JP4979638B2 - Control device for hybrid construction machine - Google Patents

Description

  The present invention relates to a control device that controls a construction machine such as a power shovel.

The hybrid structure in construction machines such as power shovels, in principle, drives the pump with the engine. For example, the generator is rotated with the surplus output of the engine, or the generator is rotated with the exhaust energy of the actuator. In addition to generating electric power, the electric motor is rotated using the electric power of the generator to operate the actuator and the like.
JP 2002-275945 A

In the above-described conventional apparatus, the main pump is rotated by the engine. For example, when the engine is started by operating an ignition key, a load at the time of starting the main pump acts on the engine. The load of this pump becomes an overload with respect to the engine whose rotational speed is not sufficiently increased, and the engine rotates while discharging graphite. As a matter of course, this graphite has a problem of becoming a major cause of pollution.
Also, until the engine maintains a certain number of revolutions and the circuit system maintains the standby state, work using the actuator of the construction machine cannot be performed, so it takes time to start up until the standby state is maintained. There was also a problem.
An object of the present invention is to provide a control device for a hybrid construction machine that can reduce the load on the engine at the time of startup and shorten the rise time.

A first aspect of the present invention is a variable capacity main pump that rotates with the driving force of an engine, a regulator that controls the tilt angle of the main pump, a circuit system that includes a plurality of operation valves and is connected to the main pump, A neutral flow path through which the discharge flow rate of the main pump flows when the operation valve of the above circuit system is held in a neutral position, and a pilot pressure that is provided in this neutral flow path and generates a high pressure when a flow occurs in the neutral flow path A generating mechanism and a pilot flow path for guiding the pilot pressure generated by the pilot pressure generating mechanism to the regulator are provided.
In addition, a check valve that is provided on the discharge side of the main pump and allows only the flow from the main pump to the operation valve, a sub pump that rotates by the driving force of the electric motor, and one of them connected to the discharge side of the sub pump The other end is connected to the downstream side of the check valve, the pilot passage is connected to the sub-pump, the electromagnetic on-off valve is provided on the pilot passage, and is provided on the downstream side of the electromagnetic on-off valve. And an unloading valve for switching to the open position by the pressure action on the downstream side of the electromagnetic on-off valve and unloading the upstream side of the check valve.

  The second invention includes a pilot pump that rotates coaxially with the main pump, a valve group that switches the discharge pressure of the pilot pump as a pilot pressure, and a pressure reducing valve that is provided in a pilot passage connected to the sub pump. The pilot passage connected to the sub pump is connected to the discharge side of the pilot pump, and the upstream pressure of the pressure reducing valve is guided to the pilot chamber of the unload valve. The configuration keeps the open position.

  The third invention is provided with a controller connected to the ignition key of the engine, the electromagnetic on-off valve, and the electric motor. This controller has a function of driving the electric motor to rotate the sub pump when the ignition key is operated, a function of switching the electromagnetic on / off valve to the open position after rotating the sub pump, and an opening of the electromagnetic on / off valve. It has a function to rotate the engine.

  In a fourth aspect of the invention, a pressure sensor is provided in a pilot flow path connected to the pilot pressure generating mechanism, and the pilot pressure detected by the pressure sensor is input to the controller. The controller includes a function of driving the electric motor to rotate the sub pump when the ignition key is operated, a function of switching the electromagnetic on-off valve to the open position after rotating the sub pump, and an opening of the electromagnetic on-off valve. And a function of reducing the discharge amount of the sub pump when the discharge amount of the sub pump flows into the neutral flow path and the pressure signal from the pressure sensor reaches a preset pressure.

  In a fifth aspect of the invention, the controller switches the electromagnetic on-off valve to the open position and then switches the unload valve to the open position to unload the main pump, while the engine speed reaches a preset speed. A function to close the solenoid on-off valve and turn it on after a predetermined time has elapsed since the operation of the ignition key, or a function to reduce the discharge amount of the sub pump when the electromagnetic on-off valve is closed And.

According to the first to fourth aspects of the invention, when starting the engine, the discharge side of the main pump can be unloaded to make it unloaded, so that the load at the time of starting the engine can also be reduced. Therefore, the start-up of the engine at the time of start-up is accelerated, and there is no problem that graphite is discharged due to an overload acting on the engine as in the prior art.
Even when the main pump is in the unloaded state, the discharge amount of the sub pump is guided to the neutral flow path. In this way, the pilot pressure can be generated by the pilot pressure generating mechanism with the discharge amount of the sub pump guided to the neutral flow path. Therefore, the main pump maintains a tilt angle corresponding to the generated pilot pressure.

