WO2005021946A1

WO2005021946A1 - Cooling device of industrial vehicle

Info

Publication number: WO2005021946A1
Application number: PCT/JP2004/011897
Authority: WO
Inventors: Tetsuji Tanaka; Masami Higaki; Kazuo Ishida
Original assignee: Tcm Corporation
Priority date: 2003-08-28
Filing date: 2004-08-19
Publication date: 2005-03-10
Also published as: JP2005069203A

Abstract

A cooling device of an industrial vehicle capable of preventing the power transmission efficiency of an engine from being lowered due to a reduction in the viscosity of hydraulic oil in a torque converter by cooling cooling water and the hydraulic oil at optimum cooling efficiency. Based on the detected temperature of the cooling water (W) in a radiator (21), the temperature of the hydraulic oil (Oc) in cylinders (10) and (11), and the temperature of the hydraulic oil (Ot) in the torque converter (27), an ATC (32) obtains the upper limit rotational speed of a cooling fan (34) and, when the rotational speed of the cooling fan (34) reaches an upper limit rotational speed, restricts the rotational speed of the cooling fan (34) so that the rotational speed does not rise beyond the upper limit rotational speed. When the rotational speed of the cooling fan (34) is within the range of the upper limit rotational speed or below, the rotational speed of the cooling fan (34) is in proportion to the rotational speed of the engine.

Description

Specification

Industrial vehicle cooling system

Technical field

[0001] The present invention includes a radiator for cooling engine cooling water, a first oil cooler for cooling hydraulic oil of a hydraulic device, and a second oil cooler for cooling hydraulic oil of a torque converter. The present invention relates to a cooling device for an industrial vehicle (for example, a wheel loader).

^ Scenic technology

Conventionally, in a wheel loader, which is an example of an industrial vehicle, a radiator that cools engine cooling water, a foil roller that cools hydraulic oil of a hydraulic device such as a cylinder, a radiator and an oil A cooling fan that supplies cooling air to the cooler is provided, and is configured so that the rotational output of the engine is transmitted to the cooling fan via a fan belt.

According to this, the rotation speed of the cooling fan depends (proportionally) only on the rotation speed of the engine, regardless of the actual temperature of the cooling water or the temperature of the hydraulic oil. Therefore, when the rotation speed of the engine increases, the rotation speed of the cooling fan also increases in proportion to this, and the rotation speed of the cooling fan increases excessively (more than necessary), and the cooling water and hydraulic oil are drained. It is difficult to cool with optimal cooling efficiency. The problem arises when the noise of the cooling fan increases. The problem arises when the fuel efficiency of the engine decreases.

As a countermeasure for such a problem, as shown in FIG. 10, a cooling fan 83 for sending cooling air to the radiator 81 and the oil cooler 82, a hydraulic motor 84 for driving the cooling fan 83, and rotation of the hydraulic motor 84 There is an industrial vehicle 90 provided with a variable displacement hydraulic pump 85 capable of controlling the speed, a coolant temperature sensor 86, a hydraulic oil temperature sensor 87, an engine speed sensor 88, and a controller 89. The controller 89 controls the discharge of the hydraulic pump 85 according to the temperatures of the cooling water and hydraulic oil detected by the temperature sensors 86 and 87 and the rotation speed of the engine 91 detected by the rotation speed sensor 88. The capacity is controlled (for example, see Patent Document 1).

According to this, the rotation speed of the cooling fan 83 depends only on the rotation speed of the engine 91. Therefore, the cooling water is controlled according to the temperature of the cooling water and the temperature of the hydraulic oil, so that the cooling water of the engine 91 and the hydraulic oil of the hydraulic device can be cooled with optimal cooling efficiency.

By the way, a vehicle equipped with an automatic transmission and capable of automatic transmission is provided with a torque converter, and in the above-mentioned conventional type, it was not possible to cool the hydraulic oil of the torque converter with optimal cooling efficiency. Therefore, there is a problem that the temperature of the hydraulic oil in the torque converter rises, the viscosity of the hydraulic oil decreases, and the power transmission efficiency of the engine 91 decreases.

Also, if the controller 89 fails, the rotation of the cooling fan 83 stops, and the cooling function is interrupted, and the engine 91 may overheat. Patent Document 1: JP 2001-182535 A

Disclosure of the invention

ADVANTAGE OF THE INVENTION This invention can cool cooling water and hydraulic oil with the optimal cooling efficiency, and can prevent that the viscosity of the hydraulic oil of a torque converter falls, and the transmission efficiency of engine power falls. It is still another object of the present invention to provide a cooling device for an industrial vehicle in which a cooling function by a cooling fan is sufficiently ensured even if a control device (controller) fails.

