JP2010253658A - Non-contact workpiece holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small type non-contact workpiece holding device having stable and high holding force with little energy. <P>SOLUTION: A connecting part 12A, a spiral passage forming part 12B, a diameter reducing part 12C, a turning flow forming part 12D and an opening part 12E are formed from an upper side in a housing 11 having a rotation symmetrical inner peripheral surface. A block member 13 provided with a spiral projecting line 14 on an outer peripheral surface is inserted into the spiral passage forming part 12B. A spiral passage is formed by contact of the spiral projecting line 14 and the spiral passage forming part 12B. High pressure gas is jetted to the diameter reducing part 12C through a spiral flow passage and a turning flow is formed in the turning flow forming part 12D. The formed turning flow is made to flow out of the opening part 12E. A workpiece W is arranged to face to the opening part 12E and the workpiece W is held by imparting floating force to the workpiece W by negative pressure at a center of the turning flow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a non-contact holding device for holding an object in a non-contact manner through a fluid.

  A Bernoulli chuck that holds a workpiece in a non-contact manner using a fluid as a medium instead of an end effector that transports a thin plate-like workpiece such as a semiconductor wafer or a glass substrate has been proposed (Patent Document 1). In the Bernoulli chuck, an air injection port is provided in a holding plate arranged above the workpiece, and the workpiece is sucked toward the holding plate by the Bernoulli effect when air is flowed at a high speed between the upper surface of the workpiece and the holding plate surface. That is, the workpiece is held in a non-contact state with the holding plate at a position where the weight and the suction force are balanced.

JP-A-11-223521

  However, the Bernoulli chuck has a low holding force and requires a large flow rate to maintain the holding force. In addition, because the holding force is obtained by the Bernoulli effect of the air flowing between the workpiece upper surface and the holding plate surface, boundary layer separation and turbulent flow transition are likely to occur due to the deceleration flow accompanying pressure recovery, and the holding force is stable. There is a problem of not doing.

  An object of the present invention is to provide a small non-contact workpiece holding device having a stable high holding force with a small amount of energy.

  The non-contact workpiece holding device of the present invention has a rotationally symmetric inner peripheral surface, a housing in which a top portion is airtight and a circular lower opening is provided in a bottom portion, and a circumferential direction of the inner peripheral surface of the housing. And a flow path for jetting gas into the housing at a flow rate having a downward component to form a swirling flow, and the inner peripheral surface has a reduced diameter portion that is reduced in diameter toward the lower opening direction.

  Preferably, a block member is fitted into the top of the housing, and the flow path is formed in a spiral shape between the block member and the inner peripheral surface. At this time, for example, spiral ridges are provided on the outer peripheral surface of the block, and the spiral channels are formed by the ridges coming into contact with the inner peripheral surface. Thereby, a spiral flow path can be formed with a very simple configuration, and the assembly efficiency is also improved. Furthermore, in order to form a swirl flow more efficiently, it is preferable that the block member has a rotationally symmetric protrusion that is reduced in diameter toward the lower opening.

  For example, a control flow path that communicates the block member along the rotational symmetry axis is provided, and the control flow path is further communicated to the outside of the housing via the control valve. Thereby, the levitation force of the workpiece can be easily controlled. At this time, a supply flow path for supplying gas to the upper portion of the block member is hermetically connected to the housing, and for example, a control flow path is disposed inside the supply flow path. Thereby, the diameter of a non-contact workpiece holding apparatus can be made smaller.

  Furthermore, in order to suppress the separation and turbulence of the swirling flow flowing out from the lower opening, a region in which the lower opening expands downward may be provided. A plurality of spiral flow paths are provided, for example. Thereby, it becomes possible to form a stable swirl flow more efficiently.

  Furthermore, the non-contact work holding device unit according to the present invention is characterized in that an even number of the non-contact work holding devices are provided, and the number of the spiral-shaped flow paths that are clockwise is the same as the number of those that face left.

  In order to reduce the influence of the torque of the swirl flow on the work, it is preferable to alternately arrange the non-contact work holding devices having the right-handed and left-handed flow paths with rotational symmetry about one axis.

  ADVANTAGE OF THE INVENTION According to this invention, the small non-contact workpiece holding apparatus which has the stable high holding force with little energy can be provided.