  According to the second aspect of the present invention, when the controller is instructed to rotate the electric motor to secure the discharge amount of the sub pump and open the electromagnetic on-off valve, the pressure on the upstream side of the pressure reducing valve provided in the pilot passage is unloaded. Acting on the valve to open it, the discharge amount of the sub pump is supplied to the discharge side of the pilot pump. Thus, the standby state from the rotation of the electric motor to the discharge of the sub pump to the neutral flow path and the discharge side of the pilot pump can be continuously executed without waste.

  According to the third invention, the controller drives the electric motor to rotate the sub-pump when the ignition key is operated, and switches the electromagnetic on-off valve to the open position. Since the engine is rotated, the engine is rotated after the standby state is prepared, such as securing the pilot flow rate. Therefore, the engine can be rotated with a light load and can reach a predetermined number of rotations in a short time, so that the construction machine can be put into a working state in a short time after the engine is stopped.

According to the fourth invention, it is possible to shorten the rise time from the operation of the ignition key until the standby state is maintained.
According to the fifth aspect of the invention, the standby state can be set in a short time while reducing the engine load. That is, when the ignition key is operated, first, the electric motor rotates, so that the assist flow rate is supplied from the sub pump to the operation valve group. At the same time, the electromagnetic on-off valve is switched to the open position, so that a pilot pressure for the operation valve group is secured and the unload valve is switched to the open position. Therefore, in the circuit system, the pilot pressure is generated by the pilot pressure generating mechanism, and the tilt angle of the main pump is maintained at the minimum angle by the pilot pressure. However, in this state, the main pump has not yet rotated.
At the stage where the above process has passed, the controller rotates the engine. When the engine rotates in this way, the main pump also rotates. At this time, the tilt angle is maintained at the almost minimum angle as described above, so the main pump is unloaded while discharging a small flow rate. At the same time, the pilot pump also rotates.
When the engine speed reaches the predetermined speed from the above state or when a preset time has elapsed since the ignition key was operated, the electromagnetic on-off valve switches to the closed position and the main pump is switched off. At the same time as on-loading, the sub-pump discharge volume is reduced. Therefore, the discharge amount of the main pump and the reduced discharge amount of the sub pump are supplied to the circuit system. When the discharge amount of the sub pump finally becomes zero, the main pump secures the standby flow rate without the assist flow rate.
In such sequence control, it is possible to set the standby state in a short time while reducing the engine load.

The illustrated embodiment is a control device for a power shovel, and includes variable displacement first and second main pumps MP1 and MP2 and a fixed displacement pilot pump PP that rotate coaxially with the driving force of an engine E.
The first main pump MP1 is connected to the first circuit system and is provided with a regulator 1 for controlling the tilt angle. The second main pump MP2 is connected to the second circuit system and is provided with a regulator 2 for controlling the tilt angle.
The first circuit system includes, in order from the upstream side thereof, an operation valve 3 for a swing motor that controls the swing motor RM, an operation valve 4 for an arm 1 speed that controls an arm cylinder (not shown), and a boom cylinder BC. An operation valve 5 for the second speed of the boom to be controlled, a spare operation valve 6 for controlling the spare attachment (not shown), and an operation valve 7 for the left running motor (not shown) for controlling the left running motor are connected. ing.

Each of the operation valves 3 to 7 is connected to the first main pump MP1 via the neutral flow path 8 and the parallel path 9. A pilot pressure generating mechanism 10 is provided in the neutral flow path 8 downstream of the operation valve 7 for the left travel motor. The pilot pressure generating mechanism 10 generates a high pilot pressure if the flow rate flowing therethrough is large, and generates a low pilot pressure if the flow rate is small.
The neutral flow path 8 guides all or part of the fluid discharged from the first main pump MP1 to the tank when all of the operation valves 3 to 7 are in the neutral position or near the neutral position. Since the flow rate that passes through the pilot pressure generation mechanism 10 sometimes increases, a high pilot pressure is generated as described above.

