JP6474702B2 - Drive device for work machine - Google Patents

Description

  The present invention relates to a drive device for a work machine.

  In recent years, in construction machines such as hydraulic excavators and wheel loaders, attention has been focused on fuel and energy saving systems for reducing the consumption rate. As an energy saving system, application of a hydraulic system in which a hydraulic pump and a hydraulic actuator are directly connected via a flow path without using a throttle valve, and the hydraulic actuator is directly controlled by controlling a discharge flow rate from the hydraulic pump is being studied. According to this hydraulic system, since the hydraulic pump discharges only the flow rate required by the hydraulic actuator, there is no loss due to the diversion.

  When this hydraulic system is applied to a hydraulic excavator, a flow path switching circuit is provided on the flow path connecting the hydraulic pump and the hydraulic actuator to selectively merge the hydraulic oil discharged from a plurality of hydraulic pumps. To drive. At this time, since each hydraulic pump is assigned to one hydraulic actuator according to a certain connection order, depending on the operation of the hydraulic excavator, many hydraulic pumps connected to light load hydraulic actuators or many heavy load hydraulic actuators are connected. It is assumed that there is a difference in the degree of wear of these hydraulic pumps.

  As a result, when a hydraulic pump with a high accumulated degree of failure breaks down, the operation of the hydraulic excavator must be stopped even if the other hydraulic pumps are hardly consumed, and the operating rate of the hydraulic excavator is reduced. The problem arises.

  In response to such a problem, in a hydraulic system in which a plurality of hydraulic pumps can be connected to a plurality of hydraulic actuators, the data related to the operation of each hydraulic pump is measured to calculate the amount of work, and the accumulation of the work. There has been proposed a hydraulic system that averages the remaining life of a hydraulic pump by connecting to the hydraulic actuator in order of the hydraulic pump having the smallest (accumulated work amount) (hereinafter, cumulative work amount) (for example, Patent Document 1). reference).

International Publication No. WO2010 / 048257

  In the hydraulic system described above, as data relating to the operation of the motor and the hydraulic pump, for example, current and voltage applied to the motor, motor temperature, speed, torque, total operation time, etc. are measured, and the average remaining life of the hydraulic pump is measured. Therefore, the work of each hydraulic pump is calculated from the above data, and the connection between the hydraulic pump and the hydraulic actuator is controlled according to the accumulated work.

  For this reason, if there is an error in the measurement means that measures the data of a certain hydraulic pump, the accumulated error is added to the accumulated work amount, making it difficult to accurately estimate and average the accumulated work amount. The problem arises that the remaining life of the pump cannot be averaged.

  The present invention has been made on the basis of the above-mentioned matters, and its purpose is to average the lifespan of each hydraulic pump without measuring data regarding the operation of each hydraulic pump and calculating the accumulated work amount. An object of the present invention is to provide a drive device for a work machine that can be used.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-described problems. To give an example, an operation member operated by an operator, a plurality of hydraulic pumps, and a plurality of discharge flow rates of the plurality of hydraulic pumps are controlled. A regulator, a plurality of hydraulic actuators connected to the plurality of hydraulic pumps by a flow path, and a flow path connecting the plurality of hydraulic pumps and the plurality of hydraulic actuators, respectively, A plurality of switching valves that enable one hydraulic pump to be connected to one hydraulic actuator among the plurality of hydraulic actuators, and respective command signals for controlling the plurality of regulators and the plurality of switching valves. A drive device for a work machine comprising a controller, wherein the controller is responsive to an operation amount of the operation member. A required pump calculation unit that calculates a required flow rate of each of the plurality of hydraulic actuators as a ratio with a rated flow rate of the plurality of hydraulic pumps, and calculates a required pump number value of each of the plurality of hydraulic actuators according to the required flow rate A connection order storage unit that stores a plurality of priority tables that define the priority of the connection relation of the plurality of hydraulic pumps to one hydraulic actuator of the plurality of hydraulic actuators, and a priority table used for calculation. The change interval time storage unit storing the change interval time, the plurality of priority tables from the connection order storage unit, and the interval time from the change interval time storage unit are fetched and timed to reach the interval time. Connection order changing unit that changes the priority table to be output, and the requested flow rate and request from the requested pump calculation unit The number of pumps and the priority table output by the connection order changing unit, and based on the requested pump number value, calculates the allocation of the plurality of hydraulic pumps to the plurality of hydraulic actuators, and calculates the calculated allocation. And a use pump computing unit that outputs command signals for the plurality of regulators and the plurality of switching valves.

