JP2000161233A - Hydraulically driven cooling fan device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulically driven cooling fan device which can reduce the number of hydraulic pumps, can reduce the horsepower consumption, can reduce the occupying area, and can reduce the cost. SOLUTION: This hydraulic driven cooling fan device of a construction machine is provided with plural hydraulic pumps having at least the first hydraulic pump and the second hydraulic pump to operate a working machine, a steering, a pilot type operation valve, a change gear, and the like, and a hydraulic motor for driving the cooling fan of an engine radiator. That cooling fan device is also provided with a joining circuit 32 to join the branch circuit 20 branched from the discharge circuit of the first hydraulic pump 10, and the discharge circuit 31 of the second hydraulic pump 30, and to feed the pressure oil to a hydraulic motor 4 for driving the cooling fan 3; and a pump capacity control means to control the discharge amount of the first hydraulic pump 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a hydraulically driven cooling fan device for construction equipment.

[0002]

2. Description of the Related Art Conventionally, a hydraulically driven cooling fan of a construction machine is driven by a dedicated hydraulic pump, and its discharge amount is controlled by a thermo valve which operates according to the temperature of cooling water. FIG. 6 is a circuit diagram showing an example of a conventional drive device for a hydraulically driven cooling fan. In FIG. 6, a cooling fan 3 driven by a hydraulic motor 4 is disposed in front of a radiator 2 for cooling the cooling water of the engine 1. The variable displacement fan drive pump 50 for driving the hydraulic motor 4 is driven by the engine 1, and its discharge circuit 51 is connected to the hydraulic motor 4, and the drain circuit 52 of the hydraulic motor 4 is connected to the oil tank 5. The cooling water passage 6 of the radiator 2 is provided with a thermo valve 7. The thermo valve 7 closes when the cooling water temperature of the radiator 2 is high, and opens according to the temperature when the water temperature decreases. The variable displacement fan drive pump 50 is a first cylinder 5 for swash plate control.
3 and a second cylinder 54. First cylinder 5
The bottom side of the pump 3 and the discharge circuit 51 of the fan drive pump 50 are connected by a circuit 55, and the bottom side of the second cylinder 54 and the discharge circuit 51 of the fan drive pump 50 are connected by a circuit 56 to the cutoff valve 12 or the load. It is connected via a sensing valve 13. When the first cylinder 53 extends, the discharge amount of the fan drive pump 50 becomes MAX.
In the MIN direction when the second cylinder 54 extends. The load sensing valve 13 has a drain position A and a press position B. Load sensing valve 1
The pilot operation unit 3 on the drain position A side and one side of the thermo valve 7 are connected by a pilot circuit 57, and the other side of the thermo valve 7 is connected to the oil tank 5 via a drain circuit 8. Also, load sensing valve 1
The third pilot operation unit on the pressure position B side is connected to the circuit 56. The circuit 56 and the pilot circuit 57 are connected by a circuit 58, and the circuit 58 is provided with a diaphragm 59.

Next, the operation will be described. The cutoff valve 12 serves as a relief valve of the fan drive pump 50, and a detailed description thereof will be omitted. When the cooling water temperature of the radiator 2 is high, the thermo valve 7 is closed, and the oil pressure of the pilot circuit 57 becomes equal to the pressure of the discharge circuit 51. Therefore, the load sensing valve 13 is at the position A, and the bottom side of the second cylinder 54 is connected to the oil tank 5. The first cylinder 53 extends to the bottom side by receiving the pressure of the discharge circuit 51, the fan drive pump 50 discharges a large amount of oil, drives the hydraulic motor 4 at high speed, rotates the cooling fan 3 at high speed, and controls the radiator 2. Increase cooling capacity. When the cooling water temperature of the radiator 2 becomes low, the thermo valve 7 opens, and the pilot circuit 57 is drained to the oil tank 5 via the drain circuit 8. Therefore, the pressure of the pilot circuit 57 decreases, and the load sensing valve 13 switches to the position B. for that reason,
The hydraulic pressure of the discharge circuit 51 of the fan drive pump 50 is applied to the bottom side of the second cylinder 54, and the second cylinder 54 extends to reduce the discharge amount of the fan drive pump 50. As a result, the rotation speed of the hydraulic motor 4 decreases, the cooling fan 3 rotates at a low speed, the air volume decreases, the cooling capacity of the radiator 2 decreases, and the cooling water temperature increases.

