middle of the lever shaft 132. Therefore, the tension spring 146 acts to attract the lever shaft 132 at that position, causing the lever shaft 132 to swing around the swing shaft 140 and then pressing the finger 234 downward. This enables measurement. The differential transformer 180, tension spring 146, and swing shaft 140 constitute a swinging means.

[0024] A displacement shaft 182 is attached perpendicular to the lever shaft 132 near the end of the lever shaft 132 on the side 132a opposite to the probe, and a coil 184 is wound around the displacement shaft 182 to form a differential transformer 180. A signal from the differential transformer 180 is input to a terminal processing unit 186, where it is processed, and then transmitted to the control device 20 (see FIG. 1).

[0025] When the measurement is completed or when preparation for the measurement is being made, the contactor portion 240 is moved away from the workpiece W to protect both the contactor portion 240 and the workpiece W. For this reason, a retraction mechanism 100, which is a pneumatic cylinder, is disposed in the longitudinal direction of the lever shaft 132, between the tension spring 146 and the differential transformer 180.

[0026] The retraction mechanism 100 includes a cap-shaped cylinder 110, a piston 120 that is slidable within the cylinder 110 and has a piston head 116 and a piston rod 118, a cylinder base 112 that is located below the cylinder 110 and in sliding contact with the lower part of the piston rod 118, and a coil spring 122 that is wound around the piston rod 118 and is disposed between the piston head 116 and the cylinder base 112. One end (upper side) of the piston rod 118 is housed within the cylinder 110, and the other end (lower side) extends downward from the cylinder base 112. An abutment portion 136 that is the lower end of the piston rod 118 can abut against a lever shaft 132.

[0027] Next, the operation of the retraction mechanism 100 will be described. During measurement, pressurized air from the compressed air source is not introduced into the space 108 formed between the cylinder 110 and the piston head 116, and the pressure in the space 108 becomes approximately the same as the pressure in the space 106 of the piston head, which is connected to the outside atmosphere (approximately atmospheric pressure). As a result, the restoring force (elastic force) of the coil spring 122 becomes dominant, and the piston rod 118 is pulled upward. At this time, the lever shaft 132, which had been in contact with the piston rod 118, rotates clockwise around the swing shaft 140 by the tension spring 146, and the probe 300, located at the tip of the finger 234 connected to the tip of the lever shaft 132, moves downward. The downward movement stops as soon as the probe 300 comes into contact with the workpiece W, and the amount of displacement between this position and the reference point is measured by the differential transformer 180, which is provided at the end of the lever shaft 132 opposite the probe 300.

[0028] On the other hand, when not measuring, pressurized air is introduced from a compressed air source into the space 108 formed between the cylinder 110 and the piston head 116, urging the coil spring 122 in the compression direction, causing the piston rod 118 to move downward against the elastic force of the coil spring 122. The abutting portion 136 of the piston rod 118 abuts against the lever shaft 132, pushing the lever shaft 132 downward and rotating counterclockwise around the swing shaft 140 in the figure, causing the probe 300 located at the tip of the finger 234 connected to the tip of the lever shaft 132 to move upward. In this way, the contact portion 240 moves away from the workpiece W. When the lever shaft 132 has rotated to a position where the force applied by the abutting portion 136 of the piston rod 118 to the lever shaft 132 and the elastic force of the tension spring 146 are balanced, the position of the probe 300 in the Z-axis direction is maintained.

[0029] <First embodiment of finger> FIG. 3 is a schematic cross-sectional view of the dimension measuring device 60 shown in FIG. 2 taken along dashed line A-A, illustrating a first embodiment of a finger. For ease of explanation, the probe 300 is shown by a dashed-dotted line. In this example, the finger 400 supports the probe 300 at the first end 402 and is connected to the main body of the dimension measuring device 60 at the second end 404 via a fine position adjustment device 237. A slit 410 is formed along the longitudinal direction inside the body 406 of the finger 400 (elongated member). In this example, the slit 410 extends along the horizontal plane along the longitudinal direction from near the first end 402 toward the second end 404. After abutting against an end face 432 on the second end 404 side facing the first end 402, the slit 410 bends downward 90° (i.e., in the -Z-axis direction) and penetrates the body 406. In other words, a gap 430 exists between the end face 432 and the body 406. Therefore, the body 406 is substantially C-shaped.

[0030] The finger 400 has a shape-changing means for changing the width of the slit 410. Here, the width of the slit 410 refers to the width of the slit 410 in a direction perpendicular to the longitudinal direction (the Z-axis direction in FIG. 3). The shape-changing means may be a threaded fastener. The threaded fastener may be a bolt or a set screw. The following describes a case where the threaded fastener is a bolt 420. A hole 414 is provided in the body 406 from the longitudinal center toward the second end 404, reaching the slit 410 and having a threaded inner surface.

