JP6097549B2 - Hydraulic drive cooling fan control system, hydraulic drive cooling fan control method, and industrial vehicle - Google Patents

Description

  The present invention relates to a hydraulically driven cooling fan control system, a hydraulically driven cooling fan control method, and an industrial vehicle.

  In an industrial vehicle such as a wheel loader, a working mechanism including a steering device and a boom is operated by operating a hydraulic circuit for a working mechanism including a hydraulic pump and the like by using rotational energy of an engine mounted on the vehicle body as power. The Further, the vehicle body is provided with a cooling fan for cooling various cooling objects. In the field of industrial vehicles, in order to achieve the desired rotation control of the cooling fan without depending on the rotation control of the engine, it is usually driven by a fan hydraulic motor instead of the engine drive cooling fan directly connected to the engine. Hydraulically driven cooling fans are used. Specifically, a hydraulically driven cooling fan and a fan hydraulic circuit including a fan hydraulic motor and a fan hydraulic pump are mounted on the vehicle body. The fan hydraulic circuit rotates the hydraulically driven cooling fan by rotating the fan hydraulic motor via the fan hydraulic pump as the engine rotates. Various cooling objects such as engine cooling water for cooling the engine, hydraulic oil for operating the fan hydraulic motor, and the like are cooled by the air rotation of the hydraulically driven cooling fan.

  For example, in Patent Document 1, a steady rotation speed, a low speed rotation speed, and a high speed rotation speed of a hydraulically driven cooling fan are set for each engine rotation speed, such as engine load, engine cooling water temperature, hydraulic oil temperature, etc. According to various factors, the optimum fan rotation speed is selected from the fan rotation speeds set as described above, and the fan hydraulic pump is switched to the fan hydraulic motor so that the selected fan rotation speed is executed. It is disclosed that the rotational speed of a fan hydraulic motor is controlled by operating an electromagnetic proportional control valve that adjusts the flow rate of the hydraulic oil.

International Publication No. 2007/026627

  By the way, the hydraulically driven cooling fan is connected to the engine by a fan hydraulic pump and constantly discharges hydraulic pressure, and operates using the hydraulic pressure. For this reason, the hydraulically driven cooling fan continues without stopping the blowing rotation while the engine is operating. Therefore, when the rotational speed of the cooling fan is controlled according to the temperature of the cooling target such as engine cooling water or hydraulic oil as in Patent Document 1, the rotational speed of the hydraulically driven cooling fan is set to the minimum rotational speed. By simply setting and reducing the cooling capacity of the hydraulically driven cooling fan, there is a possibility that overcooling of the cooling target may occur depending on the temperature of the outside air.

  The present invention has been made to solve such problems, and an object thereof is to prevent overcooling of a cooling target by a hydraulically driven cooling fan.

In order to achieve the above object, a hydraulically driven cooling fan control system according to an aspect of the present invention is rotatable in the forward and reverse rotation directions, takes in outside air, cools the object to be cooled by the outside air, A hydraulically driven cooling fan that reduces the air volume to the cooling target when the rotational direction is the reverse rotation, and a rotational direction switch that switches the rotational direction of the hydraulically driven cooling fan between the forward rotation and the reverse rotation. A valve, a rotational speed control valve that controls the rotational speed of the hydraulically driven cooling fan, a temperature detector that detects the temperature of the cooling target, and a temperature detected by the temperature detector is higher than a lower threshold temperature , said direction of rotation of the hydraulically driven cooling fan outputs the rotation direction command to the rotation direction switching valve so that the forward rotation, detected by said temperature detector temperature In response to the first control for outputting a rotational speed command for adjusting the rotational speed of the hydraulically driven cooling fan to the rotational speed control valve, and when the temperature detected by the temperature detector is lower than a lower threshold temperature Is rotated so that the rotational direction of the hydraulically driven cooling fan is the reverse rotation in a state where the rotational speed command is output to the rotational speed control valve so that the rotational speed of the hydraulically driven cooling fan becomes the minimum rotational speed. And a control device that performs a second control for outputting a direction command to the rotation direction switching valve.

  According to the above configuration, in addition to setting the rotational speed of the hydraulically driven cooling fan to the minimum rotational speed when the detected temperature of the cooling target becomes lower than the lower limit threshold temperature (for example, below freezing point) due to the temperature drop of the outside air or the like. Then, the hydraulically driven cooling fan is switched from forward rotation to reverse rotation to reduce the air volume to the cooling object compared to the normal rotation. As a result, it is possible to further reduce the cooling capacity of the hydraulically driven cooling fan and prevent overcooling of the cooling target.

  In the hydraulic drive cooling fan control system, the cooling target includes a plurality of cooling targets, and the temperature detector includes a plurality of temperature detectors for each cooling target, and the control device detects each of the temperature detections. The second control may be performed when at least one of the temperatures detected by the vessel is lower than the corresponding lower threshold temperature.

  According to the above configuration, in a system in which a plurality of objects to be cooled are cooled by a hydraulically driven cooling fan, if the temperature of at least one object to be cooled becomes lower than the lower threshold temperature due to a temperature drop of outside air, the hydraulically driven cooling fan By setting the rotation speed to the minimum rotation speed and performing control to switch from forward rotation to reverse rotation, it is possible to prevent overcooling of all of the plurality of cooling objects.

  In the hydraulic drive cooling fan control system, the control device is configured such that at least one temperature among the plurality of temperatures detected by the temperature detectors is higher than an upper limit threshold temperature while performing the second control. When it becomes, it is good also as switching from said 2nd control to said 1st control.

  According to the above configuration, the cooling capacity of the hydraulically driven cooling fan is reduced by setting the rotational speed of the hydraulically driven cooling fan to the minimum rotational speed and controlling the hydraulically driven cooling fan from normal rotation to reverse rotation. If the temperature of at least one cooling target becomes higher than the upper threshold temperature under the situation, the cooling of the cooling target by the hydraulically driven cooling fan can be resumed by canceling the above-described control.

  In the hydraulically driven cooling fan control system, switching means for manually switching between the first control and the second control in the control device of the hydraulically driven cooling fan regardless of the temperature detected by the temperature detector. It is good also as having.

  According to the above configuration, the operator can switch the control of the hydraulically driven cooling fan to manual operation based on the temperature of the outside air and the detected temperature of the fluid.

  The hydraulically driven cooling fan control system includes an engine, a radiator, engine cooling water as the cooling target, and the engine cooling water cooled by the radiator by supplying the engine cooling water from the engine to the radiator. And an engine cooling water cooling mechanism that circulates the engine cooling water so as to return the engine cooling water to the engine, and the hydraulically driven cooling fan cools the engine cooling water flowing in the radiator It is good also as arrange | positioning.

  According to the above configuration, when the detected temperature of the engine cooling water becomes lower than the lower limit threshold temperature (for example, below freezing point) due to the temperature drop of the outside air, the rotational speed of the hydraulically driven cooling fan is set to the minimum rotational speed and hydraulically driven. By switching the cooling fan from forward rotation to reverse rotation, the cooling capacity of the hydraulically driven cooling fan can be reduced to the maximum, and further temperature drop of the engine cooling water can be prevented. As a result, it is possible to prevent the engine from being overcooled and reducing the efficiency of the engine.

