CN115867505B - Elevator with a motor - Google Patents

Abstract

Provided is an elevator capable of suppressing the braking distance of a car in emergency stop. An elevator (1) is provided with a slip detection unit (16), a sheave speed detection unit (9), and a brake control unit (17). A slip detection unit (16) detects the slip of the main rope (5) relative to the sheave (13) of the hoisting machine (4). When the slip detection unit (16) detects the occurrence of slip during an emergency stop, the brake control unit (17) compares the speed of the sheave (13) detected by the sheave speed detection unit (9) at the time point of the period from the start of the emergency stop to the start of slip with a preset threshold value. When the speed of the sheave (13) exceeds a threshold value, a brake control unit (17) controls the brake (8) according to a control method for eliminating the slip of the main rope (5). When the speed of the sheave (13) does not exceed the threshold value, the brake control unit (17) controls the brake (8) in accordance with a control method that controls the braking force of the brake (8) so that the sheave (13) decelerates at a set deceleration.

Description

elevator

Technical Field

The present disclosure relates to elevators.

Background Art

Patent document 1 discloses an example of an elevator. In the elevator, the speed of the car suspended by the main rope and the speed of the sheave around which the main rope is wound are detected. The control unit controls the braking force applied to the sheave. When the elevator stops in an emergency, if the difference between the speed of the sheave and the speed of the car is below a threshold, the control unit applies the full braking force. On the other hand, if the difference between the speed of the sheave and the speed of the car exceeds the threshold due to slippage of the main rope, the control unit applies a braking force weaker than the full braking force.

Prior Art Literature

Patent Literature

Patent Document 1: Japanese Patent Application Publication No. 2004-231355

Summary of the invention

Problems to be solved by the invention

However, if the braking force is reduced to suppress the slipping of the main ropes depending on the situation such as the speed of the car when the slipping of the main ropes occurs, the braking distance of the car may become longer.

The present disclosure relates to solving the above-mentioned problems. The present disclosure provides an elevator capable of suppressing the braking distance of a car during an emergency stop.

Solutions to Solve Problems

The elevator of the present disclosure includes: a brake for braking a sheave around which a main rope is wound in a hoisting machine for raising and lowering a car in a hoisting path, the main rope suspending the car in the hoisting path; a slip detector for detecting whether the main rope has slipped relative to the sheave; a sheave speed detector for detecting the speed of the sheave; and a brake control unit for comparing the speed of the sheave detected by the sheave speed detector at a predetermined arbitrary reference time point during a period from the start of the emergency stop to the start of the slip with a predetermined speed threshold value when the slip detector detects the occurrence of the slip during an emergency stop, and controlling the brake according to a slip elimination control method for eliminating the slip between the sheave and the main rope when the speed at the reference time point exceeds the speed threshold, and controlling the brake according to a braking force control method for controlling the braking force of the brake so that the sheave decelerates at a set deceleration when the speed at the reference time point does not exceed the speed threshold.

The elevator of the present disclosure includes: a brake for braking a sheave around which a main rope for suspending the car on the hoisting path is wound in a hoisting machine for raising and lowering the car on the hoisting path; a slip detector for detecting whether the main rope has slipped relative to the sheave; a car speed detector for detecting the speed of the car; a sheave speed detector for detecting the speed of the sheave; and a brake control unit for comparing the speed of the car detected by the car speed detector at a predetermined arbitrary reference time point during the period from the start of the emergency stop to the start of the slip with a predetermined speed threshold value when the slip detector detects the occurrence of the slip during an emergency stop, and controlling the brake according to a slip elimination control method for eliminating the slip between the sheave and the main rope when the speed at the reference time point exceeds the speed threshold, and controlling the brake according to a braking force control method for controlling the braking force of the brake so that the sheave decelerates at a set deceleration when the speed at the reference time point does not exceed the speed threshold.

Effects of the Invention

According to the elevator according to the present disclosure, the braking distance of the car during an emergency stop can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an elevator according to Embodiment 1. FIG.

FIG. 2 is a diagram showing an example of a speed waveform at the time of an emergency stop of the car according to the first embodiment.

FIG. 3 is a diagram showing an example of a speed waveform at the time of an emergency stop of the car according to the first embodiment.

FIG. 4 is a diagram showing an example of a speed waveform at the time of an emergency stop of the car according to the first embodiment.

FIG. 5 is a diagram showing an example of a speed waveform at the time of an emergency stop of the car according to the first embodiment.

FIG. 6 is a flowchart showing an example of the operation of the elevator according to the first embodiment.

FIG. 7 is a hardware configuration diagram of a main part of the elevator according to the first embodiment.

FIG8 is a block diagram of an elevator according to the second embodiment.

DETAILED DESCRIPTION

The embodiment of the present disclosure will be described with reference to the accompanying drawings. In each of the drawings, the same or corresponding parts are denoted by the same reference numerals, and repeated descriptions are appropriately simplified or omitted.

Implementation method 1.

FIG. 1 is a configuration diagram of an elevator 1 according to the first embodiment.

The elevator 1 is installed in a building having a plurality of floors, for example. In the building, there is provided an elevator path 2 for the elevator 1. The elevator path 2 is a space passing through a plurality of floors.

The elevator 1 includes a car 3 , a hoisting machine 4 , a main rope 5 , a counterweight 6 , a speed governor 7 , a brake 8 , a sheave speed detector 9 , a car speed detector 10 , a safety switch 11 , and a control device 12 .

The car 3 is arranged in the hoistway 2. The car 3 is a device for transporting users and the like between multiple floors. The hoist 4 is a device for raising and lowering the car 3 arranged in the hoistway 2. The hoist 4 includes a motor (not shown) that generates a driving force and a sheave 13 that is driven and rotated by the motor. The main rope 5 is wound around the sheave 13. The main rope 5 suspends the car 3 in the hoistway 2 on one side of the sheave 13. The main rope 5 suspends the counterweight 6 in the hoistway 2 on the other side of the sheave 13. The counterweight 6 is a device that balances the load applied to both sides of the sheave 13 through the main rope 5 between the car 3 and the hoist 4.

The speed governor 7 is a device for limiting the speed of the car 3. The speed governor 7 includes a speed governor rope 14 and a speed governor pulley 15. The speed governor rope 14 is a rope installed on the car 3. The speed governor pulley 15 is a pulley around which the speed governor rope 14 is wound. The speed governor pulley 15 is rotated by the speed governor rope 14 that moves in conjunction with the travel of the car 3. The speed governor 7 limits the speed of the car 3 according to the rotation speed of the speed governor pulley 15.

The brake 8 is a device for braking the sheave 13. The brake 8 is, for example, a disc brake, a drum brake, or other brakes with a movable portion. Normally, when in a braking state, the brake 8 applies a braking force to the sheave 13 that can keep the car 3 and the counterweight 6 in a stationary state. The braking force is, for example, a friction force that suppresses the rotation of the sheave 13, or a thrust force that generates the friction force. On the other hand, the brake 8 does not hinder the rotation of the sheave 13 when in a released state.

The sheave speed detection unit 9 is a part that detects the speed of the sheave 13. The speed of the sheave 13 detected by the sheave speed detection unit 9 is, for example, the speed of the outer periphery of the sheave 13. The sheave speed detection unit 9 has, for example, an encoder that detects the rotation amount of the sheave 13. The sheave speed detection unit 9 may also be equipped with a function of converting the rotation amount of the sheave 13 into the rotation speed of the sheave 13 or the speed of the outer periphery of the sheave 13.

