JP2008248288A - Sintered metal component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the sliding performance of a sintered metal component by increasing the feeding performance of lubricating oil in the sliding face of the sintered metal component and further polishing the sliding face without leaving foreign matter. <P>SOLUTION: An inner ring used for a torque limiter is produced through: a stage (a) where raw material powder is subjected to powder compaction; a stage (b) where the powder-compacted body is sintered; a stage (c) where the sintered compact is subjected to sizing; a stage (d) where the sintered compact is subjected to heat treatment; a stage (e) where the sintered compact is subjected to barrel polishing by mutual rubbing; and a stage (f) where the sintered compact is impregnated with lubricating oil. In the barrel polishing stage by mutual rubbing (e), a plurality of sintered compacts are charged to the inside of a barrel type vessel, and the barrel type vessel is rotated or reciprocated along the rotary shaft, thus a mutual polishing action is applied to the sintered compacts in the vessel, and the surfaces of the sintered compacts including sliding faces are polished. Simultaneously, the sintered compacts are mutually collided each other, so as to form recessed parts on the sliding faces of the sintered compacts as deformed marks caused by the collision. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

本発明は、摺動面を有する焼結金属部品、特にその外面側に摺動面を有する焼結金属部品に関する。   The present invention relates to a sintered metal part having a sliding surface, and more particularly to a sintered metal part having a sliding surface on the outer surface side thereof.

従来、各種機械部品、特に軸受部や動力伝達部など他の機械要素との間で摺動を伴う部分に使用される機械部品に、焼結金属で形成されその内部空孔に潤滑油等を含浸させた焼結金属部品が好適に用いられている。   Conventionally, various machine parts, especially machine parts used for parts that slide with other machine elements such as bearings and power transmission parts, are formed of sintered metal and lubricated in the internal holes. Impregnated sintered metal parts are preferably used.

例えば、トルクリミッタの内輪を焼結金属で形成し、この内輪の内部空孔に潤滑油を含浸させたものが知られている（例えば、特許文献１を参照）。   For example, it is known that an inner ring of a torque limiter is formed of a sintered metal and an internal hole of the inner ring is impregnated with lubricating oil (see, for example, Patent Document 1).

また、この内輪への潤滑油の含浸作業を低温下で行うことにより、この内輪を組み込んだトルクリミッタの使用時、潤滑油の内部への引き込みを抑えて摺動面での潤滑性を高めたものが提案されている（例えば、特許文献２を参照）。   In addition, by performing the impregnation operation of the lubricating oil into the inner ring at a low temperature, when using a torque limiter incorporating this inner ring, the lubricating oil on the sliding surface is improved by suppressing the pulling of the lubricating oil into the inner ring. Have been proposed (see, for example, Patent Document 2).

また、トルクリミッタは、その内輪と外輪、あるいは外輪と連結したコイルばね等との間でトルク伝達と相対摺動とを繰り返すものであるから、その内輪には、長期使用に耐え得るよう高い耐久性（耐摩耗性）が要求される。かかる耐久性を満足するため、例えば特開２００２−３７２０６９号公報（特許文献３）には、カラー（内輪）にバレル研磨を施すことで、摺動面となる外周面の表面粗さを所定範囲に調整する方法が提案されている。   The torque limiter repeats torque transmission and relative sliding between the inner ring and the outer ring, or a coil spring connected to the outer ring, so that the inner ring has high durability so that it can withstand long-term use. (Wear resistance) is required. In order to satisfy such durability, for example, in Japanese Patent Application Laid-Open No. 2002-372069 (Patent Document 3), the collar (inner ring) is barrel-polished so that the surface roughness of the outer peripheral surface serving as the sliding surface is within a predetermined range. A method of adjusting to is proposed.

また、耐久性向上のため、焼結体に熱処理を施すことで摺動面の硬度向上を図る手段が提案されているが、この場合にも、熱処理時に生じたスケール等の異物を除去する目的でバレル研磨を行うようにしている（何れも、特許文献２を参照）。
特開平８−２７０６７３号公報 特開２００４−２９２８５４号公報 特開２００２−３７２０６９号公報 In order to improve the durability, means for improving the hardness of the sliding surface by applying a heat treatment to the sintered body has been proposed. In this case as well, the purpose of removing foreign matters such as scales generated during the heat treatment is proposed. In this case, barrel polishing is performed (see Patent Document 2 for both).
JP-A-8-270673 JP 2004-292854 A JP 2002-372069 A

ところで、潤滑油の焼結金属軸受への含浸作業は、通常、焼結金属軸受を減圧環境下で潤滑油に浸漬して行われる（いわゆる真空含浸）。この際、例えば潤滑油を加熱し、粘性抵抗を下げた状態で含浸作業を行えば、潤滑油が焼結金属軸受の内部空孔に入り込み易くなる。しかしながら、この方法による含浸を行った製品においては、初期の摺動時に軸受面に潤滑油が存在せず、潤滑油による潤滑作用が十分に得られない場合が考えられる。   By the way, the impregnation of the sintered oil into the sintered metal bearing is usually performed by immersing the sintered metal bearing in the lubricant under a reduced pressure environment (so-called vacuum impregnation). At this time, for example, if the impregnation operation is performed in a state where the lubricating oil is heated and the viscosity resistance is lowered, the lubricating oil easily enters the internal holes of the sintered metal bearing. However, in a product that has been impregnated by this method, there may be a case where there is no lubricating oil on the bearing surface during the initial sliding, and the lubricating action by the lubricating oil cannot be sufficiently obtained.

すなわち、潤滑油は、通常、金属の数百倍もの繊膨張係数を有するため、加熱した状態の潤滑油を含浸した後、製品が使用温度（例えば常温）まで冷却されることで、収縮比の大きい潤滑油が焼結軸受内に引き込まれ、軸受面上に潤滑油が残らない場合が起こり得る。これでは、軸と軸受とが接触摺動することになり、十分な潤滑効果が得られないことから、摩擦の増大を招き、軸受の摩耗をはじめ、異音や振動の発生が懸念される。   That is, since the lubricating oil usually has a fiber expansion coefficient several hundred times that of a metal, after impregnating the heated lubricating oil, the product is cooled to the operating temperature (for example, room temperature), so that the shrinkage ratio is reduced. Large lubricants can be drawn into the sintered bearing, leaving no lubricant on the bearing surface. In this case, the shaft and the bearing are in sliding contact with each other, and a sufficient lubrication effect cannot be obtained. This causes an increase in friction, and there is a concern about generation of abnormal noise and vibrations, including wear of the bearing.

