JPH0995543A - Sliding sheet material, its production thereof, and sliding support device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the frictional resistance on starting in a sliding sheet material used for a bridge constructed by the sliding technique and other general sliding parts. SOLUTION: This sliding sheet material 1 comprises a fluororesin, ultrahigh- molecular-weight polyethylene or aromatic polyester resin sheet, of which the direction (a) of molecular orientation on the surface is in a certain direction. The fluororesin preferably comprises a tetrafluoroethylene resin, which may contain various fillers. The sheet material 1 is effective when stuck to the sliding support surface of, e.g. a sliding bearing in a bridge constructed by the sliding support technique in such a manner that the direction of molecular orientation thereof coincides with the longitudinal direction of the bridge girder.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sliding sheet material used for a bridge of a sliding construction method and other general sliding parts, a manufacturing method thereof, and a bridge sliding support device.

[0002]

2. Description of the Related Art In a bridge, if the length of each bridge girder is long, for example, 300 m or more, the contraction due to drying after placing concrete is large, so that it is necessary to absorb horizontal force. Therefore, a sliding construction method may be adopted in which a fluororesin sliding sheet material is adhered to the sliding support and the bridge girder is placed on and supported by the sliding support. Such a sliding method is preferable even when the bridge girder expands and contracts due to the temperature difference depending on the day and night and the season.

[0003]

However, when the concrete starts to dry, the material that should slide between the bridge girder and the sliding support may not work because of a large initial resistance. For this reason, although the problem is solved with the lubricant, it becomes difficult to select and handle the lubricant because it becomes a severe environment for use outdoors, and it takes time to perform maintenance. Not only bridges but also various structures and workpieces have sliding structures that use sliding sheet materials. Even in these sliding structures, the sliding sheet materials have a satisfactory starting resistance reduction effect. Can be difficult to obtain. For example, the starting resistance may be too large even if the resistance during the stabilizing action is sufficiently small. In any case, if there is a large difference in sliding resistance between the time of starting and the time of stable operation, the problem becomes how much the value of the friction coefficient should be calculated at the time of design, which makes design difficult.

An object of the present invention is to provide a sliding sheet material capable of reducing frictional resistance, particularly frictional resistance at the time of starting, and a slide supporting device using the same. Another object of the present invention is to provide a manufacturing method capable of efficiently manufacturing the sliding sheet material.

[0005]

The sliding sheet material of the present invention is a sheet of fluororesin, ultra high molecular weight polyethylene resin or aromatic polyester resin,
The molecular orientation of the sheet surface is oriented in a fixed direction. Among fluororesins, perfluoro fluororesins such as polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkylvinylether copolymer (PFA), etc. Has excellent slidability such as friction characteristics because the periphery of the molecular skeleton is entirely fluorine. The sheet is not limited to the resin, and may be a resin sheet having a band structure, in which the molecular directions on the sheet surface are oriented in a fixed direction. The resin having a band structure has, for example, a crystallinity of about 20 to 80.
% Of resin or more, and tetrafluoroethylene resin, which is a kind of fluororesin, can be used. Fluorine-based resins such as tetrafluoroethylene resin have a crystallinity of about 50 to 8
If the value is 0% or more, or exceeds these values,
Many band structure parts are considered preferable. The tetrafluoroethylene resin may be a mixture of various fillers. These sliding sheet materials are attached to a sliding support surface such as a sliding support in a bridge of a sliding support construction method, and are effective when molecules are oriented in the longitudinal direction of the bridge girder.

