JP2009125908A - Grinding wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinding wheel that can vibrate a grindstone with sufficient amplitude in an intended direction by using ultrasonic vibration generated by an ultrasonic vibrator. <P>SOLUTION: A grinding wheel mounting portion 512 comprising the grindstone 52 and the ultrasonic vibrator 6 has such a structure that a plurality of hole-shaped relief portions 513 is formed discretely in the circumferential direction penetrating the grinding wheel mounting portion 512 in the thickness direction orthogonal to a vibration direction (radial direction) of the ultrasonic vibration by the ultrasonic vibrator 6 and elongated in the radial direction. According to the structure, the plurality of hole-shaped relief portions 513 serves a waveform shaping function so as to cancel deflection caused by vibration in the circumferential direction other than vibration in an intended vibration direction of the ultrasonic vibration, and therefore, the grindstones 52 can be vibrated with sufficient amplitude in the intended radial direction by the ultrasonic vibration generated by the ultrasonic vibrator 6. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel base attached to a wheel mount provided at one end of a rotary spindle constituting a grinding means for grinding a workpiece held on a chuck table, and an annular shape attached to the wheel base. The present invention relates to a grinding wheel that is composed of a grinding wheel and generates ultrasonic vibration during grinding.

  In the semiconductor device manufacturing process, a plurality of regions are defined by dividing lines called streets arranged in a lattice pattern on the surface of a substantially wafer-shaped semiconductor wafer, and ICs, LSIs, etc. are defined in these partitioned regions. Form a device. Then, the semiconductor wafer is cut along a street with a cutting blade in which abrasive grains are hardened with bonds to divide the region where the device is formed to manufacture individual semiconductor chips.

  However, for difficult-to-cut materials such as brittle materials such as sapphire and SiC, semiconductor packages such as QFN, and tough materials such as metal substrates, clogging of abrasive grains and heat generation near the processing point can be achieved simply by cutting the cutting blade. There is a problem that cutting is not performed smoothly due to the influence of the above. Therefore, the cutting blade is vibrated in the radial direction by an ultrasonic vibrator, and cutting, grooving, and the like are performed using the radial vibration along with the rotation of the cutting blade (see, for example, Patent Document 1). ).

  Such a situation is the same in the grinding apparatus. That is, the wafer divided as described above is ground to the predetermined thickness by the grinding device before being cut along the street. When the back surface of the wafer is ground by the grinding wheel of the grinding device, the grinding ability is reduced due to the clogging of the grinding wheel and the contamination discharge not smoothly. In particular, when a brittle hard material such as sapphire, silicon nitride, lithium tantalate, or altic is ground, there is a problem that productivity is remarkably lowered due to a decrease in grinding ability due to clogging of a grinding wheel.

  In order to solve such a problem, at least one of a chuck table that holds a workpiece and a grindstone holding member that holds a grinding wheel that grinds the workpiece held on the chuck table is provided with a grinding wheel. There has been proposed a grinding apparatus in which ultrasonic application means for applying ultrasonic vibration is provided to a grinding portion of a workpiece (see, for example, Patent Document 2). At this time, in Patent Document 2, the ultrasonic application means is disposed on the chuck table side, but by using the technique disclosed in Patent Document 1, the ultrasonic application means is disposed on the grindstone holding member side. Can be assumed.

JP 2004-291636 A JP-A-2-232164

  However, in the technique disclosed in Patent Document 1, particularly in a grinding wheel having a large diameter of 8 inches or more, unnecessary vibrations are generated other than in a desired direction. As a result, there is a problem that even if ultrasonic vibration is applied, the grinding wheel cannot be vibrated with sufficient amplitude in a desired direction, and difficult-to-cut materials cannot be ground smoothly.

  The present invention has been made in view of the above, and an object of the present invention is to provide a grinding wheel that can vibrate a grinding wheel with sufficient amplitude in a desired direction by ultrasonic vibration generated by an ultrasonic vibrator. And

  In order to solve the above-described problems and achieve the object, a grinding wheel according to the present invention is provided on a wheel mount provided at one end of a rotary spindle that constitutes a grinding means for grinding a workpiece held on a chuck table. A grinding wheel that includes a wheel base to be attached and an annular grinding wheel mounted on the wheel base and generates ultrasonic vibration during grinding. The wheel base is a circle connected to the wheel mount. An annular connecting portion, and an annular grindstone mounting portion connected to the lower end of the connecting portion with the wheel mount side as an upper surface, the grindstone mounting portion, the grinding wheel mounted on the lower surface side, An ultrasonic vibrator that generates ultrasonic vibrations, penetrating the grinding wheel mounting portion in a direction perpendicular to the vibration direction of the ultrasonic vibrations by the ultrasonic vibrators, and A plurality of hole-like relief portions that are elongated in the moving direction are discretely provided in the circumferential direction, and the connection portion has an elastic connection structure that does not hinder the vibration of the grindstone mounting portion by the ultrasonic vibrator. It is characterized by that.

  In the grinding wheel according to the present invention, in the above invention, the ultrasonic vibrator is mounted so as to generate ultrasonic vibration in a radial direction with respect to the grindstone mounting portion, and the hole-shaped escape portion is formed of the grindstone. It is characterized in that it is formed so as to penetrate in the thickness direction of the mounting portion and to be elongated in the radial direction.

  In the grinding wheel according to the present invention, in the above invention, the ultrasonic vibrator is mounted so as to generate ultrasonic vibration in a thickness direction with respect to the grindstone mounting portion, and the hole-shaped relief portion is formed of the grindstone. It is characterized in that it is formed so as to penetrate in the radial direction of the mounting portion and to be elongated in the thickness direction.

  In the grinding wheel according to the present invention, in the above invention, the connecting portion is elastic in the radial direction and the thickness direction by forming at least one annular groove on the outer peripheral surface or inner peripheral surface of the annular connecting portion. It has the characteristic elastic connection structure.

  Further, in the grinding wheel according to the present invention, in the above invention, the connecting portion is elastic in the thickness direction by forming a plurality of through holes extending in the radial direction of the annular connecting portion in the circumferential direction. It has an elastic connection structure.

  The grinding wheel according to the present invention is characterized in that, in the above invention, the hole-shaped relief portion is formed of a long and narrow slit hole in a vibration direction.

  The grinding wheel according to the present invention is characterized in that, in the above-mentioned invention, the hole-shaped relief portions are formed to be uniformly dispersed in a circumferential direction of the grindstone mounting portion.

  In the grinding wheel according to the present invention, a grindstone mounting portion having a grinding grindstone and an ultrasonic vibrator penetrates the grindstone mounting portion in a direction perpendicular to the vibration direction of the ultrasonic vibration generated by the ultrasonic vibrator. Since a plurality of hole-like relief portions that are elongated in the vibration direction are discretely provided in the circumferential direction, the plurality of hole-like reliefs are canceled so as to cancel the bending due to vibrations in the circumferential direction other than the desired vibration direction of ultrasonic vibration. The part functions as a wave, and the grinding wheel can be vibrated with sufficient amplitude in the desired direction by the ultrasonic vibration generated by the ultrasonic vibrator. Even when the grinding wheel is enlarged, it is suitable. The effect that it can respond to is produced.

  Hereinafter, a grinding wheel which is the best mode for carrying out the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a perspective view showing a configuration example of the entire grinding apparatus including the grinding wheel according to the first embodiment, and FIG. 2 is a longitudinal side view of a spindle unit included in the grinding apparatus that also shows an electrical equipment control system. is there. The grinding apparatus according to the first embodiment includes an apparatus housing 2. The apparatus housing 2 has a rectangular parallelepiped main portion 21 extending elongated and a pair of upright walls 22 provided at a rear end portion (upper right end in FIG. 1) of the main portion 21 and extending substantially vertically. A pair of guide rails 221 extending in the vertical direction are provided on the front surface of the upright wall 22. The grinding means 3 is mounted on the pair of guide rails 221 so as to be movable in the vertical direction.

  The grinding means 3 includes a moving base 31 and a spindle unit 4 mounted on the moving base 31. The movable base 31 is provided with a pair of leg portions 311 extending in the vertical direction on both sides of the rear surface, and a guide groove 312 that slidably engages with the pair of guide rails 221 is formed on the pair of leg portions 311. Yes. A support portion 313 protruding forward is provided on the front surface of the moving base 31, and the spindle unit 4 is attached to the support portion 313.