[0031] As bolt 420 is inserted into hole 414 and threadedly engages with the inner surface of hole 414, the tip of bolt 420 eventually abuts against lower inner surface 412 of slit 410. Furthermore, as bolt 420 continues to be tightened, lower inner surface 412 of slit 410 is pushed in the direction of movement of bolt 420, gradually widening the width of slit 410. This causes a change in the cross-sectional shape of finger 400 (in this example, the dimensions in the longitudinal direction and the vertical direction (i.e., the Z-axis direction) increase), and the second moment of area changes. As a result, the natural frequency of finger 400 changes, making it possible to suppress resonance at the tip of probe 300.

[0032] A bolt 440 is used to connect the body 406 and the second end 404 across the gap 430. A longitudinal groove 450 is formed in the end face 432 in a direction perpendicular to the longitudinal direction, and a hole 434 with a threaded inner surface is formed in the longitudinal direction on the side of the body 406 opposite the longitudinal groove 450. The bolt 440 is inserted through a recess 460 provided in the second end 404 and threadedly engages with the hole 434 via the longitudinal groove 450 and the gap 430. The bolt 440 is restricted from moving in the vertical direction (i.e., in the Z-axis direction) by the upper and lower ends of the longitudinal groove 450, but is movable between them in the vertical direction. This maintains the connection between the body 406 and the second end 404 even if the width of the slit 410 changes.

[0033] 3, an example has been described in which the moving direction of bolt 420 is the -Z-axis direction, but the present invention is not limited to this, and the moving direction of bolt 420 may be the +Z-axis direction. Also, an example has been described in which slit 410 is formed on a horizontal plane along the longitudinal direction, but the present invention is not limited to this, and slit 410 may be formed on any plane along the longitudinal direction.

[0034] Fig. 4 is a cross-sectional view of a modified example of the first embodiment of the finger. Finger 400 of this example differs from the example shown in Fig. 3 in that the threaded fastener serving as shape changing means has an end portion that penetrates finger 400 (elongated member) and is connected to the pin, rather than a bolt 420. Threaded fastener 428 of this example has a screw portion 422, a support portion 426 having one end connected to screw portion 422 and penetrating body 406, and a pin 424 connected to the other end of support portion 426 in a direction perpendicular to the longitudinal direction (the X-axis direction in Fig. 4).

[0035] When the screw portion 422 of the threaded fixture 428 is rotated, the screw portion 422 advances in an upward direction perpendicular to the longitudinal direction (the +Z-axis direction in FIG. 4), and eventually the pin 424 comes into contact with the outer circumferential surface of the body 406. As the screw portion 422 continues to rotate, the outer circumferential surface of the body 406 is pushed in the direction of advancement of the pin 424, gradually narrowing the width of the slit 410. This causes a change in the cross-sectional shape of the finger 400 (in this example, the dimensions in the longitudinal direction and the perpendicular direction (i.e., the Z-axis direction) become smaller), and the second moment of area changes. As a result, the natural frequency of the finger 400 changes, making it possible to suppress resonance at the tip of the probe 300.

[0036] FIG. 5 is a cross-sectional view of another variation of the first embodiment of the finger. In the finger 500 of this example, the slit 410 has a narrowed portion whose width narrows continuously or stepwise, and the shape-changing means includes a width-expanding means that slides along the narrowed portion. Here, the narrowed portion whose width narrows continuously or stepwise refers to a sloped or stepped space configured so that the width of the slit 410 in the direction perpendicular to the longitudinal direction (i.e., the Z-axis direction in FIG. 5 ) narrows continuously or stepwise along the longitudinal direction. As shown in FIG. 5 , the narrowed portion 520 in this example has a wall surface 522 that extends perpendicular to the longitudinal direction (i.e., the −Z-axis direction) and faces the first end 402, and a slope 524 that slopes continuously from the bottom of the wall surface 522 to reach the lower inner surface 412 of the slit 410. As shown in FIG. 5, in this example, the narrowed portion 520 is configured so that the width of the slit gradually narrows continuously from the second end 404 side to the first end 402 side along the longitudinal direction.

[0037] The width expanding means that slides on the narrowed portion refers to a means that expands the width of slit 410 as it slides on narrowed portion 520 in the longitudinal direction. In this example, width expanding means 540 has pin 530 that slides on narrowed portion 520, support member 542 that supports pin 530, and guide member 544 that guides support member 542 along the longitudinal direction. Pin 530 has a cylindrical shape, and the diameter of its cross section is larger than the width of slit 410 and smaller than the slit width at wall surface 522 of narrowed portion 520.

