JPH05286671A - Control device of hydraulic elevator - Google Patents

Abstract

PURPOSE:To enhance the operating reliability of a hydraulically operated eleva tor control device, in which the operating speed of a hydraulic jack is controlled through changing of the rate of pressure oil flow made by a hydraulic pump. by furnishing an aux. pump on the way of a piping leading from the hydraulic pump to a check valve, and therewith supplying pressure oil before the check valve is put in the opening motion. CONSTITUTION:In a control device for a hydraulically operated elevator including a hydraulic pump 8 to be driven by a motor, the revolving speed of the pump 8, i.e., its discharge amount, is controlled through frequency control of the revolving speed of motor 13 by a speed control device 15 and an inverter 18, and the discharge oil of the pump 8 is supplied to a cylinder 3 of a hydraulic jack 2 by opening a solenoid-operated selector valve 12, and thereby an elevator cage 1 is elevated with the aid of a pluger 4. Therein an aux. pump 22 to feed pressure oil from a tank 10 is furnished in a pressure oil feeding/receiving pipe 9a leading between the hydraulic pump 8 and the selector valve 12. The internal pressure of the pipe 9a is raised by feeding the pressure oil before the valve 12 is opened and the pressure oil flows to the hydraulic pump 8 side from the hydraulic jack 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic elevator control device.

[0002]

2. Description of the Related Art FIG. 2 is a block diagram of a conventional hydraulic elevator control device.

In the figure, 1 is a car for an elevator, 2 is a hydraulic jack consisting of a cylinder 3 and a plunger 4 inserted in the cylinder 3, 5 is a sheave attached to the upper part of the plunger 4, and 6 is a sheave 5. The rope 6 is attached to the car 1 at one end and to the foundation 7 at the other end.

8 is connected to an oil tank 10 and
It is a reversibly rotatable hydraulic pump that is connected to the cylinder 3 of the hydraulic jack 2 by a pressure oil delivery pipe 9 and fills the cylinder 3 with pressure oil. An electromagnetic switching valve 12 that functions as a check valve at all times and is switched by being energized by the electromagnetic coil 11 to conduct electricity in the reverse direction is provided in the middle of the pressure oil delivery pipe 9.

Reference numeral 13 denotes a three-phase induction motor for a hydraulic pump which is directly connected to and drives the hydraulic pump 8. Reference numeral 14 is attached to the three-phase induction motor 13 and detects the number of revolutions of the hydraulic pump 8 to detect the detected value. 15 is a speed detector which is transmitted to 15.

In the figure, R, S, and T are three-phase AC power supplies, 16 is a rectifier circuit that converts three-phase AC from these power supplies into DC, and 17 is a capacitor that smoothes this DC.
Reference numeral 18 is an inverter for controlling a DC voltage into a three-phase alternating current having a variable voltage and a variable frequency, and 19 is a three-phase alternating current power source R, S, T when the direct current obtained through the inverter 18 is regenerated. It is a regeneration inverter that is returned to.

Further, 20a and 20b are deceleration command switches for decelerating the moving car 1 and 21
Reference numerals a and 21b are stop command switches for stopping the car 1. The signals emitted from these switches are input to the speed control device 15 in the same manner as the signal from the speed detector 14, and the speed control is performed. The device 15 receives these signals and outputs the control signal 15a to control the inverter 18.

Next, the operation during operation will be described.

During the ascending operation, the electric motor 13 rotates according to the operation command. At this time, the frequency is controlled by the speed control device 15 and the inverter 18, and the electric motor 13
The rotation speed of is controlled. As a result, the number of revolutions of the hydraulic pump 8, and therefore the discharge amount of the hydraulic pump 8, is controlled, and the discharged pressure oil opens the electromagnetic switching valve 12 and the hydraulic jack 2
Flows into the cylinder 3, the plunger 4 is pushed up, and the car 1 rises according to a predetermined speed pattern.

On the other hand, during the descending operation, the electromagnetic coil 11 of the electromagnetic switching valve 12 is excited by the operation command, and the circuit of the electromagnetic switching valve 12 is opened. Therefore, the pressure oil is pushed out from the cylinder 3 of the hydraulic jack 2 by the own weight of the car 1. The pushed pressure oil rotates the hydraulic pump 8 to utilize the dynamic braking of the electric motor 13 to control the descending speed of the car and regenerate power. Also at this time, the electric motor 13 is controlled to the required rotation speed by the speed control device 15 and the inverter 18.

