KR19980042621A - Air cylinder device - Google Patents

Abstract

An air bearing for holding the sliding portion between the cylinder body, the piston and the rod in a substantially non-contact state by intervening compressed air, and air supply means for supplying compressed air to the air bearing, wherein the air supply means includes: It is connected to two pressure chambers on both sides of the piston and each air bearing through a flow path, respectively, and automatically connects the pressure chamber of the two pressure chambers to which the compressed air is supplied and each air bearing automatically and selectively by the action of air pressure. .

Description

Air cylinder device

The present invention relates to an air cylinder device having a small sliding resistance between a piston and a rod.

A piston and a rod made to slide in the cylinder body, and a pair of ports for supplying and discharging compressed air to the cylinder chambers on both sides of the piston, and the piston and the compressed air supplied to and discharged from the cylinder chamber. The air cylinder apparatus which drives a rod is known conventionally.

However, since the conventional air cylinder device seals the sliding portion between the cylinder body, the piston and the rod with a packing made of synthetic rubber, the sliding resistance is considerably large, and the piston and rod are stopped at a specific position accurately. In the case where it is necessary to make it necessary, it is difficult to accurately determine the stop position.

On the other hand, air bearing is known as making sliding resistance of a sliding part small. This air bearing reduces sliding resistance by interposing compressed air in the sliding part, but requires a dedicated pipe such as a tube for supplying compressed air. Therefore, when the air bearing is attached to the air cylinder as it is, the number of pipes increases and the apparatus becomes complicated, and the tube that is bent and unrolled due to the expansion and contraction of the rod, the movement of the cylinder, and the like is likely to interfere with work.

The main subject of this invention is providing the air cylinder apparatus which reduced the sliding resistance of a piston and a rod by air bearing.

Another object of the present invention is to eliminate the need for a dedicated pipe for supplying compressed air to the air cylinder in the above-described air cylinder apparatus.

In order to solve the above problems, according to the present invention, an air bearing for supporting the sliding portion between the cylinder body, the piston and the rod in a substantially non-contact state by intervening compressed air, and air for supplying compressed air to the air bearing. An air cylinder apparatus provided with a supply means is provided.

The air supply means is connected to each of the two pressure chambers on each side of the piston and each air bearing through an air flow path, so that the pressure chamber and each air bearing on the side to which the compressed air is supplied among the two compression chambers are applied to the action of air pressure. It is configured to connect automatically and selectively.

According to one specific embodiment of the present invention, the air supply means is constituted by a shuttle valve. The shuttle valves are individually connected to the two pressure chambers via the supply air passages, respectively, and are connected to the respective air bearings through the output air passages. By the action of the air pressure supplied into the valve chamber, the valve body closes the supply air passage on the low pressure side, and connects the supply air passage on the high pressure side to the output air passage.

According to another specific embodiment of the present invention, the air supply means is constituted by two check valves. One of the two check valves is provided between one of the two pressure chambers and each air bearing, and the other check valve is provided between the other pressure chamber and each air bearing.

In one embodiment of the present invention, the air supply means is embedded in a piston or a rod, and is in communication with each air bearing through the air passages formed in the piston and the rod.

In another embodiment of the present invention, the air supply means is built in the cylinder body and communicates with each air bearing through the air flow path formed in the cylinder body.

According to the air cylinder device of the present invention having the above-described configuration, since the sliding resistance of the piston and the rod can be reduced by the air bearing, the movement is smooth and pleasant, and as a result, the stop positions of the piston and the rod You can make a high decision.

In addition, since the compressed air is supplied to the air bearing through an internal flow path installed in the piston and the rod or the cylinder body, a dedicated external pipe is not required. Therefore, the number of pipes increases and the apparatus becomes complicated. There is also no problem that the tube, which is bent and straightened in accordance with the expansion and contraction of the rod, the movement of the cylinder, and the like, interferes with work.

1 is a cross-sectional view showing a first embodiment of the present invention.

2 is a cross-sectional view showing a second embodiment of the present invention.

3 is a cross-sectional view showing a third embodiment of the present invention.

4 is a cross-sectional view showing a fourth embodiment of the present invention.

