JPH049923B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an air cylinder device used for shifting a transmission of a vehicle, etc.
In particular, the present invention relates to an air cylinder device in which a piston rod can be stopped at three positions, and is capable of lubricating the seal members of sliding parts by supplying oil to them.

Prior Art In FIG. 2, a conventional air cylinder device 1
has a pair of first and second outer pistons 3, 4 within the cylinder 2 and slidable relative to the cylinder.
, an inner piston 5 that is slidable relative to the outer piston, and a piston rod 6 that is fixed to the inner piston. A second airport P ₁ and a second airport P ₂ are provided. A ring-shaped stopper 8 is fixed to the axial center of the inner circumferential surface 2C of the cylinder 2.
The rightward movement of the second outer piston 3 or the leftward movement of the second outer piston 4 is restricted by the stopper. A breathing hole 9 opened on both sides of the stopper 8 and a space 10a inside the breathing hole and the outside of the cylinder 2, for example inside the case 10.
A breather hole 11 communicating with the cylinder wall 2d was provided in the cylinder wall 2d. Further, the upper part of the breathing hole 9 was closed with a lid 12.

In the air cylinder device 1, a second air port is connected to the first air port _P1 as shown by arrows A and B.
When air is sucked into P ₂ as shown by arrows C and D,
The outer pistons 3 and 4 can each move to the leftmost position or rightmost position shown by imaginary lines, or to the neutral position shown by solid lines, and the inner piston 5 can also move to three points accordingly and move to the respective positions. Stop at.
In this case, when the outer pistons 3, 4 move from side to side, a vacuum or high pressure condition naturally occurs within the cylinder 2. Air flows in or out through the breather holes 9 and 11 as shown by arrows E and F, and air is breathed out.

However, in the conventional example, the seal member S (for example, O
Since oil was not supplied to the sealing members S between the outer pistons 3 and 4 and the cylinder 2, there was a drawback that these sealing members S wore out prematurely. As a result, airtightness deteriorates, resulting in a disadvantage that an appropriate output from the air cylinder device 1 cannot be obtained.

Furthermore, Japanese Patent Application Laid-Open No. 51-101224 discloses a spool operating device, but the conventional example has a cylinder body with a stopper protruding from the center of the inner wall, and a cylinder that slides into the cylinder body on both sides of the stopper. Consisting of a pair of cylindrical outer pistons that are freely fitted together, an inner piston that is slidably fitted into the pair of outer pistons, and a piston rod that is integral with the inner piston and penetrates the end wall of the cylinder body, A double piston cylinder device in which an engaging protrusion is formed on the outer end of each cylindrical outer piston to engage with each end surface of the inner piston, and although it shares the basic structure with the present invention, Although the technology is similar to the conventional example described above, it does not disclose any lubrication mechanism for the seal member disposed on the outer periphery of the piston, and therefore the present invention has no purpose, structure, or effect. This is a different and different invention.

Furthermore, Japanese Utility Model Application No. 50-125691 discloses a lubricating device for a pneumatic equipment cylinder, but in this conventional example, the piston rod is made hollow and an oil passage is provided here to guide oil to the outer circumference of the piston. Although it is designed to lubricate the piston seal, a grease nipple is provided at one end of the piston rod, and grease is injected from the grease nipple to lubricate the outer circumference of the piston, so it is necessary to periodically lubricate the outer circumference of the piston. Grease must be supplied;
This is troublesome, and if the supply of grease is neglected, there is a risk of running out of lubricating oil. It was also inconvenient in that it was impossible to use anything other than grease for lubrication.

Furthermore, Japanese Utility Model Application No. 56-117102 discloses an air cylinder equipped with a packing lubrication function, but in this conventional example, an oil passage is provided that axially passes through the inside of the piston rod from the outer circumference of the piston. , lubricating oil is supplied between the piston and the inner wall of the cylinder through the oil passage, but the oil is supplied from the outside, and the oil is stored in a case integrated with the cylinder. The structure is completely different from that of the present invention in which a chamber is provided.

Problems to be Solved by the Invention The present invention has been made to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to provide an oil storage chamber in a case integrated with the cylinder, By providing an oil passage that axially penetrates the inside of the piston rod from the outer circumference and communicates with the oil storage chamber, it is possible to supply oil to each seal member and lubricate them. Accordingly, it is an object of the present invention to improve the durability of the seal member, prevent deterioration of airtightness, and stably obtain an appropriate output from the air cylinder device over a long period of time.

