JPH11351147A - Control device for hydraulic driven generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device in a simple structure as a whole capable of supplying pressure oil to two hydraulic actuators in a well-balanced manner without running short of a discharge flow rate from a hydraulic pump by using a generating hydraulic motor for driving a generator in common with the hydraulic pump connected to the other hydraulic actuator and varying a flow rate supplied to the other hydraulic actuator. SOLUTION: Pressure oil discharged from a hydraulic pump 30 is switched either to a condition that the pressure oil is only supplied to a fan driving hydraulic motor 32 and to a condition that the pressure oil is supplied to both hydraulic motor 32, 34, by a flow passage switching means 35. A switching signal is taken in a controller 45 to switch an electromagnetic switch valve 46 in accordance with a detection temperature signal for operating oil from an oil temperature sensor 44, while the hydraulic pump 30 is operated in the minimum flow condition, so that the pressure oil is supplied to a regulator 48 in the condition that pilot pressure in a pilot pump 47 is reduced by a pressure reducing valve 49 to cause tilting change in the direction of increasing the discharge flow rate of the hydraulic pump 30 is increase the discharge flow rate into an intermediate flow condition.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a hydraulic motor for driving a fan for an oil cooler and a hydraulic motor for driving a generator as a power supply for lighting an illumination lamp. A hydraulic drive generator driven by a hydraulic actuator and another hydraulic actuator are driven by the same variable displacement hydraulic pump, and the supply flow rate to the other hydraulic actuator is changed. Also, the present invention relates to a control device of a hydraulic drive generator that controls a discharge flow rate of a hydraulic pump so that a supply flow rate to both hydraulic actuators does not become insufficient when the generator operates.

[0002]

2. Description of the Related Art A hydraulic shovel is an example of a machine equipped with a hydraulically driven generator. Hydraulic shovels are driven by hydraulic oil from a hydraulic pump, for example, a hydraulic motor drives the vehicle and turns the upper revolving unit, and a hydraulic cylinder drives the front working mechanism. It is of a hydraulic drive type equipped with a hydraulic actuator. To this end, a hydraulic pump driven by a prime mover and a hydraulic oil tank as a supply source of hydraulic oil are installed, and the hydraulic motor is driven to rotate by the prime mover so that hydraulic oil is sucked into the hydraulic pump from the hydraulic oil tank and added. This hydraulic oil is supplied to each hydraulic actuator.
Also, the return oil from the hydraulic actuator is returned to the hydraulic oil tank, but since the return oil is hot,
After being cooled by an oil cooler, it is returned to the hydraulic oil tank.

[0003] As described above, in a hydraulic circuit including a hydraulic pump, a hydraulic actuator, and a hydraulic oil tank, the temperature of hydraulic oil flowing through the hydraulic circuit must always be maintained within a predetermined range. If the oil temperature exceeds the set range, the viscosity of the hydraulic oil is reduced, which causes inconveniences such as damage to seal members provided at various parts. However, when the temperature of the hydraulic oil is too low, the flow of the hydraulic oil in the hydraulic circuit is deteriorated, and quick and smooth movement of each part is hindered, and the load on the hydraulic pump also increases. It is for this reason that an oil cooler is provided to cool the return oil, and the oil cooler cools the working oil returned from each hydraulic actuator or the like by cooling air.

Here, an oil cooler is provided side by side with a radiator, and a fan is driven to rotate by a prime mover to supply cooling air to the oil cooler and the radiator.
There is a type in which an oil cooler is arranged separately from a radiator and driven by independent fans. When the oil cooler is placed separately from the radiator, the fan is not driven by the prime mover, but a hydraulic motor is used as its driving means. However, the hydraulic motor for driving the fan is driven by a hydraulic pump that is independent of the hydraulic motor for driving the traveling, turning, and front working mechanisms, because it does not require high-pressure hydraulic oil with a large flow rate, unlike the hydraulic actuator for driving the traveling, turning, and front working mechanisms. It is common to configure so that

[0005] The oil cooler is not for cooling the working oil, but for keeping the working oil always within a predetermined temperature range. The cooling efficiency of the working oil flowing in the oil cooler mainly depends on the rotation speed of the fan. That is, if the rotation speed of the fan is increased, the temperature of the hydraulic oil is reduced accordingly. However, depending on the situation, when the fan is rotated at a high speed, the temperature of the hydraulic oil may be too low to be lower than an appropriate temperature. For this reason, in order to make the rotation speed of the fan variable, detect the temperature of the hydraulic oil in the hydraulic oil tank, and change the rotation speed of the fan according to the oil temperature, for example, as shown in FIG. A configuration is conceivable.

