Hydraulic system, hydraulic elevator unit, hydraulic system control program, and valve mechanism

Abstract

To provide a hydraulic elevator unit high in energy efficiency and a valve mechanism applicable to the hydraulic elevator unit.SOLUTION: A hydraulic elevator unit 2 comprises: a cage K that can accommodate a human or an article; a hydraulic cylinder unit 20; a working fluid tank unit 30 that stores a working fluid; a working fluid path forming unit 40 that forms a working fluid path from the working fluid tank unit 30 to the hydraulic cylinder unit 20; a motor 90 provided in the working fluid path forming unit 40; an inverter 95 connected to the motor 90; and a control mechanism 10 for controlling each unit.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a hydraulic system, a hydraulic elevator unit, a control program for a hydraulic system, and a valve mechanism.

Background Art

[0002] A hydraulic elevator unit drives a car chamber up and down by a hydraulic cylinder, and has a larger load capacity than a rope-type elevator and is suitable for transporting important goods (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] On the other hand, from the viewpoint of protecting the global environment and preventing global warming, the demand for energy conservation for electrical equipment and industrial machinery is increasing. This demand is no exception for hydraulic elevator units.

[0005] In a conventional hydraulic elevator unit, the speed adjustment when lowering the car chamber is performed based on the flow rate adjustment of the hydraulic oil using a throttle valve or the like. However, in such a flow rate adjustment method, frictional heat is generated in the hydraulic oil, so that most of the kinetic energy of the car chamber becomes frictional heat. Therefore, as a hydraulic elevator unit, the energy efficiency cannot be said to be sufficient.

[0006] In view of such circumstances, the present invention aims to provide a hydraulic system, a hydraulic elevator unit with good energy efficiency, a control program for a hydraulic system applicable thereto, and a valve mechanism.

Means for Solving the Problems

[0007] The present invention relates to a hydraulic system comprising a hydraulic actuator having a piston that rises with the inflow of hydraulic oil and falls with the outflow of the hydraulic oil, an input unit to which a lowering command for the piston is input, a pump that adjusts the amount of the hydraulic oil in the hydraulic actuator for positioning the piston, a motor connected to the pump, a valve mechanism that controls the flow rate of the hydraulic oil between the hydraulic actuator and the pump, and a valve control unit that controls the valve mechanism based on the lowering command. When a lowering sequence in which the piston descends is defined as an acceleration mode in which the descending speed of the piston gradually increases, a deceleration mode in which the descending speed gradually decreases, and a constant speed mode that is between the acceleration mode and the deceleration mode and in which the descending speed is a target value, the valve control unit controls the valve mechanism based on the lowering command so that the frequency of the regenerative power generated from the motor in the constant speed mode becomes a target value, and the flow rate of the hydraulic oil passing through the pump in the constant speed mode is set corresponding to the target value of the frequency of the regenerative power generated from the motor.

[0008] The motor is preferably connected to an inverter, the inverter is connected to a commercial power supply, and the target value is preferably the frequency of the commercial power supply input to the inverter. Further, it is preferable to include a commercial power supply management unit that reads the frequency of the commercial power supply input to the inverter, a regenerative power management unit that reads the frequency of the regenerative power generated from the motor, and a frequency determination unit that determines whether or not the difference between the frequency of the regenerative power and the frequency of the commercial power supply is within an allowable range. Furthermore, a phase difference determination unit that determines whether or not the phase difference between the frequency of the commercial power supply and the frequency of the regenerative power is within an allowable range is provided. The commercial power supply management unit reads the phase of the commercial power supply, the regenerative power management unit reads the phase of the regenerative power, and the valve control unit preferably controls the valve mechanism so as to cancel the phase difference between the regenerative power and the commercial power in the constant speed mode.

[0009] Preferably, the valve control unit controls the valve mechanism in the acceleration mode so as to cancel out the phase difference between the regenerative power and the commercial power in the constant speed mode. Further, it is preferable that the valve control unit cancels out the phase difference by adjusting the start timing of the acceleration mode. Furthermore, it is preferable that the valve control unit cancels out the phase difference by adjusting the start timing of the constant speed mode.

[0010] The hydraulic elevator unit of the present invention is characterized by including the above-described hydraulic system and a car chamber provided on the piston and moving in the vertical direction by the hydraulic system.

[0011] The valve mechanism includes a valve block, a first liquid passage port formed in the valve block, a second liquid passage port formed in the valve block, a communication passage communicating the first liquid passage port and the second liquid passage port, a main valve body disposed in the communication passage, and a sub-valve body provided on the valve block. The sub-valve body is switchable between a protruding state protruding from the wall surface of the communication passage and a protruding retracted state retracted from the protruding state. The main valve body is switchable between a contact state in contact with the sub-valve body and a contact retracted state retracted from the contact state. The communication passage is switchable between an open state in which the main valve body is in the contact retracted state, a slightly open state in which the sub-valve body is in the protruding state and the main valve body is in the contact state, and a closed state in which the sub-valve body is in the protruding retracted state and the main valve body is in the contact state. In the constant speed mode, the communication passage is in the open state. In the deceleration mode, the communication passage is in the slightly open state. It is preferable that the communication passage is in the closed state when the car chamber stops.

