JP2017002951A - Torque limiter - Google Patents
Torque limiter Download PDFInfo
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- JP2017002951A JP2017002951A JP2015115443A JP2015115443A JP2017002951A JP 2017002951 A JP2017002951 A JP 2017002951A JP 2015115443 A JP2015115443 A JP 2015115443A JP 2015115443 A JP2015115443 A JP 2015115443A JP 2017002951 A JP2017002951 A JP 2017002951A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D43/00—Automatic clutches
- F16D43/02—Automatic clutches actuated entirely mechanically
- F16D43/20—Automatic clutches actuated entirely mechanically controlled by torque, e.g. overload-release clutches, slip-clutches with means by which torque varies the clutching pressure
- F16D43/21—Automatic clutches actuated entirely mechanically controlled by torque, e.g. overload-release clutches, slip-clutches with means by which torque varies the clutching pressure with friction members
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- Mechanical Engineering (AREA)
- One-Way And Automatic Clutches, And Combinations Of Different Clutches (AREA)
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Abstract
Description
本発明は、相対的に回転可能な内輪及び外輪と、両者の間に装着されるコイルばねとを備え、内輪と外輪とを相対的に回転させる回転トルクが所定値より大きいと、コイルばねによる摩擦力に打ち勝って外輪と内輪とが相対的に回転するトルクリミッタに関するものである。 The present invention includes a relatively rotatable inner ring and outer ring, and a coil spring mounted between the inner ring and the outer ring. When the rotational torque for relatively rotating the inner ring and the outer ring is greater than a predetermined value, the coil spring The present invention relates to a torque limiter in which the outer ring and the inner ring rotate relatively by overcoming the frictional force.
プリンタや複写機においては、上下方向に積層された用紙群から用紙を一枚ずつ給紙するための給紙装置が使用される。このような給紙装置にあっては、静電気のような微小相互吸着力によって複数の用紙が上下に吸着した重層状態で用紙群から用紙が取り出され、重層状態のまま用紙がプリンタや複写機の本体部に給紙されてしまうことがあり、これを回避するため、給紙装置には通常トルクリミッタが装着されている。 In printers and copiers, a paper feeding device is used to feed paper one by one from a group of sheets stacked in the vertical direction. In such a paper feeding device, the paper is taken out from the paper group in a multi-layer state in which a plurality of papers are adsorbed up and down by a minute mutual adsorption force such as static electricity, and the paper is left in the multi-layer state in a printer or a copier. In order to avoid this, the sheet feeding device is usually equipped with a torque limiter.
トルクリミッタを用いる給紙装置の一例として、特許文献1に開示されたものを図5に示す。給紙装置Sは、モーターのような適宜の駆動源に接続されて回転する駆動ローラーKRと、この駆動ローラーKRの回転軸と平行であって且つこの駆動ローラーKRの回転に従動して回転する従動ローラーJRと、用紙群を支持する用紙トレーPTとを有する。駆動ローラーKRと従動ローラーJRの表面は共に比較的摩擦係数が高く弾力性のある樹脂製素材で覆われており、駆動ローラーKRと従動ローラーJRとは、ばねのような適宜の付勢手段によって密着されている。そして、従動ローラーJRにはトルクリミッタTLが組み込まれている。 FIG. 5 shows an example of a paper feeder using a torque limiter, which is disclosed in Patent Document 1. The paper feeding device S is connected to an appropriate drive source such as a motor and rotates, and the drive roller KR rotates in parallel with the rotation axis of the drive roller KR and following the rotation of the drive roller KR. It has a driven roller JR and a paper tray PT that supports the paper group. The surfaces of the driving roller KR and the driven roller JR are both covered with a resin material having a relatively high coefficient of friction and elasticity, and the driving roller KR and the driven roller JR are made by appropriate biasing means such as a spring. It is in close contact. A torque limiter TL is incorporated in the driven roller JR.
積層された用紙群から給紙装置に用紙が一枚のみ給紙される場合においては、図5(a)に示すとおり、積層された用紙群の上面に位置する用紙と駆動ローラーKRとの表面摩擦力によって送り出された一枚の用紙Pが給紙装置Sに給紙され、駆動ローラーKRと従動ローラーJRに密接される。そして、反時計方向に回転する駆動ローラーKRと用紙Pの上面との摩擦力によって、用紙Pは駆動ローラーKRの回転方向に送り出され、従動ローラーJRは用紙Pを介して伝達される上記摩擦力によって時計方向に所定値より大きい回転トルクが付加されて従動回転する。
一方、用紙群から給紙装置に用紙が上下に重層された状態で給紙される場合においては、図5(b)に示すとおり、重層された用紙P1及びP2は重層状態のまま駆動ローラーKRの摩擦力によって給紙装置Sに給紙され、上側の用紙P1の上面には駆動ローラーKRが密接されると共に下側の用紙P2の下面には従動ローラーJRが密接される。そして、反時計方向に回転する駆動ローラーKRと上側の用紙P1との摩擦力によって上側の用紙P1は駆動ローラーKRの回転方向に送り出されようとする。しかしながら、上側の用紙P1と下側の用紙P2とは上記摩擦力に比べて小さい微小相互吸着力によって吸着しているにすぎず、上側の用紙P1に上記摩擦力が付加されると上側の用紙P1は下側の用紙P2から剥離され、上側の用紙P1と下側の用紙P2との間には滑りが生じる。そのため、従動ローラーJRには下側の用紙P2を介して所定値以下の比較的小さい回転トルクが付加されることとなる。かかる場合にあっては、従動ローラーJRはトルクリミッタTLによってその回転がロックされる。従動ローラーJRがロックすると、プリンタや複写機は運転を休止すると共に使用者に用紙が重層状態であることを報知し、重層した用紙の除去を促す。
When only one sheet is fed from the stacked sheet group to the sheet feeding device, as shown in FIG. 5A, the surface of the sheet positioned on the upper surface of the stacked sheet group and the driving roller KR. One sheet P sent out by the frictional force is fed to the sheet feeding device S and is brought into close contact with the driving roller KR and the driven roller JR. Then, the frictional force between the driving roller KR that rotates counterclockwise and the upper surface of the paper P causes the paper P to be fed in the rotational direction of the driving roller KR, and the driven roller JR transmits the frictional force via the paper P. As a result, a rotational torque larger than a predetermined value is applied in the clockwise direction and the driven rotation occurs.
