JP2012233557A - Two-layer three-way valve for vibration isolation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable vibration isolation control and inclination control of a surface plate while utilizing characteristics of an automatic leveling valve in a two-layer three-way valve for a vibration isolation system.SOLUTION: A surface plate vibration isolation system 220 to which the two-layer three-way valve 78 for the vibration isolation system is applied includes air springs 22 and 23, individual driving devices 112 and 113, and a controller 110. The individual driving devices 112 and 113 include a control valve 40, link lever mechanisms 24 and 25, and an air supply source 32. The control valve 40 includes two-layer three-way valve 78 of a control sleeve 90, a fixed sleeve 91, and a spool part 80, a rotation/linear motion conversion mechanism 44 connected to the link lever mechanisms 24 and 25 to drive the control sleeve 90 and a spool actuator 120 to drive the spool part 80. The controller 110 has a function of controlling the operation of an air spring driving device 30 depending on the acceleration of a surface plate 224 to apply arbitrary displacement to the surface plate 224 with respect to a base 222 for the surface plate 224.

Description

  The present invention relates to a two-layer three-way valve for a vibration isolation system, and in particular, a two-layer three-way valve for a surface plate vibration isolation system that suppresses vibration of the surface plate by extending or contracting an air spring provided between the base and the surface plate. Regarding the valve.

  An anti-vibration table is used for precision measurement, precision processing, exposure equipment, and the like. The vibration isolator is designed so that vibration is not applied to the surface plate and vibration is reduced when measurement, processing, exposure, etc. are performed on the surface plate provided on the base. For this purpose, a vibration isolator that removes vibration between the base and the surface plate is used. For example, an air spring is provided between the base and the surface plate, and vibration transmission between the base and the surface plate is blocked by the air spring.

  For example, in Patent Document 1, an active vibration isolator is supported by a base installed on the floor and four air springs arranged on the top of the base so as to be movable in the vertical and horizontal directions. The structure provided with the surface plate for attaching the made vibration isolator is described. Here, an acceleration sensor is provided on the surface plate, and first and second giant magnetostrictive actuators that apply vertical and horizontal displacements to the surface plate are provided on the base.

  Further, Patent Document 2 describes a vibration isolating apparatus using an automatic level adjustment type air spring as a conventional technique. Here, the automatic level adjustment means detects the height position of the pedestal supported by the air spring and controls the air pressure supplied to the air spring so that the height position becomes a preset value. By doing so, the gantry is supported at a predetermined height position while being kept horizontal.

  By applying the automatic level adjustment type air spring to the vibration isolator, the supported body is supported in a horizontal position at a predetermined height, and further has a vibration isolating function. In this prior art anti-vibration device, if the stage moves or changes in load, the supported body that is supported by the anti-vibration device tilts, but there is a control delay in automatic level adjustment. It points out that the support of the body becomes unstable. Here, a stop valve is interposed in the pneumatic pressure supply circuit between the automatic level adjustment means and the air spring, and the support by the level adjustment function and the fixed stable support with the air spring sealed are selected by opening and closing the stop valve. It is disclosed that it can be done.

JP-A-11-257419 Japanese Patent Laid-Open No. 11-336839

  The automatic level adjusting means of Patent Document 2 is known as an automatic height adjusting valve using a link mechanism. By using this automatic height adjustment valve, the height of the surface plate can be automatically maintained at the reference height. Since the link mechanism used in the automatic height adjustment valve is a mechanical mechanism, it is more robust than electrical control. However, the automatic height adjustment valve can set the height position of the surface plate to the standard surface plate height position determined by the initial setting of the link mechanism shape, but can actively eliminate the vibration of the surface plate. In addition, the surface plate cannot be tilted.

  To remove the vibration of the surface plate, as described in Patent Document 1, the vibration of the surface plate is detected by an acceleration sensor or the like, and the height of the surface plate is displaced so that the acceleration becomes small. Alternatively, it is necessary to incline. In passive control that is not active control, it is impossible to perform vibration isolation and tilting of the surface plate according to acceleration. In Patent Document 1, a super magnetostrictive actuator is used to apply vertical and horizontal displacements to the surface plate, but the expansion and contraction of the air spring is not used like an automatic height adjustment valve.

  Thus, the active vibration isolation of the surface plate and the automatic height adjustment of the surface plate are used separately, and the configuration is complicated. An object of the present invention is to provide a two-layer three-way system for a surface plate vibration isolation system that enables vibration control and tilt control of the surface plate while utilizing the characteristics of the automatic height adjustment valve when used in a surface plate vibration isolation system. Is to provide a valve.