  The spindle unit 4 includes a spindle housing 41 mounted on the support portion 313 and a rotating spindle 42 that is rotatably disposed on the spindle housing 41. Here, as shown in FIG. 2, the spindle housing 41 is formed in a substantially cylindrical shape and includes a shaft hole 411 penetrating in the axial direction. A rotating spindle 42 that is inserted through a shaft hole 411 formed in the spindle housing 41 is provided with a thrust bearing flange 421 that is formed to protrude in the radial direction at the center thereof. Thereby, the rotary spindle 42 is rotatably supported by high-pressure air supplied between the inner wall of the shaft hole 411. One end of the rotary spindle 42 (the lower end in FIG. 2) is disposed so as to protrude from the lower end of the spindle housing 41, and a wheel mount 43 is provided at one end thereof. The grinding wheel 5 according to the first embodiment is attached to the lower surface of the wheel mount 43. The grinding wheel 5 will be described later.

  Further, the grinding apparatus includes a grinding unit feed mechanism 10 that moves the spindle unit 4 in the vertical direction along the pair of guide rails 221. The grinding unit feed mechanism 10 includes a male screw rod 101 disposed on the front side of the upright wall 22 and extending substantially vertically. The male screw rod 101 is rotatably supported by bearing members 102 and 103 whose upper end and lower end are attached to the upright wall 22. The upper bearing member 102 is provided with a pulse motor 104 that rotationally drives the male screw rod 101. A through female screw hole (not shown) extending rearward from the center in the width direction is formed on the rear surface of the movable base 31, and the male screw rod 101 is screwed into the through female screw hole. Therefore, when the pulse motor 104 rotates in the forward direction, the moving base 31, that is, the grinding means 3 moves down (forwards), and when the pulse motor 104 rotates in the reverse direction, the moving base 31, that is, the grinding means 3 moves up (retracts).

  The chuck table mechanism 11 is disposed in the main portion 21 of the housing 2. The chuck table mechanism 11 includes a chuck table 12, a cover member 13 that covers the periphery of the chuck table 12, and bellows means 14 and 15 disposed before and after the cover member 13. The chuck table 12 is rotated by a rotating means (not shown), and is configured to suck and hold the workpiece W on its upper surface by operating a suction means (not shown). Further, the chuck table 12 is moved between a workpiece placement area 24 shown in FIG. 1 and a grinding area 25 facing the grinding wheel 5 constituting the spindle unit 4 by a chuck table moving means (not shown). The The bellows means 14 and 15 are made of an appropriate material such as a campus cloth. The front end of the bellows means 14 is fixed to the front wall of the main portion 21, and the rear end is fixed to the front end surface of the cover member 13. The front end of the bellows means 15 is fixed to the rear end surface of the cover member 13, and the rear end is fixed to the front surface of the upright wall 22 of the apparatus housing 2. When the chuck table 12 moves in the direction indicated by the arrow 23a, the bellows means 14 expands and the bellows means 15 contracts. Conversely, when the chuck table 12 moves in the direction indicated by the arrow 23b, the bellows means 14 moves. The bellows means 15 contracts and expands.

  Next, the grinding wheel 5 of the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is an exploded perspective view showing the grinding wheel, and FIG. 4 is a sectional view of a part of the connecting portion. The grinding wheel 5 of the first embodiment has a large diameter of, for example, 8 inches or more, and is mounted so as to form an annular shape on a wheel base 51 attached to the wheel mount 43 and a lower surface of the wheel base 51. And a plurality of grinding wheels 52 to be used. The wheel base 51 is formed in a size corresponding to the wheel mount 43 and is connected to an annular connecting portion 511 for connecting to the wheel mount 43 and to the lower end portion of the connecting portion 511 with the wheel mount 43 side as an upper surface. And an annular grindstone mounting portion 512.

  The upper side of the connecting portion 511 is fixed to the wheel mount 43 and becomes the restraint side, and a plurality of screw holes 511a corresponding to a plurality of bolt insertion holes (not shown) formed in the wheel mount 43 are formed. . Further, as shown in the cross-sectional view of FIG. 4, a plurality of slit-like annular grooves 511b are alternately bitingly formed on the outer peripheral surface and the inner peripheral surface on the lower side of the connecting portion 511 to which the grindstone mounting portion 512 is fixed. Thus, an elastic coupling structure that has elasticity in the radial direction and the thickness direction so as not to hinder vibration of the grindstone mounting portion 512 by an ultrasonic vibrator, which will be described later, and insulates vibrations from the upper restraint portion side It is configured as.

