Brake control systems for industrial vehicles

Abstract

To provide a brake control device of an industrial vehicle which enables electric power supply to a brake part during operation of a shut-off switch and can inhibit rapid brake caused when electric power supply to the brake part is stopped.SOLUTION: A brake control device 100 includes: a contactor 5 provided between a battery 4 and an inverter 8, including a main contact 5a and a coil 5d, and configured to switch its state between a conduction state and a cut-off state by the coil 5d driving the main contact 5a according to electric power supply from the battery 4; a cut-off switch 6 which cuts off the electric power supply from the battery 4 to the coil 5d so as to switch the contactor 5 into the cut-off state; and a self power generation type electromagnetic retarder 13 which enables regeneration by rotation of a motor 2. In the conduction state of the contactor 5, electric power is supplied from a circuit portion 9 between the contactor 5 and the inverter 8 or the electromagnetic retarder 13 to an electromagnetic brake 3. In the cut-off state of the contactor 5, electric power is supplied from the electromagnetic retarder 13.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a braking control device for an industrial vehicle.

Background Art

[0002] Conventionally, a non-energized operation type electromagnetic brake that brakes a rotating shaft when not energized and releases the braking of the rotating shaft when energized is known (for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] For example, when a non-energized operation type electromagnetic brake is used as a parking brake of an industrial vehicle, if the power supply to the electromagnetic brake is composed only of a power source such as a battery, when an emergency stop switch for stopping the running industrial vehicle is operated, the power supply to the braking unit will be interrupted. As a result, countermeasures against the sudden braking caused by the operation of the braking unit have been studied.

[0005] An object of the present invention is to provide a braking control device for an industrial vehicle that enables power supply to the braking unit when the cutoff switch is operated and can suppress sudden braking caused by interruption of power supply to the braking unit.

Means for Solving the Problems

[0006] One aspect of the present invention is a braking control device for an industrial vehicle that controls the braking unit of an industrial vehicle comprising a motor for driving, a braking unit that releases the braking of the motor by supplying power, a power supply unit that supplies power to the motor, and an inverter that provides mutual power supply between the motor and the power supply unit, comprising: a switch unit provided between the power supply unit and the inverter, including a main contact and a coil that drives the main contact, wherein the coil drives the main contact to switch between a conductive state and an interrupted state in response to power supply from the power supply unit; an interruption switch capable of interrupting the power supply from the power supply unit to the coil to switch the switch unit to an interrupted state; and a self-generating electromagnetic retarder that can regenerate power through the rotation of the motor, wherein the braking unit is supplied with power from the circuit portion between the switch unit and the inverter or the electromagnetic retarder when the switch unit is conductive, and is supplied with power from the electromagnetic retarder when the switch unit is interrupted.

[0007] In a braking control device for an industrial vehicle according to one aspect of the present invention, when the cutoff switch is operated and the power supply from the power supply unit to the coil is cut off, the switch unit enters a cutoff state. At this time, the braking unit is no longer supplied with power from the circuit between the switch unit and the inverter, but it can be supplied with power from the electromagnetic retarder. Therefore, power can be supplied to the braking unit when the cutoff switch is operated, and sudden braking caused by the interruption of power supply to the braking unit can be suppressed.

[0008] In one embodiment, the braking control device for an industrial vehicle includes a detection unit that detects the power supply from the power supply unit to the coil, and a control unit that controls an electromagnetic retarder based on the detection result of the detection unit. The control unit is supplied with power from the circuit between the switch unit and the inverter or from the electromagnetic retarder when the switch unit is conductive, and from the electromagnetic retarder when the switch unit is disconnected. The control unit may control the electromagnetic retarder to regenerate power when it detects that the power supply from the power supply unit to the coil has been interrupted. In this case, when the power supply from the power supply unit to the coil has been interrupted based on the detection result of the detection unit, the control unit controls the electromagnetic retarder to regenerate power. In this way, power can be supplied to the braking unit when the disconnection switch is operated using a control unit that controls the electromagnetic retarder.

