Patent ID: 12214657

DESCRIPTION OF EMBODIMENTS

In the following, an embodiment of the present invention will be described with reference to the drawings. First, a structure of a tractor1of the present embodiment is described, with reference toFIG.1toFIG.6. A traveling body2of the tractor1of the present embodiment is supported by a pair of left and right front wheels3and a pair of left and right rear wheels4, as a traveling unit. The tractor1is structured to travel forward and backward by driving the rear wheels4and the front wheels3by means of a common rail type diesel engine5(hereinafter, simply referred to as engine) which is mounted in a front portion of the traveling body2and serves as a power source. The engine5is covered by a hood6. A cabin7(also referred to as operation unit) is installed on an upper surface of the traveling body2. In an inner portion of the cabin7, there are arranged an operation seat8and a steering handle9configured to move a steering direction of the front wheels3right and left by steering. Steps10with which an operator gets on and off the vehicle are provided such that one of them and the other of them are disposed respectively in left and right lower portions of the cabin7. A fuel tanks11for supplying fuel to the engine5is arranged below a bottom portion of the cabin7.

The traveling body2includes: an engine frame14including a front bumper12and a front axle case13; and left and right vehicle body frames15detachably fixed to a rear portion of the engine frame14. A front axle16rotatably protrudes outward from both left and right ends of the front axle case13. The front wheels3are attached to both left and right ends of the front axle casing13via the front axle16. A transmission case17is coupled to the rear portions of the vehicle body frames15. The transmission case17suitably shifts the rotary power from the engine5, and transmits the force to the four front and rear wheels3,3,4, and4. The left and the right front wheels3have upper sides covered with left and right front fenders26. The left and right front fenders26are supported above left and right end portions of the upper surface of the front axle case13.

A tank frame18having a rectangular plate shape in bottom view and protruding outward toward the left and the right is fastened with bolts to an under surface side of the transmission case17and the left and the right vehicle body frames15. In this embodiment, the fuel tanks11include two left and right tanks. The left and the right fuel tanks11are respectively mounted on the upper surface sides of the left and the right protruding portions of the tank frame18. That is, a pair of left and right fuel tanks11are arranged respectively on the left and right sides of a longitudinally (i.e., with respect to the front-rear direction) midway portion of the traveling body2. The tank frame18extends rightward, and a battery50is arranged in an extending portion on the right side of the tank frame18. Further, to the extending portion on the right side of the tank frame18one of the steps10is fixed. Left and right rear axle cases19are attached to left and right outer side surfaces of the transmission case17so as to protrude outwardly toward left and right, respectively. Left and right rear axles20are rotatably inserted in the left and the right rear axle cases19. The rear wheels4are attached to the transmission case17via the rear axles20. The left and the right rear wheels4have upper sides covered with left and right rear fenders21.

A hydraulic elevation mechanism22that can lift and lower a work machine (not illustrated), such as a rotary tiller for example, is detachably attached to an upper surface of the rear portion of the transmission case17. The work machine is coupled to the rear portion of the transmission case17via a three-point link mechanism including a pair of left and right lower links23and a top link24. A power-take off (PTO) shaft25protrudes rearward from a rear side surface of the transmission case17and is used for transmitting a PTO drive force to the work machine.

As shown inFIG.5toFIG.8, in an exhaust path of the engine5, a first case31(also referred to as DPF case) and a second case32(also referred to as SCR case) are provided as a post-processing device. The post-processing device removes particulate matter (e.g., soot and the like) and nitrogen oxides (NOx) contained in the exhaust gas of the engine5, and discharges purified exhaust gas to the outside. In the present embodiment, the first case31accommodates therein an oxidation catalyst and a soot filter (not shown). In the second case32, an SCR catalyst for urea selective catalytic reduction and an oxidation catalyst (not shown) are accommodated. The first case31is mounted at an upper portion of the engine5, along a crank axis direction (in the front-rear direction, in the present invention). The second case32is arranged on the lower right portion of the front portion of the cabin7, in a standing posture such that the exhaust gas flows from the bottom to the top.

An exhaust gas outlet side of the first case31is connected to an exhaust gas inlet side of a purification outlet pipe33which is long in a front-rear direction. In a midway portion of the purification outlet pipe33relative to its length direction, a bellows portion34for vibration absorption is provided. An exhaust gas outlet side of the purification outlet pipe33is coupled to an exhaust gas inlet side (upper end side) of a urea mixing pipe35. The urea mixing pipe35has a substantially L-shape, which extends upward from a lower side on a right front side of the cabin7, and at a lower side of the cabin7bent toward a direction away from the engine5. An exhaust gas outlet side (lower end side) of the urea mixing pipe35is coupled to a lower side of a left side portion of the second case32. The exhaust gas outlet side of the purification outlet pipe33and the exhaust gas inlet side of the urea mixing pipe35are coupled to the engine5through a flange. The engine5supports the exhaust gas outlet side of the purification outlet pipe33and the exhaust gas inlet side of the urea mixing pipe35. An under surface side of the second case32is coupled to a later-described right front-portion support pedestal96through a case support bar48. The exhaust gas having passed through the first case31is introduced into the second case32through the purification outlet pipe33and the urea mixing pipe35.

