JP4364323B2 - Rotational speed adjustment device for pneumatic tool - Google Patents

Rotational speed adjustment device for pneumatic tool Download PDF

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JP4364323B2
JP4364323B2 JP21416298A JP21416298A JP4364323B2 JP 4364323 B2 JP4364323 B2 JP 4364323B2 JP 21416298 A JP21416298 A JP 21416298A JP 21416298 A JP21416298 A JP 21416298A JP 4364323 B2 JP4364323 B2 JP 4364323B2
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speed adjusting
air
speed
adjusting member
rotary tool
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JPH11320455A (en
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正 神谷
利郎 入谷
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株式会社ケーティーエス
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Description

【０００１】
【発明の属する技術分野】
本発明は、空気回転工具において最大回転数をある程度以上にならないように制御するようにした空気回転工具の回転速度調節装置に関する。
【０００２】
【従来の技術】
エアグラインダーやエアサンダー等の空気回転工具は、砥石等の回転研削物あるいは回転研磨物等の加工工具を回転させて被研磨物等を研磨するものである。加工工具は低速よりも高速の方が研削性や研磨性が良く、しかも作業性も優れている。
空気回転工具では一般に、使用する圧力（常用圧力）が取扱説明書等で指示されている。しかし、使用する圧力の指示が無視されて、はるかに高い圧力で使用されているのが実情である。図７に示すように、空気圧力を上げてゆけば、加工工具の回転数は、一点鎖線（ａ）のように許容回転数を越えるようになる。
【０００３】
【発明が解決しようとする課題】
空気回転工具が許容回転数を越えると、加工工具に強度以上の回転力（遠心力）が働いて加工工具が破壊するおそれがある。加工工具が破壊すると、破壊物が四方に飛散して作業者や周囲の人にが怪我をするおそれがあり、極めて危険である。この点から、エアグラインダーやエアサンダー等の空気回転工具では、回転数を最大許容回転数以下に押える必要があった。即ち、図７の実線（ｂ）のように許容回転数を越えないものが望ましい。
また、空気回転工具が許容回転数を越えないように維持するために、自動的に空気供給量を調節して、モータ回転数が所定の回転数の範囲内で増加と減少とを繰り返そうとする。このモータ回転数の増加或は減少との繰り返し動作において回転速度調節装置の速度調節部材が軸方向に伸縮振動を起こすという欠点があった。
【０００４】
本発明は上記の点に鑑みてなされたもので、高い空気圧力が供給されても最大許容回転数を越えないようにして加工工具の破損を生じないようにした空気回転工具の回転速度調節装置を提供することを目的とするものである。
本発明はまた、振動による回転ムラの生じることのない空気回転工具の回転速度調節装置を提供することを目的とするものである。
【０００５】
【課題を解決するための手段】
上記の目的を達成するために本発明の空気回転工具の回転速度調節装置は、内部に空気導入通路を形成したメインボディと、その空気導入通路から供給される空気によって回転力を発生させるための回転力発生手段と、その回転力発生手段の構成部材としてのロータとを有する空気回転工具において、前記メインボディに通路断面の狭いベンチュリー部を形成し、前記ロータの一端に速度調節用シャフトを固定し、この速度調節用シャフトに対して変位可能であって形状を一端閉鎖の筒状とした速度調節用部材を備え、前記速度調節用シャフトの回転中心軸に対する半径方向に移動可能で速度調節用部材にボールを備え、そのボールにかかる遠心力で速度調節用部材を前記速度調節用シャフトの回転中心軸の軸方向に対して変位させ、前記ロータの回転数が許容回転数近辺に達した場合の速度調節用部材の変位位置で前記速度調節用部材の先端と前記ベンチュリー部との間の空気導入通路の断面を狭くして前記ロータの回転数が許容回転数を越えない供給空気量とするようにし、前記速度調節用部材の変位によって前記速度調節用部材と速度調節用シャフトの先端との間に空間を形成するようにし、前記速度調節用部材の先端閉鎖側に形成される突出部に前記空間と前記空気導入通路とを連絡する貫通小孔を形成し減衰効果を持たせるようにしたものである。
【０００６】
【発明の実施の形態】
次に本発明を図面に基づいて説明する。
図１は本発明に係る回転速度調節装置を備えた空気回転工具の全体断面図、図２は図１の要部拡大縦断面図である。図３は図２の要部拡大縦断面図である。
空気回転工具は、メインボディ１０と、その内部に加圧空気を導入するために形成された空気導入通路１２と、その空気導入通路１２からの供給空気によって回転力を発生させるための回転力発生手段１４とを有している。この空気回転工具に、砥石等の回転研削物や回転研磨物等の加工工具１６が着脱自在に取り付けられる。
回転力発生手段１４は、ハウジングとなるシリンダ１８とフロントプレート２０とリアプレート２２を有し、そのハウジングの内部に空間２４を形成し、その空間２４の内部にロータ２６とそのロータ２６に半径方向に出入りする複数のベーン２８とを備えたものである。回転力発生手段１４の空間２４内に空気導入通路１２からの空気が供給され、その供給空気がベーン２８に当たってロータ２６を回転させ、それによって加工工具１６を回転させる。
【０００７】
図２に示すように、ロータ２６のリアプレート２２側の自由端に、速度調節用シャフト３０が回転中心軸を同一にして固定される。この速度調節用シャフト３０は前記空気導入通路１２内に位置している。速度調節用シャフト３０の外側には、キャップ状の速度調節用部材３２が被せられており、速度調節用部材３２の筒状の内壁は速度調節用シャフト３０の外壁に摺接しながら移動するように設定されている。この速度調節用部材３２の筒状の側面には、軸方向に一対の穴３４が形成される。