The above situation will be described with reference to a graph shown in FIG. FIG. 7 is a graph showing the relationship between the engine speed and the discharge amount of the cooling fan drive pump. The horizontal axis of the graph is the engine speed, and the vertical axis is the discharge amount of the hydraulic pump (fan drive pump 50 in this example). It is. The discharge amount of the hydraulic pump linearly increases in proportion to the rotation between the engine low idle and the high idle as shown by a line E in the figure. However, as described above, when the radiator water temperature is low, the MIN flow rate is as shown by the solid line e, and when the radiator water temperature is high, the MAX flow rate is as shown by the solid line f. That is, the discharge amount of the hydraulic pump is controlled by the thermo valve 7 within a range surrounded by a solid line. As described above, the cooling water temperature of the engine 1 is always kept at an almost optimum temperature, the engine performance is kept good, and the horsepower consumed by the cooling fan is minimized.

[0005]

However, in construction machines, work machines, steering, pilot operated valves,
In addition to having a plurality of hydraulic pumps for operating a transmission and the like, the above configuration uses a hydraulic pump exclusively for driving a cooling fan, so that the number of hydraulic pumps increases as a whole vehicle, and However, there is a problem that the method becomes complicated, a lot of space is required, and the cost increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a hydraulically driven cooling fan device which requires a small number of hydraulic pumps, requires a small space, and is inexpensive.

[0007]

In order to achieve the above object, a first invention of a hydraulically driven cooling fan device according to the present invention comprises a working machine, a steering wheel, a pilot operated valve, a transmission and the like. A plurality of hydraulic pumps having at least a first hydraulic pump and a second hydraulic pump for operating
In a hydraulic drive cooling fan device of construction machinery comprising a hydraulic motor for driving a cooling fan of an engine radiator,
A branch circuit branching from the discharge circuit of the first hydraulic pump and a discharge circuit of the second hydraulic pump, and a merge circuit for supplying pressure oil to a hydraulic motor for driving the cooling fan; and a first circuit based on the water temperature of the radiator. And a pump displacement control means for controlling the discharge amount of the hydraulic pump.

In the above configuration, since the existing first hydraulic pump and second hydraulic pump are joined to drive the hydraulic motor for driving the cooling fan, it is not necessary to provide a hydraulic pump dedicated to the cooling fan. Therefore, the number of hydraulic pumps is small, the structure is simple, the area is small, and the cost is low. In addition, since the discharge amount of the first hydraulic pump is controlled by the water temperature of the radiator, the first hydraulic pump is controlled.
The oil amount of the hydraulic pump can be effectively used, and the horsepower consumed for driving the cooling fan can be reduced, which is economical.

A second invention provides a plurality of hydraulic pumps having at least a first hydraulic pump and a second hydraulic pump for operating a work machine, a steering wheel, a pilot operated valve, a transmission, and the like, and a driving fan for driving a cooling fan of an engine radiator. A hydraulic motor-driven cooling fan device for a construction machine including a hydraulic motor, wherein a branch circuit branched from a discharge circuit of the first hydraulic pump;
And a discharge circuit of the second hydraulic pump, and a discharge circuit for supplying pressure oil to the hydraulic motor for driving the cooling fan, and controlling discharge amounts of the first hydraulic pump and the second hydraulic pump based on the water temperature of the radiator. And a pump displacement control means.

