JP2000320611A - Sliding base isolator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superior durability by constituting a sliding support arranged between a lower skeleton and an upper skeleton in such a manner as arranging a plane sliding plate and a sliding material with their respective sliding contact faces contacted with each other, using a PTFE resin composite material for the sliding material, and applying lubricant to the sliding contact face of the sliding material. SOLUTION: In constituting this sliding base isolator reducing the earthquake external force by a building structure, a civil engineering structure, etc., a sliding support 3 is arranged between a lower skeleton 1 and an upper skeleton 2. The sliding support 3 comprises a plane sliding plate 4 and a sliding material 5 whose respective sliding contact faces are mutually contacted with each other and a member 6 and a middle plate 7 elastically deformed till the maximum static friction force of the sliding material 5 are arranged therein as necessary. Circular recesses 9a-9c are formed in the sliding contact face 8 with overlapped parts 10 formed therein mutually. At least, lubricant composed of fluorine grease is applied to the sliding contact face 8 and the lubricant is held in the recesses 9a-9c.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding seismic isolation device, and more particularly to a building structure from a high-rise structure such as a building or a tower to a low-rise structure such as a detached house, and a civil structure from a bridge such as a road or a railway. A sliding seismic isolation device that supports and reduces external force.

[0002]

BACKGROUND OF THE INVENTION Seismic isolation is the reduction of the seismic force on a building in some way. The "base insulation type", which reduces the input of earthquakes into a building by inserting some device between the foundation and the building, is the mainstream of seismic isolation devices or seismic isolation methods. For example, there is a slip seismic isolation device using a combination of a slide bearing and a horizontal spring. In this method, a sliding material such as a resin sliding plate is attached to a basic footing of a sliding bearing, and the plate and a metal plate attached to a column are allowed to slide. In other words, the building slides against horizontal vibrations of the ground due to the earthquake, so that a force greater than the frictional force acting on the slip surface acts on the building.The horizontal spring moves to prevent the building from moving significantly. Is regulated. Therefore, the smaller the friction coefficient of the slip material is, the greater the seismic isolation effect is, and a stable and small friction coefficient is required to surely exhibit the seismic isolation effect.

Therefore, a fluorine-based material such as ethylene tetrafluoride (hereinafter abbreviated as PTFE) resin having a small coefficient of friction is often used as the sliding material. Further, in order to obtain a large seismic isolation effect with a smaller coefficient of friction, it is known to employ a coating made of a fluorine-based or polysiloxane-based compound having a reactive group on a sliding surface of a smooth plate as a mating material. (Japanese Patent No. 2629011). Also,
A slip bearing is known in which a concave portion is provided on the surface of a sliding material, a gel lubricant is sealed in the concave portion, and the lubricant is applied around the concave portion (Japanese Utility Model Publication No. 6-40243).

[0004]

However, there is a problem that the coating formed of a fluorine-based or polysiloxane-based compound having a reactive group formed on the sliding surface of the smooth plate has insufficient durability.

In addition, when a gel lubricant is filled and applied to the concave portion provided on the surface of the sliding material, the lubricant itself deteriorates with time even if the initial friction coefficient can be reduced. Depending on the shape of the concave portion, the lubricant itself is discharged from the lubricating surface, and there is still a problem that the durability is not sufficient.

Further, the seismic isolation effect of a slip seismic isolation device having a slide bearing composed of a PTFE resin sliding material and a metal plate is not stable in an early stage of an earthquake due to a large initial friction coefficient. .

On the other hand, the slip bearing has a problem that the slip characteristic is largely dependent on surface pressure, which changes with the surface pressure.
Generally, a slip-isolation device is used in combination with a laminated rubber. However, when the laminated rubber undergoes large shear deformation, the surface pressure applied to the slip material increases, so that the friction coefficient greatly fluctuates. As a result, there is a problem that the seismic isolation performance of the slip seismic isolation device cannot be maintained.

