JP2009235718A - Controller of hybrid construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for a hybrid construction machine capable of minimizing the number of sensors.
A controller C, based on operation signals of the swing motor RM and other actuators, regulators 10 and 20 of a main pump MP, an inclination controller 35 of a sub pump SP, an inclination controller 36 of an assist motor AM, and While controlling the electric motor MG and controlling the opening and closing of the electromagnetic switching valve 46 according to the signal from the pressure sensor 47, when a pressure signal lower than the turning pressure of the turning motor RM but close thereto is inputted from the pressure sensor 47, A configuration in which the electromagnetic on-off valve is opened, and the pressure fluid in the passages 26 and 27 for the swing motor is guided from the merging passage 43 to the assist motor AM via the safety valve 48 to assist the output of the electric motor with the driving force of the assist motor I have to.
[Selection] Figure 1

Description

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

Hybrid structures in construction machines such as power shovels, for example, rotate a generator with surplus output of the engine to generate electricity, store the power in a battery, and drive the electric motor with the battery power to operate the actuator I try to let them. Further, the generator is rotated by the energy discharged from the actuator to generate electric power, and the electric power is similarly stored in the battery, and the electric motor is driven by the electric power of the battery to operate the actuator.
JP 2002-275945 A

In the above-described conventional control device, there is a problem that the energy loss during the process is large because the process until the exhaust energy of the actuator that operates by the surplus output of the engine or the fluid pressure is regenerated to the operation of the actuator is long.
In addition, since the actuator is operated by the electric motor, for example, when the electric system fails, there is a problem that the apparatus itself becomes unusable.
The object of the present invention is to use the energy of the swing motor as the assist force of the electric motor and, if necessary, to use it as the energy for causing the electric motor to exhibit the power generation function, thereby eliminating the above-mentioned conventional problems. It is to provide a control device for a construction machine.

  The first invention is a variable capacity main pump, a regulator for controlling the tilt angle of the main pump, a plurality of operation valves connected to the main pump, and an operation for a swing motor connected to the main pump. A valve, a swing motor connected to the swing motor via a pair of swing motor passages, a brake valve provided between the swing motor passages, and a discharge angle of the main pump and tilt angle control Variable displacement sub-pump whose tilt angle is controlled by a generator, variable displacement assist motor whose tilt angle is controlled by a tilt controller, and an electric motor also serving as a generator that rotates these sub-pump and assist motor together A merging passage that joins the pair of turning motor passages, a passage that communicates the joining passage with the assist motor, and a passage for the turning motor. And a check valve that allows only flow from the turning motor passage to the joining passage, an electromagnetic switching valve that opens and closes the joining passage, and the solenoid switching valve and the check valve. A pressure sensor; a safety valve provided in the merging passage between the electromagnetic switching valve and the assist motor; and a controller that receives a pressure signal of the pressure sensor and performs a control function.

  The controller controls the main pump regulator, the sub pump tilt controller, the assist motor tilt controller and the electric motor based on the operation signals of the swing motor and other actuators, and the pressure sensor. The electromagnetic switching valve is controlled to open and close according to the signal. Also, when a pressure signal that is lower than the swing pressure of the swing motor but close to it is input from the pressure sensor, the electromagnetic on-off valve is opened and the pressure fluid in the swing motor passage is guided from the merge passage to the assist motor via the safety valve. Thus, the output of the electric motor is assisted by the driving force of the assist motor.

According to a second aspect of the present invention, a boom cylinder is connected to one of the plurality of operation valves, and a passage for guiding return fluid from the piston side chamber of the boom cylinder to the connection passage is provided.
According to a third aspect of the present invention, a check valve that allows only the flow from the sub pump to the main pump is provided in a passage process for communicating the sub pump and the main pump, and a spring spring is provided for the passage process for communicating the swing motor and the assist motor. An electromagnetic switching valve that maintains the normal position, which is the closed position by force, is provided.
In a fourth aspect of the invention, the main pump is configured to rotate with the driving force of the engine linked to the generator, while a battery for storing electric power supplied to the electric motor is provided, and a battery charger is connected to the battery. The battery charger is connected to the generator and can be connected to an independent power source such as a household power source different from the device.

