JP2007239936A - Method of manufacturing sintered hydrodynamic bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To comparatively easily and stably manufacture a sintered hydrodynamic bearing, further reducing or blocking pore internal gaps caused by a contraction phenomenon following hardening of impregnated resin by a small number of processes while maintaining quality. <P>SOLUTION: The method of manufacturing the sintered hydrodynamic bearing has a resin sealing process of sequentially carrying out resin impregnation for impregnating a monomer of anaerobic resin mainly composed of ester acrylate or methacrylate in pores of a porous sintered body, excessive resin cleaning for cleaning excessive resin adhered to the porous sintered body, and resin hardening for maintaining the porous sintered body after resin cleaning at a hardening temperature of resin or more to harden the monomer of anaerobic resin impregnated in the pores. The resin sealing process is carried out plural times, and in at least the last resin sealing process, resin impregnating operation is carried out by using a monomer of anaerobic resin containing 0.1-1mass% organic peroxide. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a sintered dynamic pressure bearing manufacturing method in which pores of a porous sintered body are sealed among sintered bearings suitable for a disk drive spindle motor and the like.

  Recent motors for information devices are required to have low noise, mass productivity, and low cost as well as high rotational accuracy and high speed stability from the viewpoint of high recording density and high speed information processing. Such required performance is also imposed on the bearing that supports the shaft. As a bearing structure, for example, a sintered bearing is provided with various dynamic pressure generating grooves on the bearing surface, and is further fixed in the housing and lubricated. There has been provided an oil-filled one that supports a shaft in a non-contact manner by the action of a dynamic pressure generating groove when the shaft rotates.

  In such a sintered dynamic pressure bearing, pores on the bearing surface and the like are blocked or reduced in order to further increase the dynamic pressure action. In addition to the method of forming a sintered dynamic pressure bearing at a high density, this sealing treatment can be performed by sealing the bearing by various blasting or tumbling treatments, or by impregnating and hardening resin in the pores of the sintered body. The method to do is employ | adopted (patent document 1 grade | etc.,). In addition, the method of impregnating and curing the resin in the pores of the sintered body is performed by the procedures of resin impregnation, excess resin removal, resin curing, organic monomer type impregnating agent, organic polymer type impregnating agent, solvent A cut type impregnating agent and an aqueous emulsion type impregnating agent are used (Patent Document 2, etc.). Furthermore, after the resin is impregnated and cured in the pores of the sintered body and sealed, the gap in the pores caused by the resin's curing shrinkage is reduced by plastic processing that places the sintered body in the mold and applies pressure. Or it has also been proposed to close (Patent Document 3).

Japanese Patent Laid-Open No. 11-062948 JP 07-216411 A JP 2002-333023 A

  The above-mentioned method for forming a sintered dynamic pressure bearing at a high density involves a problem in that the amount of strain accumulated in the molded body is large and the dimensional accuracy is deteriorated because the pressure applied when compressing the raw material powder is increased. There is. In this case, even if the dimensions are corrected by re-compression, the material is high in density, so it is difficult to deform and cannot be corrected with high accuracy. Also, the method of sealing the bearings by various blasting and tumbling processes is difficult to supply media such as blasting into the bearings due to the downsizing of dynamic pressure bearings used in information equipment. There is a problem that the shape of the dynamic pressure groove formed on the inner diameter surface and / or the end surface of the bearing is impaired.

  On the other hand, the method of sealing the pores of the sintered body using a resin does not have the above-mentioned problems, and the production efficiency is relatively better than other sealing methods. Along with the variation, it is difficult to stabilize the surface opening ratio or the degree of sealing due to the fluctuation of the shrinkage rate when the resin impregnated in the pores is cured. For example, when lubricating oil is supplied as a fluid to a bearing unit incorporating a sintered hydrodynamic bearing, if the degree of sealing varies, the amount of oil absorbed by the sintered hydrodynamic bearing also varies partially. It causes the worst situation that the oil is partially insufficient or easily cut off. In other words, in a sintered dynamic pressure bearing, if the entire pores including the pores inside the bearings as well as the pores on the bearing surface are impregnated with resin, partial dispersion in the amount of oil absorption can be suppressed. The oil absorption cannot be stabilized by the fluctuation of the shrinkage rate, that is, the surface opening ratio.

