JPH01138949A - Sound attenuating device for rotary electric machine - Google Patents
Sound attenuating device for rotary electric machineInfo
- Publication number
- JPH01138949A JPH01138949A JP13181987A JP13181987A JPH01138949A JP H01138949 A JPH01138949 A JP H01138949A JP 13181987 A JP13181987 A JP 13181987A JP 13181987 A JP13181987 A JP 13181987A JP H01138949 A JPH01138949 A JP H01138949A
- Authority
- JP
- Japan
- Prior art keywords
- air
- wavelength
- electric machine
- cooling fan
- rotary electric
- 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
- 238000001816 cooling Methods 0.000 claims abstract description 25
- 230000002093 peripheral effect Effects 0.000 claims abstract description 7
- 230000000644 propagated effect Effects 0.000 claims 1
- 238000000034 method Methods 0.000 abstract 2
- 230000005611 electricity Effects 0.000 abstract 1
- 230000000694 effects Effects 0.000 description 20
- 230000002238 attenuated effect Effects 0.000 description 5
- 230000000737 periodic effect Effects 0.000 description 4
- 239000011490 mineral wool Substances 0.000 description 3
- 239000011491 glass wool Substances 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 239000011358 absorbing material Substances 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 230000004323 axial length Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
Abstract
Description
【発明の詳細な説明】
［発明の目的］
（産業上の利用分野）
本発明は、冷却ファンを覆うファンカバーから漏れ出る
騒音を低減するようにした回転電機に関する。DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a rotating electrical machine that reduces noise leaking from a fan cover that covers a cooling fan.
（従来の技術）
従来より、回転電機本体の外部に突出する回転軸に冷却
ファンを取着すると共に、この冷却ファンにより生成し
た風を前記回転電機本体の外周部に導くためのファンカ
バーを前記回転電機本体に取着した構成の回転電機があ
る。このものにおいては、ファンカバーから漏れ出る騒
音を低減するために、例えば実開昭５５−１６６１６０
号公報が知られている。この公報には第５図に示すよう
に導風カバー５の内面に、多孔質プラスチック、グラス
ウール、フェルトロックウール等から成る吸音部材を取
着したものがあった。(Prior Art) Conventionally, a cooling fan is attached to a rotating shaft protruding outside of a main body of a rotating electric machine, and a fan cover for guiding the wind generated by the cooling fan to the outer peripheral part of the main body of the rotating electric machine is provided. There is a rotating electrical machine that is attached to the main body of the rotating electrical machine. In this case, in order to reduce the noise leaking from the fan cover, for example,
No. Publication is known. In this publication, as shown in FIG. 5, a sound absorbing member made of porous plastic, glass wool, felt rock wool, etc. is attached to the inner surface of the air guide cover 5.
（発明が解決しようとする問題点）
しかしながら、単に吸音部材を設けただけでは、第４図
（ａ）に示すように中周波数帯域から高周波数帯域の騒
音に対してはある程度の減音効果が期待できるが、低周
波数帯域の騒音に対してはほとんど減音効果がない。と
ころが、騒音の主成分は冷却ファンの回転によるファン
騒音であり、このファン騒音の基本周波数（最低周波数
）は冷却ファンの羽根枚数と単位時間当りの回転数との
積に相当する周波数（一般に５００Ｈｚ以下）になって
低周波数帯域に属するから、上述した吸音部材だけにた
よっては、低周波数帯域のファン騒音をほとんど低減す
ることができず、全体として十分な低騒音化を達成する
ことができなかった。(Problems to be Solved by the Invention) However, simply providing a sound absorbing member does not have a certain degree of sound reduction effect on noise from the medium frequency band to the high frequency band, as shown in Figure 4(a). Although this is promising, it has almost no effect in reducing noise in the low frequency band. However, the main component of the noise is fan noise caused by the rotation of the cooling fan, and the fundamental frequency (lowest frequency) of this fan noise is the frequency (generally 500Hz) corresponding to the product of the number of blades of the cooling fan and the number of rotations per unit time. (below) and belongs to the low frequency band. Therefore, relying only on the sound absorbing member described above will hardly reduce the fan noise in the low frequency band, and it will not be possible to achieve sufficient noise reduction as a whole. There wasn't.
