KR20090116186A - Hydraulic cylinder - Google Patents

Abstract

PURPOSE: A hydraulic cylinder is provided to prevent dust and rain from flowing into a piston rod and to lengthen service life of the piston rod. CONSTITUTION: A hydraulic cylinder comprises a cylinder(31), a piston(32), a piston rod(33), and a backward movement preventing part(34). The cylinder performs a role of a cylindrical case. The piston straightly reciprocates with the fluid pressure within the cylinder. The piston rod is joined to the piston and exposed out of the cylinder. A screw thread is formed in the exposed outer circumference of the piston rod. The backward movement preventing part extended to the cylinder when being screwed with the outer circumference of the piston rod.

Description

Hydraulic cylinder {Hydraulic cylinder}

The present invention relates to a hydraulic cylinder, and more particularly, the reverse direction in the piston rod extended state by being provided with an anti-retraction port extending toward the cylinder side in the state of being screwed to the outer peripheral surface of the outer end of the piston rod protruding out of the cylinder When the earth is retracted so that the lower end of the reverse guard is in close contact with the upper end of the cylinder, the piston rod extended by the support force of the reverse guard cannot be retracted into the cylinder and remains extended even when the hydraulic pressure is extinguished. It relates to a hydraulic cylinder.

Hydraulics are commonly used throughout the industry today, such as aircraft, automobiles, and machine tools. Hydraulics are forces obtained by compressing fluids such as mixtures of oil, water, and glycols. More versatile and similar in size, greater output is achieved, as well as quick and accurate response to control.

The device using the hydraulic pressure can be largely divided into a linear hydraulic device for a linear motion and a rotary hydraulic device for a rotary motion. Looking at a straight hydraulic device, that is, a hydraulic cylinder useful for a large force linear motion, As follows.

Hydraulic cylinders, as shown in Figures 1 and 2, the cylinder 11 which is a cylindrical case; A piston 12 reciprocating straight by hydraulic pressure in the cylinder 11; A piston rod 13 having an outer end projecting out of the cylinder 11 in a state where the inner end is coupled to the piston 12; It is a structure including a back, and is divided into a single-acting type and a double-acting type.

In the single-acting hydraulic cylinder, as illustrated in FIG. 1, an oil inlet hole H is provided at one end of the cylinder 11, and the hydraulic oil F introduced into the cylinder through the hydraulic oil injection hole H is provided. The piston 12 moves only to one side (upward in the drawing) due to the pressure of the piston, but the opposite movement of the piston is not made by hydraulic pressure, and is mainly used for lifting a heavy object, and the piston 12 Is lowered by the weight of the piston 12 and the piston rod 13 as the hydraulic oil F inside the cylinder 11 is discharged to the outside.

The double-acting hydraulic cylinder has been developed to solve the disadvantage of the single-acting hydraulic cylinder moving in one direction by the hydraulic pressure, as shown in Figure 2, the hydraulic oil injection hole (H) at both ends of the cylinder (11) Each of the piston 12 is configured to be upward or downward in accordance with the hydraulic oil injection hole H into which the hydraulic oil F is injected.

Such a hydraulic cylinder is used in almost all devices to which a force must be applied, but unlike a mechanical device capable of continuously maintaining the force applied during a long time in a stationary state, the hydraulic cylinder that is in operation during a stationary state There is a problem that it is difficult to maintain for a long time.

For example, when the screw is rotated to lift and stop the heavy load, the heavy load can be held in the lifted state for a long time.

However, in the case of stopping after lifting the heavy load by using the hydraulic cylinder, the hydraulic pressure that worked over time decreases and the heavy load gradually falls to a certain extent, which is due to the change in the volume of the hydraulic oil according to the temperature and the leakage of the hydraulic oil. And many other causes.

As described above, it is difficult for the hydraulic cylinder to maintain the same hydraulic pressure uniformly for a long time while the piston is stopped. When the hydraulic cylinder is used to maintain it for a long time after lifting or supporting a heavy load, Hydraulic losses can cause the piston to retract and allow heavy loads to move, resulting in large safety accidents.