To achieve the above object, the first invention provides a radiator for cooling engine coolant, a water temperature detector for detecting the temperature of coolant, and a first coolant for cooling hydraulic oil of a hydraulic device. Oil cooler, a first oil temperature detector that detects the temperature of the hydraulic oil of the hydraulic device, a second oil cooler that cools the hydraulic oil of the torque converter, and the temperature of the hydraulic oil of the torque converter. A _second oil temperature detector for detection, a cooling fan for supplying cooling air to the radiator, the first and second oil coolers, and a control device are provided.

Then, the control device obtains the upper limit rotational speed of the cooling fan based on the detected cooling water temperature, the detected hydraulic oil temperature of the hydraulic device, and the detected hydraulic oil temperature of the torque converter. When the rotation speed of the fan reaches the upper limit rotation speed, the rotation speed of the cooling fan is regulated so that it does not rise above the upper limit rotation speed. Fan rotation speed> It is proportional to the rotation speed of the motor.

According to this, the rotation speed of the cooling fan increases in proportion to the rotation speed of the engine, and when the rotation speed of the cooling fan reaches the upper limit rotation speed, the rotation speed of the engine further increases. However, the rotation speed of the cooling fan does not rise above the upper limit rotation speed and is regulated to the upper limit rotation speed. This makes it possible to cool the cooling water and hydraulic oil at an optimum cooling efficiency without excessively increasing the rotation speed of the cooling fan (unnecessarily). Fuel efficiency is improved.

In addition, since the hydraulic oil of the torque converter is also cooled with the optimal cooling efficiency, it is possible to prevent a problem that occurs when the viscosity of the hydraulic oil in the torque converter decreases and the power transmission efficiency of the engine decreases. .

Also, in the second invention, the control device may include an upper limit rotation speed determined from the detected coolant temperature and an upper limit rotation speed determined from the detected hydraulic oil temperature of the hydraulic device and the detected torque converter operation. Among the upper limit rotation speeds obtained from the oil temperature, the maximum value of the upper limit rotation speed is adopted as the official upper limit rotation speed.

Further, the third invention provides a hydraulic motor that rotates a cooling fan, a pump that is operated by the power of an engine and supplies hydraulic oil for the motor to the hydraulic motor, and a motor that is supplied from the pump to the hydraulic motor. And a supply amount regulating valve device for regulating the supply amount of hydraulic oil for use. In addition, a bypass flow path that bypasses the hydraulic motor is formed in the supply flow path that supplies the motor operating oil from the pump to the hydraulic motor.

The supply amount regulating valve device includes a flow control valve that regulates the flow rate of the hydraulic fluid for the motor that flows through the bypass passage while bypassing the hydraulic motor, and a pilot pressure for switching the flow control valve to the flow control valve. It is composed of an electromagnetic pressure control valve for outputting, and a pressure reducing valve for reducing the hydraulic pressure supplied to the pressure control valve. Then, the control device outputs a control current corresponding to the upper limit rotation speed to the pressure control valve, and the pilot pressure output from the pressure control valve to the flow control valve is controlled according to the control current. .

According to this, the hydraulic oil for the motor discharged from the pump is supplied to the hydraulic motor through the supply passage, whereby the hydraulic motor operates and the cooling fan rotates. At this time, the control device outputs a control current to the pressure control valve in accordance with the determined upper limit rotational speed. The pilot pressure output from the pressure control valve to the flow control valve is controlled, and the amount of hydraulic oil supplied from the pump to the hydraulic motor increases in proportion to the increase in engine speed. As a result, the rotation speed of the hydraulic motor increases, and the rotation speed of the cooling fan is proportional to the rotation speed of the engine.

Then, when the rotation speed of the cooling fan reaches the upper limit rotation speed due to the increase in the rotation speed of the engine, a predetermined amount of hydraulic fluid for the motor is supplied to the hydraulic motor. In this state, when the rotation speed of the engine further increases and the discharge amount of the motor hydraulic oil discharged from the pump exceeds the above-mentioned predetermined amount, the flow rate is controlled by the pilot pressure output from the pressure control valve to the flow control valve. The valve is switched, and only a predetermined amount of the motor oil discharged from the pump is supplied to the hydraulic motor, and the other surplus amount is not supplied to the hydraulic motor because it flows through the bypass flow path. As a result, even if the rotation speed of the engine increases, the rotation speed of the cooling fan does not exceed the upper limit rotation speed.