The car speed detection unit 10 is a part that detects the speed of the car 3. The speed of the car 3 detected by the car speed detection unit 10 is, for example, the travel speed of the car 3 in the vertical direction. The car speed detection unit 10 has, for example, an encoder that detects the amount of rotation of the governor pulley 15. The car speed detection unit 10 may also be equipped with a function of converting the amount of rotation of the governor pulley 15 into the travel speed of the car 3. In addition, the car speed detection unit 10 may also detect the speed of the car 3 based on the detection results of a position sensor, a speed sensor, or an acceleration sensor provided in the car 3. In addition, the car speed detection unit 10 may also detect the speed of the car 3 by detecting the speed of the main rope 5 or the counterweight 6 that moves in conjunction with the car 3.

The safety switch 11 is provided in the lifting path 2. The safety switch 11 is arranged at the upper end and the lower end of the lifting path 2. The safety switch 11 is a switch for detecting, for example, that the car 3 continues to travel after passing the landing position of the uppermost floor or the lowermost floor. When the safety switch 11 is operated, for example, the elevator 1 may not travel but remain on standby until it is inspected by a maintenance person or the like. In this case, there is a possibility that a user riding in the car 3 may be trapped.

The control device 12 is a device for controlling the operation of the elevator 1. The operation of the elevator 1 includes, for example, the travel of the car 3 and the operation of the brake 8. The operation of the brake 8 includes an emergency stop. The emergency stop is an operation that stops the traveling car 3 due to the input of an emergency stop signal, the detection of the occurrence of an emergency stop event, or the occurrence of a power outage. The emergency stop is initiated, for example, by detecting some abnormality during the travel of the car 3. The abnormality that initiates the emergency stop is detected by an abnormality detector (not shown) provided in the elevator 1. The abnormality detector is, for example, a safety device provided in the elevator 1. The control device 12 includes a slip detector 16 and a brake control unit 17.

The slip detector 16 is a part that detects whether there is a slip between the main rope 5 and the sheave 13. Here, at the time of emergency stop, the brake 8 applies a braking force to the sheave 13 that rotates together with the main rope 5. At this time, the main rope 5 may slip relative to the sheave 13 depending on the position in the hoistway of the car 3 linked to the main rope 5, the travel direction, the travel acceleration and the mass, the load in the car 3 that varies due to the number of passengers and the equipment carried by the car 3, the shape of the rope groove of the sheave 13, the friction coefficient between the main rope 5 and the sheave 13, and the braking force of the brake 8. The slip detector 16 detects whether the main rope 5 slips during such an emergency stop. The slip detector 16 detects whether the main rope 5 slips, for example, by detecting the relative movement of the main rope 5 relative to the outer peripheral portion of the sheave 13 in the circumferential direction. The slip detector 16 detects the presence of slip, for example, as follows.

The slip detector 16 calculates the difference between the speed of the car 3 and the speed of the sheave 13 detected by the car speed detector 10 and the sheave speed detector 9, respectively, as the relative speed of the main rope 5 with respect to the sheave 13. When the calculated relative speed exceeds a preset threshold value, the slip detector 16 detects the occurrence of slip of the main rope 5. On the other hand, when the calculated relative speed is lower than a preset threshold value, the slip detector 16 detects the elimination of slip of the main rope 5.

In addition, when there is a resonance system from the car 3 to the car speed detector 10, the slip detector 16 may apply an inverse model filter of the mechanical characteristics from the car 3 to the car speed detector 10 to the output of the car speed detector 10 to remove the influence of the mechanical characteristics. The slip detector 16 may calculate the relative speed with respect to the output of the sheave speed detector 9 after performing the processing. In addition, the slip detector 16 may calculate the relative speed of the main rope 5 with respect to the sheave 13 by using the output of the car speed detector 10 to which the mechanical characteristics filters from the position from the hoist 4 to the car 3 and from the car 3 to the car speed detector 10 are applied and the speed of the car 3. Thus, since the influence caused by the expansion and contraction of the main rope 5 other than the slip of the main rope 5 is removed, the relative speed of the main rope 5 with respect to the sheave 13 can be calculated with high accuracy. Therefore, since the threshold value for detecting the presence or absence of slip can be reduced, the accuracy of detecting the slip of the main rope 5 can be improved.

The brake control unit 17 is a part that controls the operation of the brake 8. The brake control unit 17 switches between a plurality of control modes to control the operation of the brake 8. The plurality of control modes include a braking force control mode and a slip elimination control mode.

The braking force control method is a control method for controlling the braking force of the brake 8 so that the sheave 13 decelerates at a set deceleration. The set deceleration is a constant deceleration pre-set between the first deceleration _a1 and the second deceleration _a2 . Here, the deceleration is an acceleration that reduces the absolute value of the speed. In this example, the absolute value of the first deceleration _a1 is greater than the absolute value of the second deceleration _a2 . In addition, the control of the brake 8 under the braking force control method can also be performed based on the speed of the sheave 13 detected by the sheave speed detection unit 9. In addition, since the speed of the car 3 is roughly the same as the speed of the sheave 13 when no slip occurs, the control of the brake 8 under the braking force control method can also be performed based on the deceleration of the sheave 13 estimated from the speed of the car 3 detected by the car speed detection unit 10.

The first deceleration _a1 is a deceleration at which it is expected that no slip will occur between the main rope 5 and the sheave 13 in the case of an emergency stop at a deceleration smaller in absolute value than the first deceleration _a1 . The first deceleration _a1 is calculated in advance based on the predicted value of the traction capacity of the hoist 4. The predicted value of the traction capacity is, for example, the difficulty of the main rope 5 sliding relative to the sheave 13 calculated based on the specifications or design values such as the shape and material of the sheave 13 and the main rope 5 of the hoist 4. In the predicted value of the traction capacity, the reduction of local friction conditions such as wear between the sheave 13 and the main rope 5 is not considered. In addition, in the calculation of the first deceleration _a1 , the running direction of the car 3 and the load conditions where the main rope 5 is likely to slip are considered. The conditions where slip is likely to occur include, for example, the conditions when ascending under no load or descending under the maximum load. The first deceleration _a1 is, for example, a deceleration calculated in advance as the upper limit of no slip when the reduction of local friction conditions is not considered.

The second deceleration _a2 is a deceleration at which it is expected that the car 3 will not travel to the position where the safety switch 11 is arranged when the car 3 is stopped urgently at a deceleration whose absolute value is greater than the second deceleration _a2 . The second deceleration _a2 is calculated in advance based on the weight of the car 3, the counterweight 6, the main rope 5 and the sheave 13, and the specifications or design values of the rated speed of the car 3. In the calculation of the second deceleration _a2 , the travel direction of the car 3 and the load conditions where the travel amount of the car 3 increases are considered. Here, the travel amount is the distance from the landing position of the terminal floor such as the uppermost floor or the lowermost floor to the position where the car 3 passes the landing position and stops. The conditions where the travel amount of the car 3 increases include, for example, the conditions when the car 3 ascends without load or descends under the maximum load. The second deceleration _a2 is, for example, a lower limit deceleration calculated in advance so that the safety switch 11 does not operate when the overshoot of the control of the brake 8 is not considered. Here, the overshoot of the control of the brake 8 means that the braking force is too large relative to the command.

