JP2552746B2 - Four-wheel steering system - Google Patents

Description

【発明の詳細な説明】 （産業上の利用分野） 本発明は、機械的伝達装置を介して前輪操舵取り装置
と後輪舵取り装置を連動して、後輪を前輪の操舵角に応
じて操舵するようにした四輪操舵装置に関する。The present invention relates to steering a rear wheel according to a steering angle of a front wheel by interlocking a front wheel steering device and a rear wheel steering device via a mechanical transmission device. The present invention relates to a four wheel steering device.

（従来の技術） この種の四輪操舵装置においては、前後の舵取り装置
を連動する伝達装置として回転軸や操作ケーブルを使用
している。(Prior Art) In this type of four-wheel steering device, a rotating shaft and an operation cable are used as a transmission device that links front and rear steering devices.

（発明が解決しようとする課題） このような従来技術においては、例えば後輪が溝に脱
輪などしてその操舵が阻止された場合に、操舵ハンドル
に力をこめて回そうとすると、伝達装置に無理な力が加
わって破損させたりする問題がある。特に操作ケーブル
を使用したものの場合は、操作ケーブルが伸びるなどし
て破損するおそれが大きい。(Problems to be Solved by the Invention) In such a conventional technique, for example, when the rear wheel is disengaged from the groove or the like and the steering is prevented, if the driver tries to turn the steering wheel with force, the transmission is performed. There is a problem that the device is damaged due to excessive force. In particular, in the case of using an operation cable, there is a high possibility that the operation cable may be damaged due to stretching or the like.

このような問題を解決するために、前後の舵取り装置
のハウジング内に、第６図に示すようなアシスト遅れ回
避機構を組み込むことが考えられる。このアシスト遅れ
回避機構は、前輪の操舵と連動して回転する入力回転部
材２と後輪を操舵する出力回転部材３を軸受6a,6bによ
りハウジング１内に支持し、この両回転部材2,3の間の
伝達トルクが所定値以上となれば相対回動するようにこ
の両部材を渦巻ばね５により連結したもので、アシスト
遅れ回避機構の外径を小さくするために渦巻ばね５を２
つに分けてハウジング１内に軸承した中間回転部材４に
より連結している。In order to solve such a problem, it is conceivable to incorporate an assist delay avoidance mechanism as shown in FIG. 6 into the housings of the front and rear steering devices. This assist delay avoidance mechanism supports an input rotary member 2 that rotates in conjunction with steering of the front wheels and an output rotary member 3 that steers the rear wheels in the housing 1 by means of bearings 6a and 6b. The two members are connected by a spiral spring 5 so as to rotate relative to each other when the transmission torque between the spiral springs becomes a predetermined value or more. In order to reduce the outer diameter of the assist delay avoidance mechanism, the spiral spring 5 is
They are divided into two parts and are connected by an intermediate rotating member 4 which is supported in the housing 1.

しかしながら第６図の構造のものは、中間回転部材４
の外周に軸受７を挟み込むような形をとっているため、
２つの部分4A,4Bを４本のボルト4Cで連結する必要があ
り、このため部品点数が多くなり、また一方の部分4A
は、第７図に示すように、各渦巻ばね５の内端が係合す
る係合ボス9a,9bの一部を接離可能に当接する面4bを形
成するために複雑な形状の切欠き4aを必要とし、このた
め加工費も大となる。また、中間回転部材４の外周をハ
ウジング１に支持させており、これに使用する軸受７が
大径となるので、部品価額が上昇すると共に余分のスペ
ースを必要とする。However, the structure of FIG.
Since the bearing 7 is sandwiched around the outer circumference of
It is necessary to connect the two parts 4A and 4B with four bolts 4C, which increases the number of parts, and also the one part 4A
As shown in FIG. 7, a notch having a complicated shape for forming a surface 4b that abuts a part of the engaging bosses 9a, 9b with which the inner ends of the spiral springs 5 engage so that they can come into contact with and separate from each other. 4a is required, which results in high processing cost. Further, since the outer periphery of the intermediate rotating member 4 is supported by the housing 1 and the bearing 7 used for this has a large diameter, the component price increases and an extra space is required.

本発明は、このような各問題を解決して、部品点数が
少なく、部品コストが少なく加工及び組立が容易で、し
かもコンパクトに構成することができるアシスト遅れ回
避機構を備えた四輪操舵装置を提供することを目的とす
る。The present invention solves each of the above problems, and provides a four-wheel steering system including an assist delay avoidance mechanism which has a small number of parts, a small part cost, is easy to machine and assemble, and can be configured compactly. The purpose is to provide.

