JPH01188477A - Oilless sliding member - Google Patents

Abstract

PURPOSE:To eliminate the need for oiling and to improve slidability and durability by coating fluoroplastic via a primer contg. a silane coupling agent on a ceramics material having ruggedness, then polishing the coating so that the exposed part of the ceramics material and the fluoroplastic coexist on the surface. CONSTITUTION:The fluoroplastic 3 is coated via the primer 2 contg. the silane coupling agent on the ceramics material 1 having the ruggedness on the surface down to the part shown by an alternate long and short dash line. This surface is polished to form the surface where the exposed part of the ceramics material 1 and the part coated with the fluoroplastic 3 coexist. Such surface is used as a sliding surface. The fluoroplastic 3 contributes to a decrease of the coefft. of friction on the surface, thus capable of enhancing the slidability.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an oil-free sliding member used for a pressurized sliding surface of an oil-free bearing or an oil-free sliding table.

[Prior Art] FIG. 3 shows the main structure of a mold clamping machine for a molding machine, which is equipped with a plurality of bearings. In the same figure, the upper half is during the mold clamping operation.
The lower half shows the state during mold opening operation 6 When the handle 10 for increasing or decreasing the mold clamping stroke S is operated in the forward or reverse direction, the piston 16 in the mold clamping cylinder 15 moves forward or backward. The back and forth movement of the piston 16 is transmitted to the movable plate 17 via the first to fourth bearings 11 to 14.
Mold clamping and mold opening operations are performed by the back and forth movement of 7. During mold clamping, a large pressure of about 500 Kg/cm on average is applied to the rotating sliding surfaces of the first to fourth bearings 11 to 14.Furthermore, after mold clamping is completed, the lock nut 18 is operated to prevent the piston 16 from retreating,
As before, large pressure is applied to the first to fourth bearings 11 to 14 due to mold clamping. When the mold is opened, the first to fourth bearings 11 are
~14 needs to be reversed.

In this way, a mold clamping machine for a molding machine has a large number of bearings 11 to 1.
4 is provided, and a large pressure is applied to its rotating and sliding surface. Further, a linear sliding surface exists between the mold clamping cylinder 15 and the piston 16 as well.

[Problem to be solved by the invention] It is necessary to constantly supply lubricating oil to these rotating sliding surfaces and linear sliding surfaces, and for this reason, it is necessary to constantly operate a pump for oil supply. . If the supply of lubricating oil is stopped, the sliding surface may seize and become unusable.

Furthermore, there is a problem in that waste oil oozes from the sliding surface and pollutes the environment, making it practically difficult to use it in a clean room. Furthermore, regular maintenance is essential for replenishing lubricating oil and disposing of waste oil, and maintenance and inspection require a great deal of time, effort, and cost.

Therefore, in order to improve the lubricity of the sliding surfaces, a fluororesin coating was applied.I:! It is conceivable to reduce the number of scratches and eliminate the need for lubricating oil supply. However, since fluororesin has low hardness, there is a problem in that when it is used for a pressurized sliding surface, it wears out in a short time. In addition, since fluororesin has good mold release properties, it easily peels off from the base material of the sliding surface, and there is a problem that it is not suitable for practical use as a side bottom, especially in the case of pressurized sliding surfaces.

The present invention has been made in view of these points, and its object is to provide an oil-free sliding member that does not require oiling on the pressurized sliding surface.

[Means for Solving the Problems] In order to solve the above-mentioned problems, in the oil-free sliding member according to the present invention, as shown in FIG. A fluororesin 3 is coated via a primer 2 containing a silane coupling agent, and the surface is polished so that exposed parts of the ceramic material 1 and parts covered with the fluororesin 3 coexist on the surface. That is.

In Fig. 1, the part indicated by the broken line is the ceramic material 1.
This is the convex part. Before the surface is polished, the fluororesin 3 is coated up to the area indicated by the dashed line. By polishing this surface, the protrusions of the ceramic material 1 and the fluororesin 3 are removed.
is scraped off to form a surface in which a portion where the ceramic material 1 is exposed and a portion covered with the fluororesin 3 coexist, and this is used as a sliding surface.

[Function] In the present invention, as described above, the ceramic material 1 is provided on the surface.
Since the polishing was performed so that exposed parts and parts covered with the fluororesin coating 3 coexist, the ceramic material 1 exposed on the surface acts to prevent the progression of wear of the fluororesin 3, and the fluororesin 3 contributes to reducing the coefficient of friction on the surface and increases sliding properties.