また、ファンカバーの軸方向長さもファン騒音に影響す
ることも明確にされておらず、逆効果に及ぶこともあり
、全体として十分な低騒音化を達成することができなか
った。Furthermore, it is not clear that the axial length of the fan cover also affects fan noise, and this may have the opposite effect, making it impossible to achieve sufficient noise reduction as a whole.
本発明はこのような問題点を解決しようとするもので、
従ってその目的は、低周波数帯域の騒音を十分に低減で
きる回転電機を提供するにある。The present invention aims to solve these problems,
Therefore, the objective is to provide a rotating electric machine that can sufficiently reduce noise in the low frequency band.
［発明の構成］
（問題点を解決するための手段）
本発明は、冷却ファンを覆うファンカバーに、その内部
を伝播する所定の周波数を外す波長の１／４波長の奇数
倍の長さを有するものと、前記所定の周波数の波長の１
／８波長の奇数倍の長さを有するものとを組合せた膨張
箱部を設けたことを特徴とするものである。[Structure of the Invention] (Means for Solving the Problems) The present invention provides a fan cover that covers a cooling fan with a length that is an odd number multiple of a quarter wavelength of a wavelength that excludes a predetermined frequency that propagates inside the fan cover. and one wavelength of said predetermined frequency.
The present invention is characterized in that an expansion box portion having a length that is an odd number multiple of /8 wavelength is provided.
（作 用）
所定周波数の音波が例えば、ファン騒音の基本周波数が
羽根枚数と単位時間当りの回転数との積に相当する周波
数になることに着目して、管路の一部を急膨張、又は、
急収縮させることによって音を干渉させ減音させるもの
である。この減音の周波数特性は、管路の長さｇが短い
ほど、緩慢な周期的変化が得られる。この発明の狙いは
、管路の長さｇが、ファン騒音の基本周波数の音波の波
長の１／４波長の奇数倍のときに最大の減音効果を示す
。この減音効果を第３図（ａ）に示す。(Function) Focusing on the fact that a sound wave of a predetermined frequency has a frequency corresponding to the fundamental frequency of fan noise, which is the product of the number of blades and the number of rotations per unit time, a part of the pipe is rapidly expanded. Or
By rapidly contracting, it interferes with the sound and reduces the sound. As for the frequency characteristics of this sound reduction, the shorter the length g of the pipe, the slower the periodic change can be obtained. The aim of the present invention is to exhibit the maximum sound reduction effect when the length g of the pipe is an odd multiple of 1/4 wavelength of the wavelength of the sound wave at the fundamental frequency of the fan noise. This sound reduction effect is shown in FIG. 3(a).
しかし、波長の１／４波長の偶数倍のときは最少の減音
を示すことになる。ここでは、７２０Ｈｚ。However, when the wavelength is an even number multiple of 1/4 wavelength, the minimum sound attenuation is exhibited. Here, it is 720Hz.
１４４０Ｈｚが最少となっている。そこでこの最少の減
音を示すところを補う点で波長の１／８波長の奇数倍の
長さに管路の長さｇ″を設けることにより、第３図（ｂ
）に示す減音効果が加わり全体としては第３図（ｃ）に
示す減音効果が得られ全体の減音効果として周期的変化
のない減音特性が得られる。1440Hz is the minimum. Therefore, in order to compensate for this minimum sound reduction, the length g'' of the conduit is set at an odd number multiple of 1/8 of the wavelength, as shown in Fig. 3 (b).
) is added, and the overall sound reduction effect shown in FIG. 3(c) is obtained, and the overall sound reduction effect is a sound reduction characteristic without periodic changes.
尚、上記説明ではファン騒音について述べたが、発生周
波数は限定しない。Incidentally, although the above description describes fan noise, the generation frequency is not limited.
（実施例） 以下、本発明の第１実施例を第１図に基いて説明する。(Example) A first embodiment of the present invention will be described below with reference to FIG.
