JP4558474B2

JP4558474B2 - Torque limiter

Info

Publication number: JP4558474B2
Application number: JP2004362804A
Authority: JP
Inventors: 正明本多; 貴志山本
Original assignee: NTN Corp
Current assignee: NTN Corp
Priority date: 2004-12-15
Filing date: 2004-12-15
Publication date: 2010-10-06
Anticipated expiration: 2024-12-15
Also published as: CN1789744A; CN1789743A; JP2006170307A; CN1789744B; CN100510451C

Description

この発明は、プリンタ、複写機等の事務機に使用されるばね式トルクリミッタに関し、特にバックラッシの解消を図ったものである。 The present invention relates to a spring-type torque limiter used in office machines such as printers and copiers, and particularly aims to eliminate backlash.

事務機等に用いられるばね式トルクリミッタとして従来から知られているものは、図７に示したように、外環部材４１と、その内部に挿入され一端部のボス部４２において相対回転可能に支持された内輪４３と、該内輪４３の外径面に所要の締め代で装着されたコイルばね４４と、前記外環部材４１の他端部においてその内径面に嵌合固定され内輪４３の外径面との間を閉塞するとともに内輪４３を回転自在に支持する蓋部材４９とからなる。前記コイルばね４４は大径部４４ａと小径部４４ｂを有し、その小径部４４ｂを前記内輪４３の外径面に所要の締め代で緊縛させている。該小径部４４ｂの端部にアキシャル方向に屈曲したフック４５が設けられ、これを前記外環部材４１のボス部４２に係合させている。また大径部４４ａの端部にもアキシャル方向に屈曲したフック４６が設けられ、これを蓋部材４９に係合させている（特許文献１参照）。 As shown in FIG. 7, a conventionally known spring-type torque limiter used in office machines or the like is relatively rotatable at an outer ring member 41 and a boss portion 42 at one end inserted therein. A supported inner ring 43, a coil spring 44 attached to the outer diameter surface of the inner ring 43 with a required tightening allowance, and an outer ring member 41 fitted and fixed to the inner diameter surface of the other end of the outer ring member 41. It comprises a lid member 49 that closes the radial surface and rotatably supports the inner ring 43. The coil spring 44 has a large-diameter portion 44a and a small-diameter portion 44b, and the small-diameter portion 44b is fastened to the outer-diameter surface of the inner ring 43 with a required tightening margin. A hook 45 bent in the axial direction is provided at the end of the small-diameter portion 44b, and is engaged with the boss portion 42 of the outer ring member 41. A hook 46 bent in the axial direction is also provided at the end of the large-diameter portion 44a, and is engaged with a lid member 49 (see Patent Document 1).

上記のトルクリミッタ４０は、内輪４３と外環部材４１の相対回転により、フック４５側から見てコイルばね４４がその巻き方向に回転すると、小径部４４ｂにおいて拡径作用が生じ一定の大きさのトルク、即ち、規定トルク値を発生させる。前記と反対方向に回転させた場合は小径部４４ｂにおいて縮径作用が生じ内輪４３がロックするので、この場合はトルクリミッタとしての機能は果たし得ない。即ち、一方向トルクリミッタとしての作用を行う。 The above torque limiter 40, by the relative rotation of the inner ring 43 and outer ring member 41, the coil spring 44 as viewed from the hook 45 side is rotating in the winding direction, the constant occurs expanded activity in the small diameter portion 44b size Torque, that is, a prescribed torque value is generated. When rotated in the opposite direction, a diameter reducing action occurs in the small diameter portion 44b and the inner ring 43 is locked. In this case, the function as a torque limiter cannot be achieved. That is, it acts as a one-way torque limiter.

前記の規定トルク値の大きさの調整は、外環部材４１を固定して蓋部材４９を所要の工具を用いて外部から回転させると、コイルばね４４の大径部４４ａを経て小径部４４ｂの締め代が変化するのでこれにより規定トルク値が調整される。 When the outer ring member 41 is fixed and the lid member 49 is rotated from the outside using a required tool, the regulation torque value is adjusted by passing the large diameter portion 44a of the coil spring 44 through the large diameter portion 44b. Since the tightening allowance changes, the specified torque value is adjusted accordingly.

上記のトルクリミッタ４０は、例えば、事務機等の紙さばきローラ４７（図７、図８参照）の一端部に外環部材４１のボス部４２側の端部を連結することにより使用に供される。紙さばきローラ４７に作用する負荷トルクがトルクリミッタ４０の規定トルク値以上であるときは、トルクリミッタ４０の外環部材４１が負荷側（図８に示した給紙ローラ４８）から回転され（矢印ａ参照）シート紙５０を送り出すが、シート紙５０の重送が発生すると重送に伴う摩擦の低下によって負荷トルクがトルクリミッタ４０の規定トルク値より軽くなる。このため、外環部材４１と紙さばきローラ４７は、軸５１に取り付けられた内輪４３側からコイルばね４４を介して逆方向に回転され（図８の一点鎖線矢印ｂ参照）、紙さばきローラ４７に接したシート紙５０を押し戻して重送を解消する。 The torque limiter 40 is used, for example, by connecting an end portion of the outer ring member 41 on the boss portion 42 side to one end portion of a paper separating roller 47 (see FIGS. 7 and 8) of an office machine or the like. The When the load torque acting on the paper separating roller 47 is equal to or greater than the specified torque value of the torque limiter 40, the outer ring member 41 of the torque limiter 40 is rotated from the load side (the feed roller 48 shown in FIG. 8) (arrow). (Refer to a) The sheet paper 50 is sent out. When the double feeding of the sheet paper 50 occurs, the load torque becomes lighter than the specified torque value of the torque limiter 40 due to the decrease in friction caused by the double feeding. For this reason, the outer ring member 41 and the paper separating roller 47 are rotated in the reverse direction via the coil spring 44 from the side of the inner ring 43 attached to the shaft 51 (see the dashed line arrow b in FIG. 8), and the paper separating roller 47 The sheet paper 50 in contact with the sheet is pushed back to eliminate double feeding.

