JP2016084235A - Pressure oil supply amount control device for vehicle mounted type crane, and vehicle mounted type crane including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pressure oil supply amount control device for a vehicle mounted type crane, capable of providing a more energy-saving effect.SOLUTION: The pressure oil supply amount control device is used for a vehicle mounted type crane including a main hydraulic pump 7 and a sub-hydraulic pump 8 simultaneously driven by the engine 6 of a vehicle. A controller 2 determines the size of a load based on the load information of a suspended load obtained from a load detector 19, increases, when the load is determined to be large, the rotational speed of the engine 6 from the stage of a crane operation amount smaller than that when the load is determined to be small, then merges pressure oil adjusted by a flow control valve 5 with pressure oil discharged from the main hydraulic pump 7, merges, when the load is determined to be small, the pressure oil adjusted by the flow control valve 5 with the pressure oil discharged from the main hydraulic pump 7 from the stage of a crane operation amount smaller than that when the load is determined to be large, and then increases the rotational speed of the engine 6.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a pressure oil supply amount control device for a vehicle-mounted crane and a vehicle-mounted crane including the same.

As a technique for controlling the pressure oil supply amount of a crane, for example, Patent Document 1 discloses a technique for increasing the operation speed of a crane by increasing the discharge amount of pressure oil using two hydraulic pumps. In the technique described in this document, when the pressure oil from the second hydraulic pump is merged with the pressure oil from the first hydraulic pump, the engine torque is defeated by the load when the maximum load is applied to the crane. In order to prevent this, the engine speed is set in advance.
Patent Document 2 discloses a pressure oil supply control device for a vehicle-mounted crane equipped with a dual pump. In the technique described in this document, the timing control for joining the pressure oil from the sub pump to the pressure oil of the main hydraulic pump and the engine speed control by the accelerator cylinder are individually electronically controlled by the controller.

  In the technique described in this document, the engine rotational speed control amount by the accelerator cylinder and the confluence control amount by the flow control valve are stored in advance in the controller as function values for the crane operation amount. The function value stored in advance is a fixed value that is not changed once set, and the operation timing of the merge of the accelerator cylinder and the sub pump with respect to the crane operation amount is always constant.

Japanese Utility Model Publication No. 5-51883 JP 2007-290806 A

However, the crane often moves the boom without load so that the boom must be moved to the loading position before the suspended load is suspended by the hook. When a crane is moved with no load, the load on the hydraulic pump and the operating pressure of the crane are less than when a load is applied such as when lifting a load. For this reason, it is inefficient to use the control amount of the engine speed corresponding to the crane operation amount similar to the maximum load and the control amount of the supplied pressure oil by the merge until no load is hung.
Accordingly, the present invention has been made paying attention to the above-mentioned problems, and provides a pressure oil supply amount control device for a vehicle-mounted crane that can achieve a further energy saving effect, and a vehicle-mounted crane including the same. The task is to do.

  In order to solve the above problems, a pressure oil supply amount control device according to an aspect of the present invention is used in a vehicle-mounted crane equipped with a main hydraulic pump and a sub hydraulic pump that are simultaneously driven by an engine of a vehicle, A pressure oil supply amount control device for controlling a supply amount of pressure oil supplied to a crane, wherein the supply amount of pressure oil discharged from an accelerator cylinder for adjusting the engine speed and the auxiliary hydraulic pump is adjusted. The flow rate control valve, the accelerator cylinder and the flow rate control valve are individually controlled, and the rotational speed of the engine based on the operation input to the crane and the pressure oil discharged from the main hydraulic pump are added to the sub hydraulic pump. A controller for controlling the amount of pressure oil based on the operation input to a control valve for joining the pressure oil and driving the crane; A load detector for detecting the load of the suspended load, and the controller determines the magnitude of the load based on the load information of the suspended load acquired from the load detector and determines that the load is large. When starting the increase of the engine speed from the stage where the amount of crane operation corresponding to the operation input is less than when determining that the load is small, and after the start of the increase of the engine speed, When the pressure oil discharged from the hydraulic pump is started to join the pressure oil from the sub hydraulic pump and the load is determined to be small, the crane operation amount corresponding to the operation input is greater than when the load is determined to be large The pressure oil discharged from the main hydraulic pump is started to join the pressure oil from the sub-hydraulic pump from the stage where there is little, and after the start of merging of the pressure oil from the sub-hydraulic pump, And wherein the increasing the rotation number.

  Here, in the pressure oil supply amount control device according to one aspect of the present invention, when the controller determines that the load is large, the controller performs control based on a preset first control map, and the load is small. When it is judged, control is performed based on the preset second control map, and slow-up control or slow-down control is executed in the transition state when switching between control maps at the time of mutual control switching. Then, the mapping is gradually changed so that the supply flow rate does not change during the transient response, and the crane operation is maintained by keeping the balance of the opening amount according to the rod stroke of the accelerator cylinder and the spool stroke of the flow rate control valve constant. It is preferable to control the speed so as not to change.

