JPH0517154B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a hydraulic elevator system, and particularly relates to an improvement of a control device thereof.

[Prior art]

Conventionally, hydraulic control devices for hydraulic elevators include a flow control valve system, a pump control system, and an electric motor rotation speed control system.

In the method using the flow rate control valve, the electric motor is rotated at a constant speed during elevator ascending operation, and a fixed amount of oil discharged from the hydraulic pump is returned to the tank. When a start command is given, the speed of the car is controlled by adjusting the amount of oil returned to the tank with a flow control valve.In addition, during descending operation, the descent of the car is adjusted by its own weight with a flow control valve. It controls the speed.

In this method, excess oil is circulated during ascent, and potential energy is consumed by oil heat generation during descent, resulting in large energy loss and a significant rise in oil temperature.

In order to solve the above problem, the pump discharge amount is controlled, so that only the necessary amount of oil is sent to the hydraulic jack when the elevator is running up, and the electric motor is regeneratively braked when the elevator is running down. There are two methods: motor speed control method and motor rotation speed control method.

The above pump control method uses a variable displacement pump, and the pump's discharge volume is made variable by a control device.The motor rotation speed control method controls the rotation of the induction motor by changing the voltage and frequency. Variable voltage that can control the number over a wide range,
The discharge amount of a constant discharge pump is variably controlled using a variable frequency control type electric motor (Japanese Unexamined Patent Publication No. 57-98477).

However, the method of controlling the discharge amount of the pump described above has a problem in that negative pressure is generated, which is not present in conventional flow rate control valves. In other words, in the pump discharge amount control method, when the elevator is operating downward, the solenoid switching valve is opened and the oil discharged from the hydraulic jack is controlled while the electric motor is rotating and braking. If the valve does not open, the electric motor is started by the downward start command, and the pump sucks out oil from the cylinder side. However, since the line is blocked by the solenoid switching valve, the oil to be sucked out is not allowed to flow between the solenoid switching valve and the pump. When the pressure disappears, the pressure becomes negative. When this negative pressure is generated, cavitation may occur and there is a risk that equipment such as a pump may be damaged.

Further, contrary to the above, during upward operation, even though the pump rotates and sends oil to the hydraulic jack side, the electromagnetic switching valve may not open due to clogging with dirt or the like. In this case, the pipe line between the pump and the electromagnetic switching valve becomes overpressured, causing the pipe to burst, resulting in an accident such as an oil spill. However, in the case of the flow control valve method,
Generally, a relief valve is provided, which automatically opens the pipe to the tank when the oil pressure in the pipe reaches a certain level to prevent overpressure.

Therefore, even with the pump discharge rate control system, a relief valve is required, and in order to prevent negative pressure, a check valve is provided in parallel with the pump to supply oil, as shown in Japanese Patent Publication No. 49-8176. A circuit such as this is required.

However, providing both of the above-mentioned prevention circuits separately increases the cost and creates a complicated flow valve circuit.

[Summary of the invention]

This invention solves the above problem by providing a solenoid switching valve in parallel with the pump to release abnormal pressure such as overpressure or negative pressure in the pipeline, thereby simplifying the circuit and reducing the An object of the present invention is to provide a hydraulic elevator device which is designed to reduce costs.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an example of a hydraulic elevator system of the present invention. In Figure 1, 1
1 is a hoistway, 2 is a cylinder buried in a bit of the hoistway 1, 3 is hydraulic oil filled in this cylinder 1, 4 is a plunger supported by the hydraulic oil, 5
is a car placed on the upper end of the plunger 4, 5a is a car floor, 7 is a landing floor on each floor, 8 is a cam attached to the car 5, and 9 is a moving car 5 placed in the hoistway 1. Deceleration command switch for decelerating, 1
0 is a stop command switch for stopping the car 5, which is also placed in the hoistway 1. 11 normally functions as a check valve, and is switched when the excitation coil 11a is energized so that it can also be operated in the reverse direction. This electromagnetic switching valve 11 and the cylinder 2 are connected by a pipe 6. 12 is a reversibly rotatable hydraulic pump, and one port of this hydraulic pump 12 is connected to the electromagnetic switching valve 11 via a pipe 12a.
The other port is connected to the oil tank 15 via a pipe 15a. 13 is a three-phase induction motor that drives the hydraulic pump 12; 14 is a speed generator that detects the rotation speed of the three-phase induction motor 13;
A pressure sensor 16 detects the pressure in the pipeline between the pump 12 and the electromagnetic switching valve 11. Further, a branch passage 17 communicating with the oil tank 15 is provided in the pipe 12a connecting the check valve function side of the electromagnetic switching valve 11 and the hydraulic pump 12. and excitation coil 18
An electromagnetic switching valve 18 that can conduct in both directions and opens when a is excited is provided in series.