In FIG. 1, reference numeral 1 denotes a hydraulic pump, 2 denotes a hydraulic motor for driving a fan, and 3 denotes a fan for supplying cooling air to an oil cooler. Here, in the drawing, two fan driving hydraulic motors 2 and two fans 3 are provided, and the two hydraulic motors 2 and 2 are connected to the hydraulic pump 1 in parallel. The hydraulic pump 1 is of a variable displacement type, and is configured so as to control the discharge flow rate by supplying pressure oil from a pilot pump 4 to a regulator 5. This is a mechanism for controlling the tilt of the vehicle.

Reference numeral 6 denotes an oil temperature sensor, 7 denotes a controller, and 8 denotes rotation speed switching means. The oil temperature sensor 6 is provided in a hydraulic oil tank or the like, and is for measuring the temperature of the hydraulic oil. A signal from the oil temperature sensor 6 is taken into the controller 7 and is based on a signal from the controller 7. Thus, the discharge flow rate of the hydraulic pump 1 is changed in three stages by the rotation speed switching means 8. This rotation speed switching means 8
5 is enlarged in FIG. As is apparent from this figure, the electromagnetic switching valve 9 and the pressure reducing valve 10 constitute the rotation speed switching means 8. The electromagnetic switching valve 9 has three switching positions (H), (M) and (L). At the intermediate switching position (H), the pilot pressure from the pilot pump 4 is supplied to the regulator 5 as it is,
When switched to the left switching position (M), the pilot pressure from the pilot pump 4 is reduced by the pressure reducing valve 10, that is, the pilot pressure of the cracking pressure of the spring 10a acting on the pressure reducing valve 10 is supplied. Further, at the right switching position (L) in the figure, the pilot pressure from the pilot pump 4 is not supplied to the regulator 4, and the regulator 4 is connected to the hydraulic oil tank 11.

Here, the regulator 4 is a so-called negative control, and when the pilot pressure from the pilot pump 4 is supplied to the regulator 5 as it is, the hydraulic pump 1 is in the minimum tilt state, and the discharge flow rate is minimized. As a result, the fan drive hydraulic motor 2 rotates at a low speed. When the regulator 4 is connected to the hydraulic oil tank 11, the hydraulic pump 1 is in the maximum tilt state, and the discharge flow rate is maximized. As a result, the fan driving hydraulic motor 2 rotates at high speed. When the pilot pressure is supplied to the regulator 4 in a state where the pilot pressure is reduced through the pressure reducing valve 10, the discharge flow rate of the hydraulic pump 1 is in an intermediate state, and the fan drive hydraulic motor 2 rotates at a medium speed.

The fan 3 by the fan driving hydraulic motor 2
The rotation speed of the solenoid valve is switched by taking the temperature detection signal of the working oil from the oil temperature sensor 6 into the controller 7, and based on the conditions preset in the controller 7, the electromagnetic pilot portion 9a or This is performed by exciting 9b. The controller 7 has three temperature ranges, high, medium and low, set according to the upper and lower limits of the operating oil temperature. The operating oil temperature detected by the oil temperature sensor 6 is lower than the lower limit. If
Both electromagnetic pilot sections 9a and 9b are kept in a demagnetized state,
The electromagnetic switching valve 9 is held at the position H) shown, and the hydraulic pump 1 is in the minimum tilt state. In the middle temperature range where the oil temperature is between the upper limit value and the lower limit value, the electromagnetic pilot unit 9a is excited, and the electromagnetic switching valve 9 is switched to the switching position (M) on the left side in FIG. The discharge flow rate is in an intermediate state set by the pressure reducing valve 10. Further, when the controller 7 determines that the oil temperature is in the high temperature region higher than the upper limit, the electromagnetic pilot portion 9b is excited and the electromagnetic switching valve 9 is turned on.
Is switched to the right switching position (L), so that the discharge flow rate of the hydraulic pump 1 is maximized.

With the above-described configuration, the cooling air supplied to the oil cooler can be switched in three stages according to the temperature of the hydraulic oil flowing through the hydraulic circuit, so that the controllability of the hydraulic oil temperature is good. And has an excellent feature that the temperature can be reliably maintained within a predetermined temperature range.