特許文献２には、内輪への潤滑油の含浸作業を低温下で行うことにより、この内輪を組み込んだトルクリミッタの使用時、潤滑油の内部への引き込みを抑制する旨が開示されているが、油の引き込みが生じることには違いなく、かかる手段で摺動面での潤滑油不足が解消されるとは言い難い。   Patent Document 2 discloses that the operation of impregnating the lubricating oil into the inner ring is performed at a low temperature, thereby suppressing the pulling of the lubricating oil into the interior when the torque limiter incorporating the inner ring is used. The oil pull-in must occur, and it is difficult to say that such a means can solve the shortage of lubricating oil on the sliding surface.

また、特許文献２や３に開示のバレル研磨を行う際には、研磨対象となる焼結体と共にメディア等の研磨材を投入して行うのが一般的である。しかしながら、焼結体には多数の表面開孔が存在するため、上述の如くバレル研磨処理を行うと、研磨材として投入したメディアあるいはその一部が、焼結体の表面開孔に突き刺さる場合がある。突き刺さったメディアは、バレル研磨後に洗浄処理を施した場合であっても容易には除去できず、完成品の表面に突き刺さったままの状態で残る恐れがある。特に、摺動面となる領域に突き刺さったままのメディアがあると、相手部材を傷付けることになり、摺動摩耗の増大、ひいては使用寿命の低下を招く恐れがあり好ましくない。上述の問題は、トルクリミッタ用の内輪以外の摺動部品を焼結金属で形成する場合にも同様に起こり得る。   In addition, when performing barrel polishing disclosed in Patent Documents 2 and 3, it is common to perform by putting an abrasive such as media together with a sintered body to be polished. However, since the sintered body has a large number of surface openings, when the barrel polishing treatment is performed as described above, the medium or part of the medium introduced as an abrasive may pierce the surface openings of the sintered body. is there. The pierced media cannot be easily removed even when the cleaning process is performed after barrel polishing, and may remain in the state of being pierced on the surface of the finished product. In particular, if there is a medium that is stuck in the area that becomes the sliding surface, the mating member is damaged, which may increase sliding wear and eventually reduce the service life. The above-mentioned problem can occur in the same manner when a sliding part other than the inner ring for the torque limiter is formed of sintered metal.

以上の事情に鑑み、本発明では、焼結金属部品の摺動面における潤滑油の供給性能を高めると共に、異物を残すことなく摺動面の研磨を行うことで、摺動性能の改善を図ることを技術的課題とする。   In view of the above circumstances, in the present invention, the lubrication oil supply performance on the sliding surface of the sintered metal component is enhanced, and the sliding performance is improved by polishing the sliding surface without leaving foreign matter. This is a technical issue.

前記課題を解決するため、本発明は、金属粉末を圧粉成形し、焼結して得られる多孔質の焼結体で、その内部空孔に潤滑流体が含浸されると共に、他部材との摺動面を有する焼結金属部品の製造方法であって、複数の焼結体を容器に投入し、容器の運動により、複数の焼結体を相互に研磨材として作用させ摺動面を研磨すると共に、複数の焼結体を相互に衝突させ摺動面に衝突による凹部を形成する工程と、焼結体の内部空孔および凹部に潤滑流体を供給する工程とを少なくとも備える焼結金属部品の製造方法を提供する。   In order to solve the above-mentioned problems, the present invention is a porous sintered body obtained by compacting and sintering a metal powder, the internal pores of which are impregnated with a lubricating fluid, and A method of manufacturing a sintered metal part having a sliding surface, in which a plurality of sintered bodies are put into a container, and the plurality of sintered bodies act as abrasives by the movement of the container to polish the sliding surface. A sintered metal part comprising at least a step of causing a plurality of sintered bodies to collide with each other to form a concave portion due to the collision on the sliding surface, and a step of supplying a lubricating fluid to the internal pores and the concave portion of the sintered body A manufacturing method is provided.

このように、本発明では、複数の焼結体を容器に投入し、この容器の運動により、焼結体相互に研磨作用をもたせ、この研磨作用で摺動面を研磨するようにした。これにより、、メディア等の研磨材を別途投入することなく、焼結体の外面側に設けた摺動面の研磨を行うことができる。そのため、研磨後、メディア等の異物が焼結体の表面開孔に残存するのを可及的に防いで、良好な面性状を有する摺動面を得ることができる。   Thus, in the present invention, a plurality of sintered bodies are put into a container, and the movement of the container gives the sintered bodies a polishing action, and the sliding surface is polished by this polishing action. Thereby, the sliding surface provided on the outer surface side of the sintered body can be polished without separately supplying an abrasive such as media. Therefore, it is possible to prevent as much as possible foreign matters such as media from remaining in the surface openings of the sintered body after polishing, and to obtain a sliding surface having good surface properties.

また、本発明では、同一容器内で複数の焼結体を相互に衝突させ、当該焼結体の表面に、衝突による凹部を形成すると共に、この凹部に、研磨工程後の潤滑流体供給工程において潤滑流体を供給するようにした。これにより、摺動面上の凹部に保持された潤滑流体により、摺動面上に容易かつ早急に潤滑油を供給することができ、例えば摺動初期における潤滑油不足を解消することができる。特に、上述の研磨工程で形成された凹部であれば、表面開孔と比べて大容積の油溜りとして機能するため、潤滑油の供給性能を一層高めることができる。また、この凹部は相互衝突により形成されるものであるから、当該凹部の周囲にバリや返りなどの突起を生じる可能性は低い。そのため、研磨された摺動面の平滑性を損なわせることなく、他部材との間で良好な摺動状態を得ることができる。   Further, in the present invention, a plurality of sintered bodies collide with each other in the same container, and a concave portion due to the collision is formed on the surface of the sintered body, and in this lubricating fluid supply step after the polishing step, the concave portion is formed. A lubricating fluid was supplied. Thus, the lubricating oil held in the recess on the sliding surface can supply the lubricating oil easily and quickly on the sliding surface, and for example, the lack of lubricating oil in the initial sliding can be solved. In particular, if the recess is formed by the above-described polishing step, it functions as a large-volume oil reservoir as compared with the surface opening, so that the lubricating oil supply performance can be further enhanced. Moreover, since this recessed part is formed by mutual collision, possibility that protrusions, such as a burr | flash and a return, will be produced around the said recessed part is low. Therefore, a favorable sliding state can be obtained with other members without impairing the smoothness of the polished sliding surface.