  The grindstone mounting portion 512 has an opening 512a formed at the center and is formed in an annular shape as a whole, but the size of the opening 512a may be any size as long as it can be inserted with wiring, and is small. May be. At a position near the outer periphery on the lower surface side of such a grindstone mounting portion 512, a plurality of grinding wheels 52 are mounted so as to form an annular shape with an adhesive appropriately in the circumferential direction. One grinding wheel formed in an annular shape may be used.

  Further, in the grindstone mounting portion 512, for example, at positions on the inner peripheral side with respect to the grinding grindstone 52 and on both upper and lower double-sided positions concentric with the grindstone 52 arranged in an annular shape around the center of the grinding wheel 5, An annular ultrasonic transducer 6 mounted with an adhesive is provided. These ultrasonic vibrators 6 are for applying ultrasonic vibration to the grinding wheel 52 via the grinding wheel mounting portion 512, and examples thereof include barium titanate, lead zirconate titanate (PZT), and lithium tantalate. It is made of piezoelectric ceramics. As the ultrasonic transducer 6 of the first embodiment, for example, a PZT transducer is used. The target vibration direction of the ultrasonic transducer 6 is set to be the radial direction of the grindstone mounting portion 512. In this way, one end of the conductive wire 61 is connected to the + and − terminals on the front and back surfaces of the ultrasonic transducer 6 mounted on the upper and lower surfaces of the grindstone mounting portion 512. The conductive wire 61 is connected to the + and − terminals of the ultrasonic transducer 6 on the lower surface side through the opening 512a. The other end of the conductive wire 61 is connected to a convex connector (not shown). This convex connector is detachably connected to a power supply means described later.

  Further, in the grindstone mounting portion 512, a plurality of hole-like relief portions 513 penetrating in the vertical thickness direction, which is a direction orthogonal to the vibration direction of the ultrasonic transducer 6 and the circumferential direction, are discretely formed in the circumferential direction. Has been. These hole-shaped escape portions 513 are formed of elongated linear slit holes that are continuous in the radial direction, which is a desired vibration direction, and are formed in a cutout shape on the outer peripheral side. The inner peripheral side of the hole-shaped escape portion 513 is formed, for example, up to a position that is more than half the width of the grindstone mounting portion 512. Further, the number of hole-shaped relief portions 513 is appropriately formed in the circumferential direction of the grindstone mounting portion 512, but the number of portions surrounded by the hole-shaped relief portions 513 is preferably as close to a rectangular shape as possible, It is preferable to form them uniformly dispersed in the circumferential direction.

  The grinding wheel 5 configured as described above is detachably mounted on the mount wheel 43 by screwing the fastening bolts 55 respectively inserted through the bolt insertion holes formed in the wheel mount 43 into the screw holes 511a. The

  Returning to FIG. 2 and continuing the description, the spindle unit 4 includes an electric motor 7 for driving the rotary spindle 42 to rotate. The electric motor 7 is, for example, a permanent magnet type motor, and includes a rotor 71 made of a permanent magnet mounted on a motor mounting portion 422 formed at an intermediate portion of the rotary spindle 42, and a spindle housing on the outer peripheral side of the rotor 71. 41 and a stator coil 72 disposed on 41. In the electric motor 7, the rotor 71 rotates when AC power is supplied to the stator coil 72 by power supply means described later, and the rotating spindle 42 on which the rotor 71 is mounted rotates.

  Further, the spindle unit 4 includes power supply means 8 for supplying AC power to the ultrasonic transducer 6 and supplying AC power to the electric motor 7. The power supply means 8 includes a rotary transformer 80 disposed at the rear end of the spindle unit 4. The rotary transformer 80 includes a power receiving unit 81 disposed at the rear end of the rotary spindle 42 and a power feeding unit 82 disposed opposite to the power receiving unit 81 and disposed at the rear end portion of the spindle housing 41. is doing. The power receiving means 81 includes a rotor side core 811 attached to the rotary spindle 42 and a power receiving coil 812 wound around the rotor side core 811. A conductive wire 813 is connected to the power receiving coil 812. The conductive wire 813 is disposed in a hole 423 formed in the axial direction at the center of the rotary spindle 42, and the tip thereof is connected to a concave connector (not shown) that fits with a convex connector (not shown). The power feeding means 82 includes a stator side core 821 disposed on the outer peripheral side of the power receiving means 81 and a power feeding coil 822 disposed on the stator side core 821. AC power is supplied to the power supply coil 822 via the wiring 83.