  The two-layer three-way valve for an anti-vibration system according to the present invention supplies or exhausts gas to an air spring disposed between the surface plate and the base to drive the air spring to extend and contract, thereby suppressing vibration of the surface plate and the surface plate. Is a three-way valve used for expansion and contraction drive of an air spring, and is connected to a spool part having a plurality of large-diameter lands connected to a small-diameter stem and a gas supply source. A fixed sleeve having an air supply port, an exhaust port, and a load port, and is slidably supported on the outer peripheral side and slidably supported on the inner peripheral side. A load port corresponding to the central land, and an air supply port and an exhaust port respectively provided corresponding to a space formed between the central land and the lands on both sides thereof, Relative within a specified range of movement In the predetermined movement range, the load port is in the range of the load port of the fixed sleeve, the supply port is in the range of the supply port of the fixed sleeve, and the exhaust port is in the range of the exhaust port of the fixed sleeve A sleeve, a spool actuator that is driven by displacing the spool portion relative to the control sleeve, and a spool sensor that detects displacement of the spool portion, and the sleeve portion has a two-layer structure of a fixed sleeve and a control sleeve. And the flow rate of the gas supplied from the load port to the air spring through the air supply port in the relative positional relationship between the center land of the spool portion and the load port of the control sleeve by the spool actuator being driven by the spool actuator Or the flow rate of gas discharged from the exhaust port via the load port from the air spring is determined

  With the above configuration, the two-layer three-way valve for the surface plate vibration isolation system is a spool-sleeve type three-way valve as an air spring driving device for a plurality of air springs arranged between the surface plate and the base, and the sleeve portion is It is a two-layer three-way valve having a two-layer structure of a fixed sleeve taking a fixed position and a control sleeve movable relative to the fixed sleeve. Then, when used in a surface plate vibration isolation system, the spool portion is driven to move in the axial direction with respect to the fixed sleeve of the two-layer three-way valve according to the drive signal, and the two layers according to the surface plate height position. The spool of the three-way valve is driven to move in the axial direction.

  In the three-way valve used in the conventional automatic height adjustment valve, the air spring is expanded and contracted only by driving the spool portion. However, in the above configuration, the control sleeve can be driven separately from the driving of the spool portion. With regard to the expansion and contraction control of the spring, it is possible to perform control to make an arbitrary surface plate height as well as control to make a predetermined surface plate height. As a result, it is possible to arbitrarily displace the surface plate so as to suppress the acceleration applied to the surface plate, or to incline the surface plate for vibration isolation, or to maintain the surface plate at a constant height.

  In order to arbitrarily change the height of the surface plate, the spool is moved in the axial direction with respect to the fixed sleeve and the control sleeve. By doing in this way, the value made into fixed surface plate height in the conventional automatic height adjustment valve can be offset, and surface plate height can be made into arbitrary height. In order to incline the surface plate, the respective spools are driven to move in the axial direction with respect to the fixed sleeve and the control sleeve corresponding to the plurality of air springs. By doing in this way, the height of the surface plate in which each air spring is provided can be varied arbitrarily, and the surface plate can be inclined. As described above, since the control of the three-way valve is made independent of the two systems, the surface plate can be arbitrarily displaced while taking full advantage of the characteristics of the automatic height adjustment valve.

  In the two-layer three-way valve for the surface plate vibration isolation system, the spool portion has a plurality of large-diameter lands connected to the small-diameter stem. The fixed sleeve has an air supply port connected to the gas supply source, an exhaust port, and a load port connected to the air spring. The control sleeve includes a load port corresponding to the central land of the plurality of lands of the spool, and an air supply port and an exhaust provided respectively corresponding to a space formed between the central land and the lands on both sides thereof. The fixed sleeve is movable relative to the fixed sleeve within a predetermined range of movement, wherein the load port is in the range of the load port of the fixed sleeve, and the air supply port is the air supply of the fixed sleeve In the range of the port, the exhaust port is set to be in the range of the exhaust port of the fixed sleeve.

  Therefore, the relative positional relationship between the center land of the spool portion and the load port of the control sleeve can be changed by the drive control of the spool portion or the drive control of the control sleeve. And by these drive controls, the gas flow rate supplied to the air spring from the load port via the air supply port is determined, or the gas flow rate discharged from the exhaust port via the load port from the air spring is determined.

It is a figure explaining the structure of the surface plate vibration isolating system in which the two-layer three-way valve of embodiment which concerns on this invention is used. It is a block diagram of the control valve to which the two-layer three-way valve of embodiment which concerns on this invention is applied. It is a detailed expanded sectional view of the two-layer three-way valve of an embodiment concerning the present invention. It is a detailed block diagram of the rotation / straight-ahead conversion mechanism in the surface plate vibration isolation system in which the two-layer three-way valve is used in the embodiment according to the present invention. It is a block diagram of the vibration isolator in which the two-layer three-way valve of the embodiment according to the present invention is used. In embodiment which concerns on this invention, it is a figure explaining a mode that an air spring is shrunk at the time of surface plate fixed height adjustment. In embodiment which concerns on this invention, it is a figure explaining a mode that an air spring is extended at the time of surface plate fixed height adjustment. In embodiment which concerns on this invention, it is a figure explaining a mode that an air spring is contracted when giving arbitrary displacement to a surface plate. In embodiment which concerns on this invention, it is a figure explaining a mode that an air spring is extended when arbitrary displacement is given to a surface plate.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In the following, it will be described how it is used in a surface plate vibration isolation system for the description of the two-layer three-way valve. The surface plate vibration isolation system described below is one example. For example, a spool-sleeve type control valve will be described as an example of a conventional automatic height adjustment valve, but this is only an example, and a load port that communicates with an air spring and a gas supply source. Other structures may be used as long as the gas control valve has three ports, that is, an air supply port and an exhaust port opened to the atmosphere side. Although a movable wire ring type force motor will be described as a spool actuator, other methods such as a plunger type actuator may be used. In some cases, a small motor such as a stepping motor or a servo motor and a linear motion mechanism such as a ball screw are used. It may be a combination.