[0009] In one embodiment, the industrial vehicle is configured such that the driving force generated by the motor is transmitted to the drive wheels via the drive system, and the electromagnetic retarder may be provided on the opposite side of the motor from the drive system. In this case, the electromagnetic retarder can be provided while maintaining the configuration between the motor and the drive system. [Effects of the Invention]

[0010] According to one aspect of the present invention, power can be supplied to the braking unit when the cutoff switch is operated, and sudden braking caused by the interruption of power supply to the braking unit can be suppressed. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram illustrating an industrial vehicle equipped with a braking control device according to one embodiment of the industrial vehicle. [Figure 2] This is a schematic block diagram illustrating a circuit configuration when the switch unit is in a conductive state in a braking control device for an industrial vehicle according to one embodiment. [Figure 3] This is a schematic block diagram illustrating a circuit configuration when the switch unit is in the off state in a braking control device for an industrial vehicle according to one embodiment. [Figure 4] This is a flowchart showing an example of controller processing. [Modes for carrying out the invention]

[0012] Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same or equivalent elements will be denoted by the same reference numerals, and redundant descriptions will be omitted.

[0013] Figure 1 is a schematic diagram illustrating an industrial vehicle equipped with an industrial vehicle brake control device according to one embodiment. Figure 2 is a schematic block diagram illustrating a circuit configuration when the switch unit is in a conductive state in the industrial vehicle brake control device according to one embodiment. The industrial vehicle brake control device 100 according to this embodiment is a control device that controls the electromagnetic brake (braking unit) 3 of the industrial vehicle 1. An example of an industrial vehicle 1 on which the industrial vehicle brake control device 100 is mounted is an electric forklift.

[0014] As shown in Figures 1 and 2, the industrial vehicle 1, as an example, includes front wheels 1a, rear wheels 1b, a motor 2, an electromagnetic brake 3, a battery (power supply unit) 4, a contactor (switch unit) 5, a cutoff switch 6, a current sensor (detection unit) 7, an inverter 8, a circuit unit 9, a controller (control unit) 10, a drive system 12, and an electromagnetic retarder 13. The industrial vehicle 1 is configured such that the driving force generated by the motor 2 is transmitted to the drive wheels via the drive system 12. The contactor 5, cutoff switch 6, current sensor 7, controller 10, and electromagnetic retarder 13 constitute the braking control device 100 of the industrial vehicle.

[0015] The front wheels 1a are wheels located at the front of the body of the industrial vehicle 1 and are drive wheels driven by the motor 2. If the industrial vehicle 1 is an electric forklift, the front wheels 1a correspond to the wheels on the side of the industrial vehicle 1 where the load handling equipment, including the mast and forks, is installed. The rear wheels 1b are wheels located at the rear of the body of the industrial vehicle 1 and are non-drive wheels not driven by the motor 2. The front wheels 1a and rear wheels 1b consist of, for example, a pair of left and right wheels.

[0016] The motor 2 is a motor generator for driving the industrial vehicle 1. The motor 2 is, for example, a three-phase AC rotating electric motor. The motor 2 generates a driving force in response to the power supply from the battery 4.

[0017] A vehicle speed sensor 2a is provided in the motor 2. The vehicle speed sensor 2a is a sensor that directly or indirectly obtains the rotational speed of the front wheel 1a as the vehicle speed of the industrial vehicle 1. The vehicle speed sensor 2a can be a motor rotational speed sensor that obtains the rotational speed of the motor 2. The vehicle speed sensor 2a transmits a signal regarding the obtained rotational speed of the motor 2 to the controller 10.

[0018] A drive system 12 is interposed between the front wheel 1a and the motor 2. The drive system 12 forms a power transmission path between the front wheel 1a and the motor 2 in the industrial vehicle 1. The drive system 12 has, for example, a speed reducer 12a incorporating a gear and a shaft for speed reduction. The motor 2 is attached to the speed reducer 12a. The front wheel 1a is driven by the motor 2 via the drive system 12.

[0019] The electromagnetic brake 3 is, for example, a braking device used as a parking brake when the industrial vehicle 1 is parked. The electromagnetic brake 3 is a non-excitation operation type electromagnetic brake configured to be able to brake the motor ۲. The electromagnetic brake 3 releases the braking of the motor 2 by power supply. When the power supply to the electromagnetic brake 3 stops, the electromagnetic brake 3 brakes the motor 2. Therefore, for example, when the power supply to the electromagnetic brake 3 stops during the running of the industrial vehicle 1, the industrial vehicle 1 can be suddenly braked.

