KR101656765B1 - Working vehicle and working vehicle control method - Google Patents

Abstract

The turning pump output calculating section calculates the turning pump output in which the output of the electric motor is converted into the output of the hydraulic pump. The reduction amount determining section determines the reduction amount of the output of the hydraulic pump in the combined operation based on the output of the swing pump. The pump output determining section determines a value obtained by subtracting the reduction amount from the output of the hydraulic pump determined in accordance with the state of the combined operation in the first control mode as the output of the hydraulic pump in the combined operation. The pump output determining section increases the output of the hydraulic pump in the combined operation in the second control mode rather than the first control mode.

Description

{WORKING VEHICLE AND WORKING VEHICLE CONTROL METHOD}

The present invention relates to a work vehicle and a control method thereof.

The working vehicle has a turning body and a working machine. For example, in the working vehicle of Patent Document 1, a swivel body is turned by a hydraulic motor, and a working machine such as a boom is driven by a hydraulic cylinder. In such a working vehicle (hereinafter referred to as " standard working vehicle "), the hydraulic motor and the hydraulic cylinder are driven by hydraulic oil discharged from the hydraulic pump.

On the other hand, as in Patent Document 2, a hybrid type work vehicle having an electric motor instead of a hydraulic motor has been recently developed. In a hybrid type working vehicle, a rotating body is turned by an electric motor, and a working machine such as a boom is driven by a hydraulic cylinder. The electric motor is driven, for example, by electric power stored in the power storage device. The hydraulic cylinder is driven by hydraulic oil discharged from a hydraulic pump. In such a hybrid type working vehicle, compared with a standard type working vehicle, the fuel consumption can be improved.

Japanese Patent Application Laid-Open No. 2010-285828 Japanese Patent No. 5044727

The working vehicle performs various operations using a working machine. Therefore, in order to improve workability, it is required to improve the operating speed of the working machine. For example, in an operation of mounting an object such as excavated soil on a dump truck, an operation of turning the vehicle and raising the boom is performed. In such combined operation, it is required to improve the rising speed of the boom in order to improve workability.

However, in the standard type work vehicle, the output of the hydraulic pump is distributed to the hydraulic motor for turning the revolving body and the hydraulic cylinder for driving the working machine. Therefore, since a part of the output of the hydraulic pump is used for driving the hydraulic motor, there is a limitation in improving the operating speed of the hydraulic cylinder.

An object of the present invention is to improve the fuel economy in the combined operation of the working vehicle and to improve the workability by increasing the operating speed of the working machine.

A working vehicle relating to an aspect of the present invention includes a vehicle body, an engine, a hydraulic pump, a working machine, a turning body, an electric motor, a combined operation detecting portion, a control mode selecting portion, An output calculation unit, and a pump output determination unit. The vehicle body has a traveling body and a slewing body rotatably supported with respect to the traveling body. The engine is mounted on the vehicle body. The hydraulic pump is driven by the engine. The working machine has a hydraulic actuator. The hydraulic actuator is driven by operating oil discharged (discharged) from the hydraulic pump. The electric motor turns the rotating body.

The combined operation detecting unit detects a combined operation state in which the hydraulic actuator and the electric motor are combined and operated. The control mode selection section selects the control mode from a plurality of control modes including a first control mode and a second control mode. The turning pump output calculating section calculates the turning pump output in which the output of the electric motor is converted into the output of the hydraulic pump. The reduction amount determining section determines the reduction amount of the output of the hydraulic pump in the combined operation based on the output of the swing pump.

The pump output determining section determines a value obtained by subtracting the reduction amount from the output of the hydraulic pump determined in accordance with the state of the combined operation in the first control mode as the output of the hydraulic pump in the combined operation. The pump output determining section increases the output of the hydraulic pump in the combined operation in the second control mode rather than the first control mode.

In the working vehicle according to this aspect, in the first control mode in the combined operation, the hydraulic actuator is driven by the reduced output determined by the reduction amount determined based on the output of the swing pump. Therefore, it is possible to improve the fuel consumption in the combined operation. The output for driving the hydraulic actuator corresponds to the output distributed to the hydraulic actuator in the standard type work vehicle. Therefore, it is possible to suppress the lowering of the operating speed of the hydraulic actuator as compared with the standard-type working vehicle.

