JP6016357B2 - Gear and image forming apparatus - Google Patents

Gear and image forming apparatus Download PDF

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JP6016357B2
JP6016357B2 JP2011280094A JP2011280094A JP6016357B2 JP 6016357 B2 JP6016357 B2 JP 6016357B2 JP 2011280094 A JP2011280094 A JP 2011280094A JP 2011280094 A JP2011280094 A JP 2011280094A JP 6016357 B2 JP6016357 B2 JP 6016357B2
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gear
web
recesses
recess
axis
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JP2013130243A (en
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兼資 川野
兼資 川野
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Canon Inc
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Description

本発明は、複写機,プリンタ等の画像形成装置及びカメラ等の撮像装置への使用が可能な歯車構造に関するものであり、特に低振動・低騒音化を目的とする技術分野に関する。ここで画像形成装置とは紙などの記録媒体に画像を形成するものである。また撮像装置とは被写体を撮影するものである。   The present invention relates to a gear structure that can be used in an image forming apparatus such as a copying machine and a printer, and an imaging apparatus such as a camera, and more particularly to a technical field aimed at reducing vibration and noise. Here, the image forming apparatus forms an image on a recording medium such as paper. The imaging device is for photographing a subject.

稼働時の歯車の振動や騒音低減には、歯車のウエブ面の剛性をあげて歯車同士の噛み合いによるウエブ面の振動を抑えることが効果的であることが実験や解析ですでにわかっている。   Experiments and analyzes have already shown that it is effective to reduce the vibration and noise of the gear during operation by increasing the rigidity of the web surface of the gear and suppressing the vibration of the web surface due to the meshing of the gears.

図18に従来から一般的に使用されている歯車の斜視図を示す。図18(a)は歯車を一方方向から見た斜視図であり、図18(b)はその裏面図である。図18において、23は歯車、24及び26は歯車23のウエブに形成されたリブ、25及び27は歯車の基本肉厚部である。図示の如く、歯車の多くは歯車のウエブにリブを形成し歯車ウエブの剛性をあげる構成をとるが、射出成型時の引け(成形収縮によって生じるへこみ)防止や歯形精度向上のためにリブ太さを基本肉厚の50〜70%程度に設定するのが好ましい。このようにリブ太さの上限には制限あり、リブによって十分な剛性を確保することは困難であった。そのため、歯車に十分な剛性を持たせるためには歯車を大型化する必要があった。   FIG. 18 is a perspective view of a gear generally used conventionally. FIG. 18A is a perspective view of the gear viewed from one direction, and FIG. 18B is a rear view thereof. In FIG. 18, 23 is a gear, 24 and 26 are ribs formed on the web of the gear 23, and 25 and 27 are basic thick portions of the gear. As shown in the figure, many gears have a structure in which a rib is formed on the gear web to increase the rigidity of the gear web. Is preferably set to about 50 to 70% of the basic thickness. Thus, the upper limit of the rib thickness is limited, and it has been difficult to ensure sufficient rigidity by the rib. Therefore, it is necessary to enlarge the gear in order to give the gear sufficient rigidity.

そこで、歯車を大型化することなく歯車ウエブの剛性を高める提案として、以下の提案がなされている。   Therefore, the following proposal has been made as a proposal for increasing the rigidity of the gear web without increasing the size of the gear.

図19はその先行技術文献での提案例を説明する図である。円筒状に形成され外周面151aに軸に対して斜めの歯を有するリム151と、円盤状に形成されリム151の内周面151bから軸芯方向に延在するウエブ152と、軸芯に形成されたボス153と、が一体樹脂成形される。さらに、ウエブ152には軸方向の強度を補強するリム151径よりも小さな同心円の補強部154が少なくとも1つ以上形成する。これにより、リムの形状を損なうことなくウエブを補強でき、リムの断面2次モーメントを均一にするとともに充填および熱収縮の均一な樹脂成形を実現するように構成したものである(特許文献1参照)。   FIG. 19 is a diagram for explaining an example proposed in the prior art document. A rim 151 formed in a cylindrical shape having teeth oblique to the axis on the outer peripheral surface 151a, a web 152 formed in a disk shape and extending in the axial direction from the inner peripheral surface 151b of the rim 151, and formed on the shaft core The formed boss 153 is integrally molded with resin. Further, at least one concentric reinforcing portion 154 smaller than the diameter of the rim 151 for reinforcing the strength in the axial direction is formed on the web 152. Accordingly, the web can be reinforced without impairing the shape of the rim, and the second moment of the rim is made uniform, and the resin molding with uniform filling and thermal shrinkage is realized (see Patent Document 1). ).

また、他の先行技術文献では、中心部に存するハブから周縁部に存するリムまで放射状に延びる複数のリブを備えた樹脂製歯車において、ウエブ表面とウエブ裏面に形成した複数のリブの配置をずらす構成が記載されている。これにより歯車の成形時における引けを抑制し、高精度な歯車成形を実現する構成も提案されている(特許文献2参照)。   In another prior art document, in a resin gear provided with a plurality of ribs extending radially from a hub existing in the central portion to a rim existing in the peripheral portion, the arrangement of the plurality of ribs formed on the web surface and the back surface of the web is shifted. The configuration is described. In this way, a configuration has been proposed in which the shrinkage during the molding of the gears is suppressed and high-precision gear molding is realized (see Patent Document 2).

特開平7−208579号公報JP-A-7-208579 特開2004−278635号公報JP 2004-278635 A

本発明は上記従来例を更に発展させたものであり、歯車を小型に保ちつつ剛性を高めることを目的とする。   The present invention is a further development of the above conventional example, and an object thereof is to increase the rigidity while keeping the gears small.

上記目的を達成するため、本発明の代表的な構成は
円盤状のウエブと、前記ウエブの外周部に設けられた歯面を備える歯車において、
前記ウエブの一面側から窪んだ複数の一面側凹部と、
前記ウエブの他面側から窪んだ複数の他面側凹部と、
を備え、
前記一面側凹部と前記他面側凹部は前記歯車の円周方向に沿って交互に配置され、前記歯車の軸線方向において位置が重なり、
前記一面側凹部と前記他面側凹部が前記円周方向に沿って交互に配置された列が、同心円状に複数形成され、複数の前記列の内、前記歯車の最も内側に設けられた列に配置される前記一面側凹部と前記他面側凹部の合計数は、前記歯車の最も外側に設けられた列に配置される前記一面側凹部と前記他面側凹部の合計数よりも多いことを特徴とする。
In order to achieve the above object, a typical configuration of the present invention is as follows.
In a gear having a disk-shaped web and a tooth surface provided on the outer peripheral portion of the web,
A plurality of one-side recesses recessed from one side of the web;
A plurality of recesses on the other surface side that are recessed from the other surface side of the web;
With
The one-surface-side recesses and the other-surface-side recesses are alternately arranged along the circumferential direction of the gear, and the positions overlap in the axial direction of the gear,
A plurality of rows in which the one-surface-side recesses and the other-surface-side recesses are alternately arranged along the circumferential direction are formed concentrically, and among the plurality of rows, the row provided on the innermost side of the gear The total number of the one-surface-side recesses and the other-surface-side recesses disposed on the outer surface is larger than the total number of the one-surface-side recesses and the other-surface-side recesses disposed in the outermost row of the gear. It is characterized by.

本発明によれば歯車を小型に保ちつつ剛性を高めることができる。   According to the present invention, rigidity can be increased while keeping the gears small.