By controlling the operation of the brake 8 by the brake control unit 17 according to the braking force control mode with the deceleration between the first deceleration _a1 and the second deceleration _a2 as the set deceleration, the occurrence of slippage of the main rope 5 and the occurrence of user entrapment can be suppressed even in the case of an emergency stop. However, slippage of the main rope 5 may occur due to a decrease in local friction conditions or overshoot of the control of the brake 8. Therefore, the brake control unit 17 switches to the slip elimination control mode according to the conditions such as the speed of the car 3 when slippage occurs, so as to prevent the braking distance of the car 3 from becoming longer.

The slip elimination control mode is a control mode for eliminating the slip between the sheave 13 and the main rope 5. The state in which the slip between the sheave 13 and the main rope 5 is eliminated is a state in which the relative speed of the main rope 5 and the sheave 13 becomes 0 and they move as one. In the slip elimination control mode, the brake control unit 17 controls the braking force of the brake 8, for example, in such a manner that the speed of the sheave 13 follows the speed of the car 3. The brake control unit 17 controls the deceleration of the sheave 13 by adjusting the magnitude of the braking force applied to the sheave 13, for example, in such a manner that the difference between the speed of the car 3 detected by the car speed detection unit 10 and the speed of the sheave 13 detected by the sheave speed detection unit 9 becomes smaller. Thus, the slip of the main rope 5 is eliminated, that is, the traction is restored. Preferably, the brake control unit 17 controls the brake 8 while adjusting the braking force in such a manner that the brake 8 is kept in the braking state and the state does not change to the released state in the slip elimination control mode. Alternatively, the brake control unit 17 may release the brake 8 until the slip detector 16 detects the elimination of the slip. In addition, any method of controlling the brake 8 in the slip elimination control mode may be used as long as the slip elimination state can be established.

Next, an example of the braking distance of the car 3 during an emergency stop will be described using FIG. 2 and FIG. 3 .

FIG. 2 and FIG. 3 are diagrams showing examples of speed waveforms during an emergency stop of the car 3 according to the first embodiment.

The horizontal axis of Fig. 2 and Fig. 3 represents time. The vertical axis of Fig. 2 and Fig. 3 represents the speed of the car 3 and the sheave 13. In Fig. 2 and Fig. 3, the solid line represents the speed waveform of the car 3. In Fig. 2 and Fig. 3, the dotted line represents the speed waveform of the sheave 13. In addition, for the purpose of explanation, in Fig. 2 and Fig. 3, an example of the speed waveform in the case where the brake torque is simplified in a step-like manner is shown.

FIG. 2 shows an example in which the brake control unit 17 does not switch the control method.

When the abnormality detector of the elevator 1 detects an abnormality, a detection signal is input to the control device 12. At this time, the control device 12 performs an emergency stop of the car 3. The control device 12 outputs a power stop command to the hoist 4. The hoist 4 stops the rotation drive of the sheave 13 based on the input command. In addition, for example, when the detection signal is input to the control device 12, the brake control unit 17 starts the emergency stop of the car 3. Point A in Figure 2 corresponds to the moment when the brake control unit 17 starts the emergency stop of the car 3.

When the emergency stop is started, the brake control unit 17 controls the brake 8 according to the braking force control method. The brake control unit 17 outputs the brake control command to the brake 8. The brake 8 starts braking the sheave 13 after the brake control command is input. Here, there is a delay time due to the operation of the movable part of the brake 8 and the like from the input of the command to the brake 8 to the generation of the braking force. Point B in FIG. 2 corresponds to the moment when the brake 8 generates the braking force after the delay time from the input of the command.

During the delay time when the brake 8 generates the braking force from point A to point B, the car 3 and the sheave 13 are accelerated or decelerated due to the unbalanced torque of the car 3 and the counterweight 6. In this example, the situation where the car 3 is accelerated is shown as a situation where the braking distance of the car 3 becomes longer. The situation where the car 3 is accelerated due to the unbalanced torque is, for example, when rising under no load or descending under maximum load. The car 3 increases at a constant acceleration during the delay time from point A to point B. In addition, in fact, sometimes the acceleration is not constant due to the imbalance of the rope, etc., but in this embodiment, a simplified model assuming that the acceleration is constant is used for explanation.

When the sheave 13 is decelerated by the braking force of the brake 8 after the delay time, the sheave 13 and the car 3 start to decelerate. Here, the speed of the sheave 13 and the car 3 just before the deceleration is called the maximum speed. When the sheave 13 and the main rope 5 are decelerated by the braking force of the brake 8, the main rope 5 slips relative to the sheave 13. FIG2 shows an example of the case where slip occurs just after the brake 8 generates the braking force. That is, point B in FIG2 corresponds to the start of slip of the main rope 5.

When the main rope 5 slips, the slip detector 16 detects the slip of the main rope 5. The slip detector 16 outputs a detection signal to the brake control unit 17. When the detection signal is input from the slip detector 16, the brake control unit 17 detects the speed of the car 3 or the sheave 13 at the reference time point by the car speed detector 10 or the sheave speed detector 9. The reference time point is any preset arbitrary time point from the start of the emergency stop to the start of the slip. Since the main rope 5 has not slipped at the reference time point, the speed of the car 3 and the speed of the sheave 13 linked to the main rope 5 are equal. Therefore, the brake control unit 17 can use at least one of the speed of the car 3 detected by the car speed detector 10 and the speed of the sheave 13 detected by the sheave speed detector 9 as the speed at the reference time point. When the detection signal is input, the brake control unit 17 determines whether the speed at the reference time point exceeds the speed threshold value V _lim . The speed threshold value V _lim is a value of the speed of the car 3 which is set in advance so as to suppress the braking distance of the car 3 during an emergency stop.

When the detection signal is input from the slip detector 16, the brake control unit 17 of this example uses the point B where the slip starts as a reference time point to determine whether the speed _VB at the point B exceeds the speed threshold value _Vlim . For example, the brake control unit 17 may use the detection value of the car speed detector 10 or the sheave speed detector 9 when the detection signal is input as the speed _VB at the point B. Alternatively, the brake control unit 17 may calculate the speed _VB at the point B when the slip starts by interpolation or extrapolation based on the time series data of the detection value of the car speed detector 10 or the sheave speed detector 9. In the example of FIG2, the content of the present embodiment is not applied, and the speed waveform is shown when the main rope 5 continues to slip during the emergency stop operation. In addition, compared with the speed waveform when the content of the present embodiment is applied and _VB does not exceed the speed threshold value _Vlim , that is, when the main rope 5 continues to slip, the speed waveform of FIG2 has the same outline, the speeds at points A and B are small, and the time between BC becomes short.

After the main rope 5 slips, the sheave 13 and the car 3 decelerate at different decelerations. In this example, since the brake control unit 17 maintains the braking force control mode, the sheave 13 stops at point C1 after decelerating at a constant deceleration. In addition, the car 3 stops at point F1 after decelerating at a constant deceleration due to the friction of the main rope 5 sliding relative to the sheave 13.