[0012] The present invention is a control program for a hydraulic system for causing a computer to execute an input step of receiving an input of a lowering command, a lowering command storage step of storing the lowering command in a storage device, and a valve control step of controlling the valve mechanism based on the lowering command. The hydraulic system includes a hydraulic actuator having a piston that rises by the inflow of hydraulic oil and descends by the outflow of the hydraulic oil, a pump that adjusts the amount of the hydraulic oil in the hydraulic actuator for positioning the piston, a motor connected to the pump, an inverter connected to the motor and also connected to a commercial power source, a valve mechanism that controls the flow rate of the hydraulic oil between the hydraulic actuator and the pump, and a valve control unit that controls the valve mechanism based on the lowering command. When a lowering sequence in which the piston descends is defined as an acceleration mode in which the descending speed of the piston gradually increases, a deceleration mode in which the descending speed gradually decreases, and a constant speed mode in which the descending speed is between the acceleration mode and the deceleration mode and is a target value, in the valve control step, based on the lowering command, the valve mechanism is controlled so that the frequency of the regenerative power generated from the motor in the constant speed mode becomes a target value, and the flow rate of the hydraulic oil passing through the pump in the constant speed mode corresponds to the target value of the frequency of the regenerative power generated from the motor, and the target value is the frequency of the commercial power source input to the inverter.

[0013] In the valve control step, it is preferable to read the frequency of the commercial power source input to the inverter, read the frequency of the regenerative power generated from the motor, and determine whether the difference between the frequency of the regenerative power and the frequency of the commercial power source is within an allowable range. Further, in the valve control step, the commercial power management unit reads the phase of the commercial power source, the regenerative power management unit reads the phase of the regenerative power, determines whether the phase difference between the frequency of the commercial power source and the frequency of the regenerative power is within an allowable range, and preferably controls the valve mechanism so as to cancel the phase difference between the regenerative power and the commercial power in the constant speed mode.

[0014] The present invention is a valve mechanism for controlling the flow rate of hydraulic oil in a hydraulic elevator system, comprising a valve block, a first liquid passage port formed in the valve block, a second liquid passage port formed in the valve block, a communication passage communicating the first liquid passage port and the second liquid passage port, a main valve body disposed in the communication passage, and a sub-valve body provided in the valve block. The sub-valve body is switchable between a protruding state protruding from the wall surface of the communication passage and a protruding retracted state retracted from the protruding state. The main valve body is switchable between a contact state in contact with the sub-valve body and a contact retracted state retracted from the contact state. The communication passage is switchable between an open state in which the main valve body is in the contact retracted state, a slightly open state in which the sub-valve body is in the protruding state and the main valve body is in the contact state, and a closed state in which the sub-valve body is in the protruding retracted state and the main valve body is in the contact state. In the constant speed mode, the communication passage is in the open state. In the deceleration mode, the communication passage is in the slightly open state. When the car chamber stops, the communication passage is in the closed state.

Effects of the Invention

[0015] According to the present invention, it is possible to provide a hydraulic system with good energy efficiency, a hydraulic elevator unit, a control program for a hydraulic system applicable thereto, and a valve mechanism.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 5C

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

DETAILED DESCRIPTION OF THE INVENTION

[0017] As shown in FIG. 1, the hydraulic elevator unit 2 includes a car body K capable of accommodating people and objects, a switch SW for operating the car body K, a hydraulic cylinder unit 20, a hydraulic oil tank unit 30 for accommodating hydraulic oil, a hydraulic oil path forming unit 40 for forming a path of hydraulic oil from the hydraulic oil tank unit 30 to the hydraulic cylinder unit 20, a motor 90 provided in the hydraulic oil path forming unit 40, an inverter 95 connected to the motor 90, and a control mechanism 10 for controlling each part.

[0018] The hydraulic cylinder unit 20 includes a cylinder 20C into which hydraulic oil can flow, and a piston 20P provided so as to be able to move forward and backward with respect to the cylinder 20C. When hydraulic oil flows into the cylinder 20C, the piston 20P rises, and when hydraulic oil flows out of the cylinder 20C, the piston 20P descends. A car body K is provided at the upper end of the piston 20P. Therefore, the car body K rises or falls due to the inflow or outflow of hydraulic oil in the hydraulic cylinder unit 20.

[0019] The hydraulic oil tank unit 30 includes a tank body 31 for accommodating hydraulic oil, a temperature sensor 32 for detecting the temperature of the hydraulic oil accommodated in the tank body 31, and a temperature control unit 33 for adjusting the temperature of the hydraulic oil accommodated in the tank body 31 to be within a predetermined range. As the temperature control unit 33, an oil cooler for cooling the hydraulic oil by electric power and a cooling fan driven by electric power for cooling the hydraulic oil may be provided.

[0020] The hydraulic fluid path forming unit 40 includes a valve mechanism 50 positioned between the hydraulic fluid tank unit 30 and the hydraulic cylinder unit 20, a pump 43 positioned between the hydraulic fluid tank unit 30 and the valve mechanism 50, a cylinder pipe 44 connecting the valve mechanism 50 and the hydraulic cylinder unit 20, an interlock valve 45 provided in the cylinder pipe 44, a direct pipe 46A extending from the valve mechanism 50 to the hydraulic fluid tank unit 30, and a bypass pipe 46B extending from the valve mechanism 50 to the hydraulic fluid tank unit 30 via the pump 43.

