JP2008208934A

JP2008208934A - One-way clutch

Info

Publication number: JP2008208934A
Application number: JP2007047044A
Authority: JP
Inventors: Masaaki Honda; 正明本多; Chiyori Sato; ちより佐藤
Original assignee: NTN Corp; NTN Toyo Bearing Co Ltd
Current assignee: NTN Corp
Priority date: 2007-02-27
Filing date: 2007-02-27
Publication date: 2008-09-11

Abstract

<P>PROBLEM TO BE SOLVED: To provide a one-way clutch having lower cost and greater transmissive torque. <P>SOLUTION: In the one-way clutch, pockets 5 are provided in the inner peripheral face 4 of an outer ring 1 formed of sintered metal, cam faces 6 are formed in the pockets 5, rollers 2 are provided in the pockets 5, and a clutch spring 3 is provided for energizing the rollers 2 in the direction of narrowing a space between the cam face 6 of the outer ring 1 and an outer peripheral face 8 of a shaft 7. When torque in one rotating direction is operated between the outer ring 1 and the shaft 7, the rollers 2 are bitten between the cam face 6 of the outer ring 1 and the outer peripheral face 8 of the shaft 7 to transmit torque between the outer ring 1 and the shaft 7. When torque in the other rotating direction is operated, the biting of the rollers 2 is released to cut off the torque transmission between the outer ring 1 and the shaft 7. Metal coating treatment is applied to the cam face 6 of the outer ring 1. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

この発明は、主として事務機の紙送り機構に用いられる一方向クラッチに関する。 The present invention relates to a one-way clutch mainly used for a paper feeding mechanism of an office machine.

プリンタ、複写機などの紙送り機構に用いられる一方向クラッチとして、紙送り機構の軸が挿入される外輪の内周面に、周方向に間隔をおいて複数のポケットを形成し、そのポケット内に、紙送り機構の軸の外周面との間隔を周方向に沿って次第に狭小させるカム面を形成し、前記ポケット内にローラを設け、外輪のカム面と紙送り機構の軸の外周面の間隔が狭小する方向に前記ローラを付勢する弾性部材を設けたものが知られている（特許文献１，２）。 As a one-way clutch used in paper feed mechanisms such as printers and copiers, a plurality of pockets are formed at intervals in the circumferential direction on the inner peripheral surface of the outer ring into which the shaft of the paper feed mechanism is inserted. Forming a cam surface that gradually narrows the interval between the outer periphery of the shaft of the paper feed mechanism along the circumferential direction, and a roller is provided in the pocket, the cam surface of the outer ring and the outer peripheral surface of the shaft of the paper feed mechanism There is known one provided with an elastic member that biases the roller in a direction in which the interval is narrowed (Patent Documents 1 and 2).

この一方向クラッチは、前記外輪と前記軸の間で一方の回転方向のトルクが作用したときは、前記外輪のカム面と前記軸の外周面の間に前記ローラが噛み込んで外輪と軸の間でトルクを伝達する状態（以下、「ロック状態」という）となり、他方の回転方向のトルクが作用したときは、前記ローラが噛み込みを解除してトルク伝達を遮断する状態（以下「空転状態」という）となる。
特許第３２７０６６７号公報特許第３５０１３５２号公報 In this one-way clutch, when a torque in one rotational direction acts between the outer ring and the shaft, the roller is engaged between the outer cam surface of the outer ring and the outer peripheral surface of the shaft. When the torque in the other rotational direction is applied, the roller releases the engagement and shuts off the torque transmission (hereinafter referred to as the “idling state”). ").
Japanese Patent No. 3270667 Japanese Patent No. 3501352

ところで、事務機用の一方向クラッチの外輪は、低コストで大量に生産するため、焼結金属で形成されることが多い。しかし、焼結金属は多孔質なので、焼結金属で外輪を形成すると、カム面に露出したポーラス（空孔）によりカム面の許容面圧が小さくなり、外輪と軸の間で伝達可能なトルクも小さくなる。 By the way, an outer ring of a one-way clutch for an office machine is often made of sintered metal in order to produce a large amount at a low cost. However, since sintered metal is porous, if the outer ring is formed of sintered metal, the allowable surface pressure on the cam surface is reduced by the porous (hole) exposed on the cam surface, and torque that can be transmitted between the outer ring and the shaft Becomes smaller.

