JP3897423B2

JP3897423B2 - Mobile wheel braking release device for self-propelled work vehicles

Info

Publication number: JP3897423B2
Application number: JP30872197A
Authority: JP
Inventors: 健一速水; 雅明寿美田
Original assignee: Shinmaywa Industries Ltd
Current assignee: Shinmaywa Industries Ltd
Priority date: 1997-11-11
Filing date: 1997-11-11
Publication date: 2007-03-22
Anticipated expiration: 2017-11-11
Also published as: JPH11141587A

Abstract

PROBLEM TO BE SOLVED: To provide a moving wheel brake-releasing device whereby brake application to each moving wheel by a moving wheel braking device is released using a simple configuration without resorting to an electric control, misoperation due to failure, etc., is precluded, and enhancement of the safety and cost-down are accomplished. SOLUTION: A moving wheel 13 is installed at the bottom of each supporting leg capable of expanding and contracting intalled on the front left and right and the rear left and right of the chassis of a vehicle, and the front supporting leg is equipped with a hydraulic motor 9 to drive the respective front moving wheel when pressure oil is supplied, while the rear supporting leg is equipped with a moving wheel braking device 22 to apply brake to the respective rear moving wheel when pressure oil is supplied. Each moving wheel braking device is equipped with a brake cylinder 23 to apply brake to the rear moving wheel with the pressure oil supplied from a pressure oil supply pipe 25, a pressure oil exhaust pipe 27 which exhausts the pressure oil from the brake cylinder and disengages the brake application to the rear moving wheel, and a pilot check valve 29 which puts the pressure oil exhaust pipe in communication or shuts it from communication, and when the front moving wheels are driven by the hydraulic motors the pilot pressure is fed to the pilot check valve via the pilot pressure supply pipe 34 so that the pressure oil exhaust pipe is put in communication to make it possible that the pressure oil is exhausted, and thus brake application to the rear moving wheels is disengaged.

Description

【０００１】
【発明の属する技術分野】
本発明は、車台前後の左右一対の支持脚伸長時に車台を接地面に対して移動させる移動輪を備えた自走式作業車の移動輪制動解除装置に関し、詳しくは、移動輪の制動解除を確実かつ安価に行い得るようにする対策に係る。
【０００２】
【従来の技術】
従来、例えば、実開平５−７６９２９号公報に開示されるように、車台に対して起伏および伸縮自在にかつ旋回自在に設けられたブーム先端のバケットにより高所で作業を行う作業装置などを車台に装着した作業車などにおいては、前後左右輪の後方に、車台（作業車自体）を接地面に対して伸長時に支持する伸縮可能な都合４基の支持脚を設けるとともに、この各支持脚の下端に伸長時に車台を移動可能とする移動輪を設け、車台を支持脚により支持した状態で、移動輪の自走により高所での作業が連続的に行われるようにしている。
【０００３】
また、このような自走式作業車にあっては、前後の支持脚のうち前側の支持脚に、油圧アクチュエータなどの移動輪駆動手段が設けられていて、該移動輪駆動手段の作動によって上記前側の支持脚の移動輪を駆動させるようにしている。この場合、一般には、作業車の制動が後輪で行われる関係上、各支持脚の伸長時には、先に前側の支持脚を伸長させて前側移動輪を地面に接地させ、上記移動輪駆動手段不作動状態において、つまり前側移動輪の回転規制により制動を得た状態で、後側の支持脚を伸長させて前側移動輪を地面に接地させるようにしている。一方、各支持脚の収縮時には、先に後側の支持脚を収縮させて後輪を地面に接地させ、該後輪により制動を得た状態で、前側の支持脚を収縮させて前輪を地面に接地させるようにしている。
【０００４】
しかし、作業者が前後の支持脚の伸縮動作を誤って操作し、各支持脚の伸長時に先に後側の支持脚を伸長させて後側移動輪を地面に接地させたり、各支持脚の収縮時に先に前側の支持脚を収縮させて前輪を地面に接地させると、作業車が不用意に自走するといった問題がある。
【０００５】
そこで、このような作業者の誤操作を防止する上で、移動輪制動解除装置により移動輪の制動解除が行われるようにした自走式作業車も開発されている。この移動輪制動解除装置は、後側の支持脚に、その後側の支持脚の移動輪を制動させる移動輪制動手段を備え、作業者が誤って支持脚を伸縮動作しても、移動輪制動手段により後側の移動輪の制動力でもって作業車の不用意な自走が防止されるようになっている。この移動輪制動解除装置では、移動輪制動手段を、油圧の供給により後側の移動輪を制動する制動シリンダと、該制動シリンダへの油圧の給排を切換える電磁切換弁と、該電磁切換弁を切換制御する制御部とで構成していて、前後の支持脚が接地したことを検出する支持脚接地検出器からの信号、および支持脚がストロークエンドまで伸長したことを検出する支持脚ストローク検出器からの信号などが上記制御部に入力され、これらの信号に基づいて上記電磁切換弁を切換制御することで、上記制動シリンダに油圧を供給して後側の移動輪の制動を行う一方、上記制動シリンダから油圧を排出して後側の移動輪の制動解除を行うようにしている。
【０００６】
【発明が解決しようとする課題】
ところが、上述の如き移動輪制動手段の制動解除を電気的な制御により行うものでは、以下に述べるような欠点がある。
【０００７】
すなわち、移動輪制動手段は、電磁切換弁、支持脚接地検出器および支持脚ストローク検出器等の電気機器を備えているため、制動解除時の制御が複雑となり、故障等によって誤作動、例えば移動輪が地面に接地していない状態で移動輪の制動を誤って解除するなどの不具合を起こす可能性がある。また、このような電気機器が高価なものであるので、移動輪制動手段のコストアップを招くことになる。
【０００８】
本発明はかかる点に鑑みてなされたもので、その目的とするところは、移動輪制動手段による移動輪の制動解除が電気的な制御を行うことなく簡単な構成で行われるようにすることで、故障等による誤作動を防止して安全性の向上を図るとともに、移動輪制動手段のコストダウンを図ることにある。
【０００９】
【課題を解決するための手段】