Fluorine resin, ultra high molecular weight polyethylene resin and aromatic polyester resin are plastics which show low friction at low speed and are widely used as sliding materials. As a sheet of these resins, generally used ones with unoriented molecular orientation are used, and when a load is applied to the mating material to cause it to slide, a large peak resistance value is shown at startup, after which the resistance value decreases. Stabilizes to a substantially constant value. This is because the molecular orientation is aligned in a certain direction by sliding, and the decrease in the resistance value also occurs when a sheet material that has been oriented in advance is used and the sheet material is slid in the orientation direction. Therefore, when the sliding sheet material in which the molecular direction of the present invention is orientated in advance in a certain direction is adhered and the orientation direction is the sliding direction, the peak value of the starting resistance is reduced,
Or it almost disappears and starts sliding smoothly. Therefore,
When this sliding sheet material is used for a sliding support of a bridge or a portion of other structure where the sliding direction is constant, the frictional resistance is stable from the time of start-up and a preferable sliding action is obtained. Therefore, the design is easy and the construction method as designed can be realized. In a sheet of fluororesin, ultra-high molecular weight polyethylene resin, and aromatic polyester resin, when the surface molecular direction is oriented in a certain direction, the coefficient of friction along the orientation direction is higher than that of an unoriented sheet. The smallness was confirmed by experiments and reported in various literatures. Examples of the aromatic polyester resin include polymers made of paraoxybenzoic acid, aromatic dicarboxylic acids, aromatic diols, etc., and homopolymers made of paraoxybenzoic acid and those made of the above three types of copolymers. Etc. These are wholly aromatic polyester resins,
A homopolymer made of paraoxybenzoic acid has excellent heat resistance, and the above three types of copolymers have excellent creep resistance and moldability. A polymer having such a molecular structure has a property that orientation is strongly exhibited. Further, those formed by compression molding, ram extrusion molding, etc. are preferable because they have appropriate flexibility as a sheet material.

The band structure is a structure in which slippage is likely to occur as a structure of a molecular texture, and the friction coefficient is further lowered by orienting the molecular direction in a fixed direction. The band structure is a structure peculiar as a molecular assembly of plastics, and a tetrafluoroethylene resin is typical as a resin having this structure. The wear rate of the tetrafluoroethylene resin is significantly reduced when the filler is mixed, as compared with the case where the filler is not mixed. It is considered that this is because the filler prevents the band structure from being broken. As a filler,
It is preferable to use any one kind or two or more kinds of glass fiber, carbon fiber, graphite powder, and polyimide resin powder. The same applies to the case where the filler is mixed with the ultra high molecular weight polyethylene. The sliding sheet material in which the molecular directions are oriented can be manufactured by, for example, calendar processing. In calendering, a sheet material is stretched in the rolling direction in the process of rolling into a sheet shape, and the molecular arrangement is oriented in the stretching direction along with the stretching. Therefore, the oriented sheet material for sliding can be manufactured without adding an additional orientation process. In addition to this, as a method of manufacturing the sliding sheet material having the above-described configuration, a method of forming a non-oriented sheet shape and then stretching it by ironing to orient the molecular arrangement in the stretching direction can be adopted.

The bridge slide supporting device of the present invention includes a bridge support portion such as a slide support for mounting a bridge girder movably in the longitudinal direction,
The sliding sheet material having the above-mentioned molecular orientation is attached to either or both of the sliding surface on the bridge girder side in contact with the bridge bearing portion. The orientation direction is the longitudinal direction of the bridge girder. In the bridge, the sliding direction is constant, and the use of the sliding sheet material of the present invention eliminates the peak resistance at the time of starting and stabilizes the friction coefficient, so that the bridge girder can be smoothly contracted as designed. Therefore, it is possible to ensure the stability of the friction coefficient and realize maintenance-free without applying grease or lubricating oil.

[0009]

An embodiment of the present invention will be described with reference to the drawings. The sliding sheet material 1 is a fluororesin or ultra-high molecular weight polyethylene sheet, and the sheet surface has a molecular direction a oriented in a certain direction. The orientation in the molecular direction a may be only on the surface of the sheet material 1 or in the entire thickness range. As the fluororesin, tetrafluoroethylene resin (PTFE) is preferable. PTFE
Has a small friction coefficient because its molecular texture has a band structure. The PTFE may be a mixture of fillers. The thickness of the sliding sheet material 1 is an appropriate thickness according to the purpose of use and the place of use, for example, 0.1 mm to 10 mm.
The thickness is preferably about 0.3 mm to 6 mm.
If the thickness of the sheet material is too thin, a problem due to insufficient strength of the sheet during calendar processing or ironing processing may occur, while if the thickness of the sheet material is too thick, a peeling step during the production of the sheet, so-called It is considered that the skiving process becomes difficult. The width and the length of the sliding sheet material 1 may be arbitrary dimensions according to the manufacturing method and the purpose of use. The sliding sheet material 1 may be a wide sheet material cut into an arbitrary shape and size according to the purpose of use.

The sliding sheet material 1 oriented in the molecular direction a can be manufactured, for example, by calendaring shown in FIG. FIG. 6A shows a calendar type in which the roll 2 is arranged in an inverted L shape, and FIG. 6B shows an upright two-type calendar type. The calendar format is not particularly limited. In addition to this, after producing a sheet in an unoriented state, the sheet may be stretched by ironing to orient the molecular arrangement in the stretching direction.