Further, in the second control mode in the combined operation, the hydraulic actuator is driven with an output larger than that of the first control mode. Therefore, compared with the standard type work vehicle, it is possible to increase the operation speed of the working machine during the combined operation, thereby improving the workability.

In the second control mode, the pump output determining section may increase the output of the hydraulic pump in the combined operation by the amount corresponding to the reduced amount. In this case, in the second control mode, the hydraulic actuator can be driven with a large output as much as the output distributed to the hydraulic motor in the standard type work vehicle. As a result, the operation speed of the working machine during the combined operation can be further increased, and workability can be further improved.

In the second control mode, the pump output determining unit may increase the output of the hydraulic pump in the combined operation by the amount smaller than the reduced amount. In this case, it is possible to increase the operating speed of the working machine during the combined operation and to improve the fuel consumption, as compared with the first control mode.

The working vehicle may further include a discharge pressure detection unit and a motor output determination unit. The discharge pressure detection unit detects the discharge pressure of the hydraulic pump. The motor output determining section determines the output of the electric motor in the combined operation. In the first control mode, the motor output determining section may limit the output of the electric motor in accordance with the discharge pressure of the hydraulic pump. The motor output determining section does not have to limit the output of the electric motor in accordance with the discharge pressure of the hydraulic pump in the second control mode. In this case, in the first control mode, the electric motor can be driven with the output equivalent to the output distributed to the hydraulic motor in the standard type work vehicle. Further, in the second control mode, the electric motor can be driven with an output larger than the output distributed to the hydraulic motor in the standard type work vehicle. As a result, it is possible to further improve the workability in the combined operation.

The machine may have a boom. The hydraulic actuator may be a boom cylinder for driving the boom. In this case, in the first control mode, the fuel consumption can be improved at the time of so-called hoist swiveling in which the turning of the swivel body and the driving of the boom are performed in combination. Further, in the second control mode, the operation speed of the working machine is increased at the time of the hoist rotation, and the workability can be improved.

A control method according to another aspect of the present invention is a control method of a working vehicle. The control method according to this aspect includes the first to sixth steps. In the first step, the hybrid operating state in which the hydraulic actuator for the working machine and the electric motor for swiveling are combined and operated is detected. In the second step, the control mode is selected from a plurality of control modes including a first control mode and a second control mode. In the third step, the output of the electric motor is converted into the output of the hydraulic pump, and the output of the swing pump is calculated.

In the fourth step, the reduction amount of the output of the hydraulic pump in the combined operation is determined based on the output of the swing pump. In the fifth step, a value obtained by subtracting the reduction amount from the output of the hydraulic pump determined in accordance with the state of the combined operation in the first control mode is determined as the output of the hydraulic pump in the combined operation. In the sixth step, the output of the hydraulic pump in the combined operation is increased in the second control mode as compared with the first control mode.

In the control method of a working vehicle according to this aspect, in the first control mode in the combined operation, the hydraulic actuator is driven by the reduced output determined by the reduction amount determined based on the output of the swing pump. Therefore, it is possible to improve the fuel consumption in the combined operation. The output for driving the hydraulic actuator corresponds to the output distributed to the hydraulic actuator in the standard type work vehicle. Therefore, it is possible to suppress the lowering of the operating speed of the hydraulic actuator as compared with the standard-type working vehicle.

Further, in the second control mode in the combined operation, the hydraulic actuator is driven with an output larger than that of the first control mode. It is possible to increase the operation speed of the working machine in the combined operation as compared with the standard type work vehicle and thereby to improve the workability.

According to the present invention, in the working vehicle, it is possible to improve the fuel consumption in the combined operation and increase the operating speed of the working machine, thereby improving the workability.

1 is a perspective view of a working vehicle according to an embodiment.
2 is a schematic diagram showing a schematic configuration of a working vehicle.
3 is a view showing an engine output torque line and a pump absorption torque line.
4 is a diagram showing the output of the hydraulic pump in the first control mode and the second control mode in the combined operation.
5 is a block diagram showing a control system of the working vehicle.
6 is a flowchart showing the control of the hydraulic pump in the combined operation.
7 is a flowchart showing the control of the turning electric motor at the time of combined operation.
8 is a diagram showing the output of the hydraulic pump in the first control mode and the second control mode in the combined operation according to another embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a working vehicle according to an embodiment will be described with reference to the drawings. 1 is a perspective view of a working vehicle 100 according to an embodiment. In the present embodiment, the working vehicle 100 is a hydraulic excavator. The working vehicle 100 is provided with a vehicle body 1 and a working machine 4.

