JP2004286130A - Power transmission component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power transmission component having well-balanced damping performance on natural vibration and other vibration propagated, and its manufacturing method for manufacturing the power transmission component in a relatively simple manner without complicating manufacturing processes and imposing excessive restrictions on manufacturing conditions. <P>SOLUTION: An annular gear part structural member 3 is mounted in a casting mold while securing a casting cavity inside, and metal melt is filled into the cavity to integrally form an annular trunk 5 inside the gear part structural member 3. Thus, in a boundary area between the gear part structural member 3 an the trunk 5, a gear part (the power transmission component) is produced in which a metallurgic joint portion mutually connecting these with metallurgic joint and a contact interface portion having no metallurgic joint exist. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００３１】
ギヤ単体では、実施例１の振動レベルは約９８ｄＢ（デシベル）であり、摩擦減衰リング７を使用した比較例２の振動レベル（約８６ｄＢ）に比べ劣るもののノーマル品である比較例１の振動レベル（１０８ｄＢ）よりも良好な結果を示した。また、実施例１の損失係数（０．４３９％）は比較例１（損失係数：０．２１２％）よりも良好であり、比較例２（損失係数：０．４５２％）とほぼ同等であった。このように実施例１のギヤは、振動レベル及び損失係数の総合評価において、比較例１に比べて優れた振動減衰性能を示した。
【００３２】
ギヤを動力伝達シャフトに装着した状態（俗にアッシー状態という）での振動減衰性能の測定は、図７に示すように、検査対象となるギヤを動力伝達シャフト１４に外嵌圧入し、シャフトの軸受け位置にて一対の定盤１５上に支持すると共に、そのシャフト１４の一端に加速度センサ１２を取り付け、各ギヤのギヤ部側面をハンマー１３でスラスト方向に加振した際に、加速度センサ１２が検知した振動を高速フーリエ変換装置（ＦＦＴ）及びパソコン（ＰＣ）で解析することにより行われた。一つのギヤにつき２０回測定を行い、その平均値を測定結果とした。図９（Ａ），（Ｂ）及び（Ｃ）はそのときの周波数解析の結果（平均値）を示し、下記表２は図９の周波数解析結果から判明したギヤアッシー状態振動での固有振動数（第１及び第２ピーク）並びにそれぞれの振動レベル及び損失係数を一覧にしたものである。
【００３３】
【表２】

【００３４】
ギヤアッシー状態では、二つの固有振動数ピークが観測された。第１ピークの固有振動数（４０００〜４３００Ｈｚ付近）における実施例１の振動レベル（約６６ｄＢ）は、比較例１（約７９ｄＢ）及び比較例２（約７７ｄＢ）よりも大幅に低減しており、損失係数についても実施例１（０．１７７％）は比較例１（０．０６２％）及び比較例２（０．０７８％）よりも良好である。又、第２ピークの固有振動数（４８００Ｈｚ前後）における実施例１の振動レベル（約５６ｄＢ）も、比較例１（約６４ｄＢ）及び比較例２（約６１ｄＢ）よりも大幅に低減しており、損失係数についても実施例１（０．９０７％）は比較例１（０．１９１％）及び比較例２（０．３２５％）よりも非常に良好である。即ちギヤを動力伝達シャフト１４に装着した状態では、振動レベル及び損失係数の両方において、実施例１のギヤは比較例１及び２のいずれよりも優れた振動減衰性能を示した。
【００３５】
さて、実施例１のギヤを、例えば車輌用トランスミッションのような機械システムの構成部品として使用する場合を考える。その際、ギヤ自体から放たれる騒音（即ち空気の疎密波として間接的に伝わる振動）がミッションケースを介してケース外部に伝達される可能性があるが、ケースを通過しようとする騒音の多くはケース自体によって減衰され、ケース外部に伝達される割合は極めて低く、実際上問題になることはない。他方、ギヤが装着されたシャフトを介してミッションケースに直接伝播される振動は、ケースを積極的に振動（又は共振）させてケースを騒音の発生源たらしめるので、実際上問題となることが多い。この点、実施例１のギヤによれば、ギヤ単体での振動減衰試験結果が示すようにギヤ単体でもある程度の騒音低減機能を有し、更には、ギヤアッシー状態での振動減衰試験結果が示すように、シャフト１４を介して伝播する振動を従来よりも飛躍的に低減することができる。