前記のような小径コイル部４４ａと大径コイル部４４ｂからなる２段径のコイルばね４４を使用したトルクリミッタのほかに、単一径のコイルばねを使用したものも知られている（特許文献２、同３参照）。特許文献２の場合のコイルばねは、その両端部にラジアル方向外向きに突き出したフックが形成され、そのフックが外環部材に係合される。また、特許文献３の場合のコイルばねは、フックが両端部においてアキシャル方向に突き出して形成され、そのフックが外環部材に係合される。
特開平８−２７０６７３号公報（「実施例」、図１、図２）特開平１０−１１０７３９号公報（「発明を実施するための態様」、図１）特開平１１−２５７３６８号公報（「発明の実施の形態」、図１、図２） In addition to the torque limiter using the two-stage coil spring 44 composed of the small-diameter coil portion 44a and the large-diameter coil portion 44b as described above, there is also known one using a single-diameter coil spring (Patent Literature). 2, see 3). In the coil spring of Patent Document 2, hooks protruding outward in the radial direction are formed at both ends, and the hooks are engaged with the outer ring member. Further, the coil spring in the case of Patent Document 3 is formed such that the hook protrudes in the axial direction at both ends, and the hook is engaged with the outer ring member.
JP-A-8-270673 ("Example", FIGS. 1 and 2) Japanese Patent Laid-Open No. 10-110739 ("Mode for carrying out the invention", FIG. 1) Japanese Patent Laid-Open No. 11-257368 ("Embodiments of the Invention", FIGS. 1 and 2)

前記のようなコイルばねを使用したトルクリミッタにおける問題点を図９に基づいて説明する。図９は図７における断面図であり、コイルばね４４は右巻きである。外環部材４１が固定された状態で内輪４３がその巻き方向と反対方向（矢印Ａ参照）に回転した場合について見ると、フック４５の部分が外環部材４１に固定されているため、コイルばね４４（小径部４４ｂ）に拡径作用が発生し、内輪４３は一定のトルクをもって外環部材４１に対して回転する。この場合のコイルばね４４の拡径作用を微視的に見ると、内輪４３に回転力が加わった当初において、コイルばね４４のフック４５近傍のばね端部には、一点鎖線で示すような拡径方向に膨出する撓み５２が一時的に発生する。その時点においてはコイルばね４４の他のコイル部分の内輪４３に対する締め代には実質的な変化は生じていないので内輪４３はロック状態にある。前記の撓み５２を発生させる内部応力が締め代による締め付け力を超えると、その応力がコイルばね全体に拡散し、撓み５２が消失するとともにコイルばね４４の全体に拡径作用が波及するため、内輪４３が一定のトルクをもって回転する。即ち、コイルばね４４の拡径作用によってトルクを発生させ、トルクリミッタとしての作用を行う。 Problems in the torque limiter using the coil spring as described above will be described with reference to FIG. FIG. 9 is a cross-sectional view in FIG. 7, and the coil spring 44 is right-handed. When the outer ring member 41 is fixed and the inner ring 43 rotates in the direction opposite to the winding direction (see arrow A), the portion of the hook 45 is fixed to the outer ring member 41. 44 (small diameter portion 44b) is expanded, and the inner ring 43 rotates with respect to the outer ring member 41 with a constant torque. When the diameter expansion action of the coil spring 44 in this case is viewed microscopically, at the beginning when the rotational force is applied to the inner ring 43, the spring end near the hook 45 of the coil spring 44 is expanded as shown by a one-dot chain line. A flexure 52 bulging in the radial direction is temporarily generated. At that time, the inner ring 43 is in a locked state because there is no substantial change in the tightening allowance of the other coil portion of the coil spring 44 with respect to the inner ring 43. When the internal stress that generates the deflection 52 exceeds the tightening force due to the tightening allowance, the stress is diffused throughout the coil spring, and the deflection 52 disappears and a diameter expanding action is spread over the entire coil spring 44. 43 rotates with a constant torque. That is, torque is generated by the diameter-expanding action of the coil spring 44, and acts as a torque limiter.

上記のように内輪４３と外環部材４１の相対回転によるトルク発生の初期において、コイルばね４４に部分的な撓み５２が発生し、それが消失するまでの間は内輪４３又は外環部材４１が回転できない状態にある。即ち、回転力の入力からトルク発生までの間に時間的な遅れ、即ちバックラッシが生じることになる。バックラッシが生じると、前記の紙さばきローラ４７に使用された場合においては紙さばきのタイミングがずれてしまうといった問題が発生する。 As described above, at the initial stage of torque generation due to the relative rotation of the inner ring 43 and the outer ring member 41, a partial deflection 52 occurs in the coil spring 44, and the inner ring 43 or the outer ring member 41 remains until it disappears. It cannot be rotated. That is, a time delay, that is, backlash occurs between the input of the rotational force and the generation of torque. When backlash occurs, there arises a problem that the timing of paper separation is shifted when the paper separation roller 47 is used.