To an upper end side of the urea mixing pipe35, a urea water injection unit36is attached. Urea water (reductant) in a later-described urea water tank51(reductant tank) is supplied from the urea water injection unit36into the urea mixing pipe35, and the urea water is hydrolyzed and mixed as ammonia, into the exhaust gas from the first case31to the second case32. It should be noted that other reductant, e.g., ammonia or ammonia water may be used instead of urea water.

On the right side of the front portion of a box-frame-like cabin frame37constituting the cabin7, an assist bar38is provided. The assist bar38is coupled to a plurality of positions of a tail pipe39which is long in an up-down direction, and which emits the exhaust gas to the outside. The tail pipe39is supported by the assist bar38. An exhaust gas outlet side (upper surface side) of the second case32is connected to and in communication with an exhaust gas inlet side of the tail pipe39. The exhaust gas of the engine5is purified by the first case31and the second case32and is emitted to the outside the machine through the tail pipe39.

In the above structure, particulate matters (PM), carbon monoxide (CO), and hydrocarbon (HC) in the exhaust gas of the engine5are first reduced by the oxidation catalyst and the soot filter in the first case31. In the inside of the urea mixing pipe35, the urea water from the urea injection unit36is mixed with the exhaust gas having passed through the first case31, and the nitrogen oxide (NOx) in the exhaust gas in which the urea water is mixed as ammonia is reduced by the SCR catalyst and oxidation catalyst in the second case32. Then, the exhaust gas having passed through the second casing32is discharged to the outside of the machine from the tail pipe39.

As shown inFIG.4andFIG.5, a fuel tank11includes a left tank11L and a right tank11R arranged below the cabin7, and inward from a pair of left and right steps10and the rear wheels4(on the side of the vehicle body frames15). The left tank11L and the right tank11R are arranged respectively on the left and right so as to sandwich the pair of vehicle body frames15. That is, a front portion of the left tank11L is arranged between the left vehicle body frame15and the left step10, while a rear portion of the left tank11L is arranged between the left vehicle body frame15and the left rear wheel4. Similarly, a front portion of the right tank11R is arranged between the right vehicle body frame15and the right step10, while a rear portion of the right tank11L is arranged between the right vehicle body frame15and the right rear wheel4. The respective capacities of the left tank11L and the right tank11R are different from each other. The left and right tanks11L,11R communicate with each other through a fuel communication tube (not shown) at lower portions of their surfaces facing inward. The left tank11L with a large capacity protrudes forward from the left step10at the front of the cabin7. In other words, the left tank11L is formed so as to surround the right side and the front side of the left step10.

The fuel tank11is placed on the tank frame18outwardly protruding toward left and right below the vehicle body frames15, and fixed by a band40. The tank frame18is formed in a rectangular plate shape in a bottom view, with: a front lateral bridge frame41suspended and fixed to the left and right vehicle body frames15; a rear lateral bridge frame42fixed to an under surface of the transmission case17; and left and right tank mounting plates43fixed on both ends of the lateral bridge frames41,42. The shapes of the left and right tank mounting plates43are substantially the same as the shapes of the bottom surface of the left tank11L and the right tank11R, respectively, and the left tank11L and the right tank11R placed on the upper surfaces of the tank mounting plates43are fixed by bands40at two positions that are the front and the rear.

As described, the tank frame18is constituted by the pair of front and rear lateral bridge frames41,42extending left and right below the left and right vehicle body frames15, and the pair of left and right tank mounting plates43bridged in the front-rear direction, on both left and right sides of the front and rear lateral bridge frames41,42. On the left and right tank mounting plates43, the right and left fuel tanks11L,11R are placed and fixed, respectively.

As shown inFIG.1toFIG.5, the steps10for the operator to get on and off the vehicle are provided at lower portions on the left and right sides of the cabin7. As shown inFIG.8, the left step10is arranged to stand on the left end side of the front lateral bridge frame41. To the upper end side of the left step10, a left front-portion support pedestal96is attached. The left step10of the present embodiment includes two steps of foot plate members44,45, which are an upper and a lower foot plate members; and front and rear side plate members46coupled to these foot plate members44,45. The lower foot plate member45is fastened to the left end side of the front lateral bridge frame41. To the upper end sides of the front and rear side plate members46, the left front-portion support pedestal96is fastened. A portion of the left tank11L close to its front portion is fitted in a space surrounded by the left front-portion support pedestal96, the left step10, and the front lateral bridge frame41. To the right end side of the front lateral bridge frame41, a lower foot plate member45constituting the right step10is fastened. The right step10includes the lower foot plate member45and an upper step plate member44coupled to a lower right portion of the cabin frame37.

