Engine type industrial vehicle

Abstract

To provide an engine type industrial vehicle which can remove dust in a hydraulic oil cooler without moving the oil cooler even when a cooling fan, a radiator, and the hydraulic oil cooler are juxtaposed.SOLUTION: An engine type industrial vehicle includes: a vehicle body; a radiator 40 mounted on the vehicle body to cool a coolant for an engine 31; a blower which is mounted on the vehicle body to generate cooling air to the radiator 40; and a hydraulic oil cooler 41 installed between the radiator 40 and the blower in an air blowing direction of the blower. The engine type industrial vehicle includes: a dust estimation mechanism which estimates a state of dust adhering to the hydraulic oil cooler 41; an air volume controller 61 which may increase or decrease an air volume of the cooling air blown to the hydraulic oil cooler 41; and a controller which is connected to the dust estimation mechanism and controls the air volume controller 61. The controller controls the air volume controller 61 so as to increase or decrease the volume of air blown to the hydraulic oil cooler 41 according to the state of dust estimated by the dust estimation mechanism.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to an engine-powered industrial vehicle. [Background technology]

[0002] As a conventional technique for engine-powered industrial vehicles, for example, the cooling structure for an industrial vehicle disclosed in Patent Document 1 is known. In the cooling structure for an industrial vehicle disclosed in Patent Document 1, a cooling fan, a radiator, and an oil cooler are arranged side by side. The oil cooler is supported by a member so that it can rotate freely in the vertical direction along the surface of the radiator. The cooling structure for an industrial vehicle disclosed in Patent Document 1 is said to make it possible to easily clean and remove dirt and dust that has accumulated between the oil cooler and the radiator or that has adhered to the oil cooler, etc. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-146089 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the cooling structure for an industrial vehicle disclosed in Patent Document 1 requires components to allow the oil cooler to rotate up and down along the surface of the radiator, resulting in problems such as an increased number of parts and a complex structure. It also requires space for the oil cooler to rotate, and rotating the oil cooler when cleaning is required is cumbersome. Furthermore, if the oil cooler becomes large, a great deal of effort is required to rotate the oil cooler.

[0005] The present invention has been made in consideration of the above problems, and an object of the present invention is to provide an engine-powered industrial vehicle that allows dust to be removed from the hydraulic oil cooler without moving the hydraulic oil cooler, even if the cooling fan, radiator, and hydraulic oil cooler are installed side by side. [Means for solving the problem]

[0006] In order to solve the above problems, the present invention provides an engine-powered industrial vehicle having a vehicle body, a radiator mounted on the vehicle body and cooling engine coolant, a blower mounted on the vehicle body and generating cooling air for the radiator, and a hydraulic oil cooler installed downstream of the radiator in the blowing direction of the blower and cooling hydraulic oil, the vehicle having a dust estimation mechanism that estimates the state of dust adhering to the hydraulic oil cooler, an air volume regulator that can increase or decrease the volume of cooling air for the hydraulic oil cooler, and a controller connected to the dust estimation mechanism and controlling the air volume regulator, wherein the controller controls the air volume regulator to increase or decrease the air volume for the hydraulic oil cooler depending on the state of dust estimated by the dust estimation mechanism.

[0007] In this invention, the dust estimation mechanism estimates the state of dust adhering to the hydraulic oil cooler, and the controller controls the air volume regulator to increase or decrease the air volume to the hydraulic oil cooler in accordance with the state of dust estimated by the dust estimation mechanism. As a result, the air volume of cooling air to the hydraulic oil cooler is increased or decreased in accordance with the state of dust adhering to the hydraulic oil cooler, and the cooling air can remove dust adhering to the hydraulic oil cooler.

[0008] Furthermore, in the above-described engine-powered industrial vehicle, the dust estimation mechanism may be a differential pressure detector that detects the pressure difference between the upwind side and the downwind side of the hydraulic oil cooler, and the controller may be configured to operate the air volume regulator to increase the air volume to the hydraulic oil cooler when the differential pressure detected by the differential pressure detector is equal to or greater than a threshold value. In this case, the dust estimation mechanism is a differential pressure detector that detects the pressure difference between the upwind and downwind sides of the hydraulic oil cooler. The controller operates the air volume regulator to increase the air volume to the hydraulic oil cooler when the differential pressure detected by the differential pressure detector is equal to or greater than a threshold. When the differential pressure detected by the differential pressure detector is equal to or greater than the threshold, the controller can estimate that a large amount of dust has adhered to the hydraulic oil cooler, and by increasing the volume of cooling air, it can make it easier to remove dust.

