JP2013146837A - Suction chuck and transfer device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suction chuck capable of eliminating the deviation of a repulsive force by a smooth air flow irrespective of a position of an exhaust hole.SOLUTION: A suction chuck 10 includes a flat plate-like body 11, an opposing surface 31, a plurality of air ejection ports 41, and a plurality of exhaust holes 42. A compressed air flow passage is formed in the body 11. The opposing surface 31 is a surface of the body 11 on a side opposite to a workpiece. The air ejection ports 41 are opened at the opposing surface 31 for ejecting compressed air supplied from the flow passage. The exhaust holes 42 are opened in the opposing surface 31 around the air ejection ports 41, and formed through the body 11 in the thickness direction. Each air ejection port 41 is formed as a columnar space, and provided with three nozzle flow passages 44 opened opposing the inside of the space. Each nozzle flow passage 44 ejects compressed air in the direction along an inner wall of the columnar space.

Description

  The present invention mainly relates to a configuration of a suction chuck for transporting a workpiece while holding the workpiece in a non-contact manner.

  Conventionally, a non-contact transfer device that employs a Bernoulli chuck that uses the Bernoulli effect to transfer a thin flat plate work (thin plate work) such as a solar battery wafer, a fuel cell, or a secondary battery electrode or separator. (See, for example, Patent Document 1).

  The non-contact conveyance device described in Patent Document 1 ejects air into a swirling flow forming body (suction element) formed in a hollow cylindrical shape, and forms a swirling flow inside the swirling flow forming body. It is configured. Since the swirling flow flows out from the swirling flow forming body as a high-speed flow, a negative pressure is generated between the end surface of the swirling flow forming body and the transferred object (wafer). Thus, the object to be conveyed is sucked and held without contact. In Patent Document 1, since the air blown into the swirling flow forming body is rectified as it is along the inner peripheral surface to become a swirling flow, it can be smoothly swirled without substantially receiving passage resistance. It is said that energy efficiency can be realized by improving energy efficiency.

  By the way, in a transfer apparatus that sucks and holds a thin plate workpiece (conveyed object), it is preferable to apply a suction force (negative pressure) to the workpiece as uniformly as possible. This is because if the suction force acting on the workpiece is uneven, vibration and deformation can occur in the workpiece. From this point of view, it is considered preferable to reduce the size of the suction element for generating the suction force as much as possible and increase the number of suction elements arranged per unit area.

  In this regard, the non-contact conveyance device described in Patent Document 1 is configured to form a fluid introduction port, a fluid passage, a jet port, and the like in the swirl flow forming body (suction element) formed in a hollow cylindrical shape. It is considered difficult to downsize the swirl flow forming body. Therefore, it is difficult to increase the number of swirling flow forming bodies arranged per unit area. Patent Document 1 also discloses a configuration in which a plurality of recesses and fluid passages are formed in a base of a non-contact conveyance device that is thinly formed into a plate shape, and a swirling flow is generated in the internal space of the recess. However, since this is a configuration in which the concave portions are arranged in the two arm portions, the suction force acting on the workpiece is generated only in the portions of the two arm portions. Therefore, with this configuration, the suction force cannot be applied uniformly to the entire surface of the workpiece.

  Therefore, the applicant of the present application has proposed a suction chuck 9 as shown in FIGS. 11 and 12 as Japanese Patent Application No. 2011-94215. This is because a flat suction chuck body formed by laminating metal plates is formed with a facing surface 31 that directly faces a workpiece and a plurality of air jets (suction elements) that open on the facing surface 31. ) 41 are arranged in an array. Inside the main body of the suction chuck 9, a nozzle flow path 44 for ejecting compressed air into the air ejection port 41 is formed. As shown in FIGS. 11 and 12, two nozzle channels 44 are formed for one air jet 41. The two nozzle channels 44 are formed so as to open on the inner wall of the air outlet 41 so that the phases are different from each other by 180 °. By ejecting air from the nozzle channel 44, the air can flow along the inner wall surface of the air ejection port 41. The air that flows along the inner wall surface of the air outlet 41 flows out of the air outlet 41 at a high speed, thereby generating a suction force.

  The air outlet 41, the nozzle channel 44, and the like can be formed by a method such as etching or punching on the metal plate, and can be easily reduced in size and density. For example, in the suction chuck 9 of FIG. 11, the diameter of the air ejection port 41 is set to 3 mm, for example. Thus, since the air ejection port 41 can be formed extremely small, the number of suction elements (air ejection ports 41) arranged per unit area can be increased. Then, as shown in FIG. 11, by forming a large number of the air outlets 41 in an array, a suction force can be uniformly applied to the entire surface of the work, and vibration and deformation of the work are prevented. be able to.

  Further, in the suction chuck 9 shown in FIG. 11, a plurality of exhaust holes 42 for discharging air are formed in the facing surface 31. The exhaust hole 42 is formed so as to penetrate the main body of the suction chuck 9 in the thickness direction. The air ejected from the air ejection port 41 is exhausted through the exhaust hole 42.

Japanese Patent No. 3981241

  By the way, in the non-contact conveyance apparatus which patent document 1 discloses, the circumference | surroundings of a suction element (swirl flow formation body) are spaces. In this configuration, the air ejected from the suction element is quickly discharged toward the space. Therefore, in the configuration of Patent Document 1, it is unlikely that the flow of air ejected from the suction element is stagnant.

  On the other hand, in the suction chuck 9 of the comparative example shown in FIG. 11, the air ejected from each air ejection port 41 flows to the exhaust hole 42 and is discharged from the exhaust hole 42. Here, if the air does not flow smoothly from the air outlet 41 to the exhaust hole 42, the flow velocity is lowered and the suction force can be reduced. Therefore, in the suction chuck 9 having the configuration shown in FIG. 11, it is important to smoothly flow air from the air ejection port 41 to the exhaust hole 42.

  Based on the above viewpoints, the inventors of the present application have found the following problems as a result of repeating experiments and analysis by computer simulation.

