JP7778669B2 - Tractor - Google Patents

Description

This invention relates to an agricultural tractor, and more specifically to a tractor equipped with an after-treatment device that removes particulate matter, nitrogen oxides, and other pollutants from the engine's exhaust gas.

Conventionally, a technology has been known in which aftertreatment devices (which may also be called exhaust gas purification devices) are provided in the exhaust path of a diesel engine, with a case containing a diesel particulate filter (hereinafter referred to as a DPF case) and a case containing a selective catalytic reduction catalyst (hereinafter referred to as an SCR case), and exhaust gas emitted from the diesel engine is introduced into both cases for purification treatment (see, for example, Patent Documents 1 and 2).

When using selective catalytic reduction (SCR) to remove nitrogen oxides from exhaust gas, a reducing agent (e.g., urea water) must be supplied. Therefore, when installing an SCR denitration device on a tractor, space is naturally required not only for the SCR case but also for the reducing agent tank.

Japanese Patent Application Laid-Open No. 2016-203753 JP 2016-74267 A

In prior art tractors, a pair of left and right fuel tanks are located on either side of the running body midway between the front and rear, with the reducing agent tank located in front of the left fuel tank. In other words, the left fuel tank and reducing agent tank are lined up front and rear. For this reason, even if it was desired to increase the capacity of the left fuel tank, there would naturally be a limit due to the length of the tractor from front to rear, and depending on its shape, it may be necessary to sacrifice the size of the control section (cabin) or steps, etc.

The technical objective of the present invention is to provide a compact tractor that takes into account and improves on the current situation described above.

A tractor according to one embodiment comprises a running body equipped with an engine, front and rear wheels supporting the running body, a step for accessing a control section on the running body, a fuel tank that supplies fuel to the engine, an aftertreatment device that purifies exhaust gas from the engine, and a reducing agent tank that stores reducing agent to be supplied to the aftertreatment device. At least a portion of the reducing agent tank and a first portion of the fuel tank are disposed on either the left or right side of the running body, between the front wheel and the step. The fuel tank has a second portion that extends rearward from the first portion, passing inside the reducing agent tank in the vehicle width direction.

FIG. 2 is a left side view of the tractor. FIG. FIG. FIG. FIG. 2 is a plan view of the traveling body of the tractor. FIG. 2 is a front view showing the internal structure of the tractor. FIG. 2 is a perspective view showing a urea water piping system. FIG. 4 is a rear view showing the support structure of the cabin. FIG. 2 is a front view showing the arrangement of the left tank and the urea water tank. FIG. 2 is a left side view showing the arrangement of the left tank. FIG. 2 is a plan view showing the layout of the urea water tank. FIG. 2 is a perspective view of the mounting structure for the urea water tank as viewed from the left rear. FIG. 2 is a perspective view showing the front shape of the urea water tank as viewed diagonally from the front left. FIG. 2 is a left side view of the left tank and the urea water tank. FIG. 2 is a right side view of the left tank and the urea water tank. FIG. 2 is a plan view of the left tank and the urea water tank. FIG. 2 is a front view of the left tank and the urea water tank. FIG. 2 is a rear view of the left tank and the urea water tank. FIG. 2 is a bottom view of the left tank and the urea water tank. FIG. 2 is a perspective view of the left tank and the urea water tank as viewed from diagonally front left. FIG. 2 is a perspective view of the left tank and the urea water tank as viewed from the rear right.

Embodiments embodying the present invention will be described below with reference to the drawings. First, the structure of the tractor 1 in this embodiment will be described with reference to Figures 1 to 6. The running body 2 of the tractor 1 in this embodiment is supported by a pair of left and right front wheels 3 and a pair of left and right rear wheels 4 as a running part. A common-rail diesel engine 5 (hereinafter simply referred to as the engine) mounted at the front of the running body 2 as a power source drives the rear wheels 4 and front wheels 3, allowing the tractor 1 to travel forward and backward. The engine 5 is covered by a hood 6. A cabin 7 (also known as a control part) is installed on the top surface of the running body 2. Inside the cabin 7, a driver's seat 8 and a control handle 9 are located, which are used to steer the front wheels 3 left and right by steering. Steps 10 for the operator to get on and off are provided on the left and right lower left sides of the cabin 7. A fuel tank 11 that supplies fuel to the engine 5 is installed below the bottom of the cabin 7.

