JP2528538Y2 - Hydraulic cylinder - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic cylinder used for a construction machine or the like.

[0002]

2. Description of the Related Art Conventionally, in a hydraulic cylinder of this type, when high pressure is applied by hydraulic pressure in a state where air built in at the time of assembling or air contained in hydraulic oil is gathered at an upper part in the cylinder, this is caused. The air may be compressed and the temperature may rise, causing the hydraulic oil to ignite or explode.In addition, the volume change due to the air compression makes the piston stroke unstable, so it is necessary to eliminate the air remaining in the cylinder. Means for opening the communication passage penetrating the piston at the movement end position of the piston to circulate the hydraulic oil, mixing remaining air into the circulated hydraulic oil, and discharging the mixed oil into the hydraulic oil tank Was provided.
That is, as shown in FIGS. 8 and 9, a communication hole is provided which penetrates a piston reciprocating in a cylinder in the direction of movement, and reverse openings communicating in one direction inward from openings at both ends of the communication hole. The valve body of the stop valve is integrally formed and provided so as to alternately open and close. In the movement end position of the piston, an operation piece which comes into contact with and operates on the inner end face of the cylinder to open the valve body of the check valve on the inner end face side is provided for both check valves in this example. ing. That is, in FIG. 8, a communication hole 5 is provided in the inner surface of the cylinder 1 by penetrating a reciprocally movable piston 3 in the direction of movement, and one end of the communication hole 5 extends inward from openings at both ends of the communication hole 5. Are provided, and one valve body 15 alternately contacting the respective valve seats 11 and 13 is provided so as to be reciprocally movable. Further, the valve body 1 is brought into contact with the inner end surface 19 of the cylinder 1 on the side of the cylinder head 17 via the ring members 21 and 23 to operate, and the valve element
5 is released from the valve seat 11 by a rod-shaped operating piece 25.
And are fixed together. Similarly, on the opposite side of the valve body 15,
Opposite side (bottom side) of cylinder 1 via floating piece 27
A rod-shaped operating piece 29 that abuts on the end face of the valve member 15 and opens the valve body 15 from the valve seat 13 on the opposite side is fixed. Valve seats 11, 13
The valve seat cylinders 30 and 32 provided with are connected at both ends by a hole 31 and a groove 33 communicating with each other, and are press-fitted and fixed in the communication hole 5. The floating piece 27 is slidably supported by a bearing 37 provided with a plurality of grooves 35, and the bearing 37 is press-fitted and fixed to the communication hole 5. The piston 3 includes a first ring 39, a divided intermediate ring 41, and a second ring 4.
3 and is fitted to the piston rod 45 and clamped and fixed to the step 47 by bolts (not shown). Friction rings 49, 49, a seal ring 51, and dust rings 53, 53 are engaged with the outer periphery of the piston 3.
In this configuration, when the hydraulic pressure sent from the hydraulic pump is applied to the bottom side (the right side of the piston 3 in the figure), the piston 3 is pushed leftward and moves. In this case, the valve element 15
Closes the valve seat 11 by hydraulic pressure, and the operating piece 25 protrudes from the end face of the piston 3 on the head side. When the piston 3 comes into contact with the inner end face 19 of the cylinder 1, the operating piece 25 is pushed, the valve body 15 opens the valve seat 11, and the pressure oil flows through the communication hole 5 and is returned to the hydraulic oil tank, and The air remaining in the tank is mixed with the working oil and discharged to the working oil tank.

Next, when the pressure oil is switched and the oil pressure is applied to the head side, the pressure oil momentarily flows through the communication hole 5 and presses the valve body 15 to close the valve seat 13. At the same time, the piston 3 moves to the right in the drawing due to the hydraulic pressure applied to the surface of the piston 3 on the head side.

[0004]

When the hydraulic pressure is switched to move the piston 3 in the opposite direction from the final end position, the valve body 15 moves and the check valve 13 closes.
During this time, the pressure oil does not rise and the pressure does not rise, but the check valve 13 closes and the pressure rises instantaneously, and this operation appears as a shock in the hydraulic pressure, and is applied to the machine operated by the cylinder 1. This caused a loud shock noise and shock vibration.