R, S, T are three-phase AC power supplies, 21 is a rectifier circuit that converts three-phase AC into DC, and 22 is this rectifier circuit 2.
1 is a capacitor that smooths the DC current, 23 is an inverter that controls the pulse width of the DC current and converts it into variable voltage/variable frequency three-phase AC power, and 24 is a three-phase AC power source that converts the DC obtained through the inverter 23 during regeneration of the motor 13. A regenerative inverter 25 returns to R, S, and T, and 25 is a speed control device that controls the inverter 23, which includes a speed signal 1 of the speed generator 14.
4a, and the deceleration command signal 9a of the deceleration command switch 9.
and an operation command signal generated by a normally open contact 30Tc of a time-limited relay 30T (see Figure 3), which is closed from when a start command is issued until a stop command is issued;
A signal 30da generated by a normally open contact 30d of an operating contactor 30, which will be described later, is inputted, and a control signal 25a is outputted from the speed control device 25 to the inverter 23. ing. 30a to 30d are normally open contacts of the operating contactor 30 that are normally open, and are closed until a certain period of time after a start command is issued and a stop command is issued to connect the three-phase induction motor 13 to the inverter 23. be.

FIG. 2 shows details of the speed control device 25. In the figure, 40 is a delay circuit that delays a signal generated by closing a normally open contact 30Tc of a time relay 30T, which will be described later, for a predetermined time;
41U is an upward traveling pattern generating circuit which generates a traveling pattern signal which rises in response to the output signal of the delay circuit 40, decreases when the deceleration command signal 9a is input, becomes a constant low speed, and then becomes zero upon the stop command. It is something to do. Further, 41D is a descending traveling pattern generation circuit, which is controlled by the output signal of the delay circuit 40 and the reduction command signal 9a in the same manner as the ascending traveling pattern generating circuit 41U, and has a traveling pattern in the opposite direction to that of the ascending traveling pattern generating circuit 41U. It outputs a signal. 41Ua is an upward contact connected in series to the output line of the upward running pattern generating circuit 41U, which remains closed during upward operation. Further, 41Da is a downward contact which remains closed during downward operation, and is connected in series to the output line of the downward traveling pattern generating circuit 41D. Reference numeral 45 is a device for setting in advance the amount of leakage depending on the variation in the amount of leakage of the pump, the load, and the oil temperature. For example, the load and oil temperature are detected and calculated, and the hydraulic pump 1 is rotated by the amount corresponding to the amount of leakage of the hydraulic pump 12.
2 is a bias pattern generation circuit that issues a command to rotate, and when the normally open contact 30Tc is closed, the pattern signal of this bias pattern generation circuit 45 causes the hydraulic pump 12 to rotate at a rotational speed corresponding to the leakage amount at that time. When a stop command signal is generated, the normally open contact 30d is opened and the value decreases to zero after a certain period of time. 46 is an adder that adds the output signal of the running pattern generation circuit 41U or 41D and the output signal of the bias pattern generation circuit 45 to output a pattern signal;
a is output to a subtracter 48.
47 is a conversion circuit that converts the speed signal 14a of the speed generator 14 to the same voltage level as the pattern signal, and by supplying the output signal of this conversion circuit 47 to the subtracter 48, the output signal of the adder 46 is We are starting to take out the difference between the two. 49
50 is a transmission circuit that transmits the output signal of the subtracter 48 at a predetermined amplification degree, and 50 is an adder that adds the output signal of this transmission circuit 49 and the output signal of the conversion circuit 47 to output a frequency command signal ω ₀ , 51 is a function generating circuit that generates a linear voltage command signal V in response to the frequency command signal ε ₀ of the adder 50, and 52 is a function generating circuit that generates a sinusoidal three-phase AC signal based on the frequency command signal ε ₀ and the voltage command signal V. This is a reference sine wave generation circuit that outputs a signal 25a so as to be output from the inverter 23.
70a is a normally open contact connected in parallel to the normally open contact 41Ua connected to the output line of the traveling pattern generating circuit 41U, and this normally open contact 70a is a normally open contact that issues an oil temperature increase command when the oil temperature decreases. It is opened and closed by a command relay (not shown).