Further, in the fourth invention, the upper limit rotation speed increases as the control current output to the control device pressure control valve decreases, and when the control current becomes 0, the upper limit rotation speed increases to the maximum upper limit rotation speed. It is set to become.

According to this, if the control device fails and the control current output from the control device to the pressure control valve becomes 0, the upper limit rotation speed becomes the maximum upper limit rotation speed. Insufficient rotation speed ensures a sufficient cooling function. Thus, it is possible to prevent a problem that the upper limit rotation speed is too low and the rotation speed of the cooling fan is insufficient to cause overheating.

Further, in the fifth invention, the control device is incorporated in an automatic transmission controller that automatically controls and switches the traveling speed stage of the transmission according to the traveling speed.

According to this, one automatic transmission controller can perform two types of control, that is, speed change control during driving and cooling control, thereby reducing costs.

Further, the sixth invention is provided with input means for inputting any one of a plurality of vehicle types, and display means for displaying the input vehicle type, and the control device includes an upper limit rotational speed. Is installed for each vehicle model, and the software corresponding to the vehicle model input from the input means is executed.

According to this, one type of control device can be used in common for a plurality of types of industrial vehicles, so that cost reduction can be realized.

Brief Description of Drawings

FIG. 1 is a circuit diagram of a cooling device for an industrial vehicle according to a first embodiment of the present invention.

FIG. 2 is a configuration diagram of a supply amount regulating valve device of the cooling device for an industrial vehicle.

FIG. 3 is a side view of the same wheel loader as an industrial vehicle.

FIG. 4 is a schematic plan view of a wheel loader mentioned as an industrial vehicle.

FIG. 5 is a graph showing the relationship between the control current and the temperature of cooling water and hydraulic oil of an industrial vehicle.

FIG. 6 is a graph showing the relationship between the rotation speed of an engine of an industrial vehicle and the rotation speed of a hydraulic motor.

FIG. 7 is a graph showing the relationship between the rotational speed of the engine of an industrial vehicle and the rotational speed of a hydraulic motor, in which an upper limit rotational speed set in a stepless manner according to a detected temperature is added. is there.

FIG. 8 is a side view of an industrial vehicle according to a second embodiment of the present invention, in which (a) shows a Vessenore dump, (b) shows a slag dump, and (c) shows a forklift.

FIG. 9 is a block diagram showing a configuration of an ATC of the industrial vehicle.

FIG. 10 is a circuit diagram of a conventional cooling device for an industrial vehicle.

Explanation of symbols

[0005] 1 Wheel loaders (industrial vehicles)

2 Body

5 Engine

7 Automatic transmission

10, 11 Hydraulic cylinder (hydraulic device)

21 Lajeta

22 Water temperature detector 24 First oil cooler

25 1st oil temperature detector

27 Tonoleta Converter

28 Second oil cooler

29 Second oil temperature detector

32 ATC

32a control unit

34 Cooling fan

35 hydraulic motor

37 Cooling pump

38 Supply amount regulating valve device

45 Supply channel

48 Bypass flow path

50 Flow control valve

51 Pressure control valve

61 Vessel dump (industrial vehicle)

62 Slag dump (industrial vehicle)

63 Forklift (Industrial vehicle)

65 Switch (input means)

66 Liquid crystal display (display means)

68—71 Software

Oc Hydraulic cylinder hydraulic oil

Ot Tonoreta Converter Hydraulic Fluid

Om Motor oil

Pa Pilot pressure

W cooling water

X upper limit rotation speed

Xmax Maximum upper speed limit Y control current

BEST MODE FOR CARRYING OUT THE INVENTION

[First embodiment]

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.

These figures (especially FIGS. 3 and 4) show a wheel loader 1 as an example of an industrial vehicle. The body 2 of the wheel loader 1 is provided with a plurality of wheels 3 that are rotationally driven by the driving force of the engine 5, an automatic transmission 7 that transmits the power of the engine 5 to each wheel 3, and a driving unit 6. ing. In addition, a pair of left and right booms 8, a bucket 9 provided at the tip of both booms 8, and a boom hydraulic cylinder 10 for rotating the booms 8 up and down (an example of a hydraulic device) ), A bucket hydraulic cylinder 11 (an example of a hydraulic device) that swings the bucket 9 up and down, and a hydraulic device pump 13 that supplies hydraulic oil Oc to the boom hydraulic cylinder 10 and the packet hydraulic cylinder 11. (See Fig. 1).

