JPH0673408U - Hydraulic cylinder - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a device capable of reliably deflating a construction hydraulic cylinder without generating a shock noise during reciprocating motion. [Structure] The present invention is provided with communication holes 117 and 1 for supplying and discharging hydraulic oil.
A double-acting hydraulic cylinder having 21 at both ends,
A communication hole 67 penetrating in the above-mentioned moving direction in the piston 63 that reciprocates in the cylinder 55 together with the piston rod 65.
And check valves 69, 71 of check valves 69, 71 which communicate in one direction from the openings of the valve seat cylinders 93, 95 press-fitted and fixed to both ends of the communication hole 67 inward. A small-diameter operating piece 91, which is provided separately, abuts against the inner end surface of the cylinder 55 at the end-of-motion position of the piston 63 and operates to open the valve body 77 of the check valve 69 on the inner end surface side. The elastic body 81 is integrally formed with the valve body 77 and is provided with a bullet 81 for urging the other check valve 71 in a direction to close the valve body 79. The outer peripheral surface of the valve body 77 is connected to the communication hole 67. In addition to being slidably supported, the operating piece 91 is slidably supported and provided on the valve seat cylinder 93 of the valve body 77.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a hydraulic cylinder used for construction machines and the like.

[0002]

[Prior art]

 Conventionally, in this type of hydraulic cylinder, if a high pressure is applied by the hydraulic pressure when the air built in at the time of assembly or the air contained in the hydraulic oil gathers in the upper part of the cylinder, There is a risk that the air will be compressed and the temperature will rise, causing the oil to ignite and explode, and the volume change due to air compression will make the piston stroke unstable, so it is necessary to eliminate the air remaining in the cylinder. Therefore, at the movement end position of the piston, the communication passage that penetrates the piston is opened to circulate the hydraulic oil, and the residual air is mixed with this circulating hydraulic oil and discharged into the hydraulic oil tank. Means were provided. That is, as shown in FIGS. 8 and 9, a communication hole is provided which penetrates the piston that reciprocates in the cylinder in the movement direction, and communicates inward from the openings at both ends of the communication hole inward. The valve body of the check valve was integrally formed and provided so as to alternately open and close. Further, at the end position of the movement of the piston, in this example, both check valves are provided with an operating piece that comes into contact with the inner end surface of the cylinder and operates to open the valve body of the check valve on the inner end surface side. ing. That is, in FIG. 8, communication holes 5 are provided in the inner surface of the cylinder 1 so as to penetrate the reciprocally movable piston 3 in the movement direction, and the communication holes 5 are inwardly directed from the openings at both ends. Check valves 7 and 9 that communicate with each other are provided, and one valve element 15 that alternately abuts each valve seat 11 and 13 is reciprocally movable. Further, a rod-shaped operating piece 25 for contacting and operating the inner end surface 19 of the cylinder 1 on the cylinder head 17 side via the ring bodies 21, 23 to open the valve body 15 from the valve seat 11 is integrally fixed to the valve body 15. is doing. Similarly, on the opposite side of the valve body 15, a rod-shaped operating piece for contacting the end face on the opposite side (bottom side) of the cylinder 1 via the floating piece 27 to open the valve body 15 from the valve seat 13 on the opposite side. 29 is stuck. The valve seat cylinders 30 and 32 provided with the valve seats 11 and 13 are connected at their both ends by a hole 31 and a groove 33 which communicate with each other, and are press-fitted and fixed in the communication hole 5. The floating piece 27 is slidably supported by a bearing body 37 having a plurality of groove portions 35, and the bearing body 37 is press-fitted and fixed to the communication hole 5. The piston 3 is composed of a first ring body 39, a divided intermediate ring body 41, and a second ring body 43. The piston 3 is fitted to a piston rod 45 and is clamped and fixed to a step portion 47 by a bolt (not shown). ing. Friction rings 49, 49, a seal ring 51, and dust rings 53, 53 are engaged with the outer circumference of the piston 3. In this configuration, when the hydraulic pressure sent from the hydraulic pump is applied to the bottom side (right side of the piston 3 in the figure), the piston 3 is pushed leftward and moves. In this case, the valve body 15 closes the valve seat 11 by hydraulic pressure, and the operating piece 25 projects from the end surface of the piston 3 on the head side. When the piston 3 comes into contact with the inner end surface 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. The air remaining inside is mixed with the hydraulic oil and discharged to the hydraulic oil tank.