そこで、外輪と軸の間で伝達可能なトルクを大きくする方法として、次の方法が考えられる。
１）無垢の金属に切削加工を施して外輪を形成することにより、外輪の強度を向上させ、カム面の許容面圧を大きくする方法
２）外輪と軸の直径を大きくすることにより、ローラとカム面の数を増やし、カム面に作用する面圧を小さくする方法
３）外輪の直径を大きくすることにより、外輪の中心からカム面までの距離を大きくし、カム面に作用する面圧を小さくする方法
４）外輪とローラの軸方向長さを長くすることにより、カム面に作用する面圧を小さくする方法 Therefore, the following method can be considered as a method of increasing the torque that can be transmitted between the outer ring and the shaft.
1) Method to improve the strength of the outer ring by cutting the solid metal to form the outer ring, and to increase the allowable surface pressure of the cam surface 2) By increasing the diameter of the outer ring and the shaft, Method of increasing the number of cam surfaces and reducing the surface pressure acting on the cam surface 3) By increasing the diameter of the outer ring, the distance from the center of the outer ring to the cam surface is increased, and the surface pressure acting on the cam surface is reduced. 4) Method of reducing the surface pressure acting on the cam surface by increasing the axial length of the outer ring and the roller.

しかし、上記１）の方法では、外輪の加工コストが高く、経済的でない。また、２）〜４）の方法では、一方向クラッチが大型化し、事務機に組み込むスペースが大きくなる。 However, in the method 1), the processing cost of the outer ring is high and it is not economical. In the methods 2) to 4), the one-way clutch is increased in size, and the space to be incorporated into the office machine is increased.

この発明が解決しようとする課題は、低コストで、伝達可能なトルクが大きい一方向クラッチを提供することである。 The problem to be solved by the present invention is to provide a one-way clutch that is low in cost and has a large torque that can be transmitted.

上記の課題を解決するため、外輪のカム面に金属皮膜処理を施した。 In order to solve the above problems, a metal film treatment was applied to the cam surface of the outer ring.

この発明の一方向クラッチは、カム面のポーラスを金属皮膜で埋めているので、カム面の許容面圧が高く、外輪と軸の間で伝達可能なトルクが大きい。また、外輪が焼結金属からなるので、外輪を無垢の金属で形成する場合に比べて、低コストである。 In the one-way clutch of the present invention, the porous surface of the cam surface is filled with a metal film, so that the allowable surface pressure of the cam surface is high and the torque that can be transmitted between the outer ring and the shaft is large. In addition, since the outer ring is made of sintered metal, the cost is lower than when the outer ring is made of a solid metal.

図１に、この発明の実施形態の一方向クラッチを示す。この一方向クラッチは、外輪１と、ローラ２と、クラッチばね３とからなる。 FIG. 1 shows a one-way clutch according to an embodiment of the present invention. This one-way clutch includes an outer ring 1, a roller 2, and a clutch spring 3.

外輪１は、鉄を主成分とする焼結金属からなる。外輪１の内周面４には、周方向に一定の間隔をおいて複数のポケット５が形成され、各ポケット５内にはカム面６が形成されている。各カム面６は、外輪１内に軸７を挿入したときに、外輪１のカム面６と軸７の外周面８の間隔が、一方の周方向（図では反時計回り）に沿って次第に狭小するように形成されている。 The outer ring 1 is made of a sintered metal whose main component is iron. A plurality of pockets 5 are formed on the inner peripheral surface 4 of the outer ring 1 at regular intervals in the circumferential direction, and a cam surface 6 is formed in each pocket 5. Each cam surface 6 has an interval between the cam surface 6 of the outer ring 1 and the outer peripheral surface 8 of the shaft 7 along one circumferential direction (counterclockwise in the figure) when the shaft 7 is inserted into the outer ring 1. It is formed to be narrow.

ポケット５には、ローラ２が収容されており、ローラ２は、外輪１のカム面６と軸７の外周面８の間隔が狭小する方向にクラッチばね３で付勢されている。 A roller 2 is accommodated in the pocket 5, and the roller 2 is urged by the clutch spring 3 in a direction in which the distance between the cam surface 6 of the outer ring 1 and the outer peripheral surface 8 of the shaft 7 is reduced.

