Hydraulic supply device and hydraulic supply method

Abstract

To be solved is to provide a hydraulic supply device and a hydraulic supply method that can supply hydraulic pressure of a constant pressure for a certain period of time even if some failure occurs in a hydraulic system to be connected. According to the present invention, the hydraulic supply device includes: a first connection line 11; a pump 2 that delivers hydraulic oil to the first connection line 11; a second connection line 12 to which hydraulic oil is supplied from the first connection line 11; a third connection line 13 to which hydraulic oil is returned from the second connection line 12; an accumulator 3 connected to the first connection line 11; a pressure reducing valve 4 that reduces the pressure of hydraulic oil introduced from the first connection line 11 and then supplies the hydraulic oil to the second connection line 12; and a valve device 5 that discharges hydraulic oil from the first connection line 11 to the third connection line 13, wherein the second connection line 12 is connected to the first connection line 11 only through the pressure reducing valve 4, and the valve device 5 is switched from a state in which hydraulic oil in the first connection line 11 is not discharged to the third connection line 13 to a state in which hydraulic oil in the first connection line 11 is discharged to the third connection line 13 when the pressure of the hydraulic oil in the first connection line 11 is greater than a first pressure.

Description

Technical Field

[0001] This invention relates to a hydraulic supply device and a hydraulic supply method. Background Technology

[0002] JP 2015-028367 A describes a hydraulic unit as a hydraulic supply device. This hydraulic unit includes a hydraulic pump, an accumulator for storing hydraulic oil discharged from the hydraulic pump, and a leak-free pressure reducing valve. The leak-free pressure reducing valve interconnects a main connection line for introducing hydraulic oil from the accumulator and a secondary connection line for discharging the introduced hydraulic oil. Simultaneously, the leak-free pressure reducing valve regulates the pressure of the hydraulic oil in the secondary connection line to a lower pressure than that in the main connection line. According to this pressure unit, the hydraulic oil pressure is sufficiently increased by the hydraulic pump and stored in the accumulator, and can be supplied to an actuator connected to the pressure unit at the required pressure through the leak-free pressure reducing valve, thereby reducing the number of hydraulic pump drives and significantly improving energy efficiency.

[0003] In a hydraulic supply device (hydraulic unit) as described in JP 2015-028367A, if any fault (e.g., oil leakage) exists in the hydraulic system from which hydraulic fluid is supplied, the pump is driven more frequently, and the temperature of the hydraulic fluid may rise. Furthermore, the hydraulic supply device may be unable to supply hydraulic fluid at a constant pressure. In these cases, the machine tool, which operates using hydraulic fluid supplied from the hydraulic supply device, may not operate normally as intended, and the machine tool may have to be stopped. Therefore, it is desirable to provide a hydraulic supply device and a hydraulic supply method that can supply hydraulic fluid at a constant pressure for a certain period of time (e.g., until the end of the machine tool operation process) even if certain faults occur in the hydraulic system. Summary of the Invention

[0004] In view of this reality, the object of the present invention is to provide a hydraulic supply device and a hydraulic supply method that can supply hydraulic pressure at a constant pressure for a certain period of time even if certain faults occur in the connected hydraulic system.

[0005] To achieve the above objectives, the hydraulic supply device according to the present invention includes:

[0006] First connecting pipe;

[0007] Pump, which delivers hydraulic oil to the first connecting pipeline;

[0008] The second connecting pipeline is used to supply hydraulic oil from the first connecting pipeline to the second connecting pipeline;

[0009] The third connecting pipe is used to return the hydraulic oil from the second connecting pipe to the third connecting pipe;

[0010] An accumulator, connected to the first connecting line, to store the hydraulic oil delivered from the pump;

[0011] A pressure reducing valve reduces the pressure of the hydraulic oil introduced from the first connecting line, and then supplies the hydraulic oil to the second connecting line;

[0012] and a valve device that discharges the hydraulic oil from the first connecting line to the third connecting line, wherein

[0013] The second connecting pipe is connected to the first connecting pipe only through the pressure reducing valve.

[0014] Furthermore, when the pressure of the hydraulic oil in the first connecting pipeline is equal to or greater than the first pressure, the valve device switches from a state of not discharging the hydraulic oil in the first connecting pipeline to the state of discharging the hydraulic oil in the first connecting pipeline to the third connecting pipeline.

[0015] To achieve the above objectives, the hydraulic supply method according to the present invention includes:

[0016] The hydraulic oil delivery process involves delivering hydraulic oil to the first connecting pipeline.

[0017] The supply process involves supplying hydraulic oil from the first connecting pipeline to the second connecting pipeline.

[0018] The return process involves returning the hydraulic oil from the second connecting line to the third connecting line.

[0019] During the pressure accumulating process, the hydraulic oil delivered from the pump to the first connecting pipeline is stored in the accumulator.

