JP6733117B2 - Work vehicle - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work vehicle such as a tractor mainly for agriculture, and more particularly, to a work vehicle in which auxiliary components for an engine are provided on a radiator bracket provided in front of the engine.

In order to comply with exhaust gas regulations, diesel engines installed in work vehicles such as tractors store high-pressure fuel in a supply pump in rails (accumulation chambers), and ECUs control the injectors for each cylinder in good timing. A common rail system for injecting an appropriate amount of fuel is adopted for this, and by this high fuel injection pressure, the fuel is made into fine particles, the unburned residue of the fuel is reduced, and the generation of PM (particulate matter) is suppressed. In addition, a turbocharger forcibly sending dense air and an air-cooled intercooler are installed to increase engine output, improve fuel efficiency, and reduce CO2 (carbon dioxide) and PM emissions.

In addition, an EGR (Exhaust Gas Recirculation) valve, throttle valve, water-cooled EGR cooler that lowers the temperature of the exhaust gas that becomes high temperature, etc. are used to recirculate a part of the exhaust gas to the engine. Generation of NO _X (nitrogen oxide) is suppressed by lowering the combustion temperature. Then, a DOC (diesel oxidation catalyst) that oxidizes HC (hydrocarbon) and CO (carbon monoxide), which are harmful components in the exhaust gas, into water and CO2 to render them harmless is provided.

Now, considering a fuel supply system for a diesel engine that takes such measures against exhaust gas, this supply system supplies fuel from a fuel tank to a common rail system via a low-pressure pump (feed pump). Further, the surplus fuel of the supply pump and the surplus fuel of the common rail and the injector, which are not consumed in the common rail system, are merged and returned to the fuel tank. The fuel returning from the common rail and the injector to the fuel tank passes through the high temperature part of the engine and is therefore extremely hot.

When the high temperature surplus fuel is returned to the fuel tank, the temperature of the entire fuel stored in the fuel tank also gradually rises. Further, when the high temperature fuel stored in the fuel tank is supplied to the supply pump, the lubricity of the fuel used for lubrication is deteriorated, and the supply pump is apt to be worn or seized. Further, an increase in fuel temperature or a decrease in fuel viscosity may reduce the durability of the low-pressure pump (feed pump) itself that supplies fuel from the fuel tank to the supply pump.

Therefore, in order to prevent damage to the supply pump and the like, it is also provided with a safety protection function that automatically saves the output of the engine when the fuel temperature exceeds a certain temperature and lowers the fuel temperature. However, in this case, the output of the engine decreases and the engine speed becomes unstable, which may hinder the work performed at a constant engine speed.

Therefore, in order to solve these problems, the fuel supplied to the supply pump or the like is cooled by various cooling devices or the like. That is, as a cooling device in this case, one that passes cooling air of a radiator (air-cooling type fuel cooler) through a heat exchanger composed of an aluminum core integrated with radiating fins (for example, see Patent Documents 1 and 2), It is known to use a conduit made of a good material to cool the fuel.

Japanese Patent No. 5037297 JP, 2010-174854, A

As described above, in addition to the radiator that lowers the temperature of engine cooling water, the diesel engine includes an air-cooled intercooler and a fuel cooler that cools fuel supplied to a supply pump and the like in order to comply with exhaust gas regulations. In these heat exchangers, a radiator is first provided in front of a cooling fan driven by an engine, and further an intercooler or a fuel cooler is provided in front of the radiator in a row or in a row so that their heat radiating surfaces are overlapped with each other. Cooled together with the radiator by the suction air of the fan.

When heat exchangers such as an intercooler and a fuel cooler are added in addition to the radiator in this way, it is necessary to increase the amount of air required to cool them, and at the same time, perform heat exchange as the cooling load increases. It is also necessary to increase the size of vessels. However, in a work vehicle in which engine accessories including a heat exchanger such as a radiator are placed on a radiator bracket provided in front of the engine and the engine and accessories are covered with a bonnet, the space where these accessories are provided Cannot be widened due to various restrictions such as securing the steering angle of the front wheels provided on the left and right and securing the front view.

Therefore, it is required to rationally arrange the auxiliary devices in the limited space to improve the cooling efficiency of the heat exchanger. However, as in Patent Document 1, a radiator, a hydraulic oil cooler, a condenser, and a fuel oil cooler are sequentially provided from a rear side to a front side on a bottom plate installed on a body frame, and a battery is further provided in front of the radiator to cool the bonnet. When the air flow from the front of the vehicle taken in at the front end is passed in order over the battery to the fuel oil cooler, the condenser, the hydraulic oil cooler, and the radiator, it is obstructed by the blocked batteries and the upper side in the vertical direction of each heat exchanger. At any rate, it becomes difficult for the airflow to flow from the middle part to the lower side, and it may not be possible to efficiently cool the large-sized heat exchanger.