When the car 3 stops, the brake control unit 17 makes a stop determination of the car 3. The stop determination of the car 3 is made, for example, based on the speed of the car 3 detected by the car speed detection unit 10. The brake control unit 17 makes a stop determination of the car 3, for example, when the absolute value of the speed of the car 3 is lower than a preset threshold value. Alternatively, the brake control unit 17 may make a stop determination of the car 3 when the absolute value of the speed of the car 3 is lower than a preset threshold value of the speed and the time rate of change of the speed is lower than a preset threshold value of the rate of change. In addition, for example, when the main rope 5 does not slip relative to the sheave 13, the brake control unit 17 may make a stop determination of the car 3 based on the speed of the sheave 13 detected by the sheave speed detection unit 9. When the main rope 5 does not slip, the speed of the car 3 and the speed of the sheave 13 are the same, so the brake control unit 17 can make a stop determination of the car 3 using the speed of the sheave 13 in the same way as the stop determination using the speed of the car 3. In addition, the brake control unit 17 can also perform the stop judgment of the car 3 according to other methods. After determining that the car 3 has stopped, the brake control unit 17 applies a braking force to the sheave 13 that can keep the car 3 and the counterweight 6 in a static state as usual. On the other hand, when it is determined that the car 3 has not stopped, the brake control unit 17 continues to control the brake 8 during emergency stop.

The braking distance _S1 of the car 3 in the case of Fig. 2 corresponds to the area of the portion between the speed waveform shown by the solid line and the horizontal axis. Therefore, the estimated value of the braking distance _S1 is expressed by the following formula (1).

Here, S _AB represents the distance traveled by the car 3 from point A to point B. _{a rope} is a predicted value of the deceleration of the car 3 when the main rope 5 decelerates while sliding relative to the sheave 13. The acceleration a _rope corresponds to the inclination of the line segment connecting point B and point F1 in FIG. 2 . Since the acceleration a _rope is an acceleration that reduces the absolute value of the speed of the car 3, it takes a negative value when the travel direction of the car 3 is a positive direction.

In addition, the distance S _AB can also be calculated by, for example, the following formula (2).

Here, _ak represents the predicted value of the idling acceleration of the car 3 due to the unbalanced torque. The acceleration _ak corresponds to the inclination of the line segment connecting point A and point B in FIG. 2 . Since the acceleration _ak increases the absolute value of the speed of the car 3, it takes a positive value when the traveling direction of the car 3 is a positive direction. _T1 represents the predicted value of the time between point A and point B until the brake 8 generates a braking force. The predicted value _T1 includes the predicted time required for the state transition of the brake 8 from the released state to the braked state.

In addition, the brake control unit 17 may use point A when the emergency stop starts as a reference time point and control the brake 8 based on the speed _VA at point A. In this case, in equations (1) and (2), the value of the speed _VB calculated from the speed _VA at point A using the following equation (3) may be used.

_VB ＝ _{VA + akT1} …(3)

In addition, similarly to the case of the speed _VB , the brake control unit 17 can use at least one of the speed of the car 3 detected by the car speed detection unit 10 and the speed of the sheave 13 detected by the sheave speed detection unit 9 as the speed _VA . In addition, the brake control unit 17 can also control the brake 8 based on the speed at the reference time point by using any time point from point A when the emergency stop starts to point B when the main rope 5 starts to slip as a reference time point. In this case, the value of the speed _VB calculated from the speed at the reference time point in the same way as in formula (3) can also be used.

On the other hand, FIG. 3 shows an example in which the brake control unit 17 switches the control method.

FIG. 3 shows an example in which slip occurs immediately after the brake 8 generates braking force, similarly to FIG. 2 .

The brake control unit 17 of this example determines whether the speed _VB at the reference point B exceeds the speed threshold _Vlim when receiving the detection signal from the slip detector 16. In this example, the speed _VB exceeds the speed threshold _Vlim . At this time, the brake control unit 17 switches the control mode from the braking force control mode to the slip elimination control mode.

Here, there is a delay time from when the slip occurs to when the slip detector 16 outputs the detection signal. During the delay time, the sheave 13 and the car 3 decelerate at different decelerations. Since the brake control unit 17 has not switched the control mode from the braking force control mode during the delay time, the sheave 13 decelerates at a constant deceleration. In addition, the car 3 decelerates at a constant deceleration due to the friction of the main rope 5 sliding relative to the sheave 13.

Then, after a delay time caused by a detection delay of the slip detection, the brake 8 starts braking the sheave 13 according to the slip elimination control method. Point C2 in FIG. 3 corresponds to the moment when the braking force of the brake 8 is changed from the braking force control method by switching to the slip elimination control method after a delay time has passed since the occurrence of the slip. Here, the delay time between point B and point C includes the detection delay of the slip and the control response delay of the brake 8. According to the slip elimination control method, the brake 8 is controlled to eliminate the slip of the main rope 5. For example, the brake control unit 17 controls the braking force provided by the brake 8 to the sheave 13 so that the speed of the sheave 13 follows the speed of the car 3. Point D in FIG. 3 corresponds to the moment when the slip of the main rope 5 is eliminated according to the slip elimination control method. Here, there is a delay time in the period from the elimination of the slip to the detection by the slip detector 16, similar to the detection of the occurrence of the slip. During this delay time, the brake 8 provides the braking force based on the slip elimination control method to the sheave 13. Point E in FIG. 3 corresponds to the timing at which the brake 8 generates the braking force based on the braking force control method after a delay time has passed since the slip is eliminated.

In the example of FIG. 3 , the braking force based on the slip elimination control method is smaller than the braking force based on the braking force control method so that the slip of the main rope 5 generated in the braking force control method can be eliminated. Therefore, during the delay time from point D to point E when the brake 8 generates the braking force, the car 3 is accelerated or decelerated according to the unbalanced torque of the car 3 and the counterweight 6. In this example, the case where the car 3 is accelerated as a condition where the braking distance of the car 3 becomes longer is shown. The car 3 increases in speed at a constant acceleration during the delay time from point D to point E.

After the delay time, the sheave 13 and the car 3 start to decelerate at point E. At this time, since the slip of the main rope 5 is eliminated, the main rope 5 and the sheave 13 move as one. Therefore, the car 3 and the sheave 13 stop at point F2 after being decelerated at a constant deceleration equal to each other.

The braking distance _S2 of the car 3 in the case of Fig. 3 corresponds to the area of the portion between the speed waveform shown by the solid line and the horizontal axis. Therefore, the estimated value of the braking distance _S2 is expressed by the following formula (4).

Here, a _c is the command value of the deceleration after the traction is restored, that is, after the slip of the main rope 5 is eliminated. The acceleration a _c corresponds to the inclination of the line segment connecting the point E and the point F2 in FIG. 3. Since the acceleration a _c is the acceleration that reduces the absolute value of the speed of the car 3, it takes a negative value when the travel direction of the car 3 is set to the positive direction. a _tr is the predicted value of the acceleration of the car 3 during the delay time after the traction is restored. The acceleration a _tr corresponds to the inclination of the line segment connecting the point D and the point E in FIG. 3. Since the acceleration a _tr is the acceleration that increases the absolute value of the speed of the car 3, it takes a positive value when the travel direction of the car 3 is set to the positive direction. In addition, when the slip state is eliminated by releasing the brake 8, the acceleration a _tr is equal to the idling acceleration _ak . _{T 2} is the predicted value of the time between the point B and the point D until the traction is restored. The prediction value _T2 includes the delay time of the detection of the occurrence of slip by the slip detector 16. In addition, when the state of the brake 8 changes from the braking state to the released state in the switching from the braking force control mode to the slip elimination control mode, the prediction value _T2 includes the prediction time required for the state transition. _T3 is a prediction value of the time between point D and point E until the brake 8 generates the braking force based on the braking force control mode. The prediction value _T3 includes the delay time of the detection of the elimination of slip by the slip detector 16. In addition, when the state of the brake 8 changes from the released state to the braking state in the switching from the slip elimination control mode to the braking force control mode, the prediction value _T3 includes the prediction time required for the state transition.

In addition, the slip of the main rope 5 is caused by a local reason such as a decrease in the friction coefficient or a temporary reason such as an overshoot of the brake control, and therefore, the command value _ac of the deceleration after the traction is restored is set to a deceleration within a normal range where slip does not occur. In addition, the absolute value of the command value _ac is set to a value greater than the absolute value of the predicted value _arope of the deceleration when slip occurs. The value of the command value _ac is, for example, the value of the set deceleration. By making the absolute value of the command value _ac sufficiently greater than the absolute value of the predicted value _arope , even when the car 3 is accelerated to restore the traction, the influence of the acceleration on the braking distance can be eliminated.

In this example, the predicted values _ak , a _rope , a _tr , T ₁ , T ₂ and T ₃ used in equations (1) to (4) are values preset or calculated based on, for example, the specifications or design values of the elevator 1. The command value a _c is a preset value.

Next, an example of the speed threshold value V _lim will be described using FIG. 4 and FIG. 5 .

FIG. 4 and FIG. 5 are diagrams showing examples of speed waveforms during an emergency stop of the car 3 according to the first embodiment.

The horizontal axis of Fig. 4 and Fig. 5 represents time. The vertical axis of Fig. 4 and Fig. 5 represents the speed of the car 3. In Fig. 4 and Fig. 5, the solid line represents the speed waveform when the brake control unit 17 switches the control method. In Fig. 4 and Fig. 5, the dotted line represents the speed waveform when the brake control unit 17 does not switch the control method. In addition, as in Fig. 2 and Fig. 3, Fig. 4 and Fig. 5 show an example of a simplified speed waveform when the brake torque is increased in a step-like manner.

FIG. 4 shows an example in which a braking distance _S1 when the brake control unit 17 does not switch the control method is equal to a braking distance _S2 when the control method is switched.

The speed threshold value V _lim is set as the speed at the reference time point when the braking distance S ₁ and the braking distance S ₂ are equal. In this example, since point B is set as the reference time point, the speed threshold value V _lim is set as the speed at point B when the braking distance S ₁ and the braking distance S ₂ are equal. The speed threshold value V _lim obtained by setting S ₁ = S ₂ in equations (1) to (4) is represented by predicted values _ak , a _rope , a _tr , T ₁ , T ₂ and T ₃ , and command value _ac and the like. In this example, the braking distance S ₁ and the braking distance S ₂ or the speed threshold value V _lim is calculated based on the pre-set operating conditions for evaluation. The operating conditions for evaluation include conditions such as the size of the load inside the car 3 and the travel direction of the car 3. The operating conditions for evaluation may also include conditions such as the acceleration of the car 3 determined according to the position of the car 3.

Since the braking distance of the car 3 corresponds to the area of the portion between the speed waveform and the horizontal axis, the difference between the braking distance _S1 and the braking distance _S2 corresponds to the difference between the area _α1 and the area _α2 . Here, the area _α1 is the area of the portion where the speed waveform of the dashed line is larger than the speed waveform of the solid line. The area _α2 is the area of the portion where the speed waveform of the solid line is larger than the speed waveform of the dashed line. In FIG. 4 , since the braking distance _S1 and the braking distance _S2 are equal, the area _α1 and the area _α2 are equal.

Fig. 5 shows an example in which the speed _VB at the reference time point B exceeds the speed threshold value _Vlim . In this example, the value of the speed _VB is greater than the value of the speed threshold value _Vlim by the speed difference ΔV.

The speed threshold value V _lim is the speed at the reference time point B when the braking distance S ₁ and the braking distance S ₂ are equal. Therefore, in the area above the single-dot chain line in FIG. 5 , the area of the portion where the speed waveform of the solid line is larger than the speed waveform of the dashed line is equal to the area of the portion where the speed waveform of the dashed line is larger than the speed waveform of the solid line. Therefore, the area α ₁ is larger than the area α ₂ by the amount of the area below the single-dot chain line. Therefore, the braking distance S ₁ is larger than the braking distance S ₂ .

Similarly, when the speed V _B at the reference time point B is lower than the speed threshold V _lim (not shown), the area α ₁ is smaller than the area α _2. Therefore, the braking distance S ₁ is smaller than the braking distance S ₂ .

The brake control unit 17 can control the brake 8 so that the car 3 stops at the shorter braking distance between the braking distance _S1 and the braking distance _S2 by switching the control mode based on the comparison between _the speed _VB at the reference time point B and the speed threshold value Vlim. In addition, the brake control unit 17 may use any time point from the point A when the emergency stop starts to the point B when the main rope 5 starts to slip as the reference time point. In this case, the brake control unit 17 can also control the brake 8 so that the car 3 stops at the short braking distance by switching the control mode based on the comparison result of the speed threshold value set similarly to the reference time point and the speed at the reference time point.

Next, an example of the operation of the elevator 1 will be described using FIG. 6 .

FIG. 6 is a flowchart showing an example of the operation of the elevator 1 according to the first embodiment.

FIG. 6 shows an example of the operation of the brake control unit 17 related to the emergency stop.

In step S1, when the emergency stop is started, the brake control unit 17 controls the braking of the brake 8 according to the braking force control method. Then, the operation of the elevator 1 proceeds to step S2.

In step S2, the brake control unit 17 determines whether the slip detector 16 detects slip based on the presence or absence of the detection signal, etc. If the determination result is yes, the operation of the elevator 1 proceeds to step S3. If the determination result is no, the operation of the elevator 1 proceeds to step S6.

In step S3, the brake control unit 17 detects the speed V _B at the reference time point B, using the time when the slip starts as a reference time point. Then, the operation of the elevator 1 proceeds to step S4.

In step S4, the brake control unit 17 determines whether the speed _VB exceeds the speed threshold value _Vlim . If the determination result is YES, the operation of the elevator 1 proceeds to step S5. If the determination result is NO, the operation of the elevator 1 proceeds to step S6.

In step S5, the brake control unit 17 controls the braking of the brake 8 according to the slip elimination control method. Then, the operation of the elevator 1 proceeds to step S2.

In step S6, the brake control unit 17 controls the braking of the brake 8 according to the braking force control method. Then, the operation of the elevator 1 proceeds to step S7.

In step S7, the brake control unit 17 determines whether the car 3 is stopped. If the determination result is no, the operation of the elevator 1 proceeds to step S2. If the determination result is yes, the operation of the elevator 1 regarding the emergency stop is completed.

