JP4039663B2 - Damping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a damping device that absorbs vibration energy such as an earthquake, and more specifically, kinetic energy generated in association with relative displacement between two objects such as a building structure in the event of an earthquake, impact, etc. is expressed as thermal energy. The present invention relates to an apparatus for converting to attenuating.
[0002]
[Prior art]
As an apparatus for attenuating energy at the time of an earthquake, it is converted into thermal energy of a viscous body and attenuated with an amplifying function of a relative displacement portion, for example, Japanese Patent Laid-Open Nos. 10-184757 and 10-184786. Attenuating devices disclosed in the publication are known.
[0003]
Since these devices convert most of the kinetic energy into the thermal energy of the viscous body, the viscous body absorbs energy, generates heat, and expands. In the cylinder that seals the viscous body with the expansion, the internal pressure rises and damages the sealing member used for sealing.
[0004]
[Problems to be solved by the invention]
As means for solving this problem, one disclosed in JP 2000-274474 A is known. However, the viscous body itself does not release all the heat to the outside, and accordingly, the viscosity of the viscous body decreases, and as a result, the attenuation capability of the attenuation device decreases. In addition, the temperature of the viscous body changes depending on the external environment temperature such as the outside air temperature and radiant heat from the sun, and the same result is obtained.
[0005]
For the above damping device, a solution has been proposed for the expansion of a viscous body that has absorbed kinetic energy. However, the viscosity decreases due to the temperature rise of the viscous body caused by heat generation, etc., and the damping capacity of the device decreases accordingly. The problem of variation in damping capacity due to the above has not been solved. As means for reducing the temperature rise of such a viscous body, there are means such as increasing the capacity of the viscous body and reducing the load per unit volume or cooling the viscous body to dissipate heat. There are issues such as making it large and complex. The attenuation device according to the present invention has been proposed in order to solve such problems.
[0006]
[Means for Solving the Problems]
The gist of the damping device according to the present invention for solving the above-mentioned problems is that linear motion means that linearly moves, rotational motion conversion means that converts linear motion of the linear motion means into rotational motion, and rotational motion conversion means. In the damping device comprising a viscous damping means that attenuates the kinetic energy by the viscous resistance of the rotating viscous body and a device main body that supports each of the means, the sliding surface of the screw portion in the rotational motion converting means is arranged on the sliding surface of the damping device. A solid lubricant having a self-lubricating function is about 15% or more of the sliding surface and about 25% so that a part of the total damping force can be borne by the rotational motion converting means and shows a stable lubricity. It is that it is buried uniformly in less than.
[0007]
The viscous damping means and the rotational motion converting means are configured separately so that the heat generated by the rotational motion converting means does not adversely affect the viscous damping means, and are connected via a connecting portion. Including things.
[0008]
According to the damping device of the present invention, the absolute amount of kinetic energy absorbed by the viscous material can be reduced, and the reduced amount can be replaced by another damping means. Thereby, the temperature rise of a viscous body is reduced and the fall of the viscosity of this viscous body comes to be prevented.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the attenuation device 1 according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the damping device 1 includes a screwed input shaft 3 that is a linear motion means that linearly moves relative to the apparatus body 2 by an external force from the outside, and a linear motion of the linear motion means. A rotary converter 4 that is a rotary motion converter that converts rotational motion by an even number, and an inner tube (rotary body) that is a viscous damping means that is rotated by the rotary motion converter and attenuates kinetic energy by the viscous resistance of the viscous body 5. 6) and an apparatus main body 2 composed of a fixed outer cylinder 2a and a support body 2b for supporting the above-described means.
[0010]
The screw portion 3a provided on the outer peripheral portion of the input shaft 3 is formed as a three-thread trapezoidal screw or a three-thread screw having equal left and right crest angles. The threaded portion 4a carved on the inner wall of the rotation converter 4 that is screwed to this is also formed in the same manner.
