JP2004239392A - Hydraulic pressure unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic pressure unit capable of accumulating the stable energy effectively in an accumulator. <P>SOLUTION: This hydraulic pressure unit comprises a hydraulic pressure pump motor 11 that is driven by a drive source 10 and produces the hydraulic power, a loading unit 12 that uses the hydraulic power of the hydraulic pressure pump motor, an accumulator 31 that is connected to the hydraulic pressure pump motor and the oil channel of the loading unit, a check valve 21 that turns the inlet side to the outlet side of the hydraulic pressure pump motor on the side of the oil channel of the hydraulic pressure pump motor and the accumulator, an unloading oil channel that the branches from the oil channel between the oil pressure pump motor and the check valve, the first control valve 1 that is interposed in the unloading channel, the second control valve that is interposed in the oil channel between the accumulator and the loading unit and a pressure sensor 51 that detects the energy quantity accumulated in the accumulator. Switching of the first control valve and the second control valve is controlled on the basis of the detection value of a pressure sensor. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydraulic device, and more particularly, to a hydraulic pump motor driven by a drive source having a moment of inertia and a load having a load driven by pressure generated by the hydraulic pump motor.
[0002]
[Prior art]
A conventional hydraulic device is configured such that a hydraulic pump motor is driven by a driving source having a required amount of inertia inherently or by a load to form a constant-pressure hydraulic source, and peripheral elements according to a required load are further provided. It is possible to supply hydraulic energy to the load by opening and closing the control valve according to the condition of the load including the energy storage device or the hydraulic cylinder so that the hydraulic oil can be supplied to the load from the low pressure and large flow rate to the load. There was a hydraulic device.
[0003]
[Patent Document]
Japanese Patent Application No. 2001-356727 [0004]
[Problems to be solved by the invention]
However, in the hydraulic device having the above-described configuration, the control valve is controlled based on the rotation speed of the drive source, and the pressure value, which is the amount of energy supplied to the load device, fluctuates greatly. That is, if the pressure value fluctuates greatly, stable energy supply cannot be performed according to the amount of energy required by the load device.
[Means for Solving the Problems]
[0005]
The present invention has been made to solve the problem of the conventional configuration, and has a pressure sensor and a timer for detecting the amount of energy stored in the accumulator in order to supply stable energy. The opening and closing control of the first control valve is performed.
That is, the present invention provides a drive source having a required amount of inertia inherently or additionally, a hydraulic pump motor driven by the drive source, and an oil passage connected from the discharge side of the hydraulic pump motor to the inflow side of the load device. A check valve with the input side facing the discharge port side of the hydraulic pump motor in the oil passage, an unload oil passage branching from the oil passage between the hydraulic pump motor and the check valve, and an intervening oil passage in the unload oil passage A first control valve, an oil passage that guides the passage side of the first control valve to the hydraulic oil tank, an accumulator connected to the oil passage on the output side of the check valve, and an accumulator and a load device. A second control valve interposed in the oil passage, a pressure sensor for detecting an amount of energy stored in an accumulator, the first control valve and the second control based on a detection value of the pressure sensor. Controls valve switching It is characterized in a hydraulic apparatus comprising a control unit.
With this configuration, since the amount of energy stored in the accumulator can be accurately grasped, it is possible to constantly control the accumulation of stable energy in the accumulator.
[0006]
The control unit includes a first timer and a second timer. When the detection value from the pressure sensor becomes equal to or less than a specified value, the control unit starts the first timer and switches the first control valve to a blocking side to switch the first control valve to the blocking side. By starting the second timer based on the expiration of the timer and performing control to switch the first control valve to the passing side until the second timer expires, it is necessary for the accumulator Is preferable because the energy to be supplied can be supplied efficiently.
The timer set value is determined by the supply oil amount of the hydraulic pump motor, the required oil amount on the load side, and the preload set value of the accumulator.
In this configuration, when the amount of energy stored in the accumulator falls below or possibly falls below the amount of energy required by the load, the first control valve is opened / closed based on a timer to control opening and closing. It is possible to efficiently and stably supply energy.
BEST MODE FOR CARRYING OUT THE INVENTION
[0007]
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing components of a hydraulic device and a hydraulic circuit formed by flow paths connecting the components.
[0008]
The drive source 10 uses an electric motor here. An inertia body, specifically, a flywheel 71 is attached to the shaft of the drive source 10. When the flywheel 71 is rotationally driven by the drive source 10, rotational energy is accumulated by inertia. A shaft is connected to the center of the flywheel 71, and a driving force from a drive source 10 is transmitted to the hydraulic pump motor 11 through the shaft, and the hydraulic pump motor 11 is driven. When the drive source 10 has a large moment of inertia, that is, when the drive source 10 has an inertia, the flywheel 71 can be omitted.