[0009] In the engine-powered industrial vehicle described above, the controller may be configured to stop operation of the air volume regulator when the differential pressure falls below a threshold value. In this case, the controller stops the operation of the air flow regulator when the differential pressure falls below the threshold value, so there is no need to operate the air flow regulator when there is little dust adhesion to the hydraulic oil cooler, preventing unnecessary power consumption.

[0010] In addition, in the above-mentioned engine-powered industrial vehicle, the air volume regulator may be configured to include a movable plate member that is installed downstream of the radiator in the air blowing direction and that can change the direction of the cooling air, and an actuator that is controlled by the controller and displaces the movable plate member. In this case, the direction of the cooling air is changed by displacing the movable plate member with the actuator. By displacing the movable plate member and changing the direction of the cooling air, the volume of the cooling air can be increased or decreased.

[0011] Furthermore, the above-mentioned engine-powered industrial vehicle may be configured to include a radiator screen installed upstream of the radiator in the air blowing direction, a shroud that holds the radiator screen and houses the hydraulic oil cooler, and an axial member that is axially supported on the radiator or the shroud and holds the movable plate member. In this case, the radiator screen is held by the shroud on the upstream side of the radiator in the airflow direction, and the shaft member that holds the movable plate member is journaled on the radiator or the shroud, making it easier to adjust the volume of cooling air upstream of the hydraulic oil cooler.

[0012] Furthermore, in the above-described engine-powered industrial vehicle, the dust estimation mechanism may be a temperature sensor that detects the temperature of the hydraulic oil in the hydraulic oil cooler, and the controller may be configured to operate the air volume regulator to increase the air volume to the hydraulic oil cooler when the temperature detected by the temperature sensor is equal to or higher than a threshold value. In this case, the dust estimation mechanism is a temperature sensor that detects the temperature of the hydraulic oil in the hydraulic oil cooler. When the temperature detected by the temperature sensor is equal to or higher than a threshold, the controller operates the air volume regulator to increase the air volume to the hydraulic oil cooler. Therefore, the dust condition can be estimated from the hydraulic oil in the hydraulic oil cooler, and when a large amount of dust has adhered to the hydraulic oil cooler, the amount of cooling air to the hydraulic oil cooler can be increased. [Effects of the Invention]

[0013] According to the present invention, an engine-powered industrial vehicle can be provided that allows dust to be removed from the hydraulic oil cooler without moving the oil cooler, even if the cooling fan, radiator, and hydraulic oil cooler are installed side by side. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a side view of an engine-powered forklift according to a first embodiment. [Figure 2] FIG. 1 is a perspective view schematically showing a main part of an engine-powered forklift. [Figure 3] FIG. 1 is an exploded perspective view showing a schematic view of a main part of an engine-powered forklift truck. [Figure 4] 1 is a side view schematically showing a main part of an engine-powered forklift truck. FIG. [Figure 5] 1 is a schematic diagram of an engine-powered forklift truck. [Figure 6] FIG. 1( a ) is a side view showing a schematic view of the main parts of an engine-powered forklift when the differential pressure is less than a threshold value, and FIG. 1( b ) is a side view showing a schematic view of the main parts of an engine-powered forklift when the differential pressure is greater than or equal to the threshold value. [Figure 7] FIG. 10 is an exploded perspective view schematically showing a main part of an engine-powered forklift according to a second embodiment. [Figure 8] FIG. 10 is a side view schematically showing an air volume regulator according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0015] (First embodiment) An engine-powered industrial vehicle according to an embodiment of the present invention will be described below with reference to the drawings. The engine-powered industrial vehicle of this embodiment is an engine-powered forklift truck as a cargo handling vehicle. Note that the terms "front / back," "left / right," and "up / down" that specify directions are based on the position of a forklift operator seated in the driver's seat and facing the forward direction of the forklift truck.

[0016] As shown in Figures 1 and 2, the forklift 10 is provided with a loading / unloading device 12 as a working device at the front of a vehicle body 11. A driver's seat 13 is provided near the center of the vehicle body 11. Front wheels 14 are provided at the front of the vehicle body 11, and rear wheels 15 are provided at the rear of the vehicle body 11. The front wheels 14 are drive wheels, and the rear wheels 15 are steered wheels. A counterweight 16 is provided at the rear of the vehicle body 11, and the counterweight 16 is used to adjust the vehicle weight and achieve weight balance in the vehicle body 11. The counterweight 16 has a space (not shown) that penetrates in the fore-and-aft direction, and this space forms an air flow path. The vehicle body 11 is provided with a head guard 17 that covers the top of the driver's seat 13.