[0020] The pressure-reducing supply process involves introducing hydraulic oil into the first connecting pipeline, reducing the pressure of the hydraulic oil, and then supplying the hydraulic oil to the second connecting pipeline.

[0021] and a discharge process, wherein the hydraulic oil is discharged from the first connecting pipe to the third connecting pipe, wherein

[0022] The pressure-reducing supply process only supplies the hydraulic oil, which has been introduced into and depressurized from the first connecting pipeline, to the second connecting pipeline.

[0023] Furthermore, if the pressure of the hydraulic oil in the first connecting pipeline is equal to or greater than the first pressure, the discharge process switches from a state where the hydraulic oil in the first connecting pipeline is not discharged to the third connecting pipeline to a state where the hydraulic oil in the first connecting pipeline is discharged to the third connecting pipeline.

[0024] According to the hydraulic supply device and hydraulic supply method of the present invention, even if certain faults occur in the connected hydraulic system, a constant pressure of hydraulic fluid can be supplied for a certain period of time. Attached Figure Description

[0025] Figure 1 This is a hydraulic circuit diagram of the hydraulic supply device according to this embodiment; and

[0026] Figure 2 This is a cross-sectional view of the valve assembly structure. Detailed Implementation

[0027] The hydraulic supply device and hydraulic supply method related to the present invention will now be described with reference to the accompanying drawings.

[0028] Figure 1 This is a hydraulic circuit diagram of the hydraulic supply device according to this embodiment.

[0029] First, an overview of the hydraulic supply device according to this embodiment will be described. The hydraulic supply device of this embodiment includes: a first connecting line 11; a pump 2 that delivers hydraulic oil to the first connecting line 11; a second connecting line 12 from which hydraulic oil is supplied from the first connecting line 11 to the second connecting line 12; a third connecting line 13 from which hydraulic oil returns from the second connecting line 12 to the third connecting line 13; an accumulator 3 connected to the first connecting line 11 to store the hydraulic oil delivered from the pump 2; a pressure reducing valve 4 that reduces the pressure of the hydraulic oil introduced from the first connecting line 11 and then supplies the hydraulic oil to the second connecting line 12; and a valve device 5 that discharges hydraulic oil from the first connecting line 11 to the third connecting line 13. The second connecting line 12 is connected to the first connecting line 11 only through the pressure reducing valve 4.

[0030] When the pressure of the hydraulic oil in the first connecting line 11 is equal to or greater than the first pressure (e.g., 16 MPa), the valve device 5 switches from a state of not discharging the hydraulic oil in the first connecting line 11 to the state of discharging the hydraulic oil in the first connecting line 11 to the third connecting line 13.

[0031] The hydraulic supply device according to this embodiment includes: a hydraulic oil conveying process, wherein the hydraulic oil conveying process conveys hydraulic oil to a first connecting pipe 11; a supply process, wherein the supply process supplies hydraulic oil from the first connecting pipe 11 to a second connecting pipe 12; a pressure accumulating process, wherein the pressure accumulating process stores the hydraulic oil conveyed from the pump 2 to the first connecting pipe 11 in an accumulator 3; a pressure reducing supply process, wherein the pressure reducing supply process introduces hydraulic oil from the first connecting pipe 11, reduces the pressure of the hydraulic oil, and then supplies the hydraulic oil to the second connecting pipe 12; and a discharge process, wherein the discharge process discharges hydraulic oil from the first connecting pipe 11 to a third connecting pipe 13. This enables a hydraulic supply method in which the pressure reducing supply process supplies only the hydraulic oil introduced from and depressurized from the first connecting pipe 11 to the second connecting pipe 12, and if the pressure of the hydraulic oil in the first connecting pipe 11 is equal to or greater than a first pressure, the discharge process switches from a state where the hydraulic oil in the first connecting pipe 11 is not discharged to the third connecting pipe 13 to a state where the hydraulic oil in the first connecting pipe 11 is discharged to the third connecting pipe 13.

[0032] The following is a detailed description of the hydraulic supply device and hydraulic supply method according to this embodiment. In the following description, the downstream side in the hydraulic oil flow direction may be simply referred to as the downstream side. For example, the second connecting pipe 12, which supplies hydraulic oil to the first connecting pipe 11, is a connecting pipe connected to the downstream side of the first connecting pipe 11.

[0033] Pump 2 is a supply device for the hydraulic oil delivery process, in which it delivers hydraulic oil stored in tank 71 to first connecting line 11. Pump 2 is connected to inlet connecting line 10 and first connecting line 11, which introduce hydraulic oil stored in tank 71. Pump 2 draws hydraulic oil from tank 71 via inlet connecting line 10 and then delivers it to first connecting line 11. Pump 2 may be driven, for example, by electric motor 21.

