JPH0988962A - Manufacture of bearing - Google Patents
Manufacture of bearingInfo
- Publication number
- JPH0988962A JPH0988962A JP24185995A JP24185995A JPH0988962A JP H0988962 A JPH0988962 A JP H0988962A JP 24185995 A JP24185995 A JP 24185995A JP 24185995 A JP24185995 A JP 24185995A JP H0988962 A JPH0988962 A JP H0988962A
- Authority
- JP
- Japan
- Prior art keywords
- bearing
- die
- sintered body
- peripheral surface
- core rod
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Forging (AREA)
- Powder Metallurgy (AREA)
- Sliding-Contact Bearings (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、粉末冶金による軸受の
製造方法に係わり、特に、内径を小さくしてなる複数の
軸受面が軸方向に分離して並んでいる軸受の製造方法に
関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a bearing by powder metallurgy, and more particularly to a method of manufacturing a bearing in which a plurality of bearing surfaces each having a small inner diameter are arranged side by side in the axial direction.
【０００２】[0002]
【従来の技術】粉末冶金により製造される焼結含油軸受
として、いわゆるツインベアリングがある。ツインベア
リングは、内径を小さくしてなる軸受面を両端側にそれ
ぞれ有し、両軸受面間では内径が大きくなっているもの
である。同様に、３つ以上の軸受面が軸方向に分離して
並んでいる軸受もある。軸受による軸の支持の安定性を
高めるには、軸方向においてなるべく離れた複数の位置
で軸を支持すればよいが、別体の複数の軸受を用いるの
では、これら軸受を同軸に配するのに困難がある。ま
た、長い１つの軸受を用いることも考えられるが、それ
では、軸受と軸との間の摩擦抵抗による損失が大きくな
るとともに、磨耗が大きくなって短寿命化を招く。これ
に対して、ツインベアリングは、複数の軸受面の同軸性
に問題はなく、また、運転時の損失を小さくできるとと
もに、長寿命化できる利点がある。2. Description of the Related Art As a sintered oil-impregnated bearing manufactured by powder metallurgy, there is a so-called twin bearing. The twin bearing has bearing surfaces each having a smaller inner diameter on both end sides, and has a larger inner diameter between the both bearing surfaces. Similarly, in some bearings, three or more bearing surfaces are arranged side by side in the axial direction. In order to improve the stability of the shaft support by the bearings, it is sufficient to support the shafts at a plurality of positions as far apart as possible in the axial direction, but if a plurality of separate bearings are used, these bearings are arranged coaxially. Have difficulty. It is also conceivable to use one long bearing, but this causes a large loss due to the frictional resistance between the bearing and the shaft and causes a large amount of wear, resulting in a shortened service life. On the other hand, the twin bearing has the advantages that there is no problem with the coaxiality of the plurality of bearing surfaces, the loss during operation can be reduced, and the service life can be extended.
【０００３】ツインベアリングの製造には、内周面の切
削加工が難しいことなどから、焼結体を金型により再圧
縮する矯正が利用されている。そして、従来は、例えば
特開昭61-165019 号公報に記載されているような方法で
製造が行われていた。この従来の方法では、まず内径も
外径も全体的に均一な円筒状の圧粉体を成形する。そし
て、この圧粉体を焼結した後、焼結体の外周面を切削加
工して、この外周面の軸方向中間部の一部の径を小さく
する。その後、コアロッド、ダイ、下パンチおよび上パ
ンチを備えた矯正用金型により焼結体を矯正する。焼結
体の内周面を形成するコアロッドの外周面および焼結体
の外周面を形成するダイの内周面は、いずれも径が均一
であり、円柱面になっている。そして、コアロッドおよ
びダイ間で両パンチにより焼結体を軸方向に圧縮する。
それに伴い、焼結体における外周面に径小部のある部分
が径方向外方へ変形し、この部分の内径が大きくなる。
これにより、軸方向に分離して並んだ複数の軸受面が形
成されることになる。しかし、この従来の方法では、矯
正の前に切削加工を行っているため、工程が多くなり、
コストが高くなる問題がある。In the manufacture of twin bearings, straightening, in which the sintered body is recompressed with a mold, is used because it is difficult to cut the inner peripheral surface. In the past, manufacturing was carried out by the method described in, for example, JP-A-61-165019. In this conventional method, first, a cylindrical green compact having an inner diameter and an outer diameter that are entirely uniform is formed. Then, after sintering the green compact, the outer peripheral surface of the sintered body is cut to reduce the diameter of a part of the axially intermediate portion of the outer peripheral surface. After that, the sintered body is straightened by a straightening die having a core rod, a die, a lower punch and an upper punch. The outer peripheral surface of the core rod forming the inner peripheral surface of the sintered body and the inner peripheral surface of the die forming the outer peripheral surface of the sintered body both have a uniform diameter and are cylindrical surfaces. Then, the sintered body is axially compressed between the core rod and the die by both punches.
As a result, the portion of the sintered body having the small diameter portion on the outer peripheral surface is deformed radially outward, and the inner diameter of this portion increases.
As a result, a plurality of bearing surfaces that are separated and arranged in the axial direction are formed. However, in this conventional method, since the cutting process is performed before straightening, the number of steps increases,
There is a problem of high cost.