The vehicle body (1) has a traveling body (2) and a turning body (3). The traveling body 2 has a pair of traveling devices 2a and 2b. Each of the traveling devices 2a, 2b has a crawler track 2d, 2e. The traveling devices 2a and 2b drive the working vehicle 100 by driving the crawler tracks 2d and 2e.

The slewing body (3) is mounted on the traveling body (2). The slewing body (3) is provided so as to be pivotable with respect to the traveling body (2). The turning body 3 is turned by being driven by a turning electric motor 32 (see Fig. 2) to be described later. The cab 3 is provided with a cab 5. The swivel body (3) has an engine room (16). The engine room (16) is arranged behind the cabin (5). The engine room 16 accommodates devices such as an engine 21 and a hydraulic pump 25, which will be described later.

The working machine (4) is mounted on the revolving body (3). The work machine 4 has a boom 7, an arm 8, a work attachment 9, a boom cylinder 10, an arm cylinder 11, and an accessory cylinder 12. The proximal end of the boom (7) is rotatably connected to the revolving body (3). The distal end of the boom (7) is rotatably connected to the proximal end of the arm (8). The distal end of the arm 8 is rotatably connected to the workpiece 9.

The boom cylinder 10, the arm cylinder 11 and the accessory cylinder 12 are hydraulic actuators that are driven by operating fluid discharged from a hydraulic pump 25 described later. The boom cylinder 10 operates the boom 7. The arm cylinder 11 actuates the arm 8. The accessory cylinder (12) operates the workpiece (9). When the cylinders 10, 11, 12 are driven, the working machine 4 is driven. In the present embodiment, the workpiece fitting 9 is a bucket, but may be a crusher or other accessory such as a breaker.

2 is a schematic diagram showing a schematic configuration of the working vehicle 100. As shown in Fig. The engine 21 is, for example, a diesel engine. The output horsepower (horsepower) of the engine 21 is controlled by adjusting the amount of fuel injected into the cylinder of the engine 21. This adjustment is made by controlling the electronic governor 23 attached to the fuel injection pump 22 of the engine 21 by a command signal from the controller 40. [ As the governor 23, a governor of an all speed control system is generally used, and the engine rotation speed and the fuel injection amount are adjusted according to the load so that the engine rotation speed becomes the target rotation speed to be described later. In other words, the governor 23 increases or decreases the fuel injection amount such that the deviation between the target engine speed and the actual engine speed is eliminated.

The actual rotational speed of the engine 21 is detected by the engine rotational speed sensor 24. [ The engine rotation speed detected by the engine rotation speed sensor 24 is input to the controller 40 described later as a detection signal.

The output shaft of the engine 21 is connected to the drive shaft of the hydraulic pump 25. [ The hydraulic pump 25 is driven by rotating the output shaft of the engine 21. The hydraulic pump 25 is a variable displacement type hydraulic pump. The displacement of the swash plate 26 changes the capacity of the hydraulic pump 25.

The pump control valve 27 is operated by a command signal input from the controller 40 and controls the hydraulic pump 25 through the servo piston. The pump control valve 27 is controlled such that the product of the discharge pressure of the hydraulic pump 25 and the capacity of the hydraulic pump 25 is the command value of the command signal input from the controller 40 to the pump control valve 27 ) Of the swash plate 26 so that the pump absorption torque corresponding to the swash plate 26 is not exceeded. That is, the pump control valve 27 controls the output torque of the hydraulic pump 25 in accordance with the input command current value.

The hydraulic fluid discharged from the hydraulic pump 25 is supplied to the hydraulic actuators 10 to 12 through the working machine control valve 28. [ Specifically, the operating fluid is supplied to the boom cylinder 10, the arm cylinder 11, and the accessory cylinder 12. Thereby, the boom cylinder 10, the arm cylinder 11 and the accessory cylinder 12 are driven, respectively, and the boom 7, the arm 8 and the work accessories 9 are operated.