  According to the present invention, the lifespan of each hydraulic pump can be averaged without performing data measurement regarding the operation of each hydraulic pump and calculation of the accumulated work amount. As a result, since the maintenance time of the work machine can be reduced, it is possible to prevent a reduction in the operation rate of the work machine.

1 is a side view showing a hydraulic excavator provided with an embodiment of a drive device for a work machine according to the present invention. It is the schematic which shows one Embodiment of the drive device of the working machine of this invention. It is a table | surface figure which shows an example of the table which prescribed | regulated the priority of the connection relation of the hydraulic pump and hydraulic actuator in one Embodiment of the drive device of the working machine of this invention. It is the schematic which shows the structure of the controller which comprises one Embodiment of the drive device of the working machine of this invention. It is a characteristic view which shows an example of the calculation of the boom request | requirement flow volume in the request | requirement pump calculating part of the controller which comprises one Embodiment of the drive device of the working machine of this invention. It is a characteristic view which shows an example of the calculation of the arm request | requirement flow volume in the request | requirement pump calculating part of the controller which comprises one Embodiment of the drive device of the working machine of this invention. It is a characteristic view which shows an example of the calculation of the boom request | requirement pump number in the request | requirement pump calculating part of the controller which comprises one Embodiment of the drive device of the working machine of this invention. It is a characteristic view which shows an example of the calculation of the arm request | requirement pump number in the request | requirement pump calculating part of the controller which comprises one Embodiment of the drive device of the working machine of this invention. It is a table | surface figure which shows the other example of the table which prescribed | regulated the priority of the connection relationship of the hydraulic pump and hydraulic actuator in one Embodiment of the drive device of the working machine of this invention. It is the schematic which shows the operation | movement of the connection change of the hydraulic pump and hydraulic actuator in one Embodiment of the drive device of the working machine of this invention.

  Embodiments of a drive device for a work machine according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view showing a hydraulic excavator provided with an embodiment of a drive device for a work machine according to the present invention, and FIG. 2 is a schematic view showing an embodiment of the drive device for a work machine according to the present invention. In FIG. 1, a hydraulic excavator 100 includes a lower traveling body 1C provided with a crawler type traveling device, and an upper revolving body 1B provided on the lower traveling body 1C via a turning device so as to be capable of turning. A cabin 103 on which an operator gets on is disposed on the upper swing body 1B. In addition, a base end portion of the front working device 1A is rotatably attached to the front side of the upper swing body 1B.

  The front working device 1A has an articulated structure having a boom 1, an arm 2, and a bucket 3. The boom 1 is rotated up and down with respect to the upper swing body 1B by expansion and contraction of the boom cylinder 4, and the arm 2 is an arm cylinder. The bucket 3 is rotated up and down and front and rear with respect to the boom 1 by the expansion and contraction of 5, and the bucket 3 is rotated up and down and front and rear with respect to the arm 2 by expansion and contraction of the bucket cylinder 6. The turning device is driven by a turning motor 7.

  Next, the system configuration of the driving device in the schematic diagram shown in FIG. 2 will be described. Here, a drive device that drives the boom cylinder 4, the arm cylinder 5, the bucket cylinder 6, and the turning motor 7 will be described as an example. Relief valves, flushing valves, return circuits, load check valves and the like that are not directly related to the present embodiment are omitted for the sake of simplicity.

  In FIG. 2, the drive shaft of the engine 8 that is a power source is connected to a power transmission device 9 that distributes power. The power transmission device 9 includes a first hydraulic pump 10a, a second hydraulic pump 10b, a third hydraulic pump 10c, and a fourth hydraulic pump 10d, which are closed circuit pumps and are both tilt variable displacement hydraulic pumps. And are connected.

  The first hydraulic pump 10a to the fourth hydraulic pump 10d are each a tilting swash plate mechanism having a pair of input / output ports as flow rate adjusting means, and a regulator for adjusting the displacement of the pump by adjusting the tilt angle of the swash plate. 10ax, 10bx, 10cx, 10dx. The regulators 10ax, 10bx, 10cx, and 10dx control the discharge flow rates of the first hydraulic pump 10a to the fourth hydraulic pump 10d, respectively, according to the pump discharge flow rate command value received from the controller 15 via the communication line.