  In addition, in the method of Patent Document 3, the gaps in the pores resulting from the curing shrinkage of the resin and the like are sealed by plastic working in order to overcome the above-described problems, but plastic processing is newly added. Therefore, the increase in manufacturing costs is inevitable. As a countermeasure, it is conceivable that the plastic processing step after the resin impregnation and the dynamic pressure groove forming step on the bearing surface are combined in order to prevent an additional mechanical step called plastic processing. However, in that case, the resin cured in the pores of the sintered body impairs the deformability of the sintered body, and the dynamic pressure grooves cannot be formed with high accuracy.

  An object of the present invention is to solve the above problems. Specifically, sintering that enables stable production of sintered hydrodynamic bearings with reduced or closed pore gaps caused by the shrinkage phenomenon associated with the curing of the impregnated resin, with fewer steps, and relatively easily maintaining quality. The object is to provide a method of manufacturing a hydrodynamic bearing.

  The method for producing a sintered hydrodynamic bearing according to the present invention is anaerobic, mainly composed of acrylic acid ester or methacrylic acid ester in the pores of a porous sintered body (for example, having a porosity of 5 to 20%). Resin impregnation operation for impregnating resin monomer, excess resin washing operation for washing excess resin adhering to the surface of the porous sintered body, and maintaining the porous sintered body after washing the excess resin above the resin curing temperature In the manufacturing method of a sintered dynamic pressure bearing having a resin sealing step of sequentially performing a resin curing operation for sequentially curing the anaerobic resin monomer impregnated in the pores, the resin sealing step is performed a plurality of times, and at least the last The resin impregnation operation in the resin sealing step is performed using an anaerobic resin monomer containing 0.1 to 1% by mass of an organic peroxide.

  In the above invention method, when the anaerobic resin monomer is blocked from air (atmosphere containing oxygen), free radicals are formed by the influence of metal ions, and these free radicals spontaneously start polymerization and cure. When it is a liquid resin or adhesive and contains 0.1 to 1% by mass of organic oxide, it reacts easily with metal ions in the air blocking state and becomes active in the pores of the porous sintered body. Causes a polymerization reaction.

  In the first aspect of the present invention, the monomer containing the organic peroxide is impregnated again in the gap generated by the resin curing and shrinking in the resin curing operation, and therefore the monomer is actively polymerized to seal the pores. The sealing can be performed reliably and stably. The sintered hydrodynamic bearing produced according to the present invention has the pores of the sintered body completely sealed, so that even when lubricating oil or the like is used as the fluid, the amount of absorbed lubricating oil is extremely small and the amount of absorbed oil The variation in the pressure is stable, and there is an excellent effect that no dynamic pressure is lost during use.

  In the invention of claim 2, the polymerization reaction starts at a relatively high temperature when 0.1 to 0.5% by mass of an azo compound is contained as a monomer of an anaerobic resin used for at least the first resin impregnation operation. Therefore, as the impregnating agent, the pores inside the porous sintered body and the depth of the pores are entered. In other words, if the polymerization reaction becomes active at a low temperature, for example, only the inlet side of the pores is sealed at the initial stage of the impregnation operation, and it becomes impossible to enter the inside of the pores. To do.

In the invention of claim 3, since the impregnating agent used in the last resin impregnation operation is a component adjusted so that the polymerization reaction becomes active from the beginning, it is used for each resin sealing step (resin impregnation operation) performed a plurality of times. When using the same anaerobic resin monomer, the porous sintered body should be impregnated under conditions that suppress the polymerization reaction in at least the first resin impregnation operation, that is, under reduced pressure of 10 ² to 10 ³ Pa. The inside of the pores, so that they penetrate deeply into the pores so as to be impregnated.

  The invention of claim 4 is significant in that specific examples of the organic peroxide are given. When the invention according to claim 5 contains a curing accelerator composed of an organometallic compound of 1% by mass or less, for example, the pore surface is covered by the first resin impregnation operation, and metal ions are difficult to reach. In such a case, it is ensured that the resin is impregnated and cured.

