JP2005265152A - Sliding structure and manufacturing method therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the sliding structure and the production method capable of improving the abrasion resistance of the sliding faces that contact each other. <P>SOLUTION: The sliding structure 1 is equipped with at least two sliding members 3, 5 with the sliding face that contacts each other. The two opposed sliding faces are formed on the thickness of coating layer 7, 9 (its average thickness is desirably in the range of 5 to 50μm) including the magnetic material 11, 13 (desirably ferrite or rare earth) that consists of a matrix 12, 14 dispersively. An opposed faces 15, 17 of those coating layers are the same magnetic polar (desirably N pole) each other. A mutual contact pressure is reduced with the repulsive power through the means that the surface is the same polar, which can improve the resistance friction performance. The matrix includes desirably more abrasion resistant reinforcement (hard particle and/or hard fiber). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding structure including at least two sliding members that slide relative to each other and a method for manufacturing the same. In particular, the present invention relates to a sliding structure capable of improving the wear resistance of sliding surfaces in contact with each other in the at least two sliding members, and a manufacturing method thereof.

  A sliding member, for example, a CVT (Continuously Variable Transmission; continuously variable transmission; continuously variable transmission; hereinafter referred to as CVT) of a vehicle such as a piston and cylinder of a vehicle engine unit, a belt and pulley system, or the like. A plurality of metal rings which are components of the belt are required to have high wear resistance in order to withstand high-speed operation and severe sliding conditions of high temperature and pressure. For this reason, various types have been conventionally developed in which a coating containing a solid lubricant such as polytetrafluoroethylene (PTFE), graphite, or molybdenum disulfide in the binder is formed on the surface thereof.

Japanese Patent Laid-Open No. 11-303992 Japanese Patent Laid-Open No. 11-31501

  However, the sliding member is required to have a performance capable of withstanding even more severe conditions as the output of a vehicle engine part or CVT increases. Alternatively, the sliding member tends to be thinner than the conventional product in accordance with demands for weight reduction and size reduction. Therefore, the sliding member is desired to be further improved in wear resistance.

  Therefore, the present invention has been developed to solve such a problem, and in a sliding structure including at least two sliding members, it has a feature that can improve the wear resistance of sliding surfaces that are in contact with each other. It aims at providing a sliding structure and its manufacturing method.

According to the present invention, a sliding structure including at least two sliding members having sliding surfaces in contact with each other is provided. That is, in the sliding structure of the present invention, a coating layer made of a matrix containing a magnetic material dispersed on each of the two opposing sliding surfaces is formed. And the surface where these coating layers face is mutually the same magnetic pole, It is characterized by the above-mentioned.
In the sliding structure having such a configuration, the surfaces of the sliding surfaces have the same magnetic pole, so that they repel each other and the contact pressure between the sliding surfaces can be reduced. For this reason, the frictional force by sliding can be reduced and the wear resistance can be improved. Moreover, in the coating layer disclosed here, since the magnetic material is dispersed in the matrix, the strength of the magnetic material is improved and the wear resistance is excellent.
In particular, in a sliding structure having such a configuration, when a liquid lubricant such as oil is fed between sliding surfaces facing each other, the space between the sliding surfaces is lubricated by the liquid lubricant. Therefore, the direct solid contact area between the sliding surfaces can be reduced by the repulsive force between the sliding surfaces and the presence of the lubricant. Moreover, the contact area (namely, fluid lubrication area) through a liquid lubricant can be increased. For this reason, the frictional force is extremely reduced, and particularly high wear resistance can be realized.
Patent Documents 1 and 2 both disclose that the sliding surface of the sliding member contains a magnetic material, but both have different purposes, and a friction reducing effect on the sliding surface is obtained. Not. Also, sliding members such as magnetic bearings are known that use magnets themselves, but magnetic bearings do not directly contact each other. Since the magnet itself has low wear resistance and is inferior in impact load resistance, the effect of the present invention cannot be achieved.

Preferably, the surfaces of the facing coating layers each have an N pole.
Compared to the S pole, the N pole is less likely to cause metal wear powder to adhere to the surface of the sliding member from the direction of the magnetic field lines. For this reason, it is possible to reduce the contamination on the surface of the sliding member and to prevent friction due to the wear powder during sliding.

  As the magnetic material, any magnetic material can be used, but preferably contains ferrite and / or rare earth. These magnetic materials have stable magnetic properties. Moreover, the thing containing a ferrite etc. is economical.

