Elevator apparatus having rescue operation controller

In an elevator apparatus, a rescue operation for a car is performed by a rescue operation controller. The rescue operation controller obtains a rescue operation voltage value and applies a voltage having the rescue operation voltage value to a brake coil in response to a signal from a speed detector at a time of the rescue operation for the car. The rescue operation voltage value is a value of the voltage necessary to reduce braking force of a brake device to move the car by using a state of imbalance between the car and a counterweight.

TECHNICAL FIELD

The present invention relates to an elevator apparatus capable of performing a rescue operation for a car which is stopped between floors.

BACKGROUND ART

In a conventional rescue operation device in case of failure for an elevator, when a failure occurs in an elevator controller, a brake is released by brake releasing means. As a result, a car is moved due to imbalance between the car and a counterweight. At this time, a travel distance or a speed of the car is detected. Base on results of detection, the brake is operated (for example, see Patent Document 1).

Patent Document 1: JP 2005-247512 A

DISCLOSURE OF THE INVENTION

Problem to be Solved by the Invention

With the conventional rescue operation device in case of failure as described above, however, a sudden acceleration state, a sudden deceleration state, and a stop state are repeated a plurality of times until the arrival of the car at a landing. Therefore, there is fear in that a passenger in the car is made uncomfortable. Moreover, the car is stopped a plurality of times until the arrival at the landing, and hence a time required to complete a rescue operation becomes disadvantageously long.

The present invention is devised to solve the problems described above, and has an object of providing an elevator apparatus capable of performing a rescue operation within a short period of time while preventing ride comfort from being deteriorated.

Means for Solving the Problems

An elevator apparatus according to the present invention includes: a car and a counterweight, each being suspended by a suspending member in a hoistway; a brake device including a brake coil for canceling braking force by excitation thereof, the brake device being for braking the car against a state of imbalance between the car and the counterweight; a speed detector for detecting a speed of the car; and a rescue operation controller for obtaining a rescue operation voltage value corresponding to a value of a voltage necessary to reduce the braking force of the brake device to move the car by using the state of the imbalance between the car and the counterweight and for applying a voltage having the rescue operation voltage value to the brake coil in response to a signal from the speed detector at a time of a rescue operation for the car.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, preferred embodiments of the present invention are described with reference to the drawings.

First Embodiment

FIG. 1is a configuration diagram illustrating an elevator apparatus according to a first embodiment of the present invention. In the drawing, a car1and a counterweight2are suspended by a main rope3corresponding to a suspending member in a hoistway and are raised and lowered by a driving force of a hoisting machine4. The hoisting machine4includes a drive sheave5around which the main rope3is looped, a motor6for rotating the drive sheave5, and braking means7for braking the rotation of the drive sheave5.

The braking means7includes a brake wheel8which is rotated integrally with the drive sheave5and a brake device9for braking the rotation of the brake wheel8. As the brake wheel8, a brake drum, a brake disc, or the like is used. The drive sheave5, the motor6, and the brake wheel8are provided on the same shaft.

The brake device9includes a plurality of brake linings10which are moved into contact with and away from the brake wheel8, a plurality of brake springs (not shown) for pressing the brake linings10against the brake wheel8, and a plurality of electromagnetic magnets for separating the brake linings10away from the brake wheel8against the brake springs. Each of the brake magnets includes a brake coil (electromagnetic coil)11which is excited by energization.

A current is made to flow through the brake coils11to excite the electromagnetic magnets. As a result, an electromagnetic force for canceling the braking force of the brake device9is generated to separate the brake linings10from the brake wheel8. On the other hand, by de-energizing the brake coils11, the electromagnetic magnets are de-excited. By a spring force of the brake springs, the brake linings10are pressed against the brake wheel8.

The brake device9brakes the car1against a state of imbalance between the car1and the counterweight2. Moreover, the braking force of the brake device9is controlled by controlling a voltage applied to the brake coils11.

A hoisting machine encoder12corresponding to a speed detector for generating a signal according to a rotational speed of a rotary shaft of the motor6, that is, a rotational speed of the drive sheave5is provided to the hoisting machine4. A weighing device20for generating a signal according to a load in the car is provided to the car1.