[0038] When the support member 542 is guided by the guide member 544 and moved in the longitudinal direction from the second end 404 side to the first end 402 side, the pin 530 leaves the wall surface 522 and climbs the slope 524. Eventually, the pin 530 comes into contact with the upper inner surface 413 of the slit 410. As the support member 542 continues to move, the diameter of the pin 530 is larger than the width of the slit 410, so the width of the slit 410 gradually expands. This causes a change in the cross-sectional shape of the finger 500 (in this example, the dimensions in the longitudinal direction and the vertical direction (i.e., the Z-axis direction) increase), and the second moment of area changes. As a result, the natural frequency of the finger 500 changes, making it possible to suppress resonance at the tip of the probe 300.

[0039] 5, an example in which the slope 524 is continuously inclined and the pin 530 has a cylindrical shape has been described, but this is not limiting. For example, the slope 524 may be stepped, or may be a combination of a continuous slope and a step. Furthermore, the pin 530 may be a columnar body with a trapezoidal (e.g., wedge-shaped) cross section.

[0040] FIG. 6 is a cross-sectional view of a modified example of finger 500 shown in FIG. 5. In the finger of this example, the inclination direction of slope 525 of narrowed portion 521 is different from slope 524 of narrowed portion 520 of FIG. 5. In this example, narrowed portion 521 has wall surface 523 that extends perpendicular to the longitudinal direction (i.e., in the −Z-axis direction) and faces second end 404, and slope 525 that slopes continuously from the bottom of wall surface 523 to reach inner surface 412 below slit 410. As shown in FIG. 6, in this example, narrowed portion 521 is configured so that the width of the slit continuously and gradually narrows along the longitudinal direction from first end 402 to second end 404.

[0041] When the support member 542 is guided by the guide member 544 and moved in the longitudinal direction from the first end 402 side to the second end 404 side, the pin 530 leaves the wall surface 523 and climbs the slope 525. Eventually, the pin 530 comes into contact with the upper inner surface 413 of the slit 410. As the support member 542 continues to move, the diameter of the pin 530 is larger than the width of the slit 410, so the width of the slit 410 gradually expands. This causes a change in the cross-sectional shape of the finger 500 (in this example, the dimensions in the longitudinal direction and the vertical direction (i.e., the Z-axis direction) increase), and the second moment of area changes. As a result, the natural frequency of the finger 500 changes, making it possible to suppress resonance at the tip of the probe 300.

[0042] 6, an example in which the slope 525 is continuously inclined and the pin 530 has a cylindrical shape has been described, but this is not limiting. For example, the slope 525 may be stepped, or may be a combination of a continuous slope and a step. Furthermore, the pin 530 may be a columnar body with a trapezoidal (e.g., wedge-shaped) cross section.

[0043] <Second embodiment of finger> FIG. 7 is a cross-sectional view showing a second embodiment of a finger. The finger 600 (elongated member) of this embodiment has a cross-sectional structure of two or more layers along the longitudinal direction. In this embodiment, the cross-sectional structure of two or more layers refers to a cross-sectional structure perpendicular to the longitudinal direction of a two-layer finger including a first metal layer 610 extending along the longitudinal direction and a second metal layer 612 extending along the longitudinal direction coaxially with the first metal layer 610. The first metal layer 610 and the second metal layer 612 are preferably made of metal such as iron, steel, or stainless steel, but may be made of other metals. The first metal layer 610 and the second metal layer 612 may be made of the same type of metal or different types of metal. That is, the Young's modulus of the first metal layer 610 and the Young's modulus of the second metal layer 612 may be the same or different. Furthermore, the finger 600 may have a coaxial cross-sectional structure of three or more layers.

[0044] A gap 640 is provided between the first metal layer 610 and the second metal layer 612. The first metal layer 610 has an end portion 614 extending radially from a central longitudinal axis. An end surface of the second metal layer 612 on the first end 402 side is welded to an end surface of the end portion 614. As a result, the gap 640 is sealed by the end portion 614 on the first end 402 side of the finger 600.

[0045] Meanwhile, first metal layer 610 has a hole 618 with a threaded inner surface in the longitudinal direction on the second end 404 side. When bolt 632 is threaded into hole 618, head 630 of bolt 632 abuts and welds to second metal layer 612 on the second end 404 side. As a result, gap 640 is sealed by head 630 of bolt 632 on the second end 404 side of finger 600.

