JP2014009078A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle which quickly performs working through a work device after an engine is stopped by an idling stop function in a work mode and downsizes the device.SOLUTION: If an engine 41a starts from the state that the engine 41a is stopped by an idling stop function in a work mode, a hydraulic pump 31 is driven by power of a motor generator 41b, and then power of the engine 41a is transmitted to the hydraulic pump 31. On the other hand, if the engine 41a starts from the state that the engine 41a is stopped by the idling stop function in a travel mode, the engine 41a is started up by power of the motor generator 41b connected to the engine 41a.

Description

  The present invention relates to a work vehicle including a work device that is driven by power of one or both of an engine and an electric motor.

  A conventional work vehicle includes a hybrid power source including a vehicle traveling engine, an electric motor, and a hydraulic pump for driving an engine and a working device that can be driven by at least the power of the electric motor. Are known (for example, see Patent Document 1).

  Further, as a conventional work vehicle, a vehicle having an idling stop function for stopping the engine when a predetermined condition is satisfied and restarting the engine by a predetermined operation such as an accelerator pedal operation is known. ing.

JP 2000-226183 A

  In a work vehicle equipped with the hybrid power source, the driving power of the engine is mainly driven by the engine power, and the power of the electric motor is added to the engine power as an assist output. For this reason, when the idling stop function is applied to a work vehicle having a hybrid power source, the work is resumed from a state in which the engine is stopped by the idling stop function in a work mode in which work is performed by the work device. Sometimes, the hydraulic pump is started by starting the engine. In this case, the work device requires time until the engine is started, and it takes time to increase the pressure in the hydraulic circuit to which the hydraulic pump and the actuator are connected to a workable pressure. It takes a long time until it becomes possible. In particular, in a mobile crane among work vehicles, it takes a long time to increase the pressure in the hydraulic circuit that drives the crane device as the work device to a workable pressure.

  Further, the work vehicle has a large output required for traveling relative to the output required for driving the work device, and is large in order to install an electric motor having a large output capable of running the work vehicle and a large capacity battery. Installation space is required.

  An object of the present invention is to provide a work vehicle capable of performing work by the work device immediately after the engine is stopped by the idling stop function in the work mode and reducing the size of the device. .

  In order to achieve the above object, the present invention provides a work vehicle in which a working device for performing a predetermined work is provided on a moving traveling body, and the power used for driving the traveling body and driving the working device is provided. An outputable engine, an electric motor that can be connected to the output shaft of the engine, and that can output the power used to drive the traveling body and drive the work device, and the work device is driven by the power of one or both of the engine and the motor A hydraulic pump for generating hydraulic pressure, an engine stop means for stopping the engine when a predetermined condition is satisfied in the working mode for performing work by the working device and the traveling mode for traveling, and the engine in the working mode. When starting the engine from the stop state of the engine at the stop means, the drive of the hydraulic pump is started by the power of the electric motor. After that, when the engine power is transmitted to the hydraulic pump and the engine is started from the engine stop state in the engine stop means in the traveling mode, the engine stop is released to start the engine by the power of the electric motor connected to the engine. Means.

  Thus, since the hydraulic pump is driven by the power of the electric motor before starting the engine from the engine stopped state in the engine stop means in the work mode, the hydraulic pressure in the hydraulic circuit is increased in advance when the engine is started. Has been. In addition, since the engine is started from the engine stop state by the engine stop means in the traveling mode by the electric motor, the vehicle can be rapidly driven by the output of the engine, and the electric motor for starting the engine is not required. .

  According to the present invention, when the engine is started from a state where the engine is stopped in the work mode, the hydraulic pressure in the hydraulic circuit can be increased, so that work efficiency can be improved. In addition, when the engine is started in the travel mode, the vehicle can be quickly driven by the output of the engine, and since a dedicated electric motor for starting the engine is not required, the device can be downsized. Is possible.

