JPH0266083A - Device for controlling hydraulic elevator - Google Patents

Abstract

PURPOSE:To enable an elevator to always travel in a proper speed pattern without being affected by the variation in oil temperature and oil pressure by providing a pattern generating circuit for adding correction to the frequency command from a speed control device so that a hydraulic jack can be lifted up/down in a defined speed pattern, based on a signal from a sensor. CONSTITUTION:Pressure oil and oil quantity which flow into/out of a hydraulic jack 2 are detected by sensors 16, 17 immediately before starting a hydraulic elevator. The signals from these sensors 16, 17 are inputted into a pattern generating circuit 20 to add correction to a frequency command from a speed control device 13 so that the hydraulic jack 2 can be lifted up/down in a defined speed pattern. The rotating speed of an electric motor 7 is controlled in accordance with this corrected speed pattern, to enable a riding cage to be lifted up/down always in a normal speed pattern as a result.

Description

[Detailed description of the invention] CObjective of the invention (Industrial application field) Ru.

(Prior Art) Hydraulic elevators generally employ a flow control method using a flow control valve. In this control method, when the elevator is ascending, the electric motor is rotated at a constant speed Iα, and a constant discharge amount of oil from the hydraulic pump is returned to the tank.When a start command is issued, the returned amount is flowed to the tank. Control the speed of the car by adjusting. When the elevator is going down, the speed of the car is controlled by adjusting the amount of oil that is returned to the tank by the ura in the hydraulic cylinder using the flow control valve due to the car's own weight.

However, this control method has the problem that excess oil needs to be circulated when ascending, and when descending, potential energy is consumed by heat generation of the oil, resulting in large energy loss, and the oil temperature rises significantly. .

On the other hand, in recent years, with advances in semiconductor technology, it has become possible to control the rotation speed of induction motors over a wide range by changing the voltage and frequency. A so-called electric motor rotation speed control method has been devised to control the elevator using the motor speed.

This method uses a constant discharge hydraulic pump and performs variable control by changing the pump discharge amount to the rotational speed of the electric motor. FIG. 7 shows a conventional example of a control device for a hydraulic elevator that employs such an electric motor rotation speed control method. In FIG. 7, 1 is an elevator car, 2 is a hydraulic jack with a built-in plunger 3, 4 is a sheave attached to the upper part of the plunger 3; 5 is a lobe placed over the sheave 4; one end of this lobe 5 is tied to the basket 1, and the loose end is tied to the foundation 6.

7 is an AC induction motor directly connected to the hydraulic pump 8; 9 is an electromagnetic switching valve disposed between the hydraulic jack 2 and the hydraulic pump 8; 10 is a tank; 11 is a power source; 12 is connected to the motor 7 and the power source 11. VVVF to control the voltage and frequency
13 is a speed control device that controls the frequency control device 12. Furthermore, 14 is a deceleration switch, and 15 is a stop t switch.

To explain the operation of such a conventional hydraulic elevator control device, the electromagnetic switching valve 9 is closed 7 when the car 1 is stopped, and is opened when the solenoid is energized by an operation command. On the other hand, this operation command causes electricity!
l]g17 rotates, but at this time the speed control device 13
The frequency of the power source 11 is controlled, the rotational speed of the electric motor 7 is controlled, and the rotational speed of the hydraulic pump 8, and therefore the amount of pressure oil discharged from the hydraulic pump 8, is controlled in accordance with the change in the rotational speed of the electric motor 7. The car 1 ascends according to a predetermined speed pattern.

The speed characteristics at this time follow the speed pattern A shown by the solid line in FIG. 8 by the speed control device 13. That is, the car 1 is started in response to a start command, accelerates to the rated speed fiVo, then increases at the rated speed Vo, and begins to decelerate when it reaches the position of the deceleration switch 14. Then, the robot decelerates to a certain landing speed V1, rises at this landing speed 1, and when the upper limit position is reached, the stop switch 15 is activated to stop the ascent.

Further, during the descending operation, the hydraulic pump 8 is rotated by the discharge of the weight of the car 1 from the hydraulic jack, and the descending speed of the car 1 is controlled using the electric braking of the electric I17, and power is regenerated. Also at this time, the speed control device 13 controls the electric motor 1j17 to a desired rotational speed.

