Hydraulic circuit system with abnormality diagnosis function and steering device provided with same

Abstract

A hydraulic circuit system with an abnormality diagnosis function is provided with: at least one positive displacement pump; the hydraulic circuit is connected with the pump; a downstream-side sensor that detects a state quantity of the hydraulic fluid flowing downstream of the hydraulic circuit; and an abnormality diagnosis device that determines an abnormality in the hydraulic circuit on the basis of a first state quantity of the hydraulic fluid discharged from the pump and a second state quantity of the hydraulic fluid detected by the downstream sensor.

Description

Technical Field

[0001] The present invention relates to a hydraulic circuit system with an abnormality diagnosis function for judging abnormality of a hydraulic circuit and a steering device equipped with the hydraulic circuit system. Background Art

[0002] Positive displacement pumps such as swash plate pumps are widely used in industrial machinery such as marine machinery and construction machinery. As an abnormality diagnosis device for detecting abnormality of a positive displacement pump, a fault diagnosis device such as that disclosed in Patent Document 1 is known.

[0003] Prior art literature: Patent Literature: Patent document 1: Japanese Patent No. 6340121. Summary of the invention

[0004] Problems to be solved by the invention: The fault diagnosis device of Patent Document 1 can diagnose a fault of a positive displacement pump based on the suction pressure of the working fluid, but does not assume that an abnormality of a hydraulic circuit connected to the pump can be determined.

[0005] Therefore, an object of the present invention is to provide a hydraulic circuit system with an abnormality diagnosis function capable of determining an abnormality in the hydraulic circuit, and a steering device including the hydraulic circuit system.

[0006] Means of solving the problem: The hydraulic circuit system of the present invention comprises: at least one positive displacement pump; a hydraulic circuit connected to the pump; a downstream side sensor which detects the state quantity of the working fluid flowing on the downstream side of the hydraulic circuit; and an abnormality diagnosis device which determines the abnormality of the hydraulic circuit based on a comparison result of a first state quantity of the working fluid discharged from the pump and a second state quantity of the working fluid detected by the downstream side sensor.

[0007] According to the present invention, a change in the state quantity of the working fluid flowing in the hydraulic circuit can be detected based on the first state quantity of the working fluid discharged from the pump and the second state quantity of the working fluid detected by the downstream sensor. Furthermore, an abnormality in the hydraulic circuit can be determined based on the change in the hydraulic pressure.

[0008] A steering device according to the present invention includes the aforementioned hydraulic circuit system with an abnormality diagnosis function.

[0009] According to the present invention, a steering device having the above-mentioned functions can be realized.

[0010] Effect of the invention: According to the present invention, it is possible to determine abnormality in the hydraulic circuit.

[0011] The above objects, other objects, features and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 1 is a circuit diagram showing a hydraulic circuit system with an abnormality diagnosis function according to a first embodiment of the present invention; Figure 2 It is shown in Figure 1 A graph showing the time variation of the pressure detected by each sensor in a hydraulic circuit system with an abnormality diagnosis function, (a) is the time variation of the pressure detected by each sensor when the pump is driven normally, and (b) is the time variation of the pressure detected by each sensor when the pump is stopped normally; Figure 3 It is shown in Figure 1 A graph showing the time variation of the pressure detected by each sensor in a hydraulic circuit system with an abnormality diagnosis function, (a) is the time variation of the pressure detected by each sensor when the second shut-off valve is stuck in a closed state, and (b) is the time variation of the pressure detected by each sensor when the working fluid leaks; Figure 4 is a circuit diagram showing a hydraulic circuit system with an abnormality diagnosis function according to a second embodiment of the present invention; Figure 5 It is shown in Figure 4 A graph showing the time variation of the pressure detected by each sensor when the hydraulic circuit is normal in a hydraulic circuit system with an abnormality diagnosis function; Figure 6 It is shown in Figure 4 A graph showing changes over time in the pressure detected by each sensor when a hydraulic circuit is abnormal in a hydraulic circuit system with an abnormality diagnosis function; Figure 7 is a circuit diagram showing a hydraulic circuit system with an abnormality diagnosis function according to a third embodiment of the present invention; Figure 8 is Figure 7 A graph showing the results of frequency analysis of waveform data of downstream pressure in a hydraulic circuit system with an abnormality diagnosis function, where (a) is the frequency analysis result when the hydraulic circuit is normal, and (b) is the frequency analysis result when the hydraulic circuit is abnormal; Fig. 9 is a circuit diagram showing a hydraulic circuit system with an abnormality diagnosis function according to a fourth embodiment of the present invention; Fig.10 is a circuit diagram showing a hydraulic circuit system with an abnormality diagnosis function according to a fifth embodiment of the present invention; Fig.11This is a circuit diagram showing a steering device including a hydraulic circuit system with an abnormality diagnosis function according to a sixth embodiment of the present invention. DETAILED DESCRIPTION

[0013] Hereinafter, the hydraulic circuit system with abnormality diagnosis function (hereinafter referred to as "hydraulic circuit system") 1, 1A to 1E and the steering device 2 equipped with the hydraulic circuit system according to the first to sixth embodiments of the present invention will be described with reference to the above-mentioned drawings. In addition, the directional concepts used in the following description are used only for the convenience of description, and the structural orientation of the invention is not limited to the direction. In addition, the hydraulic circuit system 1, 1A to 1E and the steering device 2 described below are only one embodiment of the present invention. Therefore, the present invention is not limited to the embodiment, and additions, deletions, and changes can be made within the scope of the main purpose of the invention.

[0014] <Hydraulic circuit system> Figure 1 The hydraulic circuit system 1 shown drives the hydraulic actuator 3 by supplying working fluid (for example, oil and water) to the hydraulic actuator 3. The hydraulic actuator 3 is, for example, a hydraulic cylinder and a hydraulic motor. In addition, the hydraulic circuit system 1 can diagnose abnormalities in the hydraulic circuit system 1. The hydraulic circuit system 1 includes a hydraulic pump 11, a hydraulic circuit 12, a downstream sensor 13, and a control device 14. In addition, the hydraulic circuit system 1 also includes an upstream sensor 15.

[0015] <Hydraulic pump> The hydraulic pump 11 discharges working fluid. The hydraulic pump 11 is a positive displacement hydraulic pump. That is, the working fluid discharged from the hydraulic pump 11 pulsates. The hydraulic pump 11 is, for example, a reciprocating pump (a swash plate pump, a slant axis pump, a piston pump, etc.), a gear pump, a trochoid pump, etc. In the present embodiment, the hydraulic pump 11 is a swash plate pump.

[0016] <Hydraulic circuit> The hydraulic circuit 12 is connected to the hydraulic pump 11 and the hydraulic actuator 3. The hydraulic circuit 12 supplies the hydraulic fluid discharged from the hydraulic pump 11 to the hydraulic actuator 3. Furthermore, the hydraulic circuit 12 controls the flow of the hydraulic fluid supplied from the hydraulic pump 11 to the actuator 3. The hydraulic circuit 12 includes a fluid passage 21, a plurality of shutoff valves 22 and 23, and a relief valve 24. In addition, the hydraulic circuit 12 may also include Figure 1 Other structures included in the hydraulic circuit 12 include, for example, valves such as a directional switching valve, a check valve, and a control valve, and a throttle.

[0017] The liquid passage 21 is connected to the hydraulic pump 11 and the hydraulic actuator 3. And the liquid passage 21 supplies the working fluid discharged from the hydraulic pump 11 to the hydraulic actuator 3. A plurality of cut-off valves 22 and 23 as an example of a hydraulic control device are respectively arranged in series in the liquid passage 21. In the present embodiment, two cut-off valves 22 and 23 are arranged in the liquid passage 21. In addition, in the liquid passage 21, the cut-off valve 22 located on the upstream side is the first cut-off valve 22, and the cut-off valve 23 located on the downstream side is the second cut-off valve 23. The two cut-off valves 22 and 23 are, for example, normally open cut-off valves. That is, the cut-off valves 22 and 23 close the liquid passage 21 according to the input control signal. In addition, the two cut-off valves 22 and 23 may also be normally closed cut-off valves. The relief valve 24 is connected to the liquid passage 21. In more detail, the relief valve 24 is connected to the downstream side of the two cut-off valves 22 and 23 in the liquid passage 21. The relief valve 24 discharges the working fluid in the fluid passage 21 to the tank 25 when the hydraulic pressure in the fluid passage 21 reaches a predetermined pressure or more.

[0018] <Upstream sensor> The upstream sensor 15 detects a first state quantity of the working fluid discharged from the hydraulic pump 11. The upstream sensor 15 is arranged on the upstream side of the hydraulic circuit 12. In more detail, the upstream sensor 15 is connected to the upstream side of the two shut-off valves 22 and 23 in the liquid passage 21. The upstream sensor 15 is a hydraulic sensor in the present embodiment, and detects the hydraulic pressure of the working fluid discharged from the hydraulic pump 11, that is, the discharge pressure. In addition, the upstream sensor 15 may also be a flow sensor. In this case, the upstream sensor 15 detects the flow rate as the first state quantity.

