JPS6142988Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a piston mounting structure for a stay damper etc. that supports a back door of a vehicle, and more specifically, a piston assembled to allow a non-return valve to be normally installed between the piston and a valve stopper. Regarding the mounting structure.

Conventionally, when installing this type of piston to a piston rod, a ring-shaped valve stopper, a non-return valve, and a piston with an oil hole are sequentially inserted into the narrow diameter part of the lower part of the piston rod, and the lower end of the piston rod is connected to the lower end surface of the piston. the valve stopper, and the caulked portion and the stepped surface of the lower narrow diameter portion of the piston rod
It is designed to hold a non-return valve and piston.

However, when the non-return valve is inserted, there is a play in the radial direction and it is not held in the normal position, so when the piston is assembled, the non-return valve is sandwiched between the valve stopper and the piston. Because of this, the non-retardation valve cannot move up and down, and the piston's oil hole and orifice remain open, resulting in poor damping force.

The present invention improves these conventional drawbacks,
A ring-shaped non-return valve, whose two surfaces are overlapped at the stepped cut end so that they are flat, is attached to the piston boss between the piston and the valve stopper, which is pre-installed on the end of the piston rod, so that it can be freely displaced in the axial direction of the piston. By installing from the outer circumferential direction, this non-return valve is reliably prevented from being caught between the valve stopper and the piston when the non-return valve is assembled, and damping force characteristics with stable performance are always obtained. Provides a piston mounting structure.

Embodiments of the present invention will be specifically described below based on the drawings.

FIG. 1 is a sectional view showing a piston mounting structure. In the figure, reference numeral 1 denotes a piston rod, through which a through hole 2a of a valve stopper 2 is inserted into a small diameter portion 1a at the tip thereof, and adjacent to this is a piston 3 having a boss portion 3a and three oil holes 3b. Through hole 3
The valve stopper 2 and the piston 3 are firmly held on the piston rod 1 by caulking the end of the narrow diameter portion 1a. Note that 4 is a caulking member.

The valve stopper 2 is provided with a plurality of, for example, three notches 2b at equal intervals so as to open on the outer periphery, and the valve stopper 2 may be formed of an elastic plate made of resin or the like.

3, 4 and 5 show a ring-shaped non-return valve 5 made of an elastic plate, a part of which is cut and the cut ends have stepped portions 5a, 5b.
is formed. This non-return valve 5 is attached to the piston boss portion 3a of the piston 3 that has already been assembled.
Then, the stepped portions 5a and 5b are opened and bent as shown in FIG. 4, and the stepped portions 5a and 5b are inserted and fitted from a direction substantially perpendicular to the axial direction. Such an inserted non-return valve 5 is caused by its own resiliency or by the pressure of the working fluid at its cut end so that the two faces are in the first position.
As shown in Fig. 5, they are mutually flatly polymerized.

On the other hand, the piston 3, as shown in FIG.
A recess 8 surrounded by two protrusions 6 and 7 having ring-shaped seat surfaces is provided on the side surface facing the non-return valve 5, and the oil passage hole 3b is provided in the recess 8. One end of the world is approaching. In addition, the oil passage hole 3b
An orifice notch 9 communicating with the recess 8 and the inner periphery of the piston 3 is provided on the radially inner protrusion 6 facing the piston 3 . Furthermore, a gap 10 is provided between the boss portion 3a and the protrusion 6 in the inner diameter direction facing the oil passage hole 3b, which forms a relatively free working fluid passage during compression operation.
is provided.

Note that the through hole 5 at the center of the non-return valve 5
c is formed in such a size that it is larger than the outer diameter of the boss portion 3a, and the vicinity of the through hole 5c is reliably supported on the protrusion 6. Moreover, the notch 2b provided in the valve stopper 2 is
The through hole 5c of the non-return valve 5 is opened to ensure a free flow in the inner periphery during compression operation.

In the piston mounting structure configured in this way, when the piston rod 1 moves in the extension direction, the non-return valve 5 receives the working fluid pressure.
is pressed against the side surface of the piston 3, and the recess 8
It acts to block the Therefore, the working fluid sequentially passes through the orifice notch 9 of the piston 3 and the oil passage hole 3b and moves to the negative pressure chamber side of the cylinder. That is, in the elongation direction, a damping force characteristic corresponding to the immediate cross-sectional area of the orifice notch 9 is obtained.

On the other hand, when the piston rod 1 moves in the contraction direction, the working fluid in the high pressure chamber passes through the oil passage hole 3b of the piston 3 and reaches the recess 8, and then the notch 1
0. The gap between the boss portion 3a and the through hole 5c of the non-tarin valve 5 and the notch 2b of the valve stopper 2
In addition to moving to the negative pressure chamber side through each of them, a small amount also moves from the recess 8 through the outer periphery of the non-return valve 5. In this way, the piston rod 1 can be pushed into the cylinder with the damping force almost zero.