  First, FIG. 13 shows the results obtained by computer simulation of the air stream ejected from the air ejection port 41 of the suction chuck 9 of the comparative example shown in FIG. This computer simulation is obtained by setting the diameter of the air ejection port 41 to 3 mm. Note that ΔZ in FIG. 13 indicates the distance between the facing surface 31 of the suction chuck 9 and the workpiece. It can be seen that the air flow changes as the suction chuck 9 approaches the workpiece. The state where ΔZ = 0.1 mm is the most stable state, and the workpiece is sucked and held by the suction chuck 9 in this state.

  According to the technique disclosed in Patent Document 1, the air blown into the swirling flow forming body included in the configuration of Patent Document 1 is rectified as it is along the inner peripheral surface to generate a swirling flow. However, as is clear from the results of the computer simulation in FIG. 13, in the suction chuck 9 of the comparative example, the air ejected from the nozzle flow path 44 is ejected to the outside with almost no swirling in the air ejection port 41. ing. This is because the suction chuck 9 of the comparative example (FIG. 11) has an air jet 41 that is extremely small (3 mm in diameter), so that the swirl component of the air flow is extremely small inside the air jet 41, and the air flow Is considered to be because it does not turn sufficiently. If the air does not sufficiently swirl inside the air outlet 41, the air ejected from the nozzle flow path 44 flows out from the air outlet 41 with almost no dispersion. As a result, the ejection direction of the air from the air ejection port 41 is concentrated in a specific direction. In the case of the suction chuck of the comparative example shown in FIG. 13, since the two nozzle flow paths 44 are provided in each air jet 41, the direction of the air flowing out from the air jet 41 is concentrated in two directions. doing.

  As shown in the comparative example (a) of FIG. 13, the air ejected in two directions from the air ejection port 41 flows to the exhaust hole 42 while drawing a trace that largely detours. In the case of the comparative example (a) in FIG. 13, it can be seen that the air flows largely detoured especially when ΔZ = 0.3 mm and ΔZ = 0.2 mm. Further, when ΔZ = 0.2 mm and ΔZ = 0.1 mm, it can be seen that a large loop-like flow is generated and the air flow is stagnant.

  Thus, the simulation conducted by the inventors of the present application revealed that air does not flow smoothly in the suction chuck 9 of the comparative example of FIG. Since air does not flow smoothly, there is a concern about a reduction in suction force. Therefore, the inventors of the present application obtained a pressure distribution around the air outlet 41 shown in the comparative example (a) of FIG. 13 by computer simulation. The results are shown in the comparative example (a) in FIG. FIG. 14 shows a pressure distribution in a state where ΔZ = 0.1 mm (a state where the workpiece is sucked and held with respect to the suction chuck 9). The shades of color in FIG. 14 indicate the magnitude of the attractive force. The darker the color, the stronger the repulsive force (repulsive force). Further, the light-colored (white) portion indicates the suction force, and the intermediate gray indicates the atmospheric pressure (= zero suction force). Note that the vicinity of the nozzle flow path 44 is the portion where the flow velocity is the fastest, and a negative pressure is generated when the jet swirls along the cylindrical surface in the air outlet 41, so this vicinity always becomes a suction force. Further, since the exhaust hole 42 communicates with the atmospheric pressure, the force generated in this portion is substantially zero. Therefore, the distribution of the repulsive force in a region other than the air outlet 41 and the exhaust hole 42 (region around the air outlet 41) becomes a problem.

  From the simulation result of FIG. 14, it can be seen that the repulsive force around the air outlet 41 is not uniform. The suction chuck 9 of this comparative example has a very small air jet 41 itself, and is formed by arranging the air jets 41 in an array, so that the suction force and the repulsive force are compared with the configuration of Patent Document 1. Can be distributed at a fine pitch. Therefore, even if the repulsive force is non-uniform around the air ejection port 41, the repulsive force can be applied to the workpiece more uniformly than the configuration of Patent Document 1 when viewed as a whole of the suction chuck 9. It can be said. However, when handling a thin wafer-like workpiece, there is a concern that the distribution of the repulsive force around the air jet 41 may cause deformation or vibration of the workpiece. Therefore, there is room for improvement even with such a non-uniform repulsive force.

  The inventors of the present application have considered that the reason why the repulsive force is biased as described above is that air does not flow smoothly from the air outlet 41 to the exhaust hole 42 and the air is stagnant. Such air stagnation can be improved by optimizing the position of the exhaust hole 42. The result of the computer simulation when the position of the exhaust hole 42 is optimized is shown as a comparative example (b) in FIG. 13 and as a comparative example (b) in FIG.

  As can be seen from the results of the computer simulation, by optimizing the position of the exhaust hole 42 (comparative example (b)), the air flow becomes slightly smoother than before the optimization (comparative example (a)). Also, the bias of repulsive force has been improved slightly. However, as can be seen from the comparative example (b) in FIG. 13, even when the position of the exhaust hole is optimized, the looped flow of air remains, and the stagnation of the air cannot be completely eliminated. . Further, as can be seen from the comparative example (b) in FIG. 14, the bias of the repulsive force cannot be completely eliminated.

  Further, in the actual suction chuck 9, there is a problem that the exhaust hole 42 cannot always be formed at an optimal position. This is because a flow path for supplying compressed air to the air outlet 41 needs to be formed inside the suction chuck 9, and the exhaust hole 42 must be formed avoiding this flow path. Further, when the exhaust hole 42 is to be formed at an optimal position, the degree of freedom in design of the suction chuck 9 is lowered, so that it is difficult to freely design, for example, to arrange a sensor at an arbitrary position.

  Thus, with the idea of optimizing the position of the exhaust hole 42, it is insufficient or impossible to eliminate the bias of the repulsive force around the air outlet 41. Therefore, a configuration that can effectively equalize the repulsive force around the air outlet 41 is required.

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a suction chuck in which the bias of the repulsive force is eliminated by smoothly flowing air regardless of the position of the exhaust hole. .

