JPH0218325Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Field of Industrial Application The present invention relates to a cushion ring for a hydraulic cylinder, and more specifically to a cushion ring with an alignment function.

(B) Conventional technology When a lateral load (arrow) is applied as shown in Fig. 5, the cushion ring in a conventional hydraulic cylinder causes the piston rod 1 and the bearing 2, and the piston 3 and the cylinder tube 4 to move as shown in Fig. 6. Due to the play between them, the piston rod 1 and the cylinder tube 4 are in a relatively inclined state, and in the cushion stroke when the hydraulic cylinder is fully extended, the outer peripheral surface of the cushion ring 5 and the inner surface of the housing locally come into contact. Seizing or galling may occur.

(c) Problems to be solved by the invention As mentioned above, the conventional hydraulic cylinder had the drawback of seizing and galling caused by lateral loads acting on the hydraulic cylinder.

(d) Means for solving the problem Therefore, in the present invention, the cushion ring is loosely fitted to the piston rod with a gap, and
A protruding support part is provided on either the inner surface of the cushion ring or the outer surface of the piston rod, and is located approximately in the center of the cushion ring, and supports the cushion ring in a swingable manner on the piston rod. A sealing member is interposed between the cushion ring and the piston rod.

(E) Effect In the present invention having the above-described configuration, if friction is generated between the cushion ring and the inner surface of the housing during the cushion stroke of the hydraulic cylinder, the cushion ring swings about the fulcrum rib. Since the cushion ring is used for movement and is parallel to the inner surface of the housing, there will be no seizure or galling between the cushion ring and the inner surface of the housing.

(f) Embodiment FIGS. 1 to 3 show a state in which the hydraulic cylinder is in the compression stroke reaching the maximum extension state.

A piston 3 sliding within a cylinder tube 4 is fastened to a piston rod 1 with a nut 3, and a small diameter portion 1' is formed on the outer periphery of the piston rod 1 on the piston side.

A cushion ring 5 shown in FIG. 2 is fitted into the small diameter portion 1'. The cushion ring 5
When the hydraulic cylinder reaches its maximum extension, it fits into the housing 6 as shown in the figure, and connects the inner surface of the housing 6 and the cushion ring 5 to connect the oil flow path from the cylinder tube 4 to the tank side through the housing 6.
By restricting the flow path to an annular flow path 6' consisting of the outer periphery, a cushion mechanism is formed to reduce the impact when the hydraulic cylinder is fully extended.

On the other hand, a fulcrum rib 10 is protruded near the approximate center of the cushion ring 5 in the direction of its inner circumferential axis, and abuts on the outer periphery of the small diameter portion 1' on the piston rod side. Therefore, the cushion ring 5 can swing about the fulcrum rib 10 with respect to the piston rod 1, for example,
Even when the piston rod 1 extends in a tilted state with respect to the inside of the housing 6 as shown in FIG. 1, the cushion ring 5 is fitted parallel to the housing 6 due to the rocking action of the fulcrum rib 10, so seizure may occur. No galling or galling occurs. In addition, a seal ring 11 is fitted to the abutting portion of the fulcrum rib 10 against the small diameter portion 1' to suppress the pressure acting on the inner peripheral surface of the cushion ring 5.
prevents it from expanding. That is, in the case of the conventional device shown in FIG. 7 in which the cushion ring 5 is simply fitted into the small diameter portion 1' on the piston rod side, the pressure distribution acting on the cushion ring 5 during the cushion stroke is distributed around the outer periphery as shown by the arrow. A triangular pressure distribution occurs on the surface, while a rectangular pressure distribution acts on the inner peripheral surface.

This is because when the cushion ring 5 enters the cushion stroke, the hydraulic pressure inside the cylinder tube 4 pushes the cushion ring 5 toward the left in the diagram, and its tip is strongly pressed against the stepped portion of the piston rod 1, sealing that part. Therefore, the hydraulic pressure in the cylinder tube 4 is generated when it passes between the piston 3 and the cushion ring 5 and acts on the inner circumferential surface of the cushion ring 5. Then, a pressure distribution as shown in Figure 8 acts on the cushion ring 5, causing an outward bulge as shown by the broken line, which promotes seizure or galling between the cushion ring 5 and the housing inner surface 6. I will do it. However, when the seal ring 11 is fitted to the fulcrum rib 10 as in this embodiment, the pressure distribution acting on the inner peripheral surface of the cushion ring 5 does not occur to the left of the seal ring 8 in the drawing, as shown in FIG. A pressure distribution occurs on the right side of the drawing, but a larger pressure distribution also occurs on the outer circumferential side of the cushion ring 5 as it gets closer to the piston 3.
The bulge can be suppressed by the pressure balance between the inner and outer circumferences of the cushion ring 5, and when compared with the conventional device shown in Figs. 7 and 8, the pressure acting on the cushion ring 5 can be significantly reduced as shown in Fig. 4. Deformation can be avoided.

FIG. 2B shows another embodiment of the present invention in which a fulcrum rib 10 is provided protruding from the small diameter portion 1'. Also, the second
Figures C and D show the case where the fulcrum rib 8 is fitted onto and brought into contact with either the cushion ring 5 or the small diameter portion 1'.

(G) As described above, according to the present invention, the friction between the cushion ring 5 and the inner surface of the housing 6 due to the lateral load on the hydraulic cylinder is By tilting the cushion ring 5 using the fulcrum rib 10 provided between the cushion ring 5 and the housing 5 as a fulcrum, the cushion ring 5 can be automatically made parallel to the inner surface 6 of the housing and removed, which is of practical benefit. Very noticeable.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view showing an embodiment of a hydraulic cylinder equipped with the cushion ring of the present invention, Fig. 2 A is an enlarged sectional view showing the main parts of the cushion ring, and Figs. is an enlarged sectional view showing another embodiment of the cushion ring, FIGS. 3 and 4 are explanatory diagrams showing the pressure distribution acting on the same cushion ring, and FIG. 5 is a partially cutaway view showing a conventional hydraulic cylinder. FIG. 6 is a partially cutaway enlarged side view showing the operation of the cushion ring portion, and FIGS. 7 and 8 are explanatory views showing the pressure distribution in the cushion ring. 1...Piston rod, 2...Bearing, 3...Piston, 4...Cylinder tube, 5...Cushion ring, 6...Inner surface of housing, 11...Seal ring.

Claims (1)

[Scope of utility model registration request] In a hydraulic cylinder in which a cushion ring is provided at the end of the piston rod adjacent to the piston,
The cushion ring is loosely fitted onto the piston rod with a gap, and the cushion ring is fitted onto the piston rod approximately at the center of the cushion ring and either on the inner surface of the cushion ring or on the outer surface of the piston rod. 1. A cushion ring with an alignment function, characterized in that a protruding support part that is swingably supported is provided, and a sealing member is interposed between the cushion ring and the piston rod in the support part.