[0019] <Downstream sensor> The downstream side sensor 13 detects the second state quantity of the working fluid flowing on the downstream side of the hydraulic circuit 12. The downstream side sensor 13 is arranged on the downstream side of the hydraulic circuit 12. In more detail, the downstream side sensor 13 is connected to the downstream side of the two shut-off valves 22 and 23 in the liquid passage 21. Moreover, the downstream side sensor 13 is connected to the downstream side of the overflow valve 24 in the liquid passage 21. The downstream side sensor 13 is a hydraulic sensor in the present embodiment, and detects the hydraulic pressure on the downstream side of the hydraulic circuit 12, that is, the downstream pressure. In addition, the downstream side sensor 13 can also be a flow sensor. In this case, the downstream side sensor 13 detects the flow rate as the second state quantity.

[0020] <Control device> The control device 14 outputs a control signal to the shutoff valves 22 and 23. The control device 14 controls the operation of the shutoff valves 22 and 23 by outputting a control signal to the shutoff valves 22 and 23. In more detail, the control device 14 operates the first shutoff valve 22 by outputting a first control signal. In addition, the control device 14 operates the second shutoff valve 23 by outputting a second control signal. Furthermore, the control device 14 closes the liquid passage 21 by operating any one of the shutoff valves 22 and 23.

[0021] In addition, the control device 14 as an example of an abnormality diagnosis device determines the abnormality of the hydraulic circuit 12 based on the discharge pressure of the hydraulic pump 11 and the downstream pressure detected by the downstream side sensor 13. In more detail, the control device 14 obtains the discharge pressure and the downstream pressure from each sensor 13, 15. The control device 14 determines the abnormality of the hydraulic circuit 12 based on the comparison result of the obtained downstream pressure and the discharge pressure. In the present embodiment, the control device 14 determines the abnormality of the hydraulic circuit 12 based on the comparison result of the waveform data of the discharge pressure and the waveform data of the downstream pressure.

[0022] <Operation of the hydraulic circuit system> In the hydraulic circuit system 1, when the control device 14 does not output a control signal to the cut valves 22 and 23 (i.e., referred to as a "non-energized state"), the fluid passage 21 is open. Therefore, the hydraulic fluid discharged from the hydraulic pump 11 is supplied to the hydraulic actuator 3. As a result, the hydraulic actuator 3 is operated.

[0023] Next, the control device 14 outputs at least one of the first and second control signals based on a program or an instruction from an operating device (hereinafter referred to as "program, etc.") not shown. The operating device is a device that outputs a command signal (electrical signal, hydraulic signal, etc.) by being operated, such as a lever, a switch, and a touch panel. The first shutoff valve 22 closes the liquid passage 21 when the first control signal is output from the control device 14. In addition, the second shutoff valve 23 closes the liquid passage 21 when the second control signal is output from the control device 14. When at least one of the shutoff valves 22 and 23 closes the liquid passage 21, the operation of the hydraulic actuator 3 stops.

[0024] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1, the control device 14 diagnoses an abnormality of the hydraulic circuit 12 based on the discharge pressure and the downstream pressure. In more detail, the control device 14 diagnoses an abnormality of the hydraulic circuit 12 based on the comparison result of the discharge pressure and the downstream pressure. In the present embodiment, the control device 14 diagnoses an abnormality of the hydraulic circuit 12 based on the control signal, the waveform data of the discharge pressure, and the waveform data of the downstream pressure. The abnormality diagnosis method is described in further detail below.

[0025] In the hydraulic circuit system 1, in each of the de-energized state and the stopped state in which the hydraulic pump 11 is stopped, the control device 14 obtains the discharge pressure from the upstream sensor 15 and obtains the downstream pressure from the downstream sensor 13. The control device 14 generates the change of the discharge pressure over time, that is, the waveform data of the discharge pressure, based on the obtained discharge pressure. In addition, the control device 14 generates the change of the downstream pressure over time, that is, the waveform data of the downstream pressure, based on the obtained downstream pressure. And, the control device 14 compares the waveform data of the discharge pressure generated in the de-energized state and the stopped state with the waveform data of the discharge pressure. Based on the comparison result, the control device 14 diagnoses the abnormality of the hydraulic circuit 12.

[0026] In the non-powered state, for example, the control device 14 generates Figure 2 (a) The waveform data of the discharge pressure and the waveform data of the downstream pressure are generated in the pulsation state (refer to Figure 2 (a) "discharge pressure waveform data" and "downstream pressure waveform data"). Based on the comparison result of the two generated waveform data, the control device 14 determines that the two waveform data are the same. Therefore, the control device 14 determines that both the shutoff valves 22 and 23 are operating normally.

[0027] Likewise, in the stopped state, the control device 14 generates, for example, Figure 2 (b) The waveform data of the discharge pressure and the waveform data of the downstream pressure are generated at a constant pressure (for example, tank pressure) (see Figure 2 (b) "discharge pressure waveform data" and "downstream pressure waveform data"). Based on the comparison result of the two generated waveform data, the control device 14 determines that the two waveform data are the same. Therefore, the control device 14 determines that both the shutoff valves 22 and 23 are operating normally.

[0028] On the other hand, in the hydraulic circuit system 1, in the non-powered state, there is a situation where the control device 14 generates Figure 3 (a) The waveform data of the discharge pressure and the waveform data of the downstream pressure are as follows. That is, the waveform data of the discharge pressure generated is pulsating (refer to Figure 3 (a) "discharge pressure waveform data"). On the other hand, the generated downstream pressure waveform data is different from the downstream pressure waveform data in normal state (refer to Figure 3 (a) "Downstream pressure waveform data" (dotted line) is different, and becomes a constant pressure (tank pressure) (refer to Figure 3(a) "waveform data of downstream pressure" solid line). In this way, when the two waveform data are different and the downstream pressure is constant in a state where the control signal is not output, the control device 14 determines that the hydraulic circuit 12 is abnormal based on the control signal and the two waveform data. In more detail, the control device 14 determines that any one of the shutoff valves 22 and 23 is stuck in the closed state of closing the liquid passage 21. In this way, the control device 14 can diagnose abnormalities related to the response of the shutoff valves 22 and 23 to the control signal.

[0029] Furthermore, in the non-powered state, the control device 14 generates, for example, Figure 3 (b) The case of the waveform data of the discharge pressure and the waveform data of the downstream pressure. That is, with respect to the waveform data of the discharge pressure generated (refer to Figure 3 (b) "Discharge pressure waveform data"), the downstream pressure waveform data is greatly attenuated (refer to Figure 3 (b) The solid line and the two-dot chain line of the "waveform data of the downstream pressure" are shown). Then, the control device 14 diagnoses that the hydraulic circuit 12 is abnormal. More specifically, the control device 14 diagnoses that a liquid leakage occurs in the liquid passage 21.

[0030] In the hydraulic circuit system 1 of the first embodiment, it is possible to detect changes in the hydraulic pressure of the working fluid flowing in the hydraulic circuit 12 based on the discharge pressure of the hydraulic pump 11 and the downstream pressure detected by the downstream sensor 13. Furthermore, it is possible to determine an abnormality in the hydraulic circuit 12 based on the change in the hydraulic pressure. Thus, it is possible to easily determine an abnormality in the hydraulic circuit 12.

[0031] In the hydraulic circuit system 1 of the first embodiment, the hydraulic circuit 12 includes the shutoff valves 22 and 23. The control device 14 can determine the abnormality of the shutoff valves 22 and 23 included in the hydraulic circuit 12 by finding the change in the pressure of the working fluid flowing through the shutoff valves 22 and 23 based on the discharge pressure and the downstream pressure.

[0032] In the hydraulic circuit system 1 of the first embodiment, the control device 14 determines abnormality of the shutoff valves 22, 23 based on the control signal, the discharge pressure, and the downstream pressure. Therefore, the control device 14 can determine abnormality related to the response of the shutoff valves 22, 23 to the control signal.

[0033] Furthermore, in the hydraulic circuit system 1 of the first embodiment, the control device 14 determines an abnormality of the hydraulic circuit 12 based on the waveform data of the discharge pressure and the waveform data of the downstream pressure. In the case of diagnosis based on the waveform data of the discharge pressure and the waveform data of the downstream pressure, it is easier to find a qualitative change of the downstream pressure relative to the discharge pressure than in the case of diagnosis based only on the discharge pressure and the downstream pressure. Therefore, the control device 14 can easily perform abnormality determination of the hydraulic circuit 12.

[0034] In addition, in the hydraulic circuit system 1 of the first embodiment, the discharge pressure and the downstream pressure are both detected by the sensors 15 and 13. And the control device 14 determines the abnormality of the hydraulic circuit 12 based on the hydraulic pressure on the upstream side of the hydraulic circuit 12, that is, the actual hydraulic pressure of the discharge pressure and the downstream pressure. Therefore, the control device 14 can improve the accuracy of determining the abnormality of the hydraulic circuit 12.

[0035] <Second embodiment> The hydraulic circuit system 1A of the second embodiment is similar in structure to the hydraulic circuit system 1 of the first embodiment. Therefore, for the structure of the hydraulic circuit system 1A of the second embodiment, mainly the points different from the hydraulic circuit system 1A of the first embodiment will be described, and the same reference numerals will be given to the same structures and the description will be omitted. In addition, the same is true for the hydraulic circuit systems 1B to 1E of the third to sixth embodiments, and the same reference numerals will be given to the same structures and the description will be omitted.

