JP2005155655A - Sliding bearing manufacturing method - Google Patents

Sliding bearing manufacturing method Download PDF

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Publication number
JP2005155655A
JP2005155655A JP2003382848A JP2003382848A JP2005155655A JP 2005155655 A JP2005155655 A JP 2005155655A JP 2003382848 A JP2003382848 A JP 2003382848A JP 2003382848 A JP2003382848 A JP 2003382848A JP 2005155655 A JP2005155655 A JP 2005155655A
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bearing
sintered
bearing housing
sizing
press
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Tadayoshi Yano
忠義 矢野
Hideo Yomo
英雄 四方
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Resonac Corp
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Hitachi Powdered Metals Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a sliding bearing assembly having a sintered bearing pressed and fixed into a bearing housing, with extremely small eccentricity and good dimensional accuracy. <P>SOLUTION: This sliding bearing manufacturing method comprises a step of forming and sintering metal material powder into the predetermined shape of the bearing 10, a step of mounting and fixing the sintered bearing 10 into the bearing housing 20, a step of using a cutting tool 30 for cutting the inner peripheral face of the sintered bearing 10 with the outer periphery of the bearing housing 20 as a reference face, and a step of using a mandrel 40 for sizing the inner peripheral face of the cut sintered bearing. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、寸法精度及び精密な回転が要求されるモータ用として好適に用いることができる焼結合金製滑り軸受の製造方法に関する。   The present invention relates to a method for manufacturing a sintered alloy sliding bearing that can be suitably used for a motor that requires dimensional accuracy and precise rotation.

各種モータ等に用いられる焼結合金製の滑り軸受は、概ね、原料金属粉を圧粉成形および焼結し、焼結体をサイジングして所定寸法形状に仕上げる手順によって製造される。焼結合金製の軸受には、軸孔が滑らかな円形断面のものや、軸孔に油溜まりや動圧を発生する形状の複数の溝を備えたものがある。通常は多孔性の焼結合金であり潤滑油が含浸されたものである。また、動圧軸受の場合では、少なくとも軸孔面は高密度であるか塑性流動させて気孔が少ない状態とされ、摺動部に潤滑油や磁性流体を保持させて用いられる。   Sintered alloy sliding bearings used for various motors and the like are generally manufactured by a procedure in which raw metal powder is compacted and sintered, and the sintered body is sized and finished to a predetermined size and shape. Some bearings made of a sintered alloy have a circular cross-section with a smooth shaft hole, and some have a plurality of grooves in a shape that generates an oil reservoir or dynamic pressure in the shaft hole. Usually, it is a porous sintered alloy impregnated with lubricating oil. In the case of a dynamic pressure bearing, at least the shaft hole surface is made to have a high density or plastic flow so that there are few pores, and the sliding portion is used with lubricating oil or magnetic fluid held therein.

このような焼結合金製の軸受は、切削加工された軸受ハウジング内部に圧入される。圧入する際には、圧入によって変形する軸受内径寸法が所定寸法になるように、軸受の内径にマンドレルを装着することがある。また、圧入せずに、嵌合してボンド等により接着固定する場合もある。   Such a sintered alloy bearing is press-fitted into the machined bearing housing. When press-fitting, a mandrel may be attached to the inner diameter of the bearing so that the inner diameter of the bearing deformed by the press-fitting becomes a predetermined dimension. Moreover, it may be fitted and fixed by bonding or the like without being press-fitted.

軸受ハウジング内に装着された軸受には、回転する軸を支持する構造で使用されたり、反対に軸を中心に軸受ハウジング側が回転する構造のものがある。これらの軸受要素では、軸と軸受の関係における回転精度がより高いことが求められるので、圧入する前の軸受の寸法精度を確保するために金型を精密に製作したり、軸受ハウジングへの組み立て治具や工具の精度を吟味する等の製造技術によって対応しているが、次のような問題がある。   Some bearings mounted in the bearing housing are used in a structure that supports a rotating shaft, and conversely, the bearing housing side rotates around the shaft. These bearing elements are required to have higher rotational accuracy in the relationship between the shaft and the bearing. Therefore, in order to ensure the dimensional accuracy of the bearing before press-fitting, the mold is precisely manufactured or assembled to the bearing housing. This is handled by manufacturing techniques such as examining the accuracy of jigs and tools, but there are the following problems.

図２〜図６は従来技術を説明する縦断面図又は横断面図で、切削加工された軸受ハウジング２０内に焼結軸受が圧入された状態を誇張して示した模式図である。   2 to 6 are longitudinal sectional views or transverse sectional views for explaining the prior art, and are schematic views exaggeratingly showing a state in which a sintered bearing is press-fitted into a machined bearing housing 20.

図２は、軸受ハウジング２０の軸心２１に対して焼結軸受１０の軸心１１が傾いて圧入されているものを示している。サイジングされた寸法精度の高い焼結軸受１０を用い、圧入の際に矯正マンドレルを用いたとしても、圧入作業が不適切であればこのような例が発生してしまう。   FIG. 2 shows that the shaft center 11 of the sintered bearing 10 is inclined and press-fitted with respect to the shaft center 21 of the bearing housing 20. Even if the sized sintered bearing 10 with high dimensional accuracy is used and a correction mandrel is used for press-fitting, such an example will occur if the press-fitting operation is inappropriate.

図３は、２個の焼結軸受１２、１３が圧入されている構造であるが、焼結軸受１２、１３の内径と外径とが偏心しているため、二つの焼結軸受１２、１３の軸心１１、１１ａがずれてしまったものである。   FIG. 3 shows a structure in which two sintered bearings 12 and 13 are press-fitted. However, since the inner diameter and the outer diameter of the sintered bearings 12 and 13 are eccentric, The shaft centers 11 and 11a are shifted.