[0020] The electromagnetic brake 3 is provided on the motor 2 side with reference to the drive system 12. The electromagnetic brake 3 can brake the motor 2 without passing through the drive system 12. The electromagnetic brake 3 here is provided on the opposite side of the drive system 12 of the motor 2. The electromagnetic brake 3 is fixed to the end face on the opposite side of the drive system 12 of the motor 2 so as to brake the shaft of the motor 2 protruding from the end on the opposite side of the drive system 12 of the motor 2, for example.

[0021] The electromagnetic retarder 13 is a self - generating type electromagnetic retarder. The self - generating type means that the electromagnetic retarder 13 can generate regenerative power by the rotation of the shaft to be braked (here, the rotation of the motor 2). The electromagnetic retarder 13 can supply the regenerative power to the outside. The electromagnetic retarder 13 here includes an AC / DC converter, which converts the regenerative power, which is AC power, into DC power and supplies the DC power to the outside.

[0022] The electromagnetic retarder 13 can use a known configuration. For example, when an operation signal from the controller 10 is input, an internal switching element is turned on, and a resonance circuit of an electromagnetic coil and a capacitor arranged in a stator that does not rotate with the shaft of the motor 2 is formed. Eddy currents are generated in a metal rotating member that rotates with the shaft of the motor 2, and braking force is generated by the eddy currents generating Joule heat. Also, a three - phase AC voltage is generated in the resonance circuit, and the electromagnetic retarder 13 can output regenerative power by controlling the opening and closing of the internal switching element.

[0023] The electromagnetic retarder 13 is provided on the motor 2 side with respect to the drive system 12. The electromagnetic retarder 13 can brake the motor 2 without passing through the drive system 12. The electromagnetic retarder 13 here is provided on the side opposite to the drive system 12 of the motor 2. For example, a metal rotating member is fixed to the shaft of the motor 2 that protrudes from the end on the side opposite to the drive system 12 of the electromagnetic brake 3, and a stator is fixed to the end face on the side opposite to the drive system 12 of the electromagnetic brake 3.

[0024] An operation signal may be input from the controller 10 so that the internal switching element is turned on when a metal rotating member fixed to the shaft of the motor 2 rotates at a predetermined rotational speed threshold or higher. The rotational speed threshold is the threshold of the rotational speed of the rotation of the shaft to be braked (here, the rotation of the motor 2) at which the electromagnetic brake 3 and the controller 10 can operate and output regenerative power.

[0025] Battery 4 is a power source that outputs DC power. For example, a secondary battery such as a lead-acid battery or a lithium-ion battery can be used as Battery 4. Battery 4 supplies power to the motor 2. The positive electrode 4a of Battery 4 is connected to one end 5b of the main contact 5a of the contactor 5 and to one end 6a of the cutoff switch 6.

[0026] The contactor 5 is a switch located between the battery 4 and the inverter 8. The contactor 5 switches the electrical connection and disconnection of the battery 4 as the main power source in response to the operation of, for example, the main switch (e.g., key switch) of the industrial vehicle 1. The contactor 5 is composed of a main contact 5a and a coil 5d that drives the main contact 5a. The contactor 5 switches between a conductive state and a disconnected state in response to the power supply from the battery 4 to the coil 5d. The conductive state is when the main contact 5a is closed, and the battery 4 and the inverter 8 are electrically connected. The disconnected state is when the main contact 5a is open, and the battery 4 and the inverter 8 are electrically disconnected.

[0027] The main contact 5a is a movable contact for switching the electrical connection and disconnection of the battery 4, which serves as the main power source. One end 5b of the main contact 5a is connected to the positive terminal 4a of the battery 4. The other end 5c of the main contact 5a is connected to the first end 9a of the circuit section 9 between the contactor 5 and the inverter 8.

[0028] The circuit section 9 is part of the circuit that constitutes the braking control device 100 of the industrial vehicle, and connects the contactor 5, the inverter 8, and the controller 10. In the example shown in Figure 2, the circuit section 9 has a wire 9c extending from the first end 9a to the second end 9b, and a wire 9e branching off from the wire 9c and extending to the third end 9d.

[0029] The coil 5d is energized or demagnetized in response to power supply from the battery 4, and drives the main contact 5a of the contactor 5 to open and close. One end 5e of the coil 5d is connected to the other end 6b of the trip switch 6. A portion of the coil between the end 5e of the coil 5d and the other end 6b of the trip switch 6 may pass through the inside of the controller 10. The other end 5f of the coil 5d is connected to the negative electrode 4b side of the battery 4 (for example, the vehicle body ground of the industrial vehicle 1). A portion of the coil between the other end 5f of the coil 5d and the negative electrode 4b side of the battery 4 may pass through the inside of the controller 10.