FIG. 2 shows a bridge slide supporting device using the sliding sheet material 1 of FIG. In this bridge, multiple points in the middle of the bridge girder 3 bridged between the abutments 4 and 4 at both ends are supported by the piers 5, and the upper end of each pier 5 and the bridge girder 3 are supported.
A bridge slide support device 6 is provided between the two. The bridge slide supporting device 6 is provided with a plurality of bridge bearings 7 as sliding bearings on the top end surface of the bridge pier 5, and the bridge girders 3 are provided on each bridge bearing 7.
The supported portion 8 provided on the lower surface of the is mounted.
The sliding sheet material 1 of FIG. 1 is adhered to the upper surface of the bridge support portion 7 with an adhesive. The material of the sliding sheet material 1 in this case was PTFE. The orientation direction a of the sliding sheet material 1 is the longitudinal direction of the bridge girder 3. Supported part 8 is bridge girder 3
It is formed in a downward groove shape extending in the longitudinal direction of and covers the bridge support portion 7. The bridge support part 7 and the supported part 8 are
It may be made of steel or other metal.

In the bridge slide supporting device of FIG. 2, when the sliding sheet material 1 is not provided, when the concrete of the bridge girder 3 dries after being placed, it greatly shrinks in the longitudinal direction (the direction of the arrow). At this time, the slip resistance in the same direction as the contraction direction is shown in FIG.
As shown in (A), a large peak resistance P occurs at startup. Each resistance value shown in the figure is an example. On the other hand, when the sliding sheet material 1 molecularly oriented by PTFE as shown in FIG. 2C is provided as described above, FIG.
As described above, the peak resistance is eliminated, and the friction girder is stabilized, so that the bridge girder 3 contracts smoothly as designed. Therefore, it is possible to ensure the stability of the friction coefficient and realize maintenance-free without applying grease or lubricating oil.

FIG. 5 shows another example of the bridge slide supporting device. In this example, the bridge slide support device 11 is applied to the bridge piers 10, 10 that support both ends of a truss type bridge girder 9. In this bridge slide supporting device 11, the sliding sheet material 1 of FIG.
The molecular orientation method of the sliding sheet material 1 is the longitudinal direction of the bridge girder 9. The bridge supporting portion 12 and the supported portion 13 may be made of steel or other metal. In this way, the sliding sheet material 1 is applied to both the bridge supporting portion 12 and the supported portion 13.
Even when the sliding sheet materials 1 are slid on each other by providing the above, the peak resistance at the time of starting due to the orientation disappears, and the friction coefficient becomes stable.

The sliding support device using the sliding sheet material 1 can also be used as a seismic isolation structure in buildings and other buildings. In that case, the sliding sheet material 1 is used in a sliding support portion where the sliding direction is a constant direction.

[0015]

EXAMPLES The parallel degree of molecular orientation in the sliding sheet material 1 of FIG. 1 is suitably 5 to 50%, preferably 5 to 30%. The degree of parallelism in this case refers to the ratio of oriented molecules among the molecules of the entire resin of the sliding sheet material 1. In the case of PTFE, according to the research report (Kogakuin University Research Report No. 49), as shown in FIG.
It has been shown that the coefficient of friction decreases at 71% parallelism and then tends to increase with increasing parallelism.
It is also stated that the coefficient of friction in the stretching direction generally showed a value smaller than that in the perpendicular direction. Also, P
A filler may be added to TFE, ultra high molecular weight polyethylene, or wholly aromatic polyester to reduce wear. As the filler, it is preferable to use one kind or two or more kinds of glass fiber, carbon fiber, graphite powder, and polyimide resin powder. The compounding amount of the filler is preferably 5 to 4
It is 0% by weight, more preferably 10 to 30% by weight. Further, the sliding sheet material 1 may have a wire mesh, and may further have a metal plate such as an iron plate adhered thereto. In the bridge slide supporting devices 6 and 11 of FIGS. 2 and 5,
The adhesive for adhering the sliding sheet material 1 is good, for example, because a two-component epoxy resin or the like composed of a base material such as araldite and a curing agent can be firmly adhered.

