JPS6348829Y2 - - Google Patents

Description

[Detailed Description of the Invention] Technical Field The present invention relates to an air spring height control valve suitable for use in a vibration isolation table on which precision measuring instruments, precision processing machines, etc. are mounted.

Prior Art Fig. 1 is a partial schematic side view showing an example of a vibration isolation table on which the air spring height control valve according to the present invention is used, in which 1 is a mounting plate on which precision equipment is mounted;
is an air spring, 3 is an auxiliary air reservoir connected to the air spring 2, 4 is a probe fixed to the mounting plate 1, 5 is a compressed air supply pipe, 6 is a control valve, 7 is the control valve 6 and the auxiliary air A pipe that connects the reservoir 3. As is well known, precision equipment is mounted on the mounting plate 1, and in this case, the mounting plate is used to prevent external vibrations from being transmitted to the precision equipment. 1 is elastically supported by an air spring 2. Then,
In the above-mentioned vibration isolation table, there is a problem if the level of the mounting plate 1 fluctuates depending on the weight of the precision equipment mounted on the mounting plate 1. The probe 4 and the control valve 6 are provided to solve this problem. For example, when the weight of precision equipment is heavy, the level of the mounting plate 1 is lowered and the probe 4 is lowered accordingly. The level also decreases, but when the probe 4 is lowered, the supply valve of the control valve 6 operates and compressed air from a compressed air source (not shown) is supplied to the auxiliary air reservoir 3 through the pipe 5, control valve 6, and pipe 7, and the air is supplied to the auxiliary air reservoir 3. Increase the pressure within spring 2. In this way, when the pressure inside the air spring 2 increases, the mounting plate 1
rises, and the probe 4 rises accordingly. When the probe 4 reaches a predetermined level, the supply valve of the control valve 6 operates to stop the supply of air into the air spring 2, and the mounting plate 1 follows. precision equipment is maintained at its predetermined level. On the other hand, if the weight of the precision equipment mounted on the mounting plate 1 is light, the mounting plate 1 and the probe 4 will rise, the exhaust valve of the control valve 6 will open, and the air in the auxiliary air reservoir 3 will be discharged from the pipe 7. It is exhausted to the atmosphere through the exhaust valve of the control valve 5, and the air pressure in the air spring 2 is reduced. In this way, when the air pressure in the air spring 2 decreases, the mounting plate 1 descends, and the probe 4 also descends accordingly. When the probe 4 reaches a predetermined level, the exhaust valve of the control valve 6 is closed and the air is discharged. The discharge of the mounting plate 1 and therefore the precision equipment is maintained at its predetermined level. The control valve according to the present invention has the same function as the control valve 6 to maintain the mounting plate 1 at a predetermined level, but the conventional control valve was mainly developed to maintain the level of a vehicle. Since the control valve uses a control valve, the transmission of vibration through the control valve is large for use as a high-precision vibration isolation table. There were drawbacks such as large variations in the reproducibility of positional accuracy and a large amount of compressed air consumption due to an excessively large air flow rate.

Purpose This invention was made to solve the above-mentioned drawbacks of the conventional device.In particular, the movement of the valve stem of the control valve is lightened to prevent vibrations from the outside, that is, from the floor, from hitting the precision equipment on the mounting board. This was done to prevent the transmission of air, reduce the amount of compressed air used, and further improve the reproducibility of level accuracy.

