JP2003097515A - Cylinder device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To move a piston with deceleration on the way of a forward stroke and a backward stroke of the piston with the structure itself of the cylinder device without using the electric control from outside. SOLUTION: This cylinder device 10 has a cylinder tube 12, a piston 14, a first pressure chamber 20, a second pressure chamber 22, a first and a second main ports 24 and 26 for supplying and discharging the air, a first auxiliary port 28 and a second auxiliary port 30, a first auxiliary port closing part 29 and a second auxiliary port closing part 31, and a first communication passage 44 and a second communication passage 46. With this structure, when the piston 14 reaches a decelerating position in the backward movement, the first auxiliary port closing part 29 and the second auxiliary port closing part 31 close the first auxiliary port 28 and the second auxiliary port 30, and when the piston 14 reaches a high speed selecting position, the first communication passage 44 and the second communication passage 46 communicate the first pressure chamber 20 with the first auxiliary port 28 or the second pressure chamber 22 with the second auxiliary port 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder device having a cylinder tube and a piston slidably fitted therein.

[0002]

2. Description of the Related Art Conventionally, a cylinder device having a cylinder tube and a piston slidably fitted therein is widely used in various fields and applications. By the way, for example, when this cylinder device is applied to a lifting device for an article, the piston is raised at a constant speed so that the support portion provided on the piston rod receives the article from the receiving portion during the stroke and supports it to lift it. However, if the moving speed of the piston is high, the support part will violently collide with the article during the stroke, resulting in collapse of the article, displacement of the article, or damage to the article. Cause

Similarly, when the piston is lowered rapidly at a constant speed while the article is placed on the support, and the article is delivered to the delivery section below, the same problem occurs. That is,
If the piston is moved down rapidly at a constant speed, the article will vigorously hit the delivery section below, causing problems such as collapse of the load, displacement of the article, and damage to the article.

On the other hand, if the piston is slowly moved up and down at a constant speed in order to avoid this, the above problem can be avoided, but in this case, the time required for the reciprocating motion of the piston becomes long and the efficiency is lowered. Therefore, in an elevating device using this type of cylinder device, at the time of ascending or descending movement, that is, when the piston moves forward or backward, the piston is initially moved at a high speed, and the moving speed of the piston is lowered in the middle. That is, it is desirable that the moving speed of the piston is decelerated and then the moving speed of the piston is switched to the high speed again.

With this configuration, the operation of receiving the article at the receiving portion and raising it or lowering it from the raised position to deliver the article to the delivery portion can be performed with high efficiency,
In addition, it is possible to prevent the articles from being collapsed, displaced, and damaged.

As means for achieving this, a position sensor (proximity sensor, etc.) for detecting the moving position (stroke position) of the piston is provided, and the supply / discharge or distribution of the working fluid is controlled based on the detection signal from the position sensor. It is conceivable that a large number of switching valves are electrically controlled by the control unit.

However, in this case, a position sensor, a large number of switching valves, a plurality of control circuits, etc. are required, and the total number of parts is increased, and the structure of the apparatus becomes complicated, resulting in a significant cost increase. . Furthermore, it is necessary to install and install a position sensor and electric wiring, which complicates the work for installing the device, causes a malfunction of the sensor and the like, and also complicates the work for maintenance. Occurs.

Although the case where the cylinder device is applied to the lifting device has been described as an example, the same problem occurs when the cylinder device is applied to other uses.

[0009]

The cylinder device of the present invention has been devised to solve such problems. Thus, the first aspect of the present invention is a cylinder device having a cylinder tube and a piston slidably fitted in the cylinder tube, wherein at least either forward movement or backward movement of the piston is performed. The moving speed of the piston is switched from a relatively high speed to a low speed, and further from the low speed to the high speed by the structure itself of the cylinder tube and the piston, irrespective of electrical control from the outside. To do.

