JP4838188B2 - Drill for hole formation - Google Patents

Description

  The present invention relates to a hole-forming drill for punching a hard and brittle material plate such as glass.

  Conventionally, as a tool to make a hole in a hard and brittle material plate, a hole formation that makes a hole by contacting the hard and brittle material plate while rotating a grindstone part with a grindstone made of diamond etc. attached to the tip of a steel shank When drilling using such a hole forming drill, the grindstone is rotated around the shaft center of the shank and brought into contact with the hard and brittle material plate. A perforation is formed.

Japanese Patent Laid-Open No. 6-1444859 (page 3, FIG. 4)

  However, in Patent Document 1, since the inner peripheral surface of the hole formed in the hard and brittle material plate by the hole forming drill is formed linearly in the axial direction of the hole forming drill, the hole is formed. During handling such as movement of the hard and brittle material plate, stress due to bending load was concentrated on the inner peripheral surface of the hole, and the hard and brittle material plate was likely to be damaged, and handling of the hard and brittle material plate was difficult .

  For example, when a hard and brittle material plate having a through hole is gripped by gripping means having a moving function and the plate surface is arranged substantially parallel to the floor surface, the entire hard and brittle material plate is bent by its own weight. A load will be generated. The stress due to the bending load is likely to act in a through-hole penetrating the front and rear surfaces of the plate surface at a predetermined position of the hard and brittle material plate spreading in the plane direction. For example, in a state where the hard and brittle material plate is gripped by the gripping means. When attempting to move, even a slight impact may cause a crack in the inner peripheral surface of the through hole, resulting in damage to the hard and brittle material plate.

  The present invention has been made paying attention to such a problem, and even if the hard brittle material plate in which the grinding hole is formed is gripped and moved, the hard brittle material plate is difficult to break. It is an object of the present invention to provide a hole forming drill capable of forming a grinding hole.

In order to solve the above-described problem, a drill for forming a hole according to claim 1 of the present invention is provided.
A grindstone portion is provided along the axial direction on the peripheral surface of the shank acting as a rotating shaft, the grindstone portion is disposed in a through-hole of a hard and brittle material plate to be ground , and the grindstone portion is disposed on the shaft center of the shank. by providing an eccentric motion between to pivot Rutotomoni the through hole as the center, a hole forming drill grinding an inner surface of the through hole,
The grindstone portion has a curved grinding portion formed of a curved surface having a tangential slope continuous along the axial direction of the rotating shaft, and the curved grinding portion bulges so that the tangential slope continuously increases. The bulging curved surface is disposed in the through hole when the inner surface of the through hole is ground, and the curved grinding portion is a hard and brittle material to be ground. It is characterized by having a length equal to or greater than the thickness of the plate .
According to this feature, the curved grinding portion formed in the grindstone portion of the hole forming drill can form a curved surface having a continuous tangential slope on the hard brittle material plate to be ground. Even if a bending load is applied to the plate, the stress due to the bending load is continuously dispersed in the tangential direction of the curved surface on the inner surface of the grinding hole, so that a grinding hole having a shape in which the hard and brittle material plate is difficult to break can be formed.
Further, by giving an eccentric motion between the curved grinding surface which is a curved surface bulging in the radial direction of the rotating shaft and the grinding hole of the hard and brittle material plate, the inner surface of the grinding hole can be formed into a larger-diameter curved surface. .

The hole forming drill according to claim 2 of the present invention is the hole forming drill according to claim 1 ,
The curved surface grinding portion has a chamfered recess formed of a curved surface that is continuous with the bulging curved surface and is reduced in diameter in the radial direction of the rotating shaft.
According to this feature, in addition to the curved surface bulging in the radial direction of the rotating shaft, the curved surface grinding portion having a chamfered recess having a diameter reduced in the radial direction of the rotating shaft, and grinding of the brittle material plate A chamfered portion using a chamfered concave portion can be formed on the inner surface of the grinding hole by giving an eccentric motion between the hole and the hole.

The hole forming drill according to claim 3 of the present invention is the hole forming drill according to claim 1 or 2 ,
The grindstone portion includes a penetrating grindstone portion that is provided on the front end side and penetrates the hard and brittle material plate, and the curved grinding portion that is disposed on the rear side of the penetrating grindstone portion. .
According to this feature, after the through hole is formed in the hard and brittle material plate by the penetrating grindstone portion on the tip side of the grindstone portion, an eccentric motion is applied between the curved grinding portion and the grinding hole of the hard and brittle material plate to perform grinding. Thus, it is possible to form a through hole having a curved surface on the inner peripheral surface consistently with a single hole forming drill.

The hole forming drill according to claim 4 of the present invention is the hole forming drill according to claim 3 ,
The outer diameter of the curved grinding portion is formed to be substantially the same as or smaller than the outer diameter of the penetrating grindstone portion.
According to this feature, since the outer diameter of the curved grinding portion is formed to be substantially the same as or smaller than the outer diameter of the penetrating grindstone portion, the penetration of the hard and brittle material plate by the penetrating grindstone portion on the tip side of the grindstone portion. At this time, the through-hole can be formed by setting the eccentric motion between the through-whetstone portion and the hard and brittle material plate to 0 or slightly.

  Examples of the present invention will be described below.

