JP5325062B2 - Control valve drive mechanism - Google Patents

Description

  The present invention relates to a control valve such as a leveling valve that supplies and discharges gas to and from the gas spring so as to maintain a constant height of a supported body supported by the gas spring, for example, and drives the same. Related to the mechanical structure.

  2. Description of the Related Art Conventionally, there has been known a vibration isolation table in which a precision device that dislikes vibration, such as an optical device, is installed on a surface plate and elastically supported by a plurality of air springs. Adjustment (leveling adjustment) for keeping the surface plate horizontal and maintaining the height constant is performed by supplying and discharging pressurized air to and from each air spring. That is, as disclosed in Patent Documents 1 and 2 as an example, each air spring has a mechanical leveling valve so as to switch between air supply and exhaust according to the height of the surface plate supported by the air spring. It is attached.

  For example, in the case of Patent Document 1, as shown in FIG. 1 of the same document, the upper portion of the piston 19 protrudes from the upper end of the cylindrical valve body 7, and the bracket 22 provided in the vicinity thereof is provided with a support shaft 23. The base end of the lever 24 is rotatably supported. Further, the lower end of the operating pin 25 fixed in the middle of the lever 24 contacts the upper end surface of the piston 19, while the upper end of the contact rod 26 (see FIG. 5 of the same document) fixed to the tip of the lever 24 is It is in contact with the lower surface of the vibration isolation table.

  Then, for example, when the load of one of the air springs 2 increases with the operation of the device and the supporting height decreases, the lever 24 rotates downward and the piston 19 is pushed down. The on-off valve 16) moves and the pressurized air is supplied to the pressure vessel 3. On the contrary, if the support height is increased, the lever 24 is lifted, and air is discharged from the pressure vessel 3 of the air spring 2. Thus, by repeating supply and discharge of air, the support height of the surface plate by the air spring is kept constant.

No. 8-7157 Utility Model Registration No. 3116309

  By the way, in recent years, a device equipped with a stage with movement of a heavy workpiece has also been installed on the vibration isolation table, and in response to the change in the shared load of the air spring becoming severe, There is a tendency that the operation frequency increases and the operation amount of the piston also increases. In order to quickly supply and discharge air in response to such large load fluctuations, the operating amount of the piston must be increased.

  However, when the operation amount of the piston is increased in this way, for example, as shown in FIGS. 2 to 4 of Patent Document 1, the rotation angle of the lever member 24 is increased, and the operation pin 25 is connected to the upper end surface of the piston 19. Therefore, the frictional resistance is inevitably increased.

Further, the sliding of the operating pin 25 causes the upper end surface of the piston 19 to wear, and when the wear powder bites in, the frictional resistance increases rapidly, and the smooth operation of the piston 19 is prevented.
If wear progresses due to long-term use, the lower end of the operating pin 25 may be caught by the upper end surface of the piston 19, which may cause malfunction.

  The present invention has been made paying attention to such a new problem. The purpose of the present invention is to devise a drive mechanism for a control valve that supplies and discharges a gas, such as a leveling valve, and to swing the lever member. It is to reduce the frictional resistance with the piston end surface accompanying the movement) and realize a smooth operation over a long period of time.

  In order to achieve the above object, in the present invention, a spherical body is provided at a portion where the lever member and the end of the piston abut so as to be able to roll in any direction via a spherical bearing or the like.

  Specifically, in the first aspect of the present invention, the gas spring connected to the gas spring that receives the load of the supported body, supplies and discharges the gas, the air supply port that supplies the gas from the pressure source, and the gas spring. And a control valve drive mechanism having an exhaust port for exhausting the gas discharged from the exhaust gas. The control valve is configured to move the valve body accommodated in the housing by moving the valve body. It is assumed that the position can be switched between an air supply position that communicates with the exhaust port, an exhaust position that communicates with the air supply / exhaust port and the exhaust port, and a neutral position that does not supply and exhaust gas between the two positions.

In the drive mechanism, the base end portion is rotatably supported by the housing of the control valve, while the distal end portion receives the load of the supported body and rotates in the moving direction of the valve body. A lever member is provided, and the control valve is provided with a piston that is movable in the vertical direction in conjunction with the valve body. The upper end surface of the piston is located near the base end side of the lever member. And a spherical body that can roll in any direction .

  When the load from the supported body is increased and the gas spring is compressed due to the above configuration, or when the load is decreased and the gas spring is expanded, the lever member is moved around the base end accordingly. It rotates and the piston is actuated as before. Then, the valve body is moved by the operation of the piston, and the gas is supplied to and discharged from the gas spring.

