Measurement ball holding jig

Abstract

To provide a measurement ball holding tool that can enhance measurement accuracy of a measurement position in a three-dimensionally shaped measurement object.SOLUTION: A measurement ball holding tool has: a sphere body installation part that can contact with a part of a surface of a sphere body in a measurement ball; a ball holding-purpose magnet for keeping a state of the sphere body in contact with the sphere body installation part; a measurement object-purpose magnet that has a facing plane enabling facing a measurement object formed of a magnetic material; and a main body that has the sphere ball installation part, the ball holding-purpose magnet, and the measurement object-purpose magnet attached. The main body is located on an axial line counter-sphere body side with the sphere body installation part as a reference, and has a fulcrum contactable with the measurement object. When the fulcrum is in contact with the measurement object, the measurement object-purpose magnet is arranged in a position where momentum can act with respect to the main body in a rotation direction in which the sphere body in contact with the sphere body installation part comes close to the measurement object with the fulcrum as a center by magnetic force of the measurement object-purpose magnet acting with respect to the measurement object.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present disclosure relates to a measurement sphere holding jig capable of holding a measurement sphere having a sphere formed of a magnetic material and a reflecting mirror fixed to the surface of the sphere. [Background technology]

[0002] A three-dimensional shape measurement device for measuring the shape of a three-dimensional measurement object includes, for example, a measurement sphere, a measurement sphere holding jig for holding the measurement sphere, and a measurement device main body. The measurement sphere has a sphere formed of a magnetic material and a reflecting mirror fixed to the surface of the sphere. When measuring the shape of a measurement object with this three-dimensional shape measurement device, the measurement sphere is temporarily held by the measurement sphere holding jig so that the relative position between the measurement object and the measurement sphere does not change. Then, a laser beam is irradiated from the measurement device main body onto the reflecting mirror of the measurement sphere, and the laser beam reflected by the reflecting mirror is received by the measurement device main body. The measurement device main body is sometimes called a laser tracker.

[0003] An example of a measurement sphere holding jig is disclosed in Patent Document 1 below. This measurement sphere holding jig has a sphere mounting part that can contact part of the surface of the measurement sphere, a sphere holding magnet that keeps the measurement sphere in contact with the sphere mounting part, and a main body in which these are mounted. The main body has a cylindrical contactor that comes into contact with the object to be measured.

[0004] With this technique, the measurement sphere holder is held by hand or other means so that the contact of the measurement sphere holder jig remains in contact with the object to be measured. Next, the measurement sphere is rotated on the sphere mounting section so that the reflector of the measurement sphere faces the laser oscillator in the measurement device main body. The laser oscillator then irradiates the reflector with laser light, and the laser light reflected by the reflector is received by the photodetector in the measurement device main body. The measurement device main body determines the position of the measurement sphere based on the laser light received by the photodetector, and from this position of the measurement sphere, the position of the part of the object to be measured where the contact is in contact with the photodetector is determined. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] US Patent Application Publication No. 2004 / 0100705 Summary of the Invention [Problem to be solved by the invention]

[0006] As mentioned above, in the technology described in Patent Document 1, a measurement ball holding jig is present between the measurement ball and the object to be measured, and therefore the position measurement accuracy of the part of the object to be measured where the contact of the measurement ball holding jig is in contact decreases depending on the contact condition between the measurement ball and the sphere installation part of the measurement ball holding jig, the dimensional accuracy of the measurement ball holding jig, etc.

[0007] Therefore, an object of the present disclosure is to provide a measurement sphere holding jig that can improve the measurement accuracy of a measurement position in a measurement object having a three-dimensional shape. [Means for solving the problem]

[0008] In order to achieve the above object, a measurement ball holding jig according to one aspect of the invention comprises: A measurement sphere holding jig capable of holding a measurement sphere having a sphere of radius r made of a magnetic material and a reflecting mirror fixed to the surface of the sphere includes a sphere mounting portion capable of contacting a portion of the surface of the sphere, a sphere holding magnet for maintaining the sphere in contact with the sphere mounting portion, a measurement object magnet having a facing surface made of a magnetic material capable of facing the measurement object, and a main body to which the sphere mounting portion, the sphere holding magnet, and the measurement object magnet are attached. The sphere mounting portion has a seat central axis and is formed so that the center of the sphere in contact with the sphere mounting portion is located on the seat central axis. The sphere holding magnet is located on the seat central axis, on the anti-axial sphere side, opposite the sphere in contact with the sphere mounting portion, of the axial sphere side and the anti-axial sphere side in the axial direction of the seat central axis. The main body is located on the opposite side of the axis from the sphere mounting section and has a fulcrum that can come into contact with the measurement object. The fulcrum serves as the center of rotation when the main body rotates around an axis perpendicular to an imaginary plane including the seat central axis when in contact with the measurement object. The measurement object magnet is positioned so that, when the fulcrum is in contact with the measurement object, a moment can act on the main body around the fulcrum in a rotation direction in which the sphere in contact with the sphere mounting section approaches the measurement object due to the magnetic force of the measurement object magnet acting on the measurement object.

[0009] When measuring a measurement position in a measurement object using the measurement sphere holding jig of this embodiment, first, the measurement sphere is brought into contact with the sphere mounting portion of the measurement sphere holding jig. The sphere is maintained in contact with the sphere mounting portion due to the magnetic force of the sphere holding magnet. In other words, the measurement sphere is held by the measurement sphere holding jig. Next, the measurement sphere holding jig is positioned so that a portion of the body of the measurement sphere holding jig facing the area surrounding the measurement position in the measurement object is positioned. As a result, the magnetic force of the measurement object magnet causes the fulcrum of the measurement sphere holding jig to contact the area surrounding the measurement position in the measurement object, and the measurement sphere holding jig is attached around the measurement position in the measurement object. Furthermore, the magnetic force of the measurement object magnet causes a moment to act on the body around the fulcrum in a rotational direction such that the sphere in contact with the sphere mounting portion approaches the measurement object. As a result, the sphere in contact with the sphere mounting portion comes into contact with the measurement position in the measurement object.

[0010] Next, the sphere is rotated while maintaining contact with the sphere placement section and the measurement position in the object to be measured so that the reflecting mirror on the surface of the sphere faces the measurement device body.

[0011] Next, a laser beam is emitted from a laser oscillator in the measurement device body onto a reflecting mirror, and the laser beam reflected by the reflecting mirror is received by a photoreceiver in the measurement device body. The measurement device body determines the coordinates of the center of the measurement sphere based on the laser beam emitted onto the reflecting mirror and the laser beam received by the photoreceiver. Furthermore, the measurement device body uses the radius r of the sphere from the coordinates of the center of the measurement sphere to determine the coordinates of the measurement position of the measurement object with which the sphere is in contact.

[0012] In the technology described in Patent Document 1 above, explained in the background technology section, a measurement ball holding jig is present between the measurement ball and the object to be measured, so the position measurement accuracy of the part of the object to be measured where the contact of the measurement ball holding jig is in contact decreases depending on the contact condition between the measurement ball and the sphere installation part of the measurement ball holding jig, the dimensional accuracy of the measurement ball holding jig, etc.