According to the first invention, the assist motor is driven using the fluid energy of the swing motor, and the electric motor that is the drive source of the sub pump is assisted by the drive force of the assist motor. Can be used efficiently.
In addition, since a safety valve is provided between the electromagnetic switching valve and the assist motor, it is possible to prevent the swing motor from running away even if fluid leaks between the electromagnetic switching valve and the assist motor.
According to the second invention, when the swing motor and the boom cylinder are simultaneously operated, their fluid energy can be used efficiently.
According to the third invention, when a failure or the like occurs in the circuit system of the sub pump and the assist motor, the circuit system can be separated from the circuit system of the main pump.
According to the fourth invention, the power source of the electric motor can be diversified.

The embodiment shown in FIG. 1 is a control device for a power shovel and includes variable capacity type first and second main pumps MP1 and MP2, and a first circuit system is connected to the first main pump MP1, and a second A second circuit system is connected to the main pump MP2.
The first circuit system includes, in order from the upstream side, an operation valve 1 for a swing motor that controls the swing motor RM, an operation valve 2 for an arm 1 speed that controls an arm cylinder (not shown), and a boom cylinder BC. A control valve 3 for the second speed of the boom to be controlled, a preliminary operation valve 4 for controlling the preliminary attachment (not shown), and a control valve 5 for the left traveling motor (not shown) for controlling the left traveling motor are connected. ing.

Each of the operation valves 1 to 5 is connected to the first main pump MP1 via the neutral flow path 6 and the parallel path 7.
A pilot pressure generating mechanism 8 is provided in the neutral flow path 6 on the downstream side of the operation valve 5 for the left travel motor. The pilot pressure generating mechanism 8 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 6 guides all or part of the fluid discharged from the first main pump MP1 to the tank T when all of the operation valves 1 to 5 are in the neutral position or in the vicinity of the neutral position. At this time, since the flow rate passing through the pilot pressure generating mechanism 8 also increases, a high pilot pressure is generated as described above.
On the other hand, when the operation valves 1 to 5 are switched in a full stroke state, the neutral flow path 6 is closed and the fluid does not flow. Therefore, in this case, there is almost no flow rate flowing through the pilot pressure generating mechanism 8, and the pilot pressure is maintained at zero.
However, depending on the operation amount of the operation valves 1 to 5, a part of the pump discharge amount is guided to the actuator and a part is guided to the tank T from the neutral flow path 6. A pilot pressure corresponding to the flow rate flowing through the neutral flow path 6 is generated. In other words, the pilot pressure generating mechanism 8 generates a pilot pressure corresponding to the operation amount of the operation valves 1 to 5.

A pilot flow path 9 is connected to the pilot pressure generating mechanism 8, and the pilot flow path 9 is connected to a regulator 10 that controls the tilt angle of the first main pump MP1. The regulator 10 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 6 becomes zero by full stroke of the operation valves 1 to 5, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 8 becomes zero, the first main pump MP1 The discharge amount is kept at the maximum.
A first pressure sensor 11 is connected to the pilot flow path 9 as described above, and a pressure signal detected by the first pressure sensor 11 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 12 for controlling a right travel motor (not shown) and a bucket operation valve for controlling a bucket cylinder (not shown). 13. A boom first speed operation valve 14 for controlling the boom cylinder BC and an arm second speed operation valve 15 for controlling an arm cylinder (not shown) are connected. The boom first speed operation valve 14 is provided with a sensor 14a for detecting an operation direction and an operation amount thereof.

The operation valves 12 to 15 are connected to the second main pump MP2 through the neutral flow path 16, and the bucket operation valve 13 and the boom first speed operation valve 14 are connected to the second main pump MP2 through the parallel passage 17. It is connected to the main pump MP2.
A pilot pressure generating mechanism 18 is provided in the neutral flow path 16 downstream of the operation valve 15 for the second arm speed. The pilot pressure generating mechanism 18 is the pilot pressure generating mechanism 8 described above. And function in exactly the same way.