  The discharge port of the first hydraulic pump 10a is connected to switching valves 11a, 11b, 11c, and 11d as flow path switching circuits via the flow path 20 or the flow path 21. The switching valves 11a, 11b, 11c, and 11d are controlled to be in a blocked state when there is no signal, by controlling the flow and blocking of the flow path by a signal from the controller 15 via the control signal line.

  The switching valve 11a is connected to the boom cylinder 4 via the flow paths 40, 41. When the switching valve 11a is in a flow state, the first hydraulic pump 10a is connected to the boom cylinder 4 and the flow paths 20, 21, 40, 41. Connected through.

  The switching valve 11b is connected to the arm cylinder 5 via the flow paths 42 and 43. When the switching valve 11b is in a flow state, the first hydraulic pump 10a is connected to the arm cylinder 5 and the flow paths 20, 21, 42, and 43. Connected through.

  The switching valve 11c is connected to the bucket cylinder 6 via the flow paths 44 and 45. When the switching valve 11c is in a flow state, the first hydraulic pump 10a is connected to the bucket cylinder 6 and the flow paths 20, 21, 44, and 45. Connected through.

  The switching valve 11d is connected to the turning motor 7 via the flow paths 46, 47. When the switching valve 11d is in a flow state, the first hydraulic pump 10a is connected to the turning motor 7 and the flow paths 20, 21, 46. , 47 are connected.

  Similarly, the discharge port of the second hydraulic pump 10b is connected to the switching valves 11e, 11f, 11g, and 11h as the flow path switching circuit via the flow path 22 or the flow path 23, and the discharge port of the third hydraulic pump 10c. Is connected to switching valves 11i, 11j, 11k, and 11l as flow path switching circuits via the flow path 24 or 25, and the discharge port of the fourth hydraulic pump 10d is connected to the flow path 26 or the flow path 27. Are connected to switching valves 11m, 11n, 11o, and 11p as flow path switching circuits. These switching valves 11e to 11p are controlled to flow and shut off in the flow path by a signal from the controller 15 via a control signal line, and to be shut off when there is no signal.

  Similarly, the switching valves 11e, 11i, and 11m are connected to the boom cylinder 4 via the flow paths 40 and 41, and the switching valves 11f, 11j, and 11n are connected to the arm cylinder 5 via the flow paths 42 and 43. It is connected. The switching valves 11g, 11k, and 11o are connected to the bucket cylinder 6 through flow paths 44 and 45, and the switching valves 11h, 11l, and 11p are connected to the turning motor 7 through the flow paths 46 and 47. It is connected.

  Further, the drive device in the present embodiment includes operation lever type operation devices 16 a and 16 b connected to the controller 15 as operation members. The up / down operation of the operation lever of the operation device 16a corresponds to the operation of the boom cylinder 4, and the left / right operation of the operation lever of the operation device 16a corresponds to the operation of the bucket cylinder 6. Similarly, the up / down operation of the operating lever of the operating device 16b corresponds to the operation of the arm cylinder 5, and the left / right operation of the operating lever of the operating device 16b corresponds to the operation of the turning motor 7. The controller 15 calculates the required flow rates of the boom cylinder 4, the arm cylinder 5, the bucket cylinder 6, and the turning motor 7 according to the operation amount of the operation lever of the operating devices 16 a and 16 b, and according to the required flow rate, respectively. A required pump calculating unit for calculating the required number of pumps, and switching of the switching valves 11a to 11p and the first hydraulic pumps 10a to 4 based on information such as the operation amount of the operating lever from the operating devices 16a and 16b. The flow rate of the hydraulic pump 10d is controlled.

  Next, an outline of the operation in the present embodiment will be described with reference to FIGS. FIG. 3 is a table showing an example of a table defining the priority of the connection relationship between the hydraulic pump and the hydraulic actuator in the embodiment of the drive device for the work machine according to the present invention.

  For example, when the boom cylinder 4 is extended by pressure oil from the first hydraulic pump 10a, the oil is discharged from the port on the flow path 21 side of the first hydraulic pump. At this time, the port and the head side oil chamber of the boom cylinder 4 are connected by switching the switching valve 11a on the flow path between the first hydraulic pump 10a and the boom cylinder 4 to the flow state. Then, the return oil from the rod side oil chamber of the boom cylinder 4 is sucked from the other port of the first hydraulic pump 10a.