  A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic perspective view showing an application example of a hard and brittle material plate according to the present invention. FIG. 2 is a perspective view showing the hole forming drill in Example 1 of the present invention. FIG. 3 is a front view similar to FIG. FIG. 4 is a side view similar to FIG. FIG. 5 is a cross-sectional side view similar to FIG. FIG. 6 is a cross-sectional view showing a situation where a plate glass is perforated as in FIG. FIG. 7 is a cross-sectional view taken along the line AA of FIG. FIG. 8A is a cross-sectional view showing a situation where the plate glass is penetrated similarly to FIG. 2, and FIG. 8B is a cross-sectional view showing a situation where grinding is performed by the intermediate grindstone portion. FIG. 9A is a cross-sectional view showing a ground hole of a plate glass after grinding, as in FIG. 2, and FIG. 9B is a cross-sectional view showing a state in which a bending load is applied to the plate glass. 18A is a diagram illustrating the inclination angle of the tangent at the position of the grinding hole in the penetration direction in Example 1, and FIG. 18B is a graph showing the inclination angle of the tangent at the position of the grinding hole in the penetration direction. It is.

  First, as shown in FIG. 1, an application example of a hard and brittle material plate provided with through holes penetrating the front and back surfaces will be described. The plasma display panel 1 includes a front case portion 2 and a back case portion 8 which are combined with each other to form a case, and an internal unit 10 accommodated in the case.

  The internal unit 10 includes a chassis member 7 as a heat dissipation holding plate, a display panel 9 supported on the front surface of the chassis member 7, and heat as an adhesive member interposed between the chassis member 7 and the display panel 9. The conductive sheet 6 and the optical function filter 3 having functions such as antistatic, color tone / brightness correction, electromagnetic wave shielding, etc., are disposed on the front surface of the display panel 9.

  The display panel 9 is composed of a plate glass 4 provided on the front side and a plate glass 5 as a hard and brittle material plate provided on the back side. The plate glass 4 has a long side direction longer than the plate glass 5 and a short side. The direction is short. Accordingly, there is a region where the plate glass 4 and the plate glass 5 do not overlap each other, and terminals (not shown) connected to electrodes (not shown) provided in the display panel 9 are formed in the non-polymerized region. . A plurality of film-like wiring (not shown) having a connector (not shown) at the tip is crimped to this terminal, and the connector is provided on a circuit board (not shown) arranged on the back surface of the chassis member 7. By being coupled to (not shown), the circuit board and the display panel 9 are electrically connected.

  The peripheral portions of the front side glass plate 4 and the rear side glass plate 5 are bonded and sealed with a sealing material (not shown) made of low melting point glass to form a gas discharge space, and the gas discharge is sealed. A rare gas (such as a mixed gas of neon and xenon) having a predetermined pressure is sealed in the space.

  And the through-hole for distribute | circulating the noble gas enclosed in the inside of the above-mentioned gas discharge space is formed in the predetermined location near the corner | angular part of the plate glass 5 so that the front and back of the plate glass 5 may be penetrated. Below, the formation process of the through-hole by the drill for hole formation is demonstrated.

  Reference numeral 11 in FIG. 2 is a diamond drill as a hole forming drill in the present embodiment. The diamond drill 11 includes a diamond grindstone portion 12 as a grindstone portion in which diamond is mounted on a front end surface and an outer peripheral surface, and a rotating shaft. It is comprised with the steel shank 13 which acts as. The diamond grindstone portion 12 is manufactured as a metal bond grindstone or an electrodeposition grindstone using diamond abrasive grains.

  Further, as shown in FIGS. 2 to 4, the diamond grindstone portion 12 includes a tip grindstone portion 14 as a small-diameter penetrating grindstone portion formed on the tip side and an intermediate portion formed from the tip grindstone portion 14. And a rear grinding wheel portion 15 as a curved grinding portion having a large diameter.

  Coarse diamond abrasive grains having a large particle size are attached to the tip grindstone portion 14, and fine diamond abrasive grains having a particle size smaller than that of the diamond abrasive grains adhered to the tip grindstone portion 14 are attached to the rear grindstone portion 15. It is attached.

  Further, the tip grindstone portion 14 has a substantially cylindrical shape formed with substantially the same diameter along the axial direction, and a cylindrical surface 14 a is formed on the side periphery of the tip grindstone portion 14. On the distal end side, a conical surface 14b is formed so that the diameter decreases toward the distal end. As shown in the partial enlarged perspective view of FIG. 2, the tip of the tip grindstone 14 has a tip surface 14c formed by flattening the tip of the cone formed by the cone surface 14b. In other words, the shape of the tip portion of the tip grindstone portion 14 is a truncated cone shape.

  The rear grindstone 15 is provided on the rear side in the axial direction of the diamond drill 11 with respect to the tip grindstone 14, and has a curved surface that bulges in the radial direction of the rotating shaft. More specifically, the rear grindstone 15 is a curved surface in which the tangential inclination continues along the axial direction of the rotation axis, and an opening grinding surface 15a for grinding the opening on the surface of the hard and brittle material plate; Similarly, an opening grinding surface 15c that grinds the opening on the back surface of the hard and brittle material plate, and the diameter of the opening grinding surface 15a and 15c is gradually increased from that of the hard and brittle material plate. It has a curved surface comprising an inner grinding surface 15b to be ground. Further, the rear grindstone portion 15 includes a continuous curved surface that is substantially symmetrical in the axial direction with a central portion located in the middle of the inner grinding surface 15b in the axial direction of the rotating shaft.