上記目的を達成するため、請求項１記載の発明が講じた解決手段は、下端に移動輪を有する支持脚が車台の前後に左右一対ずつ伸縮自在に設けられ、該各支持脚の伸長時に上記各移動輪が接地することで上記車台が接地面に対して移動可能に支持されるように構成された自走式作業車の移動輪制動解除装置を前提とする。さらに、上記前後の支持脚のうち一方の支持脚に、その一方の支持脚の移動輪を流体の供給により駆動させる一方、流体の供給停止により駆動させないようにする移動輪駆動手段を設ける。また、他方の支持脚に、その他方の支持脚の移動輪を流体の供給により制動させる一方、流体の供給停止により制動解除する移動輪制動手段を設ける。そして、上記移動輪駆動手段による流体の供給が禁止されている場合に、上記移動輪制動手段による流体の供給を行って上記他方の支持脚の移動輪を制動させ、上記車台の移動を規制する。一方、上記移動輪駆動手段に流体の供給がなされている場合に、上記移動輪制動手段に流体の供給を禁止させて上記他方の支持脚の移動輪を制動解除し、上記車台を移動させるように、上記移動輪駆動手段に対する流体の供給又は供給の禁止のみで上記他方の支持脚の移動輪の制動解除又は制動が行われるような構成としたものである。
【００１０】
請求項２記載の発明が講じた解決手段は、請求項１記載の発明の移動輪駆動手段および移動輪制動手段を特定したことを特徴とする。具体的には、移動輪駆動手段に、一方の支持脚の移動輪を流体の供給により駆動させる流体圧モータを備える。一方、移動輪制動手段に、流体を供給する流体供給管と、該流体供給管を経て供給される流体により他方の支持脚の移動輪を制動させるよう伸長する伸縮自在な制動シリンダと、上記他方の支持脚の移動輪を制動解除するよう上記制動シリンダを収縮させて該制動シリンダから流体を排出する流体排出管と、該流体排出管に設けられ、この流体排出管を流体排出可能に連通または流体排出不能に遮蔽する連通遮蔽手段と、該連通遮蔽手段と上記流体圧モータとの間に連結され、上記流体排出管が流体排出可能に連通するよう上記一方の支持脚の移動輪駆動時に供給される流体圧モータからの流体を上記連通遮蔽手段に作用させる流体作用管とを備える構成としたものである。
【００１１】
これにより、請求項１および請求項２記載の発明では、前後一方の支持脚の移動輪を駆動させないよう流体圧モータなどの移動輪駆動手段に流体の供給が禁止されている場合には、移動輪制動手段による流体の供給により他方の支持脚の移動輪を制動、たとえば流体供給管を経て供給される流体により制動シリンダを伸長させて他方の支持脚の移動輪を制動させるようにしている。
【００１２】
一方、上記一方の支持脚の移動輪を駆動させるよう移動輪駆動手段（流体圧モータ）に流体の供給がなされている場合には、移動輪制動手段による流体の供給が禁止されて上記他方の支持脚の移動輪を制動解除、たとえば一方の支持脚の移動輪駆動時に供給される流体圧モータからの流体を流体作用管を経て流体排出管途中の連通遮蔽手段に作用させて上記流体排出管を流体排出可能に連通させることで、制動シリンダからの流体を流体排出管を経て排出して制動シリンダを収縮させ、該制動シリンダによる他方の支持脚の移動輪を制動解除させるようにしている。
【００１３】
これにより、移動輪駆動手段および移動輪制動手段への流体給排管などの流体の流通系路のみで移動輪制動手段の制動解除が簡単に行え、複雑な電気的な制御による移動輪の制動解除を廃止して、電磁切換弁、支持脚接地検出器および支持脚ストローク検出器等の電気機器を不要にし、電気機器の故障等による誤作動、例えば移動輪が地面に接地していない状態で移動輪の制動を誤って解除するなどの誤作動が防止される上、作業者が前後の支持脚の操作順位を間違って操作しても移動輪による制動が確実に得られ、安全性が高められる。しかも、移動輪制動手段の制動解除が制動シリンダ、流体供給管、流体排出管、連通遮蔽手段および流体作用管により行われ、高価な電気機器が不要となり、コストが低廉化する。
【００１４】
さらに、請求項３記載の発明が講じた解決手段は、請求項１記載の発明の移動輪駆動手段および移動輪制動手段を特定したことを特徴とする。具体的には、移動輪駆動手段に、一方の支持脚の移動輪を流体の供給により駆動させる流体圧モータを備える。一方、移動輪制動手段に、流体を給排する流体給排管と、他方の支持脚の移動輪を制動させるよう上記流体給排管を経て給排される流体により伸長する制動シリンダと、上記流体給排管に介設され、上記他方の支持脚の移動輪を制動解除するよう上記流体給排管を経て給排される流体により上記制動シリンダを収縮させて該流体給排管の給排方向を切換える切換弁と、該切換弁と上記流体圧モータとの間に連結され、上記流体給排管の給排方向が切換わるよう上記一方の支持脚の移動輪駆動時に供給される流体圧モータからの流体を上記切換弁に作用させる流体作用管とを備える構成としたものである。
【００１５】
これにより、請求項３記載の発明では、流体給排管に介設された切換弁は、移動輪駆動手段（流体圧モータ）により一方の支持脚の移動輪を駆動させる際にその移動輪駆動手段から流体作用管を経て供給される流体により切換えられ、流体給排管内の流体の給排方向を逆転させて他方の支持脚の移動輪を制動解除するようにしているので、構造がシンプルでかつ安価な切換弁によって移動輪制動手段の制動解除が行われ、さらなる安全性の向上およびコストダウンが達成される。
【００１６】
【発明の実施の形態】
以下、本発明の実施の形態を図面に基づいて説明する。
【００１７】
図４は、本発明の第１の実施形態に係る移動輪制動解除装置を備えた自走式作業車を示し、１は車体、２はこの車体１に起伏、旋回可能に設置された作業装置としてのブーム、１は高所作業時に上記車体１を浮上状態でかつ移動可能に支持する支持脚である。
【００１８】
上記車体１は車台１ｃと、該車台１ｃ上に設けられた荷台１ａと、上記車台１ｃに一体的に連結された車室部１ｂとからなり、この車体１は前後に一対ずつの４つの走行用車輪４ａ，４ｂの駆動により通常時の走行が行われ、前輪４ａが通常走行時の車輪になる。この場合、車体１を停車した状態でパーキングブレーキ（図示せず）を操作すると、後輪４ｂによる制動が得られるようになっている。
【００１９】
また、上記ブーム２は、上記車台１ｃに垂直軸Ｖ1 回りに回転可能に支持された旋回支柱２ａと、この旋回支柱２ａの上端に水平軸Ｈ1 回りに回転可能に連結されるとともに、起伏用シリンダ２ｂにより起伏可能に連結された伸縮管２ｃと、この伸縮管２ｃの先端に設けられた作業用バケット２ｄとからなり、上記バケット２ｄに作業者が乗って上記起伏用シリンダ２ｂを伸長作動させることにより、そのバケット２ｄが上記車台１ｃに対して相対的に上昇するようになっている。
【００２０】
上記支持脚３は、車台１ｃ前側に設けられた左右一対の前側支持脚３ａ（一方の支持脚）と、車台１ｃ後側に設けられた左右一対の後側支持脚３ｂ（他方の支持脚）とからなる。
【００２１】
上記各前側支持脚３ａ（同一構成となるので、図３に示す左側のものについてのみ符号を付し、右側のものについては括弧内に相違する符号のみを付してその説明を省略する）は、図３に左側のものについて詳しく示すように、ジャッキ部５を備えている。このジャッキ部５の下端にはブラケット６が垂直軸Ｖ2 回りに回転可能に保持され、該ブラケット６は油圧シリンダ７Ｌ（７Ｒ）により回転作動するようになっている。上記ブラケット６には前側移動輪８が水平軸Ｈ2 回りに回転可能に保持され、この前側移動輪８が高所作業時の舵取り車輪として構成されている。また、上記ブラケット６には、上記前側移動輪８を回転駆動させる移動輪駆動手段としての油圧モータ９（流体圧モータ）が取付けられている。そして、上記前側移動輪８は、油圧モータ９の非駆動時に回転規制されて制動を得た状態となっている。また、上記前側移動輪８は、中実のゴムタイヤにより形成されて、パンクの発生による車体１の傾動が生じないようにされている。なお、図３および図４には左側の前側支持脚３ａのみを示すが、右側のものも上記左側のそれと同様に構成されている。
【００２２】
上記各ジャッキ部５は、上記車台１ｃに対して上下方向に配され、有底角筒状の外筒５ａが前方に向かって下り勾配になるように傾斜させた傾斜軸Ｘ1 を有して上記車台１ｃに固定されている。この外筒５ａ内には角筒状の内筒５ｂが摺動可能に挿入されている。上記内筒５ｂ内には、一端が内筒５ｂの下端に、他端が上記外筒５ａの上端にそれぞれ連結されたシリンダ５ｃが収容されている。上記内筒５ｂの下端には、上記ブラケット６を保持するボス部５ｄが固定されている。上記ブラケット６には、図示しないが、前側移動輪８のホイールのリムより内方（水平軸Ｈ2 方向）へ膨出するディスクがベアリングを介して回転自在に支持されている。そして、この各ジャッキ部５では、上記シリンダ５ｃの伸長作動により上記内筒５ｂが外筒５ａから突出し前側移動輪８が斜め下方に押し下げられて車体１を浮上させた浮上状態（図３及び図４に一点鎖線で示す状態）にされ、縮小作動により上記内筒５ｂが上記外筒５ａ内に没入して走行用車輪４ａ，４ｂが接地した収納状態（同図に実線で示す状態）にされるようになっている。