  In the invention of claim 6, when the porous sintered body contains 20% by mass or more of Cu, the above polymerization reaction can be activated in the presence of Cu which is easily ionized, and the addition form of Cu is 3 When the copper foil powder of ˜30% by mass is used, the ratio of Fe exposed on the pore surface decreases, and the exposure amount of Cu that easily generates metal ions increases, so that the above polymerization reaction can be more activated. . The invention of claim 7 clarified that it is preferable that the sintered dynamic pressure bearing has undergone a dimensional adjustment recompression step and a dynamic pressure groove formation recompression step before the resin sealing step in order to improve the quality. It has significance.

  The method for producing a sintered hydrodynamic bearing according to the present invention includes a resin impregnation operation in which pores of a porous sintered body are impregnated with a monomer of an anaerobic resin mainly composed of methacrylate, and adhere to the surface of the porous sintered body. Resin curing operation for cleaning the excess resin (liquid), and curing the anaerobic resin monomer impregnated in the pores while maintaining the porous sintered body after the excess resin cleaning at a temperature higher than the curing temperature of the resin A resin sealing step for sequentially performing the operations is included. And the principal part uses the monomer of the anaerobic resin containing 0.1-1 mass% organic peroxide for the resin impregnation operation in the 2nd resin sealing process while performing the resin sealing process twice. To do.

  Here, the target sintered dynamic pressure bearing is designed by a compacting process for compressing and forming the raw material powder, a sintering process for sintering the obtained green compact, and the obtained sintered body by plastic working such as sizing After being produced by a recompression process or the like formed into a bearing shape, the pores are sealed through the resin sealing process of the present invention. Here, as the pore sealing state, it is preferable that 100% of the resin is filled with respect to the pore volume. However, if the pore volume is 90% or more with respect to the pore volume, the absorption amount of the lubricating oil is extremely small. There is no problem in use because the variation in absorption amount is stable.

  During the resin sealing step, an anaerobic resin monomer mainly composed of acrylic acid ester or methacrylic acid ester is used as the impregnating agent in the resin impregnation operation. Resin mainly composed of acrylic acid ester or methacrylic acid ester has low reactivity with lubricating oil and has an appropriate strength. Therefore, a sintered hydrodynamic bearing in which pores are sealed with this resin, When used in lubricating oil, it is preferable because it does not react with the lubricating oil and deteriorate the lubricating properties, or the resin does not deteriorate and peel and fall into the lubricating oil. An anaerobic resin monomer mainly composed of acrylic acid ester or methacrylic acid ester is acrylic acid or methacrylic acid ester known as an anaerobic resin monomer, specifically polyglycol dimethacrylate, epoxy acrylate, epoxy methacrylate It is a monomer containing acrylic acid or methacrylic acid ester such as urethane acrylate or urethane methacrylate and, if necessary, other acrylic acid ester or methacrylic acid ester. In addition, in this application, you may contain the other monomer aiming at modification | reformation of anaerobic resin other than these monomers in the range which does not impair the effect of invention.

  Anaerobic resins generally contain a peroxidation catalyst as an organic peroxide, and the peroxidation catalyst is converted into free radicals by metal ions in a state where air (atmosphere containing oxygen) is blocked. A monomer is polymerized into a polymer by a group to form a so-called cross-linked strong polymer. On the other hand, since it is stable in the atmosphere by the supply of constant oxygen, free radicals are not generated and the polymerization reaction is not started. In such anaerobic resins, the peroxide catalyst has an important meaning as an initiator for the polymerization reaction. That is, when an anaerobic resin monomer is used as the impregnating agent, if the peroxidation catalyst is likely to react with metal ions, the polymerization reaction proceeds actively, but it is difficult to react with metal ions. The polymerization reaction proceeds slowly.

  The resin impregnation operation is performed by a vacuum impregnation method. Specifically, for example, the porous sintered body is immersed in the anaerobic resin monomer in the impregnation tank, the air in the pores of the porous sintered body is removed by depressurizing the impregnation tank, and then up to atmospheric pressure. Method of returning and impregnating the monomer into the pores by suction, with the porous sintered body placed on the stage in the impregnation tank, and reducing the pressure in the impregnation tank to air in the pores of the porous sintered body And then dropping the entire stage and immersing the porous sintered body in the anaerobic resin monomer in the impregnation tank, and then returning to atmospheric pressure and impregnating the monomer into the pores by suction. In these vacuum impregnation methods, the pressure may be further increased after returning to atmospheric pressure.

