JP4671526B2 - Shock absorber - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a shock absorber used for seismic isolation, for example.
[0002]
[Prior art]
FIG. 2 shows a conventionally known shock absorber for seismic isolation.
The conventional shock absorber includes a first cylinder tube 1 and a second cylinder tube 2 located outside the first cylinder tube 1, and forms a space between the tubes 1 and 2. The first cylinder tube 1 has its one end 1 a fitted to the rod side closing member 3. On the other hand, the other end 1b is fitted to the bottom closing member 4 via a main body VB of a third damping valve 14 to be described later.
[0003]
Moreover, the 2nd cylinder tube 2 is fixing the both ends as follows.
That is, the ring-shaped connecting member 5 is fixed to the outer periphery of the rod side blocking member 3, and the second cylinder tube 2 is fitted to the outer periphery of the connecting member 5, and the fitting portion is fixed by welding. Further, the other end 2a of the second cylinder tube 2 is directly fitted into the bottom-side closing member 4, and the fitted portion is fixed by welding.
[0004]
A piston 6 is slidably incorporated in the inner circumference of the first cylinder tube 1 as described above, and a piston rod 7 that moves integrally with the piston 6 is provided on the piston 6. The piston rod 7 is slidably supported in the rod hole 8 of the rod side blocking member 3 and protrudes outward from the blocking member 3.
The piston 6 partitions the inside of the first cylinder tube 1 into a rod side chamber 9 and a bottom side chamber 10.
[0005]
Furthermore, the piston 6 is provided with a first damping valve 11 and a second damping valve 12 that communicate the rod side chamber 9 and the bottom side chamber 10. The first damping valve 11 permits only the oil flow from the rod side chamber 9 to the bottom side chamber 10, and the second damping valve 12 permits only the oil flow from the bottom side chamber 10 to the rod side chamber 9. Therefore, the first damping valve 11 functions when the piston 6 moves in the direction of reducing the volume of the rod side chamber 9, and the second damping valve 12 functions when the piston 6 moves in the direction of reducing the bottom side chamber 10. .
[0006]
Further, a space formed between the first cylinder tube 1 and the second cylinder tube 2 is a tank 13, and the tank 13 and the bottom side chamber 10 are communicated with each other via a third damping valve 14. The third damping valve 14 allows the flow from the bottom chamber 10 to the tank 13 and generates a damping force when the flow occurs. Further, a check valve 16 that allows only the flow from the tank 13 to the bottom side chamber 10 is provided between the tank 13 and the bottom side chamber 10.
[0007]
Therefore, when the piston 6 moves in the direction of expanding the bottom side chamber 10, the oil in the rod side chamber 9 is pushed out to the bottom side chamber 10 via the first damping valve 11. However, since the volume of the bottom side chamber 10 is larger by the moving body integral of the piston rod than the rod side chamber 9, the amount of oil in the bottom side chamber 10 is insufficient by the moving body integral of the piston rod. At this time, the oil in the tank 13 pushes open the check valve 16 and flows into the bottom chamber 10 to compensate for the shortage.
[0008]
On the other hand, when the piston 6 moves in the direction of reducing the bottom side chamber 10, the oil in the bottom side chamber 10 flows into the rod side chamber 9 via the second damping valve 12 as described above. However, the volume of the rod side chamber 9 is smaller than the volume of the bottom side chamber 10 by the moving body integral of the piston rod 7. Therefore, the total amount of oil in the bottom side chamber 10 cannot flow into the rod side chamber 9 in the above case, but excess oil at this time is returned to the tank 13 via the third damping valve 14 described above. .
[0009]
Further, the tank 13 and the rod side chamber 9 are communicated with each other through a passage 15 formed in the rod side closing member 3. The passage 15 is a passage for removing air that has entered the rod side chamber 9 and the bottom side chamber 10 when oil is filled therein.
[0010]
The operation of the conventional shock absorber as described above will be described.