【０００４】これに対して、特開平2-8302号公報には、
切削加工の不要な製造方法が提案されている。この従来
の方法では、一端部の内径を小さくしたほぼ円筒状の圧
粉体を成形する。この粉末成形時に形成される内周面の
径小部がそのまま１つの軸受面になる。一方、圧粉体の
外径は全体的に均一である。また、矯正用金型は、コア
ロッドは円柱状であるが、段付きのダイを用いる。すな
わち、ダイの内径は、上部よりも下部が小さくなってい
る。そして、ダイの中に焼結体をその他端側から押し込
んでいくと、この焼結体の他端部がダイの径小部により
絞られて、焼結体の他端部の内周面に前記一端部の軸受
面と同径の軸受面が形成される。しかし、この従来の方
法では、矯正に際して、焼結体の一端部は大きな圧縮を
受け得ないため、この一端部の強度が弱い問題がある。
なお、粉末成形に際しては、圧粉体の一端部の内径を小
さく形成するために、段付きのコアロッドが用いられ、
圧粉体の一端部の内周側の密度が高くなるが、これによ
り強度上の効果を出すためには、圧粉体の一端部の内径
と他の部分の内径との差をある程度大きくしなければな
らない。しかし、この差を大きくすると、矯正時に、焼
結体の一端部の下方に大きな空間部が生じ、焼結体に不
定な変形が生じるなどの支障が生じるおそれがある。On the other hand, Japanese Patent Laid-Open No. 2-8302 discloses that
A manufacturing method that does not require cutting has been proposed. In this conventional method, an approximately cylindrical green compact having a smaller inner diameter at one end is formed. The small diameter portion of the inner peripheral surface formed at the time of powder molding directly becomes one bearing surface. On the other hand, the outer diameter of the green compact is uniform throughout. Further, in the straightening die, the core rod has a cylindrical shape, but a stepped die is used. That is, the inner diameter of the die is smaller at the bottom than at the top. Then, when the sintered body is pushed into the die from the other end side, the other end portion of this sintered body is squeezed by the small diameter portion of the die and the inner peripheral surface of the other end portion of the sintered body is squeezed. A bearing surface having the same diameter as the bearing surface at the one end is formed. However, in this conventional method, since one end of the sintered body cannot be subjected to a large compression at the time of straightening, there is a problem that the strength of this one end is weak.
At the time of powder molding, a stepped core rod is used to reduce the inner diameter of one end of the green compact.
The density on the inner peripheral side of one end of the green compact increases, but in order to obtain the effect on strength by this, the difference between the inner diameter of the one end of the green compact and the inner diameter of the other part should be increased to some extent. There must be. However, if this difference is increased, a large space may be formed below one end of the sintered body at the time of correction, which may cause trouble such as indefinite deformation of the sintered body.
【０００５】[0005]
【発明が解決しようとする課題】前述のように、複数の
軸受面が軸方向に分離して並んでいる軸受を粉末冶金に
より製造するのに、従来は、焼結体の外周面を切削加工
してから、焼結体を矯正していたため、工程が多くな
り、コストが高くなる問題があった。また、一端部の内
径を小さくした圧粉体を成形し、この圧粉体を焼結して
なる焼結体の他端部を矯正で絞る方法も提案されている
が、この方法では、軸受面をなす前記一端部の強度が弱
くなる、あるいは、矯正時に、焼結体と金型との間に大
きな空間部が生じる問題があった。As described above, in the case of manufacturing a bearing in which a plurality of bearing surfaces are arranged side by side in the axial direction by powder metallurgy, conventionally, the outer peripheral surface of the sintered body is cut and processed. After that, since the sintered body was corrected, there was a problem that the number of processes was increased and the cost was increased. Further, a method has been proposed in which a green compact having an inner diameter at one end is formed, and the other end of a sintered body obtained by sintering the green compact is squeezed by straightening. There is a problem that the strength of the one end forming the surface becomes weak, or a large space portion is generated between the sintered body and the mold during the correction.
【０００６】本発明は、このような問題点を解決しよう
とするもので、複数の軸受面が軸方向に分離して並んで
いる軸受を粉末冶金により製造するにあたって、製造に
かかるコストを下げるとともに、全ての軸受面部分の強
度を高められ、かつ、矯正でも支障が生じないようにす
ることを目的とする。The present invention is intended to solve such a problem, and when manufacturing a bearing in which a plurality of bearing surfaces are separated and arranged in the axial direction by powder metallurgy, the manufacturing cost is reduced and The purpose is to increase the strength of all the bearing surface parts and prevent any problems even with correction.