The discharge pressure of the hydraulic pump 25 is detected by the discharge pressure detector 39. [ The discharge pressure of the hydraulic pump 25 detected by the discharge pressure detector 39 is input to the controller 40 as a detection signal.

The working machine control valve 28 is a flow rate directional control valve having a plurality of control valves corresponding to the respective hydraulic actuators 10 to 12. The working machine control valve 28 controls the flow rate of hydraulic oil supplied to the hydraulic actuators 10 to 12.

The drive shaft of the generator electric motor 29 is connected to the output shaft of the engine 21. The power generation electric motor 29 performs the power generation action and the electric power action. The generator electric motor 29 is connected to the electric motor 32 via the inverter 33 and the capacitor 34 as a power storage device. Electric power is accumulated in the capacitor 34 by the generation electric motor 29 performing the power generation operation. The capacitor (34) supplies electric power to the swinging electric motor (32). When the generating electric motor 29 performs the electric action, the capacitor 34 supplies electric power to the electric generating electric motor 29. The swinging electric motor 32 is driven by the electric power supplied from the capacitor 34 to turn the swing body 3 described above. Furthermore, the present invention is not limited to a capacitor, and another power storage device such as a battery may be used.

The torque of the power generation electric motor 29 is controlled by the controller 40. [ A part of the output torque generated by the engine 21 is transmitted to the drive shaft of the generator electric motor 29 to absorb the torque of the engine 21 to generate electric power .

The AC power generated by the generator electric motor 29 is converted into DC power by the inverter 33 and supplied to the capacitor 34. The direct current electric power stored in the capacitor 34 is converted into the alternating electric power by the inverter 33 and supplied to the electric power generating electric motor 29 when the electric power generation electric motor 29 is controlled to perform the electric action. Thereby, the drive shaft of the generator electric motor 29 is rotationally driven, and torque is generated by the generator electric motor 29. This torque is transmitted from the drive shaft of the generator electric motor 29 to the output shaft of the engine 21 and added to the output torque of the engine 21. [ (The amount of absorption torque) and the amount of electric power (amount of assist torque generated) of the electric generator motor 29 are controlled in accordance with the command signal from the controller 40. [

The inverter 33 converts the generated electric power or the electric power stored in the capacitor 34 when the electric generating motor 29 generates electric power to a desired voltage, frequency, and phase number suitable for the electric motor 32 ; number of phases), and supplies the electric power to the turning electric motor 32. When the swing motion of the swing body 3 is decelerated or braked, the kinetic energy of the swing body 3 is converted into electric energy. This electric energy is stored as a regenerative electric power in the capacitor 34 or supplied as electric power for the electric action of the electric power generation motor 29.

In the cab 5, operating devices 51 to 53 and a display input device 43 are provided. The operating devices 51 to 53 have a first operating device 51, a second operating device 52, and a target rotational speed setting device 53. [

The first operating device 51 is operated by an operator to operate the turning body 3. The first operating device 51 has, for example, an operating member such as a lever. An operation signal indicating the operation direction and the operation amount of the first operation device 51 is input to the controller 40. [ In other words, the turning operation signal indicating the right turning operation amount or the left turning operation amount is inputted to the controller 40 in accordance with the operation direction and the operation amount with respect to the neutral position of the first operation device 51.

The controller 40 controls the electric power supplied from the capacitor 34 to the swinging electric motor 32 in accordance with the operation amount of the first operating device 51. [ Thereby, the turning body 3 turns at a speed corresponding to the operation amount of the first operating device 51. [ Further, the turning body 3 turns in the direction along the operating direction of the first operating device 51. [

The first operating device 51 may also be used as an operating device of the arm 8 along the operating direction. For example, the operation in the left-right direction and the operation in the front-rear direction of the first operating device 51 may be allotted to the operation of the arm 8 and the operation of the slewing body 3. [ In this case, the above-described working machine control valve 28 changes the opening area of the control valve for controlling the arm cylinder 11 in accordance with the operation amount of the first operating device 51. [ Thereby, the arm 8 is operated at a speed corresponding to the operation amount of the first operating device 51. The arm cylinder 11 is expanded and contracted along the operating direction of the first operating device 51. [

The second operating device 52 is operated by an operator to operate the boom 7. [ The second operating device 52 has, for example, an operating member such as a lever. An operation signal indicating the operation direction and the operation amount of the second operation device 52 is input to the controller 40. [ That is, the boom operation signal indicating the boom up operation amount or the boom down operation amount is input to the controller 40 in accordance with the operation direction and the operation amount to the neutral position of the second operation device 52.