【００３６】
（実施例２）
実施例２は、上記実施例１における鋳型装着前のギヤ部構成部材３の円筒状内周面３１の表面に対し、図１０（Ａ）に示すように、ニッケルロウからなる界面形成促進層８を追加形成したものである。このとき使用したニッケルロウは、ギヤ部構成部材３を構成するＳＣＭ４２０相当のクロムモリブデン鋼、及び、胴部５を構成するＦＣ３００相当のねずみ鋳鉄よりも融点の低いＮｉ合金である。その後、実施例１と同様の鋳型装着及び鋳造の手順を経て、ギヤ部構成部材３の内側に胴部５が一体成形されたギヤを得た。
【００３７】
この実施例２のギヤを径方向に切断してその切断面の状態を観察したところ、ギヤ部構成部材３の円筒状内周面３１と、それに対応する胴部５の外周面との間には、ニッケルロウからなる界面形成促進層８を介在させた状態で、実施例１と同様、冶金的結合の無い界面が観察された。また、環状突条３２の周囲では、実施例１と同様、ギヤ部構成部材３側のクロムモリブデン鋼と胴部５側のねずみ鋳鉄との間に冶金的結合が観察された。尚、この実施例２のギヤを上述のような振動減衰試験にかけたところ、実施例１のギヤと同等の振動減衰性能を示した。
【００３８】
【発明の効果】
請求項１〜４に記載の動力伝達部品によれば、接触界面部における内外伝達部の各境界面（接触面）が、動力伝達部材の中心軸線方向（即ちスラスト方向）の振動を摩擦減衰させる摩擦減衰手段として機能することにより、固有振動もその他の伝播振動もバランス良く減衰可能となる。また、動力伝達部品の各部である外側伝達部と内側伝達部とは冶金的結合部を介して一体化されており、殊更に減衰リングのような付加物を追加する必要がない。
【００３９】
請求項５〜８に記載の動力伝達部品の製造方法によれば、環状の外側伝達部構成部材の内側に鋳包み的手法によって内側伝達部を簡便且つ確実に一体成形することができるのみならず、その内側伝達部と外側伝達部との境界領域に、冶金的結合部及び冶金的結合を持たない接触界面部を同時に形成することができる。また、本件製造方法は鋳包み的手法による一体成形であるので、外側伝達部構成部材に対する事前又は事後の加工（例えば鍛造、切削又は熱処理等）を自由に施すことができ、本件方法の採用が動力伝達部品の全製造過程におけるその他の加工工程において制約を課す原因にならないという長所がある。
【図面の簡単な説明】
【図１】上型、下型及び外側伝達部構成部材の径方向での断面図。
【図２】上下型間に外側伝達部構成部材を装着したときの断面図。
【図３】鋳造で得た動力伝達部品（実施例１）の径方向での断面図。
【図４】図３の一部を拡大して示す要部拡大断面図。
【図５】（Ａ）比較例１のギヤの径方向での断面図、（Ｂ）比較例２のギヤの径方向での断面図。
【図６】ギヤ単体での振動減衰性能試験方法の概略を示す図。
【図７】ギヤをシャフトに装着した状態（アッシー状態）での振動減衰性能試験方法の概略を示す図。
【図８】ギヤ単体での振動減衰性能試験における実施例１、比較例１及び比較例２の周波数解析結果（平均値）を示すグラフ。
【図９】ギヤシャフトアッシー状態での振動減衰性能試験における実施例１、比較例１及び比較例２の周波数解析結果（平均値）を示すグラフ。
【図１０】実施例２を示し、（Ａ）は鋳造前の要部断面図、（Ｂ）は鋳造後の要部断面図。
【符号の説明】
１…上型、２…下型（１及び２は鋳型を構成する）、３…ギヤ部構成部材（外側伝達部構成部材）、４…鋳造用キャビティ、５…胴部（内側伝達部）、８…界面形成促進層、３１…ギヤ部構成部材の円筒状内周面、３２…ギヤ部構成部材の環状突条、ｘ…中心軸線。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a power transmission component having a vibration damping function and a method for manufacturing the same.
[0002]
[Prior art]
Conventionally, a ring-shaped friction damping member (damping ring) is externally attached to a gear body, which is a kind of power transmission component, and a gear is formed based on the friction between the gear body and the damping ring and the friction between the multilayer wound damping members. There are known techniques for suppressing and reducing the vibration of a vehicle (for example, see Patent Documents 1 and 2). Also, there is a technology for suppressing and reducing gear vibration and meshing noise by integrally molding a vibration absorbing material (for example, a damping rubber or a synthetic resin) into the gear body (metal gear core) so as to be inseparable by insert molding. (See Patent Document 3).