[0017] The cargo handling apparatus 12 is equipped with a mast 18 having outer masts 19 and inner masts 20. The pair of left and right outer masts 19 are equipped with a pair of left and right inner masts 20 that can be raised and lowered inside the outer masts 19. The cargo handling apparatus 12 is equipped with a lift bracket 21 that rises and falls along the inner masts 20, and the lift bracket 21 is equipped with a pair of left and right forks 22 and a backrest 23. The left and right forks 22 scoop up and support a load. The backrest 23 supports the rear of the load supported by the pair of left and right forks 22.

[0018] A tilt cylinder 24 operated by hydraulic oil is installed between the vehicle body 11 and the cargo handling device 12. Operation of the tilt cylinder 24 causes the cargo handling device 12 to tilt in the front-to-rear direction with the lower end of the cargo handling device 12 as a fulcrum. The outer mast 19 is provided with a lift cylinder 25 that operates by supplying and discharging hydraulic oil (see Figure 1). Operation of the lift cylinder 25 causes the inner mast 20 to rise and fall inside the outer mast 19, and also raises and lowers the lift bracket 21.

[0019] A steering column 27 that supports a steering wheel 28 is provided in front of the driver's seat 13. An engine 31 is mounted on the vehicle body 11, and the vehicle body 11 is provided with an openable engine hood 32 that covers the engine 31. A driver's seat 33 is provided on the engine hood 32.

[0020] A shroud 35 is provided behind the engine 31 on the vehicle body 11. As shown in FIG. 2, the shroud 35 is a cylindrical body formed from a metal plate and attached to the vehicle body 11. One opening of the shroud 35 is located forward, and the other opening of the shroud 35 is located rearward. The rear opening of the shroud 35 faces the counterweight 16. The shroud 35 has an upper plate portion 36, a bottom plate portion 37, and a pair of left and right side plate portions 38. The shroud 35 is attached to a radiator 40, which will be described next, and the shroud 35 houses a hydraulic oil cooler 41.

[0021] The radiator 40 cools the engine 31 coolant by exchanging heat with the air. As shown in FIG. 3 , the radiator 40 has an inlet 42 that takes in the coolant from the engine 31, a radiator main body 43 that cools the coolant, and an outlet 44 that sends the cooled coolant to the engine 31. The inlet 42 is connected to a coolant pipe (not shown) that passes the coolant supplied from the engine 31. The radiator main body 43 has multiple cooling flow paths (not shown) that pass the coolant taken in at the inlet 42 and multiple fins (not shown) that dissipate heat from the coolant in the cooling flow paths. The radiator main body 43 has multiple gaps (not shown) that allow the flow of cooling air. The outlet 44 is connected to a coolant pipe (not shown) that returns the cooled coolant to the engine 31. The radiator 40 is fixed to a mounting portion (not shown) provided on the vehicle body 11 so as to substantially cover the front opening of the shroud 35. Only the upper plate portion 36 of the shroud 35 extends forward, and the upper portion of the radiator 40 is covered by the upper plate portion 36 .

[0022] 3 and 4, a radiator screen 45 is installed in front of the radiator 40. The radiator screen 45 is a mesh-like member that prevents clogging of the gaps in the radiator 40 with dust. The radiator screen 45 is fixed to the shroud 35.

[0023] The hydraulic oil cooler 41 cools the hydraulic oil that operates the cargo handling device 12 by heat exchange with air. As shown in FIG. 3, the hydraulic oil cooler 41 has a structure similar to that of the radiator 40, and includes an inlet 46 for taking in hydraulic oil, a cooler main body 47 for cooling the hydraulic oil, and an outlet 48 for dissipating the cooled hydraulic oil. The inlet 46 is connected to a hydraulic pipe (not shown) through which hydraulic oil supplied from a hydraulic oil circuit (not shown) passes. The cooler main body 47 has multiple cooling oil passages (not shown) through which the hydraulic oil taken in by the inlet 46 passes, and multiple fins (not shown) for dissipating heat from the hydraulic oil in the cooling oil passages. The cooler main body 47 has multiple gaps formed therein to allow the flow of cooling air. The outlet 48 is connected to a hydraulic pipe (not shown) through which the cooled hydraulic oil returns to the hydraulic oil circuit.