In addition, the slip detector 16 may detect whether the main rope 5 has slipped based on the change in the apparent inertial mass of the sheave 13 as follows. When there is no slip of the main rope 5, the apparent inertial mass of the sheave 13 is the inertial mass obtained by adding the inertial mass of the car 3 and the counterweight 6 to the inertial mass of the sheave 13 itself. On the other hand, when there is slip of the main rope 5, the apparent inertial mass of the sheave 13 is only the inertial mass of the sheave 13 itself. Therefore, even when the torque applied to the sheave 13 and the braking force applied to the sheave 13 by the brake 8 are the same, the deceleration of the sheave 13 will change depending on the presence or absence of slip. If there is slip of the main rope 5, the deceleration of the sheave 13 becomes larger, and therefore, the slip detector 16 may detect the occurrence of slip when the deceleration of the sheave 13 exceeds a preset threshold value. Here, the slip detector 16 may also calculate the deceleration of the sheave 13 based on, for example, the speed of the sheave 13 detected by the sheave speed detector 9. The slip detector 16 may also perform slip detection using the following information: the acceleration of the deceleration or acceleration of the sheave 13 or the car 3 based on the speed information of at least one of the speeds detected by the sheave speed detector 9 and the car speed detector 10; and the deceleration command value of the braking force control method. The slip detector 16 may also perform slip elimination detection based on the following information: the acceleration of the deceleration or acceleration of the sheave 13 or the car 3 based on the speed information of at least one of the speeds detected by the sheave speed detector 9 and the car speed detector 10; and the control state of the brake 8. The slip detector 16 may also combine a plurality of means for detecting whether the main rope 5 is slipped.

In the present disclosure, the case where the car 3 is accelerated relative to the traveling direction due to the unbalanced torque of the car 3 and the counterweight 6 is used as an example for explanation, but the contents of the present disclosure can also be applied to the case of deceleration. In addition, in the case of deceleration, although the speed of the sheave 13 and the car 3 just before the deceleration is started is not the maximum speed, it is referred to as the maximum speed in the present disclosure for the sake of convenience.

As described above, the elevator 1 according to Embodiment 1 includes the brake 8, the slip detector 16, the car speed detector 10, and the brake control unit 17. The main rope 5 for suspending the car 3 on the hoistway 2 is wound around the sheave 13 of the hoist 4. The hoist 4 causes the car 3 to rise and fall in the hoistway 2. The brake 8 brakes the sheave 13 in the hoist 4. The slip detector 16 detects whether the main rope 5 has slipped relative to the sheave 13. The car speed detector 10 detects the speed of the car 3. When the slip detector 16 detects the occurrence of slip during an emergency stop, the brake control unit 17 compares the speed of the car 3 detected by the car speed detector 10 at a reference time point with a preset speed threshold value. The reference time point is any preset time point in the period from the start of the emergency stop to the start of slip.

In addition, the elevator 1 involved in Embodiment 1 may include both the car speed detection unit 10 and the sheave speed detection unit 9, or may include the sheave speed detection unit 9 instead of the car speed detection unit 10. The sheave speed detection unit 9 detects the speed of the sheave 13. At this time, when the slip detector 16 detects the occurrence of slip at the time of emergency stop, the brake control unit 17 compares the speed of the car 3 detected by the car speed detection unit 10 or the speed of the sheave 13 detected by the sheave speed detection unit 9 at the reference time point with a preset speed threshold value.

When the speed at the reference time point for comparison exceeds the speed threshold, the brake control unit 17 controls the brake 8 according to the slip elimination control method. The slip elimination control method is a control method for eliminating the slip between the sheave 13 and the main rope 5. On the other hand, when the speed at the reference time point for comparison does not exceed the speed threshold, the brake control unit 17 controls the brake 8 according to the braking force control method. The braking force control method is a control method for controlling the braking force so that the sheave 13 decelerates at a set deceleration.

According to this configuration, the control method of the brake 8 after the main rope 5 starts to slip is selected so that the braking distance of the car 3 becomes shorter, corresponding to the speed of the car 3 or the sheave 13 at the reference time point during the period from the start of the emergency stop to the start of the slip. Therefore, in the case where the car 3 is accelerated due to the delay time of the operation of the brake 8 and the delay time of the slip detection, the braking distance of the car 3 during the emergency stop can be suppressed. In addition, since the control method is selected based on the speed at the reference time point before the start of the slip, the brake control unit 17 can quickly control the brake 8 according to the selected control method after the occurrence of the slip is detected.

Here, if the relative speed of the main rope 5 and the sheave 13 increases, the friction between the main rope 5 and the sheave 13 when the main rope 5 slips decreases. Therefore, when the braking force control method is maintained even after the occurrence of slip is detected, the deceleration of the car 3 varies until the car 3 stops. During the period from the start of slip to the stop of the sheave 13, the absolute value of the deceleration of the car 3 gradually decreases from the deceleration at the start of slip. Then, after the sheave 13 stops, the deceleration of the car 3 gradually increases because the relative speed decreases. Then, at the latest until the car 3 stops, the absolute value of the deceleration of the car 3 decreases to the deceleration at the start of slip. Therefore, the speed waveform that takes into account the change in the deceleration of the car 3 becomes a waveform on the upper side of the speed waveform that is decelerated constantly while maintaining the deceleration at the start of slip in FIG. 2 and the like. Therefore, the braking distance _S1 calculated by the formula (1) becomes the braking distance calculated under the minimum condition when the control of the brake 8 by the slip elimination control method is not performed. Since the brake control unit 17 controls the brake 8 by the slip elimination control method when the braking distance _S2 is shorter than the braking distance _S1 , the braking distance of the car 3 does not increase due to the switching of the control method.

In addition, the brake control unit 17 uses the time point when the main rope 5 starts to slip as a reference time point. As a result, since the influence of the braking distance before the time point when the sliding starts is eliminated in the evaluation of the braking distance _S1 and the braking distance _S2 , the speed threshold value _Vlim is not affected by the movement of the car 3 before the main rope 5 actually starts to slip. Therefore, even when the main rope 5 does not start to slip after the brake 8 just starts to apply the braking force to the sheave 13, it is easy to calculate the speed threshold value _Vlim and compare it with the speed threshold value _Vlim .

In addition, the brake control unit 17 uses the time point when the emergency stop starts as the reference time point. Thus, since the reference time point and the speed threshold can be compared before the main rope 5 starts to slip, the brake control unit 17 can control the brake 8 more quickly according to the selected control method after detecting the occurrence of slip.

In addition, the brake control unit 17 controls the brake 8 according to the braking force control mode before the slip detector 16 detects the occurrence of slip during emergency stop. In addition, the brake control unit 17 controls the brake 8 according to the braking force control mode when the slip detector 16 detects the elimination of slip. Thus, when the main rope 5 does not slip, the car 3 can be decelerated according to a large deceleration such as a set deceleration. Therefore, the braking distance of the car 3 becomes shorter.

In addition, the brake control unit 17 uses the speed of the car 3 or the sheave 13 at the reference time point when the estimated value _S1 of the braking distance and the estimated value _S2 of the braking distance are equal as the speed threshold value _Vlim , and switches the slip elimination control mode and the braking force control mode. The braking distance _S1 is an estimated value of the braking distance of the car 3 when the brake 8 is controlled according to the braking force control mode when the slip detector 16 detects the occurrence of slip. The braking distance _S2 is an estimated value of the braking distance of the car 3 when the brake 8 is controlled according to the slip elimination control mode when the slip detector 16 detects the occurrence of slip. In this way, since the speed threshold value _Vlim is set based on the estimated value _S1 of the braking distance and the estimated value _S2 of the braking distance, the braking distance of the car 3 during emergency stop can be more reliably suppressed.