The present invention has been made to address such a problem, and has a stable seismic isolation effect at the initial stage of an earthquake, has excellent durability, and has a low friction coefficient stably for a long period of time. The purpose of the present invention is to provide a sliding seismic isolation device with extremely low surface pressure dependence.

[0009]

The slip seismic isolator according to the present invention includes a slip bearing provided between a lower frame and an upper frame, and the slip bearing is provided so that the smooth plate and the slip member are mutually movable. The sliding members are arranged in contact with each other, the sliding member is made of a PTFE-based resin composite material, a lubricant made of fluorine grease is applied to at least the sliding contact surface of the sliding member, and A plurality of concave portions having no open ends on the outer peripheral edge are formed on the sliding contact surface so as to communicate with each other.

[0010] The fluorine grease as a lubricant applied to the sliding contact surface has an initial characteristic regardless of whether it undergoes oxidative deterioration due to oxygen in the air, hydrolysis action due to moisture, or heat generation action due to large shear deformation. Can be stably maintained for a long period of time. As a result, it is possible to obtain a sliding seismic isolation device having excellent durability and having extremely low surface pressure dependency.

A plurality of recesses having no open ends are formed in the outer peripheral edge of the sliding contact surface so as to communicate with each other, so that the lubricant applied to the sliding contact surface is discharged from the sliding surface. The lubrication characteristics do not differ even if slippage occurs in all directions.

A study of the cause of the large friction coefficient in the early stage of the earthquake occurrence revealed that the PTFE resin was not easily oriented in the sliding direction at the very early stage of the start of sliding. The PTFE resin shows a small coefficient of friction because it is easily oriented in the sliding direction and the PT
This is because a part of the FE resin is transferred to form a film and slips between the PTFE resins, and the like. Therefore, the friction coefficient at the very early stage of the start of sliding can be reduced, and the characteristics thereof can be reduced. It turned out that we should be able to maintain it. The present invention
It is the result of studying how to reduce the initial coefficient of friction and maintain its properties over time.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A slip seismic isolator according to the present invention will be described with reference to FIG. FIG. 1 is a cross-sectional view of a slip bearing portion of the slip seismic isolation device. A sliding bearing 3 is provided between the lower frame 1 and the upper frame 2. The sliding bearing 3 is composed of a smooth plate 4 and a sliding member 5 whose sliding surfaces are in contact with each other. Reference numeral 6 denotes a member that elastically deforms up to the maximum static frictional force of a sliding material such as laminated rubber, and 7 denotes an intermediate plate, which are provided as necessary. Also,
9 is a concave portion formed on the sliding surface of the sliding member 5.

The smooth plate 4 constituting the slide bearing 3 can be used as long as it has no protrusions on its surface and is flat and hard. For example, a metal plate, a ceramic plate, a hard resin plate such as a polyimide resin, and a PT hardened by blending a filler.
Any flat plate made of a FE-based resin can be used. Among these, a metal plate is preferable, and a stainless steel plate is most preferable, particularly in consideration of rust prevention, production cost, workability, and the like.

This smooth plate has a surface roughness represented by the maximum height (Ry) on the sliding contact surface of 0.05 to 0.50 μm. Preferably it is 0.10 to 0.20 µm. Here, the maximum height (Ry) refers to a value defined in JIS B0601. By setting the maximum height (Ry) within the above range, an appropriate amount of the lubricant can be held between the sliding surfaces of the smooth plate and the sliding material. Therefore, an appropriate amount of the lubricant can be held over the entire sliding contact surface, and the initial slip property is improved. If the maximum height (Ry) is less than 0.05 μm, the production cost increases and maintenance becomes difficult, and the maximum height (Ry) is less than 0.5 μm.
If it exceeds 50 μm, the wear characteristics of the sliding material will be impaired.

