JPH1036040A - Hydraulic elevator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the opening of a main control valve, and prevent the lowering of a car when the abnormality such as a failure of the second control valve is generated, by installing a means which is opened and closed by the pressure of an oil chamber on the pump side, in series with the second control valve connected to the oil chambers on the pump side and the rear face side. SOLUTION: A pressure control valve 20 is installed between an electromagnetic pilot valve 8 of the first control valve, and an electromagnetic pilot valve 9 of the second control valve. The hydraulic oil tends to flow to the oil chamber 7c side through the pressure control valve 20 and the electromagnetic pilot valve 9, when the electromagnetic pilot valve 9 can not be closed, but the opening of the main control valve 7 is delayed because of the resistance of a check valve 10 or the like. On the other hand, the pressure control valve 20 is closed without hardly delayed, by the lowering of the pressure on the oil chamber 7c side, the hydraulic oil of the oil chamber 7d does not flow, and the main control valve 7 is closed. The main control valve 7 is not opened, because the pressure control valve 20 is closed, even when the electromagnetic pilot valve 9 is erroneously excited when the pressure at the oil chamber 7c side is not raised. Thereby the lowering of the car 2 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic elevator, and more particularly to a hydraulic elevator in which a motor is controlled by inverter control or the like to control a discharge amount of a hydraulic pump driven by the motor.

[0002]

2. Description of the Related Art In a conventional hydraulic elevator, if a power failure occurs during traveling of the elevator, the car may cause a free run. This phenomenon occurs when the speed of the elevator is low during the descending operation, and does not occur during the high-speed operation of the descending operation, the acceleration, and the ascent operation. This is due to the fact that during the descent operation, the main control valve is fully opened and the hydraulic pump is controlled to control the flow rate of the hydraulic oil. For this reason, if a power failure occurs during low-speed operation, the motor stops, while the main control valve is fully open, so the flow rate of hydraulic oil increases rapidly, the car enters a free-run state, and then the main control valve As the car closes, the car decelerates and stops when the main control valve closes.

As a prior art for preventing this free run, there is Japanese Patent Application No. 8-160902. In this prior art, the opening degree of the main control valve is automatically changed depending on the oil pressure in each oil chamber constituting the main control valve and the flow rate and direction of the working oil flowing in the main control valve. This prior art will be described with reference to FIG. FIG. 2 is a schematic diagram showing the entire configuration of the hydraulic elevator.

In FIG. 1, reference numeral 1 denotes a hydraulic jack for raising and lowering the car 2; 3, a control unit for driving a hydraulic pump 5 by controlling an electric motor 4; and 6, a tank. Reference numeral 7 denotes a main control valve, which is a hydraulic jack 1 having a valve body 7a and hydraulic piping.
, A pump-side oil chamber 7c connected to the hydraulic pump 5, a rear-side oil chamber 7d disposed on the rear side of the valve body 7a, and a compression spring 7e.

Reference numeral 8 denotes a jack-side oil chamber 7b and a rear-side oil chamber 7d.
An electromagnetic pilot valve, which is a first control valve disposed therebetween, 8
a and 8b are solenoid coils, 9 is a check valve 1
The other is an electromagnetic pilot valve, which is a second control valve connected to the pump-side oil chamber 7c through the backside oil chamber 7d through 0, 9a is a solenoid coil, and 11 is a throttle arranged in parallel with the electromagnetic pilot valve 8. . In addition, each solenoid coil 8
a to 9b are operated by the operation start and stop signals of the car 2 supplied from the control unit 3.

Next, the operation of this prior art will be described. First, the case of ascending operation will be described. In response to a command from the control unit 3, the electric motor 4 starts rotating in the ascending operation direction.
The hydraulic pump 5 connected thereto is driven to increase the pressure in the oil chamber 7c. Further, the solenoid coil 8b is excited to open the electromagnetic pilot valve 8, and equalize the pressures of the oil chambers 7b and 7d. Therefore, when the valve opening force due to the pressure in the oil chambers 7c and 7b exceeds the pressure in the oil chamber 7d and the valve closing force due to the spring 7e, the valve element 7a starts to open and the car 2 starts to rise.