歯車の斜視図(実施例1)Perspective view of gear (Example 1) 歯車の斜視図(実施例1)Perspective view of gear (Example 1) 歯車の断面図(実施例1)Sectional view of gear (Example 1) 歯車駆動機構の説明図Explanation of gear drive mechanism 歯車駆動機構の説明図Explanation of gear drive mechanism 歯車駆動機構の説明図Explanation of gear drive mechanism 噛み合い時の変形概念図Deformation conceptual diagram when meshing 歯車のウエブ剛性説明図Explanation of gear rigidity of gear 歯車のウエブ剛性説明図Explanation of gear rigidity of gear 歯車のウエブ剛性説明図Explanation of gear rigidity of gear 歯車の斜視図(実施例2)Perspective view of gear (Example 2) 歯車のウエブ剛性説明図(実施例2)Explanation of the web rigidity of gears (Example 2) 歯車の斜視図(実施例3)Perspective view of gear (Example 3) 歯車の変形を説明する概念図Conceptual diagram explaining gear deformation 歯車のウエブ剛性説明図Explanation of gear rigidity of gear 本発明を適用した歯車を用いたレーザビームプリンタの説明図Explanatory drawing of a laser beam printer using a gear to which the present invention is applied 本発明を適用した歯車を用いたレーザビームプリンタの説明図Explanatory drawing of a laser beam printer using a gear to which the present invention is applied 歯車の斜視図(従来例)Perspective view of gear (conventional example) 歯車の斜視図(従来例)Perspective view of gear (conventional example) 歯車の正面図(実施例3)Front view of gear (Example 3)

(実施例1)
本発明を適用した歯車を代表的な歯車駆動機構を用いて説明する。
Example 1
A gear to which the present invention is applied will be described using a typical gear driving mechanism.

図1は本発明を適用した本実施例の歯車の斜視図であり、図1(a)は歯車正面図、図1(b)は歯車裏面図である。   FIG. 1 is a perspective view of a gear according to the present embodiment to which the present invention is applied. FIG. 1 (a) is a front view of the gear, and FIG. 1 (b) is a rear view of the gear.

図1(a)及び図1(b)において、1は本発明を適用した歯車であって、大径歯車部と小径歯車部の段ギアからなる。1aは円盤状のウエブであり、歯車1の基盤部となる。2は歯車1の外周(ウエブ1aの外周)に形成された大径歯車の歯面である。歯面2は歯車の回転軸に対して傾いた斜歯(はすば)である。   1 (a) and 1 (b), reference numeral 1 denotes a gear to which the present invention is applied, and includes a step gear having a large diameter gear portion and a small diameter gear portion. Reference numeral 1 a denotes a disk-shaped web that serves as a base portion of the gear 1. Reference numeral 2 denotes a tooth surface of a large-diameter gear formed on the outer periphery of the gear 1 (the outer periphery of the web 1a). The tooth surface 2 is an inclined tooth (helical) inclined with respect to the rotation axis of the gear.

また、3は歯車1を回転自在に支持する支持軸8(図4参照、後述)の外周部と係合するためのボス部である。ボス部3の内面には係合穴5が形成される。また、ボス部3の一部には他の歯車と噛み合う小径歯車の歯面4が形成されている。6は歯車1のウエブ1aの一面側(以下「表側」と呼ぶ)1a1に複数形成された平面部、7はウエブ1aの他面側(以下、「裏側」と呼ぶ)1a2に複数形成された平面部である。   Reference numeral 3 denotes a boss portion for engaging with an outer peripheral portion of a support shaft 8 (see FIG. 4, which will be described later) that rotatably supports the gear 1. An engagement hole 5 is formed in the inner surface of the boss portion 3. Further, a tooth surface 4 of a small-diameter gear that meshes with another gear is formed on a part of the boss portion 3. 6 is a plurality of flat portions formed on one side (hereinafter referred to as “front side”) 1a1 of the web 1a of the gear 1, and 7 is formed on the other side (hereinafter referred to as “back side”) 1a2 of the web 1a. It is a plane part.

図2は、歯車1の斜視図である。図3(a)は図2における平面A1で歯車1を切断した際の断面図である。平面A1は歯車1の回転軸の軸線f1を含む平面である。図3(b)は図2における平面A2で歯車1を切断した際の断面図である。平面A2も平面A1同様に歯車1の回転軸の軸線f1を含む面である。   FIG. 2 is a perspective view of the gear 1. FIG. 3A is a cross-sectional view of the gear 1 cut along a plane A1 in FIG. The plane A1 is a plane including the axis f1 of the rotation axis of the gear 1. FIG. 3B is a cross-sectional view of the gear 1 cut along a plane A2 in FIG. The plane A2 is also a plane including the axis f1 of the rotation axis of the gear 1 like the plane A1.

本実施例の歯車1では図3に示されるように、ウエブ1aの表側1a1に設けられた平面部6は、ウエブ1aの裏側1a2に設けられた凹部6aによって形成される。ここで凹部6aはウエブ1aの裏側1a2から窪み、表側1a1に平面部6を形成する裏側凹部(他面側凹部)である。   In the gear 1 of this embodiment, as shown in FIG. 3, the flat surface portion 6 provided on the front side 1a1 of the web 1a is formed by a recess 6a provided on the back side 1a2 of the web 1a. Here, the recess 6a is a back side recess (another side recess) that is recessed from the back side 1a2 of the web 1a and forms the flat surface part 6 on the front side 1a1.

またウエブ1aの裏側1a2に設けられた平面部7は、ウエブ1aの表側1a1に設けられた凹部7aによって形成される。ここで凹部7aはウエブ1aの表側1a1から窪み、裏側1a1に平面部7を形成する表側凹部(一面側凹部)である。凹部7aは凹部6aに対して位相が180°異なる関係になっている。   The flat surface portion 7 provided on the back side 1a2 of the web 1a is formed by a recess 7a provided on the front side 1a1 of the web 1a. Here, the concave portion 7a is a front-side concave portion (one-side concave portion) that is depressed from the front side 1a1 of the web 1a and forms the flat portion 7 on the back side 1a1. The recess 7a is in a relationship that the phase is 180 ° different from that of the recess 6a.

ここで凹部6aと凹部7aは、歯車1の軸線方向Fにおいて重なることを特徴とする。つまり、図3に示すように、歯車1の軸線f1が延びる方向(軸線方向F)において、凹部6aと凹部7aは重なる範囲Gを有する。   Here, the recess 6 a and the recess 7 a overlap with each other in the axial direction F of the gear 1. That is, as shown in FIG. 3, the recess 6 a and the recess 7 a have a range G in which the axis f <b> 1 of the gear 1 extends (axis direction F).

また本実施例ではこれら複数の平面部6及び複数の平面部7がウエブ3の円周方向(歯車1の回転方向)に沿って交互に形成されていることを特徴とする。   In the present embodiment, the plurality of plane portions 6 and the plurality of plane portions 7 are alternately formed along the circumferential direction of the web 3 (the rotation direction of the gear 1).

すなわち図1(a)に示すようにウエブ1aの表側1a1には平面部6と凹部7aがそれぞれ16個ずつ設けられ、ウエブの円周方向(矢印B1とB2で示す方向)に沿って、平面部6と凹部7aが交互に配置された円形の列を2つ形成する。つまり矢印B1に沿った列と、矢印B2に沿った列の2つの列が同心円状に形成され、一列当たり8つの平面部6と8つの凹部7aが交互に並ぶことになる。また、本実施例ではウエブ1aの半径方向C1に沿って、平面部6と凹部7aが隣接して並ぶようにした。   That is, as shown in FIG. 1A, the front side 1a1 of the web 1a is provided with 16 plane portions 6 and 16 recesses 7a, respectively, along the circumferential direction of the web (directions indicated by arrows B1 and B2). Two circular rows in which the portions 6 and the recesses 7a are alternately arranged are formed. That is, the two rows of the row along the arrow B1 and the row along the arrow B2 are formed concentrically, and the eight plane portions 6 and the eight concave portions 7a are alternately arranged per row. In the present embodiment, the flat surface portion 6 and the concave portion 7a are arranged adjacent to each other along the radial direction C1 of the web 1a.