When the piston rod 7 is moved to the left side from the position of FIG. 2 by an external force, the piston 6 is moved to the left side integrally therewith. When the piston 6 moves to the left side, the oil in the rod side chamber 9 is pushed out to the bottom side chamber 10 via the first damping valve 11. However, since the volume of the bottom side chamber 10 is larger by the moving body integral of the piston rod than the rod side chamber 9, the amount of oil in the bottom side chamber 10 is insufficient by the moving body integral of the piston rod. Therefore, the oil in the tank 13 flows into the bottom side chamber 10 via the check valve 16 to compensate for the shortage on the bottom chamber side 9.
[0011]
Thus, when the oil in the rod side chamber 9 flows into the bottom side chamber 10 via the first damping valve 11, a damping force is exhibited and the movement of the piston 6 is buffered. Therefore, in the case of the seismic isolation device, the vibration caused by the earthquake is absorbed.
[0012]
On the other hand, when the piston rod 7 moves to the right side in FIG. 2, the piston 6 also moves to the right side. When the piston 6 moves to the right side, the oil in the bottom side chamber 10 pushed out by the piston 6 flows into the rod side chamber 9 through the second damping valve 12.
However, since the volume of the rod side chamber 9 is smaller than the bottom side chamber 10 by the moving volume of the piston rod, the oil in the bottom side chamber 10 pushed out by the piston 6 cannot flow into the rod side chamber 9. . Therefore, the oil that cannot flow in flows into the tank 13 through the third damping valve 14.
[0013]
Thus, when the piston 6 moves to the right side, the oil in the bottom side chamber 10 flows into the rod side chamber 9 via the second damping valve 12, and the oil that could not flow into the rod side chamber 9 is the third damping valve. It flows into the tank 13 through 14. As described above, the oil passes through the second damping valve 12 and the third damping valve 14 to exert a damping force, and the movement of the piston rod 7 due to the external force is buffered.
Thus, when the piston 6 moves to the left or right, the movement of the piston rod 7 due to the external force is buffered, and the vibration caused by the earthquake can be absorbed as described above.
[0014]
[Problems to be solved by the invention]
In the conventional shock absorber, when an external force is applied and a high pressure is applied in the rod side chamber 9 or the bottom side chamber 10, a strong pulling force in the direction in which the rod side closing member 3 and the bottom side closing member 4 are separated from each other. Will occur. The generated tensile force acts on the second cylinder tube 2.
[0015]
As described above, a strong tensile force acts on the second cylinder tube 2, but the tensile force does not act on the first cylinder tube 1. This is because the first cylinder tube 1 is merely fitted to the closing members 3 and 4 at both ends.
For this reason, the second cylinder tube 2 needs to have sufficient strength to withstand even when a strong tensile force is applied.
[0016]
Moreover, if the second cylinder tube 2 is sufficiently thick as described above to ensure its strength, it is not true that the thickness of the first cylinder tube 1 can be reduced. This is because high pressure acts on the first cylinder tube 1 or bending stress acts on the first cylinder tube 1 due to sliding of the piston rod 7.
After all, in the case of the conventional shock absorber, both the first cylinder tube 1 and the second cylinder tube 2 must be thickened. For this reason, there is a problem that the entire weight is extremely increased and the shock absorber itself is increased in size.
An object of the present invention is to provide a shock absorber capable of maintaining a sufficient strength without increasing the overall weight.
[0017]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a piston slidably incorporated in a first cylinder tube, a piston rod that moves integrally with the piston, a bottom side chamber and a rod side chamber defined by the piston, and the first cylinder tube. A closing member closing both ends, a second cylinder tube positioned outside the first cylinder tube and held by the closing member, and a tank provided between the first cylinder tube and the second cylinder tube; And both ends of the first cylinder tube are directly coupled to the closing member by connecting means, the thickness of the first cylinder tube is increased, and the thickness of the second cylinder tube is decreased relative to the first cylinder tube. Thus, the external force is received by the first cylinder tube.