【０００７】[0007]
【課題を解決するための手段】本発明は、原料粉末を圧
縮して筒状の圧粉体を成形する粉末成形工程と、成形さ
れた圧粉体を加熱して焼結する焼結工程と、焼結された
焼結体を再圧縮して所定形状に矯正する矯正工程とを備
え、内径を小さくしてなる複数の軸受面が軸方向に分離
して並んでいる軸受の製造方法である。そして、前記目
的を達成するために、前記粉末成形工程では、内径が全
体的に均一であるとともに、外径が一端側から他端側へ
向けて段階的に大きくなる筒状の圧粉体を成形し、ま
た、前記矯正工程では、軸受の内周面を形成するコアロ
ッドと、軸受の外周面を形成するダイと、軸受の端面を
形成するパンチとを備え、前記コアロッドの外径が均一
で、前記ダイの内径が一端側から他端側へ向けて段階的
に大きくなる矯正用金型を用い、前記複数の軸受面に相
当する部分のみで焼結体を前記ダイにより径方向内方へ
コアロッドに押し付けるまで変形させるものである。SUMMARY OF THE INVENTION The present invention comprises a powder molding step of compressing a raw material powder to form a cylindrical green compact, and a sintering step of heating and sintering the green compact. A method of manufacturing a bearing in which a plurality of bearing surfaces each having a smaller inner diameter are arranged side by side in the axial direction, and a straightening step of recompressing the sintered sintered body to straighten it into a predetermined shape. . Then, in order to achieve the above-mentioned object, in the powder molding step, a cylindrical green compact whose inner diameter is generally uniform and whose outer diameter gradually increases from one end side to the other end side is obtained. In addition, the core rod that forms the inner peripheral surface of the bearing, the die that forms the outer peripheral surface of the bearing, and the punch that forms the end surface of the bearing are formed, and the outer diameter of the core rod is uniform. Using a straightening die in which the inner diameter of the die gradually increases from one end side to the other end side, the sintered body is radially inward by the die only at the portions corresponding to the plurality of bearing surfaces. It deforms until it is pressed against the core rod.
【０００８】この構成において、粉末成形工程の段階
で、圧粉体の外径を一端側から他端側へ向けて段階的に
大きく形成することは、その後、矯正工程のみにより、
軸方向に分離して並んでいる複数の軸受面を形成する手
段をなしている。軸受面の数が２の場合を例に採ると、
圧粉体の外周面の段部は少なくとも１つあればよい。そ
して、矯正工程時、焼結体をその外周面の径小部側から
矯正用金型のダイ内に押し込んでいくと、焼結体の外周
面の径小部の先端側のみがダイにおける前記径小部の外
径よりも所定量内径の小さい部分に押し込まれるととも
に、焼結体の外周面の径大部がダイにおける前記径大部
の外径よりも所定量内径の小さい部分に押し込まれる。
ここで、ダイの前者の内径は、後者の内径よりも小さ
い。そして、前記押し込みにより、焼結体は、部分的に
絞られてコアロッドに押し付けられ、このコアロッドに
押し付けられた部分が軸受面となるが、この軸受面は、
焼結体の径小部の先端側に相当する部分と径大部に相当
する部分とにのみ形成され、軸受面間においては、焼結
体の外周面の径小部における径大部側の部分がダイにお
ける前記径小部の外径よりも所定量内径の小さい部分に
押し込まれないことにより、矯正された焼結体の内周面
は軸受面よりも内径が大きくなる。In this structure, the step of forming the outer diameter of the green compact stepwise from the one end side to the other end side in the powder molding step is performed only by the straightening step thereafter.
It forms a means for forming a plurality of bearing surfaces that are separated from each other in the axial direction. Taking the case of two bearing surfaces as an example,
At least one step on the outer peripheral surface of the green compact is sufficient. Then, during the straightening step, when the sintered body is pushed into the die of the straightening die from the smaller diameter portion side of the outer peripheral surface, only the tip side of the smaller diameter portion of the outer peripheral surface of the sintered body becomes It is pushed into a portion whose inner diameter is smaller than the outer diameter of the small diameter portion by a predetermined amount, and the large diameter portion of the outer peripheral surface of the sintered body is pushed into a portion whose inner diameter is smaller than the outer diameter of the large diameter portion by a predetermined amount. .
Here, the former inner diameter of the die is smaller than the latter inner diameter. Then, by the pushing, the sintered body is partially squeezed and pressed against the core rod, and the portion pressed against the core rod becomes a bearing surface.
It is formed only in the portion corresponding to the tip side of the small diameter portion of the sintered body and the portion corresponding to the large diameter portion, and between the bearing surfaces, the large diameter portion side of the small diameter portion of the outer peripheral surface of the sintered body is formed. Since the portion is not pushed into the portion of the die having the inner diameter smaller than the outer diameter of the small diameter portion by the predetermined amount, the inner peripheral surface of the corrected sintered body has the inner diameter larger than the bearing surface.
【０００９】[0009]
【発明の実施形態】以下、本発明の軸受の製造方法の一
実施例について、図１から図４を参照しながら説明す
る。図１に実線で示してあるのは、粉末冶金により製造
された焼結含油軸受１である。この軸受１は、ほぼ円筒
状の回転体形状になっており、内周面の両端部は、それ
ぞれ内周面中間部２よりも内径が小さい第１の軸受面３
および第２の軸受面４になっている。これら軸受面３，
４は、それぞれ円柱面をなし、内径が等しいとともに、
互いに同軸になっている。また、軸受１の外周面は、第
１の軸受面３側の一端部が外周面中間部５よりも外径の
小さい径小部６になっており、第２の軸受面４側の他端
部が外周面中間部５よりも外径の大きい径大部７になっ
ている。外周面中間部５と径小部６および径大部７との
間にはそれぞれ段部８，９がある。BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a method of manufacturing a bearing according to the present invention will be described below with reference to FIGS. A solid line in FIG. 1 is a sintered oil-impregnated bearing 1 manufactured by powder metallurgy. The bearing 1 is in the shape of a substantially cylindrical rotating body, and both ends of the inner peripheral surface of the first bearing surface 3 have an inner diameter smaller than that of the intermediate portion 2 of the inner peripheral surface.