[0003]
[Patent Document 1] Japanese Utility Model Laid-Open No. 7-12653 (abstract, effect of the invention)
[Patent Document 2] JP-A-2000-88053 (abstract, effect of the invention)
[Patent Document 3] JP-A-9-177943 (abstract)
[0004]
[Problems to be solved by the invention]
Vibrations generated by power transmission components such as gears are roughly classified into two types. One is a vibration in which the gear is largely displaced (specifically, resonance at a natural frequency), and the other is a vibration with a small displacement other than resonance (for example, a case such as a case transmitted through a shaft or the like from the gear). Vibration transmitted to other members).
[0005]
The external damping rings disclosed in Patent Documents 1 and 2 have a large effect on damping natural vibration causing resonance, but have a low effect on damping other small vibrations. For this reason, small vibrations may propagate from the gear body to the case and the like, and the case and the like may vibrate based on the small vibration and become a source of noise. In addition, since the damping ring, which is a separate member, is externally attached to the gear body, various additional processes such as forming a groove in the gear are required, which complicates the manufacturing process. Furthermore, if there is an addition to the gear body such as a damping ring, there is a problem that various problems to be solved in design such as securing an installation space therefor and avoiding interference with other members arise.
[0006]
Although the technology of Patent Document 3 has a large effect of reducing small vibrations that propagate to other members such as a shaft, the technology of Patent Document 3 relies only on the internal damping of a vibration absorber that is integrally molded. Was not enough. Also, when insert molding a vibration absorbing material into a gear body that has been subjected to heat treatment such as quenching, it is necessary to perform insert molding under conditions that can avoid inconvenience such as quenching due to heat during molding. However, there is a disadvantage that molding conditions are largely restricted.
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide a power transmission component capable of attenuating both natural vibration and other propagation vibrations in a well-balanced manner. Further, it is an object of the present invention to provide a method of manufacturing a power transmission component that can relatively easily manufacture such a power transmission component without complicating a manufacturing process and without imposing excessive restrictions on manufacturing conditions. It is in.
[0008]
[Means for Solving the Problems]
The first invention has an annular outer transmitting portion and an inner transmitting portion provided inside the outer transmitting portion, and the inner and outer transmitting portions are provided in a boundary region between the inner transmitting portion and the outer transmitting portion. A power transmission component characterized by the presence of a metallurgical connection interconnected by a metallurgical connection and a contact interface having no such metallurgical connection.
[0009]
According to the present invention, the annular outer transmitting portion and the inner inner transmitting portion are connected to each other via a metallurgical joint (joining site involving melting or diffusion of metal) existing in a boundary region between the two transmitting portions. By being connected and integrated, a single power transmission component is configured. At the contact interface existing in the boundary region between the two transmission parts, the boundary surface (contact surface) on the inner transmission part side and the boundary surface (contact surface) on the outer transmission part side contact each other in a non-bonded state, so that A solid-solid interface (solid-solid interface) is formed that does not metallurgically couple the transmission section. Each boundary surface (contact surface) of the inner and outer transmission portions at the contact interface portion constitutes a kind of friction damping means for frictionally damping the vibration of the power transmission member in the direction of the central axis (that is, the thrust direction). Efficiently attenuates the natural vibrations that cause it. In addition, by devising a combination of the metal forming the outer transmission portion and the metal forming the inner transmission portion, propagation vibrations other than the natural vibration can be effectively attenuated. As described above, according to the power transmission component of the present invention, the natural vibration and other propagation vibrations are attenuated in a well-balanced manner.
[0010]
The second invention is a method for manufacturing a power transmission component having an annular outer transmission portion and an inner transmission portion provided inside the outer transmission portion, wherein the annular outer transmission portion constituting member is mounted on a mold. A mounting step for securing a casting cavity inside the outer transmission section component; and a casting step for introducing a molten metal into the cavity to integrally mold the inner transmission section inside the outer transmission section component. A method for manufacturing a power transmission component, characterized in that:
[0011]
According to this manufacturing method, by guiding the molten metal to the cavity secured inside the annular outer transmission portion component member mounted on the mold, the inner transmission portion corresponding to the shape of the cavity is formed into the outer transmission portion component member. It is cast in an integrated state (that is, in a cast-in state). However, in the solidification process after the introduction of the molten metal, there is a difference in the degree of heat removal or heat retention depending on the distance from the molding surface of the mold in the boundary region where the outer transmission portion constituent member and the molten metal come into contact with each other. Has a significant effect on the mutual melting or mutual diffusion between the constituent metal of the outer transmission portion constituent member and the molten metal. Specifically, at a position relatively far from the molding surface of the mold, the surface of the outer transmission portion component is melted by the heat of the molten metal, and the outer transmission portion component and the molten metal are sufficiently melted in a molten state. Solidifies to form a metallurgical bond between the outer transmission component and the solidified metal (ie, the inner transmission). On the other hand, at the position near the molding surface of the mold, the heat of the molten metal easily escapes toward the mold, so that the heat of the molten metal does not sufficiently melt the surface of the outer transmission portion constituting member. The molten metal solidifies without melting the member and the molten metal, and a contact interface having no metallurgical bond is formed between the outer transmission portion constituting member and the solidified metal (that is, the inner transmission portion).
