JP3690877B2

JP3690877B2 - Rack and pinion type hydraulic power steering apparatus and manufacturing method thereof

Info

Publication number: JP3690877B2
Application number: JP17555496A
Authority: JP
Inventors: 裕人佐々木; 修佐野; 圭司岸本
Original assignee: Koyo Seiko Co Ltd
Current assignee: Koyo Seiko Co Ltd
Priority date: 1995-09-26
Filing date: 1996-06-14
Publication date: 2005-08-31
Anticipated expiration: 2016-06-14
Also published as: JPH09150749A

Description

【０００１】
【発明の属する技術分野】
本発明は、操舵補助力発生用油圧アクチュエータに作用する油圧を制御弁によって制御するラックピニオン式油圧パワーステアリング装置と、その製造方法に関する。
【０００２】
【従来の技術】
ラックピニオン式油圧パワーステアリング装置においては、操舵抵抗に応じ開度が変化する複数の絞り部を有する油圧制御弁を用い、その絞り部の開度を操舵抵抗に応じ変化させることで、操舵補助力発生用油圧アクチュエータに作用する油圧を制御している。
【０００３】
そのようなラックピニオン式油圧パワーステアリング装置においては、その制御弁は、バルブハウジングと、このバルブハウジングに相対回転可能に挿入される筒状の第１バルブ部材と、この第１バルブ部材に操舵抵抗に応じ相対回転可能に挿入される第２バルブ部材と、両バルブ部材の相対回転角度に応じて開度が変化する複数の絞り部とを有し、その第１バルブ部材に同行回転するよう連結される出力シャフトにピニオンが形成される。
その各絞り部の開度の変化により操舵方向と操舵抵抗に応じた操舵補助力を付与できるように、その制御弁とポンプ、アクチュエータおよびタンクそれぞれとの配管接続のための接続ポートがバルブハウジングに設けられている。
【０００４】
通常の種類のラックピニオン式油圧パワーステアリング装置にあっては、その各絞り部それぞれにおける操舵抵抗の変化に対する油圧変化割合は相等しくされている。
【０００５】
一方、そのアクチュエータに作用する油圧に対する操舵抵抗の関係を、車速や操舵角等の運転条件に応じて変化させ、高速になる程に操舵の安定性を向上すると共に低速になる程に操舵の応答性を向上することを図ったラックピニオン式油圧パワーステアリング装置もある。
そのような付加機能を有する種類のラックピニオン式油圧パワーステアリング装置においては、上記通常のラックピニオン式油圧パワーステアリング装置と同様の構成に加えて、各絞り部は第１の組と第２の組とに組分けされ、第１の組に属する絞り部では第２の組に属する絞り部よりも操舵抵抗の変化に対する油圧変化割合が大きくされ、第１の組に属する絞り部により制御される圧油流量の第２の組に属する絞り部により制御される圧油流量に対する割合を変化させることができるように、その第２の組に属する絞り部とタンクとの間の油路に、運転条件に応じ自身の絞り部の開度を変化させる可変絞り弁が設けられている。
【０００６】
【発明が解決しようとする課題】
従来、制御弁をポンプ、アクチュエータおよびタンクに配管接続するための各接続ポートのピニオンからの軸方向寸法は、通常の種類のラックピニオン式パワーステアリング装置と付加機能を有する種類のラックピニオン式パワーステアリング装置とで相異なるものであった。
すなわち、付加機能を有する種類のラックピニオン式油圧パワーステアリング装置においては、バルブハウジングにおける制御弁と可変絞り弁との接続ポートを、ポンプおよびアクチュエータとの接続ポートよりもピニオンに軸方向に近接して配置していたので、ピニオンからポンプおよびアクチュエータとの接続ポートまでの軸方向寸法は、通常の種類のラックピニオン式パワーステアリング装置よりも付加機能を有する種類のラックピニオン式パワーステアリング装置のほうが大きくなっていた。
また、付加機能を有する種類のラックピニオン式油圧パワーステアリング装置の場合、可変絞り弁のハウジングは、制御弁のバルブハウジングと一体成形されていた。
そのため、通常の種類のラックピニオン式油圧パワーステアリング装置と付加機能を有する種類のラックピニオン式油圧パワーステアリング装置とで、バルブハウジングの形状が大きく異なり、部品の共通化が阻害され、コスト低減を図ることができなかった。
さらに、通常の種類のラックピニオン式油圧パワーステアリング装置と付加機能を有する種類のラックピニオン式油圧パワーステアリング装置とで油圧配管の共通化が阻害され、コスト低減を図ることができなかった。
【０００７】
また、付加機能を有する種類のラックピニオン式油圧パワーステアリング装置においては、バルブハウジングにおける制御弁と可変絞り弁との接続ポートを、ポンプおよびアクチュエータとの接続ポートよりもピニオンに軸方向に近接して配置し、且つ、制御弁とタンクとの接続ポートを、第１バルブ部材よりもピニオンから軸方向に離れたバルブハウジング内部空間を介して制御弁に通じるように、第１バルブ部材よりもピニオンから軸方向に離れて配置していた。
そのため、制御弁と可変絞り弁との接続ポートと、制御弁とタンクとの接続ポートとの間の距離が大きかった。
しかし、その接続ポート間の距離が大きいと、可変絞り弁と制御弁との間の油の流路が長くなるため、可変絞り弁のハウジングが大型化するという問題があった。
【０００８】
本発明は、上記課題を解決することのできるラックピニオン式油圧パワーステアリング装置と、その製造方法を提供することを目的とする。
【０００９】
【課題を解決するための手段】
本発明方法は、２種類のラックピニオン式油圧パワーステアリング装置であって、それぞれ操舵補助力発生用油圧アクチュエータと、そのアクチュエータに作用する油圧の制御弁とを備えるものを製造する際に適用される。
その制御弁は、バルブハウジングと、このバルブハウジングに相対回転可能に挿入される筒状の第１バルブ部材と、この第１バルブ部材に操舵抵抗に応じ相対回転可能に挿入される第２バルブ部材と、両バルブ部材の相対回転角度に応じて開度が変化する複数の絞り部とを有する。その第１バルブ部材に同行回転するよう連結される出力シャフトにピニオンが形成される。
その各絞り部の開度の変化により操舵方向と操舵抵抗に応じた操舵補助力を付与できるように、その制御弁とポンプ、アクチュエータおよびタンクそれぞれとの配管接続のための接続ポートがバルブハウジングに設けられる。
一方の種類のラックピニオン式油圧パワーステアリング装置の各絞り部それぞれにおける操舵抵抗の変化に対する油圧変化割合は相等しくされる。
他方の種類のラックピニオン式油圧パワーステアリング装置の各絞り部は第１の組と第２の組とに組分けされ、第１の組に属する絞り部では第２の組に属する絞り部よりも操舵抵抗の変化に対する油圧変化割合が大きくされ、第１の組に属する絞り部により制御される圧油流量の第２の組に属する絞り部により制御される圧油流量に対する割合を変化させることができるように、その第２の組に属する絞り部とタンクとの間の油路に、運転条件に応じ自身の絞り部の開度を変化させる可変絞り弁が設けられている。
本発明は、上記２種類のラックピニオン式油圧パワーステアリング装置を製造するに際し、一方の種類のステアリング装置におけるピニオンから前記各接続ポートまでの軸方向寸法と、他方の種類のステアリング装置におけるピニオンから前記各接続ポートまでの軸方向寸法とを相等しくし、前記可変絞り弁のハウジングを他方の種類のステアリング装置のバルブハウジングとは別体とすることを特徴とする。
【００１０】
本発明方法によれば、制御弁をポンプとアクチュエータとタンクとに配管接続するための各接続ポートまでの、ピニオンからの軸方向寸法を、一方の種類のステアリング装置と他方の種類のステアリング装置とで等しくし、また、可変絞り弁のハウジングを他方の種類のラックピニオン式油圧パワーステアリング装置のバルブハウジングとは別体とすることで、一方の種類のステアリング装置と他方の種類のステアリング装置とでバルブハウジングの形状が異なるのを防止できる。
【００１１】
本発明方法において、各種類のステアリング装置におけるタンクとの接続ポートを、第１バルブ部材よりもピニオンから軸方向に離れたバルブハウジング内部空間を介して制御弁に通じるように、第１バルブ部材よりもピニオンから軸方向に離れて配置し、他方の種類のステアリング装置における第１バルブ部材の軸方向寸法を、一方の種類のステアリング装置における第１バルブ部材の軸方向寸法よりも長くし、他方の種類のステアリング装置のバルブハウジングにおける制御弁と可変絞り弁との接続ポートを、ポンプおよびアクチュエータとの接続ポートよりもピニオンから軸方向に離れて配置するのが好ましい。
【００１２】
他方の種類のステアリング装置においては、制御弁に可変絞り弁を接続するため、その接続のための油の流路を確保する必要があり、そのため、第１バルブ部材の軸方向寸法は、一方の種類のステアリング装置におけるよりも長くなる。
一方、従来より、ラックピニオン式油圧パワーステアリング装置におけるタンクとの接続ポートは、第１バルブ部材よりもピニオンから軸方向に離れたバルブハウジング内部空間を介して制御弁に通じるように、第１バルブ部材よりもピニオンから軸方向に離れて配置されている。
よって、他方の種類のステアリング装置のバルブハウジングにおける制御弁と可変絞り弁との接続ポートを、ポンプおよびアクチュエータとの接続ポートよりもピニオンから軸方向に離れて配置することで、他方の種類のステアリング装置における第１バルブ部材の軸方向寸法が一方の種類のステアリング装置の軸方向寸法よりも長尺であっても、その長尺部分の軸方向寸法を、他方の種類のステアリング装置のバルブハウジングの内部空間の軸方向寸法よりも小さくすることで、従来より用いられている一方の種類のステアリング装置のバルブハウジングの内部空間の一部に、その他方の種類のステアリング装置の第１バルブ部材を配置することができる。
これにより、従来より用いられている一方の種類のステアリング装置のバルブハウジングを、他方の種類のステアリング装置のバルブハウジングとして利用できる。また、従来より用いられている一方の種類のステアリング装置の出力シャフト等も、そのまま他方の種類のステアリング装置の部品として利用できる。
【００１３】
また、本発明方法において、一方の種類のステアリング装置における制御弁をポンプとアクチュエータとタンクとに接続する配管の配置と、他方の種類のステアリング装置における制御弁をポンプとアクチュエータとタンクとに接続する配管の配置とを相等しくするのが好ましい。
これにより、一方の種類のステアリング装置と他方の種類のステアリング装置とで、油圧配管を共通化してコスト低減を図ることができる。
【００１４】
さらに、本発明方法において、その可変絞り弁を、他方の種類のステアリング装置のバルブハウジングに着脱可能とし、一方の種類のステアリング装置のバルブハウジングおよび各バルブ部材として、他方の種類のステアリング装置の制御バルブを構成可能なものを使用し、他方の種類のステアリング装置においては可変絞り弁との接続ポートとして用いられるバルブハウジングの開口を、一方の種類のステアリング装置においては着脱可能な閉鎖部材により閉鎖するのが好ましい。
これにより、一方の種類のステアリング装置と他方の種類のステアリング装置とで、制御バルブの構成部品を共通化してコスト低減を図ることができる。
さらに、一方の種類のステアリング装置のバルブハウジングの開口を閉鎖する閉鎖部材を取り外し、その開口を接続ポートとしてバルブハウジングに他方の種類のステアリング装置と共通の可変絞り弁を接続することで、一方の種類のステアリング装置を他方の種類のステアリング装置にすることができる。
【００１５】
本発明の第１の油圧パワーステアリング装置は、上記他方の種類のラックピニオン式油圧パワーステアリング装置であって、前記制御弁とタンクとの接続ポートは、第１バルブ部材よりもピニオンから軸方向に離れたバルブハウジング内部空間を介して制御弁に通じるように、第１バルブ部材よりもピニオンから軸方向に離れて配置され、その制御弁と可変絞り弁との接続ポートは、その制御弁とポンプおよびアクチュエータとの接続ポートよりもピニオンから軸方向に離れて配置されていることを特徴とする。
【００１６】
本発明の第１の油圧パワーステアリング装置によれば、制御弁と可変絞り弁との接続ポートと、制御弁とタンクとの接続ポートと間の距離が、従来よりも短くなるので、可変絞り弁と制御弁との間の油の流路を短くできる。これにより、可変絞り弁のハウジングを小型化できる。
【００１７】
また、その可変絞り弁がスプールの軸方向移動により自身の絞り部の開度を変化させ、そのスプールの軸心を含む平面と両バルブ部材の相対回転軸を含む平面とが平行とされ、そのスプールの径方向外方に制御弁と可変絞り弁との間の油の流路が設けられることで、その油の流路を可及的に短くし、両バルブ部材の相対回転軸方向における可変絞り弁のハウジングの寸法を可及的に小さくできる。これにより、装置の小型軽量化を図ることができる。
【００１８】
さらに、両バルブ部材の相対回転軸方向における可変絞り弁のハウジングの寸法を可及的に小さくできるので、そのスプールの軸心を両バルブ部材の相対回転軸に非平行とすることで、可変絞り弁と他部品との干渉等を防止し、可変絞り弁をスペースの制限された場所に容易に配置できる。
【００１９】
本発明の第２の油圧パワーステアリング装置は、上記一方の種類のラックピニオン式油圧パワーステアリング装置であって、そのバルブハウジングに前記制御弁に通じる開口が形成され、その開口を閉鎖する閉鎖部材がバルブハウジングに着脱可能に取り付けられ、前記複数の絞り部は第１の組と第２の組とに組分けされ、その開口の閉鎖により、その第１の組の各絞り部それぞれにおける操舵抵抗の変化に対する油圧変化割合は相等しくされ、その第２の組の各絞り部での圧油の流れが阻止され、その開口を接続ポートとして、そのバルブハウジングに、その第２の組に属する絞り部とタンクとの間の油路において、運転条件に応じ自身の絞り部の開度を変化させる可変絞り弁が着脱可能とされ、その可変絞り弁を介して前記第２の組に属する絞り部とタンクとの間の油路が開くことで、前記第１の組に属する絞り部では第２の組に属する絞り部よりも操舵抵抗の変化に対する油圧変化割合が大きくされ、その可変絞り弁の絞り部の開度変化により、その第１の組に属する絞り部により制御される圧油流量の第２の組に属する絞り部により制御される圧油流量に対する割合が変化されることを特徴とする。
本発明の第２の油圧パワーステアリング装置によれば、バルブハウジングの開口を閉鎖する閉鎖部材を、他方の種類のステアリング装置と共通の可変絞り弁に交換することで、上記他方の種類のステアリング装置にすることができる。
【００２０】
【発明の実施の形態】
以下、図１〜図１１を参照して本発明の第１実施形態を説明する。
【００２１】
図１に示す第１のラックピニオン式油圧パワーステアリング装置（他方の種類のラックピニオン式油圧パワーステアリング装置）１は、車両のハンドル（図示省略）に連結される入力シャフト２と、この入力シャフト２にトーションバー６を介し連結される出力シャフト３とを備えている。そのトーションバー６は、ピン４により入力シャフト２に連結され、セレーション５により出力シャフト３に連結されている。その入力シャフト２は、ベアリング８を介しバルブハウジング７により支持され、また、ベアリング１２を介し出力シャフト３により支持されている。その出力シャフト３はベアリング１０、１１を介しラックハウジング９により支持されている。その出力シャフト３にピニオン１５が形成され、このピニオン１５に噛み合うラック１６に操舵用車輪（図示省略）が連結される。これにより、操舵による入力シャフト２の回転は、トーションバー６を介してピニオン１５に伝達される。そのピニオン１５の回転により、ラック１６は車両幅方向に移動し、このラック１６の移動により車両の操舵がなされる。なお、入出力シャフト２、３とバルブハウジング７との間にはオイルシール４２、４３が介在する。また、ラック１６を支持するサポートヨーク４０が、バネ４１の弾力によりラック１６に押し付けられている。
【００２２】
操舵補助力発生用油圧アクチュエータとして油圧シリンダ２０が設けられている。この油圧シリンダ２０は、ラックハウジング９により構成されるシリンダチューブと、ラック１６に一体化されるピストン２１とを備えている。そのピストン２１により仕切られる油室２２、２３に、操舵方向と操舵抵抗とに応じて圧油を供給するため、ロータリー式油圧制御弁３０が設けられている。
【００２３】
