JP4840873B2 - Work vehicle - Google Patents

Description

  The present invention relates to a work vehicle using a battery as a drive source.

  Conventionally, a battery forklift using a battery as a driving source is known (for example, Patent Document 1). Such a forklift is provided with a regenerative braking device (generally a case where a traveling electric motor functions as a generator) that generates regenerative energy during braking, and stores the regenerative energy back to the battery. Yes. However, as a battery, the regenerative energy cannot always be efficiently stored, and the rate of loss due to heat generation is large. For this reason, it has been proposed to mount a capacitor capable of efficiently storing electricity separately from the battery and to store regenerative energy exclusively in the capacitor.

  In addition to the regenerative energy from the regenerative braking device, such a capacitor is automatically charged in the capacitor in the form of precharging from the battery. This precharging is automatically started when the key switch is turned on when the operator starts work.

JP 2006-264940 A

  However, during the precharge, power is not supplied to the main controller that controls the electric motor for traveling, the electric motor for driving the work machine (hydraulic pump), and the like, and the forklift cannot be operated. For this reason, the operator cannot immediately grasp why it does not operate and is confused. Moreover, since precharging is performed only when the voltage of the capacitor is lower than the voltage of the battery and the difference exceeds a predetermined value, it is recognized that precharging has normally started unless such a situation occurs. It is not easy to do.

  The objective of this invention is providing the work vehicle which can make an operator grasp | ascertain reliably that it is precharging.

  A work vehicle according to claim 1 of the present invention includes a battery, a capacitor electrically connected to the battery via a system voltage line, a means for shutting off the line provided in the system voltage line, and a shut-off state. A precharge circuit that electrically connects the battery and the capacitor by bypassing the line blocking means, and a state notification means for notifying a state in which precharge from the battery side to the capacitor side is performed And a voltage comparing means for comparing the voltage on the battery side and the voltage on the capacitor side, and generating a control signal for starting or stopping the precharging according to the comparison result in the voltage comparing means. A precharge signal generating means for outputting to the charging circuit, a state signal generating means for generating a state signal when precharge is being performed and outputting it to the state notification means, and the voltage ratio If the pre-charge is determined to be unnecessary by the comparison result in the device, characterized in that it comprises a conduction control means for conducting the line blocking unit the system voltage line and controls the.

    A work vehicle according to a second aspect is the work vehicle according to the first aspect, further comprising a power supply controller that controls charging / discharging of the battery, the voltage comparison unit, the precharge signal generation unit, and the state signal generation unit. And the continuity control means is provided in a control unit of the power supply controller.

    A work vehicle according to a third aspect is the work vehicle according to the second aspect, further comprising a key switch that activates a control unit of the power supply controller, wherein the control unit includes the key switch in an on position or an off position. A key position determining means for determining whether the precharge is unnecessary according to the comparison result of the voltage comparing means, and the key position determining means When it is determined that the switch is in the ON position, a state signal indicating that charging of the capacitor is in a normal state is generated and output to the state notification means, and when it is determined that precharging is unnecessary, and When it is determined that the key switch is in the OFF position, the notification operation by the state notification unit is stopped.

  According to the first aspect of the present invention, when the voltage of the capacitor is significantly smaller than the voltage at the battery, precharging from the battery to the capacitor is automatically performed. At this time, since the operator is notified by the state notification means that the precharge is being performed, the operator can easily grasp that the work vehicle does not operate because of the precharge, and may be confused. Absent.

  According to the second aspect of the present invention, the voltage comparison means, the precharge signal generation means, the state signal generation means, and the conduction control means are provided in the power supply controller and are provided as a function of the power supply controller. The precharge from the battery to the capacitor and the status notification can be centrally controlled by the CPU or the like of the power supply controller, and the system configuration can be simplified.

  According to the third aspect of the present invention, when the work is performed following the precharge, the key switch is in the ON position, so that the normal state can be notified by the state notification means, and the normal state is recognized. Work with confidence. In addition, even if pre-charging is completed, if the key switch does not work immediately, the key switch is in the off position, and the notification by the status notification means is stopped. Can be promoted.

[Configuration of forklift]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a side view showing an entire forklift 10 as a work vehicle according to the present embodiment. The forklift 10 is a four-wheel type equipped with left and right front wheels 12 and rear wheels 13 on the front and rear of a vehicle body 11, respectively, and is a battery forklift driven by electric energy from a battery. However, the forklift of the present invention may be a three-wheel type having only one rear wheel 13.