[0021] The pump 43 can rotate forward and backward. When the pump 43 rotates forward, the hydraulic fluid flows from the hydraulic fluid tank unit 30 toward the valve mechanism 50. When the hydraulic fluid flows from the valve mechanism 50 toward the hydraulic fluid tank unit 30, the kinetic energy of the hydraulic fluid is used for the reverse rotation of the pump 43.

[0022] The motor 90 can rotate forward and backward. When the motor 90 rotates forward by the supply of electric power, the pump 43 rotates forward. When the pump 43 rotates backward, the motor 90 also rotates backward. As a result, the motor 90 generates regenerative electric power.

[0023] The inverter 95 is connected to a commercial power source. Therefore, the inverter 95 can supply the electric power from the commercial power source to the motor 90 and rotate the motor 90 forward. Furthermore, the inverter 95 can supply the electric power generated by the reverse rotation of the motor 90 from the motor 90 to the commercial power source.

[0024] The valve mechanism 50 includes a main valve 51 (flow rate control valve), a relief valve 52, and a connection flow path 53 connecting the main valve 51 and the relief valve 52.

[0025] As shown in Fig. 2, the main valve 51 includes a valve block 51B, a first liquid passage port 51C formed in the valve block 51B and connected to the cylinder pipe 44, a second liquid passage port 51D formed in the valve block 51B and connected to the connecting flow path 53, a communication passage 51E that communicates the first liquid passage port 51C and the second liquid passage port 51D, a main valve body 51M accommodated in the communication passage 51E, a sub-valve body 51S formed in the valve block 51B, a main valve body solenoid 51L that drives the main valve body 51M, and a sub-valve body solenoid 51R that drives the sub-valve body 51S.

[0026] The valve block 51B is formed in a rectangular parallelepiped shape. Hereinafter, for convenience of explanation, the direction extending horizontally is defined as the X direction, the direction extending horizontally and orthogonal to the X direction is defined as the Y direction, and the direction orthogonal to the X direction and the Y direction is defined as the Z direction. Among the sides forming the valve block 51B, an arbitrary side is defined as the side extending in the X direction.

[0027] As shown in Fig. 2(A), in the valve block 51B, the first liquid passage port 51C is formed on one surface (the upper surface in the Z direction), the second liquid passage port 51D is formed on the opposite surface (the lower surface in the Z direction), and a communication passage 51E that communicates the first liquid passage port 51C and the second liquid passage port 51D is formed inside the valve block 51B.

[0028] The communication passage 51E extends in the X direction and includes a main valve body accommodation space 51EM in which the main valve body 51M is movable in the X direction and a sub-valve body accommodation space 51ES in which the sub-valve body 51S is movable in the X direction.

[0029] The main valve body accommodation space 51EM is formed in a cylindrical shape and extends in the X direction. In the main valve body accommodation space 51EM, a main large-diameter space portion 51EM1 is formed on one side in the X direction (the right side of the paper surface), a main small-diameter space portion 51EM2 is formed on the other side in the X direction (the left side of the paper surface), and a reduced-diameter space portion 51EM3 is formed between the main large-diameter space portion 51EM1 and the main small-diameter space portion 51EM2.

[0030] As shown in FIG. 2(B), the main valve body 51M is formed as a cylindrical body and extends in the X direction. In the main valve body 51M, a large-diameter portion 51M1 of the main valve body is formed on one side in the X direction, a small-diameter portion 51M2 of the main valve body is formed on the other side in the X direction, and a reduced-diameter portion 51M3 of the main valve body is formed between the large-diameter portion 51M1 and the small-diameter portion 51M2 of the main valve body.

[0031] As shown in FIG. 3, the large-diameter portion 51M1 of the main valve body is movable in the X direction in the main large-diameter space portion 51EM1. The small-diameter portion 51M2 of the main valve body is movable in the X direction in the main small-diameter space portion 51EM2. Similarly, the reduced-diameter portion 51M3 of the main valve body is movable in the X direction in the reduced-diameter space portion 51EM3.

[0032] In this way, the main valve body 51M can be switched between a contact state (FIG. 3(A)) in which the other end portion 51M2X in the X direction of the small-diameter portion 51M2 of the main valve body contacts the inner wall surface 51EMX of the other end portion in the X direction of the main small-diameter space portion 51EM2 and a contact-retracted state (FIG. 3(B)) separated from the inner wall surface 51EMX.

[0033] The main valve body solenoid 51L is arranged to be expandable and contractible in the X direction. One end portion in the X direction contacts the valve block 51B, and the other end portion in the X direction is exposed in the main large-diameter space portion 51EM1. When the main valve body solenoid 51L is in an energized state, the main valve body 51M is in a contact-retracted state (FIG. 3(B)). When the main valve body solenoid 51L is in a non-energized state, the main valve body 51M is biased by a coil spring (not shown) to be in a contact state (FIG. 3(A)). This coil spring is arranged to be expandable and contractible in the X direction within the valve block 51B. One end portion in the X direction contacts the valve block 51B, and the other end portion in the X direction contacts the main valve body 51M.