The operation of the boom hydraulic cylinder 10 is switched by operating a boom operation lever (not shown) provided in the operation unit 6 so that the switching valve 15 is interlocked. When the packet hydraulic cylinder 11 is moved back and forth, the switching valve 17 is switched in conjunction with the operation of a packet operation lever (not shown) provided in the operation unit 6.

As shown in FIG. 3, the operation unit 6 is provided with an external drive 40, a shift lever 41 for switching between forward and reverse, and a key switch 42 for turning on and off the main power supply of the wheel loader 1. ing. As shown in FIG. 1, the accelerator pedal 40 is mechanically linked to a throttle valve (not shown) of the engine 5 via a link mechanism 43, and the accelerator pedal 40 is depressed. In such a case, the rotation speed of the engine 5 is configured to increase in proportion to the amount of depression.

Further, the vehicle body 2 includes a radiator 21 for cooling the cooling water W of the engine 5, a water temperature detector 22 for detecting the temperature of the cooling water W, and a hydraulic oil cylinder for cooling the hydraulic cylinders 10, 11. a first oil cooler 24, a first oil temperature detector 25 for detecting the temperature of the hydraulic oil 〇_C of the hydraulic cylinder 10, 11, hydraulic oil Tonorekuko Nbata ₂ 7 which is built in the automatic transmission 7 〇 a second oil cooler 28 that cools the Pump 27 for circulating the hydraulic oil Ot between the first oil cooler 28 and the second oil cooler 28, and a second oil temperature detector 29 for detecting the temperature of the hydraulic oil Δt of the torque converter 27. A cooling fan 34 for supplying cooling air to the radiator 21 and the first and second oil coolers 24 and 28, a hydraulic motor 35 for rotating the cooling fan 34, and a hydraulic motor 35 for the motor. A cooling pump 37 that supplies hydraulic oil 〇m, a supply amount regulating valve device 38 that regulates the supply amount of motor hydraulic oil Om supplied from the cooling pump 37 to the hydraulic motor 35, and an automatic transmission controller 32 ( Hereinafter, it is referred to as ATC).

As shown in FIG. 1, the cooling pump 37 is driven by the power of the engine 5, and the rotation speed of the cooling pump 37 is proportional to the rotation speed of the engine 5. Also, as shown in FIGS. 1 and 2, the motor hydraulic oil Om discharged from the cooling pump 37 is supplied to the hydraulic motor 35 through the supply passage 45, and then discharged from the hydraulic motor 35. Then, the oil is collected in the oil tank 47 through the return flow path 46. Further, a bypass channel 48 that bypasses the hydraulic motor 35 is formed in the middle of the supply channel 45, whereby a part of the motor operating oil Om flowing through the supply channel 45 is It is not supplied to the motor 35 but can be bypassed to the return flow path 46 through the bypass flow path 48.

The supply amount regulating valve device 38 includes a flow control valve 50 (closed state CL in a normal state) for adjusting the flow rate of the hydraulic oil O m flowing through the bypass flow path 48 and a flow control valve 50 in the opening direction OP. A pressure control valve 51 that outputs a pilot pressure for switching to the flow control valve 50 and a source pressure of the pilot pressure that is output from the pressure control valve 51 to the flow control valve 50 to a constant pressure suitable for the pilot control. And a pressure reducing valve 52 for adjusting the pressure to a value. The pressure control valve 51 is a proportional solenoid valve (electric pressure control valve), and adjusts the source pressure of the pressure reducing valve 52 as a pilot pressure and outputs the pilot pressure to the flow control valve 50.

Further, in the middle of the supply passage 45, pilot lines 53 and 54 for switching the flow control valve 50 are provided, and a pressure difference between before and after the orifice 55 is detected.

Next, the control function of the ATC 32 will be described.

The ATC32 uses an automatic transmission according to the traveling speed of the wheel loader 1. Automatically switches the traveling speed stage of 7 to 1st gear and 4th speed, and further performs traveling speed stage control of switching the automatic transmission 7 between forward and backward in response to the operation of the shift lever 41. That is, the ATC 32 switches the automatic transmission 7 to the first gear during excavation and climbing, switches to the second gear when starting, automatically shifts up to the third and fourth gears as the traveling speed increases, and conversely decreases Shift down automatically from 4th gear.