The sliding material 5 constituting the sliding bearing is PTF
It is formed of an E-based resin composite material. The shape may be any shape as long as it can slide on the sliding surface of the smooth plate 4. In particular, the lubricant can be stably held on the sliding contact surface by forming a plurality of concave portions communicating with each other in a shape having no open end on the outer peripheral edge of the sliding contact surface of the sliding member 5. . As the shape having no open end, a circular concave portion in the sliding contact surface is preferable. FIG. 2 shows an example of the shape of the concave portion formed on the sliding surface of the sliding member 5. FIG. 2 is a plan view of the sliding contact surface of the sliding material. Circular recesses 9a, 9b, 9 are formed on the sliding surface 8 of the sliding member 5.
c are formed so as to have mutually overlapping portions 10. By forming the circular concave portion 9 having the overlapping portion 10, even if a slip occurs in any direction due to an earthquake,
The lubricant is not easily discharged from the slip surface without causing any difference in lubrication characteristics and even when the number of slips is large.
Therefore, a sufficient amount of lubricant can be continuously supplied to the slip surface. Forming the plurality of recesses 9 with the overlapping portions 10 allows the lubricant to move between the recesses 9,
This is because almost the entire sliding surface can be covered.

The total projected area of the recesses 9a, 9b and 9c is 5 to 40% with respect to the total surface area of the sliding surface of the sliding member. By setting the content in this range, sufficient lubricity can be ensured, and the surface pressure resistance can be ensured even when the surface pressure applied to the slip material when the laminated rubber undergoes large shear deformation increases. . Further, the surface area of the sliding surface of the sliding member 5 is preferably smaller than that of the sliding surface of the smooth plate 4. By reducing the size, the lubricant is less likely to be discharged from the concave portion 9 having no open end on the outer peripheral edge.

The PTFE-based resin composite material comprises a PTFE-based resin and at least one compounding agent selected from a fibrous compounding agent, a resin powder, and an inorganic compound powder. PT
Examples of the FE-based resin include a PTFE resin and a modified PTFE resin. The PTFE resin is a homopolymer of ethylene tetrafluoride, which is softened at 310 to 390 ° C. and can be subjected to compression molding and extrusion molding, but cannot be subjected to ordinary injection molding. Examples of commercially available products include Algoflon (manufactured by Ausimont), Teflon (manufactured by DuPont), Fluon (manufactured by ICI), and Polyflon (manufactured by Daikin Industries, Ltd.).

In the modified PTFE resin, an ethylene tetrafluoride unit and fluorine of ethylene tetrafluoride are converted to another organic group (-X).
And a substituted tetrafluoroethylene unit. The general formula is shown in Chemical formula 1. The organic group (-X) is not particularly limited, but is preferably a perfluoroalkyl ether group or a fluoroalkyl group.

Embedded image Commercially available modified PTFE resins include Teflon TG70
J (manufactured by Du Pont-Mitsui Fluorochemicals), Polyflon M111 (manufactured by Daikin Industries, Ltd.), Hostaflon TFM1
600 (manufactured by Hoechst) and the like.

The method of polymerizing the above PTFE resin and modified PTFE resin is not limited, but the molecular weight of the resin is about 50.
It is preferably from 10 to 10 million, and more preferably from 1 to 7 million. By having a molecular weight in this range, the friction coefficient can be reduced as a sliding material, and mechanical strength such as creep resistance can be maintained.
In particular, when the modified PTFE shown in Chemical Formula 1 is used, the creep resistance is improved and the allowable surface pressure on the slip surface can be allowed up to about 30 MPa. Along with that, the slip surface can be reduced,
This is preferable because the size of the sliding seismic isolation device can be reduced.

Among the compounding agents that can be added to the PTFE resin, the fibrous compounding agent includes glass fiber, carbon fiber, and whiskers. The carbon fibers may be either pitch-based or bread-based carbon fibers. Commercially available products include Crecamild M101S (manufactured by Kureha Chemical Industry Co., Ltd.) and Donacarbon S241 (manufactured by Osaka Gas Chemicals) as pitch-based carbon fibers, and Vesfight HT as bread-based carbon fibers.
A-CMF0160-0H (manufactured by Toho Rayon Co., Ltd.) and the like.