[0034] Returning to Fig. 2(A), the sub-valve body accommodation space 51ES is formed in a cylindrical shape and extends in the X direction. On one side in the X direction of the sub-valve body accommodation space 51ES, a sub-small diameter space portion 51ES1 is formed, and on the other side in the X direction, a sub-large diameter space portion 51ES2 is formed. Also, the diameter of the sub-small diameter space portion 51ES1 is smaller than the diameter of the main small diameter space portion 51EM2. One side in the X direction of the sub-small diameter space portion 51ES1 opens to the inner wall surface 51EMX at the other end in the X direction of the main small diameter space portion 51EM2.

[0035] As shown in Fig. 2(B), the sub-valve body 51S is formed in a cylindrical shape and extends in the X direction. In the sub-valve body 51S, a sub-valve body small diameter portion 51S1 is formed on one side in the X direction, and a sub-valve body large diameter portion 51S2 is formed on the other side in the X direction. As shown in Fig. 4, the sub-valve body small diameter portion 51S1 is movably accommodated in the X direction in the sub-small diameter space portion 51ES1, and the sub-valve body large diameter portion 51S2 is movably accommodated in the X direction in the sub-large diameter space portion 51ES2.

[0036] Since the outer diameter of the sub-valve body large diameter portion 51S2 is smaller than the outer diameter of the sub-valve body small diameter portion 51S1, the sub-valve body large diameter portion 51S2 cannot enter the sub-small diameter space portion 51ES1. Therefore, the sub-valve body small diameter portion 51S1 can reciprocate in the X direction by the moving length of the sub-valve body large diameter portion 51S2 in the sub-large diameter space portion 51ES2.

[0037] The sub-valve body 51S can be switched between a protruding state where the sub-valve body small diameter portion 51S1 protrudes from the inner wall surface 51EMX (Fig. 4(A)) and a protruding and retracted state where the sub-valve body small diameter portion 51S1 retracts from the protruding state (Fig. 4(B)). In the protruding and retracted state, the end face on one side in the X direction of the sub-valve body small diameter portion 51S1 is flush with the inner wall surface 51EMX and also serves as a part of the inner wall surface 51EMX.

[0038] The pilot valve body solenoid 51R is arranged to be expandable and contractible in the X direction. The other end in the X direction abuts against the valve block 51B, and one end in the X direction is exposed to the auxiliary large-diameter space portion 51ES2. When the pilot valve body solenoid 51R is in an energized state, the pilot valve body 51S is in a protruding state. When the pilot valve body solenoid 51R is de-energized, the pilot valve body 51S is biased by a coil spring (not shown) to be in a protruding and retracted state. This coil spring is arranged to be expandable and contractible in the X direction within the valve block 51B. The other end in the X direction abuts against the valve block 51B, and the other end in the X direction abuts against the pilot valve body 51S.

[0039] As shown in FIG. 5A, an operating oil flow space R that communicates the first liquid passage port 51C and the second liquid passage port 51D is formed between the main valve body accommodation space 51EM and the main valve body 51M. Regardless of the state of the pilot valve body 51S, when the main valve body solenoid 51L is in a de-energized state, the main valve body 51M is in a contacting and retracted state (FIG. 3(B)), so the operating oil flow space R is in an open state (FIG. 5A).

[0040] When the pilot valve body solenoid 51R and the main valve body solenoid 51L are in an energized state, when the pilot valve body 51S is in a protruding and retracted state (FIG. 4(B)) and the main valve body 51M is in a contacting state (FIG. 3(A)), the operating oil flow space R is in a closed state (FIG. 5C).

[0041] When the pilot valve body solenoid 51R is in a de-energized state and the main valve body solenoid 51L is in an energized state, the pilot valve body 51S is in a protruding state (FIG. 4(B)). On the other hand, as a result of the main valve body 51M abutting against the pilot valve body 51S protruding from the inner wall surface 51EMX, the operating oil flow space does not reach an open state (FIG. 5A) and becomes an intermediate state (slightly open state) between the open state and the closed state (FIG. 5B).

[0042] Returning to FIG. 1, the relief valve 52 connects either one of the direct piping 46A and the bypass piping 46B to the second fluid port 51D (FIG. 2) of the main valve 51 and blocks the other. When the relief valve 52 is energized, it connects to the second fluid port 51D via the bypass piping 46B while blocking the direct piping 46A. When the relief valve 52 is de-energized, it connects to the second fluid port 51D via the direct piping 46A while blocking the bypass piping 46B.

[0043] As shown in FIG. 6, the control mechanism 10 includes a CPU 11, a RAM 12, a ROM 13, an external storage device 14, an input device 15, an output device 16, an input / output interface 18, and a bus 19.

[0044] The CPU 11 is a so-called central processing unit, and various programs are executed to realize various services of the management server 10. The RAM 12 is a so-called RAM (Random Access Memory) and is used as a working area for the CPU 11. The ROM 13 is a so-called ROM (Read Only Memory) and stores the basic OS and various programs (for example, a control program for a hydraulic system) executed by the CPU 11.

[0045] The external storage device 14 stores calculation results of various programs and the like, and includes a built-in storage device (for example, a hard disk drive or a solid state drive), a removable storage device (for example, a memory card, etc.). Note that the external storage device 14 may be connected via a communication line like a NAS (Network Attached Storage).

[0046] The input device 15 is an input key keyboard, a mouse, a barcode reader, or a two-dimensional code reader, and inputs various information. The output device 16 is a display or the like, and displays various operating states.