[0005]

The present invention is a double-acting hydraulic cylinder provided with communication holes 117 and 121 for supplying and discharging hydraulic oil at both ends, and reciprocates in a cylinder 55 together with a piston rod 65. A communication hole 67 penetrating in the movement direction is provided in the piston 63 to be moved, and an opening communicating with the valve seat cylinders 93 and 95 press-fitted at both ends of the communication hole 67 in one direction inward toward the respective insides. The valve bodies 77 and 79 of the stop valves 69 and 71 are separately provided, and the piston 6
The small-diameter operating piece 91 is brought into contact with the inner end face of the cylinder 55 at the movement end position of 3 to actuate to open the valve body 77 of the check valve 69 on the inner end face side.
7 and an elastic body 81 for urging the valve body 79 of the other check valve 71 in a direction to close the valve body 79. The outer peripheral surface of the valve body 77 is slidable in the communication hole 67. The operating piece 91 is slidably supported and provided on the valve seat cylinder 93 of the valve body 77. When the valve body 79 is seated on the valve seat 75, the valve body 77 is The amount of movement of the valve body 77 in the anti-seating direction is restricted by contacting the end on the opposite side of the valve seat, or the stepped portion 123 that projects into the communication hole 67 and locks one end of the bullet 81 is connected to the valve body 77. The valve body 77 is provided on the rear side on the side opposite to the valve seat so that the amount of movement of the valve body 77 in the direction opposite to the seat can be regulated.

[0006]

By opening the head side valve element 77, the air remaining in the cylinder can be easily discharged, and when the hydraulic pressure is switched in the opposite direction at the end position of the piston movement, the valve of the opposite check valve is opened. Since the body 79 is closed first by the ammunition, the piston starts to move at the same time as the switching, so that the hydraulic shock does not occur and the shock noise and shock vibration of the machine can be prevented. Further, by restricting the movement amount of the valve body 77, it is possible to prevent oil leakage from the valve section.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below in detail with reference to the drawings.

1 to 6, a cylinder head 57 is fixed to one end of a cylinder 55 by a bolt 59, a bottom body 61 is welded to the other end, and a reciprocally movable piston 63 is mounted inside the cylinder 55. It is fixed to a penetrating piston rod 65. Piston 63
Are provided in the movement direction, and check valves 69 and 71 communicating in one direction inward from the openings at both ends of the communication hole 67 are provided. Separate valve bodies 77 and 79 abutting on 73 and 75 are urged in a direction to close by a spring 81 interposed therebetween. A support ring 85 for holding a cushion ring 83 is provided on the inner end surface of the cylinder head 57.
Between the inner surface and a step portion 87 on the inner surface. Support ring 85
The rod-shaped operating piece 91 which contacts the inner end surface 89 of the cylinder 55 via the
7. Valve seat cylinder 9 provided with valve seats 73 and 75
3, 95 are a hole 97 and a groove 9 communicating with each other.
9, both ends communicate with each other, and are press-fitted and fixed in the communication holes 67.

Here, the operating piece 91 starts to abut on the inner end face 89, and operates to open the valve body 77 by a stroke until the piston 63 reaches the movement end position.

The movement of the valve body 77 for opening is restricted by abutting on the opposite end of the valve body 79 which is seated on the bottom side, as shown in FIG. At this time, the operating piece 91 projecting into the cylinder chamber is prevented from projecting.

The piston 63 is composed of a first ring 101, an intermediate ring 103 divided into two parts, and a second ring 105. The piston 63 is clamped and fixed between the steps 107 and 109 of the piston rod 65 via a cushion cylinder 111. Have been. A friction ring 113 and a seal ring 115 are engaged with the outer periphery of the piston 63. A communication hole 117 communicating with the inner diameter of the cushion ring 83 communicates with an oil hole 119 provided in the cylinder 55 in the cylinder head 57. An oil hole 121 communicating with the cylinder 55 penetrates the bottom 61.

In the above embodiment, when the hydraulic pressure sent from the hydraulic pump is applied to the oil hole 121, the piston 63
It moves by being pushed to the left in FIG. In this case, as shown in FIG. 2, the valve body 77 is closed by the spring 81 and the hydraulic pressure, and the operating piece 91 protrudes from the end face of the piston 63 on the cylinder head 57 side. When approaching the end of the movement, the cushion cylinder 111 moves to the cushion ring 83.
When the piston 63 moves, the area of the flow path on the low pressure side is gradually narrowed, and the movement of the piston 63 is buffered. At the end of movement, the operating piece 91 contacts the surface of the support ring 85 (the inner end surface 89 of the cylinder 55), the valve body 77 is released from the valve seat 73, and assumes the posture shown in FIG. Through the valves 71 and 69, the communication hole 117, the oil hole 11
After passing through 9, the air is returned to the hydraulic oil tank, and the air remaining in the cylinder 55 is mixed with the hydraulic oil and discharged into the hydraulic oil tank. Next, when the oil pressure is switched and oil pressure is applied to the oil hole 119, the valve element 77 is pushed by the operating piece 91 and the valve element 77 is open, but the other valve elements 79 are already closed by the spring 81. The piston 63 is brought into the posture shown in FIG.
The valve starts moving at the same time as the hydraulic pressure is switched, so that no hydraulic shock is caused by the closing operation of the valve body 79, and the outer periphery of the valve body 77 and the operating piece 91 integrated with the valve body 77 are slidably movable. Because of the support, the distance between the support parts is large, and it is stable against the load in the oblique direction of the valve body, and it does not generate scorching and galling, and it is safe especially against a large load at the moment when the operating piece comes into contact. .