１は回転電機本体で、その外周部に冷却ファン２を多数
形成すると共に、外部に突出する回転軸３の一端部冷却
フアン４を取着している。５は冷却ファン４を覆うよう
に回転電機本体１に取着した導風カバーで、これの内部
には、冷却ファン４と対向するように保護網６を配置し
、この保護網６によって導風カバー５の内部を吸気室７
と送風室８とに区分している。そして、吸気室７には吸
気ロアａを形成し、一方、送風室８の外周側部分と回転
電機本体１との間には、吹出口８ａを形成し、この吹出
口８ａから回転電機本体１の外周部に送風するようにし
ている。Reference numeral 1 denotes a rotating electric machine main body, on the outer periphery of which a number of cooling fans 2 are formed, and a cooling fan 4 is attached to one end of a rotary shaft 3 that projects outside. Reference numeral 5 denotes an air guide cover attached to the rotating electric machine main body 1 so as to cover the cooling fan 4. A protective net 6 is arranged inside this so as to face the cooling fan 4, and the air guide cover 5 is provided so as to cover the cooling fan 4. The inside of the cover 5 is connected to the intake chamber 7.
and a ventilation chamber 8. An intake lower a is formed in the intake chamber 7, and an air outlet 8a is formed between the outer peripheral side of the air blowing chamber 8 and the rotating electrical machine main body 1. Air is blown to the outer periphery of the
そして、９は導風カバー５に設けた膨張箱部で、尾管１
０を介して前記吸気ロアａと連通している。9 is an expansion box part provided on the wind guide cover 5, and the tail pipe 1
0 and communicates with the intake lower a.
１１は尾管１０に対応して設けた入口管である。11 is an inlet pipe provided corresponding to the tail pipe 10.
ｐｌは前記膨張箱部９の外周長さで、ｆＩ２は内周長さ
である。また、ファンカバー５の内面には、例えば多孔
質プラスチック、グラスウール、フェルト、ロックウー
ルからなる吸音部材１２を取着している。pl is the outer circumference length of the expansion box portion 9, and fI2 is the inner circumference length. Furthermore, a sound absorbing member 12 made of, for example, porous plastic, glass wool, felt, or rock wool is attached to the inner surface of the fan cover 5.
このような構造において、膨張箱部の外周長さ１１及び
内周長さｆＩ２は、以下の根拠にもとすいて設定されて
いる。In such a structure, the outer circumferential length 11 and inner circumferential length fI2 of the expansion box portion are set based on the following basis.
即ち、冷却ファン４の羽根枚数Ｐしと単位時間当りの回
転数ｍとの積（ｐＸｍ）に相当する周波数ｆＯは、本実
施例では、３６０Ｈｚとなるように設定しており、空気
中の音速Ｃを３４０ｍ／ｓとすると次の（１）式により
波長λを求めることができる。That is, the frequency fO, which corresponds to the product (pXm) of the number of blades P of the cooling fan 4 and the number of rotations per unit time m, is set to 360Hz in this embodiment, and the speed of sound in the air is When C is 340 m/s, the wavelength λ can be determined by the following equation (1).
λ−Ｃ／ｆＯ・・・・・・・・・・・・・・・ （１
）ここでｆＯは周波数（ｍＸｐ）である。λ-C/fO・・・・・・・・・・・・・・・ (1
) where fO is the frequency (mXp).
そして波長λは、ｆＯが３６０Ｈｚの時９４ｃ＋ｎにな
る。そこで膨張箱部９の長さｇｌを減音したい波長λの
１／４の奇数倍になるように設定すれば減衰値の最大に
なる。しかし、膨張箱部９の長さｇｌを一定にしてしま
えば、第３図（ａ）に示すごとく、３６０Ｈ２が減音の
ピークとなり周期的に変化をして７２０Ｈｚでは減音効
果が小さくなってしまう。The wavelength λ is 94c+n when fO is 360Hz. Therefore, if the length gl of the expansion box section 9 is set to be an odd number multiple of 1/4 of the wavelength λ to be attenuated, the attenuation value will be maximized. However, if the length gl of the expansion box section 9 is kept constant, the sound reduction peaks at 360H2 and changes periodically, as shown in Figure 3(a), and the sound reduction effect becomes smaller at 720Hz. Put it away.
そこで、この７２０Ｈｚの減音効果を働かせるために、
膨張箱部９の長さ１１を一定にせずに膨張箱部９の内周
長さｇ２を設定する。Therefore, in order to utilize this 720Hz sound reduction effect,
The inner circumferential length g2 of the expansion box part 9 is set without making the length 11 of the expansion box part 9 constant.