【００２３】
上記各ブラケット６は上記各前側移動輪８の接地部分を残して上部を覆うカバー６ａと、このカバー６ａの上面から上方に突出する軸部６ｂとからなり、この軸部６ｂが上記ボス部５ｄにより垂直軸Ｖ2 回りに回転可能に保持されている。このボス部５ｄには、上記前側移動輪８から車台１ｃの内側であって、その斜め後方に向けて突出するアーム部材５ｅが固定され、上記油圧シリンダ７Ｌ（７Ｒ）の一端がこのアーム部材５ｅの突出端に、他端が上記カバー６ａの上面であって、上記垂直軸Ｖ2 から離れた位置にそれぞれ連結されている。そして、上記油圧シリンダ７Ｌ（７Ｒ）は中立位置で上記前側移動輪８が車体１の直進方向に保持され、その中立位置から縮小されると、上記前側移動輪８が上記車体１に対して左向きに操舵され、逆に伸長すると上記前側移動輪８が上記車体１に対して右向きに操舵されるようになっている。また、上記各ブラケット６のカバー６ａの車体内側の側部には上記油圧モータ９がそれぞれ取付けられ、この各油圧モータ９は上記各前側移動輪８を直接的に回転駆動するようになっている。
【００２４】
一方、上記各後側支持脚３ｂは、ジャッキ部１１と、このジャッキ部１１の下端に固定されたブラケット１２と、このブラケット１２により水平軸Ｈ3 回りに回転可能に保持された後側移動輪１３とを備えている。そして、上記後側移動輪１３は、上記前側移動輪８と同様にパンクの発生による車体１の傾動が生じない中実のゴムタイヤにより形成されている。上記各ブラケット１２は上記各後側移動輪１３の接地部分を残して上部を覆うカバー１２ａ（図２参照）を備えている。
【００２５】
上記ジャッキ部１１は、上記前側支持脚３ａのジャッキ部５と対称に後方に向かって下り勾配になるように傾斜させた傾斜軸Ｘ2 を有して上記車体１に固定した有底角筒状の外筒１１ａを備えている。上記外筒１１ａ内には角筒状の内筒１１ｂが摺動可能に挿入されている。上記内筒１１ｂ内には、一端が内筒１１ｂの下端に、他端が上記外筒１１ａの上端にそれぞれ連結されたシリンダ１１ｃが収容されている。そして、上記シリンダ１１ｃの伸長及び縮小作動により車体１を上記浮上及び収納状態に変換可能にしている。
【００２６】
また、図２に示すように、上記内筒１１ｂの下端には、上記ブラケット１２を保持するボス部１１ｄが設けられている。該ボス部１１ｄの先端には、後側移動輪１３のホイール１４のリム１４ａより内方（ボス部１１ｄ側）へ膨出するディスク１４ｂがベアリング１５を介して回転自在に支持されている。尚、図２中１６は、ベアリング１５を車体外方から覆い隠すベアリングカバーである。
【００２７】
上記後側支持脚３ｂのカバー１２ａ上端には平面視で略矩形状を呈する開口１２ｂが設けられ、この開口１２ｂの前後両縁に断面略ハット状の取付ブラケット２１の下端が取付けられている。該取付ブラケット２１には、後側移動輪１３を制動する移動輪制動手段としての移動輪制動装置２２が取付けられている。図１にも示すように、この移動輪制動装置２２は、鉛直軸方向へ延びる軸線方向に伸縮動する制動シリンダ２３を備えている。該制動シリンダ２３は、ピストン２３ａによりヘッド側室２３ｂとロッド側室２３ｃとに区画され、そのヘッド側室２３ｂには、一端が油圧ポンプ２４に接続された圧油供給管２５の他端と、一端がリザーバタンク２６に接続された圧油排出管２７の他端とがそれぞれ接続されている。上記圧油供給管２５の途中にはアンロード弁２８が介設され、上記制動シリンダ２３のヘッド側室２３ｂの油圧が設定圧以上になったときに該ヘッド側室２３ｂの圧油をリザーバタンク２６に還流させるようにしている。また、上記圧油排出管２７の途中にはパイロット圧の作用により開放するパイロットチェック弁２９が介設されている。
【００２８】
そして、上記制動シリンダ２３のロッド２３ｄの先端にはステー３１を介してブレーキパッド３２が取付けられている。該ブレーキパッド３２は、平面視で上記ブラケット１２の開口１２ｂよりもひとまわり小さな略矩形状を呈し、上記圧油供給管２５より制動シリンダ２３のヘッド側室２３ｂに供給される圧油によりロッド２３ｄを伸長させることで、上記開口１２ｂを経て後側移動輪１３の外周部上端に押圧されるようになっている。また、上記制動シリンダ２３のロッド側室２３ｃには、ロッド２３ｄを収縮させる方向に付勢する圧縮スプリング３３が縮装されている。そして、上記パイロットチェック弁２９には、該パイロットチェック弁２９に上記油圧モータ９からパイロット圧を供給する流体作用管としてのパイロット圧供給管３４が接続されている。該パイロット圧供給管３４には、図示しない駆動ポンプより上記前側移動輪８を駆動させるよう給排管３５を経て油圧モータ９に対して供給される圧油の一部が供給され、この圧油の一部が上記パイロット圧供給管３４を経てパイロット圧としてパイロットチェック弁２９に作用することで、該パイロットチェック弁２９が開放するようになっている。上記パイロットチェック弁２９とパイロット圧供給管３４とで連通遮蔽手段３６が構成されている。この場合、油圧ポンプ２４により制動シリンダ２３に供給される圧油は１４０ｋｇ／ｃｍ²に設定されているのに対し、油圧モータ９からパイロット圧供給管３４に供給される圧油の一部つまりパイロット圧は１７５ｋｇ／ｃｍ²に設定され、パイロットチェック弁２９に高油圧のパイロット圧が効果的に作用するようになっている。
【００２９】
次に、上記構成の自走式作業車の動作について説明する。
【００３０】
高所作業を行う場合、パーキングブレーキを操作して後輪４ｂを制動状態にしてから、先に前側支持脚３ａのジャッキ部５により前側移動輪８を接地させて前輪４ａを浮上させ、油圧モータ９非駆動時の回転規制により前側移動輪８による制動を得た状態で、後側支持脚３ｂのジャッキ部１１により後側移動輪１３を接地させて後輪４ｂを浮上させることで、車体１を上記前後両支持脚３ａ，３ｂ（前後両移動輪８，１３）により支持し、ブーム２の起伏によりバケット２ｄを上昇させて高所作業を行う。そして、この高所作業時において油圧モータ９の駆動により上記車体１は超微速（例えば、１．５Ｋｍ／ｈ）で前後進して移動することが可能となるとともに、一対の油圧シリンダ７Ｌ，７Ｒを作動させて上記前側移動輪８，８を操舵することにより上記車体１は左右方向にも移動することが可能となる。
【００３１】
そして、この状態から通常走行を行う場合には、先に後側支持脚３ｂのジャッキ部１１により後輪４ｂを着地させて該後輪４ｂによる制動を得た状態で、前側支持脚３ａのジャッキ部５により前輪４ａを着地させることで、前後両支持脚３ａ，３ｂを収納状態にして車体１を上記前後車輪４ａ，４ｂにより支持し、通常走行を行うことが可能となる。
【００３２】
したがって、上記第１の実施形態では、後側移動輪１３は、油圧モータ９に圧油が供給されていない状態では、移動輪制動装置２２の制動シリンダ２３のヘッド側室２３ｂに圧油供給管２５を経て圧油が供給されることで、ロッド２３ｄが伸長してブレーキパッド３２が後側移動輪１３の外周部上端に押圧されて制動する一方、油圧モータ９に圧油が供給された場合には、この油圧モータ９に供給された圧油がパイロット圧供給管３４を経てパイロット圧としてパイロットチェック弁２９に作用し、該パイロットチェック弁２９が開放して圧油排出管２７が連通し、制動シリンダ２３のヘッド側室２３ｂの圧油がリザーバタンク２６に排出されることで、ロッド２３ｄが圧縮スプリング３３の付勢力により収縮して後側移動輪１３の外周部からブレーキパッド３２が離れて制動解除される。このため、油圧シリンダ２３のヘッド側室２３ｂに対して圧油を給排する圧油給排管２５，２７、並びにパイロットチェック弁２９にパイロット圧を作用させるパイロット圧供給管３４などの圧油流通系路のみで後側移動輪１３の制動解除が行え、複雑な電気的な制御による後側移動輪１３の制動解除を廃止して、電磁切換弁、支持脚接地検出器および支持脚ストローク検出器等の電気機器を不要にし、故障等によって誤作動、例えば前側および後側移動輪８，１３が地面に接地していない状態、または前輪４ａと後側移動輪１３との接地状態で後側移動輪１３の制動を解除するなどの誤作動が防止されて安全性を高ることができる。
【００３３】
しかも、移動輪制動装置２２の制動解除が制動シリンダ２３、圧油供給管２５、圧油排出管２７および連通遮蔽手段３６により行われることにより、高価な電気機器を廃止してコストダウンを図ることができる。
【００３４】
次に、本発明の第２の実施形態を図５に基づいて説明する。
【００３５】
この実施形態では、移動輪制動装置の構成を変更している。
【００３６】