On the other hand, when the operation valves 3 to 7 are switched in a full stroke state, the neutral flow path 8 is closed and the fluid does not flow. Therefore, in this case, the flow rate flowing through the pilot pressure generating mechanism 10 is almost eliminated, and the pilot pressure is maintained at zero.
However, depending on the operation amount of the operation valves 3 to 7, a part of the pump discharge amount is guided to the actuator and a part is guided to the tank from the neutral flow path 8. A pilot pressure corresponding to the flow rate flowing through the flow path 8 is generated. In other words, the pilot pressure generating mechanism 10 generates a pilot pressure corresponding to the operation amount of the operation valves 3 to 7.

A pilot flow path 11 is connected to the pilot pressure generating mechanism 10, and the pilot flow path 11 is connected to the regulator 1. The regulator 1 thus configured controls the discharge amount of the first main pump MP1 in inverse proportion to the pilot pressure. Therefore, when the flow of the neutral flow path 8 becomes zero by full stroke of the operation valves 3 to 7, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 10 becomes zero, the first main pump MP1 The discharge amount is kept at the maximum.
A first pressure sensor 12 is connected to the pilot flow path 11 as described above, and a pressure signal detected by the first pressure sensor 12 is input to the controller C.

  On the other hand, the second circuit system includes, in order from the upstream side thereof, a right travel motor operation valve 13 that controls a right travel motor (not shown), and a bucket operation valve that controls a bucket cylinder (not shown). 14, a boom first speed operation valve 15 for controlling the boom cylinder BC and an arm second speed operation valve 16 for controlling an arm cylinder (not shown) are connected. The boom first speed operation valve 15 is provided with a sensor (not shown) for detecting the operation direction and the operation amount.

The operation valves 13 to 16 are connected to the second main pump MP2 via a neutral flow path 17, and the bucket operation valve 14 and the boom first speed operation valve 15 are connected to the second main pump MP2 via a parallel passage 18. It is connected to the main pump MP2.
A pilot pressure generating mechanism 19 is provided in the neutral flow path 17 and downstream of the operation valve 16 for the second arm speed. The pilot pressure generating mechanism 19 is the pilot pressure generating mechanism 10 described above. And function in exactly the same way.

A pilot flow path 20 is connected to the pilot pressure generating mechanism 19, and the pilot flow path 20 is connected to a regulator 2 that controls the tilt angle of the second main pump MP2. The regulator 2 thus configured controls the discharge amount of the second main pump MP2 in inverse proportion to the pilot pressure. Accordingly, when the flow of the neutral flow path 17 becomes zero by full stroke of the operation valves 13 to 16, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 19 becomes zero, the second main pump MP2 The discharge amount is kept at the maximum.
The pilot flow path 20 is connected to the second pressure sensor 21 and the pressure signal detected by the second pressure sensor 21 is input to the controller C.

  The fluid discharged from the pilot pump PP is guided to a pilot path of a valve group such as the operation valves 3 to 7 and 13 to 16 described above. Therefore, these valve groups are switched by the action of the pilot pressure discharged from the pilot pump PP by operating an operation lever (not shown).

Next, the variable displacement sub-pump SP that rotates using the electric motor MG also serving as a generator as a drive source will be described.
The sub-pump SP rotates coaxially with a variable displacement assist motor AM, which will be described later. An inclination controller 22 that controls the inclination angle is connected to the controller C, and the sub-pump SP is controlled according to a signal from the controller C. The tilt angle of the SP is controlled. In addition, the electric motor MG for rotating the sub pump SP is also connected to the controller C via the inverter I so that the electric motor MG can be started and stopped or the number of rotations can be controlled in accordance with a signal from the controller C. ing.

A discharge passage 23 is connected to the sub pump SP as described above. The discharge passage 23 is connected to the discharge side of the first main pump MP1 and the discharge of the second main pump MP2. The first and second proportional electromagnetic throttle valves are branched to a second joining passage 25 that joins the first and second joining passages 24 and 25, and their opening degrees are controlled by the output signal of the controller C. 26 and 27 are provided.
In the figure, reference numerals 28 and 29 are check valves provided in the first and second merging passages 24 and 25, respectively, and permit only the flow from the sub pump SP to the merging point of the first and second main pumps MP1 and MP2. is there.
Also, first and second check valves 30 and 31 are provided upstream of the junction point between the first and second junction passages 24 and 25 and the first and second main pumps MP1 and MP2, as viewed from the main pump. However, the first and second check valves 30 and 31 allow only the flow from the first and second main pumps MP1 and MP2 to the first and second circuit systems. Therefore, the discharge fluid of the sub pump SP does not flow back to the first and second main pumps MP1 and MP2.