  In the following description, it is assumed that pressurized air is supplied to the air spring, but the air here is not only the outside air but also a dry air or a gas in which the component ratio of nitrogen and oxygen is appropriately changed. The gas etc. which added the inert gas etc. may be sufficient.

  In the following description, the same elements are denoted by the same reference symbols in all the drawings, and redundant description is omitted. In the description in the text, the symbols described before are used as necessary.

  FIG. 1 is a diagram illustrating a configuration of a surface plate vibration isolation system 220 in which the two-layer three-way valve 78 is used. The surface plate vibration isolation system 220 includes a base 222 installed on the floor, a surface plate 224 for performing precision work such as precision measurement, precision processing, and fine exposure, and a space between the base 222 and the surface plate 224. The air springs 22 and 23 provided, the air spring driving device 30 for giving an arbitrary displacement to the surface plate 224 by the expansion and contraction of the air springs 22 and 23, the acceleration of the surface plate 224, and the air spring driving based on the displacement of the surface plate 224 A control device 110 that controls the operation of the device 30 is included.

  The base 222 is a base on which the surface plate 224 is mounted, and the air spring driving device 30, the control device 110, and the like are disposed therein. The surface plate 224 is a table having a flat surface and an appropriate mass. The air springs 22 and 23 are fluid springs that support the surface plate 224. The air springs 22 and 23 expand by introducing a pressurized gas into the internal space, and contract by releasing the pressurized gas to the outside. A plurality of air springs 22 and 23 are provided on the bottom surface of the surface plate 224. Since FIG. 1 is a front view, two air springs 22 and 23 are shown, but the entire surface plate 224 has four locations, that is, four air springs. However, the number can be increased or decreased according to the size of the surface plate 224. For example, the surface plate 224 may be supported at three points using three air springs. Five can be supported at five points, or more.

  The air spring driving device 30 includes a plurality of individual driving devices 112 and 113 corresponding to the number of air springs 22 and 23, and the operation thereof is controlled by the control device 110 as a whole. The individual driving devices 112 and 113 include a control valve 40, link lever mechanisms 24 and 25, and a gas supply source 32. The air springs 22 and 23 and the individual driving devices 112 and 113 correspond one-to-one, and the configuration of each pair is the same. Therefore, in the following, the individual driving device 112 is represented by its control valve 40, link lever. The description of the mechanism 24 will be continued.

  The control valve 40 includes a control sleeve 90, a fixed sleeve 91, a two-layer three-way valve 78 of a spool portion 80, a rotation / straight-forward conversion mechanism 44 that is connected to the link lever mechanisms 24 and 25 and drives the control sleeve 90, and a spool portion. A spool actuator 120 that drives 80 is included.

  The control device 110 has a function of controlling the operation of the air spring driving device 30 to give the surface plate 224 an arbitrary displacement with respect to the base 222 with respect to the base 222. Specifically, the control device 110 receives the feedback of the acceleration of the surface plate 224 by the acceleration sensor 111, and returns the feedback of the surface plate height that is the displacement of the surface plate 224 from the displacement of the control sleeve 90 of the two-layer three-way valve 78. Receiving the feedback of the displacement of the spool portion 80 of the two-layer three-way valve 78, processing the feedback information, removing the vibration of the surface plate 224, maintaining the surface plate 224 at a constant height, or the surface plate 224. Control to tilt the.

  2 is a structural view of the entire control valve 40, FIG. 3 is a detailed view of a portion of the two-layer three-way valve 78, and FIG. 4 is a detailed view of the rotation / straight-forward conversion mechanism 44. In these figures, orthogonal XYZ axes are shown. The X direction is the moving direction of the spool unit 80 and the control sleeve 90.

  The control valve 40 has three gas flow ports, an air supply port connection portion 53, an exhaust port opening portion 55, and a load port connection portion 57, and two signal connection portions, a spool drive control port 128 and a spool sensor port 146. These are attached to the housing of the control valve 40. The housing of the control valve 40 is assembled by connecting the housings of the respective components because the control valve 40 combines a plurality of components. Here, the housing of the two-layer three-way valve 78 is used. The fixed sleeve 91, which is a body, is representatively referred to as a casing of the control valve 40.