(Problems to be Solved by the Invention) However, in such a conventional hydraulic elevator control device using an electric motor rotation speed control method, when the load (hydraulic pressure) or oil amount of the hydraulic elevator changes, the characteristics of the hydraulic pump 8 change. There is a problem that the running pattern of the car 1 deviates from a predetermined pattern. For example, when the car is rising, the hydraulic pump 8 generally decreases the amount of pressure oil discharged as the pressure (or oil temperature) increases, and decreases the amount of pressure oil discharged as the pressure (or oil temperature) decreases, as shown in Figure 9. Accordingly, as the pressure (or oil temperature) increases, the speed pattern of car 1 becomes pattern B shown by the broken line in Figure 8, and the pressure (or oil temperature) increases.
When the value decreases, the running pattern C becomes a dash-dotted line. and,
In the case of driving pattern B shown by the broken line, the driving time becomes longer, leading to a decrease in service, and in the case of driving pattern C shown by the dashed-dotted line, the problem arises that the riding comfort, especially when stopped, deteriorates. .

Furthermore, when descending, a phenomenon opposite to the above-mentioned phenomenon occurs when ascending.

The present invention has been made to solve these conventional problems, and provides a hydraulic elevator control that can always provide constant running characteristics by correcting the running characteristics of the hydraulic elevator using a control circuit with a simple configuration. The purpose is to provide equipment.

[Structure of the Invention] (Means for Solving the Problems) A control device for a hydraulic elevator according to the present invention includes a hydraulic pump connected to a hydraulic jack via an electromagnetic switching valve and for circulating pressure oil to the hydraulic jack; an AC motor rotatably connected to the pump, a frequency control device for controlling the power frequency for the AC Ti motor, a speed control device for giving a frequency command based on a predetermined speed pattern to the frequency control device, and the hydraulic jack. an oil temperature sensor and an oil pressure sensor for the pressure oil flowing through the system, and a pattern in which signals from these sensors are input and the frequency command from the speed control device is corrected so that the hydraulic jack can move up and down in a predetermined speed pattern. It is equipped with a generation circuit.

(Function) In the hydraulic elevator control device of the present invention, the oil pressure and extracted oil flowing into and out of the hydraulic jack are detected immediately before starting the hydraulic elevator, and the control circuit corrects a predetermined speed pattern based on the detected values. The number of rotations of the electric motor is controlled according to this corrected speed pattern, and as a result, the car can always be moved up and down in the normal speed pattern.

(Example) Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1 shows one embodiment of the present invention, and symbols 1 to 15 are seventh
It shows the common components with the conventional example shown in the figure. In this embodiment, this temperature sensor 16 is connected to the tank 10.
A hydraulic sensor 17 is provided on a hydraulic pipe 18 connecting the hydraulic jack 2 and the electromagnetic switching valve 9, each of which is connected to provide a detection signal to the speed control device 13.

This speed m control device 13 also has a temperature and oil pressure detection function and a speed pattern correction function, and has a pattern generation circuit 20 by a microcomputer as shown in FIG.

This pattern generation circuit 20 includes a CPU 21 that controls the entire microcomputer, a memory 22 that stores programs and data, a deceleration switch 14, and a stop switch 1.
5, an input gate 23 that inputs digital signals from the temperature sensor 16 and oil pressure sensor 17, and an A/D converter (ADC>24 that inputs analog signals from the temperature sensor 16 and oil pressure sensor 17 and converts them into digital signals), and a D/A converter that outputs the driving pattern. DAC (DAC) 25, and a pass line 26 connecting them.

The operation of the hydraulic elevator control device having the above configuration will be described next.

When the car 1 is stopped, the electromagnetic switching valve 9 is closed. When a driving command is issued, oil temperature sensor 16 and oil pressure sensor F
The speed pattern is corrected within the speed control device 13 based on the signal from J17, and the electric motor 7 starts rotating.

Therefore, in the frequency control device 12, the speed control device 1
The frequency of the power source 11 is controlled based on the speed pattern corrected by 3, the rotational speed of the electric tI7 is controlled, the rotational speed of the hydraulic pump 8, and therefore the discharge 1 of the hydraulic pump 8 is controlled, and the plunger 3 of the hydraulic jack 2 and The raising and lowering of the car 1 is controlled.

Here, as mentioned above, if you try to control the speed according to the same speed pattern related to oil pressure and oil temperature (as shown in Figure 8), the actual running waveform will change significantly due to changes in oil pressure and oil temperature. I will do it.

Therefore, in order to obtain a predetermined speed pattern even when the oil pressure and oil temperature change, it is necessary to generate a pattern as shown in FIG. 3. In other words, normal oil pressure,
If the oil temperature pattern is Ao, when the oil pressure and oil temperature are high, the hydraulic pump discharge is small, so pattern A1 is generated, and conversely, when the oil pressure and oil temperature are low, the hydraulic pump discharge end is large, so pattern A2 is generated. This is done so that L is generated.

Therefore, the memory 22 of the control circuit 20 in the speed control device 13 stores the oil pressure as shown in FIG.

A first table for selecting a speed pattern based on a combination of oil temperatures, and a second table for determining acceleration α, deceleration β, top pattern SI, and creep pattern S2 for each speed pattern as shown in FIG. is stored.

