JP6202959B2 - Hydrostatic pad for double-sided surface grinding machine and double-sided surface grinding method for workpiece - Google Patents

Description

  The present invention relates to a static pressure pad for a double-sided surface grinding machine and a double-sided surface grinding method for a workpiece.

  In a horizontal double-sided surface grinder, when grinding both surfaces of a thin workpiece such as a silicon wafer using a pair of left and right grinding wheels, the hydrostatic fluid supplied to the hydrostatic support by the pair of left and right hydrostatic pads is used. The workpiece is rotated from both sides in the plate thickness direction with static pressure held, and the grinding fluid is supplied from the inner peripheral side of the pair of left and right grinding wheels to the grinding site, while both surfaces of the workpiece are predetermined by both grinding wheels. Grind to thickness.

  Conventionally, the static pressure pad used for double-sided surface grinding has a large static pressure support section so that the workpiece can be supported statically in almost the entire area of the static pressure pad main body, excluding the grinding stone placement area. Are arranged in the circumferential direction on the side closer to and far from the grindstone arrangement part, and the discharge passages with a narrow groove width are arranged in a mesh shape between the respective static pressure support parts (Patent Document 1), and the grindstone arrangement part A free region without a static pressure support portion is provided in the vicinity of the periphery, and a plurality of static pressure support portions and a mesh-like discharge passage are similarly disposed over substantially the entire area excluding the free region (Patent Document 2) There is.

JP 2005-205528 A JP 2007-529332 A

  In the conventional static pressure pad, in both the former and the latter cases, the area of each static pressure support portion is large and the circumference is long. A large amount of static pressure fluid is required, and the consumption of the static pressure fluid at the total static pressure support part is greatly increased. As the consumption of the static pressure fluid increases, the supply / recovery system of the static pressure fluid, etc. There is a problem that the incidental equipment becomes larger.

  In addition, the discharge passage between the static pressure support parts is a mesh with a narrow groove and the passage resistance is large, and a large amount of static pressure fluid from each static pressure support part is concentrated in the discharge passage to discharge the static pressure fluid. In addition to the time required, the grinding fluid supplied to the grinding part of the grinding wheel receives the centrifugal force of the grinding wheel and scatters toward the hydrostatic pad body. Tends to stay, which causes a problem that the grinding accuracy of the workpiece is lowered.

  For example, when the static pressure support part and the discharge passage approach the outer periphery of the grindstone placement part as in the former static pressure pad, the static pressure fluid from the static pressure support part and the grinding fluid scattered from the grinding stone are It may collide and stay in the vicinity of the inner periphery of the grindstone placement portion.

  In addition, when there is a free region near the outer periphery of the grindstone arrangement part as in the latter static pressure pad, the free region itself becomes a kind of staying pocket, and from the hydrostatic fluid from the static pressure support part and the grinding wheel A large amount of fluid may accumulate due to collision with the scattered grinding fluid in the free region.

  And if the fluid stays in the vicinity of the periphery of the grinding wheel arrangement part, especially the fluid containing a large amount of grinding fluid, the temperature of the grinding fluid rises due to the grinding heat during grinding of the workpiece by the grinding wheel, There is a possibility that the static pressure pad and the workpiece are locally thermally deformed due to the temperature rise of the grinding fluid and the grinding accuracy of the workpiece is lowered.

  In view of such problems, the present invention can reduce the consumption of static pressure fluid, reduce the size of ancillary equipment related to the supply / recovery of the static pressure fluid, and the like. It is another object of the present invention to provide a static pressure pad for a double-sided surface grinding machine and a double-sided surface grinding method for a workpiece, which can prevent a decrease in grinding accuracy due to retention of grinding fluid.

A static pressure pad for a double-sided surface grinding machine according to the present invention includes a plurality of static pressure support portions that statically support a workpiece via a static pressure fluid in a workpiece corresponding region excluding the grindstone arrangement portion of the static pressure pad main body, In a hydrostatic pad for a double-sided surface grinder comprising a hydrostatic fluid that has passed through the hydrostatic support portion, or a discharge passage that discharges the hydrostatic fluid and a grinding fluid that scatters from the grinding wheel arrangement portion side to the outside, Disperse the plurality of static pressure support portions in the work corresponding region via the discharge passage for discharging the static pressure fluid or the static pressure fluid and the grinding fluid scattered from the grindstone arrangement portion without staying , The total area of the static pressure support portion is made smaller than the total area of the discharge passage .

  You may arrange | position the said several static pressure support part in the circumferential direction through the said discharge path around the said grindstone arrangement | positioning part. The static pressure support portion includes a plurality of main static pressure support portions arranged in the circumferential direction around the grindstone arrangement portion via the discharge passage, and an outer peripheral portion of the workpiece corresponding region via the discharge passage. A plurality of auxiliary static pressure support portions may be included in the arranged circumferential direction.

As for each said static pressure support part, it is desirable for the outer periphery of the part near the said grindstone arrangement | positioning part to be a shape where a width | variety becomes small as it approaches the said grindstone arrangement | positioning part. The auxiliary static pressure support portion may have a projecting height smaller than that of the main static pressure support portion .

  Each of the static pressure support portions may have a pocket having a supply hole for a static pressure fluid and a land portion surrounding the pocket. The pocket may have a tapered surface that expands toward the workpiece, and the pocket may include a nozzle that discharges the static pressure fluid radially with respect to the tapered surface.