1 shows a first embodiment of an air cylinder apparatus according to the present invention, wherein the air cylinder apparatus 1A has a cylinder body 2 having a cylinder hole 3 therein. The cylinder body 2 comprises a first portion 2a having a dent for the cylinder hole 3 and a second portion 2b covering the dent of the first portion 2a. Both parts 2a and 2b are hermetically connected by connection means, such as a bolt (not shown).

In the cylinder body 2, a through hole 6 passing through the center of the cylinder hole is formed in the first portion 2a and the second portion 2b, and is formed between the hole surface in the through hole. The rod 4 passes through the rod 4 so as to slide therein, and is disposed in the cylinder hole 3 so as to slide therein with a very small gap between the hole surface and the hole surface. Piston 5 is integrally attached.

On the outer surface of the cylinder body 2, a port for individually communicating with the first pressure chamber 12a and the second pressure chamber 12b on both sides of the piston 4 through the air passages 11a and 11b ( 8a and 8b are provided, and these ports 8a and 8b are connected to the compressed air source 13 via electronic pressure proportional control valves 9a and 9b which are one type of air pressure regulating means, respectively.

The proportional control valves 9a and 9b control the current values when the proportional solenoids 10a and 10b are energized, thereby controlling the compressed air supplied from the compressed air source 13 to the pressure chambers 12a and 12b. The pressure can be adjusted to the desired pressure.

On the outer circumferential surface of the rod 4 and the outer circumferential surface of the piston 5, circumferential grooves 16a, 16b constituting the air bearings 15a, 15b are formed, respectively. Rods 4 are formed in these air bearings 15a and 15b, respectively. The air bearings 15a and 15b allow air to be interposed between the rod 4 and the through hole 6 between the hole surface and between the piston 5 and the hole surface of the cylinder hole 3, respectively. As a result, by supporting the aero rod 4 and the piston 5 in a state separated from the hole surface, the sliding resistance can be reduced to a state close to zero by this.

Moreover, the groove | channel 16a provided in the said rod 4 is formed so that it may always be located in the through-hole 6 even if the said rod 4 changes.

In addition, although the air bearing 15a is provided in the position which pinched the piston 5 in the axial direction both sides of the rod 4 in the example of illustration, two or more air bearings can also be provided in each side. . Similarly, two or more air bearings 15b can be provided in the piston 5.

Inside the portion where the piston 5 of the rod 4 is attached, a shuttle valve 17 is provided as air supply means for supplying compressed air to the air bearings 15a and 15b.

The shuttle valve 17 has a valve chamber 18 and a valve body 21 housed in the valve 18. One end side in the axial direction of the valve chamber 18 communicates with the first pressure chamber 12a along the first supply air passage 19a penetrating the rod 4 and the piston 5, and thus in the axial direction. The other end side communicates with the 2nd pressure chamber 12b by the same 2nd supply air flow path 19b. Furthermore, in this valve chamber 18, a plurality of output air flow paths 20 are radially opened at positions between the two air flow paths 19a and 19b, and a part of these output air flow paths 20 is loaded. The two air bearings 15a and 15a of the rod are connected to each other by branch air passages 20a and 20a provided in the branch so that the remaining output air passages 20 are provided with the rod 4 and the piston 5. ) Is directly communicated with the air bearing 15b of the piston 5.

The plurality of output air flow paths 20 do not necessarily need to be provided radially from the valve chamber 18, but only one having branch air flow paths 20a and 20a may be provided.

In the air cylinder apparatus 1A of the first embodiment, the proportional solenoid 10a of the first proportional control valve 9a is energized and the proportional solenoid 10b of the second proportional control valve 9b is not energized. In this case, the compressed air having a pressure proportional to the amount of energization is supplied from the first proportional control valve 9a to the first pressure chamber 12a, and the compressed air of the second pressure chamber 12b is controlled in a second proportional control. It is discharged | emitted from the valve 9b to the exterior. For this reason, the rod 4 and the piston 5 move to the position shown in a figure.

At this time, in the shuttle valve 17, the high pressure compressed air in the second pressure chamber 12a flows into the valve chamber 18 through the first supply air passage 19a, and the valve body 21 The second supply air flow path 19b of the low compression is closed by slid. At the same time, the compressed air flows into the grooves 16a and 16b of the respective air bearings 15a and 15b through the output air passage 20 and the branch air passage 20a. For this reason, the rod 4 and the piston 5 are substantially in these through holes 6 and the cylinder hole 3 by the compressed air interposed in the space | interval between the through hole 6 and the cylinder hole 3. Is supported in a non-contact state, and the state is shifted to the position. Therefore, the sliding resistance of these rods 4 and the piston 5 approaches almost zero, and the movement is performed very smoothly.

