This invention relates to a cooling structure for a working vehicle having an oil cooler.
A known cooling structure for a working vehicle having a water-cooled engine includes a cooling fan driven by the engine for cooling a radiator. Cooling air flows generated by the cooling fan are supplied to the radiator and an oil cooler opposed to the radiator to cool oil (see JP 2007-9825, for example).
In the above construction, the working vehicle has the water-cooled engine requiring many accessories such as the radiator and a water pump. Thus, the working vehicle tends to become large and costly.
The object of this invention is to provide a cooling structure for cooling oil without increasing the size and cost of a working vehicle.
A cooling structure for a working vehicle, according to this invention, with a transmission disposed rearwardly and downwardly of a driver's seat and having a hydrostatic transmission, and an air-cooled engine disposed rearwardly of the transmission, comprises a fan for cooling the engine and a fan for cooling the transmission mounted on a rotary shaft operatively connecting the transmission with an output shaft of the air-cooled engine, the fans being configured such that air flows generated by the fans move from adjacent the transmission toward the engine; an oil cooler for cooling fluid supplied to the hydrostatic transmission, the oil cooler being disposed between the fan for cooling the engine and the fan for cooling the transmission, and disposed to face each of the fans; and an air guiding plate disposed at a position higher than the oil cooler for guiding air to regions of the fans.
With this characteristic construction, instead of installing a water-cooled engine which requires many accessories such as a radiator and a water pump, oil stored in the change speed devices and oil passing through the oil cooler can be cooled by cooling air flows generated by the fan for cooling the change speed devices.
Therefore, the oil can be cooled without increasing the size and cost of the working vehicle.
An embodiment in which this invention is applied to a riding type mowing machine which is one example of working vehicles will be described hereinafter.
The vehicle body 1 includes a front frame 6 formed of square pipe or the like and disposed in a front part thereof. The front frame 6 supports the link mechanism 4, and has right and left front wheels 2 arranged at right and left ends of a front end thereof to be dirigible about vertical axes. The link mechanism 4 can raise and lower the mower 5 in parallel by operation of a single-acting hydraulic cylinder 7.
The front frame 6 has a boarding step 8 formed of sheet metal and covering substantially the whole of the front frame 6 from above. The boarding step 8 has a rubber mat (not shown) laid over the surface thereof, and has, arranged in a middle front region thereof, a brake pedal 9 biased back to a non-braking position, and a lock pedal 10 for engaging and holding the brake pedal 9 in a braking position against the biasing force. A positionally adjustable driver's seat 11 is disposed rearwardly and upwardly of the boarding step 8. Fenders 12 and shift levers 13 are arranged at right and left sides of the driver's seat 11, respectively. An arch-like protection frame 14 is erected at the back of the driver's seat 11. Thus, this riding type mowing machine has a driving platform 15 formed on a front portion of the vehicle body 1.
As shown in
A transmission device (an example of change speed devices) 20 is disposed forwardly and downwardly of the engine 19 for slowing down power from the engine 19 and dividing the power into propelling power and working power. The transmission device 20 houses a clutch (not shown) for connecting and disconnecting the working power. Hydrostatic stepless transmissions (which are one example of change speed device, hereinafter abbreviated as HSTs) 21 are arranged at right and left sides of the transmission device 20 for receiving the propelling power from the transmission device 20. A reduction gear 22 is connected to an outer side of each HST 21 for receiving the power after a change speed by the corresponding HST 21. Each reduction gear 22 has a corresponding one of the rear wheels 3 drivably attached thereto. Each HST 21 has a shift rod (not shown) interlocked to a corresponding one of the shift levers 13 to be shiftable in response to forward and rearward rocking of the corresponding shift lever 13.
With this construction, the right and left shift levers 13 are rockable forward and rearward to shift the HST 21 corresponding to each control lever 13. In this way, the right and left rear wheels 3 can be driven at variable speed independently of each other.