Next, when the pressure oil is switched and a hydraulic 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 hydraulic pressure applied to the head side surface of the piston 3 causes the piston 3 to move to the right in the figure.

[0004]

[Problems to be solved by the device]

 When the hydraulic pressure is switched to move in the opposite direction from the final end position of the piston 3, the valve body 15 moves and the check valve 13 closes, but the hydraulic pressure flows during this period and the pressure does not rise. The check valve 13 is closed to increase the pressure at an instant, and this operation is expressed as a shock in the hydraulic pressure, which causes a large shock noise and shock vibration in the machine operated by the cylinder 1. Was there.

[0005]

[Means for Solving the Problems]

 The present invention is a double-acting hydraulic cylinder provided with communicating holes 117 and 121 for supplying and discharging hydraulic oil at both ends thereof, in which the piston 63, which reciprocates in the cylinder 55 together with the piston rod 65, moves in the direction of movement. Valves of the check valves 69, 71 are provided with communicating holes 67 penetrating therethrough and communicate in one direction from the openings of the valve seat cylinders 93, 95 press-fitted at both ends of the communicating holes 67 inward. The bodies 77 and 79 are provided as separate bodies, and abut on the inner end surface of the cylinder 55 at the movement end position of the piston 63 and operate to open the valve body 77 of the check valve 69 on the inner end surface side. An operating piece 91 having a small diameter is integrally formed with the valve body 77, and an ammunition 81 for urging the valve body 79 of the other check valve 71 in a closing direction is provided. Slide the surface into the communication hole 67. While rotatably supported, the operation Dohen 91 on the valve seat sleeve 93 of the valve body 77 is obtained provided supported slidably.

[0006]

[Action]

 This allows the air remaining in the cylinder to be easily discharged, and when the hydraulic pressure is switched in the opposite direction at the end position of the piston movement, the check valve on the opposite side is closed earlier by the ammunition. , The piston does not start moving at the same time as switching, and the shock noise and shock vibration of the machine can be prevented without causing hydraulic shock.

[0007]

【Example】

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

1 to 6, a cylinder head 57 is fixed to a cylinder 55 at one end by a bolt 59, a bottom body 61 is welded to the other end, and a reciprocally movable piston 63 is provided inside the cylinder head 57. It is fixed to a piston rod 65 that penetrates through. A communicating hole 67 is provided penetrating the piston 63 in the movement direction, and check valves 69 and 71 are provided to communicate in one direction from the openings at both ends of the communicating hole 67 toward the inside. Separate valve bodies 77, 79 that abut the respective valve seats 73, 75 are urged in a closing direction by a bullet 81 interposed therebetween. A support ring 85 holding the cushion ring 83 is sandwiched between the cylinder head 57 and the step portion 87 on the inner surface of the cylinder 55. A rod-shaped operating piece 91 that abuts the inner end surface 89 of the cylinder 55 via the support ring 85 and opens the valve body 77 from the valve seat 73 is fixed to the valve body 77. The valve seat cylinders 93 and 95 provided with the valve seats 73 and 75 are connected at their both ends by a hole 97 and a groove 99 which communicate with each other, and are press-fitted and fixed in the communication hole 67. The piston 63 includes a first ring body 101, a divided intermediate ring body 103, a second ring body 103, and a second ring body 105, and a cushion cylinder 111 is interposed between the step portions 107 and 109 of the piston rod 65. It is held and fixed. A friction ring 113 and a seal ring 115 are engaged with the outer circumference of the piston 63. The cylinder head 57 has a communication hole 117 communicating with the inner diameter of the cushion ring 83 and an oil hole 119 provided in the cylinder 55. An oil hole 121 communicating with the inside of the cylinder 55 penetrates through 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 is pushed and moves leftward in FIG. In this case, as shown in FIG. 2, the valve body 77 is closed by the bullet 81 and the hydraulic pressure, and the operating piece 91 projects from the end surface of the piston 63 on the cylinder head 57 side. When the end of the movement is approached, the cushion cylinder 111 begins to enter the cushion ring 83, and the flow passage area on the low pressure side is gradually narrowed as the cushion cylinder 111 moves, and the movement of the piston 63 is damped. At the end of the 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 the posture shown in FIG. 5 is obtained. After passing through the valves 71 and 69, through the communication hole 117 and the oil hole 119, the air is returned to the working oil tank, and the air remaining in the cylinder 55 is mixed with the working oil and discharged into the working oil tank. Next, when the oil pressure is switched to the oil hole 119 and the oil pressure is applied to the oil hole 119, the valve element 77 is opened by being pushed by the operating piece 91, but the other valve elements 79 are already closed by the ammunition 81. The posture shown in FIG. 6 causes the piston 63 to start moving at the same time as the hydraulic pressure is switched. Therefore, the hydraulic shock due to the closing operation of the valve body 79 does not occur, and the outer circumference of the valve body 77 and the valve Since the body 77 and the one operating piece 91 are slidably supported, the distance between the supporting portions is large, and the valve body is stable against the load in the tilting direction of the valve body, and there is no shedding or galling. It is safe against a large load at the moment of contact of the operating piece.