すなわち、本実施形態では、図５に示すように、移動輪制動装置４１は制動シリンダ４２を備えている。該制動シリンダ４２は、ピストン４２ａによりヘッド側室４２ｂとロッド側室４２ｃとに区画されている。上記ヘッド側室４２ｂには一端が油圧ポンプ２４に接続された第１配管４３の他端が接続され、ロッド側室２３ｃには一端がリザーバタンク２６に接続された第２配管４４が接続されている。上記第１および第２配管４３，４４の途中には切換弁４５が介設されている。該切換弁４５は、制動シリンダ４２に対して第１配管４３を圧油供給可能にしかつ第２配管４４を圧油排出可能とする第１位置（図５では左位置）と、制動シリンダ４２に対して第１配管４３を圧油排出可能にしかつ第２配管４４を圧油供給可能とする第２位置（図５では右位置）とに切換えるよう移動するスプール４５ａを備えている。また、油圧モータ９と切換弁４５との間には流体作用管としての作動油圧供給管４６が接続されている。該作動油圧供給管４６には、駆動ポンプより上記前側移動輪８を駆動させるよう給排管３５を経て油圧モータ９に対して供給される作動圧油の一部が供給され、この作動圧油の一部が上記作動油圧供給管４６を経て切換弁４５のスプール４５ａに作用することで、該スプール４５ａが移動するようになっている。
【００３７】
そして、上記油圧モータ９の駆動により該油圧モータ９から作動油圧供給管４６を経て切換弁４５のスプール４５ａに作動圧油が作用する場合には、上記スプール４５ａが移動して切換弁４５が第１位置から第２位置に切換えられ、これにより、制動シリンダ４２と切換弁４５との間での第１および第２配管４３，４４内の圧油の流通方向が逆転し、制動シリンダ４２のヘッド側室４２ｂに油圧ポンプ２４からの圧油が第１配管４３を経て供給されかつロッド側室４２ｃの圧油が第２配管４４を経てリザーバタンク２６に還流することで、制動シリンダ４２のロッド４２ｄが収縮し、後側移動輪１３の外周部からブレーキパッド３２が離れて該後側移動輪１３が制動解除される。一方、上記油圧モータ９の駆動停止により該油圧モータ９の作動圧油が切換弁４５のスプール４５ａに作用しない場合には、上記スプール４５ａの移動が規制されて切換弁４５が第１位置に保持され、ロッド４２ｄが伸長状態に保持されてブレーキパッド３２が後側移動輪１３の外周部上端に押圧されて該後側移動輪１３が制動する。
【００３８】
したがって、上記第２の実施形態では、制動シリンダ４２と油圧ポンプ２４との間に介設した切換弁４５は、前側移動輪８を駆動させる際にのみ油圧モータ９から作動油圧供給管４６を経て供給される作動圧油によりスプール４５ａを移動させて第２位置に切換えられることで、制動シリンダ４２と切換弁４５との間での第１および第２配管４３，４４内の圧油の流通方向が逆転し、制動シリンダ４２のヘッド側室４２ｂに油圧ポンプ２４からの圧油が第１配管４３を経て供給されかつロッド側室４２ｃの圧油が第２配管４４を経てリザーバタンク２６に還流することで、制動シリンダ４２のロッド４２ｄが収縮し、後側移動輪１３の外周部からブレーキパッド３２が離れて該後側移動輪１３が制動解除される。制動シリンダ４２のロッド４２ｄが収縮し、後側移動輪１３の外周部からブレーキパッド３２が離れて該後側移動輪１３の制動が解除されるようになっているので、構造がシンプルでかつ安価な切換弁４５によって、さらなる安全性の向上およびコストダウンを達成できる。
【００３９】
尚、本発明は上記各実施形態に限定されるものではなく、その他種々の変形例を包含するものである。すなわち、上記各実施形態では、移動輪制動装置２２，４１により後側移動輪１３の制動および制動解除するようにしたが、移動輪制動装置を前側支持脚のカバーのブラケットに設け、この移動輪制動装置により前側移動輪の制動および制動解除が行われるようにしても良い。
【００４０】
さらに、上記各実施形態では、制動シリンダ２３（４２）のヘッド側室２３ｂ（４２ｂ）に圧油を供給する油圧ポンプ２４と、油圧モータ９に対して作動圧油を供給する駆動ポンプとをそれぞれ別個に設けたが、単一のポンプにより、制動シリンダのヘッド側室および油圧モータに対して圧油又は作動圧油がそれぞれ供給されるようにしても良い。この場合、油圧モータに対して供給される作動圧油が、制動シリンダのヘッド側室に対して供給される圧油よりも高圧に設定されるようになっている。
【００４１】
しかも、上記各実施形態では、前側移動輪８を車体１に対して左右方向に操舵できるようにしたが、後側移動輪が車体に対して左右方向に操舵できるように構成されていても良い。
【００４２】
また、上記各実施形態では、ブーム２を起伏および旋回可能に構成したが、ブームが起伏、伸縮および旋回可能に構成された作業装置であっても良いのは勿論のこと、その他高所での作業を行うあらゆる作業装置が適用されるのは勿論である。
【００４３】
【発明の効果】
以上の如く、請求項１および請求項２記載の発明における自走式作業車の移動輪制動解除装置によれば、移動輪制動手段の流体供給管を経た流体の供給により制動シリンダを伸長させて移動輪を制動させる一方、移動輪駆動時に移動輪駆動手段からの供給流体を流体作用管を経て移動輪制動手段の連通遮蔽手段に作用させ、制動シリンダからの流体排出管を経た流体排出により該制動シリンダを収縮させて移動輪を制動解除するので、移動輪駆動手段および移動輪制動手段への流体の流通系路のみでシンプルかつ安価に移動輪の制動解除を行うことができ、故障等による誤作動を防止して安全性の向上を図ることができるとともに、高価な電気機器の廃止に伴いコストダウンを図ることができる。
【００４４】
さらに、請求項３記載の発明における自走式作業車の移動輪制動解除装置によれば、移動輪駆動時、流体圧モータからの供給流体を流体作用管を経て切換弁に作用させることで、流体給排管の給排方向を切換えて移動輪制動手段による移動輪の制動を解除し、切換弁によるシンプル化および低廉化によって、さらなる安全性の向上およびコストダウンを達成することができる。
【図面の簡単な説明】
【図１】第１の実施形態に係る移動輪制動装置の油圧回路図である。
【図２】後側支持脚を示す一部切り欠き拡大図である。
【図３】前側支持脚を示す一部切り欠き拡大図である。
【図４】自走式作業車の側面図である。
【図５】第２の実施形態に係る移動輪制動装置の油圧回路図である。
【図６】後側支持脚を示す一部切り欠き拡大図である。
【符号の説明】
１ｃ車台
３支持脚
３ａ前側支持脚（一方の支持脚）
３ｂ後側支持脚（他方の支持脚）
８，１３移動輪
９油圧モータ（移動輪駆動手段）
２２，４１移動輪制動装置（移動輪制動手段）
２３，４２制動シリンダ
２５圧油供給管
２７圧油排出管
３４パイロット圧供給管（流体作用管）
３６連通遮蔽手段
４３，４４第１，第２配管（流体給排管）
４５切換弁
４６作動油圧供給管（流体作用管）[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a moving wheel braking release device for a self-propelled work vehicle having a moving wheel that moves the chassis with respect to the ground surface when the pair of left and right support legs before and after the chassis is extended. It relates to measures to ensure that it can be performed reliably and inexpensively
[0002]
[Prior art]
Conventionally, as disclosed in, for example, Japanese Utility Model Laid-Open No. 5-76929, a working device or the like that performs work at a high place by a bucket at the tip of a boom that is provided so as to be undulating and extendable and turnable with respect to the chassis. In the work vehicle and the like mounted on the front and rear wheels, there are provided four support legs that can be extended and retracted to support the chassis (work vehicle itself) when it is extended with respect to the ground surface. A moving wheel that can move the chassis when extended is provided at the lower end, and the work is continuously performed at a high place by the self-propelled movement of the moving wheel with the chassis supported by the support legs.