  In this way, except for a transitional state such as changing the connection destination of the hydraulic pump, a certain hydraulic pump is connected to one hydraulic actuator, so there is no loss due to the diversion using a throttle valve as in the past, and energy saving effect Is obtained. In the hydraulic system in which the connection and change between the hydraulic pump and the hydraulic actuator are repeated in this way, a certain rule is required for the connection and change.

  In the present embodiment, as shown in FIG. 3 as an example, the order in which each hydraulic pump is connected to each hydraulic actuator, and a table indicating the arrangement of the number of hydraulic pumps in the combined operation (the hydraulic pump and the hydraulic actuator are arranged). A table defining the priority of connection relation (hereinafter referred to as a priority table) is used as a rule, and is changed to another priority table at a preset time interval.

  For example, when only the boom cylinder 4 is operated, when the operation lever of the operation device 16a is operated, the first hydraulic pump 10a having the priority of the boom row of FIG. When the operating lever operating amount of the operating device 16a exceeds the increasing threshold value, the second hydraulic pump 10b having a priority of 2 is connected to the boom cylinder 4, and the operating lever operating amount of the operating device 16a is further increased. When increased, the third hydraulic pump 10c having a priority of 3 is connected to the boom cylinder 4, and when the operation lever operation amount of the operating device 16a is further increased, the fourth hydraulic pump 10d having a priority of 4 is connected to the boom cylinder. 4 is connected. Similarly, when only the arm cylinder 5 is operated, as the operation lever operation amount of the operation device 16b is increased, the hydraulic pumps are the second hydraulic pump 10b, the fourth hydraulic pump 10d, the first hydraulic pump 10a, the first hydraulic pump. Three hydraulic pumps 10c are connected to the arm cylinder 5 in this order.

  Further, under the state where all four hydraulic pumps 10a to 10d are connected to the arm cylinder 5, when the combined operation of operating the operation lever of the operation device 16a to increase the operation amount of the boom cylinder 4 is performed, The use of the first hydraulic pump 10a whose priority in the boom row of FIG. 3 is 1 is required.

  However, since the first hydraulic pump 10a is already connected to the arm cylinder 5, the number of pumps is distributed according to priority. That is, the first hydraulic pump 10a has a priority of 3 for the arm cylinder 5, whereas the priority for the boom cylinder 4 is 1. As a result, the first hydraulic pump 10 a is disconnected from the arm cylinder 5 and reconnected to the boom cylinder 4.

  Thereafter, when the operation amount of the boom cylinder 4 is further increased, the third hydraulic pump 10 c is disconnected from the arm cylinder 5 and reconnected to the boom cylinder 4. However, since the priority of the second hydraulic pump 10b is 1 in the arm cylinder 5 and higher than 2 in the direction of the boom cylinder 4, the second hydraulic pump 10b remains connected to the arm cylinder 5. Similarly, the priority of the fourth hydraulic pump 10d is 2 in the arm cylinder 5 and higher than 4 in the direction of the boom cylinder 4, so that the fourth hydraulic pump 10d remains connected to the arm cylinder 5.

  As described above, the controller 15 appropriately distributes the number of hydraulic pumps using the priority of connection, so that each hydraulic actuator can be stably operated even during the combined operation.

  In the priority table shown in FIG. 3, all hydraulic pumps (first hydraulic pump 10a to fourth hydraulic pump 10d) are all hydraulic actuators (boom cylinder 4 and arm cylinder 5) by a flow path switching circuit (switching valve). The bucket cylinder 6 and the turning motor 7) are applied on condition that they can be switched and connected equally. For example, the first hydraulic pump 10 a to the third hydraulic pump 10 c can be connected only to the boom cylinder 4, the arm cylinder 5, and the bucket cylinder 6, and the fourth hydraulic pump can be connected only to the turning motor 7. In the case of a system in which a path switching circuit (switching valve) is formed, a priority table in which the column of the turning motors in FIG. 3 is deleted may be used.