  Further, a pilot passage 32 is connected to the discharge passage 23 connected to the sub pump SP, and the pilot passage 32 is joined to the discharge side of the pilot pump PP. The pilot passage 32 is provided with an electromagnetic on-off valve 33 and a pressure reducing valve 34 from the upstream side toward the pilot pump PP. The solenoid opening / closing valve 33 is connected to the controller C with a solenoid provided therein, and normally maintains the illustrated closed position, but is switched to the open position by an output signal of the controller C.

  On the other hand, unload passages 35 and 36 are connected to the upstream side of the first and second check valves 30 and 31 provided on the discharge side of the first and second main pumps MP1 and MP2. 36, an unload valve 37 is provided. The unload valve 37 normally maintains the illustrated closed position by the action of a spring 37a, and closes both unload passages 35 and 36. And it switches by the pressure effect | action of the pilot chamber 37b provided in the opposite side to the said spring 37a, and connects the unload channel | paths 35 and 36 to a tank. Further, the pilot chamber 37 b is connected between the electromagnetic on-off valve 33 and the pressure reducing valve 34. Therefore, when the electromagnetic on-off valve 33 is opened and the fluid from the sub pump SP flows into the pilot passage 32, pressure is generated on the upstream side of the pressure reducing valve 34, but the pressure acts on the pilot chamber 37b of the unload valve 37. The unload valve 37 is opened.

When an ignition switch (not shown) of the engine E is turned on, the controller C first rotates the electric motor MG. At this time, the sub pump SP maintains the maximum tilt angle via the tilt controller 22. To do.
Therefore, if the electric motor MG rotates, fluid is discharged from the sub pump SP. At this time, since the controller C opens the electromagnetic on-off valve 33, the discharge pressure of the sub pump SP is reduced by the pressure reducing valve 34 and the pilot pump. In addition to being guided to the PP discharge side, it is also guided to the pilot path described above.
Further, when the discharge fluid of the sub pump SP passes through the pressure reducing valve 34 as described above, a pressure is generated on the upstream side thereof. This pressure becomes the pilot pressure of the unloading valve 37 and opens the unloading valve 37. Switch to the position and put the first and second main pumps MP1, MP2 into the unloaded state. Thus, the electromagnetic on-off valve 33 is opened and the controller C starts the engine E. At this time, since the first and second main pumps MP1 and MP2 are in the unloaded state, the load is reduced when the engine E is started.

Further, when the ignition key is operated as described above and the sub pump SP rotates, the controller C controls the opening degree of the first and second proportional electromagnetic throttle valves 26 and 27 to control the first and second check valves 30 and 31. Fluid is supplied downstream. When fluid is supplied to the downstream side of the first and second check valves 30 and 31 in this way, the fluid is returned to the tank via the neutral flow paths 8 and 17 and the pilot pressure generating mechanisms 10 and 19.
Accordingly, the pilot pressure is generated by the pilot pressure generating mechanisms 10 and 19, and this pilot pressure acts on the regulators 1 and 2 to reduce the tilt angles of the first and second main pumps MP1 and MP2, and the discharge amount thereof. To the standby flow rate. At this time, the pilot pressure signal generated by the pilot pressure generating mechanisms 10 and 19 is input to the controller C via the first and second pressure sensors 12 and 21.

  The controller C that has received the signals from the first and second pressure sensors 12 and 21 as described above receives the engine E while maintaining the standby state of the first and second circuit systems connected to the first and second main pumps MP1 and MP2. When the motor reaches a predetermined rotational speed or a predetermined time elapses after the ignition key is operated, the electromagnetic on-off valve 33 is switched to the closed position and the discharge amount of the sub pump SP is decreased. As a means for reducing the discharge amount of the sub pump SP, either the tilt angle of the sub pump SP may be reduced or the rotational speed of the electric motor MG may be reduced. When the tilt angle of the sub pump SP is reduced, the controller C is controlled via the tilt angle controller 22, and when the rotation speed of the electric motor MG is decreased, the controller C is controlled via the inverter I.