According to a second aspect of the present invention, (a) a cylinder tube, (b) a piston slidably fitted in the cylinder tube, and (c) the cylinder tube defined by the piston. A first pressure chamber and a second pressure chamber therein, and (d) a state of communicating with the front end portion and the rear end portion of the cylinder tube in the forward direction of the piston and with the first pressure chamber and the second pressure chamber, respectively. And the first and second main ports for supplying and discharging the fluid, and (e) the first main port.
A first sub-port that is provided so as to penetrate the cylinder tube at a position separated from the main port in the backward direction of the piston by a predetermined distance, and that supplies or discharges fluid to or from the first pressure chamber; Move integrally with the piston,
During the movement of the piston, from the time the piston reaches the deceleration position to immediately before the high speed switching position, a first sub-port closing portion that closes the first sub-port, and (g) integrally moves with the piston, It has a first communication passage that connects the first pressure chamber and the first sub-port until the piston reaches the high speed switching position or immediately before the deceleration position. .

According to a third aspect of the present invention, (a) a cylinder tube, (b) a piston slidably fitted in the cylinder tube, and (c) the cylinder tube defined by the piston. A first pressure chamber and a second pressure chamber therein, and (d) a state of communicating with the front end portion and the rear end portion of the cylinder tube in the forward direction of the piston and with the first pressure chamber and the second pressure chamber, respectively. The first and second main ports for supplying and discharging the fluid, and (e) the second main port.
A second auxiliary port that penetrates through the cylinder tube at a position separated from the main port in the forward direction of the piston by a predetermined distance and supplies or discharges a fluid to or from the second pressure chamber; Move integrally with the piston,
During the movement of the piston, the second sub-port closing portion that closes the second sub-port during the period from when the piston reaches the deceleration position to immediately before the high speed switching position; and (g) integrally moves with the piston, A second communication passage that connects the second pressure chamber and the second auxiliary port is provided when the piston reaches the high-speed switching position or immediately before the deceleration position. .

According to a fourth aspect of the present invention, in any one of the first to third aspects, the cylinder device includes a piston rod and an article support portion provided on the piston rod.
It is characterized in that it is configured as an elevating device that elevates and lowers the article in the support portion.

[0013]

As described above, according to the first aspect of the present invention, in at least one of the forward movement and the backward movement of the piston, the moving speed of the piston changes from a relatively high speed to a low speed, and further from a low speed to a high speed. According to the present invention, the cylinder device itself has a function of decelerating in the middle of the stroke of the piston movement, because the cylinder device itself is structurally provided with the function of switching without being electrically controlled from the outside. Therefore, in order to realize this, it is possible to omit or reduce the position sensor that detects the stroke position of the piston, a large number of switching valves, etc., and it is possible to simplify the overall device configuration and install the device. It can be easily performed and the maintenance work thereafter can be simplified.

The cylinder device of the present invention is suitable for application to an elevating device (claim 4), and in this case, when the article is received and raised in the middle of the forward stroke by the forward movement of the piston, or when the article is raised from the raised position. When the article is delivered while being lowered and the piston is in the middle of the backward stroke, the article can be received or delivered without giving an impact to the article, and the lifting operation as a whole can be performed efficiently in a short time.

According to a second aspect of the present invention, the cylinder tube is provided with the first sub-port, and the first sub-port is closed during the movement of the piston from the time the piston reaches the deceleration position to the time immediately before the high speed switching position. And a first communication passage that connects the first pressure chamber and the first sub port until the piston reaches the high speed switching position or immediately before the deceleration position. If you do like this,
By moving the piston, the moving speed can be automatically switched from relatively high speed to low speed, and further from low speed to high speed.