[0036] The hydraulic circuit system 1A of the second embodiment is as follows Figure 4 As shown, the hydraulic circuit system 1A includes a plurality of hydraulic pumps 11, 11A, a hydraulic circuit 12A, a downstream sensor 13A, and a control device 14A. In addition, the hydraulic circuit system 1A includes a plurality of upstream sensors 15, 15A.

[0037] <Hydraulic pump> The plurality of hydraulic pumps 11 and 11A all discharge working fluid. In the present embodiment, the first hydraulic pump 11 and the second hydraulic pump 11A are provided in the hydraulic circuit system 1A. The second hydraulic pump 11A is a positive displacement hydraulic pump like the first hydraulic pump 11. That is, the working fluid discharged by the second hydraulic pump 11A also pulsates. The second hydraulic pump 11A is, for example, a reciprocating pump (a swash plate pump, a slant axis pump, a piston pump, etc.), a gear pump, a trochoid pump, etc. In the present embodiment, the second hydraulic pump 11A is also a swash plate pump.

[0038] <Hydraulic circuit> The hydraulic circuit 12A is connected to both the hydraulic pumps 11 and 11A. In addition, the hydraulic circuit 12A is also connected to the hydraulic actuator 3. The hydraulic circuit 12A merges the working fluids flowing out of the two hydraulic pumps 11 and 11A. And the hydraulic circuit 12A supplies the merged working fluid to the hydraulic actuator 3. In addition, the hydraulic circuit 12A controls the flow of the working fluid supplied from the hydraulic pumps 11 and 11A to the hydraulic actuator 3. The hydraulic circuit 12A has a plurality of circuit systems 31 and 31A, a merging passage 33, and a relief valve 24.

[0039] The plurality of circuit systems 31, 31A are respectively connected to the hydraulic pumps 11, 11A. In the present embodiment, the hydraulic circuit 12A has two circuit systems 31, 31A, which are the same number as the hydraulic pumps 11, 11A. Furthermore, the first circuit system 31 as one of the circuit systems 31 is connected to the first hydraulic pump 11, and the second circuit system 31A as the other circuit system 31A is connected to the second hydraulic pump 11A. Working fluid discharged from the connected hydraulic pumps 11, 11A flows in the circuit systems 31, 31A. Furthermore, the circuit systems 31, 31A control the flow of the working fluid flowing in the circuit systems 31, 31A. The circuit systems 31, 31A have the same structure in the present embodiment.

[0040] The first circuit system 31 includes, for example, a first liquid passage 21 and a first directional control valve 34. In addition, the first circuit system 31 may also include Figure 4 Other structures included in the first circuit system 31 include, for example, a shutoff valve, a check valve, a throttle, and a control valve.

[0041] The first liquid passage 21 is connected to the first hydraulic pump 11. The working fluid is discharged from the first hydraulic pump 11 to the first liquid passage 21. The first directional control valve 34, which is an example of a hydraulic control device, is disposed in the first liquid passage 21. The first directional control valve 34 controls the flow of the first liquid passage 21 according to an input first control signal. In more detail, the first directional control valve 34 closes the first liquid passage 21 according to the input first control signal. As a result, the flow to the downstream side in the first liquid passage 21 is stopped.

[0042] The second circuit system 31A includes a second liquid passage 21A and a second directional control valve 34A. In addition, the second circuit system 31A may also include the same as the first circuit system 31. Figure 4 Structures other than those shown.

[0043] The second liquid passage 21A is connected to the second hydraulic pump 11A. And the working fluid is discharged from the second hydraulic pump 11A to the second liquid passage 21A. The second directional control valve 34A, which is an example of a hydraulic control device, is disposed in the second liquid passage 21A. The second directional control valve 34A also closes the second liquid passage 21A according to the input second control signal. As a result, the flow to the downstream side in the second liquid passage 21A stops.

[0044] The confluence passage 33 is connected to the two circuit systems 31 and 31A. And, in the confluence passage 33, the working fluids flowing in the two circuit systems 31 and 31A merge. To explain in more detail, the confluence passage 33 is connected to the first liquid passage 21 of the first circuit system 31 and the second liquid passage 21A of the second circuit system 31A. And, in the confluence passage 33, the working fluids of the hydraulic pumps 11 and 11A flowing through the two liquid passages 21 and 21A merge. In addition, the hydraulic actuator 3 is connected to the confluence passage 33. Therefore, after the working fluids of the two hydraulic pumps 11 and 11A merge in the confluence passage 33, it is possible to flow to the hydraulic actuator 3. In addition, in the confluence passage 33, the relief valve 24 is connected to the downstream side of the confluence point 33a where the working fluids of the two hydraulic pumps 11 and 11A merge.

[0045] <Upstream sensor> A plurality of upstream side sensors 15, 15A detect the first state quantity of the working fluid discharged from the hydraulic pumps 11, 11A, respectively. In the present embodiment, the hydraulic circuit system 1A is provided with two upstream side sensors 15, 15A, the same number as the hydraulic pumps 11, 11A. The first upstream side sensor 15, which is one of the upstream side sensors 15, is connected to the upstream side of the first directional control valve 34 in the first liquid passage 21. In addition, the second upstream side sensor 15A, which is the other upstream side sensor 15A, is connected to the upstream side of the second directional control valve 34A in the second liquid passage 21A. To explain in more detail, the upstream side sensors 15, 15A are located at the most upstream side in each liquid passage 21, 21A, respectively. In addition, the upstream side sensors 15, 15A are hydraulic sensors in the present embodiment, and detect the discharge pressure of the hydraulic pumps 11, 11A, respectively. In addition, the upstream side sensors 15, 15A may also be flow sensors.

[0046] <Downstream sensor> The downstream sensor 13A detects a second state quantity of the working fluid flowing on the downstream side of the hydraulic circuit 12A. The downstream sensor 13A is connected to the downstream side of the merging passage 33 from the merging point 33a. The downstream sensor 13A is a pressure sensor in the present embodiment, and detects the hydraulic pressure of the working fluid flowing on the downstream side of the merging passage 33, that is, the downstream pressure. Alternatively, the downstream sensor 13A may be a flow sensor.

[0047] <Control device> The control device 14A outputs a control signal to the directional control valves 34 and 34A. The control device 14 controls the operation of the directional control valves 34 and 34A by outputting a control signal to the directional control valves 34 and 34A. In more detail, the control device 14 outputs a first control signal and a second control signal according to a program or the like. As a result, the first directional control valve 34 and the second directional control valve 34A operate.

[0048] In addition, the control device 14A, which is an example of an abnormality diagnosis device, determines the abnormality of the hydraulic circuit 12A based on the discharge pressure of the two hydraulic pumps 11 and 11A and the downstream pressure detected by the downstream sensor 13A. In more detail, the control device 14A obtains the discharge pressure from the two upstream sensors 15 and 15A, and obtains the downstream pressure from the downstream sensor 13. And the control device 14A determines the abnormality of the hydraulic circuit 12A based on the comparison result of the two obtained discharge pressures and the downstream pressure. In this embodiment, the control device 14A determines the abnormality of the hydraulic circuit 12A (in more detail, the abnormality of the circuit system 31 and 31A) based on the waveform data of the downstream pressure and the waveform data of the two discharge pressures.

[0049] <Operation of the hydraulic circuit system> In the hydraulic circuit system 1A, the control device 14A outputs a first control signal according to a program, etc. As a result, the first directional control valve 34 operates. Then, the working fluid is supplied from the first hydraulic pump 11 to the hydraulic actuator 3 via the first fluid passage 21 and the merging passage 33. As a result, the hydraulic actuator 3 expands.

[0050] In addition, the control device 14 outputs the second control signal together with the first control signal according to a program or the like. As a result, the second directional control valve 34A is also operated. Then, the working fluids of the two hydraulic pumps 11 and 11A merge in the merging passage 33 and are then supplied to the hydraulic actuator 3. Therefore, more working fluid can be supplied to the hydraulic actuator 3, so that the hydraulic actuator 3 can be extended more quickly.

[0051] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1A, the control device 14A determines the abnormality of the hydraulic circuit 12A based on the discharge pressure and the downstream pressure. In more detail, in the hydraulic circuit system 1A, the control device 14A determines the abnormality of the hydraulic circuit 12A based on the comparison result of the two discharge pressures and the downstream pressure. In the present embodiment, the control device 14 determines the abnormality of the hydraulic circuit 12A based on the control signal, the waveform data of the two discharge pressures, and the waveform data of the downstream pressure. The abnormality diagnosis method is described in further detail below.

[0052] In the hydraulic circuit system 1A, the control device 14A outputs the first and second control signals. At this time, the control device 14A obtains the discharge pressure from the two upstream sensors 15 and 15A, respectively, and obtains the downstream pressure from the downstream sensor 13. In addition, the control device 14A generates waveform data of the discharge pressure based on the two obtained discharge pressures, and generates waveform data of the downstream pressure based on the obtained downstream pressure. The control device 14A compares the generated waveform data of the discharge pressure with the waveform data of the discharge pressure. The control device 14A diagnoses the abnormality of the hydraulic circuit 12 based on the comparison result.