その一方で、潤滑油が滲み出る摺動面は他部材との摺動を必然的に伴うものであるから、他部材との摺動摩耗を低減し、耐久性のさらなる向上を図ることが望ましい。かかる事情に鑑み、本発明では、上述の相互研磨工程の前に摺動面をサイジングする工程をさらに設けることとした。   On the other hand, since the sliding surface from which the lubricating oil oozes is inevitably accompanied by sliding with other members, it is desirable to reduce sliding wear with other members and further improve durability. . In view of such circumstances, the present invention further includes a step of sizing the sliding surface before the above-described mutual polishing step.

このように、摺動面をサイジングすることで、当該摺動面を高精度に仕上げてその寸法精度や面精度を高めることができる。また、予めサイジングを施した焼結体に対して上述の研磨処理を施すようにすれば、上記研磨時、焼結体が相互に衝突して形成される凹部をサイジングにより消滅させてしまう恐れもないため、かかる順序でサイジングと研磨とを実施するのが好ましい。   Thus, by sizing the sliding surface, it is possible to finish the sliding surface with high accuracy and to increase its dimensional accuracy and surface accuracy. Further, if the above-described polishing treatment is performed on a sintered body that has been sized in advance, there is a possibility that the concave portions formed by the collision of the sintered bodies with each other may be eliminated by sizing during the polishing. Therefore, it is preferable to perform sizing and polishing in this order.

また、特に摺動面の硬度向上が必要となる場合には、サイジング工程の後でかつ相互研磨工程の前に、焼結体に対して熱処理を施し、摺動面の硬度向上を図る熱処理工程をさらに設けることもできる。サイジングの後に熱処理を行うのであれば、過度な荷重を必要とすることなくサイジングを実施することができ、サイジングの加工精度も高い。また、相互研磨工程の前に摺動面の硬度向上のための熱処理を実施しておけば、後の相互研磨工程で、熱処理により表面に生じるスケール等の異物を除去することができる。   In addition, particularly when it is necessary to improve the hardness of the sliding surface, a heat treatment process is performed after the sizing process and before the mutual polishing process to heat-treat the sintered body to improve the hardness of the sliding surface. Can also be provided. If heat treatment is performed after sizing, sizing can be performed without requiring an excessive load, and the processing accuracy of sizing is high. Further, if heat treatment for improving the hardness of the sliding surface is performed before the mutual polishing step, foreign matters such as scales generated on the surface by the heat treatment can be removed in the subsequent mutual polishing step.

上述の方法で製造された焼結金属部品は、例えば筒状をなし外周に摺動面を有するもので、その外側に配した他部材としてのコイルばねから締付け力を受ける向きに回転する際、コイルばねとの間でトルク伝達を行い、伝達トルクが所定量を超えた場合、摺動面とコイルばねとの間で相対摺動を行う、トルクリミッタの内輪として好適に提供することができる。あるいは、この内輪を備えたトルクリミッタとして好適に提供することができる。   The sintered metal part manufactured by the above method has, for example, a cylindrical shape and a sliding surface on the outer periphery, and when rotating in a direction to receive a tightening force from a coil spring as another member arranged on the outer side, Torque is transmitted to and from the coil spring, and when the transmitted torque exceeds a predetermined amount, it can be suitably provided as an inner ring of a torque limiter that performs relative sliding between the sliding surface and the coil spring. Or it can provide suitably as a torque limiter provided with this inner ring.

以上より、本発明によれば、焼結金属部品の摺動面における潤滑油の供給性能を高めると共に、異物を残すことなく摺動面の研磨を行うことで、摺動性能の改善を図ることができる。   As described above, according to the present invention, the lubrication oil supply performance on the sliding surface of the sintered metal component is enhanced, and the sliding performance is improved by polishing the sliding surface without leaving foreign matter. Can do.

以下、本発明の一実施形態を図１〜図６に基づいて説明する。   Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

図１は、本発明に係る焼結金属部品の製造方法の一例を示す工程の流れ図である。この製造方法は、例えば筒状をなし、その外周にコイルばねとの摺動面を有するトルクリミッタ用の内輪（図７中、符号１１で示す部品）を製造するためのものであり、原料粉末を圧粉成形する工程（ａ）、圧粉成形体を焼結する工程（ｂ）、焼結体にサイジングを施す工程（ｃ）、焼結体に熱処理を施す工程（ｄ）、焼結体に共ずりバレル研磨を施す工程（ｅ）、焼結体に潤滑油を含浸させる工程（ｆ）とを含む。以下、各工程を時系列順に説明する。なお、ここでは、含油工程の前に実施する「共ずりバレル工程」が、本発明における「相互研磨工程」に相当する。   FIG. 1 is a process flow chart showing an example of a method for producing a sintered metal part according to the present invention. This manufacturing method is, for example, for manufacturing an inner ring for a torque limiter (part indicated by reference numeral 11 in FIG. 7) having a cylindrical shape and having a sliding surface with a coil spring on the outer periphery. A step of compacting (a), a step of sintering a compact (b), a step of sizing the sintered compact (c), a step of applying heat treatment to the sintered compact (d), and a sintered compact The step (e) of performing barrel polishing and the step (f) of impregnating the sintered body with a lubricating oil. Hereinafter, each process will be described in chronological order. Here, the “co-axial barrel process” performed before the oil impregnation process corresponds to the “mutual polishing process” in the present invention.