速度調節用シャフト３０には、軸方向と直角方向に速度調節用シャフト３０と速度調節用部材３２の穴３４を貫通するピン３６が固定され、そのピン３６の両端は速度調節用部材３２の穴３４の外側に突出している。
速度調節用部材３２の穴３４の外側に突出しているピン３６の両端には、カバー３８が被せられて、そのカバー３８と速度調節用部材３２のリアプレート２２側との間にスプリング４０が備えられる。このスプリング４０は、速度調節用部材３２を常にロータ２６側に向けて付勢するためのものである。
【０００８】
前記速度調節用シャフト３０には、軸中心に対して直角な面に、外表面から軸中心に向けてやや内側に伸びる複数個の孔４２が形成され、各孔４２にはボール４４が備えられる。
前記キャップ状の速度調節用部材３２の筒状の端付近の内壁は、軸方向から外側に向けて徐々に開く形状の傾斜壁４６となっている。前記ボール４４はこの傾斜壁４６に接触している。
メインボディ１０の内部に形成される空気導入通路１２の途中には、図３に示すようにベンチュリー部４８が形成され、そのベンチュリー部４８の直径をＤとする。
【０００９】
キャップ状の速度調節用部材３２は、図３に示すように、速度調節用シャフト３０の外側の筒状部５０と、先端閉鎖部５２と、その先端閉鎖部５２に形成されるもので前記筒状部５０より直径が小さい突出部５４とからなる。更に、この突出部５４の先端付近には、先端に近づくにつれて先細となるテーパ部５６を形成する。この突出部５４の径大部の直径をｄとすると、この直径ｄはベンチュリー部４８の直径Ｄより小さいものに設定する。
なお、キャップ状の速度調節用部材３２においては、図３に示すように、テーパ状の突出部５４の根元の外径を前記筒状部５０の外径をより小さいものとしたが、テーパ状の突出部５４の根元の外径を筒状部５０の外径と同一にするようにしても良い。また、テーパ状をストレート状にしても良い。
突出部５４には、そこを貫通して前記筒状部５０の内部に通じる貫通小孔５８が形成されている。先端閉鎖部５２に突出部５４が形成されていない場合には、先端閉鎖部５２に内部に通じる貫通小孔５８を形成するようにしても良い。
【００１０】
次に、動作について説明する。
空気導入通路１２からの加圧空気の供給空気量が多くなると、回転力発生手段１４のロータ２６の回転数が上昇し、ロータ２６に固定されている速度調節用シャフト３０の回転数も上昇する。速度調節用シャフト３０の回転数が増大すると、その孔４２に収容されているボール４４に遠心力が与えられる。
速度調節用シャフト３０の回転数の増加に応じてボール４４が傾斜壁４６を押す力が大きくなり、図２並びに図３で速度調節用部材３２を右方向に移動させる。即ち、速度調節用シャフト３０の回転数の増加に応じて、速度調節用部材３２を図２並びに図３で右方向に移動する。速度調節用シャフト３０の回転数が所定以上になると、速度調節用部材３２の突出部５４がベンチュリー部４８に突入し、図３及び図４に示すようにベンチュリー部４８における空気導入通路１２の通路断面が狭くなり、空気導入通路１２から回転力発生手段１４への供給空気量が制限される。この結果、図５に示すように、速度調節用シャフト３０の回転数は最大許容回転数を大きく越えることがない。
【００１１】
突出部５４の先端付近に先細となるテーパ部５６を付けることによって、空気の流れがスムースになり、応答性や安定性が良い。なお、図１乃至図３においては、突出部５４の先端付近のみにテーパ部５６を設けたが、図６に示すように、突出部５４の軸方向の全長にわたって先細となるテーパ部６０を形成しても良い。なお、突出部５４を円柱形状にしても良い。
図４に示すように、ベンチュリー部４８におけるメインボディ１０と突出部５４との隙間Ｓは、突出部５４を一段細くしたことにより大きくすることができるので、空気回転工具の振動等により突出部５４が若干振れても、ベンチュリー部４８におけるメインボディ１０と突出部５４とが接触することはなく、速度調節用部材３２の摺動性に影響は無い。
【００１２】
図３に示すように、速度調節用シャフト３０に対して速度調節用部材３２が離れる方向に変位すると、速度調節用部材３２の先端閉鎖部５２と速度調節用シャフト３０の先端面との間に空間６２が形成される。速度調節用シャフト３０の先端閉鎖部５２の突出部５４に形成される貫通小孔５８は、一方を空間６２と連絡し、他方を前記空気導入通路１２と連絡する。
もし、速度調節用部材３２に空間６２に至る貫通小孔５８が形成されないとすると、空間６２の容積が大きくなるとその空間６２内に大きな負圧が発生し、速度調節用部材３２の応答性や安定性が悪くなる。このため、速度調節用部材３２に空間６２と空気導入通路１２とを連絡する貫通小孔５８を形成することによって、貫通小孔５８からこの空間６２に空気が出入りして、速度調節用部材３２の移動をスムースに行わせることができる。
【００１３】
従来から、工具の回転速度調節装置においては、モータ回転数の増加或は減少という繰り返し動作が行われ、ロータに回転ムラが生じるという欠点があった。本発明においては、遠心力を発生するボール４４の重量や、スプリング４０の強さや、速度調節用シャフト３０と速度調節用部材３２の摺動部分の摺動抵抗や、供給空気の流量や圧力の具合によって、速度調節用部材３２が速度調節用シャフト３０に対して軸方向に振動し、その振動によって流入空気量が変化し、その流入空気量の変化によってロータ２６に回転ムラが発生するおそれがあった。
【００１４】
しかし、空間６２と空気導入通路１２とを連絡する貫通小孔５８を速度調節用部材３２に形成することによって、この貫通小孔５８を出入りする空気の抵抗が速度調節用シャフト３０に対する速度調節用部材３２の軸方向の振動を解消する。即ち、回転力発生手段１４の回転が上昇すると、空気導入通路１２から貫通小孔５８を経て空間６２に移動する空気の流入抵抗が発生し、この空気の流入抵抗が速度調節用部材３２に発生する軸方向の振動を防止し、ロータ２６の回転ムラを防止する。また、回転力発生手段１４の回転が下降すると、空間６２から貫通小孔５８を経て空気導入通路１２に移動する空気の流出抵抗が発生し、この空気の流出抵抗が速度調節用部材３２に発生する軸方向の振動を防止し、ロータ２６の回転ムラを防止する。
【００１５】