[0009]
The hydraulic pump motor 11 is connected to the driving source 10 directly or via a flywheel 71, and draws hydraulic oil from the hydraulic oil tank 40 with the driving of the driving source 10 to the inflow side of the solenoid-type second control valve 2. The hydraulic oil is discharged into the formed conduit 101.
[0010]
The first control valve 1 is a solenoid-type control valve, is connected from a pipe 101 via a branch point 61, and passes through the first control valve 1 to the hydraulic oil tank 40 to unload an oil passage 102. It is provided inside.
[0011]
The check valve 21 is provided on a pipe line 101 on the downstream side from the branch point 61 to the second control valve 2 with the input side facing the branch point 61.
[0012]
The accumulator 31 is provided on a conduit 103 between the check valve 21 and the second control valve 2 via a connection point 62.
[0013]
Here, the check valve 21 has a function of preventing the hydraulic oil accumulated in the accumulator 31 from flowing back to the hydraulic pump motor 11 side.
[0014]
The hydraulic cylinder 12 is provided with the inflow side facing a conduit 104 extending from the outflow port of the second control valve 2. A hydraulic oil tank 40 is provided on the outflow side of the hydraulic cylinder 12. In the present invention, the load will be described as a hydraulic cylinder 12.
[0015]
The control unit 80 controls the opening and closing of the first and second control valves and inputs a detection signal from the pressure sensor 51 that detects the pressure value of the hydraulic oil accumulated in the accumulator 31 to thereby control the pressure value of the accumulator. It is composed of a microcomputer or the like that enables monitoring.
Here, the control unit 80 constantly or intermittently monitors the detection signal from the pressure sensor 51 and performs opening / closing control of the first control valve 1 and the second control valve. Specifically, a table is provided in which timers 1 and 2 corresponding to detection values according to the detection signal from the pressure sensor 51 are set in advance, and the opening and closing control of the first control valve is controlled based on the values in the table. Do.
[0016]
Next, how the respective components described in the preceding paragraph operate the hydraulic cylinder 12, which is a load, will be described. When the drive source 10 is started and the hydraulic pump motor 11 is operating at the set rotation speed, the hydraulic oil is sucked from the hydraulic oil tank 40 into the hydraulic pump motor 11. The hydraulic oil sucked into the hydraulic pump motor 11 is discharged from the hydraulic pump motor 11 and flows from the discharge-side pipe 101 to the hydraulic oil tank 40 through the pipe 102 and the first control valve 1. Here, the control circuit extracts the first and second timer values according to the detection signal value of the pressure sensor 51 from the on-off valve control table.
The extracted values are set in a first timer and a second timer. Further, after setting, the timer is started and the first control valve 1 is switched to the blocking side for the time until the end of the first timer. Further, control is performed to start the second timer in response to the end of the first timer, and to switch the first control valve 1 to the passage side for the time until the end of the second timer.
[0017]
When the first control valve 1 is in the position on the passage side based on the control of the control unit 80, the pipeline connecting to the pipeline 102, the first control valve 1 and the hydraulic oil tank 40 forms an unloading hydraulic channel. I do. In this state, when the position of the first control valve 1 is switched from the passing side to the blocking side based on the end of the first timer in the control unit 80, the hydraulic oil is driven by the hydraulic pump motor 11 driven by the drive source 10. , Through the check valve 21 connected to the downstream side of the connection point 61 in the pipeline 101, and is supplied to the load side. When the position of the first control valve 1 is switched from the passing side to the blocking side, the discharge pressure that can be continuously generated by the hydraulic pump motor 11 driven at the set rotation speed by the drive source 10, ie, the hydraulic pump motor 11 A pressure higher than the discharge pressure generated during the normal operation of. This high-pressure hydraulic oil is supplied to the accumulator 31 when the position of the second control valve 2 is on the blocking side, and the hydraulic oil, that is, energy is accumulated in the accumulator.
[0018]
The reason why the high pressure is generated will be described in more detail. When the torque that can be generated is Qm and the torque of the hydraulic pump motor 11 driven by the drive source 10 is Qp, the relationship of Qm = Qp is established if the loss is ignored. Is obvious. Here, assuming that the moment of inertia of the drive source 10 is I and the angular velocity is ω, the inertia torque required when the drive source 10 accelerates or decelerates can be expressed by I · dω / dt. Note that I · dω / dt has a value of + during acceleration and a value of − during deceleration.
