JP2009008132A - Multilayered sliding member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multilayered sliding member that displays the same level of a friction wear characteristic as a conventional multilayered sliding member in sliding when a lubricating agent such as grease exists, and displays a superior friction wear characteristic without causing a stick slip in sliding under a dry friction condition. <P>SOLUTION: The multilayered sliding member is equipped with a back plate 1 composed of a steel plate, a sintered porous metal layer 2 integrally formed on the surface of the back metal 1, and a sliding layer 3 comprising a synthetic resin composition filled in a pore of the sintered porous metal layer 2 and covering the surface of the layer. The synthetic resin composition contains 1-15 pts.wt. phosphate and 5-30 pts.wt. tetrafluoroethylene resin with respect to 100 pts.wt. of nylon 11 or nylon 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention includes a backing metal, a porous metal sintered layer integrally formed on the surface of the backing metal, and a synthetic resin composition sliding layer filled in the pores of the porous metal sintered layer and coated on the surface. The present invention relates to a multilayer sliding member.

Japanese Patent Publication No.31-2452 Japanese Patent Publication No. 61-52322 No. 01-27495 JP 2006-56205 A

  A multi-layer sliding member comprising a backing metal made of a steel plate, a porous metal sintered layer integrally formed on the surface of the backing metal, a pore of the porous metal sintered layer and a synthetic resin layer filled and coated on the surface ( Patent Document 1 and Patent Document 2) describe a shaft in various mechanical devices in the form of a cylindrical bearing bush formed by winding the synthetic resin layer inside, a so-called wound bush, or in the form of a sliding plate. Widely used as a support means for smooth support.

  As the synthetic resin that fills the pores of the porous metal sintered layer integrated on the back metal and is coated on the surface, ethylene tetrafluoride resin or polyacetal resin is mainly used under dry friction conditions. In addition, it exhibits excellent low friction properties in the presence of a lubricant such as grease.

When these multi-layer sliding members are applied to reciprocating sliding applications, for example, a rack guide in a rack and pinion type steering device for automobiles (Patent Document 3), a synthetic resin composition mainly composed of tetrafluoroethylene resin is used. synthetic resin in the multilayered sliding member comprising a sliding layer comprising a load (surface pressure) wear resistance is significantly reduced in use in loading conditions exceeding 100 kgf / cm ^2, also made mainly of polyacetal resin The multi-layer sliding member provided with the sliding layer made of the composition has a drawback that the wear resistance is remarkably lowered when the load (surface pressure) is used under a load condition exceeding 150 kgf / cm ² .

In order to solve the above-described drawbacks, the present inventor has proposed a multilayer sliding member in which the synthetic resin composition forming the sliding layer contains at least 11 nylon or 12 nylon (Patent Document 4). This multilayer sliding member exhibits excellent wear resistance even when used under high load conditions where the load (surface pressure) exceeds 150 kgf / cm ² .

  However, this multi-layer sliding member exhibits excellent wear resistance in the presence of grease and other lubricants, but wear resistance is impaired when used under dry friction conditions, and the coefficient of static friction There is a large difference between the coefficient of friction and the coefficient of dynamic friction, which often causes stick slip (adhesion-slip), resulting in a new problem of generating abnormal frictional noise caused by stick slip.

  The present invention has been made in view of the above-mentioned points. The object of the present invention is equivalent to the multilayer sliding member described in Patent Document 4 in sliding under the presence of a lubricant such as grease. An object of the present invention is to provide a multilayer sliding member that exhibits friction and wear characteristics and exhibits excellent friction and wear characteristics without causing stick slip even when sliding under dry friction conditions.

  The multilayer sliding member of the present invention includes a back plate made of a steel plate, a porous metal sintered layer integrally formed on the surface of the back metal, and the pores of the porous metal sintered layer are filled and coated on the surface The synthetic resin composition comprises 1 to 15 parts by weight of phosphate and 5 to 4 parts of ethylene tetrafluoride resin per 100 parts by weight of 11 nylon or 12 nylon. 30 weight part is mix | blended, It is characterized by the above-mentioned.