In the double-head surface grinding method for a workpiece according to the present invention, a workpiece is rotated in a state where the workpiece is statically supported from both sides via a static pressure fluid supplied to a static pressure support portion of the pair of static pressure pads, and a pair of grinding wheels A discharge passage for discharging a static pressure fluid or a static pressure fluid and a grinding fluid scattered from the grinding wheel without staying when grinding both surfaces of the workpiece with the grinding stone while supplying a grinding fluid from a grinding portion to a grinding portion A plurality of the static pressure support portions are arranged in a work corresponding region, and the total area of the static pressure support portions is smaller than the total area of the discharge passage. .

  According to the present invention, the consumption of static pressure fluid can be reduced, and ancillary equipment related to supply / recovery of the static pressure fluid can be reduced in size, and the retention of the static pressure fluid or the static pressure fluid and the grinding fluid can be reduced. There is an advantage that the accompanying reduction in grinding accuracy can be prevented.

1 is a schematic side view of a horizontal double-sided surface grinding machine showing a first embodiment of the present invention. It is the same front sectional drawing. It is an expanded sectional view of the static pressure pad. It is an enlarged view of the static pressure support part of the static pressure pad. It is scattering explanatory drawing of the grinding fluid. It is scattering explanatory drawing of the grinding fluid. It is sectional drawing of the static pressure pad which shows the 2nd Embodiment of this invention. It is sectional drawing of the static pressure pad which shows the 3rd Embodiment of this invention. It is a side view of the static pressure pad which shows the 4th Embodiment of this invention. It is a side view of the static pressure pad which shows the modification. It is a side view of the static pressure pad which shows the 5th Embodiment of this invention. It is a side view of the static pressure pad which shows the 6th Embodiment of this invention. It is a side view of the static pressure pad which shows the 7th Embodiment of this invention. It is a side view of the static pressure pad which shows the 8th Embodiment of this invention. It is a side view of the static pressure pad which shows the 9th Embodiment of this invention.

  Hereinafter, an embodiment of the present invention employed in a horizontal double-sided surface grinding machine that performs surface grinding on both surfaces of a thin plate-like workpiece such as a silicon wafer will be exemplified. 1 is a schematic side view of a horizontal double-sided surface grinding machine, FIG. 2 is a schematic front sectional view thereof, FIG. 3 is an enlarged sectional view of a static pressure pad, and FIG. 4 is an enlarged view of a static pressure support portion of the static pressure pad. The protruding amount of the static pressure support portion, the thickness of the workpiece, etc. are exaggerated for easy understanding.

  As shown in FIGS. 1 and 2, the horizontal double-sided surface grinding machine is disposed so as to face each other on the left and right sides, and a pair of left and right hydrostatic pads 1 that support the work W via a hydrostatic fluid such as hydrostatic pressure. And a pair of left and right sides that grind both the left and right sides of the workpiece W that is rotatably arranged around the axis in the left and right direction and supported by the static pressure pad 1 corresponding to the grindstone arrangement portion 2 of each static pressure pad 1. And a carrier 4 for rotating the workpiece W supported by the static pressure pad 1 around the substantially central axis thereof.

  The grinding wheel 3 is a cup-type grinding wheel or the like. When grinding the workpiece W, a grinding fluid such as grinding water is supplied from the inner peripheral side to the grinding part 5 as indicated by an arrow in FIG. . The outer periphery of the carrier 4 is held by a carrier ring 6, and the carrier ring 6 is rotatably supported by a plurality of support means 7 in the circumferential direction. The carrier ring 6 has a ring gear 8 on its inner periphery, and is driven to rotate about the axis in the left-right direction by a drive gear 9 that meshes with the upper side of the ring gear 8.

  As the support means 7, an appropriate means such as a roller type, a belt type or a static pressure support type may be adopted. In general, three or more support means 7 are arranged in the circumferential direction in the case of a roller type or a static pressure support type, and two or more in the circumferential direction in the case of a belt type. Is not a problem.

  Each static pressure pad 1 has a workpiece-corresponding region 12 corresponding to the workpiece W and is formed in a substantially disc-shaped static pressure pad body 10 larger than the workpiece W, and a workpiece-corresponding region 12 of the static pressure pad body 10. Static pressure support portions 13-1 to 13-3, 14-1 to 14-4 that are arranged in a dispersed manner and support the workpiece W via a static pressure fluid, and static pressure support portions 13-1 to 13-. 3 and 14-1 to 14-4, and a discharge passage 17 for discharging the static pressure fluid and the grinding fluid without retaining them.

  The hydrostatic pad main body 10 has a notch formed on the lower side of the work corresponding area 12 in the thickness direction, and a step corresponding to the carrier ring 6 or the like on the entire outer periphery of the work corresponding area 12. Part 11 is formed. A grinding wheel 3 for grinding the workpiece W is disposed in the grinding wheel placement portion 2.

  The static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 are distributed and arranged via the discharge passage 17 in the work corresponding region 12 excluding the grindstone arrangement portion 2 of the static pressure pad main body 10. Yes. Each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 includes a pocket 15 provided with a static pressure fluid supply hole 23 in the approximate center, and a work W side surrounding the pocket 15. And an annular land portion 16 projecting toward the center. A wide discharge passage 17 is continuously formed between each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. Support portions 13-1 to 13-3 and 14-1 to 14-4 are dispersed in the work corresponding area 12.