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to an aspect of the present invention, the following configuration of a suction chuck that sucks and holds a thin flat plate-like workpiece in a non-contact state is provided. That is, the suction chuck includes a flat plate-shaped main body, an opposing surface, a plurality of jet ports, and a plurality of exhaust holes. A compressed gas flow path is formed inside the main body. The facing surface is a surface of the main body that faces the workpiece. The jet port opens in the facing surface in order to jet the compressed gas supplied from the flow path. The exhaust hole is formed so as to open to the facing surface around the ejection port and to penetrate the main body in the thickness direction. Each jet outlet is formed as a cylindrical space, and includes three nozzle channels that open to the inside of the space, and each nozzle channel supplies compressed gas in a direction along the inner wall of the cylindrical space. Erupts.

  As described above, by supplying the compressed gas from the three nozzle flow paths into the ejection port, the flow of the compressed gas ejected from the ejection port is dispersed in three directions. Since the flow of the compressed gas is dispersed in three directions, the influence of the position of the exhaust hole on the flow of the compressed air is reduced. As a result, the exhaust hole can be freely arranged and the degree of freedom in design is improved. Further, since the flow of compressed air is dispersed, the pressure distribution is made uniform, so that vibration and deformation of the workpiece can be prevented. Moreover, since the flow rate of the compressed gas per nozzle flow path decreases by increasing the number of nozzle flow paths, it is possible to reduce the impact received by the work due to the ejection of air.

  In the above suction chuck, it is preferable that the openings of the three nozzle flow paths are formed at equal intervals in the circumferential direction of the ejection port.

  As described above, by supplying the compressed gas from the nozzle passages opened at equal intervals into the ejection port, the compressed gas ejected from the ejection port can be uniformly dispersed in three directions.

  In the above suction chuck, it is preferable that the longitudinal direction of the nozzle channel is formed in parallel to the facing surface.

  Thereby, the compressed gas ejected from the ejection port can flow smoothly along the opposing surface.

  In the above suction chuck, it is preferable that at least three exhaust holes in the vicinity of the jet port are formed on a concentric circle centered on the jet port.

  Thereby, the compressed gas which is dispersed and ejected in three directions from the ejection port can be smoothly exhausted from the exhaust hole.

  In the above suction chuck, it is preferable that the exhaust holes nearest to the jet port are formed at equal intervals on the concentric circles.

  Thereby, since compressed gas can be disperse | distributed uniformly and it can flow to an exhaust hole, the pressure distribution around a jet nozzle can be equalized further.

  In the above suction chuck, the flow direction of the compressed gas around the axis of the jet port in the inner space of the arbitrary jet port is opposite to the other jet ports formed in the vicinity of the jet port. The suction chuck is characterized in that the nozzle channel is formed as described above.

  Thereby, it is possible to cancel the torque generated by the compressed gas flowing so as to swirl within the ejection port, and to suppress the rotation of the workpiece sucked and held by the suction chuck. Furthermore, if the number of jets whose flow direction is clockwise and the number of jets whose flow direction is counterclockwise (reverse) are the same, the rotational moment generated by each suction element with respect to the rotation center of the workpiece The total becomes zero, and the rotation of the workpiece sucked and held by the suction chuck can be suppressed more effectively. Furthermore, one or more regulating members that contact the side surface of the workpiece sucked and held by the suction chuck to prevent rotation may be provided around the suction chuck.

  According to another aspect of the present invention, there is provided a transfer apparatus including the above suction chuck and a parallel mechanism capable of moving the suction chuck three-dimensionally within a predetermined range.

  That is, the parallel mechanism allows the workpiece sucked and held by the suction chuck to be freely moved three-dimensionally. According to the suction chuck of the present invention, a thin flat plate-like workpiece can be sucked and held while suppressing vibration and deformation. Therefore, the transfer device described above can prevent the workpiece from being deformed or damaged. It can be moved to any position.

The perspective view of the transfer robot provided with the suction chuck which concerns on one Embodiment of this invention. The perspective view which mainly shows the lower surface side (opposite surface) of a suction chuck. FIG. 3 is a schematic cross-sectional view of a suction chuck. The perspective view which shows the mode of a nozzle flow path transparently. The top view which shows the opposing surface of a suction chuck. The top view which shows a mode that air blows off from an air jet nozzle. (A) The figure which shows the result of having calculated | required the air trace in the suction chuck of embodiment by computer simulation. (B) The figure which shows the result of having changed the position of the exhaust hole and performing the same simulation. (A) The figure which shows the result of having calculated | required the pressure distribution in the suction chuck of embodiment by computer simulation. (B) The figure which shows the result of having changed the position of the exhaust hole and performing the same simulation. The figure which shows the result of having measured the relationship between the air flow rate and suction force of a suction chuck by experiment. The figure which shows the result of having measured the deformation amount of the workpiece | work attracted | sucked by the suction chuck by experiment. The top view of the suction chuck of a comparative example. The perspective view which shows transparently the mode of the nozzle flow path of the suction chuck of a comparative example. (A) The figure which shows the result of having calculated | required the air trace in the suction chuck of a comparative example by computer simulation. (B) The figure which shows the result of having changed the position of the exhaust hole and performing the same simulation. (A) The figure which shows the result of having calculated | required the pressure distribution in the suction chuck of a comparative example by computer simulation. (B) The figure which shows the result of having changed the position of the exhaust hole and performing the same simulation. The top view which shows the modification of the suction chuck of this invention.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a transfer robot (transfer apparatus) 1 including a suction chuck 10 according to an embodiment of the present invention.

  This transfer robot 1 is configured as a so-called parallel mechanism robot. Specifically, this transfer robot includes a base portion 101, three arms 106, three electric motors 104, and one end plate 114.

  A mounting surface P <b> 1 is formed on the lower surface of the base portion 101. On the other hand, the upper surface of the frame (not shown) for mounting the transfer robot 1 is a horizontal upward mounting surface. With this configuration, the transfer robot 1 can be installed in a suspended manner by fixing the mounted surface P1 of the base portion 101 to the mounting surface of the frame.

  Three electric motors 104 are fixed to the lower surface side of the base portion 101 so as to be arranged at equal intervals in the circumferential direction around the central portion of the base portion 101 in plan view. Each electric motor 104 has a speed reducer, and a base end portion of the arm 106 is fixed to an output shaft (that is, an output shaft of the speed reducer).