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
In this section, more preferred embodiments of the present invention and additional constituent elements are listed, and brief notes on them are added.
[0013]
The power transmission component of the present invention has an annular outer transmission portion and an inner transmission portion provided inside the outer transmission portion, and a boundary region between the inner transmission portion and the outer transmission portion has an inner transmission portion and an outer transmission portion. There are metallurgical connections that interconnect the parts by metallurgical bonds, and contact interfaces that do not have such metallurgical bonds. In such a power transmission component, it is preferable that the metal forming the inner transmission portion is a metal having higher vibration damping performance than the metal forming the outer transmission portion. In this way, by selecting a metal having a higher vibration damping performance than the constituent metal of the outer transmission part as the constituent metal of the inner transmission part, the propagation vibration transmitted from the power transmission part to other members connected thereto is selected. The damping performance is dramatically improved. As a combination of metals having a high propagation vibration damping effect, when the constituent metal of the outer transmission part is chromium molybdenum steel, cast iron (eg, gray cast iron or spheroidal graphite cast iron) is selected as the constituent metal of the inner transmission part. Can be exemplified.
[0014]
As a method of manufacturing a power transmission component in which a metallurgical joint and a contact interface can coexist in a boundary region between an inner transmission portion and an outer transmission portion, there are a cast-in casting method, a friction welding method, and a brazing method. Among these methods, the cast-in-place casting method is excellent in terms of controllability of forming a metallurgical joint and a contact interface inside a product and practicality. That is, when manufacturing a power transmission component having an annular outer transmission part and an inner transmission part provided inside the outer transmission part, the annular outer transmission part constituent member is mounted on a mold, and the outer transmission part constituent member is mounted. It is preferable to go through a mounting step of securing a casting cavity inside the inside and a casting step of introducing a molten metal into the cavity and integrally forming the inner transmission section inside the outer transmission section constituting member. At this time, it is preferable that the molten metal introduced into the cavity (the metal forming the inner transmission portion) is a metal having higher vibration damping performance than the metal forming the outer transmission portion forming member.
[0015]
When adopting the cast-in casting method, the annular outer transmitting portion constituting member mounted on the mold includes a cylindrical inner peripheral surface formed in the inner region thereof and an annular projecting member protruding from the cylindrical inner peripheral surface. It is preferable to have an article.
[0016]
When such a cylindrical inner peripheral surface and an annular outer transmitting portion constituting member having an annular ridge are used, an outer peripheral surface corresponding to the cylindrical inner peripheral surface of the outer transmitting portion constituting member is provided in the cavity of the mold. An inner transmission portion having an annular groove corresponding to the annular ridge of the outer transmission portion component is cast. When the molten metal is introduced into the cavity, the annular ridge is effectively heated by the molten metal filled around the annular ridge, so that the surface of the annular ridge is melted and the metal melts with the molten metal. Or, mutual diffusion is promoted. As a result, a metallurgical connection is reliably formed between the annular ridge of the outer transmission portion constituent member and the annular groove of the inner transmission portion. On the other hand, on the cylindrical inner peripheral surface (the portion other than the annular ridge) of the outer transmission portion component member, even when heat is supplied from the molten metal, heat is easily released to the main body and the mold of the outer transmission portion component member. The cylindrical inner peripheral surface is not sufficiently melted, and the metal is not melted or diffused so much with the molten metal. As a result, the molten metal solidifies while the cylindrical inner peripheral surface and the molten metal are not melted, and the gap between the cylindrical inner peripheral surface of the outer transmitting portion constituting member and the outer peripheral surface of the inner transmitting portion (solidified metal). In this case, a contact interface having no metallurgical bond as described above is formed.