In an upper part of the hoistway, a speed governor13is provided. The speed governor13includes a governor sheave14and a governor encoder15corresponding to a speed detector for generating a signal according to a rotational speed of the governor sheave14. A governor rope16is looped around the governor sheave14. Both ends of the governor rope16are connected to the car1. A lower end of the governor rope16is looped around a tension sheave17provided in a lower part of the hoistway.

When the car1is raised or lowered, the movement is transmitted through the governor rope16to the governor sheave14to rotate the governor sheave14at a speed according to the speed of the car1. As a result, the governor encoder15generates a signal according to the speed of the car1.

Drive of the hoisting machine4is controlled by the elevator controller18. Specifically, the ascent and descent of the car1is controlled by the elevator controller18. The brake device9is controlled by a brake controller19. The signals from the elevator controller18, the weighing device20, the hoisting machine encoder12, and the governor encoder15are input to the brake controller19.

When the car1is stopped between floors due to some failure, the brake controller19executes a rescue operation for the car1in response to a rescue operation command from the elevator controller18. Specifically, the brake controller19functions as a rescue operation controller.

Moreover, at the time of the rescue operation for the car1, the brake controller19obtains a rescue operation voltage value corresponding to a value of a voltage to be applied to the brake coils11to intermittently apply the obtained voltage to the brake coils11. The rescue operation voltage value is a value of the voltage required to reduce the braking force of the brake device9to move the car1by using the state of imbalance between the car1and the counterweight2. In other words, the rescue operation voltage value is a voltage value which is necessary and sufficient (almost minimum) to move the car1and is suitable for suppressing vibrations when the car1is moved.

FIG. 2is a block diagram illustrating the brake controller19illustrated inFIG. 1. The brake controller19includes a rescue operation command detecting section21, a weighing signal detecting section22, a speed signal processing section23, and a brake signal calculating section24. The rescue operation command detecting section21detects a rescue operation command signal from the elevator controller18. The weighing signal detecting section22detects a weighing signal from the weighing device20. The speed signal processing section23calculates the speed of the car1based on at least any one of the signal from the hoisting machine encoder12and that from the governor encoder15.

Upon detection of the rescue operation command signal by the rescue operation command detecting section21, the brake signal calculating section24obtains the amount of imbalance between the car1and the counterweight2based on the weighing signal from the weighing device20to calculate the rescue operation voltage value based on the amount of imbalance. A relation between the amount of imbalance and the rescue operation voltage value optimal for the amount of imbalance is pre-registered in the form of an expression or a table in the brake controller19. Such a relation between the amount of imbalance and the rescue operation voltage value is obtained in advance for each elevator apparatus by calculation or experiment.

Moreover, the brake signal calculating section24calculates a target speed of the car1at the time of the rescue operation based on the rescue operation command signal. Further, the brake signal calculating section24compares the speed of the car1obtained by the speed signal processing section23and the target speed with each other at the time of the rescue operation. The brake signal calculating section24excites the brake coils11when the speed of the car1is less than the target speed and stops the excitation of the brake coils11when the speed of the car1is equal to or higher than the target speed. At this time, a value of the voltage for exciting the brake coils11is determined as the rescue operation voltage value.

As described above, the brake signal calculating section24outputs a brake control signal for turning ON/OFF an excitation voltage to each of the brake coils11to allow the speed of the car1, which is obtained by the speed signal processing section23, to follow the target speed.

Here, the brake controller19includes a computer including a computation processing section (CPU, and the like), a storage section (ROM, RAM, hard disk, and the like), and a signal input/output section. The functions of the brake controller19can be realized by computation processing performed by the computer. In the storage section of the computer, programs (software) for realizing the functions are stored. The brake controller19may be constituted by an electric circuit for processing analog signals.

FIG. 3is a flowchart illustrating an operation of the brake controller19illustrated inFIG. 1.FIG. 4is a timing chart illustrating a relation between the rescue operation command, the brake command, a pull-in voltage command, and the speed of the car1in the elevator apparatus illustrated inFIG. 1. The pull-in voltage command is a command of a value of the voltage to be applied to the brake coils11.

