JPH07100573B2 - Control device for hydraulic elevator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a control device for a hydraulic elevator.

(Prior Art) Generally, a hydraulic elevator adopts a flow rate control method using a flow rate control valve. In this control method, the motor is rotated at a constant speed when rising, the constant discharge amount of oil from the hydraulic pump is returned to the tank, and when the start command is issued, the amount returned to the tank is adjusted by the flow control valve. It controls the speed of the car. Further, when descending, the flow rate control valve adjusts the amount of oil that the oil in the cylinder circulates to the tank by its own weight to control the car speed. However, in this method, extra oil is circulated when rising, and potential energy is consumed for heat generation of oil when descending, so not only energy loss is large, but also the oil temperature rises significantly.

On the other hand, a so-called electric motor rotational speed control method has been devised in recent years, in which the voltage and frequency are changed to control the rotational speed of the induction motor over a wide range in accordance with the technological progress of semiconductors. In this system, a constant discharge hydraulic pump is used, and the discharge amount of the pump is variably controlled by changing the rotation speed of the electric motor.

FIG. 3 shows the configuration of a hydraulic elevator that employs the above-described electric motor speed control method. In FIG. 3, 1 is an elevator car, 2 is a hydraulic jack containing a plunger 3, 4 is a sheave attached to the upper part of the plunger 3, 5 is a rope hung on the sheave 4, and one end of this rope 5 is It is attached to the car 1 and the other end is attached to the foundation 6, respectively. 7 is an AC induction motor directly connected to the hydraulic pump 8;
Is a first electromagnetic switching valve arranged between the hydraulic jack 2 and the hydraulic pump 8, 10 is a tank, 11 is a power source, 12 is connected to the electric motor 7 and the power source 11, and the voltage and frequency are controlled by the semiconductor. The power conversion device 13 is a speed control device that controls the power conversion device 12.

Next, the operation of the hydraulic elevator will be described. During the ascending operation, the electric motor 7 rotates according to the operation command. At this time, the frequency of the power supply 11 is controlled by the speed control device 13, the rotation speed of the electric motor 7 is controlled, the rotation speed of the hydraulic pump 8, and thus the discharge amount of the hydraulic pump 8 is controlled, and the car 1 is driven at a predetermined speed. Rise according to the pattern.

With respect to its speed characteristic, the speed control device 13 travels along the speed pattern shown in FIG. That is,
In response to the start command, the car 1 is started and accelerated, rises at the rated speed, and reaches the position of the deceleration switch 15.
When the car 15 operates, the car 1 starts to decelerate, and then decelerates to a constant landing speed, and when it rises at this speed and reaches the upper limit position, the stop switch 16 is turned off to stop. When the vehicle is descending, the solenoid 14 is excited by the operation command, the hydraulic circuit opens, and the hydraulic pressure is discharged from the hydraulic jack 2 by the weight of the car 1 to rotate the hydraulic pump 8 to control the power generation of the electric motor 7. By utilizing this, the descent speed of the car 1 is controlled and the power is regenerated. Also at this time, the speed control device 13 controls the electric motor 7 to a required rotation speed.

However, the hydraulic elevator of such a control system has the following problems. That is, (1) When the electric motor 7 is in an uncontrolled state due to a power failure or the like during descending traveling, braking is no longer effective, and the electric motor 7 and the hydraulic pump 8 continue to rotate by the pressure oil from the hydraulic jack 2 and gradually move the circuit. When the discharge amount by the inertia of the electric motor 7 and the hydraulic pump 8 becomes larger than the flow rate due to the opening degree of the electromagnetic switching valve 9 which is closed, a negative pressure is generated between the hydraulic pump 8 and the electromagnetic switching valve 9, and an abnormal sound is generated. , Damage to the equipment,
There may be a safety issue. Further, even if the solenoid 14 of the solenoid operated directional control valve 9 is demagnetized due to a stop or the like, there is a delay time of about 0.3 to 1 second until the solenoid 9 is closed due to the characteristic of the valve 9.
Depending on the conditions such as the load, the vehicle may overspeed, the riding comfort may deteriorate, and a safety problem may occur.

