forklift

Abstract

To provide a forklift capable of traveling at a very low speed when an operator intends, without requiring any additional exclusive switch.SOLUTION: A forklift 1 includes: a vehicle body 10 provided with a loading device 20; an accelerator 15A and a brake 15B configured to be operable by an operator; and a travel control unit for controlling a travel speed to approach a predetermined target speed. The travel control unit: calculates a target speed from a product of a predetermined set speed and an accelerator opening of the accelerator 15A; and when an on-operation of the accelerator 15A and an on-operation of the brake 15B are simultaneously performed, reduces the target speed by limiting the set speed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a forklift truck. [Background technology]

[0002] When using a forklift to handle pallets or other materials, the forklift operator must align the tips of the forks with the center of the holes in the pallet, operate the accelerator to move the forklift forward, and insert the forks all the way into the holes in the pallet.

[0003] When inserting the forks deep into the holes in a pallet, if the forklift is traveling too fast, the forks may collide with the pallet due to excessive momentum, causing the pallet to collapse. For this reason, the operator must operate the accelerator carefully to drive the forklift at a slow speed. However, forklift beginners and operators who are not used to driving forklifts, it is difficult to perform such careful accelerator operation.

[0004] For example, Patent Document 1 describes a forklift that can adjust its traveling speed by simultaneously operating the accelerator and brake. With the forklift described in Patent Document 1, even with the same accelerator operation amount, the traveling speed decreases when the brake operation amount is large, and increases when the brake operation amount is small. Conversely, even with the same brake operation amount, the traveling speed increases when the accelerator operation amount is large, and decreases when the accelerator operation amount is small. However, as described above, precise accelerator and brake operation is difficult for forklift novices and operators who are not accustomed to driving forklifts.

[0005] There are also forklifts that are equipped with a dedicated switch to switch the driving mode to slow speed driving mode, and the operator of such forklifts can drive the forklift at slow speed by manually pressing the dedicated switch. However, the additional dedicated switch on such forklifts increases costs. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-161471 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a forklift that can be made to travel at a slow speed when the operator intends, without requiring an additional dedicated switch. [Means for solving the problem]

[0008] In order to solve the above problems, the forklift according to the present invention comprises: a vehicle body provided with a loading device; a traveling device that causes the vehicle body to travel; an accelerator and a brake configured to be operable by an operator; a travel control unit that controls the travel device so that the travel speed of the vehicle body approaches a predetermined target speed; A forklift truck comprising: The traveling control unit The target speed is calculated by multiplying a predetermined set speed by the accelerator opening degree of the accelerator, and when the accelerator is turned on and the brake is turned on simultaneously, the set speed is limited to reduce the target speed.

[0009] In this configuration, when the accelerator and brake are turned on simultaneously, the set speed is limited and the target speed is reduced, so no additional dedicated switch is required and the operator can travel at a slow speed when he or she wishes.

[0010] In the forklift, The traveling control unit setting the driving mode of the vehicle body to a first mode, a second mode, or a third mode; In the first mode, the target speed is calculated by multiplying a predetermined first set speed by the accelerator opening degree, In the second mode, the target speed is calculated by multiplying a second set speed, which is smaller than the first set speed, by the accelerator opening degree; In the third mode, the target speed is calculated by multiplying a third set speed, which is smaller than the first set speed, by the accelerator opening degree; In the first mode, when the accelerator and the brake are simultaneously operated, the driving mode is switched to the second mode; In the second mode, the driving mode may be switched to the third mode when the accelerator and brake are simultaneously released.

[0011] In the forklift, The traveling control unit The second set speed and the third set speed may be configured to be set to the same value.

[0012] In the forklift, The traveling control unit In the third mode, when the accelerator pedal is turned on and the brake pedal is turned on simultaneously, the driving mode is switched to the second mode, In the third mode, the driving mode may be switched to the first mode when the accelerator is released and the brake is applied simultaneously.

[0013] The forklift The device may further include a notification unit that visually and / or audibly notifies the operator that the set speed is limited. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a forklift that can be made to travel at a slow speed when the operator intends, without requiring an additional dedicated switch. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a side view of a forklift according to an embodiment of the present invention. [Figure 2] FIG. 2 is a block diagram of a travel control mechanism according to an embodiment of the present invention. [Figure 3] 4 is a flowchart of a driving mode switching process of a driving controller according to an embodiment of the present invention. [Figure 4] FIG. 4 is a diagram showing the relationship between the target speed and the traveling speed of the forklift according to the embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a forklift according to the present invention will be described with reference to the accompanying drawings.

[0017] 1 shows a side view of a forklift 1 according to one embodiment of the present invention. The forklift 1 is a counterbalance type battery forklift, and includes a vehicle body 10 and a cargo handling device 20.

[0018] The vehicle body 10 includes a body frame 11, a pair of front wheels 12A and rear wheels 12B, a driver's seat 13, a head guard 14, an accelerator 15A and a brake 15B, a steering wheel 16, loading levers (tilt lever 17A and lift lever 17B), and a notification unit 18.