And the second bearing surface 4. These bearing surfaces 3,
4 each have a cylindrical surface and have the same inner diameter,
They are coaxial with each other. Further, the outer peripheral surface of the bearing 1 has a small-diameter portion 6 having an outer diameter smaller than that of the intermediate portion 5 on the first bearing surface 3 side, and the other end on the second bearing surface 4 side. The portion is a large-diameter portion 7 having an outer diameter larger than that of the intermediate portion 5 on the outer peripheral surface. Step portions 8 and 9 are provided between the outer peripheral surface intermediate portion 5 and the small diameter portion 6 and the large diameter portion 7, respectively.
【００１０】図２は、前記軸受１の製造に用いられる粉
末成形用金型を示している。この粉末成形用金型は、上
下方向を軸方向としており、コアロッド11と段付きダイ
12と下パンチ13と上パンチ14とを備えている。コアロッ
ド11は、ダイ12内に同軸的に位置しており、軸受１とな
る圧粉体1Aの内周面を形成するものである。そして、コ
アロッド11における圧粉体1Aの成形に関わる部分は円柱
状になっている。ダイ12は、圧粉体1Aの外周面を形成す
るもので、その成形に関わるダイ12の内周面は、円柱面
状の径小部16を下側に有しているとともに、この径小部
16よりも内径の大きい円柱面状の径大部17を上部に有し
ており、これら径小部16および径大部17間に段部18があ
る。また、円筒状の下パンチ13は、前記径小部16におい
てコアロッド11およびダイ12間に下方から上下摺動自在
に嵌合されており、圧粉体1Aの一端面を形成するもので
ある。さらに、円筒状の上パンチ14は、前記径大部17に
おいてコアロッド11およびダイ12間に上方から上下摺動
自在にかつ挿脱自在に嵌合されるもので、圧粉体1Aの他
端面を形成するものである。FIG. 2 shows a powder molding die used for manufacturing the bearing 1. This powder molding die has a vertical direction as the axial direction, and the core rod 11 and the stepped die are
It has 12 and lower punches 13 and upper punches 14. The core rod 11 is positioned coaxially within the die 12 and forms the inner peripheral surface of the powder compact 1A that serves as the bearing 1. The portion of the core rod 11 related to the molding of the green compact 1A has a columnar shape. The die 12 forms the outer peripheral surface of the green compact 1A, and the inner peripheral surface of the die 12 involved in the molding has a cylindrical surface-shaped small diameter portion 16 on the lower side, and this small diameter. Department
A cylindrical large-diameter portion 17 having an inner diameter larger than that of 16 is provided at the upper part, and a step portion 18 is provided between the small-diameter portion 16 and the large-diameter portion 17. The cylindrical lower punch 13 is fitted between the core rod 11 and the die 12 in the small diameter portion 16 so as to be vertically slidable from below, and forms one end surface of the green compact 1A. Further, the cylindrical upper punch 14 is fitted between the core rod 11 and the die 12 in the large-diameter portion 17 so as to be vertically slidable and insertable / detachable from above, and the other end surface of the green compact 1A. To form.
【００１１】図３および図４は、前記軸受１の製造に用
いられる矯正用金型を示している。この矯正用金型は、
上下方向を軸方向としており、コアロッド21と段付きダ
イ22と下パンチ23と上パンチ24とを備えている。コアロ
ッド21は、ダイ22内に同軸的に位置しており、軸受１の
内周面を形成するものである。そして、コアロッド21に
おける軸受１の成形に関わる部分は円柱状になってお
り、外径が均一になっている。ダイ22は、軸受１の外周
面を形成するもので、ダイ22の内径は、下側から上側へ
向けて段階的に大きくなっている。すなわち、ダイ22の
内周面は、円柱面状の径小部26と、その上側に位置しこ
の径小部26よりも内径が大きい円柱面状の径中部27と、
その上側に位置しこの径中部27よりも内径が大きい円柱
面状の径大部28と、その上側に位置しこの径大部28より
も内径が大きい円柱面状の導入部29とを同軸的に有して
おり、径小部26および径中部27間と径中部27および径大
部２８間と径大部２８および導入部29間にはそれぞれ段
部30，31，32がある。ここで、径小部26は軸受１の径小
部６を形成し、径中部27は同外周面中間部５を形成し、
径大部28は同径大部７を形成し、段部30，31は同段部
８，９を形成するものである。また、円筒状の下パンチ
23は、前記径小部26においてコアロッド21およびダイ22
間に下方から上下摺動自在に嵌合されており、軸受１の
一端面を形成するものである。さらに、円筒状の上パン
チ24は、前記径大部28においてコアロッド21およびダイ
22間に上方から上下摺動自在にかつ挿脱自在に嵌合され
るもので、軸受１の他端面を形成するものである。FIG. 3 and FIG. 4 show a straightening die used for manufacturing the bearing 1. This straightening mold is
The vertical direction is the axial direction, and the core rod 21, the stepped die 22, the lower punch 23, and the upper punch 24 are provided. The core rod 21 is positioned coaxially within the die 22 and forms the inner peripheral surface of the bearing 1. The portion of the core rod 21 related to the molding of the bearing 1 has a cylindrical shape and has a uniform outer diameter. The die 22 forms the outer peripheral surface of the bearing 1, and the inner diameter of the die 22 gradually increases from the lower side to the upper side. That is, the inner peripheral surface of the die 22 is a cylindrical surface-shaped small diameter portion 26, and a cylindrical surface-shaped small diameter portion 27 located on the upper side and having an inner diameter larger than the small diameter portion 26,
The cylindrical large-diameter portion 28 located on the upper side and having a larger inner diameter than the middle diameter portion 27 and the cylindrical large-diameter introduction portion 29 located on the upper side and having a larger inner diameter than the large-diameter portion 28 are coaxial. In addition, there are stepped portions 30, 31, 32 between the small diameter portion 26 and the large diameter portion 27, between the large diameter portion 27 and the large diameter portion 28, and between the large diameter portion 28 and the introduction portion 29, respectively. Here, the small diameter portion 26 forms the small diameter portion 6 of the bearing 1, the small diameter portion 27 forms the outer peripheral surface intermediate portion 5, and
The large-diameter portion 28 forms the same-diameter large portion 7, and the step portions 30 and 31 form the same-step portions 8 and 9. Also, cylindrical lower punch
23 is a core rod 21 and a die 22 in the small diameter portion 26.