It is a side view of the mobile crane which shows one Embodiment of this invention. It is a schematic block diagram which shows the power clerk and control system of a mobile crane apparatus. It is a flowchart which shows a driving | running | working idling stop control process. It is a flowchart which shows a work idling stop control process.

  1 to 4 show an embodiment of the present invention.

  As shown in FIG. 1, a mobile crane 1 as a work vehicle according to the present invention includes a traveling vehicle 10 and a crane device 20.

  The vehicle 10 has wheels 11 and travels using the engine 41a or the engine 41a and a motor generator 41b described later as a power source. Further, on both the left and right sides of the front side and the rear side of the vehicle 10, there are provided outriggers 12 for preventing the vehicle 10 from overturning during crane operation and for stably supporting the vehicle 10. The outrigger 12 can move outward in the width direction, and can extend downward by a hydraulic jack cylinder 13 (FIG. 2). The outrigger 12 stably supports the vehicle 10 with respect to the ground by grounding the lower end.

  The crane apparatus 20 includes a swivel base 21 that is turnable on a horizontal plane at a substantially central portion in the front-rear direction of the vehicle 10, a boom 22 that is provided so as to be able to rise and fall with respect to the swivel base 21, and is extendable. The wire rope 23 suspended from the distal end side of the boom 22, the winch 24 for winding or unwinding the wire rope 23, and the front side of the swivel base 21 are related to the traveling of the vehicle 10 and the work by the crane device 20. And a cabin 25 for operation.

  The swivel base 21 is provided so as to be turnable with respect to the vehicle 10 via a ball bearing type or roller bearing type turning circle 21a, and is turned by a hydraulic turning motor 21b (FIG. 2).

  The boom 22 includes a plurality of boom members 22a, 22b, 22c, and 22d. The boom members 22b, 22c, and 22d that are adjacent to the distal end side inside the boom members 22a, 22b, and 22c excluding the boom member 22d on the most advanced side. Is configured to be telescopic. The base end portion of the most proximal end boom member 22 a is swingably connected to the bracket 21 c of the swivel base 21. A hydraulic hoisting cylinder 22e is connected between the boom member 22a and the bracket 21c, and the boom 22 is hoisted by an expansion and contraction operation of the hoisting cylinder 22e. A hydraulic telescopic cylinder 22f (FIG. 2) is provided inside the boom member 22a on the most proximal end side, and the boom 22 is expanded and contracted by the expansion and contraction of the expansion cylinder 22f.

  The wire rope 23 is provided with a hook block 23 a on the distal end side, and the hook block 23 a is suspended from the distal end portion of the boom 22. A suspended load can be locked to the hook block 23 a, and the suspended load locked to the hook block 23 a is suspended from the tip of the boom 22.

  The winch 24 has a drum 24a around which the wire rope 23 is wound, and the drum 24a is configured to be rotatable forward and backward by a hydraulic winch motor 24b (FIG. 2).

  The cabin 25 is provided on the side of the bracket 21 c on the turntable 21 and turns together with the turntable 21.

  Actuators such as each jack cylinder 13, turning motor 21 b, hoisting cylinder 22 e, telescopic cylinder 22 f and winch motor 24 b operate by supplying or discharging hydraulic oil. The hydraulic oil that operates each actuator is supplied by a hydraulic pressure supply device 30 shown in FIG.

  As shown in FIG. 2, the hydraulic pressure supply device 30 includes a hydraulic pump 31 for generating hydraulic pressure, a control valve unit 32 for controlling the flow of hydraulic oil discharged from the hydraulic pump 31, and a hydraulic pump 31. A hydraulic oil circuit 33 for operating each actuator by supplying the discharged hydraulic oil via the control valve unit 32;

  As shown in FIG. 2, the hydraulic pump 31 is driven by power extracted from a power device 40 for supplying power for driving the vehicle 10 and power for driving the crane device 20.