The compressed air supplied into the grooves 16a and 16b of each of the air bearings 15a and 15b leaks very small from the gap to the outside, but these gaps are extremely small compared to the volume of the pressure chamber 12a. The said amount of leak is small, and the air pressure of the pressure chamber 12a does not fall. Even in the case of lowering, the air pressure is adjusted by the action of the proportional control valve 9a.

The rod 4 and the piston 5 have an action force of the air pressure of the compressed air supplied to the pressure chamber 12a, the weight of the rod 4 and the piston 5 and the load attached to the rod 5 (Fig. () Is omitted in the position where the balance of weight is balanced. The stop position can be controlled by the current value of the proportional solenoid 10a of the proportional control valve 9a, but the stop of the rod 4 and the piston 5 by the action of the air bearings 15a and 15b. The position can be determined precisely.

Contrary to the above, when the first proportional control valve 9a is turned off and the second proportional control valve 9b is turned on, compressed air is supplied to the second pressure chamber 12b. 5) and the rod 4 are switched to the position opposite to FIG. At the same time, also in the shuttle valve 17, the valve main body 21 moves to the position opposite to FIG. 1 by the compressed air which flows into the valve chamber 18 from the 2nd supply air flow path 19b, The first supply air passage 19a is closed, but since the compressed air from the second supply air passage 19b is supplied to each air bearing 15a, 15b, the piston 5 and the rod 4 Movement and stop) are smooth and good.

Thus, since each of the air bearings 15a and 15b is always supplied with a part of the compressed air supplied to the two pressure chambers 12a and 12b, the movement of the rod 4 and the piston 5 is light. Smooth and precise stop position control can be performed. In addition, since the compressed air is supplied to each air bearing through the air flow paths provided in the rod 4 and the piston 5, a dedicated structure is not required and the pipe is bent. It can eliminate the effect of loosening and unfolding on the switching action.

Furthermore, since the shuttle valve 17 is made in the center portion of the rod 4, the radial weight balance of the rod hardly changes, and as a result, the load 4 and the piston 5 are unevenly loaded. This does not work.

Fig. 2 shows a second embodiment of the present invention. The second embodiment differs from the first embodiment in that the air supply means is composed of a check valve instead of a shuttle valve. That is, in the air cylinder apparatus 1b of this 2nd Example, the 1st supply air flow path 19a which communicates with the 1st pressure chamber 12a, the output air flow path which passes through each air bearing 15a, 15b ( The first check valve 27a is installed at the position immediately before the point where it joins 20) so that the compressed air flows only in the direction from the first pressure chamber 12a toward the air bearings 15a and 15b. The second check valve 27b is positioned at the position immediately before the point where the second supply air passage 19b communicating with the second pressure valve 12b joins the output air passage 20, and the second pressure chamber ( 12b) is provided so that compressed air can flow only in the direction toward the air bearings 15a and 15b.

Since the other structure and operation in this 2nd Example are substantially the same as 1st Example, the same code | symbol as 1st Example is attached | subjected to the same principal part of drawing, and detailed description is abbreviate | omitted.

Moreover, in the said 1st and 2nd Example, since the rod 4 and the piston 5 connected the center of the annular piston 5 in the form where the rod 4 penetrated, the said rod Although each of the shuttle valves 17 and check valves 27a and 27b, which are air supply means, is provided inside (4), each of the rods 4 divided into two parts on both sides of the piston 5, which does not have an annular shape, is provided. When the part is attached, it is natural that the air supply means is installed inside the piston 5.

Fig. 3 shows a third embodiment of the present invention, which differs from the first embodiment in that the air cylinder device 1C of this third embodiment has made the shuttle valve 17 into the cylinder body 2. . That is, a valve chamber 18 is formed between the first portion 2a and the second portion 2b of the cylinder body 2 to accommodate the valve body 21, thereby supplying air passages 19a and 19b. ), The output air flow path 20 and the branch air flow path 20a are all formed in the cylinder body 2. Moreover, the circumferential grooves 16a and 16b constituting the air bearings 15a and 15b are also formed on the cylinder body 2 side.