It is a sectional side view of the non-contact workpiece holding device of this embodiment. It is a top view of the block member provided with two spiral ridges. It is a figure which shows the left half as sectional drawing of the non-contact workpiece holding apparatus of 2nd Embodiment. It is a layout of the non-contact work holding unit of the third embodiment showing the layout of the non-contact work holding device. It is another example of the layout of the non-contact workpiece holding unit of the third embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a configuration of a non-contact work holding device according to a first embodiment of the present invention.

  The non-contact work holding device 10 includes a housing 11 having a cylindrical shape, and the housing 11 is provided with a rotationally symmetric cavity 12 that communicates vertically along the cylindrical axis X. That is, a rotationally symmetric inner peripheral surface is formed in the housing 11.

  The cavity 12 includes a connecting part 12A, a spiral flow path forming part 12B, a reduced diameter part 12C, a swirl flow forming part 12D, and an opening part 12E in order from the top. The inner peripheral surface of the connecting portion 12A has a cylindrical shape with an inner diameter D1, and the inner peripheral surface of the spiral flow path forming portion 12B has a cylindrical shape with an inner diameter D2 that is slightly smaller than the inner diameter D1. The reduced diameter portion 12C has a cylindrical shape with an inner circumferential surface having an inner diameter D3 that is slightly smaller than the inner diameter D2, and a swirl flow forming portion 12D that has a smaller inner diameter D4 than the inner diameter D3. And a portion that gradually decreases along the cylindrical axis X (linearly decreases in the present embodiment). Further, the opening 12E is once slightly reduced in diameter from the swirl flow forming portion 12D, and then expanded to the substantially inner diameter D4 toward the lower end surface of the housing 11. In addition, it is also possible to make the swirl | flow flow formation part 12D into an opening part as it is, without performing the diameter expansion, or performing diameter reduction further.

  The block member 13 is fitted into the spiral flow path forming portion 12B. The block member 13 includes a cylindrical portion 13A and a frustoconical tip portion 13B, and a spiral ridge 14 is integrally provided on the outer peripheral surface of the cylindrical portion 13A. The outer diameter D5 of the cylindrical portion 13A is smaller than the inner diameter D2 of the spiral flow path forming portion 12B, and its height is substantially equal to the spiral flow path forming portion 12B. Further, the outer diameter of the spiral ridge 14 is substantially equal to the inner diameter D2 of the spiral flow path forming portion 12B, and when the block member 13 is fitted into the spiral flow path forming portion 12B, the lower end of the ridge 14 is spiral. The downward movement in the axial direction is restricted by engaging the step portion between the flow path forming portion 12B and the reduced diameter portion 13C. At this time, in a space sandwiched between the outer peripheral surface of the cylindrical portion 13A and the inner peripheral surface of the spiral flow path forming portion 12B, a spiral shape partitioned by the ridges 14 in contact with the inner peripheral surface of the spiral flow path forming portion 12B. A flow path is formed.

  In a state in which the cylindrical portion 13A is mounted on the spiral flow path forming portion 12B, the truncated conical tip portion 13B is disposed so as to protrude into the reduced diameter portion 12C, and the tip thereof is substantially the entrance height of the swirl flow forming portion 12D. Reach. At this time, a gap is formed between the outer peripheral surface (conical surface) of the tip portion 13B and the inner peripheral surface of the reduced diameter portion 12C.

  In addition, the fixing member 15 is airtightly fitted into the connecting portion 12 </ b> A, and the upper end portion of the spiral protrusion 14 of the block member 13 is engaged with the lower end portion of the fixing member 15. Furthermore, in this state, the axial movement of the upper end portion of the fixing member 15 is restricted by the C ring 16 fitted in an annular groove formed on the inner peripheral surface of the connecting portion 12A. Thereby, the block part 13 and the fixing member 15 are fixed to the housing 11 in the axial direction.

  Further, a screw hole that communicates with the upper and lower sides is provided in the center of the fixing member 15, and a connecting member 17 having a male screw is screwed into the screw hole in an airtight manner. The connecting member 17 is also formed with a passage 17A along the axis, and one end of a supply flow path 18 for supplying gas into the housing 11 is connected to the side opposite to the male screw. The other end of the supply flow path 18 is connected to a gas supply device (not shown) such as a pump, and high-pressure gas, for example, is supplied from the gas supply device to the housing 11.