  By the way, it is preferable that the sealed state of the sintered dynamic pressure bearing is completely sealed with resin to the pores inside the porous sintered body and the back side of the pores. That is, in the aspect in which only the pores near the surface portion and the surface, and the pore inlet side are sealed, the pores inside the porous sintered body and the back side of the pores are degassed in the resin impregnation operation and are in a reduced pressure state. Therefore, when the sealing hole is torn during use, there is a risk that the lubricating oil is sucked into the pores and the lubricating oil necessary for fluid lubrication is insufficient.

  Therefore, in the resin impregnation operation, when the polymerization reaction is instantly activated, only the surface portion and the pores near the surface and the inlet side of the pores are sealed at the initial stage of the resin impregnation, and the impregnating agent is a porous sintered body. It is not preferable because it cannot reach the inner pores or the inner side of the pores. From this point, as the impregnating agent used for the first resin impregnation operation, an anaerobic resin containing a methacrylic acid ester as a main component and containing 0.1 to 0.5% by mass of an azo compound is used. It is preferable to impregnate with a monomer. For example, Resinol 90C manufactured by Henkel Co., Ltd. described in Patent Document 1 is an anaerobic resin containing a methacrylic acid ester as a main component and an azo compound (2,2-azobis) as a peroxidation catalyst. Since it is started at a temperature of 90 ° C. or higher, it is suitable for impregnation up to the pores inside the porous sintered body and the back side of the pores.

  However, with such an impregnating agent that suppresses the polymerization reaction, the resin undergoes polymerization shrinkage in the heat-curing operation after washing the excess resin, so that the generation of gaps due to the shrinkage is unavoidable. The gap can be completely filled by performing the resin impregnation operation a plurality of times, but performing the impregnation operation a number of times increases time and cost.

  Therefore, the manufacturing method of the present invention fills the gap with fewer resin impregnation operations so that the volume ratio of the resin to the pores is 90% or more. Therefore, at least in the first resin impregnation operation, among the pores of the porous sintered body The impregnating agent is filled as much as possible into the pores inside the sintered body and the back side of the pores. At the same time, for the gap generated by heat curing, the impregnating agent used in the second and subsequent resin impregnation operations is different from the first impregnating agent or under different conditions from the impregnation conditions such as the first decompression. By doing so, it can be surely sealed. In other words, the contrivance of the present invention resides in a configuration in which an anaerobic resin monomer containing 0.1 to 1% by mass of an organic peroxide is used as an impregnation agent used in at least the final resin impregnation operation. An organic peroxide is one that easily reacts with metal ions among the peroxide catalysts, and is suitable for curing by causing a polymerization reaction in the pores of the porous sintered body.

  In order to carry out the above polymerization reaction in an appropriate range, the organic peroxide added to the anaerobic resin needs to be 0.1% by mass or more. If it is less than 0.1% by mass, the polymerization reaction is not sufficiently active, and the re-sealing of the pores becomes insufficient. Moreover, when it adds exceeding 1.0 mass%, said polymerization reaction will become too active and resin will solidify on the porous sintered compact surface, and it will become difficult to remove the excess resin part.

  In order to carry out such a polymerization reaction more actively, it is preferable to use hydroperoxides among organic peroxides. Hydroperoxides include t-butyl hydroperoxide, cumene hydroperoxide, di-isopropyl peroxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, benzoyl peroxide These may be used selectively or in combination.

  Further, the following points are important from the material configuration of the porous sintered body. When the porous sintered body contains 20% by mass or more of Cu, the above polymerization reaction can be performed actively. That is, since Cu is an element easily ionized, the polymerization reaction in the second resin sealing step (resin curing operation) can be actively performed. Moreover, about the addition form of Cu, it is recommended to use 3-30 mass% copper foil powder. The reason is, for example, when manufacturing a copper-sintered porous sintered body, if 3 to 30% by mass of copper foil powder is used as the raw material powder, the copper foil powder adheres to the iron powder surface and covers the iron powder surface. It becomes a state. In a porous sintered body obtained by compacting and sintering such a raw material powder, the ratio of Fe exposed to the inner wall of the pores is greatly reduced, and the exposed amount of Cu that easily generates metal ions is increased. Therefore, even if there is little Cu content, the supply amount of Cu ion can be earned and said polymerization reaction can be activated further. However, if the use of copper foil powder is less than 3% by mass, the effect of coating the iron powder is poor, and conversely, even if it exceeds 30% by mass, no further improvement in the effect of iron powder coating is observed. It contributes to the cost increase. For this reason, 3-30 mass% is an appropriate range for the amount of copper foil powder.