（課題を解決するための手段） このために、本発明による四輪操舵装置は、第１図〜
第５図に例示するごとく、前輪を操舵する前輪舵取り装
置10と、後輪を操舵する後輪舵取り装置20と、この両舵
取り装置を連動する伝達装置よりなる四輪操舵装置にお
いて、ハウジング21に回動可能に支持され前輪の操舵と
連動して回転する入力回転部材41と、この入力回路部材
と同軸的にかつ軸方向に間をおいて前記ハウジング21に
軸承されて後輪を操舵する出力回転部材43と、この入力
及び出力回転部材41,43の内周側に軸受52,53を介してそ
れぞれ同軸的に回転自在に支持された第１及び第２係合
部材46,47と、前記入力及び出力回転部材41,43の間にそ
れぞれと軸方向に隙間をおいてかつ同軸的に配置され前
記第１及び第２係合部材46,47の何れか一方により内周
側が軸受54を介して回転自在に支持された単一部材の中
間回転部材42と、前記入力回転部材41と中間回転部材42
の間に設けられた第１渦巻ばね44及び前記中間回転部材
42と出力回転部材43の間に設けられた第２渦巻ばね45と
よりなるアシスト遅れ回避機構40を備えたことを特徴と
するものである。(Means for Solving the Problems) For this purpose, the four-wheel steering system according to the present invention is provided with the following arrangements:
As illustrated in FIG. 5, in a four-wheel steering device including a front wheel steering device 10 for steering front wheels, a rear wheel steering device 20 for steering rear wheels, and a transmission device for interlocking both steering devices, An input rotating member 41 which is rotatably supported and rotates in conjunction with steering of the front wheels, and an output which is supported by the housing 21 and is coaxially and axially spaced from the input circuit member to steer the rear wheels. A rotating member 43, first and second engaging members 46, 47 rotatably supported coaxially on the inner peripheral side of the input and output rotating members 41, 43 via bearings 52, 53, respectively. The input and output rotary members 41, 43 are axially spaced from each other and coaxially arranged, and one of the first and second engaging members 46, 47 has an inner peripheral side through a bearing 54. And a single member intermediate rotating member 42 rotatably supported by the input rotating unit. 41 and the intermediate rotary member 42
First spiral spring 44 and the intermediate rotating member provided between
The assist delay avoidance mechanism 40 including a second spiral spring 45 provided between the output rotation member 42 and the output rotation member 43 is provided.

（作用） 通常の作動状態においては、前後の舵取り装置10,20
間の伝達トルクは両渦巻ばね44,45の初期トルクよりも
小さいのでアシスト遅れ回避機構40は作動せず、入力回
転部材41の回転はそのまま出力回転部材43に伝達され、
後輪舵取り装置20は前輪の操舵に連動して正常に作動す
る。溝への脱輪などにより後輪の操舵が阻止された状態
において操舵ハンドルを無理に回すと前後の舵取り装置
10,20間の伝達トルクは増大する。しかしながらこの伝
達トルクが第１及び第２渦巻ばね44,45の初期トルクを
越えれば、この両渦巻ばね44,45が撓んでアシスト遅れ
回避機構40が作動するので伝達トルクの増大は防止さ
れ、前後の舵取り装置10,20間の伝達装置に無理な力が
加わることはなくなる。(Operation) In the normal operation state, the front and rear steering devices 10, 20
Since the transmission torque between the two spiral springs 44 and 45 is smaller than the initial torque, the assist delay avoidance mechanism 40 does not operate, and the rotation of the input rotary member 41 is transmitted to the output rotary member 43 as it is,
The rear wheel steering device 20 operates normally in conjunction with the steering of the front wheels. If the steering wheel is forcibly turned in a state where the rear wheels are prevented from being turned into the groove, etc., the front and rear steering devices
The transmission torque between 10 and 20 increases. However, if this transmission torque exceeds the initial torque of the first and second spiral springs 44, 45, both spiral springs 44, 45 will bend and the assist delay avoidance mechanism 40 will operate, preventing an increase in the transmission torque. Unnecessary force is not applied to the transmission device between the steering devices 10 and 20 of FIG.

中間回転部材42は内周側が軸受54を介して第１または
第２係合部材46,47により支持されているので、アシス
ト遅れ回避機構40の第１及び第２渦巻ばね44,45より外
側への突出量は少なくなる。Since the inner peripheral side of the intermediate rotation member 42 is supported by the first or second engagement member 46, 47 via the bearing 54, the intermediate rotation member 42 is positioned outside the first and second spiral springs 44, 45 of the assist delay avoidance mechanism 40. The amount of protrusion of is reduced.

（発明の効果） 上述のごとく、本発明によれば、前後の舵取り装置の
間の伝達装置に無理な力が加わって破損したりする恐れ
がなくなり、またアシスト遅れ回避機構の外径が渦巻ば
ねを１個だけ用いたものに比較して小となる。また本発
明では、中間回転部材を支持する軸受を内周側としたの
でアシスト遅れ回避機構の全体外径が一層小となり、こ
の軸受も安価となる。更に中間回転部材は単一部材であ
るので加工及び組立コストも少なくなる。従って、部品
コストが少なく、加工及び組立が容易で、しかもコンパ
クトに構成することができるアシスト遅れ回避機構を備
えた四輪操舵装置を得ることができる。(Effects of the Invention) As described above, according to the present invention, the transmission device between the front and rear steering devices is prevented from being damaged due to an unreasonable force, and the outer diameter of the assist delay avoidance mechanism is a spiral spring. It is smaller than that using only one. Further, in the present invention, since the bearing supporting the intermediate rotating member is on the inner peripheral side, the entire outer diameter of the assist delay avoiding mechanism is further reduced, and this bearing is also inexpensive. Further, since the intermediate rotating member is a single member, processing and assembling costs are reduced. Therefore, it is possible to obtain a four-wheel steering system having an assist delay avoiding mechanism which has a low component cost, is easy to process and assemble, and can be configured compactly.

（実施例） 以下に、第１図〜第５図に示す実施例により、本発明
の説明をする。(Example) Hereinafter, the present invention will be described with reference to examples shown in Figs. 1 to 5.

