JP2010242915A - Air cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air cylinder which exhibits at a low cost an air-purge function for inhibiting the intrusion of foreign matters by eliminating the foreign matters such as spatters, dust, chips or the like adhering to a rod. <P>SOLUTION: An annular passage 21 which is made to communicate with the outside of an air cylinder 1 via an opening 20 of a penetration hole 7 is formed between the penetration hole 7 which makes the rod 5 in a rod cover 8 air-tightly and slidably penetrate it and the external peripheral face of the rod 5, and an exhaustion passage 15 which is connected to an air supply/exhaustion port 11 of a cylinder chamber 2 via a rapid exhaustion valve 14, and circulates air discharged from the cylinder chamber 2, is connected to an air supply port 23 which is formed at the annular passage 21. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an air cylinder, and more specifically, an air cylinder having an air purge function that removes foreign matter such as welding spatter, dust, and chips adhering to a rod and prevents the foreign matter from entering the inside. It is about.

Conventionally, an air cylinder has been widely used as an actuator for various automatic machines, for example, and is provided with a piston fixed to a rod and reciprocating in a cylinder chamber, and an end of the cylinder so that the rod can slide freely. A rod cover having a through hole that supports and penetrates the cylinder chamber to the outside; and an annular seal member that maintains airtightness between the through hole and the rod in the through hole. Is common.
By the way, the air cylinder is often used in an environment in which foreign matters such as welding spatter, dust, and chips are easily scattered. Therefore, with the reciprocation of the piston, the foreign matter adhering to the outer peripheral surface of the rod enters the seal member and the cylinder chamber through the gap between the rod cover through-hole and the rod, causing friction. Increasing the resistance, accelerating the wear of each part to reduce the airtightness, accelerating the corrosion, and the like result in a problem that the part replacement cycle and the product life are shortened.

In order to solve such a problem, for example, Patent Documents 1 to 3 include an air purge that supplies compressed air to a gap formed between a rod cover and a rod to remove foreign matters attached to the rod. An air cylinder is disclosed.
However, these conventional air purge-equipped air cylinders require an air purge dedicated air source separately from the driving air pressure source or supply the compressed air supplied from the driving air pressure source. Since part of the air is used, there is a problem that initial cost and running cost increase due to increase in the size of equipment and increase in the amount of compressed air consumed.

Japanese Utility Model Publication No. 56-44884 Japanese Utility Model Publication No. 63-135209 Japanese Utility Model Publication No. 08-3684

  Accordingly, an object of the present invention is to realize an air purge function that removes foreign matter such as welding spatter, dust, and chips adhering to the rod and prevents the foreign matter from entering the interior at a low cost. It is to provide an air cylinder.

In order to solve the above-described problems, according to the present invention, a piston that reciprocates in the cylinder chamber in the axial direction by supplying and discharging compressed air, and a rod that extends in the axial direction relative to the piston and reciprocates together with the piston. A rod cover provided at the axial end of the cylinder chamber and provided with a through hole for slidably supporting the rod; and provided in the through hole and airtight and slidable with respect to the rod An annular seal member that is in contact with the cylinder, and an exhaust passage that is connected to a port established in the cylinder chamber and distributes exhaust air discharged from the cylinder chamber as the piston reciprocates. The rod cover has a first end that faces the cylinder chamber in the axial direction and a second end that faces the outside of the air cylinder, and the through hole has the first end. And an annular channel that is open to the second end and communicates with the outside of the air cylinder, on the second end side of the through-hole from the seal member. It is formed between the through hole and the rod, and the annular flow path is connected to the exhaust flow path, and an air supply port for supplying the exhaust air to the annular flow path is opened.
An air cylinder is provided.

In the air cylinder according to the present invention, the cylinder chamber is partitioned into a first chamber and a second chamber by the piston, and the rod cover is an axial end of the cylinder chamber on the first chamber side. The exhaust flow path is connected to the port established in the second chamber, and exhaust air discharged from the port as the piston moves toward the second chamber side It is desirable to supply the annular channel through the exhaust channel.
In addition, the annular flow path is prevented from entering the first end side of the foreign substance attached to the rod into the through hole on the second end side of the air supply port in the annular flow path. It is desirable that an annular wiper that allows the discharged air supplied to the second end to flow to the second end side is provided in a slidable contact with the rod.