また図1(b)に示すようにウエブ1aの裏側1a2には、平面部7と凹部6aがそれぞれ16個ずつ設けられ、ウエブ1aの円周方向に沿って、平面部7と凹部6aが交互に配置された列が2つ並ぶことになる。また、半径方向に沿って、平面部7と凹部6aが隣接する。   As shown in FIG. 1B, the back side 1a2 of the web 1a is provided with 16 plane portions 7 and 16 recesses 6a, and the plane portions 7 and the recesses 6a are alternately arranged along the circumferential direction of the web 1a. Two rows arranged in the are arranged. Further, the planar portion 7 and the recess 6a are adjacent to each other along the radial direction.

つまり本実施例の歯車1では、ウエブ1aの円周方向B1,B2に沿って、ウエブ1aの表側1a1に形成された凹部7aと、ウエブ1aの裏側1a2に形成された凹部6aが、交互に配置される。またウエブ1aの半径方向C1に沿って、凹部7aと凹部6aが交互に配置される。   That is, in the gear 1 of the present embodiment, the recesses 7a formed on the front side 1a1 of the web 1a and the recesses 6a formed on the back side 1a2 of the web 1a are alternately arranged along the circumferential direction B1, B2 of the web 1a. Be placed. Further, the concave portions 7a and the concave portions 6a are alternately arranged along the radial direction C1 of the web 1a.

本実施例では、図3に示されるように歯面2の歯筋長さ(歯幅)と、ウエブ1aの厚み(平面部6と平面部7との距離)がほぼ等しくなるまで、平面部6の高さと平面部7の高さを大きくした構成を取っている。むろん、歯車ウエブ1aの厚みを歯幅に合わせる必要はない事は言うまでもなく、駆動伝達時に必要とされる強度から適宜設定すれば良い。   In the present embodiment, as shown in FIG. 3, the length of the tooth trace 2 (tooth width) and the thickness of the web 1a (the distance between the plane portion 6 and the plane portion 7) are approximately equal to each other. 6 and the height of the flat surface portion 7 are increased. Of course, it is needless to say that the thickness of the gear web 1a does not need to be adjusted to the tooth width, and may be set as appropriate from the strength required at the time of driving transmission.

図4は本実施例の歯車を使用した歯車駆動機構の歯車列の斜視図であり、図5は正面図、図6は側面図である。図4〜図6において、8は歯車1を回転自在に保持する支持軸であって歯車1の係合穴5(図1参照)に挿入されている。9は歯車1と噛み合う駆動歯車であり、不図示の駆動機構によって回転軸10と一体となって回転し、歯車1への駆動伝達を行うものである。一方、歯車1を挟んで駆動歯車9の反対側には回転軸13に回転自在に軸支持された出力歯車11がある。出力歯車11の最外周に形成された歯面12が歯車1の小径歯車の歯面4と噛み合い、駆動源からの動力力を出力する構成となっている。   4 is a perspective view of a gear train of a gear drive mechanism using the gear of this embodiment, FIG. 5 is a front view, and FIG. 6 is a side view. 4 to 6, reference numeral 8 denotes a support shaft that rotatably holds the gear 1 and is inserted into the engagement hole 5 (see FIG. 1) of the gear 1. A drive gear 9 that meshes with the gear 1 is rotated integrally with the rotary shaft 10 by a drive mechanism (not shown) to transmit drive to the gear 1. On the other hand, on the opposite side of the drive gear 9 across the gear 1, there is an output gear 11 that is rotatably supported by a rotary shaft 13. The tooth surface 12 formed on the outermost periphery of the output gear 11 meshes with the tooth surface 4 of the small-diameter gear of the gear 1 to output power from the drive source.

ここで、本実施例の歯車1は上述したように歯面2がはすばとなるはすば歯車である。はすば歯車では歯面(歯筋)が斜めに形成されているために、他の歯車との噛み合い、回転する時には、噛み合い部において歯車のスラスト方向(図7中でE2方向)に力がかかる。この力によって、仮に図7に示すように歯車1の一部(部位Q)が変形してしまうと、他の歯車との噛み合いが正常に保たれなくなる。このとき歯車1と駆動歯車9及び出力歯車11とのアライメントに誤差が生じ、歯車1の回転が変動したり、歯車1の振動や騒音の原因になる可能性が生じる。   Here, the gear 1 of the present embodiment is a helical gear whose tooth surface 2 is helical as described above. In helical gears, the tooth surfaces (tooth traces) are formed obliquely, so when meshing with other gears and rotating, force is exerted in the gear thrust direction (E2 direction in FIG. 7) at the meshing part. Take it. If a part (part Q) of the gear 1 is deformed by this force as shown in FIG. 7, the meshing with other gears cannot be maintained normally. At this time, an error occurs in the alignment of the gear 1 with the drive gear 9 and the output gear 11, and the rotation of the gear 1 may fluctuate, or the gear 1 may vibrate or cause noise.

ここで従来型の歯車23(図18参照)を用いて、歯車の変形と歯車が生じる騒音の関係について調べたので以下に説明する。図8は、従来の歯車23を回転させた時に、ウエブの倒れ角度(=ウエブの変形量)と、歯車23から生じる騒音との関係を示すグラフである。即ち、剛性を異ならせた歯車23を複数用意し、それぞれの歯車を同様の条件で回転させた際の、歯車の変形と、歯車から生じる騒音の関係を示したものである。   Here, the relationship between the deformation of the gear and the noise generated by the gear is examined using the conventional gear 23 (see FIG. 18), which will be described below. FIG. 8 is a graph showing the relationship between the web tilt angle (= the amount of deformation of the web) and the noise generated from the gear 23 when the conventional gear 23 is rotated. That is, the relationship between the deformation of the gear and the noise generated from the gear when rotating a plurality of gears 23 with different rigidity and rotating under the same conditions is shown.

実験条件として、歯車23を毎分3000回転させた時の騒音を測定することとした。また歯車から生じる騒音を、ウエブの倒れ角度が0°となる場合を基準として、そこからの増分で示した。またウエブの倒れ角度は、シミュレーションにより計算で測定してある。   As an experimental condition, the noise when the gear 23 was rotated 3000 per minute was measured. Also, the noise generated from the gears is shown in increments from the case where the web tilt angle is 0 °. The web tilt angle is measured by simulation.

図8より明らかなように歯車ウエブ面の倒れ角度の増加に伴い、歯車による騒音も増大する事が分かっている。   As is apparent from FIG. 8, it is known that the noise caused by the gears increases as the tilt angle of the gear web surface increases.

図9に、FEM計算で求めた、歯車の変形状態図を示す。他の歯車と噛み合い、回転する時には歯車23の一部の領域(部位Q2)が矢印E1方向に大きく変形し、アライメント誤差を生じさせ、振動や騒音を増大させている事が確認できる。   FIG. 9 shows a deformation state diagram of the gear obtained by FEM calculation. It can be confirmed that when meshing with other gears and rotating, a partial region (part Q2) of the gear 23 is greatly deformed in the direction of the arrow E1, causing an alignment error and increasing vibration and noise.

この振動や騒音を低減させるためには、歯車の剛性をあげ、歯車の変形量を小さくすることが求められる。従来は、歯車の剛性を上げるために、歯幅を大きく取ってウエブの厚みを厚くする、歯車の基本肉厚を厚くするなどの手段が取られていた。しかし、それぞれで課題を有している。つまり歯車のウエブを厚くすると歯車を用いる機器も大型化してしまう。また、歯車の基本肉厚を厚くすると歯車の成型時に、収縮によってへこみができる、所謂ひけ問題が生じやすくなり、高精度の歯車を製造する事ができなくなる。   In order to reduce this vibration and noise, it is required to increase the rigidity of the gear and reduce the deformation amount of the gear. Conventionally, in order to increase the rigidity of the gear, measures such as increasing the tooth width to increase the thickness of the web and increasing the basic thickness of the gear have been taken. However, each has problems. In other words, when the gear web is thickened, the equipment using the gear is also enlarged. Further, when the basic thickness of the gear is increased, a so-called sink problem that can be caused by dents due to shrinkage during molding of the gear is likely to occur, and a high-precision gear cannot be manufactured.

