JPH10246312A

JPH10246312A - Gear

Info

Publication number: JPH10246312A
Application number: JP4832497A
Authority: JP
Inventors: Shinichi Oba; 真一大場
Original assignee: Fuji Xerox Co Ltd
Current assignee: Fujifilm Business Innovation Corp
Priority date: 1997-03-03
Filing date: 1997-03-03
Publication date: 1998-09-14

Abstract

PROBLEM TO BE SOLVED: To provide a gear formed in a mold, in which rigidity is compatible with accuracy. SOLUTION: A gear 10 is formed in a mold, and material between a bearing boss 14 and a tooth part 12 is removed. A rib 16 is radially extended from the bearing boss 14 to support the tooth part 12 of a tooth bottom 12A. Since the rib 16 is arranged outside a region where the tooth part engages with a small gear 28 or a rotary gear, no chatter is generated in the region of engagement of the tooth part 12, and thus the gear 10 can be formed by molding with high accuracy. Further, since the rib 16 supports the outside of engagement of the tooth part 12, required rigidity can be obtained. Thus, when the gear in which the accuracy is compatible with rigidity, is used in a gear train of an image forming device, no rotational irregularities are generated, and thus the generation of hunting can be prevented.

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、駆動力を伝達する
歯車列を構成する歯車に関し、特に、画像形成装置の駆
動力伝達系に用いられる歯車に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gear constituting a gear train for transmitting a driving force, and more particularly to a gear used for a driving force transmission system of an image forming apparatus.

【０００２】[0002]

【従来の技術】画像形成装置の駆動機構には、図５〜図
７に示すように、低コストや騒音が少ない点からモール
ドで成形した歯車３６が使用されているが、歯車３６の
機能としては、歯部３８の歯底３８Ａの肉厚が一定であ
り、且つ所定の剛度を備えていることが必要である。2. Description of the Related Art As a driving mechanism of an image forming apparatus, as shown in FIGS. 5 to 7, a gear 36 formed by molding is used because of its low cost and low noise. It is necessary that the tooth bottom 38A of the tooth portion 38 has a constant thickness and a predetermined rigidity.

【０００３】このため、軸受けボス４０と歯底３８Ａの
裏面とをつなぐ円形のリブ４２を設け、歯底３８Ａを裏
側から補強し、さらに、この円形のリブ４２を軸受けボ
ス４０から放射状に延びる三角形の補助リブ４４で補強
している。For this reason, a circular rib 42 is provided to connect the bearing boss 40 and the back surface of the tooth bottom 38A to reinforce the tooth bottom 38A from the back side. The auxiliary ribs 44 are reinforced.

【０００４】このように、補助リブ４４を歯底３８Ａに
直接接触させない構造では、歯底３８Ａの周方向に沿っ
た肉厚が一定となり、成形時のヒケが少なく、歯部３８
の成形精度は向上するが、負荷が歯部３８に加わったと
き、歯底３８Ａがリブ４２を中心として両側へ折れ曲が
るように撓むことがある。このように、噛み合い部分が
変形すると、回転ムラが発生し、バンディングと呼ばれ
る画像劣化が生じる。一方、図８〜図１０に示す歯車４
６のように、歯部４８の歯底４８Ａの剛性を上げるため
に、矩形状の補助リブ５０で軸受けボス４０と歯底４８
Ａの裏面とをつなぐ方法も考えられる。しかし、この構
造では、歯部４８の剛性は向上するが、歯底４８Ａの周
方向に沿って等間隔で厚肉となり成形時にヒケが発生
し、歯部４８に窪みが生じ成形精度が落ちるため、回転
ムラが発生してバンディングを起こす。As described above, in the structure in which the auxiliary ribs 44 are not in direct contact with the tooth bottom 38A, the thickness of the tooth bottom 38A along the circumferential direction is constant, the sink during molding is small, and the tooth portion 38 is not formed.
However, when a load is applied to the tooth portion 38, the tooth bottom 38A may bend so as to bend to both sides around the rib 42. As described above, when the meshing portion is deformed, rotation unevenness occurs, and image deterioration called banding occurs. On the other hand, the gear 4 shown in FIGS.
As shown in FIG. 6, in order to increase the rigidity of the tooth bottom 48A of the tooth portion 48, the bearing boss 40 and the tooth bottom 48 are
A method of connecting the back surface of A is also conceivable. However, in this structure, although the rigidity of the tooth portion 48 is improved, the tooth portion 48 becomes thick at equal intervals along the circumferential direction of the tooth bottom 48A, and sinks occur at the time of molding. , Rotation unevenness occurs and banding occurs.

