JPS63235275A - Controller for hydraulic elevator - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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) Hydraulic elevators generally employ a flow control method using a flow control valve. This control method.

When ascending, the electric motor rotates at a constant speed and a fixed amount of oil discharged from the hydraulic pump is returned to the tank.When a start command is issued, the speed of the car is controlled by adjusting the amount returned to the tank with a flow control valve. are doing. Furthermore, when descending, the car's weight is used to adjust the amount of oil in the cylinder that flows back into the tank using a flow control valve, thereby controlling the car's speed. However, in this method, excess oil is circulated during ascent, and potential energy is consumed to heat the oil when descending, resulting in not only a large energy loss but also a significant rise in oil temperature.

In contrast, in recent years, with advances in semiconductor technology, so-called motor rotation speed control systems have been devised in which the rotation speed of an induction motor is controlled over a wide range by varying the voltage and frequency. This uses a constant discharge type hydraulic pump and variably controls the discharge amount of the pump by changing the rotational speed of the electric motor.

In FIG. 3, the configuration of a hydraulic elevator employing the above-mentioned motor rotation speed control method is shown in FIG.

1 is an elevator car, 2 is a hydraulic jack with a built-in plunger 3, 4 is a sheave attached to the top of the plunger 3, 5 is a rope that is hung over the sheave 4, and one end of this rope 5 is attached to the elevator car and the other. The ends are each attached to the foundation 6. 7 is an AC induction motor directly connected to the hydraulic pump 8, and 9 is an AC induction motor.

An electromagnetic switching valve is arranged between the hydraulic jack 2 and the hydraulic pump 8, 1G is a tank, 11 is a power supply, 12 is an electric motor 7
and a power converter 13 that is connected to the power source 11 and controls voltage and frequency using a semiconductor; 13 is a speed controller that controls the power converter 12;

Next, the operation of the hydraulic elevator will be described. During upward operation, the electric motor 7 rotates in accordance with the operation command. At this time, the frequency of the power source 11 is controlled by the speed control device 13, the rotational speed of the electric motor 7 is controlled, and the hydraulic pump 8 is controlled.
The rotational speed of the hydraulic pump 8 and therefore the discharge amount of the hydraulic pump 8 are controlled, and the ride and heel 1 are increased according to a predetermined speed pattern.

As for its speed characteristics, it is a speed control device! 13, the vehicle travels along the speed pattern shown in FIG. That is, in response to the start command, the 1st seat and 1 are started, accelerated, ascend at the rated speed, and reach the position of the deceleration switch 15, and when this switch 15 is activated, the 1st seat and 1 begin to decelerate, and then decelerate to a constant landing speed. When it ascends at this speed and reaches the upper limit position, the stop switch 16 is turned off and it stops.

In addition, during descending operation, the solenoid 14 is energized by the operation command, the hydraulic circuit is opened, and the hydraulic pump 8 is rotated by discharging pressure oil from the hydraulic jack 2 due to the weight of one passenger and one, and the dynamic braking of the electric motor 7 is performed. 1 using
It controls the descending speed of the car and 1 and regenerates power. At this time as well, the speed control device 13 controls the electric motor 7 to a required rotational speed.

However, hydraulic elevators using this type of control system have the following problems. Namely.

■ If the electric motor 7 goes into an uncontrolled state due to a power outage, etc. while descending, the braking will no longer work, and the electric motor 7 and hydraulic pump 8 will continue to rotate due to pressure oil from the hydraulic jack 2, and the electromagnetic circuit will gradually close the circuit. When the amount of discharge due to 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 switching valve 9, a negative pressure is created between the hydraulic pump 8 and the electromagnetic switching valve 9.
Abnormal noise may be generated and equipment may be damaged, which may pose a safety problem. Furthermore, even if the solenoid 14 of the electromagnetic switching valve 9 is demagnetized due to a stop, etc., there is a delay time of about 0.3 to 1 second before it starts closing due to the characteristics of the valve 9, so it may overspeed depending on the load and other conditions. This may make the ride uncomfortable and may pose a safety problem.

■ During stoppage, 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 descending operation, pressure oil from the hydraulic jack 2 flows into the electromagnetic switching valve 9. Since it rapidly flows into the space between the hydraulic pump 8 and the hydraulic pump 8, it rapidly descends at the start, then increases in speed as the rotational speed of the hydraulic pump 8 increases, and eventually reaches a constant speed. In this way, at the start of the descent, the vehicle descends rapidly, giving the nine passengers a sense of anxiety.

Conventionally, regarding the above-mentioned ω, as shown in FIG.
8, the electric motor 7 and the hydraulic pump 8 are equipped with a
Connecting device f17 and brake device! Provides braking force by frictional force with 18 to prevent generation of negative pressure in the pipeline and overspeed, and
Regarding (2) above, the hydraulic pump 8 is rotated at a slow speed at the start of the descending operation to compensate for the amount of oil leakage, and then the regular descending operation begins.

We are taking measures such as:

(Problems to be solved by the invention) However, in the hydraulic elevator with the above configuration,
It had the following drawbacks.