  As shown in FIG. 1 and FIG. 2, the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 are near the periphery of the grinding wheel 3 (near the periphery of the grindstone placement portion 2). Corresponding to a plurality of (for example, three) main static pressure support portions 13-1 to 13-3 arranged at predetermined intervals in the circumferential direction and the outer peripheral portion of the workpiece corresponding region 12 (the outer peripheral portion of the workpiece W). There are two types of auxiliary static pressure support parts 14-1 to 14-4 (for example, four) arranged at predetermined intervals in the circumferential direction.

  Among the three main static pressure support portions 13-1 to 13-3, the intermediate main static pressure support portion 13-1 is disposed in the vicinity of the upper side of the grinding wheel 3, and the main static pressure support portions 13-2 on both sides are arranged. 13-3 is arrange | positioned at the both sides of the radial direction of the grindstone arrangement | positioning part 2 and the grinding grindstone 3, respectively. The main static pressure support portions 13-1 to 13-3 have an outer peripheral land portion 16 having a substantially perfect circle shape, and a pocket 15 is provided substantially concentrically on the inner side.

  As shown in FIGS. 3 and 4, the pocket 15 of the main static pressure support portions 13-1 to 13-3 has a tapered surface 18 that expands from the bottom surface side to the opening side (work W side) on the inner periphery. A shallow large-diameter portion 20 is provided on the opening end side, and a supply nozzle 22 for supplying a static pressure fluid radially toward the tapered surface 18 is provided at the approximate center on the bottom surface side.

  The supply nozzle 22 has a nozzle head 25 that is screwed to the supply hole 23 side of the hydrostatic pad main body 10 via a screwing portion 24, and a plurality of nozzle holes 26 are radially formed in the nozzle head 25 in the circumferential direction. Has been.

  Of the four auxiliary static pressure support portions 14-1 to 14-4, the two intermediate auxiliary static pressure support portions 14-1 and 14-2 are driven above the intermediate main static pressure support portion 13-1. The auxiliary static pressure support portions 14-3 and 14-4 on both sides in the circumferential direction are arranged on both sides in the circumferential direction sandwiching the gear 9, and the static pressure pad main body 10 is located with respect to the intermediate main static pressure support portion 13-1. The main static pressure support portions 13-2 and 13-3 are arranged on both sides in the radial direction and on the diagonally outer upper sides of both ends in the circumferential direction.

  Further, the four auxiliary static pressure support portions 14-1 to 14-4 have a slightly lower protrusion amount toward the workpiece W than the main static pressure support portions 13-1 to 13-3. This is because when the workpiece W is warped, the static pressure of the hydrostatic fluid strongly acts on the outer peripheral portion of the workpiece W so as not to hinder the grinding accuracy of the workpiece W.

  The main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 are connected to different supply sources (not shown) because of the difference in height. The workpiece W is supported by substantially the same static pressure by the supplied hydrostatic fluid. Each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 may be connected to a common supply source through adjusting means such as a flow rate adjusting valve and a pressure adjusting valve.

  Although the static pressure fluids of the main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 of the left and right static pressure pads 1 are substantially equal, From the viewpoint of easily absorbing the warpage of W, the static pressure on the auxiliary static pressure support portions 14-1 to 14-4 side may be slightly lower than the main static pressure support portions 13-1 to 13-3 side. .

  The height difference between the auxiliary static pressure support portions 14-1 to 14-4 and the main static pressure support portions 13-1 to 13-3 is suitably about 2 to 30 μm, for example. What is necessary is just to determine suitably in the range which can ease the influence on the grinding precision of the workpiece | work W in consideration of conditions. The main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 may have substantially the same height.

  As shown in FIG. 3, the pockets 15 of the auxiliary static pressure support portions 14-1 to 14-4 are from the bottom surface side to the opening side (work W side) in the same manner as the main static pressure support portions 13-1 to 13-3. A tapered surface 19 that expands is provided on the inner periphery.

  The four auxiliary static pressure support portions 14-1 to 14-4 are land portions at the center side portion (grinding stone placement portion 2 side) and the outer peripheral side portion (opposite side of the grinding stone placement portion 2 side) of the workpiece corresponding region 12. The outer peripheral shape of 16 differs. For example, the central portion of the land portion 16 has a predetermined width and is substantially concentric with the pocket 15, while the outer peripheral portion of the land portion 16 extends along the outer peripheral edge of the workpiece corresponding region 12. It is long in the circumferential direction. This is because a part of the land portion 16 is used to provide a work suction hole (not shown) used when the work W is loaded.

In addition, you may comprise the outer periphery shape of auxiliary | assistant static pressure support parts 14-1 to 14-4, ie, the outer periphery shape of the land part 16, in circular shape similarly to the main static pressure support parts 13-1 to 13-3. It is also possible to select a curved shape or a bent shape other than a circular shape according to the conditions of the peripheral portion of the arrangement site. However, from the viewpoint of discharging the static pressure fluid and grinding fluid in the discharge passage 17 without retaining them, the main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 are , the outer periphery of a portion close to the grindstone arranging section 2, it is desirable width closer to the grindstone arrangement portion 2 has a shape such that small.