（ａ）圧粉成形工程
まず、原料となる金属粉末を成形金型内部に充填し、これを圧縮成形することで完成品（ここでは円筒状をなすトルクリミッタの内輪１１）に近い形状の圧粉成形体を得る。なお、原料には、例えばＦｅあるいはＦｅ系合金の金属粉末を主成分とするものが用いられるが、ＣｕあるいはＣｕ系合金の金属粉末など他の金属粉末を原料に用いることもでき、これら複数種の金属粉末を混合したものを原料として用いることもできる。また、必要に応じて、Ｓｎ等のバインダ、黒鉛や二硫化モリブデン等の粉末状固体潤滑剤のうち一種以上を原料に添加したものを用いても構わない。 (A) Compacting process First, a metal powder as a raw material is filled into a molding die, and this is compression-molded to form a pressure close to that of a finished product (here, a cylindrical inner ring 11 of a torque limiter). A powder compact is obtained. As the raw material, for example, a material mainly composed of Fe or Fe-based alloy metal powder is used, but other metal powders such as Cu or Cu-based alloy metal powder can be used as the raw material. A mixture of these metal powders can also be used as a raw material. Moreover, you may use what added 1 or more types of powdery solid lubricants, such as binders, such as Sn, graphite, and molybdenum disulfide, to the raw material as needed.

（ｂ）焼結工程
上記工程（ａ）で得られた圧粉成形体を、原料となる金属粉末の焼結温度まで加熱することで焼結し、焼結体を得る。図２は、原料となる金属粉末２を互いに焼結結合してなる焼結体１の、表層部の拡大断面図を示す。同図より、焼結体１には多数の内部空孔３が存在すると共に、その表面に多数の表面開孔４が存在している。なお、使用する金属粉末の種類によっては、焼結による浸炭作用を避けるため、かかる焼結作業を非浸炭雰囲気下で行うことも可能である。 (B) Sintering process The compacting body obtained by the said process (a) is sintered by heating to the sintering temperature of the metal powder used as a raw material, and a sintered compact is obtained. FIG. 2 shows an enlarged cross-sectional view of a surface layer portion of a sintered body 1 obtained by sintering and bonding metal powders 2 as raw materials. From the figure, the sintered body 1 has a large number of internal holes 3 and a large number of surface openings 4 on the surface thereof. Depending on the type of metal powder used, the sintering operation can be performed in a non-carburizing atmosphere in order to avoid the carburizing action due to sintering.

（ｃ）サイジング工程
上記工程（ｂ）で得られた焼結体に対し、適当な金型を用いて圧迫力を付与することで、焼結体を所定形状に整形すると共に、その寸法を所定の精度に仕上げる。図３は、サイジング後の焼結体１における表層部の拡大断面図を示している。同図より、焼結体１の表面（外周面）がサイジングにより平滑化され、これにより外周面に摺動面５が形成されている。また、サイジングを受けて生じた変形は内部空孔３に吸収されると共に、その表面開孔４を埋める向きに生じる。 (C) Sizing step By applying a pressing force to the sintered body obtained in the step (b) using an appropriate mold, the sintered body is shaped into a predetermined shape, and the dimensions thereof are predetermined. Finish with precision. FIG. 3 shows an enlarged cross-sectional view of the surface layer portion of the sintered body 1 after sizing. From the figure, the surface (outer peripheral surface) of the sintered body 1 is smoothed by sizing, whereby the sliding surface 5 is formed on the outer peripheral surface. Further, the deformation caused by the sizing is absorbed in the internal holes 3 and is caused to fill the surface openings 4.

（ｄ）熱処理工程
上記工程（ｃ）で得られた焼結体に対し、適当な熱処理を施し、焼結体のうち摺動面となる領域の硬度を向上させる。この実施形態では、焼結体１に対して浸炭焼き入れを行うことで、摺動面５を含む焼結体１表層部の硬度を向上させるようにしている。 (D) Heat treatment process Appropriate heat treatment is performed on the sintered body obtained in the above step (c) to improve the hardness of the area to be a sliding surface of the sintered body. In this embodiment, the hardness of the surface layer portion of the sintered body 1 including the sliding surface 5 is improved by carburizing and quenching the sintered body 1.

（ｅ）共ずりバレル工程
熱処理工程（ｄ）を経た焼結体１に対して、共ずりバレル研磨を施す。具体的には、図示は省略するが、複数の焼結体１をバレル型容器内に投入し、このバレル型容器を回転あるいは回転軸に沿って往復運動等させることにより、容器内の焼結体１に相互の研磨作用を付与し、摺動面５を含む焼結体１表面を研磨する。これにより、先の熱処理時に焼結体１表面に形成されたスケールなどの不純物を除去する。また、焼結体１同士の相互の衝突（の繰り返し）により、焼結体１の表面に、衝突による変形痕としての凹部が形成される。なお、バレル型容器は、回転運動させる際、その回転軸に沿った往復運動など他の運動を伴うものであってもよい。また、バレル型容器内には、水など実質的に研磨作用を有しない媒体を複数の焼結体１と共に投入することも可能である。 (E) Joint shear barrel process The joint body barrel grinding | polishing is given with respect to the sintered compact 1 which passed through the heat processing process (d). Specifically, although not shown in the drawing, a plurality of sintered bodies 1 are put into a barrel type container, and the barrel type container is rotated or reciprocated along the rotation axis to sinter the container. A mutual polishing action is imparted to the body 1 to polish the surface of the sintered body 1 including the sliding surface 5. Thereby, impurities such as scale formed on the surface of the sintered body 1 during the previous heat treatment are removed. Further, due to mutual collision (repetition) of the sintered bodies 1, a concave portion as a deformation mark due to the collision is formed on the surface of the sintered body 1. The barrel-type container may be accompanied by other movements such as a reciprocating movement along the rotation axis when rotating. In addition, a medium having substantially no polishing action such as water can be put into the barrel type container together with the plurality of sintered bodies 1.

図４は、共ずりバレル後の焼結体１の摺動面周辺を拡大した断面図を示す。この図に示すように、摺動面５の一部領域には、焼結体相互に衝突することによる凹部６が形成されている。ここで、摺動面５に形成される凹部６は焼結体１相互の衝突により形成されたものであるから、同じく摺動面５上に存在する表面開孔４に比べて非常に大きい寸法（容積）を有する。   FIG. 4 shows an enlarged cross-sectional view of the periphery of the sliding surface of the sintered body 1 after the common barrel. As shown in this figure, a recessed portion 6 is formed in a partial region of the sliding surface 5 by colliding with the sintered bodies. Here, since the recess 6 formed in the sliding surface 5 is formed by the collision between the sintered bodies 1, the dimension is much larger than the surface opening 4 that is also present on the sliding surface 5. (Volume).

