Power supply for forklift equipment

Abstract

To provide a power supply device for forklift equipment capable of suppressing adverse effects on circuits in the body of the forklift when a battery is disconnected. [Solution] A power supply device for forklift equipment includes a first transformer, a control unit, and a current control unit. The first transformer is connected to a main power supply that is configured to be removable from the forklift body and is used to drive the forklift and the forklift equipment, and steps down the output voltage of the main power supply. The control unit controls charging of a secondary power supply that drives the forklift equipment with the voltage stepped down by the first transformer. The current control unit is provided between the first transformer and the control unit, and suppresses backflow from the control unit to the first transformer.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to a power supply for forklift equipment. [Background technology]

[0002] A battery forklift is a forklift that is equipped with a battery as the main power source for the vehicle's operation and that operates by driving a motor using the battery. Recently, forklifts have increasingly been equipped with devices such as drive recorders for management purposes. Some of these devices are desirable to continue operating even when the forklift's main power source is turned off. For this reason, forklifts equipped with a secondary power source separate from the main power source for operating the forklift's devices have also been proposed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-195755 Summary of the Invention [Problem to be solved by the invention]

[0004] The battery, which serves as the main power source for a forklift, is designed to be removable from the forklift body with relatively little effort. This is because, for safety reasons, it is required to disconnect the battery when performing specific maintenance or replacing electrical parts on the forklift. Furthermore, because the battery can be easily removed, users who need to increase the operating rate of their forklifts may use multiple batteries while switching them as needed.

[0005] If the auxiliary power supply supplies power to the equipment while the battery is disconnected from the forklift body for maintenance or replacement, it is possible that the output current from the auxiliary power supply will flow back toward the forklift body, which could adversely affect the circuits inside the forklift body.

[0006] The embodiment provides a power supply device for forklift equipment that can suppress adverse effects on circuits within the forklift body when the battery is disconnected. [Means for solving the problem]

[0007] In one aspect, a power supply device for a forklift includes a first transformer, a control unit, and a current control unit. , a sensor, and a measurement circuit The first transformer is connected to a main power supply that is configured to be removable from the forklift body and is used to drive the forklift and equipment on the forklift, and steps down the output voltage of the main power supply. The control unit controls charging of a secondary power supply that is used to drive the forklift equipment using the voltage stepped down by the first transformer and is connected so that conduction with the forklift equipment is maintained even when the main power supply is turned off. The current control unit is provided between the first transformer and the control unit, and limits the current flowing from the first transformer to the control unit and suppresses backflow from the control unit to the first transformer. The sensor is provided near the secondary power supply and outputs a voltage corresponding to the temperature of the secondary power supply. The measurement circuit is connected in parallel to the secondary power supply and measures the temperature of the secondary power supply from the voltage of the sensor and the charging voltage of the secondary power supply. [Effects of the Invention]

[0008] In an embodiment, a power supply device for forklift equipment is provided that can suppress adverse effects on circuits within the forklift body when the battery is disconnected. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of a configuration of a forklift according to an embodiment. [Figure 2] FIG. 2 is a block diagram showing the configuration of a power supply device for a forklift. [Figure 3] FIG. 3 is a diagram illustrating a configuration of an example of an accessory power supply device. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing the configuration of an example of a forklift according to an embodiment. Here, the forklift 1 shown in FIG. 1 is a counter-load forklift. However, the forklift according to the embodiment is not limited to a counter-load forklift as long as it is battery-powered. In other words, the forklift according to the embodiment may be a reach forklift or the like. Furthermore, the forklift 1 may be a hybrid forklift that combines an engine and a motor.

[0011] The forklift 1 shown in Fig. 1 has a vehicle body 10. A mast 11 is attached to the front of the vehicle body 10. Forks 12 are attached to the mast 11. The forks 12 are raised and lowered along the mast 11 by operation of a user who is the driver of the forklift 1. In addition, a counterweight 13 is provided at the rear of the vehicle body 10. The counterweight 13 is provided to balance the forks 12 with a load when the load is placed on them.

[0012] A seat 14 is also attached to the vehicle body 10. A steering wheel 15 is provided in front of the seat 14. A user sitting in the seat 14 can operate the steering wheel 15. Four support pillars 16 are provided on the vehicle body 10 so as to surround the seat 14. A display 17, which is an accessory of the forklift 1, is attached to one of the four support pillars 16, for example, the one in front of the seat 14. Various types of information related to the forklift 1 can be displayed on the display 17. The various types of information can include the charge status of the battery, the charge status of the auxiliary battery, etc.