On the other hand, when the sheets are fed from the sheet group to the sheet feeding device in the state where the sheets are stacked one above the other, as shown in FIG. 5B, the stacked sheets P1 and P2 remain in the stacked state and the driving roller KR. The driving roller KR is in close contact with the upper surface of the upper paper P1, and the driven roller JR is in close contact with the lower surface of the lower paper P2. The upper sheet P1 is about to be sent out in the rotation direction of the driving roller KR by the frictional force between the driving roller KR that rotates counterclockwise and the upper sheet P1. However, the upper sheet P1 and the lower sheet P2 are only adsorbed by a minute mutual adsorption force that is smaller than the frictional force. When the frictional force is applied to the upper sheet P1, the upper sheet P1 is adsorbed. P1 is peeled off from the lower sheet P2, and slippage occurs between the upper sheet P1 and the lower sheet P2. Therefore, a relatively small rotational torque of a predetermined value or less is applied to the driven roller JR via the lower sheet P2. In such a case, the rotation of the driven roller JR is locked by the torque limiter TL. When the driven roller JR is locked, the printer and the copying machine stop operating and inform the user that the paper is in a multi-layer state, and prompt the user to remove the multi-layer paper.
トルクリミッタは、給紙装置に限らず、駆動源のモーター等に過負荷が掛かったときに負荷を切り離してモーターを保護する部品としても用いられる。トルクリミッタとしては、例えば、特許文献2に記載された摩擦式のトルクリミッタが知られており、これの概要について図6を参照して説明する。
摩擦式のトルクリミッタは、軸状の内輪Nと、この内輪Nの外周面に一部が接触して装着され、摩擦力を付与するコイルばねBと、このコイルばねBが装着された上記内輪Nが挿入される筒状の外輪Gとを備えている。内輪Nは円筒形状であって、その外径は、自由状態(ばねに力が作用していない状態)におけるコイルばねBの接触部の径(図6の右側部分の径)よりも大きい。コイルばねBは、線材を巻回して形成され、その中心軸方向の先端には中心軸方向に延びる係合部K1が形成されていると共に、外輪Gの内側にはこの係合部K1と係合する被係合部K2が形成されている。なお、図6のコイルばねBには、内輪Nと接触しない大径部(図6の左側部分)が設けられているが、この部分は、トルクリミッタの基本的な機能には影響しない。
The torque limiter is not limited to the sheet feeding device, and is also used as a component for protecting the motor by cutting off the load when an overload is applied to the motor or the like of the drive source. As the torque limiter, for example, a friction type torque limiter described in Patent Document 2 is known, and an outline thereof will be described with reference to FIG.
The frictional torque limiter includes a shaft-shaped inner ring N, a coil spring B that is attached to a part of the outer peripheral surface of the inner ring N, and applies a frictional force, and the inner ring that is provided with the coil spring B. And a cylindrical outer ring G into which N is inserted. The inner ring N has a cylindrical shape, and its outer diameter is larger than the diameter of the contact portion of the coil spring B in the free state (the state where no force is applied to the spring) (the diameter of the right side portion in FIG. 6). The coil spring B is formed by winding a wire, and an engagement portion K1 extending in the central axis direction is formed at the tip in the central axis direction, and the engagement portion K1 is engaged inside the outer ring G. A mating engaged portion K2 is formed. In addition, although the large diameter part (left side part of FIG. 6) which does not contact the inner ring | wheel N is provided in the coil spring B of FIG. 6, this part does not affect the basic function of a torque limiter.
上述のとおり、図6に示すような摩擦式のトルクリミッタにおいては、内輪Nと外輪Gとを相対的に回転させる中心軸o周りの回転トルク(コイルばねBの内輪Nへの巻き付けを緩める方向に作用する回転トルク)が、内輪Nの外周面とコイルばねBとの内周面との間で生じる摩擦力よりも大きいときに、外輪Gと内輪Nとが相対的に回転して動力伝達が遮断される。例えば、内輪Nを駆動源のモーターに連結し外輪Gを負荷側に連結している場合には、相対的な回転によりモーターから負荷への最大の伝達トルク(空転トルク)が制限されるが、この際に、以下のような問題点がある。 As described above, in the frictional torque limiter as shown in FIG. 6, the rotational torque around the central axis o that relatively rotates the inner ring N and the outer ring G (the direction in which the winding of the coil spring B around the inner ring N is loosened). When the outer ring G and the inner ring N rotate relative to each other when the rotational torque) is greater than the frictional force generated between the outer peripheral surface of the inner ring N and the inner peripheral surface of the coil spring B. Is cut off. For example, when the inner ring N is connected to the motor of the drive source and the outer ring G is connected to the load side, the maximum transmission torque (idling torque) from the motor to the load is limited by relative rotation. At this time, there are the following problems.