図４は、焼結軸受１４、１５の外形寸法にばらつきがあり、軸受ハウジング２０内に圧入した際の圧入代（焼結軸受１４、１５の外径寸法と軸受ハウジング２０の内径寸法との差）が異なるため、圧入した後の二つの焼結軸受１４、１５の内径に寸法差が生じてしまった形態である。圧入の際にマンドレルを用いてもスプリングバック量に差を生じるため矯正できない。   FIG. 4 shows that the outer dimensions of the sintered bearings 14 and 15 vary, and the press-fitting allowance (the difference between the outer diameter dimension of the sintered bearings 14 and 15 and the inner diameter dimension of the bearing housing 20 when pressed into the bearing housing 20 is shown. ) Are different from each other, so that a dimensional difference has occurred in the inner diameters of the two sintered bearings 14 and 15 after press-fitting. Even if a mandrel is used for press-fitting, there is a difference in the amount of springback, which cannot be corrected.

軸受ハウジングに円筒形状の焼結軸受を圧入すると共に、外周に軸方向へ延びる突条を備えたマンドレルを焼結軸受の軸孔に圧入して凸条により油溝を形成する技術がある（例えば引用文献１、２参照）。図５はこのような技術によって形成され軸方向に延びる複数の油溝１７を備えた軸受を示したものである。この焼結軸受１０は、図３で説明したと同様に偏心しているため、軸受ハウジング２０の軸心の中心２１と焼結軸受１０の軸孔中心１１がずれてしまったものである。   There is a technique in which a cylindrical sintered bearing is press-fitted into a bearing housing, and a mandrel having a protrusion extending in the axial direction on the outer periphery is press-fitted into a shaft hole of the sintered bearing to form an oil groove by a protruding line (for example, References 1 and 2). FIG. 5 shows a bearing having a plurality of oil grooves 17 formed by such a technique and extending in the axial direction. Since the sintered bearing 10 is eccentric as described with reference to FIG. 3, the center 21 of the shaft center of the bearing housing 20 and the center 11 of the shaft hole of the sintered bearing 10 are shifted.

また、図６は、軸方向に延びる油溝１８を有する軸受である（例えば引用文献３参照）。この軸受では外周が概ね三角形状をなす焼結軸受１０を準備し、軸受ハウジング２０内に圧入することによって焼結軸受１０を縮径させ、焼結軸受１０の比較的薄肉部１９が変形して拡径するのに伴って軸孔に溝１８を形成するものである。この技術は、焼結軸受１０の部分密度に差が生じたり、肉厚差等により複数の薄肉部１９の変形量が異なったりすると、軸孔形状が不均等になってしまうおそれがある。
特公昭４０−２００２号公報（第１−２頁、図１） 特公昭４２−１５４４７号公報（第１−２頁、図２） 特開平９−３２９１４６号公報（第２−７頁、図１） FIG. 6 shows a bearing having an oil groove 18 extending in the axial direction (see, for example, cited document 3). In this bearing, a sintered bearing 10 having a substantially triangular outer periphery is prepared, and the sintered bearing 10 is reduced in diameter by being press-fitted into the bearing housing 20, so that the relatively thin portion 19 of the sintered bearing 10 is deformed. The groove 18 is formed in the shaft hole as the diameter increases. In this technique, if the partial density of the sintered bearing 10 is different or the deformation amounts of the plurality of thin portions 19 are different due to a difference in thickness or the like, the shaft hole shape may be uneven.
Japanese Patent Publication No.40-2002 (page 1-2, FIG. 1) Japanese Examined Patent Publication No. 42-15447 (page 1-2, FIG. 2) JP-A-9-329146 (page 2-7, FIG. 1)

上述のような各種の状態及びこれらの組合せによって生じる寸法ばらつきや軸の偏心は、軸受の大きさにもよるが数μｍから十数μｍ程度になることがあり、サイジングしても矯正することが困難である。例えば、軸受ハウジング孔と焼結軸受の軸心とが偏心していると、回転軸支持構造では軸が軸受面に片当たりして組み付けられて、摩擦、摩耗、消費電力、寿命に影響を及ぼし、軸を中心に軸受側が回転する構造では、軸受ハウジング側が偏心回転し、振動、摩耗、寿命等に影響を及ぼすことになる。できるだけ寸法ばらつきや偏心が少ないように品質管理をして製作し組み立てるわけであるが、従来からの製造方法では精度向上が限界に達している。   Depending on the size of the bearing, the dimensional variation and shaft eccentricity caused by the various states as described above and combinations thereof may be several μm to several tens of μm, and can be corrected by sizing. Have difficulty. For example, if the bearing housing hole and the shaft center of the sintered bearing are eccentric, the shaft is assembled to the bearing surface in the rotating shaft support structure, affecting the friction, wear, power consumption, life, In a structure in which the bearing side rotates around the shaft, the bearing housing side rotates eccentrically, which affects vibration, wear, life, and the like. Production and assembly are performed with quality control so as to minimize dimensional variation and eccentricity as much as possible. However, improvement in accuracy has reached the limit in conventional manufacturing methods.

この発明は、焼結軸受を軸受ハウジングに圧入等で固着した滑り軸受ユニット１８を、更に良好な寸法精度で製造する方法を提供することを目的とする。   An object of the present invention is to provide a method for manufacturing a sliding bearing unit 18 in which a sintered bearing is fixed to a bearing housing by press-fitting or the like with better dimensional accuracy.

本発明は、上記問題点を解決するためになされたもので、金属原料粉を所定の軸受形状に成形及び焼結した焼結軸受素材を、軸受ハウジング内に装着固定し、軸受ハウジングの外周面を基準面としてこれに倣って焼結軸受素材の内周面を切削加工し、該切削加工された焼結軸受素材の内周面をサイジングすることを特徴とする滑り軸受の製造方法である。   The present invention has been made to solve the above-described problems. A sintered bearing material obtained by molding and sintering metal raw material powder into a predetermined bearing shape is mounted and fixed in the bearing housing, and the outer peripheral surface of the bearing housing is provided. In accordance with this, the inner peripheral surface of the sintered bearing material is cut according to this, and the inner peripheral surface of the cut sintered bearing material is sized.