Fitted in a vertically slidable manner from below to form one end surface of the bearing 1. Further, the cylindrical upper punch 24 has the core rod 21 and the die at the large-diameter portion 28.
It is fitted between the upper and lower parts so as to be vertically slidable and insertable and removable from above, and forms the other end surface of the bearing 1.
【００１２】つぎに、前記軸受１の製造方法について説
明する。まず、前記粉末成形用金型を備えた粉末成形プ
レスにより圧粉体1Aが形成される（粉末成形工程）。こ
の粉末成形工程においては、上パンチ14がダイ12から上
方へ抜けた状態で、このダイ12内に原料粉末が充填され
た後、下降する上パンチ14がダイ12内に嵌合し、図２に
示すように、コアロッド11およびダイ12間で両パンチ1
3，14により原料粉末が加圧されて圧縮されることによ
り、圧粉体1Aが成形される。その後、上パンチ14が上昇
してダイ12から抜けるとともに、ダイ12に対して下パン
チ13が相対的に上昇することにより、成形された圧粉体
1Aがコアロッド11およびダイ12間から抜き出される。Next, a method of manufacturing the bearing 1 will be described. First, the green compact 1A is formed by a powder molding press equipped with the powder molding die (powder molding step). In this powder molding step, with the upper punch 14 being pulled out upward from the die 12, after the raw material powder is filled in the die 12, the descending upper punch 14 is fitted into the die 12, Both punches 1 between core rod 11 and die 12 as shown in
By pressing and compressing the raw material powder by 3, 14, the green compact 1A is molded. After that, the upper punch 14 rises and comes out of the die 12, and the lower punch 13 rises relatively to the die 12, so that the molded green compact is formed.
1A is extracted from between the core rod 11 and the die 12.
【００１３】成形された圧粉体1Aは、図１にも鎖線で示
すように、ほぼ円筒状で、内周面2Aは円柱面をなしてお
り、内径が全体的に均一になっている。一方、圧粉体1A
の内周面は、一端側が円柱面状の径小部6Aになっている
とともに、他端側が径小部6Aよりも外径の大きい円柱面
状の径大部7Aになっており、これら径小部6Aおよび径大
部7A間には段部8Aがある。径小部6Aおよび径大部7Aは互
いに同軸である。As shown by the chain line in FIG. 1, the molded green compact 1A has a substantially cylindrical shape, and the inner peripheral surface 2A has a cylindrical surface, and the inner diameter is uniform throughout. On the other hand, green compact 1A
The inner peripheral surface of the one end side is a cylindrical surface-shaped small diameter portion 6A, and the other end side is a cylindrical surface large diameter portion 7A having a larger outer diameter than the small diameter portion 6A. There is a stepped portion 8A between the small portion 6A and the large diameter portion 7A. The small diameter portion 6A and the large diameter portion 7A are coaxial with each other.
【００１４】その後、成形された圧粉体1Aは、焼結炉に
より加熱されて焼結され、焼結体1Aとなる（焼結工
程）。焼結により圧粉体1Aは若干収縮するが、焼結体1A
は圧粉体1Aとほぼ同形状を有する。そして、焼結体1Aの
径小部6Aの外径は、矯正用金型のダイ22の径小部26の内
径よりも所定量大きいとともに、ダイ22の径中部27の内
径とほぼ等しい。また、焼結体1Aの径小部6Aの軸方向長
さは、ダイ22の径中部27の軸方向長さの２倍程度であ
る。さらに、焼結体1Aの径大部7Aの外径は、ダイ22の径
大部28の内径よりも所定量大きいとともに、ダイ22の導
入部29の内径よりも小さい。前記両所定量は、焼結体1A
の内径と矯正用金型のコアロッド21の外径との差よりも
若干大きい。Thereafter, the compacted green compact 1A is heated in a sintering furnace and sintered to form a sintered body 1A (sintering step). Although the green compact 1A contracts slightly due to sintering, the sintered compact 1A
Has almost the same shape as the green compact 1A. The outer diameter of the small-diameter portion 6A of the sintered body 1A is larger than the inner diameter of the small-diameter portion 26 of the die 22 of the correction die by a predetermined amount and is substantially equal to the inner diameter of the middle-diameter portion 27 of the die 22. Further, the axial length of the small diameter portion 6A of the sintered body 1A is about twice the axial length of the diameter intermediate portion 27 of the die 22. Furthermore, the outer diameter of the large diameter portion 7A of the sintered body 1A is larger than the inner diameter of the large diameter portion 28 of the die 22 by a predetermined amount and smaller than the inner diameter of the introduction portion 29 of the die 22. The above predetermined amount is the sintered body 1A
Is slightly larger than the difference between the inner diameter of and the outer diameter of the core rod 21 of the correction die.