[0053] For example, the waveform data of two discharge pressures are as follows Figure 5 The pulsation is shown. Figure 5 In the embodiment, the discharge pressure detected by the first upstream sensor 15 is the first waveform data, and the discharge pressure detected by the second upstream sensor 15A is the second waveform data. In the present embodiment, the two hydraulic pumps 11 and 11A have the same structure, so the discharge pressure varies in basically the same cycle. However, even if the two hydraulic pumps 11 and 11A have the same structure, there are slight differences in the waveform data due to slight individual differences in the structure, etc. That is, the waveform data of the two discharge pressures have characteristic values ​​(see Figure 5 The first waveform data is within the double-dashed circle 11a, and the second waveform data is within the double-dashed circle 11b). In addition, in the waveform data of the downstream pressure detected by the downstream sensor 13A, by detecting the hydraulic pressure after the confluence, two characteristic values ​​of the waveform data of the discharge pressure appear (refer to Figure 5 Therefore, the control device 14A can diagnose the abnormality of the hydraulic circuit 12A based on the comparison result of the first waveform data and the second waveform data with the downstream pressure waveform data. That is, it compares whether the two characteristic values ​​of the first waveform data and the second waveform data appear in the downstream pressure waveform data.

[0054] like Figure 5 As shown in FIG. 1 , when two characteristic values ​​appear in the waveform data of the downstream pressure, the working fluids of the two hydraulic pumps 11 and 11A merge in the merging passage 33 and are supplied to the hydraulic actuator 3. Therefore, the control device 14 determines that the hydraulic circuit 12A is normal based on the presence or absence of the output of the two control signals, the first waveform data, the second waveform data, and the downstream pressure waveform data. On the other hand, if Figure 6 As shown, although two control signals are output, only one characteristic value (for example, the characteristic value of the first waveform data) appears in the waveform data of the downstream pressure (refer to Figure 6From the circle 11a in the waveform data of the downstream pressure, it can be seen that the working fluid from the second hydraulic pump 11A is not introduced into the merging passage 33. Therefore, the control device 14 determines that the hydraulic circuit 12A is abnormal, more specifically, the second circuit system 31A is abnormal, based on the presence or absence of the output of the two control signals, the first waveform data and the second waveform data, and the downstream pressure waveform data.

[0055] In the hydraulic circuit system 1A of the second embodiment, it is possible to confirm whether the working fluid of each hydraulic pump 11, 11A is supplied to the downstream side of the hydraulic circuit 12A (the hydraulic actuator 3 in this embodiment) based on the discharge pressure of each of the two hydraulic pumps 11, 11A and the downstream pressure detected by the downstream side sensor 13A. Thus, the control device 14 can determine in which hydraulic circuit 12A the working fluid of the hydraulic pump 11, 11A has not merged.

[0056] In addition, in the hydraulic circuit system 1A of the second embodiment, it is possible to confirm whether the working fluid discharged from the hydraulic pumps 11 and 11A is supplied to the downstream side of the hydraulic circuit 12A (the hydraulic actuator 3 in this embodiment) via each circuit system 31 and 31A based on the discharge pressure and downstream pressure of the plurality of hydraulic pumps 11 and 11A. Thus, it is possible to determine an abnormality in the circuit system 31 and 31A.

[0057] Furthermore, in the hydraulic circuit system 1A of the second embodiment, the waveform data related to the discharge pressure of the plurality of hydraulic pumps 11 and 11A is referred to for abnormality diagnosis of each circuit system 31 and 31A. In the case of diagnosis based on the waveform data of the discharge pressure and the waveform data of the downstream pressure, it is easier to find the qualitative change of the downstream pressure relative to the discharge pressure than in the case of diagnosis based only on the discharge pressure and the downstream pressure. Therefore, the control device 14 can easily determine the abnormality of the hydraulic circuit 12. That is, it is possible to easily diagnose the abnormality of each circuit system 31 and 31A.

[0058] Otherwise, the hydraulic circuit system 1A achieves the same operational effects as those of the hydraulic circuit system 1 of the first embodiment.

[0059] <Third embodiment> The hydraulic circuit system 1B of the third embodiment is as follows Figure 7 As shown in FIG. 1 , a plurality of hydraulic pumps 35 and 35B, a hydraulic circuit 12A, a downstream sensor 13A, and a control device 14B are provided. In the present embodiment, the hydraulic circuit system 1B includes two hydraulic pumps 35 and 35B.

[0060] The first hydraulic pump 35 and the second hydraulic pump 35B both discharge working fluid. The first hydraulic pump 35 and the second hydraulic pump 35B are both positive displacement and fixed capacity hydraulic pumps. In the present embodiment, the hydraulic pumps 35 and 35B are fixed capacity swash plate pumps. In addition, the pulsation in the discharge pressure of the hydraulic pumps 35 and 35B is different from each other. For example, in the hydraulic pumps 35 and 35B, since the number of pistons constituting each hydraulic pump is different, the respective pulsation periods are different. In addition, in the hydraulic pumps 35 and 35B, the rotational phases of the pistons are different, and thus the rotational phases of the respective pulsations are different.

[0061] The control device 14B controls the operation of the directional control valves 34 and 34A by outputting control signals similarly to the control device 14A. In addition, the control device 14B, which is an example of an abnormality diagnosis device, determines an abnormality of the hydraulic circuit 12A (more specifically, an abnormality of the circuit system 31 and 31A) based on the discharge pressure of the two hydraulic pumps 35 and 35B and the downstream pressure detected by the downstream side sensor 13A.

[0062] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1B, the control device 14B diagnoses abnormalities in the hydraulic circuit 12A based on the discharge pressure and the downstream pressure. In more detail, the control device 14B diagnoses abnormalities in the circuit systems 31 and 31A based on the comparison results of the respective pulsation cycles in the waveform data of the two discharge pressures and the pulsation cycles included in the waveform data of the downstream pressure. The abnormality diagnosis method is described in further detail below.

[0063] In the hydraulic circuit system 1B, the control device 14B opens the two fluid passages 21 and 21A by operating the two directional control valves 34 and 34A. Furthermore, the control device 14B obtains the downstream pressure from the downstream side sensor 13. Furthermore, the control device 14B generates waveform data of the downstream pressure based on the obtained downstream pressure. In addition, the control device 14B performs frequency analysis (e.g., FFT analysis) on the waveform data of the downstream pressure. Furthermore, the control device 14B obtains the intensity of each frequency related to the pulsation included in the waveform data of the downstream pressure. Furthermore, the control device 14 stores the pulsation cycles of the two discharge pressures in advance. In the waveform data of the downstream pressure, the working fluids of the two hydraulic pumps 11 and 11A merge, and thus the pulsation of the two working fluids appears in an overlapping state. Therefore, in the analysis result (i.e., spectrum) when the waveform data of the downstream pressure is frequency analyzed, the energy intensity of the pulsation cycles of the two discharge pressures increases. The control device 14 can diagnose the abnormality of the hydraulic circuit 12 based on the spectrum when the waveform data of the downstream pressure is frequency analyzed and the pre-stored pulsation cycle.

[0064] For example, when the two circuit systems 31 and 31A are normal, in the spectrum of the waveform data of the downstream pressure, as shown in FIG. Figure 8 As shown in (a), the energy intensity increases at two frequencies f1 and f2. On the other hand, when the second circuit system 31A is abnormal, in the spectrum of the waveform data of the downstream pressure, as shown in Figure 8 As shown in (b), the energy intensity of the frequency f2 is smaller than that in the normal state. In this case, the control device 14B determines that the hydraulic circuit 12A is abnormal, and more specifically, the second circuit system 31A is abnormal.

[0065] In the hydraulic circuit system 1B thus configured, the plurality of hydraulic pumps 35, 35B discharge working fluid that pulsates at different cycles. In this case, an abnormality in the hydraulic circuit 12A, more specifically, an abnormality in the circuit systems 31, 31A, can be diagnosed based on the pulsation cycle of the discharge pressure and the pulsation cycle of the downstream pressure.

[0066] Otherwise, the hydraulic circuit system 1B achieves the same operational effects as those of the hydraulic circuit system 1A of the second embodiment.

[0067] <Fourth embodiment> The hydraulic circuit system 1C of the fourth embodiment is as follows Fig. 9 As shown, the hydraulic circuit system 1C includes a plurality of hydraulic pumps 11, 11A, a hydraulic circuit 12A, a signal generator 26, a downstream sensor 13A, a control device 14C, and upstream sensors 15, 15A. In addition, the hydraulic circuit system 1C includes two hydraulic pumps 11, 11A in this embodiment. In addition, the hydraulic circuit system 1C also includes upstream sensors 15, 15A.

[0068] The signal generator 26 is, for example, provided at the second hydraulic pump 11A. In addition, the signal generator 26 may also be provided at both of the two pumps 11 and 11A. The signal generator 26 adds an additional signal to the working fluid by changing the first state quantity of the working fluid discharged from the second hydraulic pump 11A, that is, the discharge pressure of the second hydraulic pump 11A. The signal generator 26 is, for example, an electromagnetic proportional control valve. The signal generator 26 is connected to the second liquid passage 21A of the hydraulic circuit 12A. In addition, the signal generator 26 may also be a cut-off valve. When the signal generator 26 is a cut-off valve, it is interposed in the second liquid passage 21A. The signal generator 26 connects the second liquid passage 21A to the tank 25 according to the input working signal. Thus, since the discharge pressure of the second hydraulic pump 11A changes, it is possible to add an additional signal to the working fluid.

