JP2009287647A - Worm supporting structure of steering assisting device - Google Patents

Worm supporting structure of steering assisting device Download PDF

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Publication number
JP2009287647A
JP2009287647A JP2008139795A JP2008139795A JP2009287647A JP 2009287647 A JP2009287647 A JP 2009287647A JP 2008139795 A JP2008139795 A JP 2008139795A JP 2008139795 A JP2008139795 A JP 2008139795A JP 2009287647 A JP2009287647 A JP 2009287647A
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bush
cylindrical surface
worm
bearing
outer peripheral
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JP5140494B2 (en
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Noboru Nakagawa
昇 中川
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Oiles Industry Co Ltd
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Oiles Industry Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C27/00—Elastic or yielding bearings or bearing supports, for exclusively rotary movement
    • F16C27/04—Ball or roller bearings, e.g. with resilient rolling bodies
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C35/00—Rigid support of bearing units; Housings, e.g. caps, covers
    • F16C35/04—Rigid support of bearing units; Housings, e.g. caps, covers in the case of ball or roller bearings
    • F16C35/06—Mounting or dismounting of ball or roller bearings; Fixing them onto shaft or in housing
    • F16C35/07—Fixing them on the shaft or housing with interposition of an element
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2361/00—Apparatus or articles in engineering in general
    • F16C2361/61—Toothed gear systems, e.g. support of pinion shafts

Abstract

<P>PROBLEM TO BE SOLVED: To provide a worm supporting structure of a steering assisting device which is advantageous in cost reduction while suppressing generation of tooth striking sound. <P>SOLUTION: Another side of a shaft section 1006 of a worm 10 is rotatably supported in a bushing attaching section 28 of a housing 14 through an inner bushing 22, a bearing 24, an outer bushing 26, and an urging member 32. The outer bushing 26 is made of a synthetic resin, and includes an outer periphery cylindrical surface 2602 and an inner circumference cylindrical surface 2604. The periphery cylindrical surface 2602 includes a first periphery cylindrical surface 2602A engaged with a cylindrical surface 2802 for attaching the bushing, and a second periphery cylindrical surface 2602B formed in a radius smaller than that of the first periphery cylindrical surface 2602A. The outer bushing 26 is incorporated within the cylindrical surface 2802 for attaching the bushing, and the bearing 24 is urged to a worm wheel 12 side by the urging member 32. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は自動車の操舵補助装置に関し、より詳細には操舵補助装置のウォーム支持構造に関する。   The present invention relates to a steering assist device for an automobile, and more particularly to a worm support structure for a steering assist device.

自動車の操舵補助装置として、例えば、電動パワーステアリング装置が従来から提供されている。
この種の電動パワーステアリング装置では、電動モータの出力をウォームおよびウォームホイールを介して減速して操舵機構に伝達し、ステアリング操作をトルクアシストするようにしている。
一方、ウォームとウォームホイールとの噛み合いにはバックラッシが必要となるが、走行時にこのバックラッシに起因した歯打ち音（ラトル音）が発生する。 As an automobile steering assist device, for example, an electric power steering device has been conventionally provided.
In this type of electric power steering apparatus, the output of the electric motor is decelerated via a worm and a worm wheel and transmitted to a steering mechanism to assist the steering operation with torque.
On the other hand, a backlash is required for meshing between the worm and the worm wheel, but a rattling sound (rattle sound) due to the backlash is generated during traveling.

そこで従来では、ウォームを回転可能支持するベアリングを、板ばねを介してハウジングで支持し、板ばねによりウォームをウォームホイール方向に付勢し、歯打ち音の発生を抑制するようにしている（特許文献１〜４参照）。
特開２００６−１７５８９１ 特許第３７８８５７６ 特許第３９５１９１３ 特開２００２−９６７４９ Therefore, conventionally, a bearing that rotatably supports the worm is supported by a housing via a leaf spring, and the worm is urged toward the worm wheel by the leaf spring to suppress generation of rattling noise (patent) References 1-4).
JP 2006-175891 Patent No. 3788576 Patent No. 39951913 JP2002-96749

しかしながら、このような構成では、ベアリングとして高い精度のものが必要となり、また、板ばねには特殊な材料を必要とするため、自動車の操舵補助装置のコストダウンを図る上で不利があった。
本発明はかかる事情に鑑み成されたものであり、本発明の目的は、歯打ち音の発生を抑制しつつコストダウンを図る上で有利な操舵補助装置のウォーム支持構造およびそれに用いるブッシュを提供することにある。 However, in such a configuration, a bearing with high accuracy is required, and a special material is required for the leaf spring, which is disadvantageous in reducing the cost of a steering assist device for an automobile.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a worm support structure for a steering assist device and a bush used therefor that are advantageous in reducing the cost while suppressing the occurrence of rattling noise. There is to do.

上記目的を達成するため、本発明は、ウォームホイールに噛合するウォームの両端の軸部がハウジング内に支持された操舵補助装置のウォーム支持構造において、前記両端の軸部のうちの一方の軸部は、前記ハウジングに形成されたブッシュ装着部に装着された第１のブッシュと、前記第１のブッシュと前記一方の軸部との間に介装されたベアリングとを介して支持され、前記第１のブッシュは合成樹脂材料で形成され、前記ブッシュ装着部は、ブッシュ装着用円筒面を有し、前記第１のブッシュは、外周円筒面と、前記ベアリングを支持する内周円筒面とを有し、前記外周円筒面と前記内周円筒面とは同芯的関係にあり、前記外周円筒面は、前記ブッシュ装着用円筒面に係合する第１外周円筒面と、前記第１外周円筒面よりも小さい半径で形成された第２外周円筒面とを有し、前記ブッシュ装着用円筒面内において、前記第１外周円筒面が前記ウォームホイールに接近離間する方向に移動可能に組み込まれ、前記第１のブッシュは、前記第２外周円筒面に形成された切り欠き部を有し、該切り欠き部が前記ウォームホイールとは反対側に向けられて前記第１のブッシュが前記ブッシュ装着用円筒面に組み込まれており、前記第１のブッシュの前記切り欠き部と前記ハウジングの前記ブッシュ装着用円筒面との間に介装した付勢部材によって前記ベアリングを前記ウォームホイールの側へ付勢していることを特徴とする。
また、本発明は、ウォームホイールに噛合するウォームの両端の軸部がハウジング内に支持された操舵補助装置のウォーム支持構造において、前記両端の軸部のうちの一方の軸部は、前記ハウジングに形成されたブッシュ装着部に装着された第１のブッシュと、前記第１のブッシュと前記一方の軸部との間に介装されたベアリングとを介して支持され、前記第１のブッシュは合成樹脂材料で形成され、前記ブッシュ装着部は、ブッシュ装着用円筒面を有し、前記第１のブッシュは、前記ブッシュ装着用円筒面に嵌合する外周円筒面と、内周面とを有し、前記内周面は、前記外周円筒面と同芯的関係にある内周円筒面と、前記内周円筒面の互いに対向する箇所に互いに平行する平面で設けられた平面部とを有し、前記ベアリングは、前記平面部が平行する方向に沿って移動可能に前記内周面内に配設され、前記第１のブッシュは、前記ベアリングの移動方向と、前記ウォームホイールに離間接近する方向とが一致するように前記ブッシュ装着用円筒面に組み込まれており、前記第１のブッシュの前記内周円筒面と前記ベアリングとの間に介装した付勢部材によって前記ベアリングを前記ウォームホイールの側へ付勢していることを特徴とする。 In order to achieve the above object, according to the present invention, there is provided a worm support structure for a steering assist device in which shaft portions at both ends of a worm meshing with a worm wheel are supported in a housing. Is supported via a first bush mounted on a bush mounting portion formed in the housing, and a bearing interposed between the first bush and the one shaft portion, 1 bush is formed of a synthetic resin material, the bush mounting portion has a bush mounting cylindrical surface, and the first bush has an outer peripheral cylindrical surface and an inner peripheral cylindrical surface supporting the bearing. The outer peripheral cylindrical surface and the inner peripheral cylindrical surface are in a concentric relationship, and the outer peripheral cylindrical surface includes a first outer peripheral cylindrical surface that engages with the bush mounting cylindrical surface, and the first outer peripheral cylindrical surface. With a smaller radius A second outer peripheral cylindrical surface formed, and the first outer peripheral cylindrical surface is incorporated in the bush mounting cylindrical surface so as to be movable toward and away from the worm wheel. And a cutout portion formed on the second outer peripheral cylindrical surface, the cutout portion being directed to the opposite side of the worm wheel, and the first bushing being incorporated into the bushing cylindrical surface. And the bearing is biased toward the worm wheel by a biasing member interposed between the notch of the first bush and the bush mounting cylindrical surface of the housing. And
Further, the present invention provides a worm support structure for a steering assist device in which shaft portions at both ends of a worm meshing with a worm wheel are supported in a housing, and one of the shaft portions at both ends is connected to the housing. The first bush is supported by a first bush mounted on the formed bush mounting portion and a bearing interposed between the first bush and the one shaft portion, and the first bush is synthesized. The bush mounting portion has a bush mounting cylindrical surface, and the first bush has an outer peripheral cylindrical surface that fits into the bush mounting cylindrical surface, and an inner peripheral surface. The inner peripheral surface has an inner peripheral cylindrical surface that is concentric with the outer peripheral cylindrical surface, and a plane portion provided by planes parallel to each other at mutually opposed locations on the inner peripheral cylindrical surface, The bearing has the flat surface portion. The first bush is mounted in the inner peripheral surface so as to be movable along a parallel direction, and the first bush is mounted so that a moving direction of the bearing coincides with a direction in which the worm wheel moves away from and approaches. The bearing is urged toward the worm wheel by an urging member interposed between the inner peripheral cylindrical surface of the first bush and the bearing. Features.