【００１５】焼結工程の後、焼結体1Aは、前記矯正用金
型を備えた矯正プレスにより再圧縮されて所定形状に矯
正される。この矯正工程においては、上昇した下パンチ
23上に径小部6Aが下側になった焼結体1Aが搬入された
後、下パンチ23が下降して焼結体1Aがコアロッド21およ
びダイ22間に入る。その後、図３に示すように、下降す
る上パンチ23が焼結体1Aを上から押してダイ22内に押し
込んでいく。これにより、図３（ａ）に示すように、焼
結体1Aの径大部7Aがダイ22の径大部28内に押し込まれ、
さらに、図３（ｂ）に示すように、焼結体1Aの径小部6A
の下側すなわち先端側がダイ22の径小部26内に押し込ま
れる。この押し込みにより、焼結体1Aの両端側がそれぞ
れ絞られて径方向内方へ変形し、コアロッド21に押し付
けられる。こうしてコアロッド21に押し付けられた部分
がそれぞれ軸受面３，４となる。図４は、焼結体1Aが両
パンチ23，24により軸方向にも圧縮されて加圧が完了し
た時点を示しているが、軸受面３，４は、焼結体1Aの径
小部6Aの先端側および径大部7Aに相当する部分にのみ形
成され、両軸受面３，４間においては、焼結体1Aの径小
部6Aにおける径大部7A側の部分がダイ22の径小部26内に
押し込まれないことにより、矯正された焼結体1Aすなわ
ち軸受１の内周面中間部２は軸受面３，４よりも内径が
大きくなる。その後、上パンチ24が上昇してダイ22から
抜けるとともに、下パンチ24が上昇して軸受１をコアロ
ッド21およびダイ22間から抜き出す。After the sintering step, the sintered body 1A is recompressed by a straightening press equipped with the straightening die and straightened into a predetermined shape. In this straightening process, the raised lower punch
After the sintered body 1A having the small diameter portion 6A on the lower side is loaded onto the 23, the lower punch 23 descends and the sintered body 1A enters between the core rod 21 and the die 22. After that, as shown in FIG. 3, the descending upper punch 23 pushes the sintered body 1A from above and pushes it into the die 22. As a result, the large diameter portion 7A of the sintered body 1A is pushed into the large diameter portion 28 of the die 22, as shown in FIG.
Further, as shown in FIG. 3B, the small diameter portion 6A of the sintered body 1A is
The lower side, that is, the tip side is pushed into the small diameter portion 26 of the die 22. By this pushing, both ends of the sintered body 1A are squeezed to be deformed inward in the radial direction and pressed against the core rod 21. Thus, the portions pressed against the core rod 21 become the bearing surfaces 3 and 4, respectively. FIG. 4 shows the time when the sintered body 1A is compressed in the axial direction by both punches 23 and 24 and the pressurization is completed. The bearing surfaces 3 and 4 are the small diameter portion 6A of the sintered body 1A. Is formed only on the front end side and the portion corresponding to the large-diameter portion 7A. Between the bearing surfaces 3 and 4, the portion of the small-diameter portion 6A of the sintered body 1A on the large-diameter portion 7A side has a small diameter Since it is not pushed into the portion 26, the corrected sintered body 1A, that is, the intermediate portion 2 of the inner peripheral surface of the bearing 1 has a larger inner diameter than the bearing surfaces 3 and 4. After that, the upper punch 24 rises to come out of the die 22, and the lower punch 24 comes up to take out the bearing 1 from between the core rod 21 and the die 22.
【００１６】なお、さらにその後、軸受１には潤滑油が
含浸される。After that, the bearing 1 is impregnated with lubricating oil.
【００１７】前記実施例の構成によれば、粉末成形工程
後、切削加工を行うことなく、矯正工程のみにより、軸
方向に分離して並んだ２つの軸受面３，４を有する軸受
１を製造でき、製造にかかるコストを低減できる。ま
た、両軸受面３，４部分がともにコイニングである矯正
工程において圧縮されて形成されるので、両軸受面３，
４部分の強度をともに高められるとともに、精度も高め
られる。しかも、第２の軸受面４に対応する径大部7A付
近は、粉末成形工程において段付きダイ12を用いている
ことにより密度が高くなるので、第２の軸受面４付近の
強度をいっそう高められる。従来のように、一方の軸受
面を粉末成形工程の段階で形成する場合とは異なり、焼
結体1Aと矯正用金型との間に大きな空間部が生じること
がないので、矯正に支障が生じることがない。According to the configuration of the above-described embodiment, the bearing 1 having the two bearing surfaces 3 and 4 which are separated and arranged in the axial direction is manufactured only by the straightening process without performing the cutting process after the powder molding process. Therefore, the manufacturing cost can be reduced. Further, since both bearing surfaces 3, 4 are formed by being compressed in the straightening process which is coining, both bearing surfaces 3, 4 are
The strength of the four parts can be increased and the accuracy can be improved. Moreover, since the density near the large diameter portion 7A corresponding to the second bearing surface 4 is increased by using the stepped die 12 in the powder molding process, the strength near the second bearing surface 4 is further increased. To be Unlike the conventional case where one bearing surface is formed at the stage of the powder molding process, there is no large space between the sintered body 1A and the straightening die, so there is no obstacle to straightening. It never happens.