  On the front side of the vehicle body 11, a work machine 14 for cargo handling is provided. The work machine 14 has a mast 15 erected vertically, a fork claw 16 that moves up and down along the mast 15, a lift cylinder 17 that drives the fork claw 16 up and down, and an entire work machine 14 with respect to the vehicle body 11. And a tilt cylinder 18 that tilts back and forth within an angular range.

  The vehicle body 11 is provided with a driver seat 19 for an operator to sit on. The upper side of the driver seat 19 is covered with a head guard 20 attached on the vehicle body 11. The driver's seat 19 is provided integrally with the lower hood panel 21. The hood panel 21 is provided so as to be openable and closable up and down, and a battery unit 30 is accommodated below the hood panel 21. Further, as shown in FIG. 3, a work machine operation lever 27 for lift operation and tilt operation, an emergency button 28 for emergency stop are provided on the side of the driver's seat 19, and further, a status display means 40 is provided. Is provided. The battery unit 30 can be slid in the horizontal direction with respect to the vehicle body 11 by opening and closing a side panel that can also be opened and closed, and can be easily attached and detached.

  A counterweight 22 is provided on the rear side of the vehicle body 11. The space inside the counterweight 22 accommodates a main controller 23, a capacitor 24, and the like. The main controller 23 supplies the electric energy from the battery unit 30 to the electric motor 25 for driving the front wheels 12 (FIG. 4) and the electric motor 26 for the work implement 14 (FIG. 4). In particular, since the capacitor 24 has a relatively large weight, the capacitor 24 has a role as a part of the counterweight 22 by being accommodated in the counterweight 22.

  Here, as shown in FIG. 2, the battery unit 30 includes a battery unit main body 32 configured to include a bottomed box-shaped battery case 31, and a power supply controller 33 mounted on the battery unit main body 32. Yes. The battery unit main body 32 has a structure in which a total of 24 batteries 34 are accommodated in three upper and lower stages. In each stage of the battery body 32, four batteries 34 are connected in series to form one module, and two modules are arranged. In addition to the bottomed shape, the battery case 31 may have a bottomed shape as long as there is no problem in terms of strength and layout, or may be a hanging type or a cage type. Further, the number of the batteries 34 is arbitrary, and may be determined in consideration of an output voltage required for the entire system of the forklift 10, an output voltage of the battery 34 alone, or the like.

  The output voltage of one battery 34 is 12V, so the voltage at each module is 48V. In FIG. 2, the battery 34 is indicated by a two-dot chain line. Electric power from a pair of modules arranged in each stage is input to first to third power supply circuits 74 to 76 (FIG. 4) provided in the power supply controller 33.

  In addition, the state display means 40 is a hood required when the forklift 10 is charged before the main controller 23 is activated, when the battery unit main body 32 and the capacitor 24 are electrically connected, or when charged by an external power source. It is a device that displays a state relating to the opening and closing of the panel 21, and includes a red LED 40A and a green LED 40B that is a state notification means. Note that the status notification means is not limited to a light emitting element such as an LED as in the present embodiment, but may be a means using an alarm, sound, or the like.

  The function of the status display means 40 will be specifically described. When charging the battery unit main body 32 from an external power source, it is necessary to open the hood panel 21 to promote ventilation around the battery unit main body 32, and when it is determined that the battery unit main body 32 is not open. The red LED 40A lights up. The battery unit main body 32 and the capacitor 24 are connected via a connector 63 (FIG. 4). If the connector 63 is disconnected, precharging from the battery unit main body 32 to the capacitor 24 cannot be performed. Also when red is detected, the red LED 40A is lit.

  Further, when the operator operates the key switch for starting the system to the on position at the start of work, the power supply controller 33 is started, and the voltage on the capacitor 24 side and the voltage on the battery unit body 32 side are compared to determine the charged state. When pre-charging is necessary, pre-charging is automatically started, and the fact that pre-charging is in progress is displayed by blinking of the green LED 40B. If the key switch is in the on position at the stage where the precharge is completed, the green LED 40B is turned on, and if the key switch is in the off position, the green LED 40B is turned off. When the charge amount of the capacitor 24 is sufficient from the beginning and the precharge is unnecessary, the green LED 40B is turned on when the key switch is operated to the ON position.