  In the hydraulic drive cooling fan control system, the industrial vehicle has a load including the hydraulic drive cooling fan by a hydraulic pump that is operated by power of the engine and hydraulic oil that is discharged from the hydraulic pump as the cooling target. A hydraulic circuit that includes a hydraulic actuator to be driven; a hydraulic oil cooler that cools the hydraulic oil; and the hydraulic oil that flows through the hydraulic circuit is supplied to the hydraulic oil cooler. A hydraulic oil cooling mechanism that circulates the hydraulic oil so as to return the hydraulic oil cooled by the cooler to the hydraulic circuit, and the hydraulically driven cooling fan flows in the hydraulic oil cooler. It is good also as arrange | positioning so that it may cool.

  According to the above configuration, as with engine cooling water, when the detected temperature of the hydraulic oil becomes lower than the lower threshold temperature due to the temperature drop of the outside air, the cooling capacity of the hydraulically driven cooling fan is reduced to the maximum to operate. It is possible to prevent overcooling of the hydraulic oil via the oil cooler. Further, by preventing the hydraulic oil from being supercooled, it is possible to prevent the viscosity of the hydraulic oil from increasing, and thus to prevent the load resistance from increasing when the hydraulic circuit is activated.

In the hydraulically driven cooling fan control system, the industrial vehicle is configured to transmit the power of the engine using transmission oil as the cooling target, an oil cooler for transmission oil , and the transmission A transmission oil cooling mechanism for supplying the transmission oil from the transmission oil cooler to circulate the transmission oil so that the transmission oil cooled by the transmission oil oil cooler is returned to the transmission, and The hydraulically driven cooling fan may be arranged so as to cool the transmission oil flowing in the oil cooler for transmission oil.

  According to the above configuration, like the hydraulic oil, when the detected temperature of the transmission oil becomes lower than the lower limit threshold temperature due to the temperature drop of the outside air, the cooling capacity of the hydraulically driven cooling fan is reduced to the maximum, It is possible to prevent overcooling of the transmission oil through the oil cooler. In addition, by preventing overcooling of the transmission oil, it is possible to prevent an increase in the viscosity of the transmission oil, and thus an increase in load resistance when the transmission is operated.

In order to achieve the above object, the control method of the hydraulically driven cooling fan according to another aspect is capable of rotating in the forward and reverse rotation directions, takes the outside air, cools the object to be cooled by the outside air, and rotates. A hydraulically driven cooling fan that reduces the amount of air flow to the cooling target when the direction is reversely rotated than the normal rotation, and a rotation direction switching valve that switches the rotational direction of the hydraulically driven cooling fan between the normal rotation and the reverse rotation A control method for the hydraulically driven cooling fan in a cooling system comprising: a rotational speed control valve that controls the rotational speed of the hydraulically driven cooling fan; and a temperature detector that detects the temperature of the cooling target, Obtaining a detected temperature detected by a temperature detector; determining whether the detected temperature is less than a lower threshold temperature; and detecting the detected temperature as the lower threshold temperature. When it is determined that it is not less than, the rotational direction of the hydraulic drive cooling fan outputs the rotation direction command to the rotation direction switching valve so that the positive rotation, the rotation of the hydraulic drive cooling fan in response to the detected temperature When the rotational speed command for adjusting the rotational speed is output to the rotational speed control valve and it is determined that the detected temperature is lower than the lower limit threshold temperature, the rotational speed of the hydraulically driven cooling fan is the minimum rotational speed. A rotation direction command is output to the rotation direction switching valve so that the rotation direction of the hydraulically driven cooling fan is the reverse rotation in a state where the rotation number command is output to the rotation number control valve so that Is included.

  According to the method, it is possible to further reduce the cooling capacity of the hydraulically driven cooling fan and to prevent overcooling of the cooling target.

  In order to achieve the above object, an industrial vehicle according to still another embodiment includes any of the hydraulically driven cooling fan control systems described above.

  According to the present invention, it is possible to prevent overcooling of an object to be cooled by a hydraulically driven cooling fan.

FIG. 1 is a diagram illustrating a schematic configuration example of an industrial vehicle according to an embodiment. FIG. 2 is a block diagram showing an example of the overall configuration of the engine compartment of an industrial vehicle including the hydraulically driven cooling fan control system according to the embodiment. FIG. 3 is a diagram showing a detailed configuration example of the hydraulic circuit shown in FIG. FIG. 4 is a flowchart showing an operation example of the hydraulically driven cooling fan control system shown in FIG.

Hereinafter, preferred embodiments will be described with reference to the drawings. In the following description, the same or corresponding elements are denoted by the same reference symbols throughout the drawings, and redundant description thereof is omitted.
(Configuration example of industrial vehicle)
Industrial vehicles according to the present embodiment include all construction machines such as wheel loaders and tire rollers, industrial vehicles such as forklifts and aerial work platforms, and other vehicles used for industrial purposes.

  FIG. 1 is a diagram illustrating a schematic configuration example of a wheel loader as an example of an industrial vehicle according to the present embodiment. The wheel loader shown in FIG. 1 includes a vehicle body 602, and a pair of left and right wheels 603 and 604 are provided at a lower front portion and a lower rear portion of the vehicle body 602. A base end portion of an arm 605 is swingably attached to a front portion of the vehicle body 602, and a bucket 606 is swingably attached to a distal end portion of the arm 605. Hereinafter, for convenience of explanation, these arms 605 and buckets 606 may be collectively referred to as “work machines”.

  The actuator of the work machine includes a hoist cylinder 607 and a bucket cylinder 609. The hoist cylinder 607 is stretched between the vehicle body 602 and the arm 605, and the arm 605 swings around the left and right axes with respect to the vehicle body 602 as the hoist cylinder 607 expands and contracts. A lever 608 is fixed to the rear portion of the bucket 606, and a bucket cylinder 609 is bridged between the lever 608 and the arm 605. As the bucket cylinder 609 expands and contracts, the bucket 606 swings around the left and right axes with respect to the arm 605.

  An engine 100 that generates power is mounted on the rear portion of the vehicle body 602, and the engine 100 is connected to wheels 603 and 604 via a transmission 120, a propeller shaft 613, and axles 614 and 615. When the power generated by the engine 100 is transmitted to the wheels 603 and 604, a horizontal traction force is generated in the vehicle body 602 and the wheel loader can travel. The engine 100 may be composed of a single reciprocating internal combustion engine, or may be a so-called hybrid type in which an electric motor / generator is attached thereto. The transmission 120 can set a plurality of forward shift speeds and a plurality of reverse shift speeds.

  The output shaft of the engine 100 is connected to a hydraulic pump 5 that drives a hydraulically driven cooling fan 1 and the like, which will be described later, via a transmission 120. The hydraulic pump 5 is driven based on the power generated by the engine 100. It has become so.

In a cabin 617 provided at the upper part of the vehicle body 602, various operating devices 618 for an operator to perform a traveling operation and excavation work are provided. The operating device 618 includes, for example, a steering 619 for steering, an accelerator pedal 620 for operating the output of the engine 100, a shift lever 621 for shifting operation, an arm 605, and a work machine for operating swinging of the bucket 606. An operation lever 622 and the like are included.
(Example of the overall configuration of the engine compartment of an industrial vehicle)
FIG. 2 is a block diagram showing an example of the overall configuration of the engine compartment of an industrial vehicle including the hydraulically driven cooling fan control system according to the embodiment.