  The air supply port connection portion 53 is a connection port for connecting to the air supply port 52 of the two-layer three-way valve 78 and supplying pressurized air from the gas supply source 32. The exhaust port opening 55 is an open end that is connected to the exhaust port 54 of the two-layer three-way valve 78 and opens to the atmosphere. The load port connection part 57 is a connection port for connecting the load port 56 of the two-layer three-way valve 78 and the air spring 22. An appropriate filter may be provided in the air supply port connection portion 53 and the load port connection portion 57. Further, an appropriate silencer may be provided in the exhaust port opening 55.

  The spool drive control port 128 is a connector portion for connecting a signal line for transmitting a drive control signal from the control device 110 to the spool actuator 120. The spool sensor port 146 is a connector for connecting a signal line for transmitting an output signal of a displacement sensor, which is a spool sensor 140 that detects the state of the spool unit 80, to the control device 110.

  The two-layer three-way valve 78 is a kind of three-way valve having an air supply port 52, an exhaust port 54, and a load port 56, and has a spool-sleeve mechanism. Here, the sleeve is divided into two layers, and the control sleeve 90 And a fixing sleeve 91. The fixed sleeve 91 is a casing of a spool / sleeve mechanism and corresponds to a sleeve of a general spool / sleeve mechanism. The control sleeve 90 is a member that is slidably supported on the fixed sleeve 91 on the outer peripheral side, and that slidably supports the spool portion 80 on the inner peripheral side. The detailed structure of the two-layer three-way valve 78 will be described later.

  The spool shaft 118 is a portion in which the spool portion 80 extends and protrudes in the −X direction from the region of the two-layer three-way valve 78. The spool actuator 120 attached to the spool shaft 118 is a movable linear ring type force motor that moves and drives the spool portion 80 in the axial direction. A displacement sensor, which is a spool sensor 140 attached to the tip of the spool shaft 118, is composed of a magnetic body shaft 142 and a differential transformer 144, and has a function of detecting the axial displacement of the spool portion 80.

  The spool actuator 120 is attached to the spool shaft 118 and has a drive arm 122 whose tip is opened in a cup shape, a coil 124 provided at the tip of the drive arm 122, and a coil 124 attached to the casing of the control valve 40 and facing the coil 124. The permanent magnet 126 is arranged to be arranged. A drive current signal is supplied to the coil 124 from the control device 110 via the spool drive control port 128. A driving force in the axial direction is applied to the driving arm 122 by the cooperative action of the current flowing in the coil 124 by this driving current signal and the magnetic flux of the permanent magnet 126, thereby driving the spool portion 80 to move in the axial direction. can do. As shown in FIG. 2, a neutral spring that pulls the spool actuator 120 back to the neutral position may be provided between the drive arm 122 and the fixed sleeve 91 that is the housing.

  The spool sensor 140 is a displacement sensor that detects the amount of movement of the spool unit 80 in the X direction. In FIG. 2, a differential transformer type is illustrated as the spool sensor 140, but a displacement sensor of a type other than the differential transformer type may be used. For example, an optical displacement sensor, a capacitance displacement sensor, or the like can be used.

  Next, the configuration of the two-layer three-way valve 78 will be described with reference to FIG. FIG. 3 is a cross-sectional view showing details regarding the two-layer three-way valve 78, and shows the state when the two-layer three-way valve 78 is in a neutral state. The two-layer three-way valve 78 includes the fixed sleeve 91, the control sleeve 90, and the spool portion 80 as described above. The supply port 52, the exhaust port 54, and the load port 56 as the two-layer three-way valve 78 are provided in the fixed sleeve 91.

  The control sleeve 90 is a cylindrical member that is slidably supported by the fixed sleeve 91 on the outer peripheral side and slidably supports the spool portion 80 on the inner peripheral side. The control sleeve 90 is provided with an air supply port 62, an exhaust port 64, and a load port 66 corresponding to the air supply port 52, the exhaust port 54, and the load port 56 of the fixed sleeve 91, respectively.

  As shown in FIG. 3, the opening size of the air supply port 62 is larger than the opening size of the air supply port 52, the opening size of the exhaust port 64 is larger than the opening size of the exhaust port 54, and The opening size is set larger than the opening size of the load port 56. As a result, when the control sleeve 90 moves relative to the fixed sleeve 91 within a predetermined predetermined movement range, the opening of the air supply port 62 is in the predetermined movement range. The opening of the exhaust port 64 is in the range of the opening of the exhaust port 54 of the fixed sleeve 91, and the opening of the load port 66 is in the range of the opening of the load port 56 of the fixed sleeve 91. is there. That is, even if the control sleeve 90 moves relative to the fixed sleeve 91, the air supply port 62 always communicates with the air supply port 52, the exhaust port 64 always communicates with the exhaust port 54, and the load port 66 It always communicates with the load port 56.

  The spool portion 80 of the two-layer three-way valve 78 is a shaft member having a thin-shaft stem portion 81, a central land 86 having a larger outer diameter than the stem portion 81, and front and rear lands 82 and 84 disposed on both sides thereof. is there.