空転トルクは、内輪Nの外周面とコイルばねBの内周面との間の摩擦力Fに、コイルばねBの内径Rを乗じた値(FR)に比例する。ここで、コイルばねBが接触する内輪Nの円周長さも内径Rに比例するから、コイルばねBが小径となるにつれて空転トルクは非常に小さくなる。小径のコイルばねBを用いて同一の空転トルクとするには、摩擦力Fを発生させるコイルばねBの締付力を大きくする必要があり、必然的にコイルばねBの応力が増加して許容応力を越える恐れが生じる。したがって、コイルばねBの小径化による摩擦式トルクリミッタの小型化には限界がある。
空転トルクを充分に大きくするために、複数個のコイルばねBを内輪Nと外輪Gとの間に装着することも考えられるが、この場合にはトルクリミッタの製造及び組み立て作業の効率が悪化すると共に、トルクリミッタが大型化してしまう。
本発明は、コイルばねを有する摩擦式のトルクリミッタにおける、このような問題点を解決することを課題とする。
The idling torque is proportional to a value (FR) obtained by multiplying the frictional force F between the outer peripheral surface of the inner ring N and the inner peripheral surface of the coil spring B by the inner diameter R of the coil spring B. Here, since the circumferential length of the inner ring N in contact with the coil spring B is also proportional to the inner diameter R, the idling torque becomes very small as the coil spring B becomes smaller in diameter. In order to achieve the same idling torque using the small-diameter coil spring B, it is necessary to increase the tightening force of the coil spring B that generates the frictional force F. There is a risk of exceeding stress. Therefore, there is a limit to downsizing the friction torque limiter by reducing the diameter of the coil spring B.
In order to sufficiently increase the idling torque, a plurality of coil springs B may be mounted between the inner ring N and the outer ring G. In this case, however, the efficiency of manufacturing and assembling the torque limiter deteriorates. At the same time, the torque limiter is enlarged.
An object of the present invention is to solve such a problem in a friction type torque limiter having a coil spring.
上記の課題に鑑み、本発明は、摩擦式のトルクリミッタのコイルばねを、軸方向の中央に外輪と係合する係合部を設けると共にこの係合部の両側に線材を巻回することにより形成し、この両側の線材を、軸方向の一方から見て反対方向に巻回するようにしたものである。すなわち、本発明は、
「軸状の内輪と、前記内輪の外周面に接触して装着され、線材を巻回して形成されるコイルばねと、前記コイルばねの装着された前記内輪が挿入される筒状の外輪とを備え、
前記内輪と前記外輪とは共通の中心軸を有し、前記コイルばねが前記外輪に相対回転不能に係合されており、
前記内輪と前記外輪とを相対的に回転させる前記中心軸周りの回転トルクが付加されたときは、前記回転トルクが所定値より大きい場合に、前記コイルばねと前記内輪との間の摩擦力に打ち勝って前記外輪と前記内輪とが相対的に回転するトルクリミッタであって、
前記コイルばねは、前記外輪と係合する係合部を備え、前記係合部の軸方向の両側に線材が巻回されており、前記両側の線材は、軸方向の一方から見て反対方向に巻回されている」
ことを特徴とするトルクリミッタとなっている。
In view of the above-described problems, the present invention provides a coil spring of a friction type torque limiter by providing an engaging portion that engages with an outer ring at the center in the axial direction and winding a wire around both sides of the engaging portion. The wire rods on both sides are wound in opposite directions when viewed from one side in the axial direction. That is, the present invention
"A shaft-shaped inner ring, a coil spring that is mounted in contact with the outer peripheral surface of the inner ring and wound with a wire, and a cylindrical outer ring into which the inner ring on which the coil spring is mounted is inserted. Prepared,
The inner ring and the outer ring have a common center axis, and the coil spring is engaged with the outer ring so as not to be relatively rotatable,
When a rotational torque around the central axis that relatively rotates the inner ring and the outer ring is added, the frictional force between the coil spring and the inner ring is increased when the rotational torque is greater than a predetermined value. A torque limiter that overcomes and relatively rotates the outer ring and the inner ring,
The coil spring includes an engaging portion that engages with the outer ring, and a wire rod is wound on both sides in the axial direction of the engaging portion, and the wire rods on both sides are in opposite directions when viewed from one of the axial directions. It is wound around. ''
The torque limiter is characterized by this.