（ｆ）含油工程
上記（ａ）〜（ｅ）の工程を経た焼結体１に潤滑油を含浸させる。具体的には、所定の減圧環境下で、潤滑油で満たした潤滑油浴中に焼結体１を一定時間浸漬させることで、内部空孔３に潤滑油を含浸させると共に、焼結体１の表面（摺動面５）に形成された凹部６にも潤滑油を供給する。図５は、含油後の焼結体１の摺動面周辺を拡大した断面図を示す。同図に示すように、含油後の状態では、表面開孔４や凹部６が潤滑油７で満たされると共に、摺動面５も潤滑油７で覆われた状態、言い換えると、焼結体１の表面が潤滑油の膜で覆われた状態となっている。なお、この際、潤滑油の内部空孔３への含浸を確実かつ短時間で行うため、潤滑油を加熱した状態で含浸作業を行うこともできる。あるいは、使用時の潤滑油の内部への引き込みを考慮して、潤滑油の温度を使用温度に近づけた状態で上述の含浸作業を行うこともできる。 (F) Oil impregnation process The sintered compact 1 which passed through the process of said (a)-(e) is impregnated with lubricating oil. Specifically, the sintered body 1 is impregnated with the lubricating oil in the internal pores 3 by immersing the sintered body 1 in a lubricating oil bath filled with the lubricating oil for a predetermined time under a predetermined reduced pressure environment. Lubricating oil is also supplied to the recess 6 formed on the surface (sliding surface 5). FIG. 5 shows an enlarged cross-sectional view of the periphery of the sliding surface of the sintered body 1 after oil impregnation. As shown in the figure, in a state after oil impregnation, the surface opening 4 and the recess 6 are filled with the lubricating oil 7 and the sliding surface 5 is also covered with the lubricating oil 7, in other words, the sintered body 1 The surface of is covered with a lubricating oil film. At this time, since the impregnation of the lubricating oil into the internal holes 3 is performed reliably and in a short time, the impregnation operation can be performed in a state where the lubricating oil is heated. Or the above-mentioned impregnation operation | work can also be performed in the state which brought the temperature of the lubricating oil close to the operating temperature in consideration of the drawing of the lubricating oil into the interior during use.

そして、含浸作業後、適当な油除去装置（例えば遠心分離機）を用いて油切り作業を行う。これにより、内部空孔３に含浸させた潤滑油は保持されると共に、表面に付着した余分な潤滑油が除去され、焼結金属部品、ここではトルクリミッタ用の内輪１１が完成する。なお、この油切り作業においては、少なくとも凹部６に潤滑油７が保持される程度に油切りを行うことが肝要である。   And after an impregnation operation | work, an oil removal operation | work is performed using a suitable oil removal apparatus (for example, centrifuge). As a result, the lubricating oil impregnated in the internal air holes 3 is held and excess lubricating oil adhering to the surface is removed, and the sintered metal part, here, the inner ring 11 for the torque limiter is completed. In this oil draining operation, it is important to perform the oil draining to such an extent that the lubricating oil 7 is retained in at least the recess 6.

このように、共ずりバレル研磨工程（ｅ）において、バレル型容器内に複数の焼結体１を投入し、この容器に適当な運動を与えることで、容器内の焼結体１間で相互に摺動し、一の焼結体１が他の焼結体１に対して研磨作用を発揮する。これにより、メディア等の研磨材を別途投入することなく焼結体１の外周面に設けた摺動面５の研磨を行うことができ、研磨後の焼結体１表面に何らかの物体が表面開孔４に突き刺さる事態を防止することができる。   As described above, in the joint barrel polishing step (e), a plurality of sintered bodies 1 are put into a barrel-type container, and an appropriate motion is given to the container, whereby the sintered bodies 1 in the container are mutually connected. The one sintered body 1 exhibits a polishing action with respect to the other sintered body 1. Thus, the sliding surface 5 provided on the outer peripheral surface of the sintered body 1 can be polished without separately supplying an abrasive such as a medium, and any object is opened on the surface of the sintered body 1 after polishing. A situation where the hole 4 is stuck can be prevented.

また、バレル型容器の回転により、当該容器内で複数の焼結体１を相互に衝突させることで、各焼結体１の表面に上記衝突による凹部６が形成され、この凹部６には、後の含油工程（ｆ）にて潤滑油７が供給される。よって、少なくとも上述の工程（ｅ）および（ｆ）を経て製造された焼結金属部品であれば、相手部材との相対摺動時、摺動面５に隣接する凹部６に保持された潤滑油７が摺動面５上に供給される。従って、例えば図６に示すように、含油直後には焼結体１全体を覆っていた潤滑油７（図５を参照）が、温度低下による内部への引き込み等により、あるいは他部材との組立時に生じる摺動面５からの拭き取り等により摺動面５上に存在しない場合でも、早急な潤滑油７の供給を図ることで、摺動部における潤滑油不足を解消して、異音の発生や摺動磨耗を抑制することができる。   Further, by rotating the barrel type container, the plurality of sintered bodies 1 are caused to collide with each other in the container, thereby forming a concave portion 6 due to the collision on the surface of each sintered body 1. Lubricating oil 7 is supplied in the subsequent oil impregnation step (f). Therefore, if it is a sintered metal part manufactured through at least the above-mentioned steps (e) and (f), the lubricating oil held in the recess 6 adjacent to the sliding surface 5 at the time of relative sliding with the counterpart member 7 is supplied on the sliding surface 5. Therefore, for example, as shown in FIG. 6, the lubricating oil 7 (see FIG. 5) covering the entire sintered body 1 immediately after the oil impregnation is drawn into the interior due to a temperature drop or assembly with other members. Even if it does not exist on the sliding surface 5 due to occasional wiping from the sliding surface 5, it is possible to eliminate the lack of lubricating oil in the sliding portion and generate abnormal noise by promptly supplying the lubricating oil 7. And sliding wear can be suppressed.