  A joint portion 110 made of a ball joint is provided in the middle of each arm 106, and the arm 106 can be bent at the joint portion 110. The tips of the three arms 106 are connected to one end plate 114. In addition, a motor 32 having a motor shaft facing downward is fixed to the base portion 101. The motor shaft of the motor 32 and the end plate 114 are connected by a turning shaft 33 that can transmit the rotation of the motor shaft to the end plate 114.

  As described above, the parallel mechanism is configured, and the transfer robot 1 can freely move the end plate 114 in a three-dimensional manner within the range of the stroke of the arm 106 by appropriately controlling the three electric motors 104. It can be made to.

  A suction chuck (Bernoulli chuck) 10 according to the present embodiment is attached to the lower surface of the end plate 114. Thereby, the transfer robot 1 of the present embodiment can move the suction chuck 10 three-dimensionally within the range of the stroke of the arm 106. As will be described in detail later, the suction chuck 10 generates a suction force between its lower surface and a surface facing the lower surface of the workpiece 90 (see FIG. 3) by supplying compressed air (compressed gas). The apparatus is capable of sucking and holding the workpiece in a non-contact manner.

  The transfer robot 1 of the present embodiment supplies compressed air to the suction chuck 10 to suck and hold the workpiece 90, and in that state, appropriately controls the electric motor 104 to suck the end plate 114 (and the workpiece 90). The suction chuck 10) is moved to a desired position. In addition, the transfer robot 1 can rotate the suction chuck 10 and rotate the workpiece 90 sucked and held by the suction chuck 10 in a substantially horizontal plane by appropriately driving the motor 32. Next, the transfer robot 1 places the workpiece 90 in a desired position by interrupting the supply of compressed air to the suction chuck 10 and releasing the suction holding of the workpiece 90. As described above, the transfer robot 1 of the present embodiment can hold the workpiece 90 by the suction chuck 10 and move it to a desired position.

  The workpiece 90 handled by the transfer robot 1 of the present embodiment is assumed to be a thin flat plate, particularly a rectangular one. Examples of the workpiece 90 include, but are not limited to, a solar battery wafer, a fuel cell, a secondary battery electrode, a separator, and a silicon wafer.

  Next, the configuration of the suction chuck 10 of this embodiment will be described in detail.

  As shown in FIG. 2, the suction chuck 10 includes a main body 11 that is configured in a flat plate shape as a whole. As shown in FIG. 3, the lower surface of the main body 11 is a facing surface 31 that can directly face the workpiece 90. The facing surface 31 is configured as a rectangular (perpendicular quadrilateral) flat surface perpendicular to the thickness direction of the suction chuck 10. As shown in FIG. 2, an air outlet 41 for ejecting air and a plurality of exhaust holes 42 for exhausting air are formed in an array on the facing surface 31 of the suction chuck 10.

  As shown in FIG. 3, the main body 11 of the suction chuck 10 is configured by stacking a plurality of plates in the thickness direction. Specifically, the main body 11 includes a surface plate 25, a nozzle plate 26, a connection plate 27, and a distribution plate 28 in order from the side closer to the workpiece 90 (lower side). The lower surface of the surface plate 25 constitutes the facing surface 31.

  The air ejection port 41 is a cylindrical space, and is formed as a round hole that penetrates the surface plate 25 and the nozzle plate 26 in the thickness direction. The air outlet 41 is not formed in the connection plate 27 and the distribution plate 28. That is, one end portion (upper end portion) of the air ejection port 41 in the thickness direction of the suction chuck 10 is sealed by the connection plate 27. On the other hand, the other end (lower end) of the air outlet 41 is open to the lower surface (opposing surface 31) of the surface plate 25.

  As shown in FIG. 3, the nozzle plate 26 is formed with a nozzle flow path 44 communicating with the air ejection port 41. Specifically, the nozzle flow path 44 is configured as an elongated slit formed in the nozzle plate 26. As shown in FIGS. 4 and 5, the nozzle channel 44 is formed so that the longitudinal direction thereof substantially coincides with the tangential direction of the air ejection port 41, and one end side in the longitudinal direction is the air ejection port 41. It is comprised so that it may connect to the space inside.

  In the present embodiment, three nozzle channels 44 are formed for one air outlet 41. As shown in FIG. 5, the three nozzle flow paths 44 are formed so as to have a phase difference of 120 ° with respect to the central axis of the air ejection port 41. Accordingly, the three nozzle flow paths 44 are opened at equal intervals in the circumferential direction of the air outlet 41 with respect to the inner peripheral wall of the air outlet 41. Further, the longitudinal direction of the nozzle channel 44 is formed to be parallel to the facing surface 31. For convenience of illustration, in the cross-sectional view of FIG. 3, the two nozzle flow paths 44 are depicted as facing each other in the same cross-section, but this is a schematic diagram for explanation, In this way, the nozzle flow path 44 is not formed.

  As shown in FIGS. 3 to 5, the end of the nozzle channel 44 opposite to the air outlet 41 in the longitudinal direction is connected to the compressed air supply port 35. As a result, the air outlet 41 and the compressed air supply port 35 communicate with each other via the nozzle channel 44. As shown in FIG. 3, the compressed air supply port 35 is formed as a round hole that penetrates the nozzle plate 26 and the connection plate 27 in the thickness direction. The compressed air supply port 35 is formed corresponding to each nozzle flow path 44. That is, three compressed air supply ports 35 are formed in the nozzle plate 26 and the connection plate 27 with respect to one air outlet 41.

  As shown in FIG. 3, a distribution path 43 communicating with the three compressed air supply ports 35 is formed in the distribution plate 28. The distribution path 43 is connected to an appropriate compressed air source (for example, a compressor) via, for example, a joint 71 and a pipe 72 and an electromagnetic valve (not shown).