In the above configuration, since the existing first hydraulic pump and second hydraulic pump are joined to drive the hydraulic motor for driving the cooling fan, it is not necessary to provide a hydraulic pump dedicated to the cooling fan. Therefore, the number of hydraulic pumps is small, the structure is simple, the area is small, and the cost is low. In addition, since the discharge amounts of the first hydraulic pump and the second hydraulic pump are controlled based on the water temperature of the radiator, the oil amounts of the first hydraulic pump and the second hydraulic pump are effectively used, and the consumption for driving the cooling fan is reduced. Horsepower can be reduced and it is economical.

According to a third aspect based on the configuration of the first aspect, the first hydraulic pump is a variable displacement steering pump, and the discharge circuit joining the joining circuit is a steering circuit from the steering pump. And

According to the above configuration, since the first hydraulic pump is an existing variable displacement type steering pump, a steering pump that does not use the entire amount at all times can be effectively used, and the loss due to the displacement change is small. Also, the use of a steering circuit is economical.

According to a fourth aspect based on the configuration of the first or second aspect, the first hydraulic pump is a variable displacement steering pump, the second hydraulic pump is a pilot pump,
The discharge circuit merging with the merging circuit includes a steering circuit from a steering pump and a pilot circuit from a pilot pump.

According to the above configuration, since the first hydraulic pump is an existing variable displacement steering pump and the second hydraulic pump is also an existing pilot pump, the capacity of each hydraulic pump can be effectively used. It is possible, and the structure is simple and economical because it utilizes a steering circuit and a pilot circuit.

A fifth invention is based on any one of the first to fourth inventions, wherein the second hydraulic pump is a fixed displacement pilot pump.

According to the above configuration, since the second hydraulic pump is an existing fixed displacement pilot pump, the second hydraulic pump has a simple structure and good durability, and usually has sufficient capacity in terms of load. By supplying pressure oil to the hydraulic motor for driving the fan, the capacity of the pilot pump is utilized to the maximum. Therefore, the total cost becomes easy.

In a sixth aspect based on any one of the first to fourth aspects, the second hydraulic pump is a variable displacement pilot pump.

According to the above configuration, since the second hydraulic pump is an existing variable displacement pilot pump, the second hydraulic pump usually has sufficient capacity in terms of load, and supplies pressure oil to the hydraulic motor for driving the cooling fan. By doing so, the capacity of the pilot pump is maximized. Further, the horsepower consumption can be minimized by controlling the capacity.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulically driven cooling fan device according to the present invention will be described below in detail with reference to FIGS.

FIG. 1 is a hydraulic circuit diagram of the hydraulically driven cooling fan device of the first embodiment. A steering circuit 14, which is a discharge circuit of the variable displacement steering pump 10, is connected to a steering valve 16 via a first check valve 15. The steering pump 10 has a swash plate control cylinder 11, and when the swash plate control cylinder 11 is extended by applying hydraulic pressure to the bottom side, the swash plate moves to the MIN side to reduce the discharge amount, and the hydraulic pressure is applied to the head side. When the swash plate is reduced by the addition of, the swash plate moves to the MAX side and the discharge amount increases. The head side of the swash plate control cylinder 11 is connected to the steering circuit 14, and the bottom side is connected to the steering circuit 14 via the cutoff valve 12 and the load sensing valve 13. Load sensing valve 13 is in drain position A
And a pressing position B. One side of the cutoff valve 12 is connected to the steering circuit 14, and the other side of the cutoff valve 12 is connected to the oil tank 5. The branch circuit 20 of the steering circuit 14 merges with the pilot circuit 31 which is the discharge circuit of the fixed displacement pilot pump 30 via the second check valve 21 and the control valve 22 to form a merge circuit 32. Merging circuit 32
Is connected to a hydraulic motor 4 for driving the cooling fan 3 to supply pressure oil. Further, the branch circuit 20 is connected via a pressure control valve 24 to an accumulator 25 and a pressure proportional control valve 26 which operates a working machine operation valve (not shown) by pilot pressure. Next, the configuration of the pump displacement control means will be described. The merging circuit 32 is connected to a thermo valve 7 that operates according to the radiator water temperature by a control circuit 33, and the thermo valve 7 is connected to the oil tank 5 by a drain circuit 8. An aperture 34 is provided in the control circuit 33. The pump control circuit 23 and the control circuit 33 connected to the steering valve 16 are connected to a pilot operation unit on one side of the load sensing valve 13 by a circuit 36 via a two-way check valve 35. Further, the pilot operation section on the other side of the load sensing valve 13 is connected to the steering circuit 14.