A pilot flow path 19 is connected to the pilot pressure generating mechanism 18, and the pilot flow path 19 is connected to a regulator 20 that controls the tilt angle of the second main pump MP2. The regulator 20 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 16 becomes zero by full stroke of the operation valves 12 to 15, in other words, when the pilot pressure generated by the pilot pressure generating mechanism 18 becomes zero, the second main pump MP2 The discharge amount is kept at the maximum.
The pilot pressure channel 19 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 first and second main pumps MP1 and MP2 configured as described above rotate coaxially with the driving force of one engine E. The engine E is provided with a generator 22 so that the generator 22 can be powered by the surplus output of the engine E. The electric power generated by the generator 22 is charged to the battery 24 via the battery charger 23.
The battery charger 23 can charge the battery 24 even when connected to a normal household power supply 25. That is, the battery charger 23 can be connected to an independent power source different from the device.

Further, passages 26 and 27 communicating with the turning motor RM are connected to the actuator port of the operation valve 1 for the turning motor connected to the first circuit system, and brake valves 28 and 27 are respectively connected to the passages 26 and 27. 29 is connected. When the operation valve 1 for the swing motor is maintained at the neutral position shown in the drawing, the actuator port is closed and the swing motor RM maintains the stopped state.
When the operation valve 1 for the swing motor is switched from the above state to, for example, the right side position in the drawing, one passage 26 is connected to the first main pump MP1, and the other passage 27 communicates with the tank T. Accordingly, the pressure fluid is supplied from the passage 26 to rotate the turning motor RM, and the return fluid from the turning motor RM is returned to the tank T through the passage 27.
When the operation valve 1 for the swing motor is switched to the left position, the pump discharge fluid is supplied to the passage 27, the passage 26 communicates with the tank T, and the swing motor RM is reversed. .

  When the swing motor RM is driven as described above, the brake valve 28 or 29 functions as a relief valve, and when the passages 26 and 27 become the set pressure or higher, the brake valves 28 and 29 are opened. Thus, the fluid on the high pressure side is guided to the low pressure side. Further, when the swing motor RM is rotated and the swing motor operating valve 1 is returned to the neutral position, the actuator port of the control valve 1 is closed. Thus, even if the actuator port of the operation valve 1 is closed, the swing motor RM continues to rotate with its inertial energy, but the swing motor RM performs a pumping action as the swing motor RM rotates with the inertial energy. At this time, the passages 26 and 27, the turning motor RM, and the brake valve 28 or 29 form a closed circuit, and the inertia energy is converted into heat energy by the brake valve 28 or 29.

On the other hand, when the operation valve 14 for the first speed of the boom is switched from the neutral position to the right side of the drawing, the pressure fluid from the second main pump MP2 is supplied to the piston side chamber 31 of the boom cylinder BC through the passage 30. The return fluid from the rod side chamber 32 is returned to the tank T via the passage 33, and the boom cylinder BC is extended.
On the contrary, when the operation valve 14 for the first speed of the boom is switched to the left in the drawing, the pressure fluid from the second main pump MP2 is supplied to the rod side chamber 32 of the boom cylinder BC via the passage 33, and The return fluid from the piston side chamber 31 is returned to the tank T via the passage 30, and the boom cylinder BC contracts. The operation valve 3 for the second speed of the boom is switched in conjunction with the operation valve 14 for the first speed of the boom.
A proportional electromagnetic valve 34 whose opening degree is controlled by the controller C is provided in the passage 30 connecting the piston-side chamber 31 of the boom cylinder BC and the first-speed boom operating valve 14 as described above. The proportional solenoid valve 34 is kept in the fully open position in its normal state.

Next, the variable displacement sub pump SP that assists the outputs of the first and second main pumps MP1 and MP2 will be described.
The variable displacement sub-pump SP is rotated by the driving force of the electric motor MG that also serves as a generator, and the variable displacement assist motor AM is also rotated coaxially by the driving force of the electric motor MG. An inverter I is connected to the electric motor MG, and the inverter I is connected to a controller C so that the controller C can control the rotational speed of the electric motor MG.
The tilt angles of the sub-pump SP and the assist motor AM as described above are controlled by tilt controllers 35 and 36. These tilt controllers 35 and 36 are controlled by the output signal of the controller C. is there.

  A discharge passage 37 is connected to the sub pump SP. The discharge passage 37 joins the first joining passage 38 that joins to the discharge side of the first main pump MP1 and the discharge side of the second main pump MP2. The first and second merge passages 38 and 39 branch to the second merge passage 39, and the first and second proportional electromagnetic throttle valves 40 and 41 whose opening degree is controlled by the output signal of the controller C are respectively provided. Provided.