  The control valve unit 32 has a plurality of control valves corresponding to each actuator. Each control valve is operated by an operation unit 32a such as an operation lever or an operation pedal, the flow path of the hydraulic oil is switched according to the operation direction of the operation unit 32a, and the flow rate of the hydraulic oil according to the operation amount of the operation unit 32a. Can be adjusted. Each control valve has switching means such as a solenoid and can be operated by a signal from an overload prevention device described later.

  The power unit 40 includes a power source unit 41 for generating power, a torque converter 42 as a drive mechanism for amplifying torque and transmitting the power output from the power source unit 41 to the wheel 11 side, A transmission 43 serving as a drive mechanism for changing the rotational speed and torque of the power output from the torque converter 42 and a propeller shaft 44 serving as a drive mechanism for transmitting the power output from the transmission 43 to the wheels 11 are provided. An electric retarder 45.

  The power source unit 41 functions as an electric motor mainly by an engine 41a that is a power source for traveling the vehicle and the supplied electric power, and also functions as a generator by the power of the engine 41a or during deceleration during traveling. The motor generator 41b and the battery 41c capable of supplying power when the motor generator 41b functions as an electric motor while controlling the power generated by the motor generator 41b, the output of the battery 41c, A motor generator drive control unit 41d for controlling the operation and a clutch 41e capable of switching the connection and release of the connection between the output shaft of the engine 41a and the input / output shaft of the motor generator 41b.

  The motor generator 41b is provided between the engine 41a and the torque converter 42. The power of the engine 41a is transmitted to the torque converter 42 via the input / output shaft of the motor generator 41b by connecting the output shaft of the engine 41a and the input / output shaft of the motor generator 41b by the clutch 41e.

  The motor generator drive control unit 41d includes an inverter, a boost converter, a motor control unit, a generator control unit, and the like. The motor generator drive control unit 41d controls the output of the battery 41c to supply electric power to the motor generator 41b, or functions the motor generator 41b to a generator or an electric motor in accordance with a signal from an overload prevention device to be described later. Switch. The motor generator drive control unit 41d is provided with a power cable 41f that can be connected to an external power supply. The motor generator drive control unit 41d can switch the power source to the battery 41c or an external power source when the motor generator 41b functions as an electric motor.

  The torque converter 42 has a pump impeller provided on the input shaft, a turbine liner provided on the output shaft, and a stator fixed between the pump impeller and the turbine liner, and is input to the input shaft. The power is output from the output shaft after the torque is amplified via oil. A PTO (power take-off) mechanism 46 capable of taking out the power transmitted to the transmission 43 is provided on the output side of the torque converter 42, and the hydraulic pump 31 can be connected via the PTO mechanism 46. The PTO mechanism 46 is provided on the output side of the torque converter 42 as long as the output shaft of the engine 41a with respect to the hydraulic pump 31 and the input / output shaft of the torque converter 42 can be switched. It does not have to be.

  In the mobile crane 1, the load acting on the tip of the boom 22 is rated according to the working conditions such as the overhang width of the outrigger 12, the swivel angle of the swivel 21, the undulation angle of the boom 22, and the extension length. An overload prevention device 50 is provided to prevent a so-called overload state, which is a state exceeding the load.

  The overload prevention device 50 has a controller including a CPU, a ROM, a RAM, and the like. When the controller receives an input signal from a device connected to the input side, the CPU reads a program stored in the ROM based on the input signal, and stores a state detected by the input signal in the RAM. An output signal is transmitted to a device connected to the output side.

The overload prevention device 50 includes a control valve unit 32, a power source unit 41, an operation input unit 51 for performing various settings related to crane work by a user, and a flow rate of hydraulic oil discharged from the hydraulic pump 31. A flow rate detector 52 for detecting and a pressure detector 53 for detecting the pressure on the discharge side of the hydraulic pump 31 are connected.
The overload prevention device 50 receives a signal related to the rotational speed of the engine 41a, a signal related to the discharge amount of hydraulic oil from the hydraulic pump 31, and a signal related to the pressure on the discharge side of the hydraulic pump 31.
The overload prevention device 50 operates the motor generator 41b based on the input signal relating to the rotational speed of the engine 41a, signal relating to the hydraulic oil discharge flow rate of the hydraulic pump 31, and signal relating to the pressure on the discharge side of the hydraulic pump 31. A control signal for controlling the signal is output.