  The exhaust hole 42 is formed as a round hole and is formed so as to penetrate the plates 25, 26, 27, 28 in the thickness direction. That is, the exhaust hole 42 is formed so as to penetrate the main body 11 of the suction chuck 10 in the thickness direction. Accordingly, in the thickness direction of the suction chuck 10, one end portion of the exhaust hole 42 is open to the facing surface 31, and the other end portion is open to the upper surface of the main body 11 of the suction chuck 10.

  As shown in FIG. 5, in the present embodiment, the exhaust holes 42 are formed at equal intervals at positions that constitute the vertices of an equilateral triangle. Each air jet 41 is formed so as to be located at the center of gravity of an equilateral triangle formed by the three exhaust holes 42. As a result, the three exhaust holes 42 nearest to each air outlet 41 are arranged at equal intervals on a concentric circle centered on the air outlet 41. However, this does not apply to the air outlet 41 near the edge of the main body 11. This is because the exhaust hole 42 cannot be formed at the edge of the main body 11 (see FIG. 5).

  As the material of the four plates 25 to 28, it is preferable to use a metal from the viewpoint of cost and the like. Specific examples of the material of the plates 25 to 28 include those selected from stainless steel, aluminum alloy, or titanium alloy. And the main body of the suction chuck 10 is comprised by carrying out the diffusion joining in the state which accumulated all the four plates 25-28. In order to provide the suction chuck 10 with small distortion and good dimensional accuracy, it is preferable to use the same material for the four plates 25 to 28. This is because, when different types of metals are diffusion bonded, deformation such as deflection may occur due to residual strain after bonding. In the present embodiment, stainless steel is used as the material for the four plates 25 to 28.

  The air jets 41, the nozzle channels 44, the compressed air supply ports 35, the distribution channels 43, the exhaust holes 42 and the like formed in the four plates 25 to 28 may be formed by etching, for example. You may form by machining, such as punching and a drill. Since a processing method such as etching can be used, it is easy to form the air outlets 41, the nozzle channels 44, and the like in a small size in an array. For example, in this embodiment, the diameter of the air outlet 41 is about 3 mm.

  Next, the operation of the suction chuck 10 of the present embodiment configured as described above will be described with reference to FIG.

  In order to suck and hold the workpiece 90 by the suction chuck 10 having the above-described configuration, the electromagnetic valve connected to the compressed air source is opened, and supply of compressed air to the distribution path 43 is started. Thereby, compressed air is distributed from the distribution path 43 to the three compressed air supply ports 35. The compressed air supplied to the compressed air supply port 35 flows through the nozzle flow path 44 communicating with the compressed air supply port 35, and from the end of the nozzle flow path 44 toward the inside of the air ejection port 41. Erupts.

  As described above, each nozzle flow path 44 is formed so that the longitudinal direction thereof is along the tangential direction of the air ejection port 41, so that the air ejected from the three nozzle flow paths 44 flows from the air ejection port 41. It flows along the inner peripheral wall (see FIG. 6). Thereby, air flows so that it may turn in the air jet nozzle 41 (for example, in FIG. 6, air is flowing counterclockwise in the air jet nozzle 41). However, in the suction chuck 10 of the present embodiment, the air ejection port 41 is as small as 3 mm in diameter and is formed shallower than the diameter, so that the air does not completely swirl inside the air ejection port 41. . Accordingly, the air ejected from the nozzle flow path 44 into the air ejection port 41 is ejected from the air ejection port 41 to the extent that the direction is slightly changed in the air ejection port 41 (FIG. 6).

  Here, as shown in FIG. 3A, when the workpiece 90 is far away from the facing surface 31, no suction force is generated between the suction chuck 10 and the workpiece 90.

  However, when the facing surface 31 is brought closer to the workpiece 90 as shown in FIG. 3B, negative pressure due to the air ejected from the air ejection port 41 acts on the workpiece 90. As the distance between the facing surface 31 and the workpiece 90 becomes shorter, the flow velocity of the air flowing between the facing surface 31 and the workpiece 90 increases and is discharged upward through the exhaust hole 42. As a result, when the air flow traveling along the inner wall surface of the air ejection port 41 is discharged to the opposing surface 31, the flow velocity increases and the internal pressure of the air ejection port 41 decreases. The workpiece 90 is attracted to the facing surface 31 by the negative pressure generated at this time. On the other hand, since there is an air layer formed by the jet air from the air outlet 41 between the workpiece 90 and the facing surface 31, the workpiece 90 receives a repulsive force in a direction away from the facing surface 31. Therefore, the work 90 is not completely sucked against the facing surface 31. Due to the balance between the suction force and the repulsive force, the workpiece 90 is held in non-contact with the suction chuck 10. As described above, the air outlet 41 functions as a suction element that sucks and holds the workpiece 90 in contact with the suction chuck 10.

  The air that has flowed between the facing surface 31 and the workpiece 90 is discharged above the suction chuck 10 through the exhaust hole 42 (see FIG. 3B). Thereby, since air does not stay between the opposing surface 31 and the workpiece | work 90, air can be flowed smoothly and a suction force can be made to act efficiently.

  As described above, the air ejected from the nozzle flow path 44 into the air ejection port 41 flows so as to swirl along the inner peripheral wall of the air ejection port 41, so that torque acts on the workpiece 90 at this time. Therefore, in the suction chuck 10 of the present embodiment, as shown in FIG. 5, the direction of the nozzle flow path 44 that supplies compressed air to each air outlet 41 is opposite to the other air outlets 41 in the vicinity. It is formed to become. That is, each nozzle flow path 44 is formed so that the air flow direction between the air outlets 41 adjacent to each other in the vicinity is alternately arranged clockwise, counterclockwise, clockwise. Yes. Thereby, it is possible to cancel the torque generated by the swirling air and prevent the workpiece 90 sucked and held by the suction chuck 10 from rotating.

Furthermore, if the number of air jets 41 whose flow direction is clockwise and the number of air jets 41 whose flow direction is counterclockwise (opposite) are the same, rotation of the workpiece 90 generated by each suction element The sum of the rotational moments at the center becomes zero, and the rotation of the workpiece 90 sucked and held by the suction chuck 10 can be suppressed more effectively.