なお、上述の共ずりバレル研磨においては、所望の研磨作用および凹部６の形成が達成されるよう、その容器サイズに対する焼結体１のサイズやその投入量、あるいは当該容器の運動態様（回転数やストローク速度、処理時間など）を適正に定めるのがよい。逆に言えば、適正な上記条件下で焼結体１に共ずりバレル処理を施すことで、はじめて所要の研磨作用および油溜りとなり得る凹部６の形成が可能となる。   In the above-described joint barrel polishing, the size of the sintered body 1 with respect to the container size and the amount of the sintered body 1 or the movement mode (the number of rotations) of the container so as to achieve a desired polishing action and formation of the recess 6 And stroke speed, processing time, etc.) should be set appropriately. Conversely, by subjecting the sintered body 1 to a barrel treatment under appropriate conditions, it is possible to form a recess 6 that can be a required polishing action and an oil reservoir for the first time.

また、この実施形態のように、焼結体１が円筒状をなすものである場合、その外面の大部分が平滑な曲面となる。そのため、相互の衝突により鋭部が欠けて、この欠けた部分が焼結体１の表面開孔４に刺さる（はまり込む）可能性も低い。また、衝突の大部分は、焼結体１の外周面同士で生じることから、衝突による変形は広範囲にわたって生じ、かつその変形は内部空孔３によって吸収されるので、その周囲に盛り上がりや角を生じる可能性も低い。よって、円筒状をなす焼結体１であれば、潤滑油７の保持容積を確保する点で、あるいは、隣接する摺動面５の面精度を確保する点で非常に好適である。   Moreover, when the sintered compact 1 is what makes a cylindrical shape like this embodiment, most of the outer surfaces become a smooth curved surface. Therefore, there is a low possibility that sharp portions are missing due to mutual collision, and the missing portions are stuck (inserted) into the surface openings 4 of the sintered body 1. In addition, since most of the collision occurs between the outer peripheral surfaces of the sintered body 1, deformation due to the collision occurs over a wide range, and the deformation is absorbed by the internal holes 3. It is also unlikely to occur. Therefore, the sintered body 1 having a cylindrical shape is very suitable in terms of securing the holding volume of the lubricating oil 7 or securing the surface accuracy of the adjacent sliding surface 5.

また、この実施形態では、共ずりバレル研磨工程（ｅ）の前に、サイジング工程（ｃ）を設けるようにしたので、共ずりバレルにより形成した凹部６をサイジングにより消滅させてしまう恐れもない。   Further, in this embodiment, since the sizing step (c) is provided before the common barrel polishing step (e), there is no possibility that the concave portion 6 formed by the common barrel barrel is eliminated by sizing.

また、この焼結体１を、例えばトルクリミッタ用の内輪に用いる場合、摺動面５の硬度向上を図る必要があるが、その場合には、サイジング工程（ｃ）の後でかつ共ずりバレル工程（ｅ）の前に、熱処理工程（ｄ）を設けることが好ましい。サイジング工程（ｃ）の後に熱処理を実施するのであれば、過度な荷重を必要とすることなくサイジングを実施することができ、サイジングによる加工精度も高くできる。また、共ずりバレル工程（ｅ）の前に硬度向上のための熱処理を実施しておけば、後の相互研磨工程で、熱処理により表面に生じる酸化皮膜などの異物を除去することができるためである。   Further, when this sintered body 1 is used for an inner ring for a torque limiter, for example, it is necessary to improve the hardness of the sliding surface 5. In this case, after the sizing step (c), the joint barrel is used. It is preferable to provide a heat treatment step (d) before the step (e). If heat treatment is performed after the sizing step (c), sizing can be performed without requiring an excessive load, and the processing accuracy by sizing can be increased. In addition, if heat treatment for improving the hardness is performed before the joint barrel step (e), foreign matters such as an oxide film formed on the surface by the heat treatment can be removed in the subsequent mutual polishing step. is there.

なお、図１に示す製造方法の流れはあくまでも一例に過ぎない。相互研磨工程としての共ずりバレル工程（ｅ）および含油工程（ｆ）とを有する限りにおいて、他の工程の組合せは任意である。また、上記工程以外に、例えば共ずりバレル工程（ｅ）の後、含油工程（ｆ）の前に、バレル研磨により焼結体からコンタミなどの不要物を除去するための洗浄工程を設けることも可能である。   Note that the flow of the manufacturing method shown in FIG. 1 is merely an example. As long as it has the joint barrel step (e) and the oil impregnation step (f) as the mutual polishing step, the combination of other steps is arbitrary. In addition to the above steps, for example, after the common barrel step (e) and before the oil impregnation step (f), a cleaning step may be provided for removing unnecessary substances such as contaminants from the sintered body by barrel polishing. Is possible.

以上の説明に係る焼結金属部品は、例えば各種事務機器等におけるブレーキ装置や紙の重送防止装置、特にプリンタや複写機等における紙の重送防止機構をなすトルクリミッタ用の内輪として使用することができる。以下、上述の焼結金属部品を組み込んだトルクリミッタ、およびその使用態様について説明する。なお、内輪としての焼結金属部品に関する説明につき、既述の符号を付したものに関しては、その説明を省略する。   The sintered metal parts according to the above description are used, for example, as an inner ring for a torque limiter that forms a mechanism for preventing paper double feeding in a brake device, paper double feeding prevention device, particularly a printer or a copying machine in various office equipments. be able to. Hereinafter, a torque limiter incorporating the above-described sintered metal part and its usage mode will be described. In addition, about the description regarding the sintered metal component as an inner ring | wheel, the description is abbreviate | omitted about what attached the above-mentioned code | symbol.