According to the pressure oil supply amount control device according to one aspect of the present invention, the magnitude of the load is determined based on the load information of the suspended load, and the engine speed corresponding to the crane operation amount is determined according to the magnitude of the load. It is possible to set the control amount of the ascending distribution, the merge start timing and the supply amount thereof.
In other words, when the load of the suspended load that the crane is hanging is large, the engine speed starts to increase at a stage where the amount of crane operation is small (early timing) than when the load is judged to be small. After the start of the increase in the number, the pressure oil discharged from the auxiliary hydraulic pump and the pressure oil adjusted by the flow control valve starts to merge with the pressure oil discharged from the main hydraulic pump, so the engine torque loses the load and the engine stalls. The engine speed can be secured in advance so as not to occur.

  On the other hand, when the load of the suspended load suspended by the crane is small, such as when moving the crane with no load, the main hydraulic pump uses the pressure oil adjusted by the flow control valve than when the load is judged to be large. Because the engine speed is increased after the start of merging of the pressure oil adjusted by the flow control valve, the merging of the pressure oil discharged from the engine is started at a stage where the crane operation amount is small (early timing). While suppressing an increase in the rotational speed, the operating speed of the crane can be increased by increasing the amount of oil so as not to cause engine stall. Therefore, according to the pressure oil supply amount control apparatus according to one aspect of the present invention, a further energy saving effect can be obtained.

  In order to solve the above problem, a vehicle-mounted crane according to an aspect of the present invention includes the pressure oil supply amount control device according to an aspect of the present invention. According to the vehicle-mounted crane according to one aspect of the present invention, since the pressure oil supply amount control device according to one aspect of the present invention is provided, the magnitude of the load is determined based on the load information of the suspended load. The control amount of the engine speed corresponding to the crane operation amount and the control amount of the supply pressure oil by the merge can be set according to the magnitude of each. Therefore, a further energy saving effect can be obtained.

  Here, the load information of the suspended load acquired from the load detector is information representing the magnitude of the load applied to the hook when the suspended load is lifted, and the strain amount of the load cell provided in the load detector described later. Can be expressed by converting it into an electrical signal. This electric signal is generally a voltage value, but is not limited thereto, and information representing various load magnitudes can be used as the load information if it can be quantified by the controller.

  As described above, according to the present invention, a further energy saving effect can be obtained.

1 is a side view of a vehicle-mounted crane that is an embodiment of a load-type truck crane equipped with a pressure oil supply amount control device according to an aspect of the present invention. It is a figure explaining the pressure oil supply amount control apparatus of the vehicle-mounted crane which concerns on this invention. It is a flowchart of the pressure oil supply amount control process executed in the pressure oil supply amount control device, in which (a) shows the main process, (b) shows the process related to the determination of the slow-up control, and (c) shows FIG. 8 shows processing related to determination of slow-down control. It is a figure explaining the 1st control function (the 1st control map used when it judges that a load is large in pressure oil supply amount control processing). It is a figure explaining the 2nd control function (2nd control map used when it is judged that a load is small in a pressure oil supply amount control process). It is a figure explaining an example of the slow-up control at the time of map transfer, The figure (a) shows the relationship of the control amount of the accelerator cylinder of the map which transfers, The figure (b) shows the spool of the flow control valve The relationship between the control amount with respect to the stroke and the elapsed time during the slow-up control is shown. It is a figure explaining the slow-up control at the time of map shift from small load to large, the same figure (a) shows the relation of the control amount of the accelerator cylinder of the map which moves, the figure (b) is the transition The relationship of the control amount with respect to the spool stroke of the flow control valve between the maps is shown. It is a figure explaining slow down control at the time of map shift from large load to small, (a) in the same figure shows the relationship of the control amount of the accelerator cylinder between the maps to be transferred, (b) in FIG. The relationship of the control amount with respect to the spool stroke of the flow control valve between the maps is shown.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIG. 1, in this vehicle-mounted crane C, a base 15 is fixed on a chassis frame 14 between a loading platform 12 and a cab 13 of the vehicle 10. A column 16 is turnably provided on the base 15, and a boom 17, which is a multistage telescopic boom, is supported on the upper end portion of the column 16 so as to be raised and lowered. The column 16 is provided with a winch (not shown). A wire rope 18 is led from the winch to the tip of the boom 17 and hooked on the hook 11 via a pulley (not shown) at the tip of the boom 17. By turning, the hook 11 is suspended from the tip of the boom 17. A load cell is equipped as a load detector 19 at the tip of the boom 17. The load detector 19 is mounted so that the load cell strain amount changes when a load is applied to the hook 11 (see, for example, a crane load detection device disclosed in Japanese Patent Application Laid-Open No. 2014-73909).

  As shown in FIG. 2, the vehicle-mounted crane C includes a main hydraulic pump 7 and a sub hydraulic pump 8 that are quantitative hydraulic pumps that are simultaneously driven by the engine 6 of the vehicle 10. That is, the main hydraulic pump 7 and the auxiliary hydraulic pump 8 are operated via a PTO (power take-off) 6 a connected to the engine 6 using the engine 6 as a power source. In the main hydraulic pump 7, the pressure oil discharged from the main hydraulic pump 7 is supplied to the main pipeline 27, and the main pipeline 27 is connected to the control valve 3. A return line 29 of the control valve 3 is connected to the tank 9. When the sub hydraulic pump 8 is overloaded between the oil passage on the discharge side of the sub hydraulic pump 8 and the oil passage on the tank 9 side, the relief that relieves the pressure oil on the discharge side to the oil passage on the tank 9 side. A valve 26 is provided.

