JPH0720404Y2 - Hydraulic cylinder device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention relates to a hydraulic cylinder device used in a construction machine or the like.

(Prior Art and Problems to be Solved) Conventionally, in this type of hydraulic cylinder device, a cushion cylinder which is in contact with the end face of the piston and is fitted and fixed to the outer circumference of the piston rod is provided, and the piston cylinder is provided on the inner face of the cylinder head. Along with the reciprocating movement of the cushion cylinder, a cushion hole through which the cushion cylinder comes in and out is opened, the cushion hole is communicated with the oil hole, and the outer periphery of the cushion cylinder is inclined. Generally, due to the structure, the eccentric dimension between the cushion cylinder and the cushion hole is larger than the gap between the cushion cylinder and cushion hole, which is necessary for cushioning. However, the cushion ring and its mounting structure are complicated and cannot be manufactured at low cost.

(Means and Actions for Solving the Problems) The present invention is one in which a cushion cylinder is loosely fitted to the outer periphery of a piston rod, and a heap portion made of a wear resistant material is provided on the inner diameter portion of the cushion hole opening. The structure is simple and inexpensive to manufacture, and the cushion cylinder can move in the radial direction to adjust the eccentricity.When the cushion pressure is applied, the hydraulic pressure is applied to the inside diameter of the cushion cylinder and the outside diameter expands. The smaller the gap between the cushion hole and the cushion hole, the higher the cushion pressure and the better the cushioning performance.

Also, since the sliding resistance is reduced by providing the helix, the cushion pressure resists the sliding resistance and presses the piston side end face of the cushion cylinder, and the opposite face is brought into close contact with the step part of the piston rod. It is possible to prevent pressure oil leakage.

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

In the figure, a cylinder head 3 is fixed to one end of a cylinder 1 by a bolt 5 and a bottom body 7 is welded to the other end of the cylinder 1. Is stuck to. A communication hole 13 is provided penetrating the piston 9 in the direction of movement, and check valves 15 and 17 are provided which communicate in one direction from the openings at both ends of the communication hole 13 toward the inside thereof. Separate valve bodies 23, 25 that come into contact with the valve seats 19, 21 are urged in a direction to be closed by a bullet 27 interposed therebetween.
The valve body 25 is seated on the valve seat 19 by abutting on the inner end surface of the cylinder head 3.
A rod-shaped actuating piece 29 that is released from is fixed to the valve body 23.
The valve seat cylinders 31 and 33 having the valve seats 19 and 21 are connected at their both ends by a hole 35 and a groove 37 which communicate with each other, and are press-fitted and fixed in the communication hole 13. The valve body 25 is provided with a throttle hole 39 that connects the hole portion 35 and the inside of the valve body 25. The piston 9 is composed of a first ring body 43 fixed to each other by a bolt 41, an intermediate ring body 45 divided into two, and a second ring body 47, and a step portion 49 of the piston rod 11;
It is sandwiched and fixed between 51 through a cushion cylinder 53. A passage 54 communicating with the communication hole 13 is provided through the intermediate ring body 45 and the second ring body 47. The cushion cylinder 53 is loosely engaged with the piston rod 11 with a proper gap, and a groove 55 is formed on the outer periphery in the axial direction to increase the cross-sectional area toward the outside. The cylinder head 3 is provided with a cushion hole 57 into which the cushion cylinder 53 is fitted, and an oil hole is provided through the communication hole 59.
It communicates with 61. Friction ring 6 on the outer circumference of piston 9
3, the seal ring 65 and the dust ring 67 are engaged. A metal deposit 69 made of a wear-resistant material is formed near the opening of the inner diameter of the cushion hole 57.