[0013] On the other hand, in this embodiment, by bringing the measurement sphere holding jig that holds the measurement sphere into contact with the object to be measured, the sphere of the measurement sphere comes into contact with the measurement position in the object to be measured. Therefore, the measurement position determined by the measurement device main body is less affected by the contact state between the measurement sphere and the sphere installation part of the measurement sphere holding jig, the dimensional accuracy of the measurement sphere holding jig, etc. Therefore, by using the measurement sphere holding jig of this embodiment, measurement accuracy can be improved. [Effects of the Invention]

[0014] According to one aspect of the present disclosure, it is possible to improve the measurement accuracy of a measurement position in a measurement object having a three-dimensional shape. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view of a measurement object and a three-dimensional shape measurement device according to a first embodiment of the present disclosure. FIG. [Figure 2] FIG. 1 is a perspective view of a measurement ball holding jig in a first embodiment according to the present disclosure. [Figure 3] FIG. 2 is a front view of the measurement ball holding jig in the first embodiment according to the present disclosure. [Figure 4] FIG. 2 is a cross-sectional view of a measurement ball holding jig in the first embodiment according to the present disclosure. [Figure 5] FIG. 10 is a cross-sectional view of a measurement ball holding jig in a modified example of the first embodiment according to the present disclosure. [Figure 6] FIG. 10 is a perspective view of a measurement object in a second embodiment according to the present disclosure. [Figure 7] FIG. 10 is a perspective view of a measurement ball holding jig in a second embodiment according to the present disclosure. [Figure 8] FIG. 10 is a front view of a measurement ball holding jig in a second embodiment according to the present disclosure. [Figure 9] FIG. 10 is a cross-sectional view of a measurement ball holding jig in a second embodiment according to the present disclosure. [Figure 10] FIG. 10 is a perspective view of a measurement object in a third embodiment according to the present disclosure. [Figure 11] FIG. 10 is a perspective view of a measurement ball holding jig in a third embodiment according to the present disclosure. [Figure 12] FIG. 11 is a front view of a measurement ball holding jig in a third embodiment according to the present disclosure. [Figure 13] FIG. 10 is a cross-sectional view of a measurement ball holding jig in a third embodiment according to the present disclosure. [Figure 14] FIG. 10 is a perspective view of a measurement object in a fourth embodiment according to the present disclosure. [Figure 15] FIG. 10 is a perspective view of a measurement ball holding jig in a fourth embodiment according to the present disclosure. [Figure 16] FIG. 10 is a cross-sectional view of a measurement ball holding jig in a fourth embodiment according to the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, several embodiments of a measurement ball holding jig according to the present disclosure will be described in detail with reference to the drawings.

[0017] "First embodiment" A first embodiment of a measurement ball holding jig will be described with reference to FIGS.

[0018] As shown in FIG. 1, a three-dimensional shape measurement device for measuring the shape of a three-dimensional measurement object 50 includes a measurement sphere 1, a measurement device main body 5, and a measurement sphere holding jig 10 for holding the measurement sphere 1. The measurement sphere 1 has a sphere 2 made of a magnetic material and a reflecting mirror 3 fixed to the surface of the sphere 2. The measurement sphere holding jig 10 can hold the measurement sphere 1. The measurement device main body 5 can emit and receive laser light. For this reason, the measurement device main body 5 is sometimes called a laser tracker. When measuring the shape of the measurement object 50 using this three-dimensional shape measurement device, the measurement sphere 1 is first temporarily held by the measurement sphere holding jig 10. Next, the measurement sphere holding jig 10 is brought into contact with the measurement object 50 so that the relative position between the measurement object 50 and the measurement sphere 1 does not change. Then, the measurement device main body 5 irradiates a laser beam onto the reflecting mirror 3 of the measurement sphere 1, and the measurement device main body 5 receives the laser beam reflected by the reflecting mirror 3.

[0019] Here, the measurement object 50 is a fin extending in the circumferential direction Oc with the symmetric axis O as the reference. The fin as the measurement object 50 has a first surface 51 facing a first axial side Od1 and a second surface 52 facing a second axial side Od2, on both sides in the symmetric axis direction Od along which the symmetric axis O extends. The first surface 51 is a surface that is perpendicular to the symmetric axis O and extends in the circumferential direction Oc. The second surface 52 is a surface that is inclined with respect to the symmetric axis O and extends in the circumferential direction Oc. The first surface 51 and the second surface 52 intersect with each other at a position radially inward with respect to the symmetric axis O. The portion where the first surface 51 and the second surface 52 intersect is a tip 53 of the fin. The tip 53 extends in the circumferential direction Oc. In this embodiment, multiple positions (measurement positions 55) of the tip 53 extending in the circumferential direction Oc are measured.

[0020] The measurement sphere holding jig 10 in this embodiment is a jig suitable for holding the measurement sphere 1 so that the relative position of the measurement sphere 1 with respect to the measurement object 50 described above does not change. The radius of the sphere 2 of the measurement sphere 1 is r.

[0021] As shown in Figures 2 to 4, the measurement sphere holding jig 10 in this embodiment has a sphere mounting portion 11 that can contact a portion of the surface of the sphere 2, a sphere holding magnet 12 that is formed of a magnetic material and keeps the sphere 2 in contact with the sphere mounting portion 11, a measurement object magnet 15 that has an opposing surface 16 that can face the measurement object 50 that is also formed of a magnetic material, and a main body 20 to which these are attached.

[0022] As shown in FIG. 2, the sphere mounting portion 11 has a seat central axis S, and is formed so that the center C of the sphere 2 in contact with the sphere mounting portion 11 is located on the seat central axis S. Specifically, the surface shape of the sphere mounting portion 11 is a part of a sphere with a radius r and a center at a point on the seat central axis S. In this embodiment, the surface shape of the sphere mounting portion 11 is a part of a sphere, but the surface shape of the sphere mounting portion may also be a part of a cone, that is, a tapered surface. A sphere mounting portion with a tapered surface shape is easier to process during production than a sphere mounting portion 11 with a part of a sphere surface shape.

[0023] Here, the direction in which the seat central axis S extends is defined as the axial direction Sd. One side of this axial direction Sd is defined as the axial spherical side Sdd, and the other side of this axial direction Sd is defined as the axial anti-spherical side Sda. Furthermore, the direction parallel to the first imaginary plane P1 including the seat central axis S and perpendicular to the seat central axis S is defined as the axial vertical direction Sv. The side of this axial vertical direction Sv that approaches the seat central axis S is defined as the central axis side Svd, and the side of this axial vertical direction Sv that moves away from the seat central axis S is defined as the anti-central axis side Sva.

[0024] When the sphere 2 is in contact with the sphere mounting portion 11, the sphere 2 is located on the axial sphere side Sdd with respect to the sphere mounting portion 11. The sphere holding magnet 12 is located on the seat center axis S and on the axial anti-sphere side Sda with respect to the sphere mounting portion 11.

[0025] The main body 20 has a main body 21 in which the sphere mounting portion 11 and the sphere holding magnet 12 described above are provided, and a first arm 26x and a second arm 26y extending from the main body 21 in the axial perpendicular direction Sv.

