JPH0398964A - Speed controller of hydraulic elevator - Google Patents

Abstract

PURPOSE:To improve riding comfortableness of cage, and to contract car starting time by inputting an output signal of a pressure detector provided between a hydraulic pump and an electromagnetic change over valve to a descent running pattern generation circuit. CONSTITUTION:On the side of a hydraulic pump 8 of an electromagnetic change over valve 9 in a hydraulic piping extended to a hydraulic jack 3 from the hydraulic pump 8 through the electromagnetic change-over valve 9, a pressure detector Sp is mounted, and an output signal Rpa of a pattern generation com mand relay that is actuated by an output signal Spa, is input to a descent running pattern generation circuit 22. When the starting condition is provided, a bias pattern is generated by a bias pattern generation circuit 20, whereby oil is gradually flown in between the hydraulic pump 8 and the electromagnetic change-over valve 9 through pressure driving, and a gap is filled therewith and pressure is raised. When the oil pressure reaches a set pressure of the pressure detector Sp, the descent running pattern generation circuit 22 is actuat ed by an output contact, and the outputs of the descent running pattern and that of the bias pattern are added up by an adder 23, whereby an induction motor 7 is decelerated.

Description

[Detailed description of the invention] [Purpose of the invention] (Industrial application field) The present invention relates to a speed control device for a hydraulic elevator.

(Prior Art) Generally, a flow control method is adopted for car speed control of a hydraulic elevator, in which a flow control valve is used to control hydraulic fluid in a hydraulic circuit.

Conventional flow control uses a flow control valve to adjust the oil from a constant-discharge hydraulic pump driven by a constant-rotation electric motor when the car is ascending, and when the car is descending, the oil is recirculated from the cylinder to the tank by the car's own weight. It was adjusted with a flow control valve. However, this system circulated excess oil, resulting in large energy losses and a significant rise in oil temperature.

In contrast, recently, so-called motor rotation speed control has been developed, which controls the rotation speed of the AC induction motor used to drive the hydraulic pump by changing the voltage and frequency over a wide range by changing the voltage and frequency using semiconductor converters using diodes, thyristors, etc. method has been adopted.

In this method, the discharge amount of a constant discharge hydraulic pump is controlled by changing the rotational speed of an AC induction motor, which is a driving motor.

Speed control of a hydraulic elevator using this method will be explained based on FIGS. 4 to 8.

A hydraulic jack 3 with a built-in plunger 2 is installed behind the hydraulic elevator car 1, and a lobe 5 with one end fixed to the foundation 4 wraps around a sheave 6 attached to the top of the plunger 2 and suspends the car 1 with the other end. It is configured to be lowered.

The hydraulic circuit of this hydraulic elevator has a configuration in which the discharge side of a reversibly rotatable hydraulic pump 8 directly connected to an AC induction motor 7 is connected to the hydraulic jack 3 via an electromagnetic switching valve 9, and the suction side is connected to an oil tank io. It becomes.

The main circuit of the AC induction motor 7 is a three-phase AC power supply R. S. T
．． It is converted to direct current through a rectifier circuit 11, and then connected to a capacitor l.
2, the inverter 13 converts the direct current, outputs a three-phase alternating current of variable voltage and variable frequency through pulse width control, and supplies this to the alternating current induction motor 7. Also, during regeneration of the induction motor 7, the regeneration inverter l4 converts the three-phase AC power supply 1? ．． S. T. The regenerated power is returned to the

Start command circuit (Figure 6), descending travel pattern command circuit (
Speed control device i consisting of circuits such as Fig. 7)
Signals from the speed generator i6, the deceleration switch 17.17, the stop switch 18.18, etc. are also input to the inverter 5, and a control signal is output to the inverter 13.

A hydraulic elevator having such a configuration is operated as follows.

In the ascending operation of the hydraulic elevator, when the induction motor 7 rotates with the first operation command, the speed control device 15 and the inverter l
3 controls the frequency and controls the rotational speed of the induction motor 7, that is, the amount of oil discharged from the hydraulic pump 8, and the discharged pressure flows into the hydraulic jack 3 through the electromagnetic switching valve 9, and the car l is operated in an upward direction according to a predetermined speed pattern A shown in FIG. 5 as follows.

Car 1 starts and accelerates according to the start command, rises at the rated speed until it reaches the deceleration position, and then deceleration switch 1 on the rising side is activated.
7 is activated, the car 1 starts to decelerate to a certain landing speed, and when it reaches the upper limit position at this speed, the stop switch 18 on the rising side is activated to stop the car.

On the other hand, in descending operation, the electromagnetic switching valve 9 opens in response to a driving command, the pressure oil from the hydraulic jack 3 is discharged by the weight of the car 1, the hydraulic pump 8 rotates, and the electric motor 7 uses dynamic braking to control the car 1. It controls the descent speed of the aircraft and regenerates power.

By the way, in such a downward traveling hydraulic circuit, when the car 1 is stopped, a space is created between the switching valve 9 and the hydraulic pump 8 due to oil leakage and contraction of oil due to a drop in oil temperature, resulting in a drop in pressure. In this state, the switching valve 9 opens in response to a descending operation command. (If the suction amount of the hydraulic pump is larger than the flow rate corresponding to the opening degree of the electromagnetic switching valve, cavitation will occur, so the opening degree of the valve should be made quite large. When the pressure oil rapidly flows into the above space and fills this space, the pressure oil flows into the hydraulic pump, and the flow out from the hydraulic jack is rapidly reduced. Because the pressure oil flows in this manner, the car 1 suddenly descends, then immediately stops and vibrates. The car then vibrates and increases its speed as the rotation of the hydraulic pump increases until it reaches a constant speed.

In this way, when descending operation starts, the ride is uncomfortable and the passengers feel uneasy, so in order to avoid this, at the start of descending operation, the hydraulic pump 8 is rotated at a very low speed in the upward direction to reduce the above-mentioned water leakage pressure. The amount of surface roughness corresponding to the decrease is compensated for, and then the switching valve 9 is opened to control the vibration so as not to occur.

This descending operation control will be explained in more detail using FIGS. 6 to 8.

When the activation conditions such as the call signal and door closed detection signal are met,
The start command circuit (Fig. 6) operates, the start relay Rs operates, and the descending travel pattern generation command circuit (Fig. 7) operates, which issues a command to cause the hydraulic pump 8 to perform slow rotation and preload operation. from the bias pattern generation circuit 20 for
The bias pattern b in the figure is generated. The preload operation of the bias pattern generation circuit 20 reaches the one-step value at the rising point time t2, and on the other hand, when the delay point t3 is reached after a predetermined time by the delay circuit 2l in the descending traveling pattern generation command circuit, the descending traveling pattern generating circuit 22 is activated. The adder 23 adds the descending running pattern and the bias pattern to output the pattern signal C in FIG. 8, and the induction motor 7 follows this pattern. Therefore, drive down.

(Problem to be Solved by the Invention) By the way, the amount of oil leakage that occurs when the car of a hydraulic elevator is stopped and the amount of oil contraction due to a decrease in the temperature of the hydraulic elevator vary considerably depending on the time when the car is stopped and the temperature conditions. occurs, so the speed control device outputs a bias pattern,
The execution of the preload operation is controlled, in which case: l. If the amount of oil leakage or oil contraction is greater than the amount of oil in preload operation, there will be a large vibration at the start of descent due to insufficient preload.2. If the amount of oil leakage or oil contraction is less than the amount of oil in preload operation, the car may rise once and then fall. 3. If the car is stopped for a short time and the amount of oil leakage and oil contraction is very small, the upward movement described in 2 above becomes noticeable.
Situations such as longer car start times may occur.

It is an object of the present invention to solve the above-mentioned problems, improve the ride comfort of the car, and shorten the car start time.

[Structure of the invention]

(Means for solving the problem) In order to achieve the above purpose, a conventional delay circuit (2 in Fig. 7) is used.
Instead of 1), a pressure detector is provided between the hydraulic pump and the electromagnetic switching valve, and the output signal of this detector is input to the downward travel pattern generation circuit.