Further, as in Patent Document 2, a fuel cooler is arranged in a dead space formed by an air cleaner, a condenser, an oil cooler, and a radiator on the upper surface side of a mounting plate fixed to a body frame, or a fuel cooler. Is placed between the radiator and the oil cooler to prevent fuel from falling onto the battery or battery cable even if the fuel cooler is damaged, and the upper end of the fuel cooler is higher than the upper end of the oil cooler. If it is arranged so as to be located above, cold air can be applied to the fuel cooler without being blocked by the oil cooler.

However, if the fuel cooler is provided at the rear of the air cleaner, there is a possibility that the air cooler may interfere and the cold air may not be applied to the fuel cooler. If the fuel cooler is placed between the radiator and the oil cooler and the upper end of the fuel cooler is located above the upper end of the oil cooler, the fuel cooler will not be blocked by the oil cooler as described above. You can apply cold air. However, since the lower end of the fuel cooler overlaps the condenser and the oil cooler in the front-rear direction, the warmed air hits the condenser and the oil cooler, and the cooling efficiency may not be improved as expected. There is.

The temperature of the fuel supplied to the engine changes depending on the load condition of the engine, the ambient temperature, the amount of fuel remaining in the fuel tank, the atmosphere in which the engine is placed, etc. The high temperature surplus fuel returned to the fuel tank is supplied to the engine as it is, and the temperature of the fuel supplied to the engine rises. Also, when the condenser needs to be cooled by the operation of the air conditioner, the temperature of the exhaust air after cooling the heat exchangers such as the condenser and the radiator becomes high, and even if this exhaust air is applied to the engine by a cooling fan and air-cooled, The engine temperature does not drop much, and the fuel temperature rises accordingly.

And, as mentioned above, damage to the supply pump and the like caused by the rise in the fuel temperature, and the decrease in engine output due to the activation of the safety protection function to prevent this are one of the most important problems for work vehicles, Cooling of the fuel cooler must be ensured prior to cooling of other heat exchangers.

Therefore, in view of the above problems, the present invention rationally arranges engine accessories including a radiator provided in front of the engine in a limited space on a radiator bracket, and in particular, heat related to the engine is reduced. An object of the present invention is to provide a work vehicle capable of reliably and effectively cooling an exchanger, especially a fuel cooler.

In order to solve the above-mentioned problems, the present invention arranges engine accessories including a radiator for cooling an engine on a radiator bracket provided in front of the engine, and covers the engine and accessories with a bonnet. In, the battery is provided at the front part of the radiator bracket and the radiator is provided at the rear part, and an auxiliary device mounting stay is erected at an intermediate portion between the battery and the radiator, and the auxiliary device mounting stay is provided above the auxiliary device mounting stay. On the other hand, the air cleaner that composes the engine's auxiliary equipment is placed above, and below that, an air-cooled return-side fuel cooler that cools the excess fuel that returns from the engine to the fuel tank, and the fuel supplied to the engine from the fuel tank. By installing the air-cooling type suction side fuel cooler, the return side cooler and the suction side cooler are configured so that heat can be effectively exchanged at a high position avoiding the battery.

Further, the present invention, the suction side fuel cooler, characterized in that provided in front of the fuel cooler of the return side.

According to the work vehicle of the present invention, the radiator bracket is provided with the battery at the front part and the radiator is provided at the rear part, and the auxiliary device attaching stay is erected at the intermediate part between the battery and the radiator. The air cleaner that composes the engine auxiliary equipment is placed above the mounting stay, and the air-cooled heat exchanger is attached below it, so that the heat exchanger is effectively heated at a high position avoiding the battery. Since it is configured so that it can be replaced, the outside air taken in from the bonnet inlet can be applied to the air-cooled heat exchanger that forms the auxiliary equipment of the engine without being blocked by the battery installed in the front or the air cleaner installed above. , It can be cooled effectively.

In addition, the auxiliary device mounting stay that is erected in the middle between the battery and the radiator can also be used as the mounting stay for the air cleaner and the air-cooled heat exchanger, thus reducing the cost when manufacturing the radiator bracket. Can be planned. Moreover, even if the air-cooling type heat exchanger is enlarged in order to secure the required heat exchange capacity, the heat exchanger is attached to a single member called the auxiliary device mounting stay, so the work vehicle shakes while traveling. Also, it is difficult for the phase difference to occur in the upper and lower or left and right mounting parts of the heat exchanger, temporarily attach the upper and lower or left and right mounting parts of the heat exchanger to separate members, and give a load to the heat exchanger by the phase difference. It is possible to prevent the harmful effects of deforming or damaging the heat exchanger and scattering the medium of the heat exchanger around.