The working machine control valve 28 changes the opening area of the control valve for controlling the boom cylinder 10 in accordance with the operation amount of the second operating device 52. As a result, the boom 7 is operated at a speed corresponding to the operation amount of the second operating device 52. Further, the boom cylinder 10 is expanded and contracted along the operating direction of the second operating device 52.

The second operating device 52 may also be used as an operating device of the work piece 9 along the operating direction. For example, the operation in the left-right direction and the operation in the back-and-forth direction of the second operation device 52 may be allotted to the operation of the boom 7 and the operation of the workpiece 9. In this case, the working machine control valve 28 changes the opening area of the control valve for controlling the accessory cylinder 12 in accordance with the operation amount of the second operating device 52. Thereby, the work attachment 9 operates at a speed corresponding to the operation amount of the second operating device 52. [ Further, the accessory cylinder 12 is expanded and contracted along the operating direction of the second operating device 52.

The target rotational speed setting device 53 is a device for setting the target rotational speed of the engine 21. [ The target rotational speed setting device 53 has, for example, an operating member such as a dial. The operator can manually set the target rotation speed of the engine 21 by operating the target rotation speed setting device 53. [ The operation contents of the target rotation speed setting device 53 are input to the controller 40 as an operation signal.

The display input device 43 functions as a display device for displaying the information of the working vehicle 100, such as the engine rotation speed. The display input device 43 also has a touch panel type monitor and functions as an input device operated by an operator.

The controller 40 is realized by a computer having a storage unit 42 such as a RAM and a ROM and an operation unit 41 such as a CPU. The controller 40 is programmed to control the engine 21 and the hydraulic pump 25. The controller 40 may be implemented by a plurality of computers.

The controller 40 controls the engine 21 based on the engine output torque line indicated by P1 or E1 in Fig. The engine output torque line represents the torque upper limit value that the engine 21 can output in accordance with the rotation speed. That is, the engine output torque line defines the relationship between the engine rotation speed and the maximum value of the output torque of the engine 21. [ The governor 23 controls the output of the engine 21 so that the output torque of the engine 21 does not exceed the engine output torque line. The engine output torque line is stored in the storage section 42 of the controller 40.

The controller 40 sends an instruction signal to the governor 23 so that the engine rotational speed becomes the set target rotational speed. FH in Fig. 3 represents the maximum speed regulation line when the target rotation speed is the maximum target rotation speed NH. Fl in FIG. 3 shows a regulation line when the target rotation speed is N1 smaller than NH. Thus, the controller 40 changes the engine output torque line in accordance with the set target rotation speed.

The controller 40 calculates the target absorption torque of the hydraulic pump 25 in accordance with the target rotation speed of the engine 21. [ The target absorption torque is set so that the output horsepower of the engine 21 and the absorption horsepower of the hydraulic pump 25 are balanced. The controller 40 calculates the target absorption torque based on the pump absorption torque line indicated by Lp in Fig. The pump absorption torque line defines the relationship between the engine rotation speed and the absorption torque of the hydraulic pump 25 and is stored in the storage unit 42 of the controller 40. [

Further, the controller 40 selects the engine output torque line in accordance with the set working mode. The operation mode is set by the display input device 43. There are P mode and E mode as working modes.

The P mode is a work mode in which the output torque of the engine 21 is large and workability is excellent. In the P mode, the first engine output torque line P1 shown in Fig. 3 is selected. The first engine output torque line P1 corresponds to, for example, the rated or maximum power output of the engine 21.

The E mode is a working mode in which the output torque of the engine 21 is smaller than the P mode and the fuel consumption is excellent. In the E mode, the second engine output torque line E1 shown in Fig. 3 is selected. In the second engine output torque line E1, the output torque of the engine 21 becomes smaller than the first engine output torque line P1.

In the working vehicle 100 according to the present embodiment, the operator can select a plurality of control modes for the P mode described above. The plurality of control modes have a first control mode and a second control mode. In the second control mode, the controller 40 controls the engine 21 by the first engine output torque line P1. In the first control mode, the output of the hydraulic pump 25 is reduced as described later, and the output torque of the engine is reduced accordingly. That is, in the second control mode, the output of the hydraulic pump 25 is increased more than the first control mode.