外輪１は、カム面６を含む表面全体に金属皮膜処理が施されている。金属皮膜処理としては、外輪１を構成する焼結金属よりも硬度の高い金属皮膜を形成する金属皮膜処理を採用することができ、たとえば、硬質クロムめっき（ビッカース硬度１０００程度）、Ｎｉ−Ｐめっき（ビッカース硬度１０００程度）、Ｎｉ−Ｂめっき（ビッカース硬度１０００程度）、Ｎｉ−Ｂ−Ｗめっき（ビッカース硬度８００程度）を採用することができる。 The outer ring 1 is subjected to a metal film treatment on the entire surface including the cam surface 6. As the metal film treatment, a metal film treatment that forms a metal film having a hardness higher than that of the sintered metal constituting the outer ring 1 can be employed. For example, hard chrome plating (Vickers hardness of about 1000), Ni-P plating (Vickers hardness of about 1000), Ni-B plating (Vickers hardness of about 1000), Ni-BW plating (Vickers hardness of about 800) can be employed.

つぎに、この一方向クラッチの動作例を説明する。 Next, an operation example of this one-way clutch will be described.

軸７と外輪１の間にトルクが作用して、軸７が、外輪１のカム面６と軸７の外周面８の間隔が狭小する方向（図では反時計回り）に回転すると、ローラ２がカム面６と外周面８の間に噛み込んでロック状態となり、軸７と外輪１が一体に回転する。 When torque is applied between the shaft 7 and the outer ring 1 and the shaft 7 rotates in a direction (counterclockwise in the figure) in which the distance between the cam surface 6 of the outer ring 1 and the outer peripheral surface 8 of the shaft 7 is reduced, the roller 2 Is engaged between the cam surface 6 and the outer peripheral surface 8 to be locked, and the shaft 7 and the outer ring 1 rotate integrally.

一方、軸７と外輪１の間に反対方向のトルクが作用して、軸７が、外輪１のカム面６と軸７の外周面８の間隔が拡大する方向（図では時計回り）に回転すると、図２に示すように、ローラ２の噛み込みが解除されて空転状態となり、軸７から外輪１へのトルク伝達が遮断される。 On the other hand, torque in the opposite direction acts between the shaft 7 and the outer ring 1, and the shaft 7 rotates in the direction in which the distance between the cam surface 6 of the outer ring 1 and the outer peripheral surface 8 of the shaft 7 increases (clockwise in the figure). Then, as shown in FIG. 2, the biting of the roller 2 is released and the idling state is established, and torque transmission from the shaft 7 to the outer ring 1 is interrupted.

この一方向クラッチは、カム面６のポーラスを金属皮膜で埋めているので、カム面６の許容面圧が高く、外輪１と軸７の間で伝達可能なトルクが大きい。また、外輪１が焼結金属からなるので、外輪１を無垢の金属で形成する場合に比べて、低コストである。 In this one-way clutch, since the porous surface of the cam surface 6 is filled with a metal film, the allowable surface pressure of the cam surface 6 is high, and the torque that can be transmitted between the outer ring 1 and the shaft 7 is large. Further, since the outer ring 1 is made of sintered metal, the cost is lower than when the outer ring 1 is made of a solid metal.

また、この一方向クラッチは、金属皮膜がカム面６のポーラスに浸入してアンカー効果を生じるので、金属皮膜がカム面６から剥がれにくく、長寿命である。 Further, in this one-way clutch, the metal film penetrates into the porous surface of the cam surface 6 to produce an anchor effect, so that the metal film is difficult to peel off from the cam surface 6 and has a long life.

カム面６に施す金属皮膜処理としては、外輪１を構成する焼結金属よりも摩擦係数の高い金属皮膜を形成する金属皮膜処理を採用すると好ましく、たとえば、外輪１が鉄を主成分とする焼結金属からなる場合、カム面６にインジウムめっきを施すと好ましい。このようにすると、カム面６に金属皮膜処理を施さない場合に比べてカム面６の摩擦係数が高くなるので、カム面６の傾斜を大きくすることができ、これにより、外輪１と軸７の間で伝達可能なトルクを大きくすることができる。 As the metal film treatment applied to the cam surface 6, it is preferable to employ a metal film treatment that forms a metal film having a higher coefficient of friction than the sintered metal constituting the outer ring 1. When it consists of a metal, it is preferable to apply indium plating to the cam surface 6. In this way, the coefficient of friction of the cam surface 6 is higher than when the cam surface 6 is not subjected to the metal film treatment, so that the inclination of the cam surface 6 can be increased, whereby the outer ring 1 and the shaft 7 can be increased. The torque that can be transmitted between the two can be increased.