[0011]

A hydraulic shovel is a hydraulic actuator driven by pressure oil supplied from a hydraulic pump, and is similar to a hydraulic actuator for driving a traveling, turning and front working mechanism. In addition to those for fan driving, there are those which do not require high-pressure oil at a high flow rate. As one example, there is a generator driven by a hydraulic motor, and this hydraulic drive generator is used, for example, as a power source for lighting an illumination lamp. Since the power generation hydraulic motor has a relatively small load and requires a small flow rate, if the hydraulic pump for supplying hydraulic oil to the power generation hydraulic motor in the hydraulic drive generator can be shared with the fan drive hydraulic motor, This is extremely advantageous because the configurations of the fan driving device and the power generation device can be simplified.

However, a mercury lamp is generally used as an illumination lamp for a hydraulic excavator from the viewpoint of life and the like, but a constant voltage must always be supplied to the mercury lamp. When the voltage drops, the mercury lamp is turned off, and once turned off, an extremely long time is required until it is turned on again. Therefore, when the fan-drive hydraulic motor and the power generation hydraulic motor are driven by the same hydraulic pump, it is necessary to ensure that the power generation hydraulic motor always has a constant flow rate. In addition, while the machine is operating, the fan always operates, but the mercury lamp operates only when sufficient visibility cannot be obtained with sunlight, such as at night.

The present applicant has developed a motor in which the fan driving hydraulic motor and the power generation hydraulic motor are driven by the same hydraulic pump, and filed a patent application as Japanese Patent Application No. 9-299634. FIG. 6 shows the configuration of the prior application.
In the drawing, reference numeral 20 denotes a prime mover, 21 denotes a hydraulic pump, and a hydraulic pump 21 (in the illustrated case, 2
Although two hydraulic pumps are shown, the fan 2 may be configured with one hydraulic pump.
, A fan driving hydraulic motor 23 for driving the
A power generation hydraulic motor 26 for driving a power generator 25 for supplying power to the power supply 4 operates.

While the hydraulic excavator is operating, the fan 22 must be driven at all times, whereas the mercury lamp 2
Reference numeral 4 is lit only when sunlight cannot be obtained, such as at night. When the mercury lamp 24 is turned on, the power generation hydraulic motor 26 is used to stabilize the voltage of the power generator 25.
Must always be supplied with a constant flow of pressure oil. From the above points, the switching valve 27 is provided in the flow path on the discharge side of the hydraulic pump 21.
And a flow dividing valve 28 and a sequence valve 29. The switching valve 27 supplies the pressure oil only to the fan drive hydraulic motor 23, and supplies the pressure oil to the power generation hydraulic motor 26 and the fan drive hydraulic motor 23 via the flow dividing valve 28 and the sequence valve 29. It can be switched to the state of shunting. And the switching valve 27
Is switched to the split state, the throttle 2 in the split valve 28
The pressure oil at the flow rate set in 8a is preferentially supplied to the hydraulic motor 26 for power generation, and the surplus flow rate is supplied to the hydraulic motor 23 for fan drive via the sequence valve 29.

Therefore, after the supply flow rate to the fan drive hydraulic motor shown in FIG. 4 is changed in a plurality of stages, the hydraulic pump is driven by the fan drive as shown in the prior application shown in FIG. The hydraulic oil motor and the hydraulic motor for power generation are used for supplying pressure oil, the temperature control of the hydraulic oil by the oil cooler is extremely good, and the configuration of the fan drive unit and the generator unit is simplified. This is further advantageous because the conversion can be realized.

However, the hydraulic motor for power generation always requires a constant flow of hydraulic oil. However, using a variable displacement hydraulic pump, the discharge flow rate of the hydraulic pump is switched in multiple stages according to the temperature of the hydraulic oil. In the case where the hydraulic oil temperature is in a low temperature range and the discharge flow rate of the hydraulic pump is in a minimum state, when the hydraulic motor for power generation is operated,
The entire discharge flow rate of this hydraulic pump is supplied to the hydraulic motor for power generation via the diverting valve, and no hydraulic oil is supplied to the hydraulic motor for fan drive, the fan stops, or the hydraulic motor for fan drive Even if pressure oil is supplied,
There is a possibility that the flow rate is insufficient, the rotation speed of the fan is significantly reduced, and sufficient cooling air cannot be supplied to the oil cooler. Further, depending on the configuration of the power generation hydraulic motor, the flow rate of the pressure oil to the power generation hydraulic motor may be insufficient in the minimum discharge flow state of the hydraulic pump.

