JP2554286Y2 - Hydraulic cylinder cushion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a cushion device that prevents a piston from slamming into the end of a cylinder when a hydraulic cylinder is used.

(Prior Art) As an apparatus of this kind, for example, an O-ring seals between a piston rod end protruding outward from a piston and a cushion hole communicating with a port at a cylinder end, and a port and a cylinder are connected. There are devices connected with a communication hole provided with a flow control valve and a communication hole provided with a check valve which opens only from a port toward the cylinder.

However, such devices have become increasingly obsolete over time.
The ring may be worn, or the check valve may malfunction due to minute solids mixed in the oil.

An apparatus as shown in FIGS. 5 to 7 which solves this problem is disclosed in Japanese Utility Model Publication No. 48-33504.

In the figure, 1 is a cylinder, 2 is an end plate of the cylinder 1, 3 is a piston, 4 is a piston rod, 5 is a port provided in the end plate 2, and 6 is a cushion having a diameter through which the end of the piston rod 4 can play. A hole connects the port 5 and the cylinder 1.

A plate-like seal ring 8 that can be slidably fitted to the end (left end in FIG. 5) of the piston rod 4 is fitted into the annular groove 7 cut out in the cushion hole 6.

The seal ring 8 is made of metal or synthetic resin, and has a groove 9 formed on the inner side surface (the right side in the figure) in the radial direction as shown in FIGS.

The port 5 formed in the end plate 2 communicates with the cylinder 1 via the adjustment valve 10 and the communication hole 11.

As shown in FIG. 6, the above-mentioned device uses the high-pressure oil on the right side of the piston 3 to move the piston 3 together with the piston 3
Moves to the left and the end enters the cushion hole, the tip of the piston rod 4 fits into the seal ring 8. After the distal end of the piston rod 4 is fitted to the seal ring 8 as described above, both move integrally, so that the sixth
As shown in the figure, the seal ring 8 is pressed against the left surface of the annular groove 7. Therefore, the hydraulic oil on the left side of the piston 3 is prevented from flowing out to the port 5 through the cushion hole 6.

Then, the hydraulic oil on the left side of the piston is regulated by the regulating valve 10 and flows out of the port 5 little by little. Therefore, the piston 3 is decelerated by the flow resistance at this time, and the impact force is reduced.

When high-pressure oil is supplied from the port 5 from the above state, the seal ring 8 slides rightward and presses against the right surface of the annular groove 7 as shown in FIG. Therefore, the seal ring 8
The high-pressure oil flows through a gap between the annular groove 7 and the left side surface and the outer peripheral surface of the high pressure oil. If high-pressure oil flows in this way, the piston 3
Quickly to the right, and the piston rod 4
Leave more.

(Problem to be solved by the present invention) The conventional device as described above, when assembling,
It is necessary to forcibly elastically reduce the diameter of the seal ring 8 and incorporate it into the annular groove 7. Therefore, when the seal ring 8 is made of metal, its thickness must be extremely thin. However, when the thickness of the seal ring 8 is reduced, the cushion ring is worn under a high load, and the performance thereof is deteriorated.

When the cushion ring is made of a synthetic resin, it can be made thicker to some extent. However, since the synthetic resin is inferior in abrasion resistance, there is a problem that the problem of performance degradation cannot be solved.

An object of the present invention is to provide a hydraulic cylinder cushion device that can be easily fitted even if the thickness of the cushion ring is large.

(Means for Solving the Problems) In the present invention, a sliding hole coaxial with the cushion hole and having a large diameter is continuously provided at the entrance of the cushion hole protruding from the center of the inner surface of the end plate of the cylinder. The boundary between the sliding hole and the cushion hole is a stepped portion. The sliding hole has a smaller outer diameter than the sliding hole, and a hole in which the end of the piston rod can be slidably fitted in the center. A plate-shaped seal ring formed with a hole, and a stop ring formed with an axial communication groove in the inner surface of the hole in the same manner as above are fitted in order, and the stop ring is attached to an inner surface end of the sliding hole. A snap ring for preventing the slide ring from coming off is fitted, while a flow path constituted by the slide hole and the seal ring, and a contact surface between the seal ring and the stop ring, Cushion with a radial groove formed in the cushion It is characterized in that the seal ring is sometimes brought into contact with the inner surface of the step, the seal ring is sandwiched between the step and the stop ring, and a gap is formed between the step and the seal ring when returning.

(Operation of the present invention) In the device of the present invention, the seal ring and the stop ring are slidably fitted, and the seal ring prevents the seal ring from coming off. Is not limited, and the durability can be improved.

(Embodiment of the present invention) Figs. 1 to 4 show an embodiment of the present invention, and the same members as those of the above-mentioned conventional device are denoted by the same reference numerals, and description thereof will be omitted.

At the outer end of the cushion hole 6 of this embodiment, a sliding hole 51 coaxial with the cushion hole 6 and having a diameter larger than that of the cushion hole 6 is continuously formed and a step 15 is formed. The seal ring 8 similar to the conventional device and the stop ring 52 are slidably fitted in the sliding hole 51.

A number of communication grooves 53 are cut out in the stop ring 52. The stop ring 52 thus configured is connected to the sliding hole 51 by a snap ring 54 fitted to the inner end of the sliding hole 51.
I try not to fall out.