[0017]
Further, in adopting a cast-in casting method, before the mounting step, an annular outer surface having a cylindrical inner peripheral surface formed in the inner region and an annular ridge protruding from the cylindrical inner peripheral surface. While preparing the transmitting portion constituent member, an interface formation promoting layer made of a metal having a lower melting point than any of the constituent metal of the outer transmitting portion forming member and the constituent metal of the inner transmitting portion is formed on the cylindrical inner peripheral surface. It is preferable to further include a step.
[0018]
When such a cylindrical inner peripheral surface and an annular outer transmitting portion constituting member having an annular ridge are used, an outer peripheral surface corresponding to the cylindrical inner peripheral surface of the outer transmitting portion constituting member is provided in the cavity of the mold. An inner transmission portion having an annular groove corresponding to the annular ridge of the outer transmission portion component is cast. When the molten metal is introduced into the cavity, the annular ridge is effectively heated by the molten metal filled around the annular ridge, so that the surface of the annular ridge is melted and the metal melts with the molten metal. Or, mutual diffusion is promoted. As a result, a metallurgical connection is reliably formed between the annular ridge of the outer transmission portion constituent member and the annular groove of the inner transmission portion. On the other hand, on the cylindrical inner peripheral surface (the portion other than the annular ridge) of the outer transmission portion component member, even when heat is supplied from the molten metal, heat is easily released to the main body and the mold of the outer transmission portion component member. The cylindrical inner peripheral surface does not melt sufficiently. In addition, the interface metal is formed between the outer transmission part component member, the inner transmission part metal (that is, the molten metal), and the interface formation promoting layer interposed between the two transmission parts. Even when the melting point of the constituent metal of the layer is the lowest and the molten metal starts to solidify, the interface formation promoting layer melted by the heat of the molten metal maintains the molten state. Therefore, when the molten metal solidifies and contracts, the interface formation accelerating layer in the molten state serves as a kind of lubricant, and the outer peripheral surface of the inner transmission portion obtained by solidifying the molten metal and The formation of a clear solid-solid interface with the cylindrical inner peripheral surface of the transmission member is promoted.
[0019]
In this way, the molten metal solidifies without melting the cylindrical inner peripheral surface of the outer transmission portion component and the molten metal, and the outer peripheral surface of the cylindrical inner peripheral surface of the outer transmission portion component and the inner transmission portion (solidified metal). A contact interface having no metallurgical bond as described above is formed between the surfaces. The advantage of previously forming an interface formation promoting layer made of a low melting point metal on the cylindrical inner peripheral surface of the outer transmission portion constituting member before mounting the mold is that the formation of the solid-solid interface in the solidification process of the molten metal is more. In addition to clarity, the point is that the position selectivity or position controllability when forming a contact interface having no metallurgical bond is improved.
[0020]
In addition, when the constituent metal of the outer transmission part constituent member is chromium molybdenum steel and the constituent metal of the inner transmission part is cast iron (for example, gray cast iron or spheroidal graphite cast iron), as the constituent metal of the interface formation promoting layer, for example, Nickel brazing (Ni alloy) can be exemplified.
[0021]
【Example】
Embodiments 1 and 2 in which the present invention is embodied in a gear (intermediate product) as a power transmission component, and Comparative Examples 1 and 2 belonging to the category of the conventional example will be described.
[0022]
(Example 1)
First, as shown in FIG. 1, a gear component 3 as an annular outer transmission component is prepared. The gear component member 3 is obtained by forging and cutting a chromium molybdenum steel material equivalent to SCM420, and has a cylindrical inner peripheral surface 31 formed in an inner region to surround the central axis x. And an annular ridge 32 projecting from the center position of the cylindrical inner peripheral surface 31. The cylindrical inner peripheral surface 31 extends in the direction of the central axis x, and the annular ridge 32 projects toward the central axis x in a direction orthogonal to the central axis x.
[0023]
As shown in FIG. 2, the gear component 3 was set in a mold composed of an upper mold 1 and a lower mold 2, and an annular casting cavity 4 was secured inside the gear component 3. The upper mold 1 and the lower mold 2 have shapes as shown in FIG. 1, and are both made of carbon dioxide hardened sand. Then, the molten cast iron was introduced into the cavity 4 from the upper mold pouring port 1a (that is, gravity casting). At this time, the cast iron molten metal is melted using a high-frequency induction furnace for melting to melt the gray cast iron (FC) or spheroidal graphite cast iron (FCD) reverting material and steel chips at normal pressure, and into it, a carburizing agent and 0.3 wt. Wt.% Fe-75% Si inoculant was added and melted. The final component composition was C: 3.04%, Si: 2.08%, Mn: 0.63%, P: It is a gray cast iron melt equivalent to FC300, which has 0.028% and S: 0.087%.