On the other hand, according to the third aspect of the present invention, while the second auxiliary port is provided on the second main port side of the cylinder tube,
It moves integrally with the piston, and during the movement of the piston, from the time the piston reaches the deceleration position to immediately before the high speed switching position, the second
A second sub-port closing portion that closes the sub-port and a second communication passage that allows the second pressure chamber and the second sub-port to communicate with each other until the piston reaches the high-speed switching position or immediately before the deceleration position. In this case, the moving speed of the piston can be switched by moving the piston itself. It is also possible to combine claim 2 and claim 3 to switch the moving speed of the piston from a relatively high speed to a low speed, and further from a low speed to a high speed by moving the piston itself.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. In FIG. 1, reference numeral 10 denotes a cylinder device of this embodiment, which includes a cylinder tube 12, a piston 14 slidably fitted in the cylinder tube 12, and a piston rod 16 extending from the piston 14. Piston rod 16
The article is provided with a support portion 18 for articles.
In FIG. 8, an article 62 to be described later is supported and can be moved upward or downward.

Here, the inside of the cylinder tube 12 is divided by the piston 14 into a first pressure chamber 20 and a second pressure chamber 22. In this example, the upward movement of the piston 14 is forward movement and the downward movement is backward movement.

The cylinder tube 12 has a piston 14
In the forward direction, the first main port 2 is connected to the front end of the first pressure chamber 20 and the rear end of the second pressure chamber 22, respectively.
4 and the second main port 26 are provided so as to penetrate the cylinder tube 12, and the first main port 24,
Air as a working fluid is supplied to or discharged from the first pressure chamber 20 or the second pressure chamber 22 through the second main port 26.

The cylinder tube 12 also has a first sub port 28 and a second sub port 30 at positions separated from the first main port 24 and the second main port 26 by a predetermined distance in the backward and forward directions of the piston 14. Are provided so as to penetrate the cylinder tube 12. These first
The sub port 28 and the second sub port 30 are also the first pressure chamber 2
It is for supplying or discharging air to the zero or second pressure chamber 22.

These four ports, namely the first main port 2
4, the second main port 26, the first sub-port 28 and the second sub-port 30 to the flow path 3 for supplying or discharging air
2, 34, 36, 38 are connected to each other, and a throttle valve 40 and a check valve 42 are provided in parallel in each of the flow paths 32, 34, 36, 38. The check valves 42 are provided so as to open when air is supplied and close when air is discharged.

In this embodiment, the piston 14 has a first sub-port closing portion 29 which closes the first sub-port 28 during the forward movement of the piston 14 from immediately after the piston 14 reaches the deceleration position to immediately before the high speed switching position. Also, during the backward movement of the piston 14, the second sub port closing portion 31 that closes the second sub port 30 is provided between the front end portion and the rear end portion of the piston 14 from the time the piston 14 reaches the deceleration position to the time immediately before the high speed switching position. It is formed integrally with.

Furthermore, when the piston 14 moves forward, when the piston 14 reaches the high speed switching position, the first communication passage 44 for communicating the first pressure chamber 20 and the first sub port 28 with each other.
Also, when the piston 14 moves backward, when the piston 14 reaches the high speed switching position, the second communication passages 46 that communicate the second pressure chamber 22 and the second auxiliary port 30 partially penetrate the piston 14. It is provided in the form.

The first communication passage 44 has an end face opening 48 that opens at the end face of the piston 14 on the first pressure chamber 20 side, and an opening at the outer peripheral face of the piston 14 at a position separated from the end face by a predetermined distance in the backward direction of the piston 14. Peripheral opening 5
0 and a passage 52 connecting them.

Here, the peripheral opening 50 has an annular shape,
The passage 5 is connected to the annular peripheral opening 50.
2 and end face openings 48 are provided at two or more positions in the circumferential direction.

On the other hand, the second communication passage 46 has an end face opening 54 that opens at the end face of the piston 14 on the second pressure chamber 22 side.
And a peripheral surface opening 56 that opens at the outer peripheral surface of the piston 14 at a position separated from the piston 14 in the forward direction by a predetermined distance, and a passage 58 that connects them.

The peripheral surface opening 5 is also formed in the second communication passage 46.
6 has an annular shape, and a passage 58 and an end face opening 54 are provided so as to communicate with the peripheral face opening 56 at two or more circumferential positions.