Therefore, if you want to support heavy loads for a long time, you can use mechanical devices such as screws or mechanically or physically support the heavy loads with a separate pedestal while quickly supporting the primary loads in the hydraulic cylinder. The hydraulic cylinders must be removed and finally the pedestals to support the heavy loads for a long time.

That is, in the conventional hydraulic cylinder, even when the hydraulic pipe is locked so that the hydraulic oil is not discharged from the inside of the cylinder to the outside while the piston rod is extended to the outside of the cylinder to support any heavy load by injecting hydraulic oil into the cylinder. This flow creates a site where the hydraulic pressure on the piston rod is not constant and is reduced compared to the original hydraulic pressure.

Therefore, the conventional hydraulic cylinder has a problem that it is unsuitable for use for the purpose of supporting a heavy load that must be fixed for a long time while stopping the hydraulic supply means such as a hydraulic pump and the hydraulic pipe is locked.

The present invention has been made to solve the problem of the conventional hydraulic cylinder that could not support a heavy load for a long time because the hydraulic pressure exerted during the operation in the stopped state can not be maintained for a long time, An object of the present invention is to provide a hydraulic cylinder that can support a heavy load for a long time even in the state that the hydraulic pressure is extinguished.

The object of the present invention is achieved by a piston rod having a thread formed on the outer peripheral surface of the outer end exposed to the outside of the cylinder serving as a cylindrical case, and a backward prevention screw screwed to the outer peripheral surface of the outer end of the piston rod. .

In the hydraulic cylinder of the present invention, the piston rod cannot be retracted into the cylinder even when the hydraulic pressure is reduced or dissipated due to the reverse prevention mechanism screwed to the piston rod in the state of supporting the heavy load to the upper end of the cylinder. There is an advantage that can be stably supported for a long time.

And when the external load is supported for a long time in the outdoor using the hydraulic cylinder of the present invention, since the piston rod exposed to the outside of the cylinder is wrapped by the backward prevention port, rainwater or dust is prevented from entering the piston rod side as well as the outside It is protected from the direct impact of the bar, which has the advantage of extending the life of the piston rod.

In addition, since there is no hassle to separate the hydraulic cylinder after supporting the heavy load with other supporting means while supporting the heavy load as the hydraulic cylinder, the construction wall of construction or civil engineering There is an advantage that can improve labor productivity during installation work such as bridge.

The present invention relates to a hydraulic cylinder in which a proston rod extended out of a cylinder can be maintained for a long time as it is without retreating into the cylinder even when the hydraulic pressure applying means such as a hydraulic pump is stopped.

That is, the hydraulic cylinder of the present invention locks the hydraulic pipe so that the hydraulic oil is not discharged from the inside of the cylinder to the outside while the piston rod expands to support the heavy load by acting hydraulic pressure inside the cylinder, or completely discharges the hydraulic oil. It relates to a hydraulic cylinder, so that the length of the piston rod extended to the outside of the cylinder can be kept constant for a long time.

Hydraulic cylinder of the present invention as described above, the cylindrical cylinder serving as a case; A piston reciprocating straight in accordance with the pressure of the hydraulic oil in the cylinder; A piston rod extending outwardly through the cylinder while coupled to the piston; A backward prevention tool screwed to an outer end surface of the outer end of the piece cylinder rod and extending to the cylinder side; And the like.

The hydraulic cylinder of the present invention configured as described above has a technical and structural feature in a structure in which a backward preventing mechanism is screwed to the outer circumferential surface of the outer end of the piston rod, which will be described below.

In the hydraulic cylinder of the present invention, when the piston rod is extended, the backward prevention tool together with the piston rod moves in a direction away from the cylinder.

In other words, the reverse guard and the cylinder are separated from each other.

