JP6433932B2 - Dump truck body lifting assist control system - Google Patents

Description

  The present invention relates to a body lifting assist control system that assists expansion and contraction of a hoist cylinder when performing loading and unloading operations particularly in a dump truck traveling in a mine, a quarry site, or the like.

  At mines and quarry sites, loading and unloading are performed frequently.To shorten the loading and unloading time, the operator depresses the accelerator pedal to maximize the engine speed, increase the discharge rate of the hydraulic pump, The expansion / contraction time may be shortened.

  In recent years, interest in environmental impacts has increased, and demand for energy saving has been increasing in order to reduce fuel costs.

  On the other hand, there is known a body lifting speed control device for a dump truck that can mitigate an impact by controlling the lifting speed at the time of sitting and standing when the body of the dump truck is lifted (see, for example, Patent Document 1).

JP 2004-268646 A

  The body elevating speed control device of Patent Document 1 controls the elevating speed of a body (vessel) on which a load is loaded.

  However, in the conventional dump truck using the body lifting speed control device of Patent Document 1, in order to shorten the expansion / contraction time of the hoist cylinder, it is necessary for the operator to depress the accelerator pedal to the maximum, which is a burden on the operator. It was.

  The objective of this invention is providing the body raising / lowering assist control system which can reduce the burden of the operator at the time of hoist operation.

(1) In order to achieve the above object, the present invention provides a body for loading a load, a hoist cylinder for raising and lowering the body, a hoist lever for operating the hoist cylinder, and supplying pressure oil to the hoist cylinder. A hydraulic pump, an engine that drives the hydraulic pump, a load dump brake, an accelerator pedal, a controller that controls the rotation of the engine according to the amount of operation of the accelerator pedal, and a target engine speed that is maximized Power mode to set the number, eco mode to set the target engine speed of the engine to the minimum engine speed, and normal mode to set the engine target engine speed to the engine speed according to the amount of operation of the accelerator pedal. the control mode includes a selector switch, the controller switching, provided that the vehicle is stopped 1 , A condition 2 that the load dump brake is applied, the condition 3 that the hoist lever is operated, the body determines whether to satisfy the condition 4 that it is unloaded, respectively (A) When the power mode is selected and the condition 1, the condition 2 and the condition 3 are satisfied and the condition 4 is not satisfied, the engine speed is set to the maximum engine speed. (B) when the eco-mode is selected and the conditions 1, 2 and 3 are satisfied, the engine is controlled so that the engine speed becomes the minimum engine speed; (C) When the power mode is selected and the condition 1, the condition 2 and the condition 3 are not satisfied, and the condition 4 is satisfied, the engine speed is When the engine is controlled so that the number of revolutions corresponds to the amount of operation of the accelerator pedal, (d) when the eco mode is selected and any one of the conditions 1, 2 and 3 is not satisfied The engine is controlled so that the engine speed becomes a speed corresponding to an operation amount of the accelerator pedal; and (e) when the normal mode is selected, the engine speed is the accelerator pedal. The engine is controlled so that the number of revolutions corresponds to the operation amount .

As a result, even if the accelerator pedal is not depressed, the engine output becomes the maximum number of revolutions in the power mode . For this reason, the burden of the operator at the time of hoist operation can be reduced. Moreover, the expansion / contraction time of the hoist cylinder is shortened.

  According to the present invention, it is possible to reduce the burden on the operator during the hoist operation. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

1 is an overall configuration diagram of a dump truck using a body lifting assist control system according to an embodiment of the present invention. It is a block diagram of the body raising / lowering assist control system which is embodiment of this invention. The graph which shows the relationship between the engine speed in the control mode (power mode, normal mode, eco-mode) selected with the control mode changeover switch used for the body raising / lowering assist control system which is embodiment of this invention, and the operation amount of an accelerator pedal. It is. It is a figure for demonstrating the function of the controller used for the body raising / lowering assist control system which is embodiment of this invention. It is a flowchart which shows the control content of the controller used for the body raising / lowering assist control system which is embodiment of this invention.