本発明の操舵補助装置のウォーム支持構造によれば、ウォームの一端を支持するベアリングとハウジングとの間に介装した第１のブッシュは、ベアリングとハウジングとの空間を充填するようにして装着されるため、ウォームの軸心をウォームホイールに対して相対的に移動させることに伴なう異音の発生が確実に防止される。
また、操舵補助装置の作動中にウォームホイールの歯面からウォームの歯面へ作用する衝撃力が付勢部材によって緩衝されるため、ウォームホイールの歯面とウォームの歯面との衝突による歯打ち音も小さく抑えられると共に、ウォームを支持するベアリングには、ウォームの軸方向に予圧が与えられているので、ベアリングのガタをなくし得、ガタに起因する異音の発生を防止することができる。
請求項１記載の発明によれば、第１のブッシュの切り欠き部とハウジングのブッシュ装着部との間に付勢部材を介装したことにより、ベアリングと付勢部材とを切り離し、ベアリングと付勢部材の振動による打音を吸収することができる。
また、請求項４記載の発明によれば、第１のブッシュの内周円筒面とベアリングとの間に付勢部材を介装したことにより、ベアリングと付勢部材の振動による打音を第１のブッシュ内で吸収することができる。 According to the worm support structure of the steering assist device of the present invention, the first bush interposed between the bearing supporting the one end of the worm and the housing is mounted so as to fill the space between the bearing and the housing. Therefore, the generation of noise due to the movement of the worm shaft relative to the worm wheel is reliably prevented.
Further, the impact force acting on the worm tooth surface from the worm wheel tooth surface during operation of the steering assist device is buffered by the urging member, so that the tooth strike caused by the collision between the worm wheel tooth surface and the worm tooth surface is avoided. The noise is suppressed to a small level, and the bearing that supports the worm is preloaded in the axial direction of the worm, so that the backlash of the bearing can be eliminated and the generation of abnormal noise due to the backlash can be prevented.
According to the first aspect of the present invention, since the biasing member is interposed between the notch portion of the first bush and the bush mounting portion of the housing, the bearing and the biasing member are separated, and the bearing and the bearing are attached. The hitting sound caused by the vibration of the biasing member can be absorbed.
According to the fourth aspect of the present invention, the urging member is interposed between the inner peripheral cylindrical surface of the first bush and the bearing, so that the first sound generated by the vibration of the bearing and the urging member is reduced. Can be absorbed in the bush.

以下に本発明の実施の形態について添付図面を参照しつつ説明する。
図１は第１の実施の形態の操舵補助装置の要部断面図、図２はモータの動力が入力される側のウォームの一端の支持構造の説明図、図３は本発明が適用されたウォームの支持構造の説明図、図４はアウターブッシュ、付勢部材の説明図、図５は付勢部材の側面図、図６は第１の実施の形態の変形例の要部断面図を示す。
図１に示すように、第１の実施の形態の自動車の操舵補助装置８である電動パワーステアリング装置では、操舵補助用のモータの動力が、ウォーム１０およびウォームホイール１２を介して減速され操舵機構に伝達される。
操舵補助装置８はウォーム１０を回転可能に支持するハウジング１４を有している。
ウォーム１０は、歯部１００２と、歯部１００２の両端の軸部１００４、１００６とを有している。
図２に示すように、モータの動力が入力される側の軸部１００４には、その外周面に第３のブッシュとしての合成樹脂製のインナーブッシュ１６が嵌合され、この軸部１００４は、インナーブッシュ１６の外周面に圧入嵌合されるとともにハウジング１４の軸受部２０に固定されたベアリング１８に回転可能に支持されている。
インナーブッシュ１６は、筒部１６０２と、筒部１６０２の一方の端部に半径方向外方に環状に拡がるように形成された鍔部１６０４とを有している。
鍔部１６０４は、インナーブッシュ１６が軸部１００４の外周面に嵌合された際、軸部１００４に設けられたフランジ１０１０に当接している。
ベアリング１８のインナレースはインナーブッシュ１６の筒部１６０２に嵌合され、ベアリング１８のアウタレースはハウジング１４の軸受部２０に嵌合されて配設されている。 Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a main part of the steering assist device according to the first embodiment, FIG. 2 is an explanatory view of a support structure of one end of a worm on the side where power of a motor is input, and FIG. FIG. 4 is an explanatory diagram of an outer bush and an urging member, FIG. 5 is a side view of the urging member, and FIG. 6 is a cross-sectional view of an essential part of a modification of the first embodiment. .
As shown in FIG. 1, in the electric power steering device that is the steering assist device 8 for an automobile according to the first embodiment, the power of the steering assist motor is decelerated via the worm 10 and the worm wheel 12 and the steering mechanism. Is transmitted to.
The steering assist device 8 includes a housing 14 that rotatably supports the worm 10.
The worm 10 includes a tooth portion 1002 and shaft portions 1004 and 1006 at both ends of the tooth portion 1002.
As shown in FIG. 2, a synthetic resin inner bush 16 serving as a third bush is fitted to the outer peripheral surface of the shaft portion 1004 on the side where the power of the motor is input. The inner bush 16 is press-fitted onto the outer peripheral surface and is rotatably supported by a bearing 18 fixed to the bearing portion 20 of the housing 14.
The inner bush 16 includes a cylindrical portion 1602 and a flange portion 1604 formed at one end portion of the cylindrical portion 1602 so as to expand annularly outward in the radial direction.
The flange portion 1604 is in contact with a flange 1010 provided on the shaft portion 1004 when the inner bush 16 is fitted to the outer peripheral surface of the shaft portion 1004.
The inner race of the bearing 18 is fitted to the cylindrical portion 1602 of the inner bush 16, and the outer race of the bearing 18 is fitted to the bearing portion 20 of the housing 14.