  At the center portion of the tip surface 14c of the tip grindstone portion 14 is formed a minute recess 14d that is formed in a substantially hemispherical shape. Further, as shown in FIG. 3, the tip surface 14c of the tip grindstone portion 14 has a substantially circular shape when viewed from the front of the diamond drill 11, and the recess 14d formed on the tip surface 14c is a concentric circle of the tip surface 14c. Is formed.

  Next, the process of grinding the plate glass 5 as a hard and brittle material plate using the diamond drill 11 will be described in detail with reference to FIGS. As shown in FIG. 5, when grinding the plate glass 5, which is a hard and brittle material plate, using the diamond drill 11, first the diamond drill 11 is rotated about the axis α of the shank 13, and the tip grindstone portion 14 is brought into contact with the surface of the plate glass 5. At this time, since the tip of the tip grindstone portion 14 has a truncated cone shape, the pressing force is concentrated on the tip surface 14c, and the plate glass 5 is easily ground.

  Further, as shown in FIG. 6, the diamond wheel 12 of the diamond drill 11 rotates about the axis α of the shank 13, and a relative eccentric motion occurs between the diamond wheel 12 and the plate glass 5. It has come to be given.

  The eccentric motion of the diamond drill 11 will be described in detail. As shown in FIG. 7, the cylindrical surface 14 a of the tip grindstone portion 14 of the diamond drill 11 has a substantially circular grinding hole 17 that is a surface to be ground formed on the plate glass 5. The cylindrical surface 14a of the tip grindstone 14 abuts over the entire circumference of the inner peripheral surface of the grinding hole 17 while rotating the diamond drill 11 about the axis α in the direction a. As described above, the axis α of the shaft rotation of the diamond drill 11 is rotated in the b direction around the eccentric shaft β, that is, the diamond drill 11 is rotated on the planetary axis about the eccentric shaft β. The eccentric shaft β is the central axis of the circular grinding hole 17.

  As a means for giving a relative eccentric motion between the diamond drill 11 and the plate glass 5, a first motor (not shown) that fixes the plate glass 5 in a stationary state and rotates the diamond drill 11 about the axis α. ) And a second motor (not shown) for rotating the diamond drill 11 and the first motor around an eccentric shaft β that is the central axis of the grinding hole 17. There is a method of giving a relative eccentric motion between the diamond drill 11 and the plate glass 5 by driving both.

  Further, by giving an eccentric motion to the diamond drill 11, the diameter of the grinding hole 17 formed in the plate glass 5 is larger than the outer diameter of the tip grindstone portion 14, and as will be described later, the outer diameter of the rear grindstone portion 15. It is formed to be larger. The diameter of the grinding hole 17 changes depending on the separation distance e between the axis α of the rotation axis of the diamond drill 11 and the eccentric shaft β of the eccentric motion, and the separation between the axis α and the eccentric shaft β. If the distance e is large, the diameter of the grinding hole 17 is formed large.

  Furthermore, in the diamond drill 11 in the present embodiment, the diamond grindstone 12 is rotated about the axis α of the shank 13, and the tip surface 14c passes through at least the center point (eccentric axis β) of the grinding hole 17. Further, the plate glass 5 is ground by giving an eccentric motion between the diamond grindstone portion 12 and the plate glass 5. Therefore, when the diamond grindstone 12 is axially rotated, the tip of the diamond grindstone 12 that is eccentrically moved at the position corresponding to the recess 14d and the remaining portion of the plate glass 5 generated at the center point of the grinding hole 17 (eccentric axis β). The surface 14c can be ground away.

  Moreover, the recessed part 14d can accommodate temporarily the chip generate | occur | produced when the plate glass 5 is ground. Therefore, it is possible to prevent a reduction in the grinding efficiency of the diamond drill 11 caused by the chips being interposed between the tip surface 14 c of the diamond grindstone 12 and the plate glass 5. In the grinding using the diamond drill 11, cleaning water can be poured into the gap between the grinding hole 17 and the tip grindstone portion 14, so that chips and the like generated by grinding can be ground while washing with this cleaning water. It has become.

  Further, the concave portion 14d has a shape that becomes narrower as it goes to the inner portion thereof. By doing so, chips and the like generated during grinding of the glass sheet 5 can be easily removed from the concave portion 14d. Since powder or the like is less likely to be clogged in the recess 14d, the diamond drill 11 can be easily maintained after use. Further, the vicinity of the axis α of the rotation axis of the diamond drill 11 is a portion where the rotation diameter is substantially 0 and there is almost no rotational movement. A place where there is almost no movement can be used as a space for storing chips. Furthermore, by forming a part of the tip surface 14c where the defect or the like is most likely to occur due to the grinding of the hard and brittle material as the concave part 14d, the generation of the defect can be prevented.

  After the tip grindstone portion 14 penetrates the plate glass 5, the cylindrical surface 14a of the tip grindstone portion 14 is gradually increased by increasing the separation distance e between the shaft rotation axis α of the diamond drill 11 and the eccentric shaft β of the eccentric motion. By grinding the inner peripheral surface of the grinding hole 17, the grinding hole 17 is enlarged so that the diameter of the grinding hole 17 is increased.