[0024] The hydraulic oil cooler 41 is fixed to the shroud 35 at an upper rear part of the radiator 40. As shown in FIG. 4, the hydraulic oil cooler 41 is located above the center of the radiator 40 in the up-down direction. A gap 49 is formed between the hydraulic oil cooler 41 and the radiator 40 in the front-to-rear direction. In addition, a gap 50 is formed between the hydraulic oil cooler 41 and the upper plate portion 36 of the shroud 35. The formation of the gap 50 allows cooling air to pass above and below the hydraulic oil cooler 41.

[0025] A cooling fan 51 is installed behind the hydraulic oil cooler 41 so as to cover the rear opening of the shroud 35. The cooling fan 51 is a blower that generates cooling air from the front to the rear of the radiator 40. As shown in FIG. 3, the cooling fan 51 has a fan body 52 and a frame 53 that rotatably supports the fan body 52. ​​The fan body 52 has a rotary shaft 54 ​​journaled to the frame 53 and a plurality of rotary vanes 55 provided on the rotary shaft 54. As shown in FIG. 4, a belt pulley 56 is provided at the rear end of the rotary shaft 54. The engine 31 has an engine shaft 57 that extends rearward from the crankshaft (not shown) and is journaled on the vehicle body 11, and a belt pulley 58 is provided at the rear end of the engine shaft 57. A transmission belt 59 is wrapped around the belt pulleys 56 and 58. Therefore, the cooling fan 51 is operated by the power of the engine 31. Operation of the cooling fan 51 generates cooling air that flows from the radiator 40 to the hydraulic oil cooler 41 from the front to the rear.

[0026] The forklift 10 of this embodiment includes a differential pressure detector 60 that detects the pressure difference between the upwind and downwind sides of the hydraulic oil cooler 41, and an air volume regulator 61 that adjusts the volume of cooling air that passes through the radiator 40 and flows to the hydraulic oil cooler 41. The differential pressure detector 60 includes a detector main body 62, a front measurement unit 63 that measures the air pressure P1 on the upwind side of the hydraulic oil cooler 41, and a rear measurement unit 64 that measures the air pressure P2 on the downwind side of the hydraulic oil cooler 41. The differential pressure detector 60 outputs a signal representing the differential pressure (ΔP = P1 - P2) between the air pressure P1 measured by the front measurement unit 63 and the air pressure P2 measured by the rear measurement unit 64. It can be estimated that the larger the differential pressure ΔP detected by the differential pressure detector 60, the greater the amount of dust adhering to and accumulating on the hydraulic oil cooler 41. The differential pressure detector 60 is connected to a controller 65 , and the controller 65 receives a signal from the differential pressure detector 60 .

[0027] The controller 65 is mounted on the vehicle body 11 and controls each part of the vehicle body 11, and is also connected to various sensors. As shown in FIG. 5, the controller 65 includes a CPU 66 as an arithmetic processing unit and a storage unit 67 composed of a RAM, a ROM, etc. The controller 65 may include dedicated hardware that executes at least a part of various processes, for example, an application specific integrated circuit (ASIC). The controller 65 can be configured as a circuit including one or more processors that operate according to a computer program, one or more dedicated hardware circuits such as an ASIC, or a combination thereof.

[0028] A threshold value Pt of the differential pressure △P is preset in the controller 65. When the differential pressure △P detected by the differential pressure detector 60 is less than the threshold value Pt (△P < T), the controller 65 determines that there is little dust adhering to and accumulating on the hydraulic oil cooler 41. On the other hand, when the differential pressure △P detected by the differential pressure detector 60 is greater than or equal to the threshold value Pt (△P ≧ T), the controller 65 determines that there is a large amount of dust adhering to and accumulating on the hydraulic oil cooler 41. When the differential pressure △P detected by the differential pressure detector 60 is greater than or equal to the threshold value Pt, the air volume regulator 61 is controlled to increase the air volume of the cooling air for the hydraulic oil cooler 41. The differential pressure detector 60 corresponds to a dust estimation mechanism that estimates the state of dust adhering to the hydraulic oil cooler 41.

[0029] Next, the air volume regulator 61 will be described. The air volume regulator 61 can increase or decrease the volume of cooling air supplied to the hydraulic oil cooler 41. As shown in FIG. 3 , the air volume regulator 61 includes a movable plate member 68, a shaft member 69, and an electric motor 70. The movable plate member 68 is a rectangular plate member provided at the upper rear of the radiator 40 and is rotatable around the shaft member 69. That is, the shaft member 69 is journaled to the radiator 40, and the movable plate member 68 is held by the shaft member 69. The axis of the shaft member 69 extends in the left-right direction. The electric motor 70 corresponds to an actuator that rotates the shaft member 69 and displaces the movable plate member 68. The displacement of the movable plate member 68 may be changed continuously or in steps depending on the dust level, thereby adjusting the volume of cooling air continuously or in steps. In this embodiment, the shaft member 69 is journaled to the radiator 40, but it may also be journaled to the upper plate portion 36 of the shroud 35, for example.