In this way, this piston mounting structure reliably performs the desired damping force generation operation, but when assembling it, the non-return valve is simply bent and inserted into the piston boss section from the side. Therefore, the assembly work is facilitated and speeded up, and the occurrence of jamming between the valve stopper and the piston during assembly, which is conventional, can be completely prevented.

FIGS. 7 and 8 show another embodiment of the present invention in which the free flow during compression operation is in the form of a peripheral flow. In the same figure, 11 is a piston, and the surface of this piston 11 facing the non-return valve 5 has two ring-shaped protrusions 12, 1 having a seat surface.
3 are provided, and a recess 14 communicating with the oil passage hole 11b is provided between these. Note that 11a is a boss portion of the piston 11. Reference numeral 15 denotes a valve stopper, and three notches 15b opening on the outer periphery are formed shallower in the center direction than the notches 2b of the valve stopper 2 described above. Note that 15a is a through hole in the center of the valve stopper 15, and 16 is a hole in the center of the valve stopper 15.
This is an orifice cutout formed in the.

In such an implementation structure, the movement of the piston rod 1 in the extension direction is similar to that described above, but when the piston rod 1 moves in the contraction direction, the working fluid from the high pressure chamber side flows to the piston 11 through the oil passage hole 11b. and reaches into the recess 14, and then the protrusion 1
2 and the outer periphery of the non-return valve 5, and moves from the notch 15b of the valve stopper 15 to the negative pressure chamber side. In this way, the piston rod 1 can be pushed into the cylinder with the damping force almost zero.

As explained above, according to the present invention, a ring-shaped non-return valve that is separably overlapped at the stepped cut end and has two flat surfaces is connected to the valve stopper that is pre-installed on the piston rod end. By inserting and fitting the non-return valve into the piston boss section between the piston from a direction substantially perpendicular to the central axis, the installation work of the non-return valve is facilitated, and the non-return valve is inserted between the piston and the valve stopper when installing the piston. Accidents such as the return valve becoming jammed are eliminated, and stable damping force characteristics can always be obtained.

In addition, since the cut ends of the non-return valve overlap each other when the piston moves in the extension direction, even if this part faces the orifice cutout or oil passage hole,
No leakage of hydraulic oil occurs at this overlapping portion, and therefore no rotation prevention means or positioning means for the non-return valve are required, and the damping force characteristics are not deteriorated.

Furthermore, by making the outer diameter of the non-return valve slightly larger than the inner diameter of the cylinder, it can also be made to function as a piston ring.

Furthermore, by utilizing the change in outer diameter of the non-return valve due to temperature, it can be applied to applications where the damping force is lowered at low temperatures and increased at high temperatures.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the piston mounting structure according to the present invention, Fig. 2 is a plan view showing the relationship between the piston and the valve stopper, Fig. 3 is a plan view of the non-return valve, and Fig. 4 is a perspective view. FIG. 5 is a front view when the cut ends are overlapped, FIG. 6 is a perspective view of a modified assembly, FIG. 7 is a plan view showing another embodiment, and shows the relationship between the piston and the piston valve, and FIG. FIG. 2 is an assembled perspective view of another embodiment. 1... Piston rod, 2, 15... Valve stopper, 2b, 15b... Notch, 3, 11... Piston, 3a, 11a... Piston boss portion, 3
b, 11b...Oil hole, 5...Non-return valve, 5a, 5b...Cut end, 6, 12...Protrusion on the outer diameter side, 7, 13...Protrusion on the inner diameter side, 8, 14
... recess, 9 ... orifice notch, 10 ... notch.

Claims (1)

[Claims for Utility Model Registration] (1) A piston boss between the piston and a valve stopper attached to the end of the piston rod, which is a non-return valve that is separably overlapped at the cut end and has two flat surfaces. A piston mounting structure in which the non-return valve is inserted into the piston from the outer radial direction thereof and is supported by the piston boss portion so as to be freely displaceable in the axial direction. (2) Claim 1 of the utility model registration, in which the non-return valve is formed of an elastic material in a spiral shape.
Piston mounting structure described in section. (3) Two ring-shaped protrusions having a seat surface are provided through a recess on the side surface of the piston facing the non-return valve, and within the recess are oil holes penetrating both sides of the piston. 2. The piston mounting structure according to claim 1, wherein an orifice notch is provided in the protrusion on the inner diameter side or the outer diameter side. (4) A gap is formed between the outer periphery of the non-return valve fitted into the piston boss portion, the inner periphery of the cylinder, and the outer diameter protrusions on the end surface of the piston, through which the working fluid passes during compression operation. A piston mounting structure according to claim 1 of the utility model registration claim. (5) A request for utility model registration in which the valve stopper is provided with a notch that opens on its outer periphery, and a portion of this notch is formed to a size that covers the central through-hole of the non-return valve in the assembled state. The piston mounting structure described in range 1. (6) The piston mounting structure according to claim 1, wherein the outer diameter of the non-return valve is formed to be somewhat larger than the inner diameter of the cylinder.