KR102250853B1 - Hydraulic cylinder with built-in locking device - Google Patents

Abstract

The present invention relates to a hydraulic cylinder with a built-in locking apparatus, which comprises: a cylinder tube extended straight in a longitudinal direction, having a certain diameter; an end cap engaged with one end unit of the cylinder tube, having a locking unit providing support force; a reciprocating rod slidably inserted into the cylinder tube and extended toward an outer side on the other end unit of the cylinder tube; and a locking end placed on an end unit of the reciprocating rod to meet the locking unit and be fixed on the locking unit with the reciprocating rod completely inserted into the cylinder tube. As such, according to the present invention, the hydraulic cylinder with the built-in locking apparatus is able to have the piston rod completely inserted into the cylinder tube is supported by the built-in locking apparatus, to prevent the piston rod from abnormally escaping by a load applied from outside, and to have a great motion reliability. In addition, the locking apparatus supporting the piston rod is placed in the cylinder tube, so the outer structure is not complex and can be simply maintained.

Description

Hydraulic cylinder with built-in locking device

The present invention relates to a hydraulic cylinder applied to various industrial equipment, and more particularly, to a hydraulic cylinder with a built-in locking device, which prevents abnormal pulling out of a piston rod due to external force and thus has good operational reliability.

Hydraulic cylinders, which are widely used in various industrial fields, are important output equipment that converts the pressure energy of incompressible hydraulic oil into mechanical force.

The hydraulic cylinder includes a hollow cylinder tube extending in the longitudinal direction, a hydraulic pump for pressurizing hydraulic oil into the cylinder tube, and a piston rod inserted into the cylinder tube and linearly reciprocating under pressure of hydraulic oil. In addition, a valve for controlling the flow rate of hydraulic oil pressed into the cylinder tube and preventing reverse flow, and a control device for controlling the valve are installed outside the cylinder tube.

These hydraulic cylinders have features that can output a large force and can easily adjust the length of the piston rod, and are essentially used in almost all heavy equipment for civil engineering construction. For example, it is applied to excavators, blowers, cranes, dump trucks, and forklifts.

1 is a view showing a conventional hydraulic cylinder 19 connected to a boom 11 of an excavator.

As shown, the adapter 13 is linked to the end of the boom stand 11, and the bucket 15 and the tongs 17 are attached to the adapter 13 together. The adapter 13 rotates in the direction of the arrow a or the opposite direction by the main hydraulic cylinder 16 basically installed on the boom stand 11.

The bucket 15 is mounted on the adapter 13 and operates by the operation of the main hydraulic cylinder 16 to perform excavation. In addition, the tongs 17 are attachments fastened for the tongs operation, and are connected to the link bracket 11a of the boom through the hydraulic actuator 19.

The tongs 17 rotate by the operation of the hydraulic actuator 19 and serve to support and support the heavy object to be transported toward the bucket 15 side. For example, by rotating in the direction of arrow b, wood or waste materials of a size that cannot be stored in the bucket 15 are supported by the bucket 15.

These tongs 17 are lowered and used only when in use, and when not in use, they are rotated in the direction of the arrow c so as to be as close as possible to the side of the boom stand 11.

By the way, the tongs 17 are obviously an attachment for heavy equipment, and since their weight is heavy, they often rotate downward due to their own weight. That is, even though the operator did not lower the tongs 17, it goes down by itself.

The phenomenon that the tongs naturally descend occurs because the piston rod 19b is pulled out from the cylinder tube 19a downward. That is, the piston rod 19b, which has been completely upwardly inserted into the cylinder tube 19a, is lowered by receiving the load of the tongs 17. In order to solve this problem, a check valve for blocking the reverse flow of hydraulic oil may be installed on the outside of the cylinder tube 19a, but there is a limit to solving the above problem with only the check valve, but rather, another problem that heat is generated from the check valve. Occurs.

