JP2004092242A

JP2004092242A - Door closer

Info

Publication number: JP2004092242A
Application number: JP2002256316A
Authority: JP
Inventors: Koichi Nakanishi; 中西　好一; Ryoichi Sasaki; 佐々木　良市; Eiichi Aida; 相田　栄一
Original assignee: Nakanishi Engineering Co Ltd
Current assignee: Nakanishi Engineering Co Ltd
Priority date: 2002-09-02
Filing date: 2002-09-02
Publication date: 2004-03-25
Anticipated expiration: 2022-09-02
Also published as: JP3709561B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a door closer having self-closing and braking functions and requiring no large installation space. <P>SOLUTION: A rotary shaft (11) is attached with a pulley (12) and a drum (19) is provided adjacently to the pulley (12). A spring member (20) is stored in the drum (19). An end of the spring member (20) is fixed to the rotary shaft (11) and the drum (19) in a way that the spring member (20) is pulled in the direction of increasing spring resiliency by the rotation of the rotary shaft (11) when a door is opened. A braking chamber (28) filled with a braking fluid is provided adjacently to the drum (19). The braking chamber (18) is equipped with braking members (41),(45) therein, and the braking member (41) is connected with the rotary shaft (11) by a one-way clutch (40) when the door is closed. This braking member (41) is rotated by receiving rotational resistance, thus closing speed of the door is braked. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
本発明は、開放状態から自動的にドアを閉じることができるようにしたドアクローザに関するものである。
【０００２】
【従来の技術】
ドア枠上部に設置したレール上を走行する吊車にドア本体を支持した引き戸、折り戸、バランスドア等のドアが種々知られているが、これらのドアを自動的に閉じるようにしたドアクローザは、一般にドアを自動的に閉じるための自閉機能装置とドアの閉じ際の衝撃を緩和するため該ドアの閉じ速度を調整する制動機能装置を別々に設置しているものが多い（例えば、特許文献１）。
【０００３】
例えば、従来のドアクローザは、図１（Ａ）に示すように、開口部枠（１）に自閉装置（２）を設け、該自閉装置（２）の連結ワイヤ（３）をドア本体（４）の吊車（５）の支持枠（６）に固定し、ドアを開けるとき、該ワイヤを繰り出し、ぜんまいばね等のばね部材を回転軸の回転により巻き込み、ドア本体を閉じるときは、上記ばね部材に蓄積された復元力により上記連結ワイヤを巻き取り、それにより上記ドア本体（４）を閉じるよう構成されている。また、制動装置（７）は、エアシリンダ等で構成され、ドア本体の閉じ際に、該エアシリンダの当接部にストッパ片（８）が当ってピストンを押し込み、制動するよう開口部枠に固定されている。このように、自閉装置（２）と制動装置（７）の２つの装置をドア本体（４）の上部と開口部枠（１）間に設けるためには、設置スペースの間隔（Ｌ）や高さ（Ｈ）が大きくなり、広いスペースを必要とし、折り戸やバランスドア等のようにドア本体の幅が小さいドアでは設置が困難であり、開口部枠全体の高さが大きくなり、施工性も良くなく、その上、制動装置が閉じ際のみに作動するので、閉じ動作が円滑でなかったり、予期せぬ危険を生じるおそれがあった。
