JPH0642139Y2 - Hydraulic cylinder seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention relates to a seal structure for a hydraulic cylinder used for a hydraulic shock absorber or the like for improving the riding comfort and steering stability of a vehicle, for example.

"Prior Art" As a conventional seal structure of this type, ones shown in FIGS. 4 and 5 are known. FIG. 4 shows an outline of the hydraulic shock absorber, which is the inner cylinder 1.
Inner cylinder 1 of double cylinder consisting of outer cylinder 2 and outer cylinder 2
A piston rod 4 is attached to a piston 3 slidably provided inside, and the piston rod 4 penetrates a rod guide 6 having a rod seal 5 provided at the upper part of the inner and outer cylinders, and a rod ring 7, and an outer cylinder. The upper part of 2 is projected to the outside.

The piston rod 4 is provided with a through hole 4a.
Pressure oil is supplied to and discharged from the outside of the oil chamber in the inner cylinder 1 via the 4a. An accumulator (not shown) filled with high-pressure gas is connected to the through hole 4a via a damping force generating valve (not shown), and acts between the piston rod 4 and the inner and outer cylinders 1 and 2. It is designed to damp vibrations. The space between the inner cylinder 1 and the outer cylinder 2 serves as a reservoir for storing a small amount of oil leaked between the piston rod 4 and the rod seal 5.

FIG. 5 is an enlarged view of the vicinity of the rod guide 6 described above. The ring-shaped groove 6a formed on the inner peripheral surface of the rod guide 6 is attached to the outer periphery of the piston rod 4 such as tetrafluoroethylene resin. And a rod seal 5 formed in a ring shape is provided on the outer peripheral surface of the rod seal 5.
A rubber O-ring 8 that is in close contact with the wall surface of 6a is fitted. A support member (pressure bearing plate) 9 that holds one end of the rod seal 5 and the O-ring 8 is provided on the end surface of the rod guide 6.

Reference numeral 12 is an annular bearing coated with fluorine resin or the like, and reference numeral 13 is a seal member that liquid-tightly seals between the rod guide 6 and the inner cylinder 1.

[Problems to be Solved by the Invention] However, in the above-described conventional hydraulic cylinder seal structure, since the rubber O-ring 8 is fitted on the outer periphery of the rod seal 5, the pressure in the inner cylinder 1 becomes O. By acting on the side surface of the ring 8 on the inner cylinder 1 side, the O-ring 8 is pressed by the support member 9 and extends in the radial direction (direction shown by the arrow in FIG. 5) to be deformed. Is pressed against the piston rod 4. Therefore, the rod seal 5
The friction between the piston rod 4 and the piston rod 4 increases. Further, there is a problem that the shape of the O-ring 8 is deformed as the pressure in the cylinder changes, and the friction also changes due to this, which deteriorates the riding comfort of the vehicle.

This invention was made in view of the above problems,
Even if a high pressure is applied to the outer circumference of the O-ring, the O-ring does not greatly expand in the radial direction and is deformed, and therefore the friction between the rod seal and the piston rod is not increased, and the hydraulic pressure is comfortable for the vehicle. It is intended to provide a seal structure for a cylinder.

[Means for Solving the Problem] In order to solve the above-mentioned problems, the present invention is provided between a cylinder filled with oil liquid and a piston rod movably provided so as to project from one end of the cylinder. And a seal groove forming member having a seal groove opening to the inner peripheral side is provided between the cylinder and the piston rod, and the seal groove is made of a resin that is fitted to the piston rod. An annular rod seal is provided, and a metal ring extending in the axial direction of the piston rod is provided on the outer peripheral side of the rod seal, and one end of the metal ring is pressed and supported by the side surface of the seal groove on the cylinder end side. An inner rubber seal that adheres to the outer peripheral surface of the rod seal is attached to the inner peripheral surface of the metal ring, and an outer rubber seal that adheres to the wall surface of the seal groove is attached to the outer peripheral surface of the metal ring. Is configured.