[0069] The control device 14C has the same function as the control device 14A. In addition, the control device 14C also has the following function. That is, the control device 14C outputs a working signal. Thus, the control device 14C can add an additional signal to the working fluid flowing in the second fluid passage 21A. For example, the control device 14C can output a working signal at a predetermined period to cause the pulsating working fluid having a frequency component different from the pulsation of the working fluid flowing in the first fluid passage 21 to flow to the second fluid passage 21A. In this way, the control device 14C adds an additional signal to the working fluid discharged from the second hydraulic pump 11A.

[0070] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1C, the control device 14C diagnoses abnormalities in the hydraulic circuit 12A based on the discharge pressure and the downstream pressure. In more detail, the control device 14C diagnoses abnormalities in the circuit systems 31 and 31A using the same method as the control device 14B. The abnormality diagnosis method is described in further detail below.

[0071] In the hydraulic circuit system 1C, the control device 14C opens the two liquid passages 21 and 21A by operating the two directional control valves 34 and 34A. In addition, the control device 14C operates the signal generator 26 by outputting a working signal. As a result, the working fluid flowing in the second liquid passage 21A is added with an additional signal. Thereafter, the control device 14C generates waveform data of two discharge pressures based on the two discharge pressures obtained from the upstream side sensors 15 and 15A. In addition, the control device 14C generates waveform data of the downstream pressure based on the downstream pressure obtained from the downstream side sensor 13. In addition, the control device 14C performs frequency analysis (e.g., FFT analysis) on the waveform data of the two discharge pressures and the waveform data of the downstream pressure (i.e., three waveform data). In addition, the control device 14 compares the frequency spectrum of the waveform data of the two discharge pressures with the frequency spectrum of the waveform data of the downstream pressure.

[0072] Since the waveform data of the two discharge pressures have frequency components different from each other, the control device 14 determines whether the aforementioned different frequency components are included in the waveform data of the downstream pressure. When the aforementioned different frequency components are included in the waveform data of the downstream pressure, the control device 14C determines that the working fluid of each hydraulic pump 11, 11A is supplied to the hydraulic actuator 3 via each circuit system 31, 31A. Therefore, the control device 14C determines that the hydraulic circuit 12A is normal. On the other hand, when the aforementioned different frequency components are included in the waveform data of the downstream pressure, the control device 14C determines that the working fluid of the frequency components not included is not supplied to the hydraulic actuator 3. Therefore, the control device 14C determines that the circuit systems 31, 31A through which the working fluid of the frequency components not included flows are abnormal. In this way, the control device 14C can diagnose the abnormality of the hydraulic circuit 12A by comparing the analysis results of the frequency analysis.

[0073] In the hydraulic circuit system 1C of the fourth embodiment, the additional signal is added to the working fluid by the signal generator 26. Therefore, by detecting the additional signal, it is possible to confirm whether the working fluid discharged from each hydraulic pump 11, 11A is supplied to the downstream side of the hydraulic circuit 12A (the hydraulic actuator 3 in this embodiment) via each circuit system 31, 31A.

[0074] Otherwise, the hydraulic circuit system 1C achieves the same operational effects as those of the hydraulic circuit system 1B of the third embodiment.

[0075] <Fifth Embodiment> The hydraulic circuit system 1D of the fifth embodiment is as follows Fig.10 As shown, the hydraulic pump 41, the hydraulic circuit 12D, a plurality of sensors 42 to 45, and the control device 14D are provided. The hydraulic pump 41 is a positive displacement hydraulic pump, and can discharge working fluid from any one of the two ports 41a and 41b. In the present embodiment, the hydraulic pump 41 is a double-rotation type swash plate pump. For example, the hydraulic pump 41 is connected to the motor 46. When the hydraulic pump 41 rotates in the forward direction by the motor 46, the working fluid is discharged from the port 41a on one side, and when it rotates in the reverse direction, the working fluid is discharged from the port 41b on the other side.

[0076] <Hydraulic circuit> The hydraulic circuit 12D is connected to the hydraulic pump 41. The hydraulic circuit 12D includes a hydraulic actuator 3D. In the hydraulic circuit 12D, the working fluid discharged from the hydraulic pump 41 is supplied to the hydraulic actuator 3, thereby the hydraulic actuator 3D operates. In the present embodiment, the hydraulic actuator 3D is a double-rotation type hydraulic motor. However, the hydraulic actuator 3D may also be a hydraulic cylinder. In addition, the hydraulic circuit 12D has two pump passages 47L, 47R, two opening and closing valves 48L, 48R, and a supply and discharge mechanism 49.

[0077] The pump passages 47L and 47R are connected to the ports 41a and 41b of the hydraulic pump 41. The two pump passages 47L and 47R are connected to the ports 41a and 41b of the hydraulic actuator 3D. In addition, throttles 47La and 47Ra are respectively interposed in the two pump passages 47L and 47R.

[0078] The on-off valves 48L and 48R are respectively interposed in the pump passages 47L and 47R. To explain in more detail, the on-off valves 48L and 48R are respectively interposed in the pump passages 47L and 47R on the hydraulic actuator 3D side relative to the throttles 47La and 47Ra. The on-off valves 48L and 48R open and close the pump passages 47L and 47R according to the input control signals.

[0079] Supply and discharge mechanism 49 is connected to pump passages 47L and 47R, respectively. Supply and discharge mechanism 49 supplies insufficient hydraulic fluid to pump passages 47L and 47R, respectively. Supply and discharge mechanism 49 also discharges hydraulic fluid to tank 25 when hydraulic pressure in each of pump passages 47L and 47R exceeds a predetermined pressure.

[0080] <Sensor> A plurality of sensors 42 to 45 detect the hydraulic pressure of the working fluid flowing in the pump passages 47L and 47R, respectively. In the present embodiment, four sensors 42 to 45 are provided in the hydraulic circuit system 1D. The sensors 42 to 45 are respectively connected to the pump passages 47L and 47R, respectively. In more detail, two sensors 42 and 43 are connected to the first pump passage 47L. The two sensors 42 and 43 are arranged on both sides of the throttle 47La in the first pump passage 47L. Two sensors 44 and 45 are connected to the second pump passage 47R. The two sensors 44 and 45 are arranged on both sides of the throttle 47Ra in the second pump passage 47R. Furthermore, any one of the plurality of sensors 42 to 45 detects the first state quantity of the working fluid discharged from the hydraulic pump 41, that is, the discharge pressure. In addition, any one of the plurality of sensors 42 to 45 detects the second state quantity of the working fluid flowing on the downstream side of the hydraulic circuit 12D, that is, the suction pressure.

[0081] To explain in more detail, among the four sensors 42 and 43, when the working fluid is discharged from one port 41a of the hydraulic pump 41, at least the sensor 42 functions as an upstream sensor, and at least the sensor 44 functions as a downstream sensor. That is, the sensor 42 detects the first state quantity of the working fluid discharged from the hydraulic pump 41, that is, the discharge pressure, and the sensor 44 detects the second state quantity of the working fluid flowing on the downstream side of the hydraulic circuit 12D, that is, the suction pressure. On the other hand, when the working fluid is discharged from the other port 41b of the hydraulic pump 41, at least the sensor 44 functions as an upstream sensor, and at least the sensor 42 functions as a downstream sensor. That is, the sensor 44 detects the discharge pressure, and the sensor 42 detects the suction pressure.

[0082] <Control device> The control device 14D outputs a control signal to the on-off valves 48L and 48R. The control device 14 opens and closes the pump passages 47L and 47R by outputting a control signal to the on-off valves 48L and 48R. In addition, the control device 14D controls the operation of the motor 46. In more detail, the control device 14D controls the rotation direction and rotation speed of the motor 46. Thus, the control device 14D can control the discharge direction and discharge flow rate of the hydraulic pump 41.

[0083] In addition, the control device 14D as an example of an abnormality diagnosis device determines the abnormality of the hydraulic circuit 12D based on the discharge pressure and suction pressure of the hydraulic pump 41. In more detail, the control device 14D obtains the discharge pressure and suction pressure through the sensors 42 and 44. The control device 14 determines the abnormality of the hydraulic circuit 12 based on the comparison result of the discharge pressure and the suction pressure.

[0084] <Operation of the hydraulic circuit system> In the hydraulic circuit system 1D, in a state where a control signal is not output from the control device 14D to the on-off valves 48L and 48R (i.e., referred to as an "unpowered state"), the pump passages 47L and 47R are open. In the unpowered state, the control device 14D drives the motor 46 to discharge the working fluid from the hydraulic pump 41. As a result, the working fluid is supplied to the hydraulic actuator 3D, and the hydraulic actuator 3D operates. On the other hand, when a control signal is output from the control device 14D to the on-off valves 48L and 48R, or the driving of the motor 46 is stopped, the supply of the working fluid from the hydraulic pump 41 to the hydraulic actuator 3D stops. As a result, the operation of the hydraulic actuator 3D stops.

[0085] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1D, the control device 14D diagnoses an abnormality of the hydraulic circuit 12D based on the discharge pressure and the suction pressure. In more detail, the control device 14D diagnoses an abnormality of the hydraulic circuit 12D based on the comparison result of the discharge pressure and the suction pressure. In the present embodiment, the control device 14D diagnoses an abnormality of the hydraulic circuit 12D based on the pressure difference of the hydraulic pressure detected by the two sensors 42 and 43, that is, the first pressure difference, and the pressure difference of the hydraulic pressure detected by the two sensors 44 and 45, that is, the second pressure difference. The abnormality diagnosis method is described in further detail below.