  8A, the diameter L2 of the grinding hole 17 is formed to be larger than the outer diameter L1 of the inner grinding surface 15b of the rear grinding wheel portion 15 by the above-described eccentric motion by the tip grinding wheel portion 14. After that, the diamond grindstone 12 is further inserted into the grinding hole 17 in the axial direction, and the rear grindstone 15 is brought into contact with the inner peripheral surface of the grinding hole 17. Then, as shown in FIG. 8B, while rotating the diamond drill 11 around the axis α, the peripheral surface of the rear grindstone 15 extends over the entire inner peripheral surface of the grinding hole 17. The diamond drill 11 is moved eccentrically.

  Further, after forming the grinding hole 17 penetrating the plate glass 5 by the tip grindstone portion 14 in this way, the relative position between the diamond grindstone portion 12 and the plate glass 5 is moved in the axial direction of the diamond drill 11, and the tip grindstone portion 14 is moved. By applying an eccentric motion between the rear grinding wheel portion 15, which is a curved surface bulging in the radial direction of the rotating shaft formed on the rear side, and the plate glass 5, grinding is performed consistently with one diamond drill 11. Thus, a grinding hole 17 having a curved surface with a shape along the rear grinding wheel portion 15 can be formed in the plate glass 5. That is, as shown in FIG. 9A, the grinding hole 17 as a through hole is a curved surface that expands radially outward along the curved surface bulging radially outward of the rear grindstone 15. It is formed. Specifically, in the vicinity of the front surface 5a and the back surface 5b of the plate glass 5, the diameter L2 is formed, and the diameter gradually increases toward the intermediate surface 5c, and the intermediate surface 5c has a diameter L3 larger than the diameter L2. It is formed. In addition, since the back grindstone part 15 is formed in a larger diameter than the front-end grindstone part 14, the diamond drill 11 of a present Example is suitable for the use which forms the comparatively large diameter grinding hole 17. FIG. That is, the inner surface of the grinding hole 17 is formed into a larger-diameter curved surface by giving an eccentric motion between the rear grinding wheel portion 15 which is a curved surface bulging in the radial direction of the rotating shaft and the grinding hole 17 of the plate glass 5. it can.

  In addition, since diamond abrasive grains finer than diamond abrasive grains attached to the tip grindstone portion 14 are adhered to the rear grindstone portion 15, the rear grindstone portion 15 can chamfer the inner peripheral surface of the grinding hole 17. It has become. It is also possible to provide a conical surface in the diamond grindstone 12 and chamfer the periphery of the grinding hole 17 using the conical surface.

  In this way, after forming the grinding hole 17 by penetrating the plate glass 5 using the tip grinding wheel portion 14 to which coarse diamond abrasive grains are first attached, the grinding hole is formed by the rear grinding stone portion 15 to which fine diamond abrasive grains are adhered. By chamfering 17, not only the grinding time for forming the grinding hole 17 in the plate glass 5 can be shortened, but also the replacement work between the drill for penetration and other chamfering tools is not required, and the grinding hole 17 is formed. The work time can be shortened.

  Next, as shown in FIG. 18A, the inclination of the tangent in the grinding hole 17 formed in the glass sheet 5 of the present embodiment will be described. The tangent to the virtual reference plane K parallel to the surface 5 a of the glass sheet 5. The inclination angle θ of FIG. 18 continuously changes as θ1 to θ6 illustrated in FIG. As shown in FIG. 18B, the inclination angle θ (vertical axis) of the tangent line at the position t (horizontal axis) in the penetration direction of the grinding hole 17 formed in the plate glass 5 is the surface 5a (t = 0) continuously increases toward the back surface 5b (t = T). Specifically, in the virtual intermediate surface 5c (t = T / 2) between the front surface 5a and the back surface 5b of the plate glass 5, the inclination angle θ4 indicates π / 2, and the surface of the plate glass 5 is centered on the intermediate surface 5c. The inclination angle θ changes substantially symmetrically toward the back surface.

  Next, as shown in FIG. 9B, the bending load acting on the plate glass 5 having the grinding holes 17 formed by the diamond drill 11 as described above will be described. For example, the surface 5a of the plate glass 5 is used as the upper surface. When gripped by a gripping means (not shown), a bending load is applied in the direction of the outlined arrow. Specifically, a tensile force is generated on the surface 5a side around the intermediate surface 5c of the plate glass 5, and this tensile force acts as the largest force on the surface 5a. Similarly, a compressive force is generated on the back surface 5b side of the intermediate surface 5c, and this compressive force acts as the largest force on the back surface 5b.

  Next, the bending load acting on the inner peripheral surface of the grinding hole 17 penetrating the front and back surfaces of the plate glass 5 will be described. The stress due to the bending load acts toward the tangential direction in the penetrating direction of the inner peripheral surface of the grinding hole 17. To do. As described above, the rear grinding wheel portion 15 formed in the diamond grinding wheel portion 12 of the diamond drill 11 can form the grinding hole 17 having a curved surface with a continuous tangential slope in the glass plate 5. Even when a bending load is applied, the stress due to the bending load is continuously dispersed in the tangential direction of the curved surface on the inner surface of the grinding hole 17, so that the grinding hole 17 having a shape in which the plate glass 5 is difficult to break can be formed.