By the way, according to the above-mentioned conventional structure, since the pressure oil filled in the cylinder 3 is applied with the pressure corresponding to the weight of the car 1 while the car 1 is stopped, the hydraulic pressure in the cylinder 3 There is a pressure difference between the oil pressure in the pressure oil delivery pipe 9a extending from the hydraulic pump 8 to the electromagnetic switching valve 12. Therefore, the electromagnetic switching valve 1 is activated by the descending operation command.
When the electromagnetic coil 11 of No. 2 is excited and the electromagnetic switching valve 12 is opened, the car 1 is once abruptly lowered until the hydraulic pressure in the cylinder 3 and the hydraulic pressure in the pressure oil transfer pipe 9a are balanced. A phenomenon occurs.

When oil leakage occurs inside the hydraulic pump 8 while the car 1 is stopped, or oil contracts due to a decrease in oil temperature, the electromagnetic switching valve 12 and the electromagnetic switching valve 12 are connected to each other. Since a space is created in the pressure oil delivery pipe 9a that connects to the hydraulic pump 8, the car 1 is further rapidly lowered when the descent operation is started.

Therefore, conventionally, when the operation is started, the hydraulic pump 8 is once rotated in the raising direction of the car 1 to raise the internal pressure of the pressure oil delivery pipe 9a connecting the electromagnetic switching valve 12 and the hydraulic pump 8. Alternatively, the amount of oil corresponding to the oil leak or the pressure drop is compensated in the pressure oil delivery pipe 9a, and then the electromagnetic switching valve 12 is controlled to open to avoid the sudden lowering phenomenon of the car 1. I was about to.

[0014]

However, in the above-mentioned conventional method, the hydraulic pump 8 is once rotated in the raising direction of the car 1 to make up for the amount of oil, and then the hydraulic pump 8 is stopped, and then the car 1 is lowered. Since it is rotated to, the reaction speed to the descending command is slow, and the control must be complicated.

Further, if the timing of stopping the hydraulic pump 8 is delayed, the car 1 rises to make passengers feel uneasy, while if the timing of stopping the hydraulic pump 8 is early, the car 1 descends. Therefore, there is an inconvenience such as the occurrence of vibration at the start of descending.

[0016]

In order to solve the above-mentioned problems, an invention according to claim 1 is to provide a hydraulic jack for moving a car up and down, a hydraulic pump for distributing pressure oil to the hydraulic jack, and a hydraulic pump. An oil tank for sending and receiving pressure oil to and from the hydraulic pump, a check valve provided in the middle of piping from the hydraulic pump to the hydraulic jack, and an induction motor connected to the hydraulic pump to drive the hydraulic pump. A control device for a hydraulic elevator that controls an operating speed of the hydraulic jack by controlling a frequency of a power source of an electric motor to change a rotation speed thereof and a flow rate of pressure oil by the hydraulic pump, wherein the hydraulic pump controls the operating speed of the hydraulic jack. An auxiliary pump that feeds pressure oil from the hydraulic tank is connected to the check valve in the middle of the piping before the check valve is opened.

According to a second aspect of the present invention, in addition to the above configuration, the auxiliary pump further comprises a pump having a smaller discharge amount than the hydraulic pump.

[0018]

The operation common to the inventions according to claims 1 and 2 is as follows.

The auxiliary pump operates before opening the check valve to feed pressure oil into the pipe connecting the hydraulic pump and the check valve. As a result, the pressure oil is supplied into the pipe connecting the hydraulic pump and the check valve, and the pipe internal pressure rises. After that, the auxiliary pump is stopped, the check valve is opened, the pressure oil moves from the hydraulic jack side toward the hydraulic tank, and the car starts to descend.

Therefore, even if the check valve is opened to lower the car, the car does not suddenly descend.

Since the hydraulic pump is not reversed as in the conventional case, the reaction speed with respect to the descending command is fast.

Further, in the invention according to claim 2, since the discharge amount of the auxiliary pump is smaller than that of the hydraulic pump, the hydraulic jack does not immediately operate even if the timing of stopping the auxiliary pump is slightly delayed. There is no danger of the car rising.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of a control device for a hydraulic elevator according to an embodiment of the present invention.

In this figure, the same or corresponding parts as those of the conventional structure shown in FIG. 2 are designated by the same reference numerals as those used above, and the duplicated description will be omitted.

In FIG. 1, reference numeral 22 is a pressure oil delivery pipe 9a connecting the hydraulic pump 8 and the electromagnetic switching valve 12.
It is a pump for sending pressure oil from the hydraulic tank 10 into the inside. The pump 22 is an auxiliary pump having a smaller discharge amount than the hydraulic pump 8 as a main pump that feeds pressure oil to the hydraulic jack 2 to move the car 1 up and down.

On the downstream side of the auxiliary pump 8 in the hydraulic pressure transmission,
An auxiliary pump check valve 23 is provided to prevent the pressure oil sent under pressure from returning in the direction of the auxiliary pump 8.