前記のバックラッシは、コイルばねが２段径の場合でなく、特許文献２、３の単一径の場合においても同様の原因により起こり得る。 The backlash can occur not only in the case where the coil spring has a two-stage diameter but also in the case of the single diameter in Patent Documents 2 and 3 due to the same cause.

一方、前記の各特許文献に示されたトルクリミッタのコイルばねは、いずれもその両端部に径方向又は軸方向に屈曲されたフック（例えば、図７の場合のフック４５、４６参照）が設けられるが、これらのフックはトルクリミッタの小型化の妨げになるとともに、組み立て時においてフックを外環部材等の係合穴を目掛けて差し込む作業が必要となり、作業性が阻害される要因になる。 On the other hand, each of the coil springs of the torque limiter shown in each of the above patent documents is provided with hooks bent in the radial direction or the axial direction at both ends (for example, see hooks 45 and 46 in the case of FIG. 7). However, these hooks hinder the miniaturization of the torque limiter, and it is necessary to insert the hooks through the engagement holes of the outer ring member or the like at the time of assembly, which is a factor that hinders workability. .

このため、図１０（ａ）（ｂ）に示したトルクリミッタ４０’のように、コイルばね４４を単一径で形成するとともに、その両端部はコイル形状を保持したままで切断しただけの端部（ストレート端部４５’、４６’と称する。）に形成し、これらのストレート端部４５’、４６’をそれぞれ外環部材４１の突部５３と蓋部材４９の突部５４の側面に当てる構成が考えらえる。 Therefore, as in the torque limiter 40 ′ shown in FIGS. 10A and 10B, the coil spring 44 is formed with a single diameter, and both ends of the coil spring 44 are simply cut while maintaining the coil shape. The straight end portions 45 ′ and 46 ′ are respectively applied to the side surfaces of the protrusion 53 of the outer ring member 41 and the protrusion 54 of the lid member 49. The configuration can be considered.

この構成は、トルクリミッタの小型化、作業性の改善の観点から望ましい対策であるが、この場合もトルク発生の初期において突部５３（５４）に当ったストレート端部４５’（４６’）において撓みが発生するため、前記の場合と同様にバックラッシが発生する問題がある。 This configuration is a desirable measure from the viewpoint of downsizing the torque limiter and improving workability, but in this case as well, at the straight end 45 ′ (46 ′) that hits the protrusion 53 (54) in the initial stage of torque generation. Since bending occurs, there is a problem that backlash occurs as in the case described above.

また、次のような問題もある。即ち、図１１に示したように、ストレート端部４５’（４６’）をもったコイルばね４４を内輪４３に一定の締め代をもって装着した場合、ストレート端部４５’（４６’）においてはその自由状態のときの曲率半径をもって湾曲したまま内輪４３に巻き付き、その切断端５５が内輪４３の外径面に対し突き当たる。コイルばね４４剛性が低い場合はこのようなことはなく、ストレート端部４５’（４６’）は弾性変形して内輪４３の外径面に密着するが、トルクリミッタにおいては一定以上のトルクを発生させる必要上、コイルばね４４の剛性は所要の大きさを持つように製作されるため、端部においては自由状態の形状を維持せんとし、前記のように切断端５５の突き当たりが生じる。このような状態で外環部材４１の内部に組み込んでトルクリミッタとして使用すると、コイルばね４４の切断端５５が内輪４３の外径面に干渉した状態で内輪４３が回転するので、内輪４３の外径面に対する面圧が不均一となり内輪４３の耐久性を損なうことになる。 There are also the following problems. That is, as shown in FIG. 11, when the coil spring 44 having the straight end 45 ′ (46 ′) is attached to the inner ring 43 with a certain tightening allowance, the straight end 45 ′ (46 ′) Winding around the inner ring 43 while being curved with a radius of curvature in the free state, the cut end 55 abuts against the outer diameter surface of the inner ring 43. When the rigidity of the coil spring 44 is low, this is not the case, and the straight end 45 ′ (46 ′) is elastically deformed and closely contacts the outer diameter surface of the inner ring 43. However, the torque limiter generates a torque exceeding a certain level. Therefore, since the rigidity of the coil spring 44 is manufactured so as to have a required size, the free end shape is not maintained at the end portion, and the cutting end 55 is abutted as described above. If the inner ring 43 is rotated in a state where the cut end 55 of the coil spring 44 interferes with the outer diameter surface of the inner ring 43 when incorporated in the outer ring member 41 in this state and used as a torque limiter, the outer ring 43 The surface pressure with respect to the radial surface becomes non-uniform, and the durability of the inner ring 43 is impaired.

この発明は、以上のような観点から、バックラッシの起こり難い構造をもったトルクリミッタを提供するとともに、ストレート端部を有するコイルばねを使用した場合において内輪に対する干渉がなく耐久性に優れたトルクリミッタを提供することを課題とする。 In view of the above, the present invention provides a torque limiter having a structure in which backlash is unlikely to occur, and when using a coil spring having a straight end, the torque limiter has no durability against interference with the inner ring. It is an issue to provide.

