Elevator brake control device

Abstract

There are concerns that the brake coil's return current could be damaged, potentially destroying the semiconductor switching elements that make up the switch. [Solution] An elevator brake control device that controls the contact and separation of brake shoes to brake drums by controlling the current flowing through the brake coil comprises: a first discharge circuit in which the anode side of a first diode and one end of a first resistor are connected at a first connection point, the cathode side of the first diode is connected to the positive side of the brake coil, and the other end of the first resistor is connected to the negative side of the brake coil; a second discharge circuit in which the cathode side of a second diode and one end of a second resistor are connected at a second connection point, the other end of the second resistor is connected to the positive side of the brake coil, and the anode side of the second diode is connected to the negative side of the brake coil via a switch; and a connection determination unit that determines the quality of the connections of the first resistor and the second resistor from the voltage values ​​of the first and second connection points, respectively.

Description

Technical Field

[0001] The present disclosure relates to an elevator brake control device.

Background Art

[0002] In an elevator brake control device, two brake shoes are brought into contact with a brake drum to brake the rotation of the brake drum. In Patent Document 1, a variable resistor and a switch are connected in parallel to a basic resistor. At the time of an emergency stop, the variable resistor and the basic resistor are connected in series to rapidly reduce the reflux current and rapidly bring the brake shoes into contact with the brake drum. At the time of a normal stop, the switch and the basic resistor are connected in series and the variable resistor is bypassed to gently reduce the reflux current and gently bring the brake shoes into contact with the brake drum.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the device of Patent Document 1, when there is an abnormality in the basic resistor, or when there is an abnormality in the contact between the basic resistor and the variable resistor or the switch, the reflux current cannot be processed. In this case, there is a concern that the energy accumulated in the brake coil loses a path to escape and destroys the semiconductor switching element constituting the switch.

[0005] An object of the present disclosure is to provide an elevator brake control device capable of detecting an abnormality in the connection of a resistor through which a reflux current flows.

Means for Solving the Problems

[0006] The elevator brake control device controls the contact and separation of the brake shoe to the brake drum by controlling the current flowing through the brake coil, and comprises: a first discharge circuit in which the anode side of a first diode and one end of a first resistor are connected at a first connection point, the cathode side of the first diode is connected to the positive side of the brake coil, and the other end of the first resistor is connected to the negative side of the brake coil; a second discharge circuit in which the cathode side of a second diode and one end of a second resistor are connected at a second connection point, the other end of the second resistor is connected to the positive side of the brake coil, and the anode side of the second diode is connected to the negative side of the brake coil via a switch; and a connection determination unit that determines the quality of the connections of the first resistor and the second resistor from the voltage values ​​of the first and second connection points, respectively. [Effects of the Invention]

[0007] This disclosure enables early detection of defects in resistors through which circulating current flows. This prevents the energy accumulated in the brake coil from having no escape route and damaging the semiconductor switching elements that make up the switch. [Brief explanation of the drawing]

[0008] [Figure 1] This is an overall configuration diagram of an elevator that utilizes the brake control device in Embodiment 1. [Figure 2] This is a circuit diagram showing the ON / OFF state of the brake control device switch and the flow of current in Embodiment 1. [Figure 3] This is a time chart showing the timing at which the connection check of the brake control device in Embodiment 1 is performed. [Figure 4] This diagram shows the changes in each switch of the brake control device, the current flowing through the first brake coil, and the torque applied to the first brake shoe in a time series in Embodiment 1. [Figure 5] This is a circuit diagram for comparison of brake control devices in Embodiment 1. [Modes for carrying out the invention]

[0009] The embodiments for implementing this disclosure will be described with reference to the attached drawings. In each drawing, the same or corresponding parts are denoted by the same reference numerals, and redundant explanations are simplified or omitted as appropriate.

[0010] Embodiment 1. Figure 1 is an overall configuration diagram of an elevator in which the brake control device in Embodiment 1 is used.

[0011] In Figure 1, the elevator 200 is equipped with a car 201 for passengers and a counterweight 202. The car 201 and the counterweight 202 are connected via a rope 203. The rope 203 is wound around a hoisting machine 204.

[0012] In such an elevator 200, when the hoisting machine 204 rotates, the rope 203 moves. This movement causes the car 201 and the counterweight 202 to move up and down in opposite directions.