=== Engine cooling system ===
In the engine room 500 of the industrial vehicle shown in FIG. 2, as an engine cooling system, an engine 100, a radiator 200, an engine coolant WC as a cooling target that absorbs heat of the engine 100, and the engine 100 to the radiator 200. An engine cooling water cooling mechanism (101, 102, 105, etc.) that circulates the engine cooling water WC so as to supply the engine cooling water WC to the engine and return the engine cooling water WC cooled by the radiator 200 to the engine 100; A cooling fan 1 is provided. In the engine room 500 shown in FIG. 2, when the hydraulically driven cooling fan 1 rotates in the forward direction, the first outside air port 510 for sucking outside air into the room and the outside air sucked from the first outside air hole 510 are discharged. Two second outside air ports 520 for discharging outside the room are provided. The arrangement of the first outside air port 510 and the second outside air port 520 is not limited to that shown in FIG.

  The engine cooling water cooling mechanism (101, 102, 105, etc.) includes a water pipe 101, a water pipe 102, a water pipe 201, a pipe for engine cooling water WC arranged in the engine 100 (not shown), A water pump (not shown) and a thermostat 105 are included.

  The water pipe 101 is for supplying engine cooling water WC from the engine 100 to the radiator 200. The water pipe 102 is for returning the engine coolant WC that has been heat-exchanged with the outside air in the radiator 200 to the engine 100. The water pipe 201 connects the water pipe 101 and the water pipe 102 and allows the engine cooling water WC to flow through the radiator 200. Further, the water pipe 201 is disposed so as to be in contact with the outside air in the radiator 200 in order to cool the engine coolant WC flowing inside. The piping of the engine coolant WC disposed in the engine 100 is for absorbing heat in the engine 100 and is disposed in the engine 100. The water pump described above is for circulating the engine cooling water WC in the pipes (101, 102, 201, etc.) described above. The thermostat 105 is disposed in the vicinity of the inlet of the engine coolant WC of the engine 100.

  The thermostat 105 includes a temperature detector that detects the temperature of the engine coolant WC. When the temperature detected by the temperature detector of the thermostat 105 is equal to or higher than a set temperature (for example, 78 °), the thermostat 105 is “open”, and the engine cooling water WC passing through the water pipe 102 from the radiator 200 is supplied to the engine 100. Let it flow into. That is, when the thermostat 105 is open, the engine cooling water WC is supplied to the engine 100 (the piping of the engine cooling water WC disposed in the engine 100) and the radiator 200 (via the water piping 101 and the water piping 102). It will circulate between water piping 201).

  When the temperature detected by the temperature detector of the thermostat 105 is lower than a set temperature (for example, 78 °), the thermostat 105 is “closed” and flows into the engine 100 from the radiator 200 through the water pipe 102. Shut off engine coolant WC. When the thermostat 105 is closed, the engine coolant WC is disposed in the engine 100 (inside the engine 100) via a water pipe 101 and a bypass pipe (not shown) provided in parallel with the water pipe 102, respectively. Circulated between the engine cooling water WC pipe) and the radiator 200 (water pipe 201). These bypass pipes are configured such that the flow rate of the engine cooling water WC flowing through them is smaller than that of the water pipe 101 and the water pipe 102. As described above, even when the thermostat 105 is closed, a predetermined amount of engine coolant WC circulates between the engine 100 and the radiator 200 although the flow rate is smaller than when the thermostat 105 is open. Will be. 2 is disposed in the vicinity of the inlet of the engine cooling water WC of the engine 100, it may be disposed in the vicinity of the outlet of the engine cooling water WC of the engine 100.

  During forward rotation, the hydraulically driven cooling fan 1 takes in outside air from the first outside air port 510 to cool (heat exchange) the water pipe 201 of the engine cooling water WC in the radiator 200 with the outside air, and after heat exchange The outside air is disposed to be discharged toward two second outside air ports 520 provided at different positions from the first outside air port 510 through a cooling target to be described later in the engine chamber 500. . Specifically, the hydraulically driven cooling fan 1 is arranged with respect to the radiator 200 on the outside air exhaust side during the forward rotation of the hydraulically driven cooling fan 1 (downstream side in the outside air flow path during the forward rotation). It is covered with the fan shroud 202 and is disposed so as to face the radiator 200. In addition, the hydraulically driven cooling fan 1 may be disposed on the outside air intake side during the forward rotation of the hydraulically driven cooling fan 1 with respect to the radiator 200 (upstream side in the outside air flow path during the forward rotation). In this case, the fan shroud 202 is disposed on the outside air intake side during the forward rotation of the hydraulic drive cooling fan 1 together with the hydraulic drive cooling fan 1 (upstream side in the outside air flow path during the forward rotation).

  Further, the hydraulically driven cooling fan 1 is configured to be able to rotate in the rotation direction of “forward rotation” and “reverse rotation”. Then, when the hydraulically driven cooling fan 1 is rotating in the “forward rotation” direction, it takes in outside air from the first outside air port 510 and cools the engine cooling water WC (cooling target). In this case, the outside air taken in from the first outside air port 510 is discharged from the second outside air port 520. In addition, when the hydraulically driven cooling fan 1 rotates in the “reverse rotation” rotation direction, it takes in outside air from the second outside air port 520 and cools the engine cooling water WC (cooling target). In this case, the outside air taken in from the second outside air port 520 is discharged from the first outside air port 510. In addition, the hydraulically driven cooling fan 1 is set with blade inclinations so that the amount of air to be cooled is increased during normal rotation. In other words, the hydraulically driven cooling fan 1 has the highest cooling capacity when the rotation direction is normal. On the other hand, at the time of reverse rotation, since the inclination of the blades of the hydraulically driven cooling fan 1 does not correspond to the rotation direction, the air volume of the hydraulically driven cooling fan 1 is reduced as compared with the forward rotation. That is, when the rotational direction of the hydraulically driven fan 1 is reverse, the amount of air to the cooling target in the engine chamber 500 is smaller and the cooling capacity is lower than when the rotational direction is normal. Note that the air volume to the cooling target refers to the amount of air taken in by the rotation of the hydraulically driven cooling fan 1 and supplied to the cooling target.

=== Hydraulic oil and transmission oil cooling system ===
In engine room 500, transmission 120 connected to the output shaft of engine 100 is provided. The transmission 120 has a torque converter (not shown), and uses the transmission oil OM as a cooling target to drive the power of the engine 100 to various devices and devices (for example, the pump 5 of the hydraulic circuit 110 described later). To communicate.

  The engine chamber 500 further includes a hydraulic circuit 110 as a drive system for the hydraulically driven cooling fan 1. Although details will be described later, the hydraulic circuit 110 drives the hydraulic pump 5 (see FIG. 3) and the driven body including the hydraulically driven cooling fan 1 by the hydraulic oil OH as a cooling target discharged from the hydraulic pump 5. And an actuator (a cargo handling merging valve 50 and a fan control valve 60). The pump 5 is connected to the transmission 120, operates by the power of the engine 100 transmitted through the transmission, and discharges the hydraulic oil OH.