[0034] The first connecting line 11 is the connecting line that supplies hydraulic oil to the pressure reducing valve 4. As described below, the accumulator 3 and the valve device 5 are connected to the first connecting line 1.

[0035] The pressure reducing valve 4 is a valve mechanism that implements a pressure-reducing supply process, which lowers the pressure of the hydraulic oil supplied from the first connecting line 11 (hereinafter referred to as "hydraulic pressure"), and then supplies the hydraulic oil to the second connecting line 12. The pressure reducing valve 4 reduces the hydraulic pressure in the first connecting line 11 to a predetermined control pressure (e.g., 10 MPa), and then supplies the hydraulic oil to the second connecting line 12. The pressure reducing valve 4 should preferably be a so-called leak-free pressure reducing valve.

[0036] The second connecting line 12 is a connecting line that delivers hydraulic oil to the hydraulic system connected to the hydraulic supply device. Furthermore, the hydraulic system is a hydraulic circuit on the factory or machine tool that supplies hydraulic oil to the hydraulic drive unit in the machine tool.

[0037] The third connecting line 13 is a connecting line that returns hydraulic oil supplied to the hydraulic system and hydraulic oil from the first connecting line 11 or the second connecting line 12 to the tank 71 (an example of a return process). In this embodiment, as an example, the third connecting line 13 includes a first return line 14 that returns hydraulic oil supplied to the hydraulic system to the tank 71 or returns hydraulic oil from the second connecting line 12 to the tank 71, and a second return line 15 that returns hydraulic oil from the first connecting line 11 to the tank 71. Figure 1 As shown, the first return line 14 and the second return line 15 can merge on the downstream side (the side closer to tank 71).

[0038] Accumulator 3 is a pressure accumulator device that performs a pressure accumulation process, which stores the pressure energy of the hydraulic oil in the first connecting pipe 11. Accumulator 3 may have a gas-filled container, and hydraulic oil can be stored by pushing hydraulic oil into the gas-filled container. In such an accumulator 3, the hydraulic oil compresses the gas, and the container is filled with a volume of hydraulic oil equivalent to the thrust (pressure). In accumulator 3, when the hydraulic pressure in the first connecting pipe 11 drops below the hydraulic pressure in the accumulator, the hydraulic oil stored in accumulator 3 is released into the first connecting pipe 11, thereby reducing the hydraulic pressure drop in the first connecting pipe 11. Accumulator 3 is located in the first connecting pipe 11 between pressure reducing valve 4 and valve device 5. In other words, accumulator 3 is connected to the downstream section 11b of the first connecting pipe, which is a portion of the first connecting pipe 11 located downstream of valve device 5.

[0039] Valve device 5 is a valve mechanism for switching. If the hydraulic pressure in the downstream section 11b of the first connecting pipe is equal to or greater than the first pressure, the valve mechanism switches from a state of not discharging hydraulic oil in the upstream section 11a of the first connecting pipe to a state of discharging hydraulic oil in the upstream section 11a of the first connecting pipe to the third connecting pipe 13 (example of the discharge process). The upstream section 11a of the first connecting pipe is a portion of the first connecting pipe 11 located upstream of valve device 5.

[0040] Figure 2An example of the structure of valve device 5 is shown. Valve device 5 has: a first connection port 57, which is supplied with hydraulic oil by an upstream section 11a of a first connection pipeline; a second connection port 58, which returns the hydraulic oil supplied from the upstream section 11a of the first connection pipeline to a downstream section 11b of the first connection pipeline 11; a third connection port 59, which discharges the hydraulic oil supplied from the upstream section 11a of the first connection pipeline to a second return pipeline 15; a check valve 51, which prevents hydraulic oil from flowing back from the second connection port 58 to the first connection port 57; and a switching valve 52, which switches between a state in which the first connection port 57 and the third connection port 59 are connected to each other and a state in which they are not connected to each other.

[0041] The check valve 51 has a valve body 51a supported by an elastic component such as a spring 51b.

[0042] In check valve 51, if the flow rate of hydraulic oil from the upstream side (upstream section 11a of the first connecting pipeline, first connecting port 57) to the downstream side (downstream section 11b of the first connecting pipeline, second connecting port 58) of check valve 51 is equal to or greater than a predetermined amount (equal to or greater than a predetermined pressure difference), then valve body 51a moves to a position that connects the first connecting port 57 and the second connecting port 58, i.e., the check valve 51 is open. (Refer to...) Figure 2 In this case, the valve body 51a is in a state away from the valve seat 51c (i.e., the check valve 51 is in the open position), and the first connection port 57 and the second connection port 58 are connected to each other.