Furthermore, if the air-cooled heat exchanger is a fuel cooler that cools the fuel of the engine, a common rail system is adopted to comply with exhaust gas regulations, and as a result, excess hot fuel is returned to the fuel tank. Since the temperature of the fuel, which is totally hot, can be cooled by the fuel cooler to lower the temperature, it is possible to prevent damage to the supply pump, etc., and a reduction in engine output due to the activation of the safety protection function to prevent this. ..

Moreover, if the fuel cooler is a return side cooler that cools the excess fuel returning from the engine to the fuel tank, the excess fuel is cooled by the return side cooler and returns to the fuel tank, so that the fuel tank becomes hot. It is possible to prevent the deterioration of the fuel tank material such as the resin tank due to the fuel temperature.

In addition, if the fuel cooler is a return-side cooler that cools excess fuel that returns from the engine to the fuel tank and a suction-side cooler that cools fuel that is supplied from the fuel tank to the engine, heat exchange of the return-side fuel cooler is performed. The capacity cannot be secured due to restrictions on the installation space, etc., and the fuel that could not be cooled down due to this, or the fuel that became hot again during the process of supplying it from the fuel tank to the engine is cooled by the cooler on the suction side. Therefore, the fuel temperature can be surely lowered to an allowable value.

Further, when the suction side fuel cooler is provided in front of the return side fuel cooler, the suction side fuel cooler can be provided by utilizing an empty space in front of the return side fuel cooler. Moreover, the fuel cooled on the return side and the fuel totally cooled by the fuel stored in the fuel tank, the fuel cooler on the suction side only needs to slightly lower the temperature to an allowable temperature, and therefore the size can be reduced. A fuel cooler on the suction side capable of performing the above is provided in front of the fuel cooler on the return side, and the taken-in outside air can be applied to the fuel cooler on the return side without being blocked, and this can be cooled effectively.

As a result, the fuel cooler on the return side is cooled by the air warmed by the fuel cooler on the front suction side, but the heat dissipation amount of the fuel cooler on the suction side is small and the fuel cooler on the suction side is The outside air taken in directly hits the front surface of the fuel cooler on the return side, which does not overlap, and can cool it, so that the influence can be almost ignored.

It is a side view of the tractor of 1st Embodiment. It is explanatory drawing of the fuel supply system of an engine. It is a perspective view of a radiator bracket. It is a perspective view showing the state where an auxiliary machine was attached to a radiator bracket. It is a side view which shows the state which attached the auxiliary device to the radiator bracket. It is a perspective view which shows the state which attached the fuel cooler of the return side to the auxiliary equipment attachment stay. It is a front view which shows the state which attached the return side fuel cooler to the auxiliary equipment attachment stay. It is a perspective view of a mounting bracket of a fuel cooler. It is a side view of the tractor of 2nd Embodiment. It is explanatory drawing of the fuel supply system which added the fuel cooler of the suction side. It is a perspective view which shows the attachment state of the fuel cooler on the suction side. It is a side view of 2nd Embodiment which attached the auxiliary device to the radiator bracket. It is a perspective view which shows the attachment state of an oil cooler.

A first embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 1, a tractor 1 as a work vehicle constitutes a vehicle body (machine body) by integrally connecting an engine 2, a clutch housing 3, a transmission case 4 and the like from the front. Further, on the front side of the vehicle body, a bonnet 5 that covers the engine 2 and auxiliary devices of the engine 2 and left and right side covers 6 are provided. The side cover 6 is detachably provided on the vehicle body.

Further, the front axle case is pivotally supported on the front bracket 7 which is fixed to the engine 2 and extends forward so as to be swingable left and right. Attach the front axle case (king pin case and final case) to the left and right ends of this front axle case. The front axle case pivotally supports the front axle 9 to which the front wheel 8 is attached, and the steering wheel 10 provided in the steering section steers the left and right front wheels 8. On the other hand, a rear axle case connected to the left and right of the transmission case 4 is provided on the rear side of the vehicle body, and left and right rear wheels 12 are attached to a rear axle 11 pivotally supported by the rear axle case.