  Here, the viscosity of the hydraulic oil OH and the transmission oil OM decreases with an increase in temperature, for example, when the load is high. Then, the leakage amount of the hydraulic oil OH and the transmission oil OM increases, and the operating efficiency of the hydraulic circuit 110 and the transmission 120 is reduced. In addition, the lubricity deteriorates and causes seizure and wear. On the other hand, the viscosity of the hydraulic oil OH and the transmission oil OM increases as the temperature decreases. Then, the flow resistance of the hydraulic oil OH and the transmission oil OM increases, and the loss energy of the hydraulic circuit 110 and the transmission 120 increases. For this reason, it is necessary to control the hydraulic oil OH and the transmission oil OM to appropriate temperatures, and an oil cooler 210 for the hydraulic oil OH is provided in the engine chamber 500 as a cooling system for the hydraulic oil OH and the transmission oil OM. The oil cooler 220 for transmission oil OM and the operating oil OH flowing in the hydraulic circuit 110 are supplied to the oil cooler 210, and the operating oil OH is circulated so that the operating oil OH cooled by the oil cooler 210 is returned to the hydraulic circuit 110. The transmission oil OM is circulated so that the transmission oil OM is supplied from the hydraulic oil cooling mechanism (111, 211, 112) to the oil cooler 220 from the transmission 120 and the transmission oil OM cooled by the oil cooler 220 is returned to the transmission 120. Dora And scan transmission oil cooling mechanism (121,212,122), a hydraulic drive cooling fan 1, is provided.

  The hydraulic oil cooling mechanism (111, 211, 112) exchanges heat between the oil piping 111 for supplying the hydraulic oil OH (returned oil) from the hydraulic circuit 110 to the oil cooler 210 and the outside air in the oil cooler 210. An oil pipe 112 that returns the hydraulic oil OH to the hydraulic circuit 110, and an oil pipe 111 and an oil pipe 112 that are connected to flow the hydraulic oil OH into the oil cooler 210 and to be in contact with outside air in the oil cooler 210. Oil pipe 211 and the like.

  The transmission oil cooling mechanism (121, 212, 122) includes an oil pipe 121 that supplies transmission oil OM (returned oil) from the transmission 120 to the oil cooler 220, and a transmission in which heat exchange between the oil cooler 220 and outside air is performed. The oil pipe 122 for returning the oil OM to the transmission 120, and the oil pipe 121 and the oil pipe 122 are connected to flow the transmission oil OM through the oil cooler 220 and are arranged so as to be in contact with the outside air within the oil cooler 220. It is constituted by an oil pipe 212 and the like.

  The oil cooler 210 and the oil cooler 220 are arranged in a row in parallel with the radiator 200, and are arranged to face the hydraulically driven cooling fan 1. In other words, the hydraulically driven cooling fan 1 takes in outside air and cools the engine cooling water flowing in the radiator 200, the hydraulic oil OH flowing in the oil cooler 210, and the transmission oil OM flowing in the oil cooler 220. Are arranged as follows. Note that the positional relationship between the oil cooler 210 and the oil cooler 220 and the radiator 200 is as follows. The radiator 200 may be disposed on the upstream side in the air flow path.

=== Intercooler ===
FIG. 2 illustrates a configuration when the engine 100 is a supercharged engine. That is, in the engine chamber 500, a supercharger 131 that supplies compressed air AT to be cooled by the hydraulically driven cooling fan 1 toward the engine 100, and a compression that is supplied from the supercharger 131 toward the engine 100. An intercooler 130 for cooling the air AT is provided.

  The supercharger 131 is provided for the purpose of improving the fuel consumption and output of the engine 100 by precompressing the air fed into the engine 100. Examples of the air compression method of the supercharger 131 include a turbocharger type that compresses with exhaust gas and a supercharger type that compresses with the engine 100.

  The intercooler 130 is provided for the purpose of cooling the high-temperature and high-pressure compressed air AT before being supplied from the supercharger 131 to the engine 100 to further improve the fuel consumption and output of the engine 100. The intercooler 130 is further connected to the outside air intake side during the forward rotation of the hydraulically driven cooling fan 1 (upstream of the outside air flow path during the forward rotation) than the radiator 200, the oil cooler 210, and the oil cooler 220. Are arranged in parallel with each other, and are arranged so as to face the hydraulically driven cooling fan 1. The intercooler 130 is configured to cool the compressed air AT with the outside air taken in by the hydraulically driven cooling fan 1 before heat exchange is performed through the oil cooler 210, the oil cooler 220, and the radiator 200, respectively. ing. In other words, the hydraulically driven cooling fan 1 is arranged to take in outside air and cool the compressed air AT flowing in the intercooler 130.

  In oil cooler 210, oil cooler 220, radiator 200, and intercooler 130, the upper threshold temperature (described later) of the cooling target (hydraulic oil OH, transmission oil OM, engine coolant WC, compressed air AT) is usually not exceeded. In addition, each cooling object is cooled. This upper threshold temperature is, for example, 100 ° C. or lower for hydraulic oil OH, 120 ° C. or lower for transmission oil OM, 100 ° C. for engine cooling water WC, and the outside air temperature + 20 ° C. or lower for compressed air AT. Set to

=== Other configuration examples around the engine ===
FIG. 2 illustrates a configuration in the case where the engine 100 is further a diesel engine (Diesel Engine) with a DPF (Diesel Particulate Filter). That is, in the engine chamber 500, a DPF 140 that is a filter that captures particulate matter in the exhaust gas of the engine 100 is mounted near the exhaust port of the engine 100. When a predetermined amount of particulate matter is trapped in the DPF 140, the function of the DPF 140 is reduced. In order to prevent this deterioration in function, the DPF 140 uses the high-temperature exhaust gas of the engine 100 at a predetermined trigger to burn the captured particulate matter and regenerate the filter. Therefore, when the DPF 140 is regenerated, it is necessary to increase the exhaust gas temperature by applying a load to the engine 100, and the temperature of the engine coolant WC increases. Note that when the engine 100 is not a DPF-equipped diesel engine, the configuration described above may be omitted.

  2 is provided with an air conditioner for vehicle interior (150. As a configuration for cooling the air conditioner 150, the engine 100 is generally driven by the engine 100 to generate a refrigerant (gas phase). A compressor that compresses the refrigerant to increase the temperature and pressure, a condenser that cools the refrigerant (gas phase) that has been increased in temperature and pressure by the outside air to form a liquid phase, and a receiver that gas-liquid separates the refrigerant cooled by the condenser In addition, an evaporator that vaporizes the refrigerant (liquid phase) separated by the receiver and supplies the refrigerant to the compressor, a blower motor that blows air toward the evaporator and generates cold air, and the like are provided.

  The air conditioner condenser 151 shown in FIG. 2 is the condenser of the air conditioner 150 described above. The oil cooler 210, the oil cooler 220, and the radiator 200 are more than the outside air intake side during the forward rotation of the hydraulically driven cooling fan 1 (at the time of the forward rotation). And arranged in parallel with the intercooler 130 in a row. In other words, the outside air taken in by the hydraulically driven cooling fan 1 flows through the oil OH flowing in the oil cooler 210, the transmission oil OM flowing in the oil cooler 220, the engine coolant WC flowing in the radiator 200, and the intercooler 130. In parallel with the cooling of the compressed air AT, the refrigerant (gas phase) flowing in the air conditioner condenser 151 is cooled.