  On the other hand, a connection passage 42 is connected to the assist motor AM. This connection passage 42 is connected to passages 26 and 27 connected to the turning motor RM via a junction passage 43 and check valves 44 and 45. is doing. In addition, the merging passage 43 is provided with an electromagnetic switching valve 46 that is controlled to be opened and closed by the controller C, and between the electromagnetic switching valve 46 and the check valves 44 and 45, when the swinging motor RM is turned or braked. A pressure sensor 47 for detecting the pressure of the pressure sensor 47 is provided, and the pressure signal of the pressure sensor 47 is input to the controller C.

In addition, a safety valve 48 is provided at a position downstream of the electromagnetic switching valve 46 with respect to the flow from the turning motor RM to the connection passage 42 in the junction passage 43. The safety valve 48 Is to prevent the turning motor RM from running away by maintaining the pressure in the passages 26 and 27 when a failure occurs in the connection passages 42 and 43 such as the electromagnetic switching valve 46.
Further, a passage 49 communicating with the connection passage 42 is provided between the boom cylinder BC and the proportional solenoid valve 34, and an electromagnetic opening / closing valve 50 controlled by the controller C is provided in the passage 49. .

In the following, the operation of this embodiment will be described. In this embodiment, the assist flow rate of the sub pump SP is set in advance, and among them, the controller C determines the tilt angle of the sub pump SP, the assist motor AM. Each control is performed by determining how to control the tilt angle, the number of rotations of the electric motor MG, and the like to be most efficient.
Now, if the operation valves 1 to 5 of the first circuit system are maintained at the neutral position, the total amount of fluid discharged from the first main pump MP1 is transferred to the tank T via the neutral flow path 6 and the pilot pressure generating mechanism 8. Led. When the total discharge amount of the first main pump MP1 flows through the pilot pressure generating mechanism 8 in this way, the pilot pressure generated there becomes high and a relatively high pilot pressure is also introduced into the pilot flow path 9. The regulator 10 is operated by the action of the high pilot pressure guided to the pilot flow path 9, and the discharge amount of the first main pump MP1 is kept to a minimum. The high pilot pressure signal at this time is input from the first pressure sensor 11 to the controller C.

  Further, when the operation valves 12 to 15 of the second circuit system are kept at the neutral position, the pilot pressure generating mechanism 18 generates a relatively high pilot pressure and the high pressure as in the case of the first circuit system. The pressure acts on the regulator 20 to keep the discharge amount of the second main pump MP2 to a minimum. The high pilot pressure signal at this time is input from the pressure sensor 21 to the controller C.

When a relatively high pressure signal is input from the first and second pressure sensors 11 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. Thus, the tilt angle controllers 35 and 36 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 amounts of the first and second main pumps MP1 and MP2 are minimum as described above, the controller C may stop the rotation of the electric motor MG, The rotation 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 the electric motor MG or continue to rotate may be determined in accordance with the use 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 6 or 16 decreases according to the operation amount, and accordingly, the pilot pressure generating mechanism The pilot pressure generated at 8 or 18 is 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 detects 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 40 and 41 according to the pressure signals of the first and second pressure sensors 11 and 21, and apportions the discharge amount of the sub pump SP. Supplied to the first and second circuit systems.
As described above, according to this embodiment, the controller C controls the tilt angle of the sub-pump SP and the first and second proportional electromagnetic throttle valves 40 and 41 only with the pressure signals of the two first and second pressure sensors 11 and 21. The number of pressure sensors can be reduced.

On the other hand, in order to drive the turning motor RM connected to the first circuit system, when the operation valve 1 for the turning motor is switched to either the left or right, for example, the right side of the drawing, one passage 26 is connected to the first main pump MP1. The other passage 27 communicates with the tank T to rotate the turning motor RM. At this time, the turning pressure is maintained at the set pressure of the brake valve 28. When the operation valve 1 is switched to the left in the drawing, the other passage 27 communicates with the first main pump MP1 and the one passage 26 communicates with the tank T to rotate the turning motor RM. The turning pressure at this time is also maintained at the set pressure of the brake valve 29.
Further, when the swing motor operating valve 1 is switched to the neutral position while the swing motor RM is turning, a closed circuit is formed between the passages 26 and 27 as described above, and the brake valve 28 or 29 is provided. Maintains the closed circuit brake pressure and converts inertial energy into thermal energy.