【０００５】このように、モールドで成形される従来の
肉抜き構造の歯車では、剛性と精度を両立させることが
困難であった。[0005] As described above, it is difficult to achieve both rigidity and accuracy in a conventional gear having a lightened structure formed by molding.

【０００６】[0006]

【発明が解決しようとする課題】本発明は上記事実を考
慮して、モールドで成形される歯車であっても、剛性と
精度を同時に向上させることを課題とする。SUMMARY OF THE INVENTION In view of the above fact, it is an object of the present invention to simultaneously improve the rigidity and accuracy of a gear formed by molding.

【０００７】[0007]

【課題を解決するための手段】請求項１に記載の発明で
は、歯車がモールドで成形され、軸受け部と歯部との間
が肉抜きされている。軸受け部からは、半径方向へリブ
が延びており、歯部の歯底を支持している。このリブ
は、歯部の噛み合い領域の外側に配置されているので、
歯部の噛み合い領域にヒケを生じさせず、モールドで精
度よく歯車を成形することができる。また、リブが歯部
の噛み合い領域の外側を支持しているので、必要な剛度
が得られる。According to the first aspect of the present invention, the gear is formed by molding, and the gap between the bearing portion and the tooth portion is lightened. A rib extends in the radial direction from the bearing portion, and supports the root of the tooth portion. Since this rib is located outside the meshing region of the teeth,
The gear can be accurately formed by a mold without causing sink marks in the meshing region of the tooth portion. Further, since the rib supports the outside of the meshing region of the teeth, the required rigidity can be obtained.

【０００８】このように、精度と剛性が両立した歯車
を、画像形成装置の歯車列に使用することで、回転ムラ
がなく、バンディングの発生を防止することができる。As described above, by using a gear having both accuracy and rigidity in the gear train of the image forming apparatus, it is possible to prevent rotation unevenness and prevent banding.

【０００９】請求項２に記載の発明では、軸受け部から
は、半径方向へ延びるリブが、歯底の歯幅方向の両側に
それぞれ位置し、歯底の歯幅方向の端部を周方向に沿っ
て支持している。According to the second aspect of the present invention, ribs extending in the radial direction are respectively located on both sides of the root in the width direction of the tooth bottom from the bearing portion, and the ends of the tooth bottom in the width direction of the tooth root are arranged circumferentially. Along.

【００１０】また、リブは、軸受け部の端部から型抜き
可能なように互いにラップしないように配置されてお
り、且つ補助リブが、リブと軸受け部とをつないで、リ
ブの倒れを防いでいる。The ribs are arranged so as not to overlap each other so as to be able to be die-cut from the end of the bearing portion, and the auxiliary rib connects the rib and the bearing portion to prevent the rib from falling down. I have.

【００１１】このように、歯底の歯幅方向の両端部をリ
ブで支持することにより、歯部の剛性が向上する。ま
た、リブは歯底を周方向に沿って支持しているので、成
形時のヒケが少なく、歯部の噛み合い領域の肉厚が均一
となる。さらに、軸受け部の両側に配置されたリブは、
軸方向から見たときラップしていないので、軸受け部の
軸方向から型抜き可能となっている。As described above, the rigidity of the tooth portion is improved by supporting both ends of the tooth bottom in the tooth width direction with the ribs. In addition, since the rib supports the tooth bottom along the circumferential direction, the sink at the time of molding is small, and the thickness of the meshing region of the tooth portion is uniform. Furthermore, the ribs arranged on both sides of the bearing part
Since it is not wrapped when viewed from the axial direction, the die can be removed from the axial direction of the bearing portion.