That is, this riding type mowing machine has the right and left front wheels 2 dirigible in a follow-up mode, and the right and left rear wheels 3 drivable at variable speed independently of each other. Consequently, the mowing machine can produce, as desired, a stopping state with the right and left rear wheels 3 stopped, a straight moving state with the right and left rear wheels 3 driven at equal speed forward or backward, a large radius turn state with the right and left rear wheels 3 driven at different speeds forward or backward, a pivot turn state with one of the right and left rear wheels 3 stopped and the other driven forward or backward, and a spin turn state with one of the right and left rear wheels 3 driven forward and the other backward,
The transmission device 20 has a PTO shaft 20A mounted in a lower front position thereof for taking the working power out for the mower 5. The PTO shaft 20A transmits the working power from the transmission device 20 to the mower 5 through a telescopic transmission shaft 23 and universal joints 24 attached to opposite ends of the transmission shaft 23. That is, the mower 5 receives constant-speed power irrespective of traveling speed and running state.
The rear frame 16 includes a rear cover 25 disposed at the rear end thereof and having right and left side walls 25A and a rear wall 25B. A plurality of exhaust holes 25a are formed in the rear wall 25B of the rear cover 25. An upper cover 26 covering an upper portion of the engine 19 from above is connected to the rear cover 25 to be pivotable open and close about an upper end of rear cover 25. The upper cover 26 has a plurality of exhaust holes 26a formed in a rear wall 26A thereof. A partition wall 28 is erected on the front wall 18B of the support deck 18 for forming an engine room 27 with the rear frame 16, rear cover 25 and upper cover 26. In the engine room 27, an air cleaner 29 is disposed above the engine 19. A muffler 30 is disposed rearwardly of the engine 19.
Maintenance of the air cleaner 29 such as changing of elements can be carried out easily by opening the upper cover 26 (see
Though not shown, the rear frame 16 includes a holding mechanism holding the rear cover 25 in a closed position.
As shown in
A sleeve shaft 19E is connected to the front end of the cooling fan 19C to be rotatable with the cooling fan 19C about the output shaft 19A. The sleeve shaft 19E supports a circular, porous dust-proof plate 19F for preventing inflow of dust from the air intake 19a of the air guide housing 19D to the interior of the housing 19D caused by the sucking action of the cooling fan 19C.
As shown in
This construction can prevent ambient air containing a large quantity of grass clippings and the like from being drawn from under the vehicle body toward the air intake 19a of the air guide housing 19D as cooling air by the sucking action of the cooling fan 19C. Instead, ambient air containing a less quantity of grass clippings and the like can be supplied as cooling air from above the vehicle body through between the driver's seat 11 and partition wall 28 toward the air intake 19a of the air guide housing 19D.
As a result, the quantity of dust such as grass clippings adhering to or depositing on and around the engine 19 can be reduced drastically, to reduce the time and trouble taken in cleaning.
As shown in
Though not shown, the dust removing cover 34 may be formed separately from the upper cover 26, and detachably erected on the rear frame 16.
As shown in
With this construction, dust having deposited on an inner surface of the lid 32D can be removed easily through the opening 32b of the bottom wall 32A, by opening the upper cover 26 to move the dust removing cover 34 away from the rear frame 16, and operating the control rod 32G to open the lid 32D. Dust having deposited on an inner surface of the dust-proof plate 32 can be removed easily through the opening 32b of the bottom wall 32A by holding the lid 32D in the open position.
As shown in
The transmission device 20 has, mounted on a lower rear portion thereof a hydraulic pump 39 for sucking and feeding under pressure oil (or fluid) stored inside the transmission device 20, and a first oil filter 40 of the cartridge type for filtering the oil sucked by the hydraulic pump 39. The oil fed under pressure by the hydraulic pump 39 can be supplied to the hydraulic cylinder 7 for vertically moving the mower, right and left HSTs 21 and clutch by operation of a control valve (not shown) and the like. Oil drained from the hydraulic cylinder 7 for vertically moving the mower, right and left HSTs 21 and clutch is returned to the interior of the transmission device 20. A second oil filter 41 of the cartridge type is mounted on an upper front portion of the transmission device 20 for filtering the oil supplied to the right and left HSTs 21.
