JP2004036745A - Sintered oil-bearing gear - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce noise from a sintered gear by setting an oil-bearing rate within a specified range according to the material of the sintered gear. <P>SOLUTION: This sintered gear is manufactured by using an iron sintered material with a Cu of less than 5 wt.% and an oil content of 21 to 25 vol.%, by using an iron copper sintered material with a Cu of 5 wt.% or higher and an oil content of 18 to 25vol.%, or bronze sintered material with an Sn of 9 to 11 wt.% and an oil content of 20 to 25 vol.%. Thus, not only a sufficient lubricity can be provided but also an excellent silentness, particularly, of low noise can be provided while maintaining a durability not so inferior to that of a conventional product. Accordingly, the gear can be widely used for such general purposes as in acoustic equipment and OA related equipment. <P>COPYRIGHT: (C)2004,JPO

Description

（単位：ｄＢｍ）
注１：サンプル１＝樹脂歯車
サンプル２＝汎用歯車（既成鉄製歯車）
サンプル３＝銅被覆鉄系焼結歯車（本発明品）
サンプル４＝錫添加焼結歯車（本発明品）
サンプル５＝亜鉛添加焼結歯車（本発明品）
注２：使用オイル
サンプル１：動粘度（４０℃）１００ｍｍ２／ｓに増粘剤を添加
サンプル２〜５：動粘度（４０℃）６８ｍｍ２／ｓ
【００１７】
上記のように、在来の樹脂製歯車（サンプル１）と、既成の鉄製歯車（サンプル２）と、本発明品である焼結歯車（サンプル３）、さらに本発明品である錫添加焼結歯車（サンプル４）、そして同じく本発明品である亜鉛添加焼結歯車（サンプル５）を用意し、それぞれの特性について試験したところ、サンプル１はサンプル３，４，５に比べ０〜４０００Ｈｚにおいて値は高くなっているが４０００〜６０００Ｈｚで低くなっている事により音が低く、聞こえにくくなり結果的に最も騒音が小さくなったが、歯車としての十分な強度と硬度を有しているとはいえず、汎用性の面において問題がある。
【００１８】
また、サンプル２は潤滑性は一応維持できているものの、最も騒音が大きくなり静粛性の面においては実用性に欠けることが解った。　しかしサンプル３では十分な潤滑性が維持できるばかりでなく、とくに静粛性の面において優れていることが解った。　またサンプル４およびサンプル５では、歯車としての強度と硬度および耐磨耗性をさらに向上させることができるとともに、十分な潤滑性と静粛性を維持できることが解った。
【００１９】
【発明の効果】
本発明の歯車は上記した通り、鉄系焼結材または鉄銅系焼結材、あるいは青銅焼結材を用いた歯車において、それぞれの歯車の含油率を各請求項に記載の通り一定の範囲内となるように設定したために、その何れもが従来品に比してそれ程劣らない耐久強度を維持しつつも、十分な潤滑性が得られるばかりでなく、特に静粛性に優れ、音響機器やＯＡ関連機器など、広範囲にわたる汎用性が可能となる。
【００２０】
さらに鉄系焼結材または鉄銅系焼結材、あるいは青銅焼結材の何れを問わず、Ｃｕ量に対し、一定量の錫や亜鉛を添加することにより歯車としての強度と硬度および耐磨耗性を高めることができる。　また、銅被覆鉄系焼結材を使用することにより表面が銅に覆われているため静粛性、耐食性、強度、耐摩耗性の効果を更に高めることができる。
【図面の簡単な説明】
【図１】本発明に係る歯車の一例をあらわした拡大縦断面図。
【符号の説明】
１　　　　ホイール
２　　　　歯車[0001]
[Industrial applications]
The present invention relates to the improvement of gears widely used as components of various devices ranging from various types of machinery and instruments to high-precision devices such as personal computers and printers, and has been known as a material that has been known for its excellent productivity and dimensional accuracy. An object of the present invention is to provide a further versatility by using a binding material and further having low noise characteristics.
[0002]
[Prior art]
Not only gears, but also engine parts such as sprockets and oil pump rotors, transmission parts such as synchronizer hubs and retainers, and various other transport equipment parts such as outboard motor pistons and electric bicycle parts. Various types of mechanical structural parts having a lubricating function by compacting and sintering a metal powder to form a sintered body and impregnating the sintered body with a machine oil or the like are already known. . Also, resin gears have been developed to achieve low noise.
[0003]
[Problems to be solved by the invention]
However, since these products are merely subjected to oil impregnation treatment on a sintered body manufactured according to the same standard as the manufacture of a general sintered machine part having no oil impregnating function, the upper limit of the oil content is at most 15%. % Stop. For this reason, although it has a certain degree of lubrication, it is not always sufficient, and there is a problem in terms of quietness.Therefore, depending on the field of mechanical parts used, for example, gears and motor bearings used as parts of audio equipment. May not be suitable for use. In addition, resin gears have the advantage of low cost, but are inferior in dimensional accuracy and cannot be used for high-performance products.Therefore, post-processing has been attempted to increase dimensional accuracy, The usage is limited because the cost is rather high.
[0004]
[Means for Solving the Problems]
Therefore, in the present invention, among the sintered metal parts, the characteristics of gears that require low noise and quietness, which can be used particularly for OA related equipment such as personal computers and printers, have been improved. More specifically, the invention of claim 1 relates to a sintered oil-impregnated gear using an iron-based sintered material of Cu: less than 5 (weight)% and having an oil content of 21 to 25 vol%. . Further, the invention of claim 2 relates to a sintered oil-impregnated gear using an iron-copper-based sintered material of Cu: 5 (weight)% or more and having an oil content of 18 to 25 vol%. In this case, personal computers and printers are increasingly used in ordinary households due to lower prices. In that case, it is natural that the balance between durability and quietness required for business use is different.
[0005]
Furthermore, the invention of claim 3 relates to the sintered oil-impregnated gear according to claim 2, wherein tin is added in an amount of 5 to 12 (weight)% based on the amount of Cu. Further, the invention of claim 4 relates to the sintered oil-impregnated gear according to claim 2, wherein zinc is added in an amount of 10 to 40 (weight)% based on the amount of Cu. Further, the invention of claim 5 relates to a sintered oil-impregnated gear using a bronze sintered material of Sn: 9 to 11 (weight)% and an oil content of 20 to 25 vol%.
