JP5567622B2 - stylus - Google Patents

Description

  The present invention relates to a stylus.

  As a stylus having a spherical portion having a diameter larger than the thickness of the shaft portion at the tip of the shaft portion, a device described in Patent Document 1 has been known. In this conventional example, the stylus is formed by fixing a ruby ball on the tip of the shaft and then coating a surface of the ruby ball with a DLC (diamond-like carbon) film.

JP 2006-201105 A

  However, the above-described conventional example has a drawback that the lifetime is not so long.

  That is, although the DLC film is a material having excellent wear resistance, the DLC film has a very thin thickness and is liable to be peeled off or cracked.

  The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a stylus capable of extending the life.

  In order to extend the life of the stylus, it is sufficient to form the entire spherical portion with a material having extremely excellent wear resistance, for example, diamond, and such a large size diamond can be obtained by, for example, the CVD method. Although it is not impossible if crystal diamond is grown, diamond is troublesome in the first place, and the larger the size, the greater the amount of processing work required. In addition to the above, especially when the processing shape is a curved surface, delicate processing is required as compared with a flat surface. Therefore, in order to avoid such a problem, the above-described DLC film is conventionally proposed. Has reached.

  However, as a result of diligent research, the present inventor has found that the main cause of the above-described processing problems is the property of anisotropy of wear resistance in diamond. It has been found that it does not become a big obstacle by increasing the life of the stylus expected by making it into diamond and balancing it. That is, diamond has anisotropy in wear resistance so that the wear resistance is greatly different between the crystal face (100) and the crystal face (111). After the determination, the amount of machining work must be adjusted according to the surface orientation.

The present invention has been made based on the above findings,
A stylus comprising a spherical portion 2 having a diameter larger than the thickness of the shaft portion 1 at the tip of the shaft portion 1;
The spherical portion 2 is a single-phase diamond formed by bonding a large number of diamond particles having an average particle size of the order of 10 nm toward a random orientation by direct conversion sintering under high pressure and high temperature using graphite as a starting material . The diamond polycrystalline body is made of a polycrystalline diamond, and is formed by polishing or grinding the curved or polycrystalline diamond polycrystalline body, and engaging and brazing and fixing the diamond polycrystalline body to the tip portion of the shaft portion 1. The above-mentioned object is achieved by providing a stylus.

  According to the present invention, the stylus includes a spherical portion 2 having a diameter larger than the thickness of the shaft portion 1, and the spherical portion 2 is brought into point contact or sliding contact with the surface of the measurement target. Precise point measurement or scanning measurement is made possible. The spherical portion 2 can exhibit extremely excellent wear resistance by being entirely made of diamond.

  Further, the polycrystalline diamond constituting the spherical portion 2 is formed by combining a large number of diamond particles facing irregular directions, and since there is no anisotropy of wear resistance, polishing and grinding are performed. In addition, it is not difficult to obtain a highly accurate curvature surface such as a dimension that can withstand the above-described precise measurement, in other words, sufficient sphericity. That is, in the above-mentioned diamond polycrystal, the crystal planes of the respective crystals are randomly arranged, so there is no difficulty in workability in the working direction, and the working amount corresponding to the working amount is equal throughout. Can get to.

  Furthermore, since the spherical portion 2 is formed by engaging and brazing and fixing the diamond polycrystalline body to the tip portion of the shaft portion 1, a fixing strength that can withstand the above-described measurement can be obtained by a simple fixing operation. Can do.

  Therefore, according to the present invention, since the entire spherical portion 2 is made of diamond, extremely excellent wear resistance can be stably exhibited over a long period of time, and the life of the stylus can be further extended. In the scanning measurement, in addition to the excellent low friction obtained by the spherical portion 2 being made of diamond, there is no wear resistance anisotropy as described above. Even if the contact position moves, there is no uneven wear.

  It is not impossible to obtain the polycrystalline diamond described above by sintering diamond powder using a metal binder such as cobalt and then dissolving and removing the metal binder using an acid. When produced by direct conversion sintering under ultra-high pressure and high temperature, the bond strength between particles can be further increased, thereby preventing crack growth from occurring at the grain boundaries and further reducing cleavage. . In addition, by using graphite as a starting material as described above, it is possible to achieve a higher hardness than when non-graphitic carbon is used as a starting material, so that the life of a stylus can be more effectively realized. be able to.