[0030] As shown in FIG. 6( a), the movable plate member 68 is normally substantially parallel to the upper plate portion 36 of the shroud 35. In this state, cooling air can pass through the gap 50 between the upper plate portion 36 of the shroud 35 and the hydraulic oil cooler 41. When the differential pressure ΔP detected by the differential pressure detector 60 is equal to or greater than the threshold value Pt, the controller 65 operates the electric motor 70 in the forward direction. As shown in FIG. 6( b), the movable plate member 68 is displaced by the operation of the electric motor 70 so that the cooling air does not pass through the gap 50 between the upper plate portion 36 of the shroud 35 and the hydraulic oil cooler 41. Specifically, the movable plate member 68 is displaced so that the rear end of the movable plate member 68 is positioned at the front upper end of the hydraulic oil cooler 41. This increases the amount of cooling air flowing to the hydraulic oil cooler 41, making it easier to blow away dust that has adhered to and accumulated on the hydraulic oil cooler 41.

[0031] When the differential pressure ΔP detected by the differential pressure detector 60 drops from equal to or greater than the threshold value Pt to less than the threshold value Pt, the controller 65 operates the electric motor 70 in reverse rotation. The operation of the electric motor 70 displaces the movable plate member 68 so that the cooling air passes through the gap 50 between the upper plate portion 36 of the shroud 35 and the hydraulic oil cooler 41. Specifically, the movable plate member 68 is displaced so that the rear end of the movable plate member 68 is positioned at the front upper end of the hydraulic oil cooler 41. As a result, the movable plate member 68 becomes approximately parallel to the upper plate portion 36 of the shroud 35, and the cooling air passes through the gap 50 between the upper plate portion 36 of the shroud 35 and the hydraulic oil cooler 41.

[0032] Next, the operation of the forklift 10 according to this embodiment will be described. When the forklift 10 is operated, the engine 31 is driven. The engine shaft 57 rotates as the engine 31 is driven, and the cooling fan 51 is operated via the belt pulleys 56, 58 and the transmission belt 59. When the cooling fan 51 is operating, cooling air is generated that flows from the front of the radiator screen 45 toward the cooling fan 51. Incidentally, when the cooling fan 51 is operating, air is drawn in from the front and bottom of the vehicle body 11 toward the engine 31 at the rear, and the drawn air flows into the radiator screen 45 and the radiator 40. The air flowing toward the engine 31 becomes cooling air that passes through the radiator 40.

[0033] As the cooling air passes through the radiator screen 45, relatively large dust particles are removed from the cooling air by the radiator screen 45. The cooling air that has passed through the radiator screen 45 contains dust particles that could not be removed by the radiator screen 45. The cooling air that has passed through the radiator screen 45 passes through the radiator 40 and exchanges heat with the coolant. The coolant in the radiator 40 is cooled by heat exchange with the cooling air. Note that when the cooling air passes through the radiator 40, some of the dust remaining on the cooling air may adhere to and accumulate on the radiator 40. Dust that has adhered to and accumulated on the radiator 40 can be removed by opening the engine hood 32 when the engine 31 is stopped and, for example, blowing compressed air from an air nozzle onto the radiator 40.

[0034] A portion of the cooling air that has passed through the radiator 40 passes through the hydraulic oil cooler 41. The cooling air that has passed through the radiator 40 also passes through the hydraulic oil cooler 41 and exchanges heat with the hydraulic oil. The hydraulic oil in the hydraulic oil cooler 41 is cooled by heat exchange with the cooling air. The cooling air that has passed through the hydraulic oil cooler 41 passes through the cooling fan 51 and is then discharged to the outside through the space inside the counterweight 16.

[0035] Incidentally, since cooling air passes through the hydraulic oil cooler 41, dust remaining in the cooling air may adhere to and accumulate on the hydraulic oil cooler 41. Because the hydraulic oil cooler 41 is installed inside the shroud 35, it is difficult to directly blow compressed air injected from an air nozzle onto the hydraulic oil cooler 41, as is the case with the radiator 40. However, in this embodiment, the amount of cooling air flowing to the hydraulic oil cooler 41 is adjusted, making it easier to remove dust adhering to the hydraulic oil cooler 41.