[0003]
Further, in such a self-propelled work vehicle, moving wheel drive means such as a hydraulic actuator is provided on the front support leg among the front and rear support legs, and the above-described operation is performed by the operation of the moving wheel drive means. The moving wheel of the front support leg is driven. In this case, in general, because the brake of the work vehicle is performed on the rear wheel, when each supporting leg is extended, the front supporting leg is first extended to ground the front moving wheel to the ground, and the moving wheel driving means In a non-operating state, that is, in a state where braking is obtained by restricting the rotation of the front moving wheel, the rear supporting leg is extended so that the front moving wheel contacts the ground. On the other hand, when each support leg is contracted, the rear support leg is first contracted to ground the rear wheel to the ground, and with the rear wheel being braked, the front support leg is contracted and the front wheel is grounded. To ground.
[0004]
However, the operator mistakenly operates the front and rear support legs to extend and retract the support legs on the back and extend the back support wheels to the ground first, When the front support leg is first contracted during contraction and the front wheels are brought into contact with the ground, there is a problem that the work vehicle will inadvertently run by itself.
[0005]
Therefore, in order to prevent such an operator's erroneous operation, a self-propelled work vehicle in which braking of the moving wheel is released by the moving wheel braking release device has been developed. This moving wheel braking release device includes a moving wheel braking means for braking the moving wheel of the rear supporting leg on the rear supporting leg so that the moving wheel braking can be performed even if an operator accidentally expands and contracts the supporting leg. Means prevent the work vehicle from being inadvertently driven by the braking force of the rear moving wheels. In this moving wheel braking release device, the moving wheel braking means includes a brake cylinder that brakes the rear moving wheel by supplying hydraulic pressure, an electromagnetic switching valve that switches supply and discharge of hydraulic pressure to the braking cylinder, and the electromagnetic switching valve. And a control leg stroke detector for detecting that the support leg is extended to the stroke end, and a signal from the support leg ground detector for detecting that the front and rear support legs are grounded. A signal from a device is input to the control unit, and by switching and controlling the electromagnetic switching valve based on these signals, hydraulic pressure is supplied to the brake cylinder to brake the rear moving wheel, The hydraulic pressure is discharged from the brake cylinder to release the brake on the rear moving wheel.
[0006]
[Problems to be solved by the invention]
However, in the case where the brake release of the moving wheel braking means as described above is performed by electrical control, there are the following drawbacks.
[0007]
That is, since the moving wheel braking means is equipped with electric devices such as an electromagnetic switching valve, a support leg grounding detector and a support leg stroke detector, the control at the time of releasing the brake becomes complicated and malfunctions due to a failure or the like, for example, movement There is a possibility of causing problems such as accidentally releasing the braking of the moving wheel when the wheel is not in contact with the ground. Moreover, since such an electric device is expensive, the cost of the moving wheel braking means is increased.
[0008]
The present invention has been made in view of such a point, and an object of the present invention is to make it possible to release the braking of the moving wheel by the moving wheel braking means with a simple configuration without performing electrical control. It is intended to improve the safety by preventing malfunction due to a failure or the like and to reduce the cost of the moving wheel braking means.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the solution provided by the invention according to claim 1 is provided such that a support leg having a moving wheel at the lower end is provided so as to be able to expand and contract by a pair of left and right before and after the chassis, and when the support legs extend, It is premised on a moving wheel braking release device for a self-propelled work vehicle configured such that each moving wheel is grounded so that the chassis is supported so as to be movable with respect to the ground surface. Further, one of the front and rear support legs is provided with moving wheel driving means for driving the moving wheel of the one supporting leg by supplying fluid while preventing the driving wheel from being driven by stopping supplying fluid. The other supporting leg is provided with moving wheel braking means for braking the moving wheel of the other supporting leg by supplying fluid while releasing the braking by stopping the supply of fluid. Then, when the supply of fluid by the moving wheel driving means is prohibited, the supply of fluid by the moving wheel braking means is performed to brake the moving wheel of the other support leg, thereby restricting the movement of the chassis. . On the other hand, when the fluid is supplied to the moving wheel driving means, the moving wheel braking means is prohibited from supplying the fluid to release the braking of the moving wheel of the other support leg, thereby moving the chassis. In addition, it is possible to release or brake the moving wheel of the other supporting leg only by prohibiting the supply of the fluid to the moving wheel driving means or the prohibition of the supply. This is a simple configuration.
[0010]
The solution provided by the invention according to claim 2 is characterized in that the moving wheel driving means and the moving wheel braking means of the invention according to claim 1 are specified. Specifically, the moving wheel driving means includes a fluid pressure motor that drives the moving wheel of one of the support legs by supplying fluid. On the other hand, a fluid supply pipe that supplies fluid to the moving wheel braking means, a telescopic brake cylinder that extends to brake the moving wheel of the other support leg by the fluid supplied through the fluid supply pipe, and the other The brake cylinder is contracted to release the brake of the moving wheels of the support legs, and a fluid discharge pipe for discharging the fluid from the brake cylinder is provided in the fluid discharge pipe, and the fluid discharge pipe communicates with the fluid discharge pipe. Communicating shielding means that shields fluid from being discharged, and is connected between the communicating shielding means and the fluid pressure motor, and is supplied when the moving wheel of the one supporting leg is driven so that the fluid discharge pipe communicates with the fluid discharge pipe. And a fluid action tube that causes the fluid from the fluid pressure motor to act on the communication shielding means.
[0011]
As a result, in the first and second aspects of the invention, when the supply of fluid to the moving wheel driving means such as a fluid pressure motor is prohibited so as not to drive the moving wheel of one of the front and rear support legs, The moving wheel of the other supporting leg is braked by supplying the fluid by the wheel braking means, for example, the braking cylinder is extended by the fluid supplied through the fluid supply pipe to brake the moving wheel of the other supporting leg.
[0012]
On the other hand, when the fluid is supplied to the moving wheel driving means (fluid pressure motor) so as to drive the moving wheel of the one support leg, the supply of fluid by the moving wheel braking means is prohibited and the other wheel is prohibited. Release the brake of the moving wheel of the supporting leg, for example, the fluid from the fluid pressure motor supplied when driving the moving wheel of one supporting leg is made to act on the communication shielding means in the middle of the fluid discharging pipe through the fluid action pipe. The fluid from the brake cylinder is discharged through the fluid discharge pipe, the brake cylinder is contracted, and the moving wheel of the other support leg by the brake cylinder is released from the brake.
[0013]
As a result, the braking of the moving wheel braking means can be easily released only by the fluid flow path such as the fluid supply / discharge pipe to the moving wheel driving means and the moving wheel braking means, and the braking of the moving wheels by complicated electrical control is possible. Canceling the release, eliminating the need for electrical devices such as electromagnetic switching valves, support leg grounding detectors and support leg stroke detectors, and malfunctions due to failure of electrical equipment, such as when the moving wheel is not grounded to the ground In addition to preventing erroneous operation such as accidentally releasing the braking of the moving wheel, even if the operator operates the operating order of the front and rear support legs incorrectly, braking by the moving wheel is reliably obtained, and safety is improved. It is done. Moreover, the brake release of the moving wheel braking means is performed by the brake cylinder, the fluid supply pipe, the fluid discharge pipe, the communication shielding means, and the fluid action pipe, so that expensive electric equipment is not required and the cost is reduced.