Further, since the movement of the valve body 77 in the anti-seat direction is restricted by the contact with the seated bottom-side valve body 79, the head-side valve body 77 is indiscriminately caused by the flow of pressure oil or vibration. The valve does not move much, and oil leakage of the valve portion due to aching or galling can be prevented.

FIG. 7 shows a second embodiment.
The spring 81 is locked at one end by a step 123 projecting into the communication hole 67, and the valve body 77 is not subjected to the urging force of the spring. Since the step 123 is provided on the rear side of the valve body 77 opposite to the valve seat, the movement of the valve body 77 in the non-seating direction is restricted by the step 123.

In FIG. 7, the same reference numerals as those shown in FIGS. 1 to 6 represent the same components.

[0016]

[Effects of the Invention] Since the present invention has the structure as described in the claims, air remaining in the cylinder can be easily removed, and the hydraulic pressure when starting to move from the end position of the piston can be reduced. The shock can be eliminated and the generation of shock noise and shock vibration can be prevented. Also, since the two check valves are provided separately, when the reciprocating flow rates are different to equalize the reciprocating speeds of the pistons, the check valves in each direction are required as required. The size can be efficiently provided, and furthermore, it is possible to prevent burrs, galling, and wear due to operation of the valve body.

In addition, according to the present invention, since both the valve body and the valve seat are unitary, precision processing of each can be easily performed, leakage of hydraulic oil from the valve seat contact portion can be prevented, and reliable hydraulic operation can be performed. Can be done.

The tip of the operating piece is not limited to the one directly in contact with the inner surfaces of the cylinder head and the bottom, but may be in contact with the inner end surface of the cylinder in other parts such as the above-mentioned support ring. .

The present invention is not limited to the above-described embodiment, but can be implemented in other embodiments. The reference numerals in the claims do not limit the technical scope of the present invention.

[Brief description of the drawings]

FIG. 1 is a side sectional view of one embodiment of the present invention.

FIG. 2 is a side sectional view near a check valve.

FIG. 3 is a front view and a side sectional view of a main part, respectively.

FIG. 4 is a front view and a side sectional view of a main part, respectively.

FIG. 5 is a side sectional view showing the vicinity of a check valve in another posture.

FIG. 6 is a side sectional view of the vicinity of a check valve in another posture.

FIG. 7 is a side sectional view showing the vicinity of a check valve according to a second embodiment.

FIG. 8 is a side sectional view of the vicinity of a conventional check valve.

FIG. 9 is a front view of a main part of FIG. 8;

[Explanation of symbols]

 55 cylinder 63 piston 67 communication hole 69, 71 check valve 77, 79 valve element 81 bullet

Claims (1)

(57) [Scope of request for utility model registration] 1. Communication holes 117 and 12 for supplying and discharging hydraulic oil.
1 is a double-acting hydraulic cylinder provided at both ends, wherein a piston 63 reciprocating with a piston rod 65 in a cylinder 55 is provided with a communication hole 67 penetrating in the movement direction, and press-fitted into both ends of the communication hole 67. Fixed valve seat cylinder 9
The check valves 69, 71 communicating in one direction from the openings of the cylinders 3 and 95 in one direction are provided separately with valve bodies 77 and 79, respectively. A small-diameter operating piece 91 is provided integrally with the valve body 77 to abut on the inner end face and operate to open the valve body 77 of the check valve 69 on the inner end face side. A spring 81 is provided for urging the valve body 79 of the valve 71 in a direction to close the valve body. The outer peripheral surface of the valve body 77 is slidably supported in the communication hole 67, and the valve body 7 is slidably supported.
The operating piece 91 is slidably supported and provided in the valve seat cylinder 93 of No. 7, and when the valve body 79 is seated on the valve seat 75, the valve body 77 contacts the end of the valve body 79 on the side opposite to the valve seat. The amount of movement of the valve body 77 in the counter-seating direction is restricted, or the stepped portion 123 that projects into the communication hole 67 and locks one end of the bullet 81 is provided on the rear back of the valve body 77 on the side opposite to the valve seat. A hydraulic cylinder, wherein the amount of movement of the valve body 77 in the anti-seating direction can be regulated by the stepped portion 123.