The edges of the fluororesin 3 isolated in the recess of the ceramic material 1 are exposed, so it is easily exposed to the risk of peeling.
In the present invention, since the fluororesin 3 is coated via the primer 2 containing a silane coupling agent, a bonding strength so strong that it exceeds the breaking strength of the fluororesin 3 is obtained, and the fluororesin 3 is There is no risk of peeling. Therefore, it is suitable for practical use on pressurized sliding surfaces.

[Example code] Examples of the present invention will be described below.

FIG. 2 is a manufacturing process diagram of the oil-free sliding member of the present invention.

Here, an example will be described in which a ceramic sprayed layer is formed on the surface of a base metal to form a ceramic material having irregularities on the surface, and a fluororesin coating is applied thereon. The base metal is made of, for example, steel, stainless steel, copper or copper alloy, aluminum or aluminum alloy. The shape of the base metal is not particularly limited, and it may be a roll material for oil-free bearings or a slab material for oil-free sliding beds.The surface of this base metal may be sand-plated or shot-plated. , or electric discharge machining method, laser processing method,
The surface is roughened by engraving, or the surface is processed to have a specific pattern.

A nickel-chromium powder containing, for example, 80% by weight of nickel and 20% by weight of chromium is plasma sprayed onto this surface-roughened or surface-treated base metal to form an undercoat layer. Thereafter, ceramic fine particles are plasma sprayed to form a top coat layer. Examples of ceramic fine particles include gray alumina, white alumina,
Titania, alumina titania, spinel, mullite,
Powders such as zirconia ittria, zirconia magnesia, zirconia mullite, zirconia calcia, zirconia silica, and cobalt blue can be used. Here, 96% alumina and 2% titania are used.
．． A gray alumina powder containing 3% by weight was used.

When the base metal is iron, the bonding strength of the gray alumina sprayed layer can be increased by providing a nickel-chromium sprayed layer as an undercoat layer. In other words, when gray alumina is sprayed directly onto a steel material, the bonding strength between the gray alumina sprayed layer and the steel material is only 1 to 2 kg/m even if the surface of the steel material is plasted in advance.
Although it only shows n+2, if a nickel-chromium layer is provided as an undercoat layer, the yield will be 3 to 5 kg/kg under the condition that the surface of the iron material is plasted in advance.
A bonding strength of gl@2 is obtained. Note that nickel/aluminum or nickel/chromium/aluminum can also be used as the undercoat layer.

Next, a fluororesin coating is applied, but prior to this, a primer is applied. For example, when PFA resin is used as the fluororesin, an aqueous solution of a mixture of furfuryl alcohol and fluororesin powder is used, but even when applied to the ceramic surface, it does not show good adhesion. We investigated a method to increase adhesive strength by using it in combination with a ring agent.

Coupling agents include titanium-based, silane-based, aluminum-based, and boron-based ones, but the ones that are particularly effective are silane-based ones, which have amino groups in their molecules. For reference, the silane coupling agents used in the experiment are listed below. Vinyl coupling agents include vinyltrimethoxysilane, vinyltriethoxysilane, and vinyltris(2-methoxyethoxy)silane; amino coupling agents include N-(2-aminoethyl)3-aminopropylmethyl Dimethoxysilane, N-(2-aminoethyl)3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3
-glycidoxypropylmethyldimethoxysilane, 2-
(3,4-epoxycyclohexyl)ethyltrimethoxysilane, other coupling agents include 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-mercaptopropyl Examples include trimethoxysilane.

The primer is applied, for example, by an air spray method. After applying, leave it for about 15 minutes, then heat it at 250"C for 3
Bake for 0 minutes. After that, fluororesin is powder coated.

Various fluororesin powders are commercially available, including TFE resin (tetrafluoroethylene resin), PFA
Resin (fluorinated alkoxyethylene resin), EPE resin (
Although fluorinated ethylene propylene ether resin), FEP resin (tetrafluorinated ethylene hexafluorinated propylene copolymer resin), etc. can be used, PFA resin MP-10 manufactured by DuPont Mitsui Fluorochemical Co., Ltd. was used here.