4 is a diagram showing the output of the hydraulic pump 25 in the first control mode and the second control mode in the combined operation. Incidentally, in the present embodiment, the combined operation means a combined operation of raising the boom and turning, and it is assumed that the operation of the other hydraulic actuator is not performed.

In Fig. 4, Tmax is the maximum output of the hydraulic pump 25 determined by the above-described pump absorption torque. 4, in the first control mode, the output of the hydraulic pump 25 is reduced to a value T1 smaller than the maximum output Tmax. The reduction amount dT is determined based on the output of the swinging electric motor 32 and the output of the hydraulic pump 25 on the basis of the swing pump output. In the first control mode, the boom cylinder 10 is driven by the output T1 of the hydraulic pump 25.

In the second control mode, the output of the hydraulic pump 25, such as the first control mode, is not reduced, and the maximum output Tmax becomes the output of the hydraulic pump 25. [ That is, in the second control mode, the output of the hydraulic pump 25 during the combined operation is increased by the amount equivalent to the reduced amount dT, as compared with the first control mode. In the second control mode, the boom cylinder 10 is driven by the maximum output Tmax. Specifically, in the second control mode, the output of the hydraulic pump 25 is determined in accordance with the amount of operation of the first operating device 51 and the second operating device 52. [ The maximum output Tmax is the maximum value of the output of the hydraulic pump 25 determined according to the operation amount of the first operating device 51 and the second operating device 52. [

The maximum output Tmax is the maximum value of the output of the hydraulic pump 25 when the swing electric motor 32 is not operated and only the boom cylinder 10 is operated. Hereinafter, the processing in the first control mode and the second control mode in the combined operation will be described in detail.

5 is a block diagram showing a control system of the working vehicle 100. As shown in Fig. 5, the calculation section 41 of the controller 40 includes a complex operation detection section 44, a control mode selection section 45, a swirl pump output calculation section 46, a reduction amount determination section 47 A pump output determination unit 48, and a motor output determination unit 49.

Fig. 6 is a flowchart showing the control of the hydraulic pump 25 in the combined operation. As shown in Fig. 6, in step S1, the compound operation detecting section 44 detects whether or not the boom cylinder 10 and the swinging electric motor 32 are operated in combination. More specifically, the combined operation detecting section 44 detects whether or not the boom raising operation and the swing operation are performed in combination. The combined operation detecting unit 44 determines the presence or absence of the combined operation by the detection signals from the first operating device 51 and the second operating device 52. [ When the boom raising operation and the turning operation are performed in combination, the process proceeds to step S2.

In step S2, it is determined whether or not the first control mode is selected. The operator can set either the first control mode or the second control mode by operating the display input device 43. [ The control mode selection unit 45 receives a selection signal indicating the selected control mode from the display input device 43 and sets the selected control mode as a control mode at the time of the complex operation. When the first control mode is selected in step S2, the process proceeds to step S3. When the first control mode is not selected in step S2, that is, when the second control mode is selected, the flow proceeds to step S6.

In step S3, the above-described reduction amount dT is calculated. The reduced amount dT is represented by the following equation (1).

[Equation 1]

alpha is a predetermined gain. In the first control mode, a value of 1, or a value near 1, is set. Ls is the orbiting pump output. The turning pump output calculating section 46 calculates the output of the turning electric motor 32 by multiplying the output torque of the turning electric motor 32 by the rotating speed of the turning electric motor 32 and outputs it to the hydraulic pump 25 To thereby calculate the turning pump output Ls. The turning pump output Ls is expressed by the following equation (2).

[Equation 2]

Nm is the rotational speed of the swivel electric motor 32. The rotational speed Nm of the swivel electric motor 32 is detected by the motor rotational speed detecting portion 54. [ Tm is the output torque of the swing electric motor 32. [ The output torque Tm of the turning electric motor 32 is detected by the motor torque detecting section 55. [ ρ is the efficiency with which the hydraulic pressure loss is added, and a predetermined value is set.