The pressure oil supply amount control device of the vehicle-mounted crane C has an operation input device 1 for an operator to input a desired operation, as shown in the figure. The operation input device 1 can output an operation signal according to the operation of the operator to the controller 2 via the signal line 50.
The pressure oil supply amount control device has a flow control valve 5, and the discharge side of the auxiliary hydraulic pump 8 is connected to the main circuit 27 via the flow control valve 5, and the pressure oil discharged from the main hydraulic pump 7 In addition, the pressure oil of the auxiliary hydraulic pump 8 adjusted by the flow control valve 5 is joined and supplied to the control valve 3. The flow control valve 5 is connected to the controller 2 via a signal line 52. Based on the control signal from the controller 2, the flow rate control valve 5 can change the spool stroke according to the control amount, and can adjust the flow rate of the pressure oil discharged from the auxiliary hydraulic pump 8 and joining to a predetermined flow rate. ing. Further, the load detector 19 is connected to the controller 2 via a signal line 54. The controller 2 acquires a signal corresponding to the strain amount of the load cell from the load detector 19 as load information of the suspended load (note that the controller 2 will be described in detail later).

  Here, the control valve 3 is a stack type control valve in which switching valves 40 to 43 for supplying and discharging pressure oil necessary for driving the hydraulic actuators 30 to 33 for driving the crane are stacked. . Each switching valve 40-43 is connected to the controller 2 via the signal line 53, and an oil path switching operation is executed based on a control signal from the controller 2 according to the operation signal. In addition, a mechanical operation lever may be attached to each switching valve 40-43, and each switching valve 40-43 may be directly operated according to the operation.

  The switching valves 40 to 43 are provided with operation detectors for detecting the operation contents of the switching valves 40 to 43, respectively. These operation detectors are connected to the controller 2 via the signal line 53, and signals of the operation contents of the switching valves 40 to 43 detected by the operation detectors are input to the controller 2. It has become so. For example, a micro switch or a differential transformer is used as the operation detector of each switching valve 40 to 43.

  The turning hydraulic motor 31 is connected to a turning switching valve 41 capable of supplying and discharging the pressure oil necessary for driving, and the column 16 of the crane C can be turned left and right by the turning hydraulic motor 31. Yes. The boom expansion / contraction hydraulic cylinder 30 is connected to a boom expansion / contraction switching valve 40 that can supply and discharge the pressure oil necessary for driving the boom. The boom raising / lowering hydraulic cylinder 32 supplies pressure oil necessary for the drive. It is connected to a boom raising / lowering switching valve 42 that can supply and discharge. As a result, the boom 17 of the crane C is expanded and contracted by expansion and contraction of the boom expansion / contraction hydraulic cylinder 30, and is undulated by the boom raising / lowering hydraulic cylinder 32. The winch hydraulic motor 33 is connected to a winch switching valve 43 capable of supplying and discharging pressure oil necessary for driving the winch, and the hook 11 of the crane C is operated by the winch hydraulic motor 33 for a winch operation. The hoisting / lowering operation is performed.

  Further, the pressure oil supply amount control device includes an accelerator cylinder 4, and the governor 20 and the accelerator cylinder 4 of the engine 6 are connected to each other by a link 21. The accelerator cylinder 4 is also connected to the controller 2 via a signal line 51. The accelerator cylinder 4 has a rod stroke of the accelerator cylinder 4 according to a control amount based on a control signal from the controller 2. The engine speed can be controlled to a desired speed by adjusting the fuel injection amount to the engine 6 by the variable governor 20. That is, this pressure oil supply amount control device is configured to be able to individually control the number of revolutions of the engine 6 controlled by the accelerator cylinder 4 and the combined flow rate of the pressure oil of the auxiliary hydraulic pump 8 controlled by the flow rate control valve 5. Has been.

Here, the controller 2 determines the magnitude of the load based on the load information of the suspended load, and according to the magnitude of the load, the engine 6, the PTO 6a, etc. by the merging of the main and sub two hydraulic pumps 7, 8 are determined. Pressure oil supply amount control processing for reducing torque load on the drive unit is executed.
Specifically, the controller 2 performs calculation related to pressure oil supply amount control processing for controlling the pressure oil supply amount based on a predetermined control program (both not shown) and the entire system of the control device. CPU to be controlled, ROM that stores CPU control programs in a predetermined area in advance, RAM that stores data read from the ROM and the like and calculation results necessary in the calculation process of the CPU, and the operation input described above An I / F (interface) that mediates input / output of data to / from external devices including the device 1, the control valve 3, the accelerator cylinder 4, the flow rate control valve 5, and the load detector 19 is provided.

  The I / F of the controller 2 transmits data such as an operation signal or a control signal to each other external device via a signal line (reference numerals 50 to 54 indicated by a broken line in FIG. 2) such as a bus for transferring data. Thus, a control signal corresponding to the operation signal input from the operation input device 1 can be output to the control valve 3, the accelerator cylinder 4, and the flow rate control valve 5, respectively. ing.