[0036] As the amount of dust adhering to the hydraulic oil cooler 41 increases, the pressure difference ΔP between the air pressure P1 on the upstream side of the hydraulic oil cooler 41 and the air pressure P2 on the downstream side increases due to pressure loss caused by the accumulation of dust. If the pressure difference ΔP is less than the threshold value Pt, the controller 65 determines that there is little dust adhering to and accumulating in the hydraulic oil cooler 41. Therefore, as shown in Figure 6(a), the air volume regulator 61 is not activated, the movable plate member 68 is positioned in a substantially horizontal position, and the volume of cooling air to the hydraulic oil cooler 41 does not increase.

[0037] When the differential pressure ΔP exceeds the threshold value Pt, the controller 65 determines that a large amount of dust has adhered to and accumulated on the hydraulic oil cooler 41. Therefore, the controller 65 activates the airflow regulator 61. Specifically, the controller 65 controls the electric motor 70 to rotate and tilt the movable plate member 68 around the shaft member 69 as a pivot point. As shown in FIG. 6( b), when the movable plate member 68 is displaced and tilted, the cooling air that previously passed through the gap 50 between the hydraulic oil cooler 41 and the upper plate portion 36 of the shroud 35 now passes through the hydraulic oil cooler 41, increasing the amount of cooling air passing through the hydraulic oil cooler 41. The increased amount of cooling air passing through the hydraulic oil cooler 41 makes it easier to remove dust adhering to the hydraulic oil cooler 41 compared to when the amount of cooling air is not increased. Furthermore, the increased amount of cooling air passing through the hydraulic oil cooler 41 makes it more difficult for dust remaining in the cooling air to adhere to the hydraulic oil cooler 41.

[0038] Dust removed from the hydraulic oil cooler 41 passes rearward through the cooling fan 51 together with the cooling air and is discharged to the outside through the space inside the counterweight 16. When the differential pressure ΔP detected by the differential pressure detector 60 drops from equal to or greater than the threshold value Pt to less than the threshold value Pt, the controller 65 controls the electric motor 70 to return the movable plate member 68 to its original position. When the movable plate member 68 returns to its original position, the air volume regulator 61 stops operating.

[0039] The forklift 10 according to this embodiment has the following advantages. (1) The dust estimation mechanism estimates the state of dust adhering to the hydraulic oil cooler 41, and the controller 65 controls the air volume regulator 61 to increase or decrease the air volume to the hydraulic oil cooler 41 in accordance with the state of dust estimated by the dust estimation mechanism. Therefore, the air volume of cooling air to the hydraulic oil cooler 41 is increased or decreased in accordance with the state of dust adhering to the hydraulic oil cooler 41, and the cooling air can remove dust adhering to the hydraulic oil cooler 41.

[0040] (2) The dust estimation mechanism is a differential pressure detector 60, which detects the differential pressure ΔP between the upwind side and downwind side of the hydraulic oil cooler 41. When the differential pressure ΔP detected by the differential pressure detector 60 is equal to or greater than a threshold value Pt, the controller 65 operates the air volume regulator 61 to increase the air volume to the hydraulic oil cooler 41. When the differential pressure ΔP detected by the differential pressure detector 60 is equal to or greater than the threshold value Pt, the controller 65 can estimate that a large amount of dust has adhered to the hydraulic oil cooler 41, and by increasing the air volume of the cooling air, it is possible to more easily remove dust from the hydraulic oil cooler 41. Furthermore, increasing the air volume makes it more difficult for dust remaining in the cooling air to adhere to the hydraulic oil cooler 41.

[0041] (3) The controller 65 stops the operation of the air volume regulator 61 when the differential pressure ΔP becomes less than the threshold value Pt, so there is no need to operate the air volume regulator 61 when there is little dust adhesion to the hydraulic oil cooler 41, preventing unnecessary power consumption. Also, by stopping the operation of the air volume regulator 61, it is possible to prevent the hydraulic oil in the hydraulic oil cooler 41 from being overcooled.

[0042] (4) The air volume regulator 61 is installed downstream of the radiator 40 in the air blowing direction and has a movable plate member 68 that can change the direction of the cooling air, and an electric motor 70 that is controlled by the controller 65 and serves as an actuator that displaces the movable plate member 68. The direction of the cooling air is changed by displacing the movable plate member 68 by the electric motor 70. By displacing the movable plate member 68 and changing the direction of the cooling air, the volume of the cooling air can be increased or decreased.