[Operation] As described above, in the seal structure of the present invention, the inner and outer rubber seals are attached to the inner and outer peripheral surfaces of the metal ring, and further, the end of the metal ring is pressed and supported by the side surface of the seal groove on the one end side of the cylinder. Even if the pressure in the cylinder acts from the side surface of the inner and outer rubber seals on the other end side of the cylinder, the metal ring is pressed and supported by the side surface of the seal groove on the one end side of the cylinder and is not deformed in the axial direction of the piston rod. , The inner and outer rubber seals attached to the inner and outer peripheral surfaces of the metal ring are less likely to be deformed (crushed) in the axial direction of the piston rod, and as a result, they may be deformed (crushed) in the axial direction more than necessary and expanded in the radial direction. To be prevented.

[Examples] Hereinafter, the present invention will be described with reference to the drawings. Figure 1,
FIG. 2 shows an embodiment of the seal structure of the hydraulic cylinder of the present invention, and FIG. 1 shows an enlarged sectional view of the vicinity of the rod guide of the hydraulic shock absorber shown in FIG. In these figures, the same components as those of the conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

A rod guide 6 fitted inside the outer cylinder 2 is provided at the upper end of the inner cylinder 1, and a piston rod 4 penetrates the inside of the rod guide 6. A ring-shaped groove 6 a is formed on the inner peripheral surface of the rod guide 6 between the rod guide 6 and the piston rod 4. A rod seal 5 fitted to the outer peripheral surface of the piston rod 4 is provided inside the groove 6a, and a rubber seal 10 is provided on the outer peripheral surface of the rod seal 5.

The rubber seal 10 is composed of an inner rubber seal 10a attached to the inside of the metal ring 11 by baking or bonding, and an outer rubber seal 10b attached to the outside of the metal ring 11 by baking or bonding. The inner peripheral surface of the inner rubber sheet 10a is in close contact with the outer peripheral surface of the rod seal 5, and the outer peripheral surface of the outer rubber seal 10b is in close contact with the wall surface of the groove 6a of the rod guide 6. The metal ring 11 is formed by a ring portion 11a extending parallel to the outer peripheral surface of the piston rod 4 (in the axial direction of the piston rod) and a side plate portion 11b bent in a direction orthogonal to the piston rod 4. It is a ring having an L-shaped cross section, and is formed at one end (first portion) of the ring portion 11a.
The upper side in the figure) is configured to be supported by a disc-shaped support member 9 provided on the upper surface side 6b of the rod guide 6.

Therefore, in this embodiment, the rod guide 6 and the support member 9 form a seal groove forming member, and the groove portion 6a of the rod guide 6 and the support member 9 form a seal groove.

Thus, the seal structure of the hydraulic cylinder of the present embodiment is
Since the inner rubber seal 10a and the outer rubber seal 10b are baked on the inner and outer surfaces of the metal ring 11 including the ring portion 11a and the side plate portion 11b, one end of the ring portion 11a is brought into contact with the support member 9, The pressure inside the cylinder is the inner and outer rubber seals 10a, 10
Even if it acts on the side surface of b from the lower side in the figure, the metal ring 11 is
The inner and outer rubber seals 10a and 10b are deformed (crushed) in the axial direction of the piston rod 4 because they contact the side surface (upper surface in the drawing) of the piston rod 4 and are pressed and supported without being deformed in the axial direction of the piston rod 4 (vertical direction in the drawing). Difficult, and thereby, it is prevented from being deformed (crushed) in the axial direction more than necessary and extending in the radial direction.

In the above embodiment, the metal ring 11 is a ring having an L-shaped cross section, but the present invention is not limited to this.
A side plate portion may be formed on the side contacting with to form a ring having a U-shaped cross section.