先ず第５図により、四輪操舵装置の全体構造の説明を
すれば、自動車のエンジン73により駆動される供給ポン
プ70によりリザーバ72から吸入されて送り出された所定
量の作動流体は、分流弁71により所定比率で分流され
て、その一方は前輪舵取り装置10に供給され、他方は後
輪舵取り装置20に供給され、使用後の作動流体はリザー
バ72に戻される。First, referring to FIG. 5, the overall structure of the four-wheel steering system will be described. The predetermined amount of working fluid sucked and delivered from the reservoir 72 by the supply pump 70 driven by the engine 73 of the automobile is divided by the flow dividing valve 71. The flow is divided at a predetermined ratio, one of which is supplied to the front wheel steering device 10 and the other of which is supplied to the rear wheel steering device 20, and the used working fluid is returned to the reservoir 72.

前輪動力舵取り装置10は、操舵ハンドル15の回転を前
輪作動ロッド13の往復動に変換するラックピニオン機構
12に伝達するハンドル軸16の途中に設けたロータリータ
イプの前輪サーボ弁11と前輪作動ロッド13に設けた前輪
パワーシリンダ14を主要な構成部材としている。前輪サ
ーボ弁11は操舵ハンドル15から入力されたハンドルトル
クに応じて作動し、分流弁71を介して供給ポンプ70から
前輪パワーシリンダ14の左右の作動室に供給される作動
流体の給排を制御し、これにより増幅された操舵力が前
輪作動ロッド13に出力され、その両端に設けたタイロッ
ド17及びナックルアーム18を介して左右の前輪19を操舵
するようになっている。The front wheel power steering device 10 is a rack and pinion mechanism that converts the rotation of the steering wheel 15 into reciprocating motion of the front wheel operating rod 13.
The main components are a rotary-type front wheel servo valve 11 provided in the middle of a handle shaft 16 for transmitting to the wheel shaft 12 and a front wheel power cylinder 14 provided on a front wheel operating rod 13. The front wheel servo valve 11 operates according to the steering wheel torque input from the steering wheel 15, and controls the supply and discharge of the working fluid supplied from the supply pump 70 to the left and right working chambers of the front wheel power cylinder 14 via the shunt valve 71. Then, the steering force amplified by this is output to the front wheel operating rod 13, and the left and right front wheels 19 are steered via tie rods 17 and knuckle arms 18 provided at both ends thereof.

後輪動力舵取り装置20は、第１図及び第５図に示すご
とく、ロータリータイプの後輪サーボ弁60と後輪パワー
シリンダ24を備え、更に操舵特性付与機構30及びアシス
ト遅れ回避機構40を備えている。後輪パワーシリンダ24
のピストン26に固定された後輪作動ロッド23はシリンダ
25の両端部から液密にかつ摺動自在に突出し、その両端
はタイロッド27及びナックルアーム28を介して後輪29に
連結されている。As shown in FIGS. 1 and 5, the rear wheel power steering device 20 includes a rotary type rear wheel servo valve 60 and a rear wheel power cylinder 24, and further includes a steering characteristic imparting mechanism 30 and an assist delay avoiding mechanism 40. ing. Rear wheel power cylinder 24
The rear wheel operating rod 23 fixed to the piston 26 of the
Liquid-tight and slidably project from both ends of 25, and both ends thereof are connected to a rear wheel 29 via a tie rod 27 and a knuckle arm 28.

第１図及び第４図に示すごとく、操舵特性付与機構30
は、互いに偏心した回転軸線O1,O2回りにそれぞれ回転
自在にハウジング21内に支持された入力軸31及び従動回
転部材34を備えており、入力軸31に略Ｖ字状に形成され
た案内溝32には、従動回転部材34に設けた従動子33が係
合されている。従動子33は、回転軸線O2から偏心して従
動回転部材34に固定された支持ピン33aの前部に回転自
在に支持されたローラ33bよりなり、支持ピン33aの後端
は従動回転部材34より後方に突出している。As shown in FIGS. 1 and 4, the steering characteristic imparting mechanism 30
Includes an input shaft 31 and a driven rotating member 34, which are rotatably supported in the housing 21 about eccentric rotation axes O1 and O2, respectively, and a guide groove formed in the input shaft 31 in a substantially V shape. A follower 33 provided on a driven rotation member 34 is engaged with 32. The follower 33 comprises a roller 33b rotatably supported on the front part of a support pin 33a eccentric from the rotation axis O2 and fixed to the driven rotation member 34, and the rear end of the support pin 33a is rearward of the driven rotation member 34. Overhangs.

前後輪の操舵中立状態においては、従動子33のローラ
33bは第４図に示す状態にある。操舵中立状態から入力
軸31が回転すれば、入力軸31に対する従動回転部材34の
回転角の特性は次のようになる。すなわちローラ33bが
案内溝32の外側面に当接するまでは従動回転部材34は回
転せず、その後は入力軸31の回転角が増大するにつれて
従動回転部材34の回転角の増大の割合は次第に増大す
る。In the steering neutral state of the front and rear wheels, the roller of the follower 33 is
33b is in the state shown in FIG. When the input shaft 31 rotates from the steering neutral state, the characteristics of the rotation angle of the driven rotary member 34 with respect to the input shaft 31 are as follows. That is, the driven rotary member 34 does not rotate until the roller 33b contacts the outer surface of the guide groove 32, and thereafter, the rate of increase in the rotational angle of the driven rotary member 34 gradually increases as the rotational angle of the input shaft 31 increases. To do.