[0043] When the flow rate of hydraulic oil from the upstream side to the downstream side of check valve 51 becomes less than a predetermined amount (i.e., the differential pressure drops below a predetermined level), valve body 51a moves to the closed position, thereby blocking the flow path connecting the first connection port 57 and the second connection port 58, at which point check valve 51a becomes closed. This prevents hydraulic oil from flowing back from the downstream side of check valve 51 to the upstream side. Figure 2 The diagram shows a situation where the valve body 51a contacts the valve seat 51c disposed between the first connection port 57 and the second connection port 58, thereby blocking the flow path connecting the first connection port 57 and the second connection port 58 (the check valve 51 is in the closed state).

[0044] In check valve 51, if the flow rate of hydraulic oil from first connection port 57 to second connection port 58 exceeds a predetermined amount, the flowing hydraulic oil pushes the valve body 51a in the direction of opening check valve 51 against the spring 51b pushing the valve body 51 in the direction of closing check valve 51, thereby keeping check valve 51 in the open state to maintain the first connection port 57 and the second connection port 58 in a connected state. This allows hydraulic oil to flow from the first connection port 57 to the second connection port 58.

[0045] In check valve 51, if the flow rate of hydraulic oil from the first connection port 57 to the second connection port 58 is less than a predetermined amount, the spring 51b pushes the valve body 51a in the direction of closing check valve 51, resisting the push of hydraulic oil attempting to flow through check valve 51 in the direction of opening check valve 51, thereby closing check valve 51 and keeping the first connection port 57 and the second connection port 58 in a closed state. This prevents hydraulic oil from flowing from the first connection port 57 to the second connection port 58.

[0046] The switching valve 52 is a valve mechanism that is normally in the closed state. In this closed state, the first connection port 57 and the third connection port 59 are not connected. However, when the hydraulic pressure in the downstream section 11b of the first connection line rises and exceeds a first pressure, the valve mechanism switches to the open state, connecting the first connection port 57 and the third connection port 59. Furthermore, when the hydraulic pressure in the downstream section 11b of the first connection line drops below a first return pressure (e.g., 13.6 MPa), the switching valve 52 switches from the open state to the closed state, where the first return pressure is lower than the first pressure. In this embodiment, when the switching valve 52 is in the open state and the first connection port 57 and the third connection port 59 are connected, the flow rate of hydraulic oil from the upstream side to the downstream side of the check valve 51 becomes less than a predetermined amount, and the check valve 51 is in the closed state.

[0047] The switching valve 52 includes: a cylinder portion 52a connected to a first connection port 57 and a third connection port 59; a piston 52b housed within the cylinder portion 52b; an elastic member, such as a spring 52c, that pushes one end of the piston 52b in the extending direction of the cylinder portion 52c; and a pressure transmission connection line 53 connecting the other end of the piston 52b in the cylinder portion 52a (the side away from the spring 52c) to the first connection port 57. The first connection port 57 is connected to the other end of the piston 52b in the cylinder portion 52a (the side away from the spring 52c). The third connection port 59 is connected to one end of the piston 52b in the cylinder portion 52a (the side closer to the spring 52c). In other words, the piston 52b is pushed by the spring 52c from the side closer to the third connection port 59 to the side closer to the first connection port 57.

[0048] When the switching valve 52 is opened, the hydraulic pressure (i.e. the first pressure) in the downstream section 11b of the first connecting pipe can be adjusted by the spring constant of the spring 52c.

[0049] If the hydraulic pressure in the downstream section 11b of the first connecting pipe is less than the first pressure in the open state, the switching valve 52 operates such that the thrust of the spring 52c is greater than the thrust of the hydraulic oil transmitted through the pressure transmission connecting pipe 53, thereby pushing the piston 52b away from the spring 52c. Thus, when the hydraulic pressure in the downstream section 11b of the first connecting pipe is less than the first pressure when the switching valve 52 is in the open state, the piston 52b remains in the cylinder portion 52a in a position blocking either the first connecting port 57 or the third connecting port 59, thereby preventing hydraulic oil from flowing from the first connecting port 57 to the third connecting port 59.

[0050] In the switching valve 52, if the hydraulic pressure in the downstream section 11b of the first connecting pipe exceeds the first pressure in the open state, the thrust of the hydraulic oil transmitted through the pressure transmission connecting pipe 53, which pushes the piston 52b towards the side closer to the spring 52c, is greater than the thrust of the spring 52c. Thus, the piston 52b moves towards the side closer to the spring 52c, causing both the first connecting port 57 and the third connecting port 59 to communicate with the cylinder body 52a, and the switching valve 52b switches to the open state. This allows hydraulic oil to flow from the first connecting port 57 to the third connecting port 59, and the device is in a state where the hydraulic oil in the first connecting pipe 11 is discharged into the second return pipe 15.