  The power supply unit 8 includes an AC power supply 91 for AC power supplied to the power supply coil 822 of the rotary transformer 80, a voltage adjustment unit 92, and a frequency adjustment unit 93 for adjusting the frequency of AC power supplied to the power supply unit 82. A control means 94 for controlling the voltage adjustment means 92 and the frequency adjustment means 93; and an input means 95 for inputting the amplitude of the ultrasonic vibration of the ultrasonic vibrator 6 applied to the plurality of grinding wheels 52 to the control means 94. It has. The power supply unit 8 supplies AC power to the stator coil 72 of the electric motor 7 via the control circuit 96 and the wiring 721.

  Here, the operation of the spindle unit 4 will be described. When performing the grinding operation, AC power is supplied from the power supply means 8 to the stator coil 72 of the electric motor 7. As a result, the electric motor 7 rotates and the rotating spindle 42 rotates, and the grinding wheel 5 attached to the tip of the rotating spindle 42 rotates.

  On the other hand, the power supply means 8 controls the voltage adjusting means 92 and the frequency adjusting means 93 by the control means 94 to control the voltage of the AC power to a predetermined voltage, and converts the frequency of the AC power to a predetermined frequency, thereby rotating the rotary power. The power is supplied to the power supply coil 822 of the power supply means 82 constituting the transformer 80. When AC power having a predetermined frequency and a predetermined voltage is supplied to the feeding coil 822, an annular ultrasonic wave is passed through the power receiving coil 812 of the rotating power receiving means 81, the conductive wire 813, the concave connector, the convex connector, and the conductive wire 61. AC power having a predetermined voltage and a predetermined frequency is applied to the vibrator 6. As a result, the ultrasonic transducer 6 vibrates ultrasonically in the radial direction. The ultrasonic vibration generated by the ultrasonic vibrator 6 is transmitted to the plurality of grinding wheels 52 via the grinding wheel mounting portion 512.

  Next, the operation of the grinding apparatus according to the first embodiment will be described. First, as shown in FIG. 1, a workpiece W to be ground, such as a semiconductor wafer, is placed on the chuck table 12 positioned in the workpiece placement area 24 of the grinding apparatus. When the workpiece W is a semiconductor wafer, a protective tape T is stuck on the surface on which the device is formed, and the protective tape T side is placed on the chuck table 12. The workpiece W placed on the chuck table 12 is sucked and held on the chuck table 12 by suction means (not shown). Then, the chuck table moving means (not shown) is operated to move the chuck table 12 in the direction indicated by the arrow 23 a and to be positioned in the grinding area 25. Then, the outer peripheral edge of the grinding wheel 52 in the grinding wheel 5 is positioned so as to pass the rotation center of the chuck table 12 (that is, the center of the workpiece W).

  After being positioned in such a positional relationship, the chuck table 12 is rotated at a rotational speed of, for example, 300 rpm, and the grinding wheel 5 is rotated in the same direction at a rotational speed of, for example, 6000 rpm. That is, by supplying AC power from the power supply means 8 to the stator coil 72, the electric motor 7 rotates and the rotating spindle 42 rotates, and the rotating wheel 5 attached to the tip of the rotating spindle 42 rotates. Then, the grinding wheel 5 is lowered to press the grinding wheel 52 against the back surface (surface to be ground), which is the top surface of the workpiece W, with a predetermined pressure. As a result, the surface to be ground of the workpiece W is ground over the entire surface. At this time, the grinding fluid is supplied to the grinding portion by the plurality of grinding wheels 52.

  At the time of such grinding, AC power having a predetermined voltage and a predetermined frequency is supplied to the power supply coil 822 of the power supply unit 82 constituting the rotary transformer 80 by the power supply unit 8. As a result, AC power having a predetermined voltage and a predetermined frequency is applied to the ultrasonic transducer 6 via the power receiving coil 812, the conductive wire 813, the concave connector, the convex connector, and the conductive wire 61 of the rotating power receiving means 81. As a result, the ultrasonic vibrator 6 is ultrasonically vibrated by being repeatedly displaced in the radial direction. This ultrasonic vibration is transmitted to the plurality of grinding wheels 52 via the grinding wheel mounting portion 512, and the plurality of grinding wheels 52 are ultrasonically vibrated in the radial direction.