  Next, the link lever mechanism 24 will be described. The link lever mechanism 24 has a function of detecting a height position indicating the displacement of the surface plate 224 with respect to the base 222. The link lever mechanism 24 includes a surface plate side arm whose one end is supported so as to be rotatable with respect to the surface plate 224, a lever which is a base side arm whose other end is supported so as to be rotatable relative to the base 222, and a surface plate. This is a mechanism in which the other end of the side arm and the one end of the base side arm are rotatably connected to each other. When the height position of the surface plate 224 with respect to the base 222 changes, the link shape of the link lever mechanism 24 changes, and the shape change is uniquely determined by the height of the surface plate 224 with respect to the base 222. Therefore, for example, a predetermined inclination angle of the base side arm with respect to the reference surface of the base 222 can be used as a height corresponding value corresponding to the height of the surface plate 224 with respect to the base 222.

  The change in the shape of the link lever mechanism 24 indicates the value corresponding to the height of the surface plate 224 relative to the base 222, that is, the amount of displacement of the surface plate 224 relative to the base 222. The displacement amount of the surface plate 224 is transmitted to the rotation / straight-ahead conversion mechanism 44 of the control valve 40 and is used for driving control of the control sleeve 90. Further, the signal is converted into an electric signal by a resolver 132 provided in the rotation / straight-axis conversion mechanism 44 and transmitted to the control device 110 as feedback of the displacement amount.

  The rotation / linear conversion mechanism 44 will be described with reference to FIG. The rotation / linear advance conversion mechanism 44 is provided at the end of the control sleeve 90 in the −X direction, and is connected to the link lever mechanism 24. In FIG. 4, the link lever mechanism 24 includes a surface plate side arm 26, a lever 28 that is a base side arm, and a rotation connecting portion 27 that connects these to each other in a freely rotatable manner.

  The rotation / straight-ahead conversion mechanism 44 changes the shape formed by the surface plate side arm 26 and the base side arm lever 28 according to the surface plate height value that is the height of the surface plate 224 with respect to the base 222. A function of converting the accompanying rotational movement of the lever 28 into a straight movement of the control sleeve 90 is provided. Accordingly, the control sleeve 90 is driven to move in the axial direction according to the surface plate height value. In that sense, the link lever mechanism 24 and the rotation / linear advance conversion mechanism 44 correspond to a sleeve actuator that moves and drives the control sleeve 90.

  The rotation / straight-ahead conversion mechanism 44 includes a case 160 fixed to the casing of the control valve 40, a rotating body 162 rotatably supported by the case 160, a disk 130 that rotates integrally with the rotating body 162, An eccentric pin 164 arranged eccentric from the rotation center axis of the disc 130 and a guide groove 168 provided in the guide plate 166 connected to the −X direction end of the control sleeve 90 are configured.

  Here, one end of the lever 28 is attached to the central axis 161 of the rotating body 162. The center axis 161 of the rotating body and the center axis of rotation of the disc 130 are concentric. Further, since the guide plate 166 is integral with the control sleeve 90, the guide plate 166 can move only in the X direction. The guide groove 168 is a groove provided along the Z direction and has a groove width for receiving the eccentric pin 164.

  The operation of the rotation / straight-ahead conversion mechanism 44 will be described. As described above, when the height position of the surface plate 224 with respect to the base 222 changes, the link shape of the link lever mechanism 24 changes. In response to the change in the link shape, the lever 28 serving as the base side arm rotates the central axis 161 of the rotating body 162. This rotates around. As a result, the eccentric pin 164 rotates around the central axis 161. The rotation of the eccentric pin 164 moves the guide plate 166 in the X direction by restraint of the guide groove 168. Since the guide plate 166 and the control sleeve 90 are integrated, when the height position of the surface plate 224 with respect to the base 222 is changed, the control sleeve 90 is driven to move in the X direction according to the change.

  A resolver 132 that detects the rotation angle of the central axis 161 of the rotating body 162 is provided inside the case 160. Thus, the surface plate height position, which is the amount of displacement of the surface plate 224, is detected by the resolver 132 via the shape change of the link lever mechanism 24. The detection signal of the resolver 132 is transmitted to the control device 110 through an appropriate signal line. Instead of the resolver 132, another type of rotation angle detector may be used. For example, an encoder, a potentiometer, or the like can be used.

  FIG. 5 is a block diagram of the surface plate vibration isolation system 220 configured as described above. The control device 110 has two control processing functions: a vibration isolation processing unit 230 and a tilt processing unit 232. The vibration isolation processing unit 230 has a function of acquiring the acceleration of the surface plate 224 by the acceleration sensor 111 and displacing the surface plate 224 so as to cancel the acceleration. The inclination processing unit 232 has a function of displacing the surface plate 224 with respect to the base 222 by displacing the air springs 22 and 23 with different displacement amounts. The surface plate 224 may be tilted depending on the acceleration applied to the surface plate 224 as in the case where a non-uniform load is applied to the surface plate 224, but the inclination processing unit 232 accelerates the surface plate 224 to tilt. It is possible to perform control processing for canceling and returning the surface plate 224 to a horizontal position.

