JP2004028188A - Hydraulic damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic damper surely clamping a piston so as not to be loosened when a piston and a pair of piston rods are assembled in the both rods type hydraulic damper. <P>SOLUTION: This hydraulic damper is provided with the piston 6 retained by being clamped between the two piston rods 10a and 10b. The piston 6 is retained by removing a clearance between one piston rod 10b and the piston 6 formed when a prescribed value or more tensile load is applied to the other piston rod 10a, with the tensile load applied thereto. Because the piston is surely clamped between the pair of piston rods so as not to be loosened, the loosening of the fixing of the piston clamped between the piston rods when the hydraulic damper is damped can be prevented. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a double rod type hydraulic damper in which a piston rod projects on both axial sides of a piston, and more particularly to assembling a pair of piston rods on both sides thereof and a piston therebetween.
[0002]
[Prior art]
As a general hydraulic damper, there is one shown in FIG.
In the hydraulic damper 2 shown in FIG. 1, a piston 6 that reciprocates in the axial direction is accommodated in a hydraulic cylinder 4, and hydraulic chambers 8 a and 8 b are formed on both sides of the piston 6 in the axial direction. Both hydraulic chambers 8a and 8b are filled with hydraulic oil. The piston rod 10 is of a double rod type provided to project from both axial ends of the piston 6.
[0003]
One end of a hydraulic cylinder 4 is connected to one end of a connecting member 12, and the other end of the connecting member 12 is connected to one of the structures of the building via a ball joint 14. On the other hand, one end of the piston rod 10 opposite to the connecting member 12 with respect to the piston 6 is connected to the other of the building structure via a ball joint 14.
[0004]
In the structure of the building, when an external force such as an earthquake is applied to the hydraulic damper 2 in the axial direction, relative movement occurs between the hydraulic cylinder 4 and the piston 6, and the piston 6 The damping force from the hydraulic oil moving between the hydraulic chambers 8a and 8b through the valve 16 is applied to the end face of the hydraulic damper 2 in the direction opposite to the moving direction. Can perform vibration control.
[0005]
As a conventional structure of the piston 6 and the piston rod 10 in the hydraulic damper 2 of the double rod type, there is a structure in which the piston 6 and the piston rod 10 are integrally formed as shown in FIG. . However, when the damping valve 16 as shown in the figure is provided inside the integrally formed piston 6, it is actually difficult to machine the piston 6, and the piston 6 and the piston rod 10 can be separated. It must be structured.
[0006]
Therefore, as shown in FIG. 7, there is a structure in which a screw structure is provided at a central portion in the length direction of the piston rod 10, and both end surfaces of the piston 6 are fastened and fixed with nuts 17. However, in such a structure, the nut 17 closes the entrance and exit of the valve 16 provided inside the piston 6 after assembly. This causes a problem that the valve 16 inside the piston 6 cannot be adjusted or replaced later.
[0007]
Therefore, as shown in FIG. 8, the piston rod is divided into two piston rods 10a and 10b, and a male screw 18 and a female screw 20 are provided at the respective ends on the coupling side so that the step 22 of the piston rod 10a is A structure is adopted in which the shoulder 24 on the end face of the piston rod 10b clamps the two steps inside the piston 6 so as to be clamped.
[0008]
In such a structure, even when the maximum damping force is applied to the piston 6 during the vibration damping operation of the hydraulic damper 2, the piston 6 sandwiched between the piston rods 10a and 10b is not loosened. Therefore, it is desirable to apply a tightening torque equal to or more than a certain value between the piston rods 10a and 10b to generate a load equal to or greater than the maximum damping force in the axial direction and pinch the piston 6.
[0009]
[Problems to be solved by the invention]
However, in such a structure, when screw-connecting the piston rods 10a and 10b on both sides, in addition to the tightening torque required to pinch the piston 6 by generating a load greater than the maximum damping force in the axial direction, the piston rod 10 Since a tightening torque for frictional force or the like generated between the step 22 of the piston 10a, the shoulder 24 of the piston rod 10b, and the contact surface of the piston 6 is also required, it is necessary to further increase the tightening torque. However, the increment varies depending on the coefficient of friction between them. Therefore, it was very difficult to control the load for pinching the piston 6 by the tightening torque.
[0010]
Accordingly, the present invention has been made in view of the above-described problems, and in a double rod type hydraulic damper, when assembling a piston and a pair of piston rods, the piston is surely pinched so as not to be loosened. It is an object of the present invention to provide a hydraulic damper that can be used.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, a hydraulic damper according to the present invention is a hydraulic damper having a piston that is held between two piston rods. The piston is held by removing a gap between the other piston rod and the piston, which is generated when the piston rod is added, with the tensile load being applied.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
FIGS. 1 to 4 are diagrams referred to for describing an embodiment of a hydraulic damper according to the present invention.
[0013]
In the description of the hydraulic damper according to the embodiment of the present invention shown in FIGS. 1 to 4, the same parts as those of the conventional hydraulic damper are denoted by the same reference numerals and described. The description of the same configuration and operation as in the first embodiment will be omitted.
[0014]
FIG. 1 shows a state before the piston rods 10a and 10b and the piston 6 are assembled. A male screw portion 18 is formed at one end of the piston rod 10a, and a female screw portion 26 (tensile jig) capable of withstanding a maximum damping force, which will be described later, is formed around a shaft hole radially inside the male screw portion 18. Mounting part) is provided. At one end of the piston rod 10b, there is provided a female screw portion 20 which is screw-coupled to the male screw portion 18, and the piston rod 10b has a hollow tubular shape.