  At this time, as in the first embodiment, in the case of the grinding wheel 5 having a large diameter, the ultrasonic vibration generated by the ultrasonic vibrator 6 is only in the radial direction of the grindstone mounting portion 512 which is a desired vibration direction. In addition, unnecessary vibration is also generated in the circumferential direction of the grindstone mounting portion 512, and bending is caused in the circumferential direction. Accordingly, even if ultrasonic vibration is applied, the grinding wheel 52 cannot be vibrated with a sufficient amplitude in a desired radial direction, and the difficult-to-cut material cannot be smoothly ground. The larger the diameter of the grinding wheel 5, the more pronounced it becomes.

  Here, in the first embodiment, the grindstone mounting portion 512 has discrete holes 513 formed by a plurality of slit holes penetrating in the thickness direction and elongated in the radial direction in the circumferential direction. The bending due to the vibration in the circumferential direction other than the desired vibration direction of the sonic vibration is canceled out. That is, the plurality of hole-shaped escape portions 513 perform a wave-matching function so that the vibration of the ultrasonic vibrator 6 is generated only in a desired radial direction. Therefore, the grinding wheel 52 can be vibrated with sufficient amplitude in a desired radial direction by the ultrasonic vibration generated by the ultrasonic vibrator 6, and the difficult-to-cut material can be ground smoothly.

  In such a grinding operation, the grindstone mounting portion 512 of the grinding wheel 5 and the wheel mount 43 are coupled via a coupling portion 511 having an elastic coupling structure, and the grinding wheel mounting portion 512 is vibrated in the radial direction. Since the lower side of the connecting portion 511 in which the annular groove 511b is formed follows and elastically displaces in the radial direction, the ultrasonic vibration is not hindered. At the same time, since the upper side of the connecting portion 511 is fixed to the wheel mount 43 so as to be a restraining portion, the ultrasonic vibration is insulated so as not to be transmitted to the wheel mount 43 side.

(Modification)
FIG. 5 is a perspective view of a grinding wheel 5 showing a modification of the first embodiment. In this modification, instead of the ultrasonic transducer 6 formed in an annular shape, a plurality of ultrasonic transducers 6 </ b> A formed in an arc shape are mounted so as to form an annular shape on both upper and lower surfaces of the grindstone mounting portion 512. The vibration direction of the ultrasonic vibration is set to be the radial direction of the grindstone mounting portion 512. Further, in this modified example, instead of the hole-like relief portion 513 formed by the slit hole having a notch shape on the outer peripheral side, a hole formed by a plurality of slit holes penetrated in the thickness direction within the width of the inner and outer periphery of the grindstone mounting portion 512. A shaped relief portion 514 is formed.

  In the case of this modification, the same effects as in the case of the first embodiment are obtained. In the first embodiment, the hole-shaped escape portion 514 may be formed, or in the present modification, the hole-shaped escape portion 513 may be formed.

(Embodiment 2)
FIG. 6 is an exploded perspective view showing the grinding wheel of the second embodiment. The wheel base 51A of the grinding wheel 5A according to the second embodiment is formed in a size corresponding to the wheel mount 43 and has an annular connecting portion 521 for connecting to the wheel mount 43, and the wheel mount 43 side on the upper surface. And an annular grindstone mounting portion 522 connected to the lower end portion of the connecting portion 521.

  The upper side of the connecting portion 521 is fixed to the wheel mount 43 and becomes the restraint side, and a plurality of screw holes 521a corresponding to a plurality of bolt insertion holes (not shown) formed in the wheel mount 43 are formed. . In addition, the lower side of the connecting portion 521 to which the grindstone mounting portion 522 is fixed is formed with a plurality of through holes 521b extending in the radial direction that are elongated in the circumferential direction. It has elasticity in the thickness direction so as not to hinder the vibration of 522, and is configured as an elastic connection structure that insulates vibration with the upper restraint portion side. Here, the through holes 521b are easily deformed, for example, by being alternately formed in two stages.