  Hereinafter, the configuration and operation of the body lifting assist control system according to the embodiment of the present invention will be described with reference to FIGS. The body lifting assist control system is a system that controls lifting of a body (vessel) in a dump truck.

  Initially, the whole structure of a dump truck is demonstrated using FIG. FIG. 1 is an overall configuration diagram of a dump truck using a body lifting assist control system according to an embodiment of the present invention.

  The dump truck includes a body 1, a hoist cylinder 2, and a controller 3. The controller 3 controls the pressure oil supplied to the hoist cylinder 2. A body 1 is connected to the hoist cylinder 2. As the hoist cylinder 2 expands and contracts, the body 1 moves up and down.

  Next, the configuration of the body lifting assist control system used for the dump truck will be described in detail with reference to FIG. FIG. 2 is a configuration diagram of the body lifting assist control system 100 according to the embodiment of the present invention.

  The body lifting assist control system 100 includes a body 1, a hoist cylinder 2, a controller 3, a control mode switch 4, a hoist lever 5, a load dump brake switch 6, an accelerator pedal 7, an electromagnetic switching valve 8, an electromagnetic pickup sensor 9, and a tire 10. , A hydraulic sensor 12, an engine Eng, a generator ALT, and a hydraulic pump P.

  A generator ALT and a hydraulic pump P are connected to the engine Eng. The engine Eng drives the generator ALT to generate electric power. In addition, the hydraulic pump P is driven by the engine Eng, and the pressure oil is supplied to the hoist cylinder 2 via the electromagnetic switching valve 8.

  The accelerator pedal 7 supplies a signal indicating the operation amount p of the accelerator pedal 9 to the controller 3 in accordance with a user operation. The controller 3 controls the rotation of the engine Eng based on the operation amount p of the accelerator pedal 9.

  The hoist lever 5 is a lever for operating (expanding / contracting) the hoist cylinder 2. The hoist lever 5 supplies an operation amount q (including the operation direction of the hoist lever 5) of the hoist lever 5 to the controller 3 in accordance with a user operation. The controller 3 controls the electromagnetic switching valve 8 based on the operation amount q of the hoist lever 5. Thereby, the pressure oil supplied to the hoist cylinder 2 from the hydraulic pump P is controlled, and the hoist cylinder 2 expands and contracts.

  The load dump brake switch 6 is a switch for operating the load dump brake. The load dump brake is a brake used when loading and unloading loads. When the load dump brake switch 6 is turned on, the hydraulic brake for the rear wheel is activated. The load dump brake switch 6 supplies a signal indicating the on / off state r of the load dump brake switch 6 to the controller 3 in accordance with a user operation.

  The control mode switching switch 4 is a switch for switching a method (control mode) for controlling the engine Eng. The control mode selector switch 4 supplies the controller 3 with the control mode m selected by the user. The control mode includes a power mode, a normal mode, and an economy mode (eco mode). Details of the control mode will be described later with reference to FIG.

  The electromagnetic switching valve 8 includes a switching valve, a first solenoid, a second solenoid, and the like. When the first solenoid and the second solenoid are energized, the switching valve moves.

  The electromagnetic pickup sensor 9 supplies a signal indicating the rotational speed ω of the tire (wheel) 10 to the controller 3. The controller 3 determines whether or not the vehicle is stopped based on the rotational speed ω of the wheel 10.

  The oil pressure sensor 12 detects the oil pressure s of the hoist cylinder 2 and supplies the oil pressure s to the controller 3. Based on the extension of the hoist cylinder 2, the controller 3 determines whether or not the body 1 on which the load is loaded is empty. Specifically, the controller 3 determines that the body 1 is empty when the hoist cylinder 2 is fully extended, and determines that it is not empty when the hoist cylinder 2 is not fully extended. The controller 3 may determine whether or not the body 1 is empty based on a detection value of a pressure sensor of a suspension cylinder (not shown).