- The brake device 18 is complicated, and its large installation requires space. In addition, the coupling device 17 cannot use a commonly used coupling device 9 to produce a predetermined braking force, and is a special device, which makes it expensive and difficult to adjust the braking force. Depending on the conditions,
Even after the electromagnetic switching valve 9 is completely closed, the hydraulic pump 8 continues to rotate due to inertia, and the hydraulic pump 8 may seize.

■ The hydraulic pump 8 is rotated at a slow speed before starting, so
It takes a long time from when a driving command is issued until the car and the car start running, resulting in poor service to passengers.

An object of the present invention is to provide a control device for a hydraulic elevator that can perform smooth startup, eliminate seizing of the hydraulic pump, simplify the device, and reduce installation space. .

[Structure of the invention]

(Means for Solving Problems) The present invention includes a hydraulic cylinder that raises and lowers a plunger connected to a car, and a hydraulic cylinder that supplies oil from an oil tank to the hydraulic cylinder when the car goes up, and when the car goes down. A hydraulic pump is installed between the hydraulic cylinder and the hydraulic pump to return the oil from the hydraulic cylinder to the oil tank, and when the car is raised, the oil flows from the hydraulic pump to the hydraulic cylinder.
A first switching valve is provided between the hydraulic pump and the oil tank and a first switching valve that allows the oil in the hydraulic cylinder to flow from the hydraulic cylinder to the hydraulic pump when the car is lowered, and the oil in the oil tank to flow when the car moves up. a second switching valve that allows oil to flow to the hydraulic pump, and from the hydraulic pump to the oil tank when the car is lowered;
A bypass pipe is provided that allows oil to flow from the hydraulic pump to the connecting portion between the hydraulic pump and the first switching valve via the second switching valve when the elevator is stopped.

(Function) When the car is raised, the hydraulic pump supplies oil from the oil tank obtained through the second switching valve to the hydraulic cylinder through the first switching valve. Furthermore, when the car is lowered, the oil in the oil cylinder is returned to the oil tank via the first switching valve, the hydraulic pump, and the second switching valve. The bypass pipe allows oil to flow from the hydraulic pump through the second switching valve to the connection between the hydraulic pump and the first switching valve when the elevator is stopped.

(Example) An example based on the present invention will be described using the drawings. 1st
The figure shows a configuration diagram of a control device for a hydraulic elevator according to an embodiment of the present invention. In FIG. 1, the same components as those shown in FIG. 3 are given the same reference numerals.

In this embodiment, an electromagnetic switching valve 19 is provided between the hydraulic pump 8 and the tank 10.

Hydraulic pump8. The piping 20 between the electromagnetic switching valve 9 and the piping 20 is connected by a bypass piping 21, and a check valve 22 is provided in the middle of the bypass piping 21, and when the vehicle travels downward and the first vehicle stops when the first vehicle is on board,
The oil circulating from the hydraulic jack 2 to the tank 10 can be circulated to the hydraulic jack 2 side of the hydraulic pump 8. 19 is an electromagnetic switching valve provided between the hydraulic pump 8 and the tank 10; 19 is an electromagnetic switching valve 19 provided on the side of the tank 10 and the piping 20 between the hydraulic pump 8 and the electromagnetic switching valve 9;
A check valve 22 is provided in the middle of the bypass pipe 21. Further, in this embodiment, the brake device 18 is not necessary.

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

XU and XD are normally open contacts of relays (not shown) that are excited by the ascending and descending commands, respectively, and MR is the contactor and MHI.
23 is a normally open contact, and 23 is a solenoid.The operation of this embodiment based on the above-described configuration will be explained below. First, the solenoid 23 of the electromagnetic switching valve 19 will be explained.

Normally open contacts XU and XD of a relay (not shown) are energized by a rise and fall command, and the contacts XU or XD close together with the operation command to energize the coil of the contactor MR. When the contactor MR is energized, the normally open contact MHI added in series to the solenoid 23 is closed, and the solenoid 23 is energized.

When the carriage and 1 are stopped, the solenoid switching valve 9.19
is the state shown. 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 pipe line on the side of the tank 10 of the hydraulic pump is connected to the bypass pipe line 21. At this time, when an upward operation command is issued, the electromagnetic switching valve 19
Solenoid 23 is energized, and hydraulic pump 8 and tank 1
At the same time as the circuit between 0 and 0 begins to move in the open direction, the electric motor 7 and hydraulic pump 8 begin to rotate, and pressure oil passes through the electromagnetic switching valve 9.

It is fed into the hydraulic jack 2. At this time, the speed control device 13 controls the voltage and frequency of the power source 11, the rotational speed of the electric motor 7, the rotational speed of the hydraulic pump 8, and therefore the discharge amount of the hydraulic pump 8, and the , 0 and 1, which are rising according to the predetermined speed pattern shown in FIG. 4, reach the position of the deceleration switch 15, and when the switch 15 is operated, the 0 and 1 cars begin to decelerate. When the hydraulic pump 8 further rises and reaches the upper limit position, and the stop switch 16 is operated, the hydraulic pump 8 is stopped due to the lack of the rising operation command.