  In the workpiece corresponding region 12 of the static pressure pad main body 10, a discharge passage 17 is continuously formed outside the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. The discharge passage 17 has a discharge capacity necessary for quickly discharging the static pressure fluid and the grinding fluid in the discharge passage 17 to the outside of the static pressure pad 1 without retaining the static pressure fluid and the grinding fluid. The discharge capacity per unit time is larger than the flow rate of fluid and grinding fluid per unit time.

  For example, the discharge passage 17 is ground to the supply amount per unit time of the static pressure fluid whose discharge capacity per unit time is supplied to the static pressure support portions 13-1 to 13-3, 14-1 to 14-4. The discharge passage 17 has a passage cross-sectional area that is substantially the same as or larger than the total sum of the inflows per unit time of the grinding fluid flowing into the discharge passage 17 from the grindstone 3 through the grinding part 5. The internal static pressure fluid and the grinding fluid are configured to be discharged quickly without generating a positive static pressure.

  Accordingly, the workpiece-corresponding region 12 excluding the grindstone placement portion 2 of the static pressure pad main body 10 has a sufficient passage cross-sectional area that can quickly discharge the static pressure fluid and the grinding fluid without generating a positive static pressure. There is a passage 17, and a plurality of static pressure support portions 13-1 to 13-3, 14-1 to 14-4 are arranged in a distributed manner via the discharge passage 17, and the individual static pressure support portions 13 are arranged. -1 to 13-3 and 14-1 to 14-4 have a relatively small area.

  The intermediate two auxiliary static pressure support portions 14-1 and 14-2 are arranged on the upper side opposite to the grinding wheel 3 with respect to the intermediate main static pressure support portion 13-1, and the auxiliary static pressure support portions at both ends. 14-3 and 14-4 are arrange | positioned on the diagonal outer side substantially opposite to the grinding stone 3 with respect to the main static pressure support parts 13-2 and 13-3 of both sides.

  Therefore, when viewed from the grindstone placement portion 2 side, the four auxiliary static pressure support portions 14-1 to 14-4 are positioned behind the three main static pressure support portions 13-1 to 13-3. It is in. And by the intermediate | middle main static pressure support part 13-1 and the intermediate | middle auxiliary | assistant static pressure support parts 14-1 and 14-2, the vertical direction (longitudinal direction) which passes along the approximate center of the static pressure pad 1 and the grinding stone 3 is demonstrated. The first static pressure support part row 29 is also supported by the first static pressure support parts 13-2 and 13-3 on both ends and the auxiliary static pressure support parts 14-3 and 14-4 on both ends. A second static pressure support portion row 30 in an oblique direction is formed on both sides of the portion row 29, and the grindstone placement portion 2 is disposed between the first static pressure support portion row 29 and the second static pressure support portion row 30. A main passage portion 17a having a wide passage width is provided substantially linearly or radially from the substantially center of the grinding wheel 3 to the outside.

  When both surfaces of the workpiece W are surface ground, the workpiece W in the carrier 4 is statically supported by a pair of left and right static pressure pads 1 via a hydrostatic fluid, and the workpiece W is driven via the carrier 4 by driving of the drive gear 9. The workpiece W is ground by the rotation of the pair of grinding wheels 3 while rotating around the axis. At this time, the grinding fluid is supplied from the inner peripheral side to the grinding portion 5 of each grinding wheel 3.

  When a static pressure fluid is supplied to each pocket 15 of the static pressure pad 1, the static pressure fluid is between the land portion 16 of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 and the workpiece W. Therefore, the work W can be supported by static pressure through the static pressure fluid.

  The hydrostatic fluid that has passed through the hydrostatic support portions 13-1 to 13-3 and 14-1 to 14-4, and the grinding fluid that has flowed in from the grinding wheel 3 side do not stay through the discharge passage 17. It can be quickly discharged to the outside of the static pressure pad main body 10. For this reason, the problem accompanying the retention of the static pressure fluid and the grinding fluid in the discharge passage 17 can be solved, and the grinding accuracy of the workpiece can be improved.

  Further, the hydrostatic fluid from the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 is scattered from the grinding wheel 3 side to the workpiece corresponding region 12 excluding the grindstone placement portion 2 of the static pressure pad main body 10. Thus, a discharge passage 17 necessary for discharging the flowing grinding fluid without staying is secured, and a plurality of static pressure support portions 13-1 to 13-3, 14-1 are provided via the discharge passage 17. 14-4 are arranged in a dispersed manner, so that each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 is compared with a case where the discharge passage 17 is a mesh having a narrow groove width. The ratio to the whole becomes small, and the area of each static pressure support part 13-1 to 13-3, 14-1 to 14-4 can be made small.

  Thus, the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 can be reduced by reducing the area of each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. Even when the workpiece W is statically supported via the supplied static pressure fluid, it is possible to reliably support the workpiece W while suppressing the supply amount of the static pressure fluid to be small. Therefore, the supply amount of the static pressure fluid necessary for static pressure support of the workpiece W by all the static pressure support portions 13-1 to 13-3, 14-1 to 14-4 is reduced, and the consumption amount of the static pressure fluid is reduced. Can be significantly reduced, and incidental equipment required for supplying and collecting the hydrostatic fluid can be reduced in size.

  Further, if the area of each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 is reduced, the workpiece W can be statically supported over substantially the entire work corresponding region 12 excluding the grindstone placement portion 2. However, since the workpiece W rotating at high speed while being held by the carrier 4 is dispersedly supported by the plurality of static pressure support portions 13-1 to 13-3 and 14-1 to 14-4, the pair of grinding wheels 3 are used. Combined with grinding by sandwiching the workpiece W from both sides, it is possible to stably support the workpiece W with static pressure without generating vibration in the thickness direction.