また、カム面６の金属皮膜をめっきで形成する場合、めっきは、電気めっきで行なってもよく、無電解めっきで行なってもよい。 When the metal film on the cam surface 6 is formed by plating, the plating may be performed by electroplating or electroless plating.

また、カム面６の金属皮膜は、他の方式の金属皮膜処理で形成してもよく、たとえば、蒸着や溶射により形成してもよい。 Further, the metal film on the cam surface 6 may be formed by other types of metal film processing, for example, by vapor deposition or thermal spraying.

上記実施形態では、外輪１のカム面６と軸７の外周面８の間に噛み込む係合子としてローラ２を用いた一方向クラッチを例に挙げて説明したが、この発明は、他の形状の係合子を用いた一方向クラッチにも適用してもよく、たとえば、係合子としてボールを用いた一方向クラッチも適用することができる。 In the above embodiment, the one-way clutch using the roller 2 as an engaging member that is engaged between the cam surface 6 of the outer ring 1 and the outer peripheral surface 8 of the shaft 7 has been described as an example. For example, a one-way clutch using a ball as an engaging element can also be applied.

この発明の実施形態の一方向クラッチを軸に装着した状態を示す断面図Sectional drawing which shows the state which mounted | wore the one-way clutch of embodiment of this invention with the axis | shaft 図１のローラが外輪のカム面と軸の外周面の間の噛み合いを解除した状態を示す断面図Sectional drawing which shows the state which the roller of FIG. 1 canceled the meshing | engagement between the cam surface of an outer ring | wheel, and the outer peripheral surface of an axis | shaft.

符号の説明Explanation of symbols

１外輪
３クラッチばね
４内周面
５ポケット
６カム面
７軸
８外周面 1 outer ring 3 clutch spring 4 inner peripheral surface 5 pocket 6 cam surface 7 shaft 8 outer peripheral surface

Claims

焼結金属からなる外輪（１）の内周面（４）に周方向に間隔をおいて複数のポケット（５）を設け、そのポケット（５）内に、前記外輪（１）内に挿入される軸（７）の外周面（８）との間隔を周方向に沿って次第に狭小させるカム面（６）を形成し、そのポケット（５）内に係合子（２）を設け、その係合子（２）を、前記外輪（１）のカム面（６）と前記軸（７）の外周面（８）の間隔が狭小する方向に付勢する弾性部材（３）を設け、前記外輪（１）と前記軸（７）の間で一方の回転方向のトルクが作用したときは、前記外輪（１）のカム面（６）と前記軸（７）の外周面（８）の間に前記係合子（２）が噛み込んで外輪（１）と軸（７）の間でトルクを伝達し、他方の回転方向のトルクが作用したときは、前記係合子（２）が噛み込みを解除して外輪（１）と軸（７）の間でのトルク伝達を遮断する一方向クラッチにおいて、前記外輪（１）のカム面（６）に金属皮膜処理を施したことを特徴とする一方向クラッチ。 A plurality of pockets (5) are provided on the inner peripheral surface (4) of the outer ring (1) made of sintered metal at intervals in the circumferential direction, and the pockets (5) are inserted into the outer ring (1). A cam surface (6) is formed to gradually narrow the distance between the shaft (7) and the outer peripheral surface (8) along the circumferential direction, and an engagement element (2) is provided in the pocket (5). (2) is provided with an elastic member (3) for urging the outer ring (1) in the direction in which the interval between the cam surface (6) of the outer ring (1) and the outer peripheral surface (8) of the shaft (7) is reduced, and the outer ring (1 ) And the shaft (7) when a torque in one rotational direction is applied, the engagement between the cam surface (6) of the outer ring (1) and the outer peripheral surface (8) of the shaft (7). When the coupling (2) is engaged and torque is transmitted between the outer ring (1) and the shaft (7) and the torque in the other rotational direction is applied, the engaging element (2) is engaged. In the one-way clutch that releases torque and interrupts torque transmission between the outer ring (1) and the shaft (7), the cam surface (6) of the outer ring (1) is subjected to a metal film treatment. One way clutch.