Next, the operation of the control circuit 20 will be explained based on the flowchart shown in FIG. 6.The CPtJ 21 inputs various starting conditions through a circuit not shown, and enters the starting routine only when predetermined starting conditions are met. (Step 8101).

When started, first, each sensor 16.17 is sent from ADC24.
Input oil temperature and oil pressure detection signals from (step 81)
02>.

Next, an address corresponding to the oil temperature and oil pressure at that time is extracted from the first table shown in FIG. 4, which is stored in advance in the memory 22 (step 8103).

Next, a plurality of data stored at the address, that is, acceleration a1, deceleration β, top pattern S+, and creep pattern S2, are extracted from the second table shown in FIG. 5, which is also stored in advance in the memory 22 (step 8104).

Using these data, the DAC 25 outputs an acceleration pattern based on the acceleration α according to a calculation formula stored in the memory 22 in advance (step 8105).

Next, when the acceleration pattern becomes equal to the top pattern S1, the top pattern SI as a constant speed pattern is maintained and outputted from the DAC 25 (step 81
06.8107).

Next, when the signal of the deceleration switch 14 of the destination floor is input from the input gate 23, the deceleration pattern based on the deceleration β is output from the DAC 25 (steps 8108 and 510).
9).

Next, when the deceleration pattern becomes equal to the creep pattern S2, the creep pattern S2 is maintained and output from the DAC 25 (steps 5110 and 5111).

Next, when a signal from the destination floor stop switch 15 is input from the input gate 23, pattern output is stopped (steps 8112 and 8113>).

In this way, the speed control device 13 can automatically select and output the optimal travel pattern by inputting the oil pressure and oil temperature at each time the elevator travels, and the frequency control device F112 is an electric motor that drives the hydraulic pump 8 according to this speed pattern! The rotational speed of the car 1EI7 is controlled, and as a result, the car 1 can travel while maintaining the actual traveling speed always in the same pattern as in normal times.

In the above embodiment, the temperature sensor 16 was provided inside the tank 10, but the temperature sensor 16 may also be provided on the hydraulic jack 2 or in the middle of the piping between the hydraulic jack 2 and the hydraulic pump 8, and the location may vary. Not particularly limited.

[Effects of the Invention] As described above, according to the present invention, even if the oil temperature and oil pressure fluctuate from the time of setting the speed pattern, the oil temperature remains constant.

The speed pattern is corrected based on the oil pressure detection signal, and the rotational speed of the motor is controlled by controlling the frequency of the power supply.
In order to control the rotation speed of the hydraulic pump and therefore the discharge amount of the hydraulic pump, when the car is raised, the rotation speed of the electric motor is On the other hand, when the oil temperature or oil pressure decreases and the discharge 1 of the hydraulic pump increases, the motor rotation speed is controlled to lower the oil temperature or oil pressure to the required level. The elevator can always run at an appropriate speed pattern without being affected by the

[Brief explanation of the drawing]

Fig. 1 is a system diagram of an embodiment of the present invention, Fig. 2 is a block diagram of a control circuit in the above embodiment, Fig. 3 is an explanatory diagram of a running pattern used in the above embodiment, and Fig. 4 is an illustration of the above embodiment. FIG. 5 is a structural diagram of the first data table in the example, and FIG. 6 is a structural diagram of the second data table in the above embodiment.
The figure is a flowchart of the operation of the control circuit in the above embodiment, Figure 7 is a system diagram of the conventional example, Figure 8 is an explanatory diagram of the running pattern of the conventional example, and Figure 9 is a characteristic diagram of the hydraulic pump.・AC induction motor 8...Hydraulic pump 9...
Electromagnetic switching valve 11... Power supply 12... Frequency control device 13... Speed control device 16... Oil pressure sensor 17... Oil pressure sensor 20.
...Pattern generation circuit 21...CPU 22...Memory 23.
...Input gate 24...A/D converter (ADC> 25...D/A converter (DAC) 26...Bus line Figure 5 Figure 2 Prefecture 6 Figure Time 8 Prisoner Dog

Claims (1)

[Claims] A hydraulic pump connected to the hydraulic jack via an electromagnetic switching valve and distributing pressure oil to the hydraulic jack, an AC motor rotatably connected to the hydraulic pump, and a frequency control device controlling a power frequency for the AC motor. A speed control device that gives a frequency command based on a predetermined speed pattern to the frequency control device, an oil temperature sensor and a hydraulic pressure sensor for the pressure oil flowing through the hydraulic jack, and signals from these sensors are input, and the A control device for a hydraulic elevator, comprising a pattern generation circuit that corrects a frequency command from the speed control device so that the hydraulic jack can move up and down in a predetermined speed pattern.