  In particular, as in this embodiment, the rear grindstone portion 15 of the diamond drill 11 is located on the inner side of the opening portion of the plate glass 5 from the opening grinding surfaces 15a and 15c for grinding the openings on the front surface 5a and the back surface 5b of the plate glass 5. As shown in FIG. 9 (a), openings that are ground by the opening grinding surfaces 15a and 15c have a curved surface that gradually increases in diameter toward the inner grinding surface 15b that grinds the side. Since the hole diameter L2 of the portion can be formed smaller than the hole diameter L3 ground by the inner grinding surface 15b, the bending load is applied to the front surface 5a and the rear surface 5b of the plate glass 5 where the bending load applied to the plate glass 5 acts most greatly. In contrast, it is possible to improve the difficulty of cracking. Further, since the direction in which the stress due to the bending load applied to the plate glass 5 is dispersed can be formed in a direction away from the grinding hole 17 in the radial direction, the bending load concentrated on the grinding hole 17 is applied to the peripheral portion of the grinding hole 17 in the plate glass 5. The glass sheet 5 is difficult to break.

  Further, since the rear grinding wheel portion 15 having a continuous curved surface that is substantially symmetrical in the axial direction around the center portion of the inner grinding surface 15b, a curved surface along the rear grinding wheel portion 15 can be formed on the plate glass 5, A bending load in the direction in which a tensile force is applied to the front surface 5a of the plate glass 5 and a compressive force is applied to the back surface 5b, which occurs when the front surface 5a of the plate glass 5 is gripped upward, and the reverse surface 5b of the plate glass 5 is opposite to this direction. The same difficulty of cracking can be generated against a bending load in which a tensile force is applied to the back surface 5b of the plate glass 5 and a tensile force is applied to the surface 5a.

  Further, the rear grindstone portion 15 is formed in a curved surface having only a uniform curvature along the penetrating direction, and the inclination of the tangent line is inclined on the inner peripheral surface of the grinding hole 17 of the plate glass 5 formed by the rear grindstone portion 15. Since it is uniformly continuous, the stress due to the bending load can be evenly dispersed.

  Next, a hole forming drill according to Example 2 will be described with reference to FIGS. FIG. 10 is a side view showing the hole forming drill in Embodiment 2 of the present invention. FIG. 11A is a cross-sectional view showing a situation where the intermediate grindstone is ground as in FIG. 10, and FIG. 11B is a cross-sectional view showing a grinding hole of the plate glass after grinding. In addition, the same structure as the said Example is abbreviate | omitted.

  FIG. 10 is a diamond drill 21 as a hole forming drill in the second embodiment, and a rear grindstone portion 25 as a curved grinding portion is an inner grinding surface 25b that is a curved surface bulging in the radial direction of the rotating shaft. In addition, curved surfaces having opening grinding surfaces 25a and 25c as chamfered concave portions having a diameter reduced in the radial direction of the rotating shaft are provided on both the upper and lower sides of the inner grinding surface 25b in the axial direction. More specifically, the curved shape of the rear grindstone 25 is from an opening grinding surface 25a for grinding the opening on the surface 5a of the plate glass 5 and an opening grinding surface 25c for grinding the opening on the back surface 5b of the plate glass 5. The curved surface gradually increases in diameter toward the inner grinding surface 25b that grinds the inner side from the opening of the plate glass 5, and the opening grinding surfaces 25a and 25c are inner grinding surfaces. 25b is formed in a chamfered concave portion of a curved surface with a continuous tangential inclination and a reduced diameter. Further, the rear grindstone portion 25 is formed in a continuous curved surface that is substantially symmetrical in the axial direction with the central portion of the inner grinding surface 25b in the axial direction of the shank 23 as the center.

  As shown in FIG. 11 (a), a curved grinding portion having opening grinding surfaces 25a and 25c as chamfered concave portions on both the upper and lower sides in the axial direction of the inner grinding surface 25b, and the plate glass 5 By providing an eccentric motion between them and grinding the inner peripheral surface of the grinding hole 27, as shown in FIG. 11 (b), the plate glass 5 has an inner peripheral surface along the inner grinding surface 25b and an opening. A grinding hole 27 having chamfered portions 27a and 27b utilizing the partially ground surfaces 25a and 25c can be formed. Moreover, since the inner peripheral surface of the grinding hole 27 has a chamfered portion 27a continuous with the surface 5a of the plate glass 5 and a chamfered portion 27b continuous with the back surface 5b of the plate glass 5, the stress due to the bending load is chamfered by the chamfered portions 27a and 27b. In addition to being able to escape in the tangential direction, the chamfer is chamfered, so that it is difficult to cause defects when the plate glass 5 is handled. In addition, since the back grindstone part 25 is formed in a larger diameter than the front-end grindstone part 24, the diamond drill 21 of a present Example is suitable for the use which forms the comparatively large diameter grinding hole 27. FIG. That is, by giving an eccentric motion between the rear grinding wheel portion 25 which is a curved surface bulging in the radial direction of the rotating shaft and the grinding hole 27 of the plate glass 5, the inner surface of the grinding hole 27 is formed into a larger-diameter curved surface. it can. Furthermore, the chamfered recesses do not necessarily need to be formed both above and below in the axial direction of the inner grinding surface 25b, which is a curved surface that bulges in the radial direction of the rotating shaft, but in the axial direction of the inner grinding surface 25b. It may be formed on at least one of the upper and lower sides.