前記貫通小孔５８の直径を０．５ｍｍ〜２ｍｍ（上下の数値を含むものとする）にすれば、速度調節用シャフト３０に対する速度調節用部材３２の軸方向の振動をなくし、ロータ２６の回転ムラを解消することができる。貫通小孔５８の直径を０．５ｍｍ〜２ｍｍ程度の小さいものとすることによって、貫通小孔５８を通過する空気の抵抗力を十分利用することができ、この空気抵抗力によって回転速度調節装置の速度調節用部材３２に発生する振動をなくし、ロータ２６の回転ムラを防止することができる。貫通小孔５８の直径が０．５ｍｍより小さくなると、空気の抵抗力は大となるが、貫通小孔５８の加工の難易さやゴミ等の目詰まり等を考慮すると好ましくない。貫通小孔５８の直径が２ｍｍより大きくなると、貫通小孔５８を通過する空気の抵抗力が弱くなり、速度調節用部材３２の軸方向の振動を抑制する効果が殆どなくなる。
実際に使用される回転速度調節装置では、空間６２の内径は５０ｍｍ以下であるので、この間におけるどのような内径の空間６２に対しても、貫通小孔５８の直径は０．５ｍｍ〜２ｍｍ（上下の数値を含むものとする）の範囲で十分である。
【００１６】
【発明の効果】
以上のように、本発明に係わる空気回転工具の回転速度調節装置によれば、ロータの回転数が所定以上に達すると、ロータに固定される速度調節用シャフトに対して軸方向に移動する速度調節用部材によって、空気導入通路から回転力発生手段への供給空気量を制限する。このように、ロータの回転数が所定の値に達すると空気導入通路からの供給空気量を制限するので、ロータの回転数を最大許容回転数を越えなくすることができ、この結果、回転研削物や回転研磨物等の加工工具の破損を防止することができる。
また、速度調節用シャフトと速度調節用部材との間に形成される空間と空気導入通路との間に、それら空間と空気導入通路とを連絡する貫通小孔を形成することによって、その貫通小孔を通過する空気の抵抗力によって、速度調節用部材に発生する軸方向の振動を防いで、ロータの回転ムラを防止して安定的な回転を行うことができる。
更に、速度調節用部材の先端突出部にテーパ部を設けることによって、空気の流れがスムースになり、応答性や安定性を良くすることができる。
【図面の簡単な説明】
【図１】本発明に係る回転速度調節装置を備えた空気回転工具の全体断面図である。
【図２】図１の要部拡大縦断面図である。
【図３】図２の要部拡大縦断面図である。
【図４】ベンチュリー部におけるメインボディと速度調節用部材の要部断面図である。
【図５】本発明に係る回転速度調節装置を備えた空気回転工具の回転数と時間の特性図である。
【図６】速度調節用部材の他の形状を示す部分断面図である。
【図７】従来の空気回転工具の回転数と圧力の特性図である。
【符合の説明】
１０ メインボディ
１２ 空気導入通路
１４ 回転力発生手段
１６ 加工工具
２６ ロータ
３０ 速度調節用シャフト
３２ 速度調節用部材
３４ 穴
４０ スプリング
４４ ボール
４６ 傾斜壁
４８ ベンチュリー部
５０ 筒状部
５２ 先端閉鎖部
５４ 突出部
５６ テーパ部
５８ 貫通小孔
６０ テーパ部
６２ 空間[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rotational speed adjusting device for an air rotary tool that is controlled so that the maximum rotational speed of the pneumatic rotary tool does not exceed a certain level.
[0002]
[Prior art]
An air rotary tool such as an air grinder or an air sander is for polishing a workpiece or the like by rotating a rotary grinding product such as a grindstone or a processing tool such as a rotary polishing product. Processing tools have better grindability and polishability at higher speeds than low speeds, and workability is also excellent.
In general, the pressure (usually used pressure) to be used in an air rotary tool is indicated in an instruction manual or the like. However, the fact that the pressure indication to be used is ignored and the pressure is used at a much higher pressure. As shown in FIG. 7, when the air pressure is increased, the rotational speed of the machining tool exceeds the allowable rotational speed as indicated by the alternate long and short dash line (a).
[0003]
[Problems to be solved by the invention]
If the pneumatic rotary tool exceeds the permissible rotational speed, a rotational force (centrifugal force) higher than the strength may act on the machining tool and the machining tool may be destroyed. If the processing tool is broken, the broken object may scatter in all directions, which may cause injury to the worker and the surrounding people, which is extremely dangerous. From this point, it is necessary to keep the rotation speed below the maximum allowable rotation speed in an air rotary tool such as an air grinder or an air sander. That is, it is desirable that the allowable rotational speed is not exceeded as shown by the solid line (b) in FIG.