The amount-of-decrease determining section 47 calculates the reduction amount dT of the output of the hydraulic pump 25 in the combined operation from the above-described swirl pump output Ls and Equation 1. [

Next, in step S4, the pump output determining unit 48 calculates the output Tp of the hydraulic pump 25 in the combined operation. The output Tp of the hydraulic pump 25 in the combined operation is calculated by the following equation (3).

[Equation 3]

That is, in the first control mode, the pump output determining unit 48 determines a value obtained by subtracting the reduction amount dT from the maximum output Tmax of the hydraulic pump 25 as the output Tp of the hydraulic pump 25 in the combined operation . In step S5, the controller 40 outputs a command signal corresponding to the output Tp of the hydraulic pump 25 to the pump control valve 27. [ As described above, in the first control mode, the output Tp of the hydraulic pump 25 is a value T1 smaller than the maximum output Tmax, as shown in Fig.

In step S2, when the second control mode is selected, the process proceeds to step S6. In step S6, the reduction amount dT is set to zero. Specifically, in the second control mode, the above-described gain? Is set to zero, so that the reduction amount dT becomes zero.

Then, in the step S4, the output Tp of the hydraulic pump 25 at the time of the combined operation becomes the maximum output Tmax in the second control mode from the above-mentioned equation (3). That is, in the second control mode, the pump output determining unit 48 increases the output of the hydraulic pump 25 in the combined operation by the amount equivalent to the reduced amount dT.

Then, in step S5, the controller 40 outputs a command signal corresponding to the output Tp of the hydraulic pump 25 to the pump control valve 27. [ As described above, in the second control mode, the output Tp of the hydraulic pump 25 becomes the maximum output Tmax as shown in Fig.

Next, control of the swing electric motor 32 in the first control mode and the second control mode will be described. 7 is a flowchart showing the control of the swing electric motor 32 in the combined operation. In Fig. 7, steps S11 and S12 are the same as steps S1 and S2 described above, respectively, and a description thereof will be omitted.

When the first control mode is selected in step S12, the output of the swing electric motor 32 is limited in steps S13 to S15. More specifically, in step S13, the discharge pressure of the hydraulic pump 25 is detected. The discharge pressure of the hydraulic pump 25 is detected by the discharge pressure detector 39. [

In step S14, the upper limit Tm1 of the motor output is calculated. Here, the motor output determining unit 49 determines the upper limit Tm1 of the motor output in accordance with the discharge pressure of the hydraulic pump 25. For example, the motor output determining unit 49 decreases the upper limit Tm1 of the motor output as the discharge pressure of the hydraulic pump 25 becomes smaller.

Next, in step S15, the motor output command value is determined. Here, the motor output determining section 49 determines, as the motor output command value, the smaller one of the motor output Tm2 determined by the manipulated variable of the first manipulating device 51 and the upper limit Tm1 of the motor output described above. That is, in the first control mode, the motor output determining unit 49 limits the output of the swing electric motor 32 to the upper limit Tm1 of the motor output in accordance with the discharge pressure of the hydraulic pump 25.

In step S16, the controller 40 outputs to the inverter 33 a command signal corresponding to the motor output command value. In a standard-type work vehicle, the output of the hydraulic pump 25, which is distributed for turning by the hydraulic motor, is determined according to the discharge pressure of the hydraulic pump 25. Therefore, by determining the upper limit Tm1 of the motor output in the first control mode as described above, the output of the hydraulic pump 25 for turning in the standard work vehicle, as indicated by a broken line in Fig. 4, The output of the swivel electric motor 32 equivalent to the output of the swivel electric motor 32 can be obtained.

In step S12, when the second control mode is selected, the output of the swing electric motor 32 is not limited as in steps S13 to S15. Therefore, in step 17, the motor output determining section 49 determines the motor output Tm2 determined in accordance with the operation amount of the first operating device 51 as the motor output command value.

In step S16, the controller 40 outputs to the inverter 33 a command signal corresponding to the motor output command value. Thus, as shown by the broken line in Fig. 4, in the second control mode, the output of the swinging electric motor 32 can be obtained in excess of the output of the swing electric motor 32 in the first control mode.

The motor output determining unit 49 does not limit the output of the swinging electric motor 32 according to the discharge pressure of the hydraulic pump 25 in the second control mode, But the output of the swinging electric motor 32 is limited.