  In a preferred form, the magnetic material contained in the matrix may be particulate. Here, “particulate” means a small lump that can be dispersed in the matrix and does not limit the shape. A round spherical shape is a typical example, but is not limited thereto, and may be, for example, an irregular crushed piece shape. Preferably, the average particle diameter of the particulate magnetic material contained in the matrix is in the range of 0.5 to 5 μm. When the magnetic material has a size within a predetermined range, the magnetic material can be uniformly dispersed and have stable magnetism, that is, repulsive force and strength.

Moreover, it is preferable that the average thickness of the said coating layer is the range of 5-50 micrometers.
When the thickness of the coating layer is within such a range, a coating layer that is stable in strength while maintaining wear resistance can be obtained. Moreover, it is excellent also in economical efficiency.

  In a particularly preferred form, the matrix further comprises a wear-resistant reinforcement. By including the wear resistance reinforcing material, the wear resistance of the coating layer can be further improved.

  Examples of the reinforcing material include nonmagnetic hard particles and / or nonmagnetic hard fibers. These can be easily dispersed in the matrix and are excellent in the effect of improving the wear resistance. Moreover, since it is nonmagnetic, it does not affect the magnetism of the coating layer.

For example, the hard particles or fibers preferably comprise non-oxide ceramics or oxide ceramics such as SiO ₂ and / or Al ₂ O ₃ . Alternatively, it is preferable to include a particulate and / or fibrous carbon material such as carbon fiber. In particular, these ceramic materials and carbon materials are excellent in wear resistance improvement effect and heat resistance. In addition, oxide ceramics such as SiO ₂ and Al ₂ O ₃ and carbon materials are economical, and the wear resistance of the coating layer can be improved at low cost.

As a preferred embodiment of the sliding structure of the present invention, one of the sliding members may be a piston of a vehicle engine portion, and the other may be a cylinder.
The contact portion (sliding surface) between the piston and the cylinder is required to have particularly high wear resistance in order to withstand high-speed operation and high-temperature and high-pressure severe sliding conditions. By forming the coating layer of this configuration on the sliding surface, the contact pressure with each other can be reduced and the wear resistance can be improved.

  In this application, it is preferable that the coating layer is formed at least near the top and bottom dead center of the skirt portion outer peripheral surface of the piston and the inner peripheral surface of the cylinder. In the sliding movement of the piston in the cylinder, particularly strong frictional force is applied to the piston at the outer peripheral surface of the skirt portion and the cylinder at the top and bottom dead center of the inner peripheral surface, and wear resistance is required. Therefore, the wear resistance can be effectively improved by forming the coating layer disclosed herein at the predetermined portion.

As another preferred aspect of the sliding structure of the present invention, the at least two sliding members are provided on a belt of a vehicle CVT (that is, a continuously variable transmission, typically a belt and pulley system). It can be.
The overlapping contact portions, that is, sliding surfaces, of the plurality of annular sliding members (hoops) stacked to constitute the ring can withstand high-speed operation of the ring and severe sliding conditions of high temperature and high pressure. Especially high wear resistance is required. By forming the coating layer of this configuration on the sliding surface, the contact pressure with each other can be reduced and the wear resistance can be improved.

In this application, the covering layer is preferably formed on the inner peripheral surface and the outer peripheral surface of the plurality of stacked sliding members (hoops) that constitute the ring. In the high-speed rotation of the ring, particularly strong frictional force is applied in this portion, and wear resistance is required. Therefore, the wear resistance can be efficiently improved by forming a coating layer at the predetermined portion. For this reason, the ring can be prevented from being cut or damaged.
Further, the material of the annular sliding member (hoop) constituting the ring is not limited, and any material can be applied, but a metal that can suitably improve the wear resistance is preferable.

  As another aspect, the present invention provides a method of manufacturing a sliding structure with improved wear resistance. That is, the sliding structure manufacturing method of the present invention is a method of manufacturing a sliding structure including at least two sliding members having sliding surfaces that are in contact with each other, and at least two sliding members are prepared. A step of forming a coating layer by applying a matrix containing dispersed magnetic materials to sliding surfaces of the sliding members that are in contact with each other, and applying a magnetic field to the magnetic materials to make contact with each other And a step of making the surfaces of the respective coating layers of the sliding surface have the same magnetic pole. By this manufacturing method, it is possible to provide a sliding structure according to any one of the above-described aspects.