  In addition, as a configuration for heating the air conditioner 150, generally, a heat core that generates warm air using the engine coolant WC discharged from the engine 100 is provided. The engine cooling water WC that has undergone heat exchange in the heat core merges with the engine cooling water WC that has undergone heat exchange in the radiator 200, and returns to the engine 100. Thus, in order for the engine cooling water WC to be used for heating the air conditioner 150, it is necessary to raise the engine cooling water WC to a certain temperature.

=== Configuration example of hydraulic drive cooling fan control system ===
FIG. 2 shows a configuration example of a hydraulic drive cooling control system according to the embodiment.

  The hydraulic drive cooling control system shown in FIG. 2 detects a temperature detector 304 that detects the temperature T1 of the engine coolant WC, a temperature detector 305 that detects the temperature T2 of the hydraulic oil OH, and a temperature T3 of the transmission oil OM. A temperature detector 306 that detects the temperature T4 of the compressed air AT that flows through the intercooler 130, and a control device 300.

  For example, the temperature detector 304 is disposed on the water pipe 101 through which the engine cooling water WC flows from the engine 100 toward the radiator 200, but the pipe through which the engine cooling water WC in the engine 100 flows (not shown). It may be arranged on top.

  The temperature detector 305 may be disposed, for example, in an oil tank 2 (see FIG. 3) of hydraulic oil OH described later.

  The temperature detector 306 may be disposed on the oil pipe 122 through which the transmission oil OM flows from the oil cooler 220 toward the transmission 120, for example. Moreover, you may arrange | position in the pump suction line for transmissions.

  For example, the temperature detector 307 is disposed on a pipe through which the compressed air AT flows from the intercooler 130 toward the engine 100.

  The control device 300 includes a temperature T1 of the engine coolant WC detected by the temperature detector 304, a temperature T2 of the hydraulic oil OH detected by the temperature detector 305, and a temperature T3 of the transmission oil OM detected by the temperature detector 306. The rotational drive of the hydraulically driven cooling fan 1 is controlled based on the temperature T4 of the compressed air AT detected by the temperature detector 307.

  The example of the entire configuration of the engine compartment of the industrial vehicle including the hydraulically driven cooling fan control system shown in FIG. 2 has been described for each system. As described in part in the above-described embodiment, the arrangement of the devices such as the hydraulically driven cooling fan 1, the radiator 200, the oil coolers 210 and 220, the intercooler 130, and the air conditioner condenser 151 is shown in FIG. It is not limited to the embodiment shown. The arrangement of the devices may be changed as appropriate based on the state of the vehicle body 602 of the wheel loader, the wind flow in the engine room 500, and the size of each device.

(Configuration example of hydraulic circuit)
FIG. 3 is a diagram showing a detailed configuration example of the hydraulic circuit 110 shown in FIG. The hydraulic circuit 110 shown in FIG. 3 basically includes an oil tank 2, a hydraulic pump 5, an unloader mechanism 10, a brake control circuit 30, a cargo handling merging valve 50, a fan control valve 60, a high pressure selection mechanism 20, and a capacity adjustment mechanism 9. Consists of.

  Specifically, the hydraulic oil OH supplied from the hydraulic pump 5 is supplied to the input port 11 of the unloader mechanism 10 via the oil pipe 4. The hydraulic oil OH supplied to the input port 11 is supplied to the brake control circuit 30 via the throttle 12 and the first output port 13 and accumulated in a predetermined accumulator of the brake control circuit 30.

  The hydraulic pump 5 is driven via a transmission 120 driven by the engine 100. The hydraulic pump 5 includes a capacity adjustment mechanism 9 having a control valve 7 that is switched by a load sensing pressure (Pls), which will be described later, and a tilt angle adjustment unit 8 that is controlled by the control valve 7. The displacement angle of the hydraulic pump 5 is controlled by the capacity adjusting mechanism 9.

  When the circuit pressure (Pbreak) of the brake control circuit 30 falls below the set pressure, the unloader mechanism 10 preferentially supplies the hydraulic oil OH from the first output port 13 to the brake control circuit 30, and the circuit pressure ( A first valve 15 and a second valve 16 configured to supply hydraulic oil OH to the second output port 14 when Pbreak) is equal to or higher than a set pressure.

  As an operation of the unloader mechanism 10, first, when the circuit pressure (Pbreak) of the brake control circuit 30 led to the first valve 15 through the pilot oil pipe 36 is equal to or lower than the set pressure, the unloader mechanism 10 is supplied to the input port 11. The hydraulic oil OH is supplied to the brake control circuit 30 via the throttle 12 and the first output port 13.

  Next, when the hydraulic oil OH is accumulated in the brake control circuit 30 and the circuit pressure (Pbreak) reaches a set pressure, the first valve 15 and the drain pipe 19 are electrically connected, so the first valve The primary pressure at 15 drops to the oil tank pressure. Accordingly, the hydraulic oil OH supplied to the input port 11 is supplied to the second output port 14 via the second valve 16, so that the hydraulic oil OH is not supplied from the unloader mechanism 10 to the brake control circuit 30. Cut out.

  Next, when the energy of the hydraulic oil OH accumulated in the brake control circuit 30 is consumed, the circuit pressure (Pbreak) of the brake control circuit 30 is lower than the set pressure of the unloader mechanism 10. At this time, a cut-in state in which the hydraulic oil OH is supplied from the unloader mechanism 10 to the brake control circuit 30 is set. As described above, when the hydraulic oil OH discharged from the hydraulic pump 5 preferentially flows to the brake control circuit 30 side, the discharge amount of the hydraulic pump 5 increases as will be described later, and the circuit pressure (Pbreak) of the brake control circuit 30 increases. Rises again.

  The cargo handling merge valve 50 is provided with a switching valve 51. The switching valve 51 determines the supply destination of the hydraulic oil OH discharged from the second output port 14 of the unloader mechanism 10 by the electromagnetic switching valve 56 provided in the branch pipe 55 branched from the secondary side of the variable throttle 52. The operation is switched to the fan control valve 60 (the electromagnetic switching valve 56 is OFF) or the cargo handling (not shown) via the cargo handling merging pipe 54.

  The fan control valve 60 is provided with an electromagnetic control valve 61. The electromagnetic control valve 61 switches the direction in which the hydraulic oil OH flows to the hydraulically driven cooling fan 1 in order to control the rotation direction of the hydraulically driven cooling fan 1. Further, the fan control valve 60 is provided with an electromagnetic inverse proportional valve 64 that controls the rotational speed of the hydraulically driven cooling fan 1.

  In the hydraulic circuit 110, the circuit pressure (Pun) of the unloader mechanism 10 is guided to the high pressure selection mechanism 20 via the pilot pipe 21. Further, the cargo handling merge pressure (Pload) from the cargo handling merge valve 50 is guided to the high pressure selection mechanism 20 via the pilot pipe 57. Further, the fan rotation speed control pressure (Pfan) of the fan control valve 60 is guided to the high pressure selection mechanism 20 via the pilot pipe 63.