図７は、トルクリミッタの断面図を示している。このトルクリミッタは、例えばプリンタや複写機の給紙装置の紙の重送防止機構として好適に使用されるもので、上記工程を経て製造された内輪１１とその外側に回転自在に配設される外輪１２と、外輪１２と内輪１１との間に組み込まれる締結力付与部材としてのコイルばね１３と、外輪１２の一端に固定され、外輪１２と一体に回転する環状部材１６とを主たる構成要素として備える。このうち、コイルばね１３は、主に、内側に配置された内輪１１の外周面（摺動面５）を締め付ける小径部１３ａと、小径部１３ａと連続し、かつ小径部１３ａより大径の大径部１３ｂとからなる。また、この図示例では、小径部１３ａの端部を折曲してなる一方の折曲部１４を、外輪１２の内側端面に設けた凹部に嵌合すると共に、大径部１３ｂの端部を折曲してなる他方の折曲部１５を、外輪１２に固定した環状部材１６の内側端面に設けた凹部に嵌合することで、コイルばね１３を外輪１２に固定している。   FIG. 7 shows a cross-sectional view of the torque limiter. This torque limiter is preferably used as a paper double feed prevention mechanism of a paper feeder of a printer or a copier, for example, and is rotatably disposed on the inner ring 11 manufactured through the above steps and the outside thereof. The main components are an outer ring 12, a coil spring 13 as a fastening force applying member incorporated between the outer ring 12 and the inner ring 11, and an annular member 16 fixed to one end of the outer ring 12 and rotating integrally with the outer ring 12. Prepare. Among these, the coil spring 13 is mainly connected to the small-diameter portion 13a for tightening the outer peripheral surface (sliding surface 5) of the inner ring 11 disposed on the inner side and the small-diameter portion 13a, and has a larger diameter than the small-diameter portion 13a. It consists of a diameter part 13b. Further, in this illustrated example, one bent portion 14 formed by bending the end portion of the small diameter portion 13a is fitted into a concave portion provided on the inner end surface of the outer ring 12, and the end portion of the large diameter portion 13b is fitted. The coil spring 13 is fixed to the outer ring 12 by fitting the other bent part 15 formed by bending into a recess provided on the inner end surface of the annular member 16 fixed to the outer ring 12.

上記構成のトルクリミッタにおいて、例えば環状部材１６の側から見て、内輪１１をコイルばね１３の巻方向と同方向に回転させると、コイルばね１３の小径部１３ａは内輪１１から縮径する向きの力を受け、内輪１１を締付ける。このため、内輪１１の回転はコイルばね１３を介して外輪１２に伝達され、外輪１２が内輪１１と同じ方向に回転する。   In the torque limiter having the above configuration, for example, when the inner ring 11 is rotated in the same direction as the winding direction of the coil spring 13 when viewed from the annular member 16 side, the small-diameter portion 13a of the coil spring 13 is in a direction to reduce the diameter from the inner ring 11. The inner ring 11 is tightened by receiving the force. For this reason, the rotation of the inner ring 11 is transmitted to the outer ring 12 via the coil spring 13, and the outer ring 12 rotates in the same direction as the inner ring 11.

外輪１２への負荷（回転に抗する負荷）が増し、小径部１３ａの内輪１１への締付け力が内輪１１から受ける回転トルクを下回ると、内輪１１と小径部１３ａとの間で滑りが生じ、外輪１２への回転トルクの伝達が遮断される。   When the load on the outer ring 12 (load against the rotation) increases and the tightening force of the small-diameter portion 13a on the inner ring 11 is less than the rotational torque received from the inner ring 11, slip occurs between the inner ring 11 and the small-diameter portion 13a. Transmission of rotational torque to the outer ring 12 is interrupted.

また、内輪１１をコイルばね１３の巻方向と逆方向に回転させると、コイルばね１３の小径部１３ａが拡径し、内輪１１と小径部１３ａとの間で滑りが生じることで、外輪１２への回転トルクの伝達が遮断される。   Further, when the inner ring 11 is rotated in the direction opposite to the winding direction of the coil spring 13, the small diameter portion 13 a of the coil spring 13 expands, and slipping occurs between the inner ring 11 and the small diameter portion 13 a, so that the outer ring 12 is moved. The transmission of rotational torque is interrupted.

上述の如く作動するトルクリミッタにおいては、コイルばね１３の小径部１３ａと内輪１１との間である程度の締め代をもたせて嵌合させる必要があり、装着時に内輪１１の外周面に付着した潤滑油７をばねの内周面が掻き取ってしまう。そのため、摺動面５上に残存する潤滑油の量にばらつきが生じ、場合によっては、図６に示すように、潤滑油７が摺動面５上に不足する事態が考えられる。これに対して、本発明に係る方法で製造された内輪１１であれば、摺動面５に形成した凹部６が油溜りの役割を果たし、外輪１２との相対回転に伴い、凹部６に保持された潤滑油７を摺動面５上に供給することができる。そのため、摺動時、特に組立て直後の最初の摺動開始時における潤滑油不足を解消して、異音の発生や接触による摺動摩耗の低減を図ることができる。   In the torque limiter that operates as described above, it is necessary to provide a certain amount of tightening allowance between the small-diameter portion 13a of the coil spring 13 and the inner ring 11, and the lubricating oil adhering to the outer peripheral surface of the inner ring 11 at the time of mounting. 7 is scraped off by the inner peripheral surface of the spring. Therefore, the amount of lubricating oil remaining on the sliding surface 5 varies, and in some cases, the lubricating oil 7 may be insufficient on the sliding surface 5 as shown in FIG. On the other hand, in the case of the inner ring 11 manufactured by the method according to the present invention, the concave portion 6 formed on the sliding surface 5 serves as an oil reservoir, and is held in the concave portion 6 with relative rotation with the outer ring 12. The applied lubricating oil 7 can be supplied onto the sliding surface 5. Therefore, it is possible to eliminate the shortage of lubricating oil at the time of sliding, particularly at the beginning of the first sliding immediately after assembly, and to reduce the sliding wear due to generation of abnormal noise and contact.

また、通常、コイルばね１３の内周面と内輪１１の外周面との間で摺動を開始する際のトルク値は、これらの嵌め合い寸法を適宜に設定することにより制御される。ここで、上述のように、サイジング工程（ｃ）の後に共ずりバレル工程（ｅ）を経て得られた内輪１１であれば、摺動面５の外径寸法やその面精度を高めることができ、摺動開始時のトルク値を精度よく制御することができる。   In general, the torque value at the start of sliding between the inner peripheral surface of the coil spring 13 and the outer peripheral surface of the inner ring 11 is controlled by appropriately setting these fitting dimensions. Here, as described above, if the inner ring 11 is obtained through the joint barrel step (e) after the sizing step (c), the outer diameter size and surface accuracy of the sliding surface 5 can be increased. The torque value at the start of sliding can be accurately controlled.