Here, the first communication passage 44 and the first sub port 28
And have the following positional relationship. That is, in FIG.
As shown in (I), when the piston 14 reaches the predetermined deceleration position during the forward movement of the piston 14, the first sub port 28 is closed by the first sub port closing portion 29, and As shown in III), when the piston 14 reaches the high speed switching position, the first communication passage 44
So that the peripheral surface opening 50 communicates with the first sub port 28.
The positional relationship between them is defined.

On the other hand, the second communication passage 46 and the second sub port 3
As shown in FIG. 3 (II), when the piston 14 reaches the predetermined deceleration position when the piston 14 moves backward, the second sub-port 30 moves to the second position
When the piston 14 is closed by the sub port closing portion 31 and the piston 14 reaches the high-speed switching position as shown in FIG. 3 (III), the peripheral surface opening 56 in the second communication passage 46 becomes the second opening.
The positional relationship between them is defined so as to communicate with the sub port 30.

In both the first communication passage 44 and the second communication passage 46, the diameters of the peripheral surface openings 50, 56 are relatively large with respect to the passages 52, 58. That is, these peripheral surface openings 5
The dimensions 0 and 56 are formed to be larger in the moving direction of the piston 14 than the inner diameters of the passages 52 and 58, respectively.

Next, the operation of the cylinder device 10 of this embodiment will be described with reference to FIG.
And it demonstrates below based on FIG. FIG. 2 (I) shows a state in which the piston 14 is located at the retracted end, and when air is supplied through the flow path 34 in this state, the supplied air is supplied with the second pressure through the second main port 26. It flows into the chamber 22. Furthermore, air is supplied to the second pressure chamber 22 through the second sub port 30 and the second communication passage 46 through the flow path 38.

At this time, the first pressure chamber 20 on the side opposite to the second pressure chamber 22 has the first main port 24 and the first sub port 2
Since it is opened to the flow paths 32 and 36 through 8, the piston 14 starts to move forward at high speed when air is supplied to the second pressure chamber 22 through the two ports 26 and 30.

Next, the piston 14 which has moved forward is moved to the position shown in FIG.
When the position shown in I), that is, the deceleration position is reached, the first sub-port 28 is closed by the first sub-port closing portion 29 here, and the air in the first pressure chamber 20 is the first main port 24.
It will be discharged to the outside only through. That is, the air in the first pressure chamber 20 cannot be discharged to the outside through the first sub-port 28, whereby the piston 14 moves forward at a relatively lower speed.

The first main port 2 of the flow paths 32 and 36
The speed at the time of deceleration can be easily changed and adjusted by adjusting the flow rate of the throttle valve 40 on the side of the flow path 32 connected to No. 4 to a small amount.

After that, as shown in FIG. 2 (III), when the piston 14 reaches the high speed switching position, the peripheral surface opening 50 in the first communication passage 44 comes into alignment with the first sub port 28, Here, the air in the first pressure chamber 20 can be again discharged to the outside through both the first main port 24 and the first sub port 28. Therefore, the piston 14
Starts moving forward again at a relatively high speed. This state continues until the piston 14 reaches the forward end. That is, the piston 14 then moves forward at a relatively high speed until it reaches the forward end shown in FIG.

FIG. 3 shows the operation when the piston 14 is retracted. FIG. 3 (I) shows a state in which the piston 14 is located at the forward end, and at this time, the first pressure chamber 20 passes through the first main port 24 and the first sub port 28 to form the flow paths 32 and 3.
6, the second pressure chamber 22 on the opposite side is also open and the second main port 26 and the second auxiliary port 30
Through to the flow paths 34 and 38, respectively.

Therefore, when air is supplied to the first pressure chamber 20 through the flow passages 32 and 36, the piston 14 causes the air in the second pressure chamber 22 to flow through the second main port 26 and the second sub port 30.
It moves backward relatively at high speed while being discharged to the outside through. Then, as shown in FIG. 3 (II), the piston 1
When 4 reaches the deceleration start position, the second sub port 30 is closed by the second sub port closing portion 31 here, and the air in the second pressure chamber 22 can be discharged only through the second main port 26. Becomes As a result, the backward movement speed of the piston 14 is reduced.