[0024]
After the pouring is completed, the molten cast iron in the cavity 4 solidifies after a predetermined time has elapsed, and a gear is integrally formed with the annular body 5 as an inner transmission portion made of gray cast iron inside the gear component 3. Was. The gear immediately after the completion of the casting is an intermediate product, and becomes a final product gear by performing post-processing such as forming gear teeth on the outer peripheral portion of the gear portion constituting member 3.
[0025]
FIG. 3 schematically shows a gear obtained by casting cut in a radial direction, and FIG. 4 shows a state in which a part of FIG. 3 (a boundary region between the gear component 3 and the body 5) is enlarged. . Before casting, the annular ridge 32 of the gear component member 3 was angular (see FIG. 1), but after casting, it was melted by the heat of the molten cast iron so that the corners became round and were completely cast in the body 5. Was wrapped around. In addition, around the annular ridge 32 (boundary area shown by the broken line in FIG. 4), the chromium molybdenum steel on the gear part component member 3 and the gray cast iron on the body part 5 mutually melt or diffuse to form different types. A state in which the boundary between the metals was unknown, that is, a metallurgical bond between the two was observed. On the other hand, in the vicinity of the inner peripheral surface 31 of the gear component member located before and after the root of the annular ridge 32 (boundary area shown by a solid line in FIG. 4), the chrome molybdenum steel on the gear component component 3 side and the body 5 side A state in which the boundary with the gray cast iron was clear, that is, an interface having no metallurgical bond was observed.
[0026]
(Comparative Example 1)
The gear of Comparative Example 1 shown in FIG. 5 (A) is formed by forging and cutting a chromium molybdenum steel material equivalent to SCM420 to have the same shape as the gear of Example 1. In this gear, there is no distinction between a body part and a gear part, and the whole is made of a single chromium molybdenum steel. The gear 6 of Comparative Example 1 is a normal product that has not been subjected to any special vibration damping measures.
[0027]
(Comparative Example 2)
The gear of Comparative Example 2 shown in FIG. 5B is obtained by adding an annular friction damping ring 7 to the gear 6 made of chromium molybdenum steel of Comparative Example 1 described above. This friction damping ring 7 is made of gray cast iron equivalent to FC150, and is fixed inside the gear 6 like a snap ring based on the expanding force of the ring 7.
[0028]
(Evaluation of vibration damping performance of Example 1, Comparative Example 1 and Comparative Example 2)
With respect to the above three gears, the vibration damping performance of the gear alone and the vibration damping performance in a state of being mounted on the power transmission shaft were evaluated.
[0029]
As shown in FIG. 6, the measurement of the vibration damping performance of the gear alone is performed by placing the gear to be inspected on the cushioning material 11 and mounting the acceleration sensor 12 on the side of the gear, and the gear opposite to the sensor position. This was performed by analyzing the vibration detected by the acceleration sensor 12 when the side face was vibrated by the hammer 13 using a fast Fourier transform device (FFT) and a personal computer (PC). The measurement was performed 20 times for one gear, and the average value was used as the measurement result. 8 (A), 8 (B) and 8 (C) show the results (average value) of the frequency analysis at that time. Table 1 below shows the natural frequency of the gear single vibration found from the frequency analysis result of FIG. It is a list of vibration levels and loss factors. The loss coefficient is an index indicating the degree of vibration damping, and the larger the number, the higher the damping performance.
[0030]
[Table 1]

[0031]
With the gear alone, the vibration level of Example 1 was about 98 dB (decibel), which was inferior to the vibration level of Comparative Example 2 using the friction damping ring 7 (about 86 dB), but the vibration level of Comparative Example 1 which was a normal product. (108 dB). Further, the loss coefficient of Example 1 (0.439%) was better than that of Comparative Example 1 (loss coefficient: 0.212%), and was almost equivalent to that of Comparative Example 2 (loss coefficient: 0.452%). Was. Thus, the gear of Example 1 exhibited superior vibration damping performance as compared with Comparative Example 1 in the comprehensive evaluation of the vibration level and the loss coefficient.
[0032]
As shown in FIG. 7, the measurement of the vibration damping performance in a state in which the gear is mounted on the power transmission shaft (commonly referred to as an assembly state) is performed by externally fitting the gear to be inspected into the power transmission shaft 14 and pressing the shaft. At the bearing position, it is supported on a pair of bases 15, and an acceleration sensor 12 is attached to one end of the shaft 14. When the gear side surface of each gear is vibrated in the thrust direction by a hammer 13, the acceleration sensor 12 This was performed by analyzing the detected vibration with a fast Fourier transform device (FFT) and a personal computer (PC). The measurement was performed 20 times for one gear, and the average value was used as the measurement result. 9 (A), 9 (B) and 9 (C) show the results (average value) of the frequency analysis at that time, and Table 2 below shows the natural frequency (gear assembly state vibration) found from the frequency analysis result of FIG. (First and second peaks) and their respective vibration levels and loss factors.