In the above state, by moving the reverse prevention screw screwed to the outer peripheral surface of the piston rod can be moved to the cylinder side to be in contact with the cylinder, the backward prevention screw screwed to the outer peripheral surface of the piston rod Is in contact with the cylinder, the piston rod cannot retract into the cylinder even if the hydraulic pressure on the piston rod is reduced or dissipated.

Details of the effects and the resulting effects, including the object and technical configuration of the present invention will be clearly understood by the following description with reference to the drawings showing a preferred embodiment of the present invention.

3 is a cross-sectional structural view of an embodiment hydraulic cylinder of the present invention.

As shown in the hydraulic cylinder of the present invention,

A cylinder 31 serving as a cylindrical case;

A piston (32) for reciprocating straight by hydraulic pressure in the cylinder (31);

A piston rod (33) which is exposed to the outside through a axial side of the cylinder (31) in a state coupled to the piston (32) and has a thread formed on its outer circumferential surface;

A reverse prevention tool 34 extending toward the cylinder 31 in a state of being screwed to the outer circumferential surface of the piston rod 33; And the like. Unexplained symbol "F" is "hydraulic oil".

In this case, the piston rod 33 should have a length such that the piston 32 is exposed to the outside of the cylinder 31 when the piston 32 is at the lowest point inside the cylinder 31, and the piston 32 has the cylinder 31. The thread should be formed on the outer circumferential surface of the piston rod 33 which is exposed to the outside when located at the lowest point in the interior.

That is, the thread forming portion of the piston rod 33 does not enter the cylinder 31.

In the hydraulic cylinder of the present invention constituted as described above, the reverse prevention tool 34,

A coupling member (34A) having a central portion screwed to an outer circumferential surface of the piston rod (33);

A side wall member 34B extending from the edge of the coupling member 34A toward the cylinder 31; It consists of.

At this time, it is preferable to couple a sealing member 34C, such as an O-ring, to the bottom surface of the side wall member 34B.

This prevents rain water, dust, and the like from entering the interior of the reverse stop 34, that is, the piston rod 33, when the reverse stop 34 is in contact with the cylinder 31, and at the same time, the piston rod 33. This is to prevent a direct external shock to the.

That is, when the external load is supported for a long time outdoors using the hydraulic cylinder of the present invention, the outer surface of the piston rod 33 can be more stably protected by the sealing member 34C.

Accordingly, the reverse prevention tool 34 has a groove or a gap, such as a tubular body, in which the side wall member 34B is opened so as to open only to the cylinder 31 side, that is, to take a cylindrical or enclosure structure with an inner space which is opened downward. It is desirable to make the body as long as it is constant.

However, if necessary, it may be composed of a plurality of side wall members 34B 'separated in the axial direction, as shown in FIG.

That is, the backward prevention device 34, even if the engaging member 34A screwed to the piston rod 33 rotates along the piston rod 33 toward the cylinder 31 side, the engaging member 34A and the cylinder ( The side wall member 34B is engaged as long as it can satisfy the structure that the side wall member 34B extends from the coupling member 34A to the cylinder 31 side so that the 31 can be spaced at regular intervals without contacting each other. The detailed structure or shape of the coupling member 34A and the side wall member 34B, such as one or more extending from the edge or bottom of the member 34A, is not limited to any particular form.

The hydraulic cylinder of the present invention configured as described above, as shown in Figure 5, by raising the reverse guard 34 together with the piston 32 by rotating the reverse guard 34 to the cylinder 31 side The backward prevention tool 34 and the cylinder 31 may be brought into contact with each other. Even when the hydraulic pressure acting on the piston 32 disappears, the backward prevention device 34 in which the piston rod 33 contacts the cylinder 31 is prevented. Supported by the do not retreat into the cylinder (31).

However, when the hydraulic cylinder of the present invention is a double-acting type, there is no problem, but when a single-acting type is used lying down in the horizontal direction, a problem occurs when retracting the expanded piston.