  The control process of the vibration isolation processing unit 230 is performed as follows. When the surface plate 224 receives vibration, the acceleration sensor 111 detects the vibration, and the control device 110 acquires it. Based on the mass of the surface plate 224, the spring constant of the air spring 22, the damping characteristics, etc., the control device 110 calculates a displacement amount corresponding to a reaction force that cancels the acceleration of the surface plate 224, and uses the displacement amount as a displacement command. The value is given to the spool actuator 120 of the two-layer three-way valve 78. The spool actuator 120 drives the spool unit 80 to move in the axial direction according to the displacement command value. On the other hand, the control sleeve 90 receives displacement driving via the link lever mechanism 24 and the rotation / straight-ahead conversion mechanism 44 in accordance with the surface plate height position which is the displacement amount of the surface plate 224. The two-layer three-way valve 78 supplies a pressurized gas to the air spring 22 or releases the gas in the air spring 22 to the atmosphere according to the displacement amount difference between the spool portion 80 and the control sleeve 90. . As a result, the air spring 22 expands and contracts to displace the surface plate 224.

  As described above, the control device 110 performs control for reducing the acceleration of the base plate 224 with respect to the base 222 according to the acceleration of the base plate 224. The actual displacement of the surface plate 224 performed for vibration isolation is returned to the control device 110 by the height feedback loop 234 via the resolver 132, and the actual acceleration of the surface plate 224 subjected to vibration isolation is The acceleration feedback loop 236 returns to the control device 110 via the acceleration sensor 111. The actual amount of displacement of the spool unit 80 performed for vibration isolation is also returned to the control device 110 by the spool unit feedback loop 238 via the spool sensor 140. The control device 110 obtains a deviation between the target value and the command value by these feedbacks, performs control to reduce the deviation, and removes the vibration of the surface plate 224.

  The control process of the inclination process part 232 is performed as follows. Now, assuming that the surface plate 224 is inclined due to an offset load or the like, the height position of the surface plate 224 corresponding to the plurality of air springs 22 and 23 corresponds to the link lever mechanism 24, the rotation / straight-ahead conversion mechanism 44, and the resolver 132. Is transmitted to the control device 110 via When the control device 110 receives information on the height position of the surface plate 224 at locations corresponding to the plurality of air springs 22 and 23, the control device 110 changes the height to be changed so that the height becomes a desired target height. Use command value. Then, the displacement command value is given to the spool actuator 120 of the two-layer three-way valve 78. The spool actuator 120 drives the spool unit 80 to move in the axial direction according to the displacement command value. On the other hand, the control sleeve 90 receives displacement driving via the link lever mechanism 24 and the rotation / straight-ahead conversion mechanism 44 in accordance with the surface plate height position which is the displacement amount of the surface plate 224. The two-layer three-way valve 78 supplies a pressurized gas to the air spring 22 or releases the gas in the air spring 22 to the atmosphere according to the displacement amount difference between the spool portion 80 and the control sleeve 90. . As a result, the air spring 22 expands and contracts to displace the surface plate 224.

  As described above, the control device 110 drives the air springs 22 and 23 according to the height positions of the respective portions of the surface plate 224 to perform the inclination displacement control so as to cancel the inclination of the surface plate 224. Then, the actual displacement amount of each part of the surface plate 224 performed for the tilt process is returned to the control device 110 by the height feedback loop 234 via each resolver 132, and the actual acceleration of the surface plate 224 is It is returned to the control device 110 via the acceleration sensor 111. Note that the actual displacement of the spool unit 80 performed for the tilting process is also returned to the control device 110 through the spool sensor 140 in the spool unit feedback loop. The control device 110 obtains a deviation between the target value and the command value by these feedbacks, performs control to reduce the deviation, and tilts the surface plate 224 so as to cancel the inclination of the surface plate 224.

  During normal operation, control device 110 provides spool actuator 120 with a displacement command value of zero, that is, a command value for maintaining the height position of surface plate 224 at the standard surface plate height position with respect to base 222. At this time, the axial position of the spool portion 80 is a fixed position with respect to the base 222. If the platen 224 has a height different from the standard platen height position due to some reason, the two-layer three-way valve 78 will move against the air spring 22 in accordance with the displacement amount difference between the spool portion 80 and the control sleeve 90. Then, pressurized gas is supplied or the gas in the air spring 22 is released to the atmosphere. As a result, the air spring 22 expands and contracts to displace the surface plate 224. As a result, the surface plate 224 is displaced in a direction to return to the direction of the original standard surface plate height position. When the platen 224 is completely returned to the original standard platen height position, the two-layer three-way valve 78 closes the communication with the air spring 22, so that the original standard platen height position is maintained. This function is the same as the automatic level adjustment of the surface plate 224 using an air spring in the prior art.