ｆＯが７２０Ｈｚ或いは減音したい周波数ｆが７２０Ｈ
ｚの波長λは４７ｃｙｎになる。そこで、膨張箱９の内
周長さｇ２を波長λの１／４の奇数倍になるように設定
すれば７２０Ｈｚも減衰値の最大になる。つまり、３６
０Ｈｚの１／８波長の奇数倍である。この減衰特性を第
３図（ｂ）に示す。fO is 720Hz or the frequency f you want to reduce is 720H
The wavelength λ of z is 47 cyn. Therefore, if the inner circumferential length g2 of the expansion box 9 is set to be an odd multiple of 1/4 of the wavelength λ, the attenuation value will be maximum at 720 Hz. That is, 36
It is an odd multiple of 1/8 wavelength of 0Hz. This attenuation characteristic is shown in FIG. 3(b).
上記説明したように、波長λと減音したい設定する膨張
箱部９の長さｇの関係は、（２）式により求めることが
できる。As explained above, the relationship between the wavelength λ and the length g of the expansion box section 9 to be set for sound reduction can be determined by equation (2).
ｇ禦（Ｃ／４ｆＯ）（２Ｎ＋１）
−（１／４） ・λ・ （２ｎ＋１）・・・・・・・
・・・・・・・・・・・ （２）但しｎ−０，１，２，
３，・・・
これにより、例えばｎ−０で１１は２３．５ｃｍと算出
でき、ＩＩ２は１１．５ｃｍとすると、最低３６０Ｈｚ
とピークとする減音特性を示すものの周期的変化するも
のと、最高７２０Ｈｚのピークとする減音特性を示すも
のの周期的変化するものが組み重ねあって第３図（ｃ）
の示すごとく減音特性を示し、低周波数域から高周波数
域まで一定に減音効果を示す。g禦(C/4fO)(2N+1) −(1/4) ・λ・ (2n+1)・・・・・・・・・
・・・・・・・・・・・・ (2) However, n-0, 1, 2,
3,... As a result, for example, if n-0, 11 can be calculated as 23.5 cm, and II2 is 11.5 cm, the minimum frequency is 360 Hz.
Figure 3 (c) shows a combination of a periodic variation of the sound reduction characteristic with a peak of 720 Hz and a periodic variation of the sound reduction characteristic with a maximum peak of 720 Hz.
As shown, it exhibits sound reduction characteristics, and exhibits a constant sound reduction effect from the low frequency range to the high frequency range.
また、導風カバー５の内面にこの実施例ではロック・ウ
ール２０ｍｍ厚さのもので接着剤（例えば、商品名スリ
ーボンド）を使用して貼り付けている。Further, in this embodiment, rock wool with a thickness of 20 mm is attached to the inner surface of the air guide cover 5 using an adhesive (for example, Three Bond, trade name).
次に上記構成の作用について説明する。冷却ファン４が
回転すると、外気が吸気ロアａから導風カバー５内に吸
入され、吹出口８ａから回転電機本体１の外周部に向け
て吹出され、これによって回転電機本体１が冷却される
。このとき、冷却ファン４の回転によって騒音が発生し
、その騒音の基本周波数は冷却ファン４の羽根枚数と単
位時間当りの回転数との積に相当する周波数（本実施例
では３６０Ｈｚ）とする。この場合、膨張箱部９の外周
長さ１１を１／４波長に合せであるから、３６０Ｈｚの
音波が膨張箱部９に伝播すると、音波の位相がずれて逆
位相になり、音波が干渉作用により互いに打消し合って
減衰される。これによって基本周波数ｆＯの音と主成分
とする低周波数帯域の騒音が低減される。Next, the operation of the above configuration will be explained. When the cooling fan 4 rotates, outside air is drawn into the air guide cover 5 from the intake lower a, and is blown out from the air outlet 8a toward the outer circumference of the rotating electrical machine main body 1, thereby cooling the rotating electrical machine main body 1. At this time, noise is generated by the rotation of the cooling fan 4, and the fundamental frequency of the noise is a frequency corresponding to the product of the number of blades of the cooling fan 4 and the number of rotations per unit time (360 Hz in this embodiment). In this case, since the outer circumferential length 11 of the expansion box section 9 is set to 1/4 wavelength, when a 360 Hz sound wave propagates to the expansion box section 9, the phase of the sound wave shifts and becomes the opposite phase, and the sound wave causes an interference effect. are attenuated by canceling each other out. This reduces the sound at the fundamental frequency fO and the noise in the low frequency band, which is the main component.