[0051] If the hydraulic pressure in the downstream section 11b of the first connecting pipe is equal to or greater than the first pressure and switches to the open state, and subsequently the hydraulic pressure in the downstream section 11b of the first connecting pipe becomes lower than the first return pressure again, then the switch valve 52 will return to the closed state, that is, the hydraulic oil in the upstream section 11a of the first connecting pipe is not discharged into the third connecting pipe 13.

[0052] Through the operation of the check valve 51 and the switching valve 52, the hydraulic supply device automatically switches between the supply mode and the circulation mode in the following manner.

[0053] like Figure 1 As shown, valve device 5 is in supply mode, in which hydraulic oil from the upstream section 11a of the first connecting pipe is supplied only to the downstream section 11b of the first connecting pipe on the downstream side of valve device 5 until the hydraulic pressure in the downstream section 11b of the first connecting pipe reaches the first pressure after the pump 2 starts to drive for the first time.

[0054] In valve device 5, when the hydraulic pressure in the downstream section 11b of the first connecting pipe reaches or exceeds a first pressure, it switches to circulation mode, in which hydraulic oil in the upstream section 11a of the first connecting pipe is discharged into the second return line 15. Furthermore, if the hydraulic pressure in the downstream section 11b of the first connecting pipe reaches the first pressure and then drops to the first return pressure, valve system 5 switches from circulation mode to supply mode. Then, it remains in supply mode until the hydraulic pressure in the downstream section 11b of the first connecting pipe reaches the first pressure again, in which hydraulic oil from the upstream section 11a of the first connecting pipe is supplied to the downstream section 11b of the first connecting pipe on the downstream side of valve device 5. When the hydraulic pressure in the downstream section 11b of the first connecting pipe reaches the first pressure again, it switches to circulation mode. Thereafter, the switching between circulation mode and supply mode is repeated.

[0055] In the circulation mode, hydraulic oil from pump 2 returns to tank 71 at a lower pressure (with pressure losses corresponding to the pressure losses in each connecting line and valve assembly 5). In other words, in the circulation mode, the delivery pressure (discharge pressure) of pump 2 is reduced. In the circulation mode, check valve 51 closes to separate the upstream section 11a and the downstream section 11b of the first connecting line, thereby preventing backflow. Subsequently, the hydraulic pressure in the downstream section 11b of the first connecting line is maintained for a certain period of time by means of hydraulic oil supplied from accumulator 3.

[0056] In the circulation mode, the delivery pressure of pump 2 is reduced, thus reducing the workload of pump 2. Therefore, the energy consumed by the hydraulic supply device can be reduced.

[0057] Incidentally, in the circulation mode, when the energy of the hydraulic pressure in the downstream section 11b of the first connecting pipe and the accumulator 3 is consumed by the hydraulic system and the hydraulic pressure in the downstream section 11b of the first connecting pipe becomes the first return pressure again, the spring 52c pushes the piston 52b back, thereby returning to the supply mode (see...). Figure 2 The first return pressure is lower than the first pressure. By not stopping pump 2 in the circulation mode, the hydraulic pressure in the downstream section 11b of the first connecting line can be increased immediately after the hydraulic pressure in the downstream section 11b of the first connecting line decreases.

[0058] The hydraulic pressure (i.e., the first return pressure) of the downstream section 11b of the first connecting pipe when returning from the circulation mode to the supply mode can be adjusted by the spring constant of the spring 52c. However, the hysteresis effect between the spring 52c and the piston 52b causes the first return pressure to be less than the first pressure (see...). Figure 2 ).

[0059] The series of operations of valve device 5 (i.e., switching between circulation mode and supply mode) are performed automatically using hydraulic energy. In other words, this embodiment does not require a solenoid valve to switch between circulation mode and supply mode, and therefore does not require wiring or control mechanisms.

[0060] The hydraulic supply device in this embodiment can supply a constant pressure for at least a certain period of time by utilizing the pressure stored in the accumulator 3 and the operating valve device 5, even in the less common case of certain failures in the connected hydraulic system. Specifically, even if certain failures occur in the connected hydraulic system and the pressure in the downstream section 11b of the first connecting line or the second connecting line 12 is in a state of decreasing pressure, the pressure storage in the accumulator 3 and the operation of the valve device 5 can prevent the workload of the pump 2 from being kept at a constantly high level. In addition, problems caused by the temperature rise of the hydraulic oil can be avoided in this way. Furthermore, compared to simply performing on / off control of the pump 2 instead of switching to the circulation mode, frequent operation and stopping of the pump 2 is not required, thereby extending the service life of the pump 2 and reducing pump 2 failures. In addition, when the pressure in the downstream section 11b of the first connecting line drops below the predetermined control pressure, the pressure in the downstream section 11b of the first connecting line can be immediately restored. Furthermore, compared to the case where the motor 21 of pump 2 is driven by an inverter (rather than switched to cyclic mode) and the output of pump 2 is variable, there is no need to repeatedly increase and decrease the output of pump 2. Therefore, when the pressure in the downstream section 11b of the first connecting pipe drops, it has the ability to immediately restore the pressure in the downstream section 11b of the first connecting pipe. In particular, if a fault occurs in the hydraulic system, the rise and fall of the output of pump 2 will be repeated frequently, and even assuming that the drive control of pump 2 may not be able to respond to the pressure drop in the downstream section 11b of the first connecting pipe in a timely manner, the hydraulic supply device in this embodiment can still easily and timely respond to the pressure drop in the downstream section 11b of the first connecting pipe.