  Next, a hole forming drill according to Example 3 will be described with reference to FIG. FIG. 12 is a side view showing the hole forming drill in the third embodiment of the present invention. In addition, the same structure as the said Example is abbreviate | omitted.

  FIG. 12 is a diamond drill 31 as a hole forming drill in the third embodiment, and the curved surface of the rear grindstone portion 35 as the curved grinding portion has the same curvature as the curved surface of the rear grindstone portion 15 in the first embodiment described above. It is formed in a curved surface, and by this drilling by the diamond drill 31, a grinding hole having a curved surface having the same shape as the grinding hole 17 shown in FIG. Moreover, the outer diameter of the back grindstone part 35 is formed smaller than the outer diameter of the front-end grindstone part 34 as a penetration grindstone part. By doing in this way, when the plate glass 5 is penetrated by the tip grindstone portion 34, the eccentric motion between the tip grindstone portion 34 and the plate glass 5 can be performed without performing the eccentric motion of the eccentric amount as in the first embodiment. The grinding hole 37 can be formed with 0 or slightly. Then, without contacting the inner peripheral surface of the grinding hole 37, the rear grindstone portion 35 can be easily moved relatively in the axial direction, and the curved surface portion can be formed on the plate glass 5 with a slight eccentric motion.

  In addition, since the back grindstone part 35 is formed in a smaller diameter than the front-end grindstone part 34, the diamond drill 31 of a present Example is suitable for the use which forms a comparatively small diameter grinding hole. Furthermore, the outer diameter of the rear grindstone portion 35 is not limited to a smaller diameter than the outer diameter of the tip grindstone portion 34, and may be formed to be approximately the same diameter as the outer diameter of the tip grindstone portion 34.

  Next, a hole forming drill according to Example 4 will be described with reference to FIG. FIG. 13 is a side view showing the hole forming drill in the fourth embodiment of the present invention. In addition, the same structure as the said Example is abbreviate | omitted.

  FIG. 13 is a diamond drill 41 as a hole forming drill in the fourth embodiment, and the curved surface of the rear grindstone portion 45 as the curved grinding portion has the same curvature as the curved surface of the rear grindstone portion 25 in the second embodiment. It is formed in a curved surface, and by this drilling by the diamond drill 41, a grinding hole having a curved surface having the same shape as the grinding hole 27 shown in FIG. Further, the outer diameter of the rear grindstone 45 is formed to be slightly smaller than the outer diameter of the tip grindstone 44 as a through grindstone. In this way, the tip grindstone portion 44 forms a grinding hole having an inner diameter that is the same as the outer diameter of the tip grindstone portion 44 in the plate glass without performing an eccentric amount of eccentric movement as in the first embodiment. It is easy to relatively move the rear grindstone portion 45 in the axial direction without making contact with the inner peripheral surface of the grinding hole, and the curved surface portion can be formed on the plate glass 5 with a slight eccentric motion.

  Since the rear grindstone 45 is formed with a smaller diameter than the tip grindstone 44, the diamond drill 41 of this embodiment is suitable for use in forming a relatively small diameter grinding hole. Furthermore, the outer diameter of the rear grindstone portion 45 is not limited to be smaller than the outer diameter of the tip grindstone portion 44, and may be formed to be substantially the same diameter as the outer diameter of the tip grindstone portion 44.

  Next, a hole forming drill according to Example 5 will be described with reference to FIGS. FIG. 14 is a side view showing the hole forming drill in the fifth embodiment of the present invention. FIG. 15A is a cross-sectional view showing a situation where the intermediate grindstone is ground as in FIG. 14, and FIG. 15B is a cross-sectional view showing a grinding hole of the plate glass after grinding. FIG. 19 is a graph showing the inclination angle of the tangent line at the position in the penetration direction of the grinding hole in Example 5. In addition, the same structure as the said Example is abbreviate | omitted.

  FIG. 14 is a diamond drill 51 as a hole forming drill in the fifth embodiment, and the grinding surface of the rear grindstone 55 is an abbreviation of the front surface 5a and the back surface 5b from the front surface 5a side of the plate glass 5 toward the inside. A grinding surface 55a that linearly extends in the axial direction to be ground to the middle, a grinding surface 55b as a curved grinding portion formed in a curved surface that is continuously reduced in diameter toward the axial direction ahead of the grinding surface 55a, The ground surface 55b is formed of a ground surface 55c that extends linearly in the axial direction and continues to the rear surface 5b of the glass sheet 5 continuously from the reduced diameter portion 55b ′ of the ground surface 55b.

  As shown in FIGS. 15A and 15B, by applying an eccentric motion between the rear grinding wheel portion 55 formed in this way and the plate glass 5, the grinding of the rear grinding stone portion 55 is performed on the plate glass 5. A grinding hole 57 having an inner peripheral surface shaped along the surfaces 55a, 55b and 55c is formed.