【００１２】[0012]

【発明の実施の形態】図１〜図３に示すように、本形態
に係る歯車１０は、歯部１２と軸受けボス１４との間が
肉抜きされた構造であり、モールドによって成形され
る。歯部１２は、円筒状の歯底１２Ａと、この歯底１２
Ａから突設され歯溝１２Ｂを形成する歯１２Ｃとから構
成されている。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 to 3, a gear 10 according to the present embodiment has a structure in which a portion between a tooth portion 12 and a bearing boss 14 is lightened, and is formed by molding. The tooth portion 12 includes a cylindrical bottom 12A and the bottom 12A.
A protruding from A and forming a tooth groove 12B.

【００１３】歯底１２Ａの歯幅方向の端部には、両側に
それぞれ、軸受けボス１４から半径方向へ延びて歯底１
２Ａを周方向に沿って支持する扇型状のリブ１６が配置
されている。このリブ１６は、軸受けボス１４の軸方向
へ型抜き可能なように、軸方向から見たとき、互いにラ
ップしないように配置されている。At the ends in the tooth width direction of the tooth bottom 12A, the tooth bottom 1A extends radially from the bearing boss 14 on each side.
A fan-shaped rib 16 that supports 2A along the circumferential direction is arranged. The ribs 16 are arranged so as not to overlap each other when viewed from the axial direction so that the ribs 16 can be die-cut in the axial direction of the bearing boss 14.

【００１４】また、図３に示すように、リブ１６は、歯
１２Ｃの噛み合い領域から外側に配置されており、すな
わち、リブ１６は実際に駆動力を伝達する歯１２Ｃの外
側にある。従って、歯１２Ｃの噛み合い領域にヒケを発
生させず、歯部１２の肉厚を均一にすることができる。
さらに、リブ１６は、軸受けボス１４の軸方向に沿って
形成された三角状の補助リブ１８によって、倒れないよ
うに補強されている。Further, as shown in FIG. 3, the ribs 16 are arranged outside the meshing region of the teeth 12C, that is, the ribs 16 are outside the teeth 12C which actually transmit the driving force. Therefore, sinks are not generated in the meshing region of the teeth 12C, and the thickness of the teeth 12 can be made uniform.
Further, the rib 16 is reinforced by a triangular auxiliary rib 18 formed along the axial direction of the bearing boss 14 so as not to fall down.

【００１５】次に、本形態に係る歯車で構成された画像
形成装置の感光体を回転させる駆動機構を説明する。Next, a description will be given of a drive mechanism for rotating the photosensitive member of the image forming apparatus constituted by the gears according to the present embodiment.

【００１６】図３及び図４に示すように、減速歯車２０
が駆動モータ２２の駆動歯車２４と噛み合い、減速歯車
２６の小歯車２８を介して歯車１０に駆動力を伝達す
る。ここで、小歯車２８の歯幅より、歯車１０のリブ１
６の内壁間隔は大きく、換言すれば、リブ１６は、歯１
２Ｃと歯２８Ｃの噛み合い領域から外側に位置してい
る。また、感光体３０を回転させる回転歯車３２の歯幅
より、歯車１０のリブ１６の内壁間隔は大きくなってい
る。As shown in FIG. 3 and FIG.
Meshes with the drive gear 24 of the drive motor 22 and transmits the drive force to the gear 10 via the small gear 28 of the reduction gear 26. Here, the rib 1 of the gear 10 is determined based on the tooth width of the small gear 28.
6 has a large inner wall interval, in other words, the ribs 16
It is located outside the meshing region of 2C and tooth 28C. Further, the interval between the inner walls of the rib 16 of the gear 10 is larger than the tooth width of the rotary gear 32 for rotating the photoconductor 30.