図３に示すように、ウォーム１０の他方の軸部１００６には、その外周面に嵌合固定された第２のブッシュとしての、例えば天然ゴム、合成ゴム、ポリウレタンゴム、アクリルゴム、ポリエステルエラストマーなどの弾性材料製のインナーブッシュ２２と、該インナーブッシュ２２の外周面に嵌合されたベアリング２４と、該ベアリング２４の外周面を囲繞してハウジング１４のブッシュ装着部２８に固定された第１のブッシュとしての、例えばポリアセタール樹脂、ポリアミド樹脂などの合成樹脂製のアウターブッシュ２６とが配されており、他方の軸部１００６は、該インナーブッシュ２２、ベアリング２４、アウターブッシュ２６、付勢部材３２を介してハウジング１４のブッシュ装着部２８で回転可能に支持されている。
インナーブッシュ２２は、筒部２２０２と該筒部２２０２の一方の端部に半径方向外方に環状に拡がるように形成された鍔部２２０４とを有しており、該鍔部２２０４は、該インナーブッシュ２２が軸部１００６の外周面に嵌合された際、軸部１００６に設けられたフランジ１０１２に当接して配されている。 As shown in FIG. 3, the other shaft portion 1006 of the worm 10 has, for example, natural rubber, synthetic rubber, polyurethane rubber, acrylic rubber, polyester elastomer or the like as a second bush fitted and fixed to the outer peripheral surface thereof. An inner bush 22 made of an elastic material, a bearing 24 fitted to the outer peripheral surface of the inner bush 22, and a first fixed to the bush mounting portion 28 of the housing 14 surrounding the outer peripheral surface of the bearing 24. An outer bush 26 made of a synthetic resin such as polyacetal resin or polyamide resin is disposed as a bush, and the other shaft portion 1006 includes the inner bush 22, the bearing 24, the outer bush 26, and the biasing member 32. Via the bush mounting portion 28 of the housing 14.
The inner bush 22 includes a cylindrical portion 2202 and a flange portion 2204 formed at one end portion of the cylindrical portion 2202 so as to expand radially outwardly, and the flange portion 2204 includes the inner bushing 22204. When the bush 22 is fitted to the outer peripheral surface of the shaft portion 1006, the bush 22 is disposed in contact with a flange 1012 provided on the shaft portion 1006.

なお、ウォーム１０がハウジング１４に組み付けられると、ウォーム１０の両端の軸部１００４及び１００６の外周面に夫々嵌合固定されたインナーブッシュ１６及び２２の鍔部１６０４及び２２０４は、それぞれウォーム１０の軸方向に締め代を有しているので、ベアリング１８及び２４に鍔部１６０４及び２２０４とフランジ１０１０及び１０１２との間で予圧を与えることができ、結果としてベアリング１８及び２４のガタをなくし得、ガタに起因する異音の発生を防止することができる。
なお、本実施の形態においては、インナーブッシュ１６の鍔部１６０４にウォーム１０の軸方向の締め代を有している例を説明したが、図６に示すように、筒部１６０２と鍔部１６０４を夫々別体にて形成し、鍔部１６０４にウェーブワッシャ（波座金）、スプリングワッシャ（ばね座金）、皿バネ等をバネ部材を使用することもできる。 When the worm 10 is assembled to the housing 14, the flange portions 1604 and 2204 of the inner bushes 16 and 22 fitted and fixed to the outer peripheral surfaces of the shaft portions 1004 and 1006 at both ends of the worm 10 are respectively connected to the shaft of the worm 10. Since there is a margin in the direction, the bearings 18 and 24 can be preloaded between the flanges 1604 and 2204 and the flanges 1010 and 1012. As a result, the play of the bearings 18 and 24 can be eliminated. It is possible to prevent the occurrence of abnormal noise due to the noise.
In the present embodiment, the example in which the flange portion 1604 of the inner bush 16 has the tightening allowance of the worm 10 in the axial direction has been described. However, as shown in FIG. 6, the cylindrical portion 1602 and the flange portion 1604 are provided. Can be formed separately, and a wave member such as a wave washer, a spring washer, a disc spring, or the like can be used for the collar portion 1604.

ブッシュ装着部２８は、ブッシュ装着用円筒面２８０２と、環状の端面２８０４とを有している。
ブッシュ装着用円筒面２８０２に、図３に示すように、半径方向外側に窪む凹部２８０６が設けられている。 The bush mounting portion 28 has a bush mounting cylindrical surface 2802 and an annular end surface 2804.
As shown in FIG. 3, the bush mounting cylindrical surface 2802 is provided with a recess 2806 that is recessed outward in the radial direction.

アウターブッシュ２６は、例えばポリアセタール樹脂、ポリアミド樹脂などの合成樹脂材料で形成されている。
図３、図４に示すように、アウターブッシュ２６は、外周円筒面２６０２と、ベアリング２４を支持する内周円筒面２６０４とを有し、外周円筒面２６０２と内周円筒面２６０４とは同芯的関係にある。
ベアリング２４のインナレースはインナーブッシュ２２の筒部２２０２に嵌合され、ベアリング２４のアウタレースがアウターブッシュ２６の内周円筒面２６０４に嵌合されて配設されている。
外周円筒面２６０２は、ブッシュ装着用円筒面２８０２に係合する第１外周円筒面２６０２Ａと、第１外周円筒面２６０２Ａよりも小さい半径で形成された第２外周円筒面２６０２Ｂとを有している。
第１外周円筒面２６０２Ａに、凹部２８０６に係合してアウターブッシュ２６の回転を阻止する凸部２６０３が設けられている。
第２外周円筒面２６０２Ｂに、切り欠き部３０が設けられている。
アウターブッシュ２６は、ブッシュ装着用円筒面２８０２内において、第１外周円筒面２６０２Ａがウォームホイール１２に接近離間する方向に移動可能に組み込まれている。
また、アウターブッシュ２６には、その厚さ方向の両端にそれぞれ端面が形成されると共に、軸部１００６の端部寄りに位置する端面側の内周円筒面２６０４の端部に、半径方向内側に突出しつつ周方向に延在する第１鍔部２６１０が設けられている。 The outer bush 26 is made of a synthetic resin material such as polyacetal resin or polyamide resin.
As shown in FIGS. 3 and 4, the outer bush 26 has an outer peripheral cylindrical surface 2602 and an inner peripheral cylindrical surface 2604 that supports the bearing 24, and the outer peripheral cylindrical surface 2602 and the inner peripheral cylindrical surface 2604 are concentric. In a relationship.
The inner race of the bearing 24 is fitted to the cylindrical portion 2202 of the inner bush 22, and the outer race of the bearing 24 is fitted to the inner peripheral cylindrical surface 2604 of the outer bush 26.
The outer peripheral cylindrical surface 2602 has a first outer peripheral cylindrical surface 2602A that engages with the bush mounting cylindrical surface 2802, and a second outer peripheral cylindrical surface 2602B formed with a smaller radius than the first outer peripheral cylindrical surface 2602A. .
A convex portion 2603 that engages with the concave portion 2806 and prevents the outer bush 26 from rotating is provided on the first outer peripheral cylindrical surface 2602A.
The notch 30 is provided in the second outer peripheral cylindrical surface 2602B.
The outer bush 26 is incorporated in the bush mounting cylindrical surface 2802 so that the first outer peripheral cylindrical surface 2602A can move in a direction approaching and separating from the worm wheel 12.
Further, the outer bush 26 is formed with end surfaces at both ends in the thickness direction, and radially inward in the end portion of the inner peripheral cylindrical surface 2604 on the end surface side located near the end portion of the shaft portion 1006. A first flange portion 2610 that extends in the circumferential direction while protruding is provided.

