JPH026277Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a hydraulic shock absorber mainly used in suspension systems of automobiles.

Usually, in the above-mentioned hydraulic shock absorber, the inside of the cylinder is oil-tightly partitioned into a piston upper chamber and a piston lower chamber by a piston that reciprocates within the cylinder. The piston is provided with piston ports and orifice ports that communicate with the upper and lower chambers of the piston at equal intervals on the same radius, and a thin ring-shaped non-return valve is fitted to the piston rod on the upper side of the piston. The non-return valve is urged toward the upper surface of the piston by a spring or the like, and the inner peripheral edge of the non-return valve covers a portion of the piston port. A ring-shaped non-return valve stopper is fixed to the piston rod above the non-return valve through a small gap. As shown in FIG. 5, the non-return valve has a claw 3 that locks the non-return valve 30 at a position facing the piston port 31.
2 are assembled in multiple locations. The claw 32 has a substantially rectangular shape, projects downward from the non-return valve stopper 33, contacts the inner peripheral edge of the non-return valve 30, and locks the non-return valve 30 against the piston port 31 to prevent it from slipping. It is. As the piston reciprocates, oil reciprocates between the piston upper chamber and the piston lower chamber through the piston port and the orifice port, and at this time, a damping force is generated by the throttling action at the piston port and the orifice port. Particularly on the expansion side, oil passes through the small gap between the non-return valve and the non-return valve stopper, descends from the gap in the non-return valve to the top surface of the piston, and flows into the piston port, where the damping force due to the throttling action is applied. Occur. However, when the pawl is assembled to the non-return valve stopper, since the pawl is located on the middle circumference where the piston port is provided, the pawl may block the piston port depending on the position where the pawl is installed, as shown in Figure 5. , the damping force may vary during an impact, and the reliability of the hydraulic shock absorber may be impaired.

The purpose of this invention is to provide a hydraulic shock absorber that generates a stable damping force against impact.

This invention will be explained below based on drawings showing embodiments. 1 and 2 show a first embodiment of this invention. In the figure, a hydraulic shock absorber 1 has an outer cylinder 2 and an inner cylinder 3 coaxial with the outer cylinder 2, and an auxiliary tank 4 is provided between the two cylinders.
A piston 5 is fitted into the inner cylinder 3 in a reciprocating manner in an oil-tight manner. The piston 5 is fitted into the lower small diameter portion 7 of the piston rod 6, and is fixed to the piston rod 6 via a spacer 8 with a mounting nut 9. The interior of the inner cylinder 3 is oil-tightly divided into an upper cylinder chamber 10 and a lower cylinder chamber 11 by the piston 5.

The piston 5 is provided with a piston port 12 that communicates between the upper and lower chambers 10 and 11 of the piston.
Outside the piston port 12 (but not on the same radius) are the upper and lower chambers 10 and 11 of the piston.
An orifice port 13 is provided that communicates with the. The piston port 1 is located on the upper surface 5a of the piston 5.
A ring groove 14 having a width larger than the cross-sectional area of the piston port 12 communicating with the piston port 2 and an appropriate depth is provided, and a ring-shaped protrusion 1 is formed on the outside of the ring groove 14.
5 is provided to slightly protrude above the upper surface 5a of the piston 5. A thin ring-shaped non-return valve 16 is placed on the projection 15 and loosely fitted into the piston 5. Non-return valve 1
The inner peripheral edge 16a of 6 covers a part of the piston port 12. A non-return valve stopper 18 is fixed to the step between the piston rod 7 and its lower small diameter portion 8 above the non-return valve 16 with a small gap 17 between it and the non-return valve 16. A pawl 19 is attached to the non-return valve stopper 18, and the pawl 19 projects downward, contacts the non-return valve 16, and locks the valve at a position facing the piston port 12. Note that the non-return valve 16 completely covers the upper opening of the orifice port 13.

A cylindrical main valve 20 having a flange 20a is slidably fitted on the outer peripheral surface 8a of the spacer 8, and a compression spring 21 is inserted between the flange 20a and the tightening nut 9. The flange 20a closes the lower opening of the piston port 12 when the piston 5 is at rest.