  Next, the control mode m selected by the control mode changeover switch 4 will be described with reference to FIG. FIG. 3 shows the engine speed (target speed Nr) in the control mode (power mode, normal mode, eco mode) selected by the control mode changeover switch 4 used in the body lifting assist control system 100 according to the embodiment of the present invention. ) And the operation amount p of the accelerator pedal 7 is a graph showing the relationship. In FIG. 3, the vertical axis represents the engine speed (target speed Nr), and the horizontal axis represents the operation amount p of the accelerator pedal 7. The operation amount p (%) indicates a ratio with respect to the maximum operation amount of the accelerator pedal 7.

  When the control mode m is the power mode, the target rotational speed Nr is constant (maximum rotational speed Nmax) regardless of the operation amount p of the accelerator pedal 7. In this case, the controller 3 sets the target engine speed Nr of the engine Eng to the maximum engine speed Nmax. Thereby, the discharge amount of the hydraulic pump P is maximized. In the present embodiment, the maximum rotation speed Nmax = 1900 rpm, but it may be changed for each user.

  When the control mode m is the normal mode, the target rotational speed Nr increases as the operation amount p of the accelerator pedal 7 increases. The controller 3 controls the engine Eng so that the engine speed Ne fed back from the engine Eng becomes the target speed Nr corresponding to the operation amount p of the accelerator pedal 7. In FIG. 3, the target rotation speed Nr is the minimum rotation speed Nmin when p = 0, and the maximum rotation speed Nmax when p = 100. In the present embodiment, the minimum rotation speed Nmin = 650 rpm, but may be changed for each user.

  When the control mode m is the eco mode, the target rotational speed Nr is constant (minimum rotational speed Nmin) regardless of the operation amount p of the accelerator pedal 7. In this case, the controller 3 sets the target engine speed Nr of the engine Eng to the minimum engine speed Nmin. Thereby, the discharge amount of the hydraulic pump P is minimized.

  Next, the function of the controller 3 will be described with reference to FIG. FIG. 4 is a diagram for explaining functions of the controller 3 used in the body lifting assist control system 100 according to the embodiment of the present invention.

  The controller 3 includes a vehicle state determination unit 301, an engine rotation control unit 302, and an electromagnetic switching valve control unit 303.

  The vehicle state determination unit 301 determines whether the control mode is the power mode, the normal mode, or the eco mode based on the control mode m supplied from the control mode changeover switch 4.

  The vehicle state determination unit 301 calculates the vehicle speed from the wheel rotation speed ω supplied from the electromagnetic pickup sensor 9. The vehicle state determination unit 301 determines whether the vehicle is stopped based on the calculated vehicle speed. Specifically, when the vehicle speed is 0 km / h, the vehicle state determination unit 301 determines that the vehicle is stopped.

  The vehicle state determination unit 301 determines whether or not the load dump brake is operating based on the on / off state r of the load dump brake supplied from the load dump brake switch 6.

  The vehicle state determination unit 301 determines whether or not the hoist lever 5 is operated based on the operation amount q of the hoist lever 5 supplied from the hoist lever 5.

  The vehicle state determination unit 301 determines whether the body 1 is empty based on the extension of the hoist cylinder 2.

  The engine rotation control unit 302 sets the target engine speed Nr of the engine Eng based on the determination result of the vehicle state determination unit 301 and the operation amount p of the accelerator pedal 7. The engine speed control unit 302 controls the engine Eng so that the engine speed Ne fed back from the engine Eng becomes the target speed Nr. At this time, the engine rotation control unit 302 supplies an engine control signal to an engine control device (such as a governor) (not shown). The engine control device controls the fuel injected into the combustion chamber of the engine Eng based on the engine control signal.

  Based on the operation amount q of the hoist lever 5, the electromagnetic switching valve control unit 303 switches the switching valve control signal R for energizing the first solenoid of the electromagnetic switching valve 8 and the energization to the second solenoid. An on / off switching valve control signal L is supplied to the electromagnetic switching valve 8. The electromagnetic switching valve 8 switches the oil path based on the switching valve control signals R and L. Thereby, the pressure oil supplied from the hydraulic pump P is controlled, and the hoist cylinder 2 expands and contracts.