FIG. 3 shows a control circuit for the hydraulic elevator. In the figure, (+) and (-) are DC control power supplies, and 28 is a startup command circuit that is closed by a call signal, door closed detection signal, etc., and one end of this startup command circuit 28 is a control power supply (+ ), and the other end is connected to an abnormal pressure detection time relay 60, which will be described later.
It is connected to the control power source (-) via the timed operation contact 60c and the timed relay 30T. The start command circuit 28 also includes a normally open contact 70b of the oil temperature rise command relay, a normally closed contact 10b of the stop command switch 10, a time relay 30T, and a normally open contact 30.
Each series circuit with Ta is connected in parallel. The operating contactor 30 is connected to the control power sources (+) and (-) via the normally open contact 30Tb for timed return of the timed relay 30T and the timed operation contact 60d of the abnormal pressure detection timed relay 60. The excitation coil 11a of the electromagnetic switching valve 11 is connected between the control power supply (+) and (-) via the normally open contact 30f of the operating contactor 30, the normally open contact 30Td of the time relay 30T, and the downward contact 41Db. It is connected.

The abnormal pressure detection time relay 60 is connected to a control power source (+) via the contact 16a of the pressure sensor 16,
(-), and the contact 16a is connected to the pump 12.
It closes when the pressure between the solenoid switching valve 11 and the electromagnetic switching valve 11 is higher than the set pressure or when the pressure becomes negative. Further, a series circuit of a normally open contact 30Te of the time relay 30T and a normally open contact 60a of the abnormal pressure detection time relay 60 is connected in parallel to the contact 16a. Excitation coil 18a of the electromagnetic switching valve 18
are the normally closed contact 70c of the oil temperature rise command relay and the timed return contact 60b of the abnormal pressure detection timed relay 60.
It is connected to the control power supply (+) and (-) via.

In the hydraulic elevator system configured as described above, normally there is no abnormality in the pressure in the pipeline, the oil temperature is within an appropriate temperature range, and the oil temperature increase command relay is not energized. Therefore, the excitation coil 18a is excited by the (+)-contact 70c-contact 60b-excitation coil 18a-(-) circuit, so that the electromagnetic switching valve 18 blocks the branch passage 17.

Now, if a call occurs in the ascending direction while the car 5 is stopped, the start command circuit 28 is closed after the door is closed, and the (+)-start command circuit 28-
The time relay 30T is energized by the closed circuit between the contact 60c and the time relay 30T-(-), and when the car 5 moves out of the stop state, the normally closed contact 10b of the stop command switch 10 is activated. In order to close, this normally closed contact 10b and normally open contact 30Ta
to maintain self-preservation. Furthermore, by closing the normally closed contact 30Tb for timed return, the (+)-contact 30Tb is closed.
A closed circuit of Tb-contact 60d-contactor 30-(-) is formed, thereby energizing the operating contactor 30.

When the operating contactor 30 is energized, its normally open contacts 30a, 30b, 30c are closed and the three-phase induction motor 13 is connected to the inverter 23. Furthermore, by closing the normally open contact 30Tc, the bias pattern generation circuit 45 generates a bias pattern signal that provides low rotation. In accordance with this bias pattern signal, the inverter 23 generates a three-phase alternating current of low voltage and frequency. As a result, the three-phase induction motor 13 drives the hydraulic pump 12 at a low rotational speed corresponding to the amount of leakage of the hydraulic pump 12. At this time, the bias pattern signal alone will not raise the car 5.