[0026] The main body 21 has a front surface 22 facing the axis-spherical side Sdd, a back surface 23 facing the axis-counter-sphere side Sda, and a pair of side surfaces 24 facing each other in the axis-perpendicular direction Sv. The sphere installation section 11 is formed so as to be recessed from the front surface 22 of the main body 21 toward the axis-counter-sphere side Sda. The back surface 23 is back-to-back with respect to the front surface 22. The pair of side surfaces 24 connect the front surface 22 and the back surface 23. The distance between the pair of side surfaces 24 gradually narrows from the axis-counter-sphere side Sda toward the axis-spherical side Sdd. In other words, each side surface 24 is inclined with respect to the seat central axis S so as to gradually approach the seat central axis S from the axis-counter-sphere side Sda toward the axis-spherical side Sdd. The angle between one of the pair of side surfaces 24 and the back surface 23 forms a fulcrum 25 that can come into contact with the measurement object 50. In addition, the corner between the other of the pair of side surfaces 24 and the back surface 23 also forms a fulcrum 25 that can come into contact with the measurement target 50. The fulcrum 25 is located on the anti-sphere side Sda of the axis with respect to the sphere installation part 11, at a location away from the seat central axis S in the axis perpendicular direction Sv. In this embodiment, the fulcrum distance D, which is the distance from the seat central axis S to the fulcrum 25 in the axis perpendicular direction Sv, is less than the radius r (see FIG. 4). This fulcrum 25 serves as the center of rotation when the main body 20 rotates around an axis perpendicular to the first imaginary plane P1.

[0027] 2 and 3, the first arm 26x extends from the main body 21 to one side in the axial perpendicular direction Sv. The second arm 26y extends from the main body 21 to the other side in the axial perpendicular direction Sv. The first arm 26x and the second arm 26y both have opposing surfaces 27 that can face the first surface 51 or the second surface 52 of the measurement object 50 when the side surface 24 of the main body 21 faces the tip 53 of the measurement object 50. The opposing surfaces 27 of the first arm 26x and the second arm 26y are both located on a first imaginary plane P1.

[0028] The measurement target magnet 15 is arranged on the first arm 26x so that the facing surface 27 of the first arm 26x and the facing surface 16 of the measurement target magnet 15 are flush with each other. The measurement target magnet 15 is arranged on the second arm 26y so that the facing surface 27 of the second arm 26y and the facing surface 16 of the measurement target magnet 15 are flush with each other. Therefore, each measurement target magnet 15 is arranged so that the facing surface 16 of the measurement target magnet 15 is parallel to the seat center axis S with an interval in the axial perpendicular direction Sv and is located on the first imaginary plane P1.

[0029] 4, the object magnet 15 is positioned such that when the fulcrum 25 is in contact with the tip 53 of the object 50, the magnetic force of the object magnet 15 acting on the object 50 causes a moment M to act on the main body 20 in a rotational direction around the fulcrum 25 such that the sphere 2 in contact with the sphere installation section 11 approaches the tip 53 of the object 50. Specifically, the object magnet 15 is positioned closer to the sphere axis Sdd than the fulcrum 25 in the axial direction Sd, and on the side where the fulcrum 25 is located in the axial perpendicular direction Sv with respect to the seat center axis S. Furthermore, a portion of the opposing surface 16 of the object magnet 15 exists in an area where the distance from the seat center axis S in the axial perpendicular direction Sv is less than the fulcrum distance D, and the remaining portion of the object magnet 15 exists in an area where the distance from the seat center axis S in the axial perpendicular direction Sv is equal to or greater than the fulcrum distance D.

[0030] When measuring multiple positions on the tip 53 of the measurement target 50 using the measurement sphere holding jig 10 of this embodiment, first, the sphere 2 of the measurement sphere 1 is brought into contact with the sphere installation portion 11 of the measurement sphere holding jig 10. The sphere 2 is maintained in contact with the sphere installation portion 11 by the magnetic force of the sphere holding magnet 12. In other words, the measurement sphere 1 is held by the measurement sphere holding jig 10. Next, the measurement sphere holding jig 10 is positioned so that one side surface 24 of the main body 21 of the measurement sphere holding jig 10 holding the measurement sphere 1 faces the tip 53 of the measurement target 50 in the axis perpendicular direction Sv, and so that the facing surface 16 of one measurement target magnet 15 and the facing surface 27 of one arm 26x of the measurement sphere holding jig 10 face the first surface 51 of the measurement target 50 (see FIG. 3 ). As a result, due to the magnetic force of the measurement object magnet 15, the facing surface 16 of the measurement object magnet 15 and the facing surface 27 of one arm 26x come into contact with the first surface 51 of the measurement object 50, and the fulcrum 25 of the measurement sphere holding jig 10 comes into contact with the tip 53 of the measurement object 50. In other words, the measurement sphere holding jig 10 is attached around the tip 53 of the measurement object 50. Note that the facing surface 16 of the measurement object magnet 15 does not need to come into contact with the first surface 51 of the measurement object 50. Furthermore, due to the magnetic force of the measurement object magnet 15, specifically, the magnetic force of a portion of the measurement object magnet 15 located closer to the central axis Svd in the axial perpendicular direction Sv than the tip 53 of the measurement object 50, a moment M acts on the main body 20 around the fulcrum 25 of the measurement sphere holding jig 10 in a rotational direction such that the sphere 2 in contact with the sphere installation portion 11 approaches the tip 53 of the measurement object 50. Therefore, the sphere 2 in contact with the sphere installation portion 11 comes into contact with the tip 53 including the measurement position 55 in the measurement object 50 .

[0031] Next, the sphere 2 is rotated while maintaining contact with the sphere installation section 11 and the measurement position 55 in the object to be measured 50 so that the reflector 3 on the surface of the sphere 2 faces the side of the measurement device main body 5.

[0032] Next, a laser beam is irradiated from a laser oscillator in the measurement device main body 5 onto the reflecting mirror 3, and the laser beam reflected by the reflecting mirror 3 is received by a photoreceiver in the measurement device main body 5 (see Figure 1). The measurement device main body 5 determines the coordinates of the center C of the measurement sphere 1 based on the laser beam irradiated onto the reflecting mirror 3 and the laser beam received by the photoreceiver. Furthermore, the measurement device main body 5 uses the radius r of the sphere 2 from the coordinates of the center C of the measurement sphere 1 to determine the coordinates of the measurement position 55 of the measurement object 50 with which the sphere 2 is in contact.

[0033] In the technology described in Patent Document 1 above, explained in the background technology section, a measurement ball holding jig is present between the measurement ball and the object to be measured, so the position measurement accuracy of the part of the object to be measured where the contact of the measurement ball holding jig is in contact decreases depending on the contact condition between the measurement ball and the sphere installation part of the measurement ball holding jig, the dimensional accuracy of the measurement ball holding jig, etc.

[0034] On the other hand, in this embodiment, by bringing the measurement sphere holding jig 10 holding the measurement sphere 1 into contact with the measurement object 50, the sphere 2 of the measurement sphere 1 comes into contact with the measurement position 55 in the measurement object 50. For this reason, in this embodiment, the measurement position 55 determined by the measurement device main body 5 is less susceptible to the contact state between the measurement sphere 1 and the sphere installation portion 11 of the measurement sphere holding jig 10, the dimensional accuracy of the measurement sphere holding jig 10, etc. Therefore, by using the measurement sphere holding jig 10 in this embodiment, the measurement accuracy of the measurement position 55 can be improved.