  As described above, the suction chuck 10 of this embodiment sucks and holds the surface of the workpiece 90 in the normal direction in a non-contact manner. However, with the above configuration alone, the workpiece 90 cannot be held in a direction parallel to the surface of the workpiece 90 (a direction parallel to the facing surface 31). Therefore, when the workpiece 90 is transported by attaching the suction chuck 10 to a transfer robot such as a parallel mechanism, a regulating member for regulating the movement of the workpiece 90 in the lateral direction is required. In view of this, an unillustrated regulating member is disposed around the suction chuck 10 of the present embodiment. Such a regulating member (guide member) is described in paragraph 0106 of Japanese Patent Application No. 2011-94215.

  For example, a plurality of guide members arranged at intervals from each other so as to surround the suction chuck 10 are fixed to the edge of the suction chuck 10. Two guide members are arranged on each side of the suction chuck 10 formed in a rectangular shape, and are arranged to face each other with the suction chuck 10 interposed therebetween. The guide member is disposed so as to be perpendicular to the thickness direction of the suction chuck 10 formed in a flat plate shape, and the lower end of the guide member projects downward from the lower surface (opposing surface 31) of the suction chuck 10. These guide members restrict relative movement of the workpiece 90 in a direction parallel to the lower surface (opposing surface 31) of the suction chuck 10 when the workpiece 90 held by the suction chuck 10 is conveyed.

  Subsequently, a specific effect obtained by the suction chuck of the present embodiment will be described.

  First, in order to verify the effect of the suction chuck 10 of the present embodiment, the inventors of the present application obtained the air flow from the air ejection port 41 by computer simulation. The result is shown in FIG. In this simulation, the equivalent hydraulic diameter x3 of the nozzle channel 44 is set to be equal to the equivalent hydraulic diameter x2 of the nozzle channel 44 of the suction chuck 9 of the comparative example when the simulation of FIG. 13 is performed. ing. Thereby, the simulation result (FIG. 13) about the suction chuck 9 (FIG. 11) of the comparative example provided with the two nozzle channels 44 and the suction chuck 10 of the present embodiment including the three nozzle channels 44 are obtained. The simulation result (FIG. 7) can be compared under the same conditions. In this way, the suction chuck 10 of this embodiment in which the equivalent hydraulic diameter of the nozzle flow path 44 is set to be equivalent to that of the suction chuck 9 of the comparative example may be referred to as type A. The diameter of the air outlet 41 is 3 mm.

  As shown in FIG. 7A, in the suction chuck 10 of the present embodiment, the air ejected from the air ejection port 41 is ejected in three directions. That is, compared with the suction chuck 9 of the comparative example (the simulation result of FIG. 13) in which air is concentrated in two directions, the air can be dispersed and ejected from the air ejection port 41. As a result, the air is not greatly detoured and flows unlike the suction chuck 9 of the comparative example, and the air from the air outlet 41 is smoothly directed toward the exhaust hole 42 as shown in FIG. I was able to flow. Compared to the simulation result of the suction chuck 9 of the comparative example shown in FIG. 13, the simulation result of the suction chuck of the present embodiment shown in FIG. It is decreasing and it turns out that the stagnation of air has decreased. In particular, in a state where the workpiece is sucked and held (a state where ΔZ = 0.1), the loop-like flow is almost disappeared. That is, according to the suction chuck 10 of the present embodiment, it has become clear that the workpiece 90 can be sucked and held in a state in which air is smoothly flowed without stagnation.

  Next, in order to verify the uniformity of the suction force generated by the suction chuck 10 of the present embodiment, the inventors of the present application obtained the pressure distribution around the air ejection port 41 by computer simulation. The result is shown in FIG. FIG. 8 shows the pressure distribution when ΔZ = 0.1 mm in FIG. 7 (the state in which the workpiece 90 is sucked and held). As shown in FIG. 8A, in the suction chuck 10 of this embodiment, the distribution of the repulsive force around the air ejection port 41 is uniform, compared with the suction chuck 9 of the comparative example (simulation result of FIG. 14). The difference is clear. That is, according to the suction chuck 10 of the present embodiment, the air ejected from the air ejection port 41 can be dispersed in three directions, so that the suction chuck 9 of the comparative example in which air is concentrated in two directions is ejected. In contrast, the repulsive force can be uniformly applied to the periphery of the suction force generated in the air jet outlet and in the vicinity of the edge. As described above, the suction chuck 10 of the present embodiment can uniformly apply the suction force and the repulsive force distributed substantially uniformly around the work 90 to the work 90 for each air outlet. The effect of reducing vibration and deformation can be expected.

  In addition, as shown in FIG. 6, the simulation results of FIG. 7A and FIG. 8A show that the exhaust holes 42 are respectively formed at the tip of the direction in which the air is ejected from the air outlet 41 in three directions. The case is assumed. As described above, by arranging the exhaust hole 42 at the tip of the air jetting direction from the air jetting port 41, the air from the air jetting port 41 can flow most smoothly. However, the exhaust holes 42 cannot always be formed with such an ideal arrangement. Therefore, the inventors of the present application performed the computer simulation similar to the above by arranging the exhaust hole 42 so that the air flowing out from the air jet port 41 does not flow easily. The results are shown in FIGS. 7 (b) and 8 (b).

  As shown in FIG. 7B, by changing the position of the exhaust hole 42, the air flow slightly changes. For example, when ΔZ = 0.3, a slight loop-like flow is generated. However, in a state where the workpiece is sucked and held (a state where ΔZ = 0.1), the loop-like flow is almost disappeared, and it can be seen that the air flows smoothly without stagnation. Further, as shown in FIG. 8B, even when the position of the exhaust hole 42 is changed, the pressure distribution around the air outlet 41 is uniform, and the exhaust hole 42 is brought to an ideal position. When compared with the case (FIG. 8A), a result comparable to that obtained is obtained. Thus, according to the suction chuck 10 of the present embodiment, it was confirmed that the pressure distribution can be made uniform by flowing air smoothly regardless of the arrangement of the exhaust holes 42.