  In addition, the area of each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 is reduced, and the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 are reduced. If the supply amount of the static pressure fluid is reduced, the supply of the static pressure fluid becomes possible only by providing one supply hole 23 in the approximate center of the pocket 15, so that the static pressure provided inside and outside the static pressure pad main body 10 is achieved. There is an advantage that a communication path for fluid supply can be simplified.

  Further, the workpiece W is supported in the vicinity of the grinding wheel 3 by the hydrostatic fluid of the three inner main static pressure support portions 13-1 to 13-3, and protrudes from the main static pressure support portions 13-1 to 13-3. Since the outer peripheral portion of the workpiece W is supplementarily supported by the static pressure fluid of the four auxiliary static pressure support portions 14-1 to 14-4 having a small amount, even if the workpiece W has a slight warp, It is possible to perform grinding while reliably supporting the workpiece W with static pressure without being affected by warpage, and the grinding accuracy can be improved.

  Since the pockets 15 of the three main static pressure support portions 13-1 to 13-3 have a two-stage structure having a shallow large-diameter portion 20 on the opening side, the two-stage structure has the same diameter as the opening end of the large-diameter portion 20. Compared with the case not having the above, the opening amount can be increased while reducing the capacity in the pocket 15. For this reason, the support range when the workpiece W is statically supported via the static pressure fluid can be increased, and the amount of the static pressure fluid required for static pressure support of the workpiece W can be reduced.

  The pockets 15 of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 have tapered inner surfaces 18 and 19, and are supplied from the supply nozzle 22 on the center side. Since the static pressure fluid flows while diffusing along the tapered surfaces 18 and 19 of the pocket 15, vortices are not generated in the static pressure fluid in each pocket 15, and the land portion 16 is substantially evenly distributed around the entire circumference. The hydrostatic fluid can be diffused.

  The main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 may be supplied with the same amount of static pressure fluid, but the main static pressure support portions 13-1 to 13-13 may be the same. -3 has a supply nozzle 22 in the pocket 15 and a taper surface 18 on the inner periphery of the land portion 16, so that the supply amount of the static pressure fluid in the main static pressure support portions 13-1 to 13-3 is reduced to the auxiliary static pressure. It is possible to make it larger than the pressure support portions 14-1 to 14-4 side.

  This is because the static pressure fluid is supplied radially from the plurality of nozzle holes 26 in the circumferential direction of the supply nozzle 22 to the pockets 15 of the main static pressure support portions 13-1 to 13-3. Then, after the static pressure fluid flows along the tapered surface 18 toward the opening side of the pocket 15, the static pressure fluid passes through the large-diameter portion 20 and the land portion 16 of the main static pressure support portions 13-1 to 13-3 and the workpiece W. Flows almost uniformly from the entire circumference of the gap to the outside.

  Therefore, even if the supply amount of the static pressure fluid of the main static pressure support portions 13-1 to 13-3 is larger than that of the auxiliary static pressure support portions 14-1 to 14-4, supply of the static pressure fluid is started. Sometimes, the static pressure fluid does not hit the workpiece W at a substantially right angle and cause a shock locally.

  Further, during grinding of the workpiece W, a grinding fluid is supplied from the inner peripheral side of the grinding wheel 3 to the grinding portion 5, and the grinding fluid receives the centrifugal force of the grinding wheel 3 and is applied to the grinding wheel placement portion 2 of the hydrostatic pad 1. As shown in FIG. 5 and FIG. 6, the part scatters toward the inner peripheral side, hits the main static pressure support portions 13-1 to 13-3 in the vicinity of the grinding wheel 3, or each main static pressure support. The fluid flows between the parts 13-1 to 13-3 and flows into the workpiece corresponding region 12 side of the static pressure pad main body 10.

  However, the outer peripheral shape of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 on the side of the grindstone arrangement portion 2 is difficult to prevent the flow of the grinding fluid, and each main static pressure support. The auxiliary static pressure support portions 14-1 to 14-4 are respectively located behind the portions 13-1 to 13-3, and the intermediate main static pressure support portion 13-1 and the auxiliary static pressure support portion 14-1, The first static pressure support part row 29 constituted by 14-2, the main static pressure support parts 13-2, 13-3 and the auxiliary static pressure support parts 14-3, 14-4 on both ends. 2 Since there is a main passage portion 17a having a wide passage width extending substantially linearly in the radial direction from the approximate center of the grinding wheel 3 between the static pressure support portion row 30, the grinding fluid flowing into the workpiece corresponding region 12 side is It can be quickly discharged out of the static pressure pad body 10 through the discharge passage 17 together with the static pressure fluid.

  Further, since the static pressure fluid and the grinding fluid in the discharge passage 17 can be smoothly discharged, the gap between the grindstone disposition portion 2 of the static pressure pad 1 and the grinding grindstone 3 is reduced to reduce the main static pressure support portions 13-1 to 13-13. -3 can be arranged as close as possible to the vicinity of the periphery of the grinding wheel 3. For this reason, the work W is surely statically fixed on the main static pressure support portions 13-1 to 13-3 side even though the width of the discharge passage 17 between the main static pressure support portions 13-1 to 13-3 is large. It is possible to improve the grinding accuracy by supporting with pressure.