この場合、前記内周面をサイジングする際には、軸方向に延びる凸条を外周に複数備えたマンドレルを用い、軸受内周面にサイジングにより軸方向に延びる複数の動圧溝を形成することとすれば好適である。また、上記方法は、焼結軸受素材の内周面を切削加工することにより切削面の気孔を減少させ、切削加工された焼結軸受素材の内周面をサイジングする工程によって軸受内周面の気孔をさらに減少させる技術手段を包含する。   In this case, when sizing the inner peripheral surface, a mandrel having a plurality of axially extending ridges on the outer periphery is used, and a plurality of dynamic pressure grooves extending in the axial direction are formed on the bearing inner peripheral surface by sizing. This is preferable. In addition, the above method reduces the pores of the cutting surface by cutting the inner peripheral surface of the sintered bearing material, and sizing the inner peripheral surface of the sintered bearing material that has been cut and processed. Includes technical means to further reduce pores.

また、この製造方法には、公知の技術を適宜付加することができる。例えば、
（ａ）焼結軸受端面に工具を押しつけて封孔処理すること
（ｂ）焼結軸受の気孔を封孔する手段として樹脂含浸する焼結軸受素材に含油させること
（ｃ）切削加工は軸受の軸孔の他に、必要に応じて軸受端面や軸受ハウジングの断面や段差部等を行うこと
（ｄ）切削加工やサイジングした後に洗浄すること
（ｅ）軸受ハウジングにスラスト受け板を固着すること
（ｆ）磁性流体潤滑や磁性流体シール構造の場合では軸受ハウジングに永久磁石を装着すること、或いは
（ｇ）軸受を磁性粒子が含有した焼結合金製にすること
等の手段を付加することができる。 Moreover, a well-known technique can be suitably added to this manufacturing method. For example,
(A) A tool is pressed against the end face of the sintered bearing and sealed (b) Oil impregnated into a sintered bearing material impregnated with resin as means for sealing pores of the sintered bearing (c) Cutting is performed on the bearing In addition to the shaft hole, if necessary, the bearing end face, the cross section of the bearing housing, the stepped portion, etc. are performed. (D) Cleaning is performed after cutting or sizing. (E) The thrust receiving plate is fixed to the bearing housing ( f) In the case of magnetic fluid lubrication or magnetic fluid seal structure, means such as mounting a permanent magnet on the bearing housing, or (g) making the bearing made of a sintered alloy containing magnetic particles can be added. .

本発明によれば、軸受ハウジングに圧入等で固着した焼結軸受の内径面を切削加工して軸受ハウジングの外周と同軸の軸受孔を形成した後、切削加工された内径面をマンドレルで矯正することとしたので、軸受内径の真円度および円筒度が精密であると共に、軸受ハウジングとの同軸度が著しく向上する。その結果、モータ等に用いたとき、回転精度に優れ、振動や摩耗の少ない等、品質が向上する。   According to the present invention, the inner diameter surface of the sintered bearing fixed to the bearing housing by press fitting or the like is cut to form a bearing hole coaxial with the outer periphery of the bearing housing, and then the cut inner diameter surface is corrected with the mandrel. As a result, the roundness and cylindricity of the bearing inner diameter are precise, and the coaxiality with the bearing housing is remarkably improved. As a result, when used in a motor or the like, the quality is improved, such as excellent rotational accuracy and less vibration and wear.

以下図面を参照して本発明の実施の形態を説明する。図１（ａ）〜図１（ｃ）は本発明の実施の形態を模式的に示した工程図である。
（１） 軸受ハウジングの製作
従来と同様に、ステンレス鋼材、青銅合金、アルミニウム合金等の材料を切削加工して軸受ハウジング２０を所定寸法に仕上げる。切削加工は、軸受ハウジング２０の外周面を基準面としてその内径及び端面が加工される。軸受ハウジング２０の内径寸法は焼結軸受１０の外径寸法に対して圧入の軸受締め代を考慮して決定される。圧入の軸受締め代は、焼結軸受の外形寸法が１０ｍｍ以下においては１０〜５０μｍ程度であるが、できるだけ小さくするのが望ましい。切削加工によって、軸受ハウジング２０は外周（外径）の軸心と内径の軸心を正確に一致させる。 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1A to FIG. 1C are process diagrams schematically showing an embodiment of the present invention.
(1) Manufacture of bearing housing As in the past, materials such as stainless steel, bronze alloy, and aluminum alloy are cut to finish the bearing housing 20 to a predetermined size. In the cutting process, the inner diameter and end face of the bearing housing 20 are processed with the outer peripheral surface of the bearing housing 20 as a reference surface. The inner diameter dimension of the bearing housing 20 is determined in consideration of the press-fit bearing tightening margin with respect to the outer diameter dimension of the sintered bearing 10. The bearing allowance for press-fitting is about 10 to 50 μm when the outer dimension of the sintered bearing is 10 mm or less, but is desirably as small as possible. By cutting, the bearing housing 20 accurately aligns the outer (outer diameter) axis and the inner diameter.

（２） 焼結軸受の製作
選定した組成及び密度の焼結合金からなる円筒状焼結軸受１０の素材を製作する。軸受素材１０は焼結されたままの状態、焼結体をサイジングしたもの、焼結体に樹脂含浸して気孔を封孔したもの、或いは粉末成形で高密度の圧粉体にしたりサイジングして高密度化して気孔が少ない焼結合金としたもの等を用いることができる。焼結軸受１０は図１（ａ）に矢印で示すように、軸受ハウジング２０内に装入される。 (2) Manufacture of sintered bearing A material of the cylindrical sintered bearing 10 made of a sintered alloy having a selected composition and density is manufactured. The bearing material 10 remains in a sintered state, a sintered body is sized, a sintered body is impregnated with resin and pores are sealed, or a powder compact is formed into a high-density green compact or sized. It is possible to use a sintered alloy having a higher density and fewer pores. The sintered bearing 10 is inserted into the bearing housing 20 as indicated by an arrow in FIG.