Further, the ATC 32 incorporates a control device 32a having the following cooling fan control function.

That is, the control device 32a obtains the upper limit rotation speed X of the cooling fan 34 and the control current Y corresponding to the upper limit rotation speed X in the following steps (1) and (4).

(1) The temperature of the cooling water W detected by the water temperature detector 22 is A / D converted and converted into a digital value Z1.Based on the converted value Z1, the first upper limit of the cooling fan 34 is obtained. The rotation speed XI and the first control current Y1 corresponding to the rotation speed XI are obtained.

(2) The temperature of the hydraulic oil Oc detected by the first oil temperature detector 25 is A / D converted to a digital value Z2, and the second upper limit of the cooling fan 34 is determined based on the converted value Z2. The rotation speed X2 and the second control current Y2 corresponding to the rotation speed X2 are obtained.

(3) The temperature of the hydraulic oil Ot detected by the second oil temperature detector 29 is A / D converted to a digital value Z3, and the third upper limit of the cooling fan 34 is determined based on the converted value Z3. The rotation speed X3 and the third control current Y3 corresponding to the rotation speed X3 are obtained.

(4) The maximum value of the first to third upper limit rotational speeds XI—X3 obtained in (1)-(3) above is adopted as the official upper limit rotational speed X, Find the control current Y corresponding to the upper limit rotational speed X.

As shown in the graph of FIG. 5, the temperatures of the cooling water W and the hydraulic oil Oc and Ot detected by the detectors 22, 25 and 29, and the first to third control currents Y1 to Y3 Is inversely related. At this time, the first to third control currents Y1 to Y3 are respectively calculated by the following equations.

Yl = Al -Ln (Xl) -Bl

Y2 = A2 -Ln (X2) -B2

Y3 = A3 -Ln (X3) -B3 The above Al—A3 and Bl—B3 are constants.

For reference, Table 1 below shows the values of the upper limit rotational speed XI—X3 for each temperature of the cooling water W of the radiator 21 and the hydraulic oil Ot of the torque converter 27 and the hydraulic oil O c of the hydraulic cylinders 10 and 11. . The value of the upper limit rotation speed between the temperatures has a proportional relationship.

[table 1]

Then, as shown in FIG. 2, the control device 32a outputs a control current Y corresponding to the upper limit rotational speed X obtained in the above procedure (4) to the pressure control valve 51, and the control current Y The proportional pilot pressure Pa is output from the pressure control valve 51 to the flow control valve 50.

Hereinafter, the cooling control in the above configuration will be described.

As shown in FIG. 1, the cooling pump 37 is driven to rotate by the engine 5, and the hydraulic oil Om for the motor discharged from the cooling pump 37 is supplied to the hydraulic motor 35 through the supply passage 45, and thereafter, The oil is collected in the oil tank 47 through the return passage 46. As a result, the hydraulic motor 35 operates to rotate the cooling fan 34, and the cooling fan 34 supplies cooling air to the radiator 21 and the first and second oil coolers 24 and 28.

The graph in Fig. 6 shows the rotation speed of the engine 5 (= corresponding to the discharge amount of the hydraulic oil Om discharged from the cooling pump 37) and the rotation speed of the hydraulic motor 35 (= the motor supplied to the hydraulic motor 35). (Corresponding to the supply amount of hydraulic oil 〇m).

According to this, when the driver depresses the accelerator pedal 40 to increase the rotation speed of the engine 5 from the minimum rotation speed Lo during idling, the discharge amount of the cooling pump 37 is proportional to the rotation speed of the engine 5. The supply amount of the hydraulic fluid Om supplied to the hydraulic motor 35 increases. As a result, the oil is increased in proportion to the rotation speed of the engine 5. The rotation speed of the pressure motor 35 increases.

At this time, as shown in FIG. 2, the pilot pressure Pa output from the pressure control valve 51 and the differential pressure Pb between the inlet side (upstream side) and the outlet side (downstream side) of the orifice 55 flow through the flow control valve 50. Acts as pilot pressure (= pilot pressure Pa + differential pressure Pb) for switching from closing direction CL to opening direction OP. The differential pressure Pb is equal to the pilot pressure supplied from the first pilot line 53 to the flow control valve 50 and the pilot pressure supplied from the second pilot line 54 to the flow control valve 50. (= Pilot pressure from the first pilot line 53-pilot pressure from the second pilot line 54).