[0014]
Further, the solution provided by the invention according to claim 3 is characterized in that the moving wheel driving means and the moving wheel braking means of the invention according to claim 1 are specified. Specifically, the moving wheel driving means includes a fluid pressure motor that drives the moving wheel of one of the support legs by supplying fluid. On the other hand, a fluid supply and discharge pipe for supplying and discharging fluid to the moving wheel braking means, a brake cylinder extending by fluid supplied and discharged through the fluid supply and discharge pipe so as to brake the moving wheel of the other support leg, The brake cylinder is contracted by the fluid supplied and discharged through the fluid supply / discharge pipe so as to release the braking of the moving wheel of the other support leg, which is interposed in the fluid supply / discharge pipe, thereby supplying and discharging the fluid supply / discharge pipe. A switching valve that switches the direction, and a fluid pressure that is connected between the switching valve and the fluid pressure motor, and that is supplied when the moving wheel of the one support leg is driven so that the supply / discharge direction of the fluid supply / discharge pipe is switched. A fluid working tube that causes the fluid from the motor to act on the switching valve is provided.
[0015]
Thus, according to the third aspect of the present invention, the switching valve interposed in the fluid supply / discharge pipe drives the moving wheel when the moving wheel of one support leg is driven by the moving wheel driving means (fluid pressure motor). It is switched by the fluid supplied from the means through the fluid action pipe, and the supply / discharge direction of the fluid in the fluid supply / discharge pipe is reversed to release the braking of the moving wheel of the other support leg, so the structure is simple. In addition, the brake of the moving wheel braking means is released by an inexpensive switching valve, and further safety improvement and cost reduction are achieved.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 4 shows a self-propelled work vehicle equipped with a moving wheel braking release device according to the first embodiment of the present invention, wherein 1 is a vehicle body and 2 is a work device installed on the vehicle body 1 so as to be able to undulate and turn. The boom 1 is a support leg that supports the vehicle body 1 in a floating state and movably when working at a high place.
[0018]
The vehicle body 1 is composed of a chassis 1c, a loading platform 1a provided on the chassis 1c, and a vehicle compartment 1b integrally connected to the chassis 1c. The normal driving is performed by driving the wheels 4a and 4b, and the front wheel 4a becomes a wheel during normal driving. In this case, when a parking brake (not shown) is operated while the vehicle body 1 is stopped, braking by the rear wheel 4b can be obtained.
[0019]
The boom 2 is connected to the chassis 1c so as to be rotatable about a vertical axis V1, and is connected to the upper end of the rotary column 2a so as to be rotatable about a horizontal axis H1, and a hoisting cylinder. The telescopic tube 2c connected to be able to undulate by 2b and a working bucket 2d provided at the tip of the telescopic tube 2c, and an operator rides on the bucket 2d to extend the undulating cylinder 2b. As a result, the bucket 2d rises relative to the chassis 1c.
[0020]
The support legs 3 are a pair of left and right front support legs 3a (one support leg) provided on the front side of the chassis 1c and a pair of left and right rear support legs 3b (the other support leg) provided on the rear side of the chassis 1c. It consists of.
[0021]
Each of the front support legs 3a (because they have the same configuration, only the left one shown in FIG. 3 is given a reference numeral, and the right one is only given a different reference in parentheses and the description thereof is omitted). As shown in detail on the left side in FIG. 3, a jack portion 5 is provided. A bracket 6 is rotatably held around the vertical axis V2 at the lower end of the jack portion 5, and the bracket 6 is rotated by a hydraulic cylinder 7L (7R). A front moving wheel 8 is held on the bracket 6 so as to be rotatable about a horizontal axis H2, and the front moving wheel 8 is configured as a steering wheel during high-altitude work. The bracket 6 is provided with a hydraulic motor 9 (fluid pressure motor) as a moving wheel driving means for rotating the front moving wheel 8. The front-side moving wheel 8 is in a state where the rotation is restricted when the hydraulic motor 9 is not driven and braking is obtained. The front moving wheel 8 is formed of a solid rubber tire so that the vehicle body 1 is not tilted due to occurrence of puncture. 3 and 4 show only the left front support leg 3a, the right one is configured similarly to the left one.
[0022]
Each of the jack portions 5 is disposed in the vertical direction with respect to the chassis 1c, and has an inclined axis X1 inclined so that the bottomed rectangular tube-shaped outer tube 5a is inclined downward toward the front. It is fixed to the chassis 1c. In this outer cylinder 5a, a rectangular inner cylinder 5b is slidably inserted. Housed in the inner cylinder 5b is a cylinder 5c having one end connected to the lower end of the inner cylinder 5b and the other end connected to the upper end of the outer cylinder 5a. A boss portion 5d for holding the bracket 6 is fixed to the lower end of the inner cylinder 5b. Although not shown, the bracket 6 supports a disk that swells inwardly (in the direction of the horizontal axis H2) from the rim of the wheel of the front moving wheel 8 via a bearing. In each jack portion 5, the floating state in which the inner cylinder 5b protrudes from the outer cylinder 5a by the extension operation of the cylinder 5c and the front side moving wheel 8 is pushed obliquely downward to lift the vehicle body 1 (FIG. 3 and FIG. 3). 4 is shown in a one-dot chain line), and by the reduction operation, the inner cylinder 5b is immersed in the outer cylinder 5a and the traveling wheels 4a and 4b are grounded (state shown by a solid line in the figure). It has become so.
[0023]
Each bracket 6 includes a cover 6a that covers the upper part of the front moving wheel 8 while leaving a grounding portion, and a shaft portion 6b that protrudes upward from the upper surface of the cover 6a. The shaft portion 6b is the boss portion 5d. Is held so as to be rotatable around the vertical axis V2. The boss 5d is fixed with an arm member 5e that protrudes obliquely rearward from the front moving wheel 8 to the inside of the chassis 1c, and one end of the hydraulic cylinder 7L (7R) is connected to the arm member 5e. The other end is connected to the upper surface of the cover 6a at a position away from the vertical axis V2. When the hydraulic cylinder 7L (7R) is held in the neutral position, the front moving wheel 8 is held in the straight direction of the vehicle body 1, and when the hydraulic cylinder 7L (7R) is contracted from the neutral position, the front moving wheel 8 moves leftward with respect to the vehicle body 1. The front moving wheel 8 is steered to the right with respect to the vehicle body 1 when it is extended to the opposite direction. Further, the hydraulic motors 9 are respectively attached to the side portions of the covers 6a of the brackets 6 on the inner side of the vehicle body. The hydraulic motors 9 directly drive the front moving wheels 8 to rotate. .
[0024]
On the other hand, each of the rear support legs 3b includes a jack portion 11, a bracket 12 fixed to the lower end of the jack portion 11, and a rear moving wheel 13 rotatably held around the horizontal axis H3 by the bracket 12. And. The rear moving wheel 13 is formed of a solid rubber tire that does not cause the vehicle body 1 to tilt due to the occurrence of puncture, as with the front moving wheel 8. Each bracket 12 includes a cover 12a (see FIG. 2) that covers the upper portion of the rear moving wheel 13 while leaving the ground contact portion.
[0025]
The jack portion 11 has a bottomed rectangular tube shape fixed to the vehicle body 1 with an inclination axis X2 inclined so as to be inclined downward toward the rear symmetrically with the jack portion 5 of the front support leg 3a. An outer cylinder 11a is provided. A square cylindrical inner cylinder 11b is slidably inserted into the outer cylinder 11a. The inner cylinder 11b accommodates a cylinder 11c having one end connected to the lower end of the inner cylinder 11b and the other end connected to the upper end of the outer cylinder 11a. The vehicle body 1 can be converted into the floating and retracted state by the extension and reduction operations of the cylinder 11c.
[0026]
Further, as shown in FIG. 2, a boss portion 11d for holding the bracket 12 is provided at the lower end of the inner cylinder 11b. A disk 14b that swells inward (to the boss 11d side) from the rim 14a of the wheel 14 of the rear moving wheel 13 is rotatably supported via a bearing 15 at the tip of the boss 11d. 2 denotes a bearing cover that covers the bearing 15 from the outside of the vehicle body.