(Function) When the hydraulic pressure flowing between the hydraulic pump and the electromagnetic switching valve reaches a set value, the normally open contact of the pressure detector closes, and this (output signal) activates the downward travel pattern generation circuit.

(Example) A speed control device for a hydraulic elevator according to the present invention will be described based on an example shown in FIGS. 1 to 3.

On the hydraulic pump side of the electromagnetic switching valve 9 in the hydraulic piping from the hydraulic pump 8 to the hydraulic jack 3 via the electromagnetic switching valve 9,
Install the pressure detector SP. And this pressure sensor SP
The output signal (output contact RPa) of the pattern generation command relay activated by the output signal (output contact) SPa is inputted to the downward running pattern generation circuit 22 instead of the delay circuit.

The operation of descending travel control for a car constructed in this way will be explained.

When the starting conditions are satisfied, the starting command circuit (FIG. 2) is activated, the starting relay is energized, and the descending travel pattern command circuit (FIG. 3) is activated. That is, the bias pattern b in FIG. 8 is generated by the bias pattern generation circuit 20, preload operation is started, and a constant speed is reached at t2. Due to the pre-pressure operation, oil gradually flows between the hydraulic pump 8 and the electromagnetic switching valve 9, filling the space and increasing the pressure. Oil pressure is pressure detector S
When the set pressure of P is reached, the output contact SP of the pressure detector SP
The descending running pattern generation circuit 22 is activated by a, and the adder 23 adds the outputs of the descending running pattern and the bias pattern, and outputs the batten signal C shown in FIG.

The dielectric motor 7 decelerates according to this output pattern signal,
Eventually, the car 1 rotates in the opposite direction and reaches a constant speed, and when the descending side deceleration switch {7 is turned off, deceleration begins. When the car 1 reaches the lower limit position and the stop switch 18 is turned off, the induction motor 7 and hydraulic pump 8 are turned off. When the car 1 stops, the electromagnetic switching valve 9 closes and the car 1 stops.

As described above, with this configuration, even if the amount of oil leakage between the hydraulic pump 8 and the electromagnetic switching valve 9 and the amount of contraction of the ura differ due to differences in the length of the stop time of the car 1 and the temperature conditions, ,
When the pressure between the hydraulic pump 8 and the electromagnetic switching valve 9 reaches the set value due to the preload operation, the preload operation is ended and the descending operation is started, thereby eliminating large vibrations and malfunctions at the descending start caused by different conditions. This eliminates the need for a long car start time.

〔Effect of the invention〕

According to the present invention, it is possible to obtain a hydraulic elevator which is free from shock when the car starts descending, shortens the start time, and provides a comfortable ride.

[Brief explanation of drawings]

Fig. 1 is a control system diagram of a hydraulic elevator according to the present invention, Fig. 2 is a start command circuit diagram of the speed control device in Fig. 1, and Fig. 3 is a descending travel pattern command circuit diagram of the speed control device. , FIG. 4 is a conventional hydraulic elevator control system diagram, FIG. 5 is a car running pattern diagram, FIG. 6 is a conventional starting command circuit diagram, and FIG. 7 is a conventional descending traveling pattern command circuit diagram.
FIG. 8 is an explanatory diagram of a descending travel pattern. l... Car 3... Hydraulic jack 7...
- AC induction motor 8... Hydraulic pump 9... Solenoid switching valve 15... Speed control device 20... Bias pattern generation circuit 22... Downward travel pattern generation circuit

Claims (1)

[Claims] A downward travel pattern of the car is generated in a hydraulic elevator speed control system that includes a car lower travel control circuit for the rotation speed control induction motor that drives the hydraulic pump, and a control circuit for the electromagnetic switching valve for the hydraulic circuit between the hydraulic pump and the hydraulic jack. Of the descending travel control circuit, which is composed of a circuit, a preload bias pattern generating circuit parallel to the preload bias pattern generating circuit, and an adder circuit for adding these, a hydraulic pressure installed on the hydraulic pump side of the electromagnetic switching valve is added to the descending traveling pattern generating circuit of the descending traveling control circuit. A speed control device for a hydraulic elevator, characterized in that a detector output signal is input.