A well-known three-point link mechanism including a top link 13 and left and right lower links 14 is provided on the rear portion of the vehicle body. This three-point link mechanism connects working machines such as mowers and rotary tillers, and the working machines are the left and right lift arms of the hydraulic housing attached to the upper part of the mission case 4, and the ends of the left and right lift arms and the left and right lift arms. The lower link 14 is lifted up and down via a lift rod having one end connected to the lower link. Further, engine power is transmitted to the work machine from a PTO shaft (power take-off shaft) that is pivotally supported at the rear of the mission case 4.

Further, the floor 15 is attached to the vehicle body behind the engine 2 via a vibration isolator. A steering wheel 10 is provided on a steering column near the front of the floor 15, and a meter panel 16 including an instrument panel and a rear panel cover 17 that covers the lower side thereof are provided. Further, a driver's seat 18 is provided on the lower seat cover near the rear of the floor 15, and left and right fenders 19 are provided on the sides of the driver's seat 18. Then, right and left lower support columns 20 are provided at the rear of the driver's seat 18, and an inverted U-shaped roll bar 21 is attached to the upper part of the lower support columns 20 to form a safety frame.

In addition, 22 is a sub-step which is a stepping board for getting on and off when it hangs down from the floor 15, 23 is a left and right fuel tanks mounted below the floor 15 via tank brackets 24, and the left and right fuel tanks communicate with each other. As shown in FIG. 9, a suction hose that sends fuel to a segmenter 25 (see FIG. 9) that removes water from the fuel is connected to the fuel tank 23 on the right side, and the excess fuel of the engine 2 is returned to the fuel tank 23. Connect the hose. Further, a fuel filler port 23a is provided in the upper part on the front side of the left fuel tank 23, and 26 is a cap for covering this.

Further, various operating tools are provided in the control section around the driver's seat 18. First, the forward/reverse switching lever 27 is provided on the left side cover that covers the upper portion of the steering column, and the engine control lever 28 is provided on the right side. A clutch pedal 29 is provided on the left side near the front of the floor 15, and left and right brake pedals (not shown) are provided on the other side. Further, between the driver's seat 18 and the fender 19 on the right side, a position control lever for raising and lowering the work machine, and a PTO shift lever, and between the driver's seat 18 and the fender 19 on the left side, a main shift lever for changing the vehicle speed, Provide a sub gear shift lever.

Next, the above-mentioned engine 2 will be described. The engine 2 uses a diesel engine that uses light oil as fuel. Further, in order to comply with the exhaust gas regulation, the fuel whose pressure has been increased by the supply pump 30 is stored in the common rail 31 (accumulation chamber), and the fuel is injected from the injector 33 to each cylinder under the control of the ECU 32 (electronic control unit). Adopt a common rail system. Furthermore, a turbocharger forcibly sending high-density air using the flow of exhaust gas and an intercooler 34 for cooling the air pressurized by the turbocharger are provided.

In addition, an EGR (Exhaust Gas Recirculation) valve, a throttle valve, an EGR system that recirculates a part of the exhaust gas to the engine by a water-cooled EGR cooler that lowers the temperature of the exhaust gas that becomes hot, etc. is adopted. A DOC (diesel oxidation catalyst) is provided as a processing device.

Further, the fuel system for supplying fuel to the engine 2 will be described. As shown in FIG. 2, the fuel stored in the left and right fuel tanks 23 enters the segmenter 25 via the suction hose and water in the fuel is removed. To reach the pre-filter 35. Here, the prefilter 35 collects impurities in the fuel. An electromagnetic pump (feed pump) 36 is provided on the downstream side of the pre-filter 35, and the feed pump 36 sends the fuel sucked from the fuel tank 23 to the main filter 37.

Further, the main filter 37, like the pre-filter 35, collects finer impurities in the fuel. Further, the fuel supplied to the supply pump 30 becomes a high pressure and is sent to the common rail 31, and further, the fuel is injected from the common rail 31 to each cylinder via the injector 33. The surplus fuel of the supply pump 30 that has not been consumed in the common rail system and the surplus fuel of the common rail 31 and the injector 33 are merged and returned to the fuel tank 23 through the return hose.

However, when the engine 2 is operated and, for example, in an environment in which the outside air temperature is 35 degrees Celsius, the surplus fuel of the supply pump 30 is about 60 degrees Celsius or less, while the common rail 31 passing through the high temperature portion of the engine 2 and The surplus fuel of the injector 33 is about 140 degrees Celsius, which is extremely high temperature. Therefore, before these excess fuels are returned to the fuel tank 23, they are cooled to about 60 degrees Celsius or less using the fuel cooler 38 and then returned to the fuel tank 23.