As a background technology related to a hydraulic cylinder, Korean Patent Publication No. 10-1151377 (hydraulic cylinder with a built-in check valve) has been disclosed. The disclosed hydraulic cylinder includes a cylindrical cylinder tube with an empty inside, a piston for maintaining hydraulic pressure by dividing a large chamber and a small chamber inside the cylinder tube, a cylinder rod for linearly reciprocating the piston in the cylinder tube, and a cylinder tube. A head cover and an end cover fixed to both ends to prevent leakage of hydraulic oil from the stroke end, a cushion ring and a cushion plunger respectively mounted on the outer surface and one end of the cylinder rod to absorb mechanical shock at the stroke end, Including a flow path formed in the head cover to communicate with the hydraulic oil port of the head cover, and a check valve installed to open and close the flow path, the flow path is closed at the stroke end to secure a cushioning function, and during initial movement after direction change at the stroke end In a hydraulic cylinder having a built-in check valve that secures a first thrust to pressurize the cushion ring and a second thrust to pressurize the piston by hydraulic oil supplied through a flow path that is opened during initial movement after direction change at the stroke end: , A seating portion extending at one end of the flow path to which a check valve is installed, a body coupled to the seating portion and forming a through hole communicating with the flow passage, a check ball opening and closing the through hole, and a pusher supporting the check ball under pressure And an elastic member for elastically biasing the through hole closed by a check ball by pressing the pusher in an initial state, and a plug screwed to the seating portion to support the elastic member.

Korean Patent Registration No. 10-1151377 (hydraulic cylinder with built-in check valve)

The present invention was created to solve the above problems, and an object of the present invention is to provide a hydraulic cylinder with a built-in locking device, since the piston rod completely inserted into the cylinder tube does not come out abnormally by the load applied from the outside. There is this.

A hydraulic cylinder incorporating a locking device of the present invention as a means of solving the problems for achieving the above object includes: a cylinder tube having a predetermined diameter and extending linearly in a longitudinal direction; An end cap coupled to one end of the cylinder tube and having a locking portion providing a support force; A reciprocating rod inserted into the cylinder tube so as to be slidably movable and extending outside the other end of the cylinder tube; And a locking end which is provided at an end of the reciprocating rod and is fixedly supported by the locking part by meeting the locking part in a state where the reciprocating rod is completely inserted into the cylinder tube.

In addition, a locking groove is formed in the locking end, and the locking part is provided with an elastic pressing means which acts to prevent the locking end from being separated from the locking by a force other than hydraulic pressure by elastically pressing the locking groove.

In addition, the locking end has a shape of a cylinder having a predetermined diameter, and the locking groove is a locking groove extending along the circumferential direction of the locking end.

In addition, the end cap includes a center hole for receiving and receiving the locking end, a chamber communicating with the center hole and providing a passage for passing hydraulic oil, and a connection port for opening the chamber to the outside and connecting a hydraulic hose. In addition, a plurality of the locking parts are disposed at an equal angle around the center hole.

In addition, around the center hole, a plurality of locking portion mounting holes opened to the center hole through the opening hole are formed symmetrically, and the locking portions are accommodated in each locking portion mounting hole and have a diameter larger than the diameter of the opening hole. It has a pressing ball, and a ball pressing portion for elastically pressing the pressing ball toward the engaging groove.

In addition, in the locking part mounting hole, it is opened to the center hole through the opening hole, and the inner diameter expands as the distance from the center hole increases, and the inclined passage for accommodating the pressure ball, and the inclined passage connected to the inclined passage, the radial direction of the end cap A female thread opening is formed.

In addition, the ball pressing unit includes a spring inserted into the inclined passage along with the pressing ball and elastically supporting the pressing ball, and a support cap screwed to the female screw hole and supporting the spring toward the pressing ball side.

In addition, the pressing ball maintains a state partially protruding toward the center hole through the opening hole by the action of the spring, and on the outer circumferential surface of the tip end of the locking end, when the locking end is inserted into the center groove, it is in contact with the pressing ball and pressurized. An entrance slope that spreads the ball in the radial direction is formed.

In addition, the end cap is provided with an insertion fixing part which is supported by an interview on the inner circumferential surface of the cylinder tube while being inserted and fixed to the inside of one end of the cylinder tube.

In the hydraulic cylinder with the locking device of the present invention as described above, since the piston rod completely inserted into the cylinder tube is supported by the built-in locking device, it does not come off abnormally by the load applied from the outside, so its operation reliability This is good.

In addition, since the locking device for supporting the piston rod is located inside the cylinder tube, the external structure is not complicated and maintenance is concise.

1 is a view for explaining a problem of a conventional hydraulic cylinder.
2 and 3 are partial cross-sectional views for explaining the internal structure and operation method of a hydraulic cylinder with a built-in locking device according to an embodiment of the present invention.
Figure 4 is a view showing a separate piston rod shown in Figure 2;
5 is a partial cross-sectional view of the end cap shown in FIG. 2.
FIG. 6 is a view showing the end cap of FIG. 5 viewed from a different angle.