[0019]
In the present embodiment, when the position of the first control valve 1 is on the passage side, the drive source 10 controls based on the rotation speed from a tachometer (not shown) so as to maintain the set rotation speed. Is done. When the position of the first control valve 1 is switched to the blocking side, the hydraulic pump motor 11 receives a load and the drive source 10 is decelerated, but as described above, the inertia torque I · dω / dt is added to Qm, and the relationship of Qp = Qm−I · dω / dt is established. Therefore, a torque larger than the input torque Qm of the hydraulic pump motor 11 during normal operation is input to the hydraulic pump motor 11 by adding the inertia torque due to the deceleration of the drive source 10. On the other hand, the discharge pressure of the hydraulic pump motor 11 increases according to the load pressure. As a result, the hydraulic oil whose pressure has increased is supplied to the load on the downstream side.
[0020]
Although the description so far has been made only when the operation of switching the position of the first control valve 1 from the passing side to the blocking side is performed only once, the switching from the blocking side to the passing side is performed and the switching to the blocking side is performed again. The operation can be repeated.
[0021]
As described above, in the present embodiment, since a high hydraulic pressure can be supplied by a smaller drive source, the drive can be performed without providing a drive source having an output torque corresponding to the maximum load torque required by the load. It is possible and has great economic benefits.
[0022]
Next, the output side of the check valve 21 will be described. An accumulator 31 is connected to the output side of the check valve 21, and the operation in which the first control valve 1 switches from the passage side to the blocking side to increase the pressure is performed. Oil can flow in the accumulator and store energy.
The energy stored in the accumulator and the hydraulic oil pressure in the conduit 103 can be detected by the pressure sensor 51.
[0023]
Subsequently, the value detected by the pressure sensor is transmitted to the control unit 80, and the control unit determines whether or not the value has reached a value corresponding to the energy required by the load device. If the value is equivalent to the energy amount, the control unit 80 performs control to switch the second control valve 2 from the blocking side to the passing side. Further, by switching the second control valve 2 to the passage side, hydraulic oil flows from the accumulator 31 into the hydraulic cylinder, and the hydraulic cylinder operates. The hydraulic oil that has operated the hydraulic cylinder is discharged from the hydraulic cylinder and flows to the hydraulic oil tank 40.
[0024]
As described above, once the energy generated by the drive source 10 is accumulated in the accumulator, a high energy amount exceeding the range that can be generated by the drive source can be efficiently supplied to a load device that is a hydraulic cylinder here. .
[0025]
FIG. 2 is a flowchart illustrating the operation of the control unit 80 that controls the hydraulic device. The operation of the first control valve and the second control valve of the present invention will be described in detail based on this flowchart. The load device of the embodiment uses a hydraulic cylinder and is configured to be operated when necessary. That is, the second control valve is switched to the passage side and the hydraulic oil is supplied only when it is needed, not when it is constantly operating. Of course, when the energy required by the hydraulic cylinder is not stored in the accumulator, the second control valve is not switched to the passage side.
[0026]
In operating the drive source in S301, the first control valve 1 is switched to the passing side and the second control valve 2 is switched to the blocking side.
Next, the driving source is operated in S302. Thereby, the flywheel 71 and the hydraulic pump motor connected to the shaft of the drive source 10 start 11 rotations. Subsequently, the hydraulic pump motor 11 sucks up the hydraulic oil from the hydraulic oil tank 40 and discharges the hydraulic oil to the discharge line 101 of the hydraulic pump motor 11. The hydraulic oil discharged from the hydraulic pump motor 11 flows through the pipeline 101 and the pipeline 102, passes through the first control valve 1, and flows into the hydraulic oil tank 40. That is, an unload state, that is, a state in which the load of the hydraulic pump motor 11 is removed is formed. Here, sufficient inertia torque is provided by increasing the rotation speed of the drive source. Although not shown, the hydraulic oil tank 40 includes a hydraulic oil tank 40 connected to the first control valve, a hydraulic oil tank 40 connected to the hydraulic pump motor 11, and a hydraulic oil tank connected to the hydraulic cylinder 12. 40.
[0027]
Next, in S303, the first control valve 1 is switched to the blocking side. By this switching operation, the hydraulic oil whose pressure has been increased by the hydraulic pump motor 11 driven by the drive source 10 passes through the check valve 21 and is supplied to the output side of the check valve 21. Subsequently, the hydraulic oil supplied to the output side of the check valve 21 loses its place due to the switching of the second control valve 2 to the blocking side, and flows into the accumulator 31. Further, the check valve 21 has a function of preventing the hydraulic oil passing through the check valve 21 from flowing back to the input side of the check valve 21.
[0028]
Next, in S304, it is determined whether or not the detection value from the pressure sensor 51 and the energy amount required by the load device are satisfied. If the determination in S304 is “Y”, the control process is performed to switch the first control valve 1 to the passing side in S305, and the process proceeds to the determination step in S304 again, where an unload is formed and the drive source has an inertia torque. To increase the number of revolutions.