  The grindstone mounting portion 522 is formed in an annular shape as a whole with a large opening 522a formed at the center. At a position near the outer periphery on the lower surface side of such a grindstone mounting portion 522, a plurality of grinding grindstones 52 are mounted so as to form an annular shape with an adhesive appropriately in the circumferential direction. One grinding wheel formed in an annular shape may be used.

  Further, in the grindstone mounting portion 522, a plurality of ultrasonic transducers 6B mounted with an appropriate adhesive are disposed on the outer peripheral surface. These ultrasonic vibrators 6 </ b> B are for applying ultrasonic vibration to the grinding wheel 52 via the grinding wheel mounting portion 522. Here, the target vibration direction of the ultrasonic transducer 6 </ b> B is set to be the thickness direction of the grindstone mounting portion 522.

  Further, in the grindstone mounting portion 522, a plurality of hole-like relief portions 523 penetrating in the radial direction that is a direction orthogonal to the vibration direction of the ultrasonic transducer 6B and the circumferential direction are discretely formed in the circumferential direction. ing. These hole-shaped escape portions 523 are formed of elongated slits that are continuous in the thickness direction, which is a desired vibration direction. The slit length of the hole-shaped escape portion 523 is, for example, a length that is at least half the thickness of the grindstone mounting portion 522. Further, the number of the hole-shaped escape portions 523 is appropriately formed in the circumferential direction of the grindstone mounting portion 522, but the number of the portions surrounded by the hole-shaped escape portions 523 is preferably as close to a rectangular shape as possible. It is preferable to form them uniformly dispersed in the circumferential direction. It should be noted that the hole-like relief portion 523 may be formed in a notch shape on the lower end side, as in the case of the hole-like relief portion 513.

  The grinding wheel 5A configured as described above is detachably mounted on the mount wheel 43 by screwing the fastening bolts 55 respectively inserted through the bolt insertion holes formed in the wheel mount 43 into the screw holes 521a. The

  In the case of the grinding wheel 5A having a large diameter as in the second embodiment, the ultrasonic vibration generated by the ultrasonic vibrator 6B is not only in the thickness direction of the grindstone mounting portion 512, which is a desired vibration direction. Unnecessary vibration is also generated in the circumferential direction of the grindstone mounting portion 522, and the inner and outer peripheral surfaces are bent in the circumferential direction. As a result, even if ultrasonic vibration is applied, the grinding wheel 52 cannot be vibrated with sufficient amplitude in the desired thickness direction, and difficult-to-cut materials cannot be ground smoothly. The larger the diameter of the grinding wheel 5A, the more prominent. Moreover, it becomes more remarkable as the thickness of the grinding wheel 5A increases.

  Here, in the second embodiment, the grindstone mounting portion 522 has the hole-like relief portions 523 formed by a plurality of slit holes penetrating in the radial direction and elongated in the thickness direction in the circumferential direction. The bending due to the vibration in the circumferential direction other than the desired vibration direction of the sonic vibration is canceled out. That is, the plurality of hole-shaped escape portions 513 perform a wave-matching function so that the vibration of the ultrasonic transducer 6B is generated only in a desired thickness direction. Therefore, the grinding wheel 52 can be vibrated with sufficient amplitude in the desired thickness direction by the ultrasonic vibration generated by the ultrasonic vibrator 6B, and the difficult-to-cut material can be ground smoothly.

  In such a grinding operation, the grindstone mounting portion 522 of the grinding wheel 5A and the wheel mount 43 are coupled via a coupling portion 521 having an elastic coupling structure, and the grinding wheel mounting portion 522 is vibrated in the thickness direction. Since the lower side of the connecting portion 521 in which the through-hole 521 is formed follows and elastically displaces in the thickness direction, the ultrasonic vibration is not hindered. At the same time, since the upper side of the connecting portion 521 is fixed to the wheel mount 43 so as to be a restraining portion, the ultrasonic vibration is insulated so as not to be transmitted to the wheel mount 43 side.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, in the embodiment, the hole-shaped relief portions 513, 514, and 523 are formed as long and thin linear slit holes that are continuous in the vibration direction, but they can be absorbed so as to cancel the deflection based on the vibration in the direction other than the intended direction. As long as it has a shape, it may be a tapered slit hole that becomes wider from the inner peripheral side toward the outer peripheral side, or may be a structure in which a plurality of round through holes are arranged in the vibration direction. .