Next, the operation will be described. The cutoff valve 12 serves as a relief valve of the steering pump 10, and a detailed description thereof will be omitted. The pressure oil of the pilot pump 30 is
1. Drive the hydraulic motor 4 through the merging circuit 32 to rotate the cooling fan 3. When the radiator water temperature is high, the thermo valve 7 is closed, and the pressure of the control circuit 33 is high. When the steering valve 16 is in the neutral state, the pump control circuit 23 is in communication with the oil tank 5 and the pressure is low. Therefore, the pressure oil of the control circuit 33 acts on the pilot operation unit on one side of the load sensing valve 13 via the two-way check valve 35 and the circuit 36, and the drain position A
Switch to. Therefore, the head side of the swash plate control cylinder 11 becomes high pressure, and the bottom side is drained to become low pressure.
Discharge amount is increased. The pressure oil of the steering pump 10 passes through the steering circuit 14 and the branch circuit 20 and passes through the control valve 22.
Is opened, and is joined with the discharge oil of the pilot hydraulic pump 30 by the joining circuit 32 to drive the hydraulic motor 4. Therefore,
The hydraulic motor 4 is driven at high speed, and the cooling fan 3 rotates at high speed to cool the radiator. On the other hand, accumulator 2
When the oil pressure of 5 drops below a predetermined pressure, the pressure control valve 24 opens, and the pressure oil of the branch circuit 20 is supplied to the accumulator 25 and the pressure proportional control valve 26.

When the radiator water temperature decreases, the thermo valve 7 opens a predetermined amount according to the water temperature. Aperture 3 of control circuit 33
The pressure oil downstream of 4 is drained from the drain circuit 8 via the thermo valve 7, the hydraulic pressure of the circuit 36 is reduced, and the load sensing valve 13 is switched to the pressurized position B. Therefore, the pressure oil of the steering circuit 14 is supplied to the bottom side of the swash plate control cylinder 11, and the discharge amount of the steering pump 10 decreases. Therefore, the amount of oil supplied to the hydraulic motor 4 decreases, the rotation speed of the cooling fan 3 decreases, and the radiator water temperature increases.

The above operation will be described with reference to the graph of FIG. FIG. 2 is a graph showing the relationship between the engine speed and the discharge amount of the hydraulic pump supplied to the cooling fan driving hydraulic motor. The horizontal axis indicates the engine speed and the vertical axis indicates the discharge amount of the hydraulic pump. In the drawing, a line A is a discharge amount curve of the pilot pump 30, and a line B is a combined discharge amount curve of the steering pump 10 and the pilot pump 30. In both cases, the discharge amount is linear from the engine low idle rotation to the high idle rotation. Increase. When the temperature of the cooling water is low, the flow rate is controlled by the thermo valve 7 to MIN shown by the solid line a,
At a high temperature, the flow rate is controlled to MAX shown by a solid line b. In this example, the discharge amount of the pilot pump 30 is approximately MIN at the time of engine high idling. Therefore, the flow rate control is performed in the steering pump 10, and is controlled by the pump displacement control means within a range surrounded by a solid line shown in the drawing during operation. In the figure, the thin two-dot chain line shows the flow rate of the conventional hydraulic pump for cooling fan, and as is apparent from the figure, the combined flow rate of the cooling fan device of the present invention is larger than that of the conventional one. Thus, a sufficient amount of oil can be supplied even when the engine is running at a low speed. Therefore, the radiator water temperature can be constantly maintained at an appropriate temperature, and the consumed horsepower for driving the fan can be reduced. Further, in the above configuration, a hydraulic pump dedicated to driving the cooling fan is not required, and the cost can be reduced.