[0086] In the hydraulic circuit system 1D, the control device 14D obtains the front and rear pressures of the throttles 47La and 47Ra of each pump passage 47L and 47R from the four sensors 42 to 45 when the hydraulic pump 41 is driven without being powered. The control device 14D calculates the front and rear pressure difference of the throttle 47La, i.e., the first pressure difference, and the front and rear pressure difference of the throttle 47Ra, i.e., the second pressure difference, based on the obtained front and rear pressures. In addition, the control device 14D compares the first pressure difference and the second pressure difference. The first pressure difference and the second pressure difference correspond to the flow rates flowing in and out of the hydraulic circuit system 1D, respectively. Therefore, the control device 14D can diagnose the abnormality of the hydraulic circuit 12D, more specifically, the leakage, based on the comparison result. For example, when the absolute value of the difference between the first pressure difference and the second pressure difference is less than a predetermined value, no large leakage occurs in the opening and closing valves 48L and 48R, the hydraulic actuator 3D, and the supply and discharge mechanism 49 of the hydraulic circuit 12D. Therefore, the control device 14D diagnoses that there is no abnormality in the hydraulic circuit 12D. On the other hand, when the absolute value of the difference between the first pressure difference and the second pressure difference is greater than a predetermined value, the outflow flow rate is small relative to the flow rate flowing into the hydraulic circuit 12D. Therefore, the control device 14D diagnoses that a large leakage has occurred in the hydraulic circuit 12D, that is, there is an abnormality in the hydraulic circuit 12D.

[0087] The hydraulic circuit system 1D of the fifth embodiment is a closed circuit, but has the same operational effects as the other open circuit hydraulic circuit systems 1 to 1C.

[0088] <Sixth embodiment> The hydraulic circuit system 1E of the sixth embodiment is as follows Fig.11 As shown, it is provided in the steering device 2. The steering device 2 is a device for steering a ship. The steering device 2 includes a steering gear 51 and a hydraulic circuit system 1E.

[0089] <Steering gear> The steering gear 51 works by receiving the supply of working fluid. The steering gear 51 changes the direction of the ship by working. The steering gear 51 includes a hydraulic actuator 52, a tiller 53, a rudder shaft 54 ​​and a rudder plate 55. The hydraulic actuator 52 is, for example, a ram cylinder, which has a plunger 52a and a pair of cylinders 52b and 52c. The plunger 52a is a rod-shaped member. A pair of cylinders 52b and 52c are provided at both end side portions of the plunger 52a. In addition, a pin 52e is provided at the central portion of the axial direction of the plunger 52a. The tiller 53 is fixed to the rudder shaft 54 ​​and engages with the pin 52e. The rudder shaft 54 ​​can rotate around its center. That is, the tiller 53 can rotate around the central axis of the rudder shaft 54. The rudder plate 55 is fixed to the tiller 53.

[0090] In the steering gear 51 thus constructed, when the hydraulic fluid is supplied to any one of the cylinders 52b and 52c of the hydraulic actuator 52, the plunger 52a moves forward or backward in one or the other axial direction. Then, the tiller 53 is pressed by the pin 52e. Thus, the tiller 53 rotates around the center of the rudder shaft 54. Then, the angle of the rudder plate 55, that is, the rudder angle, changes. In this way, the ship can be steered.

[0091] <Hydraulic circuit system> The hydraulic circuit system 1E operates the steering gear 51 by supplying working fluid to the steering gear 51. In more detail, the hydraulic circuit system 1E operates the steering plate 55 by supplying working fluid to the hydraulic actuator 52. The hydraulic circuit system 1E includes, for example, a plurality of hydraulic pumps 11L and 11R, a hydraulic circuit 12E, a plurality of downstream sensors 56L, 57L, 56R, and 57R, and a control device 14E. In addition, the hydraulic circuit system 1E also includes a plurality of upstream sensors 15L and 15R.

[0092] <Hydraulic pump> The plurality of hydraulic pumps 11L and 11R all discharge working fluid. In the present embodiment, two hydraulic pumps 11L and 11R are provided in the hydraulic circuit system 1E. The two hydraulic pumps 11L and 11R are positive displacement hydraulic pumps like the hydraulic pump 11 of the first embodiment. That is, the hydraulic pressure pulsation of the working fluid discharged by each of the two hydraulic pumps 11L and 11R. In the present embodiment, the two hydraulic pumps 11L and 11R are also swash plate pumps. However, the two hydraulic pumps 11L and 11R are not limited to swash plate pumps.

[0093] <Hydraulic circuit> The hydraulic circuit 12E is connected to both the hydraulic pumps 11L and 11R. In addition, the hydraulic circuit 12A is connected to the hydraulic actuator 52. The hydraulic circuit 12E controls the flow of the working fluid supplied from the hydraulic pumps 11L and 11R to the hydraulic actuator 52. In more detail, the hydraulic circuit 12E has a plurality of circuit systems 31L and 31R in order to provide redundancy in the supply of the working fluid to the hydraulic actuator 52. In the present embodiment, the hydraulic circuit 12E has the same number as the hydraulic pumps 11L and 11R, that is, two circuit systems 31L and 31R.

[0094] The two circuit systems 31L and 31R are connected to the hydraulic pumps 11L and 11R, respectively. In more detail, the first circuit system 31L is connected to the first hydraulic pump 11L, and the second circuit system 31R is connected to the second hydraulic pump 11R. In addition, the two circuit systems 31L and 31R have the same structure. Therefore, only the structure of the first circuit system 31L will be described below. For the structure of the second circuit system 31R, when the structure is the same as that of the first circuit system 31L, the symbol "L" of the same structure is replaced by "R" and the description is omitted.

[0095] The first circuit system 31L has two pump passages 61L and 62L, two supply and discharge passages 63L and 64L, a directional control valve 34L, and a supply and discharge mechanism 65L. The first pump passage 61L is connected to the suction port 11La of the first hydraulic pump 11L, and the second pump passage 62L is connected to the discharge port 11Lb of the first hydraulic pump 11L. In addition, a throttle 62La is interposed on the second pump passage 62L. In addition, the supply and discharge passages 63L and 64L are respectively connected to the first cylinder 52b and the second cylinder 52c of the hydraulic actuator 52. The directional control valve 34L is connected to the two pump passages 61L and 62L and the two supply and discharge passages 63L and 64L. The directional control valve 34L switches the connection objects of the four passages 61L~64L. As a result, the flow direction of the working fluid supplied from the first hydraulic pump 11L to the hydraulic actuator 52 is switched. That is, the directional control valve 34L can switch the supply destination of the working fluid of the first hydraulic pump 11L to any one of the two cylinders 52b and 52c of the hydraulic actuator 52. The supply and discharge mechanism 65L is connected to the supply and discharge passages 63L and 64L. The supply and discharge mechanism 65L supplies the working fluid that is insufficient during supply to the supply and discharge passages 63L and 64R, respectively. In addition, the supply and discharge mechanism 65L discharges the working fluid to the tank 25 when the hydraulic pressure of the supply and discharge passages 63L and 64R exceeds a predetermined pressure.

[0096] <Upstream sensor> A plurality of upstream side sensors 15L, 15R detect the first state quantity of the working fluid discharged from the hydraulic pumps 11L, 11R, respectively. In the present embodiment, the hydraulic circuit system 1A is provided with two upstream side sensors 15L, 15R, the same number as the hydraulic pumps 11L, 11R. Furthermore, the upstream side sensors 15L, 15R are connected to the second pump passages 62L, 62R of the circuit systems 31L, 31R, respectively. In more detail, the upstream side sensors 15L, 15R are connected to the upstream side of the throttles 62La, 62Ra in the second pump passage 62L. In the present embodiment, the upstream side sensors 15L, 15R are located at the most upstream side in the second pump passages 62L, 62R. In addition, the upstream side sensors 15L, 15R are hydraulic sensors in the present embodiment, and detect the discharge pressures of the hydraulic pumps 11L, 11R, respectively.

[0097] <Downstream sensor> The downstream side sensors 56L, 57L, 56R, 57R detect the second state quantity of the working fluid flowing on the downstream side of the hydraulic circuit 12E. In more detail, the downstream side sensors 56L, 57L detect the state quantity of the working fluid flowing on the downstream side of the first circuit system 31L. In addition, the downstream side sensors 56R, 57R detect the state quantity of the working fluid flowing on the downstream side of the second circuit system 31R. In the present embodiment, the downstream side sensors 56L, 57L are connected to the supply and discharge passages 63L, 64R of the first circuit system 31L, respectively. In addition, the downstream side sensors 56R, 57R are connected to the supply and discharge passages 63R, 64R of the second circuit system 31R, respectively. The downstream side sensors 56L, 57L, 56R, 57R are pressure sensors in the present embodiment, and detect the hydraulic pressure of the working fluid flowing in the connected supply and discharge passages 63L, 64L, 63R, 64R. Thus, the downstream side sensors 56L, 57L, 56R, 57R detect the hydraulic pressure of the working fluid on the downstream side of the circuit systems 31L, 31R, that is, the downstream pressure. The downstream side sensors 56L, 57L, 56R, 57R may also be flow sensors.

[0098] <Control device> The control device 14E has a function similar to that of the control device 14A. That is, the control device 14E controls the operation of the directional control valves 34L and 34R by outputting control signals. In more detail, the control device 14 outputs first and second control signals according to a program or the like. By outputting the first control signal, the directional control valve 34L is operated, and by outputting the second control signal, the directional control valve 34R is operated.

[0099] In addition, the control device 14E as an example of an abnormality diagnosis device determines the abnormality of the hydraulic circuit 12E based on the discharge pressure of the first hydraulic pump 11L and the second hydraulic pump 11R and the downstream pressure detected by the downstream side sensors 56L, 57L, 56R, 57R. In more detail, the control device 14 obtains the downstream pressure from the downstream side sensors 56L, 57L, 56R, 57R, and obtains the discharge pressure from the two upstream side sensors 15L, 15R. And the control device 14 determines the abnormality of the hydraulic circuit 12E based on the comparison result of the obtained downstream pressure and the two discharge pressures. In the present embodiment, the control device 14 determines the abnormality of the hydraulic circuit 12E (in more detail, the abnormality of the circuit system 31L, 31R) based on the waveform data of the downstream pressure and the waveform data of the two discharge pressures.

[0100] <Operation of the hydraulic circuit system> In the hydraulic circuit system 1E, the control device 14E outputs a first control signal and a second control signal according to a program or the like. As a result, the first directional control valve 34L and the second directional control valve 34R operate. Then, the working fluid is supplied from the first hydraulic pump 11L to the hydraulic actuator 52 via the first pump passage 61L and the supply and discharge passage 63L (or the supply and discharge passage 64L). In addition, the working fluid is also supplied from the second hydraulic pump 11R to the hydraulic actuator 52 via the first pump passage 61R and the supply and discharge passage 63R (or the supply and discharge passage 64R). As a result, the plunger 52a moves, and thus the steering angle of the steering plate 52d changes. Therefore, the direction of the ship can be changed by the steering gear 51.

[0101] <Diagnosis of abnormality in hydraulic circuit system> In the hydraulic circuit system 1E, the control device 14E diagnoses an abnormality of the hydraulic circuit 12E based on the discharge pressure and the downstream pressure. In more detail, in the hydraulic circuit system 1E, the control device 14E diagnoses an abnormality of the hydraulic circuit 12E based on the comparison result of the discharge pressure and the downstream pressure in each circuit system 31L, 31R. In the present embodiment, the control device 14 diagnoses an abnormality of the hydraulic circuit 12E based on the waveform data of the discharge pressure, the waveform data of the downstream pressure, and the control signal in each circuit system 31L, 31R. The abnormality diagnosis method is described in further detail below.

[0102] In the hydraulic circuit system 1E, the control device 14E outputs the first and second control signals. At this time, the control device 14E obtains the discharge pressure from the upstream sensors 15L and 15R, respectively, and obtains the downstream pressure of the circuit system 31L and 31R from the downstream sensors 56L, 57L, 56R and 57R. In addition, the control device 14E generates waveform data of the discharge pressure based on the two obtained discharge pressures, and generates waveform data of the downstream pressure based on the obtained downstream pressure. The control device 14E compares the generated waveform data of the discharge pressure with the waveform data of the discharge pressure. The control device 14E diagnoses abnormality of the hydraulic circuit 12 based on the comparison result.

[0103] For example, the control device 14E outputs the first and second control signals, whereby the two directional control valves 34L and 34R respectively connect the second pump passages 62L and 62R to the supply and exhaust passages 63L and 63R. The control device 14E obtains the discharge pressure obtained from the upstream side sensors 15L and 15R. And the control device 14E generates waveform data of the discharge pressure based on the obtained discharge pressure. In addition, the control device 14E obtains the downstream pressure of the circuit system 31L and 31R from the downstream side sensors 56L, 57L, 56R and 57R. And the control device 14E generates waveform data of the downstream pressure based on the obtained downstream pressure. In more detail, the control device 14E generates waveform data of the downstream pressure of the circuit system 31L and 31R based on the hydraulic pressure of the working fluid flowing in the supply passages 63L, 64L, 63R and 64L connected to the second pump passages 62L and 62R. That is, the control device 14E selects the supply and discharge passages 63L, 64L, 63R, 64L to obtain the hydraulic pressure based on the output first and second control signals. And the control device 14E obtains the hydraulic pressure of the working fluid flowing in the selected supply and discharge passages 63L, 64L, 63R, 64L as the downstream pressure. The control device 14E diagnoses the abnormality of the first circuit system 31L based on the comparison result of the waveform data of the discharge pressure of the first hydraulic pump 11L and the waveform data of the downstream pressure of the first circuit system 31L. In addition, the control device 14E diagnoses the abnormality of the second circuit system 31R based on the comparison result of the waveform data of the discharge pressure of the second hydraulic pump 11R and the waveform data of the downstream pressure of the second circuit system 31R.

[0104] For example, when the pulsation in the waveform data of the downstream pressure is almost not attenuated relative to the pulsation in the waveform data of the discharge pressure, the control device 14E determines that the first circuit system 31L is normal. On the other hand, when the pulsation in the waveform data of the downstream pressure is attenuated relative to the pulsation in the waveform data of the discharge pressure, it is determined that there is a leakage in the first circuit system 31L. In addition, when there is no pulsation in the waveform data of the downstream pressure relative to the pulsation in the waveform data of the discharge pressure, the control device 14E determines that there is an abnormality in the first circuit system 31L in which the working fluid cannot be supplied. Similarly, the control device 14E compares the waveform data of the discharge pressure of the second hydraulic pump 11R with the waveform data of the downstream pressure of the supply and discharge passage 63R, thereby diagnosing the abnormality of the second circuit system 31R based on the comparison result.

[0105] In addition, the control device 14E also diagnoses abnormalities of the hydraulic circuit 12E based on the waveform data in the non-energized state in which the first and second control signals are not output. An example of abnormality diagnosis is described below. The control device 14E determines that the first circuit system 31L is normal when there is no pulsation in the waveform data of the downstream pressure relative to the pulsation in the waveform data of the discharge pressure. On the other hand, the control device 14E determines that the first circuit system 31L is abnormal, such as the direction control valve 34L is stuck and cannot operate, when there is pulsation in the waveform data of the downstream pressure relative to the pulsation in the waveform data of the discharge pressure. Similarly, the control device 14E diagnoses abnormalities of the second circuit system 31R based on the comparison result of the waveform data of the discharge pressure of the second hydraulic pump 11R and the waveform data of the downstream pressure.

[0106] The hydraulic circuit system 1E of the sixth embodiment configured in this way can diagnose abnormality of the hydraulic circuit 12E including the plurality of circuit systems 31L and 31R in the steering device 2. Therefore, the steering device 2 having the above-mentioned functions can be realized.

[0107] Otherwise, the hydraulic circuit system 1E achieves the same operational effects as those of the hydraulic circuit system 1A of the second embodiment.

[0108] <Other embodiments> In the hydraulic circuit systems 1, 1A~1E of the first to sixth embodiments, the downstream pressure and the discharge pressure can also be corrected when generating waveform data. For example, a throttle (for example, a fixed throttle) is provided in the liquid passage 21, 21A. The pressure before and after the throttle is detected by a sensor, thereby estimating the viscosity of the working fluid. And, after correcting the downstream pressure and the discharge pressure by the estimated viscosity, the waveform data is generated. In addition, in addition to the viscosity, the downstream pressure and the discharge pressure can also be corrected by the pressure loss of the piping, etc. By correcting the downstream pressure and the discharge pressure in this way, the diagnostic accuracy of the abnormality of the hydraulic circuit 12, 12A, 12E can be improved.

[0109] In addition, in the hydraulic circuit systems 1, 1A to 1E of the first to sixth embodiments, the state quantity for diagnosing the abnormality of the hydraulic circuit 12, 12A, 12D, 12E is the hydraulic pressure of the working fluid, but it may also be the flow rate of the working fluid. In addition, the flow rate of the working fluid does not necessarily need to be directly measured by a sensor, and may also be estimated based on the detected hydraulic pressure of the working fluid.

[0110] In the hydraulic circuit systems 1, 1A to 1E of the first to sixth embodiments, other hydraulic circuits and hydraulic control devices (e.g., valves and throttles) may be interposed or connected between the hydraulic circuits 12, 12A, 12D, 12E and the hydraulic actuators 3, 52. In addition, the hydraulic control devices are not limited to the aforementioned cut-off valves 22, 23 and the directional control valves 34, 34A, 34L, 34R, but may be other valves and throttles. In addition, the control devices 14, 14A, 14B, 14E may also diagnose abnormalities of the hydraulic circuits 12, 12A, 12E based on a first state quantity (e.g., discharge pressure) pre-set by prior measurement or the like. In more detail, the control devices 14, 14A, 14B, 14E may also diagnose abnormalities of the hydraulic circuits 12, 12A, 12E by comparing waveform data of the pre-set discharge pressure with waveform data of the detected downstream pressure.