[0061] As described above, the pressure sensor 62 and the pressure relief valve 72 can be connected to the first connection line 11.

[0062] The pressure sensor 62 may also be a pressure switch connected to the downstream section 11b of the first connecting pipe. In the hydraulic supply device of this embodiment, based on the pressure detected by the pressure sensor 62, it can be determined whether the hydraulic pressure in the downstream section 11b of the first connecting pipe is sufficient (e.g., whether it is equal to or greater than the first return pressure) to control the operating state of the pump 2.

[0063] For example, based on the pressure detected by the pressure sensor 62, the rotation and stop of the motor 21 can be controlled, thereby controlling the operating state of the pump 2.

[0064] For example, when the hydraulic pressure in the downstream section 11b of the first connecting pipe, detected by pressure sensor 62, becomes equal to or greater than the second pressure (an example of a hydraulic detection process), pressure sensor 62 can be used as a pressure switch to transmit a predetermined signal, thereby stopping the motor 21 of pump 2. In the following text, the state in which the motor 21 of pump 2 is stopped in the hydraulic supply device will be referred to as the stop mode.

[0065] In the stop mode, as in the circulation mode, the check valve 51 is closed to disconnect the upstream section 11a of the first connecting pipe from the downstream section 11b of the first connecting pipe, and the hydraulic pressure in the downstream section 11b of the first connecting pipe is maintained for a certain period of time by means of the accumulator 3.

[0066] After stopping the motor 21 and switching the hydraulic supply device from the circulation mode to the stop mode, if the hydraulic pressure in the downstream section 11b of the first connecting line drops below the second pressure, for example, to a second return pressure (e.g., 10.5 MPa) below the second pressure, the pressure sensor 62 sends a predetermined signal to drive the motor 21 of the pump 2, and then the hydraulic supply device can return to the circulation mode.

[0067] By further equipping the hydraulic supply device with a pressure sensor 62, which functions as a pressure switch, the hydraulic supply device can switch between a supply mode, a circulation mode, and a stop mode. Furthermore, when the hydraulic supply device can switch between these modes, the second pressure can be less than the first pressure. The second return pressure can be less than the first return pressure.

[0068] By setting the first pressure, first return pressure, second pressure, and second return pressure as described above, if the use of the stop mode is preferred over the circulation mode, the pressure sensor 62 can be activated, and the hydraulic supply device can be set to a first operating mode that switches between the supply mode and the stop mode. Furthermore, if there is a malfunction in the hydraulic system, for example, if the use of the circulation mode is preferred over the stop mode, the operation can be switched from the first operating mode to the second operating mode by deactivating the pressure sensor 62 and setting the hydraulic supply device to switch between the supply mode and the circulation mode.

[0069] If the second pressure is less than the first pressure, then the situation where it is desirable to operate in the first operating mode is smaller, and it is possible to avoid switching from the supply mode to the cycle mode before switching from the supply mode to the stop mode.

[0070] In the stop mode, pump 2 stops, thus further reducing the energy consumed by the hydraulic supply device compared to the circulation mode. However, in the first operating mode where the hydraulic supply device uses the stop mode, the operation and stopping of pump 2 need to be repeated frequently, especially when the pressure in the downstream section 11b of the first connecting line or the second connecting line 12 is likely to drop due to some fault in the hydraulic system. Furthermore, if the pressure in the downstream section 11b of the first connecting line drops below the predetermined control pressure due to a fault, the recovery of the pressure in the downstream section 11b of the first connecting line may be delayed. Therefore, if some fault occurs in the hydraulic system and the pressure in the downstream section 11b of the first connecting line or the second connecting line 12 is likely to drop, by setting the hydraulic supply device to the second operating mode, it is possible to avoid maintaining the workload of pump 2 at a constantly high level, thereby avoiding faults caused by the rise in hydraulic oil temperature. Furthermore, if the pressure in the downstream section 11b of the first connecting line drops below the predetermined control pressure, it also allows for immediate recovery of the pressure in the downstream section 11b of the first connecting line. In other words, in the second operating mode, even if the connected hydraulic system has some faults, it can provide more stable and constant hydraulic pressure for a longer period of time than in the first operating mode.