At the same time, the solenoid 23 of the electromagnetic switching valve 19 is demagnetized, the circuit on the tank 10 side of the hydraulic pump 8 is connected to the bypass pipe 21, and the ride and heel 1 are stopped. In addition, when a descending operation command is issued, the solenoid 14 of the electromagnetic switching valve 9, 19 is activated.
23 is energized, and the hydraulic jack 2. The circuit between the tank 10 is opened, and the hydraulic pump 8 is rotated by the discharge of pressure oil from the hydraulic jack 2 due to the weight of the rider and the rider 1, and the descending speed of the rider and the rider 1 is controlled using the dynamic braking of the electric motor 7. When the first driver, which controls and regenerates power, turns off the deceleration switch, it begins to decelerate. Furthermore, when the lower limit position is reached, the stop switch is turned off, and at the same time the hydraulic pump 8 stops, the lowering operation command disappears and the electromagnetic switching valves 9, 1
9 solenoid 14.23 is demagnetized and hydraulic pump 8. The circuit between the hydraulic jacks 2 is closed.

Furthermore, a bypass pipe 2 is connected between the tank 10 of the hydraulic pump 8.
1, and the ride and 1 stop.

Next, a case will be described in which the electric motor 7 becomes uncontrolled due to a power outage or the like during descending travel.

During descending travel, if the electric motor 7 becomes uncontrolled due to a power outage, etc., braking will no longer work, and the electric motor 7 and hydraulic pump 8 will continue to rotate due to pressure oil from the hydraulic jack 2, but at the same time as the power outage, the electromagnetic switching valve 9 °19 solenoid 14.2
3 is demagnetized, the electromagnetic switching valve 9 begins to gradually close the circuit,
The electromagnetic switching valve 19 causes the pressure oil that was flowing from the hydraulic pump 8 to the tank 10 to gradually start flowing toward the bypass pipe line 21.

Therefore, the amount of discharge due to the inertia of the electric motor 7 and hydraulic pump 8 becomes larger than the flow rate due to 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 negative. , the shortage is replenished through the bypass pipe line 21, and as a result, the pressure does not become negative. Therefore, since there is no negative pressure between the hydraulic pump 8 and the electromagnetic switching valve 9, abnormal noises, equipment damage, and overspeeding are all eliminated. Further, when the electromagnetic switching valve 9 is completely closed, the ride heel 1 stops. At that time, the electromagnetic switching valve 19 has also been completely switched.

Even if the hydraulic pump 8 is still rotating due to inertia, the entire discharge amount is supplied through the bypass pipe 21, so
Negative pressure will not occur and the hydraulic pump 8 will not burn out.

In addition, the hydraulic pump and tank 10 are controlled by the electromagnetic switching valve 19.
Since the gap is completely blocked, oil leakage from the hydraulic pump 8 is also eliminated.

〔Effect of the invention〕

As described above, even if the electric motor becomes uncontrolled due to a power outage, etc. during descending travel, damage to equipment that generates abnormal noises and overspeeding can be prevented, and it is also possible to prevent descending travel caused by oil leakage from hydraulic pumps, etc. In addition to being able to prevent a sudden drop at the start, there are the following effects.

■ The device is simpler, requires less space to install, and is cheaper.

■ Prevents seizing of the hydraulic pump.

- Since the vehicle starts descending as soon as a driving command is issued, smooth start-up can be achieved and service to passengers can be improved.

[Brief explanation of the drawing]

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. FIG. 4 is a block diagram of a conventional hydraulic elevator control device. FIG. 4 shows a running pattern diagram of a hydraulic elevator. 2...Hydraulic jack 7...AC induction motor 8...Hydraulic pump 9,19...
Solenoid switching valve 11...Power supply 12.
...Frequency control device 13...Speed control device! ! 17...
・Connection device 18...Brake device 21・
... Bypass pipe line 22 ... Check valve
14,23... Solenoid agent Patent attorney Nori Chika
Ken Yudo Hirofumi Mitsumata No. 1 Figure 2 Figure □Darkness Figure 4 Figure 3

Claims (1)

[Scope of Claims] A hydraulic cylinder that raises and lowers a plunger connected to the car; when the car is raised, oil from an oil tank is supplied to the hydraulic cylinder; when the car is lowered, oil from the oil tank is supplied to the hydraulic cylinder; when the car is lowered, the hydraulic cylinder is supplied with oil from an oil tank; a hydraulic pump that returns oil to the oil tank; and a hydraulic pump provided between the hydraulic cylinder and the hydraulic pump,
a first switching valve that allows oil to flow from the hydraulic pump toward the hydraulic cylinder when the car is raised, and from the hydraulic cylinder to the hydraulic pump when the car is lowered; Provided between the hydraulic pump and the oil tank, when the car is raised, oil in the oil tank flows to the hydraulic pump, and when the car is lowered, oil flows from the hydraulic pump to the oil tank. A hydraulic elevator comprising: a second switching valve; and a bypass pipe that allows oil to flow from the hydraulic pump to the connection between the hydraulic pump and the first switching valve via the second switching valve when the elevator is stopped. Control device.