[0018]
The second invention is characterized in that the connecting means for coupling the first cylinder tube and the closing member comprises a screw.
The third invention is characterized in that the connecting means for joining the first cylinder tube and the closing member is made of welding.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows an embodiment of the present invention. This embodiment is characterized in that one end 17a of the first cylinder tube 17 is firmly connected to the rod-side closing member 19 and the other end 17b is firmly connected to the bottom-side closing member 20 via connecting means. The second cylinder tube 18 can be made sufficiently thinner than the first cylinder tube 17 by coupling the first cylinder tube 17 with connecting means. About the structure of those other than the said characteristic, it is the same as that of a prior art example. About the same component, the same code | symbol as a prior art example is used, The description is abbreviate | omitted.
[0020]
In this embodiment, one end 17a of the first cylinder tube 17 is directly coupled to the rod-side closing member 19 by connecting means. Further, the other end 17b of the first cylinder tube 17 is directly coupled to the bottom-side closing member 20 by connection means. In this embodiment, the connecting means is constituted by a screw.
Thus, since the 1st cylinder tube 17 is combined with each closure member 19 and 20 with a screw, even if a tensile force acts on the 1st cylinder tube 17, it does not come out. That is, the coupling force between the first cylinder tube 17 and the closing members 19 and 20 can be further strengthened.
[0021]
A nut member 21 is connected to the rod side closing member 19, and a cap 22 is connected to the bottom side closing member 20. The nut member 21 and the cap 22 are used as a connecting member for connecting the second cylinder tube 18. And after connecting the other end 18b of the 2nd cylinder tube 18 to the cap 22, the nut member 21 is connected to the 1st end 18a so that this 2nd cylinder tube 18 may be pinched | interposed. The second cylinder tube 18 is held by tightening the nut member 21. Therefore, the second cylinder tube 18 is merely fitted with the nut member 21 and the cap 22.
[0022]
In addition, two third damping valves 23 and 23 are provided between the bottom side chamber 10 and the tank 13. The third damping valves 23 and 23 are configured to allow only the oil flow from the bottom side chamber 10 to the tank 13 and generate a damping force when the flow occurs. Further, a check valve 24 is provided between the bottom side chamber 10 and the tank 13. This check valve 24 allows only the oil flow from the tank 13 to the bottom side chamber 10.
[0023]
The rod-side closing member 19 is provided with a passage 25 that is normally closed by a sealing member 25a, and one end of the passage 25 is opened to the rod-side chamber 9 and the other end is opened to the outside of the shock absorber S. ing. In addition, the bottom-side closing member 20 is provided with a passage 26 that is normally closed with a sealing member 26a. ing. The passages 25 and 26 are passages for removing the air that has entered the chambers 9 and 10 after the rod side chamber 9 and the bottom side chamber 10 are filled with oil.
[0024]
In the shock absorber S of the embodiment as described above, when the piston rod 7 moves to the left side from the position of FIG. 1 due to external force, the oil in the rod side chamber 9 flows into the bottom side chamber 10 via the first damping valve 11. At this time, the first damping valve 11 exhibits a damping force, and the movement of the piston 6 is buffered.
On the other hand, when the piston rod 7 moves to the right in FIG. 1, the oil in the bottom side chamber 10 flows into the rod side chamber 9 through the second damping valve 12, and the oil that could not flow into the rod side chamber 9 is the third. It flows into the tank 13 through the damping valves 23 and 23. In this manner, the oil passes through the second damping valve 12 and the third damping valves 23 and 23 to exert a damping force, and the movement of the piston rod 7 due to the external force is buffered.
If the movement of the piston rod 7 is buffered in this way, in the case of a seismic isolation device, the vibration caused by the earthquake is absorbed.