その制御弁３０は、バルブハウジング７に相対回転可能に挿入されている筒状の第１バルブ部材３１と、この第１バルブ部材３１に同軸中心に相対回転可能に挿入されている第２バルブ部材３２とを備えている。その第１バルブ部材３１は出力シャフト３に、ピン２９により同行回転するよう連結されている。その第２バルブ部材３２は、入力シャフト２と一体的に成形されている。すなわち、入力シャフト２の外周部により第２バルブ部材３２が構成され、第２バルブ部材３２は入力シャフト２と同行回転する。よって、第１バルブ部材３１と第２バルブ部材３２とは、操舵抵抗に応じ前記トーションバー６がねじれることで、同軸中心に相対回転する。
【００２４】
そのバルブハウジング７に、ポンプ７０に接続される入口ポート３４と、前記油圧シリンダ２０の一方の油室２２に接続される第１ポート３７と、他方の油室２３に接続される第２ポート３８と、直接にタンク７１に接続される第１出口ポート３６と、後述の可変絞り弁６０を介しタンク７１に接続される第２出口ポート６１とが設けられている。
その第１出口ポート３６は、第１バルブ部材３１よりもピニオン１５から軸方向に離れたバルブハウジング内部空間７ａを介して制御弁３０に通じるように、第１バルブ部材３１よりもピニオン１５から軸方向に離れて配置されている。
その第２出口ポート６１は、入口ポート３４、第１ポート３７および第２ポート３８よりもピニオン１５から軸方向に離れて配置されている。
【００２５】
上記各接続ポート３４、３６、３７、３８、６１は、その第１バルブ部材３１と第２バルブ部材３２との内外周間の弁間流路を介し互いに接続される。すなわち、図３、図４に示すように、第１バルブ部材３１の内周に８ケの凹部５０ａ、５０ｂ、５０ｃが周方向に関し互いに等間隔に形成され、第２バルブ部材３２の外周に８ケの凹部５１ａ、５１ｂ、５１ｃが周方向に関し互いに等間隔に形成されている。図４は実線により第２バルブ部材３２の展開図を示し、鎖線により第１バルブ部材３１に形成された凹部５０ａ、５０ｂ、５０ｃを示す。第１バルブ部材３１に形成された凹部５０ａ、５０ｂ、５０ｃの間に第２バルブ部材３２に形成された凹部５１ａ、５１ｂ、５１ｃが位置する。
【００２６】
その第１バルブ部材３１に形成された凹部は、２ケの右操舵用凹部５０ａと、２ケの左操舵用凹部５０ｂと、４ケの連絡用凹部５０ｃとを構成する。その２ケの右操舵用凹部５０ａは、第１バルブ部材３１に形成された流路５３と前記第１ポート３７とを介し油圧シリンダ２０の右操舵補助力発生用油室２２に接続され、互いに周方向に１８０°離れて配置される。その２ケの左操舵用凹部５０ｂは、第１バルブ部材３１に形成された流路５４と前記第２ポート３８とを介し油圧シリンダ２０の左操舵補助力発生用油室２３に接続され、互いに周方向に１８０°離れて配置される。なお、第１バルブ部材３１に形成された流路５３、５４は、径方向外方側において周溝状とされている。
【００２７】
その第２バルブ部材３２に形成された凹部は、４ケの圧油供給用凹部５１ａと、２ケの第１圧油排出用凹部５１ｂと、２ケの第２圧油排出用凹部５１ｃとを構成する。その４ケの圧油供給用凹部５１ａは、第１バルブ部材３１に形成された圧油供給路５５と前記入口ポート３４とを介しポンプ７０に接続され、互いに周方向に９０°離れて配置される。その２ケの第１圧油排出用凹部５１ｂは、入力シャフト２に形成された流路５２ａから入力シャフト２とトーションバー６との間を通り、入力シャフト２に形成された流路５２ｂ（図１参照）と第１出口ポート３６とを介しタンク７１に接続され、互いに周方向に１８０°離れて配置される。その２ケの第２圧油排出用凹部５１ｃは、第１バルブ部材３１に形成された流路５９と第２出口ポート６１とを介し可変絞り弁６０に接続され、互いに周方向に１８０°離れて配置されている。なお、第１バルブ部材３１に形成された圧油供給路５５と流路５９は、径方向外方側において周溝状とされている。
【００２８】
各第１圧油排出用凹部５１ｂは右操舵用凹部５０ａと左操舵用凹部５０ｂとの間に配置され、各第２圧油排出用凹部５１ｃは連絡用凹部５０ｃの間に配置され、右操舵用凹部５０ａと連絡用凹部５０ｃとの間および左操舵用凹部５０ｂと連絡用凹部５０ｃとの間に圧油供給用凹部５１ａは配置される。
【００２９】
その第１バルブ部材３１に形成された凹部５０ａ、５０ｂ、５０ｃの軸方向に沿う縁と第２バルブ部材３２に形成された凹部５１ａ、５１ｂ、５１ｃの軸方向に沿う縁との間が絞り部Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′を構成する。これにより、各絞り部Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′はポンプ７０とタンク７１と油圧シリンダ２０とを接続する弁間流路２７に配置されている。
【００３０】
図５に示すように、その第２バルブ部材３２に形成された凹部５１ａ、５１ｂ、５１ｃの軸方向に沿う縁は面取り部とされている。その連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′における第２圧油排出用凹部５１ｃの軸方向に沿う縁（図３において△で囲む）の面取り部の幅をＷ、圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′における圧油供給用凹部５１ａの軸方向に沿う縁（図３において□で囲む）の面取り部の幅をＷ′、その他の第２バルブ部材３２に形成された凹部の軸方向に沿う縁（図３において○で囲む）の面取り部の幅をＷ″として、図４、図５に示すように、Ｗ＞Ｗ′＞Ｗ″とされている。操舵抵抗のない状態（図４、図５の状態）にある各絞り部Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′を全閉するのに要する両バルブ部材３１、３２の相対回転角度（以下、「閉鎖角度」という）を互いに比較すると、連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′の閉鎖角度θｒは、圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′の閉鎖角度θｓよりも大きく、両閉鎖角度θｒ、θｓは、他の各絞り部Ａ、Ｂ、Ｃ、Ｄの閉鎖角度θｔよりも大きい。これにより、第１バルブ部材３１と第２バルブ部材３２との間の各絞り部は、複数の絞り部Ａ、Ｂ、Ｃ、Ｄからなる第１の組と、第１の組に属する各絞り部Ａ、Ｂ、Ｃ、Ｄよりも閉鎖角度の大きな複数の絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′からなる第２の組とに組分けされる。また、第２の組に属する絞り部は、圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′と、この絞り部Ａ′、Ｃ′よりも閉鎖角度の大きな連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′の２種類とされる。
【００３１】
その入力シャフト２と出力シャフト３は、路面から操舵用車輪を介し伝達される抵抗によるトーションバー６のねじれによって相対回転する。その相対回転により第１バルブ部材３１と第２バルブ部材３２とが相対回転することで、各絞り部Ａ、Ｂ、Ｃ、Ｄ、Ａ′、Ｂ′、Ｃ′、Ｄ′の開度が変化し、油圧シリンダ２０が操舵方向と操舵抵抗に応じた操舵補助力を発生する。第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄは第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′よりも、閉鎖角度が小さいので、その操舵抵抗の変化に対する油圧変化割合は大きくなる。
【００３２】
すなわち、図４は操舵が行なわれていない状態を示す。この状態では両バルブ部材３１、３２の間の絞り部Ａ、Ｂ、Ｃ、Ｄ、Ａ′、Ｂ′、Ｃ′、Ｄ′は全て開かれ、入口ポート３４と各出口ポート３６、６１とは弁間流路２７を介し連通するので、ポンプ７０から制御弁３０に流入する油はタンク７１に還流し、操舵補助力は発生しない。
【００３３】
この状態から右方へ操舵することによって生じる操舵抵抗により両バルブ部材３１、３２が相対回転すると、図３に示すように、圧油供給用凹部５１ａと右操舵用凹部５０ａとの間の絞り部Ａおよび左操舵用凹部５０ｂに隣接する圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′の開度が大きくなり、右操舵用凹部５０ａと第１圧油排出用凹部５１ｂとの間の絞り部Ｂおよび左操舵用凹部５０ｂに隣接する圧油供給用凹部５１ａに隣接する連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′の開度が小さくなり、圧油供給用凹部５１ａと左操舵用凹部５０ｂとの間の絞り部Ｃおよび右操舵用凹部５０ａに隣接する圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ｃ′の開度が小さくなり、左操舵用凹部５０ｂと第１圧油排出用凹部５１ｂとの間の絞り部Ｄおよび右操舵用凹部５０ａに隣接する圧油供給用凹部５１ａに隣接する連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｄ′の開度が大きくなる。これにより、図中矢印で示す圧油の流れにより油圧シリンダ２０の右操舵補助力発生用油室２２に操舵方向と操舵抵抗に応じた圧力の圧油が供給され、また、左操舵補助力発生用油室２３からタンク７１に油が還流し、車両の右方への操舵補助力が油圧シリンダ２０からラック１６に作用する。
【００３４】
左方へ操舵すると、第１バルブ部材３１と第２バルブ部材３２とは、右方に操舵した場合と逆方向に相対回転し、絞り部Ａ、Ａ′の開度が小さくなり、絞り部Ｂ、Ｂ′の開度が大きくなり、絞り部Ｃ、Ｃ′の開度が大きくなり、絞り部Ｄ、Ｄ′の開度が小さくなるの。よって、車両の左方への操舵補助力が油圧シリンダ２０からラック１６に作用する。
【００３５】
図１、図８に示すように、その第２出口ポート６１に連通する可変絞り弁６０は、バルブハウジング７とは別体の第２バルブハウジング７′と、この第２バルブハウジング７′に形成された挿入孔６６に軸方向（図１、図８において上下方向）に移動可能に挿入されたスプール６２と、そのスプール６２にねじ合わされるネジ部材６４とを有する。その第２バルブハウジング７′がバルブハウジング７にボルト等により接続されることで、この可変絞り弁６０はバルブハウジング７に着脱可能とされている。そのスプール６２の軸心は両バルブ部材３１、３２の相対回転軸に平行とされている。その挿入孔６６の一端はプラグ６８により閉鎖され、他端はカバー９４′により閉鎖されている。そのスプール６２とプラグ６８との間に圧縮コイルバネ９０が配置されている。そのネジ部材６４にステッピングモータ８０が接続され、そのステッピングモータ８０にコントローラ（図示省略）が接続される。そのコントローラは車速センサ（図示省略）に接続され、そのステッピングモータ８０を車速に応じ制御する。すなわち、高速になるとネジ部材６４は一方向に回転してスプール６２は図中上方に変位し、低速になるとネジ部材６４は他方向に回転してスプール６２は図中下方に変位する。
【００３６】
そのスプール６２の外周に周溝６２ａが形成され、その挿入孔６６の内周に周溝６６ａが形成され、両周溝６２ａ、６６ａの間が絞り部６７とされている。その絞り部６７の開度は、高速になってスプール６２が図中上方に変位すると大きくなり、低速になってスプール６２が下方に変位すると小さくなる。
【００３７】
その挿入孔６６の内周の周溝６６ａと第２出口ポート６１とを連通する連絡流路５８が、スプール６２の径方向外方において第２バルブハウジング７′に形成され、図９に示すように、その連絡流路５８からの圧油の漏れを防止するため、そのバルブハウジング７と第２バルブハウジング７′との間にリング状のシール部材９８ａが配置されている。
そのスプール６２の外周の周溝６２ａとスプール６２の通孔６２ｄとを連通する径方向孔６２ｃがスプール６２に形成されている。
そのスプール６２の通孔６２ｄは、その挿入孔６６におけるスプール６２の下方空間に連絡する。
そのスプール６２の下方空間と第１出口ポート３６とを連通する連絡流路７６が、スプール６２の径方向外方においてバルブハウジング７と第２バルブハウジング７′とに亘り形成されている。その連絡流路７６からの圧油の漏れを防止するため、図９に示すように、そのバルブハウジング７と第２バルブハウジング７′との間にリング状のシール部材９８ｂが配置されている。
その連絡流路７６のバルブハウジング７に形成されている部分が、前記第２出口ポート６１と共に、そのバルブハウジング７への可変絞り弁６０の接続ポートを構成する。
これにより、ポンプ７０から供給される圧油は、前記弁間流路２７および第２出口ポート６１から連絡流路５８に導かれ、この連絡流路５８から絞り部６７に至り、この絞り部６７から連絡流路７６、第１出口ポート３６を介しタンク７１に至る。なお、スプール６２には通孔６２ｄと平行にドレン流路６２ｈが形成され、スプール６２の上方空間と下方空間とを接続する。
【００３８】
その絞り部６７の開度の最大値は、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の最大値（両バルブ部材３１、３２の相対回転角が大きくなる程に開度が小さくなる特性における最大値である。すなわち、右操舵時は絞り部Ｂ′、Ｃ′の全開度の最大値をいい、左操舵時は絞り部Ａ′、Ｄ′の全開度の最大値をいう。以下「全開度の最大値」という場合は同旨）以上、若しくは絞り機能を奏さなくなるまで大きくされている。その絞り部６７の開度の最小値は、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の最小値（両バルブ部材３１、３２の相対回転角が大きくなる程に開度が小さくなる特性における最小値である。すなわち、右操舵時は絞り部Ｂ′、Ｃ′の全開度の最小値をいい、左操舵時は絞り部Ａ′、Ｄ′の全開度の最小値をいい、全閉状態を含む。以下「全開度の最小値」という場合は同旨）以下とされる。
【００３９】
これにより、図２に示す油圧回路が構成され、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′とタンク７１との間の油路の開度が、車速に応じた可変絞り弁６０の作動により変化する。すなわち、第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄにより制御される圧油流量の、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′により制御される圧油流量に対する割合が、可変絞り弁６０の作動により変化する。
【００４０】
図７において、実線Ｘは、両バルブ部材３１、３２の相対回転角に対する第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄの開度の変化特性を示す。１点鎖線Ｕは、その相対回転角に対する第２の組に属する連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′の開度の変化特性を示す。１点鎖線Ｖは、その相対回転角に対する第２の組に属する圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′の開度の変化特性を示す。実線Ｙは、その相対回転角に対する第２の組に属する全ての絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の開度の合成した変化特性を示す。破線Ｒは、可変絞り弁６０により設定される可変絞り弁自身の絞り部６７ａ、６７ｂの中速走行時における開度を示す。
【００４１】
上記第１のパワーステアリング装置１によれば、低速走行時においては、スプール６２は図１、図８において下方に変位し、このスプール６２の変位により可変絞り弁６０の絞り部６７は全閉状態になる。よって、油圧シリンダ２０に作用する油圧は、第１の組の絞り部Ａ、Ｂ、Ｃ、Ｄの開度の変化特性線Ｘに応じ制御される。この場合、図６において一点鎖線で示すように、操舵入力トルクが小さく、両バルブ部材３１、３２の相対回転角が小さくても、第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄの開度を小さくし、操舵補助力を発生させる油圧の増加割合を大きくし、低速走行時における操舵の高応答性を満足させることができる。
【００４２】
高速走行時においては、スプール６２は図１、図８において上方に変位し、このスプール６２の変位によって可変絞り弁６０の絞り部６７の開度は、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の最大値以上になる。よって、油圧シリンダ２０に作用する油圧は、第２の組の絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の開度の変化特性線Ｙ及び第１の組の絞り部Ａ、Ｂ、Ｃ、Ｄの開度の変化特性線Ｘの合成特性に応じ制御される。この場合、図６において実線で示すように、操舵入力トルクを大きくし、両バルブ部材３１、３２の相対回転角を大きくしない限り、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の開度は小さくなることなく大きく保持され、操舵補助力を発生させる油圧の増加割合は小さいので、高速走行時における操舵の安定性を満足させることができる。