切り欠き部３０は、第２外周円筒面２６０２Ｂの一部を仮想平面で切断することで形成され、アウターブッシュ２６がブッシュ装着用円筒面２８０２に嵌合された際に、三日月状の空間がそれらアウターブッシュ２６とブッシュ装着用円筒面２８０２との間に形成されるように設けられている。この切り欠き部３０の底部３００２は細長い矩形状の平面部を成している。更に、底部３００２の４辺から起立し外周円筒面２６０２に繋がる側面部３００４が設けられ、底部３００２と側面部３００４とにより切り欠き部３０が形成されている。   The notch 30 is formed by cutting a part of the second outer peripheral cylindrical surface 2602B with a virtual plane, and when the outer bush 26 is fitted to the bush mounting cylindrical surface 2802, the crescent-shaped space is formed by these parts. It is provided so as to be formed between the outer bush 26 and the bush mounting cylindrical surface 2802. The bottom 3002 of the cutout 30 forms an elongated rectangular flat portion. Further, a side surface portion 3004 that stands up from four sides of the bottom portion 3002 and is connected to the outer peripheral cylindrical surface 2602 is provided, and the notch portion 30 is formed by the bottom portion 3002 and the side surface portion 3004.

切り欠き部３０には、付勢部材３２である板ばねが配設される。
すなわち、付勢部材３２である板ばねの第１部分３２０２が切り欠き部３０の底部３００２に当接し、切り欠き部３０に収容されて配設され、付勢部材３２の姿勢の安定化が図られている。
付勢部材３２は、板ばねに限られず、例えば、ゴムなどの弾性材料で形成することも可能である。
本実施の形態では、図５に示すように、板ばねにより付勢部材３２が構成され、この板ばねは、切り欠き部３０の底部３００２に当接する細長の平板状の第１部分３２０２と、この第１部分３２０２の長手方向の端部から屈曲部を介して連結され湾曲板状に延在してブッシュ装着用円筒面２８０２に当接する第２部分３２０４とを有している。 A leaf spring that is an urging member 32 is disposed in the notch 30.
That is, the first portion 3202 of the leaf spring as the biasing member 32 abuts on the bottom portion 3002 of the notch 30 and is accommodated in the notch 30 so that the posture of the biasing member 32 is stabilized. It has been.
The urging member 32 is not limited to a leaf spring, and may be formed of an elastic material such as rubber, for example.
In the present embodiment, as shown in FIG. 5, the urging member 32 is configured by a leaf spring, and the leaf spring includes an elongated flat plate-like first portion 3202 that abuts against the bottom portion 3002 of the cutout portion 30. The first portion 3202 has a second portion 3204 that is connected from a longitudinal end portion through a bent portion, extends in a curved plate shape, and abuts against the bush mounting cylindrical surface 2802.

そして、凸部２６０３が凹部２８０６に係合し、第１外周円筒面２６０２Ａがブッシュ装着用円筒面２８０２に係合し、切り欠き部３０がウォームホイール１２とは反対側に向けられ、アウターブッシュ２６が、ベアリング２４とハウジング１４との間の空間を充填するようにハウジング１４に装着される。これにより、アウターブッシュ２６の切り欠き部３０とブッシュ装着用円筒面２８０２との間に介装した付勢部材３２によってベアリング２４をウォームホイール１２の側へ付勢している。   Then, the convex portion 2603 is engaged with the concave portion 2806, the first outer peripheral cylindrical surface 2602A is engaged with the bush mounting cylindrical surface 2802, the notch portion 30 is directed to the side opposite to the worm wheel 12, and the outer bush 26 Is mounted on the housing 14 so as to fill a space between the bearing 24 and the housing 14. Accordingly, the bearing 24 is urged toward the worm wheel 12 by the urging member 32 interposed between the notch 30 of the outer bush 26 and the bush mounting cylindrical surface 2802.

本実施の形態によれば、次のような効果が奏される。
（１）ウォーム１０の一端を支持するベアリング２４とハウジング１４との間に介装した第１のブッシュとしてのアウターブッシュ２６は、ベアリング２４とハウジング１４との空間を充填するようにして装着されるため、ウォーム１０の軸心をウォームホイール１２に対して相対的に移動させることに伴なう異音の発生が確実に防止される。
また、操舵補助装置の作動中にウォームホイール１２の歯面からウォーム１０の歯面へ作用する衝撃力が付勢部材３２によって緩衝されるため、ウォームホイール１２の歯面とウォーム１０の歯面との衝突による歯打ち音も小さく抑えられると共に、ウォーム１０を支持するベアリング２４には、ウォーム１０の軸方向に予圧が与えられているので、ベアリング２４のガタをなくし得、ガタに起因する異音の発生を防止することができる。
（２）第１のブッシュとしてのアウターブッシュ２６の切り欠き部３０とハウジング１４のブッシュ装着部４８との間に付勢部材３２を介装したことにより、ベアリング２４と付勢部材３２とを切り離し、ベアリング２４と付勢部材３２の振動による打音を吸収することができる。
（３）このウォームの支持構造の寸法精度は主としてアウターブッシュ２６の寸法精度によって決まるが、アウターブッシュ２６の形状は簡明でしかも対称性の高いものであるため、高い寸法精度を有するアウターブッシュ２６を低コストで製造することができ、ひいては、高精度のウォーム支持構造を低コストで製造することが可能である。
（４）ウォーム１０を支持するベアリング１８及び２４には、ウォーム１０の軸方向に予圧が与えられているので、ベアリング１８及び２４のガタをなくし得、ガタに起因する異音の発生を防止することができる。 According to the present embodiment, the following effects are exhibited.
(1) An outer bush 26 serving as a first bush interposed between the bearing 24 supporting one end of the worm 10 and the housing 14 is mounted so as to fill a space between the bearing 24 and the housing 14. Therefore, the generation of noise accompanying the movement of the shaft center of the worm 10 relative to the worm wheel 12 is reliably prevented.
Further, since the impact force acting on the tooth surface of the worm 10 from the tooth surface of the worm wheel 12 during operation of the steering assist device is buffered by the biasing member 32, the tooth surface of the worm wheel 12, the tooth surface of the worm 10 and Since the bearing 24 that supports the worm 10 is preloaded in the axial direction of the worm 10, it is possible to eliminate the backlash of the bearing 24, and the abnormal noise caused by the backlash is reduced. Can be prevented.
(2) Since the biasing member 32 is interposed between the notch 30 of the outer bush 26 serving as the first bush and the bush mounting portion 48 of the housing 14, the bearing 24 and the biasing member 32 are separated. Further, it is possible to absorb a sound hit by vibration of the bearing 24 and the biasing member 32.
(3) Although the dimensional accuracy of the worm support structure is mainly determined by the dimensional accuracy of the outer bush 26, the shape of the outer bush 26 is simple and highly symmetric. It can be manufactured at a low cost, and thus a high-precision worm support structure can be manufactured at a low cost.
(4) Since preload is applied to the bearings 18 and 24 supporting the worm 10 in the axial direction of the worm 10, the backlash of the bearings 18 and 24 can be eliminated, and the generation of abnormal noise due to backlash can be prevented. be able to.