[0033]
[Table 2]

[0034]
In the gear assembly state, two natural frequency peaks were observed. The vibration level (about 66 dB) of Example 1 at the natural frequency of the first peak (around 4000 to 4300 Hz) is significantly lower than that of Comparative Example 1 (about 79 dB) and Comparative Example 2 (about 77 dB). The loss coefficient of Example 1 (0.177%) is also better than Comparative Example 1 (0.062%) and Comparative Example 2 (0.078%). In addition, the vibration level (about 56 dB) of Example 1 at the natural frequency of the second peak (about 4800 Hz) is also significantly lower than that of Comparative Example 1 (about 64 dB) and Comparative Example 2 (about 61 dB). The loss coefficient of Example 1 (0.907%) is much better than Comparative Example 1 (0.191%) and Comparative Example 2 (0.325%). That is, when the gear was mounted on the power transmission shaft 14, the gear of Example 1 exhibited better vibration damping performance than both Comparative Examples 1 and 2 in both the vibration level and the loss coefficient.
[0035]
Now, consider the case where the gear of the first embodiment is used as a component of a mechanical system such as a vehicle transmission. At this time, noise emitted from the gear itself (that is, vibration indirectly transmitted as compressional waves of air) may be transmitted to the outside of the case via the transmission case, but most of the noise that tries to pass through the case. Is attenuated by the case itself and the rate of transmission to the outside of the case is extremely low and does not pose a practical problem. On the other hand, vibrations that are directly transmitted to the transmission case via the shaft on which the gears are mounted can vibrate (or resonate) the case positively and cause the case to be a source of noise. Many. In this regard, according to the gear of the first embodiment, the gear alone has a certain level of noise reduction function as shown by the vibration attenuation test result of the gear alone, and furthermore, the gear attenuation state shows the result of the vibration attenuation test in the gear assembled state. In addition, vibration propagating through the shaft 14 can be drastically reduced as compared with the related art.
[0036]
(Example 2)
In the second embodiment, as shown in FIG. 10A, the interface formation promoting layer 8 made of nickel brazing is applied to the surface of the cylindrical inner peripheral surface 31 of the gear component member 3 before the casting of the mold in the first embodiment. Is additionally formed. The nickel brazing used at this time is a chromium molybdenum steel equivalent to SCM420 constituting the gear part constituting member 3 and a Ni alloy having a lower melting point than gray cast iron equivalent to FC300 constituting the body part 5. Thereafter, through the same procedure of casting and casting the mold as in Example 1, a gear in which the body 5 was integrally formed inside the gear component 3 was obtained.
[0037]
When the gear of Example 2 was cut in the radial direction and the state of the cut surface was observed, the gear between the cylindrical inner peripheral surface 31 of the gear component member 3 and the corresponding outer peripheral surface of the body 5 was observed. As in Example 1, an interface having no metallurgical bond was observed with the interface formation accelerating layer 8 made of nickel brazing interposed therebetween. Further, as in Example 1, metallurgical bonding was observed between the chromium molybdenum steel on the gear component member 3 side and the gray cast iron on the body 5 side around the annular ridge 32. When the gear of Example 2 was subjected to the vibration damping test as described above, it showed the same vibration damping performance as the gear of Example 1.
[0038]
【The invention's effect】
According to the power transmission component described in claims 1 to 4, each boundary surface (contact surface) of the inner and outer transmission portions at the contact interface portion frictionally attenuates vibration in the center axis direction (that is, the thrust direction) of the power transmission member. By functioning as the friction damping means, it is possible to attenuate the natural vibration and other propagation vibrations in a well-balanced manner. In addition, the outer transmission portion and the inner transmission portion, which are the components of the power transmission component, are integrated via a metallurgical joint, and there is no need to add an additional component such as a damping ring.
[0039]
According to the method for manufacturing a power transmission component according to claims 5 to 8, not only can the inner transmission portion be easily and reliably integrally formed inside the annular outer transmission portion component member by a cast-in method. In the boundary region between the inner transmission portion and the outer transmission portion, a metallurgical joint and a contact interface having no metallurgical joint can be simultaneously formed. In addition, since the present manufacturing method is an integral molding by a cast-in method, it is possible to freely perform pre- or post-processing (for example, forging, cutting, heat treatment, etc.) on the outer transmission portion constituting member. It has the advantage that it does not impose any restrictions on other processing steps in the entire manufacturing process of the power transmission component.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an upper die, a lower die, and an outer transmission portion constituting member in a radial direction.