Therefore, an object of the present invention is to share a power generating hydraulic motor for driving a generator with a hydraulic pump connected to another hydraulic actuator, and to supply flow rate to the other hydraulic actuator. To make the pressure oil variable, and to supply the pressure oil to these two hydraulic actuators in a balanced manner so that the discharge flow rate from the hydraulic pump does not become insufficient. is there.

[0018]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention drives a variable displacement hydraulic pump, a generator having a hydraulic motor for power generation, and devices other than the generator. Another hydraulic actuator for, and a flow rate variable means for changing the discharge flow rate of the hydraulic pump according to the operation status of the other hydraulic actuator, and when the power generation hydraulic motor and the other hydraulic motor are simultaneously operated ,
Distribution means for supplying a constant flow of hydraulic oil from the hydraulic pump to the generator hydraulic motor, and supplying an excess flow to the other hydraulic actuators; and When the generator is operated while the hydraulic actuator is being driven, in conjunction with this operation, the discharge flow rate of the hydraulic pump is increased by a flow rate necessary for operating the other hydraulic actuator. And a control means for controlling the flow rate varying means.

Here, even when the other hydraulic actuator is driven at the minimum flow rate or higher, the discharge flow rate of the hydraulic pump is changed in order to supply the required amount of pressure oil for the other hydraulic actuator. You can also.
On the other hand, when the other hydraulic actuator is driven at the maximum flow rate state, in order to supplement the flow rate supplied to the power generation hydraulic motor, the flow rate-pressure characteristic of the hydraulic pump is changed in the direction in which the discharge flow rate with respect to the discharge pressure increases. May be changed. The generator is used as a power supply unit for the illumination lamp, and the other hydraulic actuator may be a fan drive hydraulic motor that drives a fan for supplying cooling air to the oil cooler.

[0020]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the figure,
Numeral 30 denotes a variable displacement hydraulic pump. The hydraulic pump 30 is a fan 3 for supplying cooling air to an oil cooler.
1 and a fan drive hydraulic motor 32 for driving the
The pressure oil is supplied to the power generation hydraulic motor 34 that drives the motor 3. Therefore, the fan drive hydraulic motor 32 is
Another hydraulic actuator for the power generation hydraulic motor 34 is configured. Although two fans 31 and two fan drive hydraulic motors 32 are provided, the number depends on the structure of the oil cooler, and is not necessarily two.

The pressure oil discharged from the hydraulic pump 30 is supplied to the fan driving hydraulic motor 32 only by the flow path switching means 35 and the fan driving hydraulic motor 3
2 and a state in which pressure oil is supplied to the power generation hydraulic motor 34. The passage switching means 35 may be constituted by a switching valve which is switched manually, but in the illustrated case, the passage is switched in conjunction with a switch 36a provided on the breaker 36. ing. For this purpose, the flow path switching means 35 comprises an electromagnetic pilot valve 37 and a switching valve 38 switched by the pilot valve 37.
The switching valve 38 connects a pipe 39 on the discharge side of the hydraulic pump 30 to the fan driving hydraulic motor 32, and connects the power generating hydraulic motor 34 and the fan driving hydraulic motor 32 via the flow dividing valve 40. The switch is switched to the switching position.
N, the electromagnetic pilot unit 3 via the relay 36b
The flow is switched to the switching valve 38 by passing a current through 7a.

The flow dividing valve 40, together with a sequence valve 41 provided in a flow path between the flow dividing valve 40 and the fan driving hydraulic motor 32, transmits the hydraulic oil supplied from the hydraulic pump 30 to the power generating hydraulic motor 34 and the fan. The flow is divided into the drive hydraulic motor 32 and the power generation hydraulic motor 34, so that the flow rate set by the throttle 40a of the flow dividing valve 40 is always supplied. This power generation hydraulic motor 34
Is supplied, the sequence valve 41 is opened, and the excess hydraulic oil is supplied to the fan driving hydraulic motor 32. The power generated by the generator 33 by the operation of the power generation hydraulic motor 34 is supplied to the power supply circuit 42 including the breaker 36 described above,
The mercury lamp 43 as a lighting lamp connected to the power supply circuit 42 is turned on. Although the number of the mercury lamps 43 is four in the drawing, the number is arbitrary. Also,
Not only a mercury lamp but also an incandescent lamp may be used.