[0011]
When relative displacement occurs between the input shaft 3 and the apparatus main body 2 due to seismic energy from the outside, the rotation conversion body 4 is rotated around the axis of the input shaft 3 that does not rotate by the screw portions 3a and 4a. The inner tube 6 that is rotated in the same direction by the rotation conversion body 4 via the connecting portion 4b is separated from the rotation conversion body 4 as shown in FIG. The heat generated in the rotation converter 4 is provided so as not to adversely affect the heat, and is injected and sealed between the inner tube 6 and the fixed outer tube 2a which is a part of the apparatus body 2. Viscous resistance due to the viscous body 5 is received. As a result, a force for stopping the rotational movement of the inner tube 6 is generated, and the resistance force is transmitted to the sliding contact surfaces of the screw portions 3a and 4a via the rotation converter 4, and the frictional force is applied to the sliding contact surfaces. Is generated and amplified, and becomes the main damping force of the entire apparatus.
[0012]
Next, the damping force of the damping device 1 will be described by setting a relational expression.
Attenuation force in all axial directions of the damping top (the total of the damping part, the total of the damping part of the input shaft 3, the rotation converter 4, the inner tube 6, the other thrust bearing part 7, etc.): P
Axial damping force of viscous body 5: Qn
Axial damping force of screw part: Qs
Axial damping force of thrust bearing 7: Qb
Then, P = Qn + Qs + Qb (1)
It is expressed.
[0013]
The axial damping force Qn of the viscous body 5 is
Damping force of viscous body 5: Qd
Viscous part speed amplification ratio: S
Then,
Qn = Qd × S (2)
The viscous part speed amplification ratio S is:
Inner tube 6 outer diameter: D
Thread lead: L
Pi ratio: π
Then, S = D · π / L.
[0014]
The axial damping force Qs of the threaded portion is
Effective diameter of screw: Ds, Friction coefficient of screw: μ1,
Thread part speed increasing sub-ratio: S1 (= Ds · π / L)
Then, Qs = P · μ1 · S1 (3)
It becomes.
[0015]
The axial damping force Qb of the thrust bearing portion 7 is
Friction coefficient of thrust bearing 7: μ2
Thrust bearing speed increase sub-ratio: S2 (= Db · π / L)
Then, Qb = P · μ 2 · S 2 (4)
However, the speed increasing sub-ratio S2 of the thrust bearing portion 7 is S2 = Db · π / L as the rotational diameter Db of the thrust bearing 7.
[0016]
Here, when the formulas (2), (3), and (4) are substituted into the formula (1) and arranged into a function of Qn,
P = Qn / (1−μ1 · S1−μ2 · S2) Equation (5) is obtained.
As shown in the equation (5), the axial damping force P of the damping top is obtained by increasing the product of the friction coefficient of the screw and the speed amplification ratio when the damping force of the viscous body 5 is constant, or a thrust bearing. A large axial damping force P can be obtained by increasing the product of the friction coefficient of the portion 7 and the speed amplification ratio.
[0017]
Further, if the same screw and thrust bearing are used and the total axial damping force P is made equal, the damping force of the viscous body 5 can be reduced.
[0018]
【Example】
A comparative example of the damping device 1 according to the present invention and a conventional known damping device is shown.
The known damping device is a device using a ball screw,
Total axial damping force P: 50,000 kg · f
Friction coefficient of ball screw: 0.005
Speed increase sub-ratio of screw part: 4.0
Friction coefficient of thrust bearing: 0.005
Thrust bearing speed increase sub-ratio: 10.1
And
[0019]
When the axial damping force Qn is obtained by the above equation (5),
Qn = 46,475 kg · f, and the viscous material bears about 90% or more of the total axial damping force P.
[0020]
On the other hand, in the damping device 1 of the present invention, since the ball screw is not used and replaced with a sliding screw, the load on the viscous body 5 is the same as described above, with the friction coefficient of the sliding screw being 0.104. When Qn is calculated with the total axial damping force P = 50,000 kg · f,
Qn = 26,650 kg · f. This is about half of the total axial damping force P. As a result, in the viscous body 5, the damping force is about half that of a known damping device, and the burden is reduced. Therefore, the viscous body 5 expands due to heat, and the increase in pressure and temperature due to the expansion are reduced in the damping device 1 of the present invention.