[0016]

The sliding sheet material of the present invention is a sheet of fluororesin, ultra high molecular weight polyethylene or aromatic polyester resin, or a sheet of resin having a band structure, in which the molecular direction on the surface of the sheet is fixed. Since it is oriented in such a manner, the peak resistance at the time of starting is eliminated or becomes small, and the friction coefficient is stabilized. Therefore, it is used in various sliding locations where the sliding direction is constant, and smooth sliding is obtained from the initial stage. When the resin is a tetrafluoroethylene resin, the friction coefficient becomes smaller. Further, when the filler is mixed with the tetrafluoroethylene resin, wear is reduced and the life is extended. In the case of the method for producing a sliding sheet material by calendering of the present invention, the molecules can be oriented without adding a stretching process,
It is possible to produce a sliding sheet material that is molecularly oriented with good productivity. Further, in the case of the method for producing a sliding sheet material by ironing, it is easy to adjust the degree of molecular orientation by stretching by the degree of ironing. Since the bridge slide supporting device of the present invention uses the above-mentioned sliding sheet material so that its orientation direction is along the longitudinal direction of the bridge girder whose sliding direction is, there is no peak resistance at the time of start-up, and the friction coefficient is It is stable, so the bridge girder contracts smoothly as designed. Therefore, it is possible to reduce the number of times grease and lubricant oil are supplied and the amount of supply, and it is possible to ensure a stable friction coefficient and realize maintenance-free even without applying these lubricant oils for a long period of time.

[Brief description of drawings]

FIG. 1 is a perspective view of a sliding sheet material according to an embodiment of the present invention.

2A is a side view of a bridge using the sliding sheet material, FIG. 2B is a perspective view of the pier, and FIG. 2C is a perspective view of the pier slide supporting device.

3 (A) and 3 (B) are explanatory diagrams showing starting resistance recording in the case where the sliding sheet material is not oriented and where it is oriented.

FIG. 4 is a graph showing the relationship between the degree of parallelism of orientation and the stretching ratio of a tetrafluoroethylene resin and the coefficient of sliding friction.

FIG. 5A is a side view of a bridge to which a pier slide supporting device according to another embodiment is applied, and FIG. 5B is a cutaway side view showing a part of a portion B thereof in an enlarged manner.

FIG. 6 is an explanatory view showing each example of a calendar type which is a method for manufacturing a sliding sheet material.

[Explanation of symbols] 1 ... sliding sheet material, 3 ... bridge girder, 4 ... abutment, 5 ... pier,
6 ... Bridge pier slide support device, 7 ... Bridge support part, 8 ... Supported part, 9 ... Bridge girder, 10 ... Pier, 11 ... Bridge pier slide support device,
12 ... Bridge bearing, 13 ... Bearing, a ... Direction of orientation

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Claims (8)

[Claims] 1. A sliding sheet material, which is a sheet of a fluororesin, an ultrahigh molecular weight polyethylene resin, or an aromatic polyester resin, in which the molecular direction of the sheet surface is oriented in a fixed direction. 2. A sliding sheet material, which is a resin sheet having a band structure, in which the molecular direction of the sheet surface is oriented in a fixed direction. 3. The sliding sheet material according to claim 2, wherein the resin is a tetrafluoroethylene resin. 4. The filler as described above, wherein any one of glass fiber, carbon fiber, graphite powder, and polyimide resin powder, or two or more thereof are mixed.
Alternatively, the sliding sheet material according to claim 3. 5. The method according to claim 1, 2 or 3.
The sliding sheet material as described above, which is affixed to a sliding support surface of a bridge of a sliding support method and in which the orientation direction of molecules is the longitudinal direction of the bridge girder. 6. Claim 1 or claim 2 or claim 3.
The method for producing a sliding sheet material according to the above, wherein the sheet material is stretched in a rolling direction by calendering into a sheet shape and the molecular arrangement is oriented in the stretching direction. 7. Claim 1 or claim 2 or claim 3.
The method for producing a sliding sheet material according to the above, wherein the sheet material for sliding is formed into a sheet and then stretched by ironing to orient the molecular arrangement in the stretching direction. 8. The method according to claim 1 or claim 2 or claim 1 or both of a bridge bearing portion on which a bridge girder is movably mounted in the longitudinal direction and a sliding surface on the bridge girder side in contact with the bridge bearing portion. A bridge slide supporting device in which the sliding sheet material according to 3 is attached and the molecules of the sliding sheet material are oriented in the longitudinal direction of the bridge girder.