Then, as shown in FIG. 3 (III), when the piston 14 reaches the high speed switching position again, the second communication passage 46 connects the second pressure chamber 22 and the second auxiliary port 30 there. Then, the air in the second pressure chamber 22 can be discharged to the outside through the two ports 26 and 30. As a result, the retreat speed of the piston 14 returns to high speed, and the piston 14 moves at high speed until reaching the retreat end shown in FIG. 3 (IV).

In this example, the cylinder device 10 having the above-described structure constitutes an elevating device as shown in FIGS. 2 and 3, and the piston 14 as shown in FIG. 2 (I). The article 62 receives the article 62 from the receiving section 60 by the forward movement of the and moves the article 62 up.

At this time, in the process of approaching the article 62, the cylinder device 10 advances the piston 14 at a high speed to bring the support portion 18 closer to the article 62, and as shown in FIG. The piston 14 starts decelerating when the object approaches the article 62, and the support portion 18 softly contacts the article 62 in the decelerated movement state, and the article 62 is lifted by the subsequent forward movement of the piston 14. After that, the piston 14 is switched to the high speed movement again, and the article 6
2 is lifted up to a predetermined position at a high speed.

On the other hand, as shown in FIG. 3, when the article 62 in the raised position is delivered to the delivery section 64,
As shown in (I), the piston 14 initially moves backward (moves downward) at a high speed, and when the article 62 approaches the transfer section 64, the piston 14 moves backward as shown in FIG. 3 (II). The movement is switched to the deceleration movement, and the article 62
Is gently delivered to the delivery unit 64. Then piston 1
4 again switches to high speed movement, and moves to the retracted position at high speed.

FIG. 4 shows the cylinder device 10 with a conveyor 66.
The article 62 carried by the conveyor 66 is received from the conveyor 66 and raised, or the article 62 is lowered to convey the article 66.
It shows an example when applied as an elevating device to deliver to and from. In this case as well, the cylinder device 10 uses the article 6
2 can be softly received and lifted from the conveyor 66 without impact, or the article 14 can be softly transferred to the conveyor 66 by lowering the piston 14.

As described above, according to this example, the moving speed of the piston 14 can be reduced during the stroke by the structure of the cylinder device 10 itself without relying on electrical control from the outside. A position sensor for detecting the stroke position of the piston 14 and a large number of switching valves can be omitted or saved as in the case of electrically controlling the movement, and the entire configuration of the device can be simplified and the installation of the device can be facilitated. Not only can it be performed easily, but the maintenance work thereafter can be simplified.

When the cylinder device 10 is applied to an elevating device, the article 62 can be softly received and raised from the receiving section 60, and the article 62 can be softly transferred to the delivery section 64 when moving downward. Can be handed over. In addition, the entire lifting operation can be performed at a high speed, and the articles 62 can be received or delivered with high efficiency.

Although the embodiment of the present invention has been described in detail above, this is merely an example. For example, in the above example, the piston 14 is decelerated in the middle of the stroke in both forward and backward movements, but in some cases, as shown in FIG. It is possible to provide only the port 28 and the first communication passage 44 so as to decelerate during the stroke only when the piston 14 moves upward, or alternatively, as shown in FIG. And piston 14
And only the second auxiliary port 30 and the second communication passage 46 are provided in
It is also possible to decelerate during the stroke only when the piston 14 moves downward.

The above example is an example of the meter-out system in which the moving speed of the piston 14 is controlled by controlling the flow on the air discharge side. The piston 14 is controlled by controlling the flow on the air supply side. It is also possible to control the moving speed of the piston 14, that is, to control the moving speed of the piston 14 by a meter-in method.