[0030] The disconnect switch 6 is operated to stop the industrial vehicle 1 in an emergency while it is in motion. The disconnect switch 6 is, for example, an emergency stop button. The disconnect switch 6 is installed, for example, in the driver's seat of the industrial vehicle 1 in a position where it can be operated by the driver. The disconnect switch 6 is located between the battery 4 and one end 5e of the coil 5d. When not operated, the disconnect switch 6 electrically connects the battery 4 and the coil 5d. When operated, the disconnect switch 6 electrically disconnects the battery 4 and the coil 5d. That is, when the disconnect switch 6 is operated, it is possible to cut off the power supply from the battery 4 to the coil 5d so as to switch the contactor 5 to the disconnected state.

[0031] With the configuration described above, in the contactor 5, when the cutoff switch 6 is not operated, power is supplied to the coil 5d from the battery 4, so the coil 5d drives the main contact 5a to close. Therefore, when the cutoff switch 6 is not operated, the contactor 5 is in a conductive state, electrically connecting the battery 4 and the inverter 8. On the other hand, when the cutoff switch 6 is operated, the power from the battery 4 to the coil 5d is cut off, so the main contact 5a, which is no longer driven by the coil 5d, opens. Therefore, when the cutoff switch 6 is operated, the contactor 5 is in a cutoff state, electrically disconnecting the battery 4 and the inverter 8.

[0032] A current sensor 7 may be provided between one end 5e of the coil 5d and the other end 6b of the cutoff switch 6. The current sensor 7 is a detection unit that detects the power supply from the battery 4 to the coil 5d. The current sensor 7 is provided, for example, in the part that passes inside the controller 10 between one end 5e of the coil 5d and the other end 6b of the cutoff switch 6. The current sensor 7 detects the current flowing from the battery 4 to the coil 5d and transmits the detected current information to the controller 10.

[0033] The inverter 8 converts and supplies power between the motor 2 and the battery 4. The inverter 8 converts DC power from the battery 4 into AC power to supply to the motor 2. The inverter 8 is a known three-phase inverter, for example, comprising IGBTs. The DC positive terminal 8a of the inverter 8 is connected to the second terminal 9b of the wiring 9c of the circuit section 9. The DC negative terminal 8b of the inverter 8 is connected to the negative terminal 4b side of the battery 4 (for example, the vehicle body ground). The AC terminal 8c of the inverter 8 is connected to the motor 2. The dashed lines L1 to L11 in Figures 2 and 3 indicate the flow of current, with the current flowing towards the tip of the arrow. As shown by the dashed line L1 in Figure 2, the inverter 8 is supplied with DC power from the battery 4 via the contactor 5 when the cutoff switch 6 is not operated. As shown by the dashed line L2 in Figure 2, the inverter 8 converts the supplied DC power into AC power and outputs it to the motor 2. In this case, the path from motor 2 to battery 4 is the path shown by dashed lines L3 to L5 in Figure 2, forming a closed circuit.

[0034] A DC / DC converter may be interposed between the contactor 5 and the inverter 8 (for example, on wiring 9c). The DC / DC converter, for example, boosts the voltage of the DC power from the battery 4 to the inverter 8. In this case, the inverter 8 converts the DC power from the DC / DC converter into AC power.

[0035] Controller 10 is an electronic control unit that controls the electromagnetic brake 3 of the industrial vehicle 1. Controller 10 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), CAN (Controller Area Network) communication circuit, etc. Controller 10 implements various functions, for example, by loading a program stored in ROM into RAM and executing the program loaded into RAM with the CPU. Controller 10 may be composed of multiple electronic control units.

[0036] The positive terminal 10a of the power terminal of the controller 10 is connected to the third terminal 9d of the wiring 9e of the circuit section 9. The negative terminal 10b of the power terminal of the controller 10 is connected to the negative terminal 4b side of the battery 4 (for example, the vehicle body ground). The controller 10 operates when power is supplied to the positive terminal 10a from the wiring 9e of the circuit section 9, as shown by the dashed line L6 in Figure 2. The positive terminal 10c of the output terminal of the controller 10 is connected to the positive terminal 3a of the electromagnetic brake 3. The negative terminal 10d of the output terminal of the controller 10 is connected to the negative terminal 3b of the electromagnetic brake 3. As shown by the dashed lines L7 and L8 in Figure 2, the controller 10 can supply a portion of the power supplied to the positive terminal 10a to the electromagnetic brake 3. That is, the electromagnetic brake 3 and the controller 10 are supplied with power from the circuit section 9 between the contactor 5 and the inverter 8 when the contactor 5 is in a conductive state.