When the mercury lamp 43 is not turned on, the entire flow rate of the hydraulic pump 30 is supplied to the fan driving hydraulic motor 32 through the switching valve 38, but the rotation speed of the fan 31 is 3
It can be changed in stages. For this purpose, an oil temperature sensor 44 for measuring the temperature of the hydraulic oil in the hydraulic oil tank is provided, and the temperature detected by the oil temperature sensor 44 is taken in by a controller 45 constituting control means. Then, the controller 45 operates the electromagnetic pilot portions 46a and 46b of the electromagnetic switching valve 46 based on the detected temperature of the hydraulic oil, and the electromagnetic switching valve 46
Is performed. The above configuration is the same as that described with reference to FIG. 4, and a detailed description thereof will be omitted. In the following, the electromagnetic switching valve 46
The switching positions (H), (M), and (L) are the same as those shown in FIG. 5, and are not shown in FIG.

When the fan 31 is rotated at a low speed, both the electromagnetic pilot portions 46a and 46b are demagnetized, the electromagnetic switching valve 46 is set to the switching position (H), and the pilot pressure from the pilot pump 47 is set. To the regulator 48 directly. As a result, the regulator 48 operates to bring the hydraulic pump 30 into the minimum tilt state, and the hydraulic pump 30 into the minimum flow state. When the fan 31 is rotated at a medium speed, the electromagnetic pilot portion 46a is excited to set the electromagnetic switching valve 46 to the switching position (M), and the pilot pressure is reduced via the pressure reducing valve 49. Switch to the state to supply to. As a result, the discharge flow rate of the hydraulic pump 30 increases and enters the intermediate flow state. In addition, fan 3
When the motor 1 is rotated at a high speed, the electromagnetic switching portion 46 is switched to the switching position (L) by exciting the electromagnetic pilot portion 46b, and the connection between the pilot pump 47 and the regulator 48 is cut off. Connected to hydraulic oil tank 50. Thereby, the hydraulic pump 3
0 indicates the maximum flow state.

As described above, the electromagnetic switching valve 46, the pilot pump 47, the regulator 48, and the pressure reducing valve 49 constitute a flow rate changing means for changing the discharge flow rate of the hydraulic pump 30. The flow rate of the hydraulic pump 30 may be changed not only in three steps but also in plural steps or steplessly.

The change in the flow rate of the hydraulic pump 30 by the electromagnetic switching valve 46 is necessary for the operation of the fan 31. Also, when the machine is operating, the hydraulic oil flows through the hydraulic circuit to perform work, so that the temperature of the hydraulic oil rises. Therefore, as long as the machine is operating, the fan 31 always rotates and the oil cooler Needs to be supplied with cooling air. The rotation speed of the fan 31 is switched between low, medium, and high speeds according to the temperature detected by the oil temperature sensor 44. That is, the discharge flow rate of the hydraulic pump 30 changes according to the temperature detected by the oil temperature sensor 44.
On the other hand, when the power generation hydraulic motor 34 operates, a constant flow rate of pressure oil is required.

Now, the hydraulic excavator is operated, but the temperature of the hydraulic oil is low due to the influence of the surrounding temperature and the like, and the electromagnetic switching valve 4 is rotated to rotate the fan 31 at low speed.
6 is at the switching position (H), and the hydraulic pump 30 is in the minimum flow state. In this state, when the surrounding field of view cannot be obtained and the switch 36a is turned on to turn on the mercury lamp 43, the switching valve 38 constituting the flow path switching means 35 is switched, and the pressure oil flows to the power generation hydraulic motor 34. State. In addition, since the flow dividing valve 40 is provided, a predetermined amount of pressure oil flows to the power generation hydraulic motor 34 preferentially.

If the discharge flow rate of the hydraulic pump 30 in the minimum flow rate state is equal to or less than the flow rate required to drive the power generation hydraulic motor 34, the sequence valve 41 is kept closed. No pressure oil is supplied to the fan driving hydraulic motor 32, and the rotation of the fan 31 stops.
Further, even if a surplus flow rate is obtained and the sequence valve 41 is opened, the absolute amount of the pressure oil supplied to the fan drive hydraulic motor 32 is significantly short, and the rotation speed of the fan 31 is extremely reduced. The cooling air cannot be supplied to the oil cooler substantially.