[0027]
An opening 12b having a substantially rectangular shape in plan view is provided at the upper end of the cover 12a of the rear support leg 3b, and the lower end of a mounting bracket 21 having a substantially hat-shaped cross section is attached to both front and rear edges of the opening 12b. A moving wheel braking device 22 is attached to the mounting bracket 21 as moving wheel braking means for braking the rear moving wheel 13. As shown in FIG. 1, the moving wheel braking device 22 includes a braking cylinder 23 that expands and contracts in the axial direction extending in the vertical axis direction. The brake cylinder 23 is partitioned into a head side chamber 23b and a rod side chamber 23c by a piston 23a. The head side chamber 23b has a pressure oil supply pipe 25 having one end connected to a hydraulic pump 24 and one end a reservoir. A pressure oil discharge pipe 27 connected to the tank 26 is connected to the other end. An unload valve 28 is interposed in the middle of the pressure oil supply pipe 25, and when the oil pressure in the head side chamber 23b of the brake cylinder 23 becomes equal to or higher than a set pressure, the pressure oil in the head side chamber 23b is supplied to the reservoir tank 26. It is made to reflux. A pilot check valve 29 that is opened by the action of pilot pressure is interposed in the middle of the pressure oil discharge pipe 27.
[0028]
A brake pad 32 is attached to the tip of the rod 23d of the brake cylinder 23 via a stay 31. The brake pad 32 has a substantially rectangular shape slightly smaller than the opening 12b of the bracket 12 in plan view, and the rod 23d is pressed by the pressure oil supplied from the pressure oil supply pipe 25 to the head side chamber 23b of the brake cylinder 23. By extending, the upper end of the outer peripheral portion of the rear moving wheel 13 is pressed through the opening 12b. A compression spring 33 that urges the rod 23d in the direction in which the rod 23d is contracted is mounted in the rod side chamber 23c of the brake cylinder 23. The pilot check valve 29 is connected to a pilot pressure supply pipe 34 as a fluid working pipe for supplying a pilot pressure from the hydraulic motor 9 to the pilot check valve 29. The pilot pressure supply pipe 34 is supplied with a part of the pressure oil supplied to the hydraulic motor 9 through the supply / discharge pipe 35 so as to drive the front moving wheel 8 from a drive pump (not shown). A part of the air pressure acts on the pilot check valve 29 as a pilot pressure through the pilot pressure supply pipe 34, so that the pilot check valve 29 is opened. The pilot check valve 29 and the pilot pressure supply pipe 34 constitute a communication shielding means 36. In this case, the pressure oil supplied to the brake cylinder 23 by the hydraulic pump 24 is 140 kg / cm. ² However, a part of the pressure oil supplied to the pilot pressure supply pipe 34 from the hydraulic motor 9, that is, the pilot pressure is 175 kg / cm. ² Thus, a high hydraulic pilot pressure effectively acts on the pilot check valve 29.
[0029]
Next, the operation of the self-propelled work vehicle having the above configuration will be described.
[0030]
When working at a high place, the parking brake is operated to bring the rear wheel 4b into a braking state, and then the front moving wheel 8 is grounded by the jack portion 5 of the front support leg 3a, and the front wheel 4a is lifted. 9 In a state where braking by the front side moving wheel 8 is obtained by the rotation restriction when not driven, the rear side moving wheel 13 is grounded by the jack portion 11 of the rear side support leg 3b and the rear wheel 4b is floated, thereby Is supported by the above-described front and rear support legs 3a and 3b (both front and rear moving wheels 8 and 13), and the bucket 2d is lifted by raising and lowering the boom 2 to perform work at a high place. During this high-altitude work, the vehicle body 1 can move back and forth at an extremely slow speed (for example, 1.5 Km / h) by driving the hydraulic motor 9, and a pair of hydraulic cylinders 7L, The vehicle body 1 can also be moved in the left-right direction by operating the front moving wheels 8 and 8 by operating the 7R.
[0031]
When normal running is performed from this state, the jack of the front support leg 3a is obtained in a state where the rear wheel 4b is first landed by the jack portion 11 of the rear support leg 3b and braking is performed by the rear wheel 4b. By landing the front wheel 4a by the portion 5, the vehicle body 1 can be supported by the front and rear wheels 4a and 4b with both the front and rear support legs 3a and 3b being stored, and normal traveling can be performed.
[0032]
Therefore, in the first embodiment, the rear moving wheel 13 has the pressure oil supply pipe 25 in the head side chamber 23b of the brake cylinder 23 of the moving wheel braking device 22 in a state where no pressure oil is supplied to the hydraulic motor 9. When the pressure oil is supplied through the above, the rod 23d extends and the brake pad 32 is pressed against the upper end of the outer peripheral portion of the rear moving wheel 13 for braking, while the hydraulic motor 9 is supplied with the pressure oil. The pressure oil supplied to the hydraulic motor 9 acts as a pilot pressure on the pilot check valve 29 via the pilot pressure supply pipe 34, the pilot check valve 29 is opened, and the pressure oil discharge pipe 27 communicates with the brake. When the pressure oil in the head side chamber 23b of the cylinder 23 is discharged to the reservoir tank 26, the rod 23d is contracted by the urging force of the compression spring 33 so that the outer peripheral portion of the rear moving wheel 13 Brake pad 32 is a brake releasing away. For this reason, a pressure oil distribution system such as pressure oil supply and discharge pipes 25 and 27 for supplying and discharging pressure oil to the head side chamber 23b of the hydraulic cylinder 23 and a pilot pressure supply pipe 34 for applying a pilot pressure to the pilot check valve 29. The braking of the rear moving wheel 13 can be released only by the road, the braking release of the rear moving wheel 13 by complicated electrical control is abolished, an electromagnetic switching valve, a supporting leg grounding detector, a supporting leg stroke detector, etc. The rear moving wheel in the state where the front and rear moving wheels 8 and 13 are not in contact with the ground or the grounding state between the front wheel 4a and the rear moving wheel 13 is eliminated. Thus, the malfunction such as releasing the brake 13 can be prevented and the safety can be improved.
[0033]
In addition, the brake release of the moving wheel braking device 22 is performed by the brake cylinder 23, the pressure oil supply pipe 25, the pressure oil discharge pipe 27, and the communication shielding means 36, thereby eliminating expensive electric equipment and reducing costs. Can do.
[0034]
Next, a second embodiment of the present invention will be described with reference to FIG.
[0035]
In this embodiment, the configuration of the moving wheel braking device is changed.
[0036]
That is, in the present embodiment, the moving wheel braking device 41 includes a braking cylinder 42 as shown in FIG. The brake cylinder 42 is partitioned into a head side chamber 42b and a rod side chamber 42c by a piston 42a. The head side chamber 42b is connected to the other end of a first pipe 43 having one end connected to the hydraulic pump 24, and the rod side chamber 23c is connected to a second pipe 44 having one end connected to the reservoir tank 26. A switching valve 45 is interposed in the middle of the first and second pipes 43 and 44. The switching valve 45 is connected to the brake cylinder 42 at a first position (a left position in FIG. 5) where the first pipe 43 can be supplied with pressure oil and the second pipe 44 can be discharged with pressure oil. On the other hand, a spool 45a is provided that moves so as to switch to a second position (right position in FIG. 5) where the first pipe 43 can discharge pressure oil and the second pipe 44 can supply pressure oil. Further, an operating hydraulic pressure supply pipe 46 as a fluid action pipe is connected between the hydraulic motor 9 and the switching valve 45. The hydraulic pressure supply pipe 46 is supplied with a part of the hydraulic pressure oil supplied to the hydraulic motor 9 via the supply / discharge pipe 35 so as to drive the front moving wheel 8 from the drive pump. A part of the spool 45a acts on the spool 45a of the switching valve 45 through the hydraulic pressure supply pipe 46, so that the spool 45a moves.
[0037]
Then, when the hydraulic pressure oil acts on the spool 45a of the switching valve 45 from the hydraulic motor 9 through the hydraulic pressure supply pipe 46 by driving the hydraulic motor 9, the spool 45a moves and the switching valve 45 is moved to the first position. By switching from the first position to the second position, the flow direction of the pressure oil in the first and second pipes 43 and 44 between the brake cylinder 42 and the switching valve 45 is reversed, and the head of the brake cylinder 42 The pressure oil from the hydraulic pump 24 is supplied to the side chamber 42b via the first pipe 43, and the pressure oil in the rod side chamber 42c returns to the reservoir tank 26 via the second pipe 44, so that the rod 42d of the brake cylinder 42 contracts. Then, the brake pad 32 is separated from the outer peripheral portion of the rear moving wheel 13 and the braking of the rear moving wheel 13 is released. On the other hand, when the hydraulic pressure of the hydraulic motor 9 does not act on the spool 45a of the switching valve 45 due to the driving stop of the hydraulic motor 9, the movement of the spool 45a is restricted and the switching valve 45 is held at the first position. Then, the rod 42d is held in the extended state, and the brake pad 32 is pressed against the upper end of the outer peripheral portion of the rear moving wheel 13 so that the rear moving wheel 13 is braked.