[0037] Figure 3 is a schematic block diagram illustrating a circuit configuration in an industrial vehicle braking control device according to one embodiment, when the switch unit is in the off state. Figure 3 illustrates a circuit configuration where the off switch 6 is operated and the contactor 5 is switched to the off state.

[0038] The controller 10 detects the interruption of power supply from the battery 4 to the coil 5d based on the detection result of the current sensor 7. For example, the controller 10 detects the interruption of power supply from the battery 4 to the coil 5d when it detects that the current has stopped flowing from the battery 4 to the coil 5d due to the operation of the cutoff switch 6, based on the current information detected by the current sensor 7. For example, the controller 10 detects the interruption of power supply from the battery 4 to the coil 5d when the current value from the battery 4 to the coil 5d falls below a predetermined cutoff threshold. The cutoff threshold may be, for example, 0A, or a current value slightly greater than 0A.

[0039] When the controller 10 detects that the power supply from the battery 4 to the coil 5d has been interrupted, it controls the electromagnetic retarder 13 to regenerate power. When the controller 10 detects that the power supply from the battery 4 to the coil 5d has been interrupted due to the operation of the interruption switch 6, it may also control the electromagnetic retarder 13 so that the regenerative power of the electromagnetic retarder 13 is equal to or greater than a predetermined interruption regenerative power. The interruption regenerative power is the regenerative power generated by the electromagnetic retarder 13 when the interruption switch 6 is operated. The interruption regenerative power can be set to be a power that is larger than the power required to operate the controller 10 and the electromagnetic brake 3 by a predetermined margin. The predetermined margin is a power margin that is sufficient so that the operation of the controller 10 and the electromagnetic brake 3 does not stop midway, even if fluctuations in regenerative power occur, for example.

[0040] When the controller 10 detects a power interruption from the battery 4 to the coil 5d, it may send an activation signal to the electromagnetic retarder 13 so that an internal switching element is turned ON when the metal rotating member fixed to the shaft of the motor 2 is rotating at a predetermined rotational speed threshold or higher. This ensures that the regenerative power of the electromagnetic retarder 13 is equal to or higher than the predetermined regenerative power at the time of power interruption.

[0041] Incidentally, when the cutoff switch 6 is operated, there is a short period of time before the main contact 5a opens and the contactor 5 enters the cutoff state. During this short period, power is continuously supplied from the battery 4 to the electromagnetic brake 3 and the controller 10. Therefore, during this short period, the controller 10 sends an operation signal to control the electromagnetic retarder 13 to perform regenerative braking. More precisely, the communication cycle of the CAN communication circuit between the controller 10 and the electromagnetic retarder 13 may also be considered. For example, when the controller 10 detects a cutoff in the power supply from the battery 4 to the coil 5d, it may send an operation signal to control the electromagnetic retarder 13 to perform regenerative braking asynchronously with respect to the communication cycle of the CAN communication circuit (without waiting until the next communication cycle). When the controller 10 detects a cutoff in the power supply from the battery 4 to the coil 5d, it may change the communication cycle to a shorter one than when the power supply cutoff is not detected and send an operation signal to control the electromagnetic retarder 13 to perform regenerative braking. Alternatively, by increasing the size of the energy storage element, such as a capacitor, included in the controller 10, it may be possible to transmit an operating signal to the electromagnetic retarder 13 for a predetermined time after the contactor 5 has been shut off.

[0042] When the electromagnetic retarder 13 detects a disruption in the power supply from the battery 4 to the coil 5d, it regenerates power in response to an activation signal from the controller 10, and the regenerated power from the electromagnetic retarder 13 is converted into DC power by an AC / DC converter. The regenerated power converted into DC power by the AC / DC converter is supplied from the electromagnetic retarder 13 to the electromagnetic brake 3 and the controller 10, as shown by the dashed lines L9 to L11 in Figure 3.