[0047] The input / output interface 18 (which also serves as an input device and an output device) enables communication on the communication line. The bus 19 is a wiring that integrally connects the CPU 11, RAM 12, ROM 13, input device 15, output device 16, input / output interface 18, etc. to perform communication.

[0048] When the basic OS and various programs stored in the ROM 13 are executed by the CPU 11, as shown in FIG. 7, the CPU 11 of the control mechanism 10 functions as an instruction input unit 11CM, a valve control unit 11BB, a pump control unit 11PM, a motor control unit 11MT, a regenerative power management unit 11WA, a commercial power management unit 11WB, a frequency determination unit 11JF, a phase difference determination unit 11JP, and a control unit 11CT that controls each unit.

[0049] The instruction input unit 11CM receives a descent instruction or an ascent instruction for the car chamber K. The descent instruction or ascent instruction for the car chamber K is output by operating the switch SW (FIG. 1).

[0050] The pump control unit 11PM controls the pump 43 according to a descent instruction or an ascent instruction for the car chamber K. The motor control unit 11MT controls the motor 90 according to a descent instruction or an ascent instruction for the car chamber K.

[0051] The regenerative power management unit 11WA reads the frequency and phase of the regenerative power of the motor 90. The commercial power management unit 11WB reads the frequency and phase of the commercial power input to the inverter 95.

[0052] The frequency determination unit 11JF determines whether the difference between the frequency of the commercial power input to the inverter 95 and the frequency of the regenerative power of the motor 90 is within the allowable range. The phase difference determination unit 11JP determines whether the difference between the phase of the commercial power input to the inverter 95 and the phase of the regenerative power of the motor 90 is within the allowable range.

[0053] The valve control unit 11BB controls the valve unit 50 in accordance with the lowering command or the raising command of the car cabin K. Further, the valve control unit 11BB controls the valve unit 50 and the like so that the frequency of the regenerative power in the motor 90 and its phase difference become predetermined values based on the determination results in the frequency determination unit 11JF and the phase difference determination unit 11JP.

[0054] Next, the operation of the hydraulic elevator unit 2 will be described.

[0055] When the car cabin K is in a stopped state, since the sub-valve body 51S is in the protruding and retracted state (FIG. 4(B)) and the main valve body 51M is in the contact state (FIG. 3(A)), the hydraulic oil flow space is in a closed state (FIG. 5C). The relief valve 52 connects to the main valve 51 on one hand to the direct piping 46A and shuts off the bypass piping 46B.

[0056] The switch SW (FIG. 1) is operated, and a raising command for the car cabin K is output from the switch SW. When the raising command is input to the command input unit 11CM, the control mechanism 10 controls each part so as to raise the car cabin K by a predetermined height in accordance with this raising command.

[0057] When the car cabin K is raised at the first speed, under the control of the control unit 11CT, the inverter 95 supplies power from the commercial power supply to the motor 90 and rotates the motor 90 forward. The motor control unit 11MT rotates the motor 90 forward, causing the pump 43 to rotate forward. When the pump 43 rotates forward, the hydraulic oil flows from the hydraulic oil tank unit 30 toward the valve mechanism 50. When a predetermined amount of hydraulic oil is supplied to the valve mechanism 50, under the control of the valve control unit 11BB, the relief valve 52 connects the direct pipe 46A to the main valve 51 while blocking the bypass pipe 46B. Further, the valve control unit 11BB protrudes the sub-valve body 51S (Fig. 4(A)) and places the main valve body 51M in the contact-retracted state (Fig. 3(B)). As a result, the hydraulic oil flow space becomes the open state (Fig. 5A). Since the forward rotation of the pump 43 continues, a predetermined amount of hydraulic oil flows from the hydraulic oil tank unit 30 toward the hydraulic cylinder unit 20. Thereby, the car cabin K moves upward by a predetermined amount.

[0058] When the car cabin K is raised at a speed slower than the first speed (second speed), under the control of the valve control unit 11BB, when the sub-valve body 51S is in the protruding state (Fig. 4(A)) and the main valve body 51M is in the contact state (Fig. 3(A)), as a result of the main valve body 51M contacting the sub-valve body 51S protruding from the inner wall surface 51EMX, the hydraulic oil flow space R does not reach the open state (Fig. 5A) and becomes an intermediate state between the open state and the closed state (slightly open state) (Fig. 5B). Although the forward rotation of the pump 43 continues, since the hydraulic oil flow space R is in the slightly open state, the flow rate of the hydraulic oil passing through the main valve 51 becomes small. Therefore, the car cabin K can be raised at a speed slower than the first speed (second speed).

[0059] When the car cabin K is to be stopped, under the control of the valve control unit 11BB, the sub-valve body 51S is in the protruding and retracted state (Fig. 4(A)) and the main valve body 51M is in the contact state (Fig. 3(A)). As a result, the hydraulic oil flow space becomes the closed state (Fig. 5(C)). Then, the forward rotation of the pump 43 stops. Thereafter, it is preferable that the relief valve 52 connects the main valve 51 to the direct pipe 46A by the valve control unit 11BB.