In a preferred aspect, the means for applying a magnetic field to the magnetic material is performed by arranging the sliding member in a predetermined magnetic field direction in an external magnetic field. By this means, the facing coating layer surface can be easily made to have the same magnetic pole.
Further, in the present manufacturing method, the sliding structure can be manufactured by appropriately selecting the configuration so as to have the configuration of some aspects described above.

  Hereinafter, preferred embodiments of the present invention will be described. It should be noted that matters other than matters specifically mentioned in the present specification (for example, composition of coating layer, composition of magnetic material and matrix, composition of reinforcing material, composition of sliding member, etc.) Matters necessary for this can be grasped as design matters of those skilled in the art based on the prior art in the field. The present invention can be carried out based on the contents disclosed in this specification and common technical knowledge in the field.

  In this specification, the sliding structure means a structure in which a part of the sliding structure can become a sliding part during normal use (or operation). In the sliding structure of the present invention, the surfaces of the sliding surfaces that contact each other in at least two sliding members constituting the sliding structure may be the same magnetic pole, and various configurations may be applied for that purpose. Can do. Specifically, a coating layer is formed on the sliding surface, and the coating layer contains a magnetic material.

  For example, as schematically shown in FIG. 1, in the sliding structure 1 of the present invention, two sliding members 3 and 5 have surfaces facing each other as sliding surfaces, Covering layers 7 and 9 are formed. Magnetic materials 11 and 13 are dispersed in the coating layers 7 and 9, respectively, and the surfaces 15 and 17 of the coating layers are formed so as to exhibit the same magnetic pole. Preferably, the coating layers 7 and 9 are formed by dispersing the magnetic materials 11 and 13 in the form of particles in the matrices 12 and 14 as shown in FIG. In FIG. 1, the magnetic materials 11 and 13 are schematically shown in substantially one row. However, in the actual coating layers 7 and 9, a plurality of the magnetic materials 11 and 13 are overlapped, staggered, or regular. Or irregularly distributed. The magnetic materials 11 and 13 may be any magnetic poles as long as the surfaces facing each other are the same magnetic pole, and preferably the surfaces of the coating layers 7 and 9 are N poles as shown in FIG. Further, although not shown in FIG. 1, the surfaces thereof may be S poles.

  As the magnetic materials 11 and 13, any conventionally known magnetic material can be used without particular limitation. For example, ferrite, rare earth, magnetite, alnico magnet and the like can be suitably used. Of these, ferrite or rare earth is particularly preferable. Ferrite is suitable because of its great features of low cost, excellent chemical resistance, and high coercivity. Examples of ferrite include, but are not limited to, Ba-based or Sr-based. In addition, rare earths have particularly strong and stable magnetic properties. Examples of the rare earth include, but are not limited to, Sm—Co, Nd—Fe—B, and Sm—Fe—N.

The magnetic materials 11 and 13 included in the matrices 12 and 14 may be in any form, for example, may be acicular or other indeterminate shapes, but are preferably in the form of particles whose size approximates to some extent. . The average particle diameter is appropriately selected according to the use and is not particularly limited, but is preferably in the range of about 0.5 to 5 μm, more preferably 0.5 to 3 μm, and particularly preferably about 1 to 2 μm.
The content of the magnetic materials 11 and 13 contained in the matrices 12 and 14 is not particularly limited and is appropriately selected depending on the application, but is preferably 1 to 20% by mass, more preferably 1 to 10% by mass in the matrix. It is contained in the range of%. By being in this range, an appropriate repulsive force is obtained and the mechanical strength by the matrix is improved, and the wear resistance is excellent.

  The material (base material) constituting the matrices 12 and 14 may be an organic material or an inorganic material as long as the magnetic materials 11 and 13 can be dispersed. For example, a conventionally known heat-resistant binder can be used without particular limitation. Specifically, for example, epoxy heat resistant resin, polyimide heat resistant resin, polyamideimide resin, alkyd resin, phenol resin, polyacetal resin, polyether resin, polyether sulfonic acid resin, polybenzimidazole resin, and / or colloidal Silica materials such as silica can be used. Among these, polyamideimide resin and colloidal silica are particularly preferable because they are excellent in heat resistance.