前記の課題を解決するために、この発明は、外環部材と、その内部に挿入され一端のボス部において相対回転可能に支持された内輪と、該内輪の外径面に所要の締め代をもって装着されたコイルばねと、前記外環部材の他端部においてその内径面に嵌合固定され内輪外径面との間を閉塞する蓋部材とからなり、前記コイルばねの一端部を前記外環部材に、他端部を前記蓋部材に係合させ、前記内輪と外環部材とが相対回転する際に前記コイルばねに生じる拡径作用により所定のトルクを発生させるようにしたトルクリミッタにおいて、前記コイルばねの拡径方向への一定以上の撓みを規制する規制面を前記外環部材と蓋部材のいずれか一方又は両方に設けた構成を採用したものである。 In order to solve the above-described problems, the present invention includes an outer ring member, an inner ring inserted into the outer ring member and supported in a relatively rotatable manner at a boss portion at one end, and a required tightening margin on an outer diameter surface of the inner ring. A coil member that is mounted, and a lid member that is fitted and fixed to the inner surface of the outer ring member at the other end of the outer ring member and closes the outer ring surface of the inner ring. In the torque limiter, the other end of the member is engaged with the lid member, and when the inner ring and the outer ring member rotate relative to each other, a predetermined torque is generated by a diameter expanding action generated in the coil spring. The structure which provided the control surface which controls the bending more than the fixed to the diameter-expansion direction of the said coil spring in either the said outer ring member and a cover member is employ | adopted.

前記構成のトルクリミッタは、内輪と外環部材の相対回転により、コイルばねが回転されると、コイルばねに拡径作用が発生して一定のトルクを発生させる。トルク発生の初期においてコイルばねの端部において発生せんとする撓みは、規制面に当って規制され、その撓みを発生させる内部応力が迅速にコイルばね全体に拡散され拡径作用が行われ、バックラッシを伴うことなく直ちにトルクが発生する。 When the coil spring is rotated by the relative rotation of the inner ring and the outer ring member, the torque limiter having the above-described configuration generates a constant torque by generating a diameter expansion action on the coil spring. The deflection that occurs at the end of the coil spring at the initial stage of torque generation is regulated against the regulating surface, and the internal stress that causes the deflection is quickly diffused throughout the entire coil spring, and a diameter expansion action is performed. Torque is generated immediately without any trouble.

外環部材に設けられる規制面は、外環部材の内径面に周方向に所要の間隔をおいて設けられた複数の規制突部の内面により形成される構成や、そのような規制突部を設けることなく、外環部材の内径を所定径に設計することにより内径面の全体をもって規制面とした構成を採ることができる。 The restriction surface provided on the outer ring member is configured by an inner surface of a plurality of restriction protrusions provided at a predetermined interval in the circumferential direction on the inner diameter surface of the outer ring member, or such a restriction protrusion. Without providing, it is possible to adopt a configuration in which the entire inner diameter surface is used as a regulating surface by designing the inner diameter of the outer ring member to a predetermined diameter.

また、蓋部材に設けられる規制面は、蓋部材の内面に周方向に所要の間隔をおいて内方に突き出して設けられた複数の規制突部の内面により形成した構成を採ることができる。 Further, the regulating surface provided on the lid member can take a configuration formed by the inner surfaces of a plurality of regulating projections provided inwardly projecting from the inner surface of the lid member at a predetermined interval in the circumferential direction.

さらに、前記コイルばねの両端部がコイル巻き形状を保ったまま切断されたストレート端部である場合において、該コイルばねの自由状態においてその両端部においてそれぞれの端部近傍が他の部分より大きい曲率半径となる逃がし部が形成され、該曲率半径の大きさが該コイルばねを前記内輪に所要の締め代をもって装着した状態においては、他のコイル部分の曲率半径と実質的に等しくなる大きさに設定された構成をとることができる。 Further, in the case where both end portions of the coil spring are straight end portions that are cut while maintaining the coil winding shape, in the free state of the coil spring, the vicinity of each end portion at the both end portions is larger in curvature than the other portions. In a state in which a relief portion having a radius is formed and the radius of curvature is mounted on the inner ring with a required tightening margin, the radius of curvature is substantially equal to the radius of curvature of the other coil portions. A set configuration can be taken.

以上のように、この発明のトルクリミッタは、外環部材や蓋部材に規制面を設けたことにより、トルク発生初期におけるバックラッシによるトルク発生までの遅れを防止することができる。また、コイルばねの端部に逃がし部を設けたことにより、内輪外径面に対するコイルばね端部の干渉が防止され、内輪に作用するばね圧が均等化されることにより内輪の耐久性が向上する。 As described above, the torque limiter according to the present invention can prevent a delay until the torque is generated due to the backlash at the initial stage of torque generation by providing the outer ring member and the lid member with the restricting surfaces. In addition, by providing a relief part at the end of the coil spring, interference of the coil spring end with the outer surface of the inner ring is prevented, and the spring pressure acting on the inner ring is equalized to improve the durability of the inner ring. To do.