そこで本実施例では、上記の課題を生じさせることなくウエブの剛性を高められる形状の歯車1を提供する。   Therefore, in this embodiment, a gear 1 having a shape that can increase the rigidity of the web without causing the above-described problems is provided.

すなわち本実施例では歯車1においてウエブ1aの剛性を高める手段として、図1で示したように、ウエブ1aの半径方向及び円周方向において、凹部7a(平面部7)と凹部6a(平面部6)を交互に配置したことを特徴とする。これにより、ウエブ1aの剛性を上げることができる。なお本実施例では、歯車1の剛性を全体で均一にするうえでウエブ1aに形成する凹部7aと凹部6aの個数を同数とした。   That is, in this embodiment, as a means for increasing the rigidity of the web 1a in the gear 1, as shown in FIG. 1, in the radial direction and the circumferential direction of the web 1a, the concave portion 7a (the flat portion 7) and the concave portion 6a (the flat portion 6). ) Are arranged alternately. Thereby, the rigidity of the web 1a can be increased. In this embodiment, in order to make the rigidity of the gear 1 uniform as a whole, the number of the recesses 7a and the recesses 6a formed in the web 1a is the same.

図10に従来の歯車23(図18参照)のウエブと本実施例の歯車1のウエブ1aの剛性比較を示す。このグラフは歯車23と歯車1の歯面に同条件で力をかけた場合のウエブの変形量を計算で求め、比較したものである。   FIG. 10 shows a rigidity comparison between the web of the conventional gear 23 (see FIG. 18) and the web 1a of the gear 1 of the present embodiment. This graph is obtained by calculating and comparing the deformation amount of the web when force is applied to the tooth surfaces of the gear 23 and the gear 1 under the same conditions.

ここでは、歯車に使用される材料の体積と、歯車の大きさをほぼ同一にした条件で、従来の歯車23と本実施例における歯車1を比較している。その結果、本発明の歯車1では従来の歯車23に比較して約41%も変形量を低減する結果を得た。この事より、本実施例の歯車1の形状は剛性アップの観点から、従来に比較して非常に優位であると思われる。   Here, the conventional gear 23 and the gear 1 in the present embodiment are compared under the condition that the volume of the material used for the gear and the size of the gear are substantially the same. As a result, in the gear 1 of the present invention, the deformation amount was reduced by about 41% as compared with the conventional gear 23. From this, it is considered that the shape of the gear 1 of this embodiment is very superior to the conventional one from the viewpoint of increasing the rigidity.

また、逆に歯車1の剛性を従来同等に維持させた条件では、使用する材料を減少させることが可能である。この事は、機器の小型化やエコロジーの観点からも非常に有効なものと考えられる。   On the other hand, under the condition that the rigidity of the gear 1 is maintained at the same level as the conventional one, it is possible to reduce the material to be used. This is considered to be very effective from the viewpoint of miniaturization of equipment and ecology.

また、一般に歯車を熱可塑性樹脂で成形する場合には、成形時の収縮によって歯車にへこみが生じること(引け)を抑制するため、歯車の基本肉厚を薄くすることが望ましい。本実施例における歯車1は、歯車の剛性を高くしつつ、歯車の基本肉厚を薄くすることができるので、成形時にへこみが生じることを抑制できる。すなわち歯車1を熱可塑性樹脂で成形した場合にも、歯車1の寸法を高精度に保つことができる。   In general, when a gear is molded from a thermoplastic resin, it is desirable to reduce the basic thickness of the gear in order to prevent the gear from being dented (shrunk) due to shrinkage during molding. Since the gear 1 in the present embodiment can reduce the basic thickness of the gear while increasing the rigidity of the gear, the occurrence of dents during molding can be suppressed. That is, even when the gear 1 is formed of a thermoplastic resin, the dimension of the gear 1 can be maintained with high accuracy.

(実施例2)
図11に本発明の第2の実施例を示す。図11の歯車14及び歯車16は歯車の一面側に形成される平面部と凹部によって歯車の一面側が分割される分割数、すなわち歯車の表側凹部(一面側凹部)と裏側凹部(他面側凹部)の合計数を実施例1よりも増やしたものである。基本的な構造は実施例1の歯車と同じなので詳細な説明は省略する。
(Example 2)
FIG. 11 shows a second embodiment of the present invention. The gears 14 and 16 shown in FIG. 11 are divided into the number of divisions on one side of the gear by a flat part and a concave part formed on one side of the gear, that is, the front side concave part (one side concave part) and the back side concave part (other side concave part). ) Is greater than that of the first embodiment. Since the basic structure is the same as that of the gear of the first embodiment, a detailed description is omitted.

図11(a)に示す歯車14は、円周方向を24分割するように、その表側に平面部と凹部を形成したものである。すなわち、歯車14の表側には凹部15aと平面部15bが交互に並んで円形の列を同心円状に2列形成している。これらの列には、1列あたり12個の凹部15aと12個の平面部15bが交互に配置されることで、歯車14を円周方向において24分割している。   The gear 14 shown in FIG. 11A has a plane portion and a recess formed on the front side so as to divide the circumferential direction into 24 parts. That is, on the front side of the gear 14, the concave portions 15 a and the flat portions 15 b are alternately arranged to form two circular rows concentrically. In these rows, twelve concave portions 15a and twelve planar portions 15b are alternately arranged per row, so that the gear 14 is divided into 24 in the circumferential direction.

また凹部15aと平面部15bは歯車14の半径方向に1つづつ配置され、歯車14を半径方向に2分割している。なお、ここで平面部15bは、実施例1の平面部6と同様に、歯車14の裏側に設けられた凹部(他面側凹部)によって形成されている。   The concave portions 15a and the flat portions 15b are arranged one by one in the radial direction of the gear 14, and the gear 14 is divided into two in the radial direction. In addition, the plane part 15b is formed by the recessed part (other surface side recessed part) provided in the back side of the gearwheel 14 here similarly to the plane part 6 of Example 1. FIG.

また図11(b)に示す歯車16は円周方向を24分割し、且つ半径方向を4分割するように、平面部と凹部を形成している。すなわち、歯車16の表側には凹部17aと平面部17bが交互に並んで円形の列を形成している。歯車16ではこの列が同心円状に4つ形成されることで、歯車16は半径方向に4分割されている。   Further, the gear 16 shown in FIG. 11 (b) has a flat portion and a concave portion so that the circumferential direction is divided into 24 and the radial direction is divided into four. That is, on the front side of the gear 16, the concave portions 17 a and the flat portions 17 b are alternately arranged to form a circular row. In the gear 16, four such rows are formed concentrically so that the gear 16 is divided into four in the radial direction.

すなわち、歯車16の円周方向に、12個の凹部17aと12個の平面部17bが交互に並ぶことで、歯車16を円周方向に24分割する。また歯車16の中心部から半径方向に2つの凹部17aと2つの平面部17bが交互に並ぶことで、歯車16を径方向に4分割している。   In other words, the twelve concave portions 17a and the twelve planar portions 17b are alternately arranged in the circumferential direction of the gear 16, thereby dividing the gear 16 into 24 in the circumferential direction. Further, the gear 16 is divided into four in the radial direction by alternately arranging the two concave portions 17a and the two flat portions 17b in the radial direction from the center of the gear 16.

なお、ここで平面部17bは、実施例1の平面部6と同様に、歯車16の裏側に設けられた凹部(他面側凹部)によって形成されている。   In addition, the plane part 17b is formed by the recessed part (other surface side recessed part) provided in the back side of the gearwheel 16 here similarly to the plane part 6 of Example 1. FIG.