The covering layers 7 and 9 can contain an abrasion resistance reinforcing material. For example, as schematically shown in FIG. 2, the coating layers 7 and 9 include nonmagnetic hard fibers 21 and / or nonmagnetic hard particles 23 as reinforcements in the matrices 12 and 14. It can be distributed and included.
The hard fiber 21 is not particularly limited as long as it is a non-magnetic fiber having wear resistance and heat resistance, and a conventionally known hard fiber can be used. For example, carbon fiber or glass fiber can be used. In addition, since the hard fiber has good dispersibility, it is preferable that the hard fiber is a short fiber.
The hard particles 23 are not particularly limited as long as they are nonmagnetic particles having wear resistance and heat resistance, and conventionally known hard particles can be used. For example, an oxide or non-oxide ceramic powder, for example, a metal oxide such as silica, alumina, titania, zirconia, silicon nitride, and / or tin oxide can be used.

  These wear-resistant reinforcing materials can be used alone or in combination of two or more nonmagnetic hard particles or fibers. Moreover, those content rates are not specifically limited, Although it is suitably selected according to a use, Preferably it contains in 1-20 mass% in a matrix, More preferably, it contains in 1-10 mass%. By being in this range, the strength of the coating layer itself can be further improved while maintaining the wear resistance effect due to the repulsive force of the magnetic material. Moreover, the mixture ratio of a hard particle and a hard fiber is not specifically limited, According to a use, it can select suitably. It is preferable to use hard particles having good strength and dispersibility.

Further, in order to further improve the wear resistance, the matrixes 12 and 14 of the coating layers 7 and 9 may contain a conventionally known nonmagnetic solid lubricant as desired. As such a solid lubricant, molybdenum disulfide, graphite, polytetrafluoroethylene, fluororesin and the like can be used without particular limitation. The content is preferably in the range of 1 to 20% by mass, more preferably 1 to 10% by mass.
The average thickness of the coating layers 7 and 9 is appropriately selected depending on the use, but is preferably 5 to 50 μm, more preferably 5 to 30 μm, particularly preferably in order to satisfy stable wear resistance and economy. Is about 5 to 10 μm.

  The present invention includes any application that includes at least two sliding members, and that each member has a portion (sliding surface) that contacts each other and slides during normal use (or operation). It can also be applied. For example, as a preferred example of the sliding structure provided by the present invention, a combination of a cylinder and a piston of a vehicle engine part (that is, an engine), or a belt of a CVT for a vehicle that is typically a belt and pulley system is configured. Ring (that is, a laminate of a number of metal hoops), but is not limited thereto, and may be used in any other application.

  For example, as shown in FIG. 3, coating layers 34 and 35 can be formed on the sliding surfaces of the inner peripheral surface of the cylinder 30 and the outer peripheral surface of the skirt portion of the piston 32, respectively. The covering layers 34 and 35 are formed so that the surfaces facing each other have the same magnetic pole as described above. According to the cylinder 30 and the piston 32, when the piston 32 slides in the cylinder 30, the mutual friction can be suppressed by the coating layers 34 and 35 with a high effect. As a result, wear between the members 30 and 32 is prevented. Therefore, it is possible to prevent a gap from being formed between the cylinder 30 and the piston 32 or a compression leak from occurring between the cylinder 30 and the piston 32 over a long period of time.

  Further, in the cylinder 30, a coating layer 34 is typically provided in the vicinity of the top dead center and the bottom dead center of the cylinder 30 as shown in FIG. 4 without providing the coating layer 34 on the entire inner peripheral surface. Layers 37 and 38 can also be formed. In particular, by forming the coating layers 37 and 38 only near the top dead center and bottom dead center of a cylinder that is subjected to strong frictional force and is easily worn, manufacturing for coating layer formation while maintaining an excellent wear resistance effect Cost can be reduced.

  In addition, according to the present invention, for example, a plurality of rings (that is, a laminated body of steel hoops) provided in a belt portion of a CVT for a vehicle of a belt & pulley type can be configured. In other words, the belt-and-pulley type vehicle CVT includes a belt and a pulley. As is well known, the belt is constituted by a ring in which a large number of hoops (for example, 9 to 11 layers) are laminated and a large number of elements (frames) are continuously fitted between the rings. In general, in order to improve efficiency, a high friction coefficient is required between the belt and the pulley, while a low friction coefficient is required between the hoops constituting the ring to prevent cutting or the like. Therefore, when the friction coefficient between the belt and the pulley is increased by using lubricating oil, the friction coefficient between the hoops (the annular sliding member according to the present embodiment) is improved as a side effect. May decrease. That is, it has been difficult to satisfy these conflicting requirements using a kind of lubricating oil.