[0060] To lower the car body K in the stopped state at a high speed (first speed), control is performed as follows. When the car body K in the stopped state is in the stopped state, under the control of the valve control unit 11BB, the sub-valve body 51S is in the protruding and retracted state (FIG. 4(A)) and the main valve body 51M is in the contact state (FIG. 3(A)), so the hydraulic oil flow space R is in the closed state (FIG. 5C).

[0061] The switch SW (FIG. 1) is operated, and a lowering command for the car body K is output from the switch SW. When the lowering command is input to the command input unit 11CM, the control mechanism 10 controls each part to lower the car body K by a predetermined height in accordance with this lowering command.

[0062] First, under the control of the valve control unit 11BB, the relief valve 52 connects the main valve 51 and the via pipe 46B. Under the control of the control unit 11CT, the inverter 95 supplies power from the commercial power supply to the motor 90 and rotates the motor 90 forward. By rotating the motor 90 forward, the pump 43 rotates forward. By the forward rotation of the pump 43, hydraulic oil flows from the hydraulic oil tank unit 30 toward the valve mechanism 50. When the hydraulic oil pressures on the upstream side and the downstream side of the valve mechanism 50 become equal, the valve control unit 11BB makes the sub-valve body 51S protrude (FIG. 4(A)) and makes the main valve body 51M contact and retract (FIG. 3(B)). As a result, the hydraulic oil flow space becomes the open state (FIG. 5A). Therefore, the hydraulic oil on the side of the hydraulic cylinder unit 20 rather than the pump 43 flows through the pump 43 to the hydraulic oil tank unit 30 by gravity. As a result, the pump 43 rotates reversely. By the reverse rotation of the pump 43, the motor 90 also rotates reversely and generates electric power. Further, the inverter 95 supplies the electric power generated by the reverse rotation of the motor 90 from the motor 90 to the commercial power supply.

[0063] When the car cage K is lowered at a speed slower than the first speed (second speed), under the control of the valve control unit 11BB, the sub-valve body 51S is in the protruding and retracted state (FIG. 4(B)), and the main valve body 51M is in the contact state (FIG. 3(A)). As a result, the hydraulic oil flow space R does not reach the open state (FIG. 5A), but becomes an intermediate state between the open state and the closed state (slightly open state) (FIG. 5B). Since the flow rate of the hydraulic oil passing through the main valve 51 decreases, the car cage K can be lowered at a speed slower than the first speed (second speed). Also at this time, similar to when the car cage K is lowered at a fast speed (first speed), due to the reverse rotation of the pump 43, the motor 90 also rotates in the reverse direction to generate regenerative power. Further, the inverter 95 supplies the regenerative power generated by the reverse rotation of the motor 90 from the motor 90 to the commercial power supply.

[0064] When the car cage K is brought to a stop state, under the control of the valve control unit 11BB, the sub-valve body 51S is in the protruding and retracted state (FIG. 4(A)) and the main valve body 51M is in the contact state (FIG. 3(A)). As a result, the hydraulic oil flow space R becomes the closed state (FIG. 5C). Thereafter, it is preferable that the relief valve 52 connects to the main valve 51 to the direct pipe 46A and shuts off the via pipe 46B.

[0065] Next, in order for the inverter 95 to supply the regenerative power generated by the motor 90 when the car cage K descends to the commercial power supply, it is preferable that the difference between the frequency of the regenerative power and the frequency of the commercial power supply is within the allowable range, and the phase difference between the regenerative power and the commercial power supply is within the allowable range.

[0066] Here, if the lowering sequence of the car cage K is defined as an acceleration mode in which the lowering speed of the car cage K gradually increases, a deceleration mode in which the lowering speed of the car cage K gradually decreases, and a constant speed mode that is between the acceleration mode and the deceleration mode and in which the lowering speed is the target value (FIG. 8), it is desirable for the control unit 10 to perform the following control.

[0067] When a lowering command is input to the command input unit 11CM, the regenerative power management unit 11WA reads the frequency and phase of the regenerative power of the motor 90, and the commercial power supply management unit 11WB reads the frequency and phase of the commercial power supply input to the inverter 95.

[0068] Next, the control unit 11CT calculates the frequency difference and phase difference between the regenerative power of the motor 90 and the commercial power supply. Then, the control unit 11CT determines the outflow amount profile of the hydraulic oil in the acceleration mode so that the frequency difference between the regenerative power of the motor 90 and the commercial power supply in the constant speed mode is within a predetermined range (for example, within ±1% of the target value). Along with the determination of the outflow amount profile of the hydraulic oil in the acceleration mode, the speed profile of the car body in the acceleration mode (Fig. 8(A)) and the frequency profile of the regenerative power are determined (Fig. 8(B)).

[0069] After that, based on the frequency profile of the regenerative power, the control unit 11CT delays the start timing of the acceleration mode by Δt1 so that the phase difference θ between the regenerative power of the motor 90 and the commercial power supply at the start of the constant speed mode becomes smaller (Fig. 9).

[0070] As a result, the frequency difference and phase difference between the regenerative power and the commercial power supply in the constant speed mode are within a predetermined range, so that the regenerative power generated in the constant speed mode can be supplied to the commercial power supply via the inverter 95.

[0071] Note that, based on the frequency profile of the regenerative power, the start timing of the acceleration mode may be advanced so that the phase difference θ between the regenerative power of the motor 90 and the commercial power supply at the start of the constant speed mode becomes smaller.