  The operation of the above configuration will be described with reference to FIGS. These figures correspond to FIG. 3 and FIG. 3 shows a neutral state. On the other hand, FIGS. 6 and 7 show the case where the spool 80 does not move and the control sleeve 90 moves. FIGS. 8 and 9 are diagrams showing a case where the control sleeve 90 does not move and the spool portion 80 moves. 6 and 7 correspond to the control for maintaining the surface plate 224 at a predetermined standard surface plate height position, and FIGS. 8 and 9 correspond to the control for displacing the surface plate 224 to an arbitrary height. A typical example of the former is level adjustment control that adjusts the surface plate height to be constant, and a typical example of the latter is tilt control that tilts the surface plate 224. Therefore, the description will be continued below by referring to FIGS. 6 and 7 as level adjustment control and FIGS. 8 and 9 as inclination control. As an actual action, the control sleeve 90 and the spool part 80 may move, but even at that time, the action can be broken down into the action of the control sleeve 90 and the action of the spool 80.

6 and 7 are diagrams for explaining level adjustment control that has been well known in the past. FIG. 6 shows a case where the actual surface plate height value h is higher than the standard surface plate height value h ₀ in the level adjustment control. This case corresponds to a case where the control sleeve 90 is moved in the −X direction with respect to the spool portion 80 in the neutral position by the link lever mechanism 24 and the rotation / straight-ahead conversion mechanism 44. Here, since the load port 66 of the control sleeve 90 moves in the −X direction with respect to the central land 86 of the spool portion 80, the load port 66 is opened. As a result, the load port 56 is opened to the atmosphere via the exhaust port opening 55 in the space-exhaust port 64 -exhaust port 54 path between the load port 66 -the central land 86 and the adjacent land 84. .

Thus, the air spring 22 and the exhaust port opening 55 communicate with each other, whereby air from the air spring 22 is released to the atmosphere, and the air spring 22 is reduced. When the air spring 22 shrinks, the surface plate height value h decreases. When the surface plate height value h decreases, the control sleeve 90 is returned to the spool portion 80 in the + X direction. When the surface plate height value h reaches the standard surface plate height value h ₀ , the positions of the central land 86 of the spool portion 80 and the load port 66 coincide. Thereby, it returns to the neutral state of FIG. 3, and the discharge | release of the air from the air spring 22 stops. In this way, level adjustment control for automatically returning the actual surface plate height value to the standard surface plate height value h ₀ is automatically performed.

FIG. 7 shows a case where the actual surface plate height value h is lower than the standard surface plate height value h ₀ in the level adjustment control. This case corresponds to the case where the control sleeve 90 is moved in the + X direction with respect to the spool portion 80 in the neutral position by the link lever mechanism 24 and the rotation / straight-ahead conversion mechanism 44. Here, since the load port 66 of the control sleeve 90 moves in the + X direction with respect to the central land 86 of the spool portion 80, the load port 66 is opened. As a result, the load port 56 is a gas supply via the air supply port connection portion 53 in the space-air supply port 62-air supply port 52 path between the load port 66-the central land 86 and the adjacent land 82. In communication with the source 32.

In this manner, the air supply port connection portion 53 and the air spring 22 communicate with each other, whereby pressurized air is supplied to the air spring 22 and the air spring 22 extends. When the air spring 22 extends, the platen height value h increases. When the surface plate height value h increases, the control sleeve 90 is returned to the −X direction with respect to the spool portion 80. When the surface plate height value h reaches the standard surface plate height value h ₀ , the positions of the center land 86 of the spool portion 80 and the load port 66 of the control sleeve 90 coincide. Thereby, it returns to the neutral state demonstrated in FIG. 3, and the supply of the pressurized air from the air supply port connection part 53 stops. In this way, level adjustment control for automatically returning the actual surface plate height value to the standard surface plate height value h ₀ is automatically performed.

  Next, the tilt control will be described. In the following description, it is assumed that the surface plate height value, which is the height between the surface plate 224 and the base 222, is in the standard state and the control sleeve 90 is in the neutral state before the tilt control is started.

  FIG. 8 shows a case where the platen height value is set low in the tilt control. This case corresponds to a case where the spool actuator 80 is moved in the + X direction by the spool actuator 120 with respect to the control sleeve 90 in the neutral position. Here, since the central land 86 of the spool portion 80 moves in the + X direction with respect to the load port 66 of the control sleeve 90, the load port 66 opens. As a result, the load port 56 is opened to the atmosphere via the exhaust port opening 55 in the space-exhaust port 64 -exhaust port 54 path between the load port 66 -the central land 86 and the adjacent land 84. .

Thus, the air spring 22 and the exhaust port opening 55 communicate with each other, whereby air from the air spring 22 is released to the atmosphere, and the air spring 22 is reduced. When the air spring 22 shrinks, the surface plate height value h decreases. When the surface plate height value h decreases, the spool portion 80 is returned to the control sleeve 90 in the −X direction. When the surface plate height value h reaches the set surface plate height value h ₁ arbitrarily set by the displacement command value, the positions of the central land 86 of the spool portion 80 and the load port 66 coincide. Thereby, it returns to the neutral state of FIG. 3, and the discharge | release of the air from the air spring 22 stops. In this manner, the surface plate inclination control is automatically performed so that the actual surface plate height value is set to an arbitrary set surface plate height value h ₁ .