Then, the returned surplus fuel is mixed with the fuel in the fuel tank 23, whereby the fuel temperature in the fuel tank 23 becomes about 50 degrees Celsius or less, and this fuel is supplied to the feed pump 36 and the supply pump 30. .. Therefore, damage to the feed pump 36, the supply pump 30, etc. due to the high temperature fuel supply, which is caused by directly returning the surplus fuel to the fuel tank 23, is prevented. Further, the activation of the safety protection function of the ECU 32 for the purpose of preventing the pump damage due to the increase in the fuel temperature is suppressed, and the output of the engine 2 can be prevented from decreasing.

Next, the arrangement of the auxiliary devices of the engine 2 will be described mainly by the mounting and cooling method of the fuel cooler 38. First, the front side of the bonnet 5 that covers the auxiliary devices of the engine 2 will be described. As shown in FIG. 1, a front grill portion 5a is provided, and a headlamp unit 39 is sandwiched in the front grill portion 5a, and ventilation holes 5b, 5c for taking in outside air are provided above and below the bonnet 5 above and below the head grill unit 39. Ventilation openings 5d and 5e are also provided on the side surface of the front grill portion 5a near the lower rear side to increase the amount of air taken in for cooling the auxiliary components of the engine 2. A net is provided at each of the ventilation ports 5b, 5c, 5d, and 5e to prevent dust from entering.

Then, the accessories of the engine 2 covered by the hood 5 are attached to a radiator bracket 40 which is fixed to the engine 2 and is attached on a front bracket 7 extending forward. That is, as shown in FIG. 3, the radiator bracket 40 is configured by fixing a radiator mounting stay 40b, an auxiliary device mounting stay 40c, a fuel filter mounting stay 40d, and a battery mounting stay 40e to a base 40a which is a bottom plate.

More specifically, the radiator mounting stay 40b has a gate-shaped frame frame standing upright at the rear end of the base 40a in the left-right direction, and the upper bracket 41 and the left and right plates 42 are mounted on the upper and left sides of the frame. The outer peripheral edges of the upper bracket 41 and the plate 42 close to the inner surface of the bonnet 5 in the closed state of the bonnet 5 to close the gap between the radiator mounting stay 40b and the bonnet 5, so that the radiator bracket 40 from the engine 2 side. It functions as a partition plate that prevents the hot air from blowing back to the side.

Further, the upper bracket 41 supports the upper portion of the radiator, and the left and right plates 42 are appropriately provided with holes for passing the piping of the auxiliary device. Further, fan shrouds 43 and 44 are attached to the rear side of the radiator attaching stay 40b, and a radiator net 45 is attached to the front side so that the radiator net 45 can be inserted and removed from the right side. The radiator mounting stay 40b thus configured mounts and supports the radiator 46, which mainly cools the cooling water of the engine 2, near the rear portion thereof.

A cooling fan 47 (see FIG. 12) provided in front of the engine 2 faces the fan shrouds 43, 44 attached to the rear portion of the radiator attachment stay 40b and is driven by the engine 2 via a belt. Therefore, the cooling fan 47 sucks the air on the front side of the front surface of the radiator 46 through the radiator 46 main body, whereby the cooling water of the engine 2 flowing through the radiator 46 is cooled by the suction wind. .. The exhaust air discharged from the cooling fan 47 flows from the front surface of the engine 2 to the outer peripheral surface of the main body to air-cool the engine 2.

Further, the accessory mounting stay 40c is a pipe frame having a leg a that rises upward from the right end of the base 40a in front of the radiator mounting stay 40b and an upper portion b that is substantially parallel to the base 40a and is bent rearward from the left and right directions. Formed by. The rear end of the upper part b is fixed to the radiator mounting stay 40b, and the auxiliary device mounting stay 40c and the radiator mounting stay 40b are mutually reinforced. In addition, a mounting portion S of the air cleaner 48 that purifies the air supplied to the engine 2 is provided on the upper portion b of the accessory mounting stay 40c by combining a plurality of plates c.

Further, the fuel filter mounting stay 40d includes a leg portion d that rises upward from the left end of the base 40a on the opposite side of the leg portion a of the accessory mounting stay 40c, and a mounting portion e provided above the leg portion d. A connecting portion f that further rises toward the front end of the auxiliary device mounting stay 40c. The upper end of the connecting portion f is fixed to the left end side of the upper portion b of the auxiliary device mounting stay 40c in the left-right direction, whereby the fuel filter mounting stay 40d and the auxiliary device mounting stay 40d. 40c are in a mutually reinforcing relationship. Further, the battery mounting stay 40e is constructed by vertically arranging four angles g near the front part of the base 40a.