焼結軸受１０を軸受ハウジング２０内に嵌合してボンド等で固定する場合では、嵌合寸法精度が良好な方が固着のばらつきを少なくできるので、焼結軸受１０の外径をサイジングしたものを用いることが望ましい。また、焼結軸受１０の内径寸法の変化が少ないように約１０μｍ以下の締まり嵌めで軸受ハウジング２０内に圧入し、その際に軸受ハウジングの内径面又は焼結軸受１０の外径面に溝を設けて接着剤を塗布しておき、圧入と接着を併用する方法もある。   In the case where the sintered bearing 10 is fitted into the bearing housing 20 and fixed with a bond or the like, the better the fitting dimensional accuracy can reduce the variation in fixation, so that the outer diameter of the sintered bearing 10 is sized. It is desirable to use Further, the inner diameter of the sintered bearing 10 is pressed into the bearing housing 20 with an interference fit of about 10 μm or less so that a groove is formed on the inner diameter surface of the bearing housing or the outer diameter surface of the sintered bearing 10. There is also a method in which an adhesive is applied and the press-fitting and adhesion are used together.

圧入する場合では、サイジングされた焼結軸受１０を用いてもよいが、焼結されたままの軸受素材で充分である。焼結軸受１０の内周端面部は面取りしておくことが望ましい。   In the case of press-fitting, a sized sintered bearing 10 may be used, but a sintered bearing material is sufficient. It is desirable to chamfer the inner peripheral end surface portion of the sintered bearing 10.

動圧軸受における焼結軸受１０の動圧溝の形成は、圧粉成形の際にコアロッドによって溝形状を形成しておいてもよく、粉末成形の際に溝形状の一部を形成しておき、後のサイジングによって溝形状を完成する方法、及び焼結軸受素材では溝のない単純形状に製作しておき、後のサイジングによって溝形状を完成することとしてもよい。動圧溝をサイジングによって形成する場合は、溝形成の材料変形を気孔で吸収できる気孔を含んでいる焼結軸受素材が望ましい。   Formation of the dynamic pressure groove of the sintered bearing 10 in the dynamic pressure bearing may be performed by forming a groove shape with a core rod at the time of compacting, and forming a part of the groove shape at the time of powder molding. The groove shape may be completed by a subsequent sizing, and the sintered bearing material may be manufactured in a simple shape without grooves, and the groove shape may be completed by subsequent sizing. When the dynamic pressure groove is formed by sizing, a sintered bearing material including pores capable of absorbing the groove-forming material deformation by the pores is desirable.

（３） 軸受ハウジングへの固着
上記焼結軸受素材を軸受ハウジング内に装着固定する。具体的には
（ａ）軸受ハウジングに焼結軸受素材を圧入する
（ｂ）焼結軸受素材をを嵌め込んでボンド等の接着剤を用いて接着する
（ｃ）焼結軸受素材を圧入代を少なくして圧入すると共にボンド等の接着剤を用いて補強接着する、或いは、
（ｄ）カシメや溶接により固着される。 (3) Adhering to the bearing housing The sintered bearing material is mounted and fixed in the bearing housing. Specifically, (a) a sintered bearing material is press-fitted into the bearing housing, (b) the sintered bearing material is fitted and bonded using an adhesive such as a bond, and (c) the sintered bearing material is pressed into Press-fit with a small amount and reinforce and bond using an adhesive such as a bond, or
(D) It is fixed by caulking or welding.

焼結軸受素材を軸受ハウジングに装着するときは、焼結軸受素材を軸受ハウジングとマンドレルで案内することで傾きが防止される。   When the sintered bearing material is mounted on the bearing housing, the tilt is prevented by guiding the sintered bearing material with the bearing housing and the mandrel.

（４） 切削加工
図１（ｂ）に矢印で示すように軸受ハウジング２０の外径を基準面とし、焼結軸受１０の内径を切削刃物３０で切削加工し所定寸法に仕上げる。軸受素材の寸法精度は、粉末成形金型の組立て精度、焼結による変形などにより、ばらつきが大きいものとなっていても、切削加工によって軸受ハウジング２０の外径との同軸度、加工面の真円度および円筒度を高精度に仕上げることができる。精度は１μｍ程度にできる。焼結軸受１０がサイジングされたもの、或いは軸受ハウジング２０への固定の際にマンドレルで矯正されたものでは、焼結軸受１０の軸孔部表層が加工硬化しているので、切削加工でその部分を取り除いて軟質な部分を露出することにより、後続工程で軸孔をサイジングしたときにスプリングバックが起こり難く、マンドレルの寸法を高精度に転写することができる。切削加工面は平滑に仕上げられるが、加工面を拡大して観察すると切削加工面特有の細かなうねりが認められる。 (4) Cutting As shown by an arrow in FIG. 1B, the outer diameter of the bearing housing 20 is used as a reference surface, and the inner diameter of the sintered bearing 10 is cut with a cutting blade 30 to be finished to a predetermined dimension. Even if the dimensional accuracy of the bearing material varies greatly due to the assembly accuracy of the powder molding die, deformation due to sintering, etc., the degree of coaxiality with the outer diameter of the bearing housing 20 and the trueness of the processed surface can be reduced by cutting. Circularity and cylindricity can be finished with high accuracy. The accuracy can be about 1 μm. In the case where the sintered bearing 10 is sized or corrected with a mandrel when fixed to the bearing housing 20, the shaft hole surface layer of the sintered bearing 10 is work-hardened. By removing the soft part and exposing the soft part, when the shaft hole is sized in the subsequent process, the spring back hardly occurs and the dimensions of the mandrel can be transferred with high accuracy. The machined surface is finished smoothly, but when the machined surface is enlarged and observed, fine waviness unique to the machined surface is observed.