[0043] Specifically, the positive terminal 13a of the output terminal of the electromagnetic retarder 13 is connected to the positive terminal 10e of the controller 10. The controller 10 operates by power being supplied from the positive terminal 13a of the electromagnetic retarder 13 to the positive terminal 10e of the controller 10, as shown by the dashed line L9 in Figure 3. The negative terminal 10f of the controller 10 is connected to the positive terminal 3a of the electromagnetic brake 3. The controller 10 can supply a portion of the power supplied to the positive terminal 10e to the electromagnetic brake 3. The electromagnetic brake 3 operates by power being supplied from the negative terminal 10f of the controller 10 to the positive terminal 3a of the electromagnetic brake 3, as shown by the dashed line L10 in Figure 3. In other words, the electromagnetic brake 3 and the controller 10 are powered by the electromagnetic retarder 13 when the contactor 5 is disconnected.

[0044] The negative terminal 3b of the electromagnetic brake 3 is connected to the negative terminal 13b of the output terminal of the electromagnetic retarder 13. The DC power returning from the electromagnetic brake 3 returns from the negative terminal 3b of the electromagnetic brake 3 to the negative terminal 13b of the electromagnetic retarder 13, as shown by the dashed line L11 in Figure 3. In this way, when the trip switch 6 is operated, a closed circuit is formed in which the electromagnetic retarder 13, controller 10, and electromagnetic brake 3 are connected in series, as shown by the dashed lines L9 to L11 in Figure 3.

[0045] Figure 4 is a flowchart illustrating an example of controller processing. The processing shown in the flowchart in Figure 4 is repeatedly executed at predetermined calculation cycles, for example, while the industrial vehicle 1 is in motion.

[0046] In S10, the controller 10 of the industrial vehicle's braking control device 100 acquires the detection result of the current sensor 7, which is the detection unit. For example, the controller 10 acquires current information of the current flowing from the battery 4 to the coil 5d, as detected by the current sensor 7.

[0047] In S11, the controller 10 acquires the rotational speed of the motor 2. The controller 10 acquires the rotational speed of the motor 2 detected by, for example, the vehicle speed sensor 2a. In this case, the controller 10 acquires the rotational speed of the motor 2 in place of the vehicle speed of the industrial vehicle 1.

[0048] In S12, the controller 10 determines whether or not it has detected a disruption in the power supply from the battery 4 to the coil 5d. For example, if the controller 10 detects that the current has stopped flowing from the battery 4 to the coil 5d due to the operation of the cutoff switch 6, it detects a disruption in the power supply from the battery 4 to the coil 5d.

[0049] If the controller 10 does not detect a disruption in the power supply from the battery 4 to the coil 5d (S12: NO), the controller 10 controls the electromagnetic retarder 13 in S13 to prevent regeneration. For example, the controller 10 does not send an operating signal to the electromagnetic retarder 13 to turn on the switching element inside the electromagnetic retarder 13. After that, the controller 10 terminates the process shown in Figure 4.

[0050] On the other hand, if the controller 10 detects that the power supply from the battery 4 to the coil 5d has been interrupted (S12: YES), the controller 10 determines in S14 whether the rotational speed of the motor 2 is above a rotational speed threshold.

[0051] If the controller determines that the rotational speed of motor 2 is not above the rotational speed threshold (i.e., below the rotational speed threshold) (S14: NO), the controller 10 proceeds to the process in S13. After that, the controller 10 terminates the process shown in Figure 4.

[0052] On the other hand, if the controller determines that the rotational speed of motor 2 is equal to or greater than the rotational speed threshold (S14: YES), the controller 10 controls the electromagnetic retarder 13 in S15 to regenerate power. The controller 10 regenerates power by, for example, sending an operating signal to the electromagnetic retarder 13 to turn on the switching element inside the electromagnetic retarder 13. After that, the controller 10 terminates the process shown in Figure 4.

[0053] With the braking control device 100 for industrial vehicles configured as described above, when the cutoff switch 6 is operated and the power supply from the battery 4 to the coil 5d is cut off, the contactor 5 enters a cutoff state. At this time, the electromagnetic brake 3 is no longer supplied with power from the circuit section 9 between the contactor 5 and the inverter 8, but it can still be supplied with power from the electromagnetic retarder 13. Therefore, power can be supplied to the electromagnetic brake 3 when the cutoff switch 6 is operated, and sudden braking caused by the interruption of power supply to the electromagnetic brake 3 can be suppressed.

