JPH09255241A - Fluid pressure elevator and its operating method - Google Patents

Abstract

(57) An object of the present invention is to prevent the occurrence of cavitation by preventing an abnormal decrease in the pressure of a conductive fluid. SOLUTION: A detector 10 for detecting a pressure in a fluid passage 7 between an electromagnetic flow rate generator 4 and an on-off valve 5 is provided, and a control device is provided when a detected value of the detector 10 falls below a set value. A stop command is output by 12 to stop the car 1 and stop the operation of the electromagnetic flow rate generator 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid pressure elevator that raises and lowers a car by supplying and discharging a fluid to and from a jack, and a method of operating the same.

[0002]

2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 5-286670 discloses a hydraulic elevator driven by a hydraulic pump. Further, Japanese Patent Laid-Open No. 3-227835 discloses a fluid pressure elevator that supplies and discharges magnetic fluid to and from a jack using an electromagnetic flow rate generator.

The conventional hydraulic control system for a hydraulic elevator includes a system using a flow control valve, a pump control system, and a hydraulic pump drive system based on rotation control of an electric motor. Among these, in the method using the flow control valve, the electric motor is rotated at a constant speed during the ascending operation, and the control valve arranged in the middle of the route for returning the flow rate of the hydraulic oil discharged from the hydraulic pump to the oil tank is throttled. As a result, all or part of the hydraulic oil is sent to the hydraulic jack. Also, during the descent operation, the flow rate of the hydraulic oil due to the weight of the car is adjusted by the flow control valve to control the speed of the car. However, in this method, extra hydraulic oil is circulated during the ascending operation, and the potential energy is converted into heat generation of the hydraulic oil during the descending operation, resulting in large energy consumption and a large increase in the oil temperature.

In order to make up for this drawback, there is a system in which only the required amount of oil is sent to the hydraulic jack during ascending operation, and the electric motor is regeneratively braked during descending operation. That is, during the ascending operation, the hydraulic pump is driven by the electric motor to send the pressure oil to the hydraulic jack, and during the descending operation, the hydraulic pump is rotated by the pressure oil to drive the electric motor to regenerate electric power.

Further, in the conventional fluid pressure elevator, a safety valve is provided at the time of operation for increasing the pressure of hydraulic oil. In other words, when the pressure in the hydraulic circuit rises abnormally during the raising operation of the car, the safety valve is opened and the working oil discharged from the pump is returned to the oil tank to suppress further pressure rise. is there.

[0006]

Among the conventional fluid pressure elevators as described above, in the one in which fluid is supplied to and discharged from the jack for raising and lowering the car by the electromagnetic flow rate generator, the electromagnetic flow rate is generated during the descending operation. If the on-off valve between the device and the jack cannot be opened due to some failure, the fluid will only come out from the passage between the on-off valve and the electromagnetic flow rate generator and will not enter. In such a case, when the pressure in the passage decreases to a predetermined value or less, a cavitation phenomenon occurs in the fluid, abnormal vibration occurs in the hydraulic equipment, and the hydraulic equipment may be damaged in some cases.

The present invention has been made to solve the above problems, and a fluid pressure elevator capable of detecting an abnormal decrease in pressure in a fluid passage and preventing the occurrence of cavitation. And to obtain its operating method.

[0008]

According to a first aspect of the present invention, there is provided a fluid pressure elevator comprising: a jack for raising and lowering a car; a tank for containing a conductive fluid supplied to the jack; and a jack and a tank. Detecting the pressure in the electromagnetic flow generator between the electromagnetic flow generator and the jack, which is installed in the electromagnetic flow generator that raises and lowers the cage by driving the conductive fluid by applying magnetic flux and direct current. And a controller that outputs a stop command when the detected value of the detector falls below a set value to stop the car and stop the operation of the electromagnetic flow rate generator. .

In the fluid pressure elevator according to the second aspect of the present invention, the on-off valve is provided between the jack and the electromagnetic flow rate generator, and the pressure in the fluid passage between the electromagnetic flow rate generator and the on-off valve is It is detected by a detector.