[0013] Furthermore, a battery removal port 18 is provided at a lower lateral position of the vehicle body 10, for example, at a lower lateral position of the seat 14 in the vehicle body 10. The battery removal port 18 is configured to be openable and closable. By opening the battery removal port 18, the battery inside the vehicle body 10 can be removed.

[0014] A head guard 19 is provided on the top of the four support columns 16. The head guard 19 is a guard member for protecting the head of a user seated in the seat 14. The head guard 19 may be equipped with accessories for the forklift 1, such as a camera 20, an acceleration sensor 21, a gyro sensor 22, a GPS (Global Positioning System) receiver 23, and a wireless transceiver 24. The camera 20 is provided to capture, for example, an image in front of the vehicle body 10. Images captured by the camera 20 may be recorded in a video recording device (not shown). Alternatively, the images captured by the camera 20 may be transmitted to a server (not shown) via the wireless transceiver 24. The acceleration sensor 21 is, for example, a three-axis (X, Y, Z) acceleration sensor that detects accelerations along each axis occurring in the vehicle body 10. The gyro sensor 22 detects, for example, angular velocity around the X, Y, and Z axes. The GPS receiver 23 collects position information of the forklift 1 by receiving radio waves from a base station (not shown). The information collected by the acceleration sensor 21, the gyro sensor 22, and the GPS receiver 23 may be recorded in a video recording device (not shown) in association with the video captured by the camera 20. Alternatively, the information collected by the acceleration sensor 21, the gyro sensor 22, and the GPS receiver 23 may be transmitted to a server (not shown) or the like via a wireless transceiver 24. The wireless transceiver 24 is a device that enables the forklift 1 to wirelessly communicate with a server (not shown) or the like.

[0015] Here, the equipment of the forklift 1 is not limited to the display 17, camera 20, acceleration sensor 21, gyro sensor 22, GPS receiver 23, and wireless transceiver 24. Furthermore, the equipment of the forklift 1 may include not only equipment that is originally installed on the forklift 1, but also equipment that can be externally attached via a USB (Universal Serial Bus) connection or the like. Furthermore, the equipment is not limited to the position of the support 16 or the head guard 19. The attachment position of the equipment of the forklift 1 may be any position on the vehicle body 10.

[0016] Fig. 2 is a block diagram showing the configuration of the power supply device of the forklift 1. The power supply device of the forklift 1 is provided inside the vehicle body 10. As shown in Fig. 2, the power supply device of the forklift 1 has a battery 101, a converter 102, and an accessory power supply device 103.

[0017] The battery 101 is a battery that serves as the main power source for the forklift 1. The battery 101 is, for example, composed of one or more lead-acid batteries. The output voltage of the battery 101 is, for example, 48 V. However, the output voltage of the battery 101 is not limited to 48 V. The output voltages of the main power sources that are currently mainstream in forklifts are 12 V, 24 V, 48 V, and 72 V. The output voltage of the battery 101 may be any of 12 V, 24 V, and 72 V. As described above, in this embodiment, the battery 101 can be removed from the battery removal port 18 provided, for example, at a lower lateral position of the vehicle body 10. For example, the battery 101 is removed for safety reasons when performing specific maintenance on the forklift or replacing electrical components. The battery 101 is also removed when replacing the battery 101.

[0018] The converter 102 is connected to the battery 101. The converter 102 is a converter for driving the body 10 of the forklift 1. Therefore, the converter 102 is connected to a drive motor 104. The drive motor 104 may include a travel motor for driving the body 10, a power steering motor for steering the body 10, and a cargo motor for raising and lowering the forks 12. The converter 102 transforms the output voltage of the battery 101 into a voltage required to drive each motor.

[0019] The equipment power supply device 103 is a power supply device for driving equipment, including the auxiliary power supply, of the forklift 1. Therefore, the equipment power supply device 103 is connected to an equipment group 105. The equipment group 105 is equipment of the forklift 1, such as the display 17, camera 20, acceleration sensor 21, gyro sensor 22, GPS receiver 23, and wireless transceiver 24 mentioned above. The equipment power supply device 103 converts the output voltage of the auxiliary battery to a voltage required to drive each of the equipment.

[0020] Next, the equipment power supply device 103 will be described. FIG. 3 is a diagram showing the configuration of an example of the equipment power supply device 103. The equipment power supply device 103 has an input terminal (input) and an output terminal (output). The output voltage of the battery 101 is applied to the input terminal. In the example of FIG. 3, the output voltage of the battery 101 is 48 V. On the other hand, a voltage is applied to the equipment group 105 from the output terminal. Here, in the embodiment, the output terminals include a 12 V output terminal and a 5 V output terminal. The 12 V output terminal is an output terminal for equipment mounted on the vehicle body 10. On the other hand, the 5 V output terminal is an output terminal for equipment externally attached via a USB terminal.