以下、添付図面に基づいてこの発明を実施するための最良の形態を説明する。図１及び図２に示した実施形態１のトルクリミッタ１０は、従来の場合と同様に、外環部材１、内輪２、環状の蓋部材３及びコイルばね４とからなる。外環部材１の一端部にボス部５が設けられ、そのボス部５から他端の開放端に至る間にコイルばね４より大径の内径面６が形成される。ボス部５の中心部に軸挿通穴７が設けられ、その軸挿通穴７より内側においてこれより大径の内輪支持部８が設けられる。その内輪支持部８と前記内径面６との段差部を形成するボス部内端面１１の一部に外環部材突部１２（図３（ａ）参照）が設けられる。この外環部材突部１２は前記ボス部内端面１１の径方向の幅全体にわたり、その高さ（軸方向長さ）はコイルばね４を構成する線材の断面の大きさより若干大きく形成されている。また、前記内径面６の開放端に近い部分に周方向の係合溝１３が設けられる。なお、ボス部５側端部の外面にローラ等に対する係合突起１４が設けられる。 The best mode for carrying out the present invention will be described below with reference to the accompanying drawings. The torque limiter 10 according to the first embodiment shown in FIGS. 1 and 2 includes an outer ring member 1, an inner ring 2, an annular lid member 3, and a coil spring 4 as in the conventional case. A boss portion 5 is provided at one end of the outer ring member 1, and an inner diameter surface 6 larger in diameter than the coil spring 4 is formed from the boss portion 5 to the open end of the other end. A shaft insertion hole 7 is provided at the center of the boss portion 5, and an inner ring support portion 8 having a larger diameter is provided inside the shaft insertion hole 7. An outer ring member protrusion 12 (see FIG. 3A) is provided on a part of the boss portion inner end surface 11 that forms a step portion between the inner ring support portion 8 and the inner diameter surface 6. The outer ring member protrusion 12 extends over the entire radial width of the inner end face 11 of the boss, and its height (axial length) is formed slightly larger than the cross-sectional size of the wire constituting the coil spring 4. Further, a circumferential engagement groove 13 is provided in a portion near the open end of the inner diameter surface 6. In addition, the engagement protrusion 14 with respect to a roller etc. is provided in the outer surface of the boss | hub part 5 side edge part.

前記の外環部材１の内径面６において、前記ボス部内端面１１から外環部材１の開放端面側に向けて該内径面６の約半分の範囲にわたり、規制突部２８が周方向に３箇所設けられる。規制突部２８の周方向の間隔は前記の外環部材突部１２を含めて、全周の四分の一程度である。各規制突部２８の内端面２９に先端側が大径となるテーパが付けられている。また、各規制突部２８の内面は半径Ｒの内接円形（図３（ａ）参照）に属する円弧面に形成される。 In the inner diameter surface 6 of the outer ring member 1, there are three restricting projections 28 in the circumferential direction over the range of about half of the inner diameter surface 6 from the boss portion inner end surface 11 toward the open end surface side of the outer ring member 1. Provided. The circumferential interval between the restricting protrusions 28 is about a quarter of the entire circumference including the outer ring member protrusion 12. The inner end face 29 of each restricting protrusion 28 is tapered so that the tip side has a large diameter. Further, the inner surface of each restricting protrusion 28 is formed as an arc surface belonging to an inscribed circle having a radius R (see FIG. 3A).

内輪２は前記軸挿通穴７と同心同一径の内径面を有し、外径面に前記のコイルばね４が所要の締め代で装着される。該内輪２の一端部が前記ボス部５の内輪支持部８において回転自在に嵌合支持され、他端部は外環部材１より外方に突き出す。その突き出した端部の外径面に前記の蓋部材３が嵌合される。内輪２が蓋部材３から突き出した端部に軸（図示省略）に立てたピンとの係合凹所１５が設けられる。 The inner ring 2 has an inner diameter surface that is concentric with the shaft insertion hole 7, and the coil spring 4 is attached to the outer diameter surface with a required tightening allowance. One end portion of the inner ring 2 is rotatably fitted and supported at the inner ring support portion 8 of the boss portion 5, and the other end portion projects outward from the outer ring member 1. The lid member 3 is fitted to the outer diameter surface of the protruding end. An engagement recess 15 with a pin standing on a shaft (not shown) is provided at an end of the inner ring 2 protruding from the lid member 3.

前記の蓋部材３の外径面に係合リブ１６が形成され、その係合リブ１６が前記の係合溝１３に嵌入される。この蓋部材３により外環部材１の内径面と内輪２の外径面との間が閉塞され、内輪２が回転自在に支持される。蓋部材３は外環部材１に対して強固に嵌合されるが、その嵌合強さは蓋部材３の外面に設けた一対の穴１７に所要の工具を差し込で回転させた場合は、外環部材１に対して回転できる程度である。 An engagement rib 16 is formed on the outer diameter surface of the lid member 3, and the engagement rib 16 is fitted into the engagement groove 13. The lid member 3 closes the space between the inner diameter surface of the outer ring member 1 and the outer diameter surface of the inner ring 2, and the inner ring 2 is rotatably supported. The lid member 3 is firmly fitted to the outer ring member 1, but the fitting strength is obtained when a required tool is inserted into a pair of holes 17 provided on the outer surface of the lid member 3 and rotated. The outer ring member 1 can rotate with respect to the outer ring member 1.