Hereinafter, one embodiment according to the present invention will be described in more detail with reference to the accompanying drawings.

The hydraulic cylinder with a built-in locking device of the present invention has a configuration in which the piston rod completely inserted into the cylinder tube is not removed from the cylinder tube by force other than normal hydraulic pressure, and has a constant diameter and is a straight line in the longitudinal direction. An extended cylinder tube; An end cap coupled to one end of the cylinder tube and having a locking portion providing a support force; A reciprocating rod inserted into the cylinder tube so as to be slidably movable and extending outside the other end of the cylinder tube; It is provided at the end of the reciprocating rod and has a basic configuration of a locking end fixedly supported by the locking portion meeting the locking portion in a state in which the reciprocating rod is completely inserted into the cylinder tube.

2 and 3 are partial cross-sectional views for explaining the internal structure and operation method of the hydraulic cylinder 30 with a built-in locking device according to an embodiment of the present invention, and FIG. 4 is a separate piston rod shown in FIG. It is a drawing shown. In addition, FIG. 5 is a partial cross-sectional view of the end cap shown in FIG. 2, and FIG. 6 is a view showing the end cap of FIG. 5 viewed from a different angle.

FIG. 2 shows a state in which the piston rod 60 has been removed from the cylinder tube 40 to some extent, and FIG. 3 shows a state in which the piston rod 60 is completely inserted into the cylinder tube 40.

As shown, the hydraulic cylinder 30 with a built-in locking device according to the present embodiment, a cylinder tube 40, an end cap 45, a reciprocating rod 63, a locking end 65, a rod connecting portion 67 ).

The cylinder tube 40 provides an inner space 40a as a hollow pipe-shaped member having a predetermined diameter and extending linearly in the longitudinal direction. The inner space 40a is a space for accommodating the reciprocating rod 63 in a reciprocating manner. The size of the cylinder tube 40 may vary.

The end cap 45 is a member that is coupled to one end (right end in the drawing) of the cylinder tube 40 and incorporates a locking portion 45u. The locking part 45u accommodates and fixes a locking end 65, which will be described later, as shown in FIG. 3.

The locking part 45u together with the locking end 65 constitutes one locking device. In the locking device, in a state in which the reciprocating rod 63 is completely inserted into the cylinder tube 40 (the state of Fig. 3), the reciprocating rod 63 is moved to the cylinder tube 40 by a force other than hydraulic pressure. It is to prevent it from falling outside. Referring to FIG. 1 as a reference, it is to prevent the tongs 17 folded upward from being unfolded back to the bottom.

The end cap 45 is manufactured by cutting one metal block, and has an insertion fixing portion 45c inserted into the inside of one end of the cylinder tube 40. The insertion fixing part 45c is in close contact with the inner circumferential surface of the cylinder tube 40 while being inserted into the cylinder tube 40. The end cap 45 may be fixed to the cylinder tube 40 by a welding method in a state in which the insertion fixing part 45c is fitted to the cylinder tube 40.

Further, in the end cap 45, a center hole 45k, a chamber 45m, a connection port 45n, six locking part mounting ports 45g, and a pin hole 45b are formed.

The center hole 45k is a hole opened into the inner space 40a of the cylinder tube 40 and receives and accommodates the locking end 65 entering in the direction of the arrow m in FIG. 2. In addition, the chamber (45m) is a space provided behind the center hole, and is opened to the outside through the connection port (45n). The connection port 45n is a hole to which the hydraulic hose is connected.

The hydraulic oil pressurized through the hydraulic hose pushes the piston rod 60 to the outside of the cylinder tube 40 while being discharged to the center hole 45k via the chamber 45m. In addition, when the piston rod 60 moves in the direction of the arrow m due to the hydraulic oil being pressed into the opposite connection port 41, the hydraulic oil flowing in through the center hole 45k is passed and guided to the connection port 45n. The piston rod 60 is a combination of the reciprocating rod 63, the piston 61, and the locking end 65, which will be described later.

The pin hole 45b is a hole into which a link pin connecting the hydraulic cylinder 30 to the excavator is inserted.

The locking part mounting holes 45g are holes for accommodating the locking part 45u, and as shown in Fig. 6, six are arranged at an equal angle around the center hole 45k. In addition, the locking part mounting hole (45g) is located in the insertion fixing portion (45c).

Inside each locking part mounting port 45g, an inclined passage 45e and a female screw port 45d are provided. The inclined passage 45e is a hole opened to the center hole 45k through the opening hole 45f, and accommodates the pressing ball 45t.