  On the other hand, the shaft portion 1 described above can be formed of an appropriate metal material such as stainless steel. The tip portion of the shaft portion 1 can be appropriately shaped in consideration of the fixing workability of the diamond polycrystalline body forming the spherical portion 2, but the rotating body curvature gradually decreases in diameter toward the rear end side. When the surface is formed, it can be obtained by utilizing the above-described absence of wear resistance anisotropy simply by pressing and engaging the spherical surface of the polycrystalline diamond against the rotating body curvature surface. Using the high sphericity, it is possible to easily position the center of the spherical diamond polycrystalline body on the rotation center axis of the rotator curvature surface. Further, when the engaging recess 3 is provided in one of the shaft portion 1 and the spherical portion 2 and the engaging protrusion 4 is provided in the other, and the engaging recess 3 and the engaging protrusion 4 are engaged, In addition to positioning, the fixing strength can be further improved.

The spherical diamond that can be used for the stylus above is
Agglomerated or granular diamond composed of a single phase of diamond formed by bonding many diamond particles with an average particle size of the order of 10 nm toward the irregular orientation by direct conversion sintering under high pressure and high temperature starting from graphite After the polycrystalline body is brazed and fixed in a predetermined position, the exposed outer surface is polished and curved by grinding, and then the brazing material 5 is melted and the diamond polycrystal is brazed and fixed in a different position to expose the outer surface. Can be obtained by a diamond processing method in which a curved surface is repeatedly polished and ground to form a spherical shape.
According to the present invention,
A stylus comprising a spherical portion 2 having a diameter larger than the thickness of the shaft portion 1 at the tip of the shaft portion 1;
In the spherical portion 2, a diamond polycrystal formed by bonding a large number of diamond particles in an irregular direction is processed into a curved surface, and the diamond polycrystal is engaged with the tip of the shaft portion 1, A stylus formed by brazing, or
A diamond processing method for processing diamond into a spherical shape,
After the diamond polycrystalline body formed by bonding a large number of diamond particles in an irregular direction is brazed and fixed in a predetermined posture and the exposed outer surface is processed into a curved surface, the brazing material 5 is melted to obtain a polycrystalline diamond. It is also possible to provide a diamond processing method in which the body is re-brazed and fixed in different postures, and the exposed outer surface is repeatedly curved to form a spherical shape.

  As is clear from the above description, according to the present invention, it is possible to provide a stylus that can have a longer life, and it is possible to further increase the measurement work efficiency and reduce the measurement cost. become.

It is a figure which shows the three-dimensional shape measuring apparatus using the stylus which concerns on this invention. It is the principal part enlarged view of a stylus, (a) is a principal part expanded sectional view of a front-end | tip part, (b) is the B section enlarged view of (a), and is a schematic diagram. It is a figure explaining the processing operation | work of a diamond, (a) is a figure which shows a 1st process, (b) is a figure which shows a 2nd process. FIG. 5 is a diagram illustrating a modified example of the stylus, in which (a) is an enlarged view of a main part of the first modified example, (b) is an enlarged view of an essential part of the second modified example, and (c) is an essential part of the third modified example. (D) is a principal enlarged view of a fourth modified example.

  FIG. 1 shows a three-dimensional shape measuring apparatus using a stylus according to the present invention as a stylus for measurement. The three-dimensional shape measuring apparatus includes a probe 11 to which the stylus A is attached, a feeding device 12 that moves the probe 11 in the horizontal and vertical directions, and a control unit 13 that controls driving of the feeding device 12. This three-dimensional shape measuring apparatus measures the contour shape of a measurement object 14 fixed at a predetermined position on a stone surface plate (not shown), and specifically measures, for example, a mold of an automobile engine part. .

  The probe 11 supports the stylus A so as to be movable up and down by a slide mechanism (not shown) disposed inside, and the probe sensor (not shown) vertically (height) the stylus A within a slidable range of the slide mechanism. ) Acquire coordinate information and output it to the control unit 13 described above. The acquisition of coordinate information can be performed using a laser length measuring device (not shown) installed in the probe 11 using a light interferometry using a mirror (not shown) mounted on the rear end side of the stylus A, for example.

  The feeding device 12 moves the probe 11 in the horizontal direction and the vertical direction along a predetermined path by using an actuator (not shown) controlled by the control unit 13 as power. Further, the feeding device 12 acquires the plane coordinate information and the vertical coordinate information of the probe 11 and outputs them to the control unit 13. The acquisition of these coordinate information is performed by, for example, a laser length measuring device (not shown) mounted on the feeding device 12 using a mirror installed on the stone surface plate according to the X, Y, and Z coordinates. It can be performed in the same way.