  In the multilayer sliding member of the present invention, a sliding layer made of a synthetic resin composition in which a phosphate and an ethylene tetrafluoride resin are blended at a predetermined ratio with respect to 11 nylon or 12 nylon as a main component, The difference between the coefficient of static friction and the coefficient of dynamic friction is small, and it exhibits excellent friction and wear characteristics in sliding under the presence of grease and other lubricants and dry friction conditions. No abnormal frictional noise is generated.

  In the multilayer sliding member of the present invention, a fatty acid amide may be added to the synthetic resin composition as an additional component in a proportion of 5 parts by weight or less.

  The fatty acid amide plays a role as a lubricant and contributes to the low friction property of the sliding layer in cooperation with the tetrafluoroethylene resin in the synthetic resin composition. The fatty acid amide plays a role of promoting the spreadability of the synthetic resin composition when filling the pores of the porous sintered metal layer and coating the surface with the synthetic resin composition.

  In the multilayer sliding member of the present invention, at least one selected from the group of solid lubricants of graphite, molybdenum disulfide, tungsten disulfide, and boron nitride as an additional component in the synthetic resin composition is 5 parts by weight or less. You may mix | blend in the ratio. These solid lubricants exhibit the effect of improving the wear resistance of the sliding layer.

  The multilayer sliding member of the present invention is applied as a so-called wound bush in the form as it is, as a sliding plate, a sliding plate, or in a form wound in a cylindrical shape with the sliding layer inside.

  According to the present invention, the difference between the coefficient of static friction and the coefficient of dynamic friction is small, exhibits excellent friction and wear characteristics in sliding under the presence of lubricating oil such as grease and dry friction conditions, and causes stick slip. Therefore, it is possible to provide a multilayer sliding member that does not generate abnormal frictional noise due to the stick-slip.

  Hereinafter, the multilayer sliding member of the present invention will be described in detail.

  The multilayer sliding member of the present invention includes a back plate made of a steel plate, a porous metal sintered layer integrally formed on the surface of the back metal, and the pores of the porous metal sintered layer are filled and coated on the surface The synthetic resin composition comprises 1 to 15 parts by weight of phosphate and 5 to 4 parts of ethylene tetrafluoride resin per 100 parts by weight of 11 nylon or 12 nylon. 30 parts by weight is blended.

  In such a multi-layer sliding member, 11 nylon or 12 nylon, which is the main component of the synthetic resin composition, has the characteristics that the water absorption is smaller than other nylon resins and the powder coating property is excellent. Specifically, 11 nylon “Rilsan (trade name)” manufactured by Atofina Japan, 12 nylon “Daiamide (trade name)” manufactured by Daicel Degussa, and the like can be mentioned.

As a phosphate in the synthetic resin composition, a metal salt selected from any one of the group of metal salts of diphosphate, tertiary phosphate, pyrophosphate and metaphosphate, and mixtures thereof Can be mentioned as a preferred example. Of these, metal salts of pyrophosphoric acid and metaphosphoric acid are preferable. As the metal, an alkali metal and an alkaline earth metal are preferable, and lithium (Li), calcium (Ca), and magnesium (Mg) are particularly preferable. Specifically, lithium triphosphate (Li ₃ PO ₄ ), tricalcium phosphate [Ca ₃ (PO ₄ ) ₂ ], calcium hydrogen phosphate [CaHPO ₄ .2H ₂ O] or anhydride (CaHPO ₄ ), Magnesium hydrogen phosphate (MgHPO ₄ .3H ₂ O) or anhydride (MgHPO ₄ ), lithium pyrophosphate (Li ₄ P ₂ O ₇ ), calcium pyrophosphate (Ca ₂ P ₂ O ₇ ), magnesium pyrophosphate (Mg ₂ P ₂ O ₇ ), lithium metaphosphate (LiPO ₃ ), calcium metaphosphate [Ca (PO ₃ ) ₂ ], magnesium metaphosphate [Mg (PO ₃ ) ₂ ] and the like.