  Next, the operation of the controller 3 used in the body lifting assist control system 100 will be described with reference to FIG. FIG. 5 is a flowchart showing the control contents of the controller 3 used in the body lifting assist control system 100 according to the embodiment of the present invention.

(1) When power mode is selected
First, the operation of the controller 3 (vehicle state determination unit 301, engine rotation control unit 302) when the power mode is selected by the control mode changeover switch 4 will be described. In the following, it is assumed that the vehicle is stopped, the load dump brake is operating, and the hoist lever 5 is operated. Here, for example, it is assumed that the hoist cylinder 2 is extended and the load is loaded and unloaded. This state is a state when the body 1 shifts from the lying posture to the standing posture.

  The engine rotation control unit 302 sets the output of the engine Eng as the engine rotation output in the normal mode when the engine starts (step S10). Specifically, the engine speed control unit 302 controls the engine Eng so that the engine speed Ne fed back from the engine Eng becomes a target speed Nr corresponding to the operation amount p of the accelerator pedal 7.

  The vehicle state determination part 301 receives selection of the control mode m from the control mode changeover switch 4 (step S15). In this example, the vehicle state determination unit 301 accepts selection of a power mode as the control mode m.

  The vehicle state determination unit 301 determines whether or not the power mode is selected (step S20). In this example, since the power mode is selected, YES is obtained in step S20.

  The vehicle state determination unit 301 determines whether or not the vehicle is stopped (step 30). In this example, since the vehicle is stopped, YES is obtained in step S30.

  The vehicle state determination unit 301 determines whether or not the load dump brake is operating (step S40). In this example, since the load dump brake is operating, YES is obtained in step S40.

  The vehicle state determination unit 301 determines whether or not the hoist lever 5 is operated (step S50). In this example, since the hoist lever 5 is operated, YES is obtained in step S50.

  The vehicle state determination unit 301 determines whether or not the body 1 is empty (step S60). Specifically, the vehicle state determination unit 301 determines whether or not the hoist cylinder 2 is fully extended. The vehicle state determination unit 301 determines that the hoist cylinder 2 is empty when it is fully extended.

  When the vehicle state determination unit 301 determines that the body 1 is not empty (step S60; NO), the output of the engine Eng is set as the engine rotation output in the power mode (step S70). Specifically, the engine speed control unit 302 sets the target engine speed Nr of the engine Eng to the maximum engine speed Nmax. Thereby, the engine speed Ne of the engine Eng becomes the maximum speed Nmax, and the discharge amount of the hydraulic pump P becomes the maximum. For this reason, the expansion / contraction time of the hoist cylinder 2 can be shortened. Thereafter, the process returns to step S15.

(2) When eco-mode is selected
Next, the operation of the controller 3 (vehicle state determination unit 301, engine rotation control unit 302) when the eco mode is selected by the control mode changeover switch 4 will be described. In the following, it is assumed that the vehicle is stopped, the load dump brake is operating, and the hoist lever 5 is operated. Here, for example, it is assumed that the hoist cylinder 2 is contracted and the body 1 is shifted from the standing posture to the lying posture.

  The engine rotation control unit 302 sets the output of the engine Eng as the engine rotation output in the normal mode when the engine starts (step S10).

  Subsequently, in this example, since the eco mode is selected, NO is determined in step S20, and YES is determined in step S80.

  The vehicle state determination unit 301 determines whether or not the vehicle is stopped (step 90). In this example, since the vehicle is stopped, YES is obtained in step S90.

  The vehicle state determination unit 301 determines whether or not the load dump brake is operating (step S100). In this example, since the load dump brake is operating, YES is obtained in step S100.

  The vehicle state determination unit 301 determines whether or not the hoist lever 5 is operated (step S110). In this example, since the hoist lever 5 is operated, YES is obtained in step S110.