In this way, at the part closer to the base end side of the lever member that rotates, it contacts the upper end surface of the piston that moves in the vertical direction in conjunction with the valve body, and supports a spherical body that can roll in any direction. and which, since this becomes to roll while sliding against the piston, the frictional resistance is realized decrease significantly smooth operation in conventional models. In addition, wear due to sliding is greatly reduced, and even if there is wear powder, rolling of the spherical body may not be hindered, and there is no fear of malfunction even when used for a long period of time.

Preferably, before Symbol spheroids is that which is supported on the lever member via a spherical bearing (Claim 2), In this way, it is not necessary to perform machining or the like to the piston of the control valve. As the lever member rotates, the spherical body rolls while sliding on the end face of the piston. At this time, the larger the spherical body, the more advantageous it is to reduce the frictional resistance. The larger the spherical body, the smaller the surface pressure with the piston end surface. This is also preferable for reducing frictional resistance and wear.

  More preferably, as the spherical bearing, a spherical ball bearing in which a plurality of balls are movably interposed between a spherical body and a spherical load receiving surface supporting the outer periphery thereof is used. By doing so, the frictional resistance can be made as small as possible (claim 3).

In addition, it is preferable that the height of the spherical body that abuts the upper end surface of the piston in the neutral position between the lower end and the upper end when the valve body and the piston move in the vertical direction as in a leveling valve. It is set so that the rotation center height of the base end part of the lever member is included, that is, both heights are substantially the same (claim 4). If it carries out like this, the sliding amount on the piston end surface of the spherical body accompanying rotation of a lever member will become small geometrically, and it will become advantageous to reduction of frictional resistance and wear.

  In other words, when the control valve is in the neutral position, if the center of the spherical body provided on the lever member and the center of rotation of the base end thereof are substantially at the same height, the lever member rotates up and down from there. This is because when the center of the spherical body moves up and down, the amount of displacement in the horizontal direction relative to the magnitude of the vertical movement, that is, the amount of sliding on the piston end surface of the spherical body becomes small (see FIG. 4). reference). Particularly preferred in this sense is that the heights of both coincide.

  Furthermore, it is preferable that the rotation center of the base end portion of the lever member is positioned outward from the outer periphery of the end surface of the housing of the control valve. This means that the distance from the center of rotation of the lever member to the spherical body is relatively large, and if the operation amount of the piston by the spherical body is the same, the vertical rotation angle of the lever member is relatively small. Thus, the sliding amount of the spherical body on the piston end surface is reduced accordingly. Further, in the case of a leveling valve, there is an advantage that it is possible to prevent the abrasion powder generated from the shaft support portion of the lever member from adhering to the piston.

  As described above, according to the control valve drive mechanism according to the present invention, for example, in a control valve that supplies and discharges gas, such as a leveling valve, a lever member that rotates by receiving a load from a supported body and an end portion of a piston Since the spherical body is provided so as to be rotatable in any direction by the spherical bearing, the frictional resistance with the piston end face due to the rotation of the lever member is greatly reduced, and it is operated smoothly over a long period of time. be able to.

  In the case of a leveling valve, the height of the spherical body that is in contact with the upper end surface of the piston in its neutral position is set to be approximately the same as the height of the rotation center of the base end portion of the lever member. The sliding amount on the upper end surface can be reduced, which is advantageous in reducing frictional resistance and wear.

It is a front view of the air spring and leveling valve which concern on embodiment of this invention. It is a perspective view of the leveling valve. It is sectional drawing which expands a spherical ball bearing and shows the structure. It is explanatory drawing which exaggerates and shows the change of the sliding amount of the steel ball in a piston upper end surface by changing the rotation center height of a lever member.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  1 and 2 show a leveling valve V (control valve) according to an embodiment of the present invention. This leveling valve V includes a surface plate 1 on which equipment (not shown) such as a liquid crystal related manufacturing apparatus is mounted. Usually, in the vibration isolator that is elastically supported by three or more air springs 2 (gas springs), the height of the supported device and the surface plate 1 is kept substantially constant. Air is supplied to or exhausted from each air spring 2.

As shown in FIG. 1 as an example, the air spring 2 is provided with an opening 20a having a circular cross section in the upper wall of a square columnar case 20 as a whole, and a thick disc-shaped piston 21 is inserted therein, An annular diaphragm 22 made of a rubber elastic film is disposed so as to block from the outer periphery of the piston 21 to the peripheral edge of the opening of the case 20, and the air chamber is provided inside the case 20 while holding the piston 21 by the diaphragm 22. Is formed. The outer peripheral portion of the diaphragm 22 is sandwiched between the upper wall of the case 20 and the fastening ring 23 thereon.