  These phosphates themselves are not substances that exhibit lubricity like solid lubricants such as graphite, but when blended in a synthetic resin composition, the sliding material and the mating material can be used in sliding. The effect of promoting the film forming property of the lubricating coating of the synthetic resin composition on the surface (sliding friction surface) is exhibited. When these phosphates are blended in a small amount, for example, 1 part by weight with respect to the synthetic resin composition, an effect of promoting the film forming property of the lubricating film of the synthetic resin composition on the surface of the counterpart material starts to appear, Until this effect is maintained. However, if it exceeds 15 parts by weight, the amount of the lubricating coating formed on the surface of the counterpart material becomes too large, and there is a possibility that the wear resistance is lowered. Therefore, the blending amount of the phosphate is 1 to 15 parts by weight, preferably 3 to 7 parts by weight with respect to 100 parts by weight of 11 nylon or 12 nylon as the main component.

  As the tetrafluoroethylene resin (hereinafter abbreviated as “PTFE”) in the synthetic resin composition, compared with the high molecular weight PTFE by molding powder (hereinafter abbreviated as “high molecular weight PTFE”) and radiation irradiation. PTFE having a reduced molecular weight, easy to grind and good dispersibility and mainly used as an additive material (hereinafter abbreviated as “low molecular weight PTFE”) can be used. As high molecular weight PTFE, “Teflon (registered trademark) 7-J”, “Teflon (registered trademark) 7A-J”, “Teflon (registered trademark) 70-J” manufactured by Mitsui DuPont Fluorochemical Co., Ltd., Daikin Industries, Ltd. “Polyflon M-12 (trade name)” manufactured by Asahi Glass Co., Ltd., “Fullon G163 (trade name)”, “Fullon G190 (trade name)”, etc.

  Low molecular weight PTFE includes “TLP-10F (trade name)” manufactured by Mitsui DuPont Fluoro Chemical Co., Ltd. and “Lublon L-5 (trade name)” manufactured by Daikin Industries, Ltd. Name) ”,“ Full-on L169J (trade name) ”and“ KTL-8N (trade name) ”manufactured by Kitamura.

  In the present invention, both the high molecular weight PTFE and the low molecular weight PTFE can be used, but the low molecular weight PTFE is preferred. These PTFEs play a role of imparting low friction to the sliding layer made of the synthetic resin composition and minimizing the difference between the static friction coefficient and the dynamic friction coefficient. The blending amount of PTFE is 5 to 30 parts by weight, preferably 10 to 20 parts by weight, based on 100 parts by weight of 11 nylon or 12 nylon as the main component. When the blending amount is less than 5 parts by weight, it is difficult to impart low friction to the sliding layer, and when it exceeds 30 parts by weight, the spreadability of the synthetic resin composition is deteriorated and the formation of the sliding layer is difficult.

  In this invention, you may mix | blend fatty acid amide as an additional component with respect to the synthetic resin composition which consists of an above-described phosphate, a tetrafluoroethylene resin, and the remainder 11 nylon or 12 nylon.

  The fatty acid amide works as a lubricant to give low friction to the sliding layer in cooperation with the PTFE, and at the same time, promotes the spreadability at the time of filling and covering the porous metal sintered layer of the synthetic resin composition. To do. Specific examples of the fatty acid amide include ethylene bis erucamide, ethylene bis oleate amide, ethylene bis stear amide, oleic amide, stear amide, eruc amide, etc. Among them, ethylene bis stear amide is preferable. . The blending amount of the fatty acid amide is 5 parts by weight or less, preferably 0.5 to 4 parts by weight with respect to 100 parts by weight of 11 nylon or 12 nylon as the main component.

  In the present invention, the synthetic resin composition may further contain at least one selected from the group of solid lubricants of graphite, molybdenum disulfide, tungsten disulfide, and boron nitride. The blending amount of the solid lubricant is 5 parts by weight or less, preferably 0.5 to 3 parts by weight with respect to 100 parts by weight of 11 nylon or 12 nylon as the main component. These solid lubricants exhibit the effect of improving the wear resistance of the sliding layer made of the synthetic resin composition. If the blending amount is less than 0.5 parts by weight, an effect cannot be expected to improve the wear resistance of the sliding layer. If the blending amount exceeds 5 parts by weight, the strength of the sliding layer is impaired, and the wear resistance is decreased.