[0046] The finger 600 has a shape-changing means for changing the size of the gap 640 between the layers. Here, the size of the gap 640 between the layers refers to the size of the gap 640 in a direction perpendicular to the longitudinal direction (the Z-axis direction in FIG. 5 ). The shape-changing means may be a threaded fastener. The threaded fastener may be a bolt or a set screw. An example in which the threaded fastener is a bolt 620 will be described below. A hole 624 with a threaded inner surface is provided from the longitudinal center of the finger 600 toward the second end 404, penetrating the second metal layer 612 and reaching the gap 640.

[0047] As the bolt 620 is inserted into the hole 624 and threadedly engages with the inner surface of the hole 624, the tip of the bolt 620 eventually contacts the outer peripheral surface 616 of the first metal layer 610. Furthermore, as the bolt 620 continues to be tightened, the outer peripheral surface 616 of the first metal layer 610 is pressed in the direction of movement of the bolt 620, causing the first metal layer 610 to bend downward (in the -Z-axis direction) in the figure due to the pressure, and the size of the upper gap 640 gradually increases. This changes the cross-sectional shape of the finger 600 at the portion where pressure is applied by the bolt 620, changing the moment of inertia. As a result, the natural frequency of the finger 600 changes, thereby suppressing resonance at the tip of the probe 300.

[0048] In this example, the tension of the first metal layer 610 is also changed by applying local pressure to the first metal layer 610. Therefore, a synergistic effect of the resonance suppression effect due to the change in the second moment of area of ​​the finger 600 and the resonance suppression effect due to the change in tension can be expected.

[0049] Furthermore, the natural frequency can be controlled and utilized. For example, if the natural frequency of finger 600 is 100 Hz to 200 Hz, adjusting the natural frequency to a desired frequency (e.g., 150 Hz) by changing the pressure that bolt 620 applies to first metal layer 610 can pinpoint and eliminate that frequency using a filter, making it possible to almost completely eliminate the effects of resonance from the measurement results using probe 300.

[0050] 7, an example in which the moving direction of the bolt 620 is the −Z-axis direction and the bolt 620 and the hole 624 are provided closer to the second end 404 from the center in the longitudinal direction has been described, but the present invention is not limited to this. That is, the bolt 620 and the hole 624 may be provided at any position along the circumferential direction of the finger body. Furthermore, the bolt 620 and the hole 624 may be provided at any position along the longitudinal direction.

[0051] The finger 600 (long member) has a damping means for damping the vibration of the probe 300. The damping means refers to a means for quickly absorbing the vibration of the probe 300 that occurs after the natural frequency is changed by the shape changing means. By being enclosed in the gap 640, the damping means functions as a buffer for the vibration of the probe 300. Examples of the damping means include powder, fluid, viscoelastic material, solid material, and porous material (sponge).

[0052] FIG. 8 is a cross-sectional view showing a modification of the second embodiment of the finger. The finger 700 of this example differs from the finger 600 shown in FIG. 7 in that the first metal layer 710 has a hollow portion 730 and the shape changing means is an inner diameter clamp 720. The first metal layer 710 has an end portion 714 on the first end 402 side and an opening 716 on the second end 404 side. The hollow portion 730 extends inside the first metal layer 710 from the end portion 714 to the opening 716 so as to include a central axis along the longitudinal direction of the first metal layer 710. A flange portion 718 is provided at the end of the first metal layer 710 on the second end 404 side, and the end surface of the flange portion 718 facing the first end 402 is welded to the end surface of the body 406 on the second end 404 side. In this way, gap 640 is sealed in the longitudinal direction by end portion 714 on the first end 402 side and flange portion 718 on the second end 404 side. Inner diameter clamp 720 as shape changing means refers to a member having a structure in which the base portion expands when the central screw is turned.

[0053] 9A and 9B are enlarged front views of the inner diameter clamp 720 shown in FIG. 8 , viewed from the second end 404 side along the Y-axis. FIG. 9A shows the state of the inner diameter clamp 720 before expansion, and FIG. 9B shows the state of the inner diameter clamp 720 after expansion. The inner diameter clamp 720 includes a central screw hole 724 and multiple jaws 722 arranged rotationally symmetrically around the screw hole 724. When the screw hole 724 is rotated in a predetermined direction using a jig, the jaws 722 simultaneously expand radially depending on the angle of rotation, resulting in a transition from the state shown in FIG. 9A to the state shown in FIG. 9B. When the screw hole 724 is rotated in the opposite direction, the jaws 722 simultaneously contract radially depending on the angle of rotation, resulting in a transition from the state shown in FIG. 9B back to the state shown in FIG. 9A.