Then, the auxiliary components of the engine 2 are attached to the radiator bracket 40 configured as described above as follows. That is, as shown in FIGS. 4 and 5, the radiator 46 is mounted on the radiator mounting stay 40b of the radiator bracket 40 while supporting the four upper, lower, left and right sides through the cushions as described above. An intercooler 34 is attached to the front of the radiator mounting stay 40b so that the intercooler 34 closes the front surface of the radiator 46 and overlaps it.

An intercooler net 49 is provided on the front surface of the intercooler 34, and the intercooler net 49 is detachably provided on the front portions of the left and right plates 50 attached to the left and right front portions of the radiator attachment stay 40b. Further, the air cleaner 48 is mounted and mounted on the mounting portion S provided on the upper portion b of the accessory mounting stay 40c so as to face the left-right direction. Further, the fuel cooler 38 is attached to the upper part b of the accessory mounting stay 40c so as to be below the air cleaner 48 in the left-right direction.

More specifically, as shown in FIGS. 6 to 8, the attachment portion on the upper side of the fuel cooler 38 is attached to the attachment portion S (the rear side plate of the attachment portion S) to which the air cleaner 48 is attached with two bolts on the left and right. Further, the left and right upper portions 51a of the fuel cooler mounting brackets 51 are attached to the mounting portions S (the left and right side plates of the mounting portions S) with bolts, and the lower mounting portions of the fuel cooler 38 are attached to the fuel cooler mounting brackets 51. Attach it to the lower part 51b with two bolts and nuts on the left and right.

Then, as described above, when the fuel cooler 38 is attached to the upper part b of the accessory mounting stay 40c through the mounting portion S and the fuel cooler mounting bracket 51 in a vertically supported state, a single member called the accessory mounting stay 40c is formed. Since the fuel cooler 38 (heat exchanger) is firmly attached to the upper portion, even if the tractor 1 sways due to unevenness of the road surface during traveling, a phase difference is unlikely to occur between the upper and lower attachment portions of the fuel cooler 38, and tentatively. The upper and lower sides of the fuel cooler 38, or the left and right mounting portions are attached to separate members, and the phase difference causes a load on the fuel cooler 38 to prevent the harmful effects of deforming or damaging the fuel cooler 38 and scattering the fuel around. You can

Further, the pre-filter 35 is attached to the fuel filter attachment stay 40d with bolts in the attachment portion e provided on the upper portion of the leg portion d in the vertical direction. The mounting plate 52 is mounted on the battery mounting stay 40e on the four angles g by bolts, and the battery 53 is mounted on the mounting plate 52 by the clamp 54, the L bolt 55, and the nut.

A stay is erected on the left end of the mounting plate 52, and the reservoir tank 56 of the radiator 46 is attached to the stay. Further, the above-mentioned ECU 32 for controlling the engine 2 is attached to the lower surface of the mounting plate 52, whereby the ECU 32 is not affected by the heat of the engine 2, and the base 40a that can come into contact with the outside air taken into the hood 5 is provided. It is arranged in the space between the mounting plate 52 and the cooling device of the special ECU 32 is unnecessary. Further, as shown in FIG. 3, the electromagnetic pump 36 is attached to the lower left side of the front side of the base 40a.

Then, the tractor 1 configured as described above starts the engine 2 and travels on the road, or reaches a field and performs plowing work by, for example, a rotary tiller. In this case, the tractor 1 is a low-speed vehicle, and unlike the case of an automobile, the outside air is rarely taken into the hood 5 by the traveling wind. However, the running wind can still be taken in from the ventilation openings 5b and 5c provided on the front side of the hood 5 to some extent.

On the other hand, the cooling fan 47 of the engine 2 sucks air on the front side of the front surface of the intercooler 34 and the fuel cooler 38, or around the upper, lower, left, and right sides thereof through the radiator 46, whereby the ventilation ports 5b, 5c, 5d provided on the bonnet 5 are drawn. The outside air is taken into the bonnet 5 from 5e and cools each air-cooled heat exchanger (fuel cooler 38, intercooler 34, radiator 46). Further, the air cleaner 48 provided above the battery 53 sucks in the air taken into the bonnet 5 through the downward intake port 48a.

Further, the pre-filter 35, the reservoir tank 56, the battery 53, and the ECU 32 which compose the auxiliary devices of the engine 2 are provided on the base 40a which is the bottom plate of the radiator bracket 409, and are positively activated by the outside air taken into the bonnet 5. Even if it cannot be said that they are cooled to, if they are higher than the temperature of the outside air taken in, they are deprived of heat by the outside air and cooled.