The traveling vehicle body 2 comprises a front bumper 12, an engine frame 14 having a front axle case 13, and left and right vehicle frames 15 detachably fixed to the rear of the engine frame 14. Front axles 16 rotatably protrude outward from both left and right ends of the front axle case 13. Front wheels 3 are attached to both left and right ends of the front axle case 13 via the front axles 16. A transmission case 17 is connected to the rear of the vehicle frame 15 to transmit rotational power from the engine 5 to the four front and rear wheels 3, 3, 4, 4 with appropriate speed changes. The left and right front wheels 3 are covered above by left and right front fenders 26. The left and right front fenders 26 are supported on the left and right ends of the top surface of the front axle case 13.

A tank frame 18, which is a rectangular frame plate in bottom view and protrudes outward to the left and right, is bolted to the underside of the left and right vehicle frames 15 and the transmission case 17. In this embodiment, the fuel tank 11 is divided into two parts, left and right. The left and right fuel tanks 11 are mounted on the upper surfaces of the left and right protruding portions of the tank frame 18. In other words, the pair of left and right fuel tanks 11 are allocated to the left and right midway between the front and rear of the traveling vehicle body 2. The tank frame 18 extends to the right, and a battery 50 is located on the extended portion on the right side of the tank frame 18. In addition, one of the steps 10 is fixed to the extended portion on the right side of the tank frame 18. Left and right rear axle cases 19 are attached to the left and right outer surfaces of the transmission case 17 so as to protrude outward to the left and right. Left and right rear axles 20 are rotatably inserted into the left and right rear axle cases 19. Rear wheels 4 are attached to the transmission case 17 via the rear axles 20. The left and right rear wheels 4 are covered above by left and right rear fenders 21.

A hydraulic lifting mechanism 22 that raises and lowers a work machine (not shown), such as a rotary tiller, is detachably attached to the upper rear surface of the transmission case 17. The work machine is connected to the rear of the transmission case 17 via a three-point link mechanism consisting of a pair of left and right lower links 23 and a top link 24. A PTO shaft 25 that transmits PTO driving force to the work machine protrudes rearward from the rear side of the transmission case 17.

As shown in Figures 5 to 8, the exhaust path of the engine 5 is equipped with aftertreatment devices, including a first case 31 (which may be referred to as a DPF case) and a second case 32 (which may be referred to as an SCR case). The aftertreatment devices remove particulate matter (such as soot) and nitrogen oxides (NOx) from the exhaust gas of the engine 5 and discharge the purified exhaust gas to the outside. In this embodiment, the first case 31 houses an oxidation catalyst and a soot filter (not shown). The second case 32 houses an SCR catalyst for urea selective catalytic reduction and an oxidation catalyst (not shown). The first case 31 is mounted on top of the engine 5 in a position along the crankshaft direction (front-to-rear direction in this embodiment). The second case 32 is positioned vertically so that exhaust gas flows from bottom to top, on the lower right side of the front of the cabin 7.

The exhaust inlet side of the purification outlet pipe 33, which is longitudinal from front to rear, is connected to the exhaust outlet side of the first case 31. A bellows tube section 34 for vibration absorption is provided midway along the length of the purification outlet pipe 33. The exhaust inlet side (upper end side) of the urea mixing pipe 35 is connected to the exhaust outlet side of the purification outlet pipe 33. The urea mixing pipe 35 is approximately L-shaped, extending from below to above on the front right side of the cabin 7 and bending away from the engine 5 below the cabin 7. The exhaust outlet side (lower end side) of the urea mixing pipe 35 is connected to the underside of the left side of the second case 32. The connection between the exhaust outlet side of the purification outlet pipe 33 and the exhaust inlet side of the urea mixing pipe 35 is connected to the engine 5 via a flange. The exhaust outlet side of the purification outlet pipe 33 and the exhaust inlet side of the urea mixing pipe 35 are supported by the engine 5. The underside of the second case 32 is connected to the right front support base 96 (described later) via a case support bar 48. Exhaust gas that passes through the first case 31 is introduced into the second case 32 via the purification outlet pipe 33 and the urea mixing pipe 35.