From the first resin impregnation operation, an anaerobic resin monomer containing, as a main component, an acrylic ester or methacrylic ester used in the final resin impregnation operation and 0.1 to 1% by mass of an organic peroxide. Can be used. In this case, since the resin for sealing the pores is the same component, the adhesiveness is improved as compared with the case of impregnating components having different resin strengths. However, since the impregnating agent used in the final resin impregnation operation is a component adjusted so that the polymerization reaction becomes active, when used in the first resin impregnation operation, the impregnation is performed under conditions that suppress the polymerization reaction. Thus, it is necessary to enter and fill the impregnating agent to the pores inside the porous sintered body and the back side of the pores. The suppression of the polymerization reaction is preferably controlled by the following method. That is, as described above, the anaerobic resin starts the polymerization reaction by changing the oxygen of the organic peroxide (peroxidation catalyst) to a free radical by a metal ion in a state where external oxygen is blocked. If the amount of external oxygen is increased, the polymerization reaction can be suppressed. Specifically, the pressure in the resin impregnation operation is set to 10 ² to 10 ³ Pa, and a certain amount of oxygen in the impregnation tank is allowed to remain, so that acrylic acid ester or methacrylic acid ester is the main component. Even if an anaerobic resin monomer containing ˜1% by mass of organic peroxide is used, it becomes possible to reliably enter and fill the impregnating agent to the pores inside the porous sintered body and the back side of the pores. . In the final resin impregnation operation, it is necessary to perform the polymerization reaction actively to seal the gap, and therefore it is necessary to carry out under a reduced pressure lower than 10 ² Pa.

  After the resin impregnation, the excess resin adhering to the surface is removed by washing with an excess resin washing operation, and then the impregnated resin is polymerized by heating the porous sintered body impregnated with the resin by the resin curing operation. And harden. At this time, in the last resin impregnation operation, the gap generated in the previous resin impregnation operation must be sealed. However, when an anaerobic resin monomer containing an organic peroxide is used, the polymerization reaction is caused. Since it can be activated actively, the heating temperature for resin curing may be lowered, and there is also an advantage that blowout of uncured monomers accompanying thermal expansion of the resin during the temperature rise from room temperature to the heating temperature is reduced.

  Moreover, as an impregnating agent used for resin impregnation operation, you may use together the hardening accelerator which consists of an organometallic compound of 1 mass% or less which is used with general anaerobic resin. In particular, in the last resin impregnation operation, most of the pore inner walls are coated in the previous resin impregnation operation, and metal ions are difficult to reach, so that it is recommended to use a curing accelerator made of an organometallic compound. However, since addition of an excessive organometallic compound causes an excessive polymerization reaction during the above-described monomer impregnation, the addition should be 1% by mass or less. Examples of the organometallic compound used include lithium dimethylcuprate, diacetylacetone copper, calcium carbide, and phenyllithium. In addition, in this invention, an organic and / or inorganic filler, a viscosity modifier, a stabilizer, etc. can be mix | blended in the range which does not impair the effect of invention.

  The above resin impregnation operation may be performed after the sintering step when, for example, the dynamic pressure groove is formed at the time of compaction molding and the dimensional adjustment and the recompression step for forming the dynamic pressure groove are not performed later. When the re-compression process is performed after the process, the resin cured in the pores of the porous sintered body reduces the deformability of the sintered body, making it difficult to prepare accurately. And after each recompression step of forming the dynamic pressure groove.

  The excess resin cleaning operation completely removes excess resin. However, when a very small amount of excess resin remains, after the resin impregnation operation, the medium is about φ0.1 to 1.0 mm, preferably 0. It is preferable to completely remove the remaining resin by mechanically hitting the bearing surface by magnetic barrel processing or electromagnetic barrel processing using a stainless pin of about 1 to 0.6 mm.