For example, as shown in FIG. 2 (IV), by changing the direction of the check valve 42, the moving speed of the piston 14 when the piston 14 moves backward from the state of being located at the forward end is changed. It can be controlled by the meter-in method.
In this case, in the state shown in FIG. 2 (IV), the first main port 24
Since the first sub port 28 and the first sub port 28 are in communication with the first pressure chamber 20, air can be supplied to the first pressure chamber 20 through the two ports 24, 28. Therefore, the piston 14 starts moving backward at a high speed downward in FIG.

At this time, the first communication passage 44 is connected to the piston 14
2 (III), that is, until the deceleration start position is reached, the first pressure chamber 20 and the first sub port 28 are in communication with each other. Therefore, until this state is reached, the piston 14
Moves backward at high speed, that is, moves downward in FIG. When the piston 14 is in the state of closing the first sub port 28 at the first sub port closing portion 29, the air can be supplied to the first pressure chamber 20 only through the first main port 24, whereby the piston 14 can be supplied. The backward movement speed of 14 is reduced.

Then, the decelerating movement of the piston 14 is continued until the state shown in FIG.
When the vehicle further moves backward from the position shown in (II), that is, when the high-speed switching position is reached, the first main port 24 and the first sub-port 28 are again in communication with the first pressure chamber 20. Air is supplied to the first pressure chamber 20 through the two ports 24 and 28, and then the piston 14 moves backward again at high speed to reach the backward end shown in FIG. 2 (I).

On the other hand, in the meter-in system, the piston 14
When moving forward, the movement is as follows. That is, FIG.
As shown in (IV), when the piston 14 is located at the retracted end, the second main port 26 with respect to the second pressure chamber 22.
Air is supplied to the second pressure chamber 22 through the second sub port 30, and therefore the piston 14 moves forward at a high speed from the retracted end, that is, moves upward in FIG.

The high speed movement of the piston 14 is shown in FIG.
When the second auxiliary port closing portion 31 of the piston 14 closes the second auxiliary port 30, the air is supplied to the second pressure chamber 22 only through the second main port 26. Then, the piston 14 starts decelerating. This deceleration movement continues until the state shown in FIG.
When it moves further than the position shown in (II), the second pressure chamber 22 again becomes in the state of communicating with the second main port 26 and the second sub port 30 through the two ports 26, 30. Air is supplied to the second pressure chamber 22, which causes the piston 14 to move forward again at high speed,
The high speed movement is continued until the forward end shown in FIG.

FIG. 6 shows another embodiment of the present invention.
In this example, the ring-shaped first sub port closing portion 68 and the second
The sub-port closing portion 70 is provided on each of the advancing side and the retreating side of the piston 14, so that the sub-port closing portion 68 and the piston 14 are provided between the first sub-port closing portion 68 and the piston 14. Forming openings 72 and 74, and also a first
A first communication passage 76 that communicates the pressure chamber 20 with the opening 72 and a second communication passage 78 that communicates the second pressure chamber 22 with the opening 74 are formed.

Even in this case, as shown in FIGS. 7 and 8, the moving speed of the piston 14 is switched from the high speed to the decelerating movement, and further from the decelerating movement to the high speed, as described above. be able to.

Furthermore, as also shown in FIG.
Also, in the embodiment shown in FIG. 8, the speed can be switched only when the piston 14 moves forward or only when it moves backward.

The first embodiment (FIGS. 1 to 3 and 5)
The peripheral opening 50 provided in the piston 14 in FIG.
, The end face opening 48 and the passage 52 are provided at one position in the circumferential direction so as to communicate with the peripheral face opening 50, or the piston 14 and the piston rod. When the rotation direction of 16 is positioned, as shown in FIG. 11, the circumferential surface opening 50 is also provided only at any one position in the circumferential direction, specifically, on the side where the first sub port 28 is provided. It is also possible to provide only. This point is piston 14
The same applies to the second communication passage 46 at the rear end portion.

In the above example, the cylinder device 10 is replaced by the article 62.
However, the cylinder device of the present invention can be applied to various other uses. For example, the present invention has various modifications without departing from the scope of the invention. It can be configured with.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a cylinder device that is an embodiment of the present invention.