As the rotation speed of the engine 5 increases, the discharge amount of the cooling pump 37 increases, and the differential pressure Pb increases. When the rotation speed of the engine 5 reaches the predetermined rotation speed Re and the value obtained by adding the pilot pressure Pa and the differential pressure Pb becomes the predetermined pressure P (Pa + Pb = P), the flow control valve 50 Switches to the opening direction 〇P. As a result, a part of the motor hydraulic oil Om flowing through the supply flow path 45 is bypassed to the return flow path 46 through the bypass flow path 48, so that the pressure difference Pb between the inlet side and the outlet side of the orifice 55 becomes a predetermined pressure. The upper limit of the differential pressure Pb is restricted to the above-mentioned predetermined value (= P-Pa) without increasing above a predetermined value (= P-Pa) obtained by subtracting the pilot pressure Pa from P. As a result, as shown in FIG. 6, when the rotation speed of the engine 5 is in the range from the predetermined rotation speed Re to the maximum rotation speed H, the differential pressure Pb between the inlet side and the outlet side of the orifice 55 becomes the predetermined value. (= P_Pa), only a predetermined amount of the motor oil Om discharged from the cooling pump 37 is supplied to the hydraulic motor 35, and the other excess amount passes through the bypass passage 48. To the return channel 46. Thus, the rotation speed of the hydraulic motor 35 is regulated to a predetermined rotation speed Rm, and the predetermined rotation speed Rm corresponds to the upper limit rotation speed X of the cooling fan 34.

For example, if the temperature of the cooling water W and the temperature of the hydraulic oil Oc, Ot detected by the detectors 22, 25, 29 increase, the value of the control current Y decreases in inverse proportion to this, and the pressure control valve The pilot pressure Pa output from 51 to the flow control valve 50 also decreases. As a result, the predetermined value (= P_Pa) increases, so that the differential pressure Pb between the inlet side and the outlet side of the orifice 55 increases, and accordingly, as shown in FIG. Speed Re increases. As a result, a larger amount of motor hydraulic oil Om is supplied to the hydraulic motor until the specified pressure P is reached. As a result, the predetermined rotation speed Rm of the hydraulic motor 35, that is, the upper limit rotation speed X of the cooling fan 34, increases.

Conversely, when the temperature of the cooling water W and the temperature of the hydraulic oil 〇c, Ot detected by each of the detectors 22, 25, 29 decrease, the value of the control current Y increases in inverse proportion to this, and the pressure The pilot pressure Pa output from the control valve 51 to the flow control valve 50 also increases. As a result, the predetermined value (= P_Pa) becomes smaller, so that the pressure difference Pb between the inlet side and the outlet side of the orifice 55 becomes smaller, and accordingly, as shown in FIG. Speed Re decreases. As a result, the amount of motor hydraulic oil Om that can be supplied to the hydraulic motor 35 until the predetermined pressure P is reached is reduced. As a result, the predetermined rotation speed Rm of the hydraulic motor 35, that is, the upper limit rotation speed X of the cooling fan 34 is reduced. Decreases.

From the above, when the rotation speed of the cooling fan 34 reaches the upper limit rotation speed X, even if the rotation speed of the engine 5 further increases, the rotation speed of the cooling fan 34 exceeds the upper limit rotation speed X. It is restricted to the upper limit rotation speed X without rising. As a result, the cooling water W and the hydraulic oils 〇c, Ot can be cooled at an optimum cooling efficiency without excessively increasing the rotation speed of the cooling fan 34 (unnecessarily). And the fuel efficiency of Engine 5 improves.

Since the hydraulic oil 〇t of the torque converter 27 is also cooled at the optimum cooling efficiency, if the viscosity of the hydraulic oil Ot in the torque converter 27 decreases and the transmission efficiency of the power of the engine 5 decreases, the following problem occurs. Can be prevented.

Also, as shown in FIG. 7, the upper limit rotational speed X of the cooling fan 34 is stepless according to the temperature of the cooling water W and the temperature of the hydraulic oil Oc, Δt detected by each of the detectors 22, 25, and 29. Therefore, the cooling water W and the hydraulic oils 〇c, Ot can be cooled with more optimal cooling efficiency according to the situation.