In the method for operating a fluid pressure elevator according to a third aspect of the present invention, the pressure in the fluid passage between the jack and the electromagnetic flow rate generator is detected by a detector when the car is descending, and the detected value is When it becomes lower than the set value, a stop command is output to stop the car and stop the operation of the electromagnetic flow rate generator.

According to a fourth aspect of the present invention, in the method for operating a fluid pressure elevator, the electromagnetic flow rate generator is closer to the electromagnetic flow generator than the on-off valve provided between the jack and the electromagnetic flow rate generator after the descent operation command is output. The pressure on the electromagnetic flow generator side of the on-off valve is detected by the detector after a lapse of time until the pressure on the side becomes equal to the pressure on the jack side.

In the fluid pressure elevator according to the invention of claim 5, when the value detected by the detector is lower than the set value,
The electromagnetic flow rate generator is controlled to suppress the flow rate of the conductive fluid that returns to the tank.If the detected value returns to normal by this flow rate control, operation continues, and if it does not return to normal within the specified time, a stop command is issued. It is what is output.

A fluid pressure elevator according to a sixth aspect of the present invention controls the flow rate of the conductive fluid returning to the tank by controlling at least one of the magnetic flux and the direct current applied to the conductive fluid.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1. 1 is a hydraulic circuit diagram of a fluid pressure elevator according to Embodiment 1 of the present invention. In the figure, 1 is a car, 2 is a jack for raising and lowering the car 1, 3 is a tank in which a conductive fluid as a working fluid is stored, and the conductive fluid is, for example, magnetic powder obtained by mixing magnetic metal powder and fluid. Fluid or water is used. 4 is provided between the tank 3 and the jack 2, and 5 is provided between the electromagnetic flow generator 4 and the jack 2 for supplying and discharging a conductive fluid to and from the jack 2. It is an on-off valve.

6 is a first fluid passage connecting the tank 3 and the electromagnetic flow rate generator 4, 7 is a second fluid passage connecting the electromagnetic flow rate generator 4 and the on-off valve 5, and 8 is an on-off valve 5. A third fluid passage connecting the jack 2, a relief valve 9 connected in parallel with the electromagnetic flow rate generator 4 between the tank 3 and the on-off valve 5, and 10 a pressure in the second fluid passage 7. Is a first detecting device for detecting the pressure, 11 is a second detecting device for detecting the pressure in the third fluid passage 8, and 12 is connected to the electromagnetic flow rate generator 4, the on-off valve 5, and the respective detecting devices 10, 11. Control device.

FIG. 2 is an explanatory view for explaining the operating state of the electromagnetic flow rate generator 4 of FIG. 1 during the ascending operation. In the figure,
Reference numerals 13 and 14 denote positive and negative electrodes for flowing a direct current through the conductive fluid, and 15 is an electromagnetic coil for generating a magnetic flux in the direction perpendicular to the direct current.

Next, the operation will be described. First, when raising the car 1, the magnetic flux is passed through the conductive fluid by the electromagnetic coil 15, and then the direct current is passed through the positive electrode 13 and the negative electrode 14. When the direction of the current flowing through the electromagnetic coil 15 is the direction of arrow A in FIG. 2 and the direction of the direct current is the direction of arrow B, the conductive fluid flows in the direction of arrow C, that is, in the supply direction to the jack 2 according to Fleming's left-hand rule. . Therefore, when the flow rate of the direct current is gradually increased, the flow rate of the conductive fluid supplied to the jack 2 increases, and the car 1 is accelerated in the upward direction.

After that, when the rising speed reaches the maximum speed,
By keeping the direct current constant and the flow rate of the fluid supplied to the jack 2 constant, the car 1 is operated at high speed.
When the vehicle reaches a predetermined position before the destination floor, the DC current is gradually reduced to reduce the flow rate of the fluid supplied to the jack 2, so that the car 1 is decelerated in the ascending direction and then stopped at the destination floor. After the car 1 is stopped, the on-off valve 5 is closed and the operation of the electromagnetic flow rate generator 4 is stopped.