一般的には円周方向及び半径方向ともに、ウエブの分割数を増やすと歯車のウエブ剛性はより一層高めることができると思われる。それを確認するために、歯車のウエブ剛性をFEM計算で比較した。   In general, it is considered that the web rigidity of the gear can be further increased by increasing the number of web divisions in both the circumferential direction and the radial direction. In order to confirm this, the web stiffness of gears was compared by FEM calculation.

この結果を図12に示す。図12において、左より従来例の歯車23(図18参照)、実施例1の歯車1(図1参照)、本実施例の歯車14(図11(a)参照)、本実施例の歯車16(図11(b)参照)のウエブの剛性を計算した結果である。それぞれの歯車に力を加えた際の変形量を棒グラフで示し、またそれぞれの歯車の体積を破線で示した。   The result is shown in FIG. In FIG. 12, from the left, the conventional gear 23 (see FIG. 18), the gear 1 of the first embodiment (see FIG. 1), the gear 14 of the present embodiment (see FIG. 11A), and the gear 16 of the present embodiment. It is the result of having calculated the rigidity of the web (refer to Drawing 11 (b)). The amount of deformation when a force is applied to each gear is indicated by a bar graph, and the volume of each gear is indicated by a broken line.

図12に示す様に、歯車1(図1)に比べて歯車14(図11(a))の方が、歯車に力を加えた際の変形量が小さく、剛性が高いことがわかる。また、歯車1、歯車14よりも歯車16(図11(b))の方がさらに剛性が高い。   As shown in FIG. 12, it can be seen that the gear 14 (FIG. 11A) has a smaller deformation amount and higher rigidity when a force is applied to the gear than the gear 1 (FIG. 1). Further, the gear 16 (FIG. 11B) has higher rigidity than the gears 1 and 14.

つまり円周方向及び半径方向でウエブの分割数を増やすこと(歯車に形成する凹部と平面部の数を増やすこと)によって、より歯車のウエブ剛性をあげる(歯車の変形量を低減させる)事が可能となってくる。これにより、歯車の駆動時に生じる振動や騒音を低減させる事が可能となる。   In other words, by increasing the number of web divisions in the circumferential direction and radial direction (increasing the number of recesses and flat portions formed in the gear), the web rigidity of the gear can be increased (the amount of deformation of the gear can be reduced). It becomes possible. Thereby, it becomes possible to reduce the vibration and noise which are generated when the gear is driven.

ただし図12に示す破線から分かるように、歯車14、歯車16は歯車1よりも体積が大きい。つまりウエブの分割数を増やすことで歯車の体積は大きくなる傾向がある。よって歯車に求められる体積および剛性の条件から、適宜、ウエブの分割数を選択すると良い。   However, as can be seen from the broken line shown in FIG. 12, the gears 14 and 16 have a larger volume than the gear 1. In other words, the volume of the gear tends to increase by increasing the number of web divisions. Therefore, the number of web divisions may be appropriately selected from the volume and rigidity conditions required for the gear.

なお、一般的な歯車は、歯車の外周に形成された歯面で噛み合うものが多い。その場合、噛み合いにより歯面に力がかかり、その力により歯車のウエブが変形する。この変形量を抑えるには、歯車内周側のウエブ剛性を上げる事で、曲げモーメントに対して歯車を強くすることが考えられる。   Note that many common gears mesh with a tooth surface formed on the outer periphery of the gear. In that case, a force is applied to the tooth surface by the meshing, and the gear web is deformed by the force. In order to suppress this deformation, it is conceivable to increase the gear rigidity against the bending moment by increasing the web rigidity on the inner peripheral side of the gear.

ここで、円周方向におけるウエブの分割数に関して、内周側の分割数を外周側の分割数よりも多くさせる事で、歯車のウエブ剛性を高めることができる。歯車16(図11(b)参照)のように、半径方向に歯車が3分割以上される場合は、歯車の最も内側における円周方向の分割数を、歯車の最も外側における円周方向の分割数よりも大きくするとよい。   Here, regarding the number of divisions of the web in the circumferential direction, the web rigidity of the gear can be increased by making the number of divisions on the inner circumferential side larger than the number of divisions on the outer circumferential side. When the gear is divided into three or more in the radial direction as in the gear 16 (see FIG. 11B), the number of divisions in the circumferential direction on the innermost side of the gear is set to the division in the circumferential direction on the outermost side of the gear. It should be larger than the number.

なお、実施例1及び本実施例での歯車1、14,16は、はすば歯車を前提として説明してきたが、平歯歯車でも本実施例の構成を取ることでウエブ剛性を上げる効果がある。   The gears 1, 14, and 16 in the first embodiment and the present embodiment have been described on the assumption of a helical gear, but even a spur gear has the effect of increasing the web rigidity by adopting the configuration of the present embodiment. is there.

しかし、はすば歯車の場合は、歯面がネジレ角を有し、歯面(歯筋)が歯車の軸線(回転軸)に対して斜めになっている為に、歯車の回転時にスラスト方向に大きな力がかかる。そのためはすば歯車へ上述の構成を適用することが、本発明の効果をより一層得る上では望ましい。   However, in the case of helical gears, the tooth surface has a twist angle, and the tooth surface (tooth trace) is inclined with respect to the gear axis (rotation axis), so the thrust direction when the gear rotates. It takes a lot of power. Therefore, it is desirable to apply the above-described configuration to a helical gear in order to further obtain the effects of the present invention.

(実施例3)
図13に本発明の第3の実施例を示す。図13(a)は本実施例の歯車18を表側からみた斜視図である。図13(b)は歯車18を裏側からみた斜視図である。
(Example 3)
FIG. 13 shows a third embodiment of the present invention. FIG. 13A is a perspective view of the gear 18 of this embodiment as viewed from the front side. FIG. 13B is a perspective view of the gear 18 as seen from the back side.

図13において、歯車18ははすば歯車であって、実施例1の歯車同様にウエブの両側に互いに位相をずらした凹部19及び凹部21を有する構成の歯車である。しかし実施例1と異なり、凹部19の側面を形成する壁面(以下、「傾斜面」と呼ぶ)20と凹部21の側面を形成する壁面(以下、「傾斜面」と呼ぶ)22を、図14に示すように歯車18の軸線d1に対して斜めに構成している事が特徴である。ここで図14ははすば歯車のネジレ角と傾斜面との関係を示す概念図である。   In FIG. 13, the gear 18 is a helical gear, and is a gear having a concave portion 19 and a concave portion 21 that are out of phase with each other on both sides of the web, like the gear of the first embodiment. However, unlike the first embodiment, the wall surface (hereinafter referred to as “inclined surface”) 20 that forms the side surface of the recess 19 and the wall surface (hereinafter referred to as “inclined surface”) 22 that forms the side surface of the recess 21 are shown in FIG. As shown in FIG. 4, the configuration is oblique with respect to the axis d1 of the gear 18. FIG. 14 is a conceptual diagram showing the relationship between the helical angle of the helical gear and the inclined surface.

図13、14に示すように傾斜面20及び傾斜面22は歯車18の歯面(はすば)18cと略直交する方向に形成されている。この傾斜面20及び傾斜面22は、はすば歯車である歯車18が、駆動時に受けるスラスト方向の力に対し、より剛性を保つために形成されてある。   As shown in FIGS. 13 and 14, the inclined surface 20 and the inclined surface 22 are formed in a direction substantially orthogonal to the tooth surface (helical) 18 c of the gear 18. The inclined surface 20 and the inclined surface 22 are formed in order that the gear 18 which is a helical gear maintains more rigidity against the thrust force received during driving.