FIG. 2 is an operation explanatory view when the piston moves forward in the cylinder device of the embodiment.

FIG. 3 is an explanatory view of the action when the piston moves backward in the cylinder device of the embodiment.

FIG. 4 is a diagram showing an example in which the cylinder device of FIGS. 1 to 3 is applied to an elevating device for exchanging articles with a conveyor.

FIG. 5 is a diagram showing another example of the cylinder device of the present invention.

FIG. 6 is a view showing another embodiment of the piston in the cylinder device of the present invention.

FIG. 7 is an operation explanatory view when the piston shown in FIG. 6 moves forward.

FIG. 8 is an explanatory view of the action when the piston shown in FIG. 6 moves backward.

FIG. 9 is a diagram showing still another example of the cylinder device of the present invention.

FIG. 10 is a view showing still another embodiment of the piston in the cylinder device of the present invention.

FIG. 11 is a view showing still another embodiment of the piston in the cylinder device of the present invention.

[Explanation of symbols]

10 cylinder device 12 cylinder tube 14 pistons 16 piston rod 18 Support 20 First pressure chamber 22 Second pressure chamber 24 1st main port 26 Second Main Port 28 First Vice Port 29,68 1st sub port closing part 30 Second vice port 31,70 Second vice port closing part 44,76 First communication passage 46,78 Second communication passage 62 articles

Claims (4)

[Claims] 1. A cylinder device having a cylinder tube and a piston slidably fitted in the cylinder tube, wherein an electric power from an external source is used in at least either forward movement or backward movement of the piston. A cylinder device characterized in that the moving speed of the piston is switched from a relatively high speed to a low speed, and further from the low speed to the high speed by the structure itself of the cylinder tube and the piston irrespective of physical control. 2. A cylinder tube; (b) a piston slidably fitted in the cylinder tube; and (c) a first pressure chamber in the cylinder tube defined by the piston. (2) Fluid supply provided in the second pressure chamber and (d) in the forward direction of the piston, at the front end portion and the rear end portion of the cylinder tube and in communication with the first pressure chamber and the second pressure chamber, respectively.・
Ejection first and second main ports and (e) penetrating the cylinder tube at a position separated from the first main port by a predetermined distance in the backward direction of the piston, and provided in the first pressure chamber. On the other hand, the first sub port for supplying or discharging the fluid and (f) the piston moves integrally with the piston, and during the movement of the piston, the first sub port is provided immediately before the high speed switching position until the piston reaches the deceleration position. The first sub-port closing portion that closes the port and (g) the piston moves integrally with the piston, and when the piston reaches the high speed switching position or immediately before the deceleration position, the first pressure chamber and the first pressure chamber A cylinder device having a first communication passage communicating with the first sub-port. 3. A cylinder tube; (b) a piston slidably fitted in the cylinder tube; and (c) a first pressure chamber in the cylinder tube, which is defined by the piston. (2) Fluid supply provided in the second pressure chamber and (d) in the forward direction of the piston, at the front end portion and the rear end portion of the cylinder tube and in communication with the first pressure chamber and the second pressure chamber, respectively.・
Ejection first and second main ports and (e) Penetration through the cylinder tube at a position separated from the second main port by a predetermined distance in the forward direction of the piston, and provided in the second pressure chamber. On the other hand, the second sub port for supplying or discharging the fluid and (f) the piston moves integrally with the piston, and during the movement of the piston, from the time when the piston reaches the deceleration position to immediately before the high speed switching position, the second sub port. A second sub-port closing portion that closes the port and (g) the piston and the second pressure chamber and the second pressure chamber that move integrally with the piston until the piston reaches the high-speed switching position or immediately before the deceleration position. A cylinder device having a second communication passage that communicates with two sub-ports. 4. The elevating device according to claim 1, wherein the cylinder device includes a piston rod and an article supporting portion provided on the piston rod, and the article elevates and lowers at the supporting portion. A cylinder device characterized by being configured as.