Hereinafter, the pressure oil supply amount control process executed by the controller 2 will be described. FIG. 3 is a flowchart of a program for executing the pressure oil supply amount control process executed by the controller 2.
In the pressure oil supply amount control device of this embodiment, the controller 2 controls the rod stroke of the accelerator cylinder 4 and the spool of the flow control valve 5 according to the crane operation amount from the operation input device 1, that is, the ratio of operation signal input. The opening amount corresponding to the stroke is controlled, and the control of the pressure oil supply amount is performed to join the pressure oil from the sub hydraulic pump 8 to the pressure oil of the main hydraulic pump 7, and at the same time, the pressure shown in FIG. Oil supply amount control processing is executed. When the pressure oil supply amount control process is executed, first, the process proceeds to step S1, as shown in FIG.

In step S1, the controller 2 acquires the load information of the suspended load from the load detector 19, and determines the magnitude of the load based on the acquired load information of the suspended load. When determining the magnitude of the load, it is possible to make a determination based on various parameters or a predetermined threshold.
For example, load information that responds to a load that causes engine stall if the engine 6 is not idled up is set as a reference value (threshold value), and when the load information of the suspended load obtained is smaller than the reference value, the load is small. It can be determined that the load is large when the load information of the suspended load obtained is larger than the reference value. The reference value of the load information can be freely adjusted in accordance with the engine torque output that is different for each vehicle manufacturer, and the reference value can be arbitrarily determined. However, in this embodiment, as a means for determining the magnitude of the load, it is more simply determined that the load is large when there is a suspended load (when the signal from the load detector 19 is equal to or greater than the initial value of zero). An example in which the load is small when there is no load (when the signal from the load detector 19 is the initial value of zero) will be described. That is, when there is no suspended load, the load is 0 kg.

  That is, in this embodiment, when there is a suspended load, the load is determined to be “large” and the process proceeds to step S2, and when there is no suspended load, the load is determined to be “small” and the process proceeds to step S3. . In step S2, the pressure oil supply amount control by the first control map is executed, and the process is returned. Moreover, in step S3, the pressure oil supply amount control by the second control map is executed, and the process is returned.

Here, the plurality of control maps (control functions) will be described.
The ROM of the controller 2 stores a plurality of control maps as table data. The controller 2 is set so that one control map can be selected from a plurality of control maps according to the magnitude of the load that the crane lifts the suspended load, and the selected one control map is executed by the controller 2. The predetermined pressure oil supply amount control process is referred to. That is, the control signal from the controller 2 output to the accelerator cylinder 4 and the flow rate control valve 5 with respect to the operation signal of the operation input device 1 by the pressure oil supply amount control processing corresponding to one selected control map. It is set individually. In order to improve the processing speed, a plurality of control maps may be read into the RAM, and one control map may be selected from the RAM control map according to the magnitude of the load.

In the pressure oil supply amount control device of the present embodiment, a first control map (first control function) and a second control map (second control function) are provided in the ROM predetermined area of the controller 2 as the plurality of control maps. The two control functions defined in the above are stored in such a manner that they can be referred to as appropriate in a format that can derive a calculation result required in the calculation process of the pressure oil supply amount control process. As described above, the plurality of control functions are selected according to the magnitude of the load that the crane lifts the suspended load.
Each control function is set such that the total discharge flow rate of the main hydraulic pump 7 and the sub hydraulic pump 8 changes proportionally in a plurality of setting stages with respect to the operation signal corresponding to the operation input to the crane. In the first control function and the second control function, the total discharge flow rate itself is the same, but the control balance of the accelerator cylinder 4 and the flow rate control valve 5 is different.

FIG. 4 is a diagram illustrating a first control function (a first control map used for the pressure oil supply amount control process). In the figure, the horizontal axis represents the crane operation amount (operation signal according to the magnitude of the operation input to the crane), and the vertical axis represents the control amount for the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow control valve 5. A graph A indicated by a solid line indicates a control amount of the accelerator cylinder 4, and a graph B indicated by a broken line indicates a control amount of the flow control valve 5 (the same applies to a second control function (FIG. 5) described later). .
The controller 2 determines the presence or absence of a load based on the load information of the suspended load acquired from the load detector 19, and refers to the first control function when determining that there is a load (the load is large).

  As shown in the figure, in the case of the first control function, the rod stroke of the accelerator cylinder 4 is greater than when there is no suspended load and it is determined that the load is small (see the second control function shown in FIG. 5). The amount is increased at a large change rate from the stage where the crane operation amount is small, and the timing for increasing the engine speed is accelerated, and then the pressure oil adjusted by the flow control valve 5 is merged. The pressure oil from the auxiliary hydraulic pump 8 is joined.

  That is, when the controller 2 determines that there is a load (the load is small), the control amount of the accelerator cylinder 4 is set to an early stage based on the first control function in order to secure the engine torque and the pressure oil flow rate. Start up from. Then, for example, the merging of the pressure oil of the auxiliary hydraulic pump 8 adjusted by the flow control valve 5 from the time when the rod stroke of the accelerator cylinder 4 is increased to a predetermined control amount that does not cause the engine stall (when the engine torque is secured). Start. Thereafter, the combined flow rate on the auxiliary hydraulic pump 8 side is also increased, and after merging, the rod stroke of the accelerator cylinder 4 is gradually increased to increase the engine speed, and the pressure oil flow rate according to the amount of crane operation is increased. A series of controls of increasing is executed.