  In the mobile crane 1 as the work vehicle configured as described above, the power of the engine 41 a is mainly transmitted to the propeller shaft 44 in the travel mode that is the travel time of the vehicle 10. Further, when the vehicle 10 is traveling, when a large output is required, such as when the vehicle speed is increased or when going up a slope, the power of the motor generator 41b is transmitted to the propeller shaft 44 as an assist output by driving the motor generator 41b. Is done. At that time, the PTO mechanism 46 is in a state in which the connection between the hydraulic pump 31 and the torque converter 42 is released. The engine 41a is started by the power of the motor generator 41b. Further, when the vehicle 10 is decelerated during traveling, the retarder 45 generates electric power, and the generated electric power is charged in the battery 41c.

  Moreover, in the crane work by the crane apparatus 20, as a mode for driving the hydraulic pump 31, an ultra-low noise work mode in which the hydraulic pump 31 is driven mainly by the power of the motor generator 41b in order of high silence, mainly at a predetermined rotational speed. One of the low noise work mode in which the hydraulic pump 31 is driven by the power of the engine 41a and the medium noise work mode in which the hydraulic pump 31 is driven mainly by the power of the engine 41a at an arbitrary rotational speed is It can be selected by operating the operation input unit 51.

  The controller of the overload prevention device 50 causes the engine 41a to operate by the idling stop function when the engine stop condition is satisfied, for example, when the accelerator operation is not performed for a predetermined time or more during traveling by the vehicle 10 or crane operation. Can be stopped. Further, the controller of the overload prevention device 50 starts the engine 41a when the engine start condition is satisfied, for example, when an accelerator operation is detected in a state where the engine 41a is stopped by the idling stop function. Is possible.

  The idling stop function is to stop the engine 41a while maintaining the function of the overload prevention device 50 when the engine stop condition is satisfied.

  In the traveling mode, the controller of the overload prevention device 50 performs a traveling idling stop control process. The operation of the controller of the overload prevention device 50 at this time will be described using the flowchart of FIG.

(Step S31)
In step S31, the CPU determines whether or not the travel mode is set. If it is determined that the travel mode is selected, the process proceeds to step S32. If the travel mode is not determined, the travel idle stop control process is terminated.

(Step S32)
If it is determined in step S31 that the travel mode is set, the CPU determines in step S32 whether an engine stop condition is satisfied. When it is determined that the engine stop condition is satisfied, the process proceeds to step S33, and when it is not determined that the engine stop condition is satisfied, the traveling idling stop control process is ended.

(Step S33)
When it is determined in step S32 that the engine stop condition is satisfied, in step S33, the CPU stops the engine 41a and moves the process to step S34.

(Step S34)
In step S34, the CPU determines whether or not an engine start condition is satisfied. If it is determined that the engine start condition is satisfied, the process proceeds to step S35. If it is not determined that the engine start condition is satisfied, the process of step S34 is repeated.

(Step S35)
When it is determined in step S34 that the engine start condition is satisfied, in step S35, the CPU drives the motor generator 41b, starts the engine with the power of the motor generator 41b, and ends the traveling idling stop control process.

  Further, in the low noise work mode or the medium noise work mode, the controller of the overload prevention device 50 performs a work idling stop control process. The operation of the controller of the overload prevention device 50 at this time will be described using the flowchart of FIG.

(Step S41)
In step S41, the CPU determines whether the low noise work mode or the medium noise work mode is set. If it is determined that the low noise work mode or the medium noise work mode is selected, the process proceeds to step S42, and if it is not determined that the low noise work mode or the medium noise work mode is selected, the work idling stop control process is ended. To do.