[0025]
Furthermore, according to this embodiment, since the first cylinder tube 17 is directly connected to the rod side closing member 19 and the bottom side closing member 20 with screws, it is assumed that a tensile force acts on the first cylinder tube 17. But it won't come off. That is, the coupling force between the cylinder tube 17 and the closing members 19 and 20 can be further strengthened.
Further, since bending stress acts on the first cylinder tube 17 by sliding of the piston rod 7, it is usual to give strength to endure this. Therefore, the first cylinder tube 17 is thick and has high strength. Thus, since the 1st cylinder tube 17 is equipped with high intensity | strength, even if a tensile force acts on this, it can fully endure.
[0026]
As described above, since the first cylinder tube 17 can receive a strong tensile force generated by the high pressure acting in the rod side chamber 9 or the bottom side chamber 10, it is necessary to receive the tensile force on the second cylinder tube 18. Absent. Since the second cylinder tube 18 does not need to receive a pulling force, the second cylinder tube 18 does not have to be thick as in the related art. That is, it is sufficient for the second cylinder tube 18 to be able to prevent oil leakage from the tank 13. Therefore, the second cylinder tube 18 can be made thin and the tensile force does not act, so that it is not necessary to firmly bond both ends thereof. As described above, since it is not necessary to firmly connect both ends of the second cylinder tube 18, it is possible to employ a configuration in which the nut member 21 and the cap 22 are fitted as in this embodiment.
[0027]
In this embodiment, since the second cylinder tube 18 can be made thin, the weight of the entire shock absorber does not increase, and the shock absorber itself can be reduced in size. In addition, since the first cylinder tube 17 can receive a tensile force, it is possible to maintain a sufficient strength against the tensile strength.
[0028]
In this embodiment, the bottom chamber 10 and the tank 13 are connected by the two third damping valves 23, 23, but this is not limited to two. That is, the third damping valve only needs to be able to generate a damping force with respect to the oil flowing into the tank 13 from the bottom side chamber 10.
Further, the bottom-side closing member 20 and the cap 22 may be integrated.
Further, the first cylinder tube 17 and the closing members 19 and 20 are coupled by using screws as connection means. However, they may be coupled by welding or other connection means may be used. Good.
[0029]
【The invention's effect】
According to the first to third aspects of the invention, the second cylinder tube is provided outside the first cylinder tube, and the first cylinder tube is coupled to the closing member by the connecting means. Therefore, the second cylinder tube is thinned. Thus, the weight of the entire shock absorber can be reduced by the amount that the second cylinder tube is thinned, and the shock absorber itself can be reduced in size. In addition, since the first cylinder tube can receive a tensile force, it is possible to maintain a sufficient strength against this tensile strength.
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of the present invention.
FIG. 2 is a view showing a conventional shock absorber.
[Explanation of symbols]
S shock absorber 6 piston 7 piston rod 9 rod side chamber 10 bottom side chamber 13 tank 17 first cylinder tube 18 second cylinder tube 19 rod side closing member 20 bottom side closing member 21 nut member 22 cap

Claims (3)

A piston slidably incorporated in the first cylinder tube, a piston rod that moves integrally with the piston, a bottom side chamber and a rod side chamber defined by the piston, and a closing member that closes both ends of the first cylinder tube And a second cylinder tube located outside the first cylinder tube and held by the closing member, and a tank provided between the first cylinder tube and the second cylinder tube, Both ends of the cylinder tube are directly coupled to the closing member by the connecting means, the thickness of the first cylinder tube is increased, the thickness of the second cylinder tube is decreased with respect to the first cylinder tube, and the first external force is applied. A shock absorber configured to be received by a cylinder tube.   The shock absorber according to claim 1, wherein the connecting means for connecting the first cylinder tube and the closing member comprises a screw.   The shock absorber according to claim 1, wherein the connecting means for joining the first cylinder tube and the closing member comprises welding.

Images