【００４３】
中速走行時においては、スプール６２の変位により可変絞り弁６０の絞り部６７の開度は、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の最小値よりも大きく最大値よりも小さくなる。これにより、図７に示すように、第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄが最小値（本実施形態では全閉状態）になるまでの間（図７において両バルブ部材の相対回転角がθａになるまでの間）は、その第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄの全開度の変化特性線Ｘに絞り部６７の開度の特性線Ｒを合成した特性に応じた操舵補助力が付与される。第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄが全閉状態になった時点から、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度が可変絞り弁６０の絞り部６７の開度よりも小さくなるまでの間（図７において両バルブ部材の相対回転角がθａとθｂとの間）では、操舵補助力は絞り部６７の開度により定まる一定値になる。しかる後に、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度が可変絞り弁６０の絞り部６７の開度よりも小さくなると、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の変化特性線Ｙに応じた操舵補助力が付与される。
【００４４】
その第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄが全閉状態になった後に、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度が可変絞り弁６０の絞り部６７の開度よりも小さくなるまでの間（θａ〜θｂの間）は、その第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′が全閉状態になる点と、第１の組に属する絞り部Ａ、Ｂ、Ｃ、Ｄが全閉状態になる点との差（θｃ−θａ）を小さくすることなく、小さくされている。すなわち、仮に、第２の組に属する圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′が、連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′と同様に図中１点鎖線Ｕで示す相対回転角に対する開度変化特性を有すると仮定すると、相対回転角に対する第２の組に属する全ての絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の全開度の合成変化特性は、図７において２点鎖線Ｍで示すものになる。そうすると、第２の組に属する絞り部Ａ′、Ｂ′、Ｃ′、Ｄ′の開度が、可変絞り弁６０の自身の絞り部６７ａ、６７ｂの開度よりも小さくなるまでの間（両バルブ部材の相対回転角がθａとθｄとの間）は大きくなるので、図６において２点鎖線で示すように、操舵補助力を操舵抵抗に応じ制御できない領域Ｌが大きくなる。これに対し、上記実施形態では、第２の組に属する圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′の閉鎖角度θｓは、連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′の閉鎖角度θｒよりも小さいので、中速走行時において操舵補助力を操舵抵抗に応じ制御できない領域を小さくできる。しかも、圧油供給用凹部５１ａと連絡用凹部５０ｃとの間の絞り部Ａ′、Ｃ′が全閉状態になる点（図７において両バルブ部材の相対回転角がθｅの点）では、連絡用凹部５０ｃと第２圧油排出用凹部５１ｃとの間の絞り部Ｂ′、Ｄ′は未だ閉じていないので、操舵補助力を操舵抵抗に応じ制御できる領域は小さくなることはない。
【００４５】
図１０、図１１は、第２のラックピニオン式油圧パワーステアリング装置（一方の種類のラックピニオン式油圧パワーステアリング装置）１０１を示す。なお、図１０、図１１において、第１のパワーステアリング装置１に対応する部分は、第１のパワーステアリング装置１の図面符号番号に１００を足して示す。
この第２のパワーステアリング装置１０１における第１のパワーステアリング装置１との相違は、まず、第２バルブ部材１３２に形成された凹部の軸方向に沿う縁（図１１において○で囲む）の面取り部の幅は全て相等しくされ、これにより、制御弁１３０の各絞り部Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′それぞれにおける操舵抵抗の変化に対する油圧変化割合は相等しくされ、各絞り部Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′の閉鎖角度は同一とされている。
また、この第２のパワーステアリング装置１０１における第１バルブ部材１３１の軸方向寸法は、第１のパワーステアリング装置１における第１バルブ部材３１の軸方向寸法よりも短くされている。
また、第１のパワーステアリング装置１における可変絞り弁６０、第２出口ポート６１、流路５９、第２圧油排出用凹部５１ｃ、および連絡流路７６は設けられず、第２圧油排出用凹部５１ｃに対応する凹部１５１ｃは、第１のパワーステアリング装置１における第１圧油排出用凹部５１ｂに対応する凹部１５１ｂと同様に、入力シャフト１０２に形成された流路１５２ａから入力シャフト１０２とトーションバー１０６との間を介して第１出口ポート１３６からタンク１７１に接続される。
他は第１のパワーステアリング装置１と同様の構成とされ、これにより、第２のパワーステアリング装置１０１は、操舵抵抗と操舵方向に応じた操舵補助力を付与できる点は第１のラックピニオン式油圧パワーステアリング装置１と同様であるが、その操舵補助力を車速等の運転条件に応じて変化させる付加機能はない。
【００４６】
上記第１のパワーステアリング装置１と第２のパワーステアリング装置１０１とを製造するに際し、図１、図１０に示すように、第１のパワーステアリング装置１におけるピニオン１５のラック１６との噛み合い中心から、入口ポート３４、第１ポート３７、第２ポート３８および第１出口ポート３６までの軸方向寸法ａ、ｂ、ｃ、ｄと、第２のパワーステアリング装置１０１におけるピニオン１１５のラック１１６との噛み合い中心から、入口ポート１３４、第１ポート１３７、第２ポート１３８および第１出口ポート１３６までの軸方向寸法ａ、ｂ、ｃ、ｄとを相等しくしている。また、第１のパワーステアリング装置１における制御弁３０をポンプ７０と油圧シリンダ２０とタンク７１とに接続する配管９１、９２、９３、９４の配置と、第２のパワーステアリング装置１０１における制御弁１３０をポンプ１７０とアクチュエータ１２０とタンク１７１とに接続する配管１９１、１９２、１９３、１９４の配置とを相等しくしている。
【００４７】
上記第１実施形態によれば、第１のパワーステアリング装置１と第２のパワーステアリング装置１０１とで、ピニオン１５、１１５のラック１６、１１６との噛み合い中心から、入口ポート３４、１３４、第１ポート３７、１３７、第２ポート３８、１３８および第１出口ポート３６、１３６までの軸方向寸法ａ、ｂ、ｃ、ｄは相等しく、また、可変絞り弁６０の第２バルブハウジング７′は、第１のパワーステアリング装置のバルブハウジング７とは別体であるので、第１のパワーステアリング装置１と第２のパワーステアリング装置１０１とでバルブハウジング７、１０７の形状が異なるのを防止できる。これにより、第１のパワーステアリング装置１のバルブハウジング７として、第２のパワーステアリング装置１０１のバルブハウジング１０７に、可変絞り弁６０の第２バルブハウジング７′を取り付けるための座面７ｂとボルト孔（図示省略）の加工を施し、制御弁３０と可変絞り弁６０との接続用第２出口ポート６１と連絡流路７６とを形成したものを用いることができ、また出力シャフト３、１０３およびトーションバー６、１０６は第１のパワーステアリング装置１と第２のパワーステアリング装置１０１とで同一のものを用いることができる。
【００４８】
また、第１、第２のパワーステアリング装置１、１０１における第１出口ポート３６、１３６は、第１バルブ部材３１、１３１よりもピニオン１５、１１５から軸方向に離れたバルブハウジング内部空間７ａ、１０７ａを介して制御弁３０、１３０に通じるように、第１バルブ部材３１、１３１よりもピニオン１５、１１５から軸方向に離れて配置されている。よって、第１のパワーステアリング装置１の第１バルブ部材３１の軸方向寸法が、可変絞り弁６０との接続のための油の流路５９を確保するために、第２のパワーステアリング装置１０１の第１バルブ部材１３１の軸方向寸法よりも長尺であっても、その長尺部分の軸方向寸法を、第２のパワーステアリング装置１０１のバルブハウジング１０７の内部空間１０７ａの軸方向寸法よりも小さくすることで、第２のパワーステアリング装置１０１のバルブハウジング１０７と同一の軸方向寸法のバルブハウジング７の内部空間７ａに、その第１バルブ部材３１を配置することが可能とされている。これにより、従来より用いられている第２のパワーステアリング装置１０１のバルブハウジング１０７を、第１のパワーステアリング装置１のバルブハウジング７として利用できる。
【００４９】
また、第１のパワーステアリング装置１によれば、制御弁３０と可変絞り弁６０との接続のための第２出口ポート６１と、制御弁３０とタンク７１との接続のための第１出口ポート３６との間の距離が、従来よりも短くなるので、可変絞り弁６０と制御弁３０との間の油の流路５８、７６を短くできる。これにより、第２バルブハウジング７′を小型化できる。
【００５０】
また、可変絞り弁６０はスプール６２の軸方向移動により自身の絞り部６７の開度を変化させ、そのスプール６２の軸心を含む平面と両バルブ部材３１、３２の相対回転軸を含む平面とは平行とされ、そのスプール６２の径方向外方において第２バルブハウジング７′に可変絞り弁６０と制御弁３０との間の油の流路５８、７６が設けられているので、その油の流路５８、７６を可及的に短くし、両バルブ部材３１、３２の相対回転軸方向における第２バルブハウジング７′の寸法を可及的に小さくできる。これにより、装置の小型軽量化を図ることができる。
【００５１】
さらに、両バルブ部材３１、３２の相対回転軸方向における第２バルブハウジング７′の寸法を可及的に小さくできることで、図１２の第２実施形態の第１のラックピニオン式油圧パワーステアリング装置１′に示すように、そのスプール６２の軸心を両バルブ部材３１、３２の相対回転軸に非平行とすることで、可変絞り弁６０と他部品との干渉等を防止し、可変絞り弁６０をスペースの制限された場所に容易に配置できる。他は第１実施形態と同様で、同一部分は同一符号で示す。なお、図１２に示した例では、スプール６２の軸方向は両バルブ部材３１、３２の相対回転軸方向に直角とされているが、直角に限定されず、周囲の他部品との関係に応じた方向とすればよい。
【００５２】
図１３は、第３実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１′を示す。このステアリング装置１０１′は、第１実施形態の第１のラックピニオン式油圧パワーステアリング装置１のバルブハウジング７から可変絞り弁６０を取り外し、代わって、閉鎖部材２０１をバルブハウジング７にボルト等によって着脱可能に取り付けることで構成されている。
そのバルブハウジング７に形成された開口であって、その第１のラックピニオン式油圧パワーステアリング装置１においては可変絞り弁６０との接続ポートとして用いられる第２出口ポート６１と連絡流路７６とが、その閉鎖部材２０１により閉鎖される。
他は第１実施形態の第１のラックピニオン式油圧パワーステアリング装置１と同様で、同一部分は同一符号で示す。
これにより、この第３実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１′は、その閉鎖部材２０１を除き、バルブハウジング７および各バルブ部材３１、３２を含めた全ての構成部品として、第１実施形態の第１のラックピニオン式油圧パワーステアリング装置１を構成可能なものが使用されている。
【００５３】
上記第３実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１′によれば、第１実施形態の第１のラックピニオン式油圧パワーステアリング装置１とで、構成部品を共通化してコスト低減を図ることができる。さらに、その閉鎖部材２０１に代えて可変絞り弁６０をバルブハウジング７に取り付けることで、第１のラックピニオン式油圧パワーステアリング装置１にすることができる。
【００５４】
図１４は第４実施形態の第１のラックピニオン式油圧パワーステアリング装置１″を示し、図１５は第４実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１″を示す。
その第４実施形態の第１のラックピニオン式油圧パワーステアリング装置１″の可変絞り弁６０″と、上記第１実施形態の第１のラックピニオン式油圧パワーステアリング装置１の可変絞り弁６０とは、スプール６２の移動方向を上下方向とした場合、互いに上下逆にバルブハウジング７に取り付けられている。
その第４実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１″は、第４実施形態の第１のラックピニオン式油圧パワーステアリング装置１″のバルブハウジング７から可変絞り弁６０″を取り外し、代わって、閉鎖部材２０１″をバルブハウジング７にボルト等によって着脱可能に取り付けることで構成されている。その閉鎖部材２０１″とバルブハウジング７との間には、第２出口ポート６１″と連絡流路７６″とから圧油が外部に漏れるのを防止するためにシール部材２０２″、２０３″が介在する。他は第１実施形態と同様で、同一部分は同一符号で示す。
この第４実施形態によれば第１実施形態と同様の作用効果を奏することができ、さらに、この第４実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１″によれば、第３実施形態の第２のラックピニオン式油圧パワーステアリング装置１０１′と同様の作用効果を奏することができる。
【００５５】
【発明の効果】
本発明方法によれば、通常の種類のラックピニオン式油圧パワーステアリング装置と付加機能を有する種類のラックピニオン式油圧パワーステアリング装置とで、部品の共通化によりコスト低減を図ることができ、また、油圧配管の共通化や、制御バルブの構成部品の共通化によってコスト低減を図ることができる。さらに、通常の種類のラックピニオン式油圧パワーステアリング装置を、容易に付加機能を有する種類のラックピニオン式油圧パワーステアリング装置に変更することが可能になる。本件第１の発明装置によれば、付加機能を有する種類のラックピニオン式油圧パワーステアリング装置における油の流路の加工を容易にでき、装置の小型軽量化を図ることができ、スペースの制限された場所に容易に配置できる。本件第２の発明装置によれば、付加機能を有する種類のラックピニオン式油圧パワーステアリング装置に容易に変更することができる通常の種類のラックピニオン式油圧パワーステアリング装置を提供できる。
【図面の簡単な説明】
【図１】本発明の第１実施形態の第１の油圧パワーステアリング装置の縦断面図
【図２】本発明の第１実施形態の第１の油圧パワーステアリング装置の油圧回路を示す図
【図３】本発明の第１実施形態の第１の油圧パワーステアリング装置における制御弁の横断面構造の説明図
【図４】本発明の第１実施形態の第１の油圧パワーステアリング装置の制御弁の展開図
【図５】本発明の第１実施形態の第１の油圧パワーステアリング装置の制御弁の要部の拡大図
【図６】本発明の第１実施形態の第１の油圧パワーステアリング装置における入力トルクと油圧との関係及び両バルブ部材の相対回転角と油圧との関係を示す図
【図７】本発明の第１実施形態の第１の油圧パワーステアリング装置における制御弁の絞り部の開度とバルブ部材の相対回転角との関係を示す図
【図８】本発明の第１実施形態の第１の油圧パワーステアリング装置の可変絞り弁の縦断面図
【図９】本発明の第１実施形態の第１の油圧パワーステアリング装置のバルブハウジングと可変絞り弁のハウジングの横断面図
【図１０】本発明の第１実施形態の第２の油圧パワーステアリング装置の縦断面図
【図１１】本発明の第１実施形態の第２の油圧パワーステアリング装置における制御弁の横断面構造の説明図
【図１２】本発明の第２実施形態の第１の油圧パワーステアリング装置の縦断面図
【図１３】本発明の第３実施形態の第２の油圧パワーステアリング装置の縦断面図