[0038]
Therefore, in the second embodiment, the switching valve 45 interposed between the brake cylinder 42 and the hydraulic pump 24 passes from the hydraulic motor 9 through the hydraulic pressure supply pipe 46 only when driving the front moving wheel 8. The spool 45a is moved by the supplied operating pressure oil and switched to the second position, so that the pressure oil flows in the first and second pipes 43 and 44 between the brake cylinder 42 and the switching valve 45. Is reversed, pressure oil from the hydraulic pump 24 is supplied to the head side chamber 42b of the brake cylinder 42 via the first pipe 43, and pressure oil in the rod side chamber 42c is returned to the reservoir tank 26 via the second pipe 44. Then, the rod 42d of the brake cylinder 42 contracts, the brake pad 32 is separated from the outer peripheral portion of the rear moving wheel 13, and the rear moving wheel 13 is released from braking. Since the rod 42d of the brake cylinder 42 contracts and the brake pad 32 is separated from the outer peripheral portion of the rear moving wheel 13 to release the braking of the rear moving wheel 13, the structure is simple and inexpensive. With the simple switching valve 45, further safety improvement and cost reduction can be achieved.
[0039]
In addition, this invention is not limited to said each embodiment, A various other modification is included. That is, in each of the above embodiments, the rear wheel 13 is braked and released by the moving wheel braking devices 22 and 41. However, the moving wheel braking device is provided on the bracket of the front support leg cover. The braking and braking release of the front moving wheel may be performed by the braking device.
[0040]
Further, in each of the above embodiments, the hydraulic pump 24 that supplies pressure oil to the head side chamber 23b (42b) of the brake cylinder 23 (42) and the drive pump that supplies hydraulic pressure oil to the hydraulic motor 9 are separately provided. However, the pressure oil or the working pressure oil may be supplied to the head side chamber of the brake cylinder and the hydraulic motor by a single pump. In this case, the working pressure oil supplied to the hydraulic motor is set to be higher than the pressure oil supplied to the head side chamber of the brake cylinder.
[0041]
Moreover, in each of the above embodiments, the front moving wheel 8 can be steered in the left-right direction with respect to the vehicle body 1, but the rear moving wheel may be steered in the left-right direction with respect to the vehicle body. .
[0042]
Moreover, in each said embodiment, although the boom 2 was comprised so that raising / lowering was possible, of course, the boom may be a working device comprised so that raising / lowering, expansion-contraction, and turning were possible, and in other high places. Of course, any working device that performs work is applied.
[0043]
【The invention's effect】
As described above, according to the moving wheel brake releasing device of the self-propelled working vehicle according to the first and second aspects of the present invention, the brake cylinder is extended by supplying the fluid through the fluid supply pipe of the moving wheel braking means. While the moving wheel is braked, the supply fluid from the moving wheel driving means is applied to the communication shielding means of the moving wheel braking means via the fluid action tube when driving the moving wheel, and the fluid is discharged from the brake cylinder via the fluid discharge pipe. Since the brake is released by contracting the brake cylinder, the brake of the moving wheel can be released simply and inexpensively only by the fluid flow path to the moving wheel driving means and the moving wheel braking means. In addition to preventing malfunctions, safety can be improved, and costs can be reduced with the abolition of expensive electrical equipment.
[0044]
Furthermore, according to the moving wheel brake release device of the self-propelled working vehicle in the invention according to claim 3, when the moving wheel is driven, the supply fluid from the fluid pressure motor is caused to act on the switching valve via the fluid action tube. By switching the supply / discharge direction of the fluid supply / discharge pipe and releasing the braking of the moving wheel by the moving wheel braking means, the safety can be further improved and the cost can be reduced by the simplification and cost reduction by the switching valve.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram of a moving wheel braking device according to a first embodiment.
FIG. 2 is a partially cutaway enlarged view showing a rear support leg.
FIG. 3 is a partially cutaway enlarged view showing a front support leg.
FIG. 4 is a side view of the self-propelled work vehicle.
FIG. 5 is a hydraulic circuit diagram of a moving wheel braking device according to a second embodiment.
FIG. 6 is a partially cutaway enlarged view showing a rear support leg.
[Explanation of symbols]
1c chassis
3 Support legs
3a Front support leg (one support leg)
3b Rear support leg (the other support leg)
8,13 Moving wheel
9 Hydraulic motor (moving wheel drive means)
22, 41 Moving wheel braking device (moving wheel braking means)
23, 42 Brake cylinder
25 Pressure oil supply pipe
27 Pressure oil discharge pipe
34 Pilot pressure supply pipe (fluid working pipe)
36 Communication shielding means
43,44 1st and 2nd piping (fluid supply and exhaust pipe)
45 selector valve
46 Hydraulic pressure supply pipe (fluid action pipe)

Claims

A pair of left and right support legs with moving wheels at the lower end are provided to extend in front and rear of the chassis, and the chassis supports the pedestal so that it can move with respect to the ground surface when each of the support legs is extended. A mobile wheel braking release device for a self-propelled work vehicle configured to be
One of the front and rear support legs is provided with moving wheel driving means for driving the moving wheel of the one supporting leg by supplying fluid, but not driving by stopping the supply of fluid. The supporting leg is provided with moving wheel braking means for braking the moving wheel of the other supporting leg by supplying fluid while releasing the brake by stopping supplying fluid.
When the supply of material flow in the moving wheel driving means is prohibited, the moving wheel braking means in the flow-supplying of is made in braking movement wheels of the other support legs, the movement of the chassis is restricted While it is supposed to be
When fluid is supplied to the moving wheel driving means, the supply of fluid to the moving wheel braking means is prohibited, the moving wheel of the other support leg is released, and the chassis moves. The moving wheel of the self-propelled working vehicle is characterized in that braking or releasing of the moving wheel of the other support leg is performed only by prohibiting the supply of fluid to the moving wheel driving means or the prohibition of supply. Braking release device.

The moving wheel driving means includes a fluid pressure motor that drives the moving wheel of the one support leg by supplying fluid,
On the other hand, the moving wheel braking means includes a fluid supply pipe for supplying a fluid, a telescopic brake cylinder extending to brake the moving wheel of the other support leg by the fluid supplied through the fluid supply pipe, The brake cylinder is contracted to release the brake of the moving wheel of the other support leg, and a fluid discharge pipe is provided to discharge the fluid from the brake cylinder. The fluid discharge pipe is provided with the fluid discharge pipe so that the fluid can be discharged. Communicating shielding means for shielding communication or fluid discharge impossible, connected between the communication shielding means and the fluid pressure motor, and moving wheel drive of the one support leg so that the fluid discharge pipe communicates with the fluid dischargeable 2. The moving wheel brake releasing device for a self-propelled working vehicle according to claim 1, further comprising a fluid action tube for causing fluid from a fluid pressure motor supplied at times to act on the communication shielding means.

The moving wheel driving means includes a fluid pressure motor that drives the moving wheel of the one support leg by supplying fluid,
On the other hand, the moving wheel braking means includes a fluid supply / discharge pipe for supplying and discharging fluid, and a brake cylinder extending by fluid supplied and discharged through the fluid supply / discharge pipe so as to brake the moving wheel of the other support leg. The brake cylinder is contracted by the fluid supplied and discharged through the fluid supply / discharge pipe so as to release the braking of the moving wheel of the other support leg, which is interposed in the fluid supply / discharge pipe, A switching valve that switches the supply / discharge direction, and is connected between the switching valve and the fluid pressure motor, and is supplied when the moving wheel of the one support leg is driven so as to switch the supply / discharge direction of the fluid supply / discharge pipe. 2. The moving wheel braking release device for a self-propelled working vehicle according to claim 1, further comprising a fluid action tube that causes fluid from a fluid pressure motor to act on the switching valve.