[0021]
In the damping device 1, the resistance force transmitted to the sliding contact surface of the screw portion between the input shaft 3 that is the rotational motion conversion means and the rotation converter 4 generates the screw portion axial damping force by the screw portion friction. Let The size is proportional to the friction and the size of the screw portion speed amplification ratio, and the screw portion speed amplification ratio is inversely proportional to the size of the screw lead. Therefore, in order for the sliding screw to function effectively as the rotational motion converting means, it is necessary to select an appropriate screw portion speed amplification ratio. Further, the damping force generated in the threaded portion is converted into heat energy at the sliding contact surface, and the temperature of the metal input shaft 3 and the rotation converter 4 is increased and thermally expanded. As a result, the difference in the thermal expansion coefficient between the input shaft 3 and the rotation converter 4 reduces the backlash of the screw and, in extreme cases, causes seizure or the like. It is necessary to limit this. Therefore, the axial damping force of screw friction is practically set in the range of about 25% to 60% of the total axial damping force P based on the specifications of the damping device 1.
[0022]
Considering the requirements of the screw parts 3a and 4a of the damping device 1, the denominator cannot be 0 or less from the above equation (5).
1> (μ1 · S1 + μ2 · S2) Equation (6)
Therefore, the friction coefficient μ1 of the screw portion: 0.104, the screw speed increasing sub-ratio S1: 4.0, the friction coefficient μ2 of the thrust bearing portion 7: 0.005, the thrust bearing speed increasing sub-ratio S2: 10.1. Then, 1> 0.416 + 0.0505 = 0.471, which satisfies the above formula (6). Here, when considering the ratio of viscous damping force,
0.65 to 0.48> (μ 1 · S 1 + μ 2 · S 2) Equation (7) is satisfied. In this embodiment, since it is 0.471, Equation (7) is also satisfied.
[0023]
Therefore, as can be seen from the above formulas (6) and (7), even if the friction coefficient and the speed amplification ratio are arbitrary, it is sufficient if the above conditions are satisfied, and a degree of freedom can be given in the design of the device. . In the damping device 1 of the present invention, the rotation converter 4 is easily rotated, and the speed amplification ratio S1 of the thread portion is set in the range of 2.1 to 5.1 from the appropriate range of the frictional damping force.
[0024]
About the friction coefficient μ2 of the thrust bearing portion 7 and the thrust bearing portion speed increasing sub-ratio S2, when a sliding thrust bearing is applied here, the friction coefficient between iron and copper alloy, which is a general material, is approximately If it is 0.15, it exceeds 1 only by the product of μ 2 · S 2, and rotation is impossible. Therefore, the thrust bearing portion 7 needs to be a bearing having a very small friction coefficient.
[0025]
In addition, the threaded portion is attached at an arbitrary angle from horizontal to vertical depending on the installation environment of the attenuation device, and slight bending or the like occurs due to a gap in the attachment, its own weight, or a minute gap in the device. However, as a screw condition that operates smoothly, a triple thread is used. This triple-threaded screw improves the ability to prevent bending of the shaft due to shaft damping force by combining the stability of straight shaft travel by simultaneous contact support of the three thread surfaces with a cross section perpendicular to the shaft and the centripetal force of trapezoidal screws. Yes.
[0026]
Further, the use of the three-thread screw increases the contact area as compared with the single-thread screw, can reduce the effective length of the screw, facilitates processing, and improves accuracy. As trapezoidal screws, in addition to 30-degree trapezoidal screws and 29-degree trapezoidal screws, special trapezoidal screws having a thread angle of 60 degrees, metric screws, and thread shapes having an angle equal to the thread can be used. Similar actions and effects can be obtained.
[0027]
An appropriate amount of gap must be provided in the axial direction of the screw portions 3a and 4a. The thread surface of the thread portion receives friction due to the axial damping force, is converted into heat energy, and generates heat. The material of the screw parts 3a, 4a and the rotation converter 4 is made of alloy steel and high-strength brass. Due to the difference in thermal expansion coefficient between them, the pitch gap between the male screw and the female screw is about the pitch direction of the screw. As it becomes narrower, proper backlash must be maintained.