  Moreover, although the connection part 511 demonstrated in the example which has the three annular grooves 511b, for example, if it can follow the vibration of the grindstone mounting part 512 and can be elastically displaced in a radial direction, an inner peripheral surface or an outer periphery The surface may have at least one annular groove 511b.

  Further, since the annular groove 511b portion of the connecting portion 511 is elastic in the radial direction and the thickness direction, the connecting portion of the first embodiment is used instead of the connecting portion 521 in the second embodiment in which vibration is caused in the thickness direction. 511 may be used.

  Further, the connecting portion for connecting the wheel mount and the grindstone mounting portion is not limited to the configuration of the connecting portions 511 and 521. For example, in terms of materials, rubber, plastics (resin molded product), paper, oil In terms of structure, a spring shape, a damping structure (damper, hydraulic oil), or the like may be used as appropriate to have an elastic connection structure that does not hinder ultrasonic vibration.

It is a perspective view which shows the structural example of the whole grinding apparatus containing the grinding wheel of Embodiment 1 of this invention. It is a vertical side view of a spindle unit included in a grinding apparatus that also shows an electrical control system. It is a disassembled perspective view which shows a grinding wheel. It is sectional drawing of a part of connection part. 6 is a perspective view of a grinding wheel showing a modification of the first embodiment. FIG. It is a disassembled perspective view which shows the grinding wheel of Embodiment 2 of this invention.

Explanation of symbols

3 Grinding means 5, 5A Grinding wheel 6, 6A, 6B Ultrasonic vibrator 12 Chuck table 42 Rotating spindle 43 Wheel mount 51, 51A Wheel base 52 Grinding wheel 511, 521 Connecting portion 511b Circular groove 521b Through hole 512, 522 Whetstone mounting portion 513, 514, 523 Hole-shaped relief portion W Workpiece

Claims (7)

From a wheel base attached to a wheel mount provided at one end of a rotary spindle that constitutes a grinding means for grinding a workpiece held on a chuck table, and an annular grinding wheel mounted on the wheel base A grinding wheel that generates ultrasonic vibrations during grinding,
The wheel base is composed of an annular connecting portion connected to the wheel mount, and an annular grindstone mounting portion connected to the lower end portion of the connecting portion with the wheel mount side as an upper surface,
The grindstone mounting portion includes the grinding wheel mounted on the lower surface side and an ultrasonic vibrator that generates ultrasonic vibrations, and is in a direction orthogonal to the vibration direction of ultrasonic vibrations by the ultrasonic vibrators. Having a plurality of hole-like relief portions that are elongated in the vibration direction of the ultrasonic vibration penetrating the grindstone mounting portion, discretely in the circumferential direction,
The grinding wheel according to claim 1, wherein the coupling portion has an elastic coupling structure that does not hinder the vibration of the grindstone mounting portion by the ultrasonic vibrator. The ultrasonic transducer is mounted to generate ultrasonic vibration in a radial direction with respect to the grindstone mounting portion,
2. The grinding wheel according to claim 1, wherein the hole-shaped relief portion is formed so as to penetrate in a thickness direction of the grindstone mounting portion and to be elongated in a radial direction. The ultrasonic transducer is mounted to generate ultrasonic vibration in the thickness direction with respect to the grindstone mounting portion,
2. The grinding wheel according to claim 1, wherein the hole-shaped relief portion is formed to extend in a radial direction of the grindstone mounting portion and to be elongated in a thickness direction.   The connecting portion is characterized in that at least one annular groove is formed on an outer peripheral surface or an inner peripheral surface of the annular connecting portion, and has an elastic elastic connecting structure in a radial direction and a thickness direction. Item 4. The grinding wheel according to Item 2 or 3.   4. The connecting portion according to claim 3, wherein a plurality of through-holes penetrating in the radial direction of the annular connecting portion are elongated in the circumferential direction and have an elastic connecting structure that is elastic in the thickness direction. Grinding wheel as described in.   The grinding wheel according to any one of claims 1 to 5, wherein the hole-shaped relief portion is formed of a long and narrow slit hole in a vibration direction.   The grinding wheel according to any one of claims 1 to 6, wherein the hole-shaped relief portions are formed to be evenly dispersed in a circumferential direction of the grindstone mounting portion.

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