Other examples of the fibrous compounding agent include various whiskers of short fibers. As a commercial product, Franklin Fiber A is used as calcium sulfate whisker.
-30 (anhydrous salt type), Franklin Fiber H-30
(Hemihydrate salt type) (fiber length 50-60 μm, manufactured by Dainichi Seika Kogyo Co., Ltd.), Tismo N as potassium titanate whisker (fiber length 10-20 μm, manufactured by Otsuka Chemical Co., Ltd.), Thaibreck (fiber length 20 μm, Kawairon Mining) And zinc oxide whiskers such as Panatetra (fiber length: 2 to 50 μm, manufactured by Matsushita Electric Industrial Co., Ltd.), and magnesium sulfate whiskers: Moss Heidi (fiber length: 10 to 30 μm, manufactured by Ube Industries).

Among the compounding agents, the resin powder is preferably a powder that can withstand the molding temperature of PTFE of 380 ° C. For example, thermoplastic polyimide resin (manufactured by Mitsui Chemicals), thermosetting polyimide resin (manufactured by Furon, Ube Industries), polyetheretherketone resin (manufactured by Victrex MC), wholly aromatic polyester resin (Sumitomo Chemical) Industrial Co., Ltd.), aramid powder, polyamide-imide resin (Mitsubishi Kasei), mesocarbon beads (Osaka Gas Chemical Co., Ltd.), Bellpearl (Kanebo Co., Ltd.), Univex (Unitika Co., Ltd.), micro carbon beads (Nippon Carbon Co., Ltd.) Manufactured).

Further, examples of the inorganic compound powder include molybdenum disulfide, zinc oxide, titanium oxide, graphite, metal oxide powder, glass beads, and silica powder.

The amount of the compounding agent is preferably 5 to 40 parts by volume based on 100 parts by volume of the PTFE resin. If the amount of the compounding agent exceeds 40 parts by volume, there may be a problem in moldability or damage to the smooth plate. If the amount is less than 5 parts by volume, the reinforcing effect is poor, and sufficient creep resistance and wear resistance cannot be obtained.

The means for mixing and kneading the various raw materials used in the present invention described above is not particularly limited, and only the powder raw material is dry-mixed with a Henschel mixer, a ball mixer, a ribbon blender, a Redige mixer, an Ultra Henschel mixer, or the like. do it. Further, it is preferable to granulate into a granule having a predetermined particle size that matches the molding method by a wet method or the like. In terms of molding, generally known methods can be employed. Examples include free baking, hot molding, isostatic molding, continuous ram extrusion, paste extrusion, direct molding, and the like. In the step of obtaining the slip material according to the present invention, a predetermined sheet thickness is obtained by skiving after free baking. In order to join the metal plate and the sliding material installed on one footing of the structure, one side of the sliding material is etched to be in a bondable state. After that, they are joined with an epoxy, phenol or polyimide adhesive.

Fluorine grease applied to the surface of the sliding material is particularly preferable as the lubricant of the sliding seismic isolation device of the present invention because of its excellent durability and excellent surface pressure dependency. Fluorine grease is obtained by kneading a low molecular weight PTFE resin powder, for example, a fine PTFE resin powder, as a thickener, in a fluorine oil as a base oil. The reason for using the low molecular weight PTFE resin is to maintain excellent lubricating properties over a long period of time, like the sliding material, and to maintain the lubricating properties without deterioration of the fluorine grease itself with time. .