[0043] (5) The hydraulic oil cooler 41 includes a radiator screen 45 installed upstream of the radiator 40 in the airflow direction, a shroud 35 that holds the radiator screen 45 and houses the hydraulic oil cooler 41, and a shaft member 69 that is pivotally supported by the radiator 40 and holds a movable plate member 68. The radiator screen 45 is held by the shroud 35 upstream of the radiator 40 in the airflow direction, and the shaft member 69 that is pivotally supported by the radiator 40 and holds the movable plate member 68 is installed, making it easier to adjust the amount of cooling air upstream of the hydraulic oil cooler 41. Furthermore, if the hydraulic oil cooler 41 is housed within the shroud 35, it is difficult to remove dust that accumulates in front of the hydraulic oil cooler 41, even if compressed air is sprayed from an air nozzle, for example. However, increasing the amount of cooling air makes it possible to remove dust and prevent dust from accumulating.

[0044] (6) The volume of the cooling air generated by the cooling fan 51 increases from the center of the cooling fan 51 toward the radially outer side. The air volume regulator 61 directs a portion of the cooling air from above downward (toward the radially inner side) in the upper area where the volume of air is large by displacing the movable plate member 68, so that the volume of the cooling air passing through the hydraulic oil cooler 41 can be effectively increased.

[0045] (Second embodiment) Next, a forklift according to a second embodiment will be described. In this embodiment, the dust estimation mechanism is different from that of the first embodiment. In this embodiment, the same configuration as in the first embodiment will be referred to and the same reference numerals will be used.

[0046] 7, the forklift 80 of this embodiment has a temperature sensor 81 that detects the temperature T1 of the hydraulic oil in the hydraulic oil cooler 41. The temperature sensor 81 corresponds to a dust estimation mechanism and is connected to the controller 65. When dust adheres to and accumulates in the hydraulic oil cooler 41, the cooling capacity of the hydraulic oil cooler 41 decreases and the temperature T1 of the hydraulic oil rises, so the controller 65 can estimate the state of the dust that has adhered to and accumulated in the hydraulic oil cooler 41.

[0047] When the temperature T1 of the hydraulic oil detected by the temperature sensor 81 is less than the threshold value Tt (T1 < Tt), the controller 65 determines that there is little dust adhering to and accumulating on the hydraulic oil cooler 41. On the other hand, when the temperature T1 detected by the temperature sensor 81 is greater than or equal to the threshold value Tt (T1 ≥ Tt), the controller 65 determines that there is a large amount of dust adhering to and accumulating on the hydraulic oil cooler 41. When the temperature T1 detected by the temperature sensor 81 is greater than or equal to the threshold value Tt, the air volume regulator 61 is controlled to increase the air volume of the cooling air for the hydraulic oil cooler 41.

[0048] In this embodiment, the dust estimation mechanism is the temperature sensor 81 that detects the temperature of the hydraulic oil at the outlet portion 48 of the hydraulic oil cooler 41. When the temperature T1 detected by the temperature sensor 81 is greater than or equal to the threshold value Tt, the controller 65 operates the air volume regulator 61 to increase the air volume for the hydraulic oil cooler 41. Therefore, the state of the dust can be estimated based on the hydraulic oil in the hydraulic oil cooler 41, and when the amount of dust adhering to the hydraulic oil cooler 41 is large, the air volume of the cooling air for the hydraulic oil cooler 41 can be increased.

[0049] (Modification example) Next, the modification example will be described. The air volume regulator 90 of this modification example shown in FIG. 8 has a movable plate member 91 and an electric motor 92 as an actuator. A slit 93 through which the movable plate member 91 can be inserted is formed in the upper plate portion 36 of the shroud 35. The movable plate member 91 is a plate member that is inclined with respect to the air blowing direction. The electric motor 92 slides the movable plate member 91 so that the movable plate member 91 protrudes and retracts between the upper plate portion 36 of the shroud 35 and the hydraulic oil cooler 41. The electric motor 92 is controlled by the controller 65.

[0050] When there is little dust adhering to the hydraulic oil cooler 41, the movable plate member 91 is positioned above the upper plate portion 36 of the shroud 35. When there is a lot of dust adhering to the hydraulic oil cooler 41, the movable plate member 91 is slid downward and rearward by operation of the electric motor 92, preventing the passage of cooling air through the gap 50 and increasing the amount of cooling air to the hydraulic oil cooler. When there is little dust adhering to the hydraulic oil cooler 41, the movable plate member 91 is positioned outside the shroud 35, so dust is less likely to adhere to the movable plate member 91.

[0051] The present invention is not limited to the above-described embodiment, and various modifications are possible within the scope of the spirit of the invention. For example, the following modifications may be made.