[0035] In the measurement sphere holding jig 10 of this embodiment, as shown in FIG. 4, the fulcrum distance D, which is the distance from the seat central axis S to the fulcrum 25 in the axis-perpendicular direction Sv, is less than the radius r of the sphere 2. However, as shown in a modified example in FIG. 5, the fulcrum distance D, which is the distance from the seat central axis S to the fulcrum 25 in the axis-perpendicular direction Sv, may be equal to or greater than the radius r of the sphere 2. In this modified example, the amount of tilt of the main body 20 about the fulcrum 25 is greater than in this embodiment, and the laser beam receiving angle LA is therefore smaller than the laser beam receiving angle LA in this embodiment. In other words, in this modified example, the area in which the measurement device main body 5 that emits the laser beam can be arranged is narrower than in this embodiment. Therefore, it is preferable that the fulcrum distance D be less than the radius r of the sphere 2. However, if the fulcrum distance D is too short, the sphere holding magnet 12 and the measurement object magnet 15 will interfere with each other, so it is preferable that the fulcrum distance D is less than the radius r of the sphere 2 and greater than or equal to 1 / 2 of this radius r (r>D≧r / 2).

[0036] Second Embodiment A second embodiment of the measurement ball holding jig will be described with reference to FIGS.

[0037] As shown in FIG. 6 , a measurement object 50a whose shape and the like are measured using the measurement sphere holding jig of this embodiment is a member having an inner circumferential surface 53a extending in a circumferential direction Oc based on the symmetry axis O. The inner circumferential surface 53a has a predetermined width in the symmetry axis direction Od, in which the symmetry axis O extends. The member has the inner circumferential surface 53a, a first surface 51a connected to an edge of the inner circumferential surface 53a on the first axial side Od1 and facing the first axial side Od1, and a second surface 52a connected to an edge of the inner circumferential surface 53a on the second axial side Od2 and facing the second axial side Od2. In this embodiment, multiple positions (measurement positions 55) on the inner circumferential surface 53a are measured.

[0038] As shown in FIGS. 7 to 9, the measurement sphere holding jig 10a in this embodiment is a jig suitable for holding the measurement sphere 1 so that the relative position of the measurement sphere 1 with respect to the measurement object 50a described above does not change.

[0039] Like the measurement sphere holding jig 10 in the first embodiment, the measurement sphere holding jig 10a in this embodiment also has a sphere mounting portion 11 that can contact a portion of the surface of the sphere 2, a sphere holding magnet 12 that maintains the sphere 2, which is made of a magnetic material, in contact with the sphere mounting portion 11, a measurement object magnet 15 that has an opposing surface 16 that can face the measurement object 50a, which is made of a magnetic material, and a main body 20a to which these are attached.

[0040] As shown in FIG. 7, the sphere mounting portion 11 has a seat central axis S, and is formed so that the center C of the sphere 2 in contact with the sphere mounting portion 11 is positioned on the seat central axis S.

[0041] The main body 20a, like the main body 20 of the measurement sphere holding jig 10a in the first embodiment, has a main body 21a in which a sphere mounting portion 11 and a sphere holding magnet 12 are provided, and a first arm 26xa and a second arm 26ya extending from this main body 21a in the axial perpendicular direction Sv.

[0042] Like the main body 21 of the measurement sphere holding jig 10a in the first embodiment, the main body 21a has a front surface 22 facing the axis sphere side Sdd, a back surface 23 facing the axis counter-sphere side Sda, and a pair of side surfaces 24 facing each other in the axis perpendicular direction Sv. The sphere installation portion 11 is formed so as to be recessed from the front surface 22 of the main body 21a toward the axis counter-sphere side Sda. The back surface 23 is back-to-back with respect to the front surface 22. The pair of side surfaces 24 connect the front surface 22 and the back surface 23. The distance between the pair of side surfaces 24 gradually narrows from the axis counter-sphere side Sda toward the axis sphere side Sdd. In other words, each side surface 24 is inclined with respect to the seat central axis S so as to gradually approach the seat central axis S from the axis counter-sphere side Sda toward the axis sphere side Sdd. The angle between one of the pair of side surfaces 24 and the back surface 23 forms a fulcrum 25 that can come into contact with the measurement object 50a. The angle between the other of the pair of side surfaces 24 and the back surface 23 also forms a fulcrum 25 that can come into contact with the measurement object 50a. The fulcrum 25 is located on the anti-sphere side Sda of the axis with respect to the sphere installation part 11, at a position away from the seat central axis S in the axis perpendicular direction Sv. In this embodiment, the fulcrum distance D, which is the distance from the seat central axis S to the fulcrum 25 in the axis perpendicular direction Sv, is equal to or greater than the radius r (see FIG. 9 ). This fulcrum 25 serves as the center of rotation when the main body 20a rotates around an axis perpendicular to the first imaginary plane P1.

[0043] 7 and 8, the first arm 26xa extends from the main body 21a to one side in the axial perpendicular direction Sv. The second arm 26ya extends from the main body 21a to the other side in the axial perpendicular direction Sv. The first arm 26xa and the second arm 26ya both have opposing surfaces 27 that can face the first surface 51a or the second surface 52a of the measurement object 50a when the side surface 24 of the main body 21a faces the inner circumferential surface 53a of the measurement object 50a. The opposing surfaces 27 of the first arm 26xa and the second arm 26ya are both spaced apart from the first imaginary plane P1 in a direction perpendicular to the first imaginary plane P1.

[0044] The measurement target magnet 15 is disposed on the first arm 26xa so that the facing surface 27 of the first arm 26xa and the facing surface 16 of the measurement target magnet 15 are parallel. The measurement target magnet 15 is disposed on the second arm 26ya so that the facing surface 27 of the second arm 26ya and the facing surface 16 of the measurement target magnet 15 are parallel. Therefore, each measurement target magnet 15 is disposed so that the facing surface 16 of the measurement target magnet 15 is parallel to the seat center axis S with a gap in the axial perpendicular direction Sv and is spaced apart from the first imaginary plane P1.

[0045] 9, similar to the magnet 15 for the measurement object of the measurement sphere holding jig 10 in the first embodiment, when the fulcrum 25 is in contact with the inner peripheral surface 53a of the object to be measured 50a, the magnetic force of the magnet 15 for the measurement object acting on the object to be measured 50a causes a moment M to act on the main body 20a in a rotational direction around the fulcrum 25 such that the sphere 2 in contact with the sphere installation section 11 approaches the inner peripheral surface 53a of the object to be measured 50a. Specifically, the magnet 15 for the measurement object is disposed on the axial sphere side Sdd of the fulcrum 25 in the axial direction Sd, and on the side where the fulcrum 25 is located with respect to the seat central axis S in the axial direction Sv perpendicular to the axial line. Furthermore, a portion of the opposing surface 16 of the measurement object magnet 15 is located within an area where the distance from the seat center axis S in the axial direction Sv perpendicular to the axis is less than the aforementioned fulcrum distance D, and the remaining portion of the measurement object magnet 15 is located within an area where the distance from the seat center axis S in the axial direction Sv perpendicular to the axis is equal to or greater than the aforementioned fulcrum distance D.