(Step S42)
If it is determined in step S41 that the operation mode is the low noise operation mode or the medium noise operation mode, the CPU determines in step S42 whether or not an engine stop condition is satisfied. If it is determined that the engine stop condition is satisfied, the process proceeds to step S43. If it is not determined that the engine stop condition is satisfied, the work idling stop control process is ended.

(Step S43)
When it is determined in step S42 that the engine stop condition is satisfied, in step S43, the CPU stops the engine 41a and moves the process to step S44.

(Step S44)
In step S44, the CPU determines whether or not an engine start condition is satisfied. If it is determined that the engine start condition is satisfied, the process proceeds to step S45. If it is not determined that the engine start condition is satisfied, the process of step S44 is repeated.

(Step S45)
When it is determined in step S44 that the engine start condition is satisfied, in step S45, the CPU releases the connection between the engine 41a and the motor generator 41b by the clutch 41e (OFF), and proceeds to step S46.

(Step S46)
In step S46, the CPU drives the motor generator 41b to drive the hydraulic pump 31, and the process proceeds to step S47.

(Step S47)
In step S47, the CPU connects the engine 41a and the motor generator 41b by the clutch 41e (ON), and moves the process to step S48.

(Step S48)
In step S48, the CPU starts the engine 41a with the power of the motor generator 41b and ends the work idling stop control process.

  Thus, according to the work vehicle of the present embodiment, when the engine 41a is started from the stop state of the engine 41a with the idling stop function in the work mode, the hydraulic pump 31 is driven by the power of the motor generator 41b. After starting, the power of the engine 41a is transmitted to the hydraulic pump 31, and when the engine 41a is started from the stop state of the engine 41a by the idling stop function in the traveling mode, the motor generator 41b connected to the engine 41a The engine 41a is started by power. As a result, when the engine 41a is started from the state where the engine 41a is stopped by the idling stop function in the work mode, the hydraulic pressure in the hydraulic oil circuit 33 can be increased, so that the work efficiency is improved. Is possible. In addition, when the engine 41a is started in the traveling mode, the vehicle can be quickly driven by the output of the engine 41a, and a dedicated electric motor for starting the engine 41a is not required, so that the apparatus can be downsized. Can be achieved.

  Particularly, in a small mobile crane that can add the power of the motor generator 41b as an assist output to the power of the engine 41a during traveling, it is effective when the power of the motor generator 41b is added as an assist output to the power of the engine 41a during crane work. Is.

  That is, when starting the engine 41a from a state in which the engine 41a is stopped by the idling stop function during traveling, the engine 41a is started prior to the start of traveling of the vehicle 10 by the motor generator 41b, thereby accelerating the vehicle 10. The large shaft output required for the can be output.

  Further, when the hydraulic pump 31 is driven from the state where the engine 41a is stopped by the idling stop function during crane work, the hydraulic pump 31 is driven by the power of the motor generator 41b in preference to the engine 41a. As a result, it is possible to reduce a time delay from the start of driving of the hydraulic pump 31 until the pressure of the hydraulic oil circuit 33 reaches a workable pressure. Further, the engine 41a is stopped by the idling stop function at the time of crane work, for example, when the work is on standby when the load is small, such as a state in which no suspended load is hung on the hook block 23a. For this reason, when the idling stop function is canceled and the crane operation is resumed, the crane operation starts smoothly even if the hydraulic pump 31 is driven by the power of the motor generator 41b having a lower output than the engine 41a. It becomes possible. After the crane operation is resumed, the engine 41a is started after the pressure in the hydraulic oil circuit 33 is stabilized. The timing for starting the engine 41a may be an appropriate timing in each work mode.