FIG. 2 is a cross-sectional view when an outer transmission portion component member is mounted between upper and lower dies.
FIG. 3 is a sectional view in the radial direction of a power transmission component (Example 1) obtained by casting.
FIG. 4 is an enlarged sectional view of a main part showing a part of FIG. 3 in an enlarged manner.
5A is a sectional view of a gear of Comparative Example 1 in a radial direction, and FIG. 5B is a sectional view of a gear of Comparative Example 2 in a radial direction.
FIG. 6 is a diagram schematically illustrating a method of testing a vibration damping performance of a single gear.
FIG. 7 is a diagram schematically illustrating a vibration damping performance test method in a state in which a gear is mounted on a shaft (assy state).
FIG. 8 is a graph showing frequency analysis results (average value) of Example 1, Comparative Example 1, and Comparative Example 2 in a vibration damping performance test using a single gear.
FIG. 9 is a graph showing frequency analysis results (average values) of Example 1, Comparative Example 1, and Comparative Example 2 in a vibration damping performance test in a gear shaft assembly state.
10A and 10B show a second embodiment, in which FIG. 10A is a cross-sectional view of main parts before casting, and FIG. 10B is a cross-sectional view of main parts after casting.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Upper mold, 2 ... Lower mold (1 and 2 constitute a casting mold), 3 ... Gear part constituent member (outer transmission part constituent member), 4 ... Casting cavity, 5 ... Trunk part (inner transmission part), 8: Interface formation accelerating layer, 31: Cylindrical inner peripheral surface of the gear component, 32: Annular ridge of the gear component, x: Central axis.

Claims (8)

It has an annular outer transmission part and an inner transmission part provided inside the outer transmission part. In the boundary area between the inner transmission part and the outer transmission part, the inner and outer transmission parts are interconnected by metallurgical coupling. A power transmission component characterized by the presence of a metallurgical connection that forms a contact and a contact interface that does not have such a metallurgical connection. The power transmission component according to claim 1, wherein the metal forming the inner transmission portion is a metal having higher vibration damping performance than the metal forming the outer transmission portion. The annular outer transmission portion has a cylindrical inner peripheral surface formed in an inner region thereof and an annular ridge protruding from the cylindrical inner peripheral surface, and the inner transmission portion includes the outer transmission member. An outer peripheral surface corresponding to the cylindrical inner peripheral surface of the portion, and an annular groove corresponding to the annular ridge of the outer transmission portion,
The metallurgical joint is formed between the annular ridge of the outer transmission portion and the annular groove of the inner transmission portion, and between the cylindrical inner peripheral surface of the outer transmission portion and the outer peripheral surface of the inner transmission portion. The power transmission component according to claim 1 or 2, wherein the contact interface is formed in (1). 4. The contact interface according to claim 1, wherein an interface formation promoting layer made of a metal having a lower melting point than any of the constituent metal of the inner transmitting part and the constituent metal of the outer transmitting part is present. A power transmission component as described in Crab. A method for manufacturing a power transmission component having an annular outer transmission portion and an inner transmission portion provided inside the outer transmission portion,
A mounting step of mounting the annular outer transmission section component on the mold and securing a casting cavity inside the outer transmission section component,
A casting step of introducing a molten metal into the cavity and integrally molding the inner transmission part inside the outer transmission part constituent member. The method for manufacturing a power transmission component according to claim 5, wherein the molten metal introduced into the cavity is a metal having a higher vibration damping performance than a metal constituting the outer transmission portion constituting member. The annular outer transmission portion constituting member has a cylindrical inner peripheral surface formed in an inner region thereof, and an annular ridge protruding from the cylindrical inner peripheral surface. Item 7. The method for manufacturing a power transmission component according to item 5 or 6. Prepare an annular outer transmission portion constituting member having a cylindrical inner peripheral surface formed in the inner region and an annular ridge protruding from the cylindrical inner peripheral surface, and, on the cylindrical inner peripheral surface, The motive power according to claim 5 or 6, further comprising a step of forming an interface formation accelerating layer made of a metal having a lower melting point than any of the constituent metal of the outer transmission part constituent member and the constituent metal of the inner transmission part. Manufacturing method of transmission parts.

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