FIG. 5 is a diagram for explaining a second control function (second control map used for the pressure oil supply amount control process). The controller 2 determines the magnitude of the load based on the load information of the suspended load acquired from the load detector 19, and refers to the second control function when determining that there is no suspended load (the load is small).
As shown in the figure, in the case of the second control function, the flow control valve 5 is operated from the initial stage when the amount of crane operation is smaller than when the load is large (when the load is suspended), The joining of the pressure oil of the auxiliary hydraulic pump 8 adjusted by the control valve 5 is started from an early stage, and thereafter the engine speed is gradually increased. Thereafter, after the crane operation amount becomes larger than the predetermined value, the rod stroke of the accelerator cylinder 4 is set to a larger rate of change and the engine speed is increased to increase the pressure oil flow rate according to the crane operation amount. To go.

  That is, when the controller 2 determines that there is no suspended load (no load is detected), the load applied to the engine is light, and therefore the engine torque is not required, so the rod stroke of the accelerator cylinder 4 is gradually increased. However, the operation timing of the flow rate control valve 5 is made earlier than that, that is, the operation is started from the stage where the amount of crane operation corresponding to the operation input is smaller than when the load is judged to be large. The flow rate of pressure oil is increased mainly by the confluence of pressure oil. Then, after sufficiently increasing the combined flow rate, a series of control is executed in which the pressure oil flow rate is increased by increasing the engine speed by mainly increasing the rod stroke of the accelerator cylinder 4 this time.

As described above, the controller 2 of the present embodiment varies the control amounts of the flow control valve 5 and the accelerator cylinder 4 depending on the presence or absence of load detection acquired from the load detector 19. However, in both control functions, the flow rate of pressure oil flowing into the control valve in accordance with the amount of crane operation is the same amount, and the change in flow rate relative to the amount of crane operation is not changed with or without load detection. .
That is, regardless of the selected control function, the characteristics of the engine speed and the combined flow rate of the pressure oil are adjusted according to the control amount of the accelerator cylinder 4 by a test or the like in advance so that the operation speed of the crane does not change. Each control function is set. Note that the graphs of the respective control functions shown in FIGS. 4 and 5 show images that are deformed so as to make the difference between the controls easier to understand. For example, when there is no load, the merging timing of pressure oil in the second control function starts from an early stage where the crane operation amount is small as shown in the graph, but the acceleration cylinder 4 in the second control function The control amount is preferably set larger than that shown in the figure.

By the way, when the control map is switched, if the mapping (characteristic function) is rapidly switched, the balance of the opening amount according to the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow rate control valve 5 is lost, and the supply flow rate is rapidly increased. May increase or decrease. When the supply flow rate changes abruptly, the crane operating speed changes abruptly.
Therefore, in the present embodiment, in order to avoid a sudden change in the supply flow rate at the time of map switching, as shown in FIGS. 3B and 3C, when the control map is switched to another map (or load load). When there is a change), the target value (command value: see FIG. 6B) between the maps changes abruptly, but the rod stroke of the accelerator cylinder 4 and the flow control valve are controlled by slow-up control or slow-down control. The opening amount corresponding to the spool stroke of 5 is gradually changed by a certain amount for a certain period of time to reach the target value.

  In other words, in the present embodiment, when the process proceeds to the pressure oil supply control in step S2, the first pressure oil supply control shown in FIG. 3B is executed. In step S21, it is determined whether or not the shift is from another map. judge. If it is a transition from another map (Yes), the slow-up control is executed in step S22, and if not (No), the pressure oil supply control process in the map is executed in step S23, that is, At the time of shifting to step S2, the above-described pressure oil supply amount control by the first control map is executed.

  When the process proceeds to the pressure oil supply control in step S3, the second pressure oil supply control shown in FIG. 3C is executed, and in step S31, it is determined whether or not the shift is from another map. If it is a transition from another map (Yes), the slow-down control is executed in step S32, otherwise (No) in step S33, the pressure oil supply control process in the map, that is, At the time of shifting to step S3, the pressure oil supply amount control by the second control map is executed.

Next, the operation and effect of the pressure oil supply amount control device of this embodiment will be described.
As described above, this vehicle-mounted crane C is equipped with two main and sub hydraulic pumps 7 and 8, and when the engine speed is idling (when the torque is small), The crane is driven only by the pressure oil, and the pressure oil of the auxiliary hydraulic pump 8 is joined to the hydraulic circuit as the engine speed increases (torque increases). Thereby, according to this vehicle-mounted crane C, sufficient pressure oil can be supplied to perform crane work without increasing the engine speed more than necessary, and an energy saving effect can be obtained.

  In particular, in the pressure oil supply amount control device of the present embodiment, a load signal corresponding to the mass of the suspended load detected by the load detector 19 is sent to the controller 2, and the controller 2 determines the magnitude of the load caused by the suspended load. Further, since the merging of the pressure oil of the auxiliary hydraulic pump 8 and each control amount of the accelerator cylinder 4 are controlled based on different control functions when the load is low and when the load is high, a further energy saving effect can be obtained.