[0013] The brake control device 10 consists of a brake device 11 and a brake control unit 100. The brake device 11 is equipped with a brake drum 12. The brake drum 12 is connected to the hoisting machine 204. The brake drum 12 rotates in accordance with the rotation of the hoisting machine 204. A first brake shoe 13a and a second brake shoe 13b are arranged on the outer surface of the outer circumferential surface of the brake drum 12. The first brake shoe 13a and the second brake shoe 13b are constantly biased in the direction of the brake drum 12 by springs or the like.

[0014] A first brake coil 14a is provided corresponding to the first brake shoe 13a. When current is supplied to the first brake coil 14a, it generates a magnetic force on the first brake shoe 13a in the opposite direction to the brake drum 12. As a result, the first brake shoe 13a is pulled away from the brake drum 12. A second brake coil 14b is provided corresponding to the second brake shoe 13b. When current is supplied to the second brake coil 14b, it generates a magnetic force on the second brake shoe 13b in the opposite direction to the brake drum 12. As a result, the second brake shoe 13b is pulled away from the brake drum 12.

[0015] The negative terminal side of the first brake coil 14a is connected to the first switch 15a and the second switch 16a, and is connected to ground. The positive terminal side of the first brake coil 14a is connected to the third switch 17a, and is connected to the first power supply 18a. The first switch 15a, the second switch 16a, and the third switch 17a are semiconductor switching elements such as IGBTs, MOSFETs, and transistors.

[0016] The first resistor 19a and the first diode 20a are connected in series between the first switch 15a and the negative terminal of the first brake coil 14a, and between the third switch 17a and the positive terminal of the first brake coil 14a. That is, the cathode side of the first diode 20a is connected between the third switch 17a and the positive terminal of the first brake coil 14a. The anode side of the first diode 20a is connected to one end of the first resistor 19a. The other end of the first resistor 19a is connected between the first switch 15a and the negative terminal of the first brake coil 14a. As a result, the first resistor 19a and the first diode 20a are connected in parallel with the first brake coil 14a.

[0017] A second diode 21a and a second resistor 22a are connected in series between the second switch 16a and the first switch 15a, and between the third switch 17a and the positive electrode side of the first brake coil 14a. That is, the anode side of the second diode 21a is connected between the second switch 16a and the first switch 15a. The cathode side of the second diode 21a is connected to one end of the second resistor 22a. The other end of the second resistor 22a is connected between the third switch 17a and the positive electrode side of the first brake coil 14a. Thereby, the second diode 21a and the second resistor 22a are in parallel with respect to the first brake coil 14a.

[0018] Note that there is a relationship of R1 > R2 between the resistance value R1 of the first resistor 19a and the resistance value R2 of the second resistor 22a.

[0019] A third diode 23a is connected between the second switch 16a and ground, and between the third switch 17a and the positive electrode side of the first brake coil 14a. That is, the anode side of the third diode 23a is connected between the second switch 16a and ground. The cathode side of the third diode 23a is connected between the third switch 17a and the positive electrode side of the first brake coil 14a. Thereby, the third diode 23a is in parallel with respect to the first brake coil 14a.

[0020] The first connection point 24a of the first resistor 19a and the first diode 20a is connected to ground via a third resistor 25a and a fourth resistor 26a.

[0021] The second connection point 27a of the second diode 21a and the second resistor 22a is connected to ground via a fifth resistor 28a and a sixth resistor 29a.

[0022] The brake control unit 100 includes a first switch control unit 101a, a second switch control unit 101b, a first connection determination unit 102a, and a second connection determination unit 102b.

[0023] The first switch control unit 101a transmits ON and OFF signals to the first switch 15a, the second switch 16a, and the third switch 17a as appropriate, controlling continuity and non-continuity.

[0024] The first connection determination unit 102a is connected to the third connection point 30a with the third resistor 25a and the fourth resistor 26a. It receives a signal based on the voltage value appearing at the third connection point 30a, in this case a cut signal 1, and determines the connection on the circuit. In this case, for example, a comparator (not shown) is used.

[0025] Furthermore, the first connection determination unit 102a is connected to the fourth connection point 31a with the fifth resistor 28a and the sixth resistor 29a. It then receives a signal based on the voltage value appearing at the fourth connection point 31a, in this case the cut signal 2, and determines the connection on the circuit.

[0026] Similarly, the negative terminal side of the second brake coil 14b is connected to the fourth switch 15b and the fifth switch 16b, and is connected to ground. The positive terminal side of the second brake coil 14b is connected to the sixth switch 17b, and is connected to the second power supply 18b. The fourth switch 15b, the fifth switch 16b, and the sixth switch 17b are semiconductor switching elements such as IGBTs, MOSFETs, and transistors.