  A control flow path 19 is disposed along the axis X inside the supply flow path 18. The control flow path 19 is extended to the outside of the supply flow path 18 at a predetermined position of the supply flow path 18, for example, and a control valve 20 is provided at the tip of the control flow path 19. Controlled by The control passage 19 passes through the inside of the passage 17 </ b> A of the connecting member 17, is formed at the center of the block member 13, and is hermetically fitted into a hole 13 </ b> D that penetrates the block member 13 along the axis X. That is, when the control valve 20 is opened, the center of the swirl flow forming portion 12 </ b> D is communicated with the outside of the housing via the control flow path 19.

  Next, the operation of the non-contact work holding device 10 of this embodiment will be described with reference to FIG. The non-contact work holding device 10 is used in opposition to a thin sheet work W arranged substantially horizontally. That is, the cylinder shaft X is set to be substantially vertical, and the opening 12E faces the workpiece W. The high-pressure gas supplied from the pump is supplied to the upper part of the block member 13 through the supply passage 18. The upper portion of the block member 13 is hermetically sealed with respect to the outside by the fixing member 15 and the connecting member 17, and a space 21 that covers the top surface of the block member 13 is formed.

  The gas supplied to the space 21 descends the spiral channel formed in the spiral channel forming part 12B and is ejected to the reduced diameter part 13. Since the gas is ejected along the spiral flow path, it is ejected at a flow velocity having a downward component corresponding to the spiral pitch along the circumferential direction of the inner circumferential surface of the reduced diameter portion 12C. The ejected gas descends while drawing a spiral in the space between the inner peripheral surface of the reduced diameter portion 12C and the outer peripheral surface of the tip end portion 13B of the block member 13, and as the diameter decreases, the gas decreases. The rotational speed of increases.

  In the swirl flow forming unit 12D, the swirl flow that has been speeded up descends in a spiral manner, and a stable swirl flow is formed. The swirl flow that has reached the lower end of the swirl flow forming portion 12D flows out of the housing 11 through the opening 12E, and flows out radially outward through a gap between the lower end surface of the housing 11 and the workpiece W. The control valve 20 is normally maintained in a closed state.

  In the swirl flow forming portion 12D where the swirl flow is sufficiently developed, the rotational speed distribution of the gas in the cylinder is constant, and negative pressure is generated in the center. At this time, the pressure distribution in the radial direction between the surface of the workpiece W and the housing 11 has a maximum negative pressure around the cylindrical axis X, and the pressure increases toward the outside, and the end surface of the housing 11 and the workpiece W are increased. In the gap with the surface, it swings to the positive pressure side. Then, the pressure converges to the outside air pressure outside the housing 11.

  Further, the levitation force due to the swirling flow of the workpiece W is a function of the distance between the workpiece W and the housing 11, and when the distance is a predetermined value, the weight of the workpiece W and the levitation force are balanced. In addition, this position is a stable balance point, and when the distance approaches further, the non-contact work holding device pushes down the work W, and when it moves away, the work is sucked up and pushed up. As described above, according to the present embodiment, a stable swirl flow can be formed in the housing 11, and the workpiece W can be held in a non-contact manner using the negative pressure obtained by the swirl flow.

  When the control valve 20 is opened, the swirling flow forming portion 12D communicates with the outside through the control passage 19, so that the pressure at the central portion of the swirling flow forming portion 12D increases due to the external air pressure, and the work levitation force decreases. Therefore, the holding of the workpiece W can be controlled by controlling the opening and closing of the control valve 20. In addition to introducing the atmospheric pressure, controllability can be further enhanced by actively sending gas from a pump or the like.

  As described above, according to the non-contact work holding device of the first embodiment, a stable swirl flow is formed in the housing, and, for example, a thin plate-like work is brought into non-contact using the negative pressure obtained by the swirl flow. It can be held and transported.

  Further, since the gas is ejected into the housing using the spiral passage, the swirl flow can be formed efficiently. Furthermore, in this embodiment, since the swirl flow is formed by reducing the diameter, a stable and high-speed swirl flow can be formed more efficiently, and a strong negative pressure can be generated in a small housing. Can do.