As described above, when the power-generating hydraulic motor 34, which is continually operated, is detected by the controller 45 in accordance with the operating condition of the fan-drive hydraulic motor 32, which is constantly operating, the controller 45 detects the operation. By increasing the discharge flow rate of 30, the hydraulic oil is supplied to both hydraulic motors 32 and 34 in a well-balanced manner. In order to detect whether or not the power generation hydraulic motor 34 is operating, the switch 36a and the controller 45 are connected by a signal cable 51, and a switching element 52 is provided on the signal cable 51. The switching element 52 has a high signal level as long as the switch 36a included in the breaker 36 is ON and the switch 36a is kept ON.

Therefore, when the operation signal of the power generation hydraulic motor 34 is taken into the controller 45 via the signal cable 51, the controller 45 detects the operation signal of the operating oil from the oil temperature sensor 44. It is determined whether to increase the discharge flow rate of the pump 30. First, at least when the temperature of the hydraulic oil is low and the hydraulic pump 30 is operating at the minimum flow rate, the discharge flow rate of the hydraulic pump 30 is absolutely insufficient, and the fan 31 stops. Therefore, when the hydraulic pump for operation 34 operates when the hydraulic pump 30 is operating at the minimum flow rate, the electromagnetic pilot portion 46 a of the electromagnetic switching valve 46 is operated.
To switch from the switching position (H) to the switching position (M). As a result, the pilot pressure of the pilot pump 47 is supplied to the regulator 48 in a state where the pilot pressure is reduced by the pressure reducing valve 49.
The discharge flow rate of 0 is tilted and changed in the increasing direction, and the discharge flow rate increases to the intermediate flow rate state.

As a result, a sufficient amount of pressure oil is supplied to the power generation hydraulic motor 34, and the generator 33 is operated in a state of generating a voltage necessary to turn on the mercury lamp 43. In addition, since an excess flow is generated in the flow dividing valve 40, the sequence valve 41 is opened, and the pressure oil is also supplied to the fan driving hydraulic motor 32, so that the rotation of the fan 31 is maintained. Here, the hydraulic pump 30 operates in the intermediate flow rate state, but a predetermined flow rate is taken by the power generation hydraulic motor 34, so that the fan drive hydraulic motor 32 is supplied with a flow rate substantially equal to or less than the minimum flow rate. As a result, the distribution balance of the flow rate is improved and the fan 3
No. 1 operates in a low-speed rotation state, so that there is no inconvenience that the operating oil is supercooled. Here, switching of the switching valve 38 in the flow path switching means 35 is performed by the switch 36a.
If the operation is performed immediately when the fan 31 is turned on, the fan 31
May stop. In order to prevent this, the relay 36b is provided with a delay, the switch 36a is turned on, and the switching valve 38 is set to be switched after the discharge flow rate of the hydraulic pump 30 increases to the intermediate flow rate state. You can also.

On the other hand, when the temperature of the hydraulic oil detected by the oil temperature sensor 44 is between the upper limit value and the lower limit value, that is, in the middle temperature range, the fan 31 is operated, and when the mercury lamp 43 is turned off, the hydraulic pressure is The pump 30 is operating at an intermediate flow rate. At this time, when the switching valve 38 of the flow path switching means 35 switches to a state in which the pressure oil is also supplied to the power generation hydraulic motor 34, a constant flow of the pressure oil is supplied to the power generation hydraulic motor 34, and the excess flow rate is supplied. Since the minute is supplied to the fan drive hydraulic motor 32 by opening the sequence valve 41, the rotation of the fan 31 does not stop. However, since the supply amount to the fan drive hydraulic motor 32 is reduced by the flow rate consumed by the power generation hydraulic motor 34,
The rotation speed of the fan 31 decreases, and the cooling efficiency of the oil cooler decreases. However, as long as the temperature of the hydraulic oil is between the upper and lower limits, there is no particular problem,
As a result of the fan 31 being in the low-speed rotation state, when the temperature of the hydraulic oil rises to a high-temperature region, the electromagnetic switching valve 46 switches so as to increase the rotation speed of the fan 31.