The pressure sensor 47 detects the turning pressure or the brake pressure and inputs the pressure signal to the controller C. When the controller C detects a pressure lower than the set pressure of the brake valves 28 and 29 within a range that does not affect the turning or braking operation of the turning motor RM, the controller C opens the electromagnetic switching valve 46 from the closed position to the open position. Switch to. When the electromagnetic switching valve 46 is switched to the open position in this way, the pressure fluid guided to the turning motor RM flows into the merge passage 43 and is supplied to the assist motor AM via the safety valve 48 and the connection passage 42. The
At this time, the controller C controls the tilt angle of the assist motor AM in accordance with the pressure signal from the pressure sensor 47, which is as follows.

That is, unless the pressure in the passage 26 or 27 is maintained at a pressure required for the turning operation or the braking operation, the turning motor RM cannot be turned or the brake cannot be applied.
Therefore, in order to keep the pressure in the passage 26 or 27 at the turning pressure or the brake pressure, the controller C controls the load of the turning motor RM while controlling the tilt angle of the assist motor AM. . That is, the controller C controls the tilt angle of the assist motor AM so that the pressure detected by the pressure sensor 47 becomes substantially equal to the turning pressure or the brake pressure of the turning motor RM.

If the assist motor AM obtains a rotational force as described above, 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 necessarily lower than the pump discharge pressure. In order to maintain a 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. In other words, the fluid pressure from the turning motor RM can be increased and discharged from the sub pump SP.

However, the tilt angle of the assist motor AM is controlled so as to keep the pressure in the passages 26 and 27 at the turning pressure or the brake pressure as described above. Therefore, when the fluid from the turning motor RM is used, the tilt angle of the assist motor AM is inevitably determined. In this way, the tilt angle of the sub-pump SP is controlled in order to exert the above-described pressure conversion function while the tilt angle of the assist motor AM is determined.
When the pressure in the connection passages 42 and 43 is lower than the turning pressure or the brake pressure for some reason, the controller C closes the electromagnetic switching valve 46 based on the pressure signal from the pressure sensor 47. The rotation motor RM is not affected.
When fluid leaks in the connecting passage 42, the safety valve 48 functions to prevent the pressure in the passages 26 and 27 from becoming unnecessarily low, thereby preventing the turning motor RM from running away.

Next, a case where the boom cylinder BC is controlled by switching the boom first speed operation valve 14 and the boom second speed operation valve 3 of the first circuit system in conjunction therewith will be described.
When the operation valve 14 for the first speed of the boom and the operation valve 3 interlocked therewith are switched to operate the boom cylinder BC, the operation direction and the operation amount of the operation valve 14 are detected by the sensor 14a. An operation signal is input to the controller C.

  In response to the operation signal from the sensor 14a, the controller C determines whether the operator is going to raise or lower the boom cylinder BC. If a signal for raising the boom cylinder BC is input to the controller C, the controller C keeps the proportional solenoid valve 34 in a normal state. In other words, the proportional solenoid valve 34 is kept in the fully open position. At this time, the controller C keeps the electromagnetic on-off valve 50 in the illustrated closed position and controls the rotation speed of the electric motor MG and the tilt angle of the sub pump SP so that a predetermined discharge amount is secured from the sub pump SP. .

On the other hand, when a signal for lowering the boom cylinder BC is input from the sensor 14a to the controller C, the controller C calculates the lowering speed of the boom cylinder BC requested by the operator according to the operation amount of the operation valve 14. The proportional solenoid valve 34 is closed and the solenoid on-off valve 50 is switched to the open position.
If the proportional solenoid valve 34 is closed and the solenoid on-off valve 50 is switched to the open position as described above, the entire return fluid of the boom cylinder BC is supplied to the assist motor AM. However, if the flow rate consumed by the assist motor AM is less than the flow rate required to maintain the descending speed obtained by the operator, the boom cylinder BC cannot maintain the descending speed obtained by the operator. In such a case, the controller C tanks a flow rate higher than the flow rate consumed by the assist motor AM based on the operation amount of the operation valve 14, the tilt angle of the assist motor AM, the rotation speed of the electric motor MG, and the like. The opening degree of the proportional solenoid valve 34 is controlled to return to T, and the lowering speed of the boom cylinder BC required by the operator is maintained.