The conflicting requirements can be satisfied by the configuration of the present invention. For example, FIG. 5 shows a plurality of stacked metal hoops (annular sliding members) 50 to 54 constituting the ring 40 provided in the belt portion of the CVT. Of these hoops, only the hoops 50, 51 on the outer sides and three sheets 52, 53, 54 of the hoops sandwiched inside are partially shown. FIG. 6 schematically shows a partially enlarged sectional view thereof.
The covering layers 56 to 62 can be formed on one surface of the sliding surfaces of these hoops facing each other. As described above (that is, as shown in FIG. 1), the surfaces of the coating layers 56 to 62 facing each other have the same magnetic pole. According to the FOUPs 50 to 54, by making the magnetic pole directions of the covering layers 56 to 62 formed on the surfaces the same on both opposing surfaces, solid contact between the opposing hoops can be prevented. Thereby, it becomes a fluid lubrication environment between hoops, and it becomes easy to produce | generate the oil film by the said lubricating oil. As a result, the mutual frictional force between the two hoops can be reduced with a high effect. Therefore, cutting, breakage, etc. that may occur when the hoops 50 to 54 slip due to wear can be prevented. As shown in FIG. 6, the outer surfaces 64 and 65 (that is, the outer surface of the ring 40) of the hoops 50 and 51 on both outer sides do not become sliding surfaces, so that a coating layer may not be formed. Therefore, even if the frictional force between the belt and the pulley is increased by using the lubricating oil that increases the friction coefficient, the frictional force between the belt rings can be decreased.
The number of hoops constituting the ring used in the CVT belt is appropriately selected according to the application, and is usually 5 to 15, preferably about 8 to 12, but is not limited thereto.

Next, a method for manufacturing such a sliding structure will be described.
First, two or more sliding members having sliding surfaces that contact each other are prepared, and a matrix containing a magnetic material is applied to the sliding surfaces to form a coating layer.
As the magnetic material and the matrix, the same materials as described above can be used. The matrix may contain an abrasion resistance reinforcing material. As a means for applying this matrix, a conventionally known method can be applied without particular limitation. For example, a method in which a solution in which these are dispersed in a solvent is prepared, and this is applied to the sliding surface of the member by spray coating, roll coating, dipping (dip coating), or the like can be mentioned, but it is not limited thereto. In particular, spray coating capable of forming a uniform and thin coating layer is suitable.

Next, a magnetic field is applied to the sliding member on which the coating layer is formed. At this time, these sliding members are arranged so that the surfaces of the both sliding members facing each other have the same magnetic pole. That is, the surface of the coating layer is arranged in the same magnetic field direction in the magnetic field. Here, the means for applying the external magnetic field can be performed by a magnet or an electric current.
Then, if desired, the matrix of the coating layer is dried or cured. As the curing means, any conventionally known means may be applied depending on the properties of the matrix, and is not particularly limited. For example, in the case of a thermosetting resin, it can be carried out by heating at about 80 to 400 ° C.

Several examples relating to the present invention will be described below, but the present invention is not intended to be limited to those shown in the examples.
<Example 1>
(1) A solution was prepared by adding 5% by mass of magnetic powder and 5% by mass of hard particles to a base solution in which polyamide-imide resin was dissolved as a binder using N-methyl-2-pyrrolidone and methyl ethyl ketone as solvents. . In addition, the following were used for the polyamideimide resin, magnetic powder, and hard particles.
・ Polyamideimide resin; trade name “Polyamideimide resin 1000” (manufactured by Polyplastics Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
・ Hard particles: SiC (average particle size of 1-2 μm)
(2) After stirring the solution prepared in (1), this solution was spray coated on the sliding surface of the test piece.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 200 ° C. for 30 minutes, and the magnetic powder (magnetic Material) and a coating layer (average thickness: 10 μm) containing hard particles.
(4) A mating sliding member was produced in the same manner.

<Example 2>
(1) A solution was prepared by adding 5% by mass of magnetic powder to a base solution in which N-methyl-2-pyrrolidone and methyl ethyl ketone were used as solvents and a polyamideimide resin was dissolved as a binder. The following materials were used for the polyamideimide resin and the magnetic powder.
・ Polyamideimide resin; trade name “Polyamideimide resin 1000” (manufactured by Polyplastics Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
(2) After stirring the solution prepared in (1), this solution was spray coated on the sliding surface of the test piece.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 200 ° C. for 30 minutes, and the magnetic powder (magnetic A coating layer (average thickness: 10 μm) containing the material was formed.
(4) A mating sliding member was produced in the same manner.