  Furthermore, in the air cylinder according to the present invention, the port opened in the second chamber is a supply / exhaust port, and a quick exhaust valve is connected to the port via a supply / exhaust flow path. It is desirable that an air supply passage through which compressed air is supplied from an air pressure source and the exhaust passage are connected to the exhaust valve so that communication with the air supply / exhaust passage can be switched.

  The annular flow path is formed at a substantially constant depth in the axial direction and the circumferential direction with respect to the through hole in a region from the second end side to the opening of the second end with respect to the seal member. The gap between the enlarged diameter portion and the rod may be formed to have a substantially constant width, and the air supply port may be provided in the enlarged diameter portion of the through hole. The axial end of the two chambers may be closed by a head cover.

  According to the air cylinder of the present invention, the air purge function that removes foreign matter such as welding spatter, dust, and chips adhering to the rod and prevents the foreign matter from entering the inside is provided along with the reciprocating motion of the piston. By using the exhaust air discharged from the cylinder chamber, it can be realized at low cost. In particular, according to the air cylinder of claim 2 of the present invention, when the rod is retracted in the direction of the cylinder chamber, the exhaust air is blown against the rod to remove foreign matter adhering to the rod. Therefore, it is possible to more efficiently and reliably prevent the foreign matter from entering the inside.

It is sectional drawing which shows the air cylinder which concerns on one Embodiment of this invention. FIG. 2 is a schematic pneumatic circuit diagram showing the air cylinder of FIG. FIG. 2 is a schematic pneumatic circuit diagram showing the air cylinder of FIG. 1 when the rod is retracted.

1 to 3 show an embodiment of an air cylinder according to the present invention.
As shown in FIG. 1, the air cylinder 1 is formed in a cylindrical shape having both ends open, and includes a cylinder body 3 having a cylinder chamber 2 extending in the axial direction inside, and supply of compressed air to the cylinder chamber 2. The piston 4 that reciprocates in the cylinder chamber 2 in the axial direction by the exhaust, the rod 5 that has a proximal end fixed to the piston 4 and extends in the cylinder chamber 2 in the axial direction, and the shaft of the cylinder chamber 2 A through-hole that is provided at one end in the direction and seals one opening of the cylinder body 3 in an airtight manner, and supports the rod 5 by being inserted in an airtight and reciprocating manner so as to be led out of the air cylinder 1. 7 and a head cover 9 provided at the other axial end of the cylinder chamber 2 and hermetically closing the other opening of the cylinder body 3.

  The cylinder chamber 2 is formed in a substantially circular cross section, divided into two by the piston 4, and a first chamber 2 a formed between the rod cover 8 and a head cover 9. It is divided into two chambers 2b. The first chamber 2a and the second chamber 2b are provided with first and second air supply / exhaust ports 10 and 11 for supplying and discharging compressed air to and from the chambers 2a and 2b, respectively. In the figure, reference numeral 4a denotes an annular elastic seal member attached to the outer periphery of the piston 4, and the piston 4 is fitted into the cylinder chamber 2 in an airtight and reciprocating manner by the seal member 4a. . Reference numeral 4b in the figure denotes an annular magnet that is also attached to the outer periphery of the piston 4 so that the axial position of the piston 4 can be detected by an external sensor (not shown).

  The first air supply / exhaust port 10 has a first air supply / exhaust flow path 12 for circulating both compressed air supplied to the first chamber 2a and exhaust air discharged from the first chamber 2a. Are connected via a first quick fitting 10a. On the other hand, the second air supply / exhaust port 11 has a second air supply for circulating both compressed air supplied to the second chamber 2b and exhaust air discharged from the second chamber 2b. One end of the exhaust passage 13 is connected via the second quick fitting 11a. The other end of the air supply / exhaust flow path 13 is connected to the output port A of the quick exhaust valve 14 having an output port A, an input port P, and an exhaust port R. One end of an exhaust passage 15 for circulating the exhaust air discharged from the chamber 2b is connected, and an air supply passage 16 for circulating the compressed air supplied to the second chamber 2b is connected to the input port P. Are connected at one end.