[0052] In the above embodiment, an engine-powered industrial vehicle is described as an engine-powered forklift, but the invention is not limited to this. The engine-powered industrial vehicle may be a cargo handling vehicle equipped with an engine other than an engine-powered forklift, or may be an engine-powered construction vehicle. In the above embodiments, a differential pressure detector or a temperature sensor for detecting hydraulic oil temperature was used as an example of the dust estimation mechanism, but this is not limited thereto. The dust estimation mechanism may be a mechanism for detecting the temperature difference between the inlet and outlet temperatures of the hydraulic oil cooler, and the dust state may be estimated based on the magnitude of the temperature difference. In particular, as the amount of dust adhering to and accumulating in the hydraulic oil cooler increases, the temperature difference between the inlet and outlet temperatures of the hydraulic oil cooler decreases. Therefore, the dust state may be determined by setting a threshold value for the temperature difference. In this way, the dust estimation mechanism is not particularly limited as long as it is a means for estimating the dust state. In the above embodiment, the air flow regulator is provided on the top of the radiator or the top of the shroud, but this is not limitative. The air flow regulator may be provided at any position, for example, near the center of the radiator in the vertical direction. In the above embodiment, the air flow regulator has a movable plate member and an electric motor as an actuator for displacing the movable plate member. However, this is not limited to this. The air flow regulator may use a member other than a movable plate member. Furthermore, the actuator may be a fluid pressure cylinder or an electromagnetic solenoid other than an electric motor. In the above embodiment, the cooling fan is installed behind the hydraulic oil cooler. However, the present invention is not limited to this. The cooling fan may be installed in front of the radiator screen, for example. In this case, the hydraulic oil cooler installed downstream of the radiator does not necessarily have to be housed in the shroud. For example, the hydraulic oil cooler may be installed in the space inside the counterweight. [Explanation of symbols]

[0053] 10 Forklifts (engine-powered industrial vehicles) 11 Body 12 Cargo handling equipment 13 Driver's seat 16 Counterweight 22 Fork 31 Engine 33 Driver's seat 35 Shroud 40 Radiator 41 Hydraulic oil cooler 45 Radiator Screen 49, 50 gap 51 Cooling fan (blower) 60 Differential pressure detector (dust estimation mechanism) 61, 90 Air volume regulator 65 Controller 68, 91 Movable plate member 69 Shaft 70, 92 Electric motor (actuator) P1, P2 air pressure △P differential pressure Pt, Tt threshold 80 forklift 81 Temperature sensor (dust estimation mechanism) T1 temperature

Claims

1. The car body and a radiator mounted on the vehicle body to cool engine coolant; a blower mounted on the vehicle body to generate cooling air for the radiator; a hydraulic oil cooler that is installed downstream of the radiator in the air blowing direction of the blower and that cools hydraulic oil, a dust estimation mechanism that estimates the state of dust adhering to the hydraulic oil cooler; an air volume regulator that can increase or decrease the volume of cooling air for the hydraulic oil cooler; a controller connected to the dust estimation mechanism and controlling the air volume regulator; The engine-powered industrial vehicle is characterized in that the controller controls the air volume regulator so as to increase or decrease the air volume to the hydraulic oil cooler in accordance with the dust state estimated by the dust estimation mechanism.

2. the dust estimation mechanism is a differential pressure detector that detects a pressure difference between an upwind side and a downwind side of the hydraulic oil cooler, 2. The engine-powered industrial vehicle according to claim 1, wherein the controller operates the air volume regulator to increase the air volume to the hydraulic oil cooler when the differential pressure detected by the differential pressure detector is equal to or greater than a threshold value.

3. 3. The engine-powered industrial vehicle according to claim 2, wherein the controller stops operation of the air volume regulator when the differential pressure falls below a threshold value.

4. The air volume regulator is a movable plate member disposed downstream of the radiator in the airflow direction, and capable of changing the direction of the cooling air; 3. The engine-powered industrial vehicle according to claim 1, further comprising an actuator controlled by the controller to displace the movable plate member.

5. a radiator screen disposed upstream of the radiator in the air blowing direction; a shroud that holds the radiator screen and houses the hydraulic oil cooler; 5. The engine-powered industrial vehicle according to claim 4, further comprising a shaft member that is journaled on the radiator or the shroud and that holds the movable plate member.

6. the dust estimation mechanism is a temperature sensor that detects the temperature of the hydraulic oil in the hydraulic oil cooler, 2. The engine-powered industrial vehicle according to claim 1, wherein the controller operates the air volume regulator to increase the air volume to the hydraulic oil cooler when the temperature detected by the temperature sensor is equal to or higher than a threshold value.

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