  Next, the configuration of the controller in the present embodiment will be described with reference to FIGS. FIG. 4 is a schematic diagram showing a configuration of a controller constituting one embodiment of a drive device for a work machine according to the present invention, and FIG. 5A is a request pump of a controller constituting one embodiment of a drive device for a work machine according to the present invention. FIG. 5B is a characteristic diagram showing an example of the calculation of the boom required flow rate in the calculation unit, and FIG. 5B shows an example of the calculation of the arm required flow rate in the request pump calculation unit of the controller constituting one embodiment of the drive device for the work machine of the present invention. FIG. 6A is a characteristic diagram, FIG. 6A is a characteristic diagram showing an example of calculation of the number of requested boom pumps in the requested pump calculation unit of the controller constituting the embodiment of the drive device for the work machine of the present invention, and FIG. 6B is the work machine of the present invention. FIG. 7 is a characteristic diagram showing an example of calculation of the number of arm request pumps in the request pump calculation unit of the controller that constitutes an embodiment of the drive device according to the present invention. It is a table showing another example of a table defining the priority of the connection relationship between the hydraulic pump and the hydraulic actuator in the embodiment of the driving device.

  As shown in FIG. 4, the controller 15 includes a request pump calculation unit 30 that calculates the number of required pumps according to the operation lever operation amount of the operation devices 16a and 16b, and the priority of the connection relationship between the hydraulic pump and the hydraulic actuator. A change interval time storage unit 31 for storing an interval for changing from a plurality of priority tables to other priority tables different from the current priority table, a connection order storage unit 32 for storing the plurality of priority tables, and a change The signal from the interval time storage unit 31 and the signal from the connection order storage unit 32 are input, and the signal from the request pump calculation unit 30 and the connection order change unit 33 that changes the priority table at the interval time set by timing. And the signal from the connection order changing unit 33 is input, and the allocation of the hydraulic pump to the hydraulic actuator is calculated based on the requested pump number signal. Based on the allocation result, and a use pumping operation unit 34 for outputting a command signal for the regulator 10ax~10dx and each switching valve 11a~11p of the hydraulic pumps.

  The requested pump calculation unit 30 inputs operation lever operation amount signals for the respective hydraulic actuators from the operation devices 16a and 16b, and requests flow rates for the respective hydraulic actuators (the number of hydraulic pumps as a ratio to the rated flow rate of the hydraulic pumps). And the required number of pumps. As shown in FIGS. 5A and 5B, the required flow rate (for each) is determined by the operation lever operation amount of the operation devices 16a and 16b. For example, it is assumed that the operation amounts of the boom cylinder 4 and the arm cylinder 5 are 20% and 30% of the total operation amount at a certain time, respectively. 5A and 5B, the required flow rate is 0.8 hydraulic pumps with the rated flow rate of the boom cylinder 4 and 1.2 hydraulic pumps with the rated flow rate of the arm cylinder 5. The required flow rate signal is output to the used pump computing unit 34.

  As shown in FIGS. 6A and 6B, the required number of pumps is determined by the required flow rate (for each) of the hydraulic actuator. As described above, in the present embodiment, since one hydraulic pump is not connected to a plurality of hydraulic actuators, the boom cylinder 4 and the arm cylinder 5 do not overlap each other and request a hydraulic pump. In the case of the operation amount described above, according to the characteristic diagrams defined in FIGS. 6A and 6B, the required number of pumps for the required flow rate (for each) is one for the boom cylinder 4 and two for the arm cylinder 5. The signal is output to the used pump calculation unit 34.

  Returning to FIG. 4, the change interval time storage unit 31 stores an interval for changing to another priority table different from the current priority table. For example, one week (154 hours) can be set. A signal from the change interval time storage unit 31 is input to the connection order change unit 33.

  The connection order storage unit 32 stores a plurality of priority tables. In the present embodiment, the first priority table shown in FIG. 3 and the second priority table shown in FIG. 7 are stored. A signal from the connection order storage unit 32 is input to the connection order change unit 33.

  The connection order changing unit 33 takes in the interval time signal for changing the priority table from the change interval time storage unit 31, and the first priority table signal and the second priority table signal from the connection order storage unit 32, The priority table signal to be output is changed at the interval time set by timing. A signal from the connection order changing unit 33 is input to the used pump calculating unit 34.

  The used pump computing unit 34 takes in the requested flow rate signal, the requested pump number signal from the requested pump computing unit 30, and the priority table signal from the connection order changing unit 33, and based on the requested pump number signal, the hydraulic pressure of the hydraulic pump The allocation to the actuator is calculated, and command signals for the regulators 10ax to 10dx and the switching valves 11a to 11p of each hydraulic pump are output based on the allocation result.