[Forklift system configuration]
Next, the system configuration of the forklift 10 will be described below with a focus on the power supply controller 33. FIG. 4 is a block diagram showing the entire system.

  The power supply controller 33 of the forklift 10 is provided with a DC 48V system voltage line 62 to which a power supply line from the battery unit main body 32 is connected. The system voltage line 62 is connected to the main controller 23, the capacitor 24, the proportional valve controller 64, and the meter panel 65 via the connector 63, and supplies power from the battery unit 30.

  The main controller 23 controls the electric motor 25 for driving the front wheel 12 (FIG. 1) based on an operation signal from a travel accelerator pedal (not shown), and also controls the electric motor 26 for driving the hydraulic pump 66. Yes. The hydraulic pump 66 supplies hydraulic pressure to the lift cylinder 17 and the tilt cylinder 18 via the proportional valve 67. Further, when the electric motor 26 functions as a generator, the main controller 23 sends the electric energy regenerated by the electric motor 26 to the capacitor 24 to be stored.

  The capacitor 24 has a characteristic capable of efficiently collecting, storing and discharging a large current generated instantaneously, and can utilize regenerative energy without loss. Thus, the capacitor 24 functions as a power source together with the battery unit 30 and assists in driving the electric motors 25 and 26. In other words, this system is a battery hybrid having two power sources, that is, the battery unit 30 side and the capacitor 24 side.

  The proportional valve controller 64 energizes the solenoid of the proportional valve 67 based on the operation signal from the work machine operation lever 27 to switch the spool position of the proportional valve 67. As a result, the cylinders 17 and 18 can be expanded and contracted by the hydraulic pressure from the hydraulic pump 66 to perform the cargo handling operation.

  A battery charging line 68 is also connected to the system voltage line 62 of the power controller 33. External power from the AC input unit 69 is input to the charging line 68 via the charge contactor 71. The input AC power is converted to DC by the converter 72, and is stepped down to a charging voltage by the transformer 73 and energized to the system voltage line 62.

  Power lines from the first to third power supply circuits 74 to 76 are connected to the system voltage line 62 in parallel. Charging of the power input through the system voltage line 62 and discharging from the battery unit main body 32 to the system voltage line 62 are performed by the first to third power supply circuits 74 to 76 in the power supply controller 33 and a control unit 77 including a CPU. Be controlled.

  In addition to various means for controlling charging / discharging, the control unit 77 includes a voltage comparison means 81, a precharge signal generation means 82, a state signal generation means 83, a key operation determination means 84, and continuity control, which are unique to this embodiment. Means 85 are provided. Each of these means 81 to 85 is actually software executed in the control unit 77, and causes the state display means 40 to display according to the situation, and also controls the start and stop of precharging. .

  The precharge will be described again. When the system is turned on by operating the key switch to the on position, first, the control unit 77 detects and compares the voltage on the capacitor 24 side and the voltage on the battery unit body 32 side, and the voltage on the capacitor 24 side is compared with the battery unit. When the voltage is lower than the voltage on the main body 32 side and the difference is larger than the specified value, the disconnected state of the opened main contactor 95 is maintained as it is. This is because if the main contactor 95 is energized while the voltage on the capacitor 24 side is low, current may flow from the battery unit body 32 to the capacitor 24 at a stretch, and damage may occur at the contacts on the electric circuit.

  Therefore, it is necessary to charge the capacitor 24 to reduce the voltage difference (potential difference) from the battery unit main body 32 side while maintaining the main contactor 95 in the open state. Charging at this time is precharging. For this reason, in the present embodiment, a precharge circuit 86 that bypasses the main contactor 95 in the open state is provided, and a minute current flows through the precharge circuit 68, so that the capacitor 24 is charged from the battery unit main body 32. The voltage difference between the two is reduced. If precharge is not performed and the voltage on the capacitor 24 side remains low, the main controller 23 and the meter panel 65 do not start, and the forklift 10 does not operate. The state display means 40 is provided so that the operator can easily grasp that pre-charging is being performed.

Each means 81-85 of the control part 77 is demonstrated concretely.
The voltage comparison unit 81 has a function of constantly comparing the voltage on the battery unit main body 32 side with the voltage of the capacitor 24.
The precharge signal generating means 82 outputs a control signal to the precharge circuit 86 according to the comparison result of the voltage comparison means 81, and controls the start and stop of precharge.