[0021] The input terminal is connected to a first converter 201. The first converter 201 is, for example, a DC / DC converter, and steps down the output voltage of the battery 101. In this example, the first converter 201 steps down the output voltage of 48V from the battery 101 to 13.8V.

[0022] The first converter 201 is connected to a controller 202. The controller 202 is a circuit for controlling charging of the secondary battery 204. The controller 202 controls the voltage applied to the secondary battery 204 so that the secondary battery 204 is charged within a predetermined range from a charging start voltage to a charging end voltage. Furthermore, if the temperature of the secondary battery 204 exceeds a threshold value, the controller 202 determines that the temperature is abnormally high and forcibly stops charging.

[0023] In this embodiment, the first converter 201 and the controller 202 are connected via a power supply control unit configured, for example, with two diodes 203a and 203b connected in parallel. The anodes of the diodes 203a and 203b are connected to the first converter 201, and the cathodes of the diodes 203a and 203b are connected to the controller 202. The diodes 203a and 203b act to suppress reverse current flow from the secondary battery 204 to the input terminal when the battery 101 is disconnected from the input terminal of the power supply device. Here, the diodes 203a and 203b may be constant current diodes. If they are constant current diodes, the current flowing from the first converter 201 to the controller 202 is limited to a constant value.

[0024] The auxiliary battery 204 is, for example, a 12V lead battery, and is charged by the output voltage of the first converter 201. A temperature sensor 205a is provided near the auxiliary battery 204. The temperature sensor 205a outputs a voltage corresponding to the temperature of the auxiliary battery 204. The temperature sensor 205a may be a non-contact sensor that detects radiant heat, or a contact sensor such as a thermocouple or a thermistor. The voltage generated by the temperature sensor 205a and corresponding to the temperature is output to a measurement circuit 205b. The measurement circuit 205b measures the temperature of the auxiliary battery 204 from the output voltage from the temperature sensor 205a. The measurement circuit 205b is also connected in parallel to the auxiliary battery 204 and can measure the charging voltage of the auxiliary battery 204. Information on the temperature and charging voltage of the auxiliary battery 204 measured by the measurement circuit 205b can be displayed on the display 17, for example. Here, if the secondary battery 204 becomes abnormally high temperature, a warning may be displayed on the display 17 or a warning sound may be emitted from a speaker attached to the display 17.

[0025] The auxiliary battery 204 is connected to the second converter 207 and the 12V output terminal via a power switch 206. When the power switch 206 is turned on, it establishes a conductive state between the auxiliary battery 204 and the 12V output terminal and between the auxiliary battery 204 and the second converter 207. When the power switch 206 is turned off, it establishes a non-conductive state between the auxiliary battery 204 and the 12V output terminal and between the auxiliary battery 204 and the second converter 207. In other words, while the power switch 206 is turned on, the 12V voltage that is the output voltage of the auxiliary battery 204 is output to the 12V output terminal and the second converter 207. The power switch 206 is a power switch for the accessory power supply device 103, and is configured to be turned on and off independently of the main power switch of the forklift 1 (not shown). In other words, even if the main power switch of the forklift 1 is turned off, the conductive state between the auxiliary battery 204 and the second converter 207 is maintained while the power switch 206 is turned on. Here, in the event of an abnormally high temperature, the power switch 206 can be forced to turn off.

[0026] The second converter 207 is, for example, a DC / DC converter, and steps down the output voltage of the auxiliary battery 204. In this example, the second converter 207 steps down the 12V output voltage from the auxiliary battery 204 to 5V. The second converter 207 is connected to a 5V output terminal. While the power switch 206 is on, the 5V voltage that is the output voltage of the second converter 207 is output to the 5V output terminal.

[0027] The LED 208 is connected in parallel to the second converter 207, is in a conductive state while the power switch 206 is on, and emits light due to the current that flows while in the conductive state. Depending on whether the LED 208 emits light or not, the user can confirm whether the power switch 206 is on or not.

[0028] Fuses 209a, 209b, and 209c are provided respectively at the positive output of the first converter 201, the positive output of the controller 202, and the positive terminal of the secondary battery 204. The fuses 209a, 209b, and 209c can function as protective elements for protecting the elements in the circuit when an excessive current flows through the circuit from any of the first converter 201, the controller 202, and the secondary battery 204.