つまりはすば歯車である歯車18は、回転時に歯面(はすば)18cと直交する方向に力が加わる。そこで、図14に示すようにこの歯面18cに対して直交するように傾斜面20、22を設ければ、歯車の実効歯幅を大きくさせる事と同等の効果を得る事ができる。   In other words, the gear 18 which is a helical gear applies a force in a direction perpendicular to the tooth surface (helical) 18c during rotation. Therefore, as shown in FIG. 14, if the inclined surfaces 20 and 22 are provided so as to be orthogonal to the tooth surface 18c, an effect equivalent to increasing the effective tooth width of the gear can be obtained.

はすば歯車のネジレ角は一般的には10〜30度程度とる場合が多い。そのため、この傾斜面20、22の傾斜角度は、歯面(はすば)18cに略直交する様に30〜60度程度取る事が望ましい。   The helical angle of a helical gear is generally about 10 to 30 degrees. Therefore, it is desirable that the inclination angles of the inclined surfaces 20 and 22 be about 30 to 60 degrees so as to be substantially orthogonal to the tooth surface (helical) 18c.

図15にFEM計算で歯車のウエブ剛性を確認したデータを示す。図15では「はすばのネジレ角と逆方向」で傾斜面を形成した場合と、「はすばのネジレ角と同一方向」で傾斜面を形成した場合とを比較している。   FIG. 15 shows data obtained by confirming the web rigidity of the gear by FEM calculation. In FIG. 15, the case where the inclined surface is formed in “the direction opposite to the helical twist angle” is compared with the case where the inclined surface is formed in the “same direction as the helical twist angle”.

傾斜面を「はすばのネジレ角と逆方向」に形成した場合とは図14のように傾斜面20(22)を歯面18cと交差(直交)する様に傾斜した場合であって、これが本実施例の歯車18の構成にあたる。   The case where the inclined surface is formed in the “opposite direction to the helical twist angle” is a case where the inclined surface 20 (22) is inclined so as to intersect (orthogonal) the tooth surface 18c as shown in FIG. This corresponds to the configuration of the gear 18 of the present embodiment.

一方、傾斜面を「はすばのネジレ角と同一方向」に形成した場合とは、歯面(はすば)18cの傾きに沿って傾斜面22を傾斜した場合であり、これを本実施例に対する比較例とした。   On the other hand, the case where the inclined surface is formed in “the same direction as the helical twist angle” is a case where the inclined surface 22 is inclined along the inclination of the tooth surface (helical) 18c. It was set as the comparative example with respect to the example.

上記2つの歯車の剛性を比較するため、図20に示すように、歯車の各点R1‐R9に力を加えた際の、歯車の変形量をそれぞれFEM計算にて求めた。なお図20は本実施例における歯車18の正面図である。   In order to compare the rigidity of the two gears, as shown in FIG. 20, the amount of deformation of the gear when a force was applied to each point R1-R9 of the gear was determined by FEM calculation. FIG. 20 is a front view of the gear 18 in this embodiment.

図15において白抜きの点(□)が、傾斜面を「はすばのネジレ角と逆方向」に形成した本実施例を表す点であり、黒塗りの点(◆)が、傾斜面を「はすばのネジレ角と同一方向」に形成した比較例を表す点である。   In FIG. 15, white dots (□) are points representing this example in which the inclined surface is formed in the “opposite direction to the helical twist angle”, and the black dots (♦) indicate the inclined surface. This is a point representing a comparative example formed in the “same direction as the helical twist angle”.

グラフ縦軸は、図20のR1−R9に、スラスト方向(図20において図面の裏から表に向かう方向)に力を加えた際の歯車の変形量をそれぞれ計算で求め、ミリメートルで示したものである。   The vertical axis of the graph shows the amount of gear deformation when the force is applied to R1-R9 in FIG. 20 in the thrust direction (the direction from the back of the drawing to the front in FIG. 20), and is shown in millimeters. It is.

グラフ横軸は、歯車に力を加えた位置、すなわち図20におけるR1、R2、R3…R9を角度で示したものである。R1を基準として0°にとり、R2の角度θが5°に対応する。また、R3、R4…R9が、それぞれ5°刻みで、10°、15°…40°に対応する。   The horizontal axis of the graph indicates the position where the force is applied to the gear, that is, R1, R2, R3... R9 in FIG. Taking R1 as a reference, the angle is 0 °, and the angle θ of R2 corresponds to 5 °. R3, R4,... R9 correspond to 10 °, 15 °,.

図15から分かるように、傾斜面を「はすばのネジレ角と逆方向」に形成した本実施例の方が、歯車の変形量も小さくなり、歯車ウエブ面の剛性が上がっている事を確認できる。   As can be seen from FIG. 15, the present embodiment in which the inclined surface is formed in the “opposite direction of the helical torsion angle” also reduces the amount of deformation of the gear and increases the rigidity of the gear web surface. I can confirm.

この様に、実施例1の構成に加え、更に凹部に傾斜面を形成させることで、より低振動及び低騒音の歯車を提供する事が可能となる。   In this manner, in addition to the configuration of the first embodiment, it is possible to provide a gear with lower vibration and noise by forming an inclined surface in the recess.

なお傾斜面20、22を歯面(はすば)18cと直交させることが最も望ましいが、必ずしもこれに限る必要はない。傾斜面20、22が歯車18の軸線d1に対して傾斜する向きが、歯車18の歯面(はすば)18cが軸線d1に対して傾斜する向きの反対であるとよい。   Although it is most desirable to make the inclined surfaces 20 and 22 orthogonal to the tooth surface (helical) 18c, it is not necessarily limited to this. The direction in which the inclined surfaces 20 and 22 are inclined with respect to the axis d1 of the gear 18 is preferably opposite to the direction in which the tooth surface (helical) 18c of the gear 18 is inclined with respect to the axis d1.

つまり、図14に示すように歯車18を軸線d1が水平になるように配置し、軸線d1と直交する向きからみたときに、歯面(はすば)18cが軸線d1に対して右下がりに傾く場合は、傾斜面20(22)を軸線d1に対して右上がりに傾かせるとよい。またこれとは逆に歯面(はすば)18cが右上がりに傾く場合は、傾斜面20(22)を右下がりに傾斜させると良い。   That is, as shown in FIG. 14, when the gear 18 is arranged so that the axis d1 is horizontal and viewed from a direction orthogonal to the axis d1, the tooth surface (claw) 18c is lowered to the right with respect to the axis d1. In the case of inclining, the inclined surface 20 (22) may be inclined upward to the right with respect to the axis d1. On the other hand, when the tooth surface (claw) 18c is inclined upward to the right, the inclined surface 20 (22) is preferably inclined downward to the right.

なお本実施例では、歯車18の成形時に、収縮によってへこみができること(ひけ)を防止するため、歯車18の表側に設けた凹部19と、裏側に設けた凹部21の両方にそれぞれ傾斜面20、22を設けた。しかし、凹部19と凹部21のどちらか一方に傾斜面を形成してもよい。   In the present embodiment, when the gear 18 is molded, in order to prevent dents due to contraction (sinking), both the concave portion 19 provided on the front side of the gear 18 and the concave portion 21 provided on the back side have inclined surfaces 20, respectively. 22 was provided. However, an inclined surface may be formed in one of the recess 19 and the recess 21.

(歯車の適用例)
次に本発明を適用した歯車からなる駆動機構をレーザビームプリンタの駆動機構に適用した事例を示す。
(Application examples of gears)
Next, an example in which the drive mechanism composed of gears to which the present invention is applied is applied to the drive mechanism of a laser beam printer will be described.

図16は、本実施形態にかかる画像形成装置の一例たるレーザビームプリンタ100の概略構成を示す断面図である。レーザビームプリンタ100は、記録材たる記録シートPを収納するデッキ101、このデッキ101内から記録シートPを繰り出すピックアップローラ102を有する。   FIG. 16 is a cross-sectional view illustrating a schematic configuration of a laser beam printer 100 as an example of an image forming apparatus according to the present embodiment. The laser beam printer 100 includes a deck 101 that stores a recording sheet P that is a recording material, and a pickup roller 102 that feeds the recording sheet P out of the deck 101.