As the fluorinated oil, a completely fluorinated oil containing a perfluoroalkyl group or a perfluoroether group is preferable because of its excellent heat resistance and oxidation deterioration resistance.
PTFE used as a thickener has a molecular weight of about 50.
Fine powder of about 10,000 to 2,000,000 is preferable. The reason for this is that the polymer becomes fibrillated during kneading and the specific surface area increases. Such PTFE can increase the impregnation amount of the fluorine-based oil, and the fibrillation makes it difficult to discharge from the slip surface. Commercially available products include Fombling lease (manufactured by Ausimont).

The coating amount of the lubricant is, 0.005 to 0.1 g / cm ² against the sliding contact surface of the smoothing plate, preferably 0.01 to 0.05 g / cm ²
It is. When the amount of the lubricant applied is 0.005 to 0.1 g / cm ² , the coefficient of friction is small and sufficient slip properties are obtained. Coating amount
If it is less than 0.005 g / cm ² , the initial friction coefficient cannot be reduced, and if it exceeds 0.1 g / cm ² , the lubricant becomes excessive and the friction coefficient does not improve.

[0030]

EXAMPLE An oxidative deterioration test was performed to evaluate the weather resistance of fluorine grease. The test conditions were as follows: an electric furnace maintained at 230 ° C. (air oven manufactured by Tabai Espec, ST-12)
The test grease was injected for 75 hours into 0), and the change in weight before and after that was investigated. Table 1 shows the results. Test lubricants are shown below. Lubricant A: Fluorine grease; Fombling grease (Ausimont) Lubricant B: PAO (poly-α-olefin) grease (Nippon Steel Chemical) Lubricant C: Silicone grease (Shin-Etsu Chemical) Lubrication Agent D: Ester-based grease (manufactured by Nippon Steel Chemical Co., Ltd.)

[0031]

[Table 1]

From the results shown in Table 1, it was found that the weight loss of the fluorine grease in the oxidation deterioration test was smaller than that of other greases, and that the slidability did not decrease due to the oxidation deterioration even after long-term use.

Examples 1 to 7 and Comparative Examples 1 to 3 A smooth plate and a sliding material for forming a sliding bearing were prepared and subjected to a friction and wear test. A slip material was produced by the following method. 1) Modified PTFE resin (Teflon TG70J (manufactured by DuPont-Mitsui Fluorochemicals)) and glass fiber (MF-M)
B06MB120 (manufactured by Asahi Fiberglass Co., Ltd.)) was weighed so that the resin: fiber = 100: 15 by volume ratio. 2) This was dry-blended using a Henschel dry mixer. 3) Then, using a press machine, φ124mm × φ64mm × 100
mm2 cylindrical preforms were preformed. 4) The cylindrical shaped material was fired at 370 ° C for 4 hours by a free baking method. 5) After that, 100mm x 1000mm x
A 1 mm sheet specimen was obtained. 6) One side of the sheet was adhered by etching with an alkali treatment. 7) One side of a stainless steel jig (20 mm x 20 mm x 15 mm) was joined with an epoxy adhesive to obtain a slip material test piece for friction coefficient μ measurement. 8) Then, at the center of the sliding contact surface, a slip material test piece in which a concave portion having the shape (shape a) shown in FIG. 2 was additionally processed, and an outer diameter φ12 mm
A slide material test piece (shape b) prepared by additionally processing one circular concave part having an inner diameter of φ10 mm and a depth of 1 mm was prepared.

The smooth plate is a stainless steel plate (SUS304)
Is polished so that the surface roughness represented by the maximum height (Ry) is
0.10 ~ 0.40μm specimen (small roughness) and surface roughness of 1.0
1.11.1 μm test piece (large roughness) was prepared.

The lubricant A and the lubricant C were used as lubricants by using the slip material and the smooth plate produced by the above method.
Was applied to the sliding surface of the smooth plate at 0 to 10 g / cm ² to perform a friction and wear test. The test used a reciprocating test machine. The test conditions were as follows: slip speed 23.6cm / sec, surface pressure 15-60MPa,
The reciprocating operation was performed for 300 cycles with a stroke of ± 35 mm, and the dynamic friction coefficient at 10, 100, and 300 cycles was measured. The results are shown in Tables 2 and 3.

