Power supply for forklift equipment

Abstract

To provide a power supply device for forklift equipment that can suppress adverse effects on the internal circuitry of the forklift when the battery is disconnected. [Solution] The power supply unit for forklift equipment comprises a first transformer, a control unit, and a current control unit. The first transformer is connected to a main power supply, which is a power source for driving the forklift and forklift equipment and is configured to be removable from the forklift body, and steps down the output voltage of the main power supply. The control unit controls the charging of the auxiliary power supply for driving 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 reverse current flow from the control unit to the first transformer.

Description

Technical Field

[0001] The present disclosure relates to a power supply device for forklift supplies.

Background Art

[0002] A battery forklift is a forklift that has a battery as the main power source for the operation of the vehicle body and operates by driving a motor with the battery. In recent years, in forklifts, supplies such as a drive recorder are often attached for management and the like. Among such supplies, there are some for which it is desirable to continue operating even when the main power source of the forklift is turned off. For this reason, forklifts equipped with a secondary power source separate from the main power source for the operation of forklift supplies have also been proposed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The battery as the main power source of the forklift is configured to be removable from the forklift body with a relatively easy operation. This is because it is stipulated to disconnect the battery for safety during specific maintenance or replacement of electrical components of the forklift. Also, since the battery can be removed with an easy operation, users who need to increase the operating amount of the forklift may use the forklift while appropriately replacing a plurality of batteries.

[0005] In this scenario, if power is supplied to the equipment from a secondary power source while the battery is disconnected from the forklift body for maintenance or replacement, it is conceivable that the output current from the secondary power source could flow back towards the forklift body. Such a backflow could adversely affect the circuitry inside the forklift body.

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

[0007] A power supply unit for forklift equipment according to one embodiment comprises a first transformer, a control unit, and a current control unit. The first transformer is connected to a main power supply, which is a power source for driving the forklift and forklift equipment and is configured to be detachable from the forklift body, and steps down the output voltage of the main power supply. The control unit controls the charging of a secondary power supply for driving 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 reverse current flow from the control unit to the first transformer. [Effects of the Invention]

[0008] In one embodiment, a power supply device for forklift equipment is provided that can suppress adverse effects on the circuitry inside the forklift when the battery is disconnected. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 shows the configuration of an example of a forklift according to an embodiment. [Figure 2] Figure 2 is a block diagram showing the configuration of the power supply unit for a forklift. [Figure 3] Figure 3 shows an example of the configuration of a power supply unit for supplies. [Modes for carrying out the invention]

[0010] The embodiments will now be described with reference to the drawings. Figure 1 is a diagram showing the configuration of an example of a forklift according to the embodiment. Here, the forklift 1 shown in Figure 1 is a counterbalanced forklift. On the other hand, the forklift according to the embodiment is not limited to a counterbalanced type as long as it is battery-powered. That is, the forklift according to the embodiment may be a reach forklift or the like. Furthermore, the forklift 1 may be a hybrid forklift consisting of a combination of an engine and a motor.

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

[0012] Furthermore, a seat 14 is attached to the vehicle body 10. A steering wheel 15 is provided in front of the seat 14. A user seated in the seat 14 can operate the steering wheel 15. The vehicle body 10 is provided with four support columns 16 surrounding the seat 14. Of the four support columns 16, for example, a display 17, which is an accessory for the forklift 1, is attached to one of the support columns 16 in front of the seat 14. Various information related to the forklift 1 can be displayed on the display 17. This information may include the charge status of the battery, the charge status of the auxiliary battery, etc.

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

[0014] Furthermore, 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 the user sitting in the seat 14. The head guard 19 may be fitted 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 photograph, for example, the area in front of the vehicle body 10. The image captured by the camera 20 may be recorded in a video recording device (not shown). Alternatively, the image captured by the camera 20 may be transmitted to a server (not shown) or the like via the wireless transceiver 24. The acceleration sensor 21 is, for example, a 3-axis acceleration sensor (XYZ) that detects acceleration along each axis generated in the vehicle body 10. The gyro sensor 22 detects angular velocity around the XYZ axes, for example. 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, gyro sensor 22, and GPS receiver 23 may be associated with the video captured by the camera 20 and recorded in a video recording device (not shown). Alternatively, the information collected by the acceleration sensor 21, gyro sensor 22, and 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 for wireless communication between the forklift 1 and a server (not shown).