<Example 3>
(1) An aqueous solution was prepared by adding 5% by mass of magnetic powder to a base aqueous solution in which colloidal silica was dispersed using water as a solvent. The following aqueous base solution and magnetic powder were used.
Base aqueous solution; trade name “FJ294” (Grandex Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
(2) After stirring the solution prepared in (1), a test piece was immersed in this solution.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 100 ° C. for 15 minutes, and magnetic powder (magnetic A coating layer (average thickness: 5 μm) containing the material was formed.
(4) A mating sliding member was produced in the same manner.
<Comparative Example 1>
In Example 1, a sliding member without a coating layer was prepared.

<Test Example 1>
The effect of reducing the friction characteristics (friction coefficient) was evaluated using a commercially available thrust type friction (wear) characteristic tester. FIG. 7 shows a rough shape of a test sample used in the test machine. That is, in the test sample 100, a cylindrical test piece 103 (the end surface is the sliding surface 105) and a flat plate test piece 107 (the upper surface is the sliding surface 109) are arranged to overlap each other. The coefficient of friction was measured by applying a predetermined pressure P and sliding the test piece 103 at a predetermined rotational sliding speed R.
In the test, on the sliding surfaces 105 and 109 of the test pieces 103 and 107, those having the coating layer of Example 1 or 2 and those having no coating layer as Comparative Example 1 were prepared. The test method was as follows.
(1) A trial oil in which only an antioxidant was added to 150N base oil was applied to the sliding surface.
(2) The oil temperature was heated to 100 ° C.
(3) Rotational speed S: The pressure P applied between the sliding surfaces was increased from 5 MPa to 10 MPa at 0.3 m / sec.
(4) A friction test for 60 minutes was performed under a constant load (10 MPa), and the change with time of the friction coefficient was evaluated.

FIG. 8 is a graph showing the test results obtained in Test Example 1, that is, changes with time in the friction coefficients of Examples 1 and 2 and Comparative Example 1. Compared with Comparative Example 1, in Examples 1 and 2, the coefficient of friction is significantly reduced from the beginning of the test, and thus it is understood that the friction reducing effect is excellent. That is, in Examples 1 and 2, the coating layer is formed on the end surface between the opposing test pieces. For this reason, the contact pressure between each end face is relieved by the repulsive magnetic force, the direct solid contact by each end face is reduced, and the contact area (ie, fluid lubrication area) through the oil (150N base oil) is increased. It was confirmed that the friction was reduced.
In addition, when Examples 1 and 2 are compared, in Example 2 that does not contain hard particles, the friction coefficient slightly increases with sliding time, whereas in Example 1 that contains hard particles, the change with time of the friction coefficient. It can be seen that is almost unacceptable. Therefore, it has been confirmed that the hard particles are included, the wear resistance is higher, and therefore the friction coefficient reduction effect is improved.

<Example 4>
In this embodiment, for example, as shown in FIG. 4, a coating layer is formed on the sliding surfaces of the cylinder and the piston of the vehicle engine portion.
[Formation of coating layer in cylinder bore]
(1) An aqueous solution was prepared by adding 5% by mass of magnetic powder and 3% by mass of hard particles to an aqueous base solution in which colloidal silica was dispersed using water as a solvent. The following aqueous base solution, magnetic powder, and hard particles were used.
Base aqueous solution; trade name “FJ294” (Grandex Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
Hard particles: Al ₂ O ₃ (average particle diameter of 1 to 2 μm)
(2) After stirring the aqueous solution prepared in (1), this solution was spray coated in the vicinity of the top and bottom dead center of the cylinder bore.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 100 ° C. for 15 minutes, and magnetic powder (magnetic Material) and a coating layer (average thickness: 15 μm) containing hard particles.