On the other hand, when fluid is supplied to the assist motor AM, the assist motor AM rotates and its rotational force acts on the coaxially rotating electric motor MG. The rotational force of the assist motor AM is applied to the electric motor MG. Acts as an assist force. Therefore, power consumption can be reduced by the amount of rotational force of the assist motor AM.
On the other hand, the sub pump SP can be rotated only by the rotational force of the assist motor AM without supplying electric power to the electric motor MG. At this time, the assist motor AM and the sub pump SP are the same as described above. The pressure conversion function is demonstrated.

Next, the case where the turning operation of the turning motor RM and the lowering operation of the boom cylinder BC are simultaneously performed will be described.
When the boom cylinder BC is lowered while turning the turning motor RM as described above, the fluid from the turning motor RM and the return fluid from the boom cylinder BC merge in the connection passage 42 to the assist motor AM. Supplied.
At this time, if the pressure in the connecting passage 42 increases, the pressure on the merging passage 43 side increases accordingly. Even if the pressure becomes higher than the turning pressure or the brake pressure of the turning motor RM, the check valve 44 and 45 do not affect the turning motor RM.
If the pressure on the connection passage 42 side becomes lower than the turning pressure or the brake pressure as described above, the controller C closes the electromagnetic switching valve 46 based on the pressure signal from the pressure sensor 47.

Therefore, when the turning operation of the turning motor RM and the lowering operation of the boom cylinder BC are simultaneously performed as described above, the assist motor AM is operated on the basis of the required lowering speed of the boom cylinder BC regardless of the turning pressure or the brake pressure. The tilt angle can be determined.
In any case, the output of the sub-pump SP can be assisted by the output of the assist motor AM, and the flow rate discharged from the sub-pump SP is apportioned by the first and second proportional electromagnetic throttle valves 40 and 41 to obtain the first and second Can be supplied to the circuit system.

  On the other hand, when the electric motor MG is used as a generator with the assist motor AM as a drive source, the tilt angle of the sub-pump SP is set to zero and the load is almost unloaded, and the assist motor AM is rotated to rotate the electric motor MG. If the necessary output is maintained, the electric motor MG can exhibit the power generation function using the output of the assist motor AM.

  In this embodiment, the output of the engine E can be used to generate power with the generator 22 or the assist motor AM can be used to generate power with the electric motor MG. The power generated in this way is stored in the battery 24. In this embodiment, since the power can be stored in the battery 24 using the home power supply 25, the power of the electric motor MG is procured in various ways. be able to.

  On the other hand, in this embodiment, the assist motor AM is rotated using the fluid from the turning motor RM and the boom cylinder BC, and the sub pump SP and the electric motor MG can be assisted by the output of the assist motor AM. Energy loss until use can be minimized. For example, in the conventional case, a generator is rotated using fluid from an actuator, and an electric motor is driven using electric power stored in the generator, and the actuator is operated by the driving force of the electric motor. However, the regenerative power of the fluid pressure can be directly used as compared with this conventional device.

  FIG. 2 shows another embodiment in which the proportional solenoid valve 34 and the electromagnetic on-off valve 50 of FIG. 1 are integrated. This proportional solenoid valve 51 normally maintains the open position shown in FIG. When a signal is input from C, the position is switched to the right side of the drawing. When the proportional solenoid valve 51 is switched to the right position in the drawing, the throttle 51a is positioned in the communication process between the boom cylinder BC and the tank T, and the check valve 51b is positioned between the boom cylinder BC and the assist motor AM. It is a thing. The opening of the throttle 51a is controlled according to the switching amount of the proportional solenoid valve 51. Others are the same as the solenoid valve in FIG.