  In this embodiment, it is possible to form a spiral flow path simply by inserting the block portion, and the assembly efficiency is high. Further, the swirling flow can be generated more efficiently by disposing a tip portion whose outer diameter is reduced in accordance with the reduced diameter of the inner peripheral surface of the housing in the reduced diameter portion.

  Furthermore, in this embodiment, since a control passage that communicates the swirl flow forming portion with the outside via the control valve is provided, it is possible to control the opening and closing of the control valve without changing the output of the pump. It is possible to control the levitation force applied to the.

  In addition, in 1st Embodiment with reference to FIG. 1, although illustrated when the number of the protruding item | line provided in the outer periphery of a block member was one example, the number of an protruding item | line may be two or more. Moreover, it is also possible to have a configuration in which the outer peripheral surface of the block member remains the cylindrical surface and the ridges are provided on the inner peripheral surface of the spiral flow path forming portion. In addition, in FIG. 2, the top view in the case of providing the two convex strips 31A and 31B in an outer peripheral surface as the block member 30 as a modification (double helix) is shown. The spiral turning direction may be right-handed or left-handed.

  Next, a second embodiment of the present invention will be described with reference to FIG. The non-contact workpiece holding device of the second embodiment will be described. In addition, FIG. 3 is a figure which shows the left half of the axis | shaft X as sectional drawing of the non-contact workpiece holding apparatus of 2nd Embodiment.

  The non-contact work holding device 30 of the second embodiment includes a housing 31 corresponding to the housing 11 of the first embodiment. The cavity 32 formed in the housing 31 includes a connection part 32A, a spiral flow path forming part reduced diameter part 32B, a reduced diameter part 32C, a swirl flow forming part 32D, and an opening part 32E, which are substantially the same as in the first embodiment. However, the connecting tube 33 in which the fixing portion 15 and the connecting portion 17 of the first embodiment are integrated is screwed to the connecting portion 32A.

  That is, a male screw is provided in the vicinity of the tip inserted into the connecting portion 32A of the connecting pipe 33, and is screwed with a female screw provided on the inner peripheral surface of the connecting portion 32A. The connecting pipe 33 is integrally provided with a nut portion 33A for screwing work. Further, an airtight seal member (rubber packing or the like) 34 is interposed between the connection pipe 33 and the inner peripheral surface of the coupling portion 32A.

  On the other hand, the end of the connecting pipe 33 opposite to the side inserted into the connecting portion 32 </ b> A is connected to the T-shaped connecting pipe 35. The connecting pipe 33 is connected to a pipe corresponding to the T-shaped vertical bar of the T-shaped connecting pipe 35. For example, the connecting pipe 33 is inserted into the T-shaped connecting pipe 34, and an annular claw provided on the outer peripheral surface of the connecting pipe 33 is hooked on an annular groove provided on the inner peripheral surface of the T-shaped connecting pipe 35. Connected. In the example of FIG. 3, the connecting pipe 33 and the T-shaped connecting pipe 35 are connected by two sets of grooves and claws, and the connecting pipe 33 is integrated with the T-shaped connecting pipe 35 so as to be rotatable around the axis X. The An airtight seal member 36 is interposed between the outer peripheral surface of the connection pipe 33 and the inner peripheral surface of the T-shaped connection pipe 35. Further, the pipe corresponding to the T-shaped horizontal bar of the T-shaped connecting pipe 35 is provided with a mechanism for further connecting the pipe to both ends thereof. This connection mechanism may be of any known type.

  In the non-contact workpiece 30 of the second embodiment, the outer shape of the housing 31 includes a cylindrical fixing portion 31A having a relatively large diameter and a cylindrical tip portion 31B having a relatively small diameter. A male screw is provided on the outer peripheral surface of the portion 31. In the present embodiment, the male screw of the cylindrical tip portion 31B is used to fix and support the non-contact work holding device 30 on the plate member 40 in cooperation with the cylindrical fixing portion 31A. That is, the cylindrical tip portion 31B is inserted through the plate member 40 provided with a hole substantially equal to the outer diameter thereof, and then the nut 41 is screwed into the male screw of the cylindrical tip portion 31B. Accordingly, the plate member 40 is sandwiched between the cylindrical fixing portion 31A and the nut 41, and the non-contact work holding device is fixed to the plate member 40.