[0072] Note that, instead of calculating the frequency difference between the commercial power supply input to the inverter 95 and the regenerative power of the motor 90, the commercial power supply management unit 11WB may calculate the frequency difference between the target value stored in the external storage device 14 and the regenerative power of the motor 90. The target value of the frequency of the regenerative power may be 50 Hz in eastern Japan and 60 Hz in western Japan.

[0073] In addition, the speed profile of the cage K in the acceleration mode and the deceleration mode preferably has a gentle change in consideration of the riding comfort.

[0074] In the above embodiment, the control unit 11CT determines the start timing of the acceleration mode based on the frequency profile of the regenerative power so that the regenerative power of the motor 90 and the phase difference θ of the commercial power supply at the start point of the constant speed mode are reduced. However, the present invention is not limited to this, and the required time of the acceleration mode may be adjusted so that the regenerative power of the motor 90 and the phase difference θ of the commercial power supply at the start point of the constant speed mode are reduced. Here, in FIG. 10, the required time of the acceleration mode is made longer by Δt2. In addition, the required time of the acceleration mode may be shortened so that the regenerative power of the motor 90 and the phase difference θ of the commercial power supply at the start point of the constant speed mode are reduced. Further, both the start timing of the acceleration mode and the required time of the acceleration mode may be adjusted.

[0075] In the conventional method, when the cage K is lowered, since the pump 43 is not connected to the motor 90, the falling energy of the hydraulic oil has become thermal energy due to the friction with the pump 43. When the cage K is lowered at the first speed or the second speed, the above hydraulic elevator unit 2 utilizes the falling energy of the hydraulic oil to generate power by the motor 90, leading to energy saving.

[0076] In addition, in the conventional method, the friction with the pump 43 promotes the high temperature of the hydraulic oil during the operation of the system. In order to suppress this, in the conventional method, it is necessary to separately install and operate the temperature control unit 33. However, according to the present invention, the operation amount of the temperature control unit 33 can be reduced or the temperature control unit 33 can be omitted.

[0077] In addition, the friction and high temperature of the hydraulic oil cause the denaturation of additives (viscosity modifiers, flame retardants, etc.) contained in the hydraulic oil. Therefore, according to the present invention, it can also contribute to the shortening of the service life of the hydraulic oil.

[0078] In addition, if an attempt is made to decelerate the car body K at the time of landing by using an inverter, not only will it become difficult to finely adjust the position and speed of the car body, but the control will also tend to increase the energy consumption. In the hydraulic elevator unit 2, since the main valve body 51M and the auxiliary valve body 51S that can be controlled independently of the main valve body 51M are used in combination to make it possible to adjust the opening degree of the main valve 51, when decelerating the car body K, it is possible to perform a soft stop without imposing a burden on the inverter. As a result, energy savings can also be promoted for the fine adjustment of the position and speed of the car body.

[0079] In addition, since it is provided with the valve body 51M and the auxiliary valve body 51S that can be controlled independently of the main valve body 51M, it is possible to reduce the frequency difference and phase difference between the regenerative power generated by the motor 90 and the commercial power supply without impairing the riding comfort, so that the regenerative power generated by the motor 90 can be supplied to the commercial power supply via the inverter 96.

[0080] Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention.

Explanation of Reference Numerals

[0081] 2 Hydraulic elevator unit 10 Car body 20 Hydraulic cylinder 30 Hydraulic oil tank unit 40 Hydraulic oil path forming unit 43 Pump 44 Cylinder pipe 45 Interlock valve 46A Direct delivery pipe 46B Route pipe 50 Valve mechanism 51 Main valve 51E Communication path 51L Main valve body solenoid 51M Main valve body 51R Auxiliary valve body solenoid 51S Auxiliary valve body 52 Relief valve 53 Connection flow path 90 Motor 95 Inverter 99 Control mechanism

Claims

1. A hydraulic actuator including a piston that rises with the inflow of hydraulic oil and descends with the outflow of the hydraulic oil, An input unit to which a descent command for the piston is input, A pump that adjusts the amount of the hydraulic oil in the hydraulic actuator for positioning the piston, A motor connected to the pump, A valve mechanism that controls the flow rate of the hydraulic oil between the hydraulic actuator and the pump, A valve control unit that controls the valve mechanism based on the descent command, A hydraulic system comprising: When defining a descent sequence in which the piston descends, respectively, An acceleration mode in which the descent speed of the piston gradually increases, A deceleration mode in which the descent speed gradually decreases, A constant speed mode that is between the acceleration mode and the deceleration mode and in which the descent speed is a target value, The valve control unit controls the valve mechanism based on the descent command so that the frequency of the regenerative power generated from the motor in the constant speed mode becomes a target value, The flow rate of the hydraulic oil passing through the pump in the constant speed mode is set corresponding to the target value of the frequency of the regenerative power generated from the motor. A hydraulic system characterized by this.

2. The motor is connected to an inverter, The inverter is connected to a commercial power source, The target value is the frequency of the commercial power source input to the inverter The hydraulic system according to claim 1, characterized by this.

3. A commercial power source management unit that reads the frequency of the commercial power source input to the inverter, A regenerative power management unit that reads the frequency of the regenerative power generated from the motor, A frequency determination unit that determines whether or not the difference between the frequency of the regenerative power and the frequency of the commercial power supply is within an allowable range. The hydraulic system according to claim 2, characterized in that.