(2) While the car is stopped, a space is created between the electromagnetic switching valve 9 and the hydraulic pump 8 due to oil leakage, and when the electromagnetic switching valve 9 opens during the descent operation, the hydraulic pressure from the hydraulic jack 2 is thereby released. 9 suddenly flows into the space between the hydraulic pump 8 and the hydraulic pump 8.
The speed increases as the number of revolutions increases, and eventually becomes constant. In this way, when the descent is started, the descent is suddenly lowered, which gives passengers anxiety.

Conventionally, as for the above (1), as shown in FIG.
Connecting device 17 between electric motor 7 and hydraulic pump 8 and braking device
Equipped with 18, the electric motor 7 and the hydraulic pump 8 are provided when the regular electric power supply to the electric motor 7 is cut off due to a power failure or the like while the vehicle is descending.
A braking force is applied to the pipe by a frictional force between the connecting device 17 and the braking device 18, and the generation and acceleration of negative pressure in the pipeline are prevented. Regarding (2) above, the hydraulic pump 8 at the start of the descending operation is used.
After rotating at a very low speed to compensate for the amount of oil leakage, normal descent operation is started.

Etc. are being taken.

(Problems to be Solved by the Invention) However, in the hydraulic elevator having the above configuration,
It had the following drawbacks.

(1) The brake device 18 is complicated and requires a large installation space. Further, since the connecting device 17 cannot use the connecting device which is normally used in order to produce a predetermined braking force, and it is a special one, it becomes expensive and it is difficult to adjust the braking force. Depending on the conditions,
Even after the electromagnetic switching valve 9 is completely closed, the hydraulic pump 8 may rotate due to inertia, and the hydraulic pump 8 may seize.

(2) Since the hydraulic pump 8 is rotated at a slight speed before the start, it takes time from the issuing of the operation command until the car 1 starts traveling, and the service to passengers is deteriorated.

An object of the present invention is to provide a hydraulic elevator control device capable of performing smooth start-up, eliminating the seizure of the hydraulic pump, simplifying the device, and reducing the installation space.

[Structure of Invention]

(Means for Solving the Problems) The present invention provides a hydraulic jack that raises and lowers a plunger connected to a car, and an electric motor controls the supply of oil from the oil tank to the hydraulic jack when the car rises. However, when the car descends, a hydraulic pump for returning the oil of the hydraulic jack to the oil tank and a pipeline connecting the hydraulic jack and the hydraulic pump are provided, and an operation command for ascending or descending to the car is provided. Is excited to open a conduit connecting the hydraulic jack and the hydraulic pump, and a first electromagnetic switching valve that demagnetizes by a stop command to the car, and a conduit connecting the hydraulic pump and the oil tank. Is provided in the vehicle and is excited when an operation command for ascending or descending to the car is issued, opens a pipe line connecting the hydraulic pump and the oil tank, and demagnetizes by a stop command to the car. An electromagnetic switching valve, a pipe connecting the first electromagnetic switching valve and the hydraulic pump, and a bypass pipe for communicating the second electromagnetic switching valve, and a bypass pipe provided in the bypass pipe for connecting the second electromagnetic valve. A check valve for blocking the inflow of oil to the switching valve side;
The electromagnetic switching valve is configured to allow the oil flowing from the hydraulic pump to the oil tank side to flow to the bypass pipe when demagnetized.

(Operation) When the car rises, the hydraulic pump supplies the oil in the oil tank obtained through the second electromagnetic switching valve to the hydraulic jack through the first electromagnetic switching valve. When the car descends, the oil of the hydraulic jack is transferred to the first electric switching valve, the hydraulic pump and the second electric switching valve.
It is returned to the oil tank via the electromagnetic switching valve. The bypass pipe circulates the oil from the hydraulic pump to the pipe connecting the hydraulic pump and the first electromagnetic switching valve via the second electromagnetic switching valve when the elevator is stopped.

(Example) An example of the present invention will be described with reference to the drawings. First
The figure shows a block diagram of a control device for a hydraulic elevator according to an embodiment of the present invention. In FIG. 1, those parts which are the same as those shown in FIG. 3 are designated by the same reference numerals.