A urea water spray unit 36 is attached to the upper end of the urea mixing pipe 35. Urea water (reducing agent) from a urea water tank 51 (reducing agent tank) (described below) is supplied from the urea water spray unit 36 into the urea mixing pipe 35, and the urea water is hydrolyzed and mixed as ammonia in the exhaust gas flowing from the first case 31 to the second case 32. Note that other reducing agents, such as anhydrous ammonia or ammonia water, can be used instead of urea water.

An assist bar 38 is provided on the front right side of the box-shaped cabin frame 37 that makes up the cabin 7. A vertically long tail pipe 39, which discharges exhaust gases to the outside, is connected to the assist bar 38 at multiple points. The tail pipe 39 is supported by the assist bar 38. The exhaust inlet side of the tail pipe 39 is connected to the exhaust outlet side (top side) of the second case 32. Exhaust gases from the engine 5 are purified by the first case 31 and the second case 32, and are then discharged outside the aircraft through the tail pipe 39.

In the above configuration, the oxidation catalyst and soot filter in the first case 31 first reduce particulate matter (PM), carbon monoxide (CO), and hydrocarbons (HC) in the exhaust gas from the engine 5. Next, inside the urea mixing tube 35, the exhaust gas passing through the first case 31 is mixed with urea water from the urea water injection unit 36, and the SCR catalyst and oxidation catalyst in the second case 32 reduce nitrogen oxides (NOx) in the exhaust gas mixed with the urea water as ammonia. The exhaust gas that has passed through the second case 32 is then discharged outside the aircraft through the tailpipe 39.

As shown in Figures 4 and 5, the fuel tank 11 includes a left tank 11L and a right tank 11R located under the cabin 7, inboard of the pair of left and right steps 10 and the rear wheels 4 (towards the vehicle frame 15). The left tank 11L and the right tank 11R are arranged on either side of the pair of vehicle frames 15. That is, the front portion of the left tank 11L is located between the left vehicle frame 15 and the left step 10, while the rear portion is located between the left vehicle frame 15 and the left rear wheel 4. Similarly, the front portion of the right tank 11R is located between the right vehicle frame 15 and the right step 10, while the rear portion is located between the right vehicle frame 15 and the right rear wheel 4. The left tank 11L and the right tank 11R have different capacities. The left and right tanks 11L and 11R are connected to each other via fuel communication pipes (not shown) at the lower left and right inward-facing side surfaces of the tanks 11L and 11R. The large-capacity left tank 11L protrudes forward of the left step 10 in front of the cabin 7. In other words, the left tank 11L is shaped to surround the right and front sides of the left step 10.

The fuel tank 11 is placed on a tank frame 18 that protrudes outward to the left and right from the underside of the aircraft frame 15 and is secured in place with bands 40. The tank frame 18 is formed into a rectangular frame plate in bottom view, and is made up of a front cross-rail frame 41 suspended from the left and right aircraft frames 15, a rear cross-rail frame 42 secured to the underside of the transmission case 17, and left and right tank mounting plates 43 secured to both ends of each cross-rail frame 41, 42. The left and right tank mounting plates 43 each have approximately the same shape as the bottom of the left tank 11L and right tank 11R, respectively, and are secured with bands 40 at two locations, front and rear, of each of the left and right tanks 11L and 11R placed on their top surfaces.

As such, the tank frame 18 is composed of a pair of front and rear horizontal rail frames 41, 42 extending left and right from the underside of the left and right aircraft frames 15, and a pair of left and right tank mounting plates 43 mounted front and rear on both the left and right sides of the front and rear horizontal rail frames 41, 42. The corresponding left and right fuel tanks 11L, 11R are mounted and fixed on the left and right tank mounting plates 43.

As shown in Figures 1 to 5, steps 10 for the operator to board and disembark are provided on the left and right lower sides of the cabin 7. As shown in Figure 8, the left step 10 is erected on the left end of the front cross-rail frame 41. A left front support base 96 is attached to the upper end of the left step 10. In this embodiment, the left step 10 is composed of two tiers of step members 44, 45, one above the other, and front and rear side plate members 46 connected to these step members 44, 45. The lower tier of step member 45 is fastened to the left end of the front cross-rail frame 41. The left front support base 96 is fastened to the upper ends of the front and rear side plate members 46. The front portion of the left tank 11L fits into the space surrounded by the left front support base 96, the left step 10, and the front cross-rail frame 41. Meanwhile, the lower tier of step member 45 constituting the right step 10 is fastened to the right end of the front cross-rail frame 41. The right step 10 consists of the lower step member 45 mentioned above and an upper step member 44 connected to the lower right part of the cabin frame 37.