【図１４】本発明の第４実施形態の第１の油圧パワーステアリング装置の縦断面図
【図１５】本発明の第４実施形態の第２の油圧パワーステアリング装置の縦断面図
【符号の説明】
１、１′、１″ 第１の油圧パワーステアリング装置（他方の種類の油圧パワーステアリング装置）
３、１０３出力シャフト
７、１０７バルブハウジング
７ａ、１０７ａバルブハウジング内部空間
７′ 第２バルブハウジング
１５、１１５ピニオン
２０、１２０油圧シリンダ
３０、１３０制御弁
３１、１３１第１バルブ部材
３２、１３２第２バルブ部材
３４入口ポート
３６第１出口ポート
３７第１ポート
３８第２ポート
６０可変絞り弁
６１、６１″ 第２出口ポート
７０、１７０ポンプ
７１、１７１タンク
７６、７６″ 連絡流路
９１、９２、９３、９４、１９１、１９２、１９３、１９４配管
１０１、１０１′、１０１″ 第２の油圧パワーステアリング装置（一方の種類の油圧パワーステアリング装置）
２０１、２０１″ 閉鎖部材
Ａ、Ａ′、Ｂ、Ｂ′、Ｃ、Ｃ′、Ｄ、Ｄ′ 絞り部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a rack and pinion type hydraulic power steering apparatus that controls a hydraulic pressure acting on a hydraulic actuator for generating a steering assist force with a control valve, and a method for manufacturing the same.
[0002]
[Prior art]
In a rack and pinion type hydraulic power steering device, a steering assist force is obtained by using a hydraulic control valve having a plurality of throttle portions whose opening degree changes according to the steering resistance, and changing the opening degree of the throttle portion according to the steering resistance. The hydraulic pressure acting on the generating hydraulic actuator is controlled.
[0003]
In such a rack and pinion type hydraulic power steering device, the control valve includes a valve housing, a cylindrical first valve member inserted into the valve housing so as to be relatively rotatable, and a steering resistance against the first valve member. A second valve member inserted so as to be rotatable relative to the first valve member, and a plurality of throttle portions whose opening degrees change according to the relative rotation angles of the two valve members, and are connected to rotate together with the first valve member. A pinion is formed on the output shaft.
A connection port for pipe connection between the control valve and each of the pump, actuator and tank is provided in the valve housing so that a steering assist force according to the steering direction and the steering resistance can be applied by changing the opening of each throttle portion. Is provided.
[0004]
In a normal type rack-and-pinion type hydraulic power steering device, the hydraulic pressure change ratio with respect to the change of the steering resistance in each throttle portion is made equal.
[0005]
On the other hand, the relationship of the steering resistance to the hydraulic pressure acting on the actuator is changed according to the driving conditions such as the vehicle speed and the steering angle, so that the steering stability improves as the speed increases and the steering response increases as the speed decreases. There is also a rack and pinion type hydraulic power steering device which aims to improve the performance.
In the rack and pinion type hydraulic power steering apparatus having such an additional function, in addition to the same configuration as that of the normal rack and pinion type hydraulic power steering apparatus, each throttle unit includes the first group and the second group. In the throttle part belonging to the first group, the hydraulic pressure change ratio with respect to the change of the steering resistance is larger than the throttle part belonging to the second group, and the pressure controlled by the throttle part belonging to the first group In order to be able to change the ratio of the oil flow rate to the pressure oil flow rate controlled by the throttle unit belonging to the second set, the operating condition is set in the oil passage between the throttle unit belonging to the second set and the tank. Accordingly, there is provided a variable throttle valve that changes the opening of its throttle unit in response to the above.
[0006]
[Problems to be solved by the invention]
Conventionally, the axial dimension from the pinion of each connection port for pipe connection of the control valve to the pump, actuator and tank is the normal type of rack and pinion type power steering device and the type of rack and pinion type power steering having an additional function. It was different from the device.
That is, in a rack and pinion type hydraulic power steering device having an additional function, the connection port between the control valve and the variable throttle valve in the valve housing is closer to the pinion in the axial direction than the connection port between the pump and the actuator. As a result, the axial dimension from the pinion to the connection port of the pump and actuator is larger in the rack and pinion type power steering device having the additional function than the normal type rack and pinion type power steering device. It was.
In the case of a rack and pinion type hydraulic power steering device having an additional function, the housing of the variable throttle valve is integrally formed with the valve housing of the control valve.
For this reason, the shape of the valve housing differs greatly between the normal type of rack and pinion type hydraulic power steering device and the type of rack and pinion type hydraulic power steering device having an additional function. I couldn't.
Further, the common use of hydraulic piping is hindered by the normal type of rack and pinion type hydraulic power steering device and the type of rack and pinion type hydraulic power steering device having an additional function, and the cost cannot be reduced.
[0007]
In addition, in a rack and pinion type hydraulic power steering device having an additional function, the connection port between the control valve and the variable throttle valve in the valve housing is closer to the pinion in the axial direction than the connection port between the pump and the actuator. The connection port between the control valve and the tank is disposed from the pinion rather than the first valve member so that the connection port between the control valve and the tank communicates with the control valve via the valve housing internal space that is axially separated from the pinion than the first valve member. They were placed apart in the axial direction.
Therefore, the distance between the connection port between the control valve and the variable throttle valve and the connection port between the control valve and the tank is large.
However, if the distance between the connection ports is large, the oil flow path between the variable throttle valve and the control valve becomes long, and there is a problem that the housing of the variable throttle valve becomes large.
[0008]
An object of the present invention is to provide a rack and pinion type hydraulic power steering apparatus that can solve the above-described problems and a method for manufacturing the same.
[0009]
[Means for Solving the Problems]
The method of the present invention is applied when manufacturing two types of rack and pinion type hydraulic power steering devices each including a steering actuator generating hydraulic actuator and a hydraulic control valve acting on the actuator. .
The control valve includes a valve housing, a cylindrical first valve member that is inserted into the valve housing in a relatively rotatable manner, and a second valve member that is inserted into the first valve member in a relatively rotatable manner in accordance with a steering resistance. And a plurality of throttle portions whose opening degree changes according to the relative rotation angles of both valve members. A pinion is formed on the output shaft connected to the first valve member for accompanying rotation.