Further, in order to maintain the pneumatic tool so as not to exceed the allowable rotational speed, the air supply amount is automatically adjusted so that the motor rotational speed repeatedly increases and decreases within a predetermined rotational speed range. . There has been a drawback that the speed adjusting member of the rotation speed adjusting device causes expansion and contraction vibration in the axial direction in the repeated operation of increasing or decreasing the motor rotation speed.
[0004]
SUMMARY OF THE INVENTION The present invention has been made in view of the above points. An apparatus for adjusting the rotational speed of an air rotary tool that does not exceed the maximum allowable rotational speed even when a high air pressure is supplied so as not to damage the machining tool. Is intended to provide.
Another object of the present invention is to provide an apparatus for adjusting the rotational speed of an air rotary tool that does not cause uneven rotation due to vibration.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, a rotational speed adjusting device for an air rotary tool according to the present invention includes a main body having an air introduction passage formed therein, and a rotational force generated by air supplied from the air introduction passage . In a pneumatic rotary tool having a rotational force generating means and a rotor as a component of the rotational force generating means, a venturi portion having a narrow passage section is formed in the main body, and a speed adjusting shaft is fixed to one end of the rotor And a speed adjusting member which is displaceable with respect to the speed adjusting shaft and has a cylindrical shape whose end is closed at one end, and is movable in a radial direction with respect to the rotation center axis of the speed adjusting shaft. The member is provided with a ball, and the speed adjusting member is displaced with respect to the axial direction of the rotation center axis of the speed adjusting shaft by centrifugal force applied to the ball, and the rod The rotation of the rotor by narrowing the cross section of the air introduction passage between the tip of the speed adjusting member and the venturi at the displacement position of the speed adjusting member when the rotation speed of the rotor reaches around the allowable rotation speed. The supply air amount is such that the number does not exceed an allowable rotation speed, and a space is formed between the speed adjustment member and the tip of the speed adjustment shaft by displacement of the speed adjustment member, and the speed adjustment A through hole that connects the space and the air introduction passage is formed in a protrusion formed on the front end closing side of the member for use so as to have a damping effect.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described with reference to the drawings.