  The state signal generation unit 83 outputs a state signal for blinking the green LED 40B to the LED 40B while precharging is performed, and the precharging is completed or the capacitor 24 is sufficiently charged from the beginning. If it is, a status signal for lighting the green LED 40B is output. In addition, the state signal generation means 83 also has a function of outputting a state signal for lighting the red LED 40A when there is an abnormality in the open / close state of the hood panel 21 or the connection state of the connector 63.

The key position determination means 84 determines whether the key switch is in the on position or the off position (including the case where the key is removed) as a result of the key operation by the operator.
The conduction control means 85 outputs a signal for conducting the system voltage line 62 to the main contactor 95 when the charged amount of the capacitor 24 is sufficient and the key switch is in the ON position. Conversely, when it is determined that precharging is necessary, including during precharging, and when the key switch is in the OFF position, the key position determining means 84 opens the main contactor 95 and shuts off the system voltage line 62. To.

  In the present embodiment, the precharge switch 91, the charging operation panel 92, and the hood switch 94 are connected to the control unit 77 of the power supply controller 33 in addition to the state display unit 40.

  The precharge switch 91 is a switch for performing precharge from the battery unit main body 32 to the capacitor 24. As described above, the precharge is normally automatically started when it is determined to be necessary at the stage where the voltages are compared. The precharge switch 91 is used when the precharge is performed at the operator's discretion. To be treated. The case where the determination is performed by the operator is, for example, a case where the battery unit body 32 intentionally stores power from the battery unit 32 to the capacitor 24 regardless of the voltage difference.

  In the present embodiment, the control unit 77 determines the connection state of the connector 63 when the precharge switch 91 is operated. When it is determined that the connection is not established, the state signal generation unit 83 outputs an alarm signal to the state display unit 93 and turns on the red LED 40A as described above. This is the same even when precharging is performed automatically.

  The charging operation panel 92 is operated when charging the battery unit main body 32 through the AC input unit 69. Charging is started by operating the charging switch of the charging operation panel 92. The state of charge, such as the amount of charge, can be determined by lighting an LED or the like provided on the charging operation panel 92. Further, when the capacitor 24 cannot be charged, such as when the connector 63 is not connected, as described above, the red LED 40A notifying abnormality is turned on.

  The hood switch 94 is a switch that detects the open / closed state of the hood panel 21, and includes a limit switch, a proximity sensor, and the like that operate in accordance with the movement of the hinge for opening and closing. When the hood switch 94 is in the ON state, it is determined that the hood panel 21 is open, and charging from the external power source to the battery unit main body 32 is permitted. On the other hand, when the hood switch 94 is in the off state, it is determined that the hood panel 21 is closed. Therefore, the ventilation is not performed well. Therefore, the control unit 77 sends a cutoff signal to the charge contactor 71. The status signal generation means 83 outputs an alarm signal to the status display means 93, and the red LED 40A is turned on as described above.

[Flow during pre-charging]
Next, the state of precharging at the start of work will be described below with reference to FIG.
When the operator turns the key switch to the ON position, the control unit 77 of the power controller 33 is activated. At this stage, the main contactor 95 is in an open state. First, the voltage comparison means 81 of the control unit 77 compares the battery voltage Vb on the battery unit main body 32 side (synonymous with the battery 34 side) and the capacitor voltage Vc on the capacitor 24 side, and the difference is greater than or equal to the specified value N. Is also determined whether it is larger (S1).

  If it is larger, the precharge signal generating means 82 outputs a control signal to the precharge circuit 86 to start precharge (S2). Further, the state signal generating unit 83 outputs a state signal for blinking the green LED 40B (S3). Accordingly, pre-charging is started at the start of work, and even if the main contactor 95 is kept open so that the main controller 23 or the like does not start, the operator immediately confirms that the forklift 10 does not operate because of the start of pre-charging. There is no worry about being confused.

  On the other hand, if the difference between the voltages Vb and Vc is smaller than the specified value N in S2, it is determined that the precharge has been sufficiently performed, and the precharge signal generator 82 controls the precharge circuit 86 to stop the precharge. A signal is output and stopped (S4). In addition, even when the charge amount of the capacitor 24 is sufficient from the beginning, naturally, the flow is on the S4 side, and the precharge is not performed. Next, the key position determination means 84 detects the position of the key switch in a state where the precharge is stopped or not performed from the beginning (S5).