During such an ascending operation, if the pressure in the second fluid passage 7 rises abnormally due to some failure, the relief 9 is opened and at least a part of the fluid that has passed through the electromagnetic flow generator 4 is released. It is returned to the tank 3 and further pressure increase is suppressed.

On the other hand, when lowering the car 1, the on-off valve 5
With the valve closed, the electromagnetic flow rate generator 4 is operated to flow the fluid from the first fluid passage 6 to the second fluid passage 7 side and gradually increase the flow rate. As a result, the pressure in the second fluid passage 7 gradually rises. At this time, the pressure in the second fluid passage 7 is monitored by the first detection device 10, and the pressure in the jack 2 generated by the weight of the car 1, that is, the pressure detected by the second detection device 11 is detected. 3 and the pressure in the fluid passage 8 is compared. Then, when the pressure difference in the second and third fluid passages 7 and 8 falls within a predetermined value, the on-off valve 5
Is released and the descending operation is performed.

In order to perform the descending operation, the conductive fluid of the jack 2 may be returned to the tank 3 as opposed to the ascending operation.
The direction of the direct current or the direction of the magnetic flux in the electromagnetic flow rate generator 4 may be reversed from that at the time of rising. Here, it is assumed that the direction of the magnetic flux is reversed. In this state, if the direct current is increased, the car 1 is accelerated in the descending direction. After that, when the speed of the car 1 reaches the maximum speed, the car 1 is operated at high speed by keeping the flow rate of the fluid returned to the tank 3 constant. Further, during the descending operation, the first fluid from the second fluid passage 7
Since the fluid flows toward the flow passage 6 of No. 3, an electromotive force is generated from the electrode 14 toward the electrode 13 according to Fleming's right-hand rule, and operation is performed in a so-called power regeneration mode.

After that, when the vehicle reaches a predetermined position before the destination floor, a deceleration command is issued and the flow rate of the fluid flowing from the second fluid passage 7 to the first fluid passage 6 is gradually reduced. It is decelerated. Open / close valve 5 after car 1 stops
Is closed and the operation of the electromagnetic flow rate generator 4 is stopped.

FIG. 3 is a relationship diagram showing changes in the speed of the car 1 and the opening degree of the opening / closing valve 5 during the descending operation, and FIG. 4 shows the pressure in the second and third fluid passages 7 and 8 during the descending operation. It is a relationship diagram which shows change.

Here, if the open / close valve 5 does not open at all or does not open sufficiently for some reason during the descent operation of the car 1, the pressure in the second fluid passage 7 decreases. There is a risk that cavitation will occur. On the other hand, in this example, the first detection device 1
Since 0 is provided, it is possible to prevent the pressure in the second fluid passage 7 from dropping below the set value.

FIG. 5 is a flow chart for explaining an example of the operation of the control device 12. When the descending operation command is output, it is first confirmed whether or not the time T1 in FIG. 4 has elapsed (step S1). This time T1 is the second
Is a time until the pressure in the fluid passage 7 becomes equal to the pressure in the third fluid passage 8, and since the set pressure is passed during this time, this time T1 is masked to prevent a malfunction immediately after startup. .

Next, it is confirmed whether the detection value of the first detector 10 is equal to or more than the set value (step S2). This confirmation is repeatedly performed until the car stop command is output. That is, the pressure monitoring is continuously performed during the time T2 in FIG. When the car stop command is output (step S3), the monitoring ends. When the pressure drops below the set value, a stop signal is output (step S4), the car 1 is safely stopped, and a signal for closing the on-off valve 5 is output.
Driving is also stopped.

Therefore, the pressure in the second fluid passage 7 is stabilized at the normal pressure (almost atmospheric pressure) when the operation is stopped without lowering to a negative pressure that causes cavitation. In this state, the on-off valve 5 and other devices are inspected.