また、蓋部材３の内面に蓋部材突部１８（図２、図３（ｂ）参照）が設けられる。この蓋部材突部１８は蓋部材３内面の径方向の幅全体にわたり、その高さはコイルばね４を構成する線材の断面の大きさより若干大きく形成される。また、蓋部材３の内面において、外環部材１の内径面６の軸方向長さの約半分の長さの規制突部３１が周方向に３箇所設けられる。規制突部３１の周方向の間隔は前記の蓋部材突部１８を含めて全周の四分の一程度である。各規制突部３１の内端面３２に先端側が小径となるテーパが付けられている。また、各規制突部３１の内面は前記の規制突部２８と同一半径Ｒの大きさの内接円形に属する円弧面に形成される（図３（ｂ）参照）。 Further, a lid member protrusion 18 (see FIGS. 2 and 3B) is provided on the inner surface of the lid member 3. The lid member protrusion 18 extends over the entire radial width of the inner surface of the lid member 3, and the height thereof is slightly larger than the size of the cross section of the wire constituting the coil spring 4. In addition, on the inner surface of the lid member 3, three restricting protrusions 31 having a length that is about half the axial length of the inner diameter surface 6 of the outer ring member 1 are provided in the circumferential direction. The interval in the circumferential direction of the restricting protrusion 31 is about a quarter of the entire circumference including the lid member protrusion 18. The inner end surface 32 of each restricting protrusion 31 is tapered so that the tip side has a small diameter. The inner surface of each restricting protrusion 31 is formed as an arc surface belonging to an inscribed circle having the same radius R as the restricting protrusion 28 (see FIG. 3B).

コイルばね４は、鋼線（図示の場合は角線であるが、丸線でもよい。）を単一径となるように所要回数巻いたものである。内輪２に装着する前の自由状態において、両端部は基本的にはストレート端部であるが、この場合は端部から約二分の１巻きの範囲において、他のコイル部分より大きい曲率半径をもった逃がし部３３、３４が形成される（図４（ａ）参照）。これらの逃がし部３３、３４以外のコイル部分の内径は、前記内輪２の外径より若干小さく形成されているため、これを内輪２に嵌合させると一定の締め代をもって装着される。 The coil spring 4 is formed by winding a steel wire (a square wire in the case of illustration but a round wire) a required number of times so as to have a single diameter. In the free state before being attached to the inner ring 2, both end portions are basically straight end portions, but in this case, in the range of about one-half turn from the end portion, it has a larger radius of curvature than the other coil portions. Relief portions 33 and 34 are formed (see FIG. 4A). Since the inner diameters of the coil portions other than the escape portions 33 and 34 are formed slightly smaller than the outer diameter of the inner ring 2, when the inner ring 2 is fitted to the inner ring 2, it is mounted with a certain tightening allowance.

コイルばね４を一定の締め代をもって内輪２に装着すると、コイルばね４は若干拡径されその曲率半径が大きくなり、逃がし部３３、３４の曲率半径とほぼ等しくなる（図４（ｂ）参照）。言い替えれば、各逃がし部３３、３４の当初の曲率半径は、内輪２２に装着した状態で他のコイル部分との曲率半径と実質的に等しくなる大きさに設定される。コイルばね４の両端部にこのような逃がし部３３、３４を設けたことにより、それらの端面３３’、３４’と内輪２との干渉が解消される。 When the coil spring 4 is attached to the inner ring 2 with a certain tightening margin, the coil spring 4 is slightly enlarged in diameter and has a larger radius of curvature, which is substantially equal to the radius of curvature of the relief portions 33 and 34 (see FIG. 4B). . In other words, the initial radius of curvature of each relief portion 33, 34 is set to a size that is substantially equal to the radius of curvature with the other coil portions when attached to the inner ring 22. By providing the relief portions 33 and 34 at both ends of the coil spring 4, interference between the end surfaces 33 'and 34' and the inner ring 2 is eliminated.

コイルばね４を前記のように装着した内輪２を外環部材１に組み込み蓋部材３を嵌合する。その後、外環部材１及び内輪２を固定して蓋部材３の穴１７に所要の工具を差し込みコイルばね４の巻き方向に回転させると、その回転途中において蓋部材突部１８がコイルばね４の一方の端面３４’の側面に係合する（図３（ｂ）参照）。さらにコイルばね４の締め付け力に打ち勝つ力を加えて回転させると、他方の端面３４’が外環部材突部１２の側面に係合する（図３（ａ）参照）。これにより、コイルばね４の両端面３３’、３４’がそれぞれ外環部材突部１２と蓋部材突部１８に対し周方向にすき間なく係合される。 The inner ring 2 fitted with the coil spring 4 as described above is assembled into the outer ring member 1 and the lid member 3 is fitted. After that, when the outer ring member 1 and the inner ring 2 are fixed and a required tool is inserted into the hole 17 of the lid member 3 and rotated in the winding direction of the coil spring 4, the lid member protrusion 18 of the coil spring 4 is rotated during the rotation. It engages with the side surface of one end surface 34 ′ (see FIG. 3B). Further, when a force that overcomes the tightening force of the coil spring 4 is applied and rotated, the other end face 34 'engages with the side face of the outer ring member protrusion 12 (see FIG. 3A). Thereby, both end surfaces 33 ′ and 34 ′ of the coil spring 4 are engaged with the outer ring member protrusion 12 and the lid member protrusion 18 without any gaps in the circumferential direction.