  Thus, the air chamber formed in the case 20 is filled with air in a predetermined high pressure state, and the piston 21 is elastically supported by the pressure of the air, and the surface plate 1 and the device acting from above are operated. It is designed to receive the load. By supporting the load by the air pressure in this way, it is possible to support the surface plate 1 and the equipment in a state of being substantially shielded from floor vibration. The structure of the air spring 2 is not limited to that described above, and a bellows can be used instead of the diaphragm 22. In addition, a so-called bellows type air spring that does not include the case 20 and includes a flat top plate on the top of the bellows disposed on the substrate may be used.

  The leveling valve V attached to the air spring 2 as described above includes a valve main body 3 and a drive mechanism 4 attached to the upper portion thereof. In the illustrated example, the valve body 3 includes a cylindrical housing 30 that extends vertically, and a columnar piston 31 that protrudes upward from the upper end of the housing 30 and that can be moved up and down. In response to the vertical movement of 31, the spool 32 connected to the lower end thereof moves, an air supply position for supplying air to the air spring 2, an exhaust position for discharging air therefrom, and a neutral position for not supplying or discharging air Is switched to.

  That is, in the example shown in the figure, air pressurized and supplied from a supply / exhaust port 30a for supplying and discharging air to / from the air spring 2 and an air pressure source (pressure source) outside the figure on the peripheral wall of the housing 30. An air supply port 30b to be supplied and an exhaust port 30c for exhausting air discharged from the air spring 2 are opened. One end of a U-shaped tube 34 is connected to the supply / exhaust port 30a through 33, and the other end of the tube 34 is connected to 35 provided on the housing side wall of the air spring 2, A passage communicates with the air chamber.

  Further, 36 is disposed in the air supply port 30b, and a tube 37 for supplying pressurized air from a pneumatic source such as a pneumatic pump or a reservoir tank (not shown) is connected thereto. In the example shown in the figure, the exhaust port 30c is not disposed, and is open to the atmosphere.

  In the valve body 3 having such a structure, when the spool 32 is in the neutral position, the supply / exhaust port 30a, the intake port 30b, and the exhaust port 30c are cut off, and no air supply or exhaust is performed. If the spool 32 moves downward by the lowering of the valve 31, the air supply / exhaust port 30 a and the air supply port 30 b are connected to supply air from the air pressure source to the air spring 2. On the other hand, when the piston 31 rises and the spool 32 moves upward from the neutral position, the supply / exhaust port 30a and the exhaust port 30c communicate with each other, and the air from the air spring 2 is released into the atmosphere. .

  Then, the drive mechanism 4 is directly turned up and down by the displacement of the surface plate 1 so that the switching of the supply and exhaust by the operation of the piston 31 occurs in conjunction with the displacement of the surface plate 1 in the vertical direction. A lever member 40 that is moved to actuate the piston 31 is provided. In the illustrated example, the lever member 40 is made of a metal square bar, and a base end (right end in the drawing) is rotatably supported on an upper portion of the housing 30 of the valve body 3 via a bracket 41. On the other hand, a level adjusting screw 42 is attached to the front end (left end in the figure) of the lever member 40 so as to penetrate the screw hole 40a (shown only in FIG. 2) and extend in the vertical direction. 1 is in contact with the lower surface.

The bracket 41 includes a rectangular base plate 41a and a hinge member including a pair of upper and lower blocks 41b and 41c disposed on the upper surface of one end (right end in the figure) in the longitudinal direction. The base plate 41 a is superimposed on the upper end surface of the housing 30 together with the mounting bracket 5 for mounting the valve body 3 to the air spring 2, and is fastened together by a tightening ring 38. The mounting bracket 5 is composed of a substantially rectangular base plate 50 and a laterally long side plate 51 welded to one edge thereof, and bolt holes are opened in the left and right side portions of the side plate 51 protruding from the left and right sides of the base plate 50, respectively. Yes.

  On the other hand, the base plate 41a of the bracket 41 is formed with an extending portion extending outward from a portion fastened to the housing 30 by the fastening ring 38 so as to protrude from the base plate 50 of the mounting bracket 5. The lower block 41c of the hinge member is placed on the protruding portion and fastened with screws 41d. The upper and lower blocks 41b and 41c of the hinge member are rotatably connected by a pin 41e, and the base end portion of the lever member 40 is superimposed on the upper surface of the upper block 41b and fastened by a screw 41f. Yes.