  The controller 13 controls the actuator described above so that the probe 11 moves according to a predetermined movement path on preset three-dimensional coordinates. The setting of the movement path can be performed according to the shape of the measurement object 14 if design information of the measurement object 14 is taken in beforehand. In addition, when coordinate information is input from the probe 11 or the feeding device 12 described above, the control unit 13 outputs the coordinate information to the output unit 15. A display device or the like (not shown) is connected to the output unit 15 so that the operator can be notified of the measurement result. The measurement results can be efficiently displayed by, for example, those obtained from the feeding device 12 with respect to the plane coordinates, and those obtained from the feeding device 12 and those from the probe 11 with respect to the vertical coordinates. Is possible.

  The stylus A is disposed at a connecting portion 16 formed to be connectable to the probe 11, a shaft portion 1 extending from the connecting portion 16 in a direction opposite to the probe 11, and a tip of the shaft portion 1. And a spherical portion 2. In this embodiment, the connecting portion 16 has a male screw 16a screwed to a female screw (not shown) formed on the probe 11, and a base end side of the male screw 16a orthogonal to the longitudinal direction of the male screw 16a. The positioning surface 16b comes into contact with the outer wall surface of the probe 11 around the female screw described above, so that the threading stroke of the male screw 16a into the female screw can be positioned.

  The shaft portion 1 is formed in a columnar shape, has an appropriate length so as not to obstruct contact with the measurement object 14 of the spherical portion 2, and has a diameter in a cross section that is appropriately larger than the diameter of the spherical portion 2. Small size. The thickness of the shaft portion 1 can be determined in consideration of the rigidity that does not easily bend when the spherical portion 2 contacts the measurement object 14 at a predetermined pressure or slides at a predetermined speed. it can. In this embodiment, the shaft portion 1 is formed in an equal cross-sectional shape in the longitudinal direction, but considering that it does not interfere with the contact of the spherical portion 2 as described above, for example, a frustoconical shape, A stepped shape including a diameter part and a small diameter part can be configured such that the thickness of the tip side closer to the measurement object 14 is made thinner. The shaft portion 1 and the connecting portion 16 described above are integrally formed of an appropriate metal material such as stainless steel.

  The spherical portion 2 is made of a polycrystalline diamond and has a spherical shape with a predetermined sphericity. The spherical portion 2 can be formed by polishing and grinding a lump or granular diamond such as a trade name “Sumidia Binderless” manufactured by Sumitomo Electric Industries, Ltd.

  Specifically, the diamond polycrystalline body can be produced by sintering a high-purity isotropic graphite molded body at a temperature of 2300 ° C. or higher at a pressure of 15 GPa at the same time as conversion to diamond. As its mechanical properties, it has hardness exceeding that of a diamond single crystal, and since the intergranular bonding force is strong, crack propagation is prevented at the grain boundary, so that there is no cleaving property. As shown in Fig. 3, it is a combination of a large number of diamond particles oriented in a random orientation, so there is no anisotropy in wear resistance, and it is heat resistant because it consists of a single phase of diamond that does not contain any binding aids or binders. It is also excellent in properties. In FIG. 2, the two-dot chain line schematically shows the outer peripheral edge of the spherical portion 2, and the above-mentioned diamond particles have an average particle size of the order of 10 nm.

  The above stylus A is formed by fabricating the support member 19 constituting the connecting portion 16 and the shaft portion 1 and the spherical hard body 20 constituting the spherical portion 2 and then assembling them. In this embodiment, the support member 19 is a cut-out product of stainless steel, and is formed by cutting out from, for example, a round bar. Further, as shown in FIG. 2, a conical concave portion 21 is formed at the front end portion of the support member 19. The concave portion 21 has a conical shape that gradually decreases in diameter toward the rear end side by cutting or the like. When the hard body 20 is pressed against the recess 21, the spherical hard body 20 engages with the conical surface, and the conical surface functions as the positioning portion 22, so that the center point of the hard body 20 is the central axis of the conical recess 21. It is positioned on the line, that is, on the central axis of the shaft portion 1.

