JPH03234904A - Multistage type pneumatic cylinder - Google Patents

Abstract

PURPOSE:To obtain a stroke several times as large as that of a cylinder by providing a piston and a piston rod, also providing a movable cylinder possible to enter in/exist from a fixed cylinder in axial direction thereof from one end of the fixed cylinder, and making compressed air alternately enter in/exist from ports near both ends of the fixed cylinder. CONSTITUTION:There is a movable cylinder 2 inside a fixed cylinder 1, and there is a piston rod 3 connected to a piston 8 inside thereof. Compressed air gateway ports 4 and 5 are formed near the right end and the left end of the fixed cylinder 1, and a piston 6 is attached to the movable cylinder 2. When an air valve is adjusted so as to have air pressed into the air gateway port 4 and ejected from the air gateway port 5, the movable cylinder 2 is projected from the fixed cylinder 1, next the piston rod 3 is projected from the movable cylinder 2. When the air valve is adjusted, here, so as to have air pressed in from the air gateway port 5 and ejected from the air gateway port 4, a device returns to its original state. Thereby a stroke several times as large as that of a cylinder can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Fields of Application The present invention is applicable to a wide range of fields such as industrial machines, conveyance machines, automatic devices, and robots.

BACKGROUND ART Conventionally, in all kinds of machines including industrial machines, conveyance machines, automatic devices, and robots, so-called pneumatic cylinders operated by compressed air, which have a structure consisting of a cylinder, a piston, and a piston rod (hereinafter referred to as "rod"), are at the heart of the machinery. It is used. This type of pneumatic cylinder has the advantage of a simpler mechanism and faster operating speed than similar cylinders operated by hydraulic pressure or a motor.

However, in this type of pneumatic cylinder, a rod is connected to a piston that reciprocates inside the cylinder, and the rod reciprocates in the axial direction, and the tip of the rod reciprocates from one end of the cylinder to the outside of the cylinder. The distance the tip can move, that is, the stroke, cannot be longer than the length of the cylinder.

Therefore, when using a pneumatic cylinder, a space for installing the cylinder is always required, which is at least the length of the required stroke.

A modification of this drawback is called a rodless pneumatic cylinder. Rodless pneumatic cylinder is
This is a structure in which a protrusion protruding outward from the side of the cylinder is attached to the piston, and a seal or the like is attached to the protrusion to maintain the airtightness of the cylinder even when the protrusion moves along with the piston in the axial direction of the cylinder. In addition to the complicated structure, this also requires a cylinder with a length that is approximately the same as the distance that the protrusion can move, that is, the stroke.

A pneumatic cylinder consisting of a cylinder, a piston and a rod, in which another cylinder pre-installed within the cylinder moves in and out out of one end of the cylinder in its axial direction, in the same manner as the rod actuates. By making the rod move in and out from one end of the cylinder, it is possible to obtain a stroke nearly twice that of the first cylinder (hereinafter referred to as the fixed cylinder). Furthermore, if a multi-stage pneumatic cylinder is constructed in which second and third separate cylinders (hereinafter referred to as movable cylinders) are overlapped, it is possible to obtain a stroke several times the length of the fixed cylinder.

Even if the movable cylinder and rod can be pushed out of the fixed cylinder using pneumatic pressure, a method for reliably and quickly storing the movable cylinder and rod into the fixed cylinder is desired. Not traditionally provided.

Therefore, the installation location of the pneumatic cylinder is always considered a necessary waste and is currently neglected.

OBJECTS OF THE INVENTION The present invention provides a reliable structure in which the movable cylinder and rod are pneumatically actuated for both protrusion and storage in the multi-stage pneumatic cylinder.

Structure of the Invention and Disclosure Based on Drawings FIG. 1 is an explanatory side view of a multi-stage pneumatic cylinder of the present invention. Here, a two-stage pneumatic cylinder is shown, with a movable cylinder inside a fixed cylinder (1). (2) and the piston rod (3) are both shown in a stowed state.

In addition, in this explanation, when referring to the end of a cylinder or rod,
According to the figures, the end where the movable cylinder or rod has an inlet/outlet, ie, the rod side, is called the right end, and the other end, ie, the head side, is called the left end.