  As described above, also in the second embodiment, the same effect as that of the first embodiment can be obtained. Moreover, in 2nd Embodiment, a supply flow path can be connected to a housing only by screwing the connection pipe integrated with the T-shaped connection pipe. Further, as will be described in the following third embodiment, when a plurality of non-contact work holding devices are used, the supply flow paths of the respective non-contact work holding devices are continuously connected via a T-shaped connecting pipe. can do. Also, since the connecting pipe connected to the housing is rotatably engaged with the T-shaped connecting pipe, the connecting work with the housing can be easily performed, and the T-shaped connecting pipe can rotate freely with respect to the housing even after the connection. It becomes possible to do. Note that the non-contact workpiece holding device of the second embodiment can be combined with the modification of the first embodiment.

  4 and 5 are schematic views showing the arrangement of the non-contact work holding device unit according to the third embodiment of the present invention. In the third embodiment, a plurality of non-contact work holding devices of the first or second embodiment are used as a unit. In the example of FIG. 4, the spiral ridges provided on the block member use right-handed and left-handed non-contact holding devices 10 </ b> A and 10 </ b> B as a pair. Further, in the example of FIG. 5, three each of right-handed and left-handed are used, and these are arranged alternately on the right and left on the same circumference. In addition, it is the same as that of 1st Embodiment, 2nd Embodiment, or those modifications except the winding direction of a protruding item | line.

  As described above, also in the third embodiment, the same effect as in the first and second embodiments can be obtained, and by using a plurality of the workpieces, it is possible to hold and transport a larger and heavy workpiece. Further, by using the right-handed winding and the left-handed winding as a pair, the influence of the torque on the workpiece due to the swirling flow can be reduced.

DESCRIPTION OF SYMBOLS 10 Non-contact workpiece holding apparatus 11 Housing 12 Cavity 12A Connection part 12B Spiral flow path formation part 12C Reduced diameter part 12D Swirling flow formation part 12E Opening part 13 Block member 14 Spiral protrusion 15 Fixing member 17 Connection member 18 Supply flow path 19 Control Flow path 20 Control valve 21 Space

Claims (10)

  A housing having a rotationally symmetric inner peripheral surface, the top being hermetically sealed and having a circular lower opening at the bottom, and gas flowing at a flow rate having a downward component along the circumferential direction of the inner peripheral surface of the housing; A non-contact work holding device comprising: a flow path that ejects into a housing to form a swirling flow, and the inner peripheral surface includes a reduced diameter portion that decreases in diameter toward the lower opening direction.   The non-contact work holding device according to claim 1, wherein a block member is inserted into a top portion of the housing, and the flow path is formed in a spiral shape between the block member and the inner peripheral surface. .   3. The non-circular flow path according to claim 2, wherein spiral ridges are provided on an outer peripheral surface of the block, and the spiral flow paths are formed by the ridges coming into contact with the inner peripheral surface. Contact workpiece holding device.   The non-contact work holding apparatus according to claim 3, wherein the block member includes a rotationally symmetric protrusion that reduces in diameter toward the lower opening.   The non-contact according to claim 4, wherein a control flow path that communicates the block member along a rotational symmetry axis is provided, and the control flow path is further communicated to the outside of the housing via a control valve. Work holding device.   The supply flow path for supplying the gas to an upper portion of the block member is hermetically connected to a housing, and the control flow path is disposed inside the supply flow path. Non-contact work holding device.   The non-contact work holding apparatus according to claim 6, wherein the lower opening has a region whose diameter is increased downward.   The non-contact work holding device according to any one of claims 1 to 7, wherein a plurality of the spiral flow paths are provided.   A non-contact work holding device unit comprising an even number of non-contact work holding devices according to any one of claims 1 to 8, wherein the spiral flow path has a right-handed number and a left-handed one. Non-contact work holding device unit characterized in that the numbers are equal. The non-contact work holding device unit according to claim 9, wherein the non-contact work holding devices having the right-handed and left-handed flow paths are alternately arranged in a rotationally symmetrical manner about one axis.

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