  In this respect, in the suction chuck 9 of the comparative example shown in FIG. 11 and FIG. 12, the air from the air outlet 41 is concentrated and ejected in two directions, so that the air flow varies greatly depending on the position of the exhaust hole 42. End up. For this reason, in the suction chuck 9 of the comparative example, the exhaust holes 42 cannot be freely arranged, and the degree of design freedom is low. In the suction chuck 10 of the present embodiment, air from the air outlet 41 is dispersed and ejected in three directions, so that the air flow does not change greatly even if the position of the exhaust hole 42 is changed. That is, even if the position of the exhaust hole 42 is changed from the ideal position, the air flow does not change greatly, so that the air can flow smoothly as in the ideal state, and the repulsive force acts uniformly. be able to. Therefore, according to the configuration of the suction chuck 10 of the present embodiment, the exhaust holes 42 can be freely arranged without worrying about the air flow, so that the degree of freedom in designing the suction chuck 10 can be improved.

  Subsequently, the inventors of the present application actually made a prototype of the suction chuck 10 as shown in FIG. 2, and compared the suction force acting on the workpiece with the suction chuck 9 (FIG. 11) of the comparative example. Went. The result is shown in FIG. In FIG. 9, the horizontal axis represents the flow rate of air supplied to the suction chuck, and the vertical axis represents the suction force that the entire suction chuck acts on the workpiece. The graph labeled 2 nozzles in FIG. 9 shows the experimental results for the suction chuck 9 of the comparative example. In addition, the graphs indicated as type A and type B show the experimental results for the suction chuck 10 of this embodiment (a suction chuck having three nozzle channels with respect to one air jet port).

  As described above, the type A suction chuck is set so that the equivalent hydraulic diameter of the nozzle channel 44 is equivalent to the suction chuck 9 of the comparative example. On the other hand, in the suction chuck of the present embodiment indicated as type B in FIG. 9, the total cross-sectional area of the three nozzle flow paths 44 is the total cut-off of the two nozzle flow paths 44 of the suction chuck 9 of the comparative example. It is set to be equal to the area. In this experiment, the conditions of the suction chuck of the present embodiment and the suction chuck of the comparative example are matched as much as possible, so that the diameter and number of the air ejection ports 41 and the total opening area of the exhaust holes 42 are approximately equal. It is set to be.

  As shown in FIG. 9, the suction chuck 10 (type A and type B) of this embodiment has improved suction force at the same air flow rate as compared to the suction chuck 9 of the comparative example. This is because the suction chuck 10 according to the present embodiment is able to generate a suction force efficiently with a small air flow rate as a result of allowing air to flow smoothly from the air outlet 41 to the exhaust hole 42. Conceivable. As described above, the suction chuck 10 of the present embodiment having three nozzle channels 44 for one air jet 41 has two nozzle channels 44 for one air jet 41. It was confirmed that the suction efficiency was improved as compared with the suction chuck 9 of the comparative example.

  Subsequently, the inventors of the present application conducted an experiment in which a thin chuck-like workpiece 90 was actually sucked and held by a suction chuck and the deformation amount of the workpiece 90 was measured. The workpiece used in this experiment is a silicon wafer having a square of 125 mm across and four corners with a corner drop portion of about 8 mm, the diagonal length is about 165 mm, and the thickness is 110 μm. Is. The result of this experiment is shown in FIG. The horizontal axis in FIG. 10 indicates the distance from the center position of the workpiece 90 in the diagonal direction of the workpiece 90 (direction perpendicular to the thickness direction). The vertical axis indicates the relative position of each point of the workpiece 90 in the thickness direction of the workpiece 90. 10 indicates that the greater the variation of the vertical axis in FIG. 10, the greater the deformation of the workpiece 90 in the diagonal direction. In this experiment, the flow rate of air supplied to each suction chuck is adjusted in advance so that the suction force that each suction chuck acts on the workpiece 90 becomes equal. The suction force was set to a value necessary and sufficient to hold the workpiece in consideration of the acceleration generated during movement by the transfer robot and the weight of the workpiece. Thereby, the suction chuck 9 of the comparative example and the suction chuck 10 (type A and type B) of the present embodiment can be compared under the same conditions.

  As shown in FIG. 10, the workpiece 90 sucked and held by the suction chuck 9 of the comparative example is deformed by 0.08 mm or more, whereas the suction chuck 10 (type A and type B) of this embodiment is sucked and held. The deformation amount of the workpiece 90 is about 0.05 mm at the maximum. Thus, according to the suction chuck 10 of the present embodiment having three nozzle channels 44 for one air outlet 41, the deformation amount of the workpiece 90 can be reduced as compared with the suction chuck 9 of the comparative example. confirmed.

  As described above, the suction chuck 10 of the present embodiment includes the flat plate-like main body 11, the opposing surface 31, the plurality of air ejection ports 41, and the plurality of exhaust holes 42. A flow path for compressed air is formed inside the main body 11. The facing surface 31 is a surface on the side facing the workpiece 90 of the main body 11. The air outlet 41 opens in the opposing surface 31 in order to eject the compressed air supplied from the said flow path. The exhaust hole 42 is formed so as to open to the opposing surface 31 around the air ejection port 41 and to penetrate the main body 11 in the thickness direction. Each air outlet 41 is formed as a cylindrical space, and includes three nozzle channels 44 that open to the inside of the space, and each nozzle channel 44 is oriented along the inner wall of the cylindrical space. Compressed gas is ejected to

  In this way, by supplying compressed air from the three nozzle channels 44 into the air outlet 41, the flow of compressed air ejected from the air outlet 41 is dispersed in three directions. Since the flow of the compressed air is distributed in three directions, the influence of the position of the exhaust hole 42 on the flow of the compressed air is reduced. As a result, the exhaust holes 42 can be freely arranged and the degree of design freedom is improved. . Further, since the flow of compressed air is dispersed, the pressure distribution is made uniform, so that vibration and deformation of the workpiece 90 can be prevented. Moreover, since the flow rate of the compressed gas per nozzle channel 44 is reduced by increasing the number of nozzle channels 44, the impact received by the work due to the ejection of air can be reduced.