A connection port for pipe connection between the control valve and each of the pump, actuator and tank is provided in the valve housing so that a steering assist force according to the steering direction and the steering resistance can be applied by changing the opening of each throttle portion. Provided.
The hydraulic pressure change ratio with respect to the change of the steering resistance in each throttle part of one type of rack and pinion type hydraulic power steering apparatus is made equal.
Each throttle part of the other type of rack and pinion type hydraulic power steering apparatus is divided into a first group and a second group, and the throttle part belonging to the first group is more than the throttle part belonging to the second group. The hydraulic pressure change ratio with respect to the change in the steering resistance is increased, and the ratio of the pressure oil flow rate controlled by the throttle unit belonging to the first group to the pressure oil flow rate controlled by the throttle unit belonging to the second group is changed. In order to be able to do so, a variable throttle valve is provided in the oil passage between the throttle part and the tank belonging to the second set to change the opening degree of the throttle part according to the operating conditions.
In manufacturing the above-described two types of rack and pinion type hydraulic power steering devices, the axial dimension from the pinion to one of the connection ports in one type of steering device and the pinion in the other type of steering device The axial dimension to each connection port is made equal, and the housing of the variable throttle valve is separate from the valve housing of the other type of steering device.
[0010]
According to the method of the present invention, the axial dimension from the pinion to each connection port for connecting the control valve to the pump, the actuator, and the tank is determined using one type of steering device and the other type of steering device. In addition, the variable throttle valve housing is separated from the valve housing of the other type of rack and pinion type hydraulic power steering device, so that one type of steering device and the other type of steering device can It is possible to prevent the shape of the valve housing from being different.
[0011]
In the method of the present invention, the connection port with the tank in each type of steering device is communicated with the control valve via the internal space of the valve housing that is axially separated from the pinion than the first valve member. Are arranged apart from the pinion in the axial direction, and the axial dimension of the first valve member in the other type of steering device is made longer than the axial dimension of the first valve member in the one type of steering device. It is preferable that the connection port between the control valve and the variable throttle valve in the valve housing of the steering device of the type is arranged farther in the axial direction from the pinion than the connection port between the pump and the actuator.
[0012]
In the other type of steering device, since the variable throttle valve is connected to the control valve, it is necessary to secure an oil flow path for the connection. Therefore, the axial dimension of the first valve member is Longer than in the kind of steering device.
On the other hand, conventionally, the connection port with the tank in the rack and pinion type hydraulic power steering device communicates with the control valve via the valve housing internal space that is axially separated from the pinion than the first valve member. It arrange | positions in the axial direction away from the pinion rather than the member.
Therefore, the connection port between the control valve and the variable throttle valve in the valve housing of the other type of steering device is arranged farther away from the pinion than the connection port between the pump and the actuator, so that the other type of steering can be provided. Even if the axial dimension of the first valve member in the device is longer than the axial dimension of one type of steering device, the axial dimension of the elongated portion is the same as that of the valve housing of the other type of steering device. By making it smaller than the axial dimension of the internal space, the first valve member of the other type of steering device is arranged in a part of the internal space of the valve housing of one type of steering device used conventionally. can do.
Thereby, the valve housing of one type of steering device conventionally used can be used as the valve housing of the other type of steering device. In addition, the output shaft of one type of steering device that has been conventionally used can be used as it is as a component of the other type of steering device.
[0013]
Further, in the method of the present invention, the arrangement of piping for connecting the control valve in one type of steering device to the pump, the actuator and the tank, and the control valve in the other type of steering device is connected to the pump, the actuator and the tank. It is preferable to equalize the arrangement of the pipes.
As a result, the hydraulic piping can be shared between the one type of steering device and the other type of steering device to reduce costs.
[0014]
Further, in the method of the present invention, the variable throttle valve can be attached to and detached from the valve housing of the other type of steering device, and the control device of the other type of steering device can be used as the valve housing and each valve member of the one type of steering device. A valve that can be configured is used, and the opening of a valve housing used as a connection port with a variable throttle valve in the other type of steering device is closed by a detachable closing member in the one type of steering device. Is preferred.
As a result, the components of the control valve can be shared by one type of steering device and the other type of steering device, thereby reducing costs.
Further, by removing a closing member that closes the opening of the valve housing of one type of steering device and connecting the variable throttle valve common to the other type of steering device to the valve housing with the opening as a connection port, One type of steering device can be the other type of steering device.
[0015]
A first hydraulic power steering device according to the present invention is the other type of rack and pinion type hydraulic power steering device, wherein a connection port between the control valve and the tank is more axially away from the pinion than the first valve member. The first valve member is disposed more axially away from the pinion so as to communicate with the control valve via a remote valve housing internal space, and the connection port between the control valve and the variable throttle valve is provided between the control valve and the pump. And it is characterized in that it is arranged farther away from the pinion in the axial direction than the connection port with the actuator.
[0016]
According to the first hydraulic power steering apparatus of the present invention, the distance between the connection port between the control valve and the variable throttle valve and the connection port between the control valve and the tank is shorter than the conventional one. The oil flow path between the control valve and the control valve can be shortened. Thereby, the housing of a variable throttle valve can be reduced in size.
[0017]
In addition, the variable throttle valve changes the opening of its throttle part by the axial movement of the spool, and the plane including the axis of the spool and the plane including the relative rotation axis of both valve members are parallel to each other. By providing an oil flow path between the control valve and the variable throttle valve on the outer side in the radial direction of the spool, the oil flow path is made as short as possible and variable in the direction of the relative rotation axis of both valve members. The size of the throttle valve housing can be made as small as possible. Thereby, size reduction and weight reduction of an apparatus can be achieved.
[0018]
Furthermore, the size of the housing of the variable throttle valve in the relative rotational axis direction of both valve members can be made as small as possible. Therefore, by making the shaft center of the spool non-parallel to the relative rotational axis of both valve members, the variable throttle valve Interference between the valve and other parts can be prevented, and the variable throttle valve can be easily arranged in a space-limited place.
[0019]
A second hydraulic power steering device according to the present invention is the one type of rack and pinion type hydraulic power steering device, wherein an opening communicating with the control valve is formed in the valve housing, and a closing member for closing the opening is provided. The plurality of throttle portions are detachably attached to the valve housing, and are divided into a first group and a second group. By closing the opening, the steering resistance of each throttle unit of the first group is reduced. The hydraulic pressure change ratio with respect to the change is made equal, the flow of pressure oil in each throttle part of the second set is blocked, and the throttle part belonging to the second set is connected to the valve housing with the opening as a connection port. In the oil passage between the tank and the tank, a variable throttle valve that changes the opening of its throttle unit according to the operating conditions is detachable, and belongs to the second group via the variable throttle valve. When the oil passage between the throttle portion and the tank is opened, the throttle portion belonging to the first group has a higher hydraulic pressure change rate with respect to the change in steering resistance than the throttle portion belonging to the second group, and the variable The ratio of the pressure oil flow rate controlled by the throttle part belonging to the first group to the pressure oil flow rate controlled by the throttle part belonging to the second group is changed by the opening degree change of the throttle part of the throttle valve. It is characterized by.
According to the second hydraulic power steering apparatus of the present invention, the closing member for closing the opening of the valve housing is replaced with a variable throttle valve common to the other type of steering apparatus, whereby the other type of steering apparatus is provided. Can be.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The first embodiment of the present invention will be described below with reference to FIGS.
[0021]
A first rack and pinion hydraulic power steering device (the other type of rack and pinion hydraulic power steering device) 1 shown in FIG. 1 includes an input shaft 2 connected to a vehicle handle (not shown), and the input shaft 2. And an output shaft 3 connected via a torsion bar 6. The torsion bar 6 is connected to the input shaft 2 by a pin 4 and connected to the output shaft 3 by a serration 5. The input shaft 2 is supported by the valve housing 7 via a bearing 8 and supported by the output shaft 3 via a bearing 12. The output shaft 3 is supported by the rack housing 9 via bearings 10 and 11. A pinion 15 is formed on the output shaft 3, and a steering wheel (not shown) is connected to a rack 16 that meshes with the pinion 15. Thereby, the rotation of the input shaft 2 by steering is transmitted to the pinion 15 via the torsion bar 6. The rack 16 is moved in the vehicle width direction by the rotation of the pinion 15, and the vehicle is steered by the movement of the rack 16. Oil seals 42 and 43 are interposed between the input / output shafts 2 and 3 and the valve housing 7. A support yoke 40 that supports the rack 16 is pressed against the rack 16 by the elasticity of the spring 41.
[0022]
A hydraulic cylinder 20 is provided as a steering assist force generating hydraulic actuator. The hydraulic cylinder 20 includes a cylinder tube constituted by the rack housing 9 and a piston 21 integrated with the rack 16. In order to supply pressure oil to the oil chambers 22 and 23 partitioned by the piston 21 according to the steering direction and the steering resistance, a rotary hydraulic control valve 30 is provided.
[0023]
The control valve 30 includes a cylindrical first valve member 31 inserted into the valve housing 7 so as to be relatively rotatable, and a second valve member inserted into the first valve member 31 so as to be relatively rotatable about a coaxial center. 32. The first valve member 31 is connected to the output shaft 3 so as to rotate together with the pin 29. The second valve member 32 is formed integrally with the input shaft 2. That is, the second valve member 32 is configured by the outer peripheral portion of the input shaft 2, and the second valve member 32 rotates along with the input shaft 2. Therefore, the first valve member 31 and the second valve member 32 rotate relative to each other about the coaxial center by twisting the torsion bar 6 according to the steering resistance.
[0024]
The valve housing 7 has an inlet port 34 connected to the pump 70, a first port 37 connected to one oil chamber 22 of the hydraulic cylinder 20, and a second port 38 connected to the other oil chamber 23. And a first outlet port 36 directly connected to the tank 71 and a second outlet port 61 connected to the tank 71 via a variable throttle valve 60 described later.
The first outlet port 36 is connected to the control valve 30 via the valve housing internal space 7a that is axially separated from the pinion 15 than the first valve member 31 and is connected to the shaft from the pinion 15 rather than the first valve member 31. They are placed apart in the direction.
The second outlet port 61 is disposed farther away from the pinion 15 in the axial direction than the inlet port 34, the first port 37, and the second port 38.
[0025]
The connection ports 34, 36, 37, 38, 61 are connected to each other via an inter-valve flow path between the inner and outer periphery of the first valve member 31 and the second valve member 32. That is, as shown in FIGS. 3 and 4, eight recesses 50 a, 50 b, 50 c are formed at equal intervals in the circumferential direction on the inner periphery of the first valve member 31, and 8 recesses are formed on the outer periphery of the second valve member 32. The concave portions 51a, 51b and 51c are formed at equal intervals in the circumferential direction. FIG. 4 shows a developed view of the second valve member 32 by a solid line, and shows the recesses 50a, 50b, 50c formed in the first valve member 31 by a chain line. The recesses 51a, 51b, 51c formed in the second valve member 32 are located between the recesses 50a, 50b, 50c formed in the first valve member 31.
[0026]
The recesses formed in the first valve member 31 constitute two right steering recesses 50a, two left steering recesses 50b, and four communication recesses 50c. The two right steering recesses 50a are connected to the right steering assist force generating oil chamber 22 of the hydraulic cylinder 20 through the flow path 53 formed in the first valve member 31 and the first port 37, and are mutually connected. They are arranged 180 ° apart in the circumferential direction. The two left steering recesses 50b are connected to the left steering assist force generating oil chamber 23 of the hydraulic cylinder 20 through the flow path 54 formed in the first valve member 31 and the second port 38, and are mutually connected. They are arranged 180 ° apart in the circumferential direction. In addition, the flow paths 53 and 54 formed in the first valve member 31 have a circumferential groove shape on the radially outer side.
[0027]
The recesses formed in the second valve member 32 include four pressure oil supply recesses 51a, two first pressure oil discharge recesses 51b, and two second pressure oil discharge recesses 51c. Constitute. The four pressure oil supply recesses 51a are connected to the pump 70 via the pressure oil supply passage 55 formed in the first valve member 31 and the inlet port 34, and are disposed 90 ° apart from each other in the circumferential direction. The The two first pressure oil discharge recesses 51b pass between the input shaft 2 and the torsion bar 6 from the flow path 52a formed in the input shaft 2, and the flow path 52b formed in the input shaft 2 (FIG. 1) and the first outlet port 36, and is connected to the tank 71 and arranged 180 degrees apart from each other in the circumferential direction. The two second pressure oil discharge recesses 51c are connected to the variable throttle valve 60 via the flow path 59 formed in the first valve member 31 and the second outlet port 61, and are 180 ° apart from each other in the circumferential direction. Are arranged. The pressure oil supply path 55 and the flow path 59 formed in the first valve member 31 have a circumferential groove shape on the radially outer side.
[0028]
Each first pressure oil discharge recess 51b is disposed between the right steering recess 50a and the left steering recess 50b, and each second pressure oil discharge recess 51c is disposed between the communication recesses 50c. The pressure oil supply recess 51a is disposed between the recess 50a and the communication recess 50c and between the left steering recess 50b and the communication recess 50c.