  Further, when the engine 41a is started from the stopped state of the engine 41a by the idling stop function in the work mode, the hydraulic pump 31 is driven by the motor generator 41b in a state where the connection between the engine 41a and the motor generator 41b is released by the clutch 41e. Driven. As a result, when the engine 41a is started, the hydraulic pump 31 can be driven by the motor generator 41b in a state in which the connection with the engine 41a is released. Therefore, the load for driving the motor generator 41b is reduced, so that the hydraulic oil circuit is further reduced. It is possible to quickly increase the hydraulic pressure in 33.

  Further, when the engine 41a is started from the stopped state of the engine 41a by the idling stop function in the work mode, the engine 41e is started by connecting the motor generator 41b and the engine 41a that are being driven by the clutch 41e. Yes. As a result, the engine 41a can be driven by the motor generator 41b that is being driven, so that the engine 41a can be started more quickly.

  In the above embodiment, the mobile crane 1 including the crane device 20 driven by the hydraulic oil discharged from the hydraulic pump 31 is shown as a work vehicle, but the present invention is not limited to this. The present invention can be applied to a hydraulic work vehicle such as an aerial work vehicle or an excavator as long as it is driven by hydraulic oil discharged from a hydraulic pump.

  In the above embodiment, the PTO mechanism 46 is provided in the torque converter 42. However, if the power of the engine 41a and the motor generator 41b can be taken out, for example, the PTO mechanism is provided in the transmission 43 or other gear box. It may be provided. Further, the drive mechanism may be a transmission system that does not have the torque converter 42.

  In the above embodiment, the control during traveling and the control during crane work are performed by the controller of the overload prevention device 50. However, the present invention is not limited to this. For example, a dedicated travel controller that performs control during travel and a dedicated work controller that performs control during work may be provided separately from the overload prevention device 50.

  In the above-described embodiment, the connection between the engine 41a and the motor generator 41b by the clutch 41e is released (OFF) after it is determined in step S44 in the work idling stop control process that the engine start condition is satisfied. However, the present invention is not limited to this. For example, the connection (OFF) between the engine 41a and the motor generator 41b by the clutch 41e may be performed after determining that the engine stop condition in step S42 is satisfied. In this case, there is an advantage that the operation of the crane device 20 after the engine start condition is satisfied can be started quickly.

  DESCRIPTION OF SYMBOLS 1 ... Mobile crane, 10 ... Vehicle, 20 ... Crane apparatus, 30 ... Hydraulic supply apparatus, 31 ... Hydraulic pump, 40 ... Power unit, 41 ... Power source unit, 41a ... Engine, 41b ... Motor generator, 41c ... Battery, 41d ... motor generator drive control unit, 41e ... clutch, 42 ... torque converter, 43 ... transmission, 44 ... propeller shaft, 50 ... overload prevention device.

Claims (3)

A working vehicle provided with a working device for performing a predetermined work on a traveling body for movement,
An engine capable of outputting the power used to drive the traveling body and drive the working device;
An electric motor that is connectable to the output shaft of the engine and is capable of outputting power used to drive the traveling body and drive the working device;
A hydraulic pump that generates hydraulic pressure that drives the working device by the power of one or both of the engine and the electric motor;
An engine stop means for stopping the engine when a predetermined condition is satisfied in each of a working mode for performing work by the working device and a traveling mode for traveling;
When starting the engine from the engine stop state at the engine stop means in the work mode, the engine power is transmitted to the hydraulic pump after starting the drive of the hydraulic pump by the power of the electric motor, and the engine in the travel mode An engine stop canceling means for starting the engine by the power of an electric motor connected to the engine when the engine is started from the engine stopped state by the stopping means. It has a clutch that can switch the connection between the engine and the electric motor or release the connection,
The engine stop releasing means drives the hydraulic pump by the electric motor in a state where the connection between the engine and the electric motor is released by the clutch when starting the engine from the engine stopped state by the engine stopping means in the work mode. The work vehicle according to claim 1. The engine stop release means starts the engine by connecting the driving motor and the engine with a clutch when starting the engine from the engine stopped state in the engine stop means in the work mode. The work vehicle according to claim 2.

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