第５図に示すごとく、中間部にケーブル長さ調整装置
36を設けた一対の操作ケーブル35a,35bにより前後の動
力舵取り装置10,20を連動する伝達装置が構成されてい
る。各操作ケーブル35a,35bはインナワイヤ及びアウタ
チューブよりなり、各インナワイヤの一端は前輪作動ロ
ッド13の両端部に設けた突起にそれぞれ連結され、各イ
ンナワイヤの他端は入力軸31に形成したプーリ31aに巻
き付けられている。また、各アウタチューブの両端はそ
れぞれ前輪動力舵取り装置10のハウジング（図示省略）
及びハウジング21に取り付けられている。これにより前
輪作動ロッド13の往復動に応じて入力軸31が回動され
る。As shown in Fig. 5, a cable length adjusting device is provided in the middle part.
A pair of operation cables 35a, 35b provided with 36 constitutes a transmission device for interlocking the front and rear power steering devices 10, 20. Each operation cable 35a, 35b is composed of an inner wire and an outer tube, one end of each inner wire is connected to a protrusion provided on both ends of the front wheel operating rod 13, and the other end of each inner wire is connected to a pulley 31a formed on the input shaft 31. It is wrapped around. Both ends of each outer tube are housings of the front wheel power steering device 10 (not shown).
And attached to the housing 21. As a result, the input shaft 31 is rotated according to the reciprocating movement of the front wheel operating rod 13.

後輪サーボ弁60は、主として第１図に示すごとく、後
述するアシスト遅れ回避機構40を間において操舵特性付
与機構30の従動回転部材34と同軸的にハウジング21内に
設けられている。後輪サーボ弁60はトーションバー66に
より弾性的に連結された出力軸61と作動軸62を有し、出
力軸61の後部に形成したピニオン22は後輪作動ロッド23
に形成したラック23aと噛合している。作動軸62の先端
にセレーション結合されて抜け止め固定されたヨーク68
は、後述するアシスト遅れ回避機構40を介して従動回転
部材32と同軸的に連結されている。The rear wheel servo valve 60 is provided in the housing 21 coaxially with the driven rotary member 34 of the steering characteristic imparting mechanism 30 with an assist delay avoiding mechanism 40, which will be described later, in between, as mainly shown in FIG. The rear wheel servo valve 60 has an output shaft 61 and an operating shaft 62 that are elastically connected by a torsion bar 66, and the pinion 22 formed at the rear of the output shaft 61 is a rear wheel operating rod 23.
It meshes with the rack 23a formed on the. A yoke 68 that is serration-coupled to the tip of the actuating shaft 62 to prevent it from coming off.
Is coaxially connected to the driven rotation member 32 via an assist delay avoidance mechanism 40 described later.

後輪サーボ弁60の要部は作動軸62の一部に形成された
ロータ弁部材63と、ピン65により出力軸61に連結された
スリーブ弁部材64よりなる通常のロータリー形のサーボ
弁である。この後輪サーボ弁60は作動軸62に加わる入力
トルクに応じて作動し、入力ポート60aに供給された作
動流体の後輪パワーシリンダ24に対する給排を、２つの
分配ポート60c,60dを介して制御し、使用後の作動流体
を排出ポート60bを経てリザーバ72に排出して、後輪29
への操舵アシスト力を生ずるようになっている。The main part of the rear wheel servo valve 60 is a normal rotary type servo valve including a rotor valve member 63 formed on a part of an operating shaft 62 and a sleeve valve member 64 connected to an output shaft 61 by a pin 65. . The rear wheel servo valve 60 operates according to the input torque applied to the operating shaft 62, and the supply / discharge of the working fluid supplied to the input port 60a to / from the rear wheel power cylinder 24 is performed via the two distribution ports 60c and 60d. The working fluid after control is discharged to the reservoir 72 through the discharge port 60b, and the rear wheel 29
A steering assist force is generated.

アシスト遅れ回避機構40は、第１図に示すごとく、従
動回転部材34と同軸的に一体形成された入力回転部材41
及びこれと同軸的に軸方向に間をおいて配置された環状
の出力回転部材43を有し、この両回転部材41,43の外周
は間にカラー27をおいてハウジング21内面に嵌合された
大径の軸受50,51により支持されている。各回転部材41,
43の内周には小径の軸受52,53を介して第１及び第２係
合ボス（第１及び第２係合部材）46,47が同軸的に支持
され、この第２係合ボス47には両回転部材41,43の間に
それぞれ軸方向に隙間をおいて同軸的に配置された中間
回転部材42の内周が小径の軸受54を介して支持されてい
る。各第１及び第２係合ボス46,47には、それぞれ各回
転部材41,42及び42,43の間に位置する渦巻ばね44,45が
巻回して設けられている。３個の回転部材41,42,43は何
れも単一部材である。As shown in FIG. 1, the assist delay avoidance mechanism 40 includes an input rotation member 41 which is integrally formed coaxially with the driven rotation member 34.
And an annular output rotary member 43 arranged coaxially with this and spaced apart in the axial direction. The outer circumferences of the rotary members 41 and 43 are fitted to the inner surface of the housing 21 with a collar 27 therebetween. It is supported by large-diameter bearings 50 and 51. Each rotating member 41,
First and second engagement bosses (first and second engagement members) 46 and 47 are coaxially supported on the inner circumference of the shaft 43 through small-diameter bearings 52 and 53. The inner circumference of the intermediate rotary member 42, which is coaxially arranged with a gap in the axial direction between the rotary members 41 and 43, is supported by the bearing 54 having a small diameter. The first and second engaging bosses 46, 47 are provided with spiral springs 44, 45 wound between the rotating members 41, 42 and 42, 43, respectively. All of the three rotating members 41, 42, 43 are single members.

第１図〜第３図に示すごとく、互いに対向する入力回
転部材41及び中間回転部材42の外周部の一部には、互い
に接近する軸線方向に突出してそれぞれの先端が多少の
隙間をおいて互いに対向する第１係合ピン41b及び第２
係合ピン42bが、圧入等により固定されている。また互
いに対向する中間回転部材42及び出力回転部材43の外周
部の一部にも、同様の第３係合ピン42c及び第４係合ピ
ン43aがそれぞれ固定されている。中間回転部材42の内
周部の一部には内側係合ピン42aが軸線方向両側に突出
して固定され、また出力回転部材43の内周部の一部にも
第５係合ピン43bが軸線方向両側に突出して固定されて
いる。第１係合ボス46の前後面には支持ピン33a及び内
側係合ピン42aとそれぞれ係合可能な第１及び第２突起4
6a及び46bが形成され、また第２係合ボス47の前後端に
は内側係合ピン42a及び第５係合ピン43bとそれぞれ係合
可能な第３及び第４突起47a及び47bが形成されている。As shown in FIGS. 1 to 3, a part of the outer peripheral portions of the input rotary member 41 and the intermediate rotary member 42 facing each other project in the axial direction approaching each other and each tip has a slight gap. The first engagement pin 41b and the second that face each other
The engagement pin 42b is fixed by press fitting or the like. Further, similar third engaging pins 42c and fourth engaging pins 43a are fixed to a part of the outer peripheral portions of the intermediate rotating member 42 and the output rotating member 43 facing each other. The inner engagement pin 42a is fixed to a part of the inner peripheral portion of the intermediate rotating member 42 so as to project to both sides in the axial direction, and the fifth engagement pin 43b is also attached to a part of the inner peripheral portion of the output rotating member 43 along the axis. It is fixed by protruding to both sides in the direction. The front and rear surfaces of the first engagement boss 46 include first and second protrusions 4 which are engageable with the support pin 33a and the inner engagement pin 42a, respectively.
6a and 46b are formed, and the front and rear ends of the second engagement boss 47 are provided with third and fourth protrusions 47a and 47b which are respectively engageable with the inner engagement pin 42a and the fifth engagement pin 43b. There is.

第１渦巻ばね44はばね網等の帯板を渦巻状に巻回して
なり、入力及び中間回転部材41,42の間にトルクが加わ
っていない状態において、初期トルクが与えられてその
両端がそれぞれ両回転部材41,42の一部に同時に係合し
ている。すなわち、第１図及び第２図に示すごとく、第
１渦巻ばね44の折曲された外端44aは入力回転部材41の
第１係合ピン41b及び中間回転部材42の第２係合ピン42b
に逆時計回転方向から同時に係合している。また、第１
渦巻ばね44の折曲された内端44bは第１係合ボス46の第
２突起46bに時計回転方向から係合すると共に、この第
２突起46b及び第１突起46aは、それぞれ同時に中間回転
部材42の内側係合ピン42aの前端及び入力回転部材41の
支持ピン33aの後端に時計回転方向から係合している。The first spiral spring 44 is formed by spirally winding a strip plate such as a spring net, and in a state where no torque is applied between the input and intermediate rotating members 41, 42, initial torque is applied to both ends thereof. It is engaged with a part of both rotary members 41, 42 at the same time. That is, as shown in FIGS. 1 and 2, the bent outer end 44a of the first spiral spring 44 has the first engaging pin 41b of the input rotating member 41 and the second engaging pin 42b of the intermediate rotating member 42.
Are simultaneously engaged in the counterclockwise direction. Also, the first
The bent inner end 44b of the spiral spring 44 engages with the second protrusion 46b of the first engagement boss 46 in the clockwise direction, and the second protrusion 46b and the first protrusion 46a are simultaneously rotated by the intermediate rotation member. The front end of the inner engagement pin 42a of 42 and the rear end of the support pin 33a of the input rotation member 41 are engaged in the clockwise direction.

同様に、第１図及び第３図に示すごとく、中間及び出
力回転部材42,43の間にトルクが加わっていない状態に
おいて、初期トルクが与えられた第２渦巻ばね45は、外
端45aが中間回転部材42の第３係合ピン42c及び出力回転
部材43の第４係合ピン43aに逆時計回転方向から同時に
係合し、また内端45bは第２係合ボス47前後の第３及び
第４突起47a,47bを介して中間回転部材42の内側係合ピ
ン42aの後端及び出力回転部材43の第５係合ピン43bの前
端に時計回転方向から同時に係合している。第１及び第
２渦巻ばね45,46の素材及び諸元は初期トルクを含め互
いに同一である。Similarly, as shown in FIGS. 1 and 3, in the state where no torque is applied between the intermediate and output rotating members 42, 43, the second spiral spring 45 to which the initial torque is applied has the outer end 45a. The third engagement pin 42c of the intermediate rotation member 42 and the fourth engagement pin 43a of the output rotation member 43 are simultaneously engaged in the counterclockwise rotation direction, and the inner end 45b is provided with the third engagement pin 42a before and after the second engagement boss 47. The rear end of the inner engagement pin 42a of the intermediate rotation member 42 and the front end of the fifth engagement pin 43b of the output rotation member 43 are simultaneously engaged in the clockwise direction via the fourth protrusions 47a and 47b. The materials and specifications of the first and second spiral springs 45 and 46 are the same, including the initial torque.