That is, when used in the vertical direction, the piston may descend by itself due to the weight of the piston and the piston rod, but when not used in the horizontal direction, as shown in Figure 6, the piston rod 33 is It is also preferable to interpose an elastic body 35 such as a coil spring or the like in the cylinder 31 located.

When the elastic body 35 is provided as described above, the compression force of the elastic body 35, which has been compressed together with the advancement of the piston 32, can act as a force for retracting the piston 32. Even when lying down in the horizontal direction, as long as the hydraulic pressure is dissipated, the piston can retract itself by the compressive elastic force of the elastic body 35.

Hydraulic cylinder of the present invention can be used fixed to a particular support bar, as shown in Figure 7, it may be provided with a fixing means on the bottom of the hydraulic cylinder, this fixing means,

A flow bracket (36) consisting of a cylinder coupling plate (36A) coupled to the bottom of the cylinder (31) and a rotating flange (36B) fixedly coupled to the bottom of the cylinder coupling plate (36A) and having a through hole (H1);

Fixed bracket 37 consisting of a fixed flange (37B) formed of an outer coupling plate (37A) coupled to the support, and a through hole (H2) fixedly coupled to the upper surface of the outer coupling plate (37A) and coincide with the through hole (H1). ); It can be configured as

At this time, the flow bracket 36 and the fixed bracket 37, after matching the through hole (H1) and the through hole (H2) and rotates the fastening member (P), such as a pin in the through hole (H1) and through hole (H2). Connected in such a way as to penetrate as possible.

1 is a cross-sectional structural view of a conventional single-acting hydraulic cylinder.

Figure 2 is a cross-sectional structural view of a conventional double-acting hydraulic cylinder.

Figure 3 is a cross-sectional structural view of the hydraulic cylinder of the first embodiment of the present invention.

Figure 4 is a perspective view of another embodiment of the reverse prevention constituting the hydraulic cylinder of the present invention.

Figure 5 shows the operating state of the hydraulic cylinder of the first embodiment of the present invention,

  (A) is a cross-sectional structural view showing the piston rod extended to the outside,

  (B) is a cross-sectional structural view showing the extended piston rod being fixed by the reverse guard.

Figure 6 is a partial cross-sectional structural view of a hydraulic cylinder of the second embodiment of the present invention.

7 is a partial perspective view of a hydraulic cylinder of the third embodiment of the present invention.

          ((Description of the reference sign for the main part of the drawing))

     31. Cylinder 32. Piston 33. Piston rod

     34. Anti-reverse 35. Elastic 36. Flow bracket

     36A. Cylinder coupling plate 36B. Rotating Flange 37.Mounting Bracket

     37A. Outer binding plate 37B. Fixed Flange F. Hydraulic Oil

     H1. Through hole H2. Through hole P. Fastening member

Claims (5)

A cylinder 31 serving as a cylindrical case; A piston (32) capable of reciprocating straight by hydraulic pressure in the cylinder (31); A piston rod (33) exposed to the outside of the cylinder (31) in a state coupled to the piston (32) and having a thread formed on the exposed outer peripheral surface thereof; Hydraulic cylinder, characterized in that configured; including; reverse protection port (34) extending to the cylinder (31) side in the state screwed to the outer peripheral surface of the piston rod (33). The method of claim 1, wherein the reverse guard 34, A coupling member (34A) screwed to an outer circumferential surface of the piston rod (33); A side wall member 34B extending from the coupling member 34A toward the cylinder 31; Hydraulic cylinder, characterized in that configured to include. The hydraulic cylinder according to claim 2, wherein the side wall member (34B) is a tubular body. 3. The hydraulic cylinder according to claim 2, wherein a sealing member (34C) which is in close contact with the outer surface of the cylinder (31) is coupled to the bottom surface of the side wall member (34B). The hydraulic cylinder according to claim 1, wherein an elastic body (35) is interposed in a cylinder (31) in which the piston rod (33) is located.

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