FIG. 1 is an overall cross-sectional view of an air rotary tool provided with a rotation speed adjusting device according to the present invention, and FIG. 2 is an enlarged vertical cross-sectional view of a main part of FIG. FIG. 3 is an enlarged vertical sectional view of the main part of FIG.
The air rotating tool includes a main body 10, an air introduction passage 12 formed to introduce pressurized air into the main body 10, and generation of a rotational force for generating a rotational force by air supplied from the air introduction passage 12. Means 14. A processing tool 16 such as a rotating grinding object such as a grindstone or a rotating polishing object is detachably attached to the pneumatic rotating tool.
The rotational force generating means 14 includes a cylinder 18 serving as a housing, a front plate 20, and a rear plate 22. A space 24 is formed inside the housing, and a rotor 26 and a rotor 26 are radially formed inside the space 24. And a plurality of vanes 28 entering and exiting. Air from the air introduction passage 12 is supplied into the space 24 of the rotational force generating means 14, and the supplied air hits the vane 28 to rotate the rotor 26, thereby rotating the processing tool 16.
[0007]
As shown in FIG. 2, the speed adjusting shaft 30 is fixed to the free end of the rotor 26 on the rear plate 22 side with the same rotation center axis. The speed adjusting shaft 30 is located in the air introduction passage 12. A cap-shaped speed adjusting member 32 is placed on the outer side of the speed adjusting shaft 30 so that the cylindrical inner wall of the speed adjusting member 32 moves while sliding on the outer wall of the speed adjusting shaft 30. Is set. A pair of holes 34 are formed on the cylindrical side surface of the speed adjusting member 32 in the axial direction.
Pins 36 that pass through the holes 34 of the speed adjusting shaft 30 and the speed adjusting member 32 in a direction perpendicular to the axial direction are fixed to the speed adjusting shaft 30, and both ends of the pin 36 are holes of the speed adjusting member 32. 34 protrudes outside.
Covers 38 are put on both ends of the pin 36 protruding outside the hole 34 of the speed adjusting member 32, and a spring 40 is provided between the cover 38 and the rear plate 22 side of the speed adjusting member 32. It is done. The spring 40 is used to constantly urge the speed adjusting member 32 toward the rotor 26 side.
[0008]
The speed adjusting shaft 30 is formed with a plurality of holes 42 extending inward from the outer surface toward the axis center on a plane perpendicular to the axis center, and each hole 42 is provided with a ball 44. .
The inner wall in the vicinity of the cylindrical end of the cap-shaped speed adjusting member 32 is an inclined wall 46 that gradually opens outward from the axial direction. The ball 44 is in contact with the inclined wall 46.
A venturi portion 48 is formed in the middle of the air introduction passage 12 formed in the main body 10 as shown in FIG. 3, and the diameter of the venturi portion 48 is D.
[0009]
As shown in FIG. 3, the cap-shaped speed adjusting member 32 is formed in the cylindrical portion 50 on the outer side of the speed adjusting shaft 30, the tip closing portion 52, and the tip closing portion 52. The protrusion portion 54 has a diameter smaller than that of the shape portion 50. Further, a tapered portion 56 that tapers toward the tip is formed near the tip of the protrusion 54. When the diameter of the large diameter portion of the projecting portion 54 is d, the diameter d is set to be smaller than the diameter D of the venturi portion 48.
In the cap-shaped speed adjusting member 32, the outer diameter of the base of the tapered protrusion 54 is smaller than the outer diameter of the cylindrical portion 50 as shown in FIG. The outer diameter of the base of the protruding portion 54 may be the same as the outer diameter of the cylindrical portion 50. Further, the taper shape may be a straight shape.
The projecting portion 54 is formed with a through small hole 58 that passes through the projecting portion 54 and communicates with the inside of the cylindrical portion 50. When the protruding portion 54 is not formed on the tip closing portion 52, a through hole 58 that communicates with the tip closing portion 52 may be formed.
[0010]
Next, the operation will be described.