【００１７】これによって、小歯車２８、回転歯車３２
が、精度の良い歯底１２Ａの肉厚の均一な部分で噛み合
うので、回転ムラが生じない。この結果、バンディング
を解消することができる。また、同時に、歯底１２Ａの
幅方向の両端部を支えるリブ１６によって歯部１２の剛
性が保たれる。Thus, the small gear 28 and the rotary gear 32
However, since the tooth bottom 12A meshes with a highly accurate portion having a uniform thickness, rotation unevenness does not occur. As a result, banding can be eliminated. At the same time, the rigidity of the tooth portion 12 is maintained by the ribs 16 supporting both end portions in the width direction of the tooth bottom 12A.

【００１８】[0018]

【発明の効果】本発明は上記構成としたので、モールド
によって、剛性と精度を備えた歯車を成形することがで
きる。According to the present invention having the above-described structure, a gear having rigidity and precision can be formed by molding.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本形態に係る歯車を一部切欠いた斜視図であ
る。FIG. 1 is a perspective view in which a gear according to the present embodiment is partially cut away.

【図２】本形態に係る歯車の平面図である。FIG. 2 is a plan view of the gear according to the embodiment.

【図３】本形態に係る歯車で歯車列が構成された画像形
成装置の駆動系の一部断面図である。FIG. 3 is a partial cross-sectional view of a drive system of an image forming apparatus in which a gear train is configured by gears according to the embodiment.

【図４】本形態に係る歯車で歯車列が構成された画像形
成装置の駆動系の斜視図である。FIG. 4 is a perspective view of a drive system of an image forming apparatus in which a gear train is configured by gears according to the embodiment.

【図５】従来の歯車を一部切欠いた斜視図である。FIG. 5 is a perspective view of a conventional gear partially cut away.

【図６】従来の歯車の平面図である。FIG. 6 is a plan view of a conventional gear.

【図７】図６の７−７線断面図である。FIG. 7 is a sectional view taken along line 7-7 of FIG. 6;

【図８】従来の歯車を一部切欠いた斜視図である。FIG. 8 is a perspective view of a conventional gear partially cut away.

【図９】従来の歯車の平面図である。FIG. 9 is a plan view of a conventional gear.

【図１０】図９の１０−１０線断面図である。FIG. 10 is a sectional view taken along line 10-10 of FIG. 9;

【符号の説明】[Explanation of symbols]

１０歯車１６リブ１８補助リブ 10 gear 16 rib 18 auxiliary rib

Claims

【特許請求の範囲】[Claims]

【請求項１】モールドで成形され、軸受け部と歯部と
の間が肉抜きされた歯車において、前記軸受け部から半径方向へ延び前記歯部の歯底を支持
するリブが、歯部の噛み合い領域の外側に配置されてい
ることを特徴とする歯車。1. A gear formed by molding and having a hollow between a bearing portion and a tooth portion, wherein a rib extending in a radial direction from the bearing portion and supporting a tooth bottom of the tooth portion engages with the tooth portion. A gear, which is arranged outside the region.

【請求項２】前記リブが前記歯底の歯幅方向の両側に
それぞれ位置し、歯底の歯幅方向の端部を周方向に沿っ
て支持すると共に、軸受け部の両端側から型抜き可能な
ように互いにラップしないように配置され、このリブと
軸受け部とをつなぐ補助リブが軸受け部の軸方向に沿っ
て形成されたことを特徴とする請求項１に記載の歯車。2. The ribs are located on both sides of the root in the width direction of the root, and support the ends of the root in the width direction along the circumferential direction, and can be die-cut from both ends of the bearing. The gear according to claim 1, wherein auxiliary ribs are arranged so as not to overlap with each other, and auxiliary ribs connecting the ribs and the bearing portion are formed along the axial direction of the bearing portion.