このように組み立てた状態において、コイルばね４の外径面の軸方向の全長にわたり、外環部材１の規制突部２８と蓋部材３の規制突部３１の内面が規制面となって一定の規制すき間δ（図３（ｃ）参照）をもって対向する。 In this assembled state, the inner surfaces of the restricting projections 28 of the outer ring member 1 and the restricting projections 31 of the lid member 3 are constant surfaces over the entire length of the outer diameter surface of the coil spring 4 in the axial direction. They are opposed with a regulation gap δ (see FIG. 3C).

前記の規制すき間δは、樹脂部品製造時の公差レンジを考慮し、０．１ｍｍ≦δ≦０．３ｍｍ、好ましくはδ＝０．２ｍｍに設定される。 The restriction gap δ is set to 0.1 mm ≦ δ ≦ 0.3 mm, preferably δ = 0.2 mm in consideration of a tolerance range at the time of manufacturing a resin part.

実施形態１のトルクリミッタは以上のように構成され、従来の場合と同様に、外環部材１と内輪２の相対回転によるコイルばね４の拡径作用に伴い規定トルクが発生するが、トルクの発生初期において従来コイル端部に発生していた撓みは、規制突部２８、３１の内径面が規制面となってコイル端部の膨出が規制されることによりコイル端部における撓みの発生が抑制される。このため、トルクの発生初期においてバックラッシを生じることなくコイルばね４の拡径作用が生じ、直ちにトルクが発生する。また、コイルばね４の両端面３３’、３４’は逃がし部３３、３４が予め形成されているため、内輪２の外径面に干渉することがなく、局部的な圧力の発生が避けられている。 The torque limiter according to the first embodiment is configured as described above. As in the conventional case, a specified torque is generated in accordance with the diameter expansion action of the coil spring 4 due to the relative rotation of the outer ring member 1 and the inner ring 2. The deflection that has occurred at the end of the coil in the early stage of the occurrence is caused by the inner surface of the restricting projections 28 and 31 being restricted and the expansion of the coil end is restricted. It is suppressed. For this reason, the diameter expansion effect | action of the coil spring 4 arises, without producing backlash in the generation | occurrence | production stage of a torque, and a torque generate | occur | produces immediately. Further, since both end surfaces 33 'and 34' of the coil spring 4 are formed with relief portions 33 and 34 in advance, they do not interfere with the outer diameter surface of the inner ring 2 and the generation of local pressure is avoided. Yes.

前記の規制突部２８、３１は、両者によってコイルばね４の全長にわたり規制面を形成するように設けられているが、もし、コイルばね４の端部に対応した部分にのみこれらの規制突部を設けたとすると、その規制突部の後方において前記の撓みが発生することになり撓みの発生を有効に防止することができない。結局全長にわたる規制突部２８、３１を設ける必要がある。なお、規制突部２８、３１は、いずれか一方のみを設け、その軸方向長さをコイルばね４の全長に達するように設定すればよい。 The restriction protrusions 28 and 31 are provided so as to form a restriction surface over the entire length of the coil spring 4, but these restriction protrusions are provided only at a portion corresponding to the end of the coil spring 4. If this is provided, the above-described bending occurs behind the regulating protrusion, and the generation of the bending cannot be effectively prevented. After all, it is necessary to provide the regulation protrusions 28 and 31 over the entire length. Only one of the restricting protrusions 28 and 31 may be provided, and the axial length thereof may be set so as to reach the entire length of the coil spring 4.

また、トルク発生初期におけるコイルばね４の撓みを防止するその他の手段としては、前記の規制突部２８、３１により規制面を形成する手段に変えて、外環部材１の内径面の全体を前記の規制すき間δを持つような径の規制面とすることによっても同様の作用効果を得ることができる。 Further, as other means for preventing the bending of the coil spring 4 at the initial stage of torque generation, the whole inner diameter surface of the outer ring member 1 is changed to the means for forming the restriction surface by the restriction protrusions 28 and 31. A similar effect can be obtained also by using a restricting surface having a diameter having a restricting clearance δ.