To a portion close to the right of the front lateral bridge frame41, a standing support column47is provided. To the upper end side of the standing support column47, the right front-portion support pedestal96is attached. In a space surrounded by the right front-portion support pedestal96, the standing support column47, and the front lateral bridge frame41, a front portion of the right tank11R is fitted. On the upper surface sides of the left and right front-portion support pedestals96, a front bottom portion of the cabin7is supported, in a vibration controlled manner, through a vibration rubber member98. On the front surface side of the right front-portion support pedestal96, a case support bar48long in the left-right direction is fastened. To the upper surface on the right outer side of the case support bar48, the under-surface side of the second case32is fastened. The second case32is supported by the right front-portion support pedestal96through the case support bar48. Each of the left and right rear axle cases19extended horizontally in the left-right direction has, on its upper surface, a rear portion support pedestal97fastened to a middle portion of the upper surface relative to the left-right width. On the upper surface side of each of the left and right rear portion support pedestals97, a rear bottom portion of the cabin7is supported, in a vibration controlled manner, through an anti-vibration rubber member99. Therefore, the traveling body2supports the cabin7in a vibration controlled manner, through the anti-vibration rubber members98,99.

A battery seat49is attached to a midway portion of the standing support column47relative to the up-down direction. The battery50is mounted on the battery seat49. In the embodiment, the battery50is located below the second case32, and the lower foot plate member45of the right step10is located on the right outside of the battery50.

As shown inFIG.9toFIG.11, in a lower-front portion of the left tank11L, a tank-accommodation recess52for accommodating the urea water tank51(reductant tank) is formed. The urea water tank51is a box-like member for containing urea water (urea water solution for selective catalytic reduction). An upper front portion11LF of the left tank11L and the urea water tank51are aligned up and down, while the urea water tank51is accommodated in the tank-accommodation recess52. This can achieve both: a space for arranging the urea water tank51, and the capacity of the left tank11L or even the capacities of both of the entire fuel tank11, without lengthening the longitudinal length of the tractor1or sacrificing the size of the cabin7(operation unit) and the step10.

An auxiliary frame53extended toward the left tank11L having the tank-accommodation recess52is provided to the traveling body2. In this case, one end side of the auxiliary frame53is fastened to the left engine frame14. The other end side of the auxiliary frame53fixes a tank seat54having a flat plate shape. The tank seat54is fastened to the left end side of the front lateral bridge frame41constituting the tank frame18.

To the bottom surface and the rear surface of the urea water tank51, an insert nut (not shown) is embedded. The bottom surface of the urea water tank51and the tank seat54are fastened with a bolt and the insert nut and the rear surface of the urea water tank51and a front side plate member46of the left step10are fastened with a bolt and the insert nut, while the urea water tank51is accommodated in the tank-accommodation recess52(seeFIG.4andFIG.12). With the left step10and the auxiliary frame53, the urea water tank51is stably fixed and supported.

On the upper surface of the upper front portion11LF of the left tank11L, a fueling cylinder55protrudes upward. On the left outer side surface of the urea water tank51, a supply cylinder56protrudes obliquely upward and outward. As described, since the direction in which the fueling cylinder55protrudes and the direction in which a supply cylinder56are different from each other, the fuel and the urea water can be supplied from the same side (left side) of the traveling body2, and yet mistakes in supplying wrong one of the fuel and the urea water becomes less likely to occur. Particularly, in this embodiment, the fueling cylinder55for the fuel which is more frequently supplied is positioned above the supply cylinder56for the urea water. Therefore, the risk of mistakenly supplying fuel to the supply cylinder56of the urea water tank51is reduced.

As shown inFIG.13, the front surface of the urea water tank51has a recess57to avoid interference with the left front wheel3(including a left front fender26). The recess57of this embodiment is a recess facing forward which is concaved along the outer circumference shape of the left front wheel3(including the left front fender26). With the recess57on the front surface of the urea water tank51, the left front wheel3hardly interfere with the urea water tank51when the front wheels3,3are steered left and right. Thus, the urea water tank51can be arranged as close as possible to the left front wheel3, and the longitudinal length of the tractor1and the like can be made compact.

As shown inFIG.7andFIG.8, the engine5(cooling water pump) and the urea water injection unit36are in communication with each other through a cooling water feed pipe101and a cooling water return pipe102. One ends of the cooling water feed pipe101and the cooling water return pipe102are connected to the engine5(cooling water pump). The other ends of the cooling water feed pipe101and the cooling water return pipe102are connected to the urea water injection unit36. The cooling water feed pipe101and the cooling water return pipe102are connected in the urea water injection unit36. The cooling water heated by the engine5is fed from the cooling water feed pipe101to the cooling water return pipe102through the urea water injection unit36, thus keeping the urea water from being frozen in the urea water injection unit36. The cooling water having passed through the urea water injection unit36is returned to the engine5(cooling water pump) through the cooling water return pipe102.