When the amount of pressurized air supplied from the air introduction passage 12 increases, the rotational speed of the rotor 26 of the rotational force generating means 14 increases, and the rotational speed of the speed adjusting shaft 30 fixed to the rotor 26 also increases. . When the rotational speed of the speed adjusting shaft 30 increases, a centrifugal force is applied to the ball 44 accommodated in the hole 42.
As the rotational speed of the speed adjusting shaft 30 increases, the force with which the ball 44 pushes the inclined wall 46 increases, and the speed adjusting member 32 is moved to the right in FIGS. That is, the speed adjusting member 32 is moved in the right direction in FIGS. 2 and 3 in accordance with an increase in the rotational speed of the speed adjusting shaft 30. When the rotational speed of the speed adjusting shaft 30 exceeds a predetermined value, the protruding portion 54 of the speed adjusting member 32 enters the venturi 48, and the passage of the air introduction passage 12 in the venturi 48 as shown in FIGS. The cross section becomes narrow, and the amount of air supplied from the air introduction passage 12 to the rotational force generating means 14 is limited. As a result, as shown in FIG. 5, the rotational speed of the speed adjusting shaft 30 does not greatly exceed the maximum allowable rotational speed.
[0011]
By attaching the taper part 56 which tapers near the front-end | tip of the protrusion part 54, the flow of air becomes smooth and responsiveness and stability are good. 1 to 3, the tapered portion 56 is provided only in the vicinity of the tip of the protruding portion 54. However, as shown in FIG. 6, a tapered portion 60 that is tapered over the entire axial length of the protruding portion 54 is formed. You may do it. Note that the protruding portion 54 may be cylindrical.
As shown in FIG. 4, the clearance S between the main body 10 and the protruding portion 54 in the venturi portion 48 can be increased by making the protruding portion 54 thinner by one step, so that the protruding portion 54 is caused by vibration of the pneumatic tool or the like. The main body 10 and the projecting portion 54 in the venturi portion 48 do not come into contact with each other even if they slightly swing, and the slidability of the speed adjusting member 32 is not affected.
[0012]
As shown in FIG. 3, when the speed adjusting member 32 is displaced in a direction away from the speed adjusting shaft 30, it is between the tip closing portion 52 of the speed adjusting member 32 and the tip surface of the speed adjusting shaft 30. A space 62 is formed. One through hole 58 formed in the protrusion 54 of the tip closing portion 52 of the speed adjusting shaft 30 communicates with the space 62 and the other communicates with the air introduction passage 12.
If the through hole 58 reaching the space 62 is not formed in the speed adjusting member 32, a large negative pressure is generated in the space 62 when the volume of the space 62 is increased. Stability deteriorates. For this reason, by forming the through small hole 58 that connects the space 62 and the air introduction passage 12 in the speed adjusting member 32, air enters and leaves the space 62 from the through small hole 58, and the speed adjusting member 32. Can be moved smoothly.
[0013]
Conventionally, in a tool rotation speed adjusting device, there has been a drawback in that a rotation operation is repeatedly performed to increase or decrease the motor rotation speed, resulting in uneven rotation of the rotor. In the present invention, the weight of the ball 44 that generates centrifugal force, the strength of the spring 40, the sliding resistance of the sliding portion of the speed adjusting shaft 30 and the speed adjusting member 32, the flow rate and pressure of the supply air Depending on the condition, the speed adjusting member 32 may vibrate in the axial direction with respect to the speed adjusting shaft 30, and the vibration may change the amount of inflow air, and the change in the amount of inflow air may cause rotation unevenness in the rotor 26. there were.
[0014]
However, by forming the through hole 58 that connects the space 62 and the air introduction passage 12 in the speed adjusting member 32, the resistance of the air entering and exiting the through hole 58 is used for speed adjustment with respect to the speed adjusting shaft 30. The vibration in the axial direction of the member 32 is eliminated. That is, when the rotation of the rotational force generating means 14 rises, an inflow resistance of air moving from the air introduction passage 12 through the through small hole 58 to the space 62 is generated, and this inflow resistance of air is generated in the speed adjusting member 32. Thus, the vibration in the axial direction is prevented, and the rotation unevenness of the rotor 26 is prevented. Further, when the rotation of the rotational force generating means 14 is lowered, an outflow resistance of air moving from the space 62 to the air introduction passage 12 through the through small hole 58 is generated, and this outflow resistance of the air is generated in the speed adjusting member 32. Thus, the vibration in the axial direction is prevented, and the rotation unevenness of the rotor 26 is prevented.