そして、ｇｌの１７４波長は３６０Ｈｚとピークに減音
され７２０Ｈｚの中周波数帯域では減音されない為に、
膨張箱９の内周長さｇ２を３６０Ｈｚの１／８波長に設
定しである。このため、ｇｌで減音されない周波数を補
うことにより、低周波数から中周波数域にいたる全体の
騒音が大幅に低減される。And since the 174 wavelengths of GL are attenuated to a peak of 360Hz, and the mid-frequency band of 720Hz is not attenuated,
The inner circumferential length g2 of the expansion box 9 is set to 1/8 wavelength of 360 Hz. Therefore, by supplementing the frequencies that are not reduced by gl, the overall noise from low frequencies to medium frequency ranges is significantly reduced.
一方、導風カバー５内に設けた吸音材１２によって高周
波数域までも騒音が吸収される。On the other hand, the sound absorbing material 12 provided inside the air guiding cover 5 absorbs noise even in a high frequency range.
本発明者は、従来の吸音部材のみを使用した場合と本実
施例とについてそれぞれ減音効果を測定した。その結果
を第４図（ａ）と（ｂ）に示す。The present inventor measured the sound reduction effect of the case where only the conventional sound absorbing member was used and the case of this example. The results are shown in FIGS. 4(a) and 4(b).
図中、斜線で示す部分が減音効果を示しており、従来の
第４図（ａ）では、低周波数騒音が全く低減されていな
い。これに対して、本実施例の第４図（ｂ）では、低周
波数帯域の騒音が効果的に低減されて全体として十分に
低騒音化されていることが分る。In the figure, the shaded area shows the sound reduction effect, and in the conventional example shown in FIG. 4(a), low frequency noise is not reduced at all. On the other hand, in FIG. 4(b) of this embodiment, it can be seen that the noise in the low frequency band is effectively reduced and the noise is sufficiently reduced as a whole.
また、減音効果を示すのにもう一つの要因でもある膨張
箱部９と入口管１１および尾管１０の径の比は、できる
だけ大きくすることにより減音効果を増大させることは
言うまでもない。It goes without saying that the ratio of the diameters of the expansion box section 9, the inlet pipe 11, and the tail pipe 10, which is another factor in exhibiting the sound reduction effect, is increased as much as possible to increase the sound reduction effect.
第２図は、本発明の第２実施例を示したもので、この第
２実施例では、第１実施例に比較して膨張箱部９の外周
長さＲ１と内周長さｇ２を設定してｇｌとＪ？２をスト
レートに結んだが、ｐｌとｐ２の間に階段状に１２３．
１４を設けである。これは、ｆｌｌと１２さえ設定すれ
ば良いのであるから１１≦ｆＩｉ≦ｇ２の関係であれば
ストレートであろうとと階段状であろうと同様の効果が
得られる。FIG. 2 shows a second embodiment of the present invention. In this second embodiment, the outer circumference length R1 and inner circumference length g2 of the expansion box portion 9 are set as compared to the first embodiment. And gl and J? 2 was tied straight, but 123. was tied in a stepped manner between pl and p2.
14 is provided. This is because it is only necessary to set fll and 12, so if the relationship is 11≦fIi≦g2, the same effect can be obtained regardless of whether it is straight or stepped.
尚、上記各実施例では、膨張箱部９の外周長さｇｌおよ
び内周長さｆＩ２を３６０Ｈｚに対して設定したが、こ
れに限らず騒音に応じて適宜選択すれば良い。要旨を逸
脱しない範囲で種々変形可能である。In each of the above embodiments, the outer circumferential length gl and inner circumferential length fI2 of the expansion box portion 9 are set to 360 Hz, but they are not limited to this and may be appropriately selected depending on the noise level. Various modifications can be made without departing from the gist.