In the above configuration, on the extension side of the hydraulic shock absorber 1 (the state in which the piston 5 rises in FIG. 1), the oil pressure in the piston upper chamber 10 is greater than the oil pressure in the piston lower chamber 11, so the oil is absorbed by the spring force of the compression spring 21. The main valve 20 is pushed down against the pressure, and the piston flows into the lower chamber 11. At this time, the oil in the piston upper chamber 10 enters the ring groove 14 through the small gap 17 between the non-return valve 16 and the non-return valve stopper 18, and further flows into the piston port 12. When oil flows through the small gap 17, it flows radially from the outer periphery of the small gap 17 toward the piston rod 6, passes through the ring groove 14, and flows into the piston port 12, so the relative position between the piston port 12 and the pawl 19 changes. In other words, whether the pawl 19 is in a position that blocks the piston port 12 or not, the influence of the pawl 19 on the throttling action is always kept small, and the piston port 12 is always kept in a stable state. The oil will flow, and this will provide a stable damping force against impact. Incidentally, on the extension side of the hydraulic shock absorber 1, the orifice port 13 is closed by the non-return valve 16, so that no oil flows.

On the contraction side of the hydraulic shock absorber 1, that is, when the piston 5 descends, the pressure in the lower piston chamber 11 is greater than the pressure in the upper piston chamber 12, so the piston port 12
The lower opening of is the flange 20a of the main valve 20.
The oil moves from the lower piston chamber 11 to the upper piston chamber 10 via the orifice port 13.

FIGS. 3 and 4 show an embodiment of a technique that can achieve the same effects as this invention. The hydraulic shock absorber 31 of this embodiment has almost the same structure as the hydraulic shock absorber 1 of the first embodiment, but does not have the ring groove 14 of the hydraulic shock absorber 1, and instead has a groove on the piston top surface 5a side of the piston port 12. An enlarged opening 12a having a larger diameter than the piston port 12 is provided. Therefore, when the piston 5 moves up, the oil in the piston upper chamber 10 flows into the piston port 12 through the opening 12a, so even if there is a change in the relative position between the piston port 12 and the pawl 19, the pawl will not affect the throttling action. The piston port 12 is maintained in a small state, and oil always flows in a stable state to the piston port 12, so that a stable damping force against impact can be obtained. The rest of the structure of this embodiment is the same as that of the first embodiment, so the same components are given the same numbers and the explanation of their functions will be omitted.

As mentioned above, in this invention, a thin ring-shaped non-return valve is fitted into the piston rod above the piston having a piston port, and a ring-shaped non-return valve is inserted above the non-return valve through a small gap. The stopper is fixed to the piston rod, and the non-return valve is locked by a claw attached to the non-return valve stopper at a position facing the piston port.As the piston moves, oil flows through the piston port, and at that time oil flows at the piston port inlet. In a hydraulic shock absorber that generates a damping force against impact by a throttling action on the flow of oil, the piston is provided with a ring groove to stabilize the damping force, so a non-return valve and a non-return valve stopper are used. When assembling the non-return valve and non-return valve stopper to the piston rod, even if the position of the pawl relative to the piston port changes, the effect of the pawl on the throttling action is small and the damping force remains almost the same. It is no longer necessary to pay close attention to finding it as before,
Assembly man-hours are significantly reduced.

[Brief explanation of drawings]

FIG. 1 shows a longitudinal sectional front view of a main part of a first embodiment of this invention, and FIG. 2 is a view taken along the - line in FIG. 1. FIG. 3 shows a longitudinal sectional front view of a main part of an embodiment of the technology related to this invention, and FIG. 4 shows a view taken along the - line in FIG. 3. FIG. 5 is a perspective view showing an example of a manner in which the claw and the non-return valve are engaged. 1, 31... Hydraulic shock absorber, 2... Inner cylinder (cylinder), 5... Piston, 6... Piston rod, 10... Piston upper chamber, 11... Piston lower chamber, 12... Piston port, 13... ...Orifice port, 16...Non-return valve, 18
...Non-return valve stopper, 19...claw,
12a...Enlarged opening, 14...Ring groove.

Claims (1)

[Scope of utility model registration request] The inside of the cylinder is oil-tightly divided into an upper piston chamber and a lower piston chamber by a piston that reciprocates inside the cylinder, and the piston is provided with a piston port and an orifice port that communicate the upper and lower chambers,
A thin ring-shaped non-return valve is fitted onto the piston rod above the piston, and a ring-shaped non-return valve stopper is fixed to the piston rod through a small gap above the non-return valve. is locked by a claw attached to the non-return valve stopper at a position facing the piston port, and as the piston reciprocates, oil reciprocates between the piston upper chamber and the piston lower chamber through the piston port and orifice port, and at this time, the piston The hydraulic shock absorber generates a damping force against impact by a throttle action on the flow of oil at a port, and the hydraulic shock absorber is a hydraulic shock absorber that is located above the piston port on the top surface of the piston, communicates with the piston port, and circulates around the top surface of the piston. A hydraulic shock absorber comprising a ring groove having a predetermined width and an appropriate depth.