  The high pressure selection mechanism 20 loads the highest pressure among the circuit pressure (Pun) of the unloader mechanism 10, the cargo handling merging pressure (Pload) of the cargo handling merging valve 50, and the fan rotation speed control pressure (Pfan) of the fan control valve 60. Select as sensing pressure (Pls). The tilt angle of the hydraulic pump 5 is controlled by the tilt angle adjusting unit 8 so that the hydraulic oil OH having a flow rate corresponding to the load sensing pressure (Pls) is discharged.

  For example, as the circuit pressure (Pbreak) of the brake control circuit 30 decreases, the unloader mechanism 10 switches from the cut-out state to the cut-in state, so that the circuit pressure (Pun) of the unloader mechanism 10 rises again and the load sensing pressure is increased. (Pls) is selected. As a result, the tilt angle of the hydraulic pump 5 is controlled to increase, and the discharge flow rate from the hydraulic pump 5 increases. Then, until the circuit pressure (Pbreak) of the brake control circuit 30 reaches the set pressure, a flow rate corresponding to the load sensing pressure (Pls) is discharged from the hydraulic pump 5, and the required amount of hydraulic oil OH is supplied to the brake control circuit 30. Accumulate quickly.

  After that, when the hydraulic oil OH at the set pressure is accumulated in the brake control circuit 30, the hydraulic oil OH is discharged from the second output port 14 via the second valve 16, so that the state of the unloader mechanism 10 is cut. Switch from in state to cut out state. At this time, the hydraulic oil OH discharged from the second output port 14 is supplied to the cargo handling merging valve 50 and the fan control valve 60. In the high pressure selection mechanism 20, the highest pressure among the circuit pressure (Pun) of the unloader mechanism 10, the cargo handling merging pressure (Pload) of the cargo handling merging valve 50, and the fan rotation speed control pressure (Pfan) of the fan control valve 60. Is selected as the load sensing pressure (Pls). As a result, the tilt angle adjusting unit 8 of the capacity adjusting mechanism 9 is controlled so that the flow rate discharged from the hydraulic pump 5 becomes the minimum necessary flow rate for the cargo handling merging valve 50 and the fan control valve 60.

  The hydraulic pump 5 is directly connected to the engine 100 via the transmission 120 and constantly discharges hydraulic pressure, and the hydraulic pump 5 based on the load sensing pressure (Pls) using the hydraulic pressure constantly discharged from the hydraulic pump 5. The tilt angle control is performed. For this reason, the hydraulically driven cooling fan 1 always operates.

(Operation example of hydraulic drive cooling fan control system)
FIG. 4 is a flowchart showing an operation example of the hydraulically driven cooling fan control system shown in FIG.

  First, when the control device 300 detects that the engine 100 has been started (step S400), the temperature T1 of the engine coolant WC detected by the temperature detector 304 and the hydraulic oil OH detected by the temperature detector 305 are detected. The temperature T2, the temperature T3 of the transmission oil OM detected by the temperature detector 306, and the temperature T4 of the compressed air AT detected by the temperature detector 307 are acquired (step S401).

  Next, the controller 300 sets the upper limit threshold temperature corresponding to at least one of the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT. It is determined whether or not this is the case (step S402). When none of the temperatures T1 to T4 is equal to or higher than the upper limit threshold (step S402: NO), the process proceeds to step S403. The upper threshold temperature is a predetermined temperature determined by the type of cooling object (engine cooling water WC, hydraulic oil OH, transmission OM, compressed air AT) and usage conditions, and the temperature of the cooling object is equal to or higher than this temperature. In this case, it is determined that the object to be cooled is in an overheated state.

  In step S403, the control device 300 lowers the threshold value corresponding to at least one of the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT. It is determined whether or not the temperature is lower. If all of the temperatures T1 to T4 are equal to or higher than the lower threshold, the determination is false (step S403: NO), and the process proceeds to step S404. The lower limit threshold temperature is a predetermined temperature determined by the type and usage of the cooling target (engine cooling water WC, hydraulic oil OH, transmission OM, compressed air AT), and the cooling target temperature is lower than this temperature. In this case, it is determined that the object to be cooled is in a supercooled state.

  In step S404, the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT are lower than the corresponding upper threshold temperature and correspond to each. Above the lower threshold temperature. Therefore, the controller 300 determines the rotational speed of the hydraulically driven cooling fan 1 in accordance with the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT. A rotational speed command is output to the fan control valve 60 (electromagnetic inverse proportional valve 64) of the hydraulic circuit 110 so that the highest rotational speed NR is obtained among the rotational speeds (step S404). Note that the control for adjusting the rotational speed in accordance with the temperature is a control in which the rotational speed is increased to increase the air volume if the temperature is high, and conversely, if the temperature is low, the rotational speed is decreased to reduce the air volume. Say. Here, this control is referred to as “first control”. Note that the rotation direction of the hydraulically driven cooling fan 1 when performing this control is forward rotation. Then, the process returns to step S401.

  At least one of the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT due to an overload of the engine 100, the hydraulic circuit 110, etc. It may be true whether the temperature is equal to or higher than the corresponding upper threshold temperature (step S402: YES). In this case, the control device 300 maximizes the cooling capacity of the hydraulically driven cooling fan 1 to cool the engine cooling water WC, the hydraulic oil OH, the transmission oil OM, and the compressed air AT in common. Specifically, the control device 300 outputs a rotational speed command to the fan control valve 60 (electromagnetic inverse proportional valve 64) of the hydraulic circuit 110 so that the rotational speed of the hydraulically driven cooling fan 1 becomes the maximum rotational speed NMAX. (Step S405). Further, the control device 300 outputs a rotation direction command to the fan control valve 60 (electromagnetic control valve 61) of the hydraulic circuit 110 so that the rotation direction of the hydraulically driven cooling fan 1 is forward rotation (step S405). Then, the process returns to step S401.

  Further, due to the cause of the temperature of the outside air being below freezing point, for example, at least one of the temperature T1 of the engine cooling water WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT is The determination as to whether or not the temperature is lower than the corresponding lower threshold temperature may be true (step S403: YES). In this case, the control device 300 minimizes the cooling capacity of the hydraulically driven cooling fan 1 and cools the engine cooling water WC, the hydraulic oil OH, the transmission oil OM, and the compressed air AT in common. Specifically, the control device 300 outputs a rotational speed command to the fan control valve 60 (electromagnetic inverse proportional valve 64) of the hydraulic circuit 110 so that the rotational speed of the hydraulically driven cooling fan 1 becomes the minimum rotational speed NMIN. (Step S406). Furthermore, the control device 300 outputs a rotation direction command to the fan control valve 60 (electromagnetic control valve 61) of the hydraulic circuit 110 so that the rotation direction of the hydraulically driven cooling fan 1 is reversed (step S406). Here, this control is referred to as “second control”. As described above, the reverse rotation means that the rotation direction of the hydraulically driven cooling fan 1 is reversed from that in the normal rotation, and the direction of the outside air passage is reversed from that in the normal rotation, and the object to be cooled (engine cooling water WC). , Hydraulic oil OH, transmission oil OM, compressed air AT) is in a direction in which the air volume is smaller than that during forward rotation. Then, the process returns to step S401.