次に第２の実施の形態について説明する。
図７は第２の実施の形態の操舵補助装置の要部断面図、図８は第２の実施の形態のウォームの支持構造の説明図、図９（Ａ）はアウターブッシュの側面図、（Ｂ）は内周円筒面４６０４Ａと、平面部４６０４Ｂと、付勢部材５０との関係図、図１０は付勢部材の側面図、図１１は第２の実施の形態の変形例の要部断面図を示す。なお第１の実施の形態と同様な箇所、部材に同一の符号を付してその説明を省略する。
図７に示すように、第２の実施の形態の自動車の操舵補助装置８である電動パワーステアリング装置では、操舵補助用のモータの動力が、ウォーム１０およびウォームホイール１２を介して減速され操舵機構に伝達される。
操舵補助装置８はウォーム１０を回転可能に支持するハウジング１４を有している。
ウォーム１０は、歯部１００２と、歯部１００２の両端の軸部１００４、１００６とを有している。 Next, a second embodiment will be described.
FIG. 7 is a cross-sectional view of the main part of the steering assist device of the second embodiment, FIG. 8 is an explanatory view of the worm support structure of the second embodiment, FIG. 9A is a side view of the outer bush, B) is a diagram showing the relationship between the inner peripheral cylindrical surface 4604A, the flat surface portion 4604B, and the urging member 50, FIG. 10 is a side view of the urging member, and FIG. 11 is a cross-sectional view of the main part of a modification of the second embodiment. The figure is shown. In addition, the same code | symbol is attached | subjected to the location and member similar to 1st Embodiment, and the description is abbreviate | omitted.
As shown in FIG. 7, in the electric power steering device that is the steering assist device 8 of the automobile according to the second embodiment, the power of the steering assist motor is decelerated via the worm 10 and the worm wheel 12 and the steering mechanism. Is transmitted to.
The steering assist device 8 includes a housing 14 that rotatably supports the worm 10.
The worm 10 includes a tooth portion 1002 and shaft portions 1004 and 1006 at both ends of the tooth portion 1002.

モータの動力が入力される側の軸部１００４には、その外周面に第３のブッシュとしての合成樹脂製のインナーブッシュ４０が嵌合され、この軸部１００４は、インナーブッシュ４０の外周面に圧入嵌合されるとともにハウジング１４の軸受部２０に固定されたベアリング１８に回転可能に支持されている。
インナーブッシュ４０は、筒部４００２と、筒部４００２の一方の端部に半径方向外方に環状に拡がるように形成された鍔部４００４とを有している。
鍔部４００４は、インナーブッシュ４０が軸部１００４の外周面に嵌合された際、軸部１００４に設けられたフランジ１０１０に当接している。
ベアリング１８のインナレースはインナーブッシュ４０の筒部４００２に嵌合され、ベアリング１８のアウタレースはハウジング１４の軸受部２０に嵌合されて配設されている。 An inner bush 40 made of synthetic resin as a third bush is fitted to the outer peripheral surface of the shaft portion 1004 on the motor input side, and the shaft portion 1004 is formed on the outer peripheral surface of the inner bush 40. The bearing 18 is press-fitted and supported rotatably on a bearing 18 fixed to the bearing portion 20 of the housing 14.
The inner bush 40 includes a cylindrical portion 4002 and a flange portion 4004 formed at one end of the cylindrical portion 4002 so as to expand radially outward.
The flange portion 4004 abuts on a flange 1010 provided on the shaft portion 1004 when the inner bush 40 is fitted to the outer peripheral surface of the shaft portion 1004.
The inner race of the bearing 18 is fitted to the cylindrical portion 4002 of the inner bush 40, and the outer race of the bearing 18 is fitted to the bearing portion 20 of the housing 14.

図８に示すように、ウォーム１０の他方の軸部１００６には、その外周面に嵌合固定された第２のブッシュとしての、例えば例えば天然ゴム、合成ゴム、ポリウレタンゴム、アクリルゴム、ポリエステルエラストマーなどの弾性材料製のインナーブッシュ４２と、該インナーブッシュ４２の外周面に嵌合されたベアリング４４と、該ベアリング４４の外周面を囲繞してハウジング１４のブッシュ装着部４８に固定された第１のブッシュとしての、例えばポリアセタール樹脂、ポリアミド樹脂などの合成樹脂材料製のアウターブッシュ４６とが配されており、他方の軸部１００６は、該インナーブッシュ４２、ベアリング４４、アウターブッシュ４６、付勢部材５０を介してハウジング１４のブッシュ装着部４８で回転可能に支持されている。
インナーブッシュ４２は、筒部４２０２と該筒部４２０２の一方の端部に半径方向外方に環状に拡がるように形成された鍔部４２０４とを有しており、該鍔部４２０４は、該インナーブッシュ４２が軸部１００６の外周面に嵌合された際、軸部１００６に設けられた段部１０１２に当接して配されている。
なお、ウォーム１０がハウジング１４に組み付けられると、ウォーム１０の両端の軸部１００４及び１００６の外周面に夫々嵌合固定されたインナーブッシュ４０及び４２の鍔部４００４及び４２０４は、それぞれウォーム１０の軸方向に締め代を有しているので、ベアリング１８及び４４に鍔部４００４及び４２０４とフランジ１０１０及び段部１０１２との間で予圧を与えることができ、結果としてベアリング１８及び４４のガタをなくし得、ガタに起因する異音の発生を防止することができる。
なお、本実施の形態においては、インナーブッシュ４０の鍔部４００４にウォーム１０の軸方向の締め代を有している例を説明したが、図１１に示すように、筒部４００２と鍔部４００４を夫々別体にて形成し、鍔部１６０４にウェーブワッシャ（波座金）、スプリングワッシャ（ばね座金）、皿バネ等のバネ部材を使用することもできる。 As shown in FIG. 8, for example, natural rubber, synthetic rubber, polyurethane rubber, acrylic rubber, polyester elastomer as the second bush fitted and fixed to the outer peripheral surface of the other shaft portion 1006 of the worm 10. An inner bush 42 made of an elastic material such as, a bearing 44 fitted to the outer peripheral surface of the inner bush 42, and a first fixed to the bush mounting portion 48 of the housing 14 surrounding the outer peripheral surface of the bearing 44. The outer bush 46 made of a synthetic resin material such as polyacetal resin or polyamide resin is disposed, and the other shaft portion 1006 includes the inner bush 42, the bearing 44, the outer bush 46, and an urging member. A bush mounting portion 48 of the housing 14 is rotatably supported via 50.
The inner bush 42 includes a cylindrical portion 4202 and a flange portion 4204 formed at one end portion of the cylindrical portion 4202 so as to expand radially outward. The flange portion 4204 includes the inner bushing 424. When the bush 42 is fitted to the outer peripheral surface of the shaft portion 1006, the bush 42 is disposed in contact with a stepped portion 1012 provided on the shaft portion 1006.
When the worm 10 is assembled to the housing 14, the flanges 4004 and 4204 of the inner bushes 40 and 42 that are fitted and fixed to the outer peripheral surfaces of the shaft portions 1004 and 1006 at both ends of the worm 10 are respectively connected to the shaft of the worm 10. Since there is a margin in the direction, the bearings 18 and 44 can be preloaded between the flanges 4004 and 4204 and the flange 1010 and the stepped portion 1012. As a result, the play of the bearings 18 and 44 can be eliminated. , It is possible to prevent the occurrence of abnormal noise due to play.
In the present embodiment, the example in which the flange portion 4004 of the inner bush 40 has the axial allowance of the worm 10 has been described. However, as shown in FIG. 11, the cylindrical portion 4002 and the flange portion 4004. Can be formed separately, and a spring member such as a wave washer, a spring washer, or a disc spring can be used for the flange portion 1604.