また、必要に応じて、焼結軸受の内径以外の焼結軸受の端面、面取り部、軸受ハウジング２０の段部や焼結軸受１０の端面との段差などが切削加工される。特に、軸受ハウジング２０の取り付けフランジ部を切削加工すると、その面と軸受内径面との直角精度をより確実なものとすることができる。   Further, if necessary, the end surface of the sintered bearing other than the inner diameter of the sintered bearing, the chamfered portion, the stepped portion of the bearing housing 20 and the end surface of the sintered bearing 10 are cut. In particular, when the mounting flange portion of the bearing housing 20 is cut, the perpendicularity between the surface and the bearing inner diameter surface can be made more reliable.

（５） 軸孔のサイジング
図１（ｃ）に示すように、高精度に切削加工された焼結軸受１０の内径を棒状のマンドレル４０を圧入してサイジングする。マンドレル４０は一方向に圧入貫通させる方法、一旦貫通させた後引き抜く方法とがあり、また、焼結軸受１０が固定された軸受ハウジング２０は、外周を開放した状態、ダイキャビティに装着して外周を拘束した状態でサイジングされる。サイジングの内径寸法の拡張は２〜１０μｍ程度とされるが、サイジング代はできるだけ少なく設定することが望ましい。サイジングによって軸孔面が平坦に仕上げられ、表面に露出する気孔を減少させることができる。 (5) Sizing of shaft hole As shown in FIG. 1C, the inner diameter of the sintered bearing 10 cut with high precision is sized by press-fitting a rod-shaped mandrel 40. The mandrel 40 has a method of press-fitting in one direction and a method of pulling out after once penetrating, and the bearing housing 20 to which the sintered bearing 10 is fixed is attached to the die cavity in a state where the outer periphery is opened. It is sized in a state where it is restrained. The expansion of the inner size of the sizing is about 2 to 10 μm, but it is desirable to set the sizing margin as small as possible. The axial hole surface is finished flat by sizing, and the pores exposed on the surface can be reduced.

本発明の製造方法では、図５に示したような軸心方向に延びる複数の動圧溝（油溝１７）を切削加工後の軸孔サイジングによって付与するのに好適である。切削加工により寸法精度が良好な軸孔に、突条４１を備えたマンドレル４０を押し込むと、軸孔に案内されて偏心がなくマンドレル４０の形状に忠実な軸孔を形成することができ、また、マンドレル４０の突条４１により押圧されて形成された動圧溝は表面が緻密化して気孔が少なくなり、高い動圧発生を生じやすい状態を形成する。造形するためのマンドレルは、棒状の外周に油溜まり溝およびクサビ状溝に対応する突条４１が軸方向形成され、マンドレル４０の先端部は切削加工された焼結軸受の内径寸法に嵌合する太さになっており、マンドレル４０の先端を焼結軸受１０の軸孔に差し込み、圧入して軸孔を貫通させることにより、油溝１７及びクサビ状溝を高精度に形成することができる。   The manufacturing method of the present invention is suitable for providing a plurality of dynamic pressure grooves (oil grooves 17) extending in the axial direction as shown in FIG. 5 by shaft hole sizing after cutting. When the mandrel 40 having the protrusions 41 is pushed into a shaft hole with good dimensional accuracy by cutting, a shaft hole that is guided by the shaft hole and has no eccentricity and is faithful to the shape of the mandrel 40 can be formed. The dynamic pressure grooves formed by being pressed by the protrusions 41 of the mandrel 40 have a dense surface and fewer pores, and form a state in which high dynamic pressure is likely to occur. In the mandrel for modeling, a protrusion 41 corresponding to the oil sump groove and the wedge-shaped groove is formed in the axial direction on the rod-shaped outer periphery, and the tip of the mandrel 40 is fitted to the inner diameter dimension of the cut sintered bearing. The oil groove 17 and the wedge-shaped groove can be formed with high accuracy by inserting the tip of the mandrel 40 into the shaft hole of the sintered bearing 10 and press-fitting it through the shaft hole.

また、前記の切削加工後に軸孔サイジングで動圧溝の全形を形成する方法に代えて、圧粉体で横断面が半円状で軸方向に延びる溝を形成しておき、その焼結体又はサイジング体を軸受ハウジングに固定し、軸孔の溝を残して軸孔面を切削加工したのち、前記の棒状の外周に油溜まり溝およびクサビ状溝に対応する突条４１が軸方向形成されたマンドレルを用いて、軸孔をサイジングしてもよい。この場合、油溝に対応するマンドレルの突条４１は焼結軸受の溝に嵌合して僅かに溝部をサイジングする程度とされ、クサビ状溝が造形される。クサビ状溝部はこのサイジングによって５〜８μｍ程度拡径される。   Further, instead of the method of forming the whole shape of the dynamic pressure groove by axial hole sizing after the above-mentioned cutting process, a groove having a semicircular cross section and extending in the axial direction is formed in the green compact, and the sintering is performed. After the body or sizing body is fixed to the bearing housing and the shaft hole surface is cut while leaving the shaft hole groove, the protrusion 41 corresponding to the oil reservoir groove and wedge-shaped groove is formed in the axial direction on the rod-shaped outer periphery. The axial hole may be sized using the mandrel made. In this case, the mandrel protrusion 41 corresponding to the oil groove is fitted to the groove of the sintered bearing so that the groove portion is slightly sized, and a wedge-shaped groove is formed. The wedge-shaped groove is enlarged by about 5 to 8 μm by this sizing.