【００１８】もちろん、従来のダブルベアリングと同
様、１つのコアロッド21で両軸受面３，４を形成するの
で、両軸受面３，４を正確に同軸にでき、高い精度を出
せる。また、両軸受面３，４間に軸に接しない部分があ
るので、摩擦抵抗が小さくなることにより、運転時の損
失を小さくできるとともに、長寿命化できる。Of course, like the conventional double bearing, since both bearing surfaces 3 and 4 are formed by one core rod 21, both bearing surfaces 3 and 4 can be accurately coaxial, and high precision can be obtained. Further, since there is a portion that does not contact the shaft between the bearing surfaces 3 and 4, the frictional resistance is reduced, so that the loss during operation can be reduced and the service life can be extended.
【００１９】なお、本発明は、前記実施例に限定される
ものではなく、種々の変形実施が可能である。例えば、
前記実施例では、矯正後の軸受１の外周面に径大部７が
残るようにしたが、圧粉体1Aの径大部7Aは、矯正により
外周面中間部５とほぼ同径になるまで絞ってもよい。ま
た、前記実施例では、矯正用金型のダイ22を内周面に３
つの段部30，31，32のあるものとしたが、両軸受面３，
４に相当する部分のみで圧粉体1Aを絞るために必須なの
は径小部26および径大部28であり、したがって、矯正用
金型のダイにおいて段部は最小限１つあればよい。It should be noted that the present invention is not limited to the above embodiment, and various modifications can be made. For example,
In the above-mentioned embodiment, the large diameter portion 7 is left on the outer peripheral surface of the bearing 1 after straightening, but the large diameter portion 7A of the green compact 1A becomes substantially the same diameter as the outer peripheral surface intermediate portion 5 by the straightening. You can squeeze it. Further, in the above-mentioned embodiment, the die 22 of the correction die is attached to the inner peripheral surface of the die 22.
Although there are two step portions 30, 31, 32, both bearing surfaces 3,
The small diameter portion 26 and the large diameter portion 28 are indispensable for squeezing the green compact 1A only at the portion corresponding to 4. Therefore, at least one step portion is required in the die of the straightening mold.
【００２０】また、前記実施例では、軸受面３，４の数
が２であったが、軸方向に分離して並んだ軸受面の数が
３以上の場合でも、本発明を適用できる。軸受面の数を
ｎとすると、図５に示すように、圧粉体41の外周面は、
少なくともｎ個の外径の異なる部分42，43，44が径の大
きさの順に軸方向に並んでいればよい。また、矯正用金
型のダイ51の内周面も、少なくともｎ個の内径の異なる
部分52，53，54が径の大きさの順に軸方向に並んでいれ
ばよい。そして、圧粉体41を焼結してなる焼結体41の各
部分42，43，44の外径が、ダイ51の各部分52，53，54の
内径よりもそれぞれ所定量大きく、かつ、加圧完了位置
を基準として、焼結体41の外周面の段部45，46とダイ51
の内周面の段部55，56とが交互にずれていればよい。こ
れにより、焼結体41が軸受面に相当する部分のみでコア
ロッド57に接するまで絞られ、軸受面間には内径のより
大きい部分が生じることになる。矯正工程後の軸受の外
周面には、少なくともｎ個の径の異なる部分が径の大き
さの順に軸方向に並んで生じる。Further, although the number of the bearing surfaces 3 and 4 is two in the above-mentioned embodiment, the present invention can be applied even when the number of the bearing surfaces arranged separately in the axial direction is three or more. Assuming that the number of bearing surfaces is n, as shown in FIG.
It suffices that at least n portions 42, 43, 44 having different outer diameters are arranged in the axial direction in the order of the size of the diameter. Further, on the inner peripheral surface of the die 51 of the orthodontic mold, at least n portions 52, 53, 54 having different inner diameters may be arranged in the axial direction in the order of the size of the diameter. The outer diameter of each part 42, 43, 44 of the sintered body 41 obtained by sintering the green compact 41 is larger than the inner diameter of each part 52, 53, 54 of the die 51 by a predetermined amount, and Steps 45 and 46 on the outer peripheral surface of the sintered body 41 and the die 51 are based on the pressurization completion position.
It suffices that the step portions 55 and 56 on the inner peripheral surface of are alternately displaced. As a result, the sintered body 41 is squeezed until it contacts the core rod 57 only at the portion corresponding to the bearing surface, and a portion having a larger inner diameter is formed between the bearing surfaces. On the outer peripheral surface of the bearing after the straightening step, at least n parts having different diameters are arranged in the axial direction in the order of the size of the diameter.