[Formation of coating layer on outer periphery of piston skirt]
(1) A solution was prepared by adding 5% by mass of magnetic powder and 5% by mass of hard particles to a base solution in which polyamide-imide resin was dissolved as a binder using N-methyl-2-pyrrolidone and methyl ethyl ketone as solvents. . The following materials were used for the polyamideimide resin, magnetic powder, and hard particles.
・ Polyamideimide resin; trade name “Polyamideimide resin 1000” (manufactured by Polyplastics Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
・ Hard particles: SiC (average particle size of 1-2 μm)
(2) After stirring the solution prepared in (1), this solution was spray-coated on the piston skirt.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 200 ° C. for 30 minutes, and the magnetic powder (magnetic Material) and a coating layer (average thickness: 10 μm) containing hard particles.

<Comparative example 2>
In Example 4, a cylinder and a piston that did not form a coating layer according to the present invention were prepared.
<Comparative Example 3>
In Example 4, the resin coating was applied only to the piston skirt without forming the coating layer according to the present invention on the cylinder and the piston. The resin coating used was a polyamide-imide resin with molybdenum disulfide (MoS ₂ ) and polytetrafluoroethylene (PTFE) added.

<Test Example 2>
The friction coefficient reduction effect of the sliding structure composed of the cylinder and the piston manufactured in Example 4 and Comparative Examples 2 and 3 was evaluated by motoring using a single cylinder engine. The test method was implemented by the average of test rotation speed at the friction loss average effective pressure in engine rotation speed 500rpm-2000rpm. The engine oil used was a commercially available 5W-30 oil, SL, and the test oil temperature was 100 ° C.

  FIG. 9 shows the test results obtained in Test Example 2. That is, the friction loss average effective pressure of Comparative Example 2 was set to the reference value “1”, and Example 4 and Comparative Example 3 showed the ratio. It can be seen that the friction loss average effective pressure ratio of Example 4 is significantly reduced as compared with Comparative Example 2 and Comparative Example 3 having the resin coating layer. That is, in Example 4, since the coating layer is formed between the opposing cylinder bore and the outer peripheral surface of the piston skirt, the pressure between the sliding surfaces is relieved by the repulsive magnetic force, It was confirmed that friction was reduced by reducing the direct solid contact area and increasing the contact area (ie, fluid lubrication area) via the oil (engine oil).

<Example 5>
In this embodiment, as shown in FIG. 5, for example, coating layers are formed on the sliding surfaces of the two hoops that constitute the ring included in the belt of the belt-and-pulley type vehicle CVT.
[Hoop manufacturing]
(1) A solution was prepared by adding 5% by mass of magnetic powder and 3% by mass of hard particles to a base solution in which N-methyl-2-pyrrolidone and methyl ethyl ketone were used as solvents and polyamideimide resin was dissolved as a binder. . The following materials were used for the polyamideimide resin, magnetic powder, and hard particles.
・ Polyamideimide resin; trade name “Polyamideimide resin 1000” (manufactured by Polyplastics Co., Ltd.)
Magnetic powder; trade name “FH-800” (manufactured by Toda Kogyo Co., Ltd., average particle size: 1.2 μm)
・ Hard particles: SiC (average particle size of 1-2 μm)
(2) After stirring the solution prepared in the above (1), this solution was spray-coated on one inner peripheral surface and the other outer peripheral surface of a separately prepared steel hoop.
(3) In a magnetic field (at this time, the direction of the magnetic field is applied so that the N pole of the magnetic powder is arranged on the sliding surface), it is cured in an oven at 200 ° C. for 30 minutes, and the magnetic powder (magnetic Material) and a coating layer (average thickness: 10 μm) containing hard particles.
(4) A ring was formed by overlapping two hoops so that the coating layers face each other.

<Comparative example 4>
In Example 5, what did not form a coating layer was used.

<Test Example 3>
In order to compare the effect of reducing friction loss between the hoops of Example 5 and Comparative Example 4, the test was performed with two hoops. That is, the testing machine is configured to be able to measure the torque transmitted from the inner hoop to be driven to the outer hoop. The friction reduction effect was evaluated from the torque loss reduction effect. In this test, commercially available CVTF (that is, continuously variable transmission oil) was used as the test oil. The test oil temperature was 100 ° C. The surface pressure and the relative speed between the two hoops were the environment at the time of starting acceleration of the actual CVT.

  FIG. 10 shows the results obtained in Test Example 3. That is, the torque loss of the comparative example 4 is set to the reference value “1”, and the example 5 shows the ratio. It can be seen that the torque loss ratio of Example 5 is significantly reduced as compared with Comparative Example 4. That is, in Example 5, the coating layer is formed between the contacting hoops, so that the pressure between the surfaces is relieved by the repulsive magnetic force, and the direct solid contact between the sliding surfaces is reduced. It was confirmed that the friction area was reduced and the torque loss was reduced by increasing the contact area (ie, fluid lubrication area) via the oil (CVTF).