[0029]
A constriction is defined between the edges along the axial direction of the recesses 50a, 50b and 50c formed in the first valve member 31 and the edges along the axial direction of the recesses 51a, 51b and 51c formed in the second valve member 32. A, A ′, B, B ′, C, C ′, D, D ′ are formed. Accordingly, the throttle portions A, A ′, B, B ′, C, C ′, D, and D ′ are arranged in the inter-valve flow path 27 that connects the pump 70, the tank 71, and the hydraulic cylinder 20.
[0030]
As shown in FIG. 5, the edges along the axial direction of the recesses 51a, 51b, 51c formed in the second valve member 32 are chamfered portions. Chamfering of an edge (enclosed by Δ in FIG. 3) along the axial direction of the second pressure oil discharge recess 51c at the throttle portions B ′ and D ′ between the communication recess 50c and the second pressure oil discharge recess 51c. The width of the portion is W, and the edge (enclosed by □ in FIG. 3) along the axial direction of the pressure oil supply recess 51a in the throttle portions A ′ and C ′ between the pressure oil supply recess 51a and the communication recess 50c. 4 and 5, where the width of the chamfered portion is W ′, and the width of the chamfered portion of the edge (encircled in FIG. 3) along the axial direction of the other concave portion formed in the second valve member 32 is W ″. As shown, W> W ′> W ″. Both valve members 31 required to fully close the throttle portions A, A ′, B, B ′, C, C ′, D, D ′ in a state without steering resistance (the state of FIGS. 4 and 5), 32 relative to each other (hereinafter referred to as “closing angle”), the closing angle θr of the throttle portions B ′ and D ′ between the communication recess 50c and the second pressure oil discharge recess 51c is equal to the pressure The closing angles θs of the throttles A ′ and C ′ between the oil supply recess 51a and the communication recess 50c are larger than the closing angles θr and θs of the other throttles A, B, C, and D. It is larger than the closing angle θt. Thereby, each throttle part between the 1st valve member 31 and the 2nd valve member 32 is each 1st group which consists of a plurality of throttle parts A, B, C, and D, and each throttle which belongs to the 1st group. They are grouped into a second group consisting of a plurality of throttle parts A ′, B ′, C ′, D ′ having a larger closing angle than the parts A, B, C, D. In addition, the throttle portions belonging to the second group have throttle portions A ′ and C ′ between the pressure oil supply concave portion 51a and the communication concave portion 50c, and a closing angle larger than the throttle portions A ′ and C ′. There are two types of throttle portions B ′ and D ′ between the communication recess 50c and the second pressure oil discharge recess 51c.
[0031]
The input shaft 2 and the output shaft 3 are relatively rotated by the torsion of the torsion bar 6 due to the resistance transmitted from the road surface via the steering wheel. Due to the relative rotation, the first valve member 31 and the second valve member 32 rotate relative to each other, so that the opening degree of each of the throttle portions A, B, C, D, A ′, B ′, C ′, and D ′ changes. Then, the hydraulic cylinder 20 generates a steering assist force according to the steering direction and the steering resistance. The apertures A, B, C, D belonging to the first group have smaller closing angles than the apertures A ′, B ′, C ′, D ′ belonging to the second group, so that the change in the steering resistance can be prevented. The hydraulic pressure change rate increases.
[0032]
That is, FIG. 4 shows a state where steering is not performed. In this state, the throttle portions A, B, C, D, A ′, B ′, C ′, and D ′ between the valve members 31 and 32 are all opened, and the inlet port 34 and the outlet ports 36 and 61 are Since the communication is made via the inter-valve flow path 27, the oil flowing from the pump 70 to the control valve 30 returns to the tank 71, and no steering assist force is generated.
[0033]
When the two valve members 31 and 32 are rotated relative to each other by steering resistance generated by steering to the right from this state, as shown in FIG. 3, the throttle portion between the pressure oil supply recess 51a and the right steering recess 50a. The opening of the throttle portion A ′ between the pressure oil supply recess 51a adjacent to the A and left steering recess 50b and the communication recess 50c increases, and the right steering recess 50a and the first pressure oil discharge recess 51b. The degree of opening of the throttle portion B 'between the communication recess 50c adjacent to the pressure oil supply recess 51a adjacent to the throttle portion B and the left steering recess 50b and the second pressure oil discharge recess 51c is between The throttle portion C 'between the pressure oil supply recess 51a and the communication recess 50c adjacent to the pressure oil supply recess 51a and the communication recess 50c is reduced. The opening of the left steering wheel is reduced, and the left steering recess 5 b and the first pressure oil discharge recess 51b and the communication pressure recess 50c adjacent to the pressure oil supply recess 51a adjacent to the right steering recess 50a and the second pressure oil discharge recess 51c. The opening degree of the throttle part D ′ increases. As a result, the pressure oil having the pressure corresponding to the steering direction and the steering resistance is supplied to the oil chamber 22 for generating the right steering assist force of the hydraulic cylinder 20 by the flow of the pressure oil indicated by the arrow in the drawing, and the left steering assist force is generated. Oil flows back from the oil chamber 23 to the tank 71, and a steering assist force to the right of the vehicle acts on the rack 16 from the hydraulic cylinder 20.
[0034]
When steered to the left, the first valve member 31 and the second valve member 32 rotate relative to each other in the direction opposite to that steered to the right, and the apertures of the throttling portions A and A ′ become smaller, and the throttling portion B , B ′ increases, the apertures C and C ′ increase, and apertures D and D ′ decrease. Therefore, a steering assist force to the left of the vehicle acts on the rack 16 from the hydraulic cylinder 20.
[0035]
As shown in FIGS. 1 and 8, a variable throttle valve 60 communicating with the second outlet port 61 is formed in a second valve housing 7 ′ separate from the valve housing 7 and in the second valve housing 7 ′. The spool 62 is inserted into the insertion hole 66 so as to be movable in the axial direction (vertical direction in FIGS. 1 and 8), and the screw member 64 is screwed into the spool 62. The variable throttle valve 60 can be attached to and detached from the valve housing 7 by connecting the second valve housing 7 ′ to the valve housing 7 with a bolt or the like. The axis of the spool 62 is parallel to the relative rotational axes of the valve members 31 and 32. One end of the insertion hole 66 is closed by a plug 68, and the other end is closed by a cover 94 '. A compression coil spring 90 is disposed between the spool 62 and the plug 68. A stepping motor 80 is connected to the screw member 64, and a controller (not shown) is connected to the stepping motor 80. The controller is connected to a vehicle speed sensor (not shown) and controls the stepping motor 80 according to the vehicle speed. That is, when the speed is high, the screw member 64 rotates in one direction and the spool 62 is displaced upward in the figure, and when the speed is low, the screw member 64 is rotated in the other direction and the spool 62 is displaced downward in the figure.
[0036]
A circumferential groove 62 a is formed on the outer periphery of the spool 62, a circumferential groove 66 a is formed on the inner periphery of the insertion hole 66, and a narrowing portion 67 is formed between both the circumferential grooves 62 a and 66 a. The opening of the throttle 67 increases as the speed increases and the spool 62 is displaced upward in the figure, and decreases as the speed decreases and the spool 62 is displaced downward.
[0037]
A communication channel 58 that communicates the inner circumferential groove 66a of the insertion hole 66 and the second outlet port 61 is formed in the second valve housing 7 'radially outward of the spool 62, as shown in FIG. In addition, a ring-shaped seal member 98 a is disposed between the valve housing 7 and the second valve housing 7 ′ in order to prevent leakage of pressurized oil from the communication flow path 58.
A radial hole 62 c is formed in the spool 62 to communicate the circumferential groove 62 a on the outer periphery of the spool 62 and the through hole 62 d of the spool 62.
The through hole 62 d of the spool 62 communicates with the space below the spool 62 in the insertion hole 66.
A communication flow path 76 that communicates the space below the spool 62 and the first outlet port 36 is formed across the valve housing 7 and the second valve housing 7 ′ on the radially outer side of the spool 62. In order to prevent leakage of pressure oil from the communication flow path 76, as shown in FIG. 9, a ring-shaped seal member 98b is disposed between the valve housing 7 and the second valve housing 7 ′.
A portion of the communication flow path 76 formed in the valve housing 7 constitutes a connection port of the variable throttle valve 60 to the valve housing 7 together with the second outlet port 61.
As a result, the pressure oil supplied from the pump 70 is guided to the communication channel 58 from the inter-valve channel 27 and the second outlet port 61, and reaches the throttle unit 67 from the communication channel 58. To the tank 71 through the communication channel 76 and the first outlet port 36. The spool 62 is formed with a drain passage 62h parallel to the through hole 62d, and connects the upper space and the lower space of the spool 62.
[0038]
The maximum value of the opening degree of the throttle part 67 is the maximum value of the total opening degree of the throttle parts A ′, B ′, C ′, D ′ belonging to the second group (the relative rotation angle of both valve members 31, 32 is large). It is the maximum value in the characteristic that the opening degree becomes smaller, that is, the maximum value of the full opening degree of the throttle parts B ′ and C ′ at the right steering, and the full opening of the throttle parts A ′ and D ′ at the left steering. The maximum value of the degree is hereinafter referred to as “the maximum value of the total opening”, which is the same) or increased until the aperture function is not achieved. The minimum value of the opening degree of the throttle part 67 is the minimum value of the total opening degree of the throttle parts A ′, B ′, C ′, D ′ belonging to the second group (the relative rotation angle of both valve members 31, 32 is large). The minimum value in the characteristic that the opening becomes smaller, that is, the minimum value of the full opening of the throttle parts B ′ and C ′ during the right steering, and the full opening of the throttle parts A ′ and D ′ during the left steering. This is the minimum value of the degree and includes the fully closed state.
[0039]
As a result, the hydraulic circuit shown in FIG. 2 is configured, and the opening of the oil passage between the throttle portions A ′, B ′, C ′, D ′ belonging to the second group and the tank 71 corresponds to the vehicle speed. This is changed by the operation of the variable throttle valve 60. That is, the pressure controlled by the throttle parts A ′, B ′, C ′, D ′ belonging to the second group of the pressure oil flow rate controlled by the throttle parts A, B, C, D belonging to the first group. The ratio to the oil flow rate is changed by the operation of the variable throttle valve 60.
[0040]
In FIG. 7, a solid line X indicates a change characteristic of the opening degree of the throttle portions A, B, C, and D belonging to the first group with respect to the relative rotation angle of both the valve members 31 and 32. An alternate long and short dash line U indicates a change characteristic of the opening degree of the throttle portions B ′ and D ′ between the communication concave portion 50c and the second pressure oil discharge concave portion 51c belonging to the second group with respect to the relative rotation angle. An alternate long and short dash line V indicates a change characteristic of the opening degree of the throttle portions A ′ and C ′ between the pressure oil supply concave portion 51a and the communication concave portion 50c belonging to the second group with respect to the relative rotation angle. A solid line Y indicates a combined change characteristic of the opening degrees of all the throttle portions A ′, B ′, C ′, and D ′ belonging to the second set with respect to the relative rotation angle. A broken line R indicates the opening degree of the variable throttle valve itself set by the variable throttle valve 60 at the middle speed travel of the throttle portions 67a and 67b.
[0041]
According to the first power steering device 1, when traveling at a low speed, the spool 62 is displaced downward in FIGS. 1 and 8, and the throttle portion 67 of the variable throttle valve 60 is fully closed by the displacement of the spool 62. become. Therefore, the hydraulic pressure acting on the hydraulic cylinder 20 is controlled according to the change characteristic line X of the opening degree of the first set of throttle portions A, B, C, and D. In this case, as shown by a one-dot chain line in FIG. 6, even if the steering input torque is small and the relative rotation angles of both valve members 31 and 32 are small, the throttle portions A, B, C, and D belonging to the first group It is possible to reduce the opening degree and increase the rate of increase of the hydraulic pressure that generates the steering assist force, thereby satisfying the high responsiveness of the steering at low speed traveling.
[0042]
During high speed travel, the spool 62 is displaced upward in FIGS. 1 and 8, and due to the displacement of the spool 62, the opening degree of the throttle portion 67 of the variable throttle valve 60 becomes the throttle portion A ′, which belongs to the second group. It becomes equal to or greater than the maximum value of the total opening of B ', C', D '. Therefore, the hydraulic pressure acting on the hydraulic cylinder 20 is the change characteristic line Y of the opening of the second set of throttle portions A ′, B ′, C ′, D ′ and the first set of throttle portions A, B, C. , D is controlled in accordance with the composite characteristic of the change characteristic line X of the opening degree. In this case, as shown by the solid line in FIG. 6, unless the steering input torque is increased and the relative rotational angles of the valve members 31 and 32 are increased, the throttle portions A ′, B ′, and C ′ belonging to the second group. The opening degree of D ′ is kept large without decreasing, and the rate of increase of the hydraulic pressure that generates the steering assist force is small, so that it is possible to satisfy the stability of steering during high-speed traveling.