  FIG. 7 illustrates a second embodiment of the present invention. In this embodiment, in addition to the pockets 15 of the main static pressure support portions 13-1 to 13-3 of the static pressure pad 1, the pockets 15 of the auxiliary static pressure support portions 14-1 to 14-4 are also circumferentially arranged. A supply nozzle 32 having nozzle holes 31 radially is provided on the bottom surface side. Further, a shallow large-diameter portion 21 is provided on the opening end side of the pocket 15 of the auxiliary static pressure support portions 14-1 to 14-4 similarly to the pocket 15 of the main static pressure support portions 13-1 to 13-3. Yes.

  In this manner, the supply nozzles 22 and 32 and the large diameter portions 20 and 21 may be provided in the pockets 15 of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. The pockets 15 of the auxiliary static pressure support portions 14-1 to 14-4 may omit either the supply nozzle 32 or the large diameter portion 21.

  FIG. 8 illustrates a third embodiment of the present invention. In this embodiment, the pockets 15 of the main static pressure support portions 13-1 to 13-3 and the pockets 15 of the auxiliary static pressure support portions 14-1 to 14-4 of the static pressure pad 1 are all directly cylindrical. The supply nozzles 22 and 32 and the tapered surfaces 18 and 19 of the first and second embodiments are omitted.

  As described above, the pocket 15 of each of the static pressure support portions 13-1 to 13-3, 14-1 to 14-4 has a cylindrical shape on the inner peripheral surface, and does not include the supply nozzles 22 and 32 and the tapered surfaces 18 and 19. But you can. The large diameter portions 20 and 21 may be omitted.

  FIG. 9 illustrates a fourth embodiment of the present invention, and FIG. 10 illustrates a modification thereof. In this embodiment, a plurality of, for example, four main static pressure support portions 13-1 to 13-4 in FIG. 9 and five main static pressure support portions 13-1 in FIG. To 13-5 are arranged, respectively, and the auxiliary static pressure support portions 14-1 to 14-4 on the outer peripheral side in the first to third embodiments are omitted.

  In FIG. 9, main static pressure support portions 13-3 and 13-4 on both ends in the circumferential direction are arranged in the vicinity of both sides in the radial direction of the grinding wheel 3, and the remaining two main static pressure support portions 13-1 and 13-2 are arranged. 13-2 are arranged at substantially equal intervals in the middle in the circumferential direction.

  In FIG. 10, main static pressure support portions 13-1, 13-4, and 13-5 are arranged close to the grinding wheel 3 at three locations in the circumferential direction and at both ends, and the remaining two main static pressures are arranged. The pressure support portions 13-2 and 13-3 are arranged at a distance from the grinding wheel 3 in the middle in the circumferential direction.

  As described above, the workpiece W may be statically supported only by the main static pressure support portions 13-1 to 13-4 or the main static pressure support portions 13-1 to 13-5. In addition, when the number increases so that five main static pressure support parts 13-1 to 13-5 are provided in the circumferential direction, some of the main static pressure support parts 13-2 and 13-3 are The passage width of the discharge passage 17 between the main static pressure support portions 13-1 to 13-5 may be secured slightly away from the grinding wheel 3.

  FIG. 11 illustrates a fifth embodiment of the present invention. In this embodiment, a recess 34 is provided between the main static pressure support portions 13-1 to 13-3 of the static pressure pad main body 10 so as to be continuous with the grindstone placement portion 2. The gap between the inner periphery of the main body 10 and the grinding wheel 3 is large.

  When the plurality of main static pressure support portions 13-1 to 13-3 are arranged around the grinding wheel 3, the recesses 34 are provided between the main static pressure support portions 13-1 to 13-3 as described above. The grinding fluid may be discharged to the back side of the hydrostatic pad main body 10.

  FIG. 12 illustrates a sixth embodiment of the present invention. In this embodiment, a plurality of static pressure support portions 13-1 to 13-13 are provided in the vicinity of the periphery of the grindstone arrangement portion 2 with a predetermined space between the inner periphery of the static pressure pad main body 10 on the grindstone arrangement portion 2 side. -3 is arranged.

  For example, among the three static pressure support portions 13-1 to 13-3, the two static pressure support portions 13-2 and 13-3 are the central portion of the grinding wheel 3 disposed in the grindstone placement portion 2. It arrange | positions on the both sides of the circumferential direction with respect to the grindstone arrangement | positioning part 2 on the substantially concentric circle 33a of the workpiece | work W which passes an outer side rather than O1. In addition, one static pressure support portion 13-1 is disposed in the vicinity of the center portion O2 of the workpiece W and at the approximate center between the static pressure support portions 13-2 and 13-3.

  The static pressure support portions 13-2 and 13-3 do not need to be on the concentric circle 33a of the workpiece W, and are sufficient if they are in the vicinity of the workpiece W in the radial direction. Other configurations are the same as those of each embodiment.

  Thus, also when disposing and disposing the plurality of static pressure support portions 13-1 to 13-3 near the periphery of the grindstone placement portion 2, the grinding wheel 3 and the respective static pressure support portions 13-1 to 13-3 are disposed. If a predetermined interval is secured between the pair of left and right grinding wheels 3 and the pair of left and right static pressure pads 1, even if there is a difference in the horizontal direction, the workpiece W is tracked along the difference. It is possible to prevent the grinding accuracy from being lowered.