  That is, based on the load information of the suspended load acquired from the load detector 19, the controller 2 combines the engine speed and the pressure oil from the sub pump according to the magnitude of the load lifting the suspended load. When the load is small and the load is small, the pressure oil merging timing is increased and the engine speed is increased later than when the load is large. When the load is large, the load is small. Compared with this, the engine speed is increased early, and then the merging of pressure oil is started, thereby enabling further energy saving and noise reduction.

  On the other hand, in the techniques described in Patent Documents 1 and 2, the control of the engine rotation speed and the timing of the joining of the pressure oil from the sub pump is not distinguished according to the presence or absence of load detection, and the suspended load is not suspended. Sometimes the same control is performed as when there is a load. Therefore, even in the unloaded state where the crane is not lifting the suspended load, the sub hydraulic pump first secures the engine speed sufficiently so that the engine torque does not lose the load increase, as in the case of loading. The engine speed is further increased so that the torque does not lose due to an increase in load caused by the merge.

  On the other hand, in the pressure oil supply amount control device of the present embodiment, the magnitude of the load is determined based on the load information of the suspended load, and the engine speed corresponding to the crane operation amount is controlled according to the magnitude of the load. Since the amount of control and the control amount of merging are set, the first control map corresponding to when the load is detected is the auxiliary hydraulic pressure after increasing the control amount of the accelerator cylinder 4 in order to secure the engine speed. The mapping for starting the merging of the pressure oil of the pump 8 is performed, but the second control map corresponding to the time when no load is detected is from the stage before increasing the control amount of the accelerator cylinder 4 because the operating pressure is low and the pump load is also small. The merging of the auxiliary hydraulic pump 8 can be started. That is, in the pressure oil supply amount control device of the present embodiment, when there is no load, a crane operating speed equivalent to that at the time of load detection can be obtained without increasing the engine speed.

  In addition, according to the pressure oil supply amount control device of the present embodiment, the control amount of the accelerator cylinder 4 is gradually increased in order to prevent the engine stall as the crane operation amount increases in the second control map when there is no load. To increase the engine speed. In other words, as the amount of crane operation increases, the required engine torque is secured at as low an engine speed as possible, while the sub hydraulic pump 8 is merged as fast as possible to increase the flow rate of pressure oil. Yes. Therefore, it is not necessary to increase the engine speed as much as possible while securing the required pressure oil flow rate, which is suitable for energy saving and noise reduction.

  For example, as an actual use at the site of cargo handling work, an operation of loading a plurality of loads on the ground (point X) in FIG. 1 onto a truck bed (point Y) is assumed. In this loading operation, there is no load when the crane hook 11 is moved to the X point where the load is present. Therefore, in this case, the second control map corresponding to no load is used. Next, after the load is hung on the hook 11 at the point X, the first control map corresponding to the presence of the load may be used up to the point Y. In particular, since the above-described vehicle-mounted crane C is mainly used for loading on the loading platform 12, half of the cargo handling work process is often unloaded. Therefore, according to the pressure oil supply amount control device of the present embodiment, it can be said that the effects of energy saving and noise reduction are greater than those of a normal crane.

  Here, in the transition between the control of the first control map (large load) and the second control map (small load), in the present embodiment, in the transient state when the maps are switched, FIG. As shown in FIG. 3 (c), slow-up control or slow-down control is executed, and the mapping is gradually changed so that the supply flow rate during the transient response does not change. Control is made so that the crane operating speed does not change by keeping the balance of the opening amount according to the spool stroke of the valve 5 constant.

  That is, when the second control map (small load) is switched to the first control map (large load), the flow control by the spool of the flow control valve 5 reacts linearly, but the rod stroke of the accelerator cylinder 4 The engine speed with respect to is unable to respond instantaneously, resulting in a time lag. Therefore, even if the signal from the controller 2 is output to the accelerator cylinder 4 and the flow control valve 5 at the same time, and the rod stroke of the accelerator cylinder 4 and the spool of the flow control valve 5 are operated simultaneously and suddenly, the engine speed will be a time lag. Accordingly, the rotation of the hydraulic pump also rises with a delay, so it takes some time until the supply flow rate increases. Therefore, when the target value of the map changes suddenly, if the opening amount corresponding to the spool stroke of the flow control valve 5 and the rod stroke of the accelerator cylinder 4 are changed suddenly, the rod stroke of the accelerator cylinder 4 itself is Although the response to the change in the opening amount according to the spool stroke of the flow control valve 5 is made, the supply flow rate does not catch up with the required flow rate according to the change in the opening amount according to the spool stroke of the flow control valve 5. The balance between the required flow rate and the supply flow rate is lost.

  For example, as shown in FIG. 6, when the crane operation amount is 50% and the crane operation is performed, when the load is small, the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow control valve 5 in the second control map. The target value (command value) is 2 mm. It is assumed that when the load increases from this state, the target value (command value) of the rod stroke and the spool stroke is changed to 7 mm in the first control map. At this time, the slow-up control is executed, and the target value for the elapsed time considering the responsiveness of the supply flow rate to the rod stroke of the accelerator cylinder 4 is set to a function separately provided as shown in the graph of FIG. Based on this slow-up control function, the spool stroke is changed by a certain amount at a certain time to reach the target value.