  On the other hand, in this embodiment, the hard body 20 is formed by grinding and grinding a diamond polycrystalline body having an appropriate shape such as a cylinder into a spherical shape with a diamond grindstone or the like. In this process, first, as shown in FIG. 3A, a cylindrical polycrystalline diamond is brazed and fixed to a free end of an appropriate rod-shaped member 23 with a silver brazing (brazing material 5), and then the rod-shaped member. The base end side of 23 is supported at a predetermined position by a collet chuck or the like (not shown), and a diamond grindstone or the like (not shown) is moved on a predetermined hemisphere around a polycrystalline diamond fixed at a predetermined position. The As a result, the diamond polycrystalline body is curved into a hemispherical shape as shown by a two-dot chain line in FIG. When this processing is completed, the silver braze 5 is melted to separate the polycrystalline diamond from the rod-shaped member 23. As described above, since the polycrystalline diamond has no wear resistance anisotropy, a curved surface with excellent accuracy can be obtained by the above-described curved surface processing. Note that the curvature surface obtained as described above has an aspect like an envelope, like an aggregate of a large number of crystal faces of fine diamond particles, as shown in an enlarged view in FIG.

  Next, as shown in FIG. 3B, this time, the polycrystalline diamond is rotated 120 degrees around the center point in the direction along the paper surface, and the rod-like member 23 is formed on the curvature surface formed by processing as described above. After brazing and fixing again, a diamond grindstone or the like is moved on the hemispherical surface in the same manner as described above, and the unprocessed region of the polycrystalline diamond is curved. When this processing is completed, the silver braze 5 is melted again to separate the polycrystalline diamond from the rod-shaped member 23. Finally, the polycrystalline diamond is rotated about 120 degrees in the same manner, and the rod-shaped member 23 is curved in the curvature plane. After brazing and fixing again, the unprocessed area is processed into a curved surface.

  By the above, spherical processing of the diamond polycrystalline body is completed, and thereafter, if the silver braze 5 is melted, a spherical diamond polycrystalline body separated from the rod-shaped member 23 is obtained. As shown in FIG. 3, the above-mentioned support is provided at the tip of the rod-like member 23 so that the diamond polycrystal body can be positioned at a predetermined position by engaging with the diamond polycrystal body whose curvature surface has already been processed. Similar to the member 19, a conical recess 24 is formed toward the rear end side.

  The above-described stylus A is formed by brazing and fixing the spherical hard body 20 formed as described above to the tip of the support member 19 with a silver solder 5. In the above description, the case where the appropriate rod-shaped member 23 is used to support the polycrystalline diamond in a predetermined position during processing has been described. However, the above-described support member 19 can be used as it is instead. In addition, the rotation angle of the diamond polycrystalline body after melting the silver solder 5 can be determined in consideration of work efficiency, and it will be necessary to process the diamond polycrystalline body into a spherical shape according to this rotation angle. In addition, the number of times the silver solder 5 is melted is determined.

  For example, as shown in FIG. 1, the above three-dimensional shape measuring apparatus moves the probe 11 with the feeding device 12 so that the spherical portion 2 is in sliding contact with the surface of a mold or the like that is the measurement object 14. By sequentially recording the three-dimensional coordinates of the stylus A, it is possible to measure a precise contour shape such as a mold including dimensions and angles. As described above, since the polycrystalline diamond has no wear resistance anisotropy, the spherical portion 2 is less likely to be unevenly worn due to sliding contact, and friction due to a change in the contact position with the measurement object 14. It can also be expected to suppress resistance fluctuations.

  In the measurement, for example, the dimensional error of the spherical portion 2 is specified in advance by obtaining the difference between the measurement size of the reference sphere obtained by tracing the surface of the reference sphere with the spherical portion 2 and its sphericity. In addition, it is possible to obtain a more precise measurement result by giving such a dimensional error as correction information of coordinate information at the time of measurement.

  In addition, although the case where the supporting member 19 is formed of stainless steel has been described above, it is sufficient to select an appropriate material such as a cemented carbide material in accordance with the contact pressure of the spherical portion 2 to the measuring object 14 or the like. Moreover, although the case where the male and female screws are formed on the connecting portion 16 and the probe 11 to connect them is shown, an appropriate connecting means such as adhesion may be used in addition to such screwing. In addition, the stylus A can be configured by increasing the number of the shaft portions 1 and the spherical portions 2 according to applications, such as a cross stylus.

  FIG. 4A shows a first modification of the present invention. In this modified example and other modified examples described later, the same elements as those in the above-described embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted. In this modification, a hemispherical recess 21 is formed at the tip of the support member 19 by cutting or the like as shown in FIG. The recess 21 has the same radius of curvature as the curvature surface of the hard body 20.