[0043]
During medium speed travel, the opening of the throttle portion 67 of the variable throttle valve 60 due to the displacement of the spool 62 is the minimum value of the total apertures of the throttle portions A ′, B ′, C ′, D ′ belonging to the second group. Greater than and less than the maximum value. As a result, as shown in FIG. 7, until the throttle portions A, B, C, D belonging to the first group reach the minimum value (in the present embodiment, the fully closed state) (in FIG. Until the relative rotation angle becomes θa), the opening characteristic line R of the throttle 67 is combined with the change characteristic line X of the full opening of the throttles A, B, C, D belonging to the first set. A steering assist force according to the characteristic is applied. From the time when the throttle parts A, B, C, D belonging to the first group are fully closed, the total opening degree of the throttle parts A ', B', C ', D' belonging to the second group is variable. Until the opening degree of the throttle part 67 of the valve 60 becomes smaller (in FIG. 7, the relative rotation angle of both valve members is between θa and θb), the steering assist force is constant depending on the opening degree of the throttle part 67. Value. Thereafter, when the total opening degree of the throttle parts A ′, B ′, C ′, D ′ belonging to the second group becomes smaller than the opening degree of the throttle part 67 of the variable throttle valve 60, the throttle parts belonging to the second group. A steering assist force is applied according to the change characteristic line Y of all opening degrees of A ′, B ′, C ′, and D ′.
[0044]
After the throttle parts A, B, C, D belonging to the first group are fully closed, the total opening degree of the throttle parts A ′, B ′, C ′, D ′ belonging to the second group is variable. Until the opening degree of the throttle part 67 of the valve 60 becomes smaller (between θa and θb), the throttle parts A ′, B ′, C ′, D ′ belonging to the second group are fully closed. And the difference (θc−θa) between the apertures A, B, C, and D belonging to the first group being in the fully closed state is reduced without reducing. That is, suppose that the throttle portions A 'and C' between the pressure oil supply recess 51a and the communication recess 50c belonging to the second set are between the communication recess 50c and the second pressure oil discharge recess 51c. As with the throttle portions B ′ and D ′, all the throttle portions A ′ belonging to the second set with respect to the relative rotation angle are assumed to have an opening change characteristic with respect to the relative rotation angle indicated by a one-dot chain line U in the figure. The combined change characteristics of all the opening amounts of B ′, C ′, and D ′ are shown by a two-dot chain line M in FIG. Then, until the opening degree of the throttle parts A ′, B ′, C ′, D ′ belonging to the second group becomes smaller than the opening degree of the throttle parts 67a, 67b of the variable throttle valve 60 (both Since the relative rotation angle of the valve member becomes large (between θa and θd), the region L in which the steering assist force cannot be controlled according to the steering resistance increases as shown by the two-dot chain line in FIG. On the other hand, in the above-described embodiment, the closing angle θs of the throttle portions A ′ and C ′ between the pressure oil supply concave portion 51a and the communication concave portion 50c belonging to the second group is equal to that of the communication concave portion 50c. Since it is smaller than the closing angle θr of the throttle portions B ′ and D ′ between the pressure oil discharge recess 51c, the region in which the steering assist force cannot be controlled according to the steering resistance during medium speed traveling can be reduced. In addition, at the point where the throttle portions A ′ and C ′ between the pressure oil supply recess 51a and the communication recess 50c are fully closed (the relative rotation angle of both valve members in FIG. 7 is θe), contact is made. Since the throttle portions B ′ and D ′ between the concave portion 50c for use in pressure and the concave portion 51c for discharging the second pressure oil are not closed yet, the region in which the steering assist force can be controlled according to the steering resistance is not reduced.
[0045]
FIGS. 10 and 11 show a second rack and pinion type hydraulic power steering apparatus (one type of rack and pinion type hydraulic power steering apparatus) 101. In FIGS. 10 and 11, the part corresponding to the first power steering device 1 is indicated by adding 100 to the drawing code number of the first power steering device 1.
The difference between the second power steering device 101 and the first power steering device 1 is that a chamfered portion of an edge (encircled in FIG. 11) along the axial direction of the concave portion formed in the second valve member 132 is first. Are equal to each other, so that the hydraulic pressure change ratio with respect to the change of the steering resistance in each of the throttle portions A, A ′, B, B ′, C, C ′, D, and D ′ of the control valve 130 is equal. The closing angles of the respective throttle portions A, A ′, B, B ′, C, C ′, D, and D ′ are the same.
Further, the axial dimension of the first valve member 131 in the second power steering apparatus 101 is shorter than the axial dimension of the first valve member 31 in the first power steering apparatus 1.
Further, the variable throttle valve 60, the second outlet port 61, the flow path 59, the second pressure oil discharge recess 51c, and the communication flow path 76 in the first power steering device 1 are not provided, and the second pressure oil discharge The recess 151c corresponding to the recess 51c is connected to the input shaft 102 and the torsion from the flow path 152a formed in the input shaft 102, similarly to the recess 151b corresponding to the first pressure oil discharging recess 51b in the first power steering device 1. The first outlet port 136 is connected to the tank 171 via the bar 106.
The other configuration is the same as that of the first power steering apparatus 1, whereby the second power steering apparatus 101 can apply the steering assist force according to the steering resistance and the steering direction in the first rack and pinion type. Although it is the same as that of the hydraulic power steering apparatus 1, there is no additional function for changing the steering assist force in accordance with driving conditions such as the vehicle speed.
[0046]
When the first power steering device 1 and the second power steering device 101 are manufactured, as shown in FIGS. 1 and 10, from the center of meshing with the rack 16 of the pinion 15 in the first power steering device 1. , The axial dimensions a, b, c, d to the inlet port 34, the first port 37, the second port 38, and the first outlet port 36, and the engagement of the rack 116 of the pinion 115 in the second power steering device 101 The axial dimensions a, b, c, d from the center to the inlet port 134, the first port 137, the second port 138, and the first outlet port 136 are made equal. Further, the arrangement of piping 91, 92, 93, 94 connecting the control valve 30 in the first power steering device 1 to the pump 70, the hydraulic cylinder 20 and the tank 71, and the control valve 130 in the second power steering device 101. The pipes 191, 192, 193, 194 connected to the pump 170, the actuator 120, and the tank 171 are made equal to each other.
[0047]
According to the first embodiment, the first power steering device 1 and the second power steering device 101 are connected to the inlet ports 34, 134, the first from the center of engagement with the racks 16, 116 of the pinions 15, 115. The axial dimensions a, b, c, d to the ports 37, 137, the second ports 38, 138 and the first outlet ports 36, 136 are the same, and the second valve housing 7 'of the variable throttle valve 60 is Since the first power steering device 1 and the second power steering device 101 are separate from the valve housing 7 of the first power steering device, the shape of the valve housings 7 and 107 can be prevented from being different. Accordingly, the seat surface 7b and the bolt hole for attaching the second valve housing 7 'of the variable throttle valve 60 to the valve housing 107 of the second power steering device 101 as the valve housing 7 of the first power steering device 1 are provided. It is possible to use the one formed with the second outlet port 61 for connection between the control valve 30 and the variable throttle valve 60 and the communication flow path 76, and the output shafts 3, 103 and the torsion. The same bars 6 and 106 can be used for the first power steering apparatus 1 and the second power steering apparatus 101.
[0048]
Further, the first outlet ports 36 and 136 in the first and second power steering devices 1 and 101 are valve housing internal spaces 7a and 107a that are axially separated from the pinions 15 and 115 more than the first valve members 31 and 131, respectively. The first valve members 31 and 131 are arranged in the axial direction away from the pinions 15 and 115 so as to communicate with the control valves 30 and 130 via the. Therefore, the axial dimension of the first valve member 31 of the first power steering device 1 ensures that the oil flow path 59 for connection to the variable throttle valve 60 is sufficient for the second power steering device 101. Even if it is longer than the axial dimension of the first valve member 131, the axial dimension of the elongated part is smaller than the axial dimension of the internal space 107 a of the valve housing 107 of the second power steering device 101. Thus, the first valve member 31 can be disposed in the internal space 7a of the valve housing 7 having the same axial dimension as the valve housing 107 of the second power steering apparatus 101. As a result, the valve housing 107 of the second power steering device 101 that has been conventionally used can be used as the valve housing 7 of the first power steering device 1.
[0049]
In addition, according to the first power steering device 1, the second outlet port 61 for connecting the control valve 30 and the variable throttle valve 60, and the first outlet port for connecting the control valve 30 and the tank 71. Since the distance to 36 is shorter than in the prior art, the oil flow paths 58 and 76 between the variable throttle valve 60 and the control valve 30 can be shortened. Thereby, 2nd valve housing 7 'can be reduced in size.
[0050]
Further, the variable throttle valve 60 changes the opening degree of its throttle part 67 by the axial movement of the spool 62, and includes a plane including the axis of the spool 62 and a plane including the relative rotational axes of the valve members 31 and 32. Are parallel to each other, and oil flow paths 58 and 76 between the variable throttle valve 60 and the control valve 30 are provided in the second valve housing 7 'outside the spool 62 in the radial direction. The flow paths 58 and 76 can be shortened as much as possible, and the dimension of the second valve housing 7 ′ in the relative rotational axis direction of the valve members 31 and 32 can be made as small as possible. Thereby, size reduction and weight reduction of an apparatus can be achieved.
[0051]
Furthermore, since the dimension of the second valve housing 7 ′ in the relative rotational axis direction of the valve members 31 and 32 can be made as small as possible, the first rack and pinion hydraulic power steering device 1 of the second embodiment of FIG. ′, The shaft center of the spool 62 is made non-parallel to the relative rotation shafts of the valve members 31 and 32 to prevent interference between the variable throttle valve 60 and other parts. Can be easily placed in places where space is limited. Others are the same as in the first embodiment, and the same parts are denoted by the same reference numerals. In the example shown in FIG. 12, the axial direction of the spool 62 is perpendicular to the relative rotational axis direction of the valve members 31 and 32, but is not limited to a right angle, depending on the relationship with other surrounding components. The direction should be.
[0052]
FIG. 13 shows a second rack and pinion type hydraulic power steering apparatus 101 ′ of the third embodiment. This steering device 101 'removes the variable throttle valve 60 from the valve housing 7 of the first rack and pinion hydraulic power steering device 1 of the first embodiment, and instead attaches and removes the closing member 201 to the valve housing 7 with bolts or the like. It is configured by attaching it as possible.
An opening formed in the valve housing 7, and a second outlet port 61 used as a connection port with the variable throttle valve 60 and a communication flow path 76 in the first rack and pinion hydraulic power steering device 1. , And is closed by the closing member 201.
Others are the same as those of the first rack and pinion type hydraulic power steering apparatus 1 of the first embodiment, and the same portions are denoted by the same reference numerals.
As a result, the second rack and pinion hydraulic power steering device 101 ′ of the third embodiment is configured as all components including the valve housing 7 and the valve members 31 and 32 except for the closing member 201. A device capable of configuring the first rack and pinion hydraulic power steering device 1 of the embodiment is used.
[0053]
According to the second rack and pinion hydraulic power steering device 101 ′ of the third embodiment, the same components as the first rack and pinion hydraulic power steering device 1 of the first embodiment can be used to reduce the cost. Can be planned. Furthermore, by attaching the variable throttle valve 60 to the valve housing 7 in place of the closing member 201, the first rack and pinion hydraulic power steering device 1 can be obtained.
[0054]
FIG. 14 shows a first rack and pinion type hydraulic power steering apparatus 1 ″ of the fourth embodiment, and FIG. 15 shows a second rack and pinion type hydraulic power steering apparatus 101 ″ of the fourth embodiment.
The variable throttle valve 60 ″ of the first rack and pinion hydraulic power steering apparatus 1 ″ of the fourth embodiment and the variable throttle valve 60 of the first rack and pinion hydraulic power steering apparatus 1 of the first embodiment are described. When the moving direction of the spool 62 is the vertical direction, the spool 62 is mounted on the valve housing 7 upside down.
The second rack and pinion hydraulic power steering device 101 ″ of the fourth embodiment removes the variable throttle valve 60 ″ from the valve housing 7 of the first rack and pinion hydraulic power steering device 1 ″ of the fourth embodiment, Instead, the closing member 201 ″ is detachably attached to the valve housing 7 with a bolt or the like. Seal members 202 "and 203" are interposed between the closing member 201 "and the valve housing 7 in order to prevent pressure oil from leaking from the second outlet port 61" and the communication flow path 76 ". Others are the same as in the first embodiment, and the same parts are denoted by the same reference numerals.
According to the fourth embodiment, the same operational effects as those of the first embodiment can be obtained. Further, according to the second rack and pinion type hydraulic power steering device 101 ″ of the fourth embodiment, the third embodiment can be achieved. The same effects as the second rack and pinion type hydraulic power steering apparatus 101 ′ can be obtained.
[0055]
【The invention's effect】
According to the method of the present invention, it is possible to reduce costs by sharing parts between a normal type rack and pinion type hydraulic power steering device and a type of rack and pinion type hydraulic power steering device having an additional function. Costs can be reduced by using common hydraulic piping and common control valve components. Further, it is possible to easily change a normal type rack and pinion type hydraulic power steering apparatus to a type of rack and pinion type hydraulic power steering apparatus having an additional function. According to the first invention device of the present invention, it is possible to easily process an oil flow path in a rack and pinion type hydraulic power steering device having an additional function, to reduce the size and weight of the device, and to limit the space. Can be easily placed in any place. According to the second invention device of the present invention, it is possible to provide a normal type rack and pinion type hydraulic power steering device that can be easily changed to a type of rack and pinion type hydraulic power steering device having an additional function.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view of a first hydraulic power steering apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a hydraulic circuit of the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 3 is an explanatory diagram of a cross-sectional structure of a control valve in the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 4 is an exploded view of a control valve of the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 5 is an enlarged view of a main part of a control valve of the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 6 is a diagram showing the relationship between input torque and hydraulic pressure and the relationship between the relative rotation angle of both valve members and hydraulic pressure in the first hydraulic power steering apparatus of the first embodiment of the present invention.