  FIG. 9 shows a case where the platen height value is set high in the tilt control. This case corresponds to the case where the spool actuator 80 is moved in the −X direction with respect to the control sleeve 90 in the neutral position by the spool actuator 120. Here, since the central land 86 of the spool portion 80 moves in the −X direction with respect to the load port 66 of the control sleeve 90, the load port 66 is opened. As a result, the load port 56 is a gas supply via the air supply port connection portion 53 in the space-air supply port 62-air supply port 52 path between the load port 66-the central land 86 and the adjacent land 82. In communication with the source 32.

In this manner, the air supply port connection portion 53 and the air spring 22 communicate with each other, whereby pressurized air is supplied to the air spring 22 and the air spring 22 extends. When the air spring 22 extends, the platen height value h increases. When the surface plate height value h increases, the spool portion 80 is returned to the + X direction with respect to the control sleeve 90. When the surface plate height value h reaches the set surface plate height value h ₂ arbitrarily set by the displacement command value, the positions of the center land 86 of the spool portion 80 and the load port 66 of the control sleeve 90 coincide. Thereby, it returns to the neutral state demonstrated in FIG. 3, and the supply of the pressurized air from the air supply port connection part 53 stops. In this way, the platen tilt control for the actual plate height value in any setting plate height values h ₂ is performed automatically.

  In the above description, it is assumed that the movement of the control sleeve 90 is performed by the link lever mechanism 24 whose shape changes according to the height of the surface plate, and the movement of the spool portion 80 is performed by the spool actuator 120. The setting surface plate height value can be changed by setting an offset of the relative position between the spool portion 80 and the control sleeve 90. Therefore, the movement of the spool portion 80 may be performed by the link lever mechanism 24 whose shape changes depending on the height value of the surface plate, and the movement of the control sleeve 90 may be performed by a control sleeve actuator such as a force motor.

  In the above description, the individual driving devices 112 and 113 are built in the base 222. Of course, the individual driving devices 112 and 113 may be built in the surface plate 224.

  The two-layer three-way valve for vibration isolation system according to the present invention can be used for a precision vibration isolation table held by an air spring.

  22, 23 Air spring, 24, 25 Link lever mechanism, 26 Surface plate side arm, 27 Rotation connection part, 28 Lever, 30 Air spring drive device, 32 Gas supply source, 40 Control valve, 44 Rotation / straight-ahead conversion mechanism, 52 Supply port, 53 Supply port connection, 54 Exhaust port, 55 Exhaust port opening, 56 Load port, 57 Load port connection, 62 Supply port, 64 Exhaust port, 66 Load port, 78 Two-layer three-way valve, 80 spool portion, 81 stem portion, 82, 84 front and rear lands, 86 central land, 90 control sleeve, 91 fixed sleeve, 110 control device, 111 acceleration sensor, 112, 113 individual drive device, 118 spool shaft, 120 spool actuator, 122 Drive arm, 124 coil, 126 permanent magnet, 128 spool drive control port, 13 Disc, 132 Resolver, 140 Spool sensor, 142 Magnetic shaft, 144 Differential transformer, 146 Spool sensor port, 160 Case, 161 Central shaft, 162 Rotating body, 164 Eccentric pin, 166 Guide plate, 168 Guide groove, 220 Constant Panel vibration isolation system, 222 base, 224 surface plate, 230 vibration isolation processing section, 232 tilt processing section, 234 height feedback loop, 236 acceleration feedback loop, 238 spool section feedback loop.

Claims (1)

In a surface plate vibration isolation system that suppresses vibration of the surface plate and tilts the surface plate by supplying or exhausting gas to the air spring arranged between the surface plate and the base and driving the air spring to extend and contract, A three-way valve used for telescopic drive,
A spool portion having a plurality of large-diameter lands connected to a small-diameter stem;
A fixed sleeve having an air supply port connected to a gas supply source, an exhaust port, and a load port;
A load port corresponding to a center land of a plurality of lands of the spool, a load port corresponding to the center land of the plurality of lands of the spool, a center land and lands on both sides thereof Each having a supply port and an exhaust port provided corresponding to a space formed between the fixed sleeve and the fixed sleeve. Is in the range of the load port of the fixed sleeve, the supply port is in the range of the supply port of the fixed sleeve, the exhaust port is in the range of the exhaust port of the fixed sleeve, and
A spool actuator that is driven by displacing the spool portion relative to the control sleeve;
A spool sensor for detecting the displacement of the spool portion;
The sleeve portion has a two-layer structure of a fixed sleeve and a control sleeve, and the spool portion is driven by a spool actuator, so that the relative positional relationship between the center land of the spool portion and the load port of the control sleeve A two-layer three-way valve for a vibration isolation system in which the gas flow rate supplied to the air spring from the load port through the air supply port is determined or the gas flow rate discharged from the exhaust port through the load port from the air spring is determined .

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