A vertical support 47 is erected on the right side of the front cross-rail frame 41. A right front support base 96 is attached to the upper end of the vertical support 47. The front side of the right tank 11R fits into the space enclosed by the right front support base 96, the vertical support 47, and the front cross-rail frame 41. The front bottom of the cabin 7 is supported to the upper surfaces of the left and right front support bases 96 via vibration-isolating rubber bodies 98. A horizontally elongated case support bar 48 is fastened to the front side of the right front support base 96. The underside of the second case 32 is fastened to the upper right outer surface of the case support bar 48. Therefore, the second case 32 is supported by the right front support base 96 via the case support bar 48. A rear support base 97 is fastened to the middle of the left and right width of the top surfaces of the left and right rear axle cases 19, which extend horizontally in the left-right direction. The rear bottom of the cabin 7 is supported in a vibration-isolating manner on the upper surfaces of the left and right rear support bases 97 via vibration-isolating rubber bodies 99. Therefore, the traveling vehicle body 2 supports the cabin 7 in a vibration-isolating manner via multiple vibration-isolating rubber bodies 98, 99.

A battery base 49 is attached to the vertical support 47 midway between the top and bottom. A battery 50 is mounted on the battery base 49. In this embodiment, the battery 50 is located below the second case 32, and the lower tread member 45 of the right step 10 is located to the outside and right of the battery 50.

As shown in Figures 9 to 11, a tank recess 52 for accommodating a urea water tank 51 (reducing agent tank) is formed in the lower front portion of the left tank 11L. The urea water tank 51 is box-shaped and stores urea water (aqueous urea solution for selective catalytic reduction). When the urea water tank 51 is housed in the tank recess 52, the upper front portion 11LF of the left tank 11L and the urea water tank 51 are positioned vertically side by side. This makes it possible to secure both space for the urea water tank 51 and the capacity of the left tank 11L, and therefore the overall capacity of the fuel tank 11, without increasing the length of the tractor 1 or sacrificing the size of the cabin 7 (control section) or step 10.

An auxiliary frame 53 with a tank recess 52 is provided on the running vehicle body 2, extending toward the left tank 11L. In this case, one end of the auxiliary frame 53 is fastened to the left engine frame 14. A flat tank base 54 is fixed to the other end of the auxiliary frame 53. The tank base 54 is fastened to the left end of the front cross-rail frame 41 that constitutes the tank frame 18.

Insert nuts (not shown) are embedded in the bottom and rear of the urea water tank 51. With the urea water tank 51 housed in the tank recess 52, the bottom of the urea water tank 51 is fastened to the tank base 54 with bolts and insert nuts, and the rear of the urea water tank 51 is fastened to the front plate member 46 of the left step 10 with bolts and insert nuts (see Figures 4 and 12). The urea water tank 51 is stably fixed and supported by the left step 10 and the auxiliary frame 53.

A fuel filler cylinder 55 protrudes upward from the upper surface of the upper front portion 11LF of the left tank 11L. A supply cylinder 56 protrudes diagonally upward and outward from the left outer surface of the urea water tank 51. In this way, the fuel filler cylinder 55 and supply cylinder 56 protrude in different directions, so that fuel and urea water can be replenished from the same side (left side) of the traveling body 2, while making it difficult to mix up the fuel and urea water. In particular, in this embodiment, the fuel filler cylinder 55 for the fuel that is replenished more frequently is positioned above the urea water supply cylinder 56, significantly reducing the risk of accidentally supplying fuel to the urea water tank 51's supply cylinder 56.

As shown in FIG. 13 , a recess 57 is formed in the front of the urea water tank 51 to prevent interference with the left front wheel 3 (including the left front fender 26). In this embodiment, the recess 57 is recessed forward to follow the outer circumferential shape of the left front wheel 3 (including the left front fender 26). The presence of the recess 57 in the front of the urea water tank 51 eliminates the risk of the left front wheel 3 interfering with the urea water tank 51 when the front wheels 3, 3 are steered left or right. This makes it possible to position the urea water tank 51 as close as possible to the left front wheel 3, thereby enabling the tractor 1 to be made more compact in terms of its longitudinal length, etc.

