JPH09315733A - Hydraulic elevator device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a device which can prevent a car from being accelerated at the time of power failure with a relatively simple means. SOLUTION: While a car 2 is going up, a solenoid coil 8b is energized, and while the car is going down, solenoid coils 8a, 9a are energized, by which a poppet 7a is constituted so as to move according to the flow rate of hydraulic oil running through a main control valve 7. The opening of the main control valve 7 reaches a minimum corresponding to the speed of the car 2. At the time of power failure, the main control valve 7 can close immediately, thus it is possible to prevent the car 2 from being accelerated.

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, when a power failure occurs during low-speed operation, the electric motor and hydraulic pump stop, while the main control valve is fully open, so the flow rate of hydraulic oil increases rapidly, causing the car to enter the free-run state, and then the main control valve. As the control valve closes, the car slows down, and when the main control valve closes the car stops.

As a conventional technique for preventing this free run, there is JP-A-5-201656. This prior art uses an electromagnetic pilot valve to variably control the opening of the main control valve.By changing the pulse train signal output to the solenoid coil of the electromagnetic pilot valve, the speed of the car can be controlled. Accordingly, the opening of the main control valve is adjusted to the minimum required opening. As a result, even when a power failure occurs during the low speed descent operation of the car, the main control valve can be quickly closed and the car can be quickly stopped without increasing the speed.

[0004]

In the case of the above-mentioned prior art,
To control the electromagnetic pilot valve, a pulse signal corresponding to the speed of the car is required. Therefore, the car speed,
In order to make the opening of the main control valve correspond to the car speed, it is necessary to output the pulse signal based on the signal of the plunger speed or the flow rate flowing through the cylinder and its signal, or based on the operation command. A complex controller was needed. The present invention is intended to solve this conventional problem, and provides a control device for a hydraulic elevator capable of performing a reliable operation with a simpler configuration.

[0005]

DISCLOSURE OF THE INVENTION The present invention comprises means for maintaining an open or closed state of a car during a lifting operation, and the hydraulic pressure in each oil chamber constituting the main control valve and the hydraulic oil flowing in the main control valve. Since the opening degree of the main control valve is automatically changed depending on the flow rate and the direction, the complicated control device as in the prior art is unnecessary.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention include a valve body, an oil chamber on the jack side, an oil chamber on the pump side, an oil chamber on the rear side of the valve body, and
A main control valve having a means for urging the valve element in the closing direction is provided, and it enables the flow of hydraulic oil between the jack side oil chamber and the back side oil chamber during the ascending operation of the car. First means, and second means for limiting the flow rate from the jack side oil chamber to the back side oil chamber during the descending operation of the car,
And a third means for allowing the hydraulic oil to flow from the back side oil chamber to the pump side oil chamber during the descent operation of the car, and the first and second means are provided even during a power failure. By maintaining the function, the opening degree of the main control valve can be minimized to prevent free run at the time of power failure without performing complicated control.

According to another embodiment of the present invention, a valve body (for example, poppet) of the main control valve is provided with a spring for urging the poppet in a closing direction, and a jack side oil chamber and a rear side oil of the main control valve are provided. A first electromagnetic pilot valve is arranged between the oil chamber and the chamber, and a second electromagnetic pilot valve is arranged between the pump-side oil chamber and the rear-side oil chamber. Then, the first electromagnetic pilot valve is controlled to be opened during the ascending operation of the car and maintained in the closed state during the descending operation of the car, and the second electromagnetic pilot valve is controlled to be opened only during the descending operation of the car. By doing so, the opening of the main control valve is set to the minimum required opening according to the speed of the car, and free run at the time of power failure is prevented. Furthermore,
Another embodiment of the present invention has a configuration in which a throttle is provided in parallel with the first electromagnetic pilot valve.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIG. FIG. 1 is a schematic diagram showing the overall configuration of a hydraulic elevator according to this embodiment. In the figure, 1 is a hydraulic jack for raising and lowering a car 2, 3 is a control unit for driving a hydraulic pump 5 by controlling an electric motor 4, and 6 is a tank. A main control valve 7 is a poppet 7a, a jack side oil chamber 7b connected to the hydraulic jack 1 by hydraulic piping, a pump side oil chamber 7c connected to the hydraulic pump 5, and a rear side of the poppet 7a. It has an oil chamber 7d and a compression spring 7e.

Reference numeral 8 denotes a jack side oil chamber 7b and a rear side oil chamber 7d.
The first solenoid pilot valve disposed between the 8a, 8a
b is a solenoid coil, 9 is a second electromagnetic pilot valve connected to the pump side oil chamber 7c through the check valve 10 and the other side to the back side oil chamber 7d, 9a is a solenoid coil, and 11 is a first This is a throttle arranged in parallel with the electromagnetic pilot valve 8. In addition, the solenoid coils 8a to 9 described above
b operates by the operation start and stop signals of the car 2 supplied from the control unit 3.

Next, the operation of this embodiment 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, and the pressure in the oil chamber 7c rises. Further, the solenoid coil 8b is excited to open the first electromagnetic pilot valve 8 to equalize the pressures in the oil chambers 7b and 7d. Therefore, when the valve opening force due to the pressure in the oil chamber 7c and the oil chamber 7b exceeds the pressure in the oil chamber 7d and the valve closing force due to the spring 7e, the poppet 7a starts to open and the car 2 starts to rise.