  As shown in FIG. 19, the inclination of the tangential line of the grinding hole 57 formed in the glass sheet 5 of this embodiment will be described. The inclination angle θ of the tangential line is the surface 5a (t of the glass sheet 5 ground by the grinding surface 55a. = 0) from the intermediate surface 5c (t = T / 2) to a constant π / 2, and the inclination angle θ is on the back surface 5b (t = T) side of the plate glass 5 ground by the grinding surface 55b. It increases continuously. Further, the inclination angle θ of the tangent line changes discontinuously in the portion to be ground (t = T1) ground at the reduced diameter portion 55b ′, and the back surface 5b (t = T) from the portion to be ground (t = T1). Up to a constant π / 2.

  Next, a hole forming drill according to Example 6 will be described with reference to FIGS. FIG. 16: is a side view which shows the drill for hole formation in Example 6 of this invention. FIG. 17A is a cross-sectional view showing a situation where the intermediate grindstone is ground as in FIG. 16, and FIG. 17B is a cross-sectional view showing a grinding hole of the plate glass after grinding. In addition, the same structure as the said Example is abbreviate | omitted.

  FIG. 16 shows a diamond drill 61 as a hole forming drill in the sixth embodiment, and a rear grindstone portion 65 as a curved grinding portion is contracted in a radial direction of the rotation shaft more than a tip grindstone portion 64 as a through grindstone portion. It is a curved surface with a diameter. More specifically, the rear grindstone portion 65 is a curved surface in which the tangential inclination continues along the axial direction of the shank 63, and the opening grinding surface 65 a for grinding the surface 5 a of the plate glass 5 and the back surface 5 b of the plate glass 5. Is a curved surface that gradually decreases in diameter toward the inner portion grinding surface 65b that grinds the inner side of the glass sheet 5 in the axial direction relative to the opening grinding surface 65c that grinds, and the grinding surface in the axial direction of the shank 63 A continuous curved surface that is substantially symmetric in the axial direction is provided around a central portion located in the middle of 65b.

  As shown in FIGS. 17 (a) and 17 (b), by giving an eccentric motion between the rear grinding wheel portion 65, which is a curved surface reduced in diameter in the radial direction of the rotating shaft, and the plate glass 5, A grinding hole 67 having a shape along the inner grinding surface 65b can be formed. In addition, since the back grindstone part 65 is formed in a smaller diameter than the front-end grindstone part 64, the diamond drill 61 of a present Example is suitable for the use which forms a comparatively small diameter grinding hole.

  Further, the rear grindstone portion 65 is formed in a curved surface having only a uniform curvature along the penetrating direction, and the inclination of the tangent line is inclined on the inner peripheral surface of the grinding hole 67 of the plate glass 5 formed by the rear grindstone portion 65. Since it is uniformly continuous, the stress due to the bending load can be evenly dispersed.

  Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and modifications and additions within the scope of the present invention are included in the present invention. It is.

  For example, in the above embodiment, it is possible to form an inner peripheral surface with a continuous tangential slope on the hard and brittle material plate by the rear grindstone, but the continuous tangential slope is shown in FIG. ), As shown in (b), it may change continuously over the penetration direction of the hard and brittle material plate, as shown in FIGS. 15 (b) and 19 in the fifth embodiment. Moreover, you may have a part which changes continuously only in a part along the penetration direction of a hard-brittle material board. Further, the cross-sectional view shape of the curved surface of the inner peripheral surface is not necessarily limited to the present embodiment, and may be, for example, a substantially sine curve in a cross-sectional view, or the curved surface shape is a substantially quadratic curve in a cross-sectional view, for example. As shown in FIG. 20, the slope of the tangent may be increased or decreased linearly, that is, the slope of the tangent may be expressed by a linear expression. In other words, a curved surface having a tangent slope that is continuous is a face excluding a face having a constant tangent slope. Here, the surface where the inclination of the tangent is constant is, for example, as shown in FIG. 21A, the inner peripheral surface of the grinding hole 87 as the inner peripheral surface of the plate glass 5 is orthogonal to the front and back surfaces of the plate glass 5. An inner peripheral surface 87b formed in a direction to be cut, a chamfered portion 87a formed on the plate glass surface 5a side of the inner peripheral surface 87b, and a chamfered portion 87c formed on the plate glass back surface 5b side of the inner peripheral surface 87b. As shown in FIG. 21B, the tangential inclination angle θ (vertical axis) is relative to the position t (horizontal axis) in the penetrating direction of the grinding hole 87, as shown in FIG. , Shown in parallel.

  Moreover, in the said Example, the plate glass 5 in the plasma display panel 1 is shown as an application example of the hard-brittle material board provided with the through-hole, and the grinding hole for distribute | circulating the noble gas enclosed inside as the said through-hole is shown. However, for example, the material of the hard and brittle material plate may be a resin material or the like, and for example, the use of the through hole provided in the hard and brittle material plate is an insertion hole or the like for inserting a screw member. Also good.

  Further, in the above embodiment, the diamond drill as the hole forming drill includes the tip grindstone portion as the penetrating grindstone portion and the rear grindstone portion as the curved grinding portion, and using the tip grindstone portion of this diamond drill, A through-hole is opened in the brittle material plate and a curved surface is formed on the inner peripheral surface of the through-hole using a curved grinding part. For example, a through-hole having a linear inner peripheral surface formed in the penetration direction has already been formed. The hard and brittle material may be present, and finish processing may be performed by forming the inner peripheral surface of the through hole of the hard and brittle material into a curved surface using a diamond drill having only a curved grinding portion. Further, for example, a through hole is formed in a hard and brittle material using a drill having only a through grindstone portion, and an inner peripheral surface of the through hole is formed by using a diamond drill having only a curved grinding portion separately from this drill. Finishing may be performed by forming a curved surface.