[0029]
Next, if the determination in S304 is “N”, that is, if the energy amount required by the load device is not accumulated in the accumulator 30, the detection of the pressure sensor 51 is performed based on the on-off valve control table shown in FIG. The first timer value and the second timer value corresponding to the values are obtained, and the respective timers are set. It is assumed that optimal values of the first timer and the second timer are stored in the control unit 80 based on previous experimental data.
[0030]
Next, in S307, the first timer is started, and in S308, the first control valve 1 is switched to the blocking side. In S309, this state is maintained until the first timer times out. As a result, the hydraulic oil whose pressure has been increased by the hydraulic pump motor 11 driven by the drive source 10 passes through the check valve 21, is supplied to the output side of the check valve 21, and is supplied to the output side of the check valve 21. The hydraulic oil loses its place because the second control valve 2 is switched to the blocking side 2b, and flows into the accumulator 31 to store energy. There is no problem even if S307 and S308 are reversed. It is also assumed that each timer is decremented at the same time as the start.
[0031]
Next, when the time-up of the first timer is detected in S309, the second timer is started in S310, the first control valve 1 is switched to the passing side in S311, and the time-out of the second timer is performed in S312. This state is maintained until. In this way, a process of increasing the number of revolutions is performed in order to form an unload and provide the drive source with an inertia torque.
[0032]
Next, by detecting the second timer time-up in S312, the process returns to S304 again to determine whether or not the detected value from the pressure sensor 51 and the energy amount required by the load device are satisfied. That is, S306, S307, S308, S309, S310, S311 and S312 are repeated until the energy amount required by the load device is satisfied. Thus, by constantly monitoring the output value of the pressure sensor 51, it is possible to maintain a state where stable energy can be supplied to the load device.
[0033]
Although the first timer and the second timer are described separately in the embodiment, it is also possible to control with one timer without dividing the timer. In this case, after setting the first timer value in the timer, the second timer value may be set in the timer based on the expiration of the timer.
[0034]
【The invention's effect】
As described above, the hydraulic device of the present invention controls the opening and closing of the first control valve and the second control valve to generate high energy that cannot be generated by the drive source alone, thereby transferring the energy required by the load device to the accumulator. Can be accumulated. This eliminates the need to provide a driving source according to the amount of energy required by the load device. In other words, there is no need to use a large motor to generate high energy, so that there is an effect of reducing costs. Further, by detecting the amount of energy stored in the accumulator by the pressure sensor, the first control valve, which has conventionally been controlled to be switched by the rotation speed of the drive source, can be most referenced by referring to the detection value of the pressure sensor. Efficient and stable energy can be stored in the accumulator. That is, since it is possible to store stable energy in the accumulator, there is an effect that stable energy supply to the load device can be realized.
[Brief description of the drawings]
FIG. 1 is a diagram showing components and a hydraulic circuit of a hydraulic device of the present invention.
FIG. 2 is a flowchart showing the operation of the hydraulic device.
FIG. 3 is a data table in which timer values are recorded in the hydraulic device.
[Explanation of symbols]
Reference numerals 1 and 2 denote control valves, 10 drive sources, 11 hydraulic pump motors, 12 hydraulic cylinders, 21 check valves, 31 accumulators, 40 hydraulic oil tanks

Claims (3)

A drive source having a required amount of inertia inherently or additionally;
A hydraulic pump motor driven by the drive source,
An oil passage connected from the discharge side of the hydraulic pump motor to the inflow side of the load device, a check valve having an input side directed to the discharge port side of the hydraulic pump motor in the oil passage,
An unload oil passage branched from an oil passage between the hydraulic pump motor and the check valve, a first control valve interposed in the unload oil passage,
An oil passage for guiding the passage side of the first control valve to a hydraulic oil tank;
An accumulator connected to the oil passage on the output side of the check valve;
A second control valve interposed in the oil passage between the accumulator and the load device;
A pressure sensor for detecting an amount of energy stored in the accumulator,
A hydraulic device comprising: a control unit that performs switching control of the first control valve and the second control valve based on a detection value of the pressure sensor. The control unit includes a first timer and a second timer. When a detection value from the pressure sensor becomes equal to or less than a specified value, the control unit starts the first timer and switches the first control valve to a blocking side. 2. The method according to claim 1, further comprising: starting the second timer based on the expiration of the timer, and performing control to switch the first control valve to the passage side until the second timer expires. Hydraulic device as described. 3. The hydraulic device according to claim 2, wherein the control unit repeats the processing of claim 2 until a detection value from the pressure sensor becomes equal to or greater than a specified value.

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