  If the key switch is in the OFF position, the status signal generation means 83 stops outputting the status signal to the green LED 40B, turns it off, and stops the notification operation (S6). As such a situation, for example, an operator who recognizes that precharging has started at the start of work is assumed to leave the forklift 10 by removing the key until completion of precharging. In other words, in this embodiment, even when the key switch is in the off position or the key is removed from the key switch, once the precharge is started, it does not stop until completion.

  On the other hand, when the key switch is in the ON position in S5, the state signal generation unit 83 outputs a state signal for lighting the green LED 40B to the state display unit 40, the precharge is completed, and the capacitor 24 is normal. The operator recognizes that it is in a state (S7). As such a situation, for example, an operator who has recognized that precharging has started at the start of work has left the key switch in an on state, or the capacitor 24 has been in a normal state from the beginning. It is assumed that the precharge is not performed and the operation is started as it is.

  Thereafter, the conduction control means 85 outputs a control signal to the main contactor 95 and electrically connects the battery unit main body 21 side and the capacitor 24 side to the main controller 23, the proportional valve controller 64, and the meter panel 65. Electric power is supplied to start up, and the forklift 10 is made operable.

The best configuration, method, and the like for carrying out the present invention have been disclosed above, but the present invention is not limited to this. That is, the invention has been illustrated and described with particular reference to certain specific embodiments, but without departing from the spirit and scope of the invention, Various modifications can be made by those skilled in the art in terms of quantity and other detailed configurations.
Therefore, the description limited to the shape, quantity and the like disclosed above is an example for easy understanding of the present invention, and does not limit the present invention. The description by the name of the member which remove | excluded the limitation of one part or all of such restrictions is included in this invention.

  For example, the forklift 10 of the above embodiment is a counter type provided with the counterweight 21, but the present invention is not limited to this, and the present invention may be applied to a reach type forklift.

  The present invention can be used for work vehicles such as a forklift driven by electric energy from a battery, a small hydraulic excavator, and a wheel loader.

The side view which shows the whole working vehicle which concerns on one Embodiment of this invention. The disassembled perspective view which decomposes | disassembles and shows a part of battery unit. The perspective view which shows the principal part of a work vehicle. The block diagram which shows the whole system of a working vehicle. The flowchart for demonstrating the flow at the time of precharge.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Forklift which is a working vehicle, 24 ... Capacitor, 32 ... Battery unit main body, 33 ... Power supply controller, 34 ... Battery, 40A ... Green LED which is a state notification means, 62 ... System | strain voltage line, 77 ... Control part, 81 ... Voltage comparison means 82... Precharge signal generation means 83... State signal generation means 84. Key position determination means 85. Conduction control means 86. Precharge circuit 95.

Claims (3)

Battery,
A capacitor electrically connected to the battery via a system voltage line;
A means for interrupting the line provided in the system voltage line;
A pre-charging circuit that electrically connects the battery and the capacitor by bypassing the means for shutting off the line in a shut-off state;
State notification means for notifying a state in which precharging from the battery side to the capacitor side is performed;
Voltage comparison means for comparing the voltage on the battery side and the voltage on the capacitor side;
Precharge signal generating means for generating a control signal for starting or stopping the precharge and outputting the control signal to the precharge circuit according to a comparison result in the voltage comparing means;
A state signal generating means for generating a state signal when pre-charging is performed and outputting the state signal to the state notification means;
And a conduction control means for controlling the line shut-off means to conduct the system voltage line when it is determined that precharging is unnecessary based on the comparison result of the voltage comparison means. vehicle. The work vehicle according to claim 1,
A power supply controller for controlling charge and discharge in the battery;
The work vehicle, wherein the voltage comparison unit, the precharge signal generation unit, the state signal generation unit, and the conduction control unit are provided in a control unit of the power supply controller. The work vehicle according to claim 2,
A key switch for activating the controller of the power supply controller;
The control unit is provided with key position determination means for determining whether the key switch is in an on position or an off position,
The state signal generating means is when the precharge is determined to be unnecessary according to the comparison result of the voltage comparing means, and when the key switch is determined to be in the ON position by the key position determining means, A state signal indicating that the charging of the capacitor is in a normal state is generated and output to the state notification means, and when it is determined that precharging is not necessary and when it is determined that the key switch is in the off position. The work vehicle is configured to stop the notification operation by the state notification means.

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