【０００４】
【特許文献１】
特開昭５８−１３１２８１号公報（３頁左下欄、第１図、第７図、
第８図）
【０００５】
【発明が解決しようとする課題】
本発明の解決課題は、上記のように自閉機能と制動機能を有するドアクローザにおいて、設置場所をとらず、開口部枠を小さくでき、施工が簡単で、かつドアを閉じる際に閉じ動作全域にわたって制動できるようにしたドアクローザを提供することである。
【０００６】
【課題を解決するための手段】
本発明によれば、ドアが開く際の回転軸の回転により復元力が蓄積されるよう該回転軸の周囲に巻回したばね部材と、ドアが閉じる際一方向クラッチを介して上記回転軸に連結される制動片を有し該制動片の回転を制動するよう制動流体を充填した制動室を具備し、上記ばね部材及び制動室を上記回転軸の軸方向に並設したことを特徴とするドアクローザが提供され、また好ましくは上記制動室における制動片の回転制動は調整可能に設けられ、上記課題が解決される。
【０００７】
上記のように本発明のドアクローザ（９）は、回転軸の軸方向に沿って自閉機能を効するばね部材と制動機能を有する制動室が奥行方向に重ね合わせて設けられているから、図１（Ｂ）に示すように、ドア本体（４）の上部と開口部枠（１）の間隔（Ｌ１）及び高さ（Ｈ１）が小さく、設置スペースが少なくて済み、またドアクローザ（９）と吊車（５）の間隔も狭くすることができるので、ドア本体の幅が小さい折り戸やバランスドア等にも好適に使用することができる。
【０００８】
【発明の実施の形態】
図２は本発明の一実施例を示し、ドアクローザ本体（１０）は、回転軸（１１）を中央に有し、一端にはプーリー（１２）のボス（１３）が嵌着され、ピン（１４）で固定されており、該プーリー（１２）には連結ワイヤ（１５）が巻き付けられている。該連結ワイヤ（１５）は、係止端末（１６）が該プーリー（１２）に固定され、可動端末（１７）がドアクローザ本体（１０）から引き出され、ドア本体に連結される。該可動端末（１７）の近くにはワッシヤ（１８）を設けてあり、該可動端末（１７）がドアクローザ本体内に引き込まれないようにしてある。なお、ドアクローザをドア本体側に設けた場合は、上記可動端末は開口部枠に連結される。
【０００９】
上記プーリー（１２）に隣接してドラム（１９）が設けられている。該ドラム（１９）には、ぜんまいばね、渦巻ばね等のばね部材（２０）が収納され、該ドラム（１９）の外周にねじ（図示略）等で固定した蓋体（２１）でドラム開口部は覆われている。上記回転軸（１１）は、該蓋体（２１）に形成した軸受孔（２２）及び上記ドラム（１９）のボス（２３）に設けた軸受孔（２４）に回転可能に挿通している。上記ばね部材（２０）は、外方端に設けた外フック（２５）をドラム（１９）の外周に設けた切込み溝（図示略）に挿入係止すると共に内方端に設けた内フック（２６）を上記回転軸（１１）に形成した切込み溝（２７）に挿入係止してあり、ドア本体を開放する際、回転軸（１１）の回転により復元力を蓄積する方向に巻き込まれる。
【００１０】
上記ドラム（１９）に隣接して制動室（２８）が形成されている。該制動室（２８）は、上記ドラム（１９）の外周がねじ（２９）で取り付けられる固定座（３０）と該固定座（３０）の中央に移動可能にねじ着（３１）した調整部材（３２）により形成され、該調整部材（３２）の内面には略円錐状の制動面（３３）が設けられている。該制動室内には供給口（３４）からオイル等の制動流体が所定量充填され、該供給口（３４）には封鎖ねじ（３５）がねじ着（３６）されている。なお、上記制動室（２８）をシールするため、各部材の適所にはＯリング等のシール部材（３７）が設けられている。また、上記調整部材（３２）は、ボス（３８）部分に係止溝（３９）を有し、該係止溝（３９）にドライバー等（図示略）を差し込んで回転することにより回転軸（１１）に沿って上記ドラム（１９）に近づく方向もしくは離れる方向に移動させることができる。なお、上記制動流体の量は調整部材を最大限移動させても支障を生じない量にしてある。
【００１１】
上記制動室（２８）内には、一方向クラッチ（４０）を介して上記回転軸（１１）に連結された制動片（４１）があり、該制動片（４１）には略円錐状の制動面（４２）が設けられている。また、該制動片（４１）のフランジ面（４３）に嵌合する突起（４４）により該制動片（４１）に連結された補助制動片（４５）があり、該補助制動片（４５）は上記ドラム（１９）の摺動面（４６）に摺接している。上記制動片（４１）のフランジ面（４３）は、図２に示すように上記固定座（３０）に形成した内段部（４７）に狭い間隙を存して対向しており、上記補助制動片（４５）は上記ドラム（１９）のボス（２３）に遊嵌している。上記制動片（４１）及び補助制動片（４５）には、制動流体を通過させるよう通孔（４８）が形成され、補助制動片（４５）には制動流体を攪拌するよう複数個の放射壁（４９）が設けられている。