Next, a variable displacement assist motor AM that rotates coaxially with the sub-pump SP will be described.
The assist motor AM whose tilt angle is controlled by the tilt controller 55 connected to the controller C is connected to a connection passage 42, which is connected to the introduction passage 43 and the check valves 44, 45. To the passages 46 and 47 connected to the turning motor RM. In addition, the introduction passage 43 is provided with an electromagnetic switching valve 48 that is controlled to be opened and closed by the controller C, and between the electromagnetic switching valve 48 and the check valves 44 and 45, the pressure at the time of turning of the turning motor RM or the time of braking. A pressure sensor 49 for detecting the pressure of the pressure sensor 49 is provided, and the pressure signal of the pressure sensor 49 is input to the controller C.
When the controller C receives a pressure signal within a range that does not affect the turning or braking operation of the turning motor RM and lower than the set pressure of the brake valves b1 and b2, the controller C opens the electromagnetic switching valve 48. To switch a part of the pressure fluid of the swing motor RM to the assist motor AM.

  A safety valve 50 is provided at a position downstream of the electromagnetic switching valve 48 with respect to the flow from the turning motor RM to the connection passage 42 in the introduction passage 43. The safety valve 50 For example, when the electromagnetic switching valve 48 or the like breaks down and remains open or when the connection passage 42 fails, the pressure of the passages 46 and 47 is maintained and the swing motor RM makes a so-called escape. Is to prevent.

Further, the boom cylinder BC is provided with a proportional solenoid valve 52 in a passage process connecting the piston side chamber 51a and the operation valve 15, and a connection passage 42 is provided between the piston side chamber 51a and the proportional solenoid valve 52. A communication passage 53 is connected, and an electromagnetic valve 54 controlled by the controller C is provided in the passage 53.
When the operation valve 15 is switched to connect the rod side chamber 51b of the boom cylinder BC to the second main pump MP2 and the piston side chamber 51a communicates with the tank, the controller C is provided on the operation valve 15. The operation status of the valve 15 is recognized through a sensor (not shown). When the controller C recognizes the operation state of the operation valve 15, the controller C completely closes the proportional solenoid valve 52 and switches the solenoid valve 54 to the open position. When the electromagnetic valve 54 is switched to the open position in this manner, the return fluid in the piston side chamber 51a of the boom cylinder BC is supplied to the assist motor AM.

  On the other hand, when the engine E is started as described above and the first and second circuit systems connected to the first and second main pumps MP1 and MP2 are kept in the standby state, the electromagnetic on-off valve 33 is closed and the sub pump SP is turned on. After that, the controller C performs assist control of the sub-pump SP based on signals from the first and second pressure sensors 12, 21 and the like. The sub pump SP and the assist motor AM at this time function as follows.

For example, when a relatively high pressure signal is input from the first and second pressure sensors 12 and 21 to the controller C, the controller C determines that the first and second main pumps MP1 and MP2 maintain the minimum discharge amount. Then, the tilt angle controllers 22 and 55 are controlled, and the tilt angles of the sub pump SP and the assist motor AM are made zero or minimum.
When the controller C receives a signal indicating that the discharge amount of the first and second main pumps MP1 and MP2 is minimum as described above, the controller C may stop the rotation of the electric motor MG, or the rotation thereof. May be continued.
When the rotation of the electric motor MG is stopped, there is an effect that power consumption can be saved. When the electric motor MG is continuously rotated, the sub pump SP and the assist motor AM are also continuously rotated. There is an effect that the shock at the start-up of the motor AM can be reduced. In any case, whether to stop or continue to rotate the electric motor MG may be determined according to the application and usage status of the construction machine.

If the operation valve of either the first circuit system or the second circuit system is switched in the above situation, the flow rate flowing through the neutral flow path 8 or 17 is reduced according to the operation amount, and accordingly the pilot pressure generating mechanism The pilot pressure generated at 10 or 19 is also reduced. If the pilot pressure is thus reduced, the first main pump MP1 or the second main pump MP2 increases the tilt angle to increase the discharge amount.
Further, when increasing the discharge amount of the first main pump MP1 or the second main pump MP2 as described above, the controller C keeps the electric motor MG always rotated. That is, when the electric motor MG is stopped when the discharge amounts of the first and second main pumps MP1 and MP2 are minimum, the controller C senses that the pilot pressure has decreased and restarts the electric motor MG. Start.
Then, the controller C controls the opening degree of the first and second proportional electromagnetic throttle valves 26 and 27 according to the pressure signals of the first and second pressure sensors 12 and 21, and apportions the discharge amount of the sub pump SP. Supplied to the first and second circuit systems.