[0015] Here, the accessories for forklift 1 are not limited to the display 17, camera 20, accelerometer 21, gyro sensor 22, GPS receiver 23, and wireless transceiver 24. Furthermore, the accessories for forklift 1 may include not only those originally installed on forklift 1, but also externally attached accessories such as those connected via USB (Universal Serial Bus). Moreover, they are not limited to the positions of the support column 16 or the head guard 19. The mounting positions for the accessories of forklift 1 may be any position on the vehicle body 10.

[0016] Figure 2 is a block diagram showing the configuration of the power supply unit of forklift 1. The power supply unit of forklift 1 is located inside the vehicle body 10. As shown in Figure 2, the power supply unit of forklift 1 includes a battery 101, a converter 102, and an equipment power supply unit 103.

[0017] Battery 101 is the main power source battery for the forklift 1. Battery 101 is composed of, for example, one or more lead-acid batteries. The output voltage of battery 101 is, for example, 48V. However, the output voltage of battery 101 is not limited to 48V. The output voltages of the main power sources currently prevalent in forklifts are 12V, 24V, 48V, and 72V. The output voltage of battery 101 may be any of 12V, 24V, or 72V. Also, as mentioned above, in this embodiment, battery 101 can be removed from a battery removal section 18 located on the lower side of the vehicle body 10, for example. For example, battery 101 is removed for safety reasons during certain maintenance of the forklift or replacement of electrical components. In addition, battery 101 is also removed when replacing battery 101.

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

[0019] The accessory power supply device 103 is a power supply device for driving the accessories of the forklift 1, including a secondary power supply. Therefore, the accessory power supply device 103 is connected to the accessory group 105. The accessory group 105 includes accessories of the forklift 1 such as the aforementioned display 17, camera 20, acceleration sensor 21, gyro sensor 22, GPS receiver 23, and wireless transceiver 24. The accessory power supply device 103 transforms the output voltage of the secondary battery into the voltage required for driving each accessory.

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

[0021] The input terminal is connected to the 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 the example, the first converter 201 steps down the 48V output voltage from the battery 101 to 13.8V.

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

[0023] Here, in the embodiment, the first converter 201 and the controller 202 are connected via a power supply control unit constituted by, for example, 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. Due to the operation of the diodes 203a and 203b, the reverse current from the secondary battery 204 to the input terminal when the battery 101 is disconnected from the input terminal of the power supply device is suppressed. 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 secondary 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 in the vicinity of the secondary battery 204. The temperature sensor 205a is a sensor that outputs a voltage corresponding to the temperature of the secondary 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 corresponding to the temperature generated in the temperature sensor 205a is output to a measurement circuit 205b. The measurement circuit 205b measures the temperature of the secondary battery 204 from the output voltage from the temperature sensor 205a. Also, the measurement circuit 205b is connected in parallel with the secondary battery 204 and can also measure the charging voltage of the secondary battery 204. Information on the temperature and charging voltage of the secondary battery 204 measured by the measurement circuit 205b can be displayed, for example, on the display 17. Here, in the case of an abnormally high temperature of the secondary battery 204 or the like, a warning may be displayed on the display 17, or a warning sound may be generated 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 the power switch 206. When the power switch 206 is turned on, it creates 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 it is turned off, it creates 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 on, the 12V voltage, which is the output voltage of the auxiliary battery 204, is output to the 12V output terminal and the second converter 207, respectively. The power switch 206 is the power switch for the equipment power supply unit 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 as long as the power switch 206 is on. In the event of abnormally high temperatures, the power switch 206 may be forcibly turned off.

[0026] The second converter 207 is, for example, a DC / DC converter that 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 the 5V output terminal. While the power switch 206 is on, the 5V voltage, which is the output voltage of the second converter 207, is output to the 5V output terminal.

[0027] LED208 is connected in parallel to the second converter 207 and is conductive while the power switch 206 is on, and lights up due to the current flowing during the conductive state. The user can confirm whether the power switch 206 is on or off by whether or not LED208 is lit.