FIG. 3 is a hydraulic circuit diagram of the hydraulically driven cooling fan device according to the second embodiment. Portions of the pilot pump 30 other than the flow control means are the same as those in the first embodiment, and thus description thereof will be omitted, and only different portions will be described. Merging circuit 3
A drain circuit 40 having a first flow control valve 41 is connected to 2, and a second flow control valve 42 is provided between a connection point of the drain circuit 40 of the merging circuit 32 and a connection point of the control circuit 33. I have. First flow control valve 41 and second flow control valve 42
Is connected to the thermo valve 7, the other pressure receiving part of the first flow control valve 41 is connected to the pilot circuit 31, and the other pressure receiving part of the second flow control valve 42 is connected to the control circuit 33. The pump capacity control means is connected with the load sensing valve 13.

Next, the operation will be described. When the radiator water temperature is high, the thermo valve 7 is closed, and the control circuit 33 is at a high pressure, so that the first flow control valve 41 is closed and the second flow control valve 42 is open. Therefore, the entire amount of oil discharged from the pilot pump 30 and the steering pump 10 is supplied to the hydraulic motor 4, and the cooling fan 3 is driven at a high speed. When the radiator water temperature becomes low, the thermo valve 7 opens according to the temperature, and the first flow control valve 41 and the second
The pressure receiving part on one side of the flow control valve 42 has a low pressure, the first flow control valve 41 opens by a predetermined amount, and the second flow control valve 42 closes by a predetermined amount. Therefore, a part of the discharge oil of the pilot pump 30 and the steering pump 10 is drained through the first flow control valve 41, and the merging circuit 32 is partially throttled by the second flow control valve 42 and supplied to the hydraulic motor 4. Oil decreases, and thus the rotation speed of the cooling fan 3 decreases.

The above operation will be described with reference to the graph of FIG. The horizontal axis of the graph indicates the engine speed, and the vertical axis indicates the flow rate of the hydraulic pump. A line C in the figure is a discharge amount curve of the pilot pump 30, and a line D is a combined discharge amount curve of the steering pump 10 and the pilot pump 30. In this example, the discharge amount of the pilot pump 30 is configured to be larger than the MIN flow rate when the engine speed is higher than the predetermined value K. Therefore, when the MIN flow rate is equal to or less than the engine speed K, the discharge amount of the steering pump 10 is controlled by the thermo valve 7. When the MIN flow rate exceeds K, the discharge amount of the steering pump 10 is controlled and the discharge amount of the pilot pump 30 is controlled. , First and second flow control valves 41 and 42
Is controlled by controlling.

FIG. 5 is a hydraulic circuit diagram of the hydraulically driven cooling fan device of the third embodiment. It is the same as the first embodiment except for the pilot pump section. Therefore, description of the same parts will be omitted, and only different parts will be described. The pilot circuit 31 of the variable displacement pilot pump 30a is a branch circuit 20 of the steering circuit 14.
And a merging circuit 32 is formed. The junction circuit 32 is connected to the hydraulic motor 4 for driving the cooling fan. The head side of the swash plate control cylinder 11a of the pilot pump 30a is connected to the pilot circuit 31, and the bottom side is connected to the pilot circuit 31 via the cutoff valve 12a and the load sensing valve 13a. Thermo valve 7
The upstream side is connected to the two-way check valve 35 and a pilot operation unit on one side of the load sensing valve 13 by a circuit 43, and is connected to the load sensing valve 13a by a circuit 45 having a throttle 44. The downstream side of the thermo valve 7 is connected to the oil tank 5. That is, the pump displacement control means is constituted together with the load sensing valves 13 and 13a.

Next, the operation will be described. When the radiator water temperature is high, the thermo valve 7 is closed. Therefore, the load sensing valves 13 and 13a are at the position A, and the steering pump 10 and the pilot pump 3
The discharge amount of Oa is large, and the hydraulic motor 4 is rotated at high speed. When the radiator water temperature is low, the thermo valve 7 opens. Therefore, the load sensing valve 13,
The pressure on the pilot operation unit on one side of 13a becomes low, the position is switched to the position B, the discharge amount of the steering pump 10 and the pilot pump 30a decreases, and the hydraulic motor 4 rotates at low speed.