[0046] When using the measurement sphere holding jig 10a of this embodiment to measure multiple positions on the inner peripheral surface 53a of the measurement target 50a, first, the sphere 2 of the measurement sphere 1 is brought into contact with the sphere mounting portion 11 of the measurement sphere holding jig 10a. The sphere 2 is maintained in contact with the sphere mounting portion 11 by the magnetic force of the sphere holding magnet 12. Next, the measurement sphere holding jig 10a is positioned so that one side surface 24 of the main body 21a of the measurement sphere holding jig 10a, which holds the measurement sphere 1, faces the inner peripheral surface 53a of the measurement target 50a in the axis perpendicular direction Sv, and so that the facing surface 16 of the measurement target magnet 15 and the facing surface 27 of the arm 26xa of the measurement sphere holding jig 10a face the first surface 51a or the second surface 52a of the measurement target 50a (see FIG. 8). As a result, due to the magnetic force of the measurement object magnet 15, the opposing surface 27 of the arm 26xa of the measurement sphere holding jig 10a contacts the first surface 51a or the second surface 52a of the measurement object 50a, and the fulcrum 25 of the measurement sphere holding jig 10a contacts the inner circumferential surface 53a of the measurement object 50a. In other words, the measurement sphere holding jig 10a is attached around the inner circumferential surface 53a of the measurement object 50a. Furthermore, due to the magnetic force of the measurement object magnet 15, specifically, the magnetic force of the portion of the measurement object magnet 15 located closer to the central axis Svd in the axially perpendicular direction Sv than the inner circumferential surface 53a of the measurement object 50a, a moment M acts on the main body 20a in a rotational direction around the fulcrum 25 of the measurement sphere holding jig 10a, in which the sphere 2 in contact with the sphere installation portion 11 approaches the inner circumferential surface 53a of the measurement object 50a. Therefore, the sphere 2 in contact with the sphere installation portion 11 comes into contact with the inner circumferential surface 53a including the measurement position 55 in the measurement object 50a.

[0047] Therefore, by using the measurement ball holding jig 10a in this embodiment, the measurement accuracy of the measurement position 55 can be improved, similar to the case where the measurement ball holding jig 10 in the first embodiment is used.

[0048] "Third embodiment" A third embodiment of the measurement ball holding jig will be described with reference to FIGS.

[0049] As shown in FIG. 10 , a measurement object 50b whose shape and the like are measured using the measurement sphere holding jig of this embodiment is a fin extending in the circumferential direction Oc around the target axis O. This fin has an inner circumferential surface 53b extending in the circumferential direction Oc around the target axis O, a first surface 51b connected to the edge of the inner circumferential surface 53b on the first axial side Od1 and facing the first axial side Od1, and a second surface 52b connected to the edge of the inner circumferential surface 53b on the second axial side Od2 and facing the second axial side Od2. The inner circumferential surface 53b of this fin is the tip of this fin. However, unlike the fin tip 53 of the measurement object 50 described with reference to FIG. 1 , the tip of this fin has a width in the target axial direction Od. In this embodiment, multiple positions (measurement positions 55) on this inner circumferential surface 53b are measured.

[0050] As shown in FIGS. 11 to 13, the measurement sphere holding jig 10b in this embodiment is a jig suitable for holding the measurement sphere 1 so that the relative position of the measurement sphere 1 with respect to the measurement object 50b described above does not change.

[0051] Like the measurement sphere holding jigs 10 and 10a in the first and second embodiments, the measurement sphere holding jig 10b in this embodiment also has a sphere mounting portion 11 that can contact a portion of the surface of the sphere 2, a sphere holding magnet 12 that is made of a magnetic material and that maintains the sphere 2 in contact with the sphere mounting portion 11, a measurement object magnet 15b that has an opposing surface 16b that can face the measurement object 50b that is made of a magnetic material, and a main body 20b to which these are attached, as shown in Figures 11 to 13.

[0052] As shown in FIG. 11, the sphere mounting portion 11 has a seat central axis S, and is formed so that the center C of the sphere 2 in contact with the sphere mounting portion 11 is positioned on the seat central axis S.

[0053] The main body 20b has a main body 21b on which the sphere mounting portion 11 and the sphere holding magnet 12 are provided, and a fulcrum body 26b extending from the main body 21b on the axis opposite the sphere side Sda.

[0054] The main body 21b has a front surface 22 facing the axial spherical side Sdd, a back surface 23 facing the axial anti-spherical side Sda, and a pair of side surfaces 24 facing each other in the axial perpendicular direction Sv. The sphere installation portion 11 is formed so as to be recessed from the front surface 22 of the main body 21b toward the axial anti-spherical side Sda. The back surface 23 is in a back-to-back relationship with the front surface 22. The pair of side surfaces 24 connect the front surface 22 and the back surface 23.

[0055] The fulcrum body 26b has a substantially rectangular parallelepiped shape, and its surface facing the axis sphere side Sdd is connected to the back surface 23 of the main body 21b. The fulcrum body 26b has a pair of side surfaces 28b facing each other in the axis perpendicular direction Sv and a back surface 27b facing the axis anti-sphere side Sda. The edge of the pair of side surfaces 28b on the axis anti-sphere side Sda is connected to the back surface 27b. One of the pair of side surfaces 28b is flush with one of the side surfaces 24 of the main body 21b. The main body 20b has a first groove 29ba recessed from one of the side surfaces 24 of the main body 21b and one of the side surfaces 28b of the fulcrum body 26b toward the central axis side Svd and extending in the axial direction Sd. The main body 20b further has a second groove 29bb recessed from the bottom of the first groove 29ba toward the central axis side Svd and extending in the axial direction Sd. The groove width of the first groove 29ba and the groove width of the second groove 29bb are both wider than the distance between the first surface 51b and the second surface 52b of the measurement object 50b (see FIG. 12). Therefore, the tip portion of the measurement object 50b, including the inner circumferential surface 53b, can fit into the second groove 29bb. The first groove 29ba and the second groove 29bb both extend from the front surface 22 of the main body 21b to the back surface 27b of the fulcrum body 26b.

[0056] 13, the angle between the bottom surface of second groove 29bb and back surface 27b of fulcrum body 26b forms fulcrum 25b that can come into contact with inner circumferential surface 53b of measurement object 50b. Therefore, fulcrum 25b is located at a position away from seat center axis S in the axis perpendicular direction Sv on the anti-sphere side Sda with respect to the axis of sphere installation part 11. In this embodiment, fulcrum distance D, which is the distance from seat center axis S to fulcrum 25b in the axis perpendicular direction Sv, is less than radius r.

[0057] The magnet 15b for the measurement object is positioned so that when the fulcrum 25b is in contact with the inner surface 53b of the object to be measured 50b, the magnetic force of the magnet 15b for the measurement object acting on the object to be measured 50b causes a moment M to act on the main body 20b in a rotational direction around the fulcrum 25b, in which the sphere 2 in contact with the sphere installation section 11 approaches the inner surface 53b of the object to be measured 50b.