  Here, at least one of the temperatures T1, T2, T3, and T4 is lower than the corresponding lower threshold temperature (step S403: YES), and at least one of the temperatures T1, T2, T3, and T4 is selected. Are equal to or higher than the corresponding upper threshold temperatures (step S402: YES), the determination in step S402 precedes the determination in step S403, and therefore the control in step S405 is executed in preference to the control in step S406. The

  In the above description, the control device 300 acquires the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT. Not limited. For example, the control device 300 may further acquire the pressure of the refrigerant (gas phase) flowing through the air conditioner condenser 151 and execute the above-described control (steps S400 to S406). Further, the control device 300 acquires only one of the temperature T1 of the engine coolant WC, the temperature T2 of the hydraulic oil OH, the temperature T3 of the transmission oil OM, and the temperature T4 of the compressed air AT, and Control (steps S400 to S406) may be executed. For example, the above-described control (steps S400 to S406) may be executed only by the temperature T1 of the engine coolant WC that cools the main engine 100 among the heat sources in the engine room 500.

(Function and effect)
As described above, when all the temperatures (all T1 to T4) detected by the temperature detectors (304 to 307) are equal to or higher than the lower threshold temperature, the hydraulic drive cooling is performed according to the temperature detected by the temperature detector. When the rotation speed of the fan 1 is set and at least one of the temperatures detected by the temperature detector is lower than the lower threshold temperature corresponding to each cooling target, the rotation of the hydraulically driven cooling fan 1 The number is set to the minimum number of rotations NMIN, and the rotation direction of the hydraulically driven cooling fan 1 is reversed.
When a hydraulic circuit that controls the rotational speed of the hydraulically driven cooling fan 1 based on the load sensing pressure (Pls) as shown in FIG. 3 is used, the pressure of the hydraulic pump 5 is set to the load sensing pressure (Pls). ) The cooling capacity of the hydraulically driven cooling fan 1 cannot be reduced sufficiently because it cannot be lowered. For this reason, there is a risk that overcooling of the objects to be cooled (engine cooling water WC, hydraulic oil OH, transmission oil OM, compressed air AT, etc.) may occur. On the other hand, in the present embodiment, when the detected temperature to be cooled is lower than the lower limit threshold temperature (for example, below freezing point) due to the temperature drop of the outside air, the rotational speed of the hydraulically driven cooling fan 1 is set to the minimum rotational speed. In addition, by making the rotation direction of the hydraulically driven cooling fan reverse, the air volume to the cooling target is reduced compared to the normal rotation. As a result, the cooling capacity of the hydraulically driven cooling fan 1 can be further reduced, and overcooling of the cooling target can be prevented.

  Further, when at least one temperature among a plurality of temperatures (T1 to T4, etc.) detected in each of the plurality of temperature detectors (304 to 307, etc.) is lower than a corresponding lower threshold temperature, a hydraulically driven cooling fan The rotational speed of 1 is set to the minimum rotational speed, and the rotational direction of the hydraulically driven cooling fan 1 is reversed. Thereby, the overcooling of all the several cooling object can be prevented.

  In addition, while setting the rotational speed of the hydraulically driven cooling fan 1 to the minimum rotational speed and performing control to reverse the rotational direction of the hydraulically driven cooling fan 1, a plurality of temperature detectors (304 to 307, etc.) are performed. ) When at least one temperature among the plurality of temperatures detected in each becomes higher than the upper threshold temperature, this control is released. Accordingly, when the cooling capacity of the hydraulically driven cooling fan 1 is reduced, if the temperature of at least one cooling target is higher than the upper threshold temperature, the rotational speed of the hydraulically driven cooling fan 1 is reduced to the minimum rotation. In addition to releasing the control to reverse the rotation direction of the hydraulically driven cooling fan 1, the cooling of the cooling target by the hydraulically driven cooling fan 1 can be resumed.

  Further, the control (first control and second control) of the hydraulically driven cooling fan 1 can be switched by manual operation regardless of the temperature detected by the temperature detector. As a result, the operator can switch the control of the hydraulically driven cooling fan 1 to manual operation based on the temperature of the outside air and the detected temperature of the fluid.

  Further, when the detected temperature T1 of the engine coolant WC is lower than the lower limit threshold temperature (for example, below freezing point) due to the low temperature of the outside air, the rotational speed of the hydraulically driven cooling fan 1 is set to the minimum rotational speed NMIN. The rotational direction of the hydraulically driven cooling fan 1 is reverse. Thereby, the cooling capacity of the hydraulically driven cooling fan 1 can be reduced to the maximum, and further temperature drop of the engine cooling water can be prevented. As a result, it is possible to prevent engine 100 from being overcooled and reducing the efficiency of engine 100. Further, as a secondary effect, it is possible to solve the problem that the DPF regeneration cannot be performed unless the temperature T1 of the engine coolant WC is higher than a predetermined temperature.

  Further, since the air conditioner 150 uses the heat of the engine coolant WC during heating, there is a problem that the heating function is lowered when the temperature T1 of the engine coolant WC is low. On the other hand, by using the hydraulic drive cooling fan control system (control method of the hydraulic drive cooling fan) according to the embodiment, the engine cooling water WC can be prevented from being overcooled and the heating function of the air conditioner 150 is prevented from being lowered. Can do.

  Similarly to the engine cooling water WC, when the detected temperature T2 of the hydraulic oil OH is lower than the lower limit threshold temperature due to a low outside air temperature, the cooling capacity of the hydraulically driven cooling fan 1 is reduced to the maximum. The overcooling of the hydraulic oil OH through the oil cooler 210 can be prevented. Further, by preventing the supercooling of the hydraulic oil OH, it is possible to prevent an increase in the viscosity of the hydraulic oil OH due to a temperature drop, and thus an increase in load resistance when the hydraulic circuit 110 is activated. Further, when the hydraulic pump 5 is configured to control the tilt angle based on the load sensing pressure (Pls), the hydraulic pump 5 cannot be stopped and it is difficult to stop the rotation of the hydraulically driven cooling fan 1. However, the cooling capacity of the hydraulically driven cooling fan 1 can be reduced only by control by the control device 300 without changing the basic hydraulic circuit 110 or adding equipment.

  Similarly to the hydraulic oil OH, when the detected temperature T3 of the transmission oil OM is lower than the lower threshold temperature due to the low temperature of the outside air, the cooling capacity of the hydraulically driven cooling fan 1 is reduced to the maximum, Overcooling of the transmission oil OM via the oil cooler 210 can be prevented.

  Further, the fan hydraulic motor has a minimum number of rotations, and cannot be reliably rotated at a lower number of rotations. Therefore, even if it is rotated at the minimum number of revolutions, there is a possibility that overcooling of the cooling target is caused. On the other hand, by using the hydraulically driven cooling fan control system (control method of the hydraulically driven cooling fan) according to the embodiment, the cooling capacity of the hydraulically driven cooling fan 1 is further reduced to prevent overcooling of the cooling target. can do.

  From the foregoing description, many modifications and other embodiments of the present invention are obvious to one skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure and / or function may be substantially changed without departing from the spirit of the invention.

  The present invention is useful for systems with hydraulically driven cooling fans, particularly industrial vehicles.