第２の実施の形態では、ベアリング４４のインナレースはインナーブッシュ４２の筒部４２０２に嵌合され、ベアリング４４のアウタレースが付勢部材５０を介してアウターブッシュ４６に配設されている。より詳細には、アウターブッシュ４６とベアリング４４との間に付勢部材５０が介装され、この付勢部材５０によってベアリング４４をウォームホイール１２の側へ付勢している。   In the second embodiment, the inner race of the bearing 44 is fitted into the cylindrical portion 4202 of the inner bush 42, and the outer race of the bearing 44 is disposed on the outer bush 46 via the biasing member 50. More specifically, an urging member 50 is interposed between the outer bush 46 and the bearing 44, and the urging member 50 urges the bearing 44 toward the worm wheel 12.

アウターブッシュ４６は、例えばポリアセタール樹脂、ポリアミド樹脂などの合成樹脂材料で形成されている。
図８、図９に示すように、アウターブッシュ４６は、ブッシュ装着用円筒面４８０２に嵌合する外周円筒面４６０２と、内周面４６０４とを有している。
内周面４６０４は、外周円筒面４６０２と同芯的関係にある内周円筒面４６０４Ａと、内周円筒面４６０４Ａの互いに対向する箇所に互いに平行する平面で設けられた平面部４６０４Ｂとを有している。
内周円筒面４６０４Ａに凹部４６０６が形成されている。凹部４６０６は、ウォームホイール１２とは反対に位置するアウターブッシュ４６の内周円筒面４６０４の箇所に位置している。 The outer bush 46 is made of a synthetic resin material such as polyacetal resin or polyamide resin.
As shown in FIGS. 8 and 9, the outer bush 46 has an outer peripheral cylindrical surface 4602 that fits into the bush mounting cylindrical surface 4802 and an inner peripheral surface 4604.
The inner peripheral surface 4604 has an inner peripheral cylindrical surface 4604A that is concentric with the outer peripheral cylindrical surface 4602, and a flat surface portion 4604B that is provided in parallel to each other at locations facing each other on the inner peripheral cylindrical surface 4604A. ing.
A recess 4606 is formed in the inner peripheral cylindrical surface 4604A. The recess 4606 is located at a location on the inner peripheral cylindrical surface 4604 of the outer bush 46 positioned opposite to the worm wheel 12.

付勢部材５０は、例えば、ゴムや板ばねなどの弾性材料で構成することができるが、本実施の形態のように、板ばねにより構成することが特に好ましい。
付勢部材５０を構成している板ばねは、図９（Ｂ）に示すように、円筒面状に延在しベアリング４４のアウタレースの外周面に巻回され互いに対向する平面部４６０４Ｂの間に移動可能に挟持される第１部分５００２と、アウターブッシュ４６の凹部４６０６の底部に当接する第２部分５００４とを有している。
また、アウターブッシュ４６の厚さ方向の両端にそれぞれ端面が位置しており、軸部１００６の端部寄りに位置する端面側の内周円筒面４６０４の端部に、半径方向内側に突出しつつ周方向に延在する第１鍔部４６１０が設けられている。 The biasing member 50 can be made of an elastic material such as rubber or a leaf spring, for example, but is particularly preferably made of a leaf spring as in the present embodiment.
As shown in FIG. 9B, the leaf spring constituting the urging member 50 extends between the flat surface portions 4604B extending in a cylindrical surface and wound around the outer peripheral surface of the outer race of the bearing 44 and facing each other. It has the 1st part 5002 clamped so that a movement and the 2nd part 5004 contact | abutted to the bottom part of the recessed part 4606 of the outer bush 46 are included.
Further, end surfaces are located at both ends in the thickness direction of the outer bush 46, and the outer bush 46 protrudes radially inward at the end of the inner peripheral cylindrical surface 4604 on the end surface side located near the end of the shaft portion 1006. A first flange 4610 extending in the direction is provided.

第２の実施の形態では、ベアリング４４は、平面部４６０４Ｂが平行する方向に沿って移動可能に内周面４６０４に配設され、アウターブッシュ４６は、ベアリング４４の移動方向と、ウォームホイール１２に離間接近する方向とが一致するようにブッシュ装着用円筒面４８０２に組み込まれ、付勢部材５０によってベアリング４４をウォームホイール１２の側へ付勢している。   In the second embodiment, the bearing 44 is disposed on the inner peripheral surface 4604 so as to be movable along the direction in which the flat surface portion 4604B is parallel, and the outer bush 46 is disposed on the worm wheel 12 and the moving direction of the bearing 44. It is incorporated in the bush mounting cylindrical surface 4802 so as to coincide with the approaching distance, and the bearing 44 is urged toward the worm wheel 12 by the urging member 50.

本実施の形態によれば、次のような効果が奏される。
（１）ウォーム１０の一端を支持するベアリング４４とハウジング１４との間に介装した第１のブッシュとしてのアウターブッシュ４６は、ベアリング４４とハウジング１４との空間を充填するようにして装着されるため、ウォーム１０の軸心をウォームホイール１２に対して相対的に移動させることに伴なう異音の発生が確実に防止される。
また、操舵補助装置の作動中にウォームホイール１２の歯面からウォーム１０の歯面へ作用する衝撃力が付勢部材５０によって緩衝されるため、ウォームホイール１２の歯面とウォーム１０の歯面との衝突による歯打ち音も小さく抑えられると共に、ウォーム１０を支持するベアリング４４には、ウォーム１０の軸方向に予圧が与えられているので、ベアリング４４のガタをなくし得、ガタに起因する異音の発生を防止することができる。
（２）アウターブッシュ４６の内周面４６０４とベアリング４４との間に付勢部材５０を介装したことにより、ベアリング４４と付勢部材５０の振動による打音をアウターブッシュ４６内で吸収することができる。
（３）ウォーム１０を支持するベアリング１８及び４４には、ウォーム１０の軸方向に予圧が与えられているので、ベアリング１８及び４４のガタをなくし得、ガタに起因する異音の発生を防止することができる。 According to the present embodiment, the following effects are exhibited.
(1) The outer bush 46 as a first bush interposed between the bearing 44 that supports one end of the worm 10 and the housing 14 is mounted so as to fill the space between the bearing 44 and the housing 14. Therefore, the generation of noise accompanying the movement of the shaft center of the worm 10 relative to the worm wheel 12 is reliably prevented.
Further, since the impact force acting on the tooth surface of the worm 10 from the tooth surface of the worm wheel 12 during operation of the steering assist device is buffered by the biasing member 50, the tooth surface of the worm wheel 12, the tooth surface of the worm 10 and The bearing 44 that supports the worm 10 is also preloaded in the axial direction of the worm 10, so that the backlash of the bearing 44 can be eliminated, and the abnormal noise caused by the play is reduced. Can be prevented.
(2) The urging member 50 is interposed between the inner peripheral surface 4604 of the outer bush 46 and the bearing 44, so that the impact sound caused by the vibration of the bearing 44 and the urging member 50 is absorbed in the outer bush 46. Can do.
(3) Since preload is applied to the bearings 18 and 44 supporting the worm 10 in the axial direction of the worm 10, the backlash of the bearings 18 and 44 can be eliminated, and the generation of abnormal noise due to backlash can be prevented. be able to.