  Next, the operation of the embodiment of the working machine drive device of the present invention will be described with reference to FIG. FIG. 8 is a schematic diagram showing the operation of changing the connection between the hydraulic pump and the hydraulic actuator in one embodiment of the drive device for the work machine of the present invention.

  In FIG. 8, the horizontal axis indicates time, and the vertical axis indicates (a) boom operation lever input, (b) arm operation lever input, (c) boom requested flow rate, (d) arm requested flow rate, (e) (F) Second hydraulic pump flow rate (for the number of pumps) and connection destination, (g) Third hydraulic pump flow rate (for the number of pumps) and connection destination, (h) ) The fourth hydraulic pump flow rate (for the number of pumps) and the connection destination are shown. The time t1 is the time when the operation amount of the boom operation lever is 20% of the total operation amount and the operation amount of the arm operation lever is 30% of the total operation amount. The time t2 is the change interval time storage unit 31. Each time when the stored change time is reached is shown. The first priority table is used from time t1 to time t2, and the second priority table is used after time t2.

  First, at time t1, assuming that the operation amount of the boom operation lever is 20% of the total operation amount and the operation amount of the arm operation lever is 30% of the total operation amount, as shown in FIGS. The operation lever operation amount signals for the respective hydraulic actuators are input to the request pump calculation unit 30 from 16a and 16b. 5A and 5B, the required flow rate is equivalent to 0.8 hydraulic pumps with the rated flow rate of the boom cylinder 4 and 1.2 hydraulic pumps with the rated flow rate of the arm cylinder 5. The results are shown in (c) and (d).

  The required pump calculation unit 30 calculates the required number of pumps with respect to the required flow rate according to the characteristic diagrams defined in FIGS. 6A and 6B based on the required flow rate. One boom cylinder 4 and two arm cylinders 5 are provided.

  The used pump calculation unit 34 shown in FIG. 4 inputs a request flow rate signal and a request pump number signal from the request pump calculation unit 30. On the other hand, since the first priority table is set from time t1 to time t2, the signal of the first priority table shown in FIG.

  As a result, the used pump computing unit 34 performs allocation according to the first priority table, outputs a command to the switching valve 11a to connect the first hydraulic pump 10a to the boom cylinder 4, and is equivalent to 0.8 units. A command to the regulator 10ax is output so that the flow rate can be supplied. Further, a command to the switching valve 11f is output so as to connect the second hydraulic pump 10b to the arm cylinder 5, and a command to the regulator 10bx is output so that the flow rate for one can be supplied. The results are shown in FIGS. 8 (e) and (f). In addition, the used pump calculation unit 34 outputs a command to the switching valve 11n so that the fourth hydraulic pump 10d is connected to the arm cylinder 5, and a command to the regulator 10dx so that a flow rate of 0.2 can be supplied. Is output. The third hydraulic pump 10c is not connected to any hydraulic actuator, and the flow rate is zero. The results are shown in FIGS. 8 (h) and (g).

  Next, under this state, when the time t2, which is the change time stored in the change interval time storage unit 31, is reached, the interval time for changing the priority table in the connection order change unit 33 in FIG. 4 has been reached. Therefore, the connection order changing unit 33 outputs the second priority table to the use pump calculating unit 34 instead of the first priority table.

  In the used pump calculation unit 34, the request flow rate signal from the request pump calculation unit 30 and the request pump number signal do not change, but the priority table from the connection order changing unit 33 is switched. I do. Specifically, based on the second priority table shown in FIG. 7, a command to the switching valve 11b is output to connect the first hydraulic pump 10a to the arm cylinder 5, and a flow rate of 0.2 is supplied. A command to the regulator 10ax is output so that it can be performed. Further, a command to the switching valve 11e is output so that the second hydraulic pump 10b is connected to the boom cylinder 4, and a command to the regulator 10bx is output so that a flow rate of 0.8 can be supplied. The results are shown in FIGS. 8 (e) and (f).

  Moreover, the used pump calculating part 34 outputs the instruction | command to the switching valve 11j so that the 3rd hydraulic pump 10c may be connected to the arm cylinder 5, and outputs the instruction | command to the regulator 10cx so that the flow volume for one piece can be supplied. To do. The fourth hydraulic pump 10d is not connected to any hydraulic actuator, and the flow rate is zero. The results are shown in FIGS. 8 (g) and (h).

In the present embodiment described above, between time t1 and time t2 in FIG. 8, as shown in (e) to (h), the discharge flow rate and the discharge pressure of each hydraulic pump are different. There is a difference in degree.
In a general work machine, when such a repetitive operation in which the required flow rate of the hydraulic pump is almost the same is performed, the connection relationship between the hydraulic pump and the hydraulic actuator is almost fixed, and a difference in the degree of wear is accumulated. As a result, a large individual difference occurs in the remaining life of the hydraulic pump. Therefore, it is necessary to appropriately change the connection relationship between the hydraulic pump and the hydraulic actuator.

  Here, for example, the work of hydraulic pumps (= pressure x flow rate x operating time) is calculated for each hydraulic pump, and the connection order is changed between the hydraulic pumps so as to average the accumulated work by accumulating the work. It is possible to do. In this case, the error of the measuring means becomes a problem. That is, when there is an error in at least one of the pressure measuring means and the flow rate measuring means of a certain hydraulic pump, the accumulated error is added to the accumulated work amount of the hydraulic pump. Therefore, it is difficult to accurately estimate the accumulated work amount, and it becomes difficult to average the accumulated work amount.

  In the present embodiment, the priority of the connection relationship between the hydraulic pump and the hydraulic actuator is set at a constant change time interval stored in the change interval time storage unit 31 without using the information obtained by such measurement means. Change the specified table. In the present embodiment, as shown in FIG. 8, at the time t2, the first priority table is changed to the second priority table, and the connection destination and flow rate of each hydraulic pump are changed. In this way, the connected hydraulic pumps can be replaced while securing the same supply flow rate of each hydraulic actuator as before the change after time t2.

  In the present embodiment, since the measuring means for measuring the pressure and the flow rate is not used, it is possible to accurately average the degree of wear of the hydraulic pump without being affected by the measurement error.

  In addition, as a method for changing the connection order of the hydraulic pump and the hydraulic actuator, it is only necessary to change between hydraulic pumps having the same connectable hydraulic actuator. Therefore, the flow path switching circuit as described in this embodiment ( All the hydraulic pumps (the first hydraulic pump 10a to the fourth hydraulic pump 10d) can be connected to all the hydraulic actuators (the boom cylinder 4, the arm cylinder 5, the bucket cylinder 6, and the turning motor 7) by the switching valve. It is not limited to cases.

  For example, the first hydraulic pump 10a to the third hydraulic pump 10c, which are a part of all the hydraulic pumps, can be equally connected to the boom cylinder 4, the arm cylinder 5, and the bucket cylinder 6 that are a part of all the hydraulic actuators. In the case of a system in which the fourth hydraulic pump can be connected only to the turning motor 7, the first hydraulic pump 10a to the third hydraulic pump 10c and the boom cylinder 4, the arm cylinder 5 and the bucket cylinder 6 are connected. Is provided with a flow path switching circuit (switching valve), and a table defining the priority of the connection relationship between them is stored in the connection order storage unit 32. Accordingly, it is sufficient that the connection order based on the priority table can be changed only between them.

  Further, when measuring the interval time by the change interval time storage unit 31, the engine operating time of the work machine may be used, for example, the operation time of the operation devices 16a and 16b, or the pressure oil at which each hydraulic pump is equal to or higher than a predetermined pressure. Any time may be used as long as it is related to the operation of the work machine, such as the accumulation of the time when the gas is discharged.

  Further, when the connection order is changed, in addition to the fact that the change time stored in the change interval time storage unit 31 has been reached, the connection is made when the operation amount of the operation devices 16a and 16b is zero, that is, when no operation is performed. A condition for executing the order change may be added. Specifically, the operation amount signals from the operation devices 16a and 16b are input to the connection order changing unit 33, and the connection order changing unit 33 counts the time interval and the operation amount of the operation device is zero. When the condition is satisfied, the process of changing the priority table to be output may be executed. As a result, it is possible to prevent an abrupt change in operational feeling due to a change in the hydraulic pump used when operating the operating devices 16a and 16b.

  In addition, in the operation site of the ultra-large hydraulic excavator for a mine shown in FIG. 1, it is common to provide a downtime periodically in order to replenish hydraulic oil or replace engine oil. Therefore, the priority table may be changed at the timing of these pause times.