このアシスト遅れ回避機構40は、両回転部材41,43の
間の伝達トルクが各渦巻ばね44,45の初期トルク以下の
場合は入力回転部材41の回動をそのまま出力回転部材43
に伝達するが、伝達トルクがそれ以上になれば各渦巻ば
ね44,45が撓んで入力回転部材41の回動が出力回転部材4
3に伝達されなくなるようにするものである。前記後輪
サーボ弁60の作動軸62先端に固定したヨーク68は、半径
方向に形成した切欠き68aが出力回転部材43の第５係合
ピン43bの後端に係合されて、アシスト遅れ回避機構40
に連結されている。When the transmission torque between the two rotating members 41 and 43 is equal to or less than the initial torque of the spiral springs 44 and 45, the assist delay avoiding mechanism 40 keeps the rotation of the input rotating member 41 as it is
However, when the transmitted torque becomes higher than that, the spiral springs 44 and 45 are bent and the rotation of the input rotary member 41 is rotated.
3 so that it is not transmitted. The yoke 68 fixed to the tip of the operation shaft 62 of the rear wheel servo valve 60 has a notch 68a formed in the radial direction engaged with the rear end of the fifth engagement pin 43b of the output rotary member 43 to avoid assist delay. Mechanism 40
It is connected to.

次に上記実施例の作動の説明をする。 Next, the operation of the above embodiment will be described.

操舵ハンドル15を中立位置から第５図の矢印に示すご
とく右回りに回動すれば、前輪動力舵取り装置10は前述
のごとく作動し、前輪作動ロッド13は矢印のごとく右向
きに移動して左右の前輪19を右向きに操舵する。これに
より操舵特性付与機構30の入力軸31は、操作ケーブル35
a,35bを介して、後から見て逆時計回転方向に回動され
る。また反対に、操舵ハンドル15を左回りに回動すれ
ば、各部分は上記と逆向きに作動して前輪19は左向きに
操舵され、入力軸31は後から見て時計回転方向に回動さ
れる。この入力軸31の回動に応じて従動回転部材32は前
述した特性で回動する。When the steering wheel 15 is rotated clockwise from the neutral position as shown by the arrow in FIG. 5, the front wheel power steering device 10 operates as described above, and the front wheel operating rod 13 moves rightward as shown by the arrow to move to the left or right. Steer the front wheels 19 to the right. As a result, the input shaft 31 of the steering characteristic imparting mechanism 30 is connected to the operation cable 35.
Via a, 35b, it is rotated in the counterclockwise rotation direction when viewed from behind. Conversely, if the steering handle 15 is turned counterclockwise, each part operates in the opposite direction to the above, the front wheel 19 is steered leftward, and the input shaft 31 is turned clockwise as viewed from behind. You. In response to the rotation of the input shaft 31, the driven rotary member 32 rotates with the characteristics described above.

正常な状態においては、後輪操舵トルクは小さいので
アシスト遅れ回避機構40は作動せず、従動回転部材32の
回動はそのままヨーク68から作動軸62に伝達されて後輪
サーボ弁60を作動させる。前輪19を右向きに操舵すれ
ば、入力軸31並びに後輪サーボ弁60の作動軸62及び出力
軸61は後から見て逆時計回転方向に回動し、後輪29は後
輪作動ロッド23を介して左向きに操舵される。この際、
後輪操舵トルクに応じて後輪サーボ弁60が作動し、後輪
パワーシリンダ24により後輪作動ロッド23にアシスト力
を与える。前輪19を左向きに操舵すれば、各部分は上記
と逆向きに作動して後輪29は右向きに操舵される。すな
わち、後輪29は前輪19の操舵に応じて逆相に操舵され
る。In a normal state, since the rear wheel steering torque is small, the assist delay avoidance mechanism 40 does not operate, and the rotation of the driven rotation member 32 is transmitted from the yoke 68 to the operation shaft 62 as it is to operate the rear wheel servo valve 60. . When the front wheels 19 are steered to the right, the input shaft 31, the operating shaft 62 and the output shaft 61 of the rear-wheel servo valve 60 rotate counterclockwise when viewed from the rear, and the rear wheels 29 move the rear-wheel operating rod 23. It is steered to the left via. On this occasion,
The rear-wheel servo valve 60 operates according to the rear-wheel steering torque, and the rear-wheel power cylinder 24 applies an assist force to the rear-wheel operating rod 23. If the front wheel 19 is steered to the left, each part operates in the opposite direction to the above, and the rear wheel 29 is steered to the right. That is, the rear wheels 29 are steered in reverse phase according to the steering of the front wheels 19.