Powder coating is applied to the target thickness using an electrostatic gun, but it is also possible to heat the coating in advance and apply it using the fluidized dipping method.Once the coating is completed, it is heated from room temperature in a furnace. The material is heated to a surface temperature of 360 to 400° C. and fired. When the firing temperature is around 430°C, the adhesion strength decreases. After raising the temperature, a holding time of about 20 minutes is required.The zero surface temperature is monitored at the end surface of the material from before to after firing. The heating time in the furnace is approximately 60 minutes, but the surface temperature heating time varies depending on the size of the material. After firing, it is taken out of the furnace, allowed to cool naturally, and the surface is polished.

The present inventor has prepared a solution containing the above-mentioned silane coupling agent in a solvent, or powdered PFA with approximately 20% water by weight.
A primer is prepared by adding 1 to 5 times a silane coupling agent to a mixture of approximately 58% by weight furfuryl alcohol, approximately 20% by weight ammonia, approximately 0.3% by weight surfactant, and ceramic. The bonding strength between the film and the fluororesin film was investigated. The adhesive strength was quantitatively determined by a beer test in a 90° direction.

As a result, it was discovered that an amino-based coupling agent is particularly superior and can firmly adhere a fluororesin to a ceramic film.

The present invention was made based on this discovery, and was only made possible by the establishment of a bonding technique that can reliably prevent the separation of fluororesin isolated in the recesses of the ceramic material.

Note that the application of the oil-free sliding member of the present invention is not limited to oil-free bearings, but can be widely applied to rotating sliding surfaces and linear sliding surfaces.For example, it can be applied to various types of work. The machine is
The workpiece holding stand and the tool holding stand are each slidable, and the oil-free sliding member of the present invention can also be used on these sliding surfaces.

FIG. 4 is a diagram showing a schematic configuration of a roll surface polishing machine.

The roll 21 is supported by a roll bearing 29 on a bearing stand 22 so that the axis of rotation is in the horizontal direction. A mirror polishing member 23 is in contact with the outer peripheral surface of the roll 21 .

This mirror polishing member 23 is supported by an arm 25 and is rotatable in a horizontal plane. A motor 24 for rotationally driving the mirror polishing member 23 is arranged at the rear of the arm 25, and the arm 25 has a power transmission mechanism for transmitting the rotational driving force of the motor 24 to the mirror polishing member 23. It is preparation. The arm 25 is vertically adjustable with respect to the movable base 26. When mirror polishing a large diameter roll 21, the arm 25 is moved upward, and when mirror polishing a small diameter roll 20, the arm 25 is moved upward. 25 downward. Regardless of the diameter of the roll 21, the mirror polishing member 23 is positioned substantially directly above the rotation axis of the roll 21, and the mirror polishing member 23 is pressed against the roll 21 from the upper surface of the roll 21. The roll 21 is driven to rotate during the polishing operation, and the mirror polishing member 23 pressed against the upper surface of the rotating roll 21 wipes the upper surface of the roll 21 while being driven to rotate itself. , which is driven reciprocally in the horizontal direction. For this purpose, the movable table 26 that supports the arm 25 is movable back and forth along a sliding surface 28 provided on the fixed table 27, and is driven back and forth in the horizontal direction during polishing work. be. The oil-free sliding member of the present invention can be used for this sliding surface 28. Also, roll 2
The oil-free sliding member of the present invention can also be used on the sliding surface of the roll bearing 29 that supports the 0 or 21 rotating shaft.

[Effects of the Invention] In the oil-free sliding member according to the present invention, since the polished surface contains a ceramic material and a fluororesin coating,
The ceramic material prevents the progression of wear, and the fluororesin coating improves sliding properties.If used on pressurized sliding surfaces, lubrication is not required, and environmental pollution due to waste oil can be prevented. This has the effect of eliminating the need for maintenance for lubrication and making handling easier. Furthermore, since the fluororesin is coated on the ceramic material via a primer containing a silane coupling agent, there is no fear that isolated fluororesin coatings in the recesses of the ceramic material will peel off, and the ceramic material has excellent durability.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of the oil-free sliding member of the present invention, Fig. 2 is a diagram showing the manufacturing process of the same, and Fig. 3 is a diagram showing the outline of a mold clamping machine for a molding machine using the oil-free sliding member of the present invention. FIG. 4 is a side view of a roll mirror polishing machine using the oil-free sliding member of the present invention. 1 is a ceramic material, 2 is a primer, and 3 is a fluororesin.

Claims (1)

[Claims] (1) A ceramic material with an uneven surface is coated with a fluororesin using a primer containing a silane coupling agent, so that parts where the ceramic material is exposed and parts covered with the fluororesin coexist on the surface. An oil-free sliding member characterized by being made by polishing.