  According to the embodiment of the drive device for a work machine of the present invention described above, the life of each hydraulic pump can be averaged without performing data measurement regarding the operation of each hydraulic pump and calculation of the accumulated work amount. As a result, since the maintenance time of the work machine can be reduced, it is possible to prevent a reduction in the operation rate of the work machine.

  In the present embodiment, the description has been made based on the drive device including only the closed circuit pump, but the present invention is not limited to this. A drive device with an open circuit pump can be averaged as well.

  Further, the above-described embodiment has been described in detail for easy understanding of the present invention, and is not necessarily limited to one having all the configurations described.

  DESCRIPTION OF SYMBOLS 1A ... Front working device, 1B ... Upper turning body, 1C ... Lower traveling body, 1 ... Boom, 2 ... Arm, 3 ... Bucket, 4 ... Boom cylinder, 5 ... Arm cylinder, 6 ... Bucket cylinder, 7 ... Turning motor , 8 ... Engine, 9 ... Power transmission device, 10a to d ... First to fourth hydraulic pumps (closed circuit pump), 10ax to dx ... Regulator, 11a to p ... Switching valve, 15 ... Controller, 16a, b ... Operation device (Operation member), 30 ... request pump calculation unit, 31 ... change interval time storage unit, 32 ... connection order storage unit, 33 ... connection order change unit, 34 ... used pump calculation unit, 100 ... hydraulic excavator.

Claims (5)

An operation member operated by an operator;
Multiple hydraulic pumps,
A plurality of regulators for controlling discharge flow rates of the plurality of hydraulic pumps;
A plurality of hydraulic actuators connected to the plurality of hydraulic pumps by flow paths;
Provided respectively on flow paths connecting the plurality of hydraulic pumps and the plurality of hydraulic actuators, and one hydraulic pump of the plurality of hydraulic pumps can be connected to one hydraulic actuator of the plurality of hydraulic actuators A plurality of switching valves,
A drive device for a work machine, comprising: a controller that outputs a command signal for controlling the plurality of regulators and the plurality of switching valves;
The controller calculates a required flow rate of each of the plurality of hydraulic actuators as a ratio with a rated flow rate of the plurality of hydraulic pumps according to an operation amount of the operation member, and the plurality of hydraulic actuators according to the required flow rate A request pump calculation unit for calculating the respective request pump number values of
A connection order storage unit in which a plurality of priority tables defining the priority of the connection relation of the plurality of hydraulic pumps to one hydraulic actuator among the plurality of hydraulic actuators are stored;
A change interval time storage unit in which an interval time for changing the priority table used for calculation is stored;
A connection order change unit that takes in a plurality of priority tables from the connection order storage unit and an interval time from the change interval time storage unit, and changes the priority table to be output when the interval time is reached by timing. When,
The plurality of hydraulic actuators of the plurality of hydraulic pumps are fetched based on the requested pump number value based on the requested flow rate, the requested pump number value from the requested pump calculation unit, and the priority table output by the connection order changing unit. A calculation unit to calculate, based on the calculated allocation, comprising a use pump arithmetic unit that outputs a command signal to the plurality of regulators and the plurality of switching valves,
A drive device for a working machine. In the work machine drive device according to claim 1,
The plurality of switching valves are respectively disposed on flow paths connecting the plurality of hydraulic pumps and the plurality of hydraulic actuators so that all of the plurality of hydraulic pumps can be equally connected to all of the plurality of hydraulic actuators. A drive device for a work machine, characterized by being provided. In the work machine drive device according to claim 1,
The plurality of switching valves are configured so that a part of the plurality of hydraulic pumps can be connected to a part of the plurality of hydraulic actuators equally. A working machine drive device characterized in that each of the hydraulic pumps is provided on a flow path connecting a part of the hydraulic pumps and a part of the plurality of hydraulic actuators. In the drive device of the working machine according to claim 3,
The priority table stored in the connection order storage unit indicates a priority of a connection relationship between a part of the plurality of hydraulic pumps and a part of the plurality of hydraulic actuators. A drive device for a work machine characterized by being specified. The drive device for a work machine according to any one of claims 1 to 4,
The connection order change unit takes in a plurality of priority tables from the connection order storage unit, an interval time from the change interval time storage unit, and an operation amount of the operation member, and counts to reach the interval time. When the condition that the amount of operation of the operation member is zero is satisfied, the priority table to be output is changed.

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