[0054] The braking control device 100 for industrial vehicles includes a current sensor 7 that detects the power supply from the battery 4 to the coil 5d, and a controller 10 that controls the electromagnetic retarder 13 based on the detection result of the current sensor 7. The controller 10 is supplied with power from the circuit section 9 between the contactor 5 and the inverter 8 or from the electromagnetic retarder 13 when the contactor 5 is conducting. The controller 10 is supplied with power from the electromagnetic retarder 13 when the contactor 5 is disconnected. When the controller 10 detects that the power supply from the battery 4 to the coil 5d has been interrupted, it controls the electromagnetic retarder 13 to regenerate power. Thus, when the power supply from the battery 4 to the coil 5d has been interrupted based on the detection result of the current sensor 7, the controller 10 controls the electromagnetic retarder 13 to regenerate power. In this way, power can be supplied to the electromagnetic brake 3 when the cutoff switch 6 is operated using the controller 10 that controls the electromagnetic retarder 13.

[0055] In the braking control device 100 for industrial vehicles, the industrial vehicle 1 is configured to transmit the driving force generated by the motor 2 to the front wheels 1a via the drive system 12. The electromagnetic retarder 13 is located on the opposite side of the motor 2 from the drive system 12. This allows the electromagnetic retarder 13 to be installed while maintaining the configuration between the motor 2 and the drive system 12.

[0056] [Differentiation] The present invention is not limited to the embodiments described above. The present invention can be implemented in various forms, including the embodiments described above, with various modifications and improvements based on the knowledge of those skilled in the art.

[0057] In the above embodiment, a battery 4, which is a secondary battery such as a lead-acid battery or lithium-ion battery, was shown as an example of a power supply unit, but the invention is not limited to this example. The power supply unit may be, for example, an electric double-layer capacitor. The power supply unit may include a fuel cell. The power supply unit may be a combination of an external power supply and a storage battery. The external power supply may be a DC power supply, or an AC power supply may be used by interposing an AC / DC converter.

[0058] In the above embodiment, an electromagnetic brake 3 was shown as an example of a braking unit, but the system is not limited to this example. In short, any braking device other than the electromagnetic brake 3 may be used, as long as it can release the braking of the motor 2 by supplying power and brake the motor 2 when the power supply is cut off.

[0059] In the above embodiment, a current sensor 7 was shown as an example of a detection unit for detecting power supply from the battery 4 to the coil 5d, but the invention is not limited to this example. For example, the detection unit may be a voltage sensor that detects the potential difference between the positive electrode 4a of the battery 4 and one end 5e of the coil 5d. Furthermore, the detection unit does not necessarily have to be provided in a portion that passes inside the controller 10 between one end 5e of the coil 5d and the other end 6b of the cutoff switch 6, as is the case with the current sensor 7.

[0060] In the above embodiment, a contactor 5 (electromagnetic contactor) was shown as an example of the switch section, but the invention is not limited to this example. For example, an electromagnetic switch (magnetic switch) may be used, which combines a thermal relay with the contactor 5.

[0061] In the above embodiment, the electromagnetic brake 3 and electromagnetic retarder 13 were provided on the side of the motor 2 opposite the drive system 12, in the order of electromagnetic brake 3 followed by electromagnetic retarder 13 as viewed from the motor 2, but the system is not limited to this example. They may be provided in the order of electromagnetic retarder 13 followed by electromagnetic brake 3 as viewed from the motor 2. Also, although the electromagnetic brake 3 and electromagnetic retarder 13 were provided on the side of the motor 2 opposite the drive system 12, the system is not limited to this example. At least one of the electromagnetic brake 3 and electromagnetic retarder 13 may be provided between the motor 2 and the drive system 12, or on the drive system 12, or between the drive system 12 and the front wheel 1a.

[0062] In the above embodiment, the electromagnetic retarder 13 was controlled to regenerate power using the current sensor 7 and the controller 10, but the current sensor 7 and the controller 10 are not essential. For example, the configuration may be such that the regenerative power regenerated by the electromagnetic retarder 13 is always supplied to the electromagnetic brake 3.