Also, if the control device 32a fails and the control current Y output from the control device 32a to the pressure control valve 51 becomes 0, the pilot pressure output from the pressure control valve 51 to the flow control valve 50 Pa becomes 0. Thus, when the pressure difference Pb between the inlet side and the outlet side of the orifice 55 reaches the predetermined pressure P (Pb = P), the flow control valve 50 switches to the opening direction ΔP. In this case, the maximum amount of motor oil Om that can be supplied from the supply passage 45 to the hydraulic motor 35 is the maximum. As a result, as shown by a point A in FIG. 7, the predetermined rotation speed Rm of the hydraulic motor 35, that is, the upper limit rotation speed X of the cooling fan 34 becomes the maximum upper limit rotation speed Xmax. As a result, a sufficient cooling function that ensures that the rotation speed of the cooling fan 34 is not short is sufficiently ensured, thereby preventing a problem that the upper limit rotation speed X is too low and the rotation speed of the cooling fan 34 is insufficient to cause overheating. Can be fail safe.

Furthermore, since the control device 32a having the cooling fan control function as described above is incorporated in the ATC32, two types of control, that is, shift control during traveling and cooling control, can be performed with one ATC32, and cost is reduced. Down can be achieved.

[Second Embodiment]

Next, a second embodiment will be described with reference to FIGS.

Industrial vehicles include, besides the wheel loader 1 described above, for example, as shown in FIG. 8, a vessel dump 61 for carrying shears, a slag dump 62 for carrying slag, etc. of a steelworks, a forklift 63 for carrying containers, etc. Exists. A unique model number is set for each of the wheel loader 1, the vessel dump 61, the slag dump 62, and the forklift 63. In addition, the values of the slope, the upper limit rotation speed X, the control current Y, the predetermined pressure P, and the like of the graph shown in FIG. 7 are different for each of the plurality of vehicle types (wheel loader 1, vessel dump 61, slag dump 62, forklift 63). Is different.

As shown in FIG. 9, the ATC 32 includes a switch 65 (an example of an input unit) for inputting a model number of any one of the plurality of vehicle types, and a model number of the input vehicle type. A liquid crystal display section 66 (an example of a display means) for displaying is provided.

Further, the ATC 32 includes a plurality of software programs 68-71 for obtaining the upper limit rotational speed X for each vehicle model, and a software program corresponding to the model number of the vehicle model entered at the switch 65 (ie, the first to fourth software programs 68). 71) having a function of selecting and executing one of them.

According to this, when the vehicle type of the industrial vehicle is the wheel loader 1, the operator operates the switch 65 and inputs the model number of the wheel loader 1. As a result, the model number of the wheel loader 1 is displayed on the liquid crystal display section 66, the first software 68 corresponding to the wheel loader 1 is selected and executed, and the cooling fan 34 is connected to the control device 32 built in the ATC 32. controlled by a.

In the case of the vessel dump 61, operating the switch 65 and inputting the model number of the vessel dump 61 causes the model number of the vessel dump 61 to be displayed on the liquid crystal display 66, and the second corresponding to the vessel dump 61. The software 69 is selected and executed, and the cooling fan 34 is controlled by the control device 32a built in the ATC32. Similarly, in the case of the slug dump 62, by inputting the model number of the slug dump 62, the third software 70 corresponding to the slug dump 62 is selected and executed, and in the case of the forklift 63, the model number of the forklift 63 is input. Then, the fourth software 71 corresponding to the forklift 63 is selected and executed. As a result, one type of ATC32 can be used in common for a plurality of types of industrial vehicles, so that further cost reduction can be realized.

[Other embodiments]

In the above-described first embodiment, as shown in FIG. 1, the force that incorporates the second oil cooler 28 in the radiator 21 The second oil cooler 28 is individually installed outside the radiator 21. May be.

In the first embodiment described above, the hydraulic cylinders 10 and 11 may be cited as examples of the hydraulic apparatus, and other hydraulically driven cargo handling apparatuses may be used.

In the first embodiment, the first upper limit rotational speed XI obtained from the detected temperature of the cooling water W and the second upper limit rotational speed X2 obtained from the detected temperature of the hydraulic oil Oc are used. And the third upper-limit rotation speed X3 determined from the detected temperature of the hydraulic oil Ot, the largest upper-limit rotation speed is adopted as the official upper-limit rotation speed X. Of the temperature of the cooling water W and the temperature of the hydraulic oils 〇c and 〇t, the upper limit rotational speed determined from the highest temperature may be adopted as the official upper limit rotational speed X.