本発明の摩擦式トルクリミッタは、線材を巻回して形成され、軸状の内輪の外周面に接触して装着されるコイルばねと、これらが挿入される筒状の外輪とを備える。内輪と外輪とは共通の中心軸を有し、コイルばねは外輪と相対回転不能に係合されており、内輪と外輪との間の回転トルクが所定値より大きい場合に、コイルばねと内輪との間の摩擦力に打ち勝って外輪と内輪とが相対的に回転する。トルクリミッタとしてのこうした基本的な構造及び機能は、従来のものと変わるわけではないが、本発明の摩擦式トルクリミッタにおいては、コイルばねを、軸方向の中央に外輪と係合する係合部を設け、この係合部の軸方向の両側で線材を巻回し、両側の線材を、軸方向の一方から見て反対方向に巻回するようにしている。コイルばねを反対方向に巻回したのは、コイルばねの巻き付けを緩める内輪の回転方向が、軸方向の一方から見たときは、係合部の両側に巻回されたコイルばね状の線材で互いに逆となるためである。 The friction type torque limiter of the present invention includes a coil spring that is formed by winding a wire and is in contact with the outer peripheral surface of a shaft-shaped inner ring, and a cylindrical outer ring into which these are inserted. The inner ring and the outer ring have a common central axis, the coil spring is engaged with the outer ring so as not to rotate relative to the outer ring, and when the rotational torque between the inner ring and the outer ring is greater than a predetermined value, the coil spring and the inner ring Overcoming the frictional force between the outer ring and the inner ring relatively rotate. Such a basic structure and function as a torque limiter is not different from the conventional one, but in the friction type torque limiter according to the present invention, the coil spring is engaged with the outer ring at the center in the axial direction. The wire rod is wound on both sides in the axial direction of the engaging portion, and the wire rods on both sides are wound in opposite directions when viewed from one side in the axial direction. The coil spring was wound in the opposite direction because the coil spring-like wire wound around both sides of the engaging part when the direction of rotation of the inner ring that loosens the coil spring was viewed from one side in the axial direction. This is because they are opposite to each other.
本発明のトルクリミッタにあっては、上述のとおり、係合部の両側に反対方向に巻回した線材が備えられ、これらによってコイルばねが形成される。このコイルばねは、外輪と係合する係合部の両側にそれぞれコイルばねを配置したものに相当し、コイルばねが内輪に及ぼす摩擦力は、両側に巻回された線材の摩擦力を合計したものとなる。したがって、摩擦力増大のために締付力を大きくする必要はないので、本発明の摩擦式トルクリミッタでは、コイルばねに発生する応力を増加することなく、大径のトルクリミッタと同等の空転トルクを得ることができる。
また、本発明のトルクリミッタでは、外輪と内輪とを相対的に回転させるトルクは、コイルばねの係合部から、両側に巻回された線材にそれぞれ均等に作用する。そのため、ばねの係合部付近においても、巻回された線材に確実に摩擦力が作用し、トルクリミッタとして安定した性能を発揮させることができる。これに対し、係合部の片側のみで内輪と接触させるコイルばねでは、係合部から離れた線材は内輪と接触するものの、係合部付近では、相対的な回転トルクによって内輪と線材が離れる現象が生じる。
In the torque limiter of the present invention, as described above, wire rods wound in opposite directions are provided on both sides of the engaging portion, and a coil spring is formed by these. This coil spring is equivalent to one in which coil springs are arranged on both sides of the engaging portion that engages with the outer ring, and the frictional force exerted on the inner ring by the coil spring is the sum of the frictional forces of the wire wound on both sides. It will be a thing. Therefore, since it is not necessary to increase the tightening force to increase the frictional force, the friction torque limiter of the present invention does not increase the stress generated in the coil spring, and the idling torque equivalent to that of the large-diameter torque limiter. Can be obtained.
In the torque limiter according to the present invention, the torque for relatively rotating the outer ring and the inner ring acts equally on the wire wound on both sides from the engaging portion of the coil spring. Therefore, even in the vicinity of the engaging portion of the spring, the frictional force acts on the wound wire surely, and a stable performance as a torque limiter can be exhibited. On the other hand, in the coil spring that is brought into contact with the inner ring only on one side of the engaging part, the wire separated from the engaging part comes into contact with the inner ring, but in the vicinity of the engaging part, the inner ring and the wire are separated by relative rotational torque. A phenomenon occurs.
本発明のトルクリミッタのコイルばねにおいて、外輪と係合する係合部を、線材をコの字形状に屈曲して形成したときは、両側に巻回される線材の間に、軸方向に延びる一定長さの直線状の線材が存在することとなる。コイルばねの係合部には、外輪と内輪とを相対的に回転させるトルクによる力が作用するが、その力は直線状の線材部分に分散されて作用するので、外輪との接触部分に及ぼす圧力は小さくなる。そのため、外輪の材料として合成樹脂等の硬度の小さいものを用いた場合であっても、コイルばねとの係合部分が損傷したり摩耗したりする不具合は回避される。
そして、コイルばねの係合部は、外輪と係合する関係上、線材が巻回される部分の巻回円よりも径方向の外方に延びる必要がある。線材に巻回などの加工を施して製造するコイルばねにおいて、係合部を、線材が巻回されたことにより形成された円の接線方向に延びるようにして形成するときは、その部分の加工が容易となる。
In the coil spring of the torque limiter of the present invention, when the engaging portion that engages with the outer ring is formed by bending the wire into a U-shape, it extends in the axial direction between the wires wound on both sides. There will be a linear wire of a certain length. A force by torque that relatively rotates the outer ring and the inner ring acts on the engaging portion of the coil spring, but the force acts on the linear wire portion so that it acts on the contact portion with the outer ring. The pressure becomes smaller. Therefore, even when a material having a low hardness such as a synthetic resin is used as the material of the outer ring, the problem that the engaging portion with the coil spring is damaged or worn is avoided.
And the engaging part of a coil spring needs to extend in the outward of radial direction rather than the winding circle | round | yen of the part by which a wire is wound, on the relationship engaged with an outer ring | wheel. In a coil spring manufactured by applying a process such as winding to a wire, when the engaging part is formed to extend in the tangential direction of a circle formed by winding the wire, the part is processed. Becomes easy.