The brake controller19monitors whether or not the rescue operation command has been detected (Step51). Upon detection of the rescue operation command, the weighing signal is detected to obtain the amount of imbalance between the car1and the counterweight2(Step S2). Then, based on the amount of imbalance, a computation for obtaining the rescue operation voltage value (control pull-in voltage computation) is executed (Step S3).

When the rescue operation voltage value is determined, the application of the voltage to the brake coils11is started (Step S4, at a time t1inFIG. 4) and a target speed V0is set (Step S5). After that, it is confirmed whether or not the rescue operation command has been detected (Step S6). If the rescue operation command has been detected, the speed V of the car1is compared with the target speed V0(Step S7). Then, when the speed of the car1is less than the target speed, the brake coils11are excited (Step S8). When the speed of the car1is equal to or higher than the target speed, the excitation of the brake coils11is stopped (Step S9).

The operation as described above is repeated. When the car1is moved to a landing floor and the rescue operation command is no longer detected, the voltage applied to the brake coils11is removed (Step S10, at a time t2inFIG. 4). The braking force of the brake device9is increased to stop the car1, thereby terminating the rescue operation.

Although a running time of the car1is illustrated shorter inFIG. 4than it actually is for simplicity, the number of times of ON/OFF of the brake command is actually larger than that illustrated inFIG. 4because one pulse of the brake command is, for example, about 5 msec.

In the elevator apparatus as described above, at the time of the rescue operation for the car1, the rescue operation voltage value corresponding to the value of the voltage which is necessary to reduce the braking force of the brake device9to move the car1by using the state of imbalance between the car1and the counterweight2is obtained. The voltage having the rescue operation voltage value is applied to the brake coils11according to the encoder signal. Therefore, the car1can be operated at a low speed to follow the target speed without repeating acceleration/deceleration and stop a plurality of times. Accordingly, the rescue operation can be performed within a short period of time while ride comfort is prevented from being deteriorated.

Moreover, at the time of the rescue operation for the car1, the brake controller19obtains the amount of imbalance between the car1and the counterweight2based on the signal from the weighing device20. Based on the amount of imbalance, the rescue operation voltage value is obtained. Therefore, the amount of cancellation of the brake, which is necessary to cause the car1to run by using the state of imbalance, can be easily estimated. Thus, the rescue operation with vibrations suppressed can be performed without limiting the state of imbalance with which the rescue operation is possible.

Specifically, as the amount of imbalance increases, the rescue operation voltage value is reduced. As a result, if the amount of imbalance is large, the car1is not started at a large acceleration rate. Therefore, the rescue operation with vibrations suppressed can be performed.

Further, at the time of the rescue operation for the car1, the brake controller19excites the brake coils11when the speed of the car1is less than the target speed and stops the excitation of the brake coils11when the speed of the car1becomes equal to or higher than the target speed. Therefore, the car1can be caused to run to follow a safe target speed suitable for the rescue operation.

The weighing device20can be provided at any location as long as the signal according to the load in the car can be generated, and therefore, is not limited to that mounted to the car1.

Second Embodiment

Next,FIG. 5is a block diagram illustrating the brake controller19for the elevator apparatus according to a second embodiment of the present invention. In the drawing, the brake controller19includes the rescue operation command detecting section21, the speed signal processing section23, a starting detecting section25, and the brake signal calculating section24. The starting detecting section25detects starting of the car1based on the speed of the car1, which is obtained by the speed signal processing section23.

The brake signal calculating section24gradually increases the value of the voltage to be applied to the brake coils11while monitoring the starting of the car1at the time of the rescue operation for the car1. The value of the voltage when the car1is started is used as the rescue operation voltage value. The remaining configuration is the same as that of the first embodiment.

FIG. 6is a flowchart illustrating the operation of the brake controller19illustrated inFIG. 5.FIG. 7is a timing chart illustrating the relation between the rescue operation command, the brake command, the pull-in voltage command, and the speed of the car1in the elevator apparatus according to the second embodiment.