In the second embodiment, as an example of the industrial vehicle, a vehicle having a wheel loader 1, a Bessenore dump 61, a slag dump 62, and a forklift 63 may be another type of vehicle.

Industrial applicability

As described above, according to the present invention, the rotation speed of the cooling fan increases excessively (unnecessarily). The cooling water and hydraulic oil can be cooled with optimal cooling efficiency, reducing the noise of the cooling fan and improving the fuel efficiency of the engine.

In addition, since the hydraulic oil of the torque converter is also cooled with the optimum cooling efficiency, it is possible to prevent a trouble that occurs when the viscosity of the hydraulic oil in the torque converter decreases and the power transmission efficiency of the engine decreases.

Furthermore, even if the control device fails and the control current output from the control device to the supply regulating valve device becomes zero, the cooling function is sufficiently ensured, and the rotation speed of the cooling fan is reduced. Insufficiency such as overheating due to shortage can be prevented. In addition, the cost can be reduced by incorporating the control device into the automatic transmission controller, and the cost can be further reduced by externally changing the control value for each type of industrial vehicle.

Claims

The scope of the claims

[1] A radiator that cools the cooling water of the engine, a water temperature detector that detects the temperature of the cooling water, a first oil cooler that cools the hydraulic oil of the hydraulic device, and a hydraulic oil of the hydraulic device A first oil temperature detector for detecting the temperature, a second oil cooler for cooling the hydraulic oil for the torque converter, a second oil temperature detector for detecting the temperature of the hydraulic oil for the torque converter, and the A cooling fan for supplying cooling air to the first and second oil coolers, and a control device,

The control device obtains an upper limit rotation speed of the cooling fan based on the detected cooling water temperature, the detected hydraulic oil temperature of the hydraulic device, and the detected hydraulic oil temperature of the torque converter. When the rotation speed reaches the upper limit rotation speed, regulate the rotation speed of the cooling fan so that it does not rise above the upper limit rotation speed.

A cooling device for an industrial vehicle, wherein the rotation speed of the cooling fan is proportional to the rotation speed of the engine when the rotation speed of the cooling fan is equal to or lower than the upper limit rotation speed.

[2] The control device determines the upper limit rotation speed obtained from the detected coolant temperature, the upper limit rotation speed obtained from the detected hydraulic oil temperature of the hydraulic device, and the detected hydraulic oil temperature of the torque converter. 2. The cooling device for an industrial vehicle according to claim 1, wherein a maximum value of the maximum rotation speed among the maximum rotation speeds obtained from the above is adopted as a formal maximum rotation speed.

[3] A hydraulic motor that rotates the cooling fan, a pump that operates with the power of the engine and supplies hydraulic oil for the motor to the hydraulic motor, and a supply amount of hydraulic oil for the motor that is supplied from the pump to the hydraulic motor. A supply flow rate regulating valve device for regulating, a bypass flow path for bypassing the hydraulic motor is formed in a supply flow path for supplying the hydraulic fluid for the motor from the pump to the hydraulic motor,

The supply amount regulating valve device outputs a flow control valve that regulates the flow rate of the hydraulic fluid for the motor that flows through the bypass passage by bypassing the hydraulic motor, and outputs a pilot pressure for switching the flow control valve to the flow control valve. And a pressure reducing valve for reducing the hydraulic pressure supplied to the pressure control valve.

The control device outputs a control current corresponding to the upper limit rotation speed to the pressure control valve. 3. The cooling device for an industrial vehicle according to claim 1, wherein a pilot pressure output from the pressure control valve to the flow control valve is controlled according to the control current.

[4] As the control current output from the control device to the pressure control valve decreases, the upper limit rotation speed increases, and when the control current becomes 0, the upper limit rotation speed becomes the maximum upper limit rotation speed. 4. The cooling device for an industrial vehicle according to claim 3, wherein the cooling device is set.

[5] The automatic transmission controller according to any one of claims 1 to 4, wherein the control device is incorporated in an automatic transmission controller that automatically controls and switches the traveling speed stage of the transmission according to the traveling speed. 3. The cooling device for an industrial vehicle according to claim 1.

[6] Input means for inputting any one of the plurality of vehicle types and display means for displaying the input vehicle type are provided,

6. The control device according to claim 1, wherein the control device includes a plurality of software programs for obtaining an upper limit rotational speed for each vehicle model, and executes software corresponding to the vehicle model input from the input unit. The cooling device for an industrial vehicle according to any one of the above.