  In the suction chuck 10 of the present embodiment, the openings of the three nozzle channels 44 are formed at equal intervals in the circumferential direction of the air outlet 41.

  In this way, by supplying compressed air from the nozzle channels 44 that are opened at equal intervals into the air outlet 41, the compressed air ejected from the air outlet 41 can be uniformly dispersed in three directions.

  Further, in the suction chuck 10 of the present embodiment, the longitudinal direction of the nozzle channel 44 is formed in parallel to the facing surface 31.

  Thereby, the compressed air ejected from the air ejection port 41 can flow smoothly along the facing surface 31.

  Further, in the suction chuck 10 of the present embodiment, three exhaust holes 42 in the vicinity of the air ejection port 41 are formed on a concentric circle with the air ejection port 41 as the center.

  As a result, the compressed air that is dispersed and ejected from the air outlet 41 in three directions can be smoothly exhausted from the three exhaust holes 42.

  Further, in the suction chuck 10 of the present embodiment, the exhaust holes 42 nearest to the air ejection port 41 are formed at equal intervals on the concentric circles.

  Thereby, since compressed air can be uniformly disperse | distributed and it can flow to the exhaust hole 42, the pressure distribution around the air jet nozzle 41 can be equalized further.

  Further, in the suction chuck of this embodiment, the flow direction of the compressed air around the axis of the air jet 41 in the internal space of the arbitrary air jet 41 is formed in the vicinity of the air jet 41. The nozzle flow path 44 is formed so as to be in the opposite direction to the air jet port 41.

  Accordingly, it is possible to cancel the torque generated by the flow of air so as to turn in the air outlet 41 and prevent the work 90 sucked and held by the suction chuck 10 from rotating.

  In addition, the transfer robot 1 of the present embodiment includes the above-described suction chuck 10 and a parallel mechanism that can move the suction chuck 10 three-dimensionally within a predetermined range.

  That is, the workpiece 90 sucked and held by the suction chuck 10 can be freely moved three-dimensionally by the parallel mechanism. According to the suction chuck 10 of the present embodiment, since the thin flat work 90 can be sucked and held while suppressing vibration and deformation, the transfer robot 1 prevents deformation and breakage of the work 90. The workpiece 90 can be moved to an arbitrary position.

  The preferred embodiment of the present invention has been described above, but the above configuration can be modified as follows, for example.

  The suction chuck 10 can be mounted on the parallel mechanism type transfer robot 1 as described above, but is not limited thereto, and can be applied to, for example, a SCARA arm type transfer robot.

  In the above embodiment, the shape of the facing surface 31 of the suction chuck 10 is a rectangular shape, but the shape is not limited to this and may be an appropriate shape. However, if the shape of the opposing surface 31 of the suction chuck 10 is substantially congruent with the shape of the workpiece 90 to be handled and is configured to be slightly larger than the workpiece, the suction flow is uniformly applied to the workpiece 90 without waste. This is preferable.

  The number and arrangement of the air jets 41 formed on the facing surface 31 can also be changed as appropriate according to the weight and size of the workpiece 90.

  In the above embodiment, the compressed gas supplied to the jet outlet is air, but it goes without saying that other gas such as nitrogen may be supplied.

  In the above embodiment, the three exhaust holes 42 are arranged in the vicinity of one air outlet 41. However, the present invention is not limited to this. For example, as shown in FIG. Two exhaust holes 42 may be formed. In addition, the arrangement and number of the exhaust holes 42 can be freely changed. This is because the suction chuck 10 of the present invention has a unique effect that air can flow smoothly no matter how the exhaust holes 42 are arranged. However, in the suction chuck 10 of the present invention, since air is ejected from one air jet 41 in three directions, the configuration of the above embodiment in which three exhaust holes 42 are arranged in the vicinity of one air jet 41 is the air This is particularly suitable because it can flow the most smoothly and the air flow is not disturbed.

  The configuration for supplying air to each nozzle channel 44 (compressed air supply port 35, distribution channel 43, etc.) is not limited to the configuration of the above embodiment, and can be changed as appropriate. In short, it is only necessary that air can be blown from three directions into the internal space of one air jet port 41, and the detailed configuration thereof is not particularly limited.

1 Transfer robot (transfer equipment)
DESCRIPTION OF SYMBOLS 10 Suction chuck 11 Main body 31 Opposite surface 41 Air jet nozzle (jet nozzle)
42 Through hole 44 Nozzle flow path

Claims (7)

A suction chuck that sucks a thin flat workpiece and holds it in a non-contact state,
A flat plate-like body in which a compressed gas passage is formed;
A facing surface which is a surface of the main body facing the workpiece;
A plurality of jets opening in the facing surface for jetting compressed gas supplied from the flow path;
A plurality of exhaust holes formed so as to open in the opposing surface around the jet outlet and penetrate the main body in the thickness direction;
With
Each jet outlet is formed as a cylindrical space and includes three nozzle channels that open to the inside of the space, and each nozzle channel is compressed gas in a direction along the inner wall of the cylindrical space. A suction chuck characterized by ejecting water. The suction chuck according to claim 1,
The suction chuck, wherein the openings of the three nozzle channels are formed at equal intervals in a circumferential direction of the ejection port. The suction chuck according to claim 1 or 2,
The suction chuck according to claim 1, wherein a longitudinal direction of the nozzle channel is formed in parallel to the facing surface. The suction chuck according to any one of claims 1 to 3,
The suction chuck characterized in that at least three exhaust holes in the vicinity of the jet outlet are formed on a concentric circle with the jet outlet as a center. The suction chuck according to claim 4,
The suction chuck according to claim 1, wherein the exhaust holes nearest to the ejection port are formed at equal intervals on the concentric circle. The suction chuck according to any one of claims 1 to 5,
The nozzle flow path so that the flow direction of the compressed gas around the axis of the jet outlet in the inner space of any jet outlet is opposite to the other jet outlets formed in the vicinity of the jet outlet. Is formed. The suction chuck according to any one of claims 1 to 6,
A parallel mechanism capable of moving the suction chuck three-dimensionally within a predetermined range;
A transfer apparatus comprising: