Output control device, method, and program

Abstract

To provide an output control device that can effectively utilize the output horsepower from a power source in a hydraulic fluid discharge device. [Solution] The output control device 82 is an output control device 82 for adjusting the output from a hydraulic fluid discharge device 34 driven by a power source 12 that outputs at a predetermined horsepower, and comprises a hydraulic pressure acquisition unit 88 that acquires the hydraulic pressure detected by hydraulic pressure detection devices 72a, 72b that detect the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device 34, and an output control unit 86 that adjusts the output from the hydraulic fluid discharge device 34 by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device 34 based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit 88.

Description

[Technical Field]

[0001] The present invention relates to an output control device, method, and program for controlling the output from a hydraulic fluid discharge device. [Background technology]

[0002] In work vehicles and the like, a hydraulic fluid discharge device is used that is driven by a power source that outputs a predetermined horsepower and discharges hydraulic fluid to supply it to a hydraulic drive system. For the hydraulic fluid discharge device, a target horsepower that the hydraulic fluid discharge device should output is set from the output horsepower of the power source. If the horsepower output from the hydraulic fluid discharge device, i.e., the absorbed horsepower, exceeds the target horsepower, the power source may stop, so the absorbed horsepower of the hydraulic fluid discharge device must be less than the target horsepower. For this reason, the hydraulic fluid discharge device is configured so that the flow rate is set in accordance with the hydraulic pressure, so that the absorbed horsepower of the hydraulic fluid discharge device is less than the target horsepower but close to the target horsepower. Furthermore, when other drive systems are driven by the power source, the target horsepower that the hydraulic fluid discharge device should output is changed according to the horsepower output from the other drive systems, so the hydraulic fluid discharge device is configured so that the absorbed horsepower of the hydraulic fluid discharge device is less than the changed target horsepower by changing the flow rate set in accordance with the hydraulic pressure (see, for example, Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 6-108497 [Overview of the project] [Problems that the invention aims to solve]

[0004] Although the flow rate of the hydraulic fluid discharge system is set in accordance with the hydraulic pressure, the absorbed horsepower of the hydraulic fluid discharge system is not set to perfectly follow the target horsepower. Therefore, if the flow rate set in the hydraulic fluid discharge system is changed in accordance with the hydraulic pressure so that the absorbed horsepower of the hydraulic fluid discharge system becomes smaller than the changed target horsepower across the entire range of expected hydraulic pressure, then, depending on the hydraulic pressure, the absorbed horsepower of the hydraulic fluid discharge system will be far from the target horsepower, and the output horsepower from the power source will not be effectively utilized.

[0005] The object of the present invention is to provide an output control device, method, and program that can effectively utilize the output horsepower from a power source in a hydraulic fluid discharge device. [Means for solving the problem]

[0006] One aspect of the present invention is an output control device for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, comprising: a hydraulic pressure acquisition unit that acquires hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control unit that adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit.

[0007] Another aspect of the present invention is an output control method for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, comprising: an oil pressure acquisition step of acquiring an oil pressure detected by an oil pressure detection device that detects the oil pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control step of adjusting the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the oil pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the oil pressure acquired in the oil pressure acquisition step.

[0008] A further aspect of the present invention is an output control program for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, wherein the program enables a computer to implement: a hydraulic pressure acquisition function that acquires hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control function that adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the hydraulic pressure acquired by the hydraulic pressure acquisition function. [Effects of the Invention]

[0009] In this invention, it is possible to effectively utilize the output horsepower from the power source in a hydraulic fluid discharge device. [Brief explanation of the drawing]

[0010] [Figure 1] A block diagram showing a work vehicle of one embodiment of the present invention. [Figure 2] A graph illustrating the principle of output control in one embodiment of the present invention. [Figure 3] A flowchart illustrating the output control method of one embodiment of the present invention. [Figure 4] A block diagram showing the hardware configuration of the controller in one embodiment of the present invention. [Modes for carrying out the invention]

[0011] An embodiment of the present invention will be described below with reference to Figures 1 to 4.

[0012] The hydraulic excavator 10, which serves as a work vehicle in this embodiment, will be described with reference to Figures 1 and 2.

[0013] As shown in Fig. 1, a hydraulic excavator 10 includes an engine 12 serving as a power source, an air conditioner compressor 14 serving as a drive device, a hydraulic oil supply system 30, and various hydraulic drive devices 16. The compressor 14 and the hydraulic oil supply system 30 are driven by the engine 12 that outputs power at a predetermined horsepower, and the various hydraulic drive devices 16 are driven by hydraulic oil supplied from the hydraulic oil supply system 30.

[0014] In the present embodiment, the air conditioner compressor 14 is driven by the engine 12; however, instead of or in addition to the air conditioner compressor 14, any drive device may be driven by the engine 12.

[0015] The hydraulic oil supply system 30 includes a pump unit 32, an output control system 40, and a control valve 18. The output control system 40 includes a flow rate adjustment mechanism 42 serving as a flow rate adjustment device, a pressure reducing valve 62 serving as an output changing device, first to third hydraulic pressure sensors 72a, 72b, 72c serving as hydraulic pressure detection devices, and a controller 82 serving as an output control device.

[0016] The pump unit 32 includes a main pump 34 serving as a first hydraulic oil discharge device, a sub pump 38 serving as a second hydraulic oil discharge device, and a pilot pump 36. The main pump 34, the sub pump 38, and the pilot pump 36 are driven by the engine 12.

[0017] The main pump 34 discharges hydraulic oil at an equal discharge flow rate Q from a first discharge port and a second discharge port. The main pump 34 supplies hydraulic oil from the first and second discharge ports to the various hydraulic drive devices 16 via the first and second supply flow paths 22a, 22b and the control valve 18. For example, hydraulic oil is supplied from the first discharge port of the main pump 34 to a boom cylinder of a boom, a bucket cylinder of a bucket, and a left travel motor of a crawler travel device, and is supplied from the second discharge port to a right travel motor of the crawler travel device, an arm cylinder of an arm, and a service port.

[0018] When the engine 12 drives drive devices other than the main pump 34, the output horsepower from the engine 12 must be distributed to the output of the drive devices other than the main pump 34, thus limiting the output horsepower that can be distributed to the main pump 34. In contrast, for the main pump 34, a target horsepower is set from the output horsepower of the engine 12 that the main pump 34 should output. If the horsepower output from the main pump 34, i.e., the absorbed horsepower, exceeds the target horsepower, the engine 12 may stall, so the absorbed horsepower of the main pump 34 is kept below the target horsepower.

[0019] In other words, in the main pump 34, the absorbed horsepower is determined by the product of the sum of the first and second discharge hydraulic pressures P1 and P2 of the hydraulic fluid discharged from the first and second discharge ports, and the discharge flow rate Q of the hydraulic fluid discharged from the first and second discharge ports. Then, in the main pump 34, the discharge flow rate Q is set by the flow rate adjustment mechanism 42 to correspond to the sum of the first and second discharge hydraulic pressures P1 and P2, thereby making the absorbed horsepower of the main pump 34 smaller than the target horsepower and close to the target horsepower.

[0020] Specifically, the flow rate adjustment mechanism 42 includes a swash plate 44 as a flow rate adjustment member, a biasing mechanism 48, a pilot port 56c, a flow path 54d, and a port 56d. In the main pump 34, the discharge flow rate Q of the hydraulic fluid discharged from the first and second discharge ports increases or decreases by increasing or decreasing the inclination angle of the swash plate 44. The swash plate 44 is biased by the biasing force of the biasing mechanism 48 in the direction that increases the inclination angle, that is, in the direction that increases the discharge flow rate Q. On the other hand, the swash plate 44 is pressed in the direction that decreases the inclination angle, that is, in the direction that decreases the discharge flow rate Q of the main pump 34, by the sum of the first and second discharge hydraulic pressures P1 and P2 of the hydraulic fluid discharged from the first and second discharge ports of the main pump 34. Furthermore, when the sum of the first and second discharge hydraulic pressures P1 and P2 increases or decreases, the tilt angle of the swash plate 44 decreases or increases, either due to the biasing force of the biasing mechanism 48 by the total hydraulic pressure P or by the biasing force of the biasing mechanism 48 against the hydraulic pressure of the total hydraulic pressure P, and the discharge flow rate Q of the main pump 34 decreases or increases. The biasing force of the biasing mechanism 48 is set so that, over the entire range of the assumed total hydraulic pressure P, the absorption horsepower of the main pump 34 is less than the target horsepower and close to the target horsepower.

[0021] In this embodiment, as shown in Figure 2(a), the discharge flow rate Q of the main pump 34 is set according to the characteristic line TO with respect to the target horsepower curve HO of the main pump 34, corresponding to the total hydraulic pressure P of the first and second discharge hydraulic pressures P1 and P2.

[0022] That is, the biasing mechanism 48 has first and second elastic members 52a and 52b. When the total hydraulic pressure P is between 0 and the first reference hydraulic pressure K1, biasing is performed by the first elastic member 52a, and the inclination angle of the swash plate 44 is not increased or decreased against the biasing force of the biasing mechanism 48 by the hydraulic pressure of the total hydraulic pressure P, the inclination angle of the swash plate 44 is maintained at its maximum, and the discharge flow rate Q of the main pump 34 is maintained at its maximum. When the total hydraulic pressure P is between the first reference hydraulic pressure K1 and the second reference hydraulic pressure K2, biasing is performed by the first elastic member 52a, and the inclination angle of the swash plate 44 is decreased or increased against the biasing force of the first elastic member 52a by the hydraulic pressure of the total hydraulic pressure P, or against the hydraulic pressure of the total hydraulic pressure P, and the discharge flow rate Q of the main pump 34 is decreased or increased. When the total hydraulic pressure P is between the second reference hydraulic pressure K2 and the third reference hydraulic pressure K3, biasing is applied by the second elastic member 52b in addition to the first elastic member 52a, and the moving member is moved by the biasing forces of the first and second elastic members 52a and 52b against the biasing force of the first and second elastic members 52a and 52b, or against the hydraulic pressure of the total hydraulic pressure P, thereby decreasing or increasing the inclination angle of the swash plate 44 and decreasing or increasing the discharge flow rate Q of the main pump 34. When the total hydraulic pressure P is greater than or equal to the third reference hydraulic pressure K3, the inclination angle of the swash plate 44 is kept to the minimum, and the discharge flow rate Q of the main pump 34 is kept to the minimum. The biasing forces of the first and second elastic members 52a and 52b of the biasing mechanism 48 are set so that the absorption horsepower of the main pump 34 follows the target horsepower at a level that is less than the target horsepower and close to the target horsepower throughout the entire range of assumed total hydraulic pressure P.

[0023] Therefore, as shown in Figure 2(a), if the starting point X0 and the first, second, and third inflection points X1, X2, and X3 are the points where the total hydraulic pressure P is 0 and the first, second, and third reference hydraulic pressures K1, K2, and K3 are respectively along the characteristic curve TO, then the 0th line segment Y0 from the starting point X0 to the first inflection point X1 extends horizontally, the 1st line segment Y1 from the 1st inflection point X1 to the 2nd inflection point X2 descends at a constant slope, the 2nd line segment Y2 from the 2nd inflection point X2 to the 3rd inflection point X3 descends at a constant slope smaller than the slope of the 1st line segment Y1, and the 3rd line segment Y3 from the 3rd inflection point X3 onward extends horizontally. Then, across the entire range of the assumed total hydraulic pressure P, the characteristic curve TO is positioned to follow the target horsepower curve HO below and near the target horsepower curve HO.

[0024] Referring again to Figure 1, when the hydraulic excavator 10 drives the air conditioner, the output horsepower from the engine 12 must also be distributed to the air conditioner's compressor 14, thus reducing the output horsepower that can be distributed to the main pump 34. For this reason, the target horsepower that the main pump 34 should output is reduced, and the absorption horsepower of the main pump 34 is reduced in accordance with the reduced target horsepower.

[0025] In other words, in the main pump 34, the flow rate adjustment mechanism 42 is operated by the pressure reducing valve 62 to reduce the discharge flow rate Q, which is set in accordance with the total hydraulic pressure P of the first and second discharge hydraulic pressures P1 and P2, thereby making the absorption horsepower of the main pump 34 smaller than the reduced target horsepower (hereinafter also simply referred to as "target horsepower").

[0026] Specifically, the pump unit 32 has a pilot pump 36. The pilot pump 36 supplies pilot oil to the pilot port 56c of the flow rate adjustment mechanism 42 of the main pump 34 via the pilot flow path 54c and the pressure reducing valve 62. The hydraulic pressure of the pilot oil supplied to the pilot port 56c presses the swash plate 44 in a direction that decreases the inclination angle, that is, in a direction that decreases the discharge flow rate Q of the main pump 34. The pressure reducing valve 62 is controlled by a controller 82, which acts as an output control device. In the controller 82, the drive state detection unit 84 detects the drive state of the air conditioner's compressor 14. If the drive state detection unit 84 detects that the compressor 14 is not being driven, the pressure reducing valve control unit 86, which acts as an output control device, does not supply a control current A to the pressure reducing valve 62 and sets the hydraulic pressure of the pilot oil supplied from the pilot pump 36 to the pilot port 56c by the pressure reducing valve 62 to 0. When the drive state detection unit 84 detects that the compressor 14 is being driven, the pressure reducing valve control unit 86 supplies a control current A to the pressure reducing valve 62, increases the hydraulic pressure of the pilot oil supplied from the pilot pump 36 to the pilot port 56c by the pressure reducing valve 62, reduces the inclination angle of the swash plate 44 against the biasing force of the biasing mechanism 48, reduces the discharge flow rate Q of the main pump 34, and reduces the absorption horsepower of the main pump 34.

[0027] In this embodiment, as shown in Figure 2(b), the characteristic line TO for the target horsepower curve HO when the air conditioner compressor 14 is not driven is moved to the leftward characteristic line TD for the target horsepower curve HD when the air conditioner compressor 14 is driven, which is a decrease from the target horsepower curve HO.

[0028] Here, if the control current A supplied to the pressure reducing valve 62 when the compressor 14 is driven is constant, and the hydraulic pressure of the pilot oil supplied to the pilot port 56c by the pressure reducing valve 62 is constant, then over the entire range of the assumed total hydraulic pressure P, it is necessary to ensure that the absorption horsepower of the main pump 34 is less than the target horsepower, that is, that the characteristic curve TD is positioned below the target horsepower curve HD. In this case, since the characteristic curve TD does not perfectly follow the target horsepower curve HD, depending on the total hydraulic pressure P, even though there is room to increase the horsepower by increasing the discharge flow rate Q of the main pump 34 relative to the target horsepower, the main pump 34 will end up outputting at a horsepower lower than the target horsepower, and the output horsepower from the engine 12 will not be utilized to its fullest potential.

[0029] Therefore, in this embodiment, the first and second discharge hydraulic pressures P1 and P2 of the main pump 34 are detected, and based on the total hydraulic pressure P of the detected first and second discharge hydraulic pressures P1 and P2, the pressure reducing valve 62 is controlled to adjust the flow rate adjustment mechanism 42, and the discharge flow rate Q set in the main pump 34 in accordance with the total hydraulic pressure P is adjusted so that the absorption horsepower of the main pump 34 is smaller than the target horsepower and closer to the target horsepower.

[0030] Specifically, referring again to Figure 1, the first and second hydraulic sensors 72a and 72b detect the first and second discharge hydraulic pressures P1 and P2 of the hydraulic fluid discharged from the first and second discharge ports of the main pump 34 and output them to the controller 82. In the controller 82, the hydraulic pressure acquisition unit 88 acquires the detected first and second discharge hydraulic pressures P1 and P2 input from the first and second hydraulic sensors 72a and 72b and acquires the total hydraulic pressure P of the detected first and second discharge hydraulic pressures P1 and P2. The pressure reducing valve control unit 86 sets the target horsepower to be output from the main pump 34 according to the horsepower of the output from the compressor 14 that is distributed to the air conditioner compressor 14 from the output horsepower of the engine 12. Then, the pressure reducing valve control unit 86 sets the target discharge flow rate Q of the main pump 34 to achieve the target horsepower of the main pump 34 based on the total hydraulic pressure P detected by the hydraulic pressure acquisition unit 88. tis acquired, and a control current A supplied to a pressure reducing valve 62 is controlled such that a discharge flow rate Q of a main pump 34 becomes a target discharge flow rate Q t for the detected total hydraulic pressure P. The pressure reducing valve 62 adjusts a pilot hydraulic pressure P supplied to a pilot port 56c in accordance with the supplied control current A c , and adjusts the inclination angle of a swash plate 44 against the biasing force of a biasing mechanism 48 by the pilot hydraulic pressure P c , or adjusts the inclination angle of the swash plate 44 against the hydraulic pressure of the pilot hydraulic pressure P c by the biasing force of the biasing mechanism 48, thereby adjusting the discharge flow rate Q of the main pump 34 to the target discharge flow rate Q t , and adjusting the absorption horsepower of the main pump 34 to a target horsepower.

[0031] In the present embodiment, as shown in FIG. 2(c), by controlling the control current A supplied to the pressure reducing valve 62, a flow rate adjustment mechanism 42 is adjusted, and a characteristic line is moved left and right. Then, for predetermined total hydraulic pressures P', P", the control current A supplied to the pressure reducing valve 62 is controlled such that characteristic lines TC', TC" intersect a target horsepower curve HD at target points R'(P', Q t ') , , R"(P", Q t ") on the target horsepower curve HD where a discharge flow rate Q becomes a target discharge flow rate Q t ', Q t ", respectively.

[0032] Referring again to FIG. 1, a sub-pump 38 supplies hydraulic oil to various hydraulic drive devices 16 through a third supply flow path 22c and via a control valve 18. For example, hydraulic oil is supplied from the sub-pump 38 to a swing motor of an upper revolving superstructure, a swing cylinder of a swing mechanism, and a blade cylinder of a blade.

[0033] The sub-pump 38 has a constant discharge flow rate of hydraulic fluid, and the horsepower output from the sub-pump 38 is determined by the third discharge hydraulic pressure P3 of the hydraulic fluid discharged from the sub-pump 38, and the horsepower fluctuates with fluctuations in the third discharge hydraulic pressure P3. Since the sub-pump 38 is also driven by the engine 12, the main pump 34 is reduced in horsepower from the output horsepower of the engine 12 in accordance with fluctuations in the horsepower output from the sub-pump 38 that is distributed to the sub-pump 38.

[0034] Specifically, a third discharge hydraulic pressure P3 is supplied from the sub-pump 38 to the port 56d of the flow rate adjustment mechanism 42 via the flow path 54d. The third discharge hydraulic pressure P3 supplied to port 56d presses the swash plate 44 in a direction that decreases the inclination angle, that is, in a direction that decreases the discharge flow rate Q of the main pump 34. When the third discharge hydraulic pressure P3 increases or decreases, the inclination angle of the swash plate 44 decreases or increases against the biasing force of the biasing mechanism 48 by the third discharge hydraulic pressure P3, or against the hydraulic pressure of the third discharge hydraulic pressure P3, causing the discharge flow rate Q of the main pump 34 to decrease or increase, and the absorbed horsepower of the main pump 34 to decrease or increase.

[0035] In this embodiment, a target horsepower to be output from the main pump 34 is set according to fluctuations in the horsepower output from the sub-pump 38, and the absorption horsepower of the main pump 34 is adjusted to be less than the set target horsepower and closer to the target horsepower, as described above.

[0036] Specifically, the third hydraulic pressure sensor 72c detects the third discharge hydraulic pressure P3 of the sub-pump 38 and outputs it to the controller 82. In the controller 82, the hydraulic pressure acquisition unit 88 acquires the detected third discharge hydraulic pressure P3 input from the third hydraulic pressure sensor 72c. Based on the detected third discharge hydraulic pressure P3 acquired by the hydraulic pressure acquisition unit 88, the pressure reducing valve control unit 86 acquires the horsepower output from the sub-pump 38 and sets a target horsepower to be output from the main pump 34 according to the horsepower output from the compressor 14 distributed to the air conditioner compressor 14 and the horsepower output from the sub-pump 38 distributed to the sub-pump 38 from the total horsepower output from the engine 12. Then, the hydraulic pressure acquisition unit 88 sets a target discharge flow rate Q of the main pump 34 to achieve the target horsepower output from the main pump 34, based on the total hydraulic pressure P of the first and second discharge hydraulic pressures P1 and P2 of the main pump 34 detected by the hydraulic pressure acquisition unit 88. t The detected total hydraulic pressure P is equal to the target discharge flow rate Q of the main pump 34. t The control current A supplied to the pressure reducing valve 62 is controlled to achieve the following result.

[0037] In this embodiment, a hydraulic mechanism comprising a pilot pump 36, a pressure reducing valve 62, and a pilot port 56c is used to supply pilot hydraulic pressure P to the swash plate 44. c The pilot hydraulic pressure P is applied to the swash plate 44 by the pressure reducing valve 62. c The inclination angle of the swash plate 44 is adjusted by adjusting its size, but the inclination angle of the swash plate 44 may also be adjusted by applying force to the swash plate 44 using an electromagnetic mechanism such as a solenoid valve, and further adjusting the magnitude of the force applied to the swash plate 44.

[0038] The output control method of this embodiment will be described with reference to Figure 3. As shown in Figure 3, the output control method of this embodiment comprises the following steps.

[0039] Drive state detection step S1 In the drive status detection step S1, it is detected whether the air conditioner compressor 14 of the hydraulic excavator 10 is being driven. If it is detected that the compressor 14 is being driven, the process proceeds to the hydraulic pressure acquisition step S2. If it is detected that the compressor 14 is not being driven, no adjustment is made to the output from the main pump 34.

[0040] Hydraulic acquisition step S2 In the hydraulic pressure acquisition step S2, the first and second discharge hydraulic pressures P1 and P2 of the hydraulic fluid discharged from the main pump 34, and the third discharge hydraulic pressure P3 of the hydraulic fluid discharged from the sub-pump 38, which are detected by the first to third hydraulic pressure sensors 72a, 72b, and 72c, are acquired.

[0041] Output control step S3 The output control step S3 includes the following steps:

[0042] Horsepower acquisition step S3-1 In the horsepower acquisition step S3-1, the horsepower output from the sub-pump 38 is acquired based on the third discharge hydraulic pressure P3 acquired in the hydraulic pressure acquisition step S2.

[0043] Target horsepower setting step S3-2 In the target horsepower setting step S3-2, the target horsepower to be output from the main pump 34 is set from the total horsepower output from the engine 12, according to the horsepower output from the air conditioner compressor 14 and the horsepower output from the sub-pump 38.

[0044] Output adjustment step S3-3 In the output adjustment step S3-3, the output horsepower, i.e., the absorbed horsepower, from the main pump 34 is adjusted to be less than the target horsepower and closer to the target horsepower by adjusting the discharge flow rate Q corresponding to the total hydraulic pressure P of the hydraulic fluid discharged from the main pump 34, based on the total hydraulic pressure P of the first and second discharge hydraulic pressures P1 and P2 of the main pump 34 acquired in the hydraulic pressure acquisition step S2.

[0045] Each step of the output control method in this embodiment corresponds to the respective functional configurations of the hydraulic excavator 10 of this embodiment described above, and therefore a detailed explanation is omitted.

[0046] Referring to Figure 4, the hardware configuration of the controller 82 in this embodiment will be described. As shown in Figure 4, the controller 82 of this embodiment is configured as a computer including a processor 91, memory 92, storage 93, input device 95, output device 96, communication device 94, and a bus connecting them. Each function or step in the controller 82 is realized or executed by loading a predetermined program onto hardware such as the processor 91 and memory 92, which causes the processor to perform calculations, control communication by the communication device, and control the reading and writing of data in the memory 92 and storage 93. The output control program of this embodiment causes the computer of the controller 82 to realize the output control functions of this embodiment described above and to execute each step of the output control method.

[0047] As described above, in this embodiment, for the main pump 34 driven by an engine 12 that outputs a predetermined horsepower, a target horsepower that the main pump 34 should output is set from the output horsepower of the engine 12, the first and second discharge hydraulic pressures P1 and P2 of the main pump 34 are detected, and the flow rate Q corresponding to the total hydraulic pressure P of the hydraulic fluid discharged from the main pump 34 is adjusted based on the total hydraulic pressure P of the detected first and second discharge hydraulic pressures P1 and P2, thereby making the output from the main pump 34 less than the target horsepower but close to the target horsepower. As a result, it is possible to make the most effective use of the output horsepower from the engine 12 in the main pump 34.

[0048] Furthermore, for the sub-pump 38, which is driven by the engine 12 and discharges a constant flow rate of hydraulic fluid, the third discharge hydraulic pressure P3 of the sub-pump 38 is detected, and based on the horsepower output from the sub-pump 38 obtained based on the detected third discharge hydraulic pressure P3, a target horsepower that the main pump 34 should output is set. Therefore, regardless of fluctuations in the horsepower output from the sub-pump 38, the main pump 34 can effectively utilize the horsepower output from the engine 12.

[0049] The key disclosures of this application can be summarized as follows: The first disclosure is an output control device for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, comprising: a hydraulic pressure acquisition unit that acquires hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control unit that adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit.

[0050] In this disclosure, a hydraulic fluid discharge device driven by a power source outputting a predetermined horsepower detects the hydraulic pressure of the hydraulic fluid discharged from the device and adjusts the flow rate corresponding to the hydraulic pressure of the hydraulic fluid discharged from the device based on the detected hydraulic pressure. This adjusts the output from the hydraulic fluid discharge device, making it possible to effectively utilize the output horsepower from the power source in the hydraulic fluid discharge device.

[0051] The second disclosure is an output control device of the first disclosure, wherein the output control unit sets a target horsepower to be output from the hydraulic fluid discharge device from the output horsepower of the power source, and controls the output from the hydraulic fluid discharge device to approach the target horsepower.

[0052] In this disclosure, a target horsepower to be output from the hydraulic fluid discharge device is set from the output horsepower of the power source, and the output from the hydraulic fluid discharge device is controlled to approach the target horsepower. This makes it possible to make the most effective use of the output horsepower from the power source in the hydraulic fluid discharge device.

[0053] The third disclosure is an output control device as described in the second disclosure, wherein the output control unit moves the characteristic curve, which shows the correspondence between the hydraulic pressure of the hydraulic fluid and the flow rate of the hydraulic fluid in the hydraulic fluid discharge device, to intersect with the target horsepower curve that shows the target horsepower, at a predetermined hydraulic pressure value when the hydraulic pressure of the hydraulic fluid changes.

[0054] In this disclosure, when the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device changes, the flow rate discharged from the hydraulic fluid discharge device is adjusted by shifting the characteristic curve, which shows the correspondence between the hydraulic pressure and flow rate of the hydraulic fluid in the hydraulic fluid discharge device, so that it intersects with the target horsepower curve, which shows the target horsepower, at a predetermined hydraulic pressure.

[0055] The fourth disclosure is an output control device of the third disclosure, wherein the hydraulic fluid discharge device and the hydraulic pressure detection device are, respectively, a first hydraulic fluid discharge device and a first hydraulic pressure detection device, the hydraulic pressure acquisition unit acquires the hydraulic pressure detected by the first hydraulic pressure detection device as the first hydraulic pressure, and acquires the hydraulic pressure detected by a second hydraulic pressure detection device, which is driven by the power source and detects the hydraulic pressure of the hydraulic fluid discharged from a second hydraulic fluid discharge device that has a constant flow rate of discharged hydraulic fluid, as the second hydraulic pressure, and the output control unit sets a target horsepower to be output from the first hydraulic fluid discharge device based on the horsepower of the output from the second hydraulic fluid discharge device acquired based on the second hydraulic pressure acquired by the hydraulic pressure acquisition unit.

[0056] In this disclosure, a second hydraulic fluid discharge device, which is driven by a power source and discharges a constant flow rate of hydraulic fluid, detects a second hydraulic pressure, which is the hydraulic pressure of the hydraulic fluid discharged from the second hydraulic fluid discharge device. Based on the horsepower output from the second hydraulic fluid discharge device, which is obtained based on the detected second hydraulic pressure, a target horsepower to be output from the first hydraulic fluid discharge device is set. Therefore, regardless of fluctuations in the horsepower output from the second hydraulic fluid discharge device, it is possible to effectively utilize the output horsepower supplied from the power source in the first hydraulic fluid discharge device.

[0057] The fifth disclosure is an output control system comprising the hydraulic detection device, output control device, flow rate adjustment device, and output modification device as described in any of the first to fourth disclosures, wherein the flow rate adjustment device comprises a flow rate adjustment member and a biasing mechanism for adjusting the position of the flow rate adjustment member, the output modification device changes the position of the flow rate adjustment member by changing the magnitude of the force applied to the flow rate adjustment member, and changes the output from the hydraulic fluid discharge device by changing the flow rate of the hydraulic fluid discharge device, and the output control unit controls the output modification device based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit, thereby adjusting the magnitude of the force applied to the flow rate adjustment member by the output modification device and adjusting the position of the flow rate adjustment member. This disclosure has the same effect as the first disclosure.

[0058] The sixth disclosure is a work vehicle comprising the power source, the hydraulic fluid discharge device, and the output control system described in the fifth disclosure. This disclosure has the same effect as the first disclosure.

[0059] The seventh disclosure is an output control method for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, comprising: an oil pressure acquisition step of acquiring an oil pressure detected by an oil pressure detection device that detects the oil pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control step of adjusting the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the oil pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the oil pressure acquired in the oil pressure acquisition step. This disclosure has the same effect as the first disclosure.

[0060] The eighth disclosure is an output control program for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs at a predetermined horsepower, the output control program which enables a computer to implement: a hydraulic pressure acquisition function that acquires the hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device; and an output control function that adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the hydraulic pressure acquired by the hydraulic pressure acquisition function. This disclosure has the same effect as the first disclosure. [Explanation of Symbols]

[0061] 10... Hydraulic excavator (work vehicle) 12... Engine (power source) 14... Compressor 16... Hydraulic drive unit 18... Control valve 22a... First supply channel 22b...Second supply channel 22c...Third supply channel 30...Hydraulic fluid supply system 32...Pump unit 34...Main pump (hydraulic oil discharge device, first hydraulic oil discharge device) 36...Pilot pump 38...Sub-pump (second hydraulic fluid discharge device) 40…Output control system 42…Flow rate adjustment mechanism (flow rate adjustment device) 44...Swash plate (flow rate adjustment member) 48...Biasing mechanism 52a...First elastic member 52b...Second elastic member 54c...Pilot channel 54d...Channel 56c...Pilot port 56d...Port 62...Pressure reducing valve (output change device) 72a...First hydraulic sensor (hydraulic detection device, first hydraulic detection device) 72b...Second hydraulic sensor (hydraulic detection device, first hydraulic detection device) 72c...Third hydraulic sensor (second hydraulic detection device) 82...Controller (output control device) 84...Drive state detection unit 86... Pressure reducing valve control unit (output control unit) 88... Hydraulic pressure acquisition unit 91... Processor 92...Memory 93...Storage 94...Communication device 95...Input device 96...Output device

Claims

1. An output control device for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, A hydraulic pressure acquisition unit acquires the hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device, An output control unit adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid corresponding to the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit, An output control device equipped with the following features.

2. The output control unit sets a target horsepower to be output from the hydraulic fluid discharge device from the output horsepower of the power source, and controls the output from the hydraulic fluid discharge device to approach the target horsepower. The output control device according to claim 1.

3. The output control unit, when the hydraulic pressure of the hydraulic fluid changes, moves the characteristic curve, which shows the correspondence between the hydraulic pressure of the hydraulic fluid and the flow rate of the hydraulic fluid in the hydraulic fluid discharge device, to intersect the target horsepower curve that shows the target horsepower at a predetermined hydraulic pressure. The output control device according to claim 2.

4. The hydraulic fluid discharge device and the hydraulic pressure detection device are, respectively, a first hydraulic fluid discharge device and a first hydraulic pressure detection device. The hydraulic pressure acquisition unit acquires the hydraulic pressure detected by the first hydraulic pressure detection device as the first hydraulic pressure, and acquires the hydraulic pressure detected by the second hydraulic pressure detection device, which is driven by the power source and detects the hydraulic pressure of the hydraulic fluid discharged from the second hydraulic fluid discharge device, where the flow rate of the discharged hydraulic fluid is constant, as the second hydraulic pressure. The output control unit sets a target horsepower to be output from the first hydraulic fluid discharge device based on the horsepower of the output from the second hydraulic fluid discharge device, which is obtained based on the second hydraulic pressure obtained by the hydraulic pressure acquisition unit. The output control device according to claim 3.

5. The hydraulic detection device according to any one of claims 1 to 4, the output control device, the flow rate adjustment device, and the output modification device are provided, The flow rate adjustment device comprises a flow rate adjustment member and a biasing mechanism for adjusting the position of the flow rate adjustment member. The output changing device changes the position of the flow rate adjusting member by changing the magnitude of the force applied to the flow rate adjusting member, thereby changing the flow rate of the hydraulic fluid discharged from the hydraulic fluid discharge device, and thus changing the output from the hydraulic fluid discharge device. The output control unit controls the output modification device based on the hydraulic pressure acquired by the hydraulic pressure acquisition unit, thereby adjusting the magnitude of the force applied to the flow rate adjustment member by the output modification device and adjusting the position of the flow rate adjustment member. Output control system.

6. A work vehicle comprising the power source described in claim 5, the hydraulic fluid discharge device, and the output control system.

7. An output control method for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, A hydraulic pressure acquisition step involves acquiring the hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device, An output control step that adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid discharged from the hydraulic fluid discharge device, based on the hydraulic pressure acquired in the hydraulic pressure acquisition step, An output control method comprising the following:

8. An output control program for adjusting the output from a hydraulic fluid discharge device driven by a power source that outputs a predetermined horsepower, On the computer, A hydraulic pressure acquisition function that acquires the hydraulic pressure detected by a hydraulic pressure detection device that detects the hydraulic pressure of the hydraulic fluid discharged from the hydraulic fluid discharge device, Based on the hydraulic pressure acquired by the hydraulic pressure acquisition function, an output control function adjusts the output from the hydraulic fluid discharge device by adjusting the flow rate of the hydraulic fluid discharged from the hydraulic fluid discharge device that corresponds to the hydraulic pressure, An output control program that achieves this.

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