Reference numerals 52 and 53 in the figure are check valves provided on the downstream side of the first and second proportional electromagnetic throttle valves 40 and 41, and only allow flow from the sub pump SP to the first and second main pumps MP1 and MP2. To do.
Since the check valves 52 and 53 are provided as described above, and the electromagnetic switching valve 46 and the electromagnetic on-off valve 50 or the proportional electromagnetic valve 51 are provided, for example, when the sub pump SP and the assist motor AM system fail, The two main pumps MP1 and MP2 can be separated from the sub pump SP and the assist motor AM. In particular, when the solenoid switching valve 46, the proportional solenoid valve 51, and the solenoid on-off valve 50 are in the normal state, the normal solenoid position is maintained by the spring force of the spring as shown in the drawing. 34, since the proportional solenoid valve 51 also maintains the normal position which is the fully open position, even if the electric system fails, the first and second main pumps MP1 and MP2 systems, the sub pump SP and the assist motor AM system are connected as described above. Can be separated.

1 is a circuit diagram showing an embodiment of the present invention. It is a partial circuit diagram showing other embodiments of a proportional solenoid valve.

Explanation of symbols

MP1 1st main pump MP2 2nd main pump RM Swing motor 1 Swing motor operation valve 2 Arm 1 speed operation valve BC Boom cylinder 3 Boom 2 speed operation valve 4 Spare operation valve 5 Left travel motor Control valve 10 Regulator C Controller 12 Right travel motor control valve 13 Bucket operation valve 14 Boom 1st speed operation valve 15 Arm 2nd speed operation valve 20 Regulator 26, 27 Swing motor passages 28, 29 Brake valve SP Sub-pump 35, 36 Tilt controller AM Assist motor MG Electric motor 42 also serving as a generator 42 Motor connecting passage 43 Merge passage 44, 45 Check valve 46 Electromagnetic switching valve 48 Safety valve 52, 53 Check valve

Claims (4)

  A variable capacity main pump, a regulator for controlling the tilt angle of the main pump, a plurality of operation valves connected to the main pump, an operation valve for a swing motor connected to the main pump, and the swing motor A swing motor connected to the control valve via a pair of swing motor passages, a brake valve provided between the swing motor passages, and a tilt pump connected to the discharge side of the main pump and tilted by an inclination controller A variable displacement sub-pump whose angle is controlled, a variable displacement assist motor whose tilt angle is controlled by an inclination controller, an electric motor serving as a generator that integrally rotates the sub-pump and the assist motor, and the pair A merging passage for merging the slewing motor passage, a passage for communicating the merging passage with the assist motor, and the slewing motor passage for merging with the merging passage. A check valve that allows only the flow from the turning motor passage to the merge passage, an electromagnetic switching valve that opens and closes the merge passage, and a pressure sensor provided between the electromagnetic switching valve and the check valve. And a safety valve provided in the merging passage between the electromagnetic switching valve and the assist motor, and a controller that receives a pressure signal of the pressure sensor and exhibits a control function. Control the main pump regulator, sub pump tilt controller, assist motor tilt controller and electric motor based on the operation signals of other actuators, and open and close the electromagnetic switching valve according to the pressure sensor signal. On the other hand, when a pressure signal that is lower than the swivel pressure of the swivel motor but close to it is input from the pressure sensor, Control device for a hybrid construction machine configured to open the on-off valve and guide the pressure fluid in the passage for the swing motor from the merging passage to the assist motor via the safety valve and assist the output of the electric motor with the driving force of the assist motor .   2. The control device for a hybrid construction machine according to claim 1, wherein a boom cylinder is connected to one of the plurality of operation valves, and a passage for guiding a return fluid from a piston side chamber of the boom cylinder to the connection passage is provided.   A check valve that allows only the flow from the sub pump to the main pump is provided in the passage process for communicating the sub pump and the main pump, and the passage process for communicating the swing motor and the assist motor is in the closed position by the spring force of the spring. The control device for a hybrid construction machine according to claim 1 or 2, further comprising an electromagnetic switching valve for maintaining a normal position.   The main pump is configured to rotate with the driving force of the engine linked to the generator, and is provided with a battery that stores electric power supplied to the electric motor, and a battery charger is connected to the battery. The hybrid construction machine control device according to any one of claims 1 to 3, wherein the control device is connected to the generator and to an independent power source such as a household power source different from the device.

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