The above operation is graphically shown in FIG. 4, and the flow rate is controlled by controlling the discharge of the steering pump 10 and the pilot pump 30a by the thermo valve 7.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a hydraulically driven cooling fan device according to a first embodiment of the present invention.

FIG. 2 is a graph showing a relationship between an engine rotation and a pump discharge amount according to the first embodiment.

FIG. 3 is a hydraulic circuit diagram of a hydraulically driven cooling fan device according to a second embodiment of the present invention.

FIG. 4 is a graph showing a relationship between an engine rotation and a pump discharge amount according to a second embodiment.

FIG. 5 is a hydraulic circuit diagram of a hydraulically driven cooling fan device according to a third embodiment of the present invention.

FIG. 6 is a hydraulic circuit diagram of a conventional hydraulic drive cooling fan device.

FIG. 7 is a graph showing a relationship between a conventional engine rotation and a pump discharge amount.

[Explanation of symbols]

 Reference Signs List 3 cooling fan 4 hydraulic motor 7 thermo valve 10 steering pump 11 swash plate control cylinder 12, 12a cut-off valve 13, 13a load sensing valve 14 steering circuit 20 branch circuit 22 control valve 30, 30a pilot pump 31 pilot circuit 32 merge circuit 35 Two-way check valve 41 First flow control valve 42 Second flow control valve

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3H045 AA04 AA10 AA16 AA24 AA33 AA34 AA35 BA19 BA32 CA24 DA15 DA25 DA42 EA16 EA26 EA33

Claims (6)

[Claims] 1. A plurality of hydraulic pumps having at least a first hydraulic pump and a second hydraulic pump for operating a work machine, a steering wheel, a pilot-type operation valve, a transmission, and the like, and a hydraulic motor for driving a cooling fan of an engine radiator. In a hydraulically driven cooling fan device for a construction machine equipped with a hydraulic circuit (4), a branch circuit branched from a discharge circuit of a first hydraulic pump and a discharge circuit of a second hydraulic pump are joined and a hydraulic motor (4) for driving a cooling fan is combined. A hydraulically driven cooling fan device comprising: a merging circuit (32) for supplying oil; and pump displacement control means for controlling a discharge amount of a first hydraulic pump based on a water temperature of a radiator. 2. A hydraulic motor for driving a cooling fan of an engine radiator, a plurality of hydraulic pumps having at least a first hydraulic pump and a second hydraulic pump for operating a work machine, a steering wheel, a pilot type operation valve, a transmission, and the like. The hydraulic drive cooling fan device for a construction machine provided with: a branch circuit branched from the discharge circuit of the first hydraulic pump and the discharge circuit of the second hydraulic pump, and the hydraulic circuit (4) for driving the cooling fan A hydraulically driven cooling fan device comprising: a merging circuit (32) for supplying oil; and pump displacement control means for controlling the discharge amounts of the first hydraulic pump and the second hydraulic pump based on the water temperature of the radiator. . 3. The hydraulically driven cooling fan device according to claim 1, wherein the first hydraulic pump is a variable displacement steering pump.
0), and the discharge circuit joining the joining circuit (32) is a steering circuit (14) from a steering pump (10). 4. The hydraulically driven cooling fan device according to claim 1, wherein the first hydraulic pump is a variable displacement steering pump.
The second hydraulic pump is a pilot pump (30), and the discharge circuit that joins the merge circuit (32) includes a steering circuit (14) from the steering pump (10) and a steering circuit (14) from the pilot pump (30). A hydraulically driven cooling fan device comprising a pilot circuit (31). 5. The hydraulically driven cooling fan device according to claim 1, wherein the second hydraulic pump is a fixed displacement pilot pump (30). 6. The hydraulically driven cooling fan device according to claim 1, wherein the second hydraulic pump is a variable displacement pilot pump (30a).