本発明のトルクリミッタのコイルばねを、係合部の軸方向の両側で線材を同一数巻回して形成したときは、いわば2個の同一のコイルばね(要素)を背中合わせに配置した構造となる。つまり、係合部に対して対称的な構造となって、内輪に及ぼす摩擦力のバランスなどが良好となり、性能が安定したトルクリミッタを実現できる。 When the coil spring of the torque limiter according to the present invention is formed by winding the same number of wires on both sides in the axial direction of the engaging portion, the structure is such that two identical coil springs (elements) are arranged back to back. . That is, a torque limiter having a symmetrical structure with respect to the engaging portion, a good balance of frictional force exerted on the inner ring and the like, and a stable performance can be realized.
以下、図面に基づいて、本発明のトルクリミッタについて説明する。図1には、本発明のトルクリミッタの実施例の全体図を示し、その部品の単体図を図2乃至図4に示す。なお、図1は、外輪3とコイルばね4との係合部が分かるよう、外輪3の一部を破断して表したものである。 Hereinafter, the torque limiter of the present invention will be described with reference to the drawings. FIG. 1 shows an overall view of an embodiment of a torque limiter according to the present invention, and single parts of the components are shown in FIGS. FIG. 1 is a partially broken view of the outer ring 3 so that the engaging portion between the outer ring 3 and the coil spring 4 can be seen.
図1に示すように、全体を符号1で示す本実施例のトルクリミッタは、内輪2と外輪3とコイルばね4とを備えている。内輪2は、コイルばね4を外周に装着した状態で、外輪3の円筒状の空洞部に挿入される。内輪2と外輪3は、共通の中心軸oを有し、相対的に回転可能に構成されている。 As shown in FIG. 1, the torque limiter of this embodiment, indicated as a whole by reference numeral 1, includes an inner ring 2, an outer ring 3, and a coil spring 4. The inner ring 2 is inserted into the cylindrical cavity of the outer ring 3 with the coil spring 4 mounted on the outer periphery. The inner ring 2 and the outer ring 3 have a common center axis o and are configured to be relatively rotatable.
図1と共に図2を参照して説明すると、内輪2は、中心軸oを備えた軸状の部品であって、コイルばね4が装着される大径部21と、この大径部21の先端側(便宜上、図の右側を前方、左側を後方とする。)に形成された小径部22と、大径部21及び小径部22の中間に形成されたテーパー部23とを有する。本実施例では、内輪2は、鋼材を鍛造することにより成形されている。 Referring to FIG. 2 together with FIG. 1, the inner ring 2 is a shaft-like component having a central axis o, and has a large-diameter portion 21 to which the coil spring 4 is attached, and a tip of the large-diameter portion 21. A small-diameter portion 22 formed on the side (for the sake of convenience, the right side in the drawing is the front and the left side is the rear), and the tapered portion 23 formed between the large-diameter portion 21 and the small-diameter portion 22. In the present embodiment, the inner ring 2 is formed by forging a steel material.
内輪2の大径部21は円柱形状であり、小径部22も全体として円柱形状である。テーパー部23は、その断面の径が後方端から前方端に向かって次第に小さくなる円錐台形状であり、その後方端は大径部21に接続され、前方端は小径部22に接続されている。ここで、大径部21の径は自由状態のコイルばね4の内径よりも大きく、小径部22の径は自由状態のコイルばね4の内径よりも小さく設定されており、したがって、テーパー部23は、その最小径が自由状態のコイルばね4の内径よりも小さく、最大径が自由状態のコイルばね4の内径よりも大きい。このようなテーパー部23を大径部21と小径部22との間に設けることにより、コイルばね4を大径部21に装着する際に、特殊な治具を用いることなく、内輪2を単に押圧して自由状態のコイルばね4の内径を拡げながら大径部21に装着することが可能となる。
小径部22の先端部には、後述する外輪3に形成される内向き突起部が嵌まり込む段付き溝部24が形成されている。段付き溝部24は小径部22の外周面に全周に亘り形成される。大径部21の後端には円環形状の鍔部25が形成され、鍔部25の後端面には、円柱形状の外周の一部が切り欠かれた連結部26が形成されている。
The large diameter portion 21 of the inner ring 2 has a cylindrical shape, and the small diameter portion 22 also has a cylindrical shape as a whole. The tapered portion 23 has a truncated cone shape in which the diameter of the cross section gradually decreases from the rear end toward the front end, the rear end is connected to the large diameter portion 21, and the front end is connected to the small diameter portion 22. . Here, the diameter of the large diameter portion 21 is set to be larger than the inner diameter of the coil spring 4 in the free state, and the diameter of the small diameter portion 22 is set to be smaller than the inner diameter of the coil spring 4 in the free state. The minimum diameter is smaller than the inner diameter of the coil spring 4 in the free state, and the maximum diameter is larger than the inner diameter of the coil spring 4 in the free state. By providing such a tapered portion 23 between the large-diameter portion 21 and the small-diameter portion 22, when the coil spring 4 is attached to the large-diameter portion 21, the inner ring 2 is simply used without using a special jig. It is possible to mount the coil spring 4 on the large-diameter portion 21 while expanding the inner diameter of the coil spring 4 in a free state.