2 and 3, the other ends of the first air supply / exhaust flow path 12 and the air supply flow path 16 are connected to a switching valve (for example, a 5-port switching valve as shown) V. By switching the switching valve V, the first supply / exhaust flow path 12 and the supply flow path 16 can be communicated with the air pressure source Pa or the atmosphere.
At this time, as shown in FIG. 2, the quick exhaust valve 14 closes the exhaust port R and closes the input port P when the supply flow path 16 is communicated with the air pressure source Pa by the switching valve V. When the output port A is in communication with the supply flow path 16 to the atmosphere by the switching valve V as shown in FIG. 3, the input port P is closed and the output port A and the exhaust port are closed. R is configured to communicate with R.

  By the way, the rod cover 8 has, in the axial direction, a first end 8a facing the cylinder chamber 2 (specifically, the first chamber 2a) and a second end 8b facing the outside of the air cylinder 1. The through hole 7 is provided between the first end 8a and the second end 8b. Further, the rod cover 8 has an annular seal member 17 on the outer periphery on the first end 8a side, and is airtightly fitted to the end portion of the cylinder chamber 2 on the first chamber 2a side, and a ring or the like. The fixing means 18 is fixed so as not to be removable.

  A lip-shaped annular seal member 19 made of an elastic body is fitted into the annular groove in the through hole 7, and the inner peripheral portion thereof is airtight and slidable on the outer peripheral surface of the rod 5. The rod 5 is attached to the air cylinder 1 in accordance with the reciprocating motion of the piston 4 while maintaining an airtight state between the through hole 7 and the rod 5. While moving forward in the external direction, it is possible to move backward in the direction of the cylinder chamber 2.

Further, an annular flow passage communicating with the outside of the air cylinder 1 through the opening 20 of the second end 8b of the rod cover 8 is located closer to the second end 8b than the annular seal member 19 in the through hole 7. 21 is formed by making the gap between the inner circumferential surface of the through hole 7 and the outer circumferential surface of the rod 5 larger than the gap in the region where the seal member 19 is in sliding contact with the rod 5.
Specifically, in the through hole 7, the through hole 7 extends from the position closer to the second end 8 b of the rod cover 8 than the seal member 19 to the opening 20 of the second end 8 b of the rod cover 8. On the other hand, an enlarged diameter portion 22 formed at a substantially constant depth in the axial direction and the circumferential direction is provided, and a gap between the inner circumferential surface of the enlarged diameter portion 22 and the outer circumferential surface of the rod 5 The annular channel 21 having a substantially constant width in the axial direction and the circumferential direction is formed.

The exhaust air discharged from the cylinder chamber 2 as the piston 4 reciprocates is introduced into the annular channel 21 at a position corresponding to the annular channel 21 in the rod cover 8. The air supply port 23 is opened.
Specifically, the air supply port 23 is opened substantially perpendicularly to the outer peripheral surface of the rod 5 at a position near the first end 8a in the enlarged diameter portion 22 of the through hole 7, and the air supply port The other end of the exhaust passage 15 for circulating the exhaust air discharged from the second chamber 2b of the cylinder chamber 2 is connected to the port 23 via a quick fitting 23a.

  Further, in the air cylinder 1 according to the present embodiment, an annular wiper 24 is provided at a position on the second end 8 b side of the annular flow path 21 with respect to the air supply port 23. The wiper 24 is for collecting and collecting foreign matter adhering to the outer peripheral surface of the rod 5 together with the backward movement of the rod 5, and fitting the outer peripheral portion into an annular groove provided in the enlarged diameter portion 22. The inner peripheral portion of the rod 5 is attached in a slidable contact with the outer peripheral surface of the rod 5. The wiper 24 is made of a flexible porous material having air permeability such as felt, and prevents the foreign matter from entering the first end 8a side beyond the wiper 24. On the other hand, the exhaust air introduced into the annular flow channel 21 from the air supply port 23 is configured to allow the air to pass through the wiper 24 to the second end 8b side.