Further, the fuel tank 23 and the segmenter 25 provided around the floor 15, and the electromagnetic pump 36 provided on the lower surface of the base 40a that serves as the bottom plate of the radiator bracket 40 are arranged away from the engine 2 and are directly contacted with the outside air to be cooled. In the environment. Therefore, the supply pump 30, the common rail 31, the injector 33, and the main filter 37 which are provided in the engine 2 and driven by the engine 2 are not in an environment in which they are separated from the engine 2 and directly exposed to the outside air to be cooled. The two auxiliary devices can be air-cooled forcibly or indirectly as described above to sufficiently perform their respective functions.

Next, a second embodiment of the present invention will be described based on FIGS. 9 to 13. That is, the tractor 1 as the work vehicle of the second embodiment is a so-called frame vehicle in which the tractor 1 of the first embodiment includes a safety frame, whereas the tractor 1 is a cabin vehicle in which the cabin is covered with the cabin 57. .. Note that, hereinafter, the same components described in the first embodiment will be denoted by the same reference numerals in the drawings of the second embodiment, and the description thereof may be omitted.

Here, the cabin 57 that covers the control section is mounted on the vehicle body behind the engine 2 via a vibration-proof rubber. The cabin 57 includes a pair of right and left front pillars 58, a pair of left and right rear pillars, a rear pillar 59, a pair of left and right center pillars 60, and each of the six pillars extending in the vertical direction. A cabin frame is constituted by a rectangular frame-shaped roof frame 61 connecting and fixing the upper ends of 58, 59 and 60, a lower frame 62 connecting and fixing the lower ends of the columns 58, 59 and 60, and the like.

The left and right door glasses 63 are openably and closably attached to the cabin frame via hinges 64 provided on the rear side, and the front glass 65, the rear glass 66, and the door glass 63 are installed on the front side. Side glass 67 is provided at the rear. In addition, a fender 69 that covers the front upper side of the rear wheel 12 is extended from the lower end portions of the left and right rear pillars 59 toward the floor 68 side diagonally forward and downward.

Further, an inner roof and an outer roof 70 are attached to the roof frame 61, and the air inside the cabin 57 is taken in through a suction port between the inner roof and the outer roof 70, and is cooled or warmed by an evaporator or a heater core. An air conditioner unit that blows air out of the grill is installed. The cooler system of this air conditioner is composed of a compressor, a condenser 71, a receiver dryer 72, and a pipe connecting these air conditioner units to each other. Among them, the compressor compresses the gaseous refrigerant from the evaporator to obtain high temperature/high pressure. And send it to the condenser 71.

The gaseous refrigerant cooled by the condenser 71 is sent to the receiver dryer 72 while changing into a liquid refrigerant. Then, the receiver dryer 72 removes dust and water contained in the refrigerant to collect the refrigerant, and sends only the accumulated liquid refrigerant to the expansion valve of the air conditioner unit. Further, the expansion valve cools the interior of the cabin 57 by atomizing the refrigerant into a mist that easily evaporates, sending it to the evaporator, and exchanging heat with the evaporator.

Here, the compressor is attached to the engine 2, but the condenser 71 and the receiver dryer 72 are attached to the radiator bracket 40 in front of the engine 2. More specifically, as shown in FIGS. 11 to 13, the condenser 71 is provided in front of the intercooler 34 so as to overlap with the front surface thereof, and is fixed to the base 40 a of the radiator bracket 40. Attach to.

The condenser attachment stay 73 is fixed to the front ends of the left and right plates 74 attached to the radiator attachment stay 40b via a cushioning material 75 to prevent the condenser 71 from shaking. Further, the receiver dryer 72 is attached to the front part of the condenser attachment stay 73 on the right side. Further, a capacitor net 76 is provided on the front side of the capacitor 71, and the capacitor net 76 can be inserted into and removed from the left and right capacitor mounting stays 73.

On the other hand, the tractor 1 according to the second embodiment is provided with an oil cooler 77 that cools working oil that interrupts or lubricates a hydraulic clutch of the traveling transmission provided in the transmission case 4. The oil cooler 77 is attached to the radiator bracket 40 in front of the engine 2. More specifically, the oil cooler 77 is provided by effectively utilizing an empty space below the fuel cooler 38 between the condenser 71 and the battery 53, and the oil cooler 77 is mounted on the bracket 78 attached to the base 40a of the radiator bracket 40 in the left-right direction. To be installed.