  Moreover, by disposing the static pressure support portions 13-2 and 13-3 on both sides in the circumferential direction with respect to the grindstone placement portion 2 on the substantially concentric circle 33a of the work W passing outside the center portion O1 of the grinding grindstone 3, The workpiece W can be reliably statically supported at substantially constant positions on both sides of the grinding wheel 3. Moreover, the center side of the workpiece | work W can be supported by the static pressure support part 13-1.

  FIG. 13 illustrates a seventh embodiment of the present invention. In this embodiment, a plurality of static pressure support portions 13-1 to 13-4 are arranged in the circumferential direction corresponding to the vicinity of the outer periphery of the workpiece W (work corresponding region 12). For example, among the four main static pressure support portions 13-1 to 13-4, intermediate main static pressure support portions 13-1 and 13-2 are arranged on both sides of the drive gear 9 above the grinding wheel 3, The main static pressure support portions 13-3 and 13-4 on both sides are arranged on substantially both sides in the radial direction of the grindstone arrangement portion 2 and the grinding wheel 3, respectively.

  The main static pressure support portions 13-1 to 13-4 have substantially the same size, and the outer peripheral land portion 16 has a substantially perfect circle shape, and the pocket 15 is provided substantially concentrically on the inner side. . However, the size, shape, and structure may be changed, for example, the main static pressure support portions 13-3 and 13-4 on both sides may be slightly larger than the intermediate main static pressure support portions 13-1 and 13-2.

  Depending on conditions such as the thickness and diameter of the workpiece W, a plurality of static pressure support portions 13-1 to 13-4 are arranged in the circumferential direction on the static pressure pad main body 10 corresponding to the vicinity of the outer periphery of the workpiece W in this way. Thus, it is possible to support the vicinity of the outer periphery of the workpiece W with a hydrostatic fluid.

  FIG. 14 illustrates an eighth embodiment of the present invention. In this embodiment, three main static pressure support portions 13-1 to 13-3 are arranged in the circumferential direction in proximity to the grinding wheel 3, and the circumferential direction of the main static pressure support portions 13-1 to 13-3 is arranged. Two auxiliary static pressure support portions 14-1 and 14-2 are arranged at positions in the middle of the grinding wheel 3 and away from the grinding wheel 3.

  Thus, besides the plurality of main static pressure support portions 13-1 to 13-3, the plurality of auxiliary static pressure support portions 14- closer to the outer periphery of the workpiece W than the main static pressure support portions 13-1 to 13-3. In the case of dispersively arranging 1 and 14-2, the auxiliary static pressure support portions 14-1 and 14-2 can be arranged on the inner side of the outer periphery of the work corresponding region 12.

  FIG. 15 illustrates a ninth embodiment of the present invention. In this embodiment, the land portions 16 of the auxiliary static pressure support portions 14-1 and 14-2 are configured to be elongated in one direction in an oval shape or an elliptical shape.

In providing the auxiliary static pressure support portions 14-1 and 14-2, the land portion 16 can be formed into an oval shape, an oval shape, or other shapes as described above. In this case, the discharge passage 17 is provided. so as not to inhibit the flow of static fluid, the land portion 16, the outer periphery of a portion close to the grindstone arranging section 2, it is desirable width closer to the grindstone arrangement portion 2 has a shape such that small.

  The land portions 16 of the auxiliary static pressure support portions 14-1 and 14-2 may be elongated in the rotation direction of the workpiece W, or may be elongated in the perspective direction passing through the approximate center of the grinding wheel 3 or the vicinity thereof. . Moreover, you may lengthen in the direction which cross | intersects diagonally with respect to the perspective direction which passes through the approximate center of the grinding stone 3, or its vicinity. Therefore, as the outer peripheral shape of the land portion 16 of the auxiliary static pressure support portions 14-1 and 14-2, any shape can be adopted as long as it does not impair the flow of the static pressure fluid in the discharge passage 17. .

  Note that the land portions 16 of the main static pressure support portions 13-1 to 13-3 may also be configured to be long in a specific direction, similar to the auxiliary static pressure support portions 14-1 and 14-2.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited to this embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, the numbers of the main static pressure support portions 13-1 to 13-3 and the auxiliary static pressure support portions 14-1 to 14-4 can be appropriately changed in consideration of the diameter of the workpiece W, for example. It is possible to have five main static pressure support parts and six auxiliary static pressure support parts. However, it is desirable that the number of main static pressure support portions be three or more.

  Further, the side view shape of the pocket 15 of each of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 is preferably a perfect circle from the viewpoint of processing, but in a perspective direction with respect to the grinding wheel 3. A shape other than a perfect circle, such as a long ellipse or a bent shape such as an S-shape, may be used. As the cross-sectional shape of the pocket 15, a shape such as a two-stage shape, a tapered shape, and a right cylindrical shape can be appropriately employed.

  It is desirable to provide a wide discharge passage 17 in the direction passing through the approximate center of the grinding wheel 3 or in the direction close to it while avoiding interference with other attachment means on the workpiece corresponding region 12 side of the static pressure pad 1. . In providing the discharge passage 17, the auxiliary static pressure support portions 14-1 to 14-4 may be omitted, or the main static pressure support portions 13-1 to 13-3 are brought close to the main static pressure support portions. It is also possible to dispose the same number of auxiliary static pressure support portions as the number of main static pressure support portions or a number smaller than that of the main static pressure support portion behind the grinding wheel 3 with respect to the main static pressure support portion.