【００１２】
上記一方向クラッチ（４０）は、ドアが閉じるとき上記回転軸（１１）と制動片（４１）を連結し、ドアを開くとき該回転軸（１１）の回転を制動片（４１）に伝えないように機能する公知の適宜の一方向クラッチを使用することができる。この種の一方向クラッチは、一般に、図示を省略した外筒と内筒を有し、内筒を上記回転軸（１１）に固定すると共に外筒を上記制動片（４１）の筒状部（５０）に固定してある。なお、該外筒は上記調整部材（３２）のボス（３８）部に形成した受孔（５１）に遊嵌しており、該調整部材（３２）に回転軸（１１）の回転が伝達されることはない。
【００１３】
上述したように上記調整部材（３２）は回転軸（１１）に沿って移動可能に設けられているから、該調整部材（３２）を移動させることにより該調整部材（３２）の制動面（３３）と制動片（４１）の制動面（４２）間の間隔を変更することができ、それにより該制動片を制動する制動力を調整することができる。なお、図３に示すように、調整部材（３２）のフランジ面（５２）が固定座（３０）の段部（５３）に当る位置まで調整部材（３２）を最大に移動させても、上記制動面間には微少間隙が存するように寸法を定めてある。
【００１４】
上記固定座（３０）には、ねじ（５４）によりケース（５５）を固定してあり、該ケース（５５）に間隔棒（５６）及びねじ（５７）を介してプーリー側ケース（５８）を固定してある。このとき、上記プーリー（１２）がプーリー側ケース（５８）内で支障なく回転できるよう該ケース（５８）の内面とプーリー（１２）の外面間に隙間（Ｓ）が形成されるようにしてある。なお、上記ケース（５８）には、ドアクローザ本体を開口部枠等に取り付けるための取付脚（５９）が設けられている。
【００１５】
上記ドアクローザ（９）を図１（Ｂ）に示すように、開口部枠（１）に固定し、連結ワイヤ（１５）の可動端末（１７）を吊車（５）の支持枠（６）に固定してドアを開くと、該連結ワイヤ（１５）が引き出されることにより上記プーリー（１２）が回転し、該プーリーが固定されている回転軸（１１）も回転する。この回転軸の回転により上記ばね部材（２０）が巻き込まれ、復元力が増加（蓄積）される。この際、上記一方向クラッチ（４０）は、回転軸（１１）の回転を制動片（４１）に伝達しないので、制動力を生じることはなく、ドアの開き力はばね部材（２０）の力のみとなるから、ドアの開きは容易である。
【００１６】
ドアを閉じる際は、ドアから手を放すと、上記ばね部材（２０）の復元力により回転軸（１１）はドア開放時とは反対方向に回転する。これにより、プーリー（１２）も回転し、連結ワイヤ（１５）を巻き込み、吊車（５）を引き寄せ、ドアは閉じ方向に移動させられる。このとき、上記一方向クラッチ（４０）は、回転軸（１１）と制動片（４１）を連結するから、該制動片（４１）と補助制動片（４５）は制動室（２８）内で回転するが、上記補助制動片（４５）は制動流体を介してドラム（１９）の摺動面（４６）に接しており、制動片（４１）のフランジ面（４３）や制動面（４２）と対向する制動室（２８）の内面との隙間は微小であり、また放射壁（４９）が制動流体中に突出しているので各々の場所で回転抵抗が生じ、ドアの閉じ速度は制動される。
【００１７】
上記ドアの閉じ速度は、上記制動片（４１），（４５）の回転抵抗の大小により変化するから、上記調整部材（３２）を回転させて制動片と制動室の内面との隙間を変えれば、上記閉じ速度を調整することができる。
【００１８】
【発明の効果】
本発明は上記のように構成され、回転軸の奥行方向に自閉機能を有するばね部材と制動機能を有する制動室を重ね合わせて設けたので、１つのドアクローザで自閉装置と制動装置の機能を有し、設置場所が少なくて済み、吊車の近くに設けることができるからドア幅が小さなドアにも対応することができ、開口部枠の高さが小さくて済み、施工も簡単で経済的であり、その上、閉じ動作において、どの位置からでも制動作用が利くので、安全であり、動作が円滑である。
【図面の簡単な説明】
【図１】ドアの納まり状態を示し、（Ａ）は従来のドアの説明図、（Ｂ）は本発明のドアの説明図。
【図２】本発明の一実施例を示す半断面図。
【図３】制動力を最大に調整したときの一部の断面図。
【図４】本発明のドアクローザの正面図。
【符号の説明】
１０…ドアクローザ本体
１１…回転軸
１２…プーリー
１５…連結ワイヤ
１９…ドラム
２０…ばね部材
２１…蓋体
２８…制動室
３０…固定座
３２…調整部材
３５…封鎖ねじ
４０…一方向クラッチ
４１…制動片
４５…補助制動片
５５…ケース
５８…プーリー側ケース
５９…取付脚[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a door closer capable of automatically closing a door from an open state.