A stepped groove portion 24 into which an inward projection formed on the outer ring 3 to be described later is fitted is formed at the distal end portion of the small diameter portion 22. The stepped groove portion 24 is formed on the outer peripheral surface of the small diameter portion 22 over the entire circumference. An annular flange 25 is formed at the rear end of the large-diameter portion 21, and a connecting portion 26 is formed on the rear end surface of the flange 25 with a part of the outer periphery of the columnar shape cut out.
図1と共に図3を参照して説明すると、外輪3は、中心軸oを中心とする筒状部材であって、比較的外径の大きい後方部31と比較的外径の小さい前方部32とを有する。本実施例では、外輪3は、例えばポリアセタールなどの熱可塑性樹脂を射出成型することにより成形される。 Referring to FIG. 3 together with FIG. 1, the outer ring 3 is a cylindrical member centered on the central axis o, and includes a rear portion 31 having a relatively large outer diameter and a front portion 32 having a relatively small outer diameter. Have In this embodiment, the outer ring 3 is formed by injection molding a thermoplastic resin such as polyacetal.
外輪3の後方部31の内側には、第1の空洞部311が形成されている。第1の空洞部311の内径は上述した内輪2の円環形状鍔部25が収容される程度に大きい。第1の空洞部311の前方には、第2の空洞部312が形成されている。第2の空洞部312は、コイルばね4を装着した状態の内輪2の大径部21を収容する部分であって、第2の空洞部312の内径は第1の空洞部311の直径よりも小さい。
そして、後方部31の周方向における所定角度位置には、後方部31の後端から軸方向中間位置より幾分前方の位置まで直線状に延在するスリット33が設けられており、図3の右側面図から分かるとおり、このスリット33は、後方部31の内側面から外側面まで垂直方向に形成されている。
A first cavity 311 is formed inside the rear portion 31 of the outer ring 3. The inner diameter of the first cavity portion 311 is large enough to accommodate the above-described annular flange portion 25 of the inner ring 2. A second cavity 312 is formed in front of the first cavity 311. The second cavity portion 312 is a portion that accommodates the large-diameter portion 21 of the inner ring 2 in a state where the coil spring 4 is mounted, and the inner diameter of the second cavity portion 312 is larger than the diameter of the first cavity portion 311. small.
A slit 33 extending linearly from the rear end of the rear portion 31 to a position somewhat ahead of the axial intermediate position is provided at a predetermined angular position in the circumferential direction of the rear portion 31. As can be seen from the right side view, the slit 33 is formed in the vertical direction from the inner surface to the outer surface of the rear portion 31.
外輪3の前方部32の内側には、円柱形状の第3の空洞部313が形成されると共に、第3の空洞部313の前方には、全体として円柱形状の第4の空洞部314が形成されている。第3の空洞部313の内径は内輪2の大径部21と等しく、また、第4の空洞部314の内径は内輪2の小径部22と等しく設定されている。したがって、これらの空洞部には、内輪2の大径部21及び小径部22を隙間なく嵌め込むことができる。そして、第4の空洞部314の前方端部における内周面には、内輪2の段付き溝部24に嵌まり込む内向き突起部315が形成されている。
トルクリミッタ1の組み立て時には、予めコイルばね4が装着された内輪2を外輪3の後端側(第1の空洞部311側)から挿入する。挿入の際は、コイルばね4の係合部41と外輪3のスリット33との周方向位置を整合させて行い、組み立て後には、図1に示すとおり、コイルばね4の係合部41がスリット33の端部に突き当たるとともに、内輪2の段付き溝部24に外輪3の内向き突起部316が嵌め込まれる。組み立て時には、コイルばね4にグリースなどの潤滑剤を塗布することが好ましい。
A cylindrical third cavity 313 is formed inside the front portion 32 of the outer ring 3, and a generally fourth cylindrical cavity 314 is formed in front of the third cavity 313. Has been. The inner diameter of the third cavity portion 313 is set equal to the large diameter portion 21 of the inner ring 2, and the inner diameter of the fourth cavity portion 314 is set equal to the small diameter portion 22 of the inner ring 2. Therefore, the large-diameter portion 21 and the small-diameter portion 22 of the inner ring 2 can be fitted into these hollow portions without any gap. An inward projection 315 that fits into the stepped groove 24 of the inner ring 2 is formed on the inner peripheral surface at the front end of the fourth cavity 314.
When the torque limiter 1 is assembled, the inner ring 2 on which the coil spring 4 has been mounted in advance is inserted from the rear end side (first cavity 311 side) of the outer ring 3. During insertion, the circumferential positions of the engaging portion 41 of the coil spring 4 and the slit 33 of the outer ring 3 are aligned, and after assembly, the engaging portion 41 of the coil spring 4 is slit as shown in FIG. While striking the end of 33, the inward projection 316 of the outer ring 3 is fitted into the stepped groove 24 of the inner ring 2. At the time of assembly, it is preferable to apply a lubricant such as grease to the coil spring 4.