[0111] The hydraulic circuit systems 1A to 1C and 1E of the second to fourth and sixth embodiments may also include a plurality of hydraulic pumps of more than three. In this case, the control device diagnoses the abnormality of the hydraulic circuit based on the plurality of first state quantities and the second state quantity. In addition, the hydraulic circuits 12A and 12E may also include more than three circuit systems. Moreover, a plurality of circuit systems may be connected to one hydraulic pump.

[0112] <Exemplary embodiment> The hydraulic circuit system in the first aspect comprises: at least one positive displacement pump; a hydraulic circuit connected to the pump; a downstream sensor that detects the state quantity of the working fluid flowing on the downstream side of the hydraulic circuit; and an abnormality diagnosis device that determines the abnormality of the hydraulic circuit based on the comparison result of the first state quantity of the working fluid discharged from the pump and the second state quantity of the working fluid detected by the downstream sensor. According to the above aspect, it is possible to find the change in the state quantity of the working fluid flowing in the hydraulic circuit based on the first state quantity of the working fluid discharged from the pump and the second state quantity of the working fluid detected by the downstream sensor. And it is possible to determine the abnormality in the hydraulic circuit based on the change in the hydraulic pressure.

[0113] The hydraulic circuit system of the second aspect is the hydraulic circuit system of the first aspect, wherein the hydraulic circuit of the first aspect includes at least one hydraulic control device that controls the flow of the working fluid from the pump. According to the above aspect, an abnormality of the hydraulic control device included in the hydraulic circuit can be determined.

[0114] The hydraulic circuit system of the third aspect is the hydraulic circuit system of the second aspect, further comprising a control device that outputs a control signal to the hydraulic control device, and the abnormality diagnosis device determines the abnormality of the hydraulic control device based on the comparison result of the control signal output from the control device, the first state quantity and the second state quantity. According to the above aspect, it is possible to determine the abnormality related to the response of the hydraulic control device to the control signal.

[0115] In the hydraulic circuit system of the fourth aspect, in the hydraulic circuit system of any one of the first to third aspects, the abnormality diagnosis device determines the abnormality of the hydraulic circuit based on the waveform data of the first state quantity and the second state quantity. According to the above aspect, the case of diagnosis based on the waveform data of the first state quantity and the waveform data of the second state quantity is easier to find the qualitative change of the downstream pressure relative to the discharge pressure than the case of diagnosis based only on the first state quantity and the second state quantity. Therefore, the control device can easily perform abnormality judgment of the hydraulic circuit.

[0116] The hydraulic circuit system in the fifth aspect is provided with a plurality of the pumps in the hydraulic circuit system in the first aspect, the hydraulic circuit makes the working fluids discharged from the plurality of pumps merge, and the abnormality diagnosis device determines the abnormality of the hydraulic circuit based on the plurality of first state quantities of the working fluids discharged from the plurality of pumps and the second state quantity detected by the downstream sensor. According to the above aspect, it is possible to confirm whether the working fluids discharged from each pump are supplied to the downstream side of the hydraulic circuit based on the plurality of first state quantities of the working fluids discharged from the plurality of pumps and the second state quantity detected by the downstream sensor. Thus, the abnormality diagnosis device can determine which pump in the hydraulic circuit has failed to merge working fluids.

[0117] The hydraulic circuit system in the sixth aspect is the hydraulic circuit system in the fifth aspect, wherein the hydraulic circuit has: a plurality of circuit systems, each of which is connected to the plurality of pumps; and a confluence passage, which causes the working fluid flowing in the plurality of circuit systems to merge, the downstream side sensor detects a second state quantity of the working fluid flowing on the downstream side of the confluence passage, and the abnormality diagnosis device determines the abnormality of the circuit system based on a plurality of first state quantities of the working fluid discharged from the plurality of pumps and a second state quantity detected by the downstream side sensor. According to the above aspect, it is possible to confirm whether the working fluid discharged from each pump is supplied to the downstream side of the hydraulic circuit via each circuit system by comparing a plurality of first state quantities of the working fluid discharged from the plurality of pumps and a second state quantity detected by the downstream side sensor. Thus, it is possible to diagnose and determine the abnormality of the circuit system.

[0118] The hydraulic circuit system in the seventh aspect is the hydraulic circuit system in the sixth aspect, wherein the abnormality diagnosis device determines the abnormality of the hydraulic circuit based on the waveform data related to the plurality of first state quantities of the working fluid respectively discharged from the plurality of pumps. According to the above aspect, the waveform data related to the plurality of first state quantities of the working fluid respectively discharged from the plurality of pumps is taken into consideration. Therefore, it is possible to facilitate the abnormality diagnosis of each circuit system.

[0119] The hydraulic circuit system in the eighth aspect is the hydraulic circuit system in the sixth aspect, further comprising a signal generator provided in at least one of the plurality of pumps, which changes the first state quantity of the working fluid discharged from the pump, thereby adding an additional signal to the working fluid, and the abnormality diagnosis device determines the abnormality of the circuit system based on the first state quantity to which the additional signal is added. According to the above aspect, by detecting the additional signal, it is possible to confirm whether the working fluid discharged from each pump reaches the downstream side of the hydraulic circuit via each circuit system.

[0120] The hydraulic circuit system in the ninth aspect is a hydraulic circuit system in any one of the first to eighth aspects, further comprising an upstream sensor that detects a first state quantity of the working fluid discharged from the pump, and the abnormality diagnosis device determines the abnormality of the hydraulic circuit based on the first state quantity detected by the upstream sensor and the second state quantity of the working fluid detected by the downstream sensor. According to the above aspect, the control device determines the abnormality of the hydraulic circuit based on the actual state quantities on the upstream side and the downstream side of the hydraulic circuit. Therefore, the control device can improve the accuracy of determining the abnormality of the hydraulic circuit.

[0121] The steering device includes the hydraulic circuit system with an abnormality diagnosis function according to any one of the first to ninth aspects. According to the above aspect, a steering device having the above-mentioned function can be realized.

[0122] According to the above description, many improvements and other embodiments of the present invention are clear to those skilled in the art. Therefore, the above description should only be interpreted as an example, and is provided for the purpose of teaching the best mode of performing the present invention to those skilled in the art. As long as it does not depart from the gist of the present invention, its specific structure and / or function can be substantially changed.

Claims

1. A hydraulic circuit system with abnormality diagnosis function, characterized in that: have: at least one positive displacement pump; a hydraulic circuit connected to the pump; a downstream side sensor that detects a state quantity of a working fluid flowing on a downstream side of the hydraulic circuit; as well as The abnormality diagnosis device determines an abnormality of the hydraulic circuit based on a comparison result between a first state quantity of the hydraulic fluid discharged from the pump and a second state quantity of the hydraulic fluid detected by the downstream sensor.

2. The hydraulic circuit system with abnormality diagnosis function according to claim 1, characterized in that: The hydraulic circuit includes at least one hydraulic control device that controls the flow of working fluid from the pump.

3. The hydraulic circuit system with abnormality diagnosis function according to claim 2, characterized in that: A control device is also provided to output a control signal to the hydraulic control device, The abnormality diagnosis means determines an abnormality of the hydraulic control device based on a control signal output from the control means, and a comparison result of a first state quantity and a second state quantity.

4. The hydraulic circuit system with abnormality diagnosis function according to claim 1, characterized in that: The abnormality diagnosis device determines abnormality of the hydraulic circuit based on waveform data of a first state quantity and a second state quantity.

5. The hydraulic circuit system with abnormality diagnosis function according to claim 1, characterized in that: A plurality of the pumps are provided, The hydraulic circuit merges the working fluids discharged from the plurality of pumps. The abnormality diagnosis device determines an abnormality of the hydraulic circuit based on a plurality of first state quantities of the hydraulic fluid discharged from the plurality of pumps and a second state quantity detected by the downstream sensor.

6. The hydraulic circuit system with abnormality diagnosis function according to claim 5, characterized in that: The hydraulic circuit includes: a plurality of circuit systems to which the plurality of pumps are connected respectively; and a merging passage for merging the working fluids flowing in the plurality of circuit systems. The downstream sensor detects a second state quantity of the working fluid flowing on the downstream side of the merging passage. The abnormality diagnosis device determines abnormality of the circuit system based on a plurality of first state quantities of the hydraulic fluid discharged from the plurality of pumps and a second state quantity detected by the downstream sensor.

7. The hydraulic circuit system with abnormality diagnosis function according to claim 6, characterized in that: The abnormality diagnosis device determines abnormality of the hydraulic circuit based on waveform data related to a plurality of first state quantities of the hydraulic fluid discharged from the plurality of pumps, respectively.

8. The hydraulic circuit system with abnormality diagnosis function according to claim 6, characterized in that: A signal generator is further provided, which is provided at least one of the plurality of pumps and changes a first state quantity of the working fluid discharged from the pump to add an additional signal to the working fluid. The abnormality diagnosis device determines the abnormality of the circuit system based on the first state quantity to which the additional signal is added.

9. The hydraulic circuit system with abnormality diagnosis function according to claim 1, characterized in that: The device further comprises an upstream sensor for detecting a first state quantity of the working fluid discharged from the pump. The abnormality diagnosis device determines an abnormality of the hydraulic circuit based on a first state quantity detected by the upstream sensor and a second state quantity of the hydraulic fluid detected by the downstream sensor.

10. A steering device, characterized in that: A hydraulic circuit system with an abnormality diagnosis function according to any one of claims 1 to 9.

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