[0036]

[Table 2]

[Table 3]

As shown in Tables 2 and 3, the burrs according to the present invention had a small and stable kinetic friction coefficient of 0.03 or less up to 100 cycles, and were excellent in durability. In the initial 10 cycles of the test, the coefficient of kinetic friction was almost stable even if the surface pressure fluctuated.

[0038]

According to the present invention, a lubricant made of fluorine grease is applied to a sliding surface of a sliding member made of a tetrafluoroethylene-based resin composite material, and an outer peripheral edge of the sliding surface is provided. Since a plurality of recesses having no open ends communicate with each other and are formed on the sliding contact surface, deterioration of the lubricant can be suppressed, initial characteristics can be stably maintained for a long time, and surface pressure dependency is maintained. Can be extremely reduced. In particular, since the projected area of the concave portion is 5 to 40% of the surface area of the sliding surface of the sliding material, the friction coefficient can be further reduced.

Further, in the above-mentioned sliding seismic isolator, the sliding material is a tetrafluoroethylene-based resin composite material according to claim 3, and the fluorine-based oil contains a perfluoroalkyl group and a perfluoroether group. By using a fluorine-containing oil, and by setting the surface roughness of the sliding surface of the smooth plate to a maximum height (Ry) of 0.05 to 0.50 μm, the amount of the lubricant applied to the sliding surface of the smooth plate can be reduced. 0.005-0.1g / c
By setting it to m ² , the initial characteristics of the slip-isolation device can be stably maintained for a longer period, and the dependency on the surface pressure can be further reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a slip bearing portion of a slip seismic isolation device.

FIG. 2 is a plan view of a sliding surface of a sliding member.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower frame 2 Upper frame 3 Slip bearing 4 Smooth plate 5 Slip material 6 Laminated rubber 7 Middle plate 8 Sliding surface of slip material 9 Depression 10 Overlap

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) E04B 1/36 E04B 1/36 J E04H 9/02 331 E04H 9/02 331E // C10N 30:00 40: 02 50:10 (72) Inventor Satoru Fukuzawa 970, Ota-Ana, Toin-cho, Inaba-gun, Mie Prefecture F-term in NTN Precision Plastics Co., Ltd.

Claims (7)

[Claims] 1. A slip seismic isolator comprising a slide bearing disposed between a lower frame and an upper frame, wherein the slip bearing is configured such that a smooth plate and a slip member are mutually connected. The sliding member is made of a tetrafluoroethylene-based resin composite material, and a lubricant made of fluorine grease is applied to at least the sliding surface of the sliding member, and the sliding member is A sliding seismic isolation device characterized in that a plurality of concave portions having no open ends are formed in the sliding contact surface on the outer peripheral edge of the surface so as to communicate with each other. 2. The sliding seismic isolation device according to claim 1, wherein a projected area of the concave portion is 5 to 40% with respect to a surface area of the sliding surface of the sliding material. 3. The ethylene tetrafluoride-based resin composite material,
The slip seismic isolation device according to claim 1, wherein at least one compounding agent selected from a fibrous compounding agent, a resin powder, and an inorganic compound powder is mixed with the ethylene tetrafluoride-based resin. 4. The sliding seismic isolation device according to claim 1, wherein the fluorine grease is obtained by blending a fluorine-based oil with a tetrafluoroethylene-based resin powder. 5. The slip-isolation device according to claim 4, wherein the fluorine-based oil is a fluorine-containing oil containing a perfluoroalkyl group or a perfluoroether group. 6. The sliding seismic isolation device according to claim 1, wherein the surface roughness of the sliding surface of the smooth plate is a maximum height (Ry) of 0.05 to 0.50 μm. 7. The slip-isolation device according to claim 1, wherein the amount of the lubricant applied is 0.005 to 0.1 g / cm ² with respect to the sliding surface of the smooth plate.