The root portion 75 of the conical buffer rod 73 engages with the engagement hole 71 that is open to the end surface of the piston rod 11, and the groove 77 provided on the outer periphery of the root portion 75 and the groove 77 on the inner surface of the engagement hole 71. Is locked by a plurality of steel balls 81 fitted in a groove 79 provided so as to face each other. An insertion hole 83 for communicating the groove 79 and the outer circumference to insert and withdraw the steel ball 81 is closed by a screw 86. Bottom body 7
A buffer hole 85 through which the buffer rod 73 comes in and out is opened at this point and communicates with the oil passage 87. The opening 89 of the buffer hole 85 is formed in a conical shape, and when the end surface of the piston rod 11 abuts, the opening 89 communicates with the inside of the cylinder 1 by a circular recess 91 provided on the inner surface of the bottom body 7. A throttling hole 93 is formed in the center of the buffer rod 73.
Penetrates and communicates the buffer hole 85 with the inside of the cylinder 1. The throttle hole 93 communicates with the conical surface on the outer periphery by a plurality of communication holes 95. Inclined surfaces 97 and 99 are formed at the outer peripheral edge of the buffer rod 73 and the peripheral edge of the throttle hole 93, respectively.

In the above structure, when pressure oil is sent from the oil passage 87, the pressure oil presses the piston 9 through the throttle hole 93 and gradually moves it to the left in FIG. The oil amount increases as the conical outer periphery of the buffer rod 73 comes out of the buffer hole 85, and the speed of the piston 9 gradually increases. When the piston 9 comes close to the cylinder head 3, the cushion cylinder 53 has a cushion hole.
Since the cross-sectional area of the groove 55 on the outer circumference of the cushion cylinder 53 becomes smaller as it starts to penetrate into the cylinder 57, the cylinder 1 on the rear surface of the piston 9 (on the left side in FIG. 1) is cut into the cushion hole.
The amount of oil discharged to the oil hole 61 via 57 is reduced and the piston 9
The speed of is buffered. Piston 9 is cylinder head 3
Immediately before coming into contact with the cylinder head 3, the operating piece 29 comes into contact with the cylinder head 3 to open the check valve 15.
4, discharged from the oil hole 61 through the communication hole 13.

On the contrary, when the operation valve (not shown) is switched and the pressure oil is released from the oil port 87, the piston 9 moves to the first position due to the gravity load.
Moving to the right in the figure, the oil in the chamber on the bottom body 7 side of the piston 9 is discharged from the oil hole 87 via the buffer hole 85. When the buffer rod 73 begins to enter the buffer hole 85, the flow path is gradually narrowed and the speed of the piston 9 is reduced to buffer the flow. When the buffer rod 73 begins to enter the buffer hole 85, the hydraulic pressure in the chamber between the piston 9 and the bottom body 7 rapidly increases, and the hydraulic pressure in the communication hole 13 also increases through the check valve 17, but the piston 9 stops. Then, the pressure oil is not discharged and trapped through the throttle hole 39. Further, since the outer peripheral surface of the cushion cylinder 53 is inclined, only the opening edge portion of the inner diameter surface of the cushion hole 57 contacts the cushion cylinder 53, but this portion forms the metal deposit 69 with the wear resistant material. Therefore, the amount of wear is small, and therefore, even if the edge of the opening having a large circumferential dimension is slightly worn, the flow rate is not largely changed.

[Effect of device]

According to the present invention, since only the opening edge of the cushion hole needs to be plated with a wear-resistant material, the structure is simple and the cost is low, and the eccentricity between the cushion cylinder and the cushion hole can be adjusted. In addition, the cushioning pressure is small and the cushioning effect is large.

[Brief description of drawings]

FIG. 1 is a side sectional view of an embodiment of the present invention, FIG. 2 is an enlarged side sectional view of an essential part, and FIGS. 3 and 4 are an enlarged front view, an enlarged side sectional view of the essential part, and FIG. The figure is a plan view of another main part. 1 ... Cylinder 3 ... Cylinder head 9 ... Piston 11 ... Piston rod 53 ... Cushion cylinder 57 ... Cushion hole 61 ... Oil passage 69 ... Metal deposit

Claims (1)

[Scope of utility model registration request] 1. A piston 9 which is reciprocally fitted in a cylinder 1 and a piston rod 11 which secures the piston 9 at one end are provided, and contact the end face of the piston 9,
A cushion cylinder 53 that fits around the outer periphery of the piston rod 11.
And a cushion hole 57 through which the cushion cylinder 53 moves in and out according to the reciprocating motion of the piston 9, is provided in the inner surface of the cylinder head 3, and the cushion hole 57 is provided in communication with the oil passage 61. A hydraulic cylinder device characterized in that a raised portion 69 made of a wear-resistant material is provided on the inner diameter of the opening.