  The sintered dynamic pressure bearing obtained by the above method for producing a sintered dynamic pressure bearing is an anaerobic resin mainly composed of acrylic ester or methacrylic ester in the pores of the interior, from the back of the pore to the inlet. For example, even when the polymer is completely impregnated and cured and is supplied to the bearing unit and supplied with the lubricating oil, it is excellent in that there is no loss of dynamic pressure and absorption of the lubricating oil.

  In the examples, iron powder, electrolytic copper powder, copper foil powder, tin powder, and graphite powder were prepared as raw material powders, and added and mixed at the blending ratio shown in Table 1 to adjust the raw material powder, and then the inner diameter was 2.5 mm. The compact was molded into a bearing shape having an outer diameter of 7 mm and a height of 5 mm so that the density ratio would be 85%, and was sintered in an ammonia decomposition gas atmosphere at 770 ° C. for 30 minutes. Subsequently, the sintered body is subjected to a recompression process for the purpose of adjusting dimensions and a dynamic pressure groove forming recompression process for imparting five arc-shaped dynamic pressure shapes to the bearing inner diameter surface. A porous sintered body was produced.

  Resinol 90C (trade name) manufactured by Henkel, which contains polyglycol dimethacrylate as a main component as an anaerobic resin and contains 0.3% by mass of an azo compound (2,2-azobis) as a peroxidation catalyst. (Hereinafter referred to as anaerobic resin 1). Moreover, Henkel PMS-50E (trade name) containing polyglycol dimethacrylate as a main component as an anaerobic resin and 0.8% by mass of cumene hydroperoxide as a peroxidation catalyst was prepared (hereinafter referred to as anaerobic resin). 2).

  About 55 porous sintered compacts produced by the above, the resin sealing process was carried out 11 pieces each with the combination of the anaerobic resin shown in Table 2, and the pressure reduction pressure, and samples AE were produced. The resin sealing step was performed according to the following procedure. That is, in the resin impregnation operation, the porous sintered body is placed on the stage in the impregnation tank, the pressure in the impregnation tank is reduced, air in the pores of the porous sintered body is removed, and then the stage is lowered. The porous sintered body on the stage was immersed in the anaerobic resin monomer in the impregnation tank, and then impregnated by applying pressure and sucking the monomer into the pores. After the resin impregnation, the excess resin liquid adhering to the surface of the porous sintered body is washed, and then 90 ° C for the anaerobic resin 1 and 50 ° C for the anaerobic resin 2 (both recommended by the manufacturer) The anaerobic resin monomer impregnated in the pores while being held in the warm water was cured.

  One sample was cut and polished from each of the prepared samples for tissue observation, and the sealed state of the cross section was observed with a microscope for the surface layer portion and the inside. The results are shown in the “sealed state” column of Table 2. In addition, this observation result was described as "(circle)" when the sealing by resin was confirmed by microscopic observation, and "x" when resin did not exist.

  In addition, the weight of each of the remaining 10 samples of each sample was measured, then immersed in a lubricating oil filled in a beaker, depressurized to 5 Pa, and then returned to atmospheric pressure. Then, the weight was measured again and tested. A lubricating oil absorption test was conducted repeatedly to examine the difference in weight of each sample before and after (presence or absence of absorption of lubricating oil). When no increase in weight (absorption of lubricating oil) was observed in the test with 5 repetitions, the test was repeated 5 more times (10 times in total), and the presence or absence of an increase in weight was similarly examined. As for the test results at this time, “x” when absorption (increase in weight) of lubricating oil was observed for 10 samples, “△” when absorption of lubricating oil was observed for several samples, and an increase in weight at all. Is not recognized, it was evaluated as “◯” and described in the column “Presence / absence of oil absorption” in Table 2.

  From Table 2, in the first resin sealing step, the samples (samples A to C) using the anaerobic resin 1 containing an azo compound as a peroxidation catalyst all resin up to the pores inside the porous sintered body. Was impregnated and sealed. On the other hand, sample D, which uses anaerobic resin 2 containing an organic peroxide as a peroxidation catalyst and has been subjected to a resin sealing step under a reduced pressure of 50 Pa, has a polymerization reaction that has been active since the beginning of impregnation, resulting in surface pores. It was confirmed that the resin was impregnated at the initial stage and the resin was not impregnated to the pores inside the porous sintered body. However, even in the same anaerobic resin 2, in the sample E in which the resin sealing step was performed under the reduced pressure of 200 Pa, the polymerization reaction was suppressed by the increase of the oxygen partial pressure, and the pores inside the porous sintered body were reduced. It was confirmed that the resin could be filled up to.