[0028] Furthermore, fuses 209a, 209b, and 209c are provided at the positive output section of the first converter 201, the positive output section of the controller 202, and the positive terminal of the auxiliary battery 204, respectively. Fuses 209a, 209b, and 209c can function as protective elements to protect each component in the circuit when an excessive current flows through the circuit from any of the first converter 201, controller 202, or auxiliary battery 204.

[0029] As described above, in this embodiment, the forklift 1 is equipped with a secondary battery 204 that serves as a secondary power source for the forklift 1's accessories, in addition to the main battery 101 that serves as the main power source for driving the vehicle body 10. 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 is cut off, but even in this case, the power supply to the forklift 1's accessories from the secondary battery 204 is maintained. Therefore, the possibility of malfunctions such as resetting of date and time data and loss of digital data in the accessories is reduced. Furthermore, since the secondary battery 204 is constantly charged while the battery 101 is not removed, the possibility of insufficient output voltage of the secondary battery 204 when the battery 101 is removed can also be suppressed.

[0030] On the other hand, the presence of the auxiliary battery 204 creates a 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, for example composed of a diode, is provided on the side of the input terminal of the power supply unit. This suppresses reverse current flow from the auxiliary battery 204 to the vehicle body 10.

[0031] Furthermore, the number of products powered by USB connections has been increasing recently. In battery-powered forklifts, it is known that the voltage of the main power source, the battery, fluctuates significantly. The output voltage of a battery with such large voltage fluctuations remains large even after voltage reduction. Such voltage fluctuations can adversely affect USB-powered products that are not designed to withstand voltage fluctuations. In this embodiment, the output voltage of the main power source, battery 101, is reduced to, for example, 13.8V in the first converter 201 before charging the auxiliary battery 204. In this case, the voltage fluctuations of battery 101 are absorbed by the auxiliary battery. Since the output voltage of the auxiliary battery 204, which is 12V, is stable, it is expected that the adverse effects on USB-powered products that are not designed to withstand voltage fluctuations can be suppressed by reducing this 12V voltage to 5V.

[0032] The present invention is not limited to the embodiments described above, and can be modified in various ways during implementation without departing from its essence. Furthermore, each embodiment may be combined as appropriate, and in that case, the combined effects can be obtained. Moreover, the above embodiments include various inventions, and various inventions can be extracted by selecting combinations from the multiple constituent elements disclosed. For example, if the problem can be solved and effects obtained even if some constituent elements are deleted from all the constituent elements shown in the embodiment, then the configuration with these deleted constituent elements can be extracted as an invention. [Explanation of symbols]

[0033] 1 Forklift, 10 Body, 11 Mast, 12 Forks, 13 Counterweight, 14 Seat, 15 Steering Wheel, 16 Support Column, 17 Display, 18 Battery Removal Port, 19 Head Guard, 20 Camera, 21 Accelerometer, 22 Gyroscope, 23 GPS Receiver, 24 Wireless Transmitter / Receiver, 101 Battery, 102 Converter, 103 Power Supply Unit for Accessories, 104 Drive Motor, 105 Accessories Group, 201 First Converter, 202 Controller, 203a, 203b Diodes, 204 Sub-Battery, 205a Temperature Sensor, 205b Measurement Circuit, 206 Power Switch, 207 Second Converter, 208 LED, 209a, 209b, 209c Fuses.

Claims

1. A first transformer connected to a main power supply that is detachably configured from the forklift body and is used to drive a forklift and its accessories, the first transformer which steps down the output voltage of the main power supply, A control unit that controls the charging of a secondary power supply for driving the equipment of the forklift using the voltage stepped down by the first transformer, A current control unit is provided between the first transformer and the control unit to suppress reverse current flow from the control unit to the first transformer, A power supply unit for forklift equipment equipped with the following.

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. The power supply device for forklift equipment according to claim 1, further comprising a second transformer connected to the auxiliary power supply and for reducing the output voltage of the auxiliary power supply.

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

5. The power supply device for the forklift equipment according to any one of claims 1 to 4, wherein the forklift equipment includes a camera, sensors, and a wireless communication device installed on the forklift.

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