［発明の効果］
本発明は以上の説明から明らかなように、膨張箱部の外
周長さと内周長さを設定し、例えば低周波数帯域におけ
る主要な騒音の周波数の波長に一致させることにより干
渉作用を生じさせ、その騒音を効率良く減衰させること
ができる。従って、全体として十分な低騒音化を図り得
るという優れた効果を奏する。[Effects of the Invention] As is clear from the above description, the present invention eliminates interference by setting the outer circumferential length and inner circumferential length of the expansion box portion to match the wavelength of the main noise frequency in the low frequency band, for example. effect, and the noise can be efficiently attenuated. Therefore, the excellent effect of achieving sufficient noise reduction as a whole is achieved.
第１図は本発明の第１実施例として示す回転電機の要部
断面図、第２図は本発明の第２実施例として示す要部断
面図、第３図は減音効果の説明図中、１は回転電機本体
、２は冷却フィン、３は回転軸、４は冷却ファン、５は
導風カバー、６は保護網、７は吸気室、８は送風室、９
は膨張箱部、１０は尾管、１１は入口管、１２は吸音部
材である。
５斗瓜ツバ−
第１悶
・１）２ ρ］
第Ｊ凶
第４２
ノ
第５スFig. 1 is a cross-sectional view of the main parts of a rotating electrical machine shown as a first embodiment of the present invention, Fig. 2 is a cross-sectional view of main parts shown as a second embodiment of the invention, and Fig. 3 is an explanatory diagram of the sound reduction effect. , 1 is the rotating electric machine main body, 2 is the cooling fin, 3 is the rotating shaft, 4 is the cooling fan, 5 is the wind guide cover, 6 is the protective net, 7 is the intake chamber, 8 is the ventilation chamber, 9
1 is an expansion box part, 10 is a tail pipe, 11 is an inlet pipe, and 12 is a sound absorbing member. 5 Doukatsuba - 1st agony 1) 2 ρ] J Kyou No. 42 No. 5
Claims (1)
風を前記回転電機本体の外周部に導くための導風カバー
を前記回転電機本体に取着したものにおいて、前記導風
カバーに、その内部を伝播する所定の周波数を外す波長
の１／４波長の奇数倍の長さを有するものと、前記所定
の周波数の波長の１／８波長の奇数倍の長さを有するも
のとを組合せた膨張箱部を設けたことを特徴とする回転
電機の消音装置。A wind guide cover is attached to the rotary electric machine main body for guiding wind generated by a cooling fan provided outside the rotary electric machine main body to an outer peripheral part of the rotary electric machine main body, and the inside of the rotary electric machine body is attached to the rotary electric machine main body. An expansion box that combines an expansion box with a length that is an odd multiple of 1/4 wavelength of the wavelength that excludes a predetermined frequency to be propagated, and an expansion box that has a length that is an odd multiple of 1/8 wavelength of the wavelength of the predetermined frequency. A noise muffling device for a rotating electrical machine, characterized by having a section.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13181987A JPH01138949A (en) | 1987-05-29 | 1987-05-29 | Sound attenuating device for rotary electric machine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13181987A JPH01138949A (en) | 1987-05-29 | 1987-05-29 | Sound attenuating device for rotary electric machine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH01138949A true JPH01138949A (en) | 1989-05-31 |
Family
ID=15066841
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13181987A Pending JPH01138949A (en) | 1987-05-29 | 1987-05-29 | Sound attenuating device for rotary electric machine |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH01138949A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10220302B2 (en) | 2002-07-27 | 2019-03-05 | Sony Interactive Entertainment Inc. | Method and apparatus for tracking three-dimensional movements of an object using a depth sensing camera |
| USRE48417E1 (en) | 2006-09-28 | 2021-02-02 | Sony Interactive Entertainment Inc. | Object direction using video input combined with tilt angle information |
-
1987
- 1987-05-29 JP JP13181987A patent/JPH01138949A/en active Pending
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US10220302B2 (en) | 2002-07-27 | 2019-03-05 | Sony Interactive Entertainment Inc. | Method and apparatus for tracking three-dimensional movements of an object using a depth sensing camera |
| USRE48417E1 (en) | 2006-09-28 | 2021-02-02 | Sony Interactive Entertainment Inc. | Object direction using video input combined with tilt angle information |
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