The flow rate of the hydraulic oil flowing through the main control valve 7 increases with an increase in the rotation speed of the electric motor 4, and the opening degree of the main control valve 7 (the opening of the valve body 7a) increases with the increase in the flow rate. The movement amount) increases, and the car 2 accelerates. When the car 2 runs at the rated speed and reaches the deceleration start point of the destination floor, the rotation speed of the electric motor 4 starts to decrease, the flow rate of the hydraulic oil in the main control valve 7 decreases, and the The opening decreases. Therefore, when the car 2 starts decelerating and lands on the destination floor, the flow rate of the hydraulic oil in the main control valve 7 becomes zero, the main control valve 7 closes, and the electric motor 4 stops. The electromagnetic pilot valve 8 keeps its position until the solenoid coil 8a is excited.

As described above, during the ascending operation, the main control valve 7
Is increased or decreased in accordance with the flow rate of the working oil, so that the opening of the main control valve 7 is minimized. Therefore, even if a power failure occurs during the ascending operation, the main control valve 7 closes promptly as the flow rate of the hydraulic oil in the main control valve 7 becomes zero, so that the hydraulic oil flows backward and the car 2 Never free-run.

Next, the case of the descent operation will be described. Control unit 3
, The motor 4 first rotates in the ascending operation direction to prevent the start-up shock of the car 2, and the oil chamber 7 c
And the pressure in the pipe connected to the oil chamber 7c is increased to a predetermined pressure. Then, the solenoid coils 8a and 9a are excited, and the electric motor 4 is rotated in the descending operation direction. As a result, the pressure in the oil chambers 7c and 7d starts to decrease, and the oil chamber 7c
When the valve opening force due to the pressure in the oil chamber 7b exceeds the pressure in the oil chamber 7d and the valve closing force due to the spring 7e, the valve element 7a starts to open,
Car 2 starts descending.

When the main control valve 7 starts to open, the hydraulic oil in the hydraulic jack 1 is pushed out by the weight of the car 2 and is discharged from the hydraulic pump 5 to the tank 6 through the main control valve 7. The opening of the main control valve 7 also increases with an increase in the flow rate of the working oil in the main control valve 7. At this time, the electric motor 4 drives the hydraulic pump 5 according to a signal from the control unit 3 to control the flow rate of the hydraulic oil to accelerate the lowering of the car 2.

When the car 2 travels at the rated speed and reaches the deceleration start point on the destination floor, the rotation speed of the electric motor 4 starts to decrease,
The flow rate of the working oil in the main control valve 7 decreases, and the opening degree of the main control valve 7 decreases. Therefore, when the car 2 starts to decelerate and lands on the destination floor, the flow rate of the hydraulic oil in the main control valve 7 becomes zero, the main control valve 7 closes, the electric motor 4 stops, and the solenoid coil 8a and 9a are de-energized. As described above, even during the lowering operation, the opening of the main control valve 7 increases and decreases in accordance with the flow rate of the working oil, and is the minimum necessary opening.

When a power failure occurs during the descent operation, the solenoid coil 9a is de-energized, the electromagnetic pilot valve 9 is closed, and the operating oil in the oil chamber 7b is supplied to the oil chamber 7d through the throttle 11. Therefore, the valve element 7a moves in the closing direction, and the main control valve 7 closes. At this time, since the hydraulic oil supplied to the oil chamber 7d passes through the throttle 11, the main control valve 7 closes slowly. Therefore, a large shock is not applied to the car 2. Thus, the car 2 does not run free even during the descent operation.

[0013]

In the above prior art, when the descent operation is completed, the electromagnetic pilot valve 9 is closed after the main control valve 7 is closed. If the electromagnetic pilot valve 9 does not close due to foreign matter in the oil, the rear oil chamber 7d
Is released from the hydraulic pump 5 to the tank 6, the closed main control valve 7 starts to open again, and the car 2 descends. In addition, when the power failure occurs, the main control valve 7 is closed by closing the electromagnetic pilot valve 9. Similarly, if the electromagnetic pilot valve 9 is not closed, the main control valve 7 cannot be closed and the car 2 descends.

Further, if the electromagnetic pilot valve 9 is erroneously excited when the pressure on the pump side oil chamber 7c of the main control valve 7 has not risen due to a failure of the electric motor 4 or the hydraulic pump 5, etc. The control valve 7 opens, and the car 2 descends.

[0015]

According to the present invention, a means for opening and closing by the pressure of the oil chamber on the pump side is provided in series with the second control valve. The opening of the control valve can be prevented.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention is provided with a valve for preventing the flow of hydraulic oil from the rear side oil chamber to the pump side oil chamber when the pressure on the pump side oil chamber side is equal to or lower than a predetermined value. When the pressure on the pump-side oil chamber side becomes equal to or less than a predetermined value, this valve is closed to prevent the main control valve from being opened. In another embodiment of the present invention, a pressure control valve or a pilot operation check valve is used as the valve.