（６）その他の付随工程及び組立
以上が本発明の製法の基本型であるが、軸受要素としての種々の従来技術を付随することができる。例えば、焼結軸受素材に油浸したり、切削加工やサイジングした後に洗浄したり、焼結軸受端面に工具を押しつけて封孔処理したり、軸受ハウジングにスラスト受け板を設置したり、磁性流体潤滑や磁性流体シール構造の場合では軸受ハウジングに永久磁石を装着したりする等である。 (6) Other incidental processes and assembly The above is the basic type of the manufacturing method of the present invention, but various conventional techniques as bearing elements can be associated. For example, oil immersion in sintered bearing material, cleaning after cutting or sizing, sealing with a tool pressed against the end face of the sintered bearing, installation of a thrust receiving plate on the bearing housing, magnetic fluid lubrication In the case of a magnetic fluid seal structure, a permanent magnet is mounted on the bearing housing.

次に、本発明の製造方法を実施例により説明する。
（実施例−１）
実施例は、図３に例示したような、軸受ハウジング２０内に２個の焼結軸受１２、１３が装着された軸受ユニットの製造である。 Next, the production method of the present invention will be described with reference to examples.
(Example-1)
The embodiment is a manufacture of a bearing unit in which two sintered bearings 12 and 13 are mounted in a bearing housing 20 as illustrated in FIG.

軸受ハウジング２０は、ステンレス鋼を切削加工し、所定の寸法形状に仕上げる。   The bearing housing 20 is cut into stainless steel and finished to a predetermined size and shape.

焼結軸受１２、１３の素材は単純な円筒形状で面取りされている。材料は青銅系焼結合金で、密度６．５Ｍｇ／ｍ3である。焼結軸受１２、１３の素材の内径寸法は、軸受ハウジング２０内に圧入したときの変形量、切削加工代、軸孔サイジング代が考慮される。 The material of the sintered bearings 12 and 13 is chamfered with a simple cylindrical shape. The material is a bronze-based sintered alloy with a density of 6.5 Mg / m 3 . Regarding the inner diameter dimensions of the sintered bearings 12 and 13, the amount of deformation, the cutting allowance, and the shaft hole sizing allowance when press-fitted into the bearing housing 20 are taken into consideration.

軸受ハウジング２０は治具に装着固定され、焼結軸受１２、１３のをマンドレルで案内して、マンドレルと嵌合しているパンチにより軸受ハウジング２０の孔内に圧入する。焼結軸受１２、１３の軸受は軸受ハウジング２０孔の両端に１個ずつ圧入固着される。   The bearing housing 20 is mounted and fixed to a jig, and the sintered bearings 12 and 13 are guided by a mandrel and are press-fitted into the hole of the bearing housing 20 by a punch fitted to the mandrel. One of the sintered bearings 12 and 13 is press-fitted and fixed to both ends of the bearing housing 20 hole.

旋盤を用い、軸受ハウジング２０の外周を基準面として固定し、焼結軸受１２、１３のの内径面を切削加工する。加工代は５〜５０μｍ程度とする。切り粉は除去する。   Using a lathe, the outer periphery of the bearing housing 20 is fixed as a reference surface, and the inner diameter surfaces of the sintered bearings 12 and 13 are cut. The machining allowance is about 5 to 50 μm. Remove chips.

次に、テーブル面とマンドレルの直角度が確保されたプレス機械を用い、マンドレルを焼結軸受の軸孔に圧入して抜き取りサイジングする。サイジング代は２〜５μｍである。   Next, the mandrel is press-fitted into the shaft hole of the sintered bearing and extracted and sized using a press machine in which the perpendicularity between the table surface and the mandrel is secured. The sizing allowance is 2-5 μm.

（実施例−２）
この実施例は、図５に例示したような、軸孔に軸方向に延びる動圧溝（油溝１７）を備えた焼結軸受１０が軸受ハウジング２０内に固着された軸受ユニットの製造である。 (Example-2)
This embodiment is a manufacture of a bearing unit in which a sintered bearing 10 having a dynamic pressure groove (oil groove 17) extending in the axial direction in an axial hole is fixed in a bearing housing 20 as illustrated in FIG. .

軸受ハウジング２０は、ステンレス鋼を切削加工し、所定の寸法形状に仕上げる。   The bearing housing 20 is cut into stainless steel and finished to a predetermined size and shape.

焼結軸受１０は材料が青銅系焼結合金で、密度６．８Ｍｇ／ｍ3である。焼結軸受１０の素材の軸孔には、圧粉成形時に形成された横断面が半円状で軸方向に延びる凹状（油溜め溝６８）が周方向等間隔に５カ所にある円筒形状で、端面縁は面取りされている。（油溝１７）の深さは０．１ｍｍである。焼結軸受１０の内径寸法は、切削加工代、軸孔サイジング代が考慮されている。また、焼結軸受１０の外形寸法は軸受ハウジング２０の孔寸法に対して１０μｍ以下の締まり嵌めになるように設定され、外周面に軸方向に延びる溝が形成されている。この外周溝は、後に接着剤が塗布される接着剤保持溝である。 The sintered bearing 10 is made of a bronze sintered alloy and has a density of 6.8 Mg / m 3 . The shaft hole of the material of the sintered bearing 10 has a cylindrical shape in which the cross section formed at the time of compacting is semicircular and has a concave shape (oil sump groove 68) extending in the axial direction at five equal intervals in the circumferential direction. The edge of the end face is chamfered. The depth of (oil groove 17) is 0.1 mm. As for the inner diameter dimension of the sintered bearing 10, a machining allowance and a shaft hole sizing allowance are considered. Further, the outer dimension of the sintered bearing 10 is set so as to be an interference fit of 10 μm or less with respect to the hole dimension of the bearing housing 20, and a groove extending in the axial direction is formed on the outer peripheral surface. This outer peripheral groove is an adhesive holding groove to which an adhesive is applied later.