[0002]
[Prior art]
Various types of doors such as sliding doors, folding doors, and balanced doors that support the door body on a hanging vehicle that runs on a rail installed above the door frame are known, but a door closer that automatically closes these doors is known as a door closer. Generally, a self-closing function device for automatically closing a door and a braking function device for adjusting a closing speed of the door in order to reduce an impact when the door is closed are often installed separately (for example, see Patent Document 1). 1).
[0003]
For example, in a conventional door closer, as shown in FIG. 1A, a self-closing device (2) is provided in an opening frame (1), and a connecting wire (3) of the self-closing device (2) is connected to a door body ( When the door is opened, the wire is paid out when the door is opened, the spring member such as a mainspring is wound in by the rotation of the rotation shaft, and when the door body is closed, the above-described spring is used. The connecting wire is wound up by the restoring force accumulated in the member, thereby closing the door body (4). The braking device (7) is composed of an air cylinder or the like. When the door body is closed, the stopper piece (8) comes into contact with the abutting portion of the air cylinder to push the piston and to apply braking to the opening frame. Fixed. Thus, in order to provide the two devices, the self-closing device (2) and the braking device (7), between the upper part of the door body (4) and the opening frame (1), the space (L) of the installation space, The height (H) increases, requiring a large space, and it is difficult to install a door with a small width such as a folding door or a balance door. In addition, since the braking device operates only when the brake device is closed, the closing operation may not be smooth or may cause an unexpected danger.
[0004]
[Patent Document 1]
JP-A-58-131281 (page 3, lower left column, FIG. 1, FIG. 7,
(Fig. 8)
[0005]
[Problems to be solved by the invention]
The problem to be solved by the present invention is to provide a door closer having a self-closing function and a braking function as described above, which does not take up installation space, can reduce the size of an opening frame, is easy to construct, and covers the entire closing operation when closing the door. An object of the present invention is to provide a door closer that can be braked.
[0006]
[Means for Solving the Problems]
According to the present invention, the spring member wound around the rotating shaft so that a restoring force is accumulated by the rotation of the rotating shaft when the door opens, and the rotating shaft via the one-way clutch when the door closes. A braking chamber filled with a braking fluid so as to brake the rotation of the braking piece, wherein the spring member and the braking chamber are juxtaposed in the axial direction of the rotating shaft. A door closer is provided, and preferably the rotational braking of the braking piece in the braking chamber is adjustable so as to solve the above problem.
[0007]
As described above, the door closer (9) of the present invention is provided with a spring member that has a self-closing function and a braking chamber having a braking function that are provided in the depth direction so as to overlap each other along the axial direction of the rotation shaft. As shown in FIG. 1 (B), the space (L1) and height (H1) between the upper part of the door body (4) and the opening frame (1) are small, the installation space is small, and the door closer (9) is not required. Since the distance between the hanging wheels (5) can be narrowed, it can be suitably used for a folding door or a balance door having a small door body.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 2 shows an embodiment of the present invention, in which a door closer body (10) has a rotating shaft (11) at the center, a boss (13) of a pulley (12) is fitted at one end, and a pin (14). ), And a connecting wire (15) is wound around the pulley (12). The connecting wire (15) has a locking terminal (16) fixed to the pulley (12), a movable terminal (17) pulled out from the door closer body (10), and connected to the door body. A washer (18) is provided near the movable terminal (17) to prevent the movable terminal (17) from being pulled into the door closer body. When the door closer is provided on the door body side, the movable terminal is connected to the opening frame.