Further, a cushion groove 61 which passes through the center of the stop ring 52 from the end surface is formed in the peripheral surface of the end portion of the piston rod 4, and the depth of the groove 61 is increased from the above-mentioned end to the inner end. Therefore, it shall be gradually shallower.

In this device, as shown in FIG. 2, when the piston 3 advances leftward and approaches the end plate 2, the piston rod 4 is fitted to the stop ring 52 and the seal ring 8. When the piston rod 4 fits into the two rings 52, 8 as described above, both the rings move accordingly, and the seal ring 8 is pressed against the inner bottom surface of the sliding hole 51 as shown in FIG.

When the seal ring 8 is pressed against the inner bottom surface of the slide hole 51, the left side of the piston 3 and the port 5 communicate only through the cushion groove 61. Therefore, the working oil on the left side of the piston 3 flows out little by little from the cushion groove 61 to the port 5, and the flow resistance at this time gives the piston 3 a cushioning action.

When high-pressure oil is supplied from the port 5, the high-pressure oil flows through the cushion groove 61 and moves the piston 3 to the right. Then, at this time, as shown in FIG.
The vehicle advances rightward in the sliding hole 51 until the 52 comes into contact with the snap ring 54.

Then, the high-pressure oil in the port 5 passes through the gap between the left side surface and the outer peripheral surface of the seal ring 8 and the sliding hole 51, the radiation groove of the seal ring 8, and flows into the cylinder 1 through the communication groove 53 of the stop ring 52. Then, the piston 3 is quickly moved rightward, and the piston rod 4 is separated from the seal ring 8 and the stop ring 52.

(Effect of the present invention) In the device of the present invention, the seal ring and the stop ring are fitted from the end faces opened in the sliding holes, and the snap ring is used to prevent the stop ring from coming off. Therefore, it is not necessary to incorporate the metal seal ring into a metal seal ring having a desired thickness. Therefore, the durability is remarkably increased and the assembling work is facilitated.

Further, the plate-shaped seal ring of the present invention comes into contact with the inner surface of the step portion when the piston is cushioned, and exhibits a sealing effect. At this time, the seal ring is sandwiched between the inner surface of the stepped portion and the stop ring, so that the seal ring is not easily deformed.

Such a seal ring moves when a fluid pressure from the port 5 acts upon the return operation of the piston. A gap is created between the seal ring and the sliding hole by the movement of the seal ring. This gap reliably communicates with the piston through the flow path provided between the seal ring and the sliding hole, the groove formed in the seal ring, and the communication groove formed in the stop ring.
With such communication, the fluid from the port 5 is supplied to the piston through these passages, so that the responsiveness at the time of the return operation is improved. Since the communication groove is not closed by the seal ring, the flow rate flowing through these passages is constant. Therefore, the piston strokes at a constant speed.

[Brief description of the drawings]

FIG. 1 is a partially longitudinal side view of a hydraulic cylinder to which an embodiment of the present invention is applied, FIG. 2 is an enlarged view of a main part of FIG. 1 when a cushion is applied, and FIG. 3 is an enlarged view of a first main part when a piston is pressed. FIG. 4 is a cross-sectional view taken along the line IV-IV of FIG. 2, FIG. 5 is a partially longitudinal side view of a hydraulic cylinder to which the conventional device is applied, FIG. 6 is an enlarged view of a main part of FIG. Fig. 7 shows the first state when the piston is pressed.
It is a figure principal part enlarged view. 1 ... cylinder, 2 ... end plate, 4 ... piston rod,
5 ... port, 6 ... cushion hole, 8 ... seal ring, 9 ... radiation groove which is the groove of the present invention, 10 ... adjustment valve,
11 ... communicating hole, 15 ... step, 51 ... sliding hole, 52 ... stop ring, 53 ... communicating groove, 54 ... snap ring, 61
…… Cushion grooves.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Sho-56-141202 (JP, U) Japanese Utility Model Sho-61-94602 (JP, U) Japanese Utility Model Sho-58-82509 (JP, U) Japanese Utility Model Sho-50 104093 (JP, U) Jiko 60-21522 (JP, Y2) Jiko 51-47179 (JP, Y2)

Claims (1)

(57) [Scope of request for utility model registration] A large-diameter sliding hole coaxial with the cushion hole is continuously provided at the entrance of the cushion hole protruding from the center of the inner surface of the end plate of the cylinder. A plate-shaped seal ring in which the boundary is a stepped portion, the outer diameter of the sliding hole is smaller than that of the sliding hole, and a hole is formed at the center where the end of the piston rod can be slidably fitted. And a stop ring in which a hole is formed in the same manner and an axial communication groove is formed in the inner surface of the hole, and the stop ring is removed from the slide hole at the inner surface end of the slide hole. While the snap ring to be prevented is fitted, a flow path constituted by the sliding hole and the seal ring, and a contact surface between the seal ring and the stop ring, and a radial groove formed in the seal ring. With the above seal ring up when cushioning. Contact, sandwiching the sealing ring between the stepped portion and the stop ring, the cushion device of the hydraulic cylinders constituting the gap between the stepped portion and the seal ring at the time of returning to the step portion inner surface.