  Next, a multilayer having a sliding layer formed by filling and covering the pores of the porous metal sintered layer integrally formed on the surface of the backing metal made of a steel plate and the synthetic resin composition having the above-described component composition on the surface. A method for manufacturing the sliding member will be described.

  As the back metal, a general structural rolled steel plate is used. Although it is preferable to use a continuous strip provided as a hoop material by winding it in a coil shape, the steel plate is not necessarily limited to a continuous strip, and a strip cut to an appropriate length can also be used. These strips may be subjected to copper plating or tin plating as necessary to improve the corrosion resistance. The thickness of the back metal made of this steel plate is 0.5 to 1.0 mm.

  The metal powder forming the porous metal sintered layer integrally formed on the surface of the back metal is made of a sieve of approximately 100 mesh, such as bronze, lead bronze or phosphor bronze excellent in friction wear characteristics of the metal itself. Passing copper alloy powder is used, but powders other than copper alloy, such as aluminum alloy and iron, can be used depending on the purpose. The metal powder may be in the form of a lump, a sphere, or an irregular shape. This porous metal sintered layer must be firmly bonded to the alloy powders and to the strip of the steel sheet, and to have a certain thickness and the required porosity. The thickness of the sintered porous metal layer is preferably about 0.15 to 0.40 mm, more preferably 0.2 to 0.3 mm, and the porosity is about 10% by volume or more, especially 15 to A volume of 40% is recommended.

  The sliding layer is a synthetic resin composition comprising a mixture of 11 nylon or 12 nylon powder and the phosphate and tetrafluoroethylene resin, or a mixture in which the fatty acid amide and / or solid lubricant is further blended. A synthetic resin composition is used.

  The multilayer sliding member of the present invention is manufactured through the following steps (a) to (b).

  (A) A synthetic resin composition is sprayed and supplied onto a porous sintered metal layer integrally formed on a backing metal plate, and the thickness of the synthetic resin composition is adjusted to a uniform thickness by a leveler. To do. (B) The back metal treated in the step (a) is held for 6 minutes in a heating furnace heated to a temperature of 220 ° C. higher than the melting point of 11 nylon (melting point 187 ° C.) or 12 nylon (melting point 177 ° C.), Next, the synthetic resin composition is filled into the pores of the porous metal sintered layer through a pair of heat rollers heated to a temperature of 80 ° C., and the size is adjusted and the surface of the porous metal sintered layer is adjusted. A sliding layer is formed by coating to obtain a desired multilayer sliding member.

  In the multilayer sliding member obtained through the steps (a) to (b), the thickness of the porous metal sintered layer is 0.23 to 0.25 mm, and the thickness of the sliding layer made of the synthetic resin composition Is 0.05 to 0.30 mm. The multilayer sliding member obtained in this way is cut into an appropriate size and used as a sliding plate in a flat plate state, or rounded and used as a cylindrical wound bush.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example, unless the summary is exceeded.

Examples 1-4
“Rilsan (trade name)” manufactured by Atofina Japan Co., Ltd. is used as 11 nylon, and “Daiamide (trade name)” manufactured by Daicel Degussa is used as 12 nylon, respectively. 3-5 parts by weight of at least one of tribasic calcium phosphate, calcium pyrophosphate and magnesium metaphosphate as phosphates, “Fluon L150J (trade name)” manufactured by Asahi Glass Co., Ltd. and “KTL-” manufactured by Kitamura Co., Ltd. as PTFE 8N (trade name) "was blended with 10 to 15 parts by weight, and these were fed into a Henschel mixer and mixed by stirring to obtain a mixed powder of a synthetic resin composition.

  A porous metal (bronze) sintered layer (thickness 0.24 mm) integrally formed on a back metal (thickness 0.50 mm) made of a metal thin plate with the mixed powder of the synthetic resin composition thus obtained It was sprayed and supplied to the top, and the thickness of the synthetic resin composition was adjusted to a uniform thickness with a leveler. Such a backing metal is held in a heating furnace heated to a temperature of 220 ° C. for 6 minutes, and then passed between a pair of heat rollers heated to a temperature of 80 ° C. to pass the synthetic resin composition to the porous metal sintered layer. The porous metal sintered layer was coated with a synthetic resin composition to form a sliding layer (thickness: 0.23 mm) to obtain a multilayer sliding member. .