Embodiment 2 FIG. 6 is a flowchart for explaining another example of the operation of the control device 12. In this example, when the detected value of the first detector 10 becomes abnormal, the stop signal is not output immediately and it is confirmed whether the abnormal situation continues for a predetermined time (step S
5) If it is not continued, the electromagnetic flow rate generator 4 is controlled so as to suppress the flow rate of the fluid returned to the tank 3 without outputting a stop signal (step S6). By such control, if the detected value returns to normal, the operation is continued as it is, and if it does not return to normal even after controlling for a predetermined time, a stop signal is output (step S4).

By performing such control, for example, when the operation of the opening / closing valve 5 is temporarily delayed due to some reason,
For troubles that can be recovered naturally, it is possible to automatically recover without stopping the operation and prevent a decrease in operation efficiency. The flow rate can be effectively suppressed by controlling at least one of the magnetic flux and the direct current.

Embodiment 3 FIG. 7 is a flow chart for explaining still another example of the operation of the control device 12. In the example of FIG. 6, the stop signal is output according to the abnormal continuation time, but in this example, the stop signal is output according to the number of times of flow rate suppression. That is, when an abnormality is detected, the number of times is counted by the counter (step S7), and it is confirmed whether or not the set number of times X is reached (step S8). If the set number of times has not been reached, the electromagnetic flow rate generator 4 is controlled so as to suppress the flow rate of the fluid returned to the tank 3 (step S6).
By such control, if the detected value returns to normal, the operation is continued as it is, and if it does not return to normal even after controlling for a predetermined number of times, a stop signal is output (step S4). Even with such a control method, the same effect as that of the second embodiment can be obtained.

Embodiment 4 FIG. Although the on-off valve 5 is provided between the jack 2 and the electromagnetic flow rate generator 4 in the above example, the on-off valve 5 can be omitted as shown in FIG. 8, for example. In this case, it is necessary to always generate a force for supporting the own weight of the car 1 by the electromagnetic flow rate generator 4 while the car 1 is stopped. Also in this example, the occurrence of cavitation can be prevented by detecting the pressure in the fluid passage 8 with the detector 10 and performing the control shown in FIGS. 5 to 7.

[0032]

As described above, the fluid pressure elevator according to the first aspect of the present invention is provided with the detector for detecting the pressure in the fluid passage between the electromagnetic flow rate generator and the jack, and the detector detects the pressure. When the value falls below the set value, the controller outputs a stop command to stop the car and the operation of the electromagnetic flow rate generator.Therefore, abnormal pressure drop of the conductive fluid is prevented and cavitation Occurrence is prevented.

According to another aspect of the fluid pressure elevator of the present invention, an on-off valve is provided between the jack and the electromagnetic flow rate generator, and the pressure in the fluid passage between the electromagnetic flow rate generator and the on-off valve is detected by a detector. Therefore, it is possible to prevent the occurrence of cavitation due to the abnormality of the on-off valve during the descent operation.

In the operating method of the fluid pressure elevator according to the third aspect of the present invention, the stop command is issued when the pressure in the fluid passage between the jack and the electromagnetic flow rate generator is lower than the set value during the downward operation of the car. Since the output is performed and the car is stopped and the operation of the electromagnetic flow rate generator is stopped, the abnormal decrease in the pressure of the conductive fluid is prevented and the occurrence of cavitation is prevented.

In the operating method of the fluid pressure elevator according to the fourth aspect of the present invention, after the downward operation command is output, the electromagnetic flow rate generator side is closer to the electromagnetic flow rate generator side than the on-off valve provided between the jack and the electromagnetic flow rate generator. Since the detector detects the pressure on the electromagnetic flow rate generator side rather than the opening / closing valve after a lapse of time until the pressure becomes equal to the pressure on the jack side, it is possible to prevent a malfunction immediately after the operation command.

