JP4742480B2 - Steering control device for work vehicle - Google Patents

Description

【００４１】
そして前記コントローラ６では、ＳＴＥＰ３で、前記ハンドル切角センサ５の検出により車両の操向量を判定し、これが所定量を超えると車体が操向状態であると判定して、ＳＴＥＰ４にて予め設定された補正テーブルの補正値で左右クローラ回転を変速するフィードバック制御を実行する。
【００４２】
前記フィードバック制御では、左右クローラ１，１の回転数から旋回外側のクローラ１の回転に対する旋回内側のクローラ１の回転数比を演算し、これが前記設定回転数比に一致するよう所定の補正値を定めたテーブルに基づいてクラッチ圧、即ち比例圧力制御弁９１のソレノイド９１ｓへの通電量を補正する。
【００４３】
また、上記補正値は、後述するように、設定回転数比が０に近い程、即ち旋回内側のクローラ１が停止する状態に近づく程、補正値を小さく設定し、且つ前記実測回転数比と設定回転数比との差が大きいほど補正量（クラッチ圧）を大きく設定する構成となっている。また前記補正は繰り返し実行され、前記検出時のクラッチ圧に対し周期的に付加していくものであるが、▲１▼ステアリングハンドル４を直進位置に戻したとき、▲２▼変速位置を変更したとき、そして▲３▼スピンターン入切スイッチ２８が「入」の場合でスピンターン域まで達したときに、クリアして新たな補正を開始する構成となっている。
【００４４】
例えば、図１に示すように、変速位置を「低２」に設定し、前記スピンターンを「入」とした状態では、Ｌｂなる設定回転数比が設定される。ここでは、ステアリングハンドル４を切っていくと、前記図１中（Ｂ）の回転比となるよう旋回内側の逆転用クラッチ７Ｒが昇圧される。
【００４５】
この設定回転数比Ｌｂでは、ステアリング操作初期に約２０°内にあそびの領域があり、その後、前記副変速位置が「高」の場合（図１１参照）よりも急激に逆転用クラッチ７Ｒが昇圧され、更にステアリングハンドル４を切り続け、左右約１２０°を超えると、前記旋回内側の前進用クラッチ７Ｆのディスク７Ｆａ，７Ｆｂが完全に解除され、クローラ１が停止しロックターン状態となる。更にステアリングハンドル４を切り続け、約１５０°を超えるとクラッチ圧を急激に上昇し前記逆転用クラッチ７Ｒが圧着して旋回内側のクローラ１が逆転しスピンターンの状態となる。またこの操向制御に於けるフィードバック制御では、前記テーブルに基づく補正値が繰り返し付加される。
【００４６】
この補正による特徴を更に図１で説明すると、例えばステアリング切れ角が約９０°の状態では設定回転数比が約０．５に設定されている。このとき検出回転数比と設定回転数比の差がプラス側（ポイントａ）であれば、トラクタＴは想定よりも大回りの状態であるので、これを設定回転数比に近づけるべく前記テーブルに設定された補正量に基づき前記クラッチ圧力をプラス側に補正する。尚、この補正量は、前記差が大きいほど大きく設定されている。
【００４７】
また同じくステアリング切れ角が約９０°の状態で検出回転数比と設定回転数比の差がマイナス側（ポイントｂ）であれば、トラクタＴは設定よりも小回り状態であるので、クラッチ圧力をマイナス側に補正する。尚、ポイントｂでの設定回転数比Ｌｂとの差は、前記ポイントａでの差と同じ絶対量となっているが、補正量は前記プラス側の補正量よりも大きく設定されている。
【００４８】
また例えばステアリング切れ角が約１００°の状態では設定回転数比が約０．４に設定されている。このとき検出回転数比と設定回転数比の差がプラス側（ポイントｃ）であれば、トラクタＴは大回りの状態であるので、これを設定回転数比に近づけるべく前記テーブルに基づきクラッチ圧力をプラス側に補正する。そしてこの補正量は、前記ステアリング切れ角が９０°の時で同じ差のよりも、小さい値に設定されている。一方、同じく検出回転数比と設定回転数比の差がマイナス側（ポイントｄ）であれば、トラクタＴは設定よりも小回り状態であるので、これを設定回転数比に近づけるべく前記テーブルに基づきクラッチ圧力をマイナス側に補正する。そしてこの補正量は、前述同様、検出回転数と設定回転数の差の絶対量が同じでも、マイナ側の補正量の方が、プラス側の補正量よりも大きく設定されている。
【００４９】
また前記クラッチ圧は、図１２に示すように、前記補正やステアリング操作が無い場合にも、保持圧（Ｐ２）を保持すべく周期的に脈動圧（Ｐ３）与えクローラ１の回転数を保持する構成となっている。図中符号Ｐ１は、前記補正やステアリング操作維時に、最初に与える初期圧を示す。また図中時間Ｔ１，Ｔ２，Ｔ３は、各圧の継続時間を示し、Ｔ１＞Ｔ２＞Ｔ３の関係となっている。
【００５０】
尚、前記設定回転数比は、各クラッチ７Ｆ，７Ｒの仕様やトラクタＴの型式等により実験から求められたものであり、これら設定回転数比、及び前記補正量は、前記携帯用チェッカー９５によって変更可能な構成となっている。また前記逆転用クラッチ７Ｒや各種油圧機器等の個体差があるため、前記補正テーブルを左右別々に設定したり、旋回域即ち、マイルドターン域とロックターン域、スピンターン域毎に設定する構成としても良い。また更に、前記昇圧カーブは、各変速位置毎に設定し、前記同様、変速位置が高速に設定される程、昇圧カーブを緩やかに設定しても良い。
【００５１】
以上のように構成したトラクタＴの操向制御装置では、車両の左右操向量が検出され、この操向量に応じた設定回転数比を得るよう無段変速装置２，２の出力回転数が適宜補正され、この時の補正は、検出時の駆動状態に対し所定の補正量を繰り返し付加するものであるから、クローラ１，１の回転数は徐々に設定回転数比に近づく。
【００５２】
これにより、クローラ１，１の駆動力が大きく変化することが無いので、円滑な操向を行うことができる。
また前記無段変速装置２を湿式多板形態の逆転用クラッチ７Ｒを有する形態とした場合、前記クラッチ板が圧着する方向と解除する方向との操作力の違いや時間差といった特性による差異を低減し、一律な補正量を付加する構成と比較して、円滑且つ迅速なフィードバック制御を行って、円滑な操向を行うことができる。
【００５３】
一方、前記ＳＴＥＰ３の判定にて、車体が操向状態でない場合には、ＳＴＥＰ５へ進み、前記比例圧力制御弁９１のソレノイド９１ｓへの通電を停止すると共に、ＳＴＥＰ６で回転センサ３の故障診断処理を行う。
この故障診断処理では、図１３に示すように、まずＳＴＥＰ１で、前記検出部の内第一相目の故障診断を行う。ここでは、第一相目は、ギヤ回転数、即ちクローラ１の回転速を検出するものであり、所定時間内の左右の回転センサ３，３の第一相目同士の検出波形の数に差があるかどうかを判定し、
、この差が所定回数超える差があるときに故障と判定し（ＳＴＥＰ２）、これがＹＥＳの場合にＳＴＥＰ３にて、前記システム異常警報ランプ８５を点灯する。
【００５４】
また前記ＳＴＥＰ２にて異常が無い場合は、ＳＴＥＰ４へ進み、前記回転前記ランプ８５が点灯している場合は消灯する。
また、ＳＴＥＰ５では、前記回転センサ３の第二相目の故障診断を行う。図１４に基づき説明すると、片方の回転センサ（図中上段の左クローラ回転センサ３）において、第一相の波形が立上ったとき（Ｔ１）に、第二相の波形を比較、即ち波形のピークが検出されると正常と判定し、これを前記回転検出用ギヤ８の一回転に相当するギヤパルス数において所定数以上のピークを検出しないときに故障と判定する。
【００５５】
尚、他方の回転センサ（図中下段の右クローラ回転センサ３）では、第二相目は、基準となる第一相よりも早期に検出する構成となっており、第一相の波形の立上りを検出した時点（Ｔ１）では、位相のずれによって第二相の波形のピークを検出し難く、正常状態を故障状態と誤診する恐れがある。よって、この場合前記主変速センサ８ａが、後進位置を検出したときに前記片側の左クローラ回転センサ３に替わって故障診断処理を行う構成となっている。
【００５６】
そして前記ＳＴＥＰ５で、センサ３の故障が検出されたときには、ＳＴＥＰ６へ進み、前記フィードバック制御での図１中のポイントｂやポイントｄで行う補正、即ち比例圧力制御弁９１への通電量の補正において設定よりも操向半径が大きくなる側への補正を牽制し、続けてＳＴＥＰ７でシステム異常ランプを点滅する。
【００５７】
これにより、センサ３，３に故障が生じても、走行を確保しつつ、トラクタＴが大回りして障害物を回避損ねることが無くなりトラクタＴの安全性を確保することができる。
また、二つの検出部３ａ，３ｂにより得られるパルス数を比較して同じパルス数を検出しているかによって、正常と故障を判定するものであるから正確にセンサ３の故障を検出することができる。
【００５８】
次に、この発明の請求項２に係る実施例について説明する。尚、共通の構成及び制御については上記例と同様であるので、説明を省略する。
この請求項２に係る発明は、前記センサ３の故障時のフィードバック制御に代わって実行される処理であり、前記コントローラ６のＥＥＰＲＯＭに、図２に示すように、ステアリングハンドル４の操作量に応じた比例圧力制御弁９１のソレノイド９１ｓへの通電量、即ちクラッチの昇圧カーブ（Ｘ）を予め設定しておく。この昇圧カーブＸは、主に路上走行を想定した場合に前記無段変速装置の出力回転が無回転若しくは逆転域に達しない程度のクラッチ圧に留められている。
【００５９】
そして、前記図１３のＳＴＥＰ２またはＳＴＥＰ５の判定にて、回転センサ３，３の故障を検出したときに、前記カーブ（Ｘ）に基づいて前記制御弁９１のソレノイド９１ｓへ通電が為されクローラ１を駆動する。
これにより、回転センサ３，３に故障が生じても、回転センサ３，３の検出に因らない方法でクローラ１，１を駆動できるものあるから、例えば傾斜地など危険な場所で車両を停止したり、誤作動が生じることを防止し、車両の安全性を確保することができる。
【００６０】
次に前記コントローラ６が行う作業機ローリング制御について、図１５に基づき説明する。
作業機ローリング制御では、最初にＳＴＥＰ１で前記ローリング制御モード設定器２７やスロープセンサ３７等、ローリング制御に関する設定器、センサなどの状態を読み込む。そしてＳＴＥＰ２で前記ローリング制御モード設定器２７の設定状態が判定され、これに応じて各制御モードによるローリング制御が行われる。
【００６１】
詳しくは、前記「水平」モードでは、作業機Ｒが水平に維持されるようにスロープセンサ３７の検出値に基づいて、前記切替制御弁８８のソレノイド８８ａ，８８ｂへ通電が行われる（ＳＴＥＰ３）。尚、前記傾き設定器１０を操作することにより「水平」姿勢以外の任意の傾斜姿勢変更できる構成となっている
また前記「平行」モードは、作業を終えて路上で走行する時等に使用するモードであり、作業機ＲがトラクタＴと相対的に平行状態を維持するよう前記切替制御弁８８のソレノイド８８ａ，８８ｂへ通電が行われる。（ＳＴＥＰ４）。
【００６２】
また前記「手動」モードでは、前記ローリング用油圧シリンダ手動調整器３６がＯＮされた時間と方向に応じて前記切替制御弁８８のソレノイド８８ａ，８８ｂへ通電が行われ、ローリング用油圧シリンダ３４のピストンを伸縮した後固定する（ＳＴＥＰ５）。
【００６３】
そして、ここでは、ＳＴＥＰ６で前記ローリング制御中にリフトアーム角センサ３３の検出値も監視し、これが所定角度以下、具体的にはクローラ１の下面よりも下方に作業機Ｒが位置すると想定される角度以下となると、ＳＴＥＰ７にて、センサ値が正常であるかどうかを判定し、これら判定がＹＥＳの場合に、左右傾き量を、作業機Ｒの高さが低位置になるほど大きく規制する構成となっている。
【００６４】
これにより、前記ローリング制御の作動によって作業機Ｒとクローラ１の後端部が接触することを防止し、双方の破損または圃場面を荒らすことを防止する。
また前記ＳＴＥＰ７のリフトアーム角センサ３３の正常であるかどうかの判定がＮＯの場合、例えば断続的な断線状態を検出してリフトアーム角センサ３３の検出値が所定角以下となった場合は、前記規制をかけない構成となっている。
【００６５】
これにより、センサの故障等による過剰な作業機Ｒのローリングを防止し圃場を荒らさない作業を行うことができる。
【図面の簡単な説明】
【図１】請求項１に関するフィードバック制御の作用を説明する図。
【図２】請求項２に関するクラッチ昇圧カーブ。
【図３】トラクタの全体側面図。
【図４】トラクタの操縦席近傍の斜視図。
【図５】ミッションケース内部の側面図。
【図６】アクスルケース内部の展開図。
【図７】トラクタの動力伝達機構線図。
【図８】トラクタの油圧回路図。
【図９】コントローラの接続状態を示す図。
【図１０】制御全体の概要を示すフローチャート。
【図１１】変速位置毎の逆転用クラッチの昇圧カーブを示す図。
【図１２】クラッチへ送る脈動圧を示すタイムチャート。
【図１３】故障診断処理の概要を示すフローチャート
【図１４】左右回転センサの検出波形を示すタイムチャート。
【図１５】ローリング制御の概要を示すフローチャート。
【符号の説明】
１ クローラ
２ 無段変速装置
３ 回転センサ
４ ステアリングハンドル
５ ステアリング切角センサ
６ コントローラ
７Ｆ 正転用クラッチ
７Ｒ 逆転用クラッチ
９１ 比例圧力制御弁
Ｔ トラクタ
Ｒ ロータリ作業機[0001]
BACKGROUND OF THE INVENTION
The present invention relates to the configuration of a steering control device for a work vehicle, such as for agriculture, construction, and transportation, and in particular, the number of rotations of traveling devices such as left and right wheels and crawlers according to the operation amount of a steering handle, a steering lever, etc. This can be used for controlling the rotation speed ratio to be set in advance.
[0002]
[Prior art]
In the Japanese Patent Application No. 2001-207979, the applicant of the present invention is that each of the left and right traveling devices and the left and right shifting the rotational speed of the traveling device from the set rotational speed to the stop and reverse rotation according to the energization amount to the solenoid valve. While equipped with a continuously variable transmission and left and right rotation sensors that detect the output rotational speed of the continuously variable transmission with the number of gear pulses, the steering operation section of the vehicle detects the operation amount of the operation section. Operation amount detecting means is provided, and when the operation amount of the steering operation unit exceeds a set amount, the rotation speed of the left and right traveling devices becomes a preset rotation speed ratio according to the operation amount of the steering operation unit. An application has been filed for a work vehicle provided with control means for correcting the energization amount to the solenoid valve.
[0003]
[Problems to be solved by the invention]
However, when the work vehicle is driven in a place with severe unevenness or in a poor environment where dirt or mud easily adheres, electrical parts are particularly likely to fail, and if such a failure occurs, ensuring the safety of the vehicle At the same time, it is desirable to have a configuration that enables a minimum movement and prepares for repair and maintenance.
[0004]
In the rotation sensor, when detecting the number of pulses obtained according to the rotation of the detection gear, the rotation (voltage) change in a normal state, a change due to simple noise, and the case of failure such as disconnection Since the detected waveforms are similar, there is a problem that it is difficult to accurately diagnose the failure.
[0005]
[Means to solve the problem]
In view of the above problems, the present invention is configured as follows in a steering control device for a work vehicle.
That is, in the work vehicle according to the first aspect, the left and right traveling devices (1, 1) and the rotational speed of the traveling device (1, 1) are set according to the energization amount to the solenoid valve (91). The left and right continuously variable transmissions (2, 2) that shift to stop and reverse, and the left and right rotation sensors (3, 3) that detect the output rotational speed of the continuously variable transmission (2) by the number of gear pulses. ), The steering operation section (4) of the vehicle is provided with an operation amount detection means (5) for detecting the operation amount of the operation section (4), and the steering operation section ( 4) Control means (6) for correcting the energization amount to the solenoid valve (91) so that the rotational speed of the left and right traveling device (1, 1) becomes a preset rotational speed ratio according to the operation amount of 4). The configuration.
(Operation of claim 1)
The control means (6) performs failure diagnosis of the sensor (3, 3) when the vehicle is not steered, and when the failure of the sensor (3, 3) is detected by the diagnosis, In the correction of the energization amount to the solenoid valve (91), the correction to the side where the steering radius is increased is suppressed.
[0008]
【The invention's effect】
Thus, according to the first aspect of the present invention, even if a failure occurs in the rotation sensor (3, 3), the vehicle does not rotate so much as to avoid obstacles and the safety of the vehicle can be ensured.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the case where this invention is mounted on a crawler tractor will be described.
First, the overall configuration of the tractor T will be described.
As shown in FIG. 3, the tractor T is provided with an engine mounting frame 15 at the front of the vehicle body, an engine 11 as a prime mover mounted on the frame 15, and an engine rotation output shaft 14 protruding from the rear of the engine 11; The structure is such that the rotation of the coaxial 14 is transmitted to a transmission in a cast mission case 12 (front mission case 12a, mid mission case 12b, rear mission case 12c) arranged in the longitudinal direction of the vehicle body. Further, the rotational power decelerated appropriately by various transmissions is transmitted to the crawler 1 serving as a left and right traveling device via a pinion gear 16 and a bevel gear 17 described later, a sprocket shaft 19 in the left and right axle case 18, and the like. ing.
[0011]
Above the transmission case 12, the floor 20 is supported, and on the floor 20, a steering handle 4 serving as a steering operation unit, a cockpit 21 and a position lever 22 for adjusting the height of the work implement R, The main transmission lever 23a, the auxiliary transmission lever 23b, the brake pedal 24, the clutch pedal 9, and the like are provided.
[0012]
Also, a main transmission sensor 8a and a sub transmission sensor 8b are provided as means for detecting a shift position at the rotation base of the main transmission lever 23a and the sub transmission lever 23b, and indirectly from the positions of the levers 23a and 23b. In addition, the vehicle speed is detected. The vehicle speed may be detected by a Doppler type ground sensor or a drive shaft rotation sensor, or may be detected in consideration of the throttle position of the engine 11.
[0013]
Further, fenders 25 that cover the top of the crawler 1 are provided on both the left and right sides of the floor 20.
Here, the fender 25 will be described with reference to FIG. The left and right fenders 25 are provided with hand catchers 26 and 26 for getting on and off, and a switch box 39 that can be changed depending on the contents of control is attached in front of the hand catcher 26 on one side. As a result, various controls according to the type of tractor T, for example, when adding a front loader work machine, etc., share mounting holes and fixtures, reduce production processing and the number of parts, and reduce improvement costs can do.
[0014]
Here, a switch box 39 relating to work machine rolling control, which will be described later, is provided. This switch box 39 includes a rolling control mode setting unit 27 having “auto”, “parallel”, and “manual” modes, and the “manual”. "Rolling hydraulic cylinder manual adjuster 36 that changes the length of the hydraulic cylinder 34 for rolling and arbitrarily adjusts the inclination of the working machine R in the" automatic "mode, and the left and right rolling angles of the working machine that is maintained in the" automatic "mode. An inclination setting device 10 to be adjusted is provided.
[0015]
Further, a slope sensor 37 that detects the inclination angle of the vehicle body, a rolling control sensitivity setting device 29 that switches sensitivity in two stages depending on the connection state of the coupler, and the like are provided below and behind the cockpit 21.
Further, a lifting hydraulic cylinder 30 serving as a working machine lifting actuator is provided on the upper surface of the rear mission case 12C, and a lift arm 31 connected to the piston of the cylinder 30 is rotated up and down to link it through a link mechanism. The work machine R is lifted and lowered. 3 is a lift arm angle sensor 33 provided at the rotation base of the lift arm 31, and is configured to indirectly detect the height of the work implement R.
[0016]
Further, in the type having the rolling control as described above, a rolling hydraulic cylinder 34 is attached as a work machine rolling actuator to a part of the link mechanism, and the operation amount is detected by the stalk sensor 35 provided in the cylinder 34. It has a configuration.
[0017]
Next, the power transmission structure of the tractor T will be described with reference to FIGS.
Rotational power input from the engine output shaft 14 into the front mission case 12a is first transmitted to the lower part of the case by the reduction gear 40 and transmitted to the rear main clutch 41, and provided at the front of the case 12a. It is transmitted to the hydraulic pump 42.
[0018]
The power that is turned on and off by the main clutch 41 is appropriately decelerated by the main transmission 43 and the sub-transmission 44 in the mid-transmission case 12b, and is transmitted to the sub-transmission output shaft 45 having the pinion gear 16 described later. The
The main changing device 43 is a so-called key shift transmission, and changes between “1st speed” to “3rd speed” and 1-speed reverse “1st speed” between the main transmission drive shaft 46 and the main transmission driven shaft 47. Gear sets are provided, and power is transmitted through any one of the gear sets by operating the slide keys 48 provided in the main transmission driven shaft 47 forward and backward.
[0019]
The auxiliary transmission 44 is a constant mesh gear type transmission, and an auxiliary transmission drive shaft 49 is rotatably provided on the extension of the main transmission drive shaft 46, and a “low” speed gear 50 is provided on the coaxial 49. On the other hand, an auxiliary transmission output shaft 45 having a pinion gear 16 is provided on the extension of the main transmission driven shaft 47 and meshed with the "high speed" direct connection gear and the "low" speed gear 50 on the same axis 45. A slide gear 55 having a “low” speed driven gear is provided.
[0020]
As a result, the main and auxiliary transmissions 43 and 44 can be combined to obtain the sixth forward speed from “low 1” to “high 3” and the second reverse speed of “low” and “high”.
Note that reference numeral 51 in FIG. 5 indicates a transmission gear set that transmits power to the front wheels when the tractor T is configured as a four-wheel drive type, and is configured to be permanently installed in the vehicle body.
[0021]
Further, a filter 52 is provided at the front lower portion of the front transmission case 12a so as to extend from the front surface of the case 12a to the rear of the main clutch 41, and the working machine lifting / lowering hydraulic cylinder 30, the rolling hydraulic cylinder 34, and a reverse rotation described later. The pressure oil sent to the clutches 7R and 7R is filtered. Thereby, it is possible to suck clean oil without being influenced as much as possible by the bubbles generated by the rotation of the main clutch 41 and the like.
[0022]
Further, when the tractor T is configured as a four-wheel drive type, the attachment hole 54 of the filter 52 uses an opening hole 56 through which the front wheel drive shaft is inserted and supported.
Next, based on FIG. 6, the power transmission structure of the crawler 1 which becomes a traveling device of the tractor T will be described.
[0023]
The rear portion of the rear mission case 12c is formed with inner walls 12 and 12 at a predetermined distance from the left and right side surfaces, and space portions S and S are formed between the inner side surfaces of the axle case 18 and the transmission. The pinion gear 16 at the rear end portion of the auxiliary transmission output shaft 45 is arranged at a substantially central position in the left and right width in the case 2c. A bevel gear 17 that meshes with the pinion gear 16 is provided at a substantially central position of the support shaft 61 supported by the left and right inner walls 60, 60, and one side portion of the support shaft 61 (located in the right space S in FIG. 6). The brake device 62 having a brake disk 62a, a pressure plate 62b, and the like is provided at a location) so as to protrude outward from the inner wall 60.
[0024]
The inner wall 60 may be formed of a member different from the transmission case, for example, a metal member and attached to the case.
Further, the brake device 62 rotates the brake operation shaft 62c penetrating into the space S by depressing the brake pedal 24, and between the cam groove portion of the pressure plate 62b and the inner side surface of the axle case 18. The brake ball 62d abutting and housed is moved to the inner side of the pressure plate 62b to press the brake disc 62a and brake the rotation of the support shaft 61, that is, the rotation of the left and right crawlers 1.
[0025]
On the other hand, the other end portion of the support shaft 61 (location located in the left space portion S in FIG. 6) is also projected outward from the inner wall 60, and this tip portion is connected to the connecting surface of the axle case 18. Bearings are provided in the opening support holes 63 via bearings 64, and a transmission gear 66 for transmitting power to the first drive shaft 65 of the axle case 18 is provided in the space S surrounded by the inner wall 60. Yes. The first drive shafts 65 and 65 in the left and right axle cases 18 and 18 are connected on the same shaft core by a coupling 67 in the transmission case 12c, and are always meshed with the gear 66 below the transmission gear 66. A matched transmission gear 68 is provided.
[0026]
In the configuration of the rear portion of the rear mission case 12c of the tractor T configured as described above, there is no need to provide transmission gears and brake devices on the left and right sides, respectively, and the number of parts related to these can be reduced, thereby reducing the production cost. . Further, a disc type brake device 62 is configured between the right inner wall 60 and the axle case 18, and the contact portion of the brake disc 62 a is also used as the support wall of the support shaft 61 and also makes contact with the brake ball 62 a. Since no additional members are required, the tractor T can be downsized by narrowing the left and right width of the mission case 2 as much as possible.
[0027]
Next, the continuously variable transmission 2 located on the power lower side of the first drive shaft 65 will be described.
Each of the left and right axle cases 18 is provided with a wet multi-plate reverse clutch 7R (inside the vehicle body) and a forward clutch 7F (outside the vehicle body) on the first drive shaft 65. A so-called two-stage planetary gear mechanism 71 having a counter planetary gear 70 is provided outside the clutch 7F.
[0028]
The forward rotation clutch 7F is configured to be constantly pressure-bonded by a disc spring 72. In this state, the drive-side sun gear 73 integrated with the drive-side disk 7Fa of the forward-rotation clutch 7F and the planetary gears 74 meshing with the drive-side sun gear 73, 70 and the drive-side disk 7Fb and the integrated carrier 75 are configured to rotate integrally around the drive-side sun gear 73.
[0029]
As a result, the rotation of the drive-side sun gear 73, that is, the bevel gear 17, is transmitted to the driven-side sun gear 76 at a rotation speed ratio of 1: 1.
Further, when pressure oil is fed into the cylinder chamber 77 of the reverse clutch 7R, the disk compression state of the forward rotation clutch 7F is gradually released via the connecting bolt 57, and the driving side disk 7Fa and the driven side disk 7Fb are released. A rotation difference is generated between them and the rotation transmitted to the driven sun gear 76 is reduced accordingly.
[0030]
Further, when pressure oil is further fed into the cylinder chamber 77 and the movement amount of the piston is increased to the inside of the vehicle body, the disk compression state of the forward rotation clutch 7F is completely released and the rotation of the driven sun gear 76 is zero. After that, the drive side disk 7Ra and the driven side disk 7Rb of the reverse rotation clutch 7R fixed to the axle case 18 side are gradually pressure-bonded, and the rotation of the first drive shaft 65 causes the two-stage planetary gear mechanism 71 to move. To the driven sun gear 76 via the reverse rotation.
[0031]
As a result, the piston of the clutch 7R is moved in one direction in response to an energization command from the controller 6, which will be described later, so that the rotation of the bevel gear 17, that is, the rotation to the crawler 1, is gradually decelerated and transmitted. The speed is gradually increased by reverse rotation.
[0032]
Further, a rotation detection gear 8 integrally formed with the driven sun gear 76 is provided on the lower transmission side of the continuously variable transmission 2, and the rotation sensor 3 detects the rotation of the gear 8. . The rotation sensor 3 includes two independent detectors 3b and 3b having a predetermined interval on the circumference of the detection gear 8, and detects the waveforms of the first phase and the second phase as will be described later. It has become.
[0033]
The driven sun gear 76 is integrally assembled with a second drive shaft 78 that supports the driven sun gear 76 and a lid 79 that shields the outer open portion of the axle case 18.
The lid 79 has a dish shape having a hollow portion, and a planetary gear type reduction mechanism 81 for reducing the rotation of the second drive shaft 78 and transmitting it to the sprocket shaft 19 is housed inside the lid 79. An annular protrusion 83 that supports the inside of the sprocket 82 and protects the internal seal member is formed on the wall.
[0034]
When the lid 79 is assembled to the axle case 18 of the tractor T, the deceleration mechanism 81 is assembled with the axle case 18 covered.
Next, the hydraulic circuit of the tractor T will be described with reference to FIG.
The hydraulic pump 42 is configured to suck up the oil in the transmission case 2 by driving the engine 11 and branch the pressure oil into the work machine operation system hydraulic circuit L1 and the traveling system hydraulic circuit L2.
[0035]
The work machine operation system hydraulic circuit L1 is provided with a pressure reducing valve 86, a flow dividing valve 87, and a switching control valve 88 in this order from the upper side of the circuit. The hydraulic oil is reduced to a predetermined pressure by the pressure reducing valve 86 and is supplied to the flow dividing valve 87. Thus, only the necessary amount is sent to the working machine rolling hydraulic cylinder 34 through the switching operation of the switching control valve 88. Further, the remaining hydraulic oil diverted by the diversion valve 87 is configured to be fed into the working machine elevating hydraulic cylinder 30 via the manual switching valve 89.
[0036]
The travel system hydraulic circuit L2 is provided with a pressure reducing valve 90, and hydraulic oil is supplied from the upper side of the circuit via a proportional pressure control valve 91 and a switching control valve 92 to either the left or right piston cylinder of the reverse clutch 7R. It is configured to feed into the chamber 77.
Thereby, pressure oil is sent to the reverse rotation clutch 7R inside the turning by switching the switching control valve 92, and the energization amount to the proportional pressure control valve 91 is changed, so that the cylinder chamber 77 of the reverse rotation clutch 7R is changed. The amount of oil flowing in can be controlled to operate the clutch piston, and the rotation of the crawler 1 can be gradually decelerated from the forward rotation and switched to the reverse rotation through the stop state to increase the speed.
[0037]
Next, steering control of the tractor T will be described.
As shown in FIG. 9, the controller 6, which is the control means of the tractor T, includes a CPU for processing various signals therein, a RAM for temporarily storing various signals, and a control program serving as a restraining means / switching means of the present invention. The steering section angle sensor 5, main shift position sensor 8 a, auxiliary transmission H speed switch 8 b, spin turn on / off switch 28, left and right crawler rotation sensors 3, 3, lift arm angle Sensor 33, rolling control mode setting device 27, inclination setting device 10, rolling control hydraulic cylinder expansion / contraction adjustment device 36, rolling control sensitivity setting device 29, slope sensor 37 for detecting the left-right inclination of the vehicle body, stroke of the rolling hydraulic cylinder A sensor 35 and the like are connected.
[0038]
The output section includes a spin turn pilot lamp 29, a system abnormality alarm lamp 85, a solenoid 91s of a proportional pressure control valve for adjusting the clutch pressure, a solenoid 92s of a switching control valve for switching the left and right reverse clutch operation, and the working machine R. There are provided solenoids 88s and 88b of a switching control valve 88 for raising and lowering the right end of the motor, a horizontal mode pilot lamp 84, and a coupler 84 for connecting a portable checker. The horizontal mode pilot lamp 84 is normally lit when the rolling control mode setting unit 27 is switched to the “horizontal” mode, and the operation of the controller 6 is checked by connecting the portable checker. It is configured to be used as a check lamp.
[0039]
In the tractor T configured as described above, control is performed as shown in the flowchart of FIG.
First, when the power of the tractor T is turned on, in STEP1, the controller 6 reads the connection state of various sensors and setting devices, and in accordance with this, in STEP2, the main / sub transmission sensors 8a and 8b according to the shift position, A target set speed ratio (FIG. 11) is set. The pressure increase curve of the reverse clutch is a clutch pressure increase curve obtained when control is performed in accordance with the set rotational speed ratio. When the sub-shift position is “high”, it is more gradual than when it is “low”. It is configured to boost the voltage. Further, as shown in Table 1, even when the spin turn on / off switch 28 is turned on, the super turn (spin turn) that reverses the crawler 1 inside the turn only when the sub-shift position is at the “low” speed. In addition, if the sub-shift position is “high” and the main shift is “1” speed, it is possible to perform a pivot turn (lock turn) that stops the crawler 1 inside the turn, and the sub-shift position is “high”. If the main gear shift is “2” speed or “3” speed, the crawler 1 inside the turn is rotated slowly (hereinafter referred to as “mild turn”). Further, even when the mild turn areas at the respective shift positions are compared, the clutch pressure at the initial stage of the steering operation is suddenly increased and the vehicle body is turned sharply as the vehicle speed becomes “low”.
[0040]
[Table 1]

[0041]
Then, the controller 6 determines the steering amount of the vehicle based on the detection of the steering angle sensor 5 in STEP 3, and if this exceeds a predetermined amount, it determines that the vehicle body is in the steering state, and is preset in STEP 4. The feedback control for shifting the left and right crawler rotation with the correction value of the correction table is executed.
[0042]
In the feedback control, the rotation speed ratio of the crawler 1 on the inside of the turn with respect to the rotation of the crawler 1 on the turn outside is calculated from the rotation speeds of the left and right crawlers 1 and 1, and a predetermined correction value is set so as to match the set rotation speed ratio. Based on the determined table, the clutch pressure, that is, the energization amount to the solenoid 91s of the proportional pressure control valve 91 is corrected.
[0043]
Further, as will be described later, the correction value is set to be smaller as the set rotational speed ratio is closer to 0, that is, as the crawler 1 inside the turn is stopped, and the corrected rotational speed ratio is The larger the difference from the set rotational speed ratio, the larger the correction amount (clutch pressure) is set. The correction is repeatedly executed and periodically added to the detected clutch pressure. (1) When the steering handle 4 is returned to the straight drive position, (2) the shift position is changed. When (3) the spin turn on / off switch 28 is “ON”, when the spin turn area is reached, the clearing is started and a new correction is started.
[0044]
For example, as shown in FIG. 1, in a state where the shift position is set to “low 2” and the spin turn is set to “on”, a set rotation speed ratio of Lb is set. Here, when the steering handle 4 is turned, the reverse rotation clutch 7R on the inner side of the turn is boosted so as to achieve the rotation ratio of FIG.
[0045]
At this set speed ratio Lb, there is a play area within about 20 ° in the initial stage of the steering operation, and then the reverse rotation clutch 7R is boosted more rapidly than when the sub-shift position is “high” (see FIG. 11). When the steering handle 4 is further turned and exceeds about 120 ° on the left and right, the disks 7Fa and 7Fb of the forward clutch 7F inside the turning are completely released, the crawler 1 is stopped, and a lock turn state is entered. When the steering wheel 4 continues to be turned and exceeds about 150 °, the clutch pressure is rapidly increased, the reverse clutch 7R is pressure-bonded, and the crawler 1 on the inner side of the turn is reversely rotated to be in a spin turn state. In the feedback control in the steering control, the correction value based on the table is repeatedly added.
[0046]
The characteristics of this correction will be further described with reference to FIG. 1. For example, when the steering angle is about 90 °, the set rotational speed ratio is set to about 0.5. At this time, if the difference between the detected rotational speed ratio and the set rotational speed ratio is a plus side (point a), the tractor T is in a state of greater rotation than expected, so this is set in the table so as to approach the set rotational speed ratio. Based on the corrected amount, the clutch pressure is corrected to the plus side. This correction amount is set to be larger as the difference is larger.
[0047]
Similarly, if the steering angle is about 90 ° and the difference between the detected rotational speed ratio and the set rotational speed ratio is on the negative side (point b), the tractor T is in a smaller turning state than the set value, so the clutch pressure is negative. Correct to the side. The difference from the set speed ratio Lb at the point b is the same absolute amount as the difference at the point a, but the correction amount is set to be larger than the positive correction amount.
[0048]
For example, when the steering angle is about 100 °, the set rotational speed ratio is set to about 0.4. At this time, if the difference between the detected rotational speed ratio and the set rotational speed ratio is on the plus side (point c), the tractor T is in a large-rotation state, so that the clutch pressure is set based on the table to bring this close to the set rotational speed ratio. Correct to the plus side. This correction amount is set to a smaller value than the same difference when the steering angle is 90 °. On the other hand, if the difference between the detected rotational speed ratio and the set rotational speed ratio is negative (point d), the tractor T is in a state of turning less than the setting, so that this is made closer to the set rotational speed ratio based on the table. Correct the clutch pressure to the negative side. As described above, the correction amount on the minor side is set larger than the correction amount on the plus side even if the absolute amount of the difference between the detected rotation speed and the set rotation speed is the same.
[0049]
In addition, as shown in FIG. 12, the clutch pressure periodically applies pulsation pressure (P3) to maintain the holding pressure (P2) even when there is no correction or steering operation, and maintains the rotation speed of the crawler 1. It has a configuration. Reference sign P1 in the figure indicates an initial pressure that is initially applied when the correction or steering operation is maintained. In the figure, times T1, T2, and T3 indicate the duration of each pressure, and have a relationship of T1>T2> T3.
[0050]
The set rotational speed ratio is obtained from experiments based on the specifications of the clutches 7F and 7R, the model of the tractor T, and the like. The set rotational speed ratio and the correction amount are determined by the portable checker 95. It can be changed. Since there are individual differences in the reverse clutch 7R, various hydraulic devices, etc., the correction table is set separately for the left and right, or set for each turning region, that is, for each of the mild turn region, the lock turn region, and the spin turn region. Also good. Furthermore, the boost curve may be set for each shift position, and the boost curve may be set more gradually as the shift position is set to a higher speed as described above.
[0051]
In the steering control device for the tractor T configured as described above, the left and right steering amounts of the vehicle are detected, and the output rotational speeds of the continuously variable transmissions 2 and 2 are appropriately set so as to obtain a set rotational speed ratio corresponding to the steering amount. Since the correction at this time repeatedly adds a predetermined correction amount to the driving state at the time of detection, the rotation speed of the crawlers 1 and 1 gradually approaches the set rotation speed ratio.
[0052]
Thereby, since the driving force of the crawlers 1 and 1 does not change greatly, smooth steering can be performed.
Further, when the continuously variable transmission 2 has a wet multi-plate reverse clutch 7R, the difference due to characteristics such as a difference in operating force and a time difference between the direction in which the clutch plate is crimped and the direction in which the clutch plate is released is reduced. Compared with the configuration in which a uniform correction amount is added, smooth and quick feedback control can be performed, and smooth steering can be performed.
[0053]
On the other hand, if it is determined in STEP 3 that the vehicle body is not in the steering state, the process proceeds to STEP 5 where energization of the solenoid 91s of the proportional pressure control valve 91 is stopped, and a failure diagnosis process for the rotation sensor 3 is performed in STEP 6. Do.
In this failure diagnosis process, as shown in FIG. 13, first, in STEP 1, a failure diagnosis of the first phase of the detection unit is performed. Here, the first phase is for detecting the gear rotation speed, i.e., the rotation speed of the crawler 1, and is different from the number of detected waveforms of the first phases of the left and right rotation sensors 3 and 3 within a predetermined time. Determine whether there is
When the difference exceeds a predetermined number of times, it is determined that there is a failure (STEP 2). If this is YES, the system abnormality alarm lamp 85 is turned on at STEP 3.
[0054]
If there is no abnormality in STEP2, the process proceeds to STEP4. If the rotating lamp 85 is lit, the lamp is turned off.
In STEP 5, a failure diagnosis of the second phase of the rotation sensor 3 is performed. Referring to FIG. 14, when the first phase waveform rises (T1) in one rotation sensor (upper left crawler rotation sensor 3 in the figure), the second phase waveform is compared, that is, the waveform. Is detected as normal, and it is determined as a failure when a predetermined number of peaks or more are not detected in the number of gear pulses corresponding to one rotation of the rotation detecting gear 8.
[0055]
In the other rotation sensor (the right crawler rotation sensor 3 in the lower part of the figure), the second phase is detected earlier than the reference first phase, and the rising of the waveform of the first phase At the time of detecting (T1), it is difficult to detect the peak of the waveform of the second phase due to the phase shift, and there is a possibility that the normal state is misdiagnosed as a failure state. Therefore, in this case, the main transmission sensor 8a performs a failure diagnosis process in place of the left crawler rotation sensor 3 on one side when detecting the reverse position.
[0056]
When a failure of the sensor 3 is detected in STEP 5, the process proceeds to STEP 6, and correction performed at the point b and point d in FIG. 1 in the feedback control, that is, correction of the energization amount to the proportional pressure control valve 91 is performed. The correction to the side where the steering radius becomes larger than the setting is checked, and then the system abnormality lamp blinks in STEP7.
[0057]
Thereby, even if a failure occurs in the sensors 3 and 3, the tractor T does not rotate around and avoids obstacles while securing traveling, and the safety of the tractor T can be ensured.
In addition, it is possible to accurately detect the failure of the sensor 3 because the normality and the failure are determined depending on whether the same number of pulses is detected by comparing the number of pulses obtained by the two detection units 3a and 3b. .
[0058]
Next, an embodiment according to claim 2 of the present invention will be described. In addition, since it is the same as that of the said example about common structure and control, description is abbreviate | omitted.
The invention according to claim 2 is a process executed in place of the feedback control at the time of failure of the sensor 3, and the EEPROM of the controller 6 corresponds to the operation amount of the steering handle 4 as shown in FIG. 2. The energization amount to the solenoid 91s of the proportional pressure control valve 91, that is, the clutch pressure-up curve (X) is set in advance. The pressure-up curve X is kept at a clutch pressure such that the output rotation of the continuously variable transmission does not reach the non-rotation or reverse rotation region when driving on the road is mainly assumed.
[0059]
Then, when the failure of the rotation sensors 3 and 3 is detected in the determination of STEP2 or STEP5 in FIG. 13, the solenoid 91s of the control valve 91 is energized based on the curve (X), and the crawler 1 is turned on. To drive.
As a result, even if a failure occurs in the rotation sensors 3 and 3, the crawlers 1 and 1 can be driven by a method that does not depend on the detection of the rotation sensors 3 and 3, so that the vehicle is stopped at a dangerous place such as an inclined land. Or malfunction can be prevented, and the safety of the vehicle can be ensured.
[0060]
Next, work implement rolling control performed by the controller 6 will be described with reference to FIG.
In the work machine rolling control, first, in STEP 1, the states of the rolling control mode setting unit 27, the slope sensor 37, and the like, setting units and sensors related to rolling control are read. In STEP 2, the setting state of the rolling control mode setting unit 27 is determined, and rolling control in each control mode is performed accordingly.
[0061]
Specifically, in the “horizontal” mode, the solenoids 88a and 88b of the switching control valve 88 are energized based on the detection value of the slope sensor 37 so that the work implement R is maintained horizontal (STEP 3). It should be noted that any tilt posture other than the “horizontal” posture can be changed by operating the tilt setting device 10.
Further, the “parallel” mode is a mode used when, for example, the vehicle travels on the road after finishing the work, and the solenoid 88a, Power is supplied to 88b. (STEP4).
[0062]
In the “manual” mode, the solenoids 88 a and 88 b of the switching control valve 88 are energized according to the time and direction in which the rolling hydraulic cylinder manual adjuster 36 is turned on, and the piston of the rolling hydraulic cylinder 34 is energized. Is fixed after expanding and contracting (STEP 5).
[0063]
Here, the detected value of the lift arm angle sensor 33 is also monitored during the rolling control in STEP 6, and it is assumed that this is below a predetermined angle, specifically, the work implement R is located below the lower surface of the crawler 1. When the angle is less than or equal to the angle, in STEP 7, it is determined whether or not the sensor value is normal, and when these determinations are YES, the amount of left-right inclination is greatly restricted as the height of the work implement R is lowered. It has become.
[0064]
Thereby, it is prevented that the working machine R and the rear end portion of the crawler 1 come into contact with each other by the operation of the rolling control, and both of them are prevented from being damaged or being damaged.
If the determination of whether or not the lift arm angle sensor 33 in STEP 7 is normal is NO, for example, when an intermittent disconnection state is detected and the detection value of the lift arm angle sensor 33 falls below a predetermined angle, It is the structure which does not apply the said regulation.
[0065]
Thereby, it is possible to perform an operation that prevents excessive rolling of the work machine R due to a sensor failure or the like and does not roughen the field.
[Brief description of the drawings]
FIG. 1 is a diagram for explaining the operation of feedback control according to claim 1;
FIG. 2 is a clutch boost curve according to claim 2;
FIG. 3 is an overall side view of the tractor.
FIG. 4 is a perspective view of the vicinity of the cockpit of the tractor.
FIG. 5 is a side view of the inside of the mission case.
FIG. 6 is a development view inside the axle case.
FIG. 7 is a power transmission mechanism diagram of the tractor.
FIG. 8 is a hydraulic circuit diagram of the tractor.
FIG. 9 is a diagram illustrating a connection state of controllers.
FIG. 10 is a flowchart showing an overview of overall control.
FIG. 11 is a diagram showing a boost curve of a reverse clutch for each shift position.
FIG. 12 is a time chart showing the pulsation pressure sent to the clutch.
FIG. 13 is a flowchart showing an overview of failure diagnosis processing;
FIG. 14 is a time chart showing a detection waveform of a left / right rotation sensor.
FIG. 15 is a flowchart showing an outline of rolling control.
[Explanation of symbols]
1 crawler
2 continuously variable transmission
3 Rotation sensor
4 Steering handle
5 Steering angle sensor
6 Controller
7F Forward rotation clutch
7R Clutch for reverse rotation
91 Proportional pressure control valve
T tractor
R Rotary work machine

Claims (1)

  The left and right traveling devices (1, 1) and the left and right speeds of the traveling devices (1, 1) are shifted from the set number of rotations to stop and reverse according to the energization amount to the solenoid valve (91). The vehicle includes a continuously variable transmission (2, 2) and left and right rotation sensors (3, 3) for detecting the output rotational speed of the continuously variable transmission (2) by the number of gear pulses. The operation unit (4) is provided with an operation amount detection means (5) for detecting the operation amount of the operation unit (4). When the vehicle is steered, the left and right sides are controlled according to the operation amount of the steering operation unit (4). In a work vehicle having a control means (6) for correcting the energization amount to the solenoid valve (91) so that the rotation speed of the traveling device (1, 1) becomes a preset rotation speed ratio, the control means (6 ) Performs failure diagnosis of the sensor (3, 3) when the vehicle is not steered, and When a failure of the sensor (3, 3) is detected by disconnection, a check means is provided for checking the correction to the side where the steering radius becomes larger in the correction of the energization amount to the solenoid valve (91). A steering control device for a work vehicle.

Images