It is a schematic perspective view which shows the example of application of the hard-brittle material board which concerns on this invention. It is a perspective view which shows the drill for hole formation in Example 1 of this invention. FIG. 3 is a front view similar to FIG. 2. FIG. 3 is a side view similar to FIG. 2. FIG. 3 is a sectional side view similar to FIG. 2. It is sectional drawing which shows the condition which perforates plate glass similarly to FIG. It is AA sectional drawing of FIG. (A) is sectional drawing which shows the condition which penetrated the plate glass similarly to FIG. 2, (b) is sectional drawing which shows the condition ground with an intermediate grindstone part. (A) is sectional drawing which shows the grinding hole of the plate glass after grinding similarly to FIG. 2, (b) is sectional drawing which shows the condition where the bending load was applied to plate glass. It is a side view which shows the drill for hole formation in Example 2 of this invention. (A) is sectional drawing which shows the condition ground with an intermediate grindstone part similarly to FIG. 10, (b) is sectional drawing which shows the grinding hole of the plate glass after grinding. It is a side view which shows the drill for hole formation in Example 3 of this invention. It is a side view which shows the drill for hole formation in Example 4 of this invention. It is a side view which shows the drill for hole formation in Example 5 of this invention. (A) is sectional drawing which shows the condition ground with an intermediate grindstone part similarly to FIG. 14, (b) is sectional drawing which shows the grinding hole of the plate glass after grinding. It is a side view which shows the drill for hole formation in Example 6 of this invention. (A) is sectional drawing which shows the condition ground with an intermediate grindstone part similarly to FIG. 16, (b) is sectional drawing which shows the grinding hole of the plate glass after grinding. (A) is the figure which illustrated the inclination angle of the tangent in the position of the penetration direction of a grinding hole in Example 1, (b) is a graph which shows the inclination angle of the tangent in the position of the penetration direction of a grinding hole. . In Example 5, it is a graph which shows the inclination-angle of the tangent in the position of the penetration direction of a grinding hole. It is a graph which shows the inclination angle of the tangent in the position of the penetration direction of the grinding hole formed in a cross sectional view substantially quadratic curve. (A) is sectional drawing which shows the grinding hole formed in the linear form which cross-sectional view of plate glass continued. (B) is a graph which shows the inclination angle of the tangent in the position of the penetration direction of a grinding hole.

Explanation of symbols

1 Plasma display panel 5 Flat glass (hard brittle material plate)
5a Front surface 5b Back surface 5c Intermediate surface 11 Diamond drill (drill for forming holes)
12 Diamond grinding wheel (grinding wheel)
13 Shank 14 Tip whetstone (penetrating whetstone)
14c Front end surface 15 Rear grinding wheel (curved surface)
15a Opening grinding surface 15b Inner grinding surface 15c Opening grinding surface 17 Grinding hole 21 Diamond drill 25 Rear grinding wheel (curved grinding part)
25a Grinding surface of the opening (chamfered recess)
25b Inner part grinding surface 25c Opening part grinding surface (chamfered recess)
27 Grinding hole 31 Diamond drill 34 Tip grindstone (through grindstone)
35 Rear wheel (curved surface)
41 Diamond drill 44 Tip grindstone (through grindstone)
45 Back wheel (curved surface)
51 Diamond drill 55 Back grinding wheel portion 55b Grinding surface (curved surface grinding portion)
57 Grinding hole 61 Diamond drill 65 Back grinding wheel part (curved surface grinding part)
65b Inner part grinding surface 67 Grinding hole 71 Diamond drill 75 Rear grinding wheel parts 75a, 75c Chamfered part grinding surface (curved surface grinding part)
77 Grinding hole 87 Grinding hole

Claims (4)

A grindstone portion is provided along the axial direction on the peripheral surface of the shank acting as a rotating shaft, the grindstone portion is disposed in a through-hole of a hard and brittle material plate to be ground , and the grindstone portion is disposed on the shaft center of the shank. by providing an eccentric motion between to pivot Rutotomoni the through hole as the center, a hole forming drill grinding an inner surface of the through hole,
The grindstone portion has a curved grinding portion formed of a curved surface having a tangential slope continuous along the axial direction of the rotating shaft, and the curved grinding portion bulges so that the tangential slope continuously increases. The bulging curved surface is disposed in the through hole when the inner surface of the through hole is ground, and the curved grinding portion is a hard and brittle material to be ground. A drill for forming holes, characterized by having a length equal to or greater than the thickness of the plate . 2. The drill for forming a hole according to claim 1 , wherein the curved grinding portion has a chamfered recess formed of a curved surface that is continuous with the bulging curved surface and has a diameter reduced in a radial direction of a rotation shaft. . The grindstone portion includes a penetrating grindstone portion that is provided on the front end side and penetrates a hard and brittle material plate, and the curved grinding portion that is provided on the rear side of the penetrating grindstone portion. The hole forming drill according to claim 1 or 2 . The hole forming drill according to claim 3 , wherein an outer diameter of the curved grinding portion is formed to be substantially the same as or smaller than an outer diameter of the penetrating grindstone portion.

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