[0054] The inner diameter clamp 720 is inserted into the hollow portion 730 and fixed at a position closer to the second end 404 in the longitudinal direction than the center. When the screw hole 724 is rotated in a predetermined direction using a jig through the opening 716, the outer surface of the ferrule portion 722 of the inner diameter clamp 720 eventually abuts against the inner surface 712 of the hollow portion 730. As the screw hole 724 continues to rotate, the pressure of the ferrule portion 722 presses against the inner surface 712 of the hollow portion 730, gradually increasing the diameter of the first metal layer 710 and gradually reducing the size of the gap 640 around it. This changes the cross-sectional shape of the finger 700 at the portion where pressure is applied by the ferrule portion 722 of the inner diameter clamp 720, changing the moment of inertia. As a result, the natural frequency of the finger 700 changes, thereby suppressing resonance at the tip of the probe 300.

[0055] 8, an example in which the inner diameter clamp 720 is provided closer to the second end 404 from the center in the longitudinal direction has been described, but the present invention is not limited to this. That is, the inner diameter clamp 720 may be provided at any position within the hollow portion 730. Furthermore, multiple inner diameter clamps 720 may be provided within the hollow portion 730.

[0056] The finger 700 (long member) has a damping means for damping vibrations of the probe 300. By being sealed in the gap 640, the damping means functions as a buffer for vibrations of the probe 300. Examples of the damping means include powder, fluid, viscoelastic material, solid material, and porous material (sponge).

[0057] Figure 10 shows another example of a dimension measuring device. The dimension measuring device 70 of this example differs from the dimension measuring device 60 of Figure 2 in that it has a cross spring 80 instead of a retraction mechanism 100. The cross spring 80 is held in contact with an arm member 83 and a dimension measuring device main body 81 so as to be sandwiched between them, and functions as a swing fulcrum for the dimension measuring device 70. A core 86 of a differential transformer is attached to the rear end of the arm member 83, and a coil 87 of the differential transformer is attached to the dimension measuring device main body 81.

[0058] Furthermore, a compression coil spring 88 is provided between the dimension measuring device main body 81 and the arm member 83 to apply a measurement pressure to the measurement element 300, and a stopper screw 89 provided on the dimension measuring device main body 81 is configured to set the swing lower end of the arm member 83. In the dimension measuring device 70, the arm member 83 performs a seesaw motion with the cross spring 80 as the fulcrum, so that the amount of movement of the measurement element 300 when it is brought into contact with the workpiece W is detected by a differential transformer, enabling highly accurate measurements to be performed.

[0059] The above-described embodiments and modifications of the present disclosure are merely examples of the present disclosure and are not intended to limit the scope of the present disclosure. It will be appreciated by those skilled in the art that various modifications and changes can be made without departing from the spirit and scope of the present disclosure, and that these modifications and changes are also included in the scope of the present disclosure. [Explanation of symbols]

[0060] 1. Dimensional measurement system 10 Operator's workstation 20 Control device 60 Dimensional measuring device 300 Probe double work 234 Finger 300 Probe 400 fingers 402 1st end 404 2nd end 406 Body 410 Slit 414 hole 420 volts 422 screw part 424 pins 426 Support part 428 Threaded Fixtures 500 fingers 520 Stenosis 521 Stenosis 522 Wall 523 Wall 524 Slope 525 Slope 530 pins 540 Width expansion means 542 Support member 544 Guide member 600 fingers 610 1st metal layer 612 2nd metal layer 618 holes 620 volts 624 holes 640 Gap 700 fingers 710 1st metal layer 720 Inner Diameter Clamp 722 Cap part 724 screw holes 730 Hollow part

Claims

1. a measuring head that contacts the workpiece; an elongated member that supports the probe at a first end side and is swingably supported by a main body at a second end side; a shape changing means for changing the cross-sectional shape of the elongated member; A dimension measuring device comprising:

2. The elongated member has a slit along its longitudinal direction, 2. The dimension measuring device according to claim 1, wherein the shape changing means changes the width of the slit.

3. the elongated member has a cross-sectional structure of two or more layers along the longitudinal direction, 3. The dimension measuring device according to claim 2, wherein the shape changing means changes the size of the gap between layers.

4. 4. The dimension measuring device according to claim 2, wherein the shape changing means includes a threaded fastener.

5. 5. The dimension measuring device according to claim 4, wherein the threaded fastener has an end portion that passes through the elongated member and is connected to the elongated member by a pin.

6. 3. The dimension measuring device according to claim 2, wherein the slit has a narrowed portion whose width narrows continuously or stepwise, and the shape changing means includes width expanding means that slides along the narrowed portion.

7. 4. The dimension measuring device according to claim 2, wherein the long member has a damping means for damping vibration of the measuring element.

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