The inner diameter of the inclined passage 45e expands as it moves away from the center hole 45k. In addition, the inner diameter of the opening hole (45f) is smaller than the diameter of the pressing ball (45t). Therefore, as shown in Figure 5, the pressing ball (45t) is accommodated in the inclined passage (45e) and is caught in the open hole (45f) and a part of it protrudes into the center hole (45k).

The female screw hole 45d is a hole connected to the inclined passage 45e and opened in the radial direction of the end cap, and a female screw thread is formed on the inner circumferential surface. The support cap (45q) is screwed to the female screw hole (45d).

A locking part 45u is installed inside each locking part mounting hole 45g. The locking portion 45u includes a pressing ball 45t and a ball pressing portion. The ball pressing unit serves to elastically fit the pressing ball (45t) into the locking groove (65b) and has a spring (45s) and a support cap (45q).

The pressing ball 45t is a spherical member made of steel, and, as shown in FIG. 3, presses the locking groove 65b in the direction of the arrow f. In addition, the spring (45s) is inserted into the inclined passage (45e) together with the pressure ball (45t) and elastically presses the pressure ball toward the engaging groove (65b).
At this time, the spring (45s) is preferably provided in a conical shape whose diameter gradually expands toward the support cap (45q) to correspond to the shape of the inclined passage (45e).

The support cap (45q) is a component that is screwed to the female threaded hole (45d) to support the spring (45s) to the pressure ball (45t) side. Of course, it is possible to adjust the force of the spring (45s) pressing the pressure ball (45t) by adjusting the degree of coupling of the support cap (45q) to the female screw hole (45d).

Meanwhile, the piston rod 60 is composed of a reciprocating rod 63, a locking end 65, a piston 61, and a rod connecting portion 67.

The reciprocating rod 63 is a round bar-shaped member having a constant diameter and extending straight in the longitudinal direction, accommodated in the cylinder tube 40, and reciprocates by the action of hydraulic pressure. It is a linear motion by hydraulic pressure pressed through the connection ports (41,45n).

The locking end 65 is provided at the right end of the drawing of the reciprocating rod 63, has a substantially cylindrical shape, and has an entrance inclined portion 65a and a locking groove 65b on the outer circumferential surface.

When the locking end 65 enters the center hole 45k, the entry slope 65a is an inclined surface that contacts the pressing ball 45t and spreads the pressing ball 45t in the radial direction. In addition, the engaging groove (65b) is a groove that accommodates and restrains the pressing ball (45t). The pressing ball (45t) elastically presses the locking groove (65b) by the action of the spring (45s) in a state inserted into the locking groove (65b). The pressing ball (45t) is to maintain a state that is fitted into the locking groove (65b) by the elastic force of the spring (45s). The spring 45s is compressed by the action of hydraulic pressure when hydraulic pressure is pressed through the connection port 45n, and causes the pressure ball 45t to retreat into the inclined passage 45e.

The entrance inclined portion 65a and the locking groove portion 65b take a shape extending in the circumferential direction of the locking end 65. In other words, it extends in the circumferential direction of the locking end 65 and has a shape where both ends meet after rotating one turn.

This locking end 65, in a state in which the reciprocating rod 63 is completely inserted into the cylinder tube 40, meets the locking portion 45u and is fixed to the locking portion, as shown in FIG. It does not come out from the end cap 45 by the force of.

Reference numeral 65d denotes a piston coupling part. The piston coupling portion 65d is a portion in which a male thread is formed on the outer circumferential surface, and is screwed with the coupling screw portion 61a of the piston 61. The piston 61 is in close contact with the inner circumferential surface of the cylinder tube 40 and prevents leakage of hydraulic oil. The rod connection 67 has a pin hole 67a and serves to connect the hydraulic cylinder 30 to the excavator.

In the end, the hydraulic cylinder 30 with the locking device according to the present embodiment configured as described above, the piston rod 60 in a state that is completely inserted into the cylinder tube 40, by a force other than the hydraulic pressure, the cylinder It has a structure that does not come off from the tube 40. In the case of replacing the hydraulic cylinder 19 shown in FIG. 1, the tongs 17 folded upwards do not fall to the bottom by their own weight.

In the above, the present invention has been described in detail through specific embodiments, but the present invention is not limited to the above embodiments, and various modifications are possible by those of ordinary skill within the scope of the technical idea of the present invention.