[0058] Specifically, the measurement object magnet 15b is arranged in the fulcrum body 26b as follows. (1) All of the measurement object magnets 15b are located within an area whose distance from the seat central axis S is less than the fulcrum distance D. Therefore, all of the opposing surfaces 16b of the measurement object magnets 15b are located within an area whose distance from the seat central axis S is less than the fulcrum distance D. (2) The opposing surface 16b of the measurement object magnet 15b is flush with the bottom surface of the second groove 29bb or is closer to the seat center axis S than the bottom surface of the second groove 29bb. (3) Opposing surface 16b of measurement object magnet 15b is parallel to second imaginary plane P2 and is spaced from second imaginary plane P2 on the side opposite to the central axis Sva. The second imaginary plane P2 is an imaginary plane that includes the seat central axis S and is perpendicular to the first imaginary plane P1. Therefore, the second imaginary plane P2 is perpendicular to the axis perpendicular direction Sv (see FIG. 12). (4) The facing surface 16b of the measurement object magnet 15b intersects perpendicularly with the first imaginary plane P1.

[0059] When using the measurement sphere holding jig 10b of this embodiment to measure multiple positions on the inner peripheral surface 53b of the measurement target 50b, first, the sphere 2 of the measurement sphere 1 is brought into contact with the sphere mounting portion 11 of the measurement sphere holding jig 10b. The sphere 2 is maintained in contact with the sphere mounting portion 11 by the magnetic force of the sphere holding magnet 12. Next, the tip portion of the measurement target 50b, including the inner peripheral surface 53b, is inserted into the second groove 29bb of the measurement sphere holding jig 10b that holds the measurement sphere 1, and the measurement sphere holding jig 10b is positioned so that the bottom surface of the second groove 29bb and the opposing surface 16b of the measurement target magnet 15b face the inner peripheral surface 53b of the measurement target 50b in the axis perpendicular direction Sv (see FIG. 12). As a result, the magnetic force of the measurement object magnet 15b causes the fulcrum 25b of the measurement sphere holding jig 10b to come into contact with the inner circumferential surface 53b of the measurement object 50b, and the measurement sphere holding jig 10b becomes attached around the inner circumferential surface 53b, including the measurement position 55 in the measurement object 50b. Furthermore, the magnetic force of the measurement object magnet 15b causes a moment M to act on the main body 20b in a rotational direction around the fulcrum 25b of the measurement sphere holding jig 10b, such that the sphere 2 in contact with the sphere installation part 11 approaches the inner circumferential surface 53b of the measurement object 50b. Therefore, the sphere 2 in contact with the sphere installation part 11 comes into contact with the inner circumferential surface 53b at the measurement position 55 in the measurement object 50b.

[0060] Therefore, by using the measurement ball holding jig 10b in this embodiment, the measurement accuracy of the measurement position 55 can be improved, similar to the case where the measurement ball holding jig 10, 10a in each of the embodiments described above is used.

[0061] "Fourth Embodiment" A third embodiment of the measurement ball holding jig will be described with reference to FIGS.

[0062] 14, a measurement object 50c whose shape, etc., is measured using the measurement sphere holding jig of this embodiment is a member having a smooth curved surface or a flat surface (hereinafter, these surfaces are collectively referred to as measurement surface 53c). In this embodiment, a plurality of positions (measurement positions 55) on this measurement surface 53c are measured.

[0063] As shown in FIGS. 15 and 16, the measurement sphere holding jig 10c in this embodiment is a jig suitable for holding the measurement sphere 1 so that the relative position of the measurement sphere 1 with respect to the measurement object 50c does not change.

[0064] Like the measurement sphere holding jigs 10, 10a, and 10b in the above embodiments, the measurement sphere holding jig 10c in this embodiment also has a sphere mounting portion 11 that can contact a portion of the surface of the sphere 2, a sphere holding magnet 12 formed of a magnetic material for maintaining the sphere 2 in contact with the sphere mounting portion 11, a measurement object magnet 15c having an opposing surface 16c that can face the measurement object 50c formed of a magnetic material, and a main body 20c to which these are attached.

[0065] As shown in FIG. 15, the sphere mounting portion 11 has a seat central axis S, and is formed so that the center C of the sphere 2 in contact with the sphere mounting portion 11 is positioned on the seat central axis S.

[0066] The main body 20c has a front surface 22 facing the axial spherical side Sdd, a back surface 23 facing the axial counter-spherical side Sda, and a pair of side surfaces 24 facing each other in the axial perpendicular direction Sv. The sphere installation portion 11 is formed so as to be recessed from the front surface 22 of the main body 20c toward the axial counter-spherical side Sda. The back surface 23 is back-to-back with respect to the front surface 22. One of the pair of side surfaces 24 connects an edge of the front surface 22 on the counter-axial side Sva to an edge of the back surface 23 on the counter-axial side Sva.

[0067] The corner between one side surface 24 and the back surface 23 forms a fulcrum 25 that can come into contact with the measurement surface 53c of the measurement object 50c. Therefore, this fulcrum 25 is located on the anti-sphere side Sda of the axis with respect to the sphere installation part 11, at a location away from the seat central axis S in the axis perpendicular direction Sv. In this embodiment, the fulcrum distance D, which is the distance from the seat central axis S to the fulcrum 25 in the axis perpendicular direction Sv, is less than the radius r (see FIG. 16).

[0068] As shown in FIG. 16 , the measurement object magnet 15c is positioned such that, when the fulcrum 25 is in contact with the measurement surface 53c of the measurement object 50c, the magnetic force of the measurement object magnet 15c acting on the measurement object 50c causes a moment M to act on the main body 20c in a rotational direction around the fulcrum 25 such that the sphere 2 in contact with the sphere installation unit 11 approaches the measurement surface 53c of the measurement object 50c. Specifically, the measurement object magnet 15c is positioned closer to the sphere axis Sdd in the axial direction Sd than the fulcrum 25, and on the side where the fulcrum 25 is located in the axial direction Sv perpendicular to the axial direction. Furthermore, all of the measurement object magnets 15c are located within a region that is within a fulcrum distance D from the seat center axis S. Therefore, all of the opposing surfaces 16c of the measurement object magnets 15c are located within a region that is within a fulcrum distance D from the seat center axis S. The facing surface 16c of the measurement object magnet 15c is spaced apart from the first imaginary plane P1 and is perpendicular to the first imaginary plane P1 (see FIG. 15).

[0069] When using the measurement sphere holding jig 10c of this embodiment to measure multiple positions on the measurement surface 53c of the measurement object 50c, first, the sphere 2 of the measurement sphere 1 is brought into contact with the sphere mounting portion 11 of the measurement sphere holding jig 10c. The sphere 2 is maintained in contact with the sphere mounting portion 11 by the magnetic force of the sphere holding magnet 12. Next, the measurement sphere holding jig 10c is positioned so that one side surface 24 of the measurement sphere holding jig 10c holding the measurement sphere 1 and the opposing surface 16c of the measurement object magnet 15c face the measurement surface 53c of the measurement object 50c in the axis perpendicular direction Sv. As a result, the magnetic force of the measurement object magnet 15c brings the fulcrum 25 of the measurement sphere holding jig 10c into contact with the measurement surface 53c of the measurement object 50c, and the measurement sphere holding jig 10c is attached around the measurement position 55 (measurement surface 53c) in the measurement object 50c. Furthermore, due to the magnetic force of the measurement object magnet 15c, a moment M acts on the main body 20c in the rotational direction around the fulcrum 25 of the measurement sphere holding jig 10c, causing the sphere 2 in contact with the sphere installation part 11 to approach the measurement surface 53c of the measurement object 50c. As a result, the sphere 2 in contact with the sphere installation part 11 comes into contact with the measurement surface 53c including the measurement position 55 in the measurement object 50c.