  FIG. 1 is a cross-sectional view showing a multilayer sliding member obtained in this manner. In the figure, reference numeral 1 is a back plate made of a steel plate, 2 is a porous metal sintered layer, and 3 is porous metal sintered. It is a sliding layer made of a synthetic resin composition filled and coated on the pores and the surface of the layer 2. The multilayer sliding member whose dimensions were adjusted was cut to obtain a rectangular test piece having a side of 30 mm.

Examples 5-8
3 to 5 parts by weight of at least one of tribasic calcium phosphate, calcium pyrophosphate and magnesium metaphosphate as a phosphate with respect to 100 parts by weight of 11 nylon (same as the previous example) or 12 nylon (same as the previous example) As a PTFE, 10-15 parts by weight of either “Fluon L150J (trade name)” manufactured by Asahi Glass Co., Ltd. or “KTL-8N (trade name)” manufactured by Kitamura Co., Ltd., and ethylene bis-stearic acid amide 4 as a fatty acid amide One part by weight of graphite or molybdenum disulfide as a solid lubricant was blended with 1 part by weight, and these were fed into a Henschel mixer and mixed by stirring to obtain a mixed powder of a synthetic resin composition. Thereafter, a rectangular test piece having a side of 30 mm was obtained in the same manner as in the above example.

Comparative Examples 1-2
11 Synthetic resin composition containing 5 parts by weight of calcium pyrophosphate as a phosphate and synthetic resin composition containing 1 part by weight of graphite as a solid lubricant with respect to 100 parts by weight of 11 nylon (same as the above example) Was supplied into a Henschel mixer and mixed by stirring to obtain a mixed powder of a synthetic resin composition. Thereafter, a rectangular test piece having a side of 30 mm was obtained in the same manner as in the above example.

Comparative Examples 3-4
As a PTFE, a high molecular weight PTFE for fine powder manufactured by Daikin Industries, Ltd. [Polyflon F201 (trade name)], a synthetic resin composition containing 43 parts by weight of lead with respect to 100 parts by weight of PTFE, and 100 parts by weight of the same PTFE as described above In contrast, synthetic resin compositions each containing 10 parts by weight of calcium pyrophosphate and 29 parts by weight of lead as phosphates were prepared, and these synthetic resin compositions were supplied into a Henschel mixer and mixed by stirring. 20 parts by weight of a petroleum solvent was blended with 100 parts by weight of the mixed powder and mixed at a temperature (15 ° C.) below the room temperature transition point of PTFE to obtain a synthetic resin composition having wettability.

The resultant synthetic resin composition is sprayed and supplied onto a porous metal (bronze) sintered layer (thickness 0.24 mm) formed on a steel back metal (thickness 0.50 mm) made of a thin metal plate, respectively, and synthesized. Rolling was performed with a roller so that the thickness of the sliding layer of the resin composition was 0.23 mm, and a multilayer board in which the pores and the surface of the sintered layer were filled and coated with the synthetic resin composition was obtained. The obtained multilayer board was kept in a hot air drying furnace heated to a temperature of 200 ° C. for 5 minutes to remove the solvent, and then the sliding layer made of the dried synthetic resin composition was applied to a pressure of 400 kgf / cm ² by a roller. The thickness of the sliding layer of the synthetic resin composition coated on the sintered layer was 0.10 mm.

  About the square-shaped test piece produced in above-mentioned Examples 1-8 and Comparative Examples 1-4, the friction-abrasion characteristic was evaluated with the following test method.

(1) Reciprocating sliding test I
The static friction coefficient, dynamic friction coefficient, and wear amount were measured under the conditions shown in Table 1. About the amount of wear, it showed by the dimensional change amount of the sliding layer after completion | finish of test time [20 hours].

(Table 1)
Sliding speed 3m / min
Load 300kgf
Test time 20 hours Lubrication No lubrication (dry)
Counterpart material High carbon chromium bearing steel (SUJ2)
Surface roughness of mating material Ra (arithmetic mean roughness) 0.1

(2) Reciprocating sliding test II
The static friction coefficient, dynamic friction coefficient, and wear amount were measured under the conditions shown in Table 2. About the amount of wear, it showed by the dimensional change amount of the sliding layer after completion | finish of test time [20 hours].