Further, the auxiliary pump 22 is connected to an auxiliary pump three-phase induction motor 24 for driving the auxiliary pump 22, and the auxiliary pump three-phase induction motor 24 is connected to the speed control device through a normally open contact. It is connected to 15.

The operation of the control device of this embodiment having the above construction will be described. When the elevator user instructs the descent operation to the intended lower floor, first, the auxiliary pump three-phase induction motor 24 is activated to operate the auxiliary pump 22.
To drive. As a result, the pressure oil in the hydraulic tank 10 is pressure-fed into the pressure oil delivery pipe 9a connecting the main pump 8 and the electromagnetic switching valve 12, and the oil pressure in the pressure oil delivery pipe 9a rises.

After the hydraulic pressure in the pressure oil delivery pipe 9a has sufficiently risen, the operation of the auxiliary pump 22 is stopped, the electromagnetic coil 11 of the electromagnetic switching valve 12 is excited, and the circuit of the electromagnetic switching valve 12 is opened. The pressure oil flows from the hydraulic jack 2 side to the main pump 8 side. Subsequent operations are the same as in the conventional case.

As described above, according to the control device of this embodiment, the discharge amount separately provided before the electromagnetic switching valve 12 opens and the pressure oil flows from the hydraulic jack 2 side to the main pump 8 side. By the auxiliary pump 22 having a small size, the pressure oil is fed into the pressure oil delivery pipe 9a connecting the main pump 8 and the electromagnetic switching valve 12, and the internal pressure of the pressure oil delivery pipe 9a is increased. Therefore, before the car 1 starts the descending operation, the hydraulic pressure in the pressure oil transfer pipe 9a becomes equal to or close to the hydraulic pressure in the cylinder 3 of the hydraulic jack 2, so that the car 1 is lowered. Therefore, even if the electromagnetic switching valve 12 is opened, the car 1 does not drastically descend, and the vibration of the car 1 is also prevented.

Since the auxiliary pump 22 has a discharge amount smaller than that of the main pump 8, the electromagnetic switching valve 12 is opened immediately by the operation of the auxiliary pump 22 to operate the hydraulic jack 2. Absent.

Further, according to the present invention having the above structure, there is an advantage that the position of the car 1 can be corrected safely and surely when the car 1 is stopped for a long time.

That is, when the car 1 is stopped for a long time, the car 1 may sink from the stop position due to oil leakage in the electromagnetic switching valve 12 and the packing portion of the main pump 8. In such a case, if the auxiliary pump 22 is driven, the auxiliary pump 22 has a discharge amount smaller than that of the main pump 8. Therefore, the car 1 rises very little by little, and the car 1 position correction can be done safely and surely.

Further, oil is circulated between the electromagnetic switching valve 12 and the main pump 8 to drive the main pump 8 and the auxiliary pump 22 so that the oil temperature becomes equal to or higher than a predetermined value. If mutual control of
Since the oil temperature is prevented from lowering, it is possible to eliminate problems such as a delay in the response speed of the electromagnetic switching valve 12 and an increase in leakage of the main pump 8.

[0036]

According to the inventions of claims 1 and 2, since the start shock at the time of the descent start can be alleviated, there is an advantage that an elevator having a good riding comfort and high safety can be provided.

In the invention according to claim 2, the hydraulic jack does not operate immediately even if the auxiliary pump operates, so that there is an effect that it is safe in use.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing a conventional technique.

[Explanation of symbols]

 1 Cage 2 Hydraulic jack 8 Hydraulic pump (main pump) 10 Oil tank 12 Check valve (electromagnetic switching valve) 13 Induction motor 22 Auxiliary pump

Claims (2)

[Claims] 1. A hydraulic jack for moving a car up and down, a hydraulic pump for circulating pressure oil to the hydraulic jack, an oil tank for sending and receiving pressure oil to and from the hydraulic pump, and a hydraulic pump to the hydraulic jack. The hydraulic pump includes a check valve provided in the middle of the pipe and an induction motor that is connected to the hydraulic pump and drives the hydraulic pump. The frequency of the power source of the induction motor is controlled to change the rotation speed of the hydraulic pump. In the control device of the hydraulic elevator for controlling the operating speed of the hydraulic jack by changing the flow rate of the pressure oil by the, in the middle of piping from the hydraulic pump to the check valve, before the opening operation of the check valve, A control device for a hydraulic elevator, characterized in that an auxiliary pump for sending pressure oil from a hydraulic tank is connected. 2. The hydraulic elevator control device according to claim 1, wherein the auxiliary pump is a pump having a smaller discharge amount than the hydraulic pump.