[0009]
A drum (19) is provided adjacent to the pulley (12). A spring member (20) such as a mainspring spring or a spiral spring is housed in the drum (19), and the drum opening is formed by a lid (21) fixed to the outer periphery of the drum (19) with screws (not shown) or the like. Is covered. The rotating shaft (11) is rotatably inserted into a bearing hole (22) formed in the lid (21) and a bearing hole (24) provided in a boss (23) of the drum (19). The spring member (20) inserts and locks an outer hook (25) provided on an outer end into a cut groove (not shown) provided on the outer periphery of the drum (19), and an inner hook (25) provided on an inner end. 26) is inserted and locked in a notch groove (27) formed in the rotating shaft (11), and when the door body is opened, it is wound in a direction in which a restoring force is accumulated by rotation of the rotating shaft (11).
[0010]
A braking chamber (28) is formed adjacent to the drum (19). The brake chamber (28) includes a fixed seat (30) to which the outer periphery of the drum (19) is attached with a screw (29) and an adjusting member (31) movably screwed (31) to the center of the fixed seat (30). 32), and a substantially conical braking surface (33) is provided on the inner surface of the adjusting member (32). The braking chamber is filled with a predetermined amount of a braking fluid such as oil from a supply port (34), and a closing screw (35) is screwed (36) into the supply port (34). In order to seal the braking chamber (28), a sealing member (37) such as an O-ring is provided at an appropriate position of each member. The adjusting member (32) has a locking groove (39) in the boss (38) portion, and inserts a driver or the like (not shown) into the locking groove (39) to rotate the rotation shaft ( 11) can be moved in a direction approaching or away from the drum (19). The amount of the braking fluid is set so as not to cause a problem even when the adjusting member is moved to the maximum.
[0011]
In the braking chamber (28), there is a braking piece (41) connected to the rotating shaft (11) via a one-way clutch (40), and the braking piece (41) has a substantially conical braking. A surface (42) is provided. There is also an auxiliary brake piece (45) connected to the brake piece (41) by a projection (44) fitted on the flange surface (43) of the brake piece (41), and the auxiliary brake piece (45) is It is in sliding contact with the sliding surface (46) of the drum (19). As shown in FIG. 2, the flange surface (43) of the braking piece (41) faces the inner step (47) formed on the fixed seat (30) with a small gap therebetween, and The piece (45) is loosely fitted to the boss (23) of the drum (19). The brake piece (41) and the auxiliary brake piece (45) are formed with through holes (48) for allowing the brake fluid to pass therethrough, and the auxiliary brake piece (45) is provided with a plurality of radial walls for stirring the brake fluid. (49) is provided.
[0012]
The one-way clutch (40) connects the rotating shaft (11) and the braking piece (41) when the door is closed, and does not transmit the rotation of the rotating shaft (11) to the braking piece (41) when the door is opened. Any suitable one-way clutch known in the art that functions as such can be used. This type of one-way clutch generally has an outer cylinder and an inner cylinder, not shown, and fixes the inner cylinder to the rotation shaft (11) and connects the outer cylinder to the cylindrical portion (41) of the braking piece (41). 50). The outer cylinder is loosely fitted in a receiving hole (51) formed in the boss (38) of the adjusting member (32), and the rotation of the rotating shaft (11) is transmitted to the adjusting member (32). Never.
[0013]
As described above, since the adjusting member (32) is provided so as to be movable along the rotation axis (11), the braking surface (33) of the adjusting member (32) is moved by moving the adjusting member (32). ) And the distance between the braking surface (42) of the braking piece (41) can be changed, whereby the braking force for braking the braking piece can be adjusted. As shown in FIG. 3, even if the adjustment member (32) is moved to the maximum position until the flange surface (52) of the adjustment member (32) hits the step (53) of the fixed seat (30), The dimensions are determined so that there is a minute gap between the braking surfaces.
[0014]
A case (55) is fixed to the fixed seat (30) with a screw (54), and a pulley side case (58) is attached to the case (55) via a spacing rod (56) and a screw (57). It is fixed. At this time, a gap (S) is formed between the inner surface of the case (58) and the outer surface of the pulley (12) so that the pulley (12) can rotate without trouble in the pulley-side case (58). . The case (58) is provided with mounting legs (59) for mounting the door closer body to the opening frame or the like.