The brake controller19monitors whether or not the rescue operation command has been detected (Step S1). Upon detection of the rescue operation command, an initial voltage is applied to the brake coils11(Step S11, at a time t4inFIG. 7) and the target speed V0is set (Step S5). Then, it is confirmed whether or not the starting of the car1has been detected (Step S12). A value of the initial voltage is set to a value small enough to prevent the car1from being started even when the amount of imbalance between the car1and the counterweight2is the largest.

The brake controller19gradually increases the voltage applied to the brake coils11until the car1is started (Step S14). Then, when the starting of the car1is detected (at a time t5inFIG. 7), a voltage value at that time is set as the rescue operation voltage value (Step S13).

Upon determination of the rescue operation voltage value, it is confirmed whether or not the rescue operation command has been detected (Step S6). If the rescue operation command has been detected, the speed V of the car1is compared with the target speed V0(Step S7). If the speed of the car1is less than the target speed, the brake coils11are excited (Step S8). If the speed of the car1is equal to or higher than the target speed, the excitation of the brake coils11is stopped (Step S9).

The operation as described above is repeated. When the car1is moved to a landing floor and the rescue operation command is no longer detected, the voltage applied to the brake coils11is removed (Step S10, at a time t6inFIG. 4). The braking force of the brake device9is increased to stop the car1, thereby terminating the rescue operation.

In the elevator apparatus as described above, the rescue operation voltage value can be determined without using the weighing device20. Thus, the rescue operation with vibrations suppressed can be performed without limiting the state of imbalance with which the rescue operation is possible.

Third Embodiment

Next,FIG. 8is a timing chart illustrating the relation between the brake command and the pull-in voltage command at the time of rescue operation in the elevator apparatus according to a third embodiment of the present invention. The brake controller19excites the brake coils11when the speed of the car1is less than the target speed at the time of the rescue operation for the car1and reduces a time ratio for exciting the brake coils11when the speed of the car1becomes equal to or higher than the target speed.

More specifically, the brake controller19applies the voltage to the brake coils11with a predetermined cycle within a time period in which the speed of the car1is higher than the target speed and the brake command is OFF. An application time and a cycle of application of the voltage in the time period in which the brake command is OFF are set sufficiently shorter than an average length of the time period in which the brake command is OFF. The remaining structure is the same as that of the first or second embodiment.

In the elevator apparatus as described above, a reduction of the current flowing through the brake coils11is delayed in the time period in which the brake command is OFF. Therefore, a sudden increase of a brake torque can be prevented to further suppress the vibrations at the time of the rescue operation.

Fourth Embodiment

Next,FIG. 9is a timing chart illustrating the relation between the brake command and the pull-in voltage command at the time of rescue operation in the elevator apparatus according to a fourth embodiment of the present invention. The brake controller19excites the brake coils11when the speed of the car1is less than the target speed at the time of the rescue operation for the car1and sets the voltage, at which the brake coils11are excited, not to zero but to a predetermined voltage value lower than the rescue operation voltage value when the speed of the car1becomes equal to or higher than the target speed.

In this example, when the speed of the car1becomes higher than the target speed, the brake controller19sets the voltage, at which the brake coils11are excited, to less than 50% and equal to or larger than 20% of the rescue operation voltage value. The remaining structure is the same as that of the first or second embodiment.

In the elevator apparatus as described above, a reduction of the current flowing through the brake coils11is delayed in the time period in which the brake command is OFF. Therefore, a sudden increase of a brake torque can be prevented to further suppress the vibrations at the time of the rescue operation.

Although the brake device9including two sets of the brake linings10and the brake coils11is described in the above-mentioned example, the number of sets of the brake linings10and the brake coils11may be one or equal to or larger than three.

Moreover, although the brake device9is provided to the hoisting machine4in the above-mentioned example, the brake device9is not limited thereto. For example, the brake device9may be, for example, a car brake mounted to the car1, a rope brake for gripping the main rope3, or the like.

Further, although the brake controller19also serves as the rescue operation controller in the above-mentioned example, the rescue operation controller may be provided independently of the brake controller19for controlling the brake device9at the time of a normal operation.