後輪29が溝に落輪するなどして操舵が阻止された状態
で、操舵ハンドル15に力を込めて回せば、出力軸61と作
動軸62の間に設けたマニアルストッパ59をすぐに当接し
て、アシスト遅れ回避機構40に加わる伝達トルクは増大
しようとする。しかしながらこの伝達トルクが第１及び
第２渦巻ばね44,45の初期トルクよりも大となれば各渦
巻ばね44,45が撓むので入力回転部材41の回動は出力回
転部材43に伝達されなくなり、伝達トルクの増大は防止
される。If the steering wheel 15 is turned with force while the steering is blocked by the rear wheel 29 falling into the groove, etc., the manual stopper 59 provided between the output shaft 61 and the operating shaft 62 will immediately contact. Then, the transmission torque applied to the assist delay avoidance mechanism 40 tries to increase. However, if this transmission torque is larger than the initial torque of the first and second spiral springs 44 and 45, the spiral springs 44 and 45 will bend and the rotation of the input rotary member 41 will not be transmitted to the output rotary member 43. , Transmission torque is prevented from increasing.

この際の各渦巻ばね44,45の撓みはその両端部の各隣
接する回転部材41及び42または42及び43へ同時に係合し
ている箇所の一方が離れることにより行われる。例えば
第２図及び第３図において、入力回転部材41から出力回
転部材43への伝達トルクが時計回転方向の場合には、第
１渦巻ばね44は第１係合ピン41bにより外端44aが時計回
りに回され、内側係合ピン42aにより内端44bの回動に抵
抗が与えられることにより撓み、第２渦巻ばね45は第３
係合ピン42cにより外端45aが時計回りに回され、第５係
合ピン43bにより内端45bの回動が阻止されることにより
撓む。この場合には、支持ピン33aと第１突起46a、外端
44aと第２係合ピン42b、内側係合ピン42aと第３突起47
a、外端45aと第４係合ピン43aの間に隙間が生じる。入
力回転部材41から出力回転部材43への伝達トルクが逆時
計回転方向の場合には上記と逆の作動がなされ、第１係
合ピン41bと外端44a、第２突起46bと内側係合ピン42a、
第３係合ピン42cと外端45a、第４突起47bと第５係合ピ
ン43bの間に隙間が生じるように第１及び第２渦巻ばね4
4,45は撓む。この様な作用により伝達トルクの増大が防
止され、各操作ケーブル35a,35bに無理な力が加わって
破損を生ずるなどの恐れはなくなる。At this time, the spiral springs 44 and 45 are bent by one of the two ends of the spiral springs 44 and 45 being simultaneously engaged with the adjacent rotating members 41 and 42 or 42 and 43, respectively. For example, in FIG. 2 and FIG. 3, when the torque transmitted from the input rotary member 41 to the output rotary member 43 is clockwise, the first spiral spring 44 has the outer end 44a of which the time is adjusted by the first engaging pin 41b. The second spiral spring 45 is rotated around, and is bent by the resistance of the inner end 44b being turned by the inner engagement pin 42a.
The outer end 45a is rotated clockwise by the engagement pin 42c, and the inner end 45b is bent by the fifth engagement pin 43b so as to bend. In this case, the support pin 33a, the first protrusion 46a, the outer end
44a and second engagement pin 42b, inner engagement pin 42a and third protrusion 47
a, a gap is formed between the outer end 45a and the fourth engagement pin 43a. When the torque transmitted from the input rotary member 41 to the output rotary member 43 is in the counterclockwise direction, the operation reverse to the above is performed, and the first engagement pin 41b and the outer end 44a, the second protrusion 46b and the inner engagement pin. 42a,
The first and second spiral springs 4 are arranged so that a gap is created between the third engagement pin 42c and the outer end 45a and between the fourth protrusion 47b and the fifth engagement pin 43b.
4,45 bends. Due to such an action, increase of the transmission torque is prevented, and there is no fear that the operation cables 35a and 35b are damaged due to excessive force.

また上記実施例では、入力回転部材41と出力回転部材
43の間に中間回転部材42を設けて渦巻ばねを第１及び第
２渦巻ばね44,45の２つに分割しているので各渦巻ばね4
4,45の外径は１つの渦巻ばねのみを使用した場合に比し
て小となる。中間回転部材42は内周側が小径の軸受54を
介して第２係合ボス47により支持されているので、アシ
スト遅れ回避機構40が両渦巻ばね44,45より外側へ突出
することも少なくなり、ハウジング21内にコンパクトに
組み込むことができ、また軸受54も安価となり、カラー
27も１個で足りる。更に中間回転部材42は単一部材であ
ると共に内側係合ピン42aにより第１及び第２係合ボス4
6,47と係合させているので、複雑な切欠き（第７図の4a
参照）は不要となり、加工及び組立コストは少なくな
る。Further, in the above embodiment, the input rotary member 41 and the output rotary member
Since the intermediate rotating member 42 is provided between the spiral springs 43, the spiral spring is divided into the first spiral spring 44 and the second spiral spring 45.
The outer diameter of 4,45 is smaller than that when only one spiral spring is used. Since the inner peripheral side of the intermediate rotating member 42 is supported by the second engaging boss 47 via the bearing 54 having a small diameter, the assist delay avoiding mechanism 40 is less likely to project outward than the spiral springs 44, 45. It can be installed compactly in the housing 21, and the bearing 54 is also inexpensive,
One 27 is enough. Further, the intermediate rotation member 42 is a single member, and the first and second engagement bosses 4 are formed by the inner engagement pins 42a.
Since it is engaged with 6,47, it has a complicated notch (4a in Fig. 7).
(See) is unnecessary and processing and assembly costs are reduced.