After a certain period of time has passed after the normally open contact 30Tc is closed,
The delay circuit 40 operates to generate an output signal and supplies this to the upward running pattern generating circuit 41U, thereby outputting a running pattern signal from the upward running pattern generating circuit 41U. Therefore, the adder 46 outputs a pattern signal 46a that is the sum of the running pattern signal and the bias pattern signal, and is further controlled through the subtracter 48, the transfer circuit 49, the adder 50, the function generation circuit 51, and the sine wave generation circuit 52. By applying the signal 25a to the inverter 23, the electric motor 13 and the pump 12 are rotated at a speed corresponding to the upward travel pattern, and the hydraulic pump 12 sends out more pressure oil than the leakage amount. This hydraulic oil consists of: oil tank 15 - pipe 15a - hydraulic pump 1
The oil is sent into the cylinder 2 through the path 2-pipe 12a-electromagnetic switching valve 11-pipe 6-cylinder 2, and the car 5 is raised by an amount corresponding to the amount of oil. The hydraulic pump 12 is then accelerated and eventually reaches a constant speed. Thereafter, when the car 5 reaches a predetermined position before the destination floor where the call was received, the cam 8 activates the deceleration command switch 9. As a result, the pattern signal of the upward running pattern generation circuit 41U gradually decreases.
Eventually, it will start outputting a constant value. As a result, the car 5 continues to rise at a low speed, and when the cam 8 activates the stop command switch 10, the traveling pattern signal further decreases due to the opening of the normally open contact 30Tc.
It becomes zero. After that, after a certain period of time has passed, the normally open contact 30Tb opens, and the operating contactor 30 is deenergized.
Since the normally open contact 30d is opened, the bias pattern signal also decreases to zero. In addition, due to the deenergization of the operating contactor 30, its normally open contacts 30a to 30
c is opened, the inverter 23 is disconnected from the motor 1.
The power supply to 3 is cut off and it stops. At the same time, the check valve of the electromagnetic switching valve 11 closes and the car 5 remains stopped.

Next, we will discuss descending operation.

When the starting conditions are satisfied, the three-phase induction motor 13 is operated according to the bias pattern in the same manner as during the rising operation, and the pressure in the pipe 15a is increased. At the same time, the electromagnetic switching valve 11 is also energized and begins to open gradually, and the pipe 12
A and the pipe 6 communicate with each other, but since the discharge flow rate from the pump 12 is only to compensate for leakage, it is not supplied to the cylinder 2, and the car 5 does not move.

After that, an output signal is generated from the delay circuit 40,
By adding this to the downward travel pattern generation circuit 41D, a pattern signal is generated from the pattern generation circuit 41D. For this reason, adder 4
From 6 onwards, a pattern signal 46a for motor control is provided.
is output. Furthermore, the three-phase induction motor 13 is controlled according to the pattern signal and begins to gradually decelerate. With this deceleration, the hydraulic oil 3 is transferred to the cylinder 2.
The oil is returned to the oil tank 15 via the pipe 6 - electromagnetic switching valve 11 - pump 12 - tank 15 route. After the rotation of the three-phase induction motor 13 reaches zero, it rotates in reverse, and eventually reaches a constant speed. After that, when the cam 8 activates the deceleration command switch 9, deceleration starts,
Eventually, the speed becomes constant and slow. When the stop command switch 10 is activated in this state, the driving pattern signal decelerates and eventually becomes zero. At the same time, solenoid switching valve 1
Since the excitation coil 1 is demagnetized, the solenoid switching valve 1
1 gradually closes and prevents the hydraulic oil from flowing out from the cylinder 2, thereby stopping the car 5. Also,
After a certain period of time has elapsed, the bias pattern signal begins to decelerate and becomes zero.

In the above, it is assumed that, for example, when a descending operation command is issued, the coil 11a of the electromagnetic switching valve 11 cannot be excited due to a wire breakage or the like.

As mentioned above, the time relay 30T is activated when the starting conditions are met.
is energized, a bias pattern is generated, and the electric motor 13 rotates normally at a low speed. Since the hydraulic pressure at this time is sufficient to compensate for the amount of leakage, the pressure sensor 16 only increases to a pressure close to the jack pressure.
Therefore, the contact 16a of the pressure sensor 16 is never turned on. At the same time, an energizing command is given to the electromagnetic switching valve 11, but it does not open because the coil is disconnected.