Configuration Figures 2 to 4 are side sectional views showing each operating state of the control valve according to the present invention. Figure 4 shows the situation when the precision equipment is heavy. As shown in the figure, the control valve according to the present invention is equipped with a lever or a swing plate 12 pivotally connected to the upper end of the valve body 10 with a pin 11, and the swing plate 12 always keeps the probe 4 connected. They are always urged upwardly by spring 13 to engage. A chamber 15 is provided inside the valve body 10 and houses a valve rod 14 that can be raised and lowered through the valve body. 15, and a port 18 bored on the other side of the valve body 10 directly communicates with the chamber 15.
is connected to. The pipe 5 is connected to the port 16, and the pipe 7 is connected to the port 18. Therefore, an air source (not shown) is connected to the port 16 via the pipe 5, and the auxiliary air reservoir 3 is connected to the port 18 via the pipe 7.
The valve stem 14 housed in the chamber 15 is always urged upward by a spring 19. A valve seat 20 for opening and closing the communication passage 17 is fixed to the valve stem 14, and the valve seat 20 and the communication passage 17 constitute a supply valve for supplying working air into the air spring 2. There is. The upper center of the valve stem 14 is a valve head 21 formed in a nozzle shape, and a passage 22 that opens into the valve head 21 is provided at the center of the valve stem 14. A seal member 23 is attached to the lower surface of the swing plate 12 as a valve body for the valve head 21. It constitutes a discharge valve. Therefore, if the mounting plate 1 now moves to a higher position than the equilibrium state shown in FIG. The air in the air spring 2 enters the port 18 through the auxiliary air reservoir 3 and the air pipe 7, and then passes through the passage 22 in the valve head 21 to the atmosphere. released inside. Therefore, the inside of the air spring 2 is pushed down, the mounting plate 1 is lowered, and the probe 4 is also lowered, so that the swing plate 12 is pushed down. As a result, the passage 22 of the valve head 21 is closed and the release of air from within the air spring 2 is stopped, and the mounting plate 1 no longer moves downward and stops at the equilibrium state shown in FIG. 3. On the other hand, when the mounting plate 1 is displaced downward from the equilibrium state shown in Fig. 3 (in the case of Fig. 4 in which the mounted equipment is heavy), the swing plate 12 is pushed down by the lowering of the probe 4, causing the valve head to move downward. 21 is pushed down, the valve seat 20, which is integrated with the valve stem 14, also moves downward. As a result, the communication path 17 is opened, the chamber 15 and the port 16 communicate with each other, and the port 16 is communicated with the chamber 15 through the pipe 5.
Compressed air is fed into the chamber 15 from an air source communicating with the chamber 15 and is further inserted into the air spring 2 via the pipe 7. Therefore, the inside of the air spring 2 is raised and the mounting plate 1 is lifted upward. Therefore,
The probe 4 integrated with the mounting plate 1 rises, and the swing plate 1
2 is pushed up by the spring 13 to follow the probe 4, and the valve stem 14 is also pushed up by the spring 19 so that the valve seat 20 closes the communication passage 17, resulting in the equilibrium state shown in FIG.

Effects As is clear from the above explanation, according to the present invention, (1) In a high-performance vibration isolation table, it is necessary to prevent floor vibration from being transmitted from the air spring height control valve to the mounted equipment. To achieve this, it is preferable to make the vertical movement of the valve stem that supplies and exhausts compressed air as light as possible; however, in the present invention, the valve stem penetrates the valve body with the same diameter as the valve stem. Therefore, no pressure difference between the air chamber pressure and atmospheric pressure is applied to the valve stem, and therefore the valve stem can be moved easily.

(2) When in equilibrium, both the exhaust port and the air supply port are closed and compressed air consumption stops, and compressed air is consumed only when the valve stem moves, so the overall amount of compressed air used is less.

(3) Variations in the level accuracy of the vibration isolation table are proportional to the range in which the valve stem can move when the control valve is in its neutral state, that is, when the air supply and exhaust ports are sealed. The level accuracy can be made with good reproducibility, and furthermore,
The accuracy of reproducibility can be increased by moving the position of the probe toward the hinge.

There are advantages such as

[Brief explanation of the drawing]

FIG. 1 is a partial schematic side view showing an example of a vibration isolation table to which the air spring height control valve according to the present invention is applied, and FIGS. 2 to 4 show various operating states of the control valve according to the present invention. FIG. DESCRIPTION OF SYMBOLS 1...Mounting plate, 2...Air spring, 3...Auxiliary air reservoir, 4...Probe, 6...Control valve, 10...
... Valve body, 14... Valve stem.

Claims (1)

[Scope of utility model registration request] A mounting plate for placing an object such as a device, an air spring support device elastically supporting the mounting plate, and supplying compressed air into the air spring by detecting a level change of the mounting plate. or a control valve for discharging the air in the air spring to maintain a constant level of the mounting plate, the control valve comprising a valve body;
a rocking plate having a discharge port valve seat rotatably attached to the valve body and displaced in accordance with level fluctuations of the mounting plate; A valve stem having a discharge port facing the valve seat for the discharge port, and a spring member disposed in a chamber formed in the valve body and pressing the valve stem toward the rocking plate. The valve stem is configured such that the outlet is connected to the air spring chamber through the air passage bored through the valve stem and the chamber in the valve body, and is integrated with the valve stem in the chamber of the valve body. an inlet valve seat, the valve body has a valve head that faces the inlet valve seat of the valve stem in the chamber and has a passage communicating with an air pressure source, and
The air spring height control valve is characterized in that the valve stem is vertically movably disposed in the valve body through a through hole provided in the valve body and having the same diameter as the valve stem.