  Similarly, the head cover 9 has an annular seal member 25 on its outer periphery, and is fitted into the end of the cylinder chamber 2 on the second chamber 2b side so as to be appropriately fixed (not shown). It is fixed so as not to be removable by means.

Next, the operation of the air cylinder according to the present embodiment will be described with reference to FIGS.
First, as shown in FIG. 2, in a state where the air pressure source Pa is communicated with the supply flow channel 16 and the first supply / exhaust flow channel 12 is communicated with the atmosphere via the switching valve V, The rapid exhaust valve 14 communicates the second supply / exhaust flow path 13 with the supply flow path 16. Accordingly, compressed air from the air pressure source Pa is supplied to the second chamber 2b of the cylinder chamber 2, and the piston 4 and the rod 5 are driven forward in the direction toward the first chamber 2a (left direction in the figure), and the first chamber Exhaust air from 2a is released to the atmosphere via the switching valve V.

  On the other hand, by switching the switching valve V, as shown in FIG. 3, the air pressure source Pa is communicated with the first air supply / exhaust flow path 12 through the switching valve V, and the supply flow path 16 is In the state where the air is communicated with the atmosphere, the second air supply / exhaust flow path 13 is communicated with the exhaust flow path 15 by the quick exhaust valve 14. Therefore, the compressed air from the air pressure source Pa is supplied to the first chamber 2a of the cylinder chamber 2, and the piston 4 and the rod 5 are driven backward in the direction of the second chamber 2b (right direction in the figure), and the second chamber The exhaust air from 2b is supplied as purge air to the annular flow channel 21 via the quick exhaust valve 14 and the exhaust flow channel 15.

  Therefore, according to the air cylinder 1 according to the present embodiment, solid foreign matters such as welding spatter, dust, and chips, and liquid foreign matters such as cutting oil and moisture (that is, the air cylinder 1 of the air cylinder 1). Even if it is used in an environment where foreign matter that may reduce the function or shorten the life of the air cylinder 1 such as increased frictional resistance, wear of parts, accelerated corrosion, etc. Exhaust air discharged from the cylinder chamber 2 as the piston 4 reciprocates is supplied to the annular flow path 21 as purge air, and also to the outside of the air cylinder 1 through the opening 20 of the second end 8 b of the rod cover 8. By blowing out, the foreign matter adhering to the outer peripheral surface of the rod 5 can be removed. As a result, the foreign matter can be prevented from entering the air cylinder 1 through the opening 20. Further, as described above, the air discharged from the cylinder chamber 2 is used as the purge air, and a pneumatic source dedicated to the purge air is prepared separately from the driving pneumatic source Pa, or the driving compression supplied from the pneumatic source Pa is used. Since there is no need to use part of the air, the initial cost and running cost can be suppressed, and the air purge function can be realized at low cost.

  Particularly in this embodiment, when the rod 5 moves backward in the direction of the cylinder chamber 2, the exhaust air from the chamber (ie, the second chamber 2 b) contracted by the piston 4 is supplied to the annular flow path 21. Since it is configured to supply and remove the foreign matter adhering to the rod 5, it is possible to more efficiently and reliably prevent the foreign matter from being drawn into the air cylinder 1 together with the rod 5. Is possible.

  Further, by providing the wiper 24 in the annular flow path 21 as described above, it is possible to more reliably prevent foreign matter adhering to the rod 5 from entering the air cylinder 1 in combination with the air purge function. . Particularly in the present embodiment, when the rod 5 is moved backward, the foreign matter can be removed through the opening 20 of the second end 8b of the rod cover 8 with the purge air while collecting the foreign matter with the wiper 24. Therefore, it is possible to prevent the foreign matter scraped off from the wiper 24 from accumulating and climbing over the wiper 24 toward the second end 8b. As a result, it is even more efficient for the foreign matter to enter the air cylinder 1. It is possible to prevent the situation properly and reliably.