In the working vehicle 100 according to the present embodiment described above, in the first control mode at the time of the combined operation, the boom cylinder 10 is driven with the reduced output determined by the reduction amount determined based on the output of the swing pump. Therefore, it is possible to improve the fuel consumption in the combined operation. The reduced output corresponds to an output distributed to the boom cylinder drive in a standard type work vehicle. Therefore, it is possible to suppress the lowering of the operating speed of the boom cylinder 10 as compared with the standard type work vehicle.

In the second control mode during the combined operation, the same output as the first control mode is not reduced, and the boom cylinder 10 is driven at the maximum output Tmax. Therefore, the operation speed of the boom cylinder 10 during combined operation can be increased, and workability can be improved.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

The pump output determination unit 48 may increase the output of the hydraulic pump 25 in the combined operation by the amount that is smaller than the reduced amount dT in the second control mode. That is, in the second control mode, the gain? Of Equation 1 may be set to a value larger than 0 and smaller than 1. In this case, as shown in Fig. 8, the output Tp of the hydraulic pump 25 used for driving the boom cylinder 10 in the second control mode is a value between T1 and Tmax.

The control mode is not limited to two of the first control mode and the second control mode, but may be three or more. For example, in the third control mode, the reduction amount dT may be a value between the first control mode and the second control mode.

In the above-described embodiment, the present invention is applied to the combined operation of the boom raising and the turning, but the present invention may be applied to the combined operation of the operation of the working machine 4 other than the boom raising and the turning.

According to the present invention, in the working vehicle, it is possible to improve the fuel consumption in the combined operation and increase the operating speed of the working machine, thereby improving the workability.

Claims (6)

1. A vehicle body comprising: a traveling body; and a swivel body supported so as to be capable of turning on the traveling body;
An engine mounted on the vehicle body;
A hydraulic pump driven by the engine;
A working machine having a hydraulic actuator driven by hydraulic oil discharged (discharged) from the hydraulic pump;
An electric motor for turning the slewing body;
A combined operation detecting unit for detecting a combined operation state in which the hydraulic actuator and the electric motor are combined and operated;
A control mode selecting unit for selecting a control mode from a plurality of control modes including a first control mode and a second control mode;
A swirl pump output calculation unit for calculating a swirl pump output obtained by converting an output of the electric motor into an output of the hydraulic pump;
A reduction amount determining unit that determines a reduction amount of the output of the hydraulic pump in the combined operation based on the output of the swing pump; And
Determines a value obtained by subtracting the reduction amount from the maximum output of the hydraulic pump determined in accordance with the state of the combined operation in the first control mode as the output of the hydraulic pump in the combined operation, A pump output determining unit that increases the output of the hydraulic pump in the combined operation, as compared with the first control mode;
. The method according to claim 1,
Wherein the pump output determining section increases the output of the hydraulic pump in the combined operation by the amount equivalent to the reduced amount in the second control mode. The method according to claim 1,
The pump output determining section increases the output of the hydraulic pump in the combined operation by the amount smaller than the reduced amount in the second control mode. 4. The method according to any one of claims 1 to 3,
A discharge pressure detector for detecting a discharge pressure of the hydraulic pump;
A motor output determining unit for determining an output of the electric motor in the combined operation;
Further comprising:
Wherein the motor output determining unit limits the output of the electric motor in accordance with the discharge pressure of the hydraulic pump in the first control mode and controls the output of the electric motor in accordance with the discharge pressure of the hydraulic pump in the second control mode, Of the working vehicle. The method according to claim 1,
The work machine has a boom,
Wherein the hydraulic actuator is a boom cylinder for driving the boom. A hybrid operation state in which a hydraulic actuator for a work machine and an electric motor for turning are combined and operated;
Receiving a selection signal indicating a control mode selected from a plurality of control modes including a first control mode and a second control mode;
Calculating an output of the electric motor as the output of the hydraulic pump;
Determining a reduction amount of the output of the hydraulic pump in the combined operation based on the output of the swing pump;
Determining a value obtained by subtracting the reduction amount from a maximum output of the hydraulic pump determined in accordance with the state of the combined operation in the first control mode as an output of the hydraulic pump in the combined operation; And
Outputting a command signal of the hydraulic pump so as to increase the output of the hydraulic pump in the combined operation, in the second control mode, from the first control mode;
And a control unit for controlling the operation of the work vehicle.

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