[0017]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a diagram corresponding to FIG. In the figure, 20 is the first
A pressure control valve installed between an electromagnetic pilot valve 8 as a control valve and an electromagnetic pilot valve 9 as a second control valve;
Reference numeral 1 denotes the pilot circuit, and the same reference numerals as those in FIG.

The operation of the present embodiment will be described. Since the electromagnetic pilot valve 9 is not operated during the ascending operation, the pressure control valve 20 is irrelevant, and the operation is the same as that of FIG. During the lowering operation of the car 2, the hydraulic pump 5 is driven to control the flow rate of the working oil, so that the pilot circuit 2
1 is higher than the set value of the pressure control valve 20, and the pressure control valve 20 is open. When the car 2 arrives on the destination floor, the flow rate of the hydraulic oil in the main control valve 7 becomes zero, the main control valve 7 closes, the electric motor 4 stops, and the solenoid coils 8a, 9a are de-energized. To be. When the electric motor 4 stops and the hydraulic pump 5 stops, the pressure of the main control valve 7 on the pump-side oil chamber 7c side drops sharply.

Here, if the electromagnetic pilot valve 9 cannot be closed for some reason, the hydraulic oil in the rear side oil chamber 7d will flow to the pump side oil chamber 7c through the pressure control valve 20 and the electromagnetic pilot valve 9. However, since this circuit has the resistance of the check valve 10 and the like, a response delay occurs when the main control valve 7 opens. On the other hand, the pressure control valve 20 closes with almost no response delay due to the pressure drop in the pump-side oil chamber 7c, so that the hydraulic oil in the rear-side oil chamber 7d does not flow out, and the main control valve 7 closes.

Even if the electromagnetic pilot valve 9 is erroneously excited when the pressure in the pump-side oil chamber 7c has not risen due to a failure of the electric motor 4 or the hydraulic pump 5, the pressure control is performed in the same manner as described above. Since the valve 20 is closed, the main control valve 7 does not open.

As described above, according to the present embodiment, since the pressure control valve 20 which opens and closes by the pressure of the pump-side oil chamber 7c is disposed between the electromagnetic pilot valves 8 and 9, Even if an abnormality such as a failure occurs, the opening of the main control valve 7 can be prevented, and the lowering of the car 2 can be prevented.

In the above embodiment, the pressure control valve 20 is used. However, the present invention is not limited to this, and any device capable of performing the same operation, such as a pilot operation check valve, may be used.

[0023]

As described above, according to the present invention,
Only by adding a simple device, it is possible to prevent the car from lowering due to a failure of the electromagnetic pilot valve or the like, and to improve the safety of the hydraulic elevator.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an overall configuration of a hydraulic elevator according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing the entire configuration of a conventional hydraulic elevator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic jack 2 Car 3 Control part 7 Main control valve 7a Valve body 7b Jack side oil chamber 7c Pump side oil chamber 7d Back side oil chamber 7e Spring 8 First control valve 9 Second control valve 20 Pressure control valve 21 Pilot circuit

Claims (2)

[Claims] A hydraulic jack for raising and lowering a car; a hydraulic pump for supplying and discharging hydraulic oil to and from the hydraulic jack; and a hydraulic pump disposed between the hydraulic jack and the hydraulic pump;
A main control valve that allows hydraulic oil to flow in both forward and reverse directions, wherein the main control valve includes a valve body that opens and closes a passage for hydraulic oil, a jack-side oil chamber connected to a hydraulic jack, A pump-side oil chamber connected to a pump side, a rear-side oil chamber that urges the valve body in the closing direction at high pressure, and a unit that constantly urges the valve body in the closing direction, First means for allowing hydraulic oil to flow between the jack-side oil chamber and the rear-side oil chamber during the ascending operation of the car, and the back-side side from the jack-side oil chamber during the descending operation of the car Second means for restricting the flow rate of the hydraulic oil to the oil chamber, and third means for allowing the flow of the hydraulic oil from the rear oil chamber to the pump oil chamber during the lowering operation of the car. When the pressure on the pump-side oil chamber side is equal to or less than a predetermined value, the rear-side oil chamber Hydraulic elevator apparatus characterized by comprising means for preventing the flow of hydraulic fluid to et the pump-side oil chamber. 2. The hydraulic elevator apparatus according to claim 1, wherein the means for blocking the flow of the hydraulic oil is a pressure control valve or a pilot operation check valve.