[0015]
When the diameter of the through hole 58 is 0.5 mm to 2 mm (including upper and lower numerical values), vibration in the axial direction of the speed adjusting member 32 relative to the speed adjusting shaft 30 is eliminated, and rotation unevenness of the rotor 26 is prevented. Can be resolved. By making the diameter of the small through hole 58 as small as about 0.5 mm to 2 mm, the resistance force of the air passing through the through small hole 58 can be sufficiently utilized. The vibration generated in the speed adjusting member 32 can be eliminated, and uneven rotation of the rotor 26 can be prevented. When the diameter of the through small hole 58 is smaller than 0.5 mm, the air resistance increases, but it is not preferable in consideration of difficulty in processing the through small hole 58 and clogging of dust. If the diameter of the through small hole 58 is larger than 2 mm, the resistance force of the air passing through the through small hole 58 becomes weak, and the effect of suppressing the vibration in the axial direction of the speed adjusting member 32 is almost lost.
In the rotational speed adjusting device that is actually used, the inner diameter of the space 62 is 50 mm or less. Therefore, the diameter of the through small hole 58 is 0.5 mm to 2 mm (up and down) with respect to the space 62 having any inner diameter in the meantime. Is included).
[0016]
【The invention's effect】
As described above, according to the rotational speed adjusting device for a pneumatic tool according to the present invention, when the rotational speed of the rotor reaches a predetermined value or more, the speed of moving in the axial direction with respect to the speed adjusting shaft fixed to the rotor. The amount of air supplied from the air introduction passage to the rotational force generating means is limited by the adjusting member. As described above, when the rotational speed of the rotor reaches a predetermined value, the amount of air supplied from the air introduction passage is limited. Therefore, the rotational speed of the rotor can be prevented from exceeding the maximum allowable rotational speed. It is possible to prevent breakage of a processing tool such as a workpiece or a rotating abrasive.
Further, by forming a through small hole connecting the space and the air introduction passage between the space formed between the speed adjustment shaft and the speed adjustment member and the air introduction passage, the through small hole is formed. The resistance force of the air passing through the hole prevents the axial vibration generated in the speed adjusting member, thereby preventing uneven rotation of the rotor and performing stable rotation.
Furthermore, by providing the tapered portion at the tip protruding portion of the speed adjusting member, the air flow becomes smooth, and the responsiveness and stability can be improved.
[Brief description of the drawings]
FIG. 1 is an overall cross-sectional view of a pneumatic rotary tool equipped with a rotational speed adjusting device according to the present invention.
FIG. 2 is an enlarged vertical sectional view of a main part of FIG.
3 is an enlarged vertical cross-sectional view of a main part of FIG. 2;
FIG. 4 is a cross-sectional view of a main part of a main body and a speed adjusting member in a venturi part.
FIG. 5 is a characteristic diagram of rotational speed and time of an air rotary tool provided with a rotational speed adjusting device according to the present invention.
FIG. 6 is a partial cross-sectional view showing another shape of the speed adjusting member.
FIG. 7 is a characteristic diagram of rotation speed and pressure of a conventional pneumatic rotary tool.
[Explanation of sign]
DESCRIPTION OF SYMBOLS 10 Main body 12 Air introduction channel | path 14 Rotational force generating means 16 Processing tool 26 Rotor 30 Speed adjustment shaft 32 Speed adjustment member 34 Hole 40 Spring 44 Ball 46 Inclined wall 48 Venturi part 50 Cylindrical part 52 Tip closing part 54 Projection part 56 Tapered portion 58 Small through-hole 60 Tapered portion 62 Space

Claims (5)