However, in this case, in order to prevent the rotation speed of the fan 31 from decreasing, the discharge flow rate of the hydraulic pump 30 may be increased. For this, the controller 4
In 5, when a signal indicating that the switch 36a is turned on is captured, it is detected with reference to the temperature of the hydraulic oil from the oil temperature sensor 44 that the temperature of the hydraulic oil is intermediate between the upper limit value and the lower limit value. Then, the electromagnetic pilot portion 46b of the electromagnetic switching valve 46 is energized, and the electromagnetic switching valve 46 is switched to the switching position (L). As a result, the regulator 48 is connected to the hydraulic oil tank 50 and the hydraulic pump 3
0 indicates the maximum discharge flow state. Therefore, even when the rotation speed of the fan 31 is the same as the rotation speed in the middle rotation speed at the time of the independent operation, or slightly different from the rotation speed, the fan 31 rotates at the rotation speed substantially intermediate between the high rotation speed state and the low rotation speed state. Become
Again, a necessary and sufficient amount of cooling air can be supplied to the oil cooler.

As described above, when the fan drive hydraulic motor 32 is operated alone, the rotation speed of the fan 31 can be switched among three stages of low speed, medium speed and high speed. When the operating hydraulic motor 34 operates, the rotation speed of the fan 31 can be switched only to two stages of low speed and medium speed. However, the situation that requires illumination by the mercury lamp 43 is a situation where sunlight cannot be obtained, such as at night. When there is no sunlight,
Since the surrounding temperature decreases, the temperature of the hydraulic oil does not increase so much. Therefore, in a normal state, if the fan 31 is rotating at a medium speed, normally, the necessary cooling air can be supplied to the oil cooler, so that the high speed state is not always necessary.

However, assuming that the operating oil temperature is extremely high, and the fan 31 is rotating at a high speed,
When the switch 36a is turned on to drive the generator 33, the rotation speed of the fan 31 is maintained and both hydraulic motors 3
In order to create a high-speed rotation state as well as a low-speed and medium-speed rotation state of the fan 31 at the same time when the fans 2 and 34 are simultaneously operated, the pressure-flow characteristic (so-called PQ characteristic) of the hydraulic pump 30 may be changed. good. Here, the regulator 48 for controlling the tilting of the hydraulic pump 30 has a configuration schematically shown in FIG. That is, the tilting operation member 52 is
L, 53U. The position where the tilting operation member 52 contacts the stopper 53L is the minimum tilting state, that is, the minimum flow rate state, and the position where the tilting operating member 52 contacts the stopper 53U is the maximum. This is the tilt state, that is, the maximum flow state. A spring 54 for urging in the maximum tilting direction acts on the tilting operation member 52, and a pilot pressure chamber 56 for displacing in the minimum tilting direction is provided. Therefore, by guiding the pilot pressure to the pilot pressure chamber 56, the tilt angle becomes small, and the hydraulic pump 30
Discharge flow rate decreases.

Here, the PQ characteristic is changed by the urging force of the spring 54. 3, it is assumed that the spring 54 has a predetermined urging force, and the PQ characteristics in the maximum tilt state are as shown by the solid line in FIG. In FIG. 3, a range S of the pressure (P) is a range where the load is substantially acting. Assuming that the discharge pressure is Pa due to the load during the operation of the fan drive hydraulic motor 32, the discharge flow rate at that time is Qa. In this state, the spring 54 is compressed by the solenoid 55 so that the tilting operation member 5
When the spring force acting on P2 is increased, the PQ characteristics
Changes as indicated by the dotted line.

When the power generation hydraulic motor 34 is operated in addition to the fan drive hydraulic motor 32, the load on the hydraulic pump 30 increases. Therefore, the discharge pressure is Pb
The discharge flow rate at this time is Qb, which is larger than the discharge flow rate Qa when the spring 54 is not compressed. Therefore,
By compressing the spring 54 and changing the PQ characteristic so that (Qb-Qa) becomes a flow rate (ΔQ) commensurate with the operation of the power generation hydraulic motor 34, the fan drive hydraulic motor 32 Is supplied with a flow rate necessary for rotating the fan 31 at high speed. Accordingly, the hydraulic pump 30 can be driven in three stages: an intermediate flow state when the solenoid 55 is not operated, a maximum flow state when the solenoid 55 is not operated, and a flow increase state when the solenoid 55 is operated.