  The engine rotation control unit 302 changes the output of the engine Eng to the engine rotation output of the eco mode (step S120). Specifically, the engine rotation control unit 302 sets the target engine speed Nr of the engine Eng to the minimum engine speed Nmin. Thereby, the engine speed Ne of the engine Eng becomes the maximum speed Nmin, and the discharge amount of the hydraulic pump P becomes the minimum. For this reason, although the expansion-contraction time of the hoist cylinder 2 increases, it can save energy. Thereafter, the process returns to step S15.

(3) When normal mode is selected
Next, the operation of the controller 3 (the vehicle state determination unit 301 and the engine rotation control unit 302) when the normal mode is selected with the control mode switch 4 will be described. In the following, it is assumed that the vehicle is stopped, the load dump brake is operating, and the hoist lever 5 is operated.

  The engine rotation control unit 302 sets the output of the engine Eng as the engine rotation output in the normal mode when the engine starts (step S10).

  Subsequently, in this example, since the normal mode is selected, NO is determined in step S20, and NO is determined in step S80. Thereafter, the process returns to step S15.

  As described above, according to the present embodiment, the burden on the operator during the hoist operation can be reduced.

  For example, if the power mode is selected in advance with the control mode changeover switch 4 (switching device) and a predetermined condition is satisfied, the operator assists expansion and contraction of the hoist cylinder when the body is raised and lowered without operating the accelerator pedal 7. be able to. Further, when the operator arbitrarily operates the switching device, the eco mode, the power mode, and no control (normal mode) can be selected, and the optimum operation can be performed at the work site.

  The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. A part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. It is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

1 ... Body (vessel)
2 ... Hoist cylinder 3 ... Controller 4 ... Control mode switch 5 ... Hoist lever 6 ... Load dump brake switch 7 ... Accelerator pedal 8 ... Electromagnetic switch valve 9 ... Electromagnetic pickup sensor 10 ... Tire 12 ... Hydraulic sensor Eng ... Engine ALT ... Power generation Machine P ... Hydraulic pump

Claims (1)

A body for loading a load, a hoist cylinder for raising and lowering the body, a hoist lever for operating the hoist cylinder, a hydraulic pump for supplying pressure oil to the hoist cylinder, an engine for driving the hydraulic pump, and a load dump A brake, an accelerator pedal, a controller for controlling the rotation of the engine according to an operation amount of the accelerator pedal, a power mode for setting the target rotation speed of the engine to a maximum rotation speed, and a minimum target rotation speed of the engine A control mode changeover switch for switching to any one of an eco mode for setting the rotation speed and a normal mode for setting the target rotation speed of the engine to a rotation speed according to the operation amount of the accelerator pedal
The controller is
Condition 1 that the vehicle is stopped,
Condition 2 that the load dump brake is operating, and
Condition 3 that the hoist lever is operated, and
Condition 4 that the body is empty;
A determines whether or not satisfied, respectively,
(A) When the power mode is selected and the condition 1, the condition 2 and the condition 3 are satisfied, and the condition 4 is not satisfied, the engine is controlled so that the engine speed becomes the maximum engine speed. Control
(B) When the eco mode is selected and the condition 1, the condition 2 and the condition 3 are satisfied, the engine is controlled such that the engine speed becomes the minimum speed;
(C) When the power mode is selected and one of the condition 1, the condition 2 and the condition 3 is not satisfied, and when the condition 4 is satisfied, the engine speed is the operation amount of the accelerator pedal. Controlling the engine so that the number of revolutions according to the
(D) When the eco mode is selected and any one of the condition 1, the condition 2 and the condition 3 is not satisfied, the engine speed is set to a speed corresponding to the operation amount of the accelerator pedal. To control the engine,
(E) When the normal mode is selected , the dump truck body lifting assist is characterized in that the engine is controlled so that the rotational speed of the engine becomes a rotational speed corresponding to an operation amount of the accelerator pedal. Control system.

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