内部に空気導入通路を形成したメインボディと、その空気導入通路から供給される空気によって回転力を発生させるための回転力発生手段と、その回転力発生手段の構成部材としてのロータとを有する空気回転工具において、前記メインボディに通路断面の狭いベンチュリー部を形成し、前記ロータの一端に速度調節用シャフトを固定し、この速度調節用シャフトに対して変位可能であって形状を一端閉鎖の筒状とした速度調節用部材を備え、前記速度調節用シャフトの回転中心軸に対する半径方向に移動可能で速度調節用部材にボールを備え、そのボールにかかる遠心力で速度調節用部材を前記速度調節用シャフトの回転中心軸の軸方向に対して変位させ、前記ロータの回転数が許容回転数近辺に達した場合の速度調節用部材の変位位置で前記速度調節用部材の先端と前記ベンチュリー部との間の空気導入通路の断面を狭くして前記ロータの回転数が許容回転数を越えない供給空気量とするようにし、前記速度調節用部材の変位によって前記速度調節用部材と速度調節用シャフトの先端との間に空間を形成するようにし、前記速度調節用部材の先端閉鎖側に形成される突出部に前記空間と前記空気導入通路とを連絡する貫通小孔を形成したことを特徴とする空気回転工具の回転速度調節装置。Air having a main body in which an air introduction passage is formed, a rotational force generating means for generating a rotational force by the air supplied from the air introduction passage, and a rotor as a component of the rotational force generation means In the rotary tool, a venturi part having a narrow passage section is formed in the main body, a speed adjusting shaft is fixed to one end of the rotor, and the shape can be displaced with respect to the speed adjusting shaft and the shape is closed at one end. The speed adjusting member is movable in the radial direction with respect to the rotation center axis of the speed adjusting shaft, the speed adjusting member is provided with a ball, and the speed adjusting member is adjusted with the centrifugal force applied to the ball. The displacement position of the speed adjusting member when the rotational speed of the rotor reaches the permissible rotational speed is displaced with respect to the axial direction of the rotation center axis of the shaft. Serial to narrow the cross-section of the air inlet passage between the tip and the venturi portion of the speed adjusting member so as to supply the amount of air speed does not exceed the allowable rotation speed of the rotor, the speed adjusting member A space is formed between the speed adjusting member and the tip of the speed adjusting shaft by the displacement, and the space and the air introduction passage are formed in a protruding portion formed on the tip closing side of the speed adjusting member. An apparatus for adjusting the rotational speed of an air rotary tool, characterized in that a penetrating small hole is formed . 前記貫通小孔の直径を０．５ｍｍ〜２ｍｍとしたことを特徴とする請求項１記載の空気回転工具の回転速度調節装置。Rotational speed adjusting device of the air rotary tool according to claim 1, characterized in that the diameter of the through small holes and 0.5 mm to 2 mm. 前記速度調節用部材が前記ボールと接触する面を、前記速度調節用部材の移動方向に対して傾斜した傾斜面とすることを特徴とする請求項１又は２記載の空気回転工具の回転速度調節装置。The surface on which the speed adjusting member is in contact with the ball, rotation speed adjustment of the air rotary tool according to claim 1 or 2, characterized in that an inclined surface inclined with respect to the moving direction of said speed adjusting member apparatus. 前記突出部と前記ベンチュリー部とで空気導入通路の狭い断面を形成することを特徴とする請求項１乃至３のいずれかに記載の空気回転工具の回転速度調節装置。The rotation speed adjusting device for an air rotary tool according to any one of claims 1 to 3 , wherein the protruding portion and the venturi portion form a narrow cross section of the air introduction passage. 前記突出部における先端部付近または軸方向全体に、先端に向けて先細りとなるテーパ部を形成したことを特徴とする請求項４記載の空気回転工具の回転速度調節装置。5. The rotational speed adjusting device for an air rotary tool according to claim 4 , wherein a taper portion tapering toward the tip is formed near the tip of the projecting portion or in the entire axial direction.
JP21416298A 1998-03-16 1998-07-29 Rotational speed adjustment device for pneumatic tool Expired - Fee Related JP4364323B2 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP21416298A JP4364323B2 (en) 1998-03-16 1998-07-29 Rotational speed adjustment device for pneumatic tool
US09/312,820 US6066033A (en) 1998-07-29 1999-05-17 Rotational speed adjusting device for a pneumatic rotational tool
DE19928987A DE19928987A1 (en) 1998-07-29 1999-06-24 Revolution number regulation unit for air rotation tool such as air grinder, air sanding machine
FR9908291A FR2781898B1 (en) 1998-07-29 1999-06-29 ROTATION SPEED ADJUSTMENT DEVICE FOR PNEUMATIC ROTARY TOOL

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP10-65026 1998-03-16
JP6502698 1998-03-16
JP21416298A JP4364323B2 (en) 1998-03-16 1998-07-29 Rotational speed adjustment device for pneumatic tool

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JPH11320455A JPH11320455A (en) 1999-11-24
JP4364323B2 true JP4364323B2 (en) 2009-11-18

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SE531610C2 (en) * 2007-12-20 2009-06-09 Atlas Copco Tools Ab A gas-powered rotary motor, a tool provided with a gas-powered rotary motor, and a method for controlling the rotational speed of a gas-powered rotary motor
JP2013144340A (en) * 2012-01-16 2013-07-25 Makita Corp Electric power tool
JP2013151055A (en) 2012-01-26 2013-08-08 Makita Corp Striking tool
JP6959641B2 (en) * 2017-11-20 2021-11-02 ヨコタ工業株式会社 Air motor governor and air tools
CN117117391B (en) * 2023-10-20 2024-01-26 珠海科创储能科技有限公司 Flow rate adjusting device and flow rate adjusting method

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