[0029] As described above, in the embodiment, the forklift 1 includes the battery 101, which serves as the main power source for driving the vehicle body 10, as well as the auxiliary battery 204, which serves as the auxiliary power source for driving the equipment of the forklift 1. The battery 101 can be removed from the vehicle body 10 of the forklift 1 for battery replacement or maintenance. When the battery 101 is removed from the vehicle body 10, the main power source is cut off, but even in this case, the power supply from the auxiliary battery 204 to the equipment of the forklift 1 is maintained. This reduces the possibility of problems occurring in the equipment, such as resetting the date and time data and losing digital data. Furthermore, because the auxiliary battery 204 is constantly charged while the battery 101 is not removed, the possibility of the output voltage of the auxiliary battery 204 being insufficient when the battery 101 is removed can also be reduced.

[0030] On the other hand, the presence of the auxiliary battery 204 raises the risk of reverse current flow from the auxiliary battery 204 to the vehicle body 10 when the battery 101 is disconnected. In response to this, in this embodiment, a current control unit constituted by, for example, a diode is provided on the input terminal side of the accessory power supply device. This prevents reverse current flow from the auxiliary battery 204 to the vehicle body 10.

[0031] Recently, the number of products powered by USB connections has also been increasing. It is known that the voltage fluctuations of the battery, which serves as the main power source, are large in battery forklifts. The output voltage of such a battery with large voltage fluctuations remains large even after being stepped down. Such voltage fluctuations may adversely affect USB-powered products for which voltage fluctuations are not anticipated. In response to this, in this embodiment, the output voltage of the battery 101, which serves as the main power source, is dropped to, for example, 13.8 V in the first converter 201 before charging the auxiliary battery 204. In this case, the voltage fluctuations of the battery 101 are absorbed by the auxiliary battery. Because the output voltage of the auxiliary battery 204 is stable at 12 V, dropping this 12 V voltage to 5 V is expected to reduce adverse effects on USB-powered products for which voltage fluctuations are not anticipated.

[0032] The present invention is not limited to the above-described embodiments, and various modifications can be made in the implementation stage without departing from the spirit of the invention. Furthermore, the embodiments may be implemented in appropriate combinations, in which case the combined effects can be obtained. Furthermore, the above-described embodiments include various inventions, and various inventions can be extracted by combining selected elements from the disclosed elements. For example, if the problem can be solved and the desired effect can be obtained even if some elements are deleted from all elements shown in the embodiments, the configuration from which these elements are deleted can be extracted as an invention. [Explanation of symbols]

[0033] 1 forklift, 10 body, 11 mast, 12 fork, 13 counterweight, 14 seat, 15 steering wheel, 16 support, 17 display, 18 battery outlet, 19 head guard, 20 camera, 21 acceleration sensor, 22 gyro sensor, 23 GPS receiver, 24 radio transceiver, 101 battery, 102 converter, 103 equipment power supply device, 104 drive motor, 105 equipment group, 201 first converter, 202 controller, 203a, 203b diode, 204 auxiliary battery, 205a temperature sensor, 205b measurement circuit, 206 power switch, 207 second converter, 208 LED, 209a, 209b, 209c fuse.

Claims

1. a first transformer connected to a main power supply for driving a forklift and equipment mounted on the forklift and configured to be removable from the body of the forklift, the first transformer stepping down an output voltage of the main power supply; a control unit that controls charging of a secondary power supply that is a power supply for driving equipment of the forklift using the voltage stepped down by the first transformer and is connected so that a conductive state between the secondary power supply and the equipment of the forklift is maintained even when the main power supply is turned off; a current control unit provided between the first transformer and the control unit, and configured to suppress backflow from the control unit to the first transformer; a sensor provided near the secondary power supply and configured to output a voltage corresponding to a temperature of the secondary power supply; a measurement circuit connected in parallel to the auxiliary power supply, for measuring a temperature of the auxiliary power supply from a voltage of the sensor and for measuring a charging voltage of the auxiliary power supply; A power supply for forklift equipment comprising:

2. 2. The power supply device for forklift equipment according to claim 1, wherein the output voltage of the main power supply is 24V or 48V, and the voltage stepped down by the first transformer is 13.8V.

3. 2. The power supply device for forklift equipment according to claim 1, further comprising a second transformer connected to said secondary power supply for stepping down the output voltage of said secondary power supply.

4. 4. The power supply device for forklift equipment according to claim 3, wherein the voltage stepped down by said second transformer is 5V.

5. 5. The power supply device for forklift equipment according to claim 1, wherein the forklift equipment includes a camera, a sensor and a wireless communication device installed on the forklift.

6. The current control unit further limits the current flowing from the first transformer to the control unit.

10. A power supply for a forklift equipment according to claim 1.

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