Therefore, the controller 45 controls the oil temperature sensor 4
When the switch 36a is turned on to drive the generator 33 when the temperature detected from the sensor 4 exceeds the upper limit and the fan 31 is operating at a high speed, the electromagnetic switching valve 46
While maintaining the switch position (L), the solenoid 55 is energized to compress the spring 54. As a result, the discharge flow rate is increased by ΔQ from the hydraulic pump 30 while maintaining the maximum tilt state, so that the rotation speed of the fan 31 does not substantially change, and the power generation hydraulic motor 34
Pressure oil at a required flow rate can be supplied.

In the above description, the case where the power generation hydraulic motor 34 is operated while the fan 31 is operating has been described. However, both the fan drive hydraulic motor 32 and the power generation hydraulic motor 34 operate. In this state, the same control is performed when the temperature detected by the oil temperature sensor 44 changes. Also, when the switch 36a is ON,
When the state is switched to the state F, it goes without saying that the controller 45 switches to the control state when the fan driving hydraulic motor 32 operates alone.

The electromagnetic switching valve 46 is switched when the power generation hydraulic motor 34 is operated while the fan 31 is operating at a medium speed. However, instead of this, a solenoid is used. 55 may be configured to operate. As a result, a constant pressure is supplied to the pilot pressure chamber 56, but the tilt angle of the hydraulic pump 30 increases by the amount of compression of the spring 54, and the PQ characteristic shows that the discharge flow rate with respect to the load pressure is small. , The discharge flow rate of the hydraulic pump 30 increases, so that the supply flow rate to the power generation hydraulic motor 34 can be secured.

[0041]

Since the present invention is constructed as described above, the power generating hydraulic motor for driving the generator is shared with the hydraulic pump connected to another hydraulic actuator, and the other hydraulic actuator is connected to the hydraulic pump. By making the supply flow rate variable, the overall configuration can be simplified, and the hydraulic oil can be supplied to these two hydraulic actuators in a well-balanced manner, resulting in a shortage of the discharge flow rate from the hydraulic pump. It has the effect of not doing.

[Brief description of the drawings]

FIG. 1 is a configuration explanatory view showing a control device of a hydraulic drive generator according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of a regulator.

FIG. 3 is a diagram showing a relationship between a spring of a regulator and PQ characteristics.

FIG. 4 is a conventional hydraulic circuit diagram showing an example of a cooling device for an oil cooler provided with a mechanism for changing the number of revolutions of a fan according to the temperature of hydraulic oil.

5 is an explanatory diagram of a configuration of a rotation speed switching unit of FIG. 4;

FIG. 6 is a hydraulic circuit diagram of a device for driving a fan driving hydraulic motor and a power generation hydraulic motor by a single hydraulic pump according to the invention of the prior application;

[Explanation of symbols]

Reference Signs List 30 hydraulic pump 31 fan 32 fan drive hydraulic motor 33 generator 34 power generation hydraulic motor 35 flow path switching means 36a switch 36b delay circuit 37 pilot valve 38 switching valve 40 shunt valve 41 sequence valve 42 power supply circuit 43 mercury lamp 44 oil temperature sensor 45 Controller 46 Solenoid switching valve 47 Pilot pump 48 Regulator 49 Pressure reducing valve 51 Signal cable 52 Switching element

Claims (3)

[Claims] 1. A variable displacement hydraulic pump, a generator having a hydraulic motor for power generation, another hydraulic actuator for driving equipment other than the generator, and an operating state of the other hydraulic actuator. Accordingly, when the flow rate varying means for changing the discharge flow rate of the hydraulic pump and the hydraulic motor for power generation and another hydraulic motor are simultaneously operated, a constant flow of hydraulic oil from the hydraulic pump to the hydraulic motor for the generator is provided. And the distribution means for supplying an excess flow rate to the other hydraulic actuator, and the generator is operated while the hydraulic pump is at least in a minimum flow state and drives the other hydraulic actuator. Sometimes, in conjunction with this operation, the flow rate variable so that the discharge flow rate of the hydraulic pump is increased by a flow rate necessary for the other hydraulic actuator to operate. And a control means for controlling the means. 2. When the other hydraulic actuator is driven at the maximum flow rate, the control means changes the flow rate-pressure characteristic of the hydraulic pump in a direction in which the discharge flow rate with respect to the discharge pressure increases. The control device for a hydraulically driven generator according to claim 1, wherein 3. The power generator for supplying power to an illumination lamp, and the other hydraulic actuator is a fan drive hydraulic motor for driving a fan for supplying cooling air to an oil cooler. The control device for a hydraulic drive generator according to claim 1 or 2.