Therefore, the rod 4 and the piston 5 need not be machined, so the structure is simple.

Since the other structure and operation | movement of the said 3rd Example are substantially the same as 1st Embodiment, the same code | symbol as 1st Embodiment is attached | subjected to the same principal part of drawing, and detailed description is abbreviate | omitted.

Fig. 4 shows a fourth embodiment of the present invention, which differs from the third embodiment in that the air cylinder apparatus 1D uses a check valve as air supply means. That is, the first check valve (1) at the position just before the confluence of the first supply air passage (19a) through the first pressure chamber (12a) with the output air passage (20) through the air bearings (15a, 15b). 27a) is arranged so that compressed air can flow only in the direction from the first pressure chamber 12a toward the air bearings 15a and 15b, and the second supply air passage (2) through the second pressure chamber 12b ( 19b), the compressed air flows only in the direction toward the air bearings 15a and 15b from the second pressure chamber 12b to the second check valve 27b at the position immediately before the confluence point with the output air passage 20. I placed it so that I could.

Since the other structures and operations in this fourth embodiment are substantially the same as in the third embodiment, the same reference numerals as in the third embodiment will be given to the same major parts in the drawings, and the detailed description thereof will be omitted.

In the third and fourth embodiments, since the air supply means, all the air flow paths and the grooves of the air bearings can be provided in the cylinder body 2, the configuration is simple, the processing is easy, and the piston stroke It is especially valid if is short.

The air cylinder apparatus of each said embodiment is not limited to the usage method of moving the rod 4 and the piston 5, etc. as shown, For example, it installs in a horizontal direction, and right and left the rod and piston, for example. Of course, it is also possible to use such a method. In this case, when the rod and the piston are driven to the predetermined positions, the rods and the piston can be stopped at the predetermined positions by equalizing the air pressure in the pressure chambers 12a and 12b, and the air bearings 15a and 15b Since there is almost no sliding resistance, the positioning can be performed precisely.

Although not shown, in each of the above embodiments, a voltage divider and a positioning sensor such as a linear encoder are attached to the rod, and the amount of current supplied to the rod is fed back to adjust the amount of energization of the proportional solenoids 10a and 10b. Alternatively, by controlling the air pressure of the compressed air for driving the cylinder by the air servo valve, the stop positions of the rod and the piston can be determined precisely.

According to the experiment, in the case of the known air cylinder apparatus using synthetic rubber packing, the positioning of about 0.1 mm unit is not possible, but in the case of the air cylinder apparatus of the present invention using the air bearing in this way, the precision of 0.001 mm unit is Positioning is possible.

Claims (6)

A piston slidingly inserted into the cylinder body, and a rod integral with the piston, A pair of ports for supplying or discharging compressed air to two pressure chambers on both sides of the piston, An air bearing formed on the sliding portion between the piston and the rod and the cylinder body, and supporting the piston and the rod and the cylinder body in a substantially non-contact state by intervening compressed air; An air passage connecting each of the pressure chambers and each bearing; And an air supply means which is installed in the middle of the air passage and automatically and selectively connects the pressure chamber on the side to which the compressed air is supplied and each air bearing by the action of air pressure. The air supply means according to claim 1, wherein the air supply means is constituted by a shuttle valve, and the valve chambers of the shuttle valves are individually connected to the two pressure chambers through a supply air passage, respectively, and an output air passage is provided. The valve main body connected to each air bearing through the valve chamber closes the supply air passage on the low pressure side by the action of the air pressure supplied into the valve through one supply air passage, thereby supplying the high pressure side. An air cylinder device, characterized in that for connecting the air flow path for the output air flow path. The said air supply means is comprised by two check valves, One check valve is provided between one pressure chamber and each air bearing, and the other check valve is the other. Air cylinder device, characterized in that is installed between the pressure chamber and each air bearing. 4. An air cylinder apparatus according to claim 2 or 3, wherein said air supply means is built in a piston or rod and communicates with each air bearing through said air flow path formed in these pistons and rods. The air cylinder apparatus according to claim 2 or 3, wherein the air supply means is built in the cylinder body, and communicates with each air bearing through the air flow path formed in the cylinder body. An air cylinder apparatus according to claim 1, wherein said air supply means is built in a cylinder body and communicates with each air bearing through said air flow path formed in said cylinder body.