  In addition, an engagement protrusion 4 extending conically toward the distal end is formed at the distal end of the support member 19, that is, the bottom of the recess 21, and the hard body 20 can be engaged with the engagement protrusion 4. A dimple-like engagement recess 3 is formed. The center axis of the engaging projection 4 is located on the center axis of the shaft portion 1, and the center of the spherical portion 2 is located on the center axis of the dimple forming the engaging recess 3. Is engaged with the engaging recess 3, the center of the hard body 2 is positioned on the central axis of the shaft 1. In addition, the fixing strength of the hard body 20 to the support member 19 is improved by this engagement.

  FIG. 4B shows a second modified example. In this modified example, a columnar engagement protrusion 4 whose central axis is located on the central axis of the shaft portion 1 is formed at the tip of the support member 19. The base end side of the engaging protrusion 4 is a flat surface 25 orthogonal to the engaging protrusion 4. On the other hand, the engaging recess 3 is formed in the hard body 20 by a drilling process toward the center thereof.

  Further, in this modification, the hard body 20 has a curved surface only on the outer surface on the tip side, that is, on the side opposite to the shaft portion 1, and includes a mounting portion 26 having a cylindrical shape on the shaft portion 1 side. Specifically, as shown in FIG. 4B, the curvature surface is formed in an opening angle range slightly exceeding 180 degrees in the hard body 20 in consideration of smooth contact with the measurement object 14. The mounting portion 26 formed in a cylindrical shape provides a flat support surface 26a on the outer surface of the hard body 20, and the engagement recess 3 described above is opened in a direction orthogonal to the support surface 26a. When the engagement protrusion 4 is engaged with the engagement recess 3, the support surface 26 a is aligned with the flat surface 25 at the base end of the engagement protrusion 4, whereby the hard body 20 can be stably and firmly fixed to the support member 19. It becomes possible. In this modification, it is possible to reduce the amount of curved surface processing work of the hard body 20.

  FIG. 4C shows a third modification. In this modification, the engagement protrusion 4 having a frustoconical shape is formed on the shaft portion 1 side of the hard body 20. A neck portion 27 that gradually decreases in diameter toward the tip is formed at the tip of the support member 19, and the tip of the neck 27 has a frustoconical shape that engages with the tip of the engagement protrusion 4. An engagement recess 3 is formed. When the engagement protrusion 4 is engaged with the engagement recess 3, a constricted portion 28 is formed on the shaft portion 1 side of the hard body 20, whereby the shaft portion 1 is brought into contact with the measurement object 14. Becomes more difficult to interfere with the measurement object 14.

  FIG. 4D shows a fourth modification. In this modification, the support member 19 is provided with a through-hole 29 penetrating in the longitudinal direction. The probe 11 (not shown) is provided with appropriate light emitting means 30 such as an LED that emits a light emission color such as red, which is easy to identify visually, and the light emitted from the light emitting means 30 is inserted into the through hole 29 described above. The light is irradiated from the shaft 1 side toward the hard body 20 through the optical fiber 31. As a result, the hard body 20 has a color that can be easily visually identified to easily recognize the outer peripheral surface thereof, and easily recognizes the presence or absence of contact with the measurement object 14. In the above, the case where the support member 19 is provided with the through hole 29 and the optical fiber 31, that is, the light guiding means is inserted has been described. If the light intensity incident on the hard body 20 can be appropriately ensured by using a highly linear light such as light, it is not necessary to provide the light guide means.

DESCRIPTION OF SYMBOLS 1 Shaft part 2 Spherical part 3 Engagement recessed part 4 Engagement protrusion 5 Brazing material

Claims (2)

A stylus having a spherical portion having a diameter larger than the thickness of the shaft portion at the tip of the shaft portion,
The spherical portion of the graphite starting material and the ultra-high pressure high temperature direct conversion sintering the average particle diameter of 10nm order diamond single phase multiple generated attached toward the irregular orientation of the diamond particles in diamond A stylus formed of a polycrystalline body , wherein the massive or granular diamond polycrystalline body is processed into a curved surface by polishing and grinding, and the diamond polycrystalline body is engaged with a tip portion of a shaft portion and fixed by brazing. . A diamond processing method for processing diamond into a spherical shape,
Agglomerated or granular diamond composed of a single phase of diamond formed by bonding many diamond particles with an average particle size of the order of 10 nm toward the irregular orientation by direct conversion sintering under high pressure and high temperature starting from graphite After the polycrystalline body is brazed and fixed in a predetermined posture, the exposed outer surface is polished and ground by grinding, and then the brazing material is melted and the diamond polycrystalline body is brazed and fixed again in a different posture. A diamond processing method in which a curved surface is repeatedly processed by polishing and grinding to form a spherical shape.

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