A cooling water supply pipe103is branched from a middle portion of the cooling water feed pipe101. The cooling water supply pipe103is connected to a tank sensor unit58attached to the urea water tank51. In this case, an indentation51awhich is a recess opened upward is formed on the upper surface side of the urea water tank51. An upward protrusion51bon the upper surface side of the urea water tank51is in contact with the bottom surface of the upper front portion11LF in the left tank11L through an L-shaped buffer member59. The tank sensor unit58is detachably attached to an upper surface opening of the indentation51aof the urea water tank51. The tank sensor unit58also functions as a lid of the upper surface opening. The tank sensor unit58is connected to the cooling water supply pipe103, a cooling water collection pipe104, a urea water feed pipe105, a urea water return pipe106, and the like.

The cooling water supply pipe103and the cooling water collection pipe104are connected in the urea water tank51. The cooling water collection pipe104is connected to the engine5(cooling water pump). The cooling water heated by the engine5is fed from the cooling water supply pipe103to the cooling water collection pipe104through the urea water tank51, thus keeping the urea water from being frozen in the urea water tank51. The cooling water having passed through the urea water tank51is returned to the engine5(cooling water pump) through the cooling water collection pipe104.

The other ends of the urea water feed pipe105and the urea water return pipe106whose one ends are connected to the tank sensor unit58are connected to a urea water supply device107(supply module, reductant supply device) configured to supply urea water in the urea water tank51to the urea water injection unit36of the urea mixing pipe35. The urea water supply device107is connected to the urea water injection unit36through a urea water injection pipe108. The urea water supply device107sucks the urea water in the urea water tank51through the urea water feed pipe105, and supplies the urea water to the urea water injection unit36through the urea water injection pipe108, to spray the urea water in the urea mixing pipe35. The surplus urea water is returned to the urea water tank51through the urea water return pipe106.

As shown inFIG.9toFIG.11, the urea water supply device107is arranged between the traveling body2and the urea water tank51. Although details are omitted, the urea water supply device107includes a urea water pump configured to pressure-feed the urea water in the urea water tank51, and a drive motor configured to drive the urea water pump. By the urea water supply device107supplying the urea water in the urea water tank51to the urea water injection unit36of the urea mixing pipe35, the urea water is sprayed from the urea water injection unit36into the urea mixing pipe35. In this case, the urea water supply device107is arranged on the tank seat54between the left vehicle body frame15and the urea water tank51. Thus, a dead space between the traveling body2(left vehicle body frame15) and the urea water tank51is effectively used as a space for arranging the urea water supply device107. Therefore, the distance of the urea water piping system from the urea water tank51to the urea water injection unit36of the urea mixing pipe35through the urea water supply device107can be shortened.

As shown inFIG.10andFIG.11, the tank sensor unit58of the urea water tank51is connected to one end of a breather pipe109for relieving the pressure of the urea water tank51. The other end of the breather pipe109is branched into two branches. One of the branched pipe portions109ais extended upward and opened. The other one of the branched pipe portions109bis extended downward and opened at a midway of the traveling body2relative to the left-right direction (further inward than the front and rear wheels3and4, relative to the left-right direction). Therefore, the pressure in the urea water tank51is kept constant by introducing outside air through the upward pipe portion109aof the breather pipe109, at a time of supplying the urea water. For example, even if the vibration of the engine5or shaking of the urea water tank51caused by unevenness of the field causes the urea water to enter the breather pipe109, the urea water drops from the downward pipe portion109bof the breather pipe109. Therefore, clogging of the upward pipe portion109acaused by, for example, adhesion and deposition of the urea can be avoided. Therefore, smooth introduction of the outside air can be reliably performed through the breather pipe109.

It goes without saying that the positional relationship among the tank-accommodation recess52, the urea water tank51, and the second case32is not limited to the example mentioned in this embodiment, and the left and right sides may be reversed. In such a case, the positional relationship among the battery50, the left and right fuel tanks11, the steps10, and the like are also reversed.

The configurations of respective parts of the present invention are not limited to those of the illustrated embodiment, but can be variously changed without departing from the gist of the invention.

REFERENCE SIGNS LIST

1tractor2traveling body5diesel engine7cabin10step11fuel tank11L left tank11LF upper front portion of left tank11R right tank18tank frame31first case32second case35urea mixing pipe36urea water injection unit39tail pipe51urea water tank52tank-accommodation recess55fueling cylinder56supply cylinder57recess58tank sensor unit107urea water supply device