[0015]
The piston 6 is provided with a through hole 21 penetrating along the axis thereof, and a hole having a diameter larger than the diameter of the through hole 21 is provided outside both ends of the through hole 21.
FIG. 2 shows a state where the piston rods 10a and 10b and the piston 6 are assembled.
[0016]
The assembling work according to the present embodiment is based on the following steps.
First, as shown in FIG. 3, the piston rods 10a and 10b and the piston 6 are temporarily assembled. Thereafter, a reaction bolt 30 (tensile jig) having male screw portions 28a and 28b formed at both ends is inserted into the piston rod 10b, and one of the male screw portions 28a is inserted into the female portion at the tip of the piston rod 10a. The screw 26 is screwed. Then, the female screw portion 33 of the reaction force plate 32 (tensile jig) in which the female screw portion 33 is formed to face the other male screw portion 28 b of the reaction force bolt 30 is screwed.
[0017]
Next, as shown in FIG. 4, a jack 34 is arranged between the portion of the piston 6 having no hole for the valve 16 and the reaction force plate 32, and the jack 34 causes the reaction force plate 32 to be moved from the piston rod 10 b to the reaction force plate 32. By applying a load to the separating side (the left side in the figure), the female screw portion 26 inside the distal end portion of the piston rod 10a is pulled through the male screw portion 28a of the reaction force bolt 30, so that the piston rod 10a A tensile load equal to or greater than the maximum damping force is applied to the male screw portion 18. As a result, a load equal to or greater than the maximum damping force is generated between the step portion 22 and the contact surface of the piston 6 with which the step portion 22 of the piston rod 10a contacts. By the way, the maximum damping force means the maximum load acting during the vibration control operation of the hydraulic vibration damper 2.
[0018]
Conversely, between the shoulder 24 and the contact surface of the piston 6 with which the shoulder 24 of the piston rod 10b comes into contact, the equivalent load is reduced or the shoulder 22 of the piston rod 10a and the male screw 18 A gap is generated due to the extension of the portion between the two. As a result, the female screw portion 20 of the piston rod 10b can be further tightened to the male screw portion 18 of the piston rod 10a, whereby the shoulder 24 of the piston rod 10b comes into contact with the contact surface of the piston 6 with the shoulder. The portions 24 come into contact without any gap.
[0019]
After the female thread 20 of the piston rod 10b is tightened to the male thread 18 of the piston rod 10a and the shoulder 24 comes into contact with the contact surface of the piston 6, the jack 34 is removed to release the load by the reaction force bolt 30. The tensile load generated between the piston rod 10a and the reaction force bolt 30 is generated between the shoulder 22 of the piston rod 10a and the shoulder 24 of the piston rod 10b, and the piston 6 is moved between the piston rods 10a and 10b. Is caught by a load greater than the maximum damping force.
[0020]
After the above operation is completed, the reaction bolt 30 and the reaction plate 32 are removed to complete the assembly of the piston 6 and the piston rods 10a and 10b. As a result, the gap between each of the shoulder 22 of the piston rod 10a and the shoulder 24 of the piston rod 10b and the contact surface of the piston 6 is equal to or more than the maximum damping force of the hydraulic damper 2 in the axial direction of the piston 6. Since the load is applied, the tightening of the male screw portion 18 and the female screw portion 20 is not loosened and the fixing of the piston 6 is not loosened during the vibration control operation of the hydraulic vibration damper 2.
[0021]
【The invention's effect】
As described above, according to the hydraulic damper of the present invention, the piston is sandwiched between the pair of piston rods with a load equal to or greater than the predetermined value. The fixation of the pinched piston can be prevented from being loosened.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a state before assembling a piston 6 and piston rods 10a and 10b according to an embodiment of a hydraulic damper according to the present invention.
FIG. 2 is a sectional view showing a state in which a piston 6 and piston rods 10a and 10b in FIG. 1 are assembled.
FIG. 3 is a sectional view showing an assembling process of the piston 6 and the piston rods 10a and 10b in FIG.
FIG. 4 is a cross-sectional view showing another assembly process of the piston 6 and the piston rods 10a and 10b in FIG.
FIG. 5 is a sectional view of a conventional general hydraulic damper 2;
FIG. 6 is a side view showing the structure of a conventional piston 6 and piston rod 10.
FIG. 7 is a sectional view showing the structure of another conventional piston 6 and piston rod 10.
FIG. 8 is a sectional view showing the structure of another conventional piston 6 and piston rods 10a and 10b.
[Explanation of symbols]
2 Hydraulic vibration damper 4 Hydraulic cylinder 6 Piston 8a, 8b Hydraulic chamber 10, 10a, 10b Piston rod 12 Connecting member 14 Ball joint 16 Damping valve 17 Nut 18 Male thread 20 Female thread 21 Through hole 22 Step 24 Shoulder Part 26 female screw part 28a male screw part 28b male screw part 30 reaction force bolt 32 reaction force plate 33 female screw part 34 jack

Claims (4)

In a hydraulic damper having a piston that is held between two piston rods, a gap between the other piston rod and the piston, which is generated when a tensile load of a predetermined value or more is applied to one piston rod, A hydraulic damper, wherein the piston is held by removing the piston with the tensile load applied. The hydraulic damper according to claim 1, wherein a tension jig mounting portion is provided at a tip end of the one piston rod. 3. The hydraulic vibration damper according to claim 2, wherein a tip end of said one piston rod and a tension jig are connected by a screw connection. The hydraulic damper according to claim 3, wherein the screw connection has a strength that can withstand a maximum damping force during the vibration control operation.

Images