Then, after a certain period of time, a running pattern signal is issued, and the electric motor 13 changes from normal rotation to zero, and then starts rotating in the reverse direction. When the rotation is reversed, the pump 12 acts to suck oil in the pipe 12a, but the amount of hydraulic oil in this pipe is very small and is immediately sucked out. Therefore, when the pump 12 continues to suck the inside of the pipe 12a, the pressure inside the pipe 12a becomes negative. The negative pressure at this time is the pressure sensor 16
is detected, and its contact 16a turns ON. Therefore, the (+)-contact 16a-time relay 60-
(-) circuit detects abnormal pressure time relay 60
is energized, normally open contact 60a is closed, and timed return contact 60b is opened. As a result, the time relay 60 is self-maintained, and the solenoid switching valve 18
The coil 18a is demagnetized, which opens the electromagnetic switching valve 18, and the branch passage 17 communicates with the pipe 12.
The a side is connected to the oil tank 15. Therefore, the oil in the oil tank 15 is supplied to the pipe 12a through the branch passage 17, the negative pressure in the pipe 12a is eliminated, and the oil due to the rotation of the hydraulic pump 12 is supplied to the branch passage 12a.
7 and is recirculated to the hydraulic tank 15.

Moreover, after energizing the abnormal pressure detection time relay 60,
After a certain period of time has elapsed, the time contacts 60a and 60d are opened, so the time relay 30T and the operating contactor 30 are deenergized, and the power supply to the motor 13 is cut off.
In addition, the coil 11a of the electromagnetic switching valve 11 is also demagnetized. Therefore, there is no suction from the hydraulic pump 12, and the negative pressure is eliminated. In addition, the start command circuit 2
8 is also cancelled. However, the electric motor 13 continues to rotate due to inertia, and the pump 12 also continues to pump.
Since the timed return contact 60b is still open, the circulation circuit is in communication and no negative pressure is generated. Thereafter, the electric motor 13 is stopped, the exciting coil 18a is also excited, and the branch passage 17 is cut off.

Next, a case where overpressure occurs will be explained. When the ascending command is issued, due to some abnormality, the solenoid switching valve 11
Suppose that the check valve of is in a state where it does not open.

When the starting condition is satisfied, the time relay 30T is energized, thereby generating a bias pattern, and the electric motor 13 rotates normally at a low speed. At this time, as described above, the pressure sensor 16 is only used to compensate for the leakage.
doesn't work.

After a certain period of time, when a driving pattern signal is generated,
The electric motor 13 gradually rotates at a high speed. Accordingly, the amount of discharge from the pump 12 to the pipe 12a increases, but since the check valve of the electromagnetic switching valve 11 does not open, the pressure inside the pipe 12a increases. and tube 12
When the pressure inside a becomes equal to or higher than the set pressure of the pressure sensor 16 (for example, 1.25 times the normal pressure), the pressure sensor 16 is activated and its contact 16a is closed. As a result, the abnormal pressure detection time relay 60 is energized, and when the time return contact 60b is opened, the coil 18a of the electromagnetic switching valve 18 is demagnetized, the branch passage 17 is opened, and the pipe 12 is
A is connected to the oil tank 15. For this reason, tube 1
The hydraulic pressure generated in 2a is transferred to the open branch passage 1.
7 to the oil tank 15, and suppresses the increase in pressure inside the pipe 12a. At the same time, the operating contactor 30 is deenergized by opening the contact point 60d, thereby cutting off the power supply to the electric motor 13, and the electric motor 13 gradually stops.

In the above embodiment, a case has been described in which negative pressure is generated at the time of startup, but negative pressure is also generated when a power outage occurs during descent. That is, if a power outage occurs during full-speed descent, the electromagnetic switching valve 11 will gradually close to suppress the flow rate, and the power supply to the electric motor 13 will also be cut off. However, even after the electromagnetic switching valve 11 closes, the pump 12 and the electric motor 13 continue to rotate due to inertial force, so negative pressure is generated as described above.

However, according to the circuit of this embodiment, when the excitation coil 18a is demagnetized due to a power outage, the branch passage 17 is brought into communication, so that generation of negative pressure can be similarly prevented.