[0070] Therefore, by using the measurement ball holding jig 10c in this embodiment, the measurement accuracy of the measurement position 55 can be improved, just as when each of the measurement ball holding jigs 10, 10a, and 10b in each of the embodiments described above is used.

[0071] The present disclosure is not limited to the embodiments described above, and various additions, modifications, substitutions, partial deletions, etc. are possible within the scope of the conceptual idea and spirit of the present invention as derived from the content defined in the claims and their equivalents.

[0072] "Addendum" The measurement ball holding jig in the above-described embodiment and modified examples can be understood, for example, as follows.

[0073] (1) The measurement ball holding jig in the first aspect is The measurement sphere holding jig 10, 10a, 10b, 10c is capable of holding a measurement sphere 1 having a sphere 2 of radius r made of a magnetic material and a reflector 3 fixed to the surface of the sphere 2, and includes a sphere mounting portion 11 capable of contacting a portion of the surface of the sphere 2, a sphere holding magnet 12 for maintaining the sphere 2 in contact with the sphere mounting portion 11, measurement object magnets 15, 15b, 15c having opposing surfaces 16, 16b, 16c capable of facing measurement objects 50, 50a, 50b, 50c made of a magnetic material, and a main body 20, 20a, 20b, 20c to which the sphere mounting portion 11, the sphere holding magnet 12, and the measurement object magnets are attached. The sphere mounting portion 11 has a seat center axis S, and is formed so that the center C of the sphere 2 in contact with the sphere mounting portion 11 is located on the seat center axis S. The ball holding magnet 12 is disposed on the seat central axis S, and is located on the axial anti-sphere side Sda, of the axial sphere side Sdd and the anti-sphere side Sda in the axial direction Sd along which the seat central axis S extends, with the sphere mounting unit 11 as the reference, on the anti-sphere side Sda, which is opposite the sphere 2 that is in contact with the sphere mounting unit 11. The main bodies 20, 20a, 20b, 20c are located on the anti-sphere side Sda with the sphere mounting unit 11 as the reference, and have fulcrums 25, 25b that can come into contact with the measurement objects 50, 50a, 50b, 50c. The fulcrums 25, 25b serve as rotation centers when the main bodies 20, 20a, 20b, 20c rotate around axes perpendicular to an imaginary plane P1 that includes the seat central axis S when in contact with the measurement objects 50, 50a, 50b, 50c. The magnets 15, 15b, 15c for the measurement object are positioned such that when the fulcrum 25, 25b is in contact with the object to be measured 50, 50a, 50b, 50c, the magnetic force of the magnets 15, 15b, 15c for the measurement object acting on the object to be measured 50, 50a, 50b, 50c causes a moment M to act on the main body 20, 20a, 20b, 20c in a rotational direction around the fulcrum 25, 25b, in which the sphere 2 in contact with the sphere installation portion 11 approaches the object to be measured 50, 50a, 50b, 50c.

[0074] When measuring a measurement position 55 in a measurement object 50, 50a, 50b, 50c using the measurement sphere holding jig 10, 10a, 10b, 10c of this embodiment, first, the sphere 2 of the measurement sphere 1 is brought into contact with the sphere mounting portion 11 of the measurement sphere holding jig 10, 10a, 10b, 10c. The sphere 2 is maintained in contact with the sphere mounting portion 11 by the magnetic force of the sphere holding magnet 12. In other words, the measurement sphere 1 is held by the measurement sphere holding jig 10, 10a, 10b, 10c. Next, the measurement sphere holding jig 10, 10a, 10b, 10c is positioned so that a portion of the main body 20, 20a, 20b, 20c of the measurement sphere holding jig 10, 10a, 10b, 10c holding the measurement sphere 1 faces the area around the measurement position 55 in the measurement object 50, 50a, 50b, 50c. As a result, due to the magnetic force of the measurement object magnets 15, 15b, 15c, the fulcrums 25, 25b of the measurement sphere holding jigs 10, 10a, 10b, 10c come into contact with positions around the measurement position 55 in the measurement objects 50, 50a, 50b, 50c, and the measurement sphere holding jigs 10, 10a, 10b, 10c are attached to the measurement objects 50, 50a, 50b, 50c around the measurement position 55. Furthermore, due to the magnetic force of the measurement object magnets 15, 15b, 15c, a moment M acts on the main bodies 20, 20a, 20b, 20c in a rotational direction around the fulcrums 25, 25b such that the spheres 2 in contact with the sphere installation portions 11 approach the measurement objects 50, 50a, 50b, 50c. Therefore, the sphere 2 in contact with the sphere installation portion 11 comes into contact with the measurement position 55 in the measurement objects 50, 50a, 50b, and 50c.

[0075] Next, the sphere 2 is rotated while maintaining contact with the sphere installation section 11 and the measurement position 55 in the measurement object 50, 50a, 50b, 50c so that the reflector 3 on the surface of the sphere 2 faces the side of the measurement device main body 5.

[0076] Next, a laser beam is irradiated from a laser oscillator in the measurement device main body 5 onto the reflecting mirror 3, and the laser beam reflected by the reflecting mirror 3 is received by a receiver in the measurement device main body 5. The measurement device main body 5 determines the coordinates of the center of the measurement sphere 1 based on the laser beam irradiated onto the reflecting mirror 3 and the laser beam received by the receiver. Furthermore, the measurement device main body 5 uses the radius r of the sphere 2 from the coordinates of the center of the measurement sphere 1 to determine the coordinates of the measurement position 55 of the measurement object 50, 50a, 50b, 50c with which the sphere 2 is in contact.

[0077] (2) The measurement ball holding jig in the second embodiment is In the measurement sphere holding jig 10, 10a, 10b, 10c of the first embodiment, the fulcrum 25, 25b is spaced apart from the seat center axis S in the axial normal direction Sv that is perpendicular to the seat center axis S within the imaginary plane P1. The measurement object magnets 15, 15b, 15c are arranged closer to the axial sphere Sdd in the axial direction Sd than the fulcrum 25, 25b, and on the side where the fulcrum 25, 25b is located in the axial normal direction Sv with respect to the seat center axis S. The measurement object magnets 15, 15b, 15c are arranged so that at least a portion of the opposing surfaces 16, 16b, 16c is present in an area whose distance from the seat center axis S is less than the distance D from the seat center axis S to the fulcrum 25, 25b.

[0078] (3) The measurement ball holding jig in the third embodiment is In the measurement ball holding jigs 10, 10b, and 10c in the second embodiment, the fulcrums 25 and 25b are disposed at positions where the distance from the seat center axis S is less than the radius r.

[0079] In this embodiment, it is possible to increase the angle LA at which the laser light can be received by the reflecting mirror 3. In other words, in this embodiment, it is possible to widen the area in which the measurement device main body 5 that emits the laser light can be arranged.

[0080] (4) The measurement ball holding jig in the fourth aspect is In the measurement ball holding jigs 10, 10b, and 10c according to the third embodiment, the fulcrums 25 and 25b are disposed at positions whose distance from the seat central axis S is longer than half the radius r.

[0081] In this embodiment, interference between the ball holding magnet 12 and the measurement object magnets 15, 15b, and 15c can be easily avoided.