Means for Solving the Problems In short, the present invention provides a pair of outer pistons that are slidable relative to the cylinder and a pair of inner pistons that are slidable relative to the outer piston within a cylinder.
In an air cylinder device in which a piston rod fixed to the inner piston is housed, an oil storage chamber is provided in a case integrated with the cylinder,
An oil passage is provided that axially penetrates the inside of the piston rod from the outer circumference of the inner piston and communicates with the oil reservoir, and the oil stored in the oil reservoir is passed through the oil passage of the piston rod and connected to the inner piston. The present invention is characterized in that it is configured to supply lubrication to a seal member between the outer pistons and a seal member between the outer pistons and the cylinder.

The present invention will be explained below based on embodiments shown in the drawings. The air cylinder device 21 according to the present invention has a second
Since there are many parts in common with the conventional air cylinder device 1 shown in the figure, the same parts are given the same reference numerals as in FIG. 1 and their explanation will be omitted. Inside the cylinder 2, there are a pair of outer pistons 3 and 4 which are slidable relative to the cylinder, an inner piston 15 which is slidable relative to the outer piston, and a piston rod 16 fixed to the inner piston. It is accommodated.
The cylinder 2 is fixed to a case 10 by bolts 18, and an oil storage chamber 19 is provided in the case, and an oil level 20 is provided in the oil storage chamber.
The oil 20 is contained so that a reaches near the center of the piston rod 16.

The inner piston 15 is provided with an oil passage 15a in the radial direction, and an oil passage 16a is provided axially passing through the inside of the piston rod 16. They communicate with each other through oil passages 16b in both directions.

Air pipes _{22 ,}
23 is connected, and the air pipe 23 passes through the oil 20 and is connected to an external air supply source.

The present invention is configured as described above, and its operation will be explained below. In the oil storage chamber 19 in the case 10, the oil level 20a has reached the oil passage 16a of the piston rod 16, so the oil 20 flows into the oil passage.
The oil flows downward from the oil passage 16b, flows into the oil passage 15a of the inner piston 15, enters the sliding surfaces of the inner piston and the outer pistons 3 and 4, lubricates the seal member S, and also flows from around the stopper 8. Outer pistons 3, 4 and inner peripheral surface 2 of cylinder 2
It also enters between the seal member S and lubricates the seal member S.
And the pressure head of oil 20 is inside piston 1
5 and extends to about 1/2 of the diameter of the outer piston 15, so up to this point it will be naturally lubricated, and above this point each piston 3, 4,
The oil 20 rises according to the movement of the seal member 15 or due to capillary action, and the upper seal member S is evenly lubricated, thereby improving the durability of the seal member S.

Note that other functions are the same as those of the conventional example shown in FIG. 1, so explanations will be omitted.

Effects of the Invention Since the present invention is configured and operates as described above, an oil storage chamber is provided in the case integrated with the cylinder, and the oil is passed through the piston rod from the outer circumference of the inner piston in the axial direction. Since an oil passage communicating with the reservoir chamber is provided, oil can be supplied to each sealing member of the piston to lubricate them. As a result, the durability of the sealing member can be improved and the reduction in airtightness can be prevented. This has the effect that an appropriate output of the air cylinder device can be stably obtained over a long period of time by preventing this.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view of an air cylinder device according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view of an air cylinder device according to a conventional example. 2 is a cylinder, 3 and 4 are outer pistons, 10 is a case, 15 is an inner piston, 15a, 16a,
16b is an oil passage, 16 is a piston rod, 1
9 is an oil storage chamber, 20 is oil, 21 is an air cylinder device, and S is a sealing member.

Claims (1)

[Claims] 1. An air cylinder in which a pair of outer pistons that are slidable relative to the cylinder, an inner piston that is slidable relative to the outer piston, and a piston rod that is fixed to the inner piston are accommodated in the cylinder. In the apparatus, an oil storage chamber is provided in a case integrated with the cylinder, an oil passage is provided that axially passes through the inside of the piston rod from the outer circumference of the inner piston and communicates with the oil storage chamber, and the oil storage chamber The oil stored in the piston rod is supplied to the seal member between the inner piston and the outer piston and the seal member between the outer piston and the cylinder through the oil passage of the piston rod to lubricate the seal members. Air cylinder device.