  Regarding the response delay at the time of map switching, if the supply flow rate obtained from the spool stroke control amount of the flow rate control valve according to the rod stroke control amount of the accelerator cylinder 4 can be fed back, a map of large load and small load Only if the engine cylinder speed control amount by the accelerator cylinder 4 and the control amount of the supply pressure oil by the merge are monitored to be kept constant, the rod stroke of the accelerator cylinder 4 and the supply flow rate are fed back. The control command may be dealt with by approaching the theoretical value.

  In the present embodiment, when the second control map (small load) is switched to the first control map (large load), as shown in FIG. 7, in order to enable the supply flow rate to respond to the required flow rate, By the slow-up control, the opening amount corresponding to the spool stroke of the flow control valve 5 and the rod stroke of the accelerator cylinder 4 are gradually changed so that the supply flow rate is constant even when the map is switched from a small load state to a large load state. It compensates to become.

  Thereby, for example, even if the map is switched when the tension of the wire rope becomes equal to the mass of the suspended load at the moment when the suspended load is separated from the ground, problems such as load lashing do not occur. In FIG. 7, graphs A1 and B1 indicated by solid lines indicate the control amount of the accelerator cylinder 4 and the control amount of the flow rate control valve 5 in the first control map, respectively, and graphs A2 and B2 indicated by two-dot chain lines indicate The control amount of the accelerator cylinder 4 and the control amount of the flow control valve 5 in the second control map are respectively shown.

  On the other hand, when switching from the first control map (large load) to the second control map (small load), the response of the supply flow rate to the rod stroke of the accelerator cylinder 4 is considered as shown in FIG. In addition, the opening amount corresponding to the spool stroke of the flow rate control valve 5 and the rod stroke of the accelerator cylinder 4 are gradually changed by the slow-down control, whereby the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow rate control valve 5 are changed. The balance of the corresponding opening amount is kept constant, and the supply flow rate is compensated constant so that the crane operating speed does not change.

In FIG. 8, graphs A1 and B1 indicated by two-dot chain lines indicate the control amount of the accelerator cylinder 4 and the control amount of the flow control valve 5 in the first control map, respectively, and graphs A2 and B2 indicated by solid lines are The control amount of the accelerator cylinder 4 and the control amount of the flow control valve 5 in the second control map are respectively shown.
As a specific operation, for example, in the above-described loading operation, the operator performs the hoisting of the hook from the state where the suspended load is hung on the hook while the suspended load is placed on the ground. At this time, since the load is small, the second control map (small load) is applied, and the opening amount corresponding to the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow control valve 5 is controlled based on the second control map. Is done.

Next, when the operator continues the hook hoisting operation and the suspended load leaves the ground, the load becomes large. As a result, the first control map (large load) is applied, but since the second control map (small load) is switched to the first control map (large load), slow-up control is performed, and the accelerator cylinder The opening amount corresponding to the rod stroke 4 and the spool stroke of the flow rate control valve 5 is gradually switched from a map with a small load to a map with a large load.
Next, the operator moves the suspended load to a target position by raising / lowering the boom, extending / contracting the boom, turning, and winding the hook. During this time, the first control map (large load) is applied. The operator performs the hook lowering operation after moving the suspended load to above the target location. The first control map (large load) is applied until the suspended load comes into contact with the ground by the hook lowering operation.

  Next, the operator continues the hook lowering operation, and when the suspended load comes into contact with the ground, the load becomes small. Therefore, the second control map (small load) is applied, but the first control map (large load) is applied. Since switching to the second control map (small load), slow down control is performed, and the load gradually decreases from the map of the large load depending on the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow control valve 5 respectively. Switch to the map. In map switching to the no-load side at the time of unloading, it is possible to change the map without performing slowdown control, but it is desirable that the operation speed does not change even when there is no load. In this embodiment, the map is gradually switched by the slow-down control.

Note that the pressure oil supply amount control device for a vehicle-mounted crane according to the present invention and the vehicle-mounted crane including the same are not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. Of course, it is possible.
For example, in the above-described embodiment, in the pressure oil supply amount control process executed by the controller 2, a plurality of different control functions that can be selected have been described as two types. However, the present invention is not limited to this. It is good also as a structure which can be selected.

  Further, for example, in the above-described embodiment, the controller 2 has been described as an example of determining the magnitude of the load in the pressure oil supply amount control process executed by itself. However, the present invention is not limited to this. For example, the load detector 19 is turned on / off. When the wire rope tension is detectable, the controller 2 determines the magnitude of the load according to whether the load is present or not, and switches between multiple control functions. Alternatively, the timing at the start of operation of the accelerator cylinder 4 and the start of operation of the flow control valve may be controlled by the control function.

  Further, for example, the control method at the time of switching between the first control map (large load) and the second control map (small load) is not limited to the example of the slow-up control or the slow-down control of the above embodiment. For example, as another control example, when the crane operation by the operator is continued, the opening amount corresponding to the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow rate control valve 5 is based only on the change in the magnitude of the load. If there is a change from a low load state to a high load state (or if there is a load change) without switching the mapping, the second control map with a low load will be displayed until the crane operation is temporarily stopped. You may control to apply. Then, the first control map (large load) may be applied when the operator stops the operation once and the crane operation is input again (for example, after pressing the load by ground cutting or the like, during the re-operation). Good.