[0015]
As shown in FIG. 1B, the door closer (9) is fixed to the opening frame (1), and the movable terminal (17) of the connecting wire (15) is fixed to the support frame (6) of the hoisting vehicle (5). Then, when the door is opened, the pulley (12) rotates by pulling out the connecting wire (15), and the rotating shaft (11) to which the pulley is fixed also rotates. The rotation of the rotating shaft entrains the spring member (20), and the restoring force increases (accumulates). At this time, since the one-way clutch (40) does not transmit the rotation of the rotating shaft (11) to the braking piece (41), no braking force is generated, and the opening force of the door is the force of the spring member (20). The door is easy to open because it is only the case.
[0016]
When the door is closed, when the user releases his hand from the door, the rotating shaft (11) rotates in the direction opposite to the direction when the door is opened due to the restoring force of the spring member (20). As a result, the pulley (12) also rotates, entrains the connecting wire (15), pulls the puller (5), and moves the door in the closing direction. At this time, since the one-way clutch (40) connects the rotating shaft (11) and the brake piece (41), the brake piece (41) and the auxiliary brake piece (45) rotate in the brake chamber (28). However, the auxiliary braking piece (45) is in contact with the sliding surface (46) of the drum (19) via the braking fluid, and is in contact with the flange surface (43) and the braking surface (42) of the braking piece (41). The clearance between the opposing inner surface of the braking chamber (28) is minute, and the radial wall (49) protrudes into the braking fluid, so that rotational resistance is generated at each location, and the closing speed of the door is braked.
[0017]
Since the closing speed of the door changes depending on the magnitude of the rotational resistance of the braking pieces (41) and (45), if the adjusting member (32) is rotated to change the gap between the braking piece and the inner surface of the braking chamber. The closing speed can be adjusted.
[0018]
【The invention's effect】
Since the present invention is configured as described above, and the spring member having the self-closing function and the braking chamber having the braking function are provided in an overlapping manner in the depth direction of the rotating shaft, the functions of the self-closing device and the braking device can be performed by one door closer. It has a small installation space, and can be installed near a hanging car, so it can be used for doors with small door widths, and the opening frame height is small, and construction is easy and economical. In addition, in the closing operation, since the braking action is effective from any position, the operation is safe and the operation is smooth.
[Brief description of the drawings]
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a state in which a door is accommodated, (A) is an explanatory view of a conventional door, and (B) is an explanatory view of a door of the present invention.
FIG. 2 is a half sectional view showing one embodiment of the present invention.
FIG. 3 is a partial cross-sectional view when a braking force is adjusted to a maximum.
FIG. 4 is a front view of the door closer of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Door closer main body 11 ... Rotary shaft 12 ... Pulley 15 ... Connection wire 19 ... Drum 20 ... Spring member 21 ... Lid 28 ... Braking chamber 30 ... Fixed seat 32 ... Adjustment member 35 ... Sealing screw 40 ... One-way clutch 41 ... Braking Piece 45 ... Auxiliary braking piece 55 ... Case 58 ... Pulley side case 59 ... Mounting leg

Claims

A spring member wound around the rotating shaft so that a restoring force is accumulated by rotation of the rotating shaft when the door is opened, and a braking piece connected to the rotating shaft via a one-way clutch when the door is closed. A door closer, comprising: a brake chamber filled with a brake fluid so as to brake the rotation of the brake piece, wherein the spring member and the brake chamber are juxtaposed in an axial direction of a rotation shaft.

The door closer according to claim 1, further comprising a pulley for winding a connection wire connecting the door and the opening frame adjacent to the spring member.

3. The door closer according to claim 1, wherein the brake chamber is provided with an inner surface facing the brake piece so as to be able to approach and separate so as to adjust rotation braking of the brake piece. 4.

When the door is opened when the connecting wire wound around the pulley is pulled out when the door is opened, the pulley is fixed to the rotating shaft so that the rotating shaft rotates, and a drum containing a spring member is provided adjacent to the pulley to open the door. One end of the spring member is fixed to the rotation shaft and the other end is fixed to the drum so that a restoring force is accumulated by rotation of the rotation shaft, and a braking chamber filled with a braking fluid is provided adjacent to the drum. A door closer in which the braking piece is inserted into the braking chamber and the braking piece is connected to the rotating shaft via a one-way clutch that transmits rotation of the rotating shaft when the door is closed.

5. The door closer according to claim 4, wherein the braking chamber includes a fixed seat and an adjusting member movably screwed to the fixed seat.