On the other hand, when the assist motor AM obtains a rotational force, the rotational force acts on the electric motor MG that rotates coaxially. The rotational force of the assist motor AM acts as an assist force on the electric motor MG. Therefore, the power consumption of the electric motor MG can be reduced by the amount of the rotational force of the assist motor AM.
Further, the rotational force of the sub pump SP can be assisted by the rotational force of the assist motor AM. At this time, the assist motor AM and the sub pump SP are combined to exert a pressure conversion function.

That is, the fluid pressure flowing into the connection passage 42 is often lower than the pump discharge pressure. In order to maintain the high discharge pressure in the sub pump SP by using this low pressure, the assist motor AM and the sub pump SP exhibit a pressure increasing function.
That is, the output of the assist motor AM is determined displacement volume to Q ₁ per rotation and the product of pressure P ₁ at that time. The output of the sub pump SP is determined by the product of the displacement volume Q ₂ per revolution and the discharge pressure P ₂ . In this embodiment, since the assist motor AM and the sub pump SP rotate coaxially, Q ₁ × P ₁ = Q ₂ × P ₂ must be satisfied. Therefore, for example, if the displacement volume to _{Q 1} assist motor AM was tripled i.e. _Q 1 = 3Q ₂ volume _{Q 2} displacement of the sub pump SP, this equation does _{3Q 2 × P 1 = Q 2} × the P _2. If both sides are divided by Q ₂ from this equation, 3P ₁ = P ₂ holds.
Therefore, by changing the tilt angle of the sub pump SP, by controlling the displacement volume Q _2, the output of the assist motor AM, it is possible to maintain the predetermined discharge pressure sub pump SP.

  The electric motor MG can be used as a generator with the assist motor AM as a drive source. At this time, the tilt angle of the sub-pump SP is set to zero and the load is almost unloaded. If the output necessary for rotating the MG is maintained, the electric motor MG can exhibit a power generation function using the output of the assist motor AM.

According to this embodiment as described above, when the ignition key is operated when starting the engine E, the controller C senses it and first rotates the electric motor MG and discharges the pressure fluid from the sub pump SP. Let
The controller C opens the first and second proportional electromagnetic throttle valves 26 and 27 and switches the electromagnetic on-off valve 33 to the open position. When the electromagnetic opening / closing valve 33 is switched to the open position, the discharge fluid of the sub pump SP flows into the pilot passage 32 and is supplied to the discharge side of the pilot pump PP via the pressure reducing valve 34. The pressure fluid supplied to the discharge side of the pilot pump PP in this way is supplied to the valve group through the pilot path described above, and keeps the valve group in a state where it can be switched at any time.

Further, the pressure on the upstream side of the pressure reducing valve 34 acts on the pilot chamber 37b of the unload valve 37 and switches the unload valve 37 to the open position. Therefore, the first and second main pumps MP1 and MP2 are kept in the unloaded state.
When the first and second main pumps MP1 and MP2 are in the unloaded state as described above, the controller C starts the engine E. When the engine E is started, the rotational loads of the first and second main pumps MP1 and MP2 are increased. It hardly acts on the engine E, the engine E stands up in a short time, and does not generate graphite in an overload state.

Until the engine E starts up as described above, the first and second main pumps MP1 and MP2 are kept in an unloaded state, but the neutral flow paths 8 and 17 of the first and second circuit systems are connected to the sub pump SP. Since the discharge fluid is supplied from the pilot pressure, the pilot pressure generating mechanisms 10 and 19 generate a high pilot pressure. Therefore, by the action of the high pilot pressure, the first and second main pumps MP1 and MP2 are maintained at the tilt angle necessary for maintaining the standby flow rate, and the first and second circuit systems are maintained in the standby state.
When the discharge fluid of the sub pump SP is supplied to the neutral flow paths 8 and 17 as described above, the first and second check valves 30 and 31 function, so that the discharge fluid of the sub pump SP is unloaded. Never happen.