FIG. 7 is a diagram showing the relationship between the opening degree of the throttle portion of the control valve and the relative rotation angle of the valve member in the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 8 is a longitudinal sectional view of a variable throttle valve of the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 9 is a cross-sectional view of the valve housing and the variable throttle valve housing of the first hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 10 is a longitudinal sectional view of a second hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 11 is an explanatory diagram of a cross-sectional structure of a control valve in the second hydraulic power steering apparatus according to the first embodiment of the present invention.
FIG. 12 is a longitudinal sectional view of a first hydraulic power steering apparatus according to a second embodiment of the present invention.
FIG. 13 is a longitudinal sectional view of a second hydraulic power steering apparatus according to a third embodiment of the present invention.
FIG. 14 is a longitudinal sectional view of a first hydraulic power steering apparatus according to a fourth embodiment of the present invention.
FIG. 15 is a longitudinal sectional view of a second hydraulic power steering apparatus according to a fourth embodiment of the present invention.
[Explanation of symbols]
1, 1 ′, 1 ″ first hydraulic power steering device (the other type of hydraulic power steering device)
3, 103 Output shaft
7, 107 Valve housing
7a, 107a Valve housing internal space
7 'Second valve housing
15,115 pinion
20, 120 Hydraulic cylinder
30, 130 Control valve
31, 131 First valve member
32, 132 Second valve member
34 Inlet port
36 1st exit port
37 1st port
38 2nd port
60 Variable throttle valve
61, 61 ″ second outlet port
70, 170 pump
71,171 tanks
76, 76 ″ communication channel
91, 92, 93, 94, 191, 192, 193, 194 Piping
101, 101 ′, 101 ″ second hydraulic power steering device (one type of hydraulic power steering device)
201, 201 ″ closure member
A, A ', B, B', C, C ', D, D'

Claims

A method of manufacturing two types of rack and pinion type hydraulic power steering devices (1, 1 ′, 1 ″, 101, 101 ′, 101 ″) ,
Each type of steering apparatus (1, 1 ', 1', 101, 101 ', 101 "), respectively, a hydraulic actuator (20, 120) for generating steering assist power, hydraulic pressure acting on the actuator (20, 120) Control valves (30, 130) ,
Wherein the control valve (30, 130) includes a valve housing (7, 107), and relatively rotatably inserted the cylindrical first valve member (31, 131) in said valve housing (7, 107), wherein a second valve member (32, 132) which is relatively rotatably inserted on the steering resistance in the first valve member (31, 131), the relative rotation angle between the two valve members (31,131,32,132) And having a plurality of throttle portions whose opening degree changes in response,
Wherein the first output shaft which is connected to rotate together the valve member (31, 131) (3,103) pinions (15, 115) is formed, the steering and the steering direction by a change in the opening degree of each throttle portion as the steering assisting force corresponding to the resistance can be imparted, the control valve (30, 130) a pump (70, 170), said actuator (20, 120) and a tank (71, 171) for piping connections to each connection port (34,36,37,38,134,136,137,138) is provided in the valve housing (7, 107),
One type of steering apparatus (101, 101 ', 101 ") the hydraulic change rate with respect to the change in the steering resistance in each of the diaphragm portions of the phase equal,
Other types of steering apparatus (1, 1 ', 1 ") each diaphragm unit first set and the second set and two sets grouping, wherein the first set belonging to the diaphragm portion and the second of the stop unit belonging to the set pressure change rate is large with respect to the change of the steering resistance, pressure controlled by the throttle portion belonging to the second set of hydraulic fluid flow rate controlled by the throttle portion belonging to said first set as can be changed ratio oil flow, the oil passage between said throttle portion belonging to a second set tank (71), to vary the degree of opening of its throttle section according to the operating conditions In the case where a variable throttle valve (60, 60 ″) is provided,
One type of steering apparatus (101, 101 ', 101 ") and an axial dimension from said pinion (115) of said to each connecting port (134,136,137,138) in the other type of steering device (1 , 1 ', 1 ") the phase-equalizing the axial dimension to each connection port (34,36,37,38) from said pinion (15) in,
The variable throttle valve (60, 60 ') of the housing (7') the other type of steering device (1, 1 ', 1 ") wherein a separate body from the valve housing (7) of,
The connection ports (36, 136) to the tanks (71, 171) in the steering devices (1, 1 ′, 1 ″, 101, 101 ′, 101 ″) of each type are connected to the first valve members (31, 31). 131) through the internal space (7a, 107a) of the valve housing (7, 107) that is axially separated from the pinion (15, 115) than the control valve (30, 130). The first valve member (31, 131) is arranged farther away from the pinion (15, 115) in the axial direction than the first valve member (31, 131), and the first valve member (31 in the other type of steering device (1, 1 ′, 1 ″). ) Is longer than the axial dimension of the first valve member (131) in one type of steering device (101, 101 ', 101 "),
Connection port (61, 61 ″) between the control valve (30) and the variable throttle valve (60, 60 ″) in the valve housing (7) of the other type of steering device (1, 1 ′, 1 ″) Is disposed axially away from the pinion (15) than the connection ports (34, 37, 38, 134, 137, 138) to the pump (70) and the actuator (20). Manufacturing method of rack and pinion type hydraulic power steering apparatus.

A method of manufacturing two types of rack and pinion type hydraulic power steering devices (1, 1 ″, 101 ′, 101 ″),
Each type of steering apparatus (1, 1 ', 101', 101 "), respectively, a hydraulic actuator (20, 120) for generating steering assist power, hydraulic pressure control valve to act on the actuator (20, 120) ( 30, 130),
The control valves (30, 130) include a valve housing (7, 107), a cylindrical first valve member (31, 131) inserted into the valve housing (7, 107) so as to be relatively rotatable, A relative rotation angle between the second valve member (32, 132) inserted into the first valve member (31, 131) so as to be relatively rotatable in accordance with the steering resistance and the two valve members (31, 131, 32, 132). And having a plurality of throttle portions whose opening degree changes in response,
Pinions (15, 115) are formed on the output shafts (3, 103) connected to the first valve members (31, 131) so as to rotate along with the first valve members (31, 131). For connecting the control valves (30, 130) to the pumps (70, 170), the actuators (20, 120) and the tanks (71, 171) so that a steering assist force according to the resistance can be applied. Connection ports (34, 36, 37, 38, 134, 136, 137, 138) are provided in the valve housing (7, 107),
The rate of change in hydraulic pressure with respect to the change in steering resistance in each of the throttle portions of one type of steering device (101 ′, 101 ″) is equalized,
The respective throttle portions of the other type of steering device (1, 1 ″) are divided into a first group and a second group, and the throttle units belonging to the first group belong to the second group. The hydraulic pressure change ratio with respect to the change in steering resistance is larger than that of the throttle unit, and the pressure oil flow rate controlled by the throttle unit belonging to the first group is larger than the pressure oil flow rate controlled by the throttle unit belonging to the second group. A variable throttle valve that changes the opening of its throttle part in accordance with operating conditions in the oil passage between the throttle part belonging to the second group and the tank (71) so that the ratio can be changed. (60, 60 ″) are provided,
The axial dimension from the pinion (115) to the connection ports (134, 136, 137, 138) in one type of steering device (101 ′, 101 ″) and the other type of steering device (1, 1, ″) And the axial dimensions from the pinion (15) to the connection ports (34, 36, 37, 38) are equalized,
The housing (7 ′) of the variable throttle valve (60, 60 ″) is separated from the valve housing (7) of the other type of steering device (1, 1 ″),
The variable throttle valve (60, 60 ″) can be attached to and detached from the valve housing (7) of the other type of steering device (1, 1 ″),
The control valve (30) of the steering device (1, 1 ″) of the other type is used as the valve housing (107) and the valve members (131, 132) of the steering device (101 ′, 101 ″) of one type. ) Which can constitute the valve housing (7) and the valve members (31, 32),
An opening of a valve housing (107) constituting a control valve (130) of one type of steering device (101 ′, 101 ″), and this valve housing (107) is the other type of steering device (1, 1, 1). If the control valve (30) of "") is configured, the detachable closing member (201, 201 ") used as the connection port (61, 61") with the variable throttle valve (60, 60 ") The rack-and-pinion type hydraulic power steering device is closed by

One type of steering apparatus (101, 101 ', 101 ") pipe connecting the control valve (130) to said pump (70, 170) said actuator (120) wherein a tank (171) in (191, 192,193,194) and placement, other types of steering apparatus (1, 1 ', 1 "the control valve in) (the actuator 30) and the pump (70) (20) and said tank (71) The manufacturing method of the rack and pinion type hydraulic power steering device according to claim 1 or 2, wherein the arrangement of pipes (91, 92, 93, 94) connected to each other is equal.

A steering assist force generating hydraulic actuator (20), and a hydraulic control valve (30) acting on the actuator (20),
The control valve (30) includes a valve housing (7), a cylindrical first valve member (31) inserted into the valve housing (7) so as to be relatively rotatable, and the first valve member (31). A second valve member (32) inserted so as to be relatively rotatable according to the steering resistance, and a plurality of throttle portions whose opening degree changes according to the relative rotation angle of the both valve members (31, 32),
A pinion (15) is formed on the output shaft (3) connected to the first valve member (31) so as to rotate along with the first valve member (31). Connection ports (34, 36, 37, 38) for pipe connection between the control valve (30) and the pump (70), the actuator (20), and the tank (71) are provided so that force can be applied. Provided in the valve housing (7), each throttle part is divided into a first group and a second group, and the throttle part belonging to the first group is more than the throttle part belonging to the second group. The hydraulic pressure change ratio with respect to the change in steering resistance is increased, and the ratio of the pressure oil flow rate controlled by the throttle unit belonging to the first group to the pressure oil flow rate controlled by the throttle unit belonging to the second group is changed. Can As described above, the variable throttle valve (60, 60 ″) for changing the opening degree of the throttle unit according to the operating condition in the oil passage between the throttle unit belonging to the second group and the tank (71). In the hydraulic power steering apparatus (1, 1 ′, 1 ″) provided with the valve housing (7) and the housing (7 ′) of the variable throttle valve (60, 60 ″) are separated from each other,
The connection port (36) between the control valve (30) and the tank (71) is connected to the valve housing (7) which is axially separated from the pinion (15) than the first valve member (31). The first valve member (31) is arranged more axially away from the pinion (15) so as to communicate with the control valve (30) through an internal space (7a),
The connection port (61, 61 ″) between the control valve (30) and the variable throttle valve (60, 60 ″) is connected to the control valve (30), the pump (70) and the actuator (20). Arranged more axially away from the pinion (15) than the connection port (34, 37, 38),
The variable throttle valve (60, 60 ″) changes the opening of its throttle part by the axial movement of the spool (62), and includes a plane including the axis of the spool (62) and the two valve members (31). 32) is parallel to the plane including the relative rotational axis, and the control valve (30) is provided in the housing (7 ') of the variable throttle valve (60, 60 ") radially outward of the spool (62). ) And the variable throttle valve (60, 60 ″), a rack and pinion type hydraulic power steering apparatus is provided.

The rack and pinion type hydraulic power steering apparatus according to claim 4, wherein the shaft center of the spool (62) and the relative rotation shaft of the valve members (31, 32) are non-parallel .

A steering assist force generating hydraulic actuator (20), and a hydraulic control valve (30) acting on the actuator (20),
The control valve (30) includes a valve housing (7), a cylindrical first valve member (31) inserted into the valve housing (7) so as to be relatively rotatable, and the first valve member (31). A second valve member (32) inserted so as to be relatively rotatable according to the steering resistance, and a plurality of throttle portions whose opening degree changes according to the relative rotation angle of the both valve members (31, 32),
A pinion (15) is formed on the output shaft (3) connected to the first valve member (31) so as to rotate along with the first valve member (31), and the steering assist according to the steering direction and the steering resistance by the change in the opening of each throttle part. Connection ports (34, 36, 37, 38) for pipe connection of the control valve (30) to the pump (70), the actuator (20) and the tank (71) are provided so that force can be applied. In the hydraulic power steering device (1, 1 ′, 1 ″) provided in the housing (7),
An opening is formed in the valve housing (7);
The plurality of throttle portions are grouped into a first group and a second group,
If the opening is closed, the hydraulic pressure change ratio with respect to the change in the steering resistance in each of the first group of throttle parts is equalized, and the flow of pressure oil in each of the second group of throttle parts is prevented. And
As a connection port the opening (61, 61 '), wherein the valve housing (7), in the oil passage between said throttle portion belonging to a second set tank (71), itself depending on the operating conditions The variable throttle valve (60, 60 ″) for changing the opening of the throttle unit is detachable,
The oil passage between the throttle part belonging to the second group and the tank (71) is opened via the variable throttle valve (60, 60 ″), so that the throttle part belonging to the first group The hydraulic pressure change rate with respect to the change in steering resistance is larger than the throttle part belonging to the second group,
The pressure controlled by the throttle part belonging to the second group of the pressure oil flow rate controlled by the throttle part belonging to the first group by the opening degree change of the throttle part of the variable throttle valve (60, 60 ″). A rack and pinion type hydraulic power steering apparatus characterized in that a ratio to an oil flow rate is changed .