以上に説明したように、本実施の形態に係る操舵補助装置８のウォーム支持構造によれば、ウォーム１０とウォームホイール１２との間の芯間調整の機能を有し、低コストでウォーム支持構造を製造することが可能となり、そのウォーム支持構造は、高度の異音発生防止性能を有するものとなり、コストダウンを図りつつ歯打ち音（ラトル音）の発生を抑制することが可能となる。   As described above, according to the worm support structure of the steering assist device 8 according to the present embodiment, the worm support structure has a function of adjusting the center between the worm 10 and the worm wheel 12 and is low in cost. The worm support structure has a high level of noise generation prevention capability, and can suppress the generation of rattling noise (rattle noise) while reducing costs.

第１の実施の形態の操舵補助装置の要部断面図である。It is principal part sectional drawing of the steering assistance apparatus of 1st Embodiment. モータの動力が入力される側のウォームの一端の支持構造の説明図である。It is explanatory drawing of the support structure of the end of the worm | warm at the side into which the motive power of a motor is input. 本発明が適用されたウォームの支持構造の説明図である。It is explanatory drawing of the support structure of the worm to which this invention was applied. アウターブッシュ、付勢部材の説明図である。It is explanatory drawing of an outer bush and a biasing member. 付勢部材の側面図である。It is a side view of a biasing member. 第１の実施の形態の変形例の要部断面図である。It is principal part sectional drawing of the modification of 1st Embodiment. 第２の実施の形態の操舵補助装置の要部断面図である。It is principal part sectional drawing of the steering auxiliary device of 2nd Embodiment. 第２の実施の形態のウォームの支持構造の説明図である。It is explanatory drawing of the support structure of the worm | warm of 2nd Embodiment. （Ａ）はアウターブッシュの側面図、（Ｂ）は内周円筒面４６０４Ａと、平面部４６０４Ｂと、付勢部材５０との関係図である。(A) is a side view of the outer bush, and (B) is a relationship diagram of the inner peripheral cylindrical surface 4604A, the flat surface portion 4604B, and the urging member 50. 付勢部材の側面図である。It is a side view of a biasing member. 第２の実施の形態の変形例の要部断面図である。It is principal part sectional drawing of the modification of 2nd Embodiment.

符号の説明Explanation of symbols

８……操舵補助装置、１０……ウォーム、１００４、１００６……軸部、１２……ウォームホイール、１４……ハウジング、１６、２２、４０、４２……インナーブッシュ、１８、２４、４４……ベアリング、２２……インナーブッシュ、２６、４６……アウターブッシュ、２８、４８……ブッシュ装着部、３０……切り欠き部、３２、５０……付勢部材。   8 ... Steering assist device, 10 ... Worm, 1004, 1006 ... Shaft, 12 ... Worm wheel, 14 ... Housing, 16, 22, 40, 42 ... Inner bush, 18, 24, 44 ... Bearings, 22 ... inner bush, 26, 46 ... outer bush, 28, 48 ... bush mounting portion, 30 ... notch, 32, 50 ... biasing member.

Claims (9)