Moreover, by providing this branch passage 17,
When the oil temperature drops, the electric motor is rotated to bypass and recirculate the oil, which can also serve as a circuit to raise the oil temperature. That is, when the oil temperature decreases, the oil temperature increase command relay (not shown) is energized, so its contact 7
0a and 70b are closed, and the time relay 30T and operation contactor 30 are energized to supply power to the electric motor 13, rotate it according to the upward running pattern, and cause the pump 12 to discharge oil. Further, by demagnetizing the coil 18a of the electromagnetic switching valve 18 by opening the contact 70c, the branch passage 17 is opened and the oil is circulated, so that the oil temperature can be increased due to the flow resistance. When the oil temperature rises to the set value, the contacts 70a and 70b open to stop the oil discharge from the pump 12, and the contact 70c excites the excitation coil 18a, so that the electromagnetic switching valve 18
is operated to close the branch passage 17.

In the above embodiment, the running pattern used when the oil temperature is increased is also used as the rising pattern, but a different pattern may be used. In addition, a pressure sensor that detects the pressure between the pump and the check valve is used to detect abnormal pressure, but it is also possible to indirectly detect abnormal pressure by detecting, for example, the opening of the electromagnetic switching valve or the disconnection of the coil. Any method is fine.

〔Effect of the invention〕

As explained above, the present invention controls the amount of hydraulic oil supplied and discharged to the hydraulic cylinder that raises and lowers the car using either a hydraulic pump connected to a speed controllable electric motor or a variable displacement hydraulic pump. death,
In a hydraulic elevator system that controls the speed of a car, an electromagnetic switching valve having a check valve that allows passage of hydraulic oil to the hydraulic cylinder is provided between the hydraulic pump and the hydraulic cylinder, and a non-returning valve between the hydraulic pump and the electromagnetic switching valve is provided. A branch passage is provided which branches from between the valves and communicates with the oil tank of the hydraulic elevator system, and an electromagnetic switching valve capable of bidirectional conduction is provided in this branch passage to normally shut off the branch passage and open the branch passage when excited;
A control circuit is provided which energizes the electromagnetic switching valve when abnormal pressure is detected in the hydraulic pipe line of the hydraulic elevator system and energizes the electromagnetic switching valve when the temperature of the hydraulic oil increases. This makes it possible to prevent negative pressure and excessive pressure from occurring in the pipeline with a single valve, and also allows the branch passage to be used as an oil temperature raising circuit when the oil temperature drops, as well as being simple and cost effective. It can be an inexpensive hydraulic elevator device.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an example of a hydraulic elevator system of the present invention, FIG. 2 is a block diagram showing details of the speed control circuit in FIG. 1, and FIG. 3 is a control circuit diagram in the present invention. 2... Cylinder, 5... Car, 9... Deceleration command switch, 10... Stop command switch, 11...
Electromagnetic switching valve having a check valve, 12... Hydraulic pump, 13... Electric motor, 14... Speed generator, 15
... Oil tank, 16 ... Pressure sensor, 17 ... Branch passage, 18 ... Solenoid switching valve, 21 ... Rectifier circuit, 23 ... Inverter, 24 ... Regeneration inverter, 25 ... Speed control device, 28 ...Start command circuit, 30T...Timed relay, 30...Driving contactor, 60...Abnormal pressure detection timed relay, 70a,
70b, 70c...Oil temperature rise command relay contacts.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Control the supply and discharge flow of hydraulic oil to the hydraulic cylinders that raise and lower the car using either a hydraulic pump connected to a speed controllable electric motor or a variable displacement hydraulic pump, and control the speed of the car. In the hydraulic elevator system, an electromagnetic switching valve having a check valve that allows passage of the hydraulic oil to the hydraulic cylinder is provided between the hydraulic pump and the hydraulic cylinder, and the electromagnetic switching valve has a reverse connection between the hydraulic pump and the electromagnetic switching valve. A branch passage is provided between the stop valves and communicated with the oil tank of the hydraulic elevator system, and the branch passage is provided with a bidirectional conductive electromagnetic switching valve that normally shuts off the branch passage and opens the branch passage when energized. and a control circuit that energizes the electromagnetic switching valve when abnormal pressure is detected in the hydraulic pipe line of the hydraulic elevator system and energizes the electromagnetic switching valve when the temperature of the hydraulic oil increases. Hydraulic elevator equipment.