  The gap between the grindstone placement portion 2 of the hydrostatic pad 1 and the grinding grindstone 3 may be increased or decreased. However, if the gap is too large, the grinding accuracy will be affected by the warp of the workpiece W. Therefore, it is necessary to make the gap so as not to affect the grinding accuracy.

  The passage sectional area (discharge capacity) of the discharge passage 17 is determined by the relative relationship between the supply amount of the static pressure fluid and the inflow amount of the grinding fluid, and the supply amount (consumption amount) of the static pressure fluid is determined by the static pressure support portion. It depends on the area and the number of static pressure supports. For example, the area (size) of the static pressure support part is appropriate to the degree exemplified in each embodiment, but the area of the static pressure support part is made smaller than in each embodiment, and the number of static pressure support parts is It is also possible to increase.

  When ensuring the discharge capacity of the discharge passage 17, the total area of the discharge passage 17 may be made larger than the total area of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. If the passage depth is large, the total area of the discharge passage 17 may be made smaller than the total area of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4. Therefore, when the number of the static pressure support portions 13-1 to 13-3 and 14-1 to 14-4 increases and the width of the discharge passage 17 between them becomes narrow, each of the static pressure support portions 13-1 to 13-1. The height of 13-3, 14-1 to 14-4 may be increased to ensure the discharge capacity of the discharge passage 17.

  The bottom surface side of the discharge passage 17 of the static pressure pad main body 10 is flat and the entire depth of the discharge passage 17 is the same, but the depth of the main passage portion 17a is increased, etc. The depth may be partially different as long as the discharge performance is improved.

  In each embodiment, the case where the grinding fluid flows into the discharge passage 17 from the grinding wheel 3 side is illustrated, but there is no inflow of the grinding fluid from the grinding wheel 3 side or the inflow amount of the grinding fluid is almost the same. When it does not cause a problem, the discharge capacity of the discharge passage 17 may be determined in consideration of the static pressure fluid.

DESCRIPTION OF SYMBOLS 1 Static pressure pad 2 Grinding wheel arrangement | positioning part 3 Grinding wheel 4 Carrier 5 Grinding part 10 Static pressure pad main body 12 Work area | region 13-1 to 13-3 Main static pressure support part 14-1 to 14-4 Auxiliary static pressure support part 15 Pocket 16 Land portion 17 Discharge passage 17a Main passage portions 18, 19 Tapered surfaces 22, 32 Supply nozzle 29 First static pressure support portion row 30 Second static pressure support portion row W Workpiece

Claims (8)

A plurality of static pressure support portions that statically support a workpiece via a static pressure fluid and a static pressure fluid that passes through the static pressure support portion or a static pressure in a workpiece corresponding region excluding a grinding stone arrangement portion of the static pressure pad main body. In a static pressure pad for a double-sided surface grinder provided with a fluid and a discharge passage for discharging grinding fluid scattered from the grinding wheel arrangement portion side to the outside,
Disperse the plurality of static pressure support portions in the work corresponding region via the discharge passage for discharging the static pressure fluid or the static pressure fluid and the grinding fluid scattered from the grindstone arrangement portion without staying ,
A static pressure pad for a double-head surface grinding machine, wherein the total area of the static pressure support portion is smaller than the total area of the discharge passage . The hydrostatic pad for a double-head surface grinder according to claim 1, wherein a plurality of the hydrostatic support portions are arranged in the circumferential direction around the grindstone arrangement portion via the discharge passage. The static pressure support part includes a plurality of main static pressure support parts arranged in the circumferential direction around the grindstone arrangement part via the discharge passage;
3. The double-sided surface grinding machine according to claim 1, further comprising a plurality of auxiliary static pressure support portions arranged in a circumferential direction on the outer peripheral portion of the workpiece corresponding region via the discharge passage. Static pressure pad. The double-head surface grinder according to any one of claims 1 to 3, wherein each of the static pressure support portions has a shape in which an outer periphery of a portion close to the grindstone placement portion becomes smaller in width as the grindstone placement portion is approached. Static pressure pad for use. The hydrostatic pad for a double-head surface grinding machine according to claim 3, wherein the auxiliary static pressure support portion has a projection height smaller than that of the main static pressure support portion. Each static pressure support part has a pocket which has a supply hole of a static pressure fluid, and a land part which surrounds the pocket. The static for a double-head surface grinder according to any one of claims 1 to 5 characterized by things. Pressure pad. The pocket has a tapered surface that expands toward the workpiece;
The static pressure pad for a double-sided surface grinder according to claim 6 , wherein nozzles for discharging the static pressure fluid radially with respect to the tapered surface are provided in the pocket. While rotating the workpiece in a state of static pressure support from both sides via the static pressure fluid supplied to the static pressure support portion of the pair of static pressure pads, while supplying the grinding fluid from the pair of grinding wheels to the grinding site, When grinding both surfaces of the workpiece with the grinding wheel,
A plurality of the static pressure support portions are distributed and arranged in the work corresponding area via a discharge passage for discharging the static pressure fluid or the static pressure fluid and the grinding fluid scattered from the grinding wheel without staying, and the static pressure support A method of double-side surface grinding of a workpiece, wherein the static pressure pad is used in which the total area of the portion is smaller than the total area of the discharge passage .

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