[0027] The seventh resistor 19b and the fourth diode 20b are connected in series between the fourth switch 15b and the negative terminal of the second brake coil 14b, and between the sixth switch 17b and the positive terminal of the second brake coil 14b. That is, the cathode side of the fourth diode 20b is connected between the sixth switch 17b and the positive terminal of the second brake coil 14b. The anode side of the fourth diode 20b is connected to one end of the seventh resistor 19b. The other end of the seventh resistor 19b is connected between the fourth switch 15b and the negative terminal of the second brake coil 14b. As a result, the seventh resistor 19b and the fourth diode 20b are connected in parallel with the second brake coil 14b.

[0028] The fifth diode 21b and the eighth resistor 22b are connected in series between the fifth switch 16b and the fourth switch 15b, and between the sixth switch 17b and the positive terminal of the second brake coil 14b. That is, the anode side of the fifth diode 21b is connected between the fifth switch 16b and the fourth switch 15b. The cathode side of the fifth diode 21b is connected to one end of the eighth resistor 22b. The other end of the eighth resistor 22b is connected between the sixth switch 17b and the positive terminal of the second brake coil 14b. As a result, the fifth diode 21b and the eighth resistor 22b are connected in parallel with the second brake coil 14b.

[0029] Note that the resistance value of the seventh resistor 19b is the same as that of the first resistor 19a, R1. Also, the resistance value of the eighth resistor 22b is the same as that of the second resistor 22a, R2.

[0030] The sixth diode 23b connects the fifth switch 16b to ground and the sixth switch 17b to the positive terminal of the second brake coil 14b. That is, the anode of the sixth diode 23b is connected between the fifth switch 16b and ground. The cathode of the sixth diode 23b is connected between the sixth switch 17b and the positive terminal of the second brake coil 14b. As a result, the sixth diode 23b is connected in parallel with the second brake coil 14b.

[0031] The fifth connection point 24b between the seventh resistor 19b and the fourth diode 20b is connected to ground via the ninth resistor 25b and the tenth resistor 26b.

[0032] The sixth connection point 27b between the fifth diode 21b and the eighth resistor 22b is connected to ground via the eleventh resistor 28b and the twelfth resistor 29b.

[0033] The second switch control unit 101b transmits ON and OFF signals to the fourth switch 15b, the fifth switch 16b, and the sixth switch 17b as appropriate, controlling continuity and non-continuity.

[0034] The second connection determination unit 102b is connected to the seventh connection point 30b with the ninth resistor 25b and the tenth resistor 26b. It then receives a signal based on the voltage value appearing at the seventh connection point 30b, in this case a cut signal 1, and determines the contacts on the circuit.

[0035] Furthermore, the second connection determination unit 102b is connected to the eighth connection point 31b with the eleventh resistor 28b and the twelfth resistor 29b. It then receives a signal based on the voltage value appearing at the eighth connection point 31b, in this case the cut signal 2, and determines the contacts on the circuit.

[0036] Next, the operation of the brake control device 10 will be explained. Since the operation of the first brake coil 14a and the operation of the second brake coil 14b are basically the same, only the operation of the first brake coil 14a will be explained.

[0037] Figure 2 is a circuit diagram showing the ON / OFF state of the switch on the first brake coil 14a side and the flow of current. Note that the circuit on the first brake coil 14a side in Figure 1 has been partially simplified here, and the third resistor 25a, the fourth resistor 26a, the fifth resistor 28a, and the sixth resistor 29a have been omitted.

[0038] Figure 2(A) is a circuit diagram showing the operation during a connection check. During the connection check, the first switch 15a and the second switch 16a are turned off, and the third switch 17a is kept on at all times.

[0039] As a result, a voltage is applied from the first power supply 18a through the second resistor 22a and the second connection point 27a. Then, the voltage is detected at the fifth resistor 28a and the sixth resistor 29a, and a cut signal 2 is input to the first connection determination unit 102a. Also, a voltage is applied from the first power supply 18a through the first brake coil 14a, the first resistor 19a and the first connection point 24a. Then, the voltage is detected at the third resistor 25a and the fourth resistor 26a, and a cut signal 1 is input to the first connection determination unit 102a.

[0040] Naturally, if the first resistor 19a is faulty, the first connection determination unit 102a will not receive the cut signal 1. Similarly, if the second resistor 22a is faulty, the first connection determination unit 102a will not receive the cut signal 2. Therefore, the first connection determination unit 102a determines that the first resistor 19a is good if the cut signal 1 is input, and faulty if it is not. Likewise, it determines that the second resistor 22a is good if the cut signal 2 is input, and faulty if it is not.