【００２１】[0021]
【発明の効果】本発明によれば、粉末冶金により、複数
の軸受面が軸方向に分離して並んでいる軸受を製造する
のに、粉末成形工程では、内径が全体的に均一であると
ともに、外径が一端側から他端側へ向けて段階的に大き
くなる筒状の圧粉体を成形し、矯正工程では、コアロッ
ドの外径が均一で、ダイの内径が一端側から他端側へ向
けて段階的に大きくなる矯正用金型を用い、前記複数の
軸受面に相当する部分のみで焼結体をダイにより径方向
内方へコアロッドに押し付けるまで変形させるので、矯
正に支障を生じることなく、切削加工を不要にでき、製
造にかかるコストを下げられる。また、全ての軸受面部
分が矯正工程において圧縮されて形成されるので、全て
の軸受面部分の強度を高められるとともに、精度も高め
られる。According to the present invention, by using powder metallurgy, a bearing having a plurality of bearing surfaces arranged side by side in the axial direction can be manufactured. In the straightening process, the outer diameter of the core rod is uniform, and the inner diameter of the die is from the one end to the other end. Using a straightening die that gradually increases in size, the sintered body is deformed until it is pressed radially inward by the die onto the core rod only at the portions corresponding to the plurality of bearing surfaces. Without the need for cutting, the cost of manufacturing can be reduced. Further, since all the bearing surface portions are compressed and formed in the straightening step, the strength of all the bearing surface portions can be enhanced and the accuracy can be enhanced.
【図１】本発明の軸受の製造方法の一実施例を示すもの
で、（ａ）は矯正後の軸受の断面図、（ｂ）は斜視図で
ある。1A and 1B show an embodiment of a method of manufacturing a bearing according to the present invention, in which FIG. 1A is a sectional view of the bearing after straightening, and FIG. 1B is a perspective view.
【図２】同上粉末成形時を示す断面図である。FIG. 2 is a cross-sectional view showing the above powder molding.
【図３】同上矯正時の途中の段階を示す断面図である。FIG. 3 is a cross-sectional view showing an intermediate stage during correction.
【図４】同上矯正時の加圧完了段階を示す断面図であ
る。FIG. 4 is a cross-sectional view showing a pressing completion stage at the time of correction.
【図５】本発明の軸受の製造方法の説明図である。FIG. 5 is an explanatory view of the bearing manufacturing method of the present invention.
１ 軸受 1A 圧粉体、焼結体 ３ 第１の軸受面 ４ 第２の軸受面 21 コアロッド 22 ダイ 23 下パンチ（パンチ） 24 上パンチ（パンチ） 41 圧粉体、焼結体 51 ダイ 57 コアロッド 1 bearing 1A green compact, sintered body 3 first bearing surface 4 second bearing surface 21 core rod 22 die 23 lower punch (punch) 24 upper punch (punch) 41 green compact, sintered body 51 die 57 core rod
Claims (1)
する粉末成形工程と、成形された圧粉体を加熱して焼結
する焼結工程と、焼結された焼結体を再圧縮して所定形
状に矯正する矯正工程とを備え、内径を小さくしてなる
複数の軸受面が軸方向に分離して並んでいる軸受の製造
方法において、 前記粉末成形工程では、内径が全体的に均一であるとと
もに、外径が一端側から他端側へ向けて段階的に大きく
なる筒状の圧粉体を成形し、 前記矯正工程では、軸受の内周面を形成するコアロッド
と、軸受の外周面を形成するダイと、軸受の端面を形成
するパンチとを備え、前記コアロッドの外径が均一で、
前記ダイの内径が一端側から他端側へ向けて段階的に大
きくなる矯正用金型を用い、前記複数の軸受面に相当す
る部分のみで焼結体を前記ダイにより径方向内方へコア
ロッドに押し付けるまで変形させることを特徴とする軸
受の製造方法。1. A powder molding step of compressing a raw material powder to form a cylindrical green compact, a sintering step of heating and sintering the green compact, and a sintered sintered body. In the method of manufacturing a bearing comprising a straightening step of re-compressing and straightening into a predetermined shape, and wherein a plurality of bearing surfaces each having a smaller inner diameter are arranged side by side in the axial direction, in the powder molding step, the inner diameter is Forming a cylindrical green compact that is uniform throughout and has an outer diameter gradually increasing from one end side to the other end side, and in the correcting step, a core rod that forms an inner peripheral surface of the bearing, A die for forming the outer peripheral surface of the bearing and a punch for forming the end surface of the bearing, and the outer diameter of the core rod is uniform,
Using a straightening die in which the inner diameter of the die gradually increases from one end side to the other end side, a sintered body is radially inwardly directed by the die to a core rod only at a portion corresponding to the plurality of bearing surfaces. A method of manufacturing a bearing, characterized in that the bearing is deformed until pressed.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24185995A JPH0988962A (en) | 1995-09-20 | 1995-09-20 | Manufacture of bearing |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP24185995A JPH0988962A (en) | 1995-09-20 | 1995-09-20 | Manufacture of bearing |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH0988962A true JPH0988962A (en) | 1997-03-31 |
Family
ID=17080584
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP24185995A Pending JPH0988962A (en) | 1995-09-20 | 1995-09-20 | Manufacture of bearing |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0988962A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7604304B2 (en) | 2001-08-22 | 2009-10-20 | Komatsu Ltd. | Crawler, crawler pin, crawler bush, and crawler manufacturing method |
| CN108907185A (en) * | 2018-08-09 | 2018-11-30 | 横店集团东磁股份有限公司 | Hard alloy moulding stamper |
-
1995
- 1995-09-20 JP JP24185995A patent/JPH0988962A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7604304B2 (en) | 2001-08-22 | 2009-10-20 | Komatsu Ltd. | Crawler, crawler pin, crawler bush, and crawler manufacturing method |
| CN108907185A (en) * | 2018-08-09 | 2018-11-30 | 横店集团东磁股份有限公司 | Hard alloy moulding stamper |
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