軸受ハウジングは治具に装着固定され、焼結軸受素材の外周の溝に接着剤を塗布したのち、焼結軸受素材をマンドレルで案内して、マンドレルと嵌合しているパンチにより軸受ハウジング２０の孔内に圧入固着する。   The bearing housing is mounted and fixed to a jig, and after applying an adhesive to the outer peripheral groove of the sintered bearing material, the sintered bearing material is guided by a mandrel and the punch of the bearing housing 20 is fitted with the mandrel. Press fit into the hole.

接着剤が硬化した後、旋盤を用いて、軸受ハウジングの外周を基準面として固定し、焼結軸受１０の横断面が半円の溝（油溝１７）を残して内径面を切削加工する。加工代は１０〜５０μｍである。切削加工により軸孔は軸受ハウジングの外周と正確に同軸となり、加工面の露出気孔は減少する。付着している切り粉は除去される。   After the adhesive is cured, a lathe is used to fix the outer periphery of the bearing housing as a reference surface, and the inner surface is cut while leaving a groove (oil groove 17) having a semicircular cross section of the sintered bearing 10. The machining allowance is 10-50 μm. By cutting, the shaft hole is exactly coaxial with the outer periphery of the bearing housing, and the exposed pores on the machined surface are reduced. The adhering chips are removed.

次に、テーブル面とマンドレルの直角度が確保されたプレス機械を用い、マンドレルを焼結軸受の軸孔に圧入して抜き取りサイジングする。用いられるマンドレルは、棒状の外周に、焼結軸受素材の５カ所半円状溝（油溜め溝６８）に対応する横断面半円状の突条４１と、その突条４１から軸受面に延びるクサビ状溝６９を形成する突条４１とが軸方向形成されているものである。断面が半円状の突条４１は、焼結軸受素材の半円状溝を僅かにサイジングする程度であり、マンドレルと焼結軸受素材の位置合わせ手段になっている。軸受面のサイジング代は約２〜５μｍであり、クサビ状溝部の最も深い部分のサイジング代は５〜８μｍである。クサビ状溝部の露出気孔は更に減少し、動圧を生じやすくなっている。   Next, the mandrel is press-fitted into the shaft hole of the sintered bearing and extracted and sized using a press machine in which the perpendicularity between the table surface and the mandrel is secured. The mandrel used has a semicircular ridge 41 having a semicircular cross section corresponding to five semicircular grooves (oil sump groove 68) of the sintered bearing material on the rod-shaped outer periphery, and extends from the ridge 41 to the bearing surface. The ridges 41 forming the wedge-shaped grooves 69 are formed in the axial direction. The protrusion 41 having a semicircular cross-section has a size for slightly sizing the semicircular groove of the sintered bearing material, and is a means for aligning the mandrel and the sintered bearing material. The sizing margin of the bearing surface is about 2 to 5 μm, and the sizing margin of the deepest portion of the wedge-shaped groove is 5 to 8 μm. The exposed pores in the wedge-shaped groove portion are further reduced, and dynamic pressure is easily generated.

実施の形態は種々の組合せがあるがあり、前記実施例に示した方法には限定されない。   There are various combinations of the embodiments, and the method is not limited to the methods shown in the above examples.

本発明の製造方法によれば、図２に示した焼結軸受が傾いて圧入されたもの、図３のように二つの焼結軸受が偏心して圧入されたもの、図４のように二つの焼結軸受が圧入変形が異なったもの、図５のように軸受ハウジングに対して焼結軸受が偏心して圧入されたもの等においても、軸受ハウジングの外周（外径）を基準面とし高精度に切削加工して仕上げたのち、焼結軸受内径面をマンドレルで塑性変形させて平滑にしたり緻密な面の動圧溝を形成するものであるから、偏心が極めて小さく寸法精度が良好で大量生産によるばらつきが少ないものとなり、モータ等の軸受用として好ましいものである。   According to the manufacturing method of the present invention, the sintered bearing shown in FIG. 2 is tilted and press-fitted, two sintered bearings are eccentrically pressed as shown in FIG. 3, and two sintered bearings are shown in FIG. Sintered bearings with different press-fit deformations, and those with a sintered bearing eccentrically inserted with respect to the bearing housing as shown in FIG. 5, etc., have a high precision with the outer circumference (outer diameter) of the bearing housing as the reference plane. After machining and finishing, the inner diameter surface of the sintered bearing is plastically deformed with a mandrel to make it smooth or form a dynamic pressure groove with a dense surface. The variation is small, which is preferable for bearings such as motors.

本発明方法によって製造された軸受ユニットと、従来の方法で製造された軸受ユニットの寸法精度を比較すると、軸受の真円度は、従来法によれば３μｍ、本発明の方法によれば１μｍであった。回転軸の直角度は、従来法によれば最小値０．６μｍから最大値６．５μｍであるのに比べ、本発明の方法によれば最小値０．４μｍから最大値２．１μｍ程度であり、ばらつきが１／３以下であった。また、ブラシレスモータに組立てて運転したときの軸の回転振れの最大値が、本発明の方法で製造されたものは従来の方法によるものの約１／１０であった。このように、モータの品質を格段に向上できることが判る。   Comparing the dimensional accuracy of the bearing unit manufactured by the method of the present invention and the bearing unit manufactured by the conventional method, the roundness of the bearing is 3 μm according to the conventional method and 1 μm according to the method of the present invention. there were. According to the method of the present invention, the squareness of the rotating shaft is about 0.4 μm to 2.1 μm, compared with the minimum value of 0.6 μm to the maximum value of 6.5 μm according to the conventional method. The variation was 1/3 or less. Moreover, the maximum value of the rotational runout of the shaft when assembled and operated in a brushless motor was about 1/10 that of the conventional method manufactured by the method of the present invention. Thus, it can be seen that the quality of the motor can be remarkably improved.