  Thus, the axis x of the pin 41e that connects the upper and lower blocks 41b and 41c of the hinge member is the rotation center of the base end portion of the lever member 40, and this rotation center x is shown in FIG. In this way, the valve body 3 is positioned outward from the outer periphery of the upper end surface of the housing 30.

  Further, in this embodiment, a steel ball 43 (spherical body) is disposed at a portion closer to the base end side of the lever member 40 so as to contact the upper end surface of the piston 31. That is, the housing 44a of the spherical ball bearing 44 is fastened to the predetermined portion of the lever member 40 corresponding to the upper side of the piston 31 by the nut 45, and the steel ball 43 is accommodated in the housing 44a so as to be rotatable in the direction. It is supported. When the lever member 40 swings up and down (turns) as described later, the steel ball 43 rolls while sliding on the upper end surface of the piston 31.

  That is, the spherical ball bearing 44 includes a housing 44a having a substantially cylindrical shape with a bowl-shaped opening provided below, and a cover 44b assembled to the lower side, as shown in FIG. And a plurality of balls 44c between the outer peripheral surface of the upper half of the steel ball 43 and the spherical inner peripheral surface (load receiving surface) of the opening facing the steel ball 43. , 44c,... Are arranged to be able to roll. With this structure, the steel ball 43 can roll smoothly while supporting a sufficiently large load.

  Note that the steel ball 43 that rolls while sliding on the upper end surface of the piston 31 is more advantageous in reducing the frictional resistance as the steel ball 43 is larger. Further, the larger the steel ball 43, the smaller the surface pressure with the upper end surface of the piston 31, which is also preferable for reducing frictional resistance and wear.

  Further, in the leveling valve V of this embodiment, the lever member 40 is substantially horizontal as shown in FIG. 1 in the neutral position where neither air supply nor exhaust is performed, and the steel that contacts the upper end surface of the piston 31 as described above. The center of the sphere 43 is generally at the same height as the axis x of the pin 41e at the base end of the lever member 40, that is, the rotation center x of the lever member 40. This is because when the steel ball 43 moves up and down due to the swing of the lever member 40, the displacement in the horizontal direction, that is, the sliding amount of the steel ball 43 on the upper end surface of the piston 31 becomes relatively small. Means that.

Specifically, although exaggerated in FIG. 4, if the center position of the steel ball 43 at the neutral position is lower than the rotation center x of the lever member 40 as indicated by a broken line in FIG. When the lever member 40 pivots downward as shown by the solid line in FIG. 6 and the piston (not shown in the figure) is pushed down by a predetermined amount D by the steel ball 43, the steel ball 43 is moved horizontally. Also, the displacement is relatively large (d in the figure). This means that the sliding amount of the steel ball 43 on the upper end surface of the piston 31 is considerably increased.

On the other hand, in this embodiment, the center of the steel ball 43 is at the same height as the rotation center x of the lever member 40 in the neutral position as shown in FIG. When the steel ball 43 is rotated downward by an angle θ (strictly a little larger) and the piston is pushed down by the same amount D as described above, the horizontal displacement d of the steel ball 43 associated therewith, that is, above the piston 31. The sliding amount of the steel ball 43 on the end face is minimized, and frictional resistance and wear are reduced.

  In order to minimize the sliding amount of the steel ball 43 on the upper end surface of the piston 31, the height of the center of the steel ball 43 and the rotation center x of the lever member 40 is made the same as described above. However, the present invention is not limited to this. For example, if the height of the rotation center x is included between the upper end and the lower end of the steel ball 43, a certain effect can be expected.

  In addition, when the piston 31 is operated up and down by the rotation of the lever member 40 as described above, from the viewpoint of reducing the sliding amount of the steel ball 43 on the upper end surface as much as possible, the lever member is as in this embodiment. It is also advantageous that the rotational center x of 40 is located outward from the outer periphery of the upper end surface of the housing 30 of the valve body 3.

  That is, the fact that the rotation center x of the lever member 40 is located outward from the outer periphery of the upper end surface of the housing 30 of the valve body 3 means that the lever member 4 from the steel ball 43 that contacts the upper end surface of the piston 31. The distance to the rotation center x of the lever 31 is relatively large. This means that the rotation angle (θ in FIG. 4) of the lever member 40 is geometrically the same as the amount of operation of the piston 31 up and down. This means that the sliding amount of the steel ball 43 on the upper end surface of the piston 31 is reduced.