4. It includes a phase difference determination unit that determines whether or not the phase difference between the frequency of the commercial power supply and the frequency of the regenerative power is within an allowable range. The commercial power supply management unit reads the phase of the commercial power supply. The regenerative power management unit reads the phase of the regenerative power. The valve control unit controls the valve mechanism so as to cancel out the phase difference between the regenerative power and the commercial power in the constant speed mode. The hydraulic system according to claim 3, characterized in that.

5. The hydraulic system according to claim 4, characterized in that the valve control unit controls the valve mechanism in the acceleration mode so as to cancel out the phase difference between the regenerative power and the commercial power in the constant speed mode.

6. The hydraulic system according to claim 5, characterized in that the valve control unit cancels out the phase difference by adjusting the start timing of the acceleration mode.

7. The hydraulic system according to claim 5, characterized in that the valve control unit cancels out the phase difference by adjusting the start timing of the constant speed mode.

8. The hydraulic system according to any one of claims 1 to 7, and A cage chamber provided on the piston and moving vertically by the hydraulic system. A hydraulic elevator unit characterized by comprising.

9. The valve mechanism is A valve block, A first liquid passage port formed in the valve block, A second liquid passage port formed in the valve block, A communication passage that connects the first liquid passage port and the second liquid passage port, A main valve body disposed in the communication passage, A sub-valve body provided on the valve block, and the sub-valve body is switchable between a protruding state in which it protrudes from the wall surface of the communication passage and a protruding retracted state in which it has retracted from the protruding state, the main valve body is switchable between a contact state in which it contacts the sub-valve body and a contact retracted state in which it has retracted from the contact state, the communication passage is an open state in which the main valve body is in the contact retracted state, a slightly open state in which the sub-valve body is in the protruding state and the main valve body is in the contact state, a closed state in which the sub-valve body is in the protruding retracted state and the main valve body is in the contact state, and is switchable therebetween, in the constant speed mode, the communication passage is in the open state, in the deceleration mode, the communication passage is in the slightly open state, when the car chamber stops, the communication passage is in the closed state The hydraulic elevator system according to claim 8, characterized in that.

10. An input step of receiving an input of a descending command, A descending command storage step of storing the descending command in a storage device, A valve control step of controlling the valve mechanism based on the descending command, A control program for a hydraulic system for causing a computer to execute, the hydraulic system is A hydraulic actuator including a piston that rises by the inflow of hydraulic oil and descends by the outflow of the hydraulic oil, A pump that adjusts the amount of the hydraulic oil in the hydraulic actuator for positioning the piston, A motor connected to the pump, The inverter that is connected to the motor and is connected to a commercial power supply, A valve mechanism that controls the flow rate of the hydraulic oil between the hydraulic actuator and the pump, A valve control unit that controls the valve mechanism based on the lowering command, When the lowering sequences in which the piston descends are respectively defined as, An acceleration mode in which the lowering speed of the piston gradually increases, A deceleration mode in which the lowering speed gradually decreases, A constant speed mode that is between the acceleration mode and the deceleration mode and in which the lowering speed is a target value, In the valve control step, based on the lowering command, the valve mechanism is controlled so that the frequency of the regenerative power generated from the motor in the constant speed mode becomes the target value, In the constant speed mode, the flow rate of the hydraulic oil passing through the pump corresponds to the target value of the frequency of the regenerative power generated from the motor, The target value is the frequency of the commercial power supply input to the inverter. A control program for a hydraulic system, characterized in that.

11. In the valve control step, The frequency of the commercial power supply input to the inverter is read, The frequency of the regenerative power generated from the motor is read, It is determined whether the difference between the frequency of the regenerative power and the frequency of the commercial power supply is within an allowable range. The control program for a hydraulic system according to claim 10, characterized in that.

12. In the valve control step, The commercial power supply management unit reads the phase of the commercial power supply, The regenerative power management unit reads the phase of the regenerative power, It is determined whether the phase difference between the frequency of the commercial power supply and the frequency of the regenerative power is within an allowable range, Controlling the valve mechanism so as to cancel out the phase difference between the regenerative power and the commercial power in the constant speed mode The control program for a hydraulic system according to claim 11, characterized in that.

13. A valve mechanism for controlling the flow rate of hydraulic oil in a hydraulic elevator system, A valve block, A first liquid passage port formed in the valve block, A second liquid passage port formed in the valve block, A communication passage connecting the first liquid passage port and the second liquid passage port, A main valve body disposed in the communication passage, A sub-valve body provided on the valve block, comprising: The sub-valve body is switchable between a protruding state protruding from the wall surface of the communication passage and a protruding retracted state retracted from the protruding state, The main valve body is switchable between a contacting state contacting the sub-valve body and a contacting retracted state retracted from the contacting state, The communication passage is An open state in which the main valve body is in the contacting retracted state, A slightly open state in which the sub-valve body is in the protruding state and the main valve body is in the contacting state, A closed state in which the sub-valve body is in the protruding retracted state and the main valve body is in the contacting state, and is switchable therebetween, In the constant speed mode, the communication passage is in an open state, In the deceleration mode, the communication passage is in a slightly open state, When the car chamber stops, the communication passage is in a closed state A valve mechanism characterized by that.

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