ウォームホイールに噛合するウォームの両端の軸部がハウジング内に支持された操舵補助装置のウォーム支持構造において、
前記両端の軸部のうちの一方の軸部は、前記ハウジングに形成されたブッシュ装着部に装着された第１のブッシュと、前記第１のブッシュと前記一方の軸部との間に介装されたベアリングとを介して支持され、
前記第１のブッシュは合成樹脂材料で形成され、
前記ブッシュ装着部は、ブッシュ装着用円筒面を有し、
前記第１のブッシュは、外周円筒面と、前記ベアリングを支持する内周円筒面とを有し、前記外周円筒面と前記内周円筒面とは同芯的関係にあり、
前記外周円筒面は、前記ブッシュ装着用円筒面に係合する第１外周円筒面と、前記第１外周円筒面よりも小さい半径で形成された第２外周円筒面とを有し、前記ブッシュ装着用円筒面内において、前記第１外周円筒面が前記ウォームホイールに接近離間する方向に移動可能に組み込まれ、
前記第１のブッシュは、前記第２外周円筒面に形成された切り欠き部を有し、該切り欠き部が前記ウォームホイールとは反対側に向けられて前記第１のブッシュが前記ブッシュ装着用円筒面に組み込まれており、
前記第１のブッシュの前記切り欠き部と前記ハウジングの前記ブッシュ装着用円筒面との間に介装した付勢部材によって前記ベアリングを前記ウォームホイールの側へ付勢している、
ことを特徴とする操舵補助装置のウォーム支持構造。 In the worm support structure of the steering assist device in which the shaft portions at both ends of the worm meshing with the worm wheel are supported in the housing,
One shaft portion of the shaft portions at both ends is interposed between a first bush mounted on a bush mounting portion formed on the housing, and between the first bush and the one shaft portion. Supported through bearings,
The first bush is formed of a synthetic resin material,
The bush mounting portion has a bush mounting cylindrical surface,
The first bush has an outer peripheral cylindrical surface and an inner peripheral cylindrical surface that supports the bearing, and the outer peripheral cylindrical surface and the inner peripheral cylindrical surface are in a concentric relationship,
The outer peripheral cylindrical surface has a first outer peripheral cylindrical surface engaged with the bush mounting cylindrical surface, and a second outer peripheral cylindrical surface formed with a smaller radius than the first outer peripheral cylindrical surface, and the bush mounting In the cylindrical surface for use, the first outer peripheral cylindrical surface is incorporated so as to be movable toward and away from the worm wheel,
The first bush has a notch formed in the second outer peripheral cylindrical surface, and the notch is directed to the opposite side of the worm wheel so that the first bush is for mounting the bush. Built into the cylindrical surface,
The bearing is biased toward the worm wheel by a biasing member interposed between the notch portion of the first bush and the bush mounting cylindrical surface of the housing.
A worm support structure for a steering assist device. 前記付勢部材は板ばねで構成されていることを特徴とする請求項１記載の操舵補助装置のウォーム支持構造。   The worm support structure for a steering assist device according to claim 1, wherein the urging member includes a leaf spring. 前記板ばねは、前記第１のブッシュの前記切り欠き部の底部に当接する第１部分と、前記ハウジングの前記ブッシュ装着用円筒面に当接する第２部分とを有する、
ことを特徴とする請求項２記載の操舵補助装置のウォーム支持構造。 The leaf spring includes a first portion that contacts the bottom of the notch of the first bush, and a second portion that contacts the bush mounting cylindrical surface of the housing.
The worm support structure for a steering assist device according to claim 2. ウォームホイールに噛合するウォームの両端の軸部がハウジング内に支持された操舵補助装置のウォーム支持構造において、
前記両端の軸部のうちの一方の軸部は、前記ハウジングに形成されたブッシュ装着部に装着された第１のブッシュと、前記第１のブッシュと前記一方の軸部との間に介装されたベアリングとを介して支持され、
前記第１のブッシュは合成樹脂材料で形成され、
前記ブッシュ装着部は、ブッシュ装着用円筒面を有し、
前記第１のブッシュは、前記ブッシュ装着用円筒面に嵌合する外周円筒面と、内周面とを有し、
前記内周面は、前記外周円筒面と同芯的関係にある内周円筒面と、前記内周円筒面の互いに対向する箇所に互いに平行する平面で設けられた平面部とを有し、
前記ベアリングは、前記平面部が平行する方向に沿って移動可能に前記内周面内に配設され、
前記第１のブッシュは、前記ベアリングの移動方向と、前記ウォームホイールに離間接近する方向とが一致するように前記ブッシュ装着用円筒面に組み込まれており、
前記第１のブッシュの前記内周円筒面と前記ベアリングとの間に介装した付勢部材によって前記ベアリングを前記ウォームホイールの側へ付勢している、
ことを特徴とする操舵補助装置のウォーム支持構造。 In the worm support structure of the steering assist device in which the shaft portions at both ends of the worm meshing with the worm wheel are supported in the housing,
One shaft portion of the shaft portions at both ends is interposed between a first bush mounted on a bush mounting portion formed on the housing, and between the first bush and the one shaft portion. Supported through bearings,
The first bush is formed of a synthetic resin material,
The bush mounting portion has a bush mounting cylindrical surface,
The first bush has an outer peripheral cylindrical surface that fits into the bush mounting cylindrical surface, and an inner peripheral surface,
The inner peripheral surface has an inner peripheral cylindrical surface that is concentric with the outer peripheral cylindrical surface, and a plane portion provided in a plane parallel to each other at mutually opposed locations of the inner peripheral cylindrical surface,
The bearing is disposed in the inner peripheral surface so as to be movable along a direction in which the flat portion is parallel,
The first bush is incorporated in the bush mounting cylindrical surface so that the moving direction of the bearing and the direction of approaching and separating from the worm wheel coincide with each other.
The bearing is biased toward the worm wheel by a biasing member interposed between the inner peripheral cylindrical surface of the first bush and the bearing.
A worm support structure for a steering assist device. 前記付勢部材は板ばねで構成されていることを特徴とする請求項４記載の操舵補助装置のウォーム支持構造。   5. The worm support structure for a steering assist device according to claim 4, wherein the urging member comprises a leaf spring. 前記第１のブッシュの前記内周円筒面の一部に凹部が形成され、
前記板ばねは、円筒面状に延在し前記ベアリングの外周面に巻回され前記互いに対向する平面部の間に移動可能に挟持される第１部分と、前記第１のブッシュの前記凹部の底部に当接する第２部分とを有する、
ことを特徴とする請求項５記載の操舵補助装置のウォーム支持構造。 A recess is formed in a part of the inner peripheral cylindrical surface of the first bush,
The leaf spring extends in a cylindrical surface, is wound around the outer peripheral surface of the bearing, and is movably sandwiched between the planar portions facing each other, and the recess of the first bush. A second portion that abuts the bottom,
The worm support structure for a steering assist device according to claim 5. 前記ウォームは、前記両端の軸部の間に歯部を有し、
前記ウォームの両端の軸部にそれぞれ第２のブッシュと第３のブッシュとが嵌合され、
前記第２のブッシュは前記ベアリングにより支持されており、
前記第３のブッシュは前記ベアリングとは別のベアリングにより支持されており、
前記第２のブッシュと前記第３のブッシュの前記歯部寄りの箇所に半径方向外方に環状に拡がる鍔部が形成され、
前記ウォームの組み付け時に前記第２のブッシュの前記鍔部および前記第３のブッシュの前記鍔部は、前記ハウジングと前記ベアリングを介して前記ウォームの軸方向に締め付けられている、
ことを特徴とする請求項１乃至６に何れか１項記載の操舵補助装置のウォーム支持構造。 The worm has a tooth portion between the shaft portions at both ends,
A second bush and a third bush are respectively fitted to the shaft portions at both ends of the worm,
The second bush is supported by the bearing;
The third bush is supported by a bearing different from the bearing,
A flange portion that is annularly extended radially outward is formed at a location near the tooth portion of the second bush and the third bush,
When the worm is assembled, the flange portion of the second bush and the flange portion of the third bush are tightened in the axial direction of the worm via the housing and the bearing,
The worm support structure for a steering assist device according to any one of claims 1 to 6. 前記ウォームは、前記両端の軸部の間に歯部を有し、
前記ウォームの両端の軸部にそれぞれ第２のブッシュと第３のブッシュとが嵌合され、
前記第２のブッシュは前記ベアリングにより支持されており、
前記第３のブッシュは前記ベアリングとは別のベアリングにより支持されており、
前記第２のブッシュの前記歯部寄りの箇所に半径方向外方に環状に拡がる鍔部が形成され、
前記第３のブッシュは筒状を呈し、前記第３のブッシュの前記歯部寄りの箇所に、前記第３のブッシュの半径方向外側で環状に拡がる前記第３のブッシュとは別の部材で構成された環板状のばね部材が配置され、
前記ウォームの組み付け時に前記第２のブッシュの前記鍔部および前記ばね部材は、前記ハウジングと前記ベアリングを介して前記ウォームの軸方向に締め付けられている、
ことを特徴とする請求項１乃至５に何れか１項記載の操舵補助装置のウォーム支持構造。 The worm has a tooth portion between the shaft portions at both ends,
A second bush and a third bush are respectively fitted to the shaft portions at both ends of the worm,
The second bush is supported by the bearing;
The third bush is supported by a bearing different from the bearing,
A flange portion that is annularly expanded radially outward is formed at a location near the tooth portion of the second bush,
The third bush has a cylindrical shape, and is formed of a member different from the third bush that extends in an annular shape on the outer side in the radial direction of the third bush at a location near the tooth portion of the third bush. An annular plate-shaped spring member arranged,
When the worm is assembled, the flange portion and the spring member of the second bush are tightened in the axial direction of the worm via the housing and the bearing.
A worm support structure for a steering assist device according to any one of claims 1 to 5. 前記ブッシュ装着部の前記ブッシュ装着用円筒面に、半径方向外側に窪む凹部が設けられ、
前記第１のブッシュの前記外周円筒面に、前記凹部に係合して前記第１のブッシュの回転を阻止する凸部が設けられている、
請求項１乃至８に何れか１項記載の操舵補助装置のウォーム支持構造。 A concave portion that is recessed outward in the radial direction is provided on the bush mounting cylindrical surface of the bush mounting portion,
A convex portion that engages with the concave portion and prevents the rotation of the first bush is provided on the outer peripheral cylindrical surface of the first bush.
The worm support structure for a steering assist device according to any one of claims 1 to 8.
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WO2013161845A1 (en) 2012-04-25 2013-10-31 株式会社ジェイテクト Electric power steering device
JP2013226898A (en) * 2012-04-25 2013-11-07 Jtekt Corp Electric power steering device
US9638307B2 (en) 2012-04-25 2017-05-02 Jtekt Corporation Electric power steering device
JP2013237399A (en) * 2012-05-16 2013-11-28 Jtekt Corp Electric power steering device
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KR102254485B1 (en) 2014-09-25 2021-05-21 현대모비스 주식회사 Bearing bush
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CN109963770A (en) * 2016-11-24 2019-07-02 罗伯特·博世有限公司 Steering gear and steering system
JP2019536686A (en) * 2016-11-24 2019-12-19 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツングＲｏｂｅｒｔ Ｂｏｓｃｈ Ｇｍｂｈ Steering transmission and steering system
JPWO2021241135A1 (en) * 2020-05-27 2021-12-02
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