[0041] Figure 3 is a time chart showing when connection checks are performed. The vertical axis shows the rotational speed of the hoisting machine 204. After departing the stopping floor, the hoisting machine 204 increases its rotational speed, then rotates at a constant speed, and as it approaches the target floor, it decreases its rotational speed and stops. Following the operation of the hoisting machine 204, the brake drum 12 also increases its rotational speed, rotates at a constant speed, descends, and stops.

[0042] The connection check is performed before the hoisting machine 204 starts rotating, that is, before the brake drum 12 starts rotating. It is also performed after the hoisting machine 204 stops rotating, that is, after the brake drum 12 stops rotating. The first connection determination unit 102a monitors the input of cut signal 1 and cut signal 2. If it determines that there is no input for either signal, it issues an alarm, indicating a malfunction. After this, the brake will not be released. Furthermore, the hoisting machine 204 will cease to operate after receiving this alarm. Note that the first connection determination unit 102a does not take any action even if cut signal 1 and cut signal 2 are detected or not detected at times other than during the connection check.

[0043] Figure 2(B) is a circuit diagram showing the operation when the brakes are released. When the brakes are released, the first switch 15a and the second switch 16a remain constantly on, while the third switch 17a repeatedly switches between on and off.

[0044] Current flows from the first power supply 18a to the first brake coil 14a, the first switch 15a, and the second switch 16a. As a result, the first brake coil 14a applies a magnetic force to the first brake shoe 13a in the opposite direction to that of the brake drum 12. This causes the first brake shoe 13a to be pulled away from the brake drum 12. In this state, the hoisting machine 204 rotates, causing the cage 201 to rise or fall. During this time, the third switch 17a repeatedly turns on and off to adjust the magnetic force applied to the first brake shoe 13a.

[0045] Figure 2(C) is a circuit diagram showing the operation during normal shutdown. During normal shutdown, the first switch 15a is always on, while the second switch 16a and the third switch 17a are off.

[0046] As a result, the circulating current flows through a second discharge circuit consisting of the negative side of the first brake coil 14a, the first switch 15a, the second diode 21a, the second resistor 22a, and the positive side of the first brake coil 14a, and eventually disappears. Figure 4 shows the changes in the current flowing through each switch and the first brake coil 14a and the torque applied to the first brake shoe 13a in time series. Figure 4(a) shows the time series during normal stopping.

[0047] Here, at time t1, the second switch 16a and the third switch 17a are turned off, and the current from the first power supply 18a is cut off. As a result, the current flowing through the first brake coil 14a decreases. At the same time, the magnetic force acting on the first brake shoe 13a weakens. Therefore, due to the biasing force, the first brake shoe 13a contacts and presses against the brake drum 12, increasing the torque. At time t2, the circulating current is discharged through the second resistor 22a, and the current flowing through the first brake coil 14a becomes zero.

[0048] Figure 2(D) is a circuit diagram showing the operation during an emergency stop. In the event of an emergency shutdown, the first switch 15a, the second switch 16a, and the third switch 17a are all turned off.

[0049] As a result, the circulating current flows through the first discharge circuit, which consists of the negative side of the first brake coil 14a, the first resistor 19a, the first diode 20a, and the positive side of the first brake coil 14a, and eventually disappears. Figure 4(b) shows the time series during an emergency stop.

[0050] Here, at time t1, the first switch 15a, the second switch 16a, and the third switch 17a are turned off, and the current from the first power supply 18a is cut off. As a result, at time t3, the current flowing through the first brake coil 14a becomes zero.

[0051] Note that the resistance value R1 of the first resistor 19a is greater than the resistance value R2 of the second resistor 22a. Therefore, the time interval between t3 and t1 during an emergency stop in Figure 4(b) is shorter than the time interval between t2 and t1 during a normal stop in Figure 4(a). The discharge time of the brake coil is generally determined by the return resistance. Therefore, if the discharge is to be short, it is necessary to connect a resistor with a larger resistance value. However, with a short discharge, the sound (dropping sound) when the brakes are applied will be louder. Therefore, in an emergency, the resistance value of the first resistor 19a is increased to prioritize discharge, even if it makes the sound louder. Note that the frequency of emergency stops is very low. Also, under normal circumstances, the resistance value of the second resistor 22a is kept low to avoid causing discomfort to passengers due to the operating sound.