In this embodiment, a second electromagnetic switching valve 19 is provided between the hydraulic pump 8 and the tank 10, and the electromagnetic switching valve 19 and the pipe 20 between the hydraulic pump 8 and the electromagnetic switching valve 9 are bypass pipes. Road 21
, The check valve 22 is provided on the way of the bypass pipe 21, and when the car 1 stops while traveling downward, the oil circulating from the hydraulic jack 2 to the tank 10 is circulated to the hydraulic jack 2 side of the hydraulic pump 8. It was made possible. Reference numeral 19 is an electromagnetic switching valve provided between the hydraulic pump 8 and the tank 10, 21 is a pipe 20 between the electromagnetic switching valve 9 of the hydraulic pump 8 and the electromagnetic switching valve 19 provided on the tank 10 side. A check valve 22 is provided on the bypass line 21 along the bypass line 21. Further, in the present embodiment, the brake device 18 is unnecessary.

The second shows an example of an exciting circuit of the solenoid 23 of the electromagnetic switching valve 19.

XU and XD are normally open contacts of a relay (not shown) that is excited by rising and falling commands, MR is a contactor and MR1 is its normally open contact, and 23 is a solenoid. Next, the operation of this embodiment based on the above configuration will be described. First, the solenoid 23 of the electromagnetic switching valve 19 will be described. Normally open contacts XU, XD of a relay (not shown) that is excited by up / down commands
Causes the coil of the contactor MR to be excited by closing the XU or XD contact with the operation command. When the contactor MR is excited, the normally open contact MR1 added in series to the solenoid 23 is closed and the solenoid 23 is excited.

When the car 1 is stopped, the electromagnetic switching valves 9 and 19 are in the illustrated state. That is, the electromagnetic switching valve 9 is in a closed state, and the electromagnetic switching valve 19 is in a state in which the pipeline of the hydraulic pump 8 on the tank 10 side is connected to the bypass pipeline 21. At this time, when a rising operation command is issued, the solenoid 23 of the electromagnetic switching valve 19 is excited and the circuit between the hydraulic pump 8 and the tank 10 starts to move in the opening direction, and at the same time, the electric motor 7 and the hydraulic pump 8 start to rotate. The hydraulic pressure is sent to the hydraulic jack 2 through the electromagnetic switching valve 9. At this time, the speed control device 13
The voltage and frequency of the power supply 11 are controlled by the electric motor 7
The rotation speed of the hydraulic pump 8 is controlled, the rotational speed of the hydraulic pump 8 and hence the discharge amount of the hydraulic pump 8 is controlled, and the car 1 is
It rises according to the predetermined speed pattern in the figure. Car 1
However, when the position of the deceleration switch 15 is reached and the switch 15 operates, the car 1 starts decelerating. When it further rises and reaches the upper limit position, and the stop switch 16 operates, the hydraulic pump 8 stops with no operating command for raising, and the solenoid 23 of the electromagnetic switching valve 19 is demagnetized at the same time, and the tank of the hydraulic pump 8 is demagnetized.
The circuit on the 10th side is connected to the bypass line 21 and the car 1 stops. Further, when a descending operation command is issued, the solenoids 14 and 23 of the electromagnetic switching valves 9 and 19 are excited, and the hydraulic jack 2 and
The circuit between the tanks 10 is open, and due to the weight of the car 1,
By discharging the hydraulic pressure from the hydraulic jack 2, the hydraulic pump 8
Is rotated to utilize the dynamic braking of the electric motor 7 to control the descending speed of the car 1 and regenerate power. When the car 1 turns off the deceleration switch, it starts decelerating. Further, when the lower limit position is reached, the stop switch is turned off, and the hydraulic pump 8 stops. At the same time, there is no lowering operation command and the solenoids 14 and 23 of the electromagnetic switching valves 9 and 19 are demagnetized, and the hydraulic pump 8 and the hydraulic jack 2 are connected. The circuit of is closed. Further, the tank 10 side of the hydraulic pump 8 is connected to the bypass pipe line 21,
Cage 1 stops.

Next, a case where the electric motor 7 is in an uncontrolled state due to a power failure or the like during the downward traveling will be described.