Then, the controller C keeps the main pumps MP1 and MP2 of the first and second circuit systems in the standby state, and the engine E reaches a predetermined rotational speed. After operating the ignition key, the controller C While closing the on-off valve 33, the discharge amount of the sub pump SP is decreased.
As described above, the controller C continuously performs the activation of the electric motor MG, the control of the discharge fluid of the sub pump SP, the unload control of the first and second main pumps MP1 and MP2, the startup of the engine E, etc. from the operation of the ignition key. Run without waste.

1 is a circuit diagram showing an embodiment of the present invention.

Explanation of symbols

E Engine MP1 1st main pump MP2 2nd main pump 1, 2 Regulator PP Pilot pump 3-7 Operation valve 8 Neutral flow path 10 Repilot pressure generation mechanism 11 Pilot flow path 12 First pressure sensor C Controllers 13-16 Operation valve 17 Neutral flow path 19 Pilot pressure generating mechanism 20 Pilot flow path 21 Second pressure sensor SP Sub pump MG Electric motors 24, 25 First and second merge paths 30, 31 First and second check valves 32 Pilot path 33 Electromagnetic on-off valve 34 Depressurization Valve 37 Unload valve

Claims (5)

  A variable capacity main pump that rotates by the driving force of the engine, a regulator that controls the tilt angle of the main pump, a circuit system that is provided with a plurality of operation valves and is connected to the main pump, and an operation valve of the circuit system A neutral flow path through which the discharge flow rate of the main pump flows when the pump is held in a neutral position, a pilot pressure generating mechanism that is provided in the neutral flow path and generates a high pressure when a flow occurs in the neutral flow path, and the pilot In a construction machine having a pilot flow path that guides the pilot pressure generated by the pressure generating mechanism to the regulator, a check valve that is provided on the discharge side of the main pump and allows only the flow from the main pump to the operation valve; Connect the sub-pump that rotates with the driving force of the electric motor, one to the discharge side of the sub-pump, and the other The confluence passage connected to the downstream side of the check valve, the pilot passage connected to the sub pump, the electromagnetic on-off valve provided in the pilot passage, and the pressure action on the downstream side of the electromagnetic on-off valve is normally kept closed. A control device for a hybrid construction machine, comprising: an unload valve that switches to an open position and unloads the upstream side of the check valve.   A pilot pump that rotates coaxially with the main pump, a valve group that switches the discharge pressure of the pilot pump as a pilot pressure, and a pressure reducing valve that is provided in a pilot passage connected to the sub pump. The pilot passage connected to the sub pump 2. The system according to claim 1, wherein the pilot pump is connected to the discharge side of the pilot pump, the pressure upstream of the pressure reducing valve is guided to a pilot chamber of the unload valve, and the unload valve is maintained in the open position by the pressure action of the pilot chamber. The control apparatus of the described hybrid construction machine.   A controller connected to the ignition key of the engine, the electromagnetic on-off valve and the electric motor is provided, and this controller rotates the sub pump by driving the electric motor when the ignition key is operated. The control device for a hybrid construction machine according to claim 1 or 2, further comprising a function of switching the electromagnetic on-off valve to an open position after the operation and a function of rotating the engine after the electromagnetic on-off valve is opened.   A pressure sensor is provided in the pilot flow path connected to the pilot pressure generating mechanism, and the pilot pressure detected by the pressure sensor is input to the controller. The controller drives the electric motor when the ignition key is operated. The function of rotating the sub pump, the function of switching the electromagnetic on / off valve to the open position after rotating the sub pump, the function of rotating the engine after the electromagnetic on / off valve is opened, and the discharge amount of the sub pump flow into the neutral flow path The control device for a hybrid construction machine according to any one of claims 1 to 3, further comprising a function of reducing a discharge amount of the sub-pump when a pressure signal from the pressure sensor reaches a preset pressure.   The controller switches the solenoid on / off valve to the open position and then switches the unload valve to the open position to unload the main pump, while the engine speed reaches the preset speed or the ignition key A function of closing the electromagnetic on-off valve and turning it on after a predetermined time has elapsed since the operation of the controller, and a function of reducing the discharge amount of the sub-pump when the electromagnetic on-off valve is closed. 4. The control device for a hybrid construction machine according to 4.

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