本発明は、アシスト遅れ回避機構40を上記実施例のご
とく後輪動力舵取り装置20のハウジング21に設ける代わ
りに、前輪動力舵取り装置10のハウジングに設けて実施
することもできる。また、動力舵取り装置を使用しない
四輪操舵装置に適用することもできる。The present invention can be implemented by providing the assist delay avoiding mechanism 40 in the housing of the front wheel power steering device 10 instead of providing the assist delay avoiding mechanism 40 in the housing 21 of the rear wheel power steering device 20 as in the above embodiment. Further, the present invention can be applied to a four-wheel steering device that does not use a power steering device.

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

第１図〜第５図は本発明による四輪操舵装置の一実施例
を示し、第１図は要部の縦断面図、第２図は第１図のII
−II断面図、第３図は第１図のIII−III断面図、第４図
は第１図のIV−IV断面図、第５図は全体の概略平面図で
ある。第６図及び第７図は改良前の状態を示し、第６図
は要部の縦断面図、第７図は中間回転部材の一部の正面
図である。 符号の説明 10……前輪舵取り装置、20……後輪舵取り装置、21……
ハウジング、40……アシスト遅れ回避機構、41……入力
回転部材、42……中間回転部材、43……出力回転部材、
44……第１渦巻ばね、45……第２渦巻ばね、46……第１
係合部材（第１係合ボス）、47……第２係合部材（第２
係合ボス）、52,53,54……軸受。1 to 5 show an embodiment of a four-wheel steering system according to the present invention. FIG. 1 is a longitudinal sectional view of an essential part, and FIG. 2 is II of FIG.
-II sectional view, FIG. 3 is a III-III sectional view of FIG. 1, FIG. 4 is a IV-IV sectional view of FIG. 1, and FIG. 5 is an overall schematic plan view. 6 and 7 show a state before improvement, FIG. 6 is a longitudinal sectional view of a main part, and FIG. 7 is a front view of a part of the intermediate rotating member. Explanation of reference numerals 10 …… Front wheel steering device, 20 …… Rear wheel steering device, 21 ……
Housing, 40 ... Assist delay avoidance mechanism, 41 ... Input rotary member, 42 ... Intermediate rotary member, 43 ... Output rotary member,
44 …… first spiral spring, 45 …… second spiral spring, 46 …… first
Engaging member (first engaging boss), 47 ... Second engaging member (second
Engaging bosses), 52, 53, 54 ... Bearings.

───────────────────────────────────────────────────── フロントページの続き (72)発明者 小田 享 愛知県豊田市トヨタ町１番地 トヨタ自 動車株式会社内 (72)発明者 宮城 淳一 愛知県豊田市トヨタ町１番地 トヨタ自 動車株式会社内 (56)参考文献 特開 昭62−155169（ＪＰ，Ａ) 実開 昭62−155065（ＪＰ，Ｕ) ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kyo Oda 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Co., Ltd. (72) Inventor Junichi Miyagi, 1 Toyota Town, Aichi Prefecture, Toyota Motor Co., Ltd. ( 56) References Japanese Unexamined Patent Publication No. 62-155169 (JP, A) Actually developed 62-155065 (JP, U)

Claims (1)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】前輪を操舵する前輪舵取り装置と、後輪を
操舵する後輪舵取り装置と、この両舵取り装置を連動す
る伝達装置よりなる四輪操舵装置において、 ハウジングに回動可能に支持され前輪の操舵と連動して
回転する入力回転部材と、この入力回転部材と同軸的に
かつ軸方向に間をおいて前記ハウジング内に軸承されて
後輪を操舵する出力回転部材と、この入力及び出力回転
部材の内周側に軸受を介してそれぞれ同軸的に回転自在
に支持された第１及び第２係合部材と、前記入力及び出
力回転部材の間にそれぞれと軸方向に隙間をおいてかつ
同軸的に配置され前記第１及び第２係合部材の何れか一
方により内周側が軸受を介して回転自在に支持され単一
部材の中間回転部材と、 前記入力回転部材と中間回転部材の間に設けられた第１
渦巻ばね及び前記中間回転部材と出力回転部材の間に設
けられた第２渦巻ばねとよりなるアシスト遅れ回避機構
を備えたことを特徴とする四輪操舵装置。1. A four-wheel steering system comprising a front-wheel steering system for steering front wheels, a rear-wheel steering system for steering rear wheels, and a transmission system for interlocking the two steering systems. The four-wheel steering system is rotatably supported by a housing. An input rotary member that rotates in conjunction with steering of the front wheels, an output rotary member that is coaxially and axially spaced from the input rotary member in the housing and that steers the rear wheels, and an input rotary member An axial gap is provided between the first and second engagement members, which are rotatably supported coaxially via bearings on the inner peripheral side of the output rotary member, and the input and output rotary members, respectively. And a single member intermediate rotating member, which is coaxially arranged and whose inner peripheral side is rotatably supported by one of the first and second engaging members via a bearing, and the input rotating member and the intermediate rotating member. First provided between
A four-wheel steering system comprising: a spiral spring and an assist delay avoidance mechanism including a second spiral spring provided between the intermediate rotating member and the output rotating member.