In addition, if the rotation center x of the lever member 40 is moved away from the upper end surface of the valve body 3, wear powder generated around the shaft support portion, that is, around the pin 41 e of the hinge member as the lever member 40 is actuated. , intruded Ri to between or or the piston 31 and the housing 30 attached to the upper end surface of the piston 31, there is no fear of causing trouble.

  Therefore, in the vibration isolator according to this embodiment, for example, the position of the center of gravity changes in the horizontal direction with the operation of the device on the surface plate 1, and the shared load of the air springs 2, 2,. In the case of a large change, the lever member 40 of the leveling valve V rotates downward in the air spring 2 in which the shared load increases and the supporting height decreases as in the conventional general leveling valve. 3 is pushed down to switch to the air supply position, and pressurized air is supplied to the air spring 2.

  On the other hand, in the air spring 2 in which the shared load is reduced and the support height is increased, the lever member 40 of the leveling valve V is rotated upward, the piston 31 is raised, and the air spring 2 is switched to the exhaust position. It comes to exhaust.

  The lever member 40 that swings up and down presses the upper end surface of the piston 31 via the steel ball 43 supported by the spherical ball bearing 44. Since it rolls while sliding on the end face, a smooth operation with a small frictional resistance is realized. As a result, the wear on the upper end surface of the piston 31 is very little, and even if there is wear powder, the rolling of the steel ball 43 is not hindered, so that the above smooth operation is realized over a long period of time. it can.

  In addition, in this embodiment, as described above, the rotation center x of the lever member 40 of the leveling valve V is positioned at the same height as the center of the steel ball 43 and more than the outer periphery of the upper end surface of the housing 30 of the valve body 3. By positioning it outward, it is possible to minimize the sliding amount of the steel ball 43 sliding on the upper end surface in association with the up and down operation of the piston 31, and this also reduces the frictional resistance and wear. It can be done.

  In the above-described embodiment, instead of the spherical ball bearing 44 that holds the steel ball 43 on the lever member 40, a spherical sliding bearing may be used.

Et al is, the lever member 40 as not limited to the leveling valve for swinging (rotating) up and down, but the present invention to the other control valve is to be applied, for example, instead of the air spring 2 nitrogen gas may be Ru with other gas springs, such as by filling a.

  As described above, according to the present invention, the frictional resistance is reduced and the smooth operation of the piston by the lever member can be realized over a long period of time, which is suitable for the leveling valve attached to the air spring of the vibration isolation table, for example. is there.

V Leveling valve (control valve)
1 Surface plate (supported body)
2 Air spring (gas spring)
3 Valve body 30 Housing 30a Supply / exhaust port 30b Air supply port 30c Exhaust port 31 Piston 32 Spool (valve element)
4 Drive mechanism 40 Lever member 43 Steel ball (spherical body)
44 Spherical ball bearing (spherical bearing)
x Rotation center of lever member

Claims (5)

Connected to a gas spring that receives the load of the supported body, for supplying and discharging gas, an air supply port for supplying gas from a pressure source, and for exhausting the gas discharged from the gas spring A control valve drive mechanism comprising an exhaust port,
The control valve includes an air supply position that communicates the air supply port and the air supply / exhaust port, an exhaust position that communicates the air supply / exhaust port and the exhaust port, It can be switched to a neutral position where gas is not supplied or discharged in the middle
A base member is rotatably supported by the housing, and a lever member is provided so that the distal end receives a load of the supported body and rotates in the moving direction of the valve body.
The control valve is provided with a piston movable in the vertical direction in conjunction with the valve body,
A drive mechanism for a control valve, characterized in that a spherical body capable of rolling in an arbitrary direction is supported in contact with the upper end surface of the piston at a portion closer to the base end side of the lever member. Before SL spheroids, it is supported by the lever member via a spherical bearing, the drive mechanism of the control valve according to claim 1.   The drive of the control valve according to claim 2, wherein the spherical bearing is a spherical ball bearing in which a plurality of balls are movably interposed between a spherical body and a spherical load receiving surface supporting the outer periphery thereof. mechanism.   The control valve is arranged such that the valve body and the piston move in the vertical direction, and the height of the spherical body that abuts the upper end surface of the piston when in the neutral position is between the lower end and the upper end. The control valve drive mechanism according to claim 2, wherein the control valve drive mechanism is set to include a height of a rotation center of the lever member base end.   The drive mechanism of the control valve according to any one of claims 1 to 4, wherein a rotation center of the lever member base end portion is positioned outward from an outer periphery of an end surface of the housing of the control valve.

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