ここで、本発明の摩擦式トルクリミッタの特徴的な構造であるコイルばね4について、図1と共に図4を参照して説明する。金属製のコイルばね4は、一般的なばね鋼等の線材に巻き加工等を施して形成したものであって、外輪3のスリット33と係合する係合部41を備え、係合部41の軸方向の両側に線材Lが巻回されている。この両側の線材Lは、軸方向の一方から見て反対方向に同一回数巻かれている。すなわち、図4の実施形態おいては、コイルばね4の線材Lは、正面図の右方から見て、係合部41の右側の線材Lが時計方向に巻回されている(図4の右側面図参照)が、係合部41で折り返すようにして、左側の線材Lが反時計方向に巻回されている。これにより、図1のようにコイルばね4を内輪2の外周面に装着したときは、内輪2に右方から見て時計方向の回転トルクが作用した場合に、コイルばね4の巻き付けが緩むこととなる。 Here, the coil spring 4 which is a characteristic structure of the friction type torque limiter of the present invention will be described with reference to FIG. 4 together with FIG. The coil spring 4 made of metal is formed by winding a common wire such as spring steel, and includes an engagement portion 41 that engages with the slit 33 of the outer ring 3. The wire L is wound on both sides in the axial direction. The wire L on both sides is wound the same number of times in the opposite direction when viewed from one side in the axial direction. That is, in the embodiment of FIG. 4, the wire L of the coil spring 4 is wound clockwise in the clockwise direction when viewed from the right side of the front view (see FIG. 4). The left wire L is wound counterclockwise so that the engagement portion 41 is folded back (see the right side view). As a result, when the coil spring 4 is mounted on the outer peripheral surface of the inner ring 2 as shown in FIG. 1, the winding of the coil spring 4 is loosened when a clockwise rotational torque is applied to the inner ring 2 as viewed from the right. It becomes.
図4の実施形態のコイルばね4は、一本の線材Lを連続的に加工して製造されており、外輪3のスリット33に係合する係合部41は、線材Lをコの字形状に屈曲することで形成されている。係合部41には、軸方向に延びる直線部分が存在し、この直線部分が全体的にスリット33と接触するので、接触部分の圧力を低下することができる。また、係合部41は、図4の右側面図に示すとおり、線材Lが巻回されたことにより形成された円の接線方向上方に延びている。一本の線材Lにこのような加工を施して係合部41を形成することで、係合部41として追加部品を別途設ける必要がなく、コイルばね4の製造コストを低減させることができる。 The coil spring 4 of the embodiment of FIG. 4 is manufactured by continuously processing a single wire L, and the engaging portion 41 that engages with the slit 33 of the outer ring 3 has a U-shape. It is formed by bending. The engaging portion 41 has a linear portion extending in the axial direction, and the linear portion entirely contacts the slit 33, so that the pressure at the contact portion can be reduced. Further, as shown in the right side view of FIG. 4, the engaging portion 41 extends upward in the tangential direction of a circle formed by winding the wire L. By forming the engaging portion 41 by performing such processing on one wire L, it is not necessary to separately provide an additional part as the engaging portion 41, and the manufacturing cost of the coil spring 4 can be reduced.
次いで、上述の本発明のトルクリミッタの作動について、図1を参照して説明する。
内輪2と外輪3とを相対的に回転させる中心軸oの軸周りに所定値よりも大きい回転トルク、つまり空転トルクが、コイルばね4の内輪2への巻き付けを緩める方向に付加されると、コイルばね4の締付力によるコイルばね4と内輪2との間の摩擦力に打ち勝ち、外輪3と内輪2とが相対的に回転する。一方、空転トルク以下であれば、内輪2とコイルばね4との間の摩擦力により、相対的な回転は生じない。
本発明のトルクリミッタ1では、コイルばね4の係合部41の両側に反対方向に同一数巻回した線材が備えられており、コイルばね4の締付力が内輪2に及ぼす摩擦力は、両側に巻回された線材の摩擦力を合計したものとなる。そのため、従来の摩擦式トルクリミッタのように、係合部の片側に線材を巻回したものと比較すると、コイルばね4の締付力が同一の場合であっても、ほぼ2倍の空転トルクを得ることができる。また、外輪3と内輪2とを相対的に回転させるトルクは、コイルばね4の係合部41から両側に巻回された線材にそれぞれ均等に作用するため、係合部41付近においても巻回された線材に確実に摩擦力が作用し、トルクリミッタとして安定した性能を発揮できる。
Next, the operation of the torque limiter of the present invention will be described with reference to FIG.
When a rotational torque greater than a predetermined value, that is, an idling torque, is applied in a direction to loosen the winding of the coil spring 4 around the inner ring 2 around the central axis o that relatively rotates the inner ring 2 and the outer ring 3. The friction force between the coil spring 4 and the inner ring 2 due to the tightening force of the coil spring 4 is overcome, and the outer ring 3 and the inner ring 2 rotate relatively. On the other hand, if it is equal to or less than the idling torque, relative rotation does not occur due to the frictional force between the inner ring 2 and the coil spring 4.
In the torque limiter 1 of the present invention, the wire rod wound in the opposite direction on both sides of the engaging portion 41 of the coil spring 4 is provided, and the frictional force exerted on the inner ring 2 by the tightening force of the coil spring 4 is It is the sum of the frictional forces of the wire wound on both sides. Therefore, as compared with a conventional friction torque limiter in which a wire is wound around one side of the engaging portion, even if the tightening force of the coil spring 4 is the same, the idling torque is almost doubled. Can be obtained. In addition, the torque that relatively rotates the outer ring 3 and the inner ring 2 acts equally on the wire wound on both sides from the engaging portion 41 of the coil spring 4, so that the winding is also performed in the vicinity of the engaging portion 41. A frictional force acts reliably on the wire thus obtained, and can exhibit stable performance as a torque limiter.