The speed threshold value _{Vlim is} calculated based on information including a predicted value a _rope of deceleration, a predicted value a _tr of acceleration, a set deceleration, a predicted value of a delay time of detecting the presence or absence of slip by the slip detector 16, and a predicted value of a delay time of the state transition of the brake 8. The predicted value a _rope is a predicted value of the deceleration of the car 3 when the brake 8 is controlled according to the braking force control method when the slip detector 16 detects the occurrence of slip. The predicted value a _tr is a predicted value of the acceleration of the car 3 when the brake 8 is controlled according to the slip elimination control method when the slip of the main rope 5 relative to the sheave 13 is eliminated. The predicted value of the delay time of detection and the predicted value of the delay time of the state transition are included in the predicted values T ₁ , T ₂ , and T ₃ of the delay time. Thus, the speed threshold value _Vlim can be calculated based on known information before the slip is detected. Therefore, after the occurrence of slip is detected, the brake control unit 17 can control the brake 8 more quickly according to the selected control method.

In addition, the brake control unit 17 may control the braking force of the brake 8 so that the brake 8 does not change from the braking state to the released state in the slip elimination control mode. Thus, since there is no time for the state change of the brake 8, the braking delay time of the brake 8 is shortened. Therefore, the time for the car 3 to accelerate immediately after the traction is restored can be suppressed.

In addition, the brake control unit 17 controls the brake 8 by using a deceleration whose absolute value is smaller than the first deceleration _a1 and whose absolute value is larger than the second deceleration _a2 as a set deceleration. The first deceleration _a1 is a deceleration of the car 3 calculated in advance based on the predicted value of the traction capacity of the hoist 4 as the upper limit deceleration at which the main rope 5 does not slip relative to the sheave 13. The second deceleration _a2 is a deceleration of the car 3 calculated in advance as the lower limit deceleration at which the safety switch 11 provided in the hoistway 2 does not operate. Thereby, the occurrence of slip of the main rope 5 and the occurrence of being trapped due to the operation of the safety switch 11 can be suppressed.

In addition, part or all of the slip detector 16 and the brake control unit 17 may be mounted on a device external to the control device 12 .

Next, an example of the hardware configuration of the elevator 1 will be described using FIG. 7 .

FIG. 7 is a hardware configuration diagram of a main part of the elevator 1 according to the first embodiment.

Each function of the elevator 1 can be realized by a processing circuit. The processing circuit has at least one processor 100a and at least one memory 100b. The processing circuit can have both the processor 100a and the memory 100b and at least one dedicated hardware 200, or can have at least one dedicated hardware 200 as a substitute for the processor 100a and the memory 100b.

When the processing circuit includes a processor 100a and a memory 100b, each function of the elevator 1 is realized by software, firmware, or a combination of software and firmware. At least one of the software and firmware is described as a program. The program is stored in the memory 100b. The processor 100a realizes each function of the elevator 1 by reading and executing the program stored in the memory 100b.

The processor 100a is also called a CPU (Central Processing Unit), a processing device, an arithmetic device, a microprocessor, a microcomputer, or a DSP. The memory 100b is composed of a nonvolatile or volatile semiconductor memory such as a RAM, a ROM, a flash memory, an EPROM, or an EEPROM.

When the processing circuit has dedicated hardware 200, the processing circuit is implemented by, for example, a single circuit, a complex circuit, a programmed processor, a parallel programmed processor, an ASIC, an FPGA, or a combination thereof.

Each function of the elevator 1 can be implemented separately by the processing circuit. Alternatively, each function of the elevator 1 can also be implemented collectively by the processing circuit. Regarding each function of the elevator 1, a part can be implemented by the dedicated hardware 200, and the other part can be implemented by software or firmware. In this way, the processing circuit implements each function of the elevator 1 through the dedicated hardware 200, software, firmware, or a combination thereof.

Implementation method 2.

In Embodiment 2, points different from the example disclosed in Embodiment 1 are described in detail. With respect to features not described in Embodiment 2, any features of the example disclosed in Embodiment 1 can be adopted.

FIG8 is a diagram showing the configuration of the elevator 1 according to the second embodiment.

The elevator 1 includes a load detection unit 18. The load detection unit 18 is a part that detects the load inside the car 3. The load detection unit 18 is provided, for example, at the lower part of the car 3 or at the end of the main rope 5 installed on the car 3. Normally, the load detection unit 18 is used, for example, to compensate for the unbalanced torque that changes due to the load of the car 3 and to detect overload of the car 3.

The control device 12 includes a direction detection unit 19. The direction detection unit 19 is a part that detects the travel direction of the ascending or descending car 3. The direction detection unit 19 determines ascending or descending based on the sign of the speed detected by the sheave speed detection unit 9 or the car speed detection unit 10. In this example, the brake control unit 17 controls the brake 8 using the start of slip as a reference time point.

The load of the car 3 affects the torque applied to the sheave 13 via the main rope 5. In addition, the direction in which the brake torque is applied varies depending on the travel direction of the car 3. Therefore, the condition that the main rope 5 does not slip varies depending on the load and travel direction of the car 3. Therefore, the maximum deceleration at which the main rope 5 starts to slip varies depending on the load and travel direction of the car 3. The condition that the main rope 5 does not slip is expressed by the following formula (5).

Here, Γ represents the traction coefficient. exp represents an exponential function. k represents the groove coefficient of the sheave 13. The groove coefficient is a coefficient determined according to the shape of the rope groove of the sheave 13, etc. μ is the friction coefficient between the main rope 5 and the sheave 13. The product kμ of the groove coefficient k and the friction coefficient μ represents the apparent friction coefficient between the main rope 5 and the sheave 13. θ represents the winding angle of the main rope 5 about the sheave 13. Ten1 represents the tension on the car 3 side viewed from the sheave 13. Ten2 represents the tension on the counterweight 6 side viewed from the sheave 13. Slippage of the main rope 5 occurs when the tension ratio on the right side of the formula (5) exceeds the traction coefficient Γ.

In addition, the equation of motion about the rotation axis of the sheave 13 when the main rope 5 does not slip is expressed by the following equation (6).

Here, M _tm represents an equivalent mass corresponding to the inertia of the sheave 13. a _tm represents the deceleration of the sheave 13. F _BK represents a force obtained by converting the brake torque into a force in the rotation direction of the sheave 13. The sign of the force F _BK is set to be negative when the car 3 is ascending and positive when the car 3 is descending.

Since the condition for the main rope 5 to just start sliding is that the tension ratio is equal to the traction coefficient in formula (5), the deceleration a _tm when starting to slide can be calculated by applying the tension that satisfies this condition to formula (6). Here, the values of the tension Ten1 and the tension Ten2 can be calculated corresponding to the pulling using, for example, the mass of the winch 4, the counterweight 6, and the ropes, and the inertial mass and mass of the pulleys. Here, the ropes include, for example, the main rope 5, the compensating rope, the control cable, and the governor rope 14. The pulleys include, for example, the deflector pulley, the return pulley, and the compensating pulley.

The brake control unit 17 calculates the deceleration at the start of sliding corresponding to the load of the car 3 and the travel direction of the car 3. The brake control unit 17 uses the deceleration to calculate the speed threshold V _lim by, for example, the same calculation method as in Embodiment 1. The brake control unit 17 performs brake control at the time of emergency stop based on the calculated speed threshold V _lim . Thus, since a control method corresponding to the load condition is selected, the braking distance can be further shortened.