In the fluid pressure elevator according to the fifth aspect of the present invention, when the value detected by the detector is lower than the set value, the electromagnetic flow generator is controlled so as to suppress the flow rate of the conductive fluid returning to the tank. If the detected value returns to normal by controlling the flow rate, operation continues, and if it does not return to normal within a predetermined time, a stop command is output, so a stop command is output for a non-sustainable failure that can be restored naturally. It is possible to avoid the above and maintain the operation efficiency of the elevator.

In the fluid pressure elevator according to the sixth aspect of the present invention, the flow rate of the conductive fluid returning to the tank is suppressed by controlling at least one of the magnetic flux and the direct current applied to the conductive fluid. The flow rate can be effectively suppressed.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit diagram of a fluid pressure elevator according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram showing an operating state of the electromagnetic flow rate generator of FIG. 1 during a rising operation.

FIG. 3 is a relationship diagram showing changes in the speed of the car and the opening degree of the opening / closing valve during the descending operation.

FIG. 4 is a relationship diagram showing changes in pressure in the second and third fluid passages during a descent operation.

FIG. 5 is a flowchart for explaining an example of the operation of the control device.

FIG. 6 is a flowchart for explaining another example of the operation of the control device.

FIG. 7 is a flowchart for explaining still another example of the operation of the control device.

FIG. 8 is a hydraulic circuit diagram of a fluid pressure elevator according to Embodiment 4 of the present invention.

[Explanation of symbols]

1 basket, 2 jacks, 3 tank, 4 electromagnetic flow rate generator, 5 on-off valves, 6, 7, 8 fluid passage, 10 first detector, 12 control device.

Claims (6)

[Claims] 1. A jack for raising and lowering a car by supplying and discharging a conductive fluid, a tank for containing the conductive fluid, and a conductive fluid provided between the jack and the tank. An electromagnetic flow rate generator that drives the conductive fluid to raise and lower the car by applying a magnetic flux and a direct current to the detector; and a detector that detects the pressure in the fluid passage between the electromagnetic flow rate generator and the jack. When the detection value of the detector is lower than a set value, a stop command is output to stop the car, and a controller for stopping the operation of the electromagnetic flow rate generator is also provided. Fluid pressure elevator. 2. An on-off valve is provided between the jack and the electromagnetic flow rate generator, and a pressure in a fluid passage between the electromagnetic flow rate generator and the on-off valve is detected by a detector. The hydraulic elevator according to claim 1, wherein: 3. A jack for raising and lowering a car by supplying / discharging a conductive fluid, a tank for storing the conductive fluid, and a conductive fluid provided between the jack and the tank. In a method of operating a fluid pressure elevator, comprising: an electromagnetic flow rate generator that drives the conductive fluid to raise and lower the car by applying a magnetic flux and a direct current to the jack. The pressure in the fluid passage between the flow rate generator is detected by a detector, and when the detected value falls below a set value, a stop command is output to stop the car and operate the electromagnetic flow rate generator. A method for operating a fluid pressure elevator, characterized in that the operation is stopped. 4. From the output of the descending operation command until the pressure on the electromagnetic flow rate generator side of the on-off valve provided between the jack and the electromagnetic flow rate generator becomes equal to the pressure on the jack side. The method for operating a fluid pressure elevator according to claim 3, wherein the pressure on the electromagnetic flow rate generator side of the on-off valve is detected by a detector after a lapse of time. 5. The electromagnetic flow rate generator is controlled so as to suppress the flow rate of the conductive fluid returning to the tank when the detected value by the detector is lower than a set value, and the detected value becomes normal by suppressing the flow rate. The operation method of the fluid pressure elevator according to claim 3 or 4, wherein the operation is continued if returned, and a stop command is output when the operation is not normally returned within a predetermined time. 6. The operation of a fluid pressure elevator according to claim 5, wherein the flow rate of the conductive fluid returning to the tank is suppressed by controlling at least one of the magnetic flux and the direct current applied to the conductive fluid. Method.