JPS6262006A - Multi-stage type actuator - Google Patents

Abstract

PURPOSE:To enable both generation of long stroke within a small space and easy manufacture of each of piston/cylinders constituted in multi stages by forming fluid flow bypasses communicating the internal and external parts to each other inside the small-diameter parts of said cylinders. CONSTITUTION:To elongate each of cylinders, fluid is first fed into them from a piping 51 which is connected to a cylinder tube 15. Fluid then have a primary piston/cylinder 30 elongated to the right and some of the fluid flows into a chamber III through a hole 10. The fluid then has a secondary piston/cylinder 35 elongated to the right and some of the fluid flows into a chamber V through a hole 11, thereby elongating a piston 37. At this time, fluid staggered in a chamber VI is forced to run into a chamber IV through a bypass passage 41. Fluid staggered in the chamber IV then flows into a chamber II through a bypass passage 42 when the piston 37 is distorted. Finally, the fluid flows out from the chamber II via a piping 52.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a multi-stage actuator that can be applied to various lifting power devices and can provide a large stroke in a small space.

Conventional multi-stage actuators of this type have a limited stroke length to some extent because as the number of stages increases, the number of pipes guiding the fluid increases and becomes complex, and the length of the pipes also increases, making it impractical. There are drawbacks such as:

Furthermore, when a cylinder or the like is operated by a multistage actuator as shown in FIG. 1, the inside of the cylinder is separated into chamber 1 and chamber A structure is adopted in which the piston 2 and the rod are separated into a chamber (1) and a chamber (2). 10 indicates a hole bored in the center of the piston 1.

Therefore, when each piston 1, 2 is extended, first, when fluid flows into the I chamber from the A pipe 11, the fluid that flows into the I chamber passes through the center hole 10 and also flows into the be done. Therefore, the pistons 1, 2 will expand. At this time, the fluids in chambers (1) and (2) are discharged from the B pipe 12 and the expandable C pipe 13, respectively. Note that the flow of fluid when retracting the piston 1.2 is the opposite of the flow when extending it.

However, when extending the piston 1, it is only possible to extend it by a pre-designed length of the C pipe 13. Furthermore, if a multi-stage system is used, the number of pipes branching from pipe B will increase, making it even more complicated, so it is practically impossible to use a large number of stages.

In view of these points, the present invention allows the cylinder piping to be extended regardless of its length, and also simplifies the piping.
The main purpose of this invention is to propose this type of multi-stage actuator that can easily achieve multi-stage cylinders.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is a sectional view showing one embodiment of the present invention.

Reference numeral 15 denotes a cylinder tube, which is separated into a Ql chamber and a ■chamber by the first piston-cum-cylinder 30 and its small diameter portion 31. In addition, the first piston-cum-cylinder 30
The inside of the cylinder 35 also serves as a second piston and the small diameter portion 3.
6, it is separated into a chamber (1) and a chamber (2), and a piston 37 and a rod 38 are installed inside the second piston-cum-cylinder 35.
It is divided into the V chamber and the ■ chamber, forming a total of six chambers.

A fluid bypass passage 41 is formed in the small-diameter portion 36 of the second cylinder 35 which also serves as a piston between the chambers (1) and (2). A fluid bypass passage 42 is formed within the small diameter portion 31 of the cylinder 30 . (2) A conventional B pipe 52 is provided in the chamber.

It goes without saying that a sealing structure is provided between each chamber and the outside. Further, although the above is an example of a three-stage configuration, the configuration is not limited to this, and a large number of stages can be set. In this case, the piston 37 becomes the final stage.

Next, the operation of the present invention will be explained. First, when extending each cylinder, by flowing fluid into the I chamber from the A pipe 51 connected to the cylinder tube 15,
The fluid flowing into the first chamber is transferred to the first piston-cum-cylinder 3.
0 is extended to the right in the figure, a part of it passes through the hole 10 and flows into the chamber (2). (2) The fluid flowing into the chamber causes the second piston/cylinder 35 to expand rightward in the figure, while a portion of the fluid flows into the V chamber through the hole 11, causing the piston 37 to expand.

At this time, the fluid remaining in the chamber (2) passes through the bypass path 41 and flows into the chamber (2). In addition, the fluid that remained in the ■chamber is
Similarly, as the piston 37 is deflected, it flows into the chamber (1) through the bypass path 42. Since the air flows out from the chamber (1) to the outside through the B pipe 52 connected to the cylinder tube 15, no negative pressure is generated due to the expansion of the piston or the like.

In addition, each piston-cum-cylinder 30.35 and piston 3
The flow of fluid when contracting 7 is the opposite flow to the flow described above for expanding, so a detailed explanation will be omitted.

As described above, according to the present invention, the fluid chamber in the cylinder tube is separated into two by the first piston-cum-cylinder, and the fluid chamber is separated inside the first piston-cum-cylinder by the second piston-cum-cylinder. In a multi-stage actuator that is separated into two parts and has a fluid chamber separated into two by a piston in the final stage of the piston-cum-cylinder, a fluid communicating between the outside and the inside is contained in the small-diameter portion of each piston-cum-cylinder. Since a bypass path has been formed, when extending the cylinder, connect the above I, ■, and V from piping A.
By letting the fluid flow into the chamber, passing through the bypass path from the ■chamber, passing through the ■chamber, ■chamber, and flowing out from the B piping, only two external pipings are required, and the cylinders can be stacked in multiple stages. have an effect.

Therefore, according to the present invention, it is possible to obtain a large stroke in a small space. Therefore, the present invention can be used in various fields. For example, it is very suitable for use in devices for raising and lowering cars in parking lots.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional multi-stage actuator, and FIG. 2 is a sectional view showing an embodiment of the present invention.

Claims (1)

[Scope of Claims] The inside of the cylinder tube is separated into two fluid chambers by a first piston-cum-cylinder, and the inside of the first piston-cum-cylinder is also separated into two fluid chambers by a second piston-cum-cylinder. In a multi-stage actuator in which the interior of the final stage piston-cum-cylinder is also separated into two fluid chambers by a piston, a fluid bypass path communicating between the outside and the inside is provided in the small diameter portion of each piston-cum-cylinder. A multi-stage actuator characterized by the following: