JP4847366B2 - Working vehicle - Google Patents

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JP4847366B2
JP4847366B2 JP2007045172A JP2007045172A JP4847366B2 JP 4847366 B2 JP4847366 B2 JP 4847366B2 JP 2007045172 A JP2007045172 A JP 2007045172A JP 2007045172 A JP2007045172 A JP 2007045172A JP 4847366 B2 JP4847366 B2 JP 4847366B2
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transmission path
power transmission
hydraulic
hydraulic clutch
wheel
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JP2008207648A (en
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博行 有田
秀雄 実重
真一 小山
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MITSUBISHI NOUKI KABUSHIKI KAISHA
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MITSUBISHI NOUKI KABUSHIKI KAISHA
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Description

本発明は、トラクタなどの作業用走行車に関し、特に、前輪動力伝動経路に、等速動力伝動経路と増速動力伝動経路を並列に構成すると共に、各伝動経路に介設した油圧クラッチの選択的な入り/切りにより、2輪駆動状態、4輪駆動状態及び前輪増速駆動状態を現出させる作業用走行車に関する。   The present invention relates to a working vehicle such as a tractor, and in particular, a constant speed power transmission path and a speed increasing power transmission path are configured in parallel to a front wheel power transmission path, and a hydraulic clutch provided in each transmission path is selected. The present invention relates to a working vehicle that makes a two-wheel drive state, a four-wheel drive state, and a front-wheel acceleration drive state appear by turning on and off.

前輪動力伝動経路に、等速動力伝動経路と増速動力伝動経路を並列に構成すると共に、各伝動経路に介設した油圧クラッチの選択的な入り/切りにより、2輪駆動状態、4輪駆動状態及び前輪増速駆動状態を現出させる作業用走行車が知られている(例えば、特許文献1参照)。この種の作業用走行車では、通常、図7に示すように、等速動力伝動経路の油圧クラッチ101をスプリング作動型油圧クラッチ(ネガティブ油圧クラッチ)とする一方、増速動力伝動経路の油圧クラッチ102を油圧作動型油圧クラッチ(ポジティブ油圧クラッチ)とし、これらの油圧クラッチ101、102を3位置切換弁103で選択的に入り/切りさせることにより、前輪を駆動させない2輪駆動状態と、前輪を後輪と略等速で駆動させる4輪駆動状態と、前輪を後輪よりも増速駆動させる前輪増速駆動状態とを現出させるようになっている。
特開2000−52799号公報
A constant speed power transmission path and a speed increasing power transmission path are configured in parallel with the front wheel power transmission path, and a two-wheel drive state and a four-wheel drive are performed by selectively turning on / off a hydraulic clutch interposed in each transmission path. 2. Description of the Related Art A working vehicle that reveals a state and a front wheel acceleration drive state is known (see, for example, Patent Document 1). In this type of working vehicle, as shown in FIG. 7, the hydraulic clutch 101 of the constant speed power transmission path is normally a spring-actuated hydraulic clutch (negative hydraulic clutch), while the hydraulic clutch of the speed increasing power transmission path is used. 102 is a hydraulically actuated hydraulic clutch (positive hydraulic clutch), and these hydraulic clutches 101 and 102 are selectively turned on and off by a three-position switching valve 103, whereby a two-wheel drive state in which the front wheels are not driven, A four-wheel drive state in which the rear wheel is driven at a substantially constant speed and a front wheel acceleration drive state in which the front wheel is driven at a higher speed than the rear wheel are made to appear.
JP 2000-52799 A

ところで、上記従来の作業用走行車では、4輪駆動状態(油圧クラッチ101=入り、油圧クラッチ102=切り)から前輪増速駆動状態(油圧クラッチ101=切り、油圧クラッチ102=入り)に切換える場合に、3位置切換弁103を前輪増速位置に切換え、油圧ポンプ104からの圧油を二つの油圧クラッチ101、102に同時供給することになるが、油圧クラッチ101、102のピストン室は、部品精度のバラツキによりリーク量が個々に異なるため、実際には二つの油圧クラッチ101、102を同時に作動させることは困難であり、最悪の場合は、二つの油圧クラッチ101、102が同時に入りとなり、摩擦プレートの焼き付きが発生する惧れがあった。   By the way, in the conventional working vehicle, when switching from the four-wheel drive state (hydraulic clutch 101 = engaged, hydraulic clutch 102 = disengaged) to the front wheel acceleration drive state (hydraulic clutch 101 = disengaged, hydraulic clutch 102 = engaged). In addition, the three-position switching valve 103 is switched to the front wheel acceleration position, and the pressure oil from the hydraulic pump 104 is supplied to the two hydraulic clutches 101 and 102 simultaneously. In actuality, it is difficult to operate the two hydraulic clutches 101 and 102 at the same time because the leak amount differs depending on the accuracy variation. In the worst case, the two hydraulic clutches 101 and 102 are simultaneously engaged, and friction is caused. There was a risk of burning of the plate.

本発明は、上記の如き実情に鑑みこれらの課題を解決することを目的として創作されたものであって、請求項1の発明は、前輪動力伝動経路に、後輪動力と略等速の動力を前輪に伝動する等速動力伝動経路と、後輪動力よりも増速された動力を前輪に伝動する増速動力伝動経路とを並列に構成すると共に、等速動力伝動経路には、スプリングの付勢力で入り状態となり、油圧供給により切り状態となるスプリング作動型油圧クラッチを介設する一方、増速動力伝動経路には、スプリングの付勢力で切り状態となり、油圧供給により入り状態となる油圧作動型油圧クラッチを介設し、これらの油圧クラッチの選択的な入り/切りにより、前輪を駆動させない2輪駆動状態と、前輪を後輪と略等速で駆動させる4輪駆動状態と、前輪を後輪よりも増速駆動させる前輪増速駆動状態とを現出させる作業用走行車において、前記等速動力伝動経路のスプリング作動型油圧クラッチを入り/切りさせる第一の2位置切換弁と、前記増速動力伝動経路の油圧作動型油圧クラッチを入り/切りさせる第二の2位置切換弁とを別個に備えるにあたり、前記第一、第二の2位置切換弁を、油圧ポンプから油圧作動型油圧クラッチに至る供給油路に直列に介在させて、該油圧作動型油圧クラッチの入り作動を第一、第二の2位置切換弁の入り側への単独切換では禁止するように構成したことを特徴とする作業用走行車である。このようにすると、等速動力伝動経路のスプリング作動型油圧クラッチを入り/切りさせるタイミングと、増速動力伝動経路の油圧作動型油圧クラッチを入り/切りさせるタイミングを個別に制御することができるので、二つの油圧クラッチを適正なタイミングで入り/切りさせ、駆動状態の切換えを円滑に行うことができる。
請求項2の発明は、4輪駆動状態から前輪増速駆動状態に切換えるとき、前記等速動力伝動経路のスプリング作動型油圧クラッチを切りにするタイミングに対し、前記増速動力伝動経路の油圧作動型油圧クラッチを入りにするタイミングを遅延させることを特徴とする請求項1記載の作業用走行車である。このようにすると、4輪駆動状態から前輪増速駆動状態への切換えに際し、等速動力伝動経路のスプリング作動型油圧クラッチと、増速動力伝動経路の油圧作動型油圧クラッチが同時に入りとなることを確実に回避し、摩擦プレートの焼き付きを防止することができる。
The present invention has been created in view of the above circumstances and has been created for the purpose of solving these problems, and the invention of claim 1 is directed to a front wheel power transmission path with a rear wheel power and a substantially constant power. The constant speed power transmission path for transmitting the power to the front wheels and the increased speed power transmission path for transmitting the power increased from the rear wheel power to the front wheels are configured in parallel. A spring-actuated hydraulic clutch that is turned on by the urging force and turned off when the hydraulic pressure is supplied is interposed. On the speed increasing power transmission path, the hydraulic pressure that is turned on by the urging force of the spring and turned on when the hydraulic pressure is supplied. A two-wheel drive state in which an actuated hydraulic clutch is interposed, and the front wheels are not driven by selective on / off of these hydraulic clutches, a four-wheel drive state in which the front wheels are driven at substantially the same speed as the rear wheels, and the front wheels Than the rear wheel In working vehicle for revealing the front-wheel acceleration drive state to speed drive, a first 2-position switching valve for On / Off spring-actuated hydraulic clutches of the constant velocity power transmission path, the speed increasing power transmission When separately providing a second two-position switching valve for turning on / off the hydraulically operated hydraulic clutch of the path, the first and second two-position switching valves are supplied from the hydraulic pump to the hydraulically operated hydraulic clutch. For working, characterized in that it is interposed in series in the oil passage so that the operation of engaging the hydraulically operated hydraulic clutch is prohibited when the first and second two-position switching valves are individually switched to the inlet side. It is a traveling car. In this way, the timing for turning on / off the spring-actuated hydraulic clutch on the constant-speed power transmission path and the timing for turning on / off the hydraulic-actuated hydraulic clutch on the speed increasing power transmission path can be individually controlled. The two hydraulic clutches can be turned on and off at appropriate timings, and the driving state can be switched smoothly.
According to a second aspect of the present invention, when the four-wheel drive state is switched from the four-wheel drive state to the front wheel acceleration drive state, the hydraulic operation of the speed increasing power transmission path is performed with respect to the timing at which the spring operated hydraulic clutch of the constant speed power transmission path is disengaged. The working vehicle according to claim 1, wherein a timing for engaging the mold hydraulic clutch is delayed. In this way, when switching from the four-wheel drive state to the front wheel acceleration drive state, the spring-actuated hydraulic clutch of the constant-speed power transmission path and the hydraulic-actuation type hydraulic clutch of the acceleration power transmission path are simultaneously engaged. Can be reliably avoided and seizure of the friction plate can be prevented.

次に、本発明の実施形態について、図面に基づいて説明する。図1及び図2において、1は農用のトラクタTに搭載されるミッションケースであって、該ミッションケース1は、主クラッチ機構2を介してエンジンEの動力を入力すると共に、入力した動力を走行動力伝動経路3とPTO動力伝動経路4とに分岐させる。走行動力伝動経路3には、複数の伝動軸S1〜S11と、4段変速の油圧クラッチ式変速機構C1、C2からなる第一の主変速機構5と、油圧クラッチ式変速機構C3からなる前後進切換機構6と、3段変速の噛み合い式変速機構Kからなる副変速機構7と、2段変速の油圧クラッチ式変速機構C4からなる第二の主変速機構8と、2段変速の油圧クラッチ式変速機構C5からなる前輪変速機構9とを備えて構成されている。本発明は、前輪変速機構9及びその油圧作動回路に特徴を有しており、以下、これらの具体的な構成について、図3〜図6を参照して説明する。   Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a transmission case mounted on an agricultural tractor T. The transmission case 1 inputs the power of the engine E through the main clutch mechanism 2 and travels the input power. The power transmission path 3 and the PTO power transmission path 4 are branched. The traveling power transmission path 3 includes a plurality of transmission shafts S1 to S11, a first main transmission mechanism 5 including four-stage hydraulic clutch transmission mechanisms C1 and C2, and a forward / rearward movement including a hydraulic clutch transmission mechanism C3. A switching mechanism 6, a sub-transmission mechanism 7 comprising a three-speed meshing transmission mechanism K, a second main transmission mechanism 8 comprising a two-speed hydraulic clutch transmission mechanism C 4, and a two-speed hydraulic clutch type A front wheel transmission mechanism 9 including a transmission mechanism C5 is provided. The present invention is characterized by the front wheel speed change mechanism 9 and its hydraulic operation circuit. Hereinafter, specific configurations thereof will be described with reference to FIGS.

図3及び図4に示すように、前輪変速機構9は、伝動軸S10と伝動軸S11との間の前輪動力伝動経路に、後輪Rの動力と略等速の動力を前輪Fに伝動する等速動力伝動経路10と、後輪Rの動力よりも増速された動力を前輪Fに伝動する増速動力伝動経路11とを並列に構成すると共に、等速動力伝動経路10には、スプリング12の付勢力で入り状態となり、油圧供給により切り状態となるスプリング作動型油圧クラッチ(ネガティブ油圧クラッチ)13を介設する一方、増速動力伝動経路11には、スプリング14の付勢力で切り状態となり、油圧供給により入り状態となる油圧作動型油圧クラッチ(ポジティブ油圧クラッチ)15を介設し、これらの油圧クラッチ13、15の選択的な入り/切りにより、前輪Fを駆動させない2輪駆動状態(油圧クラッチ13=切り、油圧クラッチ15=切り)と、前輪Fを後輪Rと略等速で駆動させる4輪駆動状態(油圧クラッチ13=入り、油圧クラッチ15=切り)と、前輪Fを後輪Rよりも増速駆動させる前輪増速駆動状態(油圧クラッチ13=切り、油圧クラッチ15=入り)とを現出させることができるようになっている。   As shown in FIGS. 3 and 4, the front wheel speed change mechanism 9 transmits the power of the rear wheel R and the power of substantially the same speed to the front wheel F on the front wheel power transmission path between the transmission shaft S10 and the transmission shaft S11. A constant speed power transmission path 10 and a speed increasing power transmission path 11 for transmitting the power increased from the power of the rear wheel R to the front wheels F are configured in parallel, and the constant speed power transmission path 10 includes a spring. A spring-actuated hydraulic clutch (negative hydraulic clutch) 13 that is turned on by an urging force of 12 and turned off by the supply of hydraulic pressure is interposed, while the motive force of the spring 14 is turned off in the speed increasing power transmission path 11. Thus, a hydraulically actuated hydraulic clutch (positive hydraulic clutch) 15 that is turned on when hydraulic pressure is supplied is interposed, and the front wheel F is not driven by selectively turning on / off these hydraulic clutches 13 and 15. Driving state (hydraulic clutch 13 = disengaged, hydraulic clutch 15 = disengaged), four-wheel driving state in which front wheel F is driven at substantially constant speed with rear wheel R (hydraulic clutch 13 = on, hydraulic clutch 15 = disengaged), front wheel The front-wheel accelerated drive state (hydraulic clutch 13 = disengaged, hydraulic clutch 15 = engaged) in which F is driven at a higher speed than the rear wheel R can be made to appear.

図4に示すように、前輪変速機構9を作動させる油圧作動回路には、油圧ポンプ16と、等速動力伝動経路10のスプリング作動型油圧クラッチ13を入り/切りさせる第一の2位置切換弁17と、増速動力伝動経路11の油圧作動型油圧クラッチ15を入り/切りさせる第二の2位置切換弁18とを備える。このようにすると、等速動力伝動経路10のスプリング作動型油圧クラッチ13を入り/切りさせるタイミングと、増速動力伝動経路11の油圧作動型油圧クラッチ15を入り/切りさせるタイミングを個別に制御することができるので、二つの油圧クラッチ13、15を適正なタイミングで入り/切りさせ、駆動状態の切換えを円滑に行うことができる。   As shown in FIG. 4, the hydraulic operation circuit for operating the front wheel transmission mechanism 9 includes a hydraulic pump 16 and a first two-position switching valve that engages / disengages the spring-actuated hydraulic clutch 13 of the constant speed power transmission path 10. 17 and a second two-position switching valve 18 for turning on and off the hydraulically operated hydraulic clutch 15 of the speed increasing power transmission path 11. In this way, the timing for turning on / off the spring-actuated hydraulic clutch 13 of the constant-speed power transmission path 10 and the timing for turning on / off the hydraulic-actuated hydraulic clutch 15 of the speed increasing power transmission path 11 are individually controlled. Therefore, the two hydraulic clutches 13 and 15 can be turned on and off at appropriate timing, and the driving state can be switched smoothly.

本実施形態では、油圧ポンプ16からスプリング作動型油圧クラッチ13に至る供給油路に第一の2位置切換弁17のみを介在させ、その切換によりスプリング作動型油圧クラッチ13を単独で入り作動させることが可能であるが、油圧ポンプ16から油圧作動型油圧クラッチ15に至る供給油路には、第一の2位置切換弁17及び第二の2位置切換弁18を直列に介在させることにより、油圧作動型油圧クラッチ15を単独で入り作動させることを禁止している。つまり、油圧作動型油圧クラッチ15を入り作動させるには、第一の2位置切換弁17及び第二の2位置切換弁18を入り側に切換えることが要求される。これにより、油圧作動型油圧クラッチ15の単独入り作動による両油圧クラッチ13、15の同時入り状態を回避し、摩擦プレートの焼き付きを防止することができる。   In the present embodiment, only the first two-position switching valve 17 is interposed in the supply oil path from the hydraulic pump 16 to the spring-operated hydraulic clutch 13, and the spring-operated hydraulic clutch 13 is independently engaged and operated by the switching. However, the first two-position switching valve 17 and the second two-position switching valve 18 are interposed in series in the supply oil path from the hydraulic pump 16 to the hydraulically operated hydraulic clutch 15, thereby providing hydraulic pressure. The actuating hydraulic clutch 15 is prohibited from being independently operated. That is, in order to engage and operate the hydraulically operated hydraulic clutch 15, it is required to switch the first two-position switching valve 17 and the second two-position switching valve 18 to the ingress side. Thereby, the simultaneous engagement state of both hydraulic clutches 13 and 15 due to the single engagement operation of the hydraulically operated hydraulic clutch 15 can be avoided, and seizure of the friction plate can be prevented.

図4に示すように、2位置切換弁17、18は、トラクタTに搭載される制御装置19によって切換え制御される。例えば、制御装置19は、前輪駆動切換ダイヤル20の切換え操作などに応じて、2位置切換弁17、18を切換制御し、2輪駆動状態、4輪駆動状態及び前輪増速駆動状態を選択的に現出させる。そして、本実施形態の制御装置19は、4輪駆動状態(油圧クラッチ13=入り、油圧クラッチ15=切り)から前輪増速駆動状態(油圧クラッチ13=切り、油圧クラッチ15=入り)に切換えるとき、等速動力伝動経路10のスプリング作動型油圧クラッチ13を切りにするタイミングに対し、増速動力伝動経路11の油圧作動型油圧クラッチ15を入りにするタイミングを遅延させるようになっている。このようにすると、4輪駆動状態から前輪増速駆動状態への切換えに際し、等速動力伝動経路10のスプリング作動型油圧クラッチ13と、増速動力伝動経路11の油圧作動型油圧クラッチ15が同時に入りとなることを確実に回避し、摩擦プレートの焼き付きを防止することができる。   As shown in FIG. 4, the two-position switching valves 17 and 18 are switched and controlled by a control device 19 mounted on the tractor T. For example, the control device 19 switches and controls the two-position switching valves 17 and 18 according to the switching operation of the front wheel drive switching dial 20 and selectively selects the two-wheel drive state, the four-wheel drive state, and the front wheel acceleration drive state. To appear. The control device 19 according to the present embodiment switches from the four-wheel drive state (hydraulic clutch 13 = engaged, hydraulic clutch 15 = disengaged) to the front wheel acceleration drive state (hydraulic clutch 13 = disengaged, hydraulic clutch 15 = entered). The timing for turning on the hydraulically actuated hydraulic clutch 15 in the speed increasing power transmission path 11 is delayed with respect to the timing for disengaging the spring actuated hydraulic clutch 13 in the constant speed power transmission path 10. In this way, when switching from the four-wheel drive state to the front wheel acceleration drive state, the spring-actuated hydraulic clutch 13 of the constant-speed power transmission path 10 and the hydraulic-actuated hydraulic clutch 15 of the acceleration power transmission path 11 are simultaneously performed. It is possible to reliably avoid entering and prevent seizure of the friction plate.

次に、制御装置19の制御手順を図6に沿って具体的に説明する。ただし、前輪駆動切換ダイヤル20が2W位置のときは、常に2輪駆動状態を現出させ、前輪駆動切換ダイヤル20が4W位置のときは、常に4輪駆動状態を現出させ、前輪駆動切換ダイヤル20が倍速位置で、かつ、非機体旋回状態のときは、4輪駆動状態を現出させ、さらに、前輪駆動切換ダイヤル20が倍速位置で、かつ、機体旋回状態のときは、前輪増速駆動状態を現出させるものとする。   Next, the control procedure of the control device 19 will be specifically described with reference to FIG. However, when the front wheel drive switching dial 20 is at the 2W position, the two-wheel drive state is always displayed, and when the front wheel drive switching dial 20 is at the 4W position, the four-wheel drive state is always displayed. When 20 is in the double speed position and in the non-aircraft turning state, the four-wheel drive state is displayed, and when the front wheel drive switching dial 20 is in the double speed position and in the airframe turning state, the front wheel acceleration drive is performed. Let the state appear.

図6に示すように、制御装置19が行う前輪駆動制御では、まず、前輪駆動切換ダイヤル20の切換え位置を判断する(S11、S12)。ここで、前輪駆動切換ダイヤル20が2W位置の場合は、第一の2位置切換弁17をON、第二の2位置切換弁18をOFFにすることにより、4輪駆動用の油圧クラッチ13及び前輪増速用の油圧クラッチ15を切りにし(S13、S14)、常に2輪駆動状態を現出させる。また、前輪駆動切換ダイヤル20が4W位置のときは、両2位置切換弁17、18をOFFにすることにより、4輪駆動用の油圧クラッチ13を入り(S16)、前輪増速用の油圧クラッチ15を切りにし(S15)、常に4輪駆動状態を現出させる。また、前輪駆動切換ダイヤル20が倍速位置のときは、機体旋回状態であるか否かを判断し(S17)、この判断結果がNOの場合は、両2位置切換弁17、18をOFFにすることにより、4輪駆動用の油圧クラッチ13を入り(S16)、前輪増速用の油圧クラッチ15を切りにし(S15)、4輪駆動状態を現出させるが、機体旋回状態である場合は、第一の2位置切換弁17をONにして4輪駆動用の油圧クラッチ13を切りにした後(S18)、所定の待ち時間の経過を待ってから(S19)、第二の2一切換弁18をONにすることにより、前輪増速用の油圧クラッチ15を入りにし(S20)、前輪増速駆動状態を現出させる。   As shown in FIG. 6, in the front wheel drive control performed by the control device 19, first, the switching position of the front wheel drive switching dial 20 is determined (S11, S12). Here, when the front wheel drive switching dial 20 is in the 2W position, the first two-position switching valve 17 is turned on and the second two-position switching valve 18 is turned off, so that the four-wheel drive hydraulic clutch 13 and The front wheel acceleration hydraulic clutch 15 is disengaged (S13, S14), and the two-wheel drive state is always displayed. When the front wheel drive switching dial 20 is in the 4W position, the two-position switching valves 17 and 18 are turned off to engage the hydraulic clutch 13 for driving the four wheels (S16), and the front wheel speed increasing hydraulic clutch. 15 is turned off (S15), and the four-wheel drive state is always displayed. When the front wheel drive switching dial 20 is in the double speed position, it is determined whether or not the vehicle is turning (S17). If the determination result is NO, the two-position switching valves 17 and 18 are turned off. Thus, the four-wheel drive hydraulic clutch 13 is engaged (S16), the front wheel acceleration hydraulic clutch 15 is disengaged (S15), and the four-wheel drive state is revealed. After turning on the first two-position switching valve 17 and disengaging the hydraulic clutch 13 for driving the four wheels (S18), after waiting for a predetermined waiting time (S19), the second two-one switching valve 18 is turned on. Is turned on, the front wheel acceleration hydraulic clutch 15 is engaged (S20), and the front wheel acceleration drive state is revealed.

叙述の如く構成された本実施形態によれば、前輪動力伝動経路に、後輪動力と略等速の動力を前輪に伝動する等速動力伝動経路10と、後輪動力よりも増速された動力を前輪に伝動する増速動力伝動経路11とを並列に構成すると共に、等速動力伝動経路10には、スプリング12の付勢力で入り状態となり、油圧供給により切り状態となるスプリング作動型油圧クラッチ13を介設する一方、増速動力伝動経路11には、スプリング14の付勢力で切り状態となり、油圧供給により入り状態となる油圧作動型油圧クラッチ15を介設し、これらの油圧クラッチ13、15の選択的な入り/切りにより、前輪Fを駆動させない2輪駆動状態と、前輪Fを後輪Rと略等速で駆動させる4輪駆動状態と、前輪Fを後輪Rよりも増速駆動させる前輪増速駆動状態とを現出させるトラクタTにおいて、等速動力伝動経路10のスプリング作動型油圧クラッチ13を入り/切りさせる第一の2位置切換弁17と、増速動力伝動経路11の油圧作動型油圧クラッチ15を入り/切りさせる第二の2位置切換弁18とを別個に備えるので、等速動力伝動経路10のスプリング作動型油圧クラッチ13を入り/切りさせるタイミングと、増速動力伝動経路11の油圧作動型油圧クラッチ15を入り/切りさせるタイミングを個別に制御することができ、その結果、二つの油圧クラッチ13、15を適正なタイミングで入り/切りさせ、駆動状態の切換えを円滑に行うことができる。   According to the present embodiment configured as described, the front wheel power transmission path has a constant speed power transmission path 10 that transmits rear wheel power and substantially constant speed power to the front wheels, and the rear wheel power is accelerated. A speed-up power transmission path 11 that transmits power to the front wheels is configured in parallel, and the constant speed power transmission path 10 is turned on by the urging force of the spring 12 and is turned off by the hydraulic pressure supply. On the other hand, the speed increasing power transmission path 11 is provided with a hydraulically actuated hydraulic clutch 15 that is turned off by the urging force of the spring 14 and is turned on when the hydraulic pressure is supplied. , 15 by selectively turning on and off, the two-wheel drive state in which the front wheel F is not driven, the four-wheel drive state in which the front wheel F is driven at substantially the same speed as the rear wheel R, and the front wheel F increased from the rear wheel R. Front wheel to drive at high speed In the tractor T that reveals the high-speed drive state, a first two-position switching valve 17 that turns on and off the spring-actuated hydraulic clutch 13 of the constant-speed power transmission path 10 and a hydraulically-actuated type of the speed increasing power transmission path 11 Since the second two-position switching valve 18 for turning on and off the hydraulic clutch 15 is separately provided, the timing for turning on and off the spring-actuated hydraulic clutch 13 of the constant speed power transmission path 10 and the speed increasing power transmission path 11 are provided. The timing at which the hydraulic clutch 15 is engaged / disengaged can be individually controlled. As a result, the two hydraulic clutches 13 and 15 can be engaged / disengaged at an appropriate timing to smoothly switch the driving state. be able to.

また、4輪駆動状態から前輪増速駆動状態に切換えるとき、等速動力伝動経路10のスプリング作動型油圧クラッチ13を切りにするタイミングに対し、増速動力伝動経路11の油圧作動型油圧クラッチ15を入りにするタイミングを遅延させるので、4輪駆動状態から前輪増速駆動状態への切換えに際し、等速動力伝動経路10のスプリング作動型油圧クラッチ13と、増速動力伝動経路11の油圧作動型油圧クラッチ15が同時に入りとなることを確実に回避し、摩擦プレートの焼き付きを防止することができる。   In addition, when switching from the four-wheel drive state to the front wheel acceleration drive state, the hydraulically operated hydraulic clutch 15 of the speed increasing power transmission path 11 with respect to the timing at which the spring operated hydraulic clutch 13 of the constant speed power transmission path 10 is turned off. Since the timing of turning on the vehicle is delayed, when switching from the four-wheel drive state to the front wheel acceleration drive state, the spring-actuated hydraulic clutch 13 of the constant speed power transmission path 10 and the hydraulic operation type of the acceleration power transmission path 11 are performed. It is possible to reliably avoid the simultaneous engagement of the hydraulic clutch 15 and prevent the friction plate from being seized.

トラクタの斜視図である。It is a perspective view of a tractor. ミッションケース内の伝動回路図である。It is a transmission circuit diagram in a mission case. 前輪変速機構の断面図である。It is sectional drawing of a front-wheel transmission mechanism. 前輪変速機構の作動回路を示す油圧回路図である。It is a hydraulic circuit diagram which shows the operation circuit of a front-wheel transmission mechanism. 前輪変速機構の制御構成を示すブロック図である。It is a block diagram which shows the control structure of a front-wheel transmission mechanism. 前輪駆動制御の制御手順を示すフローチャートである。It is a flowchart which shows the control procedure of front-wheel drive control. 従来例に係る前輪変速機構の作動回路を示す油圧回路図である。It is a hydraulic circuit diagram which shows the operation circuit of the front-wheel transmission mechanism which concerns on a prior art example.

符号の説明Explanation of symbols

1 ミッションケース
9 前輪変速機構
10 等速動力伝動経路
11 増速動力伝動経路
12 スプリング
13 スプリング作動型油圧クラッチ
14 スプリング
15 油圧作動型油圧クラッチ
17 第一の2位置切換弁
18 第二の2位置切換弁
19 制御装置
F 前輪
R 後輪
T トラクタ
DESCRIPTION OF SYMBOLS 1 Transmission case 9 Front-wheel transmission mechanism 10 Constant speed power transmission path 11 Increase speed power transmission path 12 Spring 13 Spring actuated hydraulic clutch 14 Spring 15 Hydraulic actuated hydraulic clutch 17 First two-position switching valve 18 Second two-position switching Valve 19 Control device F Front wheel R Rear wheel T Tractor

Claims (2)

前輪動力伝動経路に、後輪動力と略等速の動力を前輪に伝動する等速動力伝動経路と、後輪動力よりも増速された動力を前輪に伝動する増速動力伝動経路とを並列に構成すると共に、等速動力伝動経路には、スプリングの付勢力で入り状態となり、油圧供給により切り状態となるスプリング作動型油圧クラッチを介設する一方、増速動力伝動経路には、スプリングの付勢力で切り状態となり、油圧供給により入り状態となる油圧作動型油圧クラッチを介設し、これらの油圧クラッチの選択的な入り/切りにより、前輪を駆動させない2輪駆動状態と、前輪を後輪と略等速で駆動させる4輪駆動状態と、前輪を後輪よりも増速駆動させる前輪増速駆動状態とを現出させる作業用走行車において、前記等速動力伝動経路のスプリング作動型油圧クラッチを入り/切りさせる第一の2位置切換弁と、前記増速動力伝動経路の油圧作動型油圧クラッチを入り/切りさせる第二の2位置切換弁とを別個に備えるにあたり、前記第一、第二の2位置切換弁を、油圧ポンプから油圧作動型油圧クラッチに至る供給油路に直列に介在させて、該油圧作動型油圧クラッチの入り作動を第一、第二の2位置切換弁の入り側への単独切換では禁止するように構成したことを特徴とする作業用走行車。 In parallel to the front wheel power transmission path, a constant speed power transmission path for transmitting rear wheel power and substantially constant speed power to the front wheels and a speed increasing power transmission path for transmitting power increased from the rear wheel power to the front wheels in parallel. The constant-speed power transmission path is provided with a spring-actuated hydraulic clutch that is turned on by the urging force of the spring and turned off when the hydraulic pressure is supplied. A hydraulically actuated hydraulic clutch that is turned off by the urging force and turned on when the hydraulic pressure is supplied is provided. A two-wheel drive state in which the front wheels are not driven by selective on / off of these hydraulic clutches, In a working vehicle for realizing a four-wheel drive state in which a wheel is driven at substantially constant speed and a front wheel acceleration drive state in which a front wheel is driven at a speed higher than that of a rear wheel, a spring-operated type of the constant-speed power transmission path Hydraulic A first 2-position switching valve for On / Off the pitch, per the separately and a second 2-position switching valve for On / Off the hydraulic hydraulic clutches of the speed increasing power transmission path, the first The second two-position switching valve is interposed in series in the supply oil path from the hydraulic pump to the hydraulically operated hydraulic clutch, and the first and second two-position switching valves are operated to engage the hydraulically operated hydraulic clutch. A traveling vehicle for work characterized in that it is forbidden to switch to the entrance side of the vehicle alone . 4輪駆動状態から前輪増速駆動状態に切換えるとき、前記等速動力伝動経路のスプリング作動型油圧クラッチを切りにするタイミングに対し、前記増速動力伝動経路の油圧作動型油圧クラッチを入りにするタイミングを遅延させることを特徴とする請求項1記載の作業用走行車。   When switching from the four-wheel drive state to the front wheel acceleration drive state, the hydraulically operated hydraulic clutch of the speed increasing power transmission path is engaged with respect to the timing of disengaging the spring operated hydraulic clutch of the constant speed power transmission path. The working vehicle according to claim 1, wherein the timing is delayed.
JP2007045172A 2007-02-26 2007-02-26 Working vehicle Expired - Fee Related JP4847366B2 (en)

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JP3945669B2 (en) * 1997-12-19 2007-07-18 株式会社 神崎高級工機製作所 Front wheel transmission for a four-wheel drive vehicle
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JP4848602B2 (en) * 2001-07-31 2011-12-28 井関農機株式会社 Powered vehicle
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