As shown in Figures 7 and 8, the engine 5 (cooling water pump) and the urea water injection unit 36 are connected by a cooling water feed pipe 101 and a cooling water return pipe 102. One ends of the cooling water feed pipe 101 and the cooling water return pipe 102 are connected to the engine 5 (cooling water pump), and the other ends of the cooling water feed pipe 101 and the cooling water return pipe 102 are connected to the urea water injection unit 36. The cooling water heated by the engine 5 is sent from the cooling water feed pipe 101 to the cooling water return pipe 102 and passes through the urea water injection unit 36, preventing the urea water from freezing within the urea water injection unit 36. The cooling water that has passed through the urea water injection unit 36 is returned to the engine 5 (cooling water pump) via the cooling water return pipe 102.

A cooling water supply pipe 103 branches off from the middle of the cooling water feed pipe 101. The cooling water supply pipe 103 is connected to the tank sensor unit 58 attached to the urea water tank 51. In this case, an upwardly concave recess 51a is formed on the top surface of the urea water tank 51. The upward protrusion 51b on the top surface of the urea water tank 51 abuts against the bottom surface of the front upper part 11LF of the left tank 11L via an L-shaped buffer material 59. The tank sensor unit 58 described above is detachably attached to the top opening formed in the recess 51a of the urea water tank 51. The tank sensor unit 58 also functions as a lid for the top opening. The tank sensor unit 58 is connected to the cooling water supply pipe 103, cooling water recovery pipe 104, urea water feed pipe 105, urea water return pipe 106, etc.

The cooling water supply pipe 103 and the cooling water recovery pipe 104 are connected inside the urea water tank 51. The cooling water recovery pipe 104 is connected to the engine 5 (cooling water pump). Cooling water heated by the engine 5 is sent from the cooling water supply pipe 103 to the cooling water recovery pipe 104 and passes through the urea water tank 51, preventing the urea water from freezing inside the urea water tank 51. The cooling water that has passed through the urea water tank 51 is returned to the engine 5 (cooling water pump) via the cooling water recovery pipe 104.

The other ends of the urea water feed pipe 105 and urea water return pipe 106, one end of which is connected to the tank sensor unit 58, are connected to a urea water supply device 107 (supply module, reducing agent supply device) that supplies urea water from the urea water tank 51 to the urea water spray unit 36 of the urea mixing pipe 35. The urea water supply device 107 is connected to the urea water spray unit 36 via a urea water spray pipe 108. The urea water supply device 107 draws up urea water from the urea water tank 51 through the urea water feed pipe 105 and supplies urea water to the urea water spray unit 36 through the urea water spray pipe 108, spraying urea water into the urea mixing pipe 35. Excess urea water is returned to the urea water tank 51 via the urea water return pipe 106.

As shown in Figures 9 to 11, a urea water supply device 107 is disposed between the traveling body 2 and the urea water tank 51. Although detailed illustrations are omitted, the urea water supply device 107 includes a urea water pump that pumps the urea water in the urea water tank 51, and a drive motor that drives the urea water pump. The urea water supply device 107 supplies the urea water in the urea water tank 51 to the urea water spray section 36 of the urea mixing tube 35, causing the urea water spray section 36 to spray the urea water into the urea mixing tube 35. In this case, the urea water supply device 107 is disposed between the left body frame 15 and the urea water tank 51 and on the tank base 54. The dead space between the traveling body 2 (left body frame 15) and the urea water tank 51 can be effectively utilized as space for arranging the urea water supply device 107. The urea water piping system can be connected over a short distance from the urea water tank 51 to the urea water injection section 36 of the urea mixing pipe 35 via the urea water supply device 107.