[0071] Therefore, in the event of any failure in the hydraulic system, the second operating mode is more robust than the first operating mode. However, the use of the second operating mode is not limited to situations where certain failures occur in the hydraulic system, but can also be used depending on the characteristics of the hydraulic system (e.g., the form of hydraulic oil consumption).

[0072] The pressure relief valve 72 is a valve mechanism that discharges hydraulic oil from the downstream section 11b of the first connecting line to the second return line 15. The pressure relief valve 72 is normally closed and, when closed, prevents hydraulic oil from being discharged from the downstream section 11b of the first connecting line to the second return line 15. When the hydraulic pressure in the downstream section 11b of the first connecting line reaches a monitoring pressure (e.g., 18 MPa) higher than a first pressure, the pressure relief valve 72 opens to discharge hydraulic oil from the downstream section 11b of the first connecting line to the second return line 15. The operation of this pressure relief valve 72 prevents a potential malfunction caused by the hydraulic pressure in the downstream section 11b of the first connecting line exceeding the monitoring pressure.

[0073] The other components of the hydraulic supply unit will be described below. For example... Figure 1 As shown, the hydraulic supply device may be equipped with other equipment as described below.

[0074] The connecting line 10 may be equipped with a filter 10a. The filter 10a removes foreign matter from the hydraulic oil introduced from the tank 71.

[0075] Filter 11c can be installed in the first connecting line 11. Filter 11c removes foreign matter from the hydraulic oil flowing in the first connecting line 11. Filter 11c can be installed between the valve assembly 5 and the accumulator 3.

[0076] The first return line 14 may have a filter 14a and a check valve 14b bypassing the filter 14a. The check valve 14b can open when a predetermined pressure difference exists between the upstream and downstream sides. The filter 14a removes foreign matter from the hydraulic oil flowing through the first return line 14. If the filter 14a is clogged, the check valve 14b can open to maintain the flow of hydraulic oil in the first return line 14. Furthermore, the first return line 14 may also be equipped with a pressure sensor 61. The pressure sensor 61 may, for example, be a differential pressure switch operating based on the pressure difference between the inside and outside of the first return line 14. For example, if the pressure sensor 61 is installed upstream of the filter 14a, the pressure difference detected by the pressure sensor 61 can be used to determine whether the filter 14a is clogged. If the pressure sensor 61 is a differential pressure switch, for example, when the pressure difference detected by the pressure sensor 61 exceeds a predetermined threshold, the hydraulic supply device can issue a warning based on the signal emitted from the pressure sensor 61 acting as a differential pressure switch.

[0077] The downstream section 11a of the first connecting line and the second return line 15 can also be interconnected via a shut-off valve 81. For example, the shut-off valve 64 can be opened during maintenance or in case of an anomaly.

[0078] For example, pressure gauge 12a can be installed in the second connection line 12 to monitor whether the pressure reducing valve 4 is working properly and whether the hydraulic pressure of the hydraulic oil supplied from the first connection line 11 is sufficient (in this embodiment, whether it is equal to or greater than the second return pressure).

[0079] The second connecting line 12 and the first return line 14 can be interconnected via a shut-off valve 82. For example, the shut-off valve 82 can be opened during maintenance or in the event of a malfunction.

[0080] A cooling device 91 can also be provided to cool the hydraulic oil stored in the pump 2, motor 21, or tank 71. An example of the cooling device 91 is a fan for air cooling. Figure 1 In the case where pump 2, motor 21, and tank 71 are housed within storage chamber 9, cooling air is blown into storage chamber 9 by a fan that serves as a cooling device 91. In this configuration, storage chamber 9 may also be equipped with pressure switches 92 and 93. For example, when the temperature of storage chamber 9 rises above a predetermined cooling start temperature, pressure switch 92 can activate the operation of cooling device 91. Furthermore, when the temperature of storage chamber 9 drops below a predetermined cooling stop temperature, pressure switch 93 can deactivate the operation of cooling device 91.

[0081] In this way, a hydraulic supply device and a hydraulic supply method can be provided.

[0082] Furthermore, as long as no contradiction arises, the structures disclosed in the above embodiments (including other embodiments, the same below) can be combined and applied with the structures disclosed in other embodiments. The embodiments disclosed here are only examples, and the embodiments of the present invention are not limited thereto. The embodiments can be appropriately modified and altered within the scope of the purpose of the present invention.

[0083] Industrial applicability

[0084] This invention applies to hydraulic supply devices and hydraulic supply methods.