Maintenance of the first oil filter 40 such as changing of elements can be carried out easily through the opening 32b of the bottom wall 32A by operating the control rod 32G to hold the lid 32D in the open position (see
Between the partition wall 28 and cooling fan 38 for the change speed devices, an oil cooler 42 is disposed for cooling fluid supplied in circulation to the transmission device 20, hydraulic cylinder 7, right and left HSTs 21 and clutch. The oil cooler 42 is formed to extend to the ambient air introducing space 33 from between the engine cooling fan 19C and cooling fans 38 for the change speed devices, and have lower portions straddling the universal joint 37 so that considerable portions thereof overlap the cooling fan 38 for the change speed devices when seen in the fore and aft direction.
Thus, upper portions of the oil cooler 42 are supplied with engine cooling air flowing through the ambient air introducing space 33 into the air intake 19a of the air guide housing 19D by the sucking action of the cooling fan 19C opposed to the oil cooler 42. Lower portions of the oil cooler 42 can be supplied with cooling air for the change speed devices having flowed around the transmission device 20 and right and left HSTs 21 by the sucking action of the cooling fan 38 for the change speed devices.
The partition wall 28 includes a pair of right and left first air guiding plates 28A arranged adjacent right and left ends of the oil cooler 42, a pair of right and left second air guiding plates 28B sloping inward and downward from lower edges of the respective first air guiding plates 28A toward the air intake 18a of the support deck 18, and a third air guiding plate 28C extending between the right and left first air guiding plates 28A and sloping rearward and downward from above the oil cooler 42 toward the air intake 18a of the support deck 18.
Thus, the right and left first air guiding plate 28 can prevent the heat of the engine room 27 from being drawn in through the air intake 19a of the air guide housing 19D by the sucking action of the engine cooling fan 19C. The right and left second air guiding plates 28B and third air guiding plate 28C can form an cooling air guide passage 43 extending from between the driver's seat 11 and partition wall 28 to the air intake 19a of the air guide housing 19D, such that the passage 43 is tapered to become narrower from a region adjacent the cooling fan 38 for the change speed devices which is upstream in the flowing direction of cooling air, to a region adjacent the engine cooling fan 19C which is downstream in the flowing direction of cooling air. This increases the speed of the cooling air passing through the air passage 43 of the cooling air, to increase the flow rate per unit time of the cooling air supplied to the engine 19 and oil cooler 42. As a result, the engine 19, and the oil cooler 42 located in the air passage 43, can be cooled efficiently by the cooling air.
The third air guiding plate 28C is detachably attached to the partition wall 28 by engaging a pair of right and left engaging claws 28b formed by bending rear ends of the third air guiding plate 28C, into a pair of right and left slits 28a formed in the partition wall 28. By removing the third air guiding plate 28C from the partition wall 28, replenishment of grease for the sleeve shaft 19E and universal joint 37 located under the third air guiding plate 28C may be carried out easily through grease nipples 19b and 37a of the sleeve shaft 19E and universal joint 37. Dust adhering to the dust-proof plate 19F, oil cooler 42 and so on may also be removed easily after removing the third air guiding plate 28C from the partition wall 28 (see
As shown in
Though not shown, the third air guiding plate 28C may be attached to the partition wall 28 to be pivotable between an operative position extending from the partition wall 28 to the upper end of the oil cooler 42, and a retracted position standing along the partition wall 28. The partition wall 28 may have an engaging device for engaging the third air guiding plate 28C to retain the third air guiding plate 28C in the retracted position.
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Though not shown, metal fittings for supporting the air cleaner 29 may be attached to an upper rear surface of the partition wall, so that the air cleaner 29 may be disposed on the upper rear surface of the partition wall 28.
[1]The working vehicles to which this invention is applicable include a mid-mount mower having a mower unit 5 disposed between right and left front wheels 2 and right and left rear wheels 3 of a four-wheel drive type vehicle body 1, a front mower, a tractor, a riding type rice planting machine and so on.
[2]The oil cooler 42 may be disposed opposite the cooling fan 38 for the change speed devices across the change speed devices 20 and 21.
[3]The oil cooler 42 may be disposed opposite the cooling fan 38 for the change speed devices without straddling the universal joint 37.
Number | Date | Country | Kind |
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2007-145983 | May 2007 | JP | national |