As shown in Figures 10 and 11, one end of a breather pipe 109 for releasing pressure from the urea water tank 51 is connected to the tank sensor section 58 of the urea water tank 51. The other end of the breather pipe 109 is bifurcated. One of the bifurcated pipe sections 109a extends upward and opens. The other bifurcated pipe section 109b extends downward and opens at the center of the running body 2 (inside the front and rear wheels 3, 4). Therefore, when urea water is supplied, outside air is introduced through the upward pipe section 109a of the breather pipe 109, maintaining a constant pressure in the urea water tank 51. For example, even if the urea water tank 51 shakes due to engine 5 vibration or unevenness in the field, causing the urea water to get into the breather pipe 109, the urea water will spill out of the downward pipe portion 109b of the breather pipe 109, preventing the upward pipe portion 109a from being blocked by urea deposition or the like. Outside air can be reliably introduced smoothly through the breather pipe 109.

It goes without saying that the relative positions of the tank recess 52, urea water tank 51, and second case 32 are not limited to those shown in the embodiment, and may be reversed left and right. In this case, the relative positions of the battery 50, left and right fuel tanks 11, step 10, etc. will also be reversed left and right.

The configuration of each part in this invention is not limited to the illustrated embodiment, and various modifications are possible without departing from the spirit of this invention.

<Notes on the invention>
The present invention relates to a tractor comprising a running body on which an engine is mounted, a pair of left and right front and rear wheels supporting the running body, steps for getting on and off a control section on the running body, a fuel tank for supplying fuel to the engine, an aftertreatment device for purifying exhaust gas from the engine, and a reducing agent tank for storing reducing agent to be supplied to the aftertreatment device, wherein the reducing agent tank is positioned on either the left or right side of the running body and in front of the steps, the front wheels are positioned in front of the reducing agent tank, and a recess is formed in the front surface of the reducing agent tank.

Furthermore, in the tractor of the reference example, the recessed portion is recessed in a forward-facing concave shape that follows the outer peripheral shape of the front wheel 3.

In the tractor of the above reference example, the front wheels may be provided with fenders, and the recessed portion may be formed in front of the reducing agent tank on the side where the fenders are provided.

In the tractor of the above reference example, a fuel tank filler tube may be provided in front of the step and above the recessed portion of the reducing agent tank.

In the tractor of the above reference example, a supply tube for the reducing agent tank may be provided diagonally upward and outward, rearward of the recess in the reducing agent tank and on the left and right outer side surfaces of the reducing agent tank.

The present invention is configured as described above, allowing for a more compact tractor.

In the tractor of the above reference example, there is no risk of the front wheels interfering with the reducing agent tank, so the reducing agent tank can be positioned as close as possible to the front wheels.

REFERENCE SIGNS LIST 1 Tractor 2 Traveling machine body 3 Front wheels 5 Diesel engine 7 Cabin 10 Step 11 Fuel tank 11L Left tank 11LF Front upper part of left tank 11R Right tank 18 Tank frame 26 Front fender 31 First case 32 Second case 35 Urea mixing pipe 36 Urea water spray unit 39 Tail pipe 51 Urea water tank 52 Tank recess 55 Fuel supply cylinder 56 Supply cylinder 57 Recessed portion 58 Tank sensor unit 107 Urea water supply device

Claims (6)

A running body equipped with an engine,
Front wheels and rear wheels supporting the traveling machine body;
A step for getting on and off the control unit on the traveling machine body;
a fuel tank for supplying fuel to the engine;
an aftertreatment device that purifies exhaust gas from the engine;
a reducing agent tank that stores a reducing agent to be supplied to the aftertreatment device,
The fuel tank is
A first portion disposed on either the left or right side of the traveling machine body and between the front wheel and the step;
a second portion extending rearward from the first portion and disposed inside the step in the aircraft width direction,
At least a portion of the reducing agent tank overlaps with the first portion in the vertical direction ,
The first portion protrudes outward in the fuselage width direction from the control unit in a plan view.
Tractor. At least a portion of the fuel tank is located higher than the top end of the step.
2. The tractor of claim 1. The front wheels are provided with fenders,
at least a portion of the reducing agent tank and the first portion of the fuel tank are disposed between the fender and the step;
3. A tractor according to claim 1 or 2. a tank recess for accommodating the reducing agent tank is formed in the first portion of the fuel tank;
A tractor according to any one of claims 1 to 3. At least a part of the second portion of the fuel tank is located inside the rear wheel in the vehicle width direction.
A tractor according to any one of claims 1 to 4. The fuel tank has a shape that surrounds the inside and front side of the step in the aircraft width direction.
A tractor according to any one of claims 1 to 5.