The valve opening at this time will be described in detail. Valve opening force = P _O (S ₁ −S ₂ ) + P _I · S ₂ valve closing force = P _O · S ₁ + K (K = pushing force of spring 7e, S ₁ = cross-sectional area of poppet 7a,
S ₂ = section area of seat portion of poppet 7a, P _I = pressure on hydraulic pump 5 side, P _O = pressure on jack 1 side) When valve opening force> valve closing force, poppet 7a begins to open, so P _O (S ₁ -S ₂ ) + P _I · S ₂ > P _O · S ₁ + K ∴P _I > P _O + K / S ₂ Therefore, when the pressure P _I on the hydraulic pump 5 side satisfies the above formula, the poppet 7 a The car 2 starts to open and the car 2 starts to rise.

Then, the flow rate of the hydraulic oil flowing through the main control valve 7 increases as the rotation speed of the electric motor 4 increases, and the opening degree of the main control valve 7 (movement of the poppet 7a moves as the flow rate increases). Amount) becomes larger and the car 2 accelerates. Car basket 2
When the vehicle runs at the rated speed and reaches the deceleration start point, the rotational speed of the electric motor 4 decreases, so the flow rate of the hydraulic oil in the main control valve 7 decreases, and the opening degree of the main control valve 7 decreases. To go. 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. Further, the first electromagnetic pilot valve 8 holds the same 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, as a power failure occurs during the ascending operation and the flow rate of the working oil in the main control valve 7 becomes 0, the main control valve 7 closes quickly, so that the working oil flows backward and the car 2 becomes free. It does not cause an orchid.

Next, the case of the descending 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 poppet 7a starts to open and the car 2 starts to descend.

Explaining the valve opening at this time in detail, the valve opening force = P _O (S ₁ −S ₂ ) + P _I · S ₂ valve closing force = P _I · S ₁ + K, similarly to when the valve is rising. In the force equation, the pressure in the oil chamber 7d is slightly larger than the pressure P _I on the hydraulic pump 5 side, but here it is P _I for simplicity. When the valve opening force> the valve closing force, the poppet 7a starts to open, so P _O (S ₁ −S ₂ ) + P _I · S ₂ > P _I · S ₁ + K ∴P _I <P _O −K / (S ₁ − S ₂ ) Therefore, when the pressure P _I on the hydraulic pump 5 side satisfies the above expression, the poppet 7a starts to open and the car 2 starts to descend.

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, the rotation speed of the electric motor 4 decreases, so that the flow rate of the hydraulic oil in the main control valve 7 decreases and the main control valve 7 The opening of will become smaller. 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 descending operation, the solenoid coil 9a is de-energized, the electromagnetic pilot valve 9 is closed, and the hydraulic oil in the oil chamber 7b is supplied to the oil chamber 7d through the throttle 11. Therefore, the poppet 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. In this way, even during descent operation,
Cage 2 does not cause a free run.

As described above, according to this embodiment, the first electromagnetic pilot valve 8 maintains the open state and the second electromagnetic pilot valve 9 maintains the closed state during the ascending operation, and the descending operation. The first solenoid pilot valve 8 is closed while the second
Since the electromagnetic pilot valve 9 of FIG. 6 only maintains the open state, it is not necessary to output the pulse signal according to the speed of the car to control the electromagnetic pilot valve, unlike the prior art.
Therefore, the opening degree of the main control valve 7 can be automatically adjusted with a simpler structure than that of the conventional technique.

[0020]

As described above, according to the present invention,
The opening of the main control valve can be set to the minimum required opening according to the speed of the car without requiring a complicated control device, and the free running of the car at the time of power failure can be prevented. it can.

[Brief description of drawings]

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

[Explanation of symbols]

 1 Hydraulic Jack 2 Cage 3 Control Unit 4 Electric Motor 5 Hydraulic Pump 7 Main Control Valve 7a Poppet 7b, 7c, 7d Oil Chamber 7e Spring 8 First Electromagnetic Pilot Valve 9 Second Electromagnetic Pilot Valve 11 Throttle

Claims (4)

[Claims] 1. A hydraulic jack for raising and lowering a car, a hydraulic pump for supplying and discharging hydraulic oil to and from the hydraulic jack via a main control valve, an electric motor for driving the hydraulic pump, and a control for controlling the electric motor. In the hydraulic elevator equipped with a section, the opening of the main control valve is automatically adjusted according to the flow rate of the working oil flowing in the main control valve by means of maintaining the open or closed state during the elevator car lifting operation. A hydraulic elevator device characterized by being configured to change. 2. The main control valve comprises a valve body, an oil chamber on the jack side, an oil chamber on the pump side, an oil chamber on the back side of the valve body, and means for urging the valve body in the closing direction. Yes, the means for maintaining the open or closed state during the elevator car ascending / descending operation allows the working oil to flow between the jack side oil chamber and the back side oil chamber during the ascending operation of the car. Means and
Second means for limiting the flow rate from the jack side oil chamber to the back side oil chamber during the descent operation of the car, and from the back side oil chamber to the pump side oil chamber during the descent operation of the car. The hydraulic elevator according to claim 1, further comprising: a third means for allowing the flow of hydraulic oil, wherein the first and second means are configured to maintain their functions even during a power failure. apparatus. 3. The main control valve comprises a poppet, an oil chamber on the jack side, an oil chamber on the pump side, an oil chamber on the back side of the poppet, and a spring for urging the poppet in a closing direction. The means for maintaining the open or closed state of the car during the up-and-down operation is the first one arranged between the jack side oil chamber and the rear side oil chamber.
And a second electromagnetic pilot valve disposed between the pump-side oil chamber and the rear-side oil chamber, wherein the first electromagnetic pilot valve is opened during the ascending operation of the car, 2. The hydraulic elevator apparatus according to claim 1, wherein the second electromagnetic pilot valve is controlled to remain closed during the descent operation and to be opened only during the descent operation of the car. 4. The hydraulic elevator system according to claim 3, wherein a throttle is arranged in parallel with the first electromagnetic pilot valve.