(Table 2)
Sliding speed 3m / min
Load 500kgf
Test time 20 hours Lubrication Mineral oil-based grease [“One Louver MO (trade name)” manufactured by Kyodo Yushi Co., Ltd.] is applied to the sliding surface before the test. Counterpart material High carbon chromium bearing steel (SUJ2)
Surface roughness of mating material Ra (arithmetic mean roughness) 0.3

(3) Thrust test The friction coefficient and the amount of wear were measured under the conditions described in Table 3. For the friction coefficient, the friction coefficient at the time of stability until the end of the test after 1 hour from the start of the test is shown, and the wear amount is shown by the dimensional change amount of the sliding layer after the end of the test time.

(Table 3)
Sliding speed 5m / min
Load (surface pressure) 19.6 MPa (200 kgf / cm ² )
Test time 20 hours Lubrication No lubrication (dry)
Mating material Carbon steel for machine structure (S45C)
Surface roughness of mating material Ra (arithmetic mean roughness) 0.15

  Tables 4 to 6 show the results of the reciprocating sliding tests I and II and the thrust test described above.

注）表６中の＊印は、試験開始後１時間で摩擦係数が０．４を超えたため、その時点で試験を中止した。

Note) In Table 6, the mark * indicates that the coefficient of friction exceeded 0.4 one hour after the start of the test, so the test was stopped at that time.

  From the above test results, the multi-layer sliding member consisting of Examples 1-8 showed a very small difference between the static friction coefficient and the dynamic friction coefficient in the reciprocating sliding test, and showed stable sliding throughout the test time, There was no stick-slip and no abnormal frictional noise due to stick-slip was observed. On the other hand, the multilayer sliding members of Comparative Examples 1 to 4 showed a large wear amount under all test conditions. In particular, the multilayer sliding member of Comparative Example 3 was 1 hour after the start of the test in the thrust test. Since the friction coefficient exceeded 0.4 and the test was stopped, the amount of wear could not be measured.

  As described above, the multi-layer sliding member of the present invention does not generate stick slip even when sliding under the presence of a lubricant such as grease and dry friction conditions, and generates an abnormal frictional sound caused by stick slip. Demonstrates excellent friction and wear characteristics without occurrence.

It is sectional drawing of the multilayer sliding member of a preferable example of this invention.

Explanation of symbols

1 Back metal 2 Porous metal sintered layer 3 Sliding layer

Claims (6)

  A backing metal made of a steel plate, a porous metal sintered layer integrally formed on the surface of the backing metal, and a sliding layer made of a synthetic resin composition filled in the pores of the porous metal sintered layer and coated on the surface The synthetic resin composition comprises 1-15 parts by weight of phosphate and 5-30 parts by weight of ethylene tetrafluoride resin with respect to 100 parts by weight of 11 nylon or 12 nylon. Is a multilayer sliding member.   The multilayer sliding member according to claim 1, wherein the phosphate is selected from at least one of the group of metal salts of diphosphoric acid, triphosphoric acid, pyrophosphoric acid, and metaphosphoric acid.   The phosphate is any of lithium triphosphate, calcium triphosphate, calcium hydrogen phosphate, magnesium hydrogen phosphate, lithium pyrophosphate, calcium pyrophosphate, magnesium pyrophosphate, lithium metaphosphate, calcium metaphosphate and magnesium metaphosphate The multilayer sliding member according to claim 1 or 2 selected from any one of these.   The multilayer sliding member according to any one of claims 1 to 3, wherein a fatty acid amide is blended in an amount of 5 parts by weight or less as an additional component in the synthetic resin composition.   The fatty acid amide is selected from any one of ethylene bis erucamide, ethylene bis oleate, ethylene bis stear amide, oleic amide, stear amide, erucic amide. Multi-layer sliding member.   6. The synthetic resin composition according to claim 1, wherein at least one selected from the group of solid lubricants of graphite, molybdenum disulfide, tungsten disulfide, and boron nitride is added as an additional component in an amount of 5 parts by weight or less. A multilayer sliding member according to claim 1.

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