Further, the invention of claim 6 relates to a sintered oil-impregnated gear according to any one of claims 1 to 5, wherein the contained Cu component is contained in the form of copper-coated iron powder.
In the configuration of the gear in each of the above cases, the durability required for the gear is maintained, and the oil content (oil content) is sufficient, so that not only lubrication properties but also particularly low noise properties are improved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the specific contents of the present invention will be described based on embodiments. FIG. 1 shows an example of a gear according to the present invention. That is, this gear represents a general involute spur gear, and has teeth 2 projecting outward on the outer peripheral surface of the cylindrical wheel 1 at regular intervals in the circumferential direction. As the material of the gear, various materials are selected depending on the application.
[0008]
In other words, in general, iron-based sintered materials when strength is prioritized, bronze sintered materials when quietness is prioritized, and when both strength and quietness are required Is a copper-coated iron-based sintered material. In addition, when any of these sintered materials is used, it is necessary to secure an oil content of a certain value or more in order to maintain lubricity.
[0009]
The oil content is related to the wear resistance and the life of the gear.If the oil content is low or too high, it is difficult not only to obtain good lubrication, but also to maintain quietness. As described above, it is necessary to set the oil content within an appropriate range depending on the gear material selected according to the purpose of use of the gear. In this case, the oil content can be set by adjusting the filling amount (weight) of the raw metal powder in the mold for molding the gear.
[0010]
Further, in the case of using an iron-based sintered material from the viewpoint of emphasizing strength as a material of the gear, not only the rigidity of the gear is maintained, but also a small amount of Cu is contained for the purpose of ensuring the quietness of the gear. Is preferred. However, if the content of Cu exceeds 5 (weight)%, a necessary and sufficient rigidity as a gear cannot be obtained. Therefore, an iron-based sintered material having a Cu content of less than 5% by weight is preferable, and it is difficult to maintain sufficient lubricity and quietness with an oil content of 20 vol% or less. However, on the other hand, if it exceeds 25 vol%, the rigidity of the gear is adversely affected, so that the oil content is desirably set within the range of 21 to 25 vol%.
[0011]
Sufficient quietness can be obtained even when using an iron-copper-based sintered material containing Cu: 5 (% by weight) or more to have both strength and quietness. In this case, since the surface hardness is low and the noise is low, the oil content can be suppressed somewhat lower than in the case where the iron-based sintered material of Cu: less than 5 (weight)% is used. If the ratio is less than 18 vol%, it is difficult to obtain sufficient lubricity as intended by the present invention. Conversely, if it exceeds 25 vol%, the rigidity of the gear is adversely affected, so that the oil content is 18 to 25 vol. It must be set so that it is within the range of%.
[0012]
Further, in this case, if tin or zinc is added to the above-mentioned Cu content, the strength, hardness and wear resistance of the gear can be increased. Specifically, in the case of adding tin, if the amount is less than 5 (% by weight) with respect to the amount of Cu, there is not much effect, and if it exceeds 12 (% by weight), the gear is too hard and brittle. Absent. Therefore, the amount of tin to be added to the amount of Cu is preferably in the range of 5 to 12 (weight)%.
[0013]
When zinc is added, if the amount is less than 10 (weight)% with respect to the amount of Cu, there is not much effect, and if it exceeds 40 (weight)%, strength as a gear is deteriorated, which is not preferable. Therefore, the amount of zinc to be added to the amount of Cu is preferably in the range of 10 to 40 (weight)%.
[0014]
Further, in the case where a bronze-based sintered material is used for giving priority to quietness, if Sn: less than 9 (weight)%, there is a problem that the strength is insufficient, and conversely, Sn: more than 11 (weight)%. It is desirable to set Sn in the range of 9 to 11 (weight)% because of the problem of becoming hard and brittle. If the oil content in this case is less than 20 vol%, sufficient lubricity is obtained. Is difficult, and even if it exceeds 25 vol%, there is a problem in strength. Therefore, the oil content in this case is preferably set in the range of 20 to 25 vol%.
[0015]
Except when using a bronze sintered material, when using an iron-based sintered material, the contained Cu component can also be contained in the form of copper-coated iron powder, thereby further improving quietness and corrosion resistance. You can also.
[0016]
【Example】
[Test data of various sample gears]