FIG. 7 shows the second embodiment. One end of the bullet 81 is locked by the step portion 123 protruding into the communication hole 67, and the valve body 77 is urged by the bullet. I have not received it.

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

[0012]

[Effect of device]

 Since the present invention has the structure as set forth in the claims, it is possible to easily remove the air remaining in the cylinder, and to eliminate the hydraulic shock when starting to move from the end position of the piston. It is possible to prevent the generation of shock noise and shock vibration. In addition, since the two check valves are provided separately, when the pistons are provided with different reciprocating flow rates in order to equalize the reciprocating speeds of the pistons, check valves in each direction are required. It is possible to efficiently install the valve body in a suitable size and prevent the valve element actuating valve or the like from sticking, galling, and wear.

In addition, according to the present invention, since the valve body and the valve seat are a single body, it is possible to easily perform precision machining of each, prevent leakage of hydraulic oil from the valve seat abutting portion, and perform reliable hydraulic operation. Is possible.

The tip of the actuating piece is not limited to one that directly contacts the inner surfaces of the cylinder head and the bottom, and it may contact the inner end surface of the cylinder of another component such as the support ring described above. Good.

It should be noted that the present invention is not limited to the above-described embodiment, but can be implemented in other modes. Further, the reference signs in the claims do not limit the technical scope of the present invention.

[Brief description of drawings]

FIG. 1 is a side sectional view of an 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 of the vicinity of the check valve in different postures.

FIG. 6 is a side sectional view of the vicinity of the check valve in different postures.

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

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

9 is a front view of the main part of FIG.

[Explanation of symbols]

 55 cylinder 63 piston 67 communication hole 69,71 check valve 77,79 valve body 81 ammunition

Claims (1)

[Scope of utility model registration request] 1. Communication holes 117 and 12 for supplying and discharging hydraulic oil.
1 is a double-acting hydraulic cylinder provided at both ends, in which a piston 63 that reciprocates in a cylinder 55 together with a piston rod 65 is provided with a communication hole 67 penetrating in the movement direction, and press-fitted at both ends of the communication hole 67. Fixed valve seat cylinder 9
The valve bodies 77 and 79 of the check valves 69 and 71, which communicate in one direction from the openings of the cylinders 3, 95 inward, are provided separately, and at the movement end position of the piston 63, the cylinder 55 of the cylinder 55 moves. A small-diameter operating piece 91 is provided integrally with the valve body 77 for abutting and operating the inner end surface to open the valve body 77 of the check valve 69 on the inner end surface side. An ammunition 81 for urging the valve body 79 of the valve 71 in a closing direction is provided to slidably support the outer peripheral surface of the valve body 77 in the communication hole 67, and
7. A hydraulic cylinder characterized in that the operating piece 91 is slidably supported on the valve seat cylinder 93 of No. 7 and provided.