There is a movable cylinder (2) that can move in the axial direction inside a fixed cylinder (1) that ensures airtightness, and inside the movable cylinder (2) there is a piston rod (3).

Compressed air (hereinafter referred to as air) inlet/outlet holes (4) and (5) are provided near the left and right ends of the fixed cylinder (1), respectively.
is worn. The movable cylinder (2) has, near its left end, a piston (6) surrounding its outer circumference and capable of sliding in its axial direction on the inner surface of the fixed cylinder (1).
) is attached, so the movable cylinder (2)
It can be forced out of the fixed cylinder (1) by air. Further, near the right end of the inner surface of the fixed cylinder (1), there is a sliding stop (7) for the piston (6). The sliding stop (7) may have any shape.

Note that, similar to the positional relationship between the cylinder, piston, and air inlet/outlet hole in a conventional pneumatic cylinder, the air inlet/outlet hole (4) near the left end is always closer to the left end than the piston (6) in the state shown in Figure 1. The air inlet/outlet hole (5) near the right end must always be located on the right end side from the position of the piston (6) when stopped by the sliding stop (7).

Inside the movable cylinder (2), a piston rod (3) connected to a piston (8) operates. Air inlet/outlet holes (9) and (10) are bored near the left end and right end of the movable cylinder (2), respectively.

Note that the vicinity of the left end may be left open. In that case, it may not necessarily be necessary to drill the air inlet/outlet hole (9). Further, a sliding stop (11) of an arbitrary shape for the piston (8) is attached near the right end of the inner surface of the movable cylinder (2). Note that the air inlet/outlet hole (10) must be located on the right end side of the position of the piston (8) when it is stopped by the sliding stop (11).

As can be seen from the above, the structure of the movable cylinder (2) is substantially the same as that of the fixed cylinder (1).

In addition, in FIG. 1, fixed cylinders (1
) or the bottom of the left end of the movable cylinder (2), but unlike this method, a sliding stop may be provided separately, or the bottom of the movable cylinder (2) or the piston rod (3) You may also attach a tsuba to their right end to stop them at the entrance/exit hole.

Next, the operating situation of the multi-stage pneumatic cylinder of the present invention will be explained with reference to FIG.

Since Figure 2 is for explaining the operating situation, the drawing is as follows:
Although it is simplified from the case in Figure 1, Figure 2(a)'(
By keeping in mind that e) and FIG. 1 show the same state, the contents of FIG. 2 can be fully understood.

In FIG. 2(a), the movable cylinder (2) and the piston rod (3) are both housed within the fixed cylinder (1). In operation, first, air is forced into the air inlet/outlet hole (4), and the air valve (12) is adjusted so that the air can be ejected from the air inlet/outlet hole (5).
Transition to states b) and (c).

The state shown in FIG. 2(b) is a state in which only the movable cylinder (2) protrudes from the fixed cylinder (1), and the state shown in FIG. 2(C) is
The piston rod (3) is shown protruding from the movable cylinder (2).

This stroke is therefore nearly twice the length of the fixed cylinder (1). That is, in the case of fixed cylinders (1) of the same length, the pneumatic cylinder having the structure of the present invention has a stroke that is approximately twice that of the conventional pneumatic cylinder.

In addition, within the movable cylinder (2), the piston rod (3)
The air ejected from the movable cylinder (2) by being pushed out is ejected into the outside air from the air inlet/outlet holes (1, 0).

Next, from the state shown in Figure 2 (C), the piston rod (3)
When storing the movable cylinder (2) into the fixed cylinder (1), first pressurize air through the air inlet/outlet hole (5), and then set the air valve so that the air can be blown out through the air inlet/outlet hole (4). After adjusting (12), Fig. 2(d)
state. That is, the air entering through the air inlet/outlet hole (5) first pushes the piston (6) and closes the movable cylinder (2), but the positional relationship between the movable cylinder (2) and the piston rod (3) does not change. . Figure 2(d)
When the state is reached, air is forced into the movable cylinder (2) through the air inlet and outlet hole (10) at the right end of the movable cylinder (2) and from the air inlet and outlet hole (5) at the right end of the fixed cylinder (1). As a result, the piston (8) is pushed to the left, and the piston rod (3) moves into the movable cylinder (2).
The movable cylinder (2) is placed inside the fixed cylinder (1).
and piston rod (3) are stored in Figure 2 (e).
). The state shown in Fig. 2(e) is as shown in Fig. 2(e).
Since the condition is the same as in a), one cycle of the pneumatic cylinder has now been completed.