The ring portion 11a of the metal ring 11 extends parallel to the outer peripheral surface of the piston rod 4, but is not parallel if the rigidity is high, and extends along the outer peripheral surface of the piston rod 4 at a predetermined angle. But it doesn't matter. Further, although one end of the metal ring 11 directly contacts the side surface of the seal groove, the invention is not limited to this, and the inner and outer rubber seals 10a, 10b are not limited to this.
In manufacturing, when the one end is covered with a rubber member connecting the two, the one end may indirectly contact the side surface of the seal groove via the rubber member.

Next, a second embodiment will be described with reference to FIG. In the second embodiment, in the seal structure of the hydraulic cylinder shown in the first embodiment, a seal groove forming member 14 is provided on the upper portion of the rod guide 6 as a separate body, and the seal groove forming member 14 is provided.
A rod seal 5 is provided in a groove portion 14a formed on the inner peripheral surface of the metal ring, and a metal ring 11 to which inner and outer rubber seals 10a and 10b are attached is provided on the outer peripheral surface thereof, and an end surface of the metal ring 11 is formed into a seal groove forming member. The end face of the groove 14a of 14 is received.

Therefore, also in the second embodiment, the same effect as that of the first embodiment can be obtained.

[Advantages of the Invention] As described above, the present invention provides a seal structure provided between a cylinder filled with oil liquid and a movably provided piston rod protruding from one end of the cylinder. A seal groove forming member having a seal groove opening to the inner peripheral side is provided between the cylinder and the piston rod,
A resin-made annular rod seal fitted to the piston rod is provided in the seal groove, the rod seal extends on the outer peripheral side in the axial direction of the piston rod, and one end portion of the seal groove is on the cylinder end side. A metal ring that is pressed and supported on the side surface of the metal ring, an inner rubber seal that adheres to the outer peripheral surface of the rod seal is attached to the inner peripheral surface of the metal ring, and the seal groove is formed on the outer peripheral surface of the metal ring. Since the outer rubber seal that adheres closely to the wall surface of the cylinder is attached, even if the pressure inside the cylinder acts from the side surface on the other end side of the cylinder of the inner and outer rubber seals, the metal ring is The inner and outer rubber seals attached to the inner and outer peripheral surfaces of the metal ring are not deformed (crushed) in the axial direction of the piston rod because they are pressed and supported by the side surface and do not deform in the axial direction of the piston rod. Thereby deformed in the axial direction more than necessary Te (collapse), since it is prevented from extending in the radial direction, an effect that can prevent an increase in friction of the rod seal.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention,
FIG. 1 is an enlarged sectional view near the rod guide, FIG. 2 is a sectional view of a seal member, FIG. 3 is an enlarged sectional view near the rod guide showing the second embodiment, and FIGS. FIG. 4 is a view showing the technique of FIG. 4, and FIG. 4 is a side sectional view of the entire hydraulic shock absorber,
FIG. 5 is an enlarged cross-sectional view near the rod guide. 1 ... Inner cylinder, 2 ... Outer cylinder, 4 ... Piston rod, 5 ... Rod seal, 6a ... Groove, 8 ... O-ring, 9 ... Support member, 10a ... Inner rubber seal, 10b ...
Outer rubber seal, 11 …… Metal ring.

Claims (1)

[Scope of utility model registration request] 1. A seal structure provided between a cylinder filled with oil liquid and a piston rod movably provided so as to project from one end of the cylinder, the seal structure being provided between the cylinder and the piston rod. Is provided with a seal groove forming member having a seal groove opening to the inner peripheral side, the seal groove is provided with a resinous annular rod seal fitted to the piston rod, and the piston rod is provided on the outer peripheral side of the rod seal. A metal ring that extends in the axial direction of the seal ring and one end of which is pressed against and supported by the side surface of the seal groove on the cylinder end side, and the inner peripheral surface of the metal ring is in close contact with the outer peripheral surface of the rod seal. A seal structure for a hydraulic cylinder, characterized in that an inner rubber seal is attached, and an outer rubber seal that adheres to the wall surface of the seal groove is attached to the outer peripheral surface of the metal ring.