[0028]
In such a case, to avoid thermal expansion, it can be resolved by increasing the amount of backlash, but in that case, the impact during operation becomes large, so that the backlash is prevented to prevent damage to the damping device. Less rush is better. Therefore, as shown in FIG. 2, an effective diameter tolerance method is adopted. For example, for a screw having a diameter of 60 mm and P14, a tolerance is applied so that the axial backlash is 0.11 to 0.16 mm. When the axial backlash is calculated by a known JIS standard tolerance method, it becomes 0.048 to 0.362 mm, and the tolerance width becomes very wide and is not applicable to special uses such as a lead screw. .
[0029]
A member having a self-lubricating function is employed for the screw portions 3a and 4a. Since the attenuation device 1 is sometimes used as a member of a building beam incorporated in a wall, it is required that maintenance is not required for a long period of time. Therefore, the rotation converter 4 in which the solid lubricant 8 is embedded in the screw portion 4a is employed. As shown in FIGS. 3 to 4, the solid lubricant 8 is uniformly disposed at about 15% or more and less than about 25% of the sliding surface of the screw. Thereby, the stable lubricity is shown.
[0030]
【The invention's effect】
As described above, the damping device according to the present invention includes linear motion means that linearly moves, rotational motion conversion means that converts linear motion of the linear motion means into rotational motion, and viscosity that is rotated by the rotational motion conversion means. In a damping device comprising a viscous damping means for damping kinetic energy by the viscous resistance of the body and a device main body that supports each of the means, an overall damping force in the damping device is applied to the sliding surface of the screw portion in the rotational motion converting means. The solid lubricant having a self-lubricating function is uniform at about 15% or more and less than about 25% of the sliding surface so that a part of the sliding motion can be borne by the rotational motion conversion means and exhibits stable lubricity. because it is embedded in, by the friction with a screw portion is effectively utilized in damping force, thereby reducing the burden of the viscous damping means by viscous body, decrease of the damping capability of the viscous damping means Preventing, in which excellent effects referred to stabilize the damping performance of the entire damping device.
[0031]
Further, the rotational motion converting means is a screw part of a screw pair and has a self-lubricating function by embedding a solid lubricant in the screw part of the sliding screw, so that long-term maintenance is not required and stable lubricity is obtained. In addition, the quality of the attenuation device is improved. The viscosity damping means and the rotational motion converting means are connected separately via a connecting portion so that the viscous damping means is not adversely affected by heat generated by the rotational motion converting means. The temperature rise of the body is reduced and the viscosity is prevented from decreasing.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a schematic configuration of an attenuation device 1 according to the present invention.
FIGS. 2A and 2B are explanatory views (A) and (B) for comparing crossing for backlash of a thread portion in the damping device 1 according to the present invention.
FIG. 3 is a cross-sectional view (A) and a plan view (B) showing a state in which a solid lubricant is disposed in a threaded portion of the damping device 1 according to the present invention.
FIG. 4 is a cross-sectional view (A) and a plan view (B) showing a state in which a solid lubricant 8 is disposed on a thread portion 4a in the damping device 1 according to the present invention.
[Explanation of symbols]
1 damping device, 2 device body,
3 Threaded input shaft, 3a Threaded part,
4 Rotation converter, 4a Screw part,
4b connecting part,
5 viscous body, 6 inner tube (rotating body),
7 Thrust bearing, 8 Solid lubricant.

Claims (2)

Linear motion means that linearly moves, rotational motion conversion means that converts linear motion of the linear motion means into rotational motion, and viscosity damping means that is rotated by the rotational motion conversion means and attenuates kinetic energy due to the viscous resistance of the viscous material; In the damping device comprising the device main body that supports each of the above means,
A self-lubricating function is provided so that a part of the total damping force in the damping device can be borne by the rotational motion converting means on the sliding surface of the screw portion in the rotational motion converting means and stable lubrication is exhibited. Having a solid lubricant uniformly embedded in about 15% or more and less than about 25% of the sliding surface;
Attenuator characterized by. The viscous damping means and the rotational motion converting means are configured separately so that the heat generated by the rotational motion converting means does not adversely affect the viscous damping means, and are connected via a connecting portion. thing,
The attenuation device according to claim 1.

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