[0052] Figure 5 is a circuit diagram in which the positions of the first resistor 19a and the first diode 20a are swapped for comparison with Figure 2(A). Specifically, the anode of the first diode 20a1 is connected between the first switch 15a and the negative terminal of the first brake coil 14a. The cathode of the first diode 20a1 is connected to one end of the first resistor 19a1. The other end of the first resistor 19a1 is connected between the third switch 17a and the positive terminal of the first brake coil 14a.

[0053] In this circuit configuration, during a connection check, a voltage is applied from the first power supply 18a through the first resistor 19a1 and the first connection point 24a. Additionally, a voltage is applied through the first brake coil 14a, the first diode 20a1, and the first connection point 24a. Therefore, even if the first resistor 19a1 is broken, it cannot be detected. Furthermore, during an emergency stop, an excessive voltage equal to the return current multiplied by the first resistor 19a1 is applied through the third resistor 25a and the fourth resistor 26a.

[0054] Taking these factors into consideration, the connections between the first diode 20a and the first resistor 19a were made in the order shown in Figure 1.

[0055] In Embodiment 1, a connection check allows for early detection of a faulty resistor through which circulating current flows. This prevents the energy accumulated in the brake coil from having no escape route and damaging the semiconductor switching elements that make up the switch.

[0056] Furthermore, by performing connection checks when the hoisting machine starts up and stops, the number of checks increases, allowing for more thorough and detailed responses.

[0057] Furthermore, the resistor that releases the return current during an emergency shutdown and the resistor that releases the return current during a normal shutdown are completely separate. Even if one resistor fails after a connection check, the other resistor may still be able to compensate.

[0058] By separating the resistance during emergency stops from that during normal stops, it became possible to perform braking operations according to the situation, prioritizing stopping time during emergency stops and sound during normal stops.

[0059] Although preferred embodiments have been described in detail above, the invention is not limited to these embodiments, and various modifications and substitutions can be made to the embodiments described above without departing from the scope of disclosure.

[0060] Furthermore, when referring to the number, quantity, amount, range, etc., of each element in the embodiments, the apparatus of this disclosure is not limited to the referred number unless specifically stated or clearly defined in principle. Also, the structures, etc., described in these embodiments are not necessarily essential unless specifically stated or clearly defined in principle. [Explanation of Symbols]

[0061] 10 Brake control device, 11 Brake device, 12 brake drums, 13a First brake shoe, 13b Second brake shoe, 14a First brake coil, 14b Second brake coil, 15a First switch, 15b Fourth switch, 16a Second switch, 16b Fifth switch, 17a Third switch, 17b Sixth switch, 18a First power supply, 18b Second power supply, 19a First resistor, 19b Seventh resistor, 20a First diode, 20b Fourth diode, 21a Second diode, 21b Fifth diode, 22a Second resistor, 22b Eighth resistor, 23a Third diode, 23b Sixth diode, 24a First connection point, 24b Fifth connection point, 25a Third resistor, 25b Ninth resistor, 26a The fourth resistor, 26b The tenth resistor, 27a Second connection point, 27b Sixth connection point, 28a fifth resistor, 28b eleventh resistor, 29a The 6th resistor, 29b The 12th resistor, 30a Third connection point, 30b Seventh connection point, 31a Fourth connection point, 31b Eighth connection point, 100 Brake control unit, 101a First switch control unit, 101b Second switch control unit, 102a First connection determination unit, 102b Second connection determination unit, 200 Elevator, 201 Car, 202 Weight, 203 Rope, 204 Hoisting machine

Claims

1. In an elevator brake control device that controls the contact and separation of the brake shoe from the brake drum by controlling the current flowing through the brake coil, A first discharge circuit is formed in which the anode side of the first diode and one end of the first resistor are connected at a first connection point, the cathode side of the first diode is connected to the positive side of the brake coil, and the other end of the first resistor is connected to the negative side of the brake coil. A second discharge circuit is provided, in which the cathode side of the second diode and one end of the second resistor are connected at a second connection point, the other end of the second resistor is connected to the positive side of the brake coil, and the anode side of the second diode is connected to the negative side of the brake coil via a switch. An elevator brake control device comprising: a connection determination unit that determines whether the connection of the first resistor and the second resistor is good or bad based on the voltage values ​​of the first connection point and the second connection point, respectively.

2. The elevator brake control device according to claim 1, characterized in that the resistance value of the first resistor is greater than the resistance value of the second resistor.

3. The elevator brake control device according to claim 1 or 2, characterized in that the connection determination unit performs the determination before the brake drum rotates.

4. The elevator brake control device according to claim 1 or 2, characterized in that the connection determination unit performs the determination after the brake shoe has come into contact with the brake drum and the rotation of the brake drum has stopped.

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