(Unit: dBm)
Note 1: Sample 1 = Resin gear sample 2 = General-purpose gear (pre-made iron gear)
Sample 3 = Copper-coated iron-based sintered gear (product of the present invention)
Sample 4 = tin-added sintered gear (product of the present invention)
Sample 5 = zinc-added sintered gear (product of the present invention)
Note 2: Oil sample 1: Kinematic viscosity (40 ° C.) 100 mm 2 / s with thickener added Samples 2-5: Kinematic viscosity (40 ° C.) 68 mm 2 / s
[0017]
As described above, the conventional resin gear (sample 1), the existing iron gear (sample 2), the sintered gear of the present invention (sample 3), and the tin-added sintered of the present invention A gear (sample 4) and a zinc-added sintered gear (sample 5), which is also a product of the present invention, were prepared and tested for their characteristics. As a result, the value of sample 1 was higher at 0 to 4000 Hz than that of samples 3, 4, and 5. Is higher but lower at 4000-6000 Hz, the sound is lower and hard to hear, resulting in the lowest noise, but it has sufficient strength and hardness as a gear However, there is a problem in versatility.
[0018]
In addition, although the lubricating property of Sample 2 could be maintained for the time being, the loudest noise was obtained and it was found that the sample 2 was not practical in terms of quietness. However, it was found that Sample 3 not only maintained sufficient lubricity, but was particularly excellent in quietness. In addition, it was found that in Samples 4 and 5, the strength, hardness and wear resistance of the gears could be further improved, and sufficient lubricity and quietness could be maintained.
[0019]
【The invention's effect】
As described above, the gear of the present invention is a gear using an iron-based sintered material or an iron-copper-based sintered material, or a bronze sintered material, and the oil content of each gear is in a certain range as described in each claim. Because they are set to be inside, not only can all obtain sufficient lubricity, but also particularly excellent in quietness, while maintaining the durability strength not so inferior to the conventional products, sound equipment and A wide range of versatility, such as OA-related equipment, is possible.
[0020]
Regardless of the iron-based sintered material, iron-copper-based sintered material, or bronze-sintered material, a certain amount of tin or zinc is added to the amount of Cu to obtain the strength, hardness and abrasion resistance of the gear. Wearability can be increased. Further, since the surface is covered with copper by using the copper-coated iron-based sintered material, the effects of quietness, corrosion resistance, strength, and abrasion resistance can be further enhanced.
[Brief description of the drawings]
FIG. 1 is an enlarged longitudinal sectional view illustrating an example of a gear according to the present invention.
[Explanation of symbols]
1 wheel 2 gear

Claims (6)

Cu: A sintered oil-impregnated gear using an iron-based sintered material of less than 5 (weight)% and having an oil content of 21 to 25% by volume. Cu: a sintered oil-impregnated gear using an iron-copper-based sintered material of 5 (weight)% or more and having an oil content of 18 to 25% by volume 3. The sintered oil-impregnated gear according to claim 2, wherein 5 to 12% (by weight) of tin is added to the amount of Cu. The sintered oil-impregnated gear according to claim 2, wherein zinc is added in an amount of 10 to 40 (weight)% based on the amount of Cu. Sn: A sintered oil-impregnated gear using a bronze sintered material of 9 to 11 (weight)% and an oil content of 20 to 25% by volume. The sintered oil-impregnated gear according to any one of claims 1 to 5, wherein the contained Cu component is contained in the form of copper-coated iron powder.

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