The condenser 71 and the oil cooler 77 are cooled by the air sucked by the cooling fan 47 of the engine 2, like other heat exchangers (fuel cooler 38, intercooler 34, radiator 46). However, the amount of heat released from the condenser 71 is particularly large, and the temperature of the exhaust air discharged from the cooling fan 47 accordingly increases. Therefore, the temperature of the engine 2 which is air-cooled by this exhaust air also rises, the temperature of the surplus fuel discharged from the common rail 31 and the injector 33 of the engine 2 also rises, and the temperature of the fuel is reduced only by the fuel cooler 38 provided on the return side. There are cases where it cannot be lowered.

Therefore, in the second embodiment, as shown in FIG. 10, a second fuel cooler 79 is provided on the suction side for supplying fuel from the fuel tank 23 to the supply pump 30 and the like, and the fuel temperature is controlled by this fuel cooler 79. It is lowered to about 50 degrees or less to prevent damage to the electromagnetic pump 36, the supply pump 30, and the like. The second fuel cooler 79 is provided in the flow path between the prefilter 35 and the electromagnetic pump 36, water in the fuel is removed by the segmenter 25, and impurities are removed to some extent by the prefilter 35. Cool the fuel.

Further, the fuel cooler 79 on the suction side is provided in front of the front surface of the fuel cooler 38 on the return side, as shown in FIGS. 11 to 13, so that it can be easily removed or attached when necessary. To More specifically, the fuel cooler mounting bracket 51 for mounting the lower side of the return-side fuel cooler 38 includes the left and right upper mounting portions 51a mounted on the mounting portion S of the accessory mounting stay 40c and the fuel cooler as shown in FIG. A lower mounting portion 51b for mounting the lower side of 38 is provided, and a second fuel cooler mounting portion 51c is previously provided between the upper mounting portion 51a and the lower mounting portion 51b.

Then, the second fuel cooler mounting portion 51c is provided with left and right front bolts 51d fixedly attached thereto, and the left and right bolts 51d are fitted with the mounting portions provided at the lower portion of the second fuel cooler 79 to attach the nuts Attach by screwing. Therefore, the second fuel cooler 79 can also be attached while also using the bracket 51 of the fuel cooler 38 on the return side, and the cost can be suppressed.

Further, the second suction-side fuel cooler 79 only needs to slightly lower the fuel cooled entirely by the fuel stored in the return-side fuel cooler 38 and the fuel tank 23 to an allowable temperature, Along with this, the intake side fuel cooler 79 may be a small one with a smaller amount of heat radiation than the return side fuel cooler 38, so it is provided in front of the return side fuel cooler 38 to return the taken-in air (outside air). It can be first applied unobstructed by the side fuel cooler 38 to cool it effectively.

In the embodiment described above, the entire amount of surplus fuel returned from the engine 2 to the fuel tank 23 is cooled by the fuel cooler 38 on the return side. However, only the surplus fuel of the common rail 31 and the injector 33, which has a high temperature, is returned to the fuel on the return side. It may be cooled by the cooler 38, or only the surplus fuel of the common rail 31 and the injector 33, which becomes hot, may be cooled by the fuel cooler 38 on the return side and returned to the suction side of the supply pump 30 or the electromagnetic pump 36. Good.

Further, the fuel cooler 79 on the suction side may be provided in the flow path between the main filter 37 and the supply pump 30. Alternatively, although the fuel coolers 38 and 79 are attached to the auxiliary device attaching stay 40c as air-cooling type heat exchangers, an oil cooler 77 may be attached instead of the fuel coolers 38 and 79, and the present invention is limited to the above embodiment. is not.

1 tractor (work vehicle)
2 engine 5 bonnet 23 fuel tank 38 return side fuel cooler (air-cooled heat exchanger)
40 radiator bracket 40c auxiliary device mounting stay 46 radiator 48 air cleaner 53 battery 79 suction side fuel cooler (air-cooled heat exchanger)

Claims (2)

The auxiliary devices of the engine, including a radiator for cooling the engine, placed on the radiator bracket provided in front of the engine, the working vehicle to cover the said engine and auxiliaries in the bonnet, the battery in the front of the radiator bracket , also the radiator is provided on the rear erected the accessory mounting stay in the middle part between the battery and the radiator, against the top of該補device mounting stay, constituting the auxiliary components of the engine air The cleaner is on the upper side, and on the lower side, an air-cooled return-side fuel cooler that cools the excess fuel that returns from the engine to the fuel tank and an air-cooled suction-side fuel cooler that cools the fuel that is supplied from the fuel tank to the engine are installed. Thus, the work vehicle , wherein the cooler on the return side and the cooler on the suction side are configured to effectively perform heat exchange at a high position avoiding the battery. The work vehicle according to claim 1 , wherein the fuel cooler on the suction side is provided in front of the fuel cooler on the return side .