DESCRIPTION OF SYMBOLS 1 ... Hydraulic drive cooling fan 2 ... Oil tank 3, 4 ... Oil piping 5 ... Hydraulic pump 7 ... Control valve 8 ... Tilt angle adjustment part 9 ... Capacity adjustment mechanism DESCRIPTION OF SYMBOLS 10 ... Unloader mechanism 11 ... Input port 12 ... Restriction 13 ... 1st output port 14 ... 2nd output port 15 ... 1st valve 16 ... 2nd Valve 19 ... Drain piping 20 ... High pressure selection mechanism 21 ... Pilot piping (Pilot pressure Pun)
22 ... Oil piping 23 ... Pilot piping (Pilot pressure Pls)
30 ... Brake control circuit 36 ... Pilot piping (Pilot pressure Pbreak)
50 ... Cargo merging valve 51 ... Switching valve 52 ... Variable throttle 53 ... Check valve 54 ... Cargo handling merging pipe 55 ... Branch pipe 56 ... Electromagnetic switching valve 57 ... Pilot Piping (Pilot pressure Pload)
60 ... Fan control valve 61 ... Electromagnetic control valve 63 ... Pilot piping (Pilot pressure Pfan)
64 ... Electromagnetic inverse proportional valve 100 ... Engine 101, 102 ... Water piping 105 ... Thermostat 110 ... Hydraulic circuit 111, 112 ... Oil piping 120 ... Transmission 121, 122 ... Oil pipe 130 ... intercooler 131 ... supercharger 150 ... air conditioner 151 ... air conditioner condenser 200 ... radiator 201 ... water pipe 202 ... fan shroud 210 ... oil cooler ( For hydraulic oil)
211, 212 ... Oil piping 220 ... Oil cooler (for transmission oil)
300 ... Control device 304 ... Temperature detector (for engine coolant)
305 ... Temperature detector (for hydraulic oil)
306 ... Temperature detector (for transmission oil)
307 ... Temperature detector (for compressed air)
500 ... Engine chamber 510 ... First outside air port 520 ... Second outside air port WC ... Engine cooling water OH ... Hydraulic oil OM ... Transmission oil AT ... Compressed air NMAX ... Maximum number of revolutions NMIN ... Minimum number of revolutions T1 ... Engine coolant temperature T2 ... Working oil temperature T3 ... Transmission oil temperature T4 ... Compressed air temperature

Claims (9)

Hydraulic pressure that can be rotated in the forward and reverse rotation directions, takes in the outside air, cools the object to be cooled by the outside air, and reduces the air volume to the object to be cooled when the rotation direction is the reverse rotation than that during the normal rotation. A driving cooling fan,
A rotation direction switching valve that switches the rotation direction of the hydraulically driven cooling fan between the forward rotation and the reverse rotation;
A rotational speed control valve for controlling the rotational speed of the hydraulically driven cooling fan;
A temperature detector for detecting the temperature of the cooling object;
When the temperature detected by the temperature detector is higher than a lower threshold temperature, a rotation direction command is output to the rotation direction switching valve so that the rotation direction of the hydraulically driven cooling fan is the normal rotation, A first control for outputting a rotational speed command for adjusting the rotational speed of the hydraulically driven cooling fan to the rotational speed control valve in accordance with the temperature detected by the temperature detector;
When the temperature detected by the temperature detector is lower than the lower limit threshold temperature, a rotation speed command is output to the rotation speed control valve so that the rotation speed of the hydraulically driven cooling fan becomes the minimum rotation speed. A control device that performs a second control that outputs a rotation direction command to the rotation direction switching valve so that the rotation direction of the hydraulically driven cooling fan is the reverse rotation;
With hydraulic drive cooling fan control system. While having a plurality of cooling objects as the cooling object, and having a plurality of temperature detectors for each of the cooling objects as the temperature detector,
2. The control device according to claim 1, wherein the control device performs the second control when at least one temperature among a plurality of temperatures detected by each of the temperature detectors is lower than a corresponding lower threshold temperature. Hydraulic drive cooling fan control system.   When at least one temperature among the plurality of temperatures detected by each of the temperature detectors is higher than the upper limit threshold temperature during the second control, the control device performs the second control. The hydraulically driven cooling fan control system according to claim 2, wherein the control is switched from control to the first control.   2. A switching unit that manually switches between the first control and the second control in the control device for the hydraulically driven cooling fan, regardless of the temperature detected by the temperature detector. The hydraulic drive cooling fan control system according to 2. The hydraulically driven cooling fan control system includes an engine, a radiator, engine cooling water as the cooling target, and the engine cooling water cooled by the radiator by supplying the engine cooling water from the engine to the radiator. And an engine cooling water cooling mechanism that circulates the engine cooling water so that the engine cooling water is returned to the engine.
5. The hydraulic drive cooling fan control system according to claim 1, wherein the hydraulic drive cooling fan is disposed so as to cool the engine cooling water flowing through the radiator. 6. The industrial vehicle includes a hydraulic pump that is operated by power of the engine, and a hydraulic actuator that drives a load including the hydraulically driven cooling fan by operating oil discharged from the hydraulic pump as the cooling target. A circuit, a hydraulic oil cooler for cooling the hydraulic oil, and the hydraulic oil flowing in the hydraulic circuit is supplied to the hydraulic oil cooler to cool the hydraulic oil cooled by the hydraulic oil cooler. A hydraulic oil cooling mechanism that circulates the hydraulic oil to return to the hydraulic circuit, and
The hydraulic drive cooling fan control system according to claim 5, wherein the hydraulic drive cooling fan is arranged to cool the hydraulic oil flowing in the hydraulic oil cooler. The industrial vehicle includes a transmission configured to transmit the power of the engine using transmission oil as the object to be cooled, a transmission oil oil cooler, and the transmission to the transmission oil oil cooler. A transmission oil cooling mechanism for supplying the transmission oil and circulating the transmission oil so that the transmission oil cooled by the transmission oil oil cooler is returned to the transmission; and
The hydraulic drive cooling fan control system according to claim 6, wherein the hydraulic drive cooling fan is arranged to cool the transmission oil flowing through the oil cooler for transmission oil. Hydraulic drive that can rotate in the forward and reverse rotation directions, takes outside air, cools the object to be cooled by the outside air, and reduces the air volume to the object to be cooled when the rotation direction is reverse. A cooling fan, a rotation direction switching valve that switches the rotation direction of the hydraulically driven cooling fan between the forward rotation and the reverse rotation, a rotation speed control valve that controls the rotation speed of the hydraulically driven cooling fan, and the cooling target A method for controlling the hydraulically driven cooling fan in a cooling system comprising a temperature detector for detecting temperature,
Obtaining a detected temperature detected by the temperature detector;
Determining whether the detected temperature is less than a lower threshold temperature;
When it is determined that the detected temperature is not less than the lower threshold temperature, a rotation direction command is output to the rotation direction switching valve so that the rotation direction of the hydraulically driven cooling fan becomes the normal rotation, and the detected temperature is changed according to the detected temperature. Outputting a rotational speed command for adjusting the rotational speed of the hydraulically driven cooling fan to the rotational speed control valve;
When it is determined that the detected temperature is lower than the lower limit threshold temperature, the hydraulic pressure is output in a state in which a rotational speed command is output to the rotational speed control valve so that the rotational speed of the hydraulically driven cooling fan becomes a minimum rotational speed. Outputting a rotation direction command to the rotation direction switching valve so that the rotation direction of the driving cooling fan is the reverse rotation;
Control method for hydraulically driven cooling fan including   An industrial vehicle comprising the hydraulically driven cooling fan control system according to any one of claims 1 to 7.

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