11: Boom stand 11a: Link bracket 13: Adapter
15: bucket 16: main hydraulic cylinder 17: tongs
19: additional hydraulic cylinder 19a: cylinder tube 19b: piston rod
30: hydraulic cylinder 40: cylinder tube 40a: internal space
41: connection port 45: end cap 45b: pin hole
45c: Insertion fixing portion 45d: Female threaded port 45e: Inclined passage
45f: Open hole 45g: Locking part mounting port 45k: Center hole
45m: Chamber 45n: Connection port 45q: Support cap
45s: spring 45t: pressurized ball 45u: locking part
60: piston rod 61: piston 61a: coupling screw portion
63: reciprocating rod 65: locking end 65a: entrance slope
65b: engaging groove 65d: piston coupling portion 67: rod connection portion
67a: pin hole

Claims (9)

A cylinder tube 40 having a predetermined diameter and extending straight in the longitudinal direction;
An end cap (45) coupled to one end of the cylinder tube (40) and having a locking part (45u) for providing a support force;
A reciprocating rod (63) inserted into the cylinder tube (40) so as to be slidably movable and extending outside the other end of the cylinder tube (40);
A locking end 65 that is provided at the end of the reciprocating rod 63 and is fixedly supported by the locking part 45u by meeting the locking part 45u while the reciprocating rod 63 is completely inserted into the cylinder tube 40. Includes,
The locking end 65 is formed with a locking groove (65b),
The locking part (45u) is provided with an elastic pressing means that acts to prevent the locking end (65) from being separated from the locking part (45u) by force other than hydraulic pressure by elastically pressing the locking groove part (65b),
The locking end 65 takes the shape of a cylinder having a predetermined diameter, and the locking groove 65b is a locking groove extending along the circumferential direction of the locking end 65,
The end cap 45 is a center hole 45k for receiving and receiving the locking end 65, a chamber 45m communicating with the center hole 45k and providing a passage for passing hydraulic oil, and the chamber ( 45m) is opened to the outside and has a connection port (45n) to which the hydraulic hose is connected, and a pin hole (45b) into which a link pin connecting the hydraulic cylinder (30) to the excavator is inserted,
A plurality of the locking portions 45u are equiangularly arranged around the center hole 45k,
A plurality of locking part mounting holes 45g opened to the center hole 45k through the opening hole 45f are formed symmetrically around the center hole 45k,
The locking part mounting hole (45g) is a hole for receiving the locking part (45u), six are arranged equiangular around the center hole (45k), and is located in the insertion fixing part (45c) to be described later,
The locking portion (45u) is accommodated in each locking portion (45g), the pressing ball (45t) having a diameter larger than the diameter of the opening hole (45f), and the pressing ball (45t) locking groove (65b) ) Has a ball pressing portion that elastically presses the side,
In the locking part mounting hole (45g), it is opened to the center hole (45k) through the opening hole (45f), the inner diameter is expanded as the distance from the center hole (45k) and accommodates the pressing ball (45t) An inclined passage 45e and a female screw hole 45d connected to the inclined passage 45e and opened in the radial direction of the end cap 45 are formed, and a female screw thread is formed on the inner circumferential surface of the female screw hole 45d,
The ball pressing unit is inserted into the inclined passageway (45e) together with the pressing ball (45t), a spring (45s) for elastically supporting the pressing ball (45t), and screwed to the female screw hole (45d), and a spring (45s) It is provided with a support cap (45q) to support the pressure ball (45t) side,
The pressing ball (45t), by the action of the spring (45s), maintains a state partially protruding toward the center hole (45k) through the opening hole (45f),
On the outer circumferential surface of the front end of the locking end 65, when the locking end 65 is inserted into the center hole 45k, an entry slope 65a that contacts the pressing ball 45t and spreads the pressing ball 45t in the radial direction is formed. And
The end cap 45 is provided with an insertion fixing part 45c that is supported for an interview on the inner circumferential surface of the cylinder tube 40 while being inserted and fixed inside the one end of the cylinder tube 40,
The reciprocating rod 63 and the locking end 65 constitute a piston rod 60,
The hydraulic oil pressurized through the hydraulic hose pushes the piston rod 60 to the outside of the cylinder tube 40 while being discharged to the center hole 45k via the chamber 45m,
The spring (45s) is a hydraulic cylinder with a locking device, characterized in that provided in the shape of a conical shape gradually expanding toward the support cap (45q) to correspond to the shape of the inclined passage (45e).







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