[0082] (5) The measurement ball holding jig in the fifth aspect is In the measurement ball holding jig 10, 10a in any one of the second to fourth embodiments, the magnet 15 for measurement has a portion of the opposing surface 16 located within an area where the distance from the seat center axis S is less than the distance D from the seat center axis S to the fulcrum 25, and the remaining portion of the opposing surface 16 located within an area where the distance from the seat center axis S is equal to or greater than the distance D from the seat center axis S to the fulcrum 25.

[0083] (6) The measurement ball holding jig in the sixth aspect is In the measurement ball holding jig 10 in the fifth embodiment, the opposing surface 16 is parallel to the imaginary plane P1 and is located on the imaginary plane P1.

[0084] (7) The measurement ball holding jig in the seventh aspect is In the measurement ball holding jig 10a in the fifth embodiment, the opposing surface 16 is parallel to the imaginary plane P1 and spaced apart from the imaginary plane P1.

[0085] (8) In the eighth aspect, the measurement ball holding jig is In the measurement ball holding jig 10b, 10c in any one of the second to fourth embodiments, the magnets 15b, 15c for measurement objects are located within an area where all of the opposing surfaces 16b, 16c are located within a region where the distance from the seat center axis S is less than the distance D from the seat center axis S to the fulcrum 25, 25b.

[0086] (9) In the ninth aspect, the measurement ball holding jig is In the measurement ball holding jigs 10b and 10c in the eighth embodiment, the opposing surfaces 16b and 16c are perpendicular to the imaginary plane P1.

[0087] (10) In the tenth aspect, the measurement ball holding jig is In the measurement ball holding jig 10b, 10c in any one of the second to fourth embodiments, the opposing surfaces 16b, 16c are perpendicular to the first imaginary plane, which is the imaginary plane P1, and are parallel to a second imaginary plane P2 that includes the seat center axis S, and are spaced apart from the second imaginary plane P2.

[0088] (11) In the eleventh aspect, the measurement ball holding jig is In the measurement ball holding jig 10b in the tenth embodiment, the opposing surface 16b intersects with the first imaginary plane P1.

[0089] (12) In the twelfth aspect, the measurement ball holding jig is In the measurement ball holding jig 10c in the tenth embodiment, the opposing surface 16c is spaced apart from the first imaginary plane P1. [Explanation of symbols]

[0090] 1: Measurement ball 2: Sphere 3:Reflector 5: Measurement device body (laser tracker) 10, 10a, 10b, 10c: Measurement ball holding jig 11: Sphere installation part 12: Ball holding magnet 15, 15b, 15c: Magnet for measurement object 16,16b,16c: Opposite surface 20, 20a, 20b, 20c: Main body 21,21a,21b: Main body 22:Front 23: Back 24: Side 25,25b:Fulcrum 26x,26xa:first arm 26y,26ya::Second arm 27: Opposite surface 26b: Fulcrum body 27b: Back 28b: Side 29ba: First groove 29bb:Second groove 50, 50a, 50b, 50c: Measurement object 51,51a,51b: Front page 52,52a,52b:Second side 53: Tip 53a, 53b: Inner peripheral surface 53c: Measurement surface 55: Measurement position O: symmetrical axis Od: Target axial direction Od1: First axis side Od2: Second axis side Oc: Circumferential direction S: Seat center axis Sd: Axial direction Sdd: Axis sphere side Sda: Axis line anti-spherical side Sv: Axis vertical direction Svd: Central axis side Sba: Anti-center axis side P1: First virtual surface P2: Second virtual surface

Claims

1. A measurement sphere holder capable of holding a measurement sphere having a sphere of radius r formed of a magnetic material and a reflecting mirror fixed to the surface of the sphere, a sphere mounting portion capable of contacting a portion of the surface of the sphere; a ball holding magnet for maintaining the sphere in contact with the sphere placement portion; a magnet for the measurement object having a facing surface that is made of a magnetic material and can face the measurement object; a main body to which the sphere mounting portion, the sphere holding magnet, and the measurement target magnet are attached; and the sphere mounting portion has a seat central axis, and the center of the sphere in contact with the sphere mounting portion is formed to be located on the seat central axis; the ball holding magnet is disposed on the seat central axis, and is disposed on the anti-spherical axis side, which is opposite to the sphere in contact with the sphere installation portion, of the axial spherical side and the anti-spherical axis side in the axial direction in which the seat central axis extends, with the sphere installation portion as a reference; the main body is located on the opposite side of the axis from the sphere installation portion and has a fulcrum that can come into contact with the measurement object; the fulcrum serves as a rotation center when the main body rotates around an axis perpendicular to an imaginary plane including the seat central axis when in contact with the measurement object, The magnet for measurement object is arranged at a position where, when the fulcrum is in contact with the object to be measured, a moment can act on the main body in a rotation direction around the fulcrum such that the sphere in contact with the sphere installation part approaches the object to be measured due to the magnetic force of the magnet for measurement object acting on the object to be measured. Measuring ball holding jig.

2. 2. The measurement ball holding jig according to claim 1, The fulcrum is spaced apart from the seat central axis in an axis perpendicular direction to the seat central axis within the imaginary plane, the magnet for measurement is disposed closer to the axial sphere than the fulcrum in the axial direction, and on the side where the fulcrum is disposed with respect to the seat central axis in the direction perpendicular to the axial direction, and the measurement object magnet is arranged so that at least a part of the opposing surface is present within an area whose distance from the seat central axis is less than the distance from the seat central axis to the fulcrum. Measuring ball holding jig.

3. 3. The measurement ball holding jig according to claim 2, The fulcrum is disposed at a position where the distance from the seat central axis is less than the radius r. Measuring ball holding jig.

4. 4. The measurement ball holding jig according to claim 3, The fulcrum is disposed at a position at a distance from the seat central axis that is longer than half of the radius r. Measuring ball holding jig.

5. The measurement ball holding jig according to any one of claims 2 to 4, The magnet to be measured has a part of the opposing surface located in an area where the distance from the seat central axis is less than the distance from the seat central axis to the fulcrum, and a remaining part of the opposing surface located in an area where the distance from the seat central axis is equal to or greater than the distance from the seat central axis to the fulcrum. Measuring ball holding jig.

6. The measurement ball holding jig according to claim 5, The opposing surface is parallel to the imaginary plane and is located on the imaginary plane. Measuring ball holding jig.

7. The measurement ball holding jig according to claim 5, The opposing surface is parallel to the imaginary plane and spaced apart from the imaginary plane. Measuring ball holding jig.

8. The measurement ball holding jig according to any one of claims 2 to 4, The magnet to be measured has all of the opposing surfaces present in an area where the distance from the seat central axis is less than the distance from the seat central axis to the fulcrum. Measuring ball holding jig.

9. The measurement ball holding jig according to claim 8, The opposing surface is perpendicular to the imaginary surface. Measuring ball holding jig.

10. The measurement ball holding jig according to any one of claims 2 to 4, The opposing surface is perpendicular to a first imaginary surface, is parallel to a second imaginary surface including the seat central axis, and is spaced apart from the second imaginary surface. Measuring ball holding jig.

11. The measurement ball holding jig according to claim 10, The opposing surface intersects with the first imaginary surface. Measuring ball holding jig.

12. The measurement ball holding jig according to claim 10, The opposing surface is spaced apart from the first imaginary surface. Measuring ball holding jig.

Images