更にレーザビームプリンタ100は、上記ピックアップローラ102によって繰り出された記録シートPを搬送するデッキ給紙ローラ103、そのデッキ給紙ローラ103と対をなし記録シートPの重送を防止するためのリタードローラ104を有する。そして、デッキ給紙ローラ103が記録シートPを搬送する搬送方向の下流側には、給紙搬送ローラ105とレジストレーションローラ対106が配設されている。   Further, the laser beam printer 100 includes a deck sheet feeding roller 103 that conveys the recording sheet P fed out by the pickup roller 102, and a retard roller that forms a pair with the deck sheet feeding roller 103 to prevent double feeding of the recording sheet P. 104. A paper feed conveyance roller 105 and a registration roller pair 106 are disposed on the downstream side in the conveyance direction in which the deck paper supply roller 103 conveys the recording sheet P.

給紙搬送ローラ105は、デッキ給紙ローラ103よりも更に記録シートPを下流へ搬送する。またレジストレーションローラ対106は、記録シートPを画像形成動作と同期して搬送する。又、レジストレーションローラ対106の下流には、後述するレーザスキャナ部107からのレーザ光に基づいて感光体ドラム108上にトナー像を形成する画像形成手段を構成するプロセスカートリッジCが装置本体に対して着脱可能に装着されている。   The sheet feeding and conveying roller 105 conveys the recording sheet P further downstream than the deck sheet feeding roller 103. The registration roller pair 106 conveys the recording sheet P in synchronization with the image forming operation. Further, downstream of the registration roller pair 106, a process cartridge C constituting image forming means for forming a toner image on the photosensitive drum 108 based on a laser beam from a laser scanner unit 107 (to be described later) is connected to the apparatus main body. And is detachably mounted.

このプロセスカートリッジCは、回転可能な感光体ドラム108と、その周囲に帯電ローラ109及び現像器110、更にはクリーニング器(図示せず)が設けられている。プロセスカートリッジCは画像形成に帯電ローラ109によって感光体ドラム108の表面を一様に帯電する。そして、レーザービームプリンタ100の装置本体に設けられたレーザスキャナ部107から、感光体ドラム108に選択的な露光を行う。これにより感光体ドラム108上に潜像(静電潜像)を形成し、そしてこの潜像を現像器110によってトナーで現像して可視像化する。そして、転写ローラ111に転写バイアス電圧を印加することで搬送されてきた記録シートPに上記トナー像を転写して画像を形成する。   The process cartridge C includes a rotatable photosensitive drum 108, a charging roller 109, a developing device 110, and a cleaning device (not shown) around the photosensitive drum 108. The process cartridge C uniformly charges the surface of the photosensitive drum 108 by the charging roller 109 for image formation. Then, the photosensitive drum 108 is selectively exposed from the laser scanner unit 107 provided in the main body of the laser beam printer 100. As a result, a latent image (electrostatic latent image) is formed on the photosensitive drum 108, and this latent image is developed with toner by the developing device 110 to be visualized. Then, by applying a transfer bias voltage to the transfer roller 111, the toner image is transferred to the recording sheet P that has been conveyed to form an image.

更に、転写ローラ111の下流には、搬送ガイド112、記録シートP上に転写されたトナー像を熱定着する定着装置113が設けられている。尚、この定着装置113はシート分離装置を備えたものである。   Further, downstream of the transfer roller 111, a conveyance guide 112 and a fixing device 113 that thermally fixes the toner image transferred onto the recording sheet P are provided. The fixing device 113 includes a sheet separating device.

その後、記録シートPは、搬送ローラ対114により排出ローラ115に送られ、次いで排出ローラ115により装置本体上面の排出トレイ116上に排出され、これで一連のプロセスが完了する。   Thereafter, the recording sheet P is sent to the discharge roller 115 by the conveying roller pair 114, and then discharged onto the discharge tray 116 on the upper surface of the apparatus main body by the discharge roller 115, thereby completing a series of processes.

ここで、前述した感光体ドラム108やそれと一体的に機能(回転等)して帯電露光を行うプロセスカートリッジの駆動機構は、近年の画質に伴い非常に高精度の回転精度が要求される。この様な駆動系には一般的にブラシレスモータと歯車駆動機構から構成されるが、稼働時には駆動モータや歯車駆動部の歯車噛合いを起振源とした振動がドラム等に影響を与え画質を乱す主要な要因でもある。そこで、本発明ではこのプロセスカートリッジの駆動系に本歯車の構造を適用し、低振動化を図っている。   Here, the photosensitive drum 108 and the process cartridge drive mechanism that performs charging exposure by functioning (rotating or the like) integrally with the photosensitive drum 108 are required to have a very high rotational accuracy in accordance with recent image quality. Such a drive system is generally composed of a brushless motor and a gear drive mechanism. During operation, the vibration generated by the meshing of the drive motor and the gear drive unit affects the drum and the like. It is also a major factor disturbing. Therefore, in the present invention, the structure of the gear is applied to the drive system of the process cartridge to reduce the vibration.

次に図17に、本発明の歯車を前記レーザビームプリンタのドラム駆動部に適用した模式図を示す。   Next, FIG. 17 shows a schematic diagram in which the gear of the present invention is applied to the drum drive unit of the laser beam printer.

図17において、108は感光体ドラム、131は感光体ドラムを回転自在に保持するドラム軸、132は感光体ドラムを駆動せしめる、はすば歯車であってドラム軸131に取り付けられる。133は駆動源としてのモータ、134は前記モータ133や前記ドラム軸131を保持する構造板金、135は前記はすば歯車132と噛合うモータピニオンである。はすば歯車132に、上述した実施例の歯車(歯車1、14、16、18のいずれか)の構成を採用した。   In FIG. 17, 108 is a photosensitive drum, 131 is a drum shaft that rotatably holds the photosensitive drum, and 132 is a helical gear that drives the photosensitive drum, and is attached to the drum shaft 131. 133 is a motor as a driving source, 134 is a structural sheet metal that holds the motor 133 and the drum shaft 131, and 135 is a motor pinion that meshes with the helical gear 132. The helical gear 132 employs the configuration of the gear (any one of the gears 1, 14, 16, and 18) of the above-described embodiment.

図17に示した如く、駆動源であるモータ133が回転するとモータ軸の先端に圧入(又は一体的にモータ軸に形成)されたモータピニオン135が回転し、その回転に伴いはすば歯車132が回転して感光体ドラム108が所定の回転数で回転する構成である。   As shown in FIG. 17, when the motor 133 as a drive source rotates, the motor pinion 135 press-fitted (or integrally formed on the motor shaft) to the tip of the motor shaft rotates, and along with the rotation, the helical gear 132 is rotated. And the photosensitive drum 108 rotates at a predetermined rotation speed.

近年のレーザビームプリンタは画質とプロセススピード(印刷速度)の両立は必須の機能でもあり、駆動モータの回転数も高くする設計がなされている。しかし、駆動モータの回転数に伴い、振動や騒音が大きくなり卓上に設置する場合にユーザに不快感を与える可能性もあった。   In recent laser beam printers, compatibility between image quality and process speed (printing speed) is an essential function, and the number of rotations of the drive motor is designed to be high. However, vibration and noise increase with the rotational speed of the drive motor, which may cause discomfort to the user when installed on a desktop.

そこで、本発明の歯車を適用する事により振動や騒音の増加を最小限に抑える事が可能となり、快適なオフィス環境を提供する事が可能になってくると考える。   Therefore, by applying the gear of the present invention, it is possible to minimize the increase in vibration and noise, and to provide a comfortable office environment.