また、コイルばね４として従来のように両端部にフックが設けられたものを用いる場合、或いは２段径のコイルばねであっても、トルク発生初期における撓みの発生があるので、前記のような規制突部３３、３４を設けたり、外環部材１の内径面による規制面を設けたりすることは、バックラッシを解消する手段として有効である。
〔試験例１〕
（１）試験内容
図１に示した実施形態１のトルクリミッタにおいて、規制突部２８、３１を設けたものと、これらを設けないものについてバックラッシの大きさの比較試験を行った。
（２）試験条件
発生トルク：３４．５ｍＮ・ｍ（３５０gf・cm）
回転速度：４min^−１
測定雰囲気：室温
回転方向：時計方向回転
（２）試験結果
試験結果を図５に示す。
〔試験例２〕
（１）試験内容：前述の実施形態１のトルクリミッタにおいて、コイルばね４に逃がし部３３、３４を設けたものと、これを設けないものとについて耐久試験を行った。
（２）試験条件
発生トルク：３４．５ｍＮ・ｍ（３５０gf・cm）
回転速度：３００min^−１
回転方向：時計方向回転
耐久時間：１０００時間
試験結果：試験結果を図６に示す。 In addition, when using a coil spring 4 having hooks at both ends as in the prior art, or even a two-stage coil spring, there is a bend at the initial stage of torque generation. Providing the restricting protrusions 33 and 34 or providing a restricting surface by the inner diameter surface of the outer ring member 1 is effective as means for eliminating backlash.
[Test Example 1]
(1) Test content In the torque limiter of the first embodiment shown in FIG. 1, a backlash size comparison test was performed on the one provided with the regulation protrusions 28 and 31 and the one not provided with these.
(2) Test conditions Generated torque: 34.5 mN · m (350 gf · cm)
Rotational speed: 4min ^-1
Measurement atmosphere: room temperature Rotation direction: clockwise rotation (2) Test results The test results are shown in FIG.
[Test Example 2]
(1) Test content: In the torque limiter of the first embodiment, the endurance test was performed on the coil spring 4 provided with the relief portions 33 and 34 and the one not provided with the escape portions 33 and 34.
(2) Test conditions Generated torque: 34.5 mN · m (350 gf · cm)
Rotational speed: 300min ^-1
Rotation direction: clockwise rotation Endurance time: 1000 hours Test result: The test result is shown in FIG.

実施形態の断面図Cross-sectional view of the embodiment 同上の分解斜視図Exploded perspective view （ａ）は図１のＡ−Ａ線の断面図、（ｂ）は同じくＢ−Ｂ線の断面図、（ｃ）は（ｂ）の一部拡大断面図(A) is a sectional view taken along line AA in FIG. 1, (b) is a sectional view taken along line BB, and (c) is a partially enlarged sectional view of (b). （ａ）コイルばねの自然状態の正面図、（ｂ）は前記コイルばねの装着状態における断面図(A) Front view of coil spring in natural state, (b) is a sectional view of the coil spring in a mounted state バックラッシの比較試験結果のグラフBacklash comparison test result graph 耐久性の比較試験結果のグラフGraph of durability test results 従来例のトルクリミッタの断面図Sectional view of a conventional torque limiter 紙さばき部の概略図Schematic diagram of paper separation section 図７のＸ−Ｘ線の断面図Sectional view along line XX in FIG. （ａ）他の従来例の断面図、（ｂ）（ａ）図のコイルばねの断面図(A) Cross-sectional view of another conventional example, (b) Cross-sectional view of coil spring shown in (a) 従来例の問題点の説明のための断面図Sectional drawing for demonstrating the problem of a prior art example

Explanation of symbols

１外環部材
２内輪
３蓋部材
４コイルばね
５ボス部
６内径面
７軸挿通穴
８内輪支持部
１０トルクリミッタ
１１ボス部内端面
１２外環部材突部
１３係合溝
１４係合突起
１５係合凹所
１６係合リブ
１７穴
１８蓋部材突部
２８規制突部
２９内端面
３１規制突部
３２内端面
３３逃がし部
３４逃がし部
３３’ 端面
３４’ 端面 DESCRIPTION OF SYMBOLS 1 Outer ring member 2 Inner ring 3 Cover member 4 Coil spring 5 Boss part 6 Inner diameter surface 7 Shaft insertion hole 8 Inner ring support part 10 Torque limiter 11 Boss part inner end surface 12 Outer ring member protrusion 13 Engagement groove 14 Engagement protrusion 15 Engagement Recess 16 Engaging rib 17 Hole 18 Lid member protrusion 28 Restriction protrusion 29 Inner end face 31 Restriction protrusion 32 Inner end face 33 Relief part 34 Relief part 33 'End face 34' End face

Claims

An outer ring member, an inner ring inserted into the inner ring and supported by a boss portion at one end so as to be relatively rotatable, a coil spring mounted on an outer diameter surface of the inner ring with a required tightening margin, and the outer ring member A cover member that is fitted and fixed to the inner surface of the inner ring at the end and closes the outer surface of the inner ring. One end of the coil spring is engaged with the outer ring member and the other end is engaged with the cover member. And a torque limiter that generates a predetermined torque by a diameter-expanding action that occurs in the coil spring when the inner ring and the outer ring member rotate relative to each other, and both ends of the coil spring maintain a coiled shape. A straight end portion that is cut as it is, and the straight end portion of the coil spring is an outer ring member projection formed on one end portion of the inner diameter surface of the outer ring member, and a lid member formed on the inner surface of the lid member On the side with the protrusion Together are provided with a regulation surface to regulate a certain level of bending of the expanded direction of the coil spring on both of the outer ring member and the lid member, the regulating surface provided on the outer ring member, said outer ring member Formed by inner surfaces of a plurality of restricting projections that are circumferentially spaced on the inner diameter surface, and the restricting surface provided on the lid member is inwardly spaced from the inner surface of the lid member at a required interval in the circumferential direction. A torque limiter formed by inner surfaces of a plurality of restricting protrusions provided so as to protrude from the shaft.

In the free state of the coil spring, a relief portion having a radius of curvature larger than that of the other portion is formed at both ends of the coil spring, and the magnitude of the radius of curvature is a required fastening allowance for the coil spring to the inner ring. 2. The torque limiter according to claim 1, wherein the torque limiter is set to a size that is substantially equal to a radius of curvature of the other coil portion.