Note that the stroke length is for each piston (6) and (8).
The mounting of the piston slide stops (7) and (11) can be adjusted as desired depending on the position. In addition, the operating speed is determined by air pressure, air inlet/outlet holes (4), (5) (9), (10
) is adjusted by the shape and dimensions of the hole. Further, the number of air inlet/outlet holes (9), (10) of the movable cylinder (2) is not necessarily limited to one, and this number also affects the operating speed.

Furthermore, in FIG. 2, when air is forced into the air inlet/outlet hole (4), only the movable cylinder (2) first protrudes, and then the piston rod (3) protrudes.
Due to the difference in the ease of sliding between the piston (6) and the piston (8), the piston rod (3) may protrude first, then the movable cylinder (2), or both may protrude at the same time. .

When the fixed cylinder (1) and movable cylinder (2) are combined to create two or more movable cylinders (2), the above operations are also combined, resulting in a multi-stage type with a stroke several times that of the fixed cylinder (1). A pneumatic cylinder can be obtained. The stroke of a pneumatic cylinder with n movable cylinders (2) is equal to that of a fixed cylinder (1).
The length of the pneumatic cylinder is approximately n+1 times the length of the pneumatic cylinder, and the inventor has decided to refer to this pneumatic cylinder as an n+1 stage cylinder.

FIG. 3 shows the structure of a double-headed three-stage pneumatic cylinder as an example of application of the present invention in which a movable cylinder and a piston rod enter and exit from both ends of a fixed cylinder.

Air inlet/outlet hole (24) in the center of the fixed cylinder (21)
When more air is injected, two movable cylinders on the left and right (
22), (22'), (22a), (22a'') and the piston rods (23) (23') protrude, and the stroke thereof is approximately three times that of the fixed cylinder (21), and then The operation of the stationary cylinder (21) will be easily understood from the drawings, as when air is forced in through the air inlet/outlet holes (25), (25') near both ends of the fixed cylinder (21), the fixed cylinder (21) returns to its original state.

Effects of the Invention The multi-stage pneumatic cylinder according to the present invention, unlike the conventional single pneumatic cylinder, can obtain a stroke several times that of the cylinder, so it can greatly contribute to making the machine more compact.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a two-stage pneumatic cylinder structure according to the present invention, FIG. 2 is an explanatory diagram of its operation, and FIG. It is an explanatory view of a stepped cylinder. 1.21... Fixed cylinder 2.22.22', 22a, 22a' Movable cylinder 3.23.23'... Piston rod 4.24
...Air inlet/outlet hole 5.25.25'...Air inlet/outlet hole 6...
... Piston 7 ... Piston sliding stopper 8 ...
...Piston 9... Air inlet/outlet hole 10... Air inlet/outlet hole 2 11... Piston sliding stopper 12...
・・・・・・Air valve

Claims (1)

[Claims] 1. There is a fixed cylinder with holes near both ends for letting compressed air in and out, and a piston operated by air pressure between these holes, and the piston rod is inserted from one end of the fixed cylinder in its axial direction. In place of the piston rod of a pneumatic cylinder mechanism that moves in and out of the fixed cylinder, a movable cylinder that has substantially the same structure as a fixed cylinder, has a piston and a piston rod inside the cylinder, and can move in and out of the fixed cylinder in the axial direction from one end of the cylinder. A two-stage pneumatic cylinder with a stroke longer than the length of the fixed cylinder, which is operated by simply connecting it to a device that alternately allows compressed air to enter and exit only through the holes near both ends of the fixed cylinder. 2. A multi-stage pneumatic cylinder obtained by combining the fixed cylinder and movable cylinder of the two-stage pneumatic cylinder described in 1.