When the electric motor 7 is in an uncontrolled state due to a power outage or the like during descending traveling, braking is lost and the electric motor 7 and the hydraulic pump 8 are
Continues to rotate due to the pressure oil from the hydraulic jack 2,
Simultaneously with the power failure, the solenoids 14 and 23 of the electromagnetic switching valves 9 and 19 are demagnetized, the electromagnetic switching valve 9 starts to gradually close the circuit, and the electromagnetic switching valve 19 gradually releases the pressure oil flowing from the hydraulic pump 8 to the tank 10. Then, it starts flowing toward the bypass line 21. Therefore, the discharge amount due to the inertia of the electric motor 7 and the hydraulic pump 8 becomes larger than the flow rate depending on the opening degree of the electromagnetic switching valve 9, and the pressure between the hydraulic pump 8 and the electromagnetic switching valve 9 tends to become a negative pressure. Since the shortage is replenished through the bypass line 21, the negative pressure is not obtained as a result. Therefore, a negative pressure is not created between the hydraulic pump 8 and the electromagnetic switching valve 9, so that occurrence of abnormal noise, damage to equipment, and excessive speed are all eliminated. When the electromagnetic switching valve 9 is completely closed, the car 1 is stopped. At that time, since the electromagnetic switching valve 19 is also completely switched, even if the hydraulic pump 8 is still rotating due to inertia, the entire discharge amount is supplied through the bypass pipe line 21. It will not happen and the hydraulic pump 8 will not burn.

Further, since the electromagnetic switching valve 19 completely shuts off the connection between the hydraulic pump and the tank 10, there is no oil leakage from the hydraulic pump 8.

〔The invention's effect〕

Due to the above, even if the electric motor goes into an uncontrolled state due to a power outage or the like while descending, it prevents abnormal noise, damage to the equipment, and overspeed, and also prevents descending due to oil leakage from the hydraulic pump. It is possible to prevent a sudden drop at the start and the following effects are provided.

(1) The device is simple, the installation space is small, and the cost is low.

(2) The seizure of the hydraulic pump can be prevented.

(3) Since the descending traveling is started at the same time when the driving command is issued, the smooth starting can be performed and the service for passengers can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a control device for a hydraulic elevator according to an embodiment of the present invention, FIG. 2 is an excitation circuit diagram of a solenoid of an electromagnetic switching valve according to an embodiment shown in FIG. 1, and FIG. FIG. 4 is a configuration diagram of a conventional hydraulic elevator control device, and FIG. 4 is a travel pattern diagram in the hydraulic elevator. 2 ... hydraulic jack, 7 ... AC induction motor 8 ... hydraulic pump, 9 ... first electromagnetic switching valve, 19 ... second electromagnetic switching valve 11 ... power supply, 12 ... frequency control device 13 ... … Speed control device, 17 …… Coupling device 18 …… Brake device, 21 …… Bypass line 22 …… Check valve, 14,23 …… Solenoid

Claims (1)

[Claims] Claims: 1. A hydraulic jack for raising and lowering a plunger connected to a car, and an electric motor that controls oil to supply oil from the oil tank to the hydraulic jack when the car rises, and when the car descends. Is provided in a hydraulic pump that returns the oil of the hydraulic jack to the oil tank, and a pipe line that connects the hydraulic jack and the hydraulic pump, and is excited when an ascending or descending operation command is issued to the car, and A first electromagnetic switching valve that opens a pipe line connecting the hydraulic jack and the hydraulic pump and demagnetizes by a stop command to the car, and a pipe line that connects the hydraulic pump and the oil tank to each other to raise the car. Alternatively, a second electromagnetic switching valve that is excited when a descending operation command is issued, opens a pipe line connecting the hydraulic pump and the oil tank, and demagnetizes by a stop command to the car; A bypass pipe for connecting the electromagnetic switching valve and the hydraulic pump to the second electromagnetic switching valve, and a bypass pipe provided in the bypass pipe to prevent the oil from flowing into the second electromagnetic switching valve. And a check valve for blocking, wherein the second electromagnetic switching valve allows the oil flowing from the hydraulic pump to the oil tank side to communicate with the bypass pipe when demagnetized. apparatus.