以上、トルクリミッタ用の内輪に本発明を適用した場合を説明したが、本発明は、この用途に限定されるものではない。上述の共ずりバレルにより研磨可能な摺動面を有し、かつ内部に保持した潤滑油を摺動面に供給可能なものである限りにおいて、例えばコイルばね式以外のトルク伝達、遮断を可能とする機構、あるいは正逆双方向の回転によるトルク伝達、遮断を可能とする機構を有するトルクリミッタの摺動部品、さらには他の摺動機械部品に対しても本発明を適用することができる。   The case where the present invention is applied to the inner ring for torque limiter has been described above, but the present invention is not limited to this application. As long as it has a sliding surface that can be polished by the above-described joint barrel and can supply lubricating oil held inside to the sliding surface, for example, torque transmission other than the coil spring type can be transmitted and cut off. The present invention can also be applied to a sliding part of a torque limiter having a mechanism for performing torque transmission by a forward / reverse bidirectional rotation and a mechanism capable of interrupting, and also to other sliding machine parts.

また、以上の説明では、潤滑流体として潤滑油を使用した場合を説明したが、これは例示に過ぎない。焼結金属部品の内部空孔に保持され、かつ相対摺動時、摺動面上に滲み出るものである限りにおいて、グリースをはじめとする各種潤滑剤が使用可能である。   Moreover, although the above description demonstrated the case where lubricating oil was used as a lubricating fluid, this is only an illustration. Various lubricants including grease can be used as long as they are held in the internal holes of the sintered metal part and ooze out on the sliding surface during relative sliding.

本発明の一実施形態に係る焼結金属部品の製造方法のフローチャートである。It is a flowchart of the manufacturing method of the sintered metal component which concerns on one Embodiment of this invention. 焼結工程を経た後の焼結体の表面周辺の拡大断面図である。It is an expanded sectional view of the surface periphery of the sintered compact after passing through a sintering process. サイジング工程を経た後の焼結体の摺動面周辺の拡大断面図である。It is an expanded sectional view of the sliding surface periphery of the sintered compact after passing through a sizing process. 共ずりバレル工程を経た後の焼結体の摺動面周辺の拡大断面図である。It is an expanded sectional view of the sliding surface periphery of the sintered compact after passing through a joint barrel process. 含油工程を経た後の焼結体の摺動面周辺の拡大断面図である。It is an expanded sectional view of the sliding surface periphery of the sintered compact after passing through an oil impregnation process. 潤滑油の引き込み時における焼結体の摺動面周辺の拡大断面図である。It is an expanded sectional view around the sliding surface of a sintered compact at the time of drawing in lubricating oil. 本発明により製造された内輪を組み込んだトルクリミッタの断面図である。It is sectional drawing of the torque limiter incorporating the inner ring | wheel manufactured by this invention.

符号の説明Explanation of symbols

１ 焼結体
２ 金属粉末
３ 内部空孔
４ 表面開孔
５ 摺動面
７ 凹部
８ 潤滑油
１１ 内輪
１２ 外輪
１３ コイルばね１３
１３ａ 小径部 DESCRIPTION OF SYMBOLS 1 Sintered body 2 Metal powder 3 Internal hole 4 Surface opening 5 Sliding surface 7 Recess 8 Lubricating oil 11 Inner ring 12 Outer ring 13 Coil spring 13
13a Small diameter part

Claims (6)

金属粉末を圧粉成形し、焼結して得られる多孔質の焼結体で、その内部空孔に潤滑流体が含浸されると共に、他部材との摺動面を有する焼結金属部品の製造方法であって、
複数の焼結体を容器に投入し、該容器の運動により、複数の前記焼結体を相互に研磨材として作用させ前記摺動面を研磨すると共に、複数の前記焼結体を相互に衝突させ前記摺動面に衝突による凹部を形成する工程と、
前記焼結体の前記内部空孔および前記凹部に前記潤滑流体を供給する工程とを少なくとも備える焼結金属部品の製造方法。 Manufacture of sintered metal parts, which are porous sintered bodies obtained by compacting and sintering metal powder, and whose internal pores are impregnated with a lubricating fluid and have sliding surfaces with other members A method,
A plurality of sintered bodies are placed in a container, and the movement of the container causes the plurality of sintered bodies to act as abrasives to polish the sliding surface, and the plurality of sintered bodies collide with each other. And forming a recess due to a collision on the sliding surface;
A method of manufacturing a sintered metal part comprising at least a step of supplying the lubricating fluid to the internal holes and the recesses of the sintered body. 前記相互研磨工程の前に、前記摺動面をサイジングする工程をさらに備える請求項１記載の焼結金属部品の製造方法。   The method for manufacturing a sintered metal part according to claim 1, further comprising a step of sizing the sliding surface before the mutual polishing step. 前記サイジング工程の後でかつ前記相互研磨工程の前に、前記焼結体に対して熱処理を施し、前記摺動面の硬度向上を図る熱処理工程をさらに備える請求項２記載の焼結金属部品の製造方法。   3. The sintered metal part according to claim 2, further comprising a heat treatment step of performing a heat treatment on the sintered body after the sizing step and before the mutual polishing step to improve the hardness of the sliding surface. Production method. 請求項１〜３の何れかに記載の方法で製造された焼結金属部品。   The sintered metal part manufactured by the method in any one of Claims 1-3. 筒状をなし外周に前記摺動面を有するもので、その外側に配した前記他部材としてのコイルばねから締付け力を受ける向きに回転する際、前記コイルばねとの間でトルク伝達を行い、該伝達トルクが所定量を超えた場合、前記摺動面と前記コイルばねとの間で相対摺動を行う請求項４記載の焼結金属部品。   It has a cylindrical shape and has the sliding surface on the outer periphery, and when rotating in a direction to receive a tightening force from the coil spring as the other member arranged on the outer side, torque is transmitted between the coil spring, The sintered metal part according to claim 4, wherein when the transmission torque exceeds a predetermined amount, relative sliding is performed between the sliding surface and the coil spring. 請求項５記載の焼結金属部品を備えたトルクリミッタ。   A torque limiter comprising the sintered metal part according to claim 5.

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