Further, even when the load is switched from the large load state to the small load state, the large load first control map is applied until the crane operation by the operator is stopped. After that, when the operation is once stopped and then operated again, the second control map with a small load is applied.
The reason is that, similar to the control in the above embodiment, when the mapping (characteristic function) of the opening amount corresponding to the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow rate control valve 5 is suddenly switched, the rod stroke of the accelerator cylinder 4 is changed. The balance of the opening amount according to the spool stroke of the flow rate control valve 5 may be lost and the supply flow rate may increase or decrease rapidly. If the supply flow rate changes abruptly, the crane operating speed will change abruptly. Because it becomes. In this case, there is no need to provide slow-down control at the time of map transition, and the cost is reduced accordingly.

[Operation example for other controls]
First, the operator winds the hook from the state where the suspended load is hung on the hook while the suspended load is placed on the ground. At this time, since the load is small, the second control map (small load) is applied, and the opening amount corresponding to the rod stroke of the accelerator cylinder 4 and the spool stroke of the flow control valve 5 is controlled based on the second control map. Is done.
Next, when the operator continues the hook hoisting operation and the suspended load leaves the ground, the load becomes large. However, when the hook hoisting operation is continued, the suspended load is separated from the ground (the load is large), but since the crane operation of the operator is not stopped at this point, the mapping is not switched.

  Next, when the operator temporarily stops the hook hoisting operation and performs the hoisting operation again, the operator switches from the second control map (small load) to the first control map (large load), and the first control map (large load). The hook hoisting operation is resumed based on the above. The operator moves the suspended load to a target position by raising and lowering the boom, extending and retracting the boom, and turning. During this time, the first control map (large load) is applied based on the load information of the suspended load acquired from the load detector. The operator performs the hook lowering operation after moving the suspended load to above the target location. The first control map (large load) is applied until the suspended load comes into contact with the ground by the hook lowering operation.

Next, the operator continues the hook lowering operation, and when the suspended load comes into contact with the ground, the load becomes small. However, at this time, the crane operation is not stopped by the operator, so the mapping is not switched to the small load mapping. After that, when the operator temporarily stops the hook lowering operation and performs the lowering operation again, the first control map (large load) is switched to the second control map (small load), and the second control map (load) Small), the hook lowering operation is resumed.
Thus, even when the above-described other control is adopted, the magnitude of the load is determined based on the load information of the suspended load, and the engine speed corresponding to the crane operation amount is determined according to the magnitude of the load. A control amount and a control amount for merging can be set. Therefore, a further energy saving effect can be obtained.

DESCRIPTION OF SYMBOLS 1 Operation input device 2 Controller 3 Control valve 4 Accelerator cylinder 5 Flow control valve 6 Engine 7 Main hydraulic pump 8 Sub hydraulic pump 9 Tank 10 Vehicle 11 Hook 12 Loading platform 13 Operation room 14 Chassis frame 15 Base 16 Column 17 Boom 18 Wire rope 19 Load detector 20 Governor 21 Link 27 Main circuit 26 Relief valve 30, 31, 32, 33 Actuator 40, 41, 42, 43 Switching valve 50, 51, 52, 53, 54 Signal line

Claims (3)

A pressure oil supply amount control device for controlling a supply amount of pressure oil to be used for a vehicle-mounted crane equipped with a main hydraulic pump and a sub hydraulic pump that are simultaneously driven by a vehicle engine,
An accelerator cylinder that adjusts the rotational speed of the engine, a flow rate control valve that adjusts the supply amount of pressure oil discharged from the auxiliary hydraulic pump, and the accelerator cylinder and the flow rate control valve are individually controlled, and The engine speed based on the operation input to the crane and the operation input to the control valve for driving the crane by joining the pressure oil discharged from the main hydraulic pump with the pressure oil of the sub hydraulic pump A controller for controlling the amount of pressure oil based thereon, and a load detector for detecting the load of the suspended load suspended by the crane,
The controller determines the magnitude of the load based on the load information of the suspended load acquired from the load detector,
When it is determined that the load is large, the increase in the engine speed is started from the stage where the amount of crane operation corresponding to the operation input is less than when the load is determined to be small, and the increase in the engine speed is started. Later, the pressure oil discharged from the main hydraulic pump is started to join the pressure oil from the sub hydraulic pump,
When it is determined that the load is small, the pressure oil discharged from the main hydraulic pump is changed to the pressure oil discharged from the main hydraulic pump from the stage where the amount of crane operation corresponding to the operation input is smaller than when the load is determined to be large. , And the number of revolutions of the engine is increased after the start of merging of the pressure oil from the auxiliary hydraulic pump.   The controller performs control based on a preset first control map when it is determined that the load is large, and performs control based on a preset second control map when it is determined that the load is small. In addition, in the transition state when switching between the control maps, slow-up control or slow-down control is executed in the transition state when switching the control map, and the mapping is gradually changed so that the supply flow rate during the transient response does not change The crane operating speed is controlled so as not to change by keeping the balance of the opening amount according to the rod stroke of the accelerator cylinder and the spool stroke of the flow control valve constant. Pressure oil supply amount control device.   A vehicle-mounted crane comprising the pressure oil supply amount control device according to claim 1.

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