[0085] List of reference numerals

[0086] 10: Introduce connecting pipes

[0087] 10a: Filter

[0088] 11: First connecting pipe

[0089] 11a: Upstream section of the first connecting pipe

[0090] 11b: Downstream section of the first connecting pipe

[0091] 11c: Filter

[0092] 12: Second connecting pipe

[0093] 13: Third connecting pipe

[0094] 14: First return pipeline

[0095] 14a: Filter

[0096] 14b: Check valve

[0097] 15: Second return pipeline

[0098] 2: Pump

[0099] 21: Electric motor

[0100] 3: Accumulator

[0101] 4: Pressure reducing valve

[0102] 5: Valve device

[0103] 51: Check valve

[0104] 51a: Valve body

[0105] 51b: Spring

[0106] 51c: Valve seat

[0107] 52: Switch valve

[0108] 52a: Cylinder block section

[0109] 52b: Piston

[0110] 52c: Spring

[0111] 53: Pressure transmission connection pipeline

[0112] 57: First connection port

[0113] 58: Second connection port

[0114] 59: Third connection port

[0115] 61: Pressure sensor

[0116] 62: Pressure sensor

[0117] 64: Gate valve

[0118] 71: Jar

[0119] 72: Pressure relief valve

[0120] 81: Gate valve

[0121] 82: Gate valve

[0122] 9: Storage room

[0123] 91: Cooling device

[0124] 92: Pressure switch

[0125] 93: Pressure switch

Claims

1. A hydraulic supply device, comprising: First connecting pipe; Pump, which delivers hydraulic oil to the first connecting pipeline; The second connecting pipeline is used to supply hydraulic oil from the first connecting pipeline to the second connecting pipeline; The third connecting pipe is used to return the hydraulic oil from the second connecting pipe to the third connecting pipe; An accumulator, connected to the first connecting line, to store the hydraulic oil delivered from the pump; A pressure reducing valve reduces the pressure of the hydraulic oil introduced from the first connecting line, and then supplies the hydraulic oil to the second connecting line; and a valve device that discharges the hydraulic oil from the first connecting line to the third connecting line, wherein The second connecting pipe is connected to the first connecting pipe only through the pressure reducing valve. Furthermore, when the pressure of the hydraulic oil in the first connecting pipeline is equal to or greater than the first pressure, the valve device switches from a state of not discharging the hydraulic oil in the first connecting pipeline to the third connecting pipeline to a state of discharging the hydraulic oil in the first connecting pipeline to the third connecting pipeline. A pressure sensor is also installed in the first connecting pipeline. When the pressure of the hydraulic oil in the first connecting pipeline detected by the pressure sensor exceeds a second pressure, the pump stops. The first operating mode can be switched to a second operating mode. The first operating mode switches between a supply mode in which the hydraulic oil in the first connecting pipeline is not discharged to the third connecting pipeline and a stop mode in which the pump is stopped. The second operating mode switches between the supply mode and a circulation mode in which the hydraulic oil in the first connecting pipeline is discharged to the third connecting pipeline. In the second operating mode, the switching between the supply mode and the circulation mode is automatically performed by the valve device using hydraulic energy.

2. The hydraulic supply device according to claim 1, wherein, The second pressure is less than the first pressure.

3. A hydraulic supply method, comprising: The hydraulic oil delivery process involves delivering hydraulic oil to the first connecting pipeline. The return process involves returning the hydraulic oil from the second connecting line to the third connecting line. During the pressure storage process, the hydraulic oil supplied to the first connecting pipeline is stored in the accumulator. The pressure-reducing supply process involves introducing hydraulic oil into the first connecting pipeline, reducing the pressure of the hydraulic oil, and then supplying the hydraulic oil to the second connecting pipeline. and a discharge process, wherein the hydraulic oil is discharged from the first connecting pipe to the third connecting pipe, wherein The pressure-reducing supply process only supplies the hydraulic oil, which has been introduced into and depressurized from the first connecting pipeline, to the second connecting pipeline. Furthermore, if the pressure of the hydraulic oil in the first connecting pipeline is equal to or greater than the first pressure, the discharge process switches from a state where the hydraulic oil in the first connecting pipeline is not discharged to the third connecting pipeline to a state where the hydraulic oil in the first connecting pipeline is discharged to the third connecting pipeline. The method further includes a hydraulic detection process, which detects the pressure of the hydraulic oil in the first connecting pipeline. If the pressure of the hydraulic oil in the first connecting pipeline exceeds a second pressure, the hydraulic detection process stops supplying the hydraulic oil to the first connecting pipeline. The first operating mode can switch to a second operating mode. The first operating mode switches between a supply mode in which hydraulic oil is not discharged from the first connecting pipe to the third connecting pipe and a stop mode in which the supply of hydraulic oil to the first connecting pipe is stopped. The second operating mode switches between a supply mode and a circulation mode in which hydraulic oil is discharged from the first connecting pipe to the third connecting pipe. In the second operating mode, the switching between the supply mode and the circulation mode is automatically performed using hydraulic energy.

4. The hydraulic supply method according to claim 3, wherein the second pressure is less than the first pressure.

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