本発明の工程を示す模式図である。It is a schematic diagram which shows the process of this invention. 本発明の工程を示す模式図である。It is a schematic diagram which shows the process of this invention. 本発明の工程を示す模式図である。It is a schematic diagram which shows the process of this invention. 軸受ハウジングに圧入した焼結軸受が傾いている状態を示す断面図である。It is sectional drawing which shows the state which the sintered bearing press-fit in the bearing housing inclines. 軸受ハウジングに圧入した２個の焼結軸受が偏心している状態を示す断面図である。It is sectional drawing which shows the state from which the two sintered bearings press-fit in the bearing housing are eccentric. 軸受ハウジングに圧入した２個の焼結軸受が内径寸法が異なっている状態を示す断面図である。It is sectional drawing which shows the state from which the two sintered bearings press-fit in the bearing housing differ in an internal diameter dimension. 軸受ハウジングに圧入した焼結軸受の軸孔が偏心しており、動圧溝が形成されている状態を示す断面図である。It is sectional drawing which shows the state in which the axial hole of the sintered bearing press-fit in the bearing housing is eccentric, and the dynamic pressure groove is formed. 軸受ハウジングに圧入した焼結軸受の塑性変形が部分的に異なっている状態を示す断面図である。It is sectional drawing which shows the state from which the plastic deformation of the sintered bearing press-fit in the bearing housing is partially different.

符号の説明Explanation of symbols

１０，１２，１３，１４，１５ 焼結軸受（素材）
１１、１１ａ、２１ 軸心
１６ 矢印
１７、１８ 油溝
１９ 薄肉部
２０ 軸受ハウジング
３０ 切削刃物
４０ マンドレル
４１ 突条
４２ 矢印 10, 12, 13, 14, 15 Sintered bearing (material)
11, 11a, 21 Axes 16 Arrows 17, 18 Oil groove 19 Thin part 20 Bearing housing 30 Cutting blade 40 Mandrel 41 Projection 42 Arrow

Claims (3)

金属原料粉を所定の軸受形状に成形及び焼結した焼結軸受素材を、軸受ハウジング内に装着固定し、軸受ハウジングの外周面を基準面としてこれに倣って焼結軸受素材の内周面を切削加工し、該切削加工された焼結軸受素材の内周面をサイジングすることを特徴とする滑り軸受の製造方法。   A sintered bearing material in which metal raw material powder is molded and sintered into a predetermined bearing shape is mounted and fixed in the bearing housing, and the outer peripheral surface of the bearing housing is used as a reference surface to follow the inner peripheral surface of the sintered bearing material. A method of manufacturing a sliding bearing, comprising cutting and sizing the inner peripheral surface of the sintered bearing material that has been cut. 前記内周面をサイジングする際に、軸方向に延びる凸条を外周に複数備えたマンドレルを用い、軸受内周面にサイジングにより軸方向に延びる複数の動圧溝を形成することを特徴とする請求項１記載の滑り軸受の製造方法。   When sizing the inner peripheral surface, a mandrel having a plurality of protruding ridges extending in the axial direction on the outer periphery is used, and a plurality of dynamic pressure grooves extending in the axial direction are formed on the inner peripheral surface of the bearing by sizing. The manufacturing method of the sliding bearing of Claim 1. 前記焼結軸受素材の内周面を切削加工して切削面の気孔を減少させ、切削加工された焼結軸受素材の内周面をサイジングして軸受内周面の気孔をさらに減少させることを特徴とする請求項１又は２記載の滑り軸受の製造方法。   Cutting the inner peripheral surface of the sintered bearing material to reduce pores on the cut surface, and sizing the inner peripheral surface of the sintered bearing material that has been cut to further reduce the pores on the inner peripheral surface of the bearing. The method for manufacturing a plain bearing according to claim 1 or 2, characterized in that:
JP2003382848A 2003-11-12 2003-11-12 Sliding bearing manufacturing method Pending JP2005155655A (en)

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007051708A (en) * 2005-08-18 2007-03-01 Hitachi Powdered Metals Co Ltd Fluid dynamic bearing unit and spindle motor using the same
JP2007192372A (en) * 2006-01-20 2007-08-02 Ntn Corp Fluid bearing device and its manufacturing method
JP2008142885A (en) * 2006-12-05 2008-06-26 Sandvik Mining & Construction Oy Method for attaching tool of breaking device by bearing and breaking device
JP2008163955A (en) * 2006-12-26 2008-07-17 Toribotex Co Ltd Sliding bearing structure manufacturing method
US9080604B2 (en) 2011-06-09 2015-07-14 Federal-Mogul Wiesbaden Gmbh Plain bearing shell with slide face surface geometry which is profiled in the axial direction

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007051708A (en) * 2005-08-18 2007-03-01 Hitachi Powdered Metals Co Ltd Fluid dynamic bearing unit and spindle motor using the same
JP4587220B2 (en) * 2005-08-18 2010-11-24 日立粉末冶金株式会社 Hydrodynamic bearing unit and spindle motor using the same
JP2007192372A (en) * 2006-01-20 2007-08-02 Ntn Corp Fluid bearing device and its manufacturing method
JP4685641B2 (en) * 2006-01-20 2011-05-18 Ｎｔｎ株式会社 Hydrodynamic bearing device and manufacturing method thereof
JP2008142885A (en) * 2006-12-05 2008-06-26 Sandvik Mining & Construction Oy Method for attaching tool of breaking device by bearing and breaking device
US8550180B2 (en) 2006-12-05 2013-10-08 Sandvik Mining And Construction Oy Bearing of a breaking device tool
JP2008163955A (en) * 2006-12-26 2008-07-17 Toribotex Co Ltd Sliding bearing structure manufacturing method
US9080604B2 (en) 2011-06-09 2015-07-14 Federal-Mogul Wiesbaden Gmbh Plain bearing shell with slide face surface geometry which is profiled in the axial direction

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