From Table 2, in Sample A (conventional example) in which the resin sealing step was performed only once using the anaerobic resin 1, absorption of the lubricating oil was performed for all of the 10 samples after the lubricating oil absorption test was performed five times. Although it was not confirmed by microscopic observation, it was confirmed that a gap was generated between the pores and the resin. In addition, Sample B, which was subjected to the resin sealing step twice using the anaerobic resin 1, was found to absorb the lubricating oil after the five lubricating oil absorption tests, and occurred in the first sealing step. It was confirmed that the gaps that were made could not be completely sealed in the second resin sealing step. Furthermore, in Sample D in which the resin sealing step was performed only once using the anaerobic resin 2, the absorption of the lubricating oil was not confirmed in the fifth lubricating oil absorption test. Later, absorption of lubricating oil was observed for one sample, and it was confirmed that there was a problem with the stability of the sealed state. On the other hand, in Samples C and E in which the second resin sealing step was performed using the anaerobic resin 2, even if the lubricating oil absorption test was repeated ten times, the absorption of the lubricating oil was not confirmed, and a good and stable sealing was achieved. It was confirmed to be in a hole state. From the above, when the pores of the porous sintered body are sealed only by two resin sealing steps, the second resin impregnation operation is performed using an anaerobic resin monomer containing an organic peroxide. It was confirmed that the pores can be sealed reliably and stably.

Claims (7)

Resin impregnation operation in which pores of the porous sintered body are impregnated with a monomer of an anaerobic resin mainly composed of acrylic acid ester or methacrylic acid ester, and excess resin adhering to the surface of the porous sintered body is washed away Resin cleaning step, resin sealing step of sequentially performing resin curing operation of curing the anaerobic resin monomer impregnated in the pores while maintaining the porous sintered body after washing the excess resin at a temperature higher than the curing temperature of the resin In the manufacturing method of the sintered hydrodynamic bearing,
The resin sealing step is performed a plurality of times, and at least the resin impregnation operation in the last resin sealing step is performed using an anaerobic resin monomer containing 0.1 to 1% by mass of an organic peroxide. A method for manufacturing a sintered hydrodynamic bearing.   The sintering operation according to claim 1, wherein the resin impregnation operation in at least the first resin sealing step is performed using an anaerobic resin monomer containing 0.1 to 0.5% by mass of an azo compound. Pressure bearing manufacturing method. The resin impregnation operation in the first resin sealing step is performed by using a monomer of an anaerobic resin containing 0.1 to 1% by mass of an organic peroxide and reducing the pressure to 10 ² to 10 ³ Pa. The manufacturing method of the sintered hydrodynamic bearing of Claim 1.   The organic peroxide is t-butyl hydroperoxide, cumene hydroperoxide, di-isopropyl peroxide, p-menthane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, benzoyl peroxide The method for producing a sintered hydrodynamic bearing according to any one of claims 1 to 3, wherein the hydroperoxide is at least one kind of hydroperoxide.   The sintering motion according to any one of claims 1 to 4, wherein the monomer of the anaerobic resin whose main component is the methacrylate contains a curing accelerator composed of 1% by mass or less of an organometallic compound. Pressure bearing manufacturing method.   The porous sintered body is made of a copper iron-based material, and the raw material powder is made of a material containing 3 to 30% by mass of copper foil powder, and the Cu content is 20% by mass or more. The method for producing a sintered hydrodynamic bearing according to any one of claims 1 to 5. Prior to the resin sealing step, the porous sintered body is moved by a dimension adjustment recompression process for adjusting the dimensions of the porous sintered body, and plastic working on the inner diameter surface and / or end surface of the porous sintered body. The method for producing a sintered hydrodynamic bearing according to any one of claims 1 to 6, wherein a hydrodynamic groove forming and recompressing step of providing a pressure generating groove is performed.