なお感光体ドラム108に駆動力を伝えるはすば歯車132に本発明を適用したが、感光体ドラムに作用するプロセス手段や紙を搬送させる給紙機構などに駆動力を伝える歯車に本発明を適用してもよい事は言うまでもない。   Although the present invention is applied to the helical gear 132 that transmits the driving force to the photosensitive drum 108, the present invention is applied to a gear that transmits the driving force to a process unit that acts on the photosensitive drum and a paper feed mechanism that transports paper. Needless to say, it may be applied.

1 歯車(第1実施例)
2 歯面
4 歯面
6、7 平面部(実施例1)
14、16 歯車(実施例2)
15、17 平面部(実施例2)
18 歯車(実施例3)
20、22 傾斜面
23 歯車(従来例)
1 Gear (first embodiment)
2 tooth surface 4 tooth surface 6, 7 plane part (Example 1)
14, 16 Gears (Example 2)
15, 17 plane part (Example 2)
18 Gear (Example 3)
20, 22 Inclined surface 23 Gear (Conventional example)

Claims (10)

円盤状のウエブと、前記ウエブの外周部に設けられた歯面を備える歯車において、
前記ウエブの一面側から窪んだ複数の一面側凹部と、
前記ウエブの他面側から窪んだ複数の他面側凹部と、
を備え、
前記一面側凹部と前記他面側凹部は前記歯車の円周方向に沿って交互に配置され、前記歯車の軸線方向において位置が重なり、
前記一面側凹部と前記他面側凹部が前記円周方向に沿って交互に配置された列が、同心円状に複数形成され、複数の前記列の内、前記歯車の最も内側に設けられた列に配置される前記一面側凹部と前記他面側凹部の合計数は、前記歯車の最も外側に設けられた列に配置される前記一面側凹部と前記他面側凹部の合計数よりも多いことを特徴とする歯車。
In a gear having a disk-shaped web and a tooth surface provided on the outer peripheral portion of the web,
A plurality of one-side recesses recessed from one side of the web;
A plurality of recesses on the other surface side that are recessed from the other surface side of the web;
With
The other side recess and said one surface recess are arranged alternately along the circumferential direction of the gear, Ri position Do heavy in the axial direction of the gear,
A plurality of rows in which the one-surface-side recesses and the other-surface-side recesses are alternately arranged along the circumferential direction are formed concentrically, and among the plurality of rows, the row provided on the innermost side of the gear The total number of the one-surface-side recesses and the other-surface-side recesses disposed on the outer surface is larger than the total number of the one-surface-side recesses and the other-surface-side recesses disposed in the outermost row of the gear. A gear characterized by
前記一面側凹部と前記他面側凹部は、前記歯車の中心部から前記歯車の半径方向に沿って交互に配置されることを特徴とする請求項に記載の歯車。 2. The gear according to claim 1 , wherein the one-surface-side concave portion and the other-surface-side concave portion are alternately arranged along a radial direction of the gear from a central portion of the gear. 前記歯車は前記歯面がはすばとなった、はすば歯車であることを特徴とする請求項1又は2に記載の歯車。 The gear according to claim 1 or 2, wherein the gear is a helical gear having a helical tooth surface. 前記一面側凹部または前記他面側凹部の少なくとも一方の凹部は、前記一方の凹部の一部を形成し、前記歯車の軸線に対して傾斜する傾斜面を有し、
前記傾斜面は前記歯車の軸線に対して、前記歯面が前記歯車の軸線に対して傾く向きとは反対側に傾き、前記歯面と交差することを特徴とする請求項3に記載の歯車。
At least one recess of the one-surface-side recess or the other-surface-side recess forms a part of the one recess, and has an inclined surface that is inclined with respect to the axis of the gear,
4. The gear according to claim 3, wherein the inclined surface is inclined with respect to the axis of the gear in a direction opposite to a direction in which the tooth surface is inclined with respect to the axis of the gear, and intersects the tooth surface. .
円盤状のウエブと、前記ウエブの外周部に設けられたはすばの歯面を備えるはすば歯車としての歯車において、
前記ウエブの一面側から窪んだ複数の一面側凹部と、
前記ウエブの他面側から窪んだ複数の他面側凹部と、
前記歯車の半径方向に関して、前記ウエブの前記外周部よりも内側で前記複数の一面側凹部及び前記複数の他面側凹部よりも外側に配置された円環状の平面部を備え、前記円環状の平面部の前記歯車の軸線方向に関する厚みは、前記外周部の前記歯車の軸線方向に関する厚みよりも薄く、且つ、前記複数の一面側凹部及び前記複数の他面側凹部の前記歯車の軸線方向の幅よりも薄く、
前記一面側凹部と前記他面側凹部は前記歯車の円周方向に沿って交互に配置され、前記歯車の軸線方向において位置が重なり、
前記一面側凹部または前記他面側凹部の少なくとも一方の凹部は、前記一方の凹部の一部を形成し、前記歯車の軸線に対して傾斜する傾斜面を有し、
前記歯車の軸線に直交する方向から見て、前記傾斜面は前記歯車の軸線に対して、前記歯面が前記歯車の軸線に対して傾く向きとは反対側に傾き、前記歯面と交差することを特徴とする歯車。
In a gear as a helical gear provided with a disk-shaped web and a helical tooth surface provided on the outer peripheral portion of the web,
A plurality of one-side recesses recessed from one side of the web;
A plurality of recesses on the other surface side that are recessed from the other surface side of the web;
An annular plane portion disposed on the inner side of the outer peripheral portion of the web and on the outer side of the plurality of one-surface-side recesses and the plurality of other-surface-side recesses with respect to the radial direction of the gear , The thickness of the planar portion in the axial direction of the gear is thinner than the thickness of the outer peripheral portion in the axial direction of the gear, and the plurality of one-surface-side recesses and the plurality of other-surface-side recesses in the axial direction of the gears. Thinner than width,
The one-surface-side recesses and the other-surface-side recesses are alternately arranged along the circumferential direction of the gear, and the positions overlap in the axial direction of the gear,
At least one recess of the one-surface-side recess or the other-surface-side recess forms a part of the one recess, and has an inclined surface that is inclined with respect to the axis of the gear,
When viewed from the direction perpendicular to the axis of the gear, the inclined surface is inclined to the opposite side of the direction in which the tooth surface is inclined with respect to the axis of the gear and intersects the tooth surface. A gear characterized by that.
前記歯車の軸線に直交する方向から見て、前記歯面と前記傾斜面直交することを特徴とする請求項4又は5に記載の歯車。 The gear according to claim 4 , wherein the tooth surface and the inclined surface are orthogonal to each other when viewed from a direction orthogonal to the axis of the gear. 前記一面側凹部と前記他面側凹部の数は同数であることを特徴とする請求項1乃至のいずれか1項に記載の歯車。 The gear according to any one of claims 1 to 6 , wherein the number of the one-surface-side recesses and the other-surface-side recesses is the same. 前記歯車は熱可塑性樹脂で形成されることを特徴とする請求項1乃至のいずれか1項に記載の歯車。 Gear according to any one of claims 1 to 7 wherein the gear is characterized in that it is formed of a thermoplastic resin. 記録媒体に画像を形成する画像形成装置において、
静電潜像が形成される感光体ドラムと
請求項1乃至のいずれか1項に記載の歯車と、
を備えることを特徴とする画像形成装置。
In an image forming apparatus for forming an image on a recording medium,
A photosensitive drum on which an electrostatic latent image is formed; and the gear according to any one of claims 1 to 8 ,
An image forming apparatus comprising:
前記歯車は、前記感光体ドラムを回転させる駆動力を伝えるために用いられることを特徴とする請求項に記載の画像形成装置。 The image forming apparatus according to claim 9 , wherein the gear is used to transmit a driving force for rotating the photosensitive drum.
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