  The preferred embodiments of the present invention have been described in detail above, but these are only examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the above-described embodiments. In addition, the technical elements described in the present specification or the drawings exhibit technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. In addition, the technology illustrated in the present specification or the drawings achieves a plurality of objects at the same time, and has technical utility by achieving one of the objects.

  The present invention can be applied to the production and use of various sliding structures without any particular limitation. In particular, it is suitable for providing a sliding structure (for example, engine, CVT) used in a vehicle.

It is explanatory drawing which shows typically the structure of the sliding structure of this invention. It is explanatory drawing which shows typically the suitable aspect of the coating layer in the sliding structure of this invention. It is explanatory drawing which shows typically the structure of the piston and engine of the vehicle engine part in one embodiment. It is explanatory drawing which shows typically the structure of the piston of the vehicle engine part in another embodiment, and an engine. It is explanatory drawing which shows typically the structure of the hoop (annular sliding member) which comprises the ring in CVT for belt & pulley system vehicles in one embodiment. FIG. 6 is a sectional view taken along line VI-VI in FIG. 5. It is explanatory drawing which shows typically the structure of the test sample utilized for the friction characteristic testing machine used in the Example. It is a graph which compares the result of the friction characteristic test of an Example and a comparative example. It is a graph which compares the result of the friction characteristic test of another Example and a comparative example. It is a graph which compares the result of the friction characteristic test of another Example and a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sliding structure 3, 5 ... Sliding member 7, 9, 34, 35, 37, 38, 56-62 ... Cover layer 11, 13 ... Magnetic material 12, 14 ... Matrix 15, 17 ... Cover layer Surface 21 ... Hard particles 23 ... Hard fiber 30 ... Cylinder 32 ... Piston 40 ... CVT ring 50-54 ... Hoop constituting CVT ring

Claims (14)

A sliding structure comprising at least two sliding members having sliding surfaces in contact with each other,
A coating layer made of a matrix containing dispersed magnetic materials is formed on the two opposing sliding surfaces, respectively.
A sliding structure characterized in that the surfaces of the coating layers facing each other have the same magnetic pole.   The sliding structure according to claim 1, wherein surfaces of the facing coating layers each have an N pole.   The sliding member according to claim 1, wherein the magnetic material includes ferrite and / or rare earth.   The sliding member according to any one of claims 1 to 3, wherein the magnetic material contained in the matrix is in the form of particles and has an average particle diameter in the range of 0.5 to 5 µm.   The sliding structure according to any one of claims 1 to 4, wherein an average thickness of the coating layer is in a range of 5 to 50 µm.   The sliding structure according to any one of claims 1 to 5, wherein the matrix further includes a wear resistance reinforcing material.   The sliding structure according to claim 6, wherein the reinforcing material includes nonmagnetic hard particles and / or nonmagnetic hard fibers. The sliding structure according to claim 7, wherein the hard particles or fibers include SiO ₂ and / or Al ₂ O ₃ .   The sliding structure according to claim 7, comprising carbon fibers as the hard fibers.   The sliding structure according to any one of claims 1 to 9, wherein one of the at least two sliding members constitutes a piston of a vehicle engine portion, and the other constitutes a cylinder.   11. The sliding structure according to claim 10, wherein the covering layer is formed at least near the top and bottom dead center of the skirt portion outer peripheral surface of the piston and the inner peripheral surface of the cylinder. .   The sliding structure according to any one of claims 1 to 9, wherein the at least two sliding members constitute a ring provided on a belt of a vehicle CVT. A method of manufacturing a sliding structure comprising at least two sliding members having sliding surfaces that contact each other,
Preparing the at least two sliding members;
Forming a coating layer by applying a matrix containing dispersed magnetic materials on the sliding surfaces of the sliding members that are in contact with each other;
Applying a magnetic field to the magnetic material to make the surfaces of the respective coating layers of the sliding surfaces in contact with each other have the same magnetic pole;
The manufacturing method of a sliding structure containing.   The manufacturing method according to claim 13, wherein a magnetic field is applied to the magnetic material by disposing the sliding member in a predetermined magnetic field direction in an external magnetic field.

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