As described above, the embodiments of the air cylinder according to the present invention have been described in detail. However, the present invention is not limited to the above-described embodiments, and various design changes can be made without departing from the gist of the present invention. It is.
For example, in the above embodiment, the quick exhaust valve 14 is interposed only in the second supply / exhaust flow path 13 connected to the second chamber 2b of the cylinder chamber 2, but the first exhaust connected to the first chamber 2a. The air supply / exhaust flow path 12 may be interposed, and at that time, the exhaust air discharged from the first chamber 2a may also be introduced into the annular flow path 21. It is also possible to configure so that only the exhaust air from the first chamber 2a is introduced into the annular flow path 21. In addition, it is possible to perform a surface treatment so that foreign matters are less likely to adhere to the outer peripheral surface of the rod 9, thereby further improving the effect of the air purge.
Further, the switching valve V is not limited to the five-port switching valve as in the present embodiment, and other switching valves can be employed, and the air cylinder is a double-acting type as in the present embodiment. It is not limited to this, and it may be a single action type.

DESCRIPTION OF SYMBOLS 1 Air cylinder 2 Cylinder chamber 4 Piston 5 Rod 7 Through-hole 8 Rod cover 8a 1st end 8b 2nd end 10 1st air supply / exhaust port 11 2nd air supply / exhaust port 15 Exhaust flow path 19 Seal member 20 Opening 21 Annular flow Road 23 Air supply port

Claims (6)

A piston that reciprocates in the cylinder chamber in the axial direction by supplying and discharging compressed air;
A rod extending axially relative to the piston and reciprocating with the piston;
A rod cover provided at an axial end of the cylinder chamber and provided with a through hole for slidably supporting the rod;
An annular seal member provided in the through-hole and brought into airtight and slidable contact with the rod;
An exhaust passage that is connected to a port established in the cylinder chamber and circulates exhaust air discharged from the cylinder chamber as the piston reciprocates;
An air cylinder comprising:
The rod cover has a first end that faces the cylinder chamber in the axial direction and a second end that faces the outside of the air cylinder, and the through hole is between the first end and the second end. And penetrated
An annular channel that opens to the second end and communicates with the outside of the air cylinder is formed between the through hole and the rod on the second end side of the seal member in the through hole. And
The exhaust passage is connected to the annular passage, and an air supply port for supplying the exhaust air to the annular passage is opened.
An air cylinder characterized by that. The cylinder chamber is partitioned into a first chamber and a second chamber by the piston, and the rod cover is provided at an axial end of the cylinder chamber on the first chamber side,
The exhaust flow path is connected to the port established in the second chamber;
Along with the movement of the piston toward the second chamber, exhaust air discharged from the port is supplied to the annular flow path through the exhaust flow path.
The air cylinder according to claim 1, The foreign material adhering to the rod is prevented from entering the first end side into the through hole on the second end side of the air supply port in the annular channel, and at the same time, supplied to the annular channel. An annular wiper that allows the discharged air that has been discharged to flow to the second end side is provided in slidable contact with the rod,
The air cylinder according to claim 1 or 2, wherein the air cylinder is provided. The port opened in the second chamber is a supply / exhaust port, and a quick exhaust valve is connected to the port through a supply / exhaust flow path, and compressed air is supplied from a pneumatic pressure source to the quick exhaust valve. The supplied air supply passage and the exhaust passage are connected to be able to switch communication with the supply / exhaust passage,
The air cylinder according to claim 2. In the region where the annular flow path extends from the second end side to the opening of the second end with respect to the seal member, the diameter of the annular passage is increased to a substantially constant depth in the axial direction and the circumferential direction. Is formed with a substantially constant width by a gap between the portion and the rod,
The air supply port is opened in the enlarged diameter portion of the through hole.
The air cylinder according to any one of claims 1 to 4, wherein the air cylinder is provided. The axial end on the second chamber side in the cylinder chamber is closed by a head cover.
The air cylinder according to claim 2 or 4, wherein the air cylinder is provided.

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