The brake control unit 17 may calculate and update the speed threshold V _lim every time the load and travel direction of the car 3 change. Alternatively, the brake control unit 17 may update the speed threshold V _lim by referring to a table of speed thresholds V _lim calculated in advance for each load and travel direction of the car 3 .

As described above, the elevator 1 according to the second embodiment includes the direction detection unit 19 and the load detection unit 18. The direction detection unit 19 detects the travel direction of the car 3. The load detection unit 18 detects the load inside the car 3. The speed threshold value _Vlim is calculated based on information including the travel direction of the car 3 detected by the direction detection unit 19 and the load of the car 3 detected by the load detection unit 18.

According to this configuration, the speed threshold value V _lim is set according to the operating conditions such as the load and the travel direction of the car 3. Thus, a control method of the brake 8 that shortens the braking distance of the car 3 is selected according to the operating conditions.

In addition, the speed threshold value V _lim may be calculated based on information including only one of the travel direction of the car 3 detected by the direction detection unit 19 and the load of the car 3 detected by the load detection unit 18. When the detection value of the travel direction of the car 3 is not included in the information for calculating the speed threshold value V _lim , the speed threshold value V _lim may be calculated based on the travel direction of the car 3 set in advance for evaluation. In addition, when the detection value of the load of the car 3 is not included in the information for calculating the speed threshold value V _lim , the speed threshold value V _lim may be calculated based on the load of the car 3 set in advance for evaluation.

Industrial Applicability

The elevator involved in the present disclosure can be applied to a building with multiple floors.

Description of Reference Numerals

1 elevator, 2 lifting path, 3 car, 4 winch, 5 main rope, 6 counterweight, 7 speed governor, 8 brake, 9 pulley speed detection unit, 10 car speed detection unit, 11 safety switch, 12 control device, 13 pulley, 14 speed governor rope, 15 speed governor pulley, 16 sliding detection unit, 17 brake control unit, 18 load detection unit, 19 direction detection unit, 100a processor, 100b memory, 200 dedicated hardware.

Claims (13)

1. An elevator, wherein,

The elevator is provided with:

a brake that brakes a sheave around which a main rope suspending the car from a hoistway is wound in a hoist that lifts the car from the hoistway;

A slip detection unit that detects whether or not the main rope slips relative to the sheave;

a sheave speed detecting unit that detects a speed of the sheave; and

And a brake control unit that compares a speed of the sheave detected by the sheave speed detection unit at a predetermined arbitrary reference point in a period from when the emergency stop starts to when the slip detection unit detects the slip, with a predetermined speed threshold value, and when the speed at the reference point exceeds the speed threshold value, controls the brake according to a slip cancellation control method for canceling the slip between the sheave and the main rope, and when the speed at the reference point does not exceed the speed threshold value, controls the brake according to a braking force control method for controlling the braking force of the brake so that the sheave decelerates at a set deceleration.

2. The elevator as claimed in claim 1, wherein,

The brake control unit switches the slip cancellation control method and the braking force control method using the speed of the sheave at the reference point, which is the speed threshold value, and the estimated value of the braking distance of the car when the brake is controlled according to the braking force control method when the slip detection unit detects the occurrence of slip and the estimated value of the braking distance of the car when the brake is controlled according to the slip cancellation control method when the slip detection unit detects the occurrence of slip are equal to each other.

3. An elevator, wherein,

The elevator is provided with:

a brake that brakes a sheave around which a main rope suspending the car from a hoistway is wound in a hoist that lifts the car from the hoistway;

A slip detection unit that detects whether or not the main rope slips relative to the sheave;

a car speed detecting unit that detects a speed of the car;

a sheave speed detecting unit that detects a speed of the sheave; and

And a brake control unit that compares a speed of the car detected by the car speed detection unit at a predetermined arbitrary reference point in a period from when the emergency stop starts to when the slip detection unit detects the occurrence of the slip, with a predetermined speed threshold value, and when the speed at the reference point exceeds the speed threshold value, controls the brake according to a slip cancellation control method for canceling the slip between the sheave and the main rope, and when the speed at the reference point does not exceed the speed threshold value, controls the brake according to a braking force control method for controlling the braking force of the brake so that the sheave decelerates at a set deceleration.

4. The elevator as claimed in claim 3, wherein,

The brake control unit switches the slip cancellation control method and the braking force control method using the speed of the car at the reference point, which is the speed threshold value, and the estimated value of the braking distance of the car when the brake is controlled according to the braking force control method when the slip detection unit detects the occurrence of slip and the estimated value of the braking distance of the car when the brake is controlled according to the slip cancellation control method when the slip detection unit detects the occurrence of slip are equal to each other.

5. The elevator according to any one of claims 1 to 4, wherein,

In the brake control unit, the reference time point is set in advance as a time point at which the main rope starts to slide.

6. The elevator according to any one of claims 1 to 4, wherein,

In the brake control unit, the reference time point is set in advance as a time point at which the emergency stop starts.

7. The elevator according to any one of claims 1 to 4, wherein,

The brake control unit controls the brake according to the braking force control method before the slip detection unit detects the occurrence of slip at the time of emergency stop.

8. The elevator according to any one of claims 1 to 4, wherein,

The brake control unit controls the brake according to the braking force control method when the slip detection unit detects the slip cancellation.

9. The elevator according to any one of claims 1 to 4, wherein,

The brake control unit switches between the slip cancellation control mode and the braking force control mode based on the speed threshold value calculated based on information including:

A predicted value of the idling acceleration of the car due to unbalanced torque;

The reference time point;

A predicted value of deceleration of the car when the slip detection unit detects the occurrence of slip, and the brake control unit does not switch a control mode of the brake and the main rope decelerates while slipping with respect to the sheave;

a predicted value of acceleration of the car when the brake is controlled according to the slip elimination control method at the time of elimination of slip of the main rope relative to the sheave;

Setting deceleration in the braking force control mode;

A predicted value of a delay time of detection of whether or not the slip detection unit has slipped; and

Predicted value of delay time of state transition of the brake.

10. The elevator as claimed in claim 9, wherein,

The elevator includes a direction detecting section for detecting a traveling direction of the car,

The brake control unit switches the slip cancellation control system and the braking force control system based on the speed threshold value calculated based on information including the traveling direction of the car detected by the direction detection unit.

11. The elevator as claimed in claim 9, wherein,

The elevator is provided with a load detection part for detecting the load in the elevator car,

The brake control unit switches the slip cancellation control system and the braking force control system based on the speed threshold value calculated based on information including the load of the car detected by the load detection unit.

12. The elevator according to any one of claims 1 to 4, wherein,

The brake control unit controls the braking force of the brake so that a state transition from a braking state to a releasing state of the brake does not occur in the slip cancellation control mode.

13. The elevator according to any one of claims 1 to 4, wherein,

The brake control unit controls the brake using, as the set deceleration, a deceleration having an absolute value smaller than a 1 st deceleration and having an absolute value larger than a 2 nd deceleration, the 1 st deceleration being calculated in advance as a deceleration at which the slip of the main rope with respect to the sheave does not occur, based on a predicted value of the traction capacity of the hoisting machine, and the 2 nd deceleration being calculated in advance as a deceleration at which a lower limit of the operation of a safety switch provided in the elevating path is not established.