空転トルク以上のトルクが作用して内輪2と外輪3とが相対的に回転する場合、本発明のトルクリミッタ1では、第3の空洞部313の内径は内輪2の大径部21と等しく、第4の空洞部314の内径は内輪2の小径部22と等しく設定されていて、内輪2と外輪3の回転軸の「ぶれ」が防止される。第2の空洞部312内では、コイルばね4の係合部41の両側に線材Lが巻回されており、内輪2が係合部41の両側で支持されるので、コイルばね4に対する内輪2の回転が円滑になる。さらに、外輪3の突起部315が内輪2の先端部の段付き溝部24に嵌り込むことで、内輪2と外輪3の相対的な軸方向への移動が防止される。 When the inner ring 2 and the outer ring 3 are rotated relative to each other when a torque greater than the idling torque is applied, the inner diameter of the third cavity 313 is equal to the large-diameter portion 21 of the inner ring 2 in the torque limiter 1 of the present invention. The inner diameter of the fourth cavity portion 314 is set equal to the small diameter portion 22 of the inner ring 2, and “blurring” of the rotation shafts of the inner ring 2 and the outer ring 3 is prevented. In the second cavity 312, the wire L is wound on both sides of the engaging portion 41 of the coil spring 4, and the inner ring 2 is supported on both sides of the engaging portion 41. The rotation becomes smooth. Further, the protrusion 315 of the outer ring 3 is fitted into the stepped groove 24 at the tip of the inner ring 2, so that the inner ring 2 and the outer ring 3 are prevented from moving in the relative axial direction.
以上、本発明のトルクリミッタの好適な実施形態について詳述した。上記の実施形態においては、内輪を鍛造により製作しているが、焼結やプレス等で製造できるのは言うまでもない。また、コイルばねの係合部を、線材が巻回されたことにより形成された縁の接線方向に延びるようにすることに替えて、線材が巻回されたことにより形成された縁の法線方向に延びるようにしてもよい。この場合にあっては、外輪に設けられるスリットは径方向に延在することとなる。このように、上記の実施形態を適宜変更することができるのは明らかである。 The preferred embodiment of the torque limiter of the present invention has been described in detail above. In the above embodiment, the inner ring is manufactured by forging, but it goes without saying that it can be manufactured by sintering or pressing. In addition, instead of extending the engaging portion of the coil spring in the tangential direction of the edge formed by winding the wire, the normal of the edge formed by winding the wire You may make it extend in the direction. In this case, the slit provided in the outer ring extends in the radial direction. Thus, it is obvious that the above embodiment can be modified as appropriate.
1:トルクリミッタ
2:内輪
3:外輪
33:スリット
4:コイルばね
41:係合部
1: Torque limiter 2: Inner ring 3: Outer ring 33: Slit 4: Coil spring 41: Engagement part
Claims (4)
前記内輪と前記外輪とは共通の中心軸を有し、前記コイルばねが前記外輪に相対回転不能に係合されており、
前記内輪と前記外輪とを相対的に回転させる前記中心軸周りの回転トルクが付加されたときは、前記回転トルクが所定値より大きい場合に、前記コイルばねと前記内輪との間の摩擦力に打ち勝って前記外輪と前記内輪とが相対的に回転するトルクリミッタであって、
前記コイルばねは、前記外輪と係合する係合部を備え、前記係合部の軸方向の両側に線材が巻回されており、前記両側の線材は、軸方向の一方から見て反対方向に巻回されている、ことを特徴とするトルクリミッタ。 A shaft-shaped inner ring; a coil spring that is mounted in contact with the outer peripheral surface of the inner ring and wound with a wire; and a cylindrical outer ring into which the inner ring on which the coil spring is mounted is inserted. ,
The inner ring and the outer ring have a common center axis, and the coil spring is engaged with the outer ring so as not to be relatively rotatable,
When a rotational torque around the central axis that relatively rotates the inner ring and the outer ring is added, the frictional force between the coil spring and the inner ring is increased when the rotational torque is greater than a predetermined value. A torque limiter that overcomes and relatively rotates the outer ring and the inner ring,
The coil spring includes an engaging portion that engages with the outer ring, and a wire rod is wound on both sides in the axial direction of the engaging portion, and the wire rods on both sides are in opposite directions when viewed from one of the axial directions. A torque limiter wound around
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JP5445900B2 (en) * | 2008-10-08 | 2014-03-19 | Ntn株式会社 | Torque limiter |
-
2015
- 2015-06-08 JP JP2015115443A patent/JP6355596B2/en active Active
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2016
- 2016-06-07 CN CN201610396680.2A patent/CN106246760B/en active Active
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US4869357A (en) * | 1988-07-28 | 1989-09-26 | Batchelder James W | Overrunning clutch with grooved bushing for reception of spring coil |
JPH07293577A (en) * | 1994-04-27 | 1995-11-07 | Ntn Corp | Spring clutch |
JPH08338441A (en) * | 1995-06-09 | 1996-12-24 | Toyota Autom Loom Works Ltd | Overload preventer |
JPH09112568A (en) * | 1995-10-18 | 1997-05-02 | Origin Electric Co Ltd | Torque limiter and clutch |
JP2014185677A (en) * | 2013-03-22 | 2014-10-02 | Suncall Corp | Torque limiter |
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CN106246760B (en) | 2019-12-10 |
CN106246760A (en) | 2016-12-21 |
JP6355596B2 (en) | 2018-07-11 |
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