[0063] In the above embodiment, the electromagnetic brake 3 and controller 10 were supplied with power from the circuit portion 9 between the contactor 5 and the inverter 8 when the contactor 5 was conducting. However, the regenerative power generated by the electromagnetic retarder 13 may also be used when the contactor 5 is conducting. In this case, if the controller 10 does not detect a cutoff in the power supply from the battery 4 to the coil 5d (S12:NO), and the rotational speed of the motor 2 is above the rotational speed threshold, the electromagnetic brake 3 and controller 10 may be supplied with power using the regenerative power of the electromagnetic retarder 13. Note that if the controller 10 does not detect a cutoff in the power supply from the battery 4 to the coil 5d (S12:NO), and the rotational speed of the motor 2 is not above the rotational speed threshold (below the rotational speed threshold), the regenerative power may be insufficient, so the electromagnetic brake 3 and controller 10 may be supplied with power from the circuit portion 9 between the contactor 5 and the inverter 8.

[0064] In the above embodiment, the controller 10 made a determination in S14 whether the rotational speed of the motor 2 was equal to or greater than the rotational speed threshold, but the determination in S14 may be omitted. In this case, for example, the controller 10 may control the electromagnetic retarder 13 in S15 to regenerate power into the electromagnetic retarder 13, so that the regenerative power of the electromagnetic retarder 13 can be left to chance.

[0065] Furthermore, the electromagnetic retarder 13 may be configured to change the strength of regenerative braking in response to an operating signal from the controller 10 when the rotational speed of the shaft being braked is constant. In this case, the controller 10 may transmit an operating signal to the electromagnetic retarder 13 so that the regenerative power of the electromagnetic retarder 13 is equal to or greater than a predetermined regenerative power at the time of interruption.

[0066] In the above embodiment, the controller 10 that controls the inverter 8 and the like controls the electromagnetic retarder 13, but a separate controller for the electromagnetic retarder 13 may also be provided.

[0067] In the above embodiment, an electric forklift was shown as the industrial vehicle 1 on which the industrial vehicle braking control device 100 is mounted, but the invention is not limited to this example. For example, the industrial vehicle may be other industrial vehicles such as towing vehicles or transport vehicles. The industrial vehicle may include a motor powered by a power supply unit and a braking unit that can release the motor's braking by supplying power, and may also be configured to use an engine in conjunction with the industrial vehicle. [Explanation of symbols]

[0068] 1...Industrial vehicle, 2...Motor, 3...Electromagnetic brake (braking unit), 4...Battery (power supply unit), 5...Contactor (switch unit), 5a...Main contact, 5d...Coil, 6...Cut-off switch, 7...Current sensor (detection unit), 8...Inverter, 9...Circuit section, 10...Controller (control unit), 12...Drive system, 13...Electromagnetic retarder, 100...Brake control device for industrial vehicles.

Claims

1. A braking control device for an industrial vehicle, comprising a motor for driving, a braking unit that releases the brake of the motor by supplying power, a power supply unit that supplies power to the motor, and an inverter that provides mutual power supply between the motor and the power supply unit, wherein the braking unit of the industrial vehicle is controlled, A switch unit is provided between the power supply unit and the inverter, and includes a main contact and a coil for driving the main contact, wherein the coil drives the main contact in response to power supply from the power supply unit to switch between a conductive state and a disconnected state. A cutoff switch capable of cutting off the power supply from the power supply unit to the coil so as to switch the switch unit to the cutoff state, It comprises a self-generating electromagnetic retarder that can regenerate power through the rotation of the motor, The braking unit includes, When the switch section is in a conductive state, power is supplied from the circuit section between the switch section and the inverter or from the electromagnetic retarder. A braking control device for an industrial vehicle, which is powered by the electromagnetic retarder when the switch section is in an interrupted state.

2. A detection unit for detecting the power supply from the power supply unit to the coil, The system includes a control unit that controls the electromagnetic retarder based on the detection result of the detection unit, The control unit includes: When the switch section is in a conductive state, power is supplied from the circuit section between the switch section and the inverter or from the electromagnetic retarder. When the switch section is in the disconnected state, power is supplied from the electromagnetic retarder. The braking control device for an industrial vehicle according to claim 1, wherein the control unit controls the electromagnetic retarder to regenerate power when it detects an interruption in the power supply from the power unit to the coil.

3. The aforementioned industrial vehicle is configured such that the driving force generated by the motor is transmitted to the drive wheels via the drive system. The braking control device for an industrial vehicle according to claim 1 or 2, wherein the electromagnetic retarder is provided on the side of the motor opposite to the drive system.

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