[0019] The body frame 11 forms the skeleton of the vehicle body 10, and has front wheels 12A and rear wheels 12B provided at its bottom. The body frame 11 houses a battery BT, which is the power source of the forklift 1, and electric motors (in this embodiment, a traveling motor M1, a steering motor M2, and a cargo handling motor M3) that are driven by the power of the battery BT. In the forklift 1, the front wheels 12A are driving wheels driven by the traveling motor M1, and the rear wheels 12B are steering wheels steered by the steering motor M2.

[0020] The driver's seat 13 and head guard 14 are provided on the upper part of the body frame 11. The driver's seat 13 is the seat of the operator, and the head guard 14 is a protective frame that protects the operator in the driver's seat 13 from dropped luggage and the like.

[0021] The accelerator 15A is provided at the front lower part of the driver's seat 13. The accelerator 15A is an accelerator pedal configured to be operable by an operator in the driver's seat 13 by stepping on it with his / her foot. When the accelerator 15A is in an on state (pedal depressed), it accelerates the traveling of the vehicle body 10 in accordance with the amount of depression of the pedal (accelerator opening), and when it switches from the on state to an off state (pedal not depressed), it generates weak regenerative braking to decelerate the vehicle body 10. Note that the weak regenerative braking is weaker than the regenerative braking of brake 15B, which will be described later.

[0022] Brake 15B is provided in a front lower portion of driver's seat 13. Brake 15B is a brake pedal configured to be operable by an operator in driver's seat 13 stepping on it with their foot. When brake 15B is in an on state (pedal is depressed), it generates regenerative braking stronger than that of accelerator 15A, thereby decelerating vehicle body 10, but when brake 15B is in an off state (pedal is not depressed, or the amount of pedal depression is equal to or less than a predetermined value and is equivalent to not depressing the pedal), it does not generate regenerative braking.

[0023] The steering wheel 16 is provided in front of the driver's seat 13. The steering wheel 16 is connected to the rear wheels 12B via a steering control mechanism including a steering motor M2. By rotating the steering wheel 16, the operator can change the direction of the rear wheels 12B according to the direction of rotation. A forward / reverse lever is provided below the steering wheel 16 for switching the traveling of the vehicle body 10 between forward and reverse. When the accelerator 15A is turned on with the forward / reverse lever tilted forward, the vehicle body 10 moves forward, and when the accelerator 15A is turned on with the forward / reverse lever tilted backward, the vehicle body 10 moves backward.

[0024] The cargo handling levers (tilt lever 17A and lift lever 17B) are provided in front of the driver's seat 13. The cargo handling levers are connected to the cargo handling device 20 via a cargo handling control mechanism including a cargo handling motor M3 and a hydraulic device (not shown). The operator can operate the cargo handling device 20 by manipulating the cargo handling levers.

[0025] The notification unit 18 is configured to visually and / or audibly notify the operator in the driver's seat 13 that the set speed, which will be described later, is limited. The notification unit 18 of this embodiment includes a display means (e.g., a display) and an audio means (e.g., a speaker or a buzzer). The audio means may be built into the display means or may be externally attached to the display means.

[0026] The cargo handling device 20 includes a mast 21, a lift bracket 22, a fork 23, a backrest 24, a tilt cylinder 25, and a lift cylinder 26.

[0027] The mast 21 is provided at the front of the vehicle body 10 and is configured to raise and lower the forks 23. In this embodiment, the mast 21 comprises an outer mast and an inner mast. The outer mast comprises a pair of left and right guide rails extending vertically, and a cross beam connecting the upper ends of the guide rails. The inner mast is provided inside the guide rails of the outer mast and rises and falls along the guide rails of the outer mast.

[0028] The lift bracket 22 is configured to support the forks 23 and to move up and down along the mast 21. In this embodiment, the lift bracket 22 is attached to one end of a lift chain and moves up and down along the inner mast while suspended from the lift chain. The other end of the lift chain is attached to the lower part of the outer mast via a chain wheel provided on the upper part of the lift cylinder 26. The forks 23 are a pair of L-shaped arms on the left and right and are provided on the front of the lift bracket 22. The backrest 24 is a frame that prevents cargo loaded on the forks 23 from tipping backward and is provided on the upper part of the lift bracket 22. When the mast 21 (inner mast) moves up and down, the lift bracket 22, forks 23, and backrest 24 also move up and down.

[0029] The tilt cylinder 25 is a hydraulic cylinder for tilting the mast 21 in the forward and backward directions. In this embodiment, when the tilt lever 17A is tilted forward, the tilt cylinder 25 extends and the mast 21 tilts forward, and when the tilt lever 17A is tilted backward, the tilt cylinder 25 contracts and the mast 21 tilts backward. When the tilt lever 17A is returned to the neutral position (a position that does not tilt the mast 21 forward or backward), the tilting of the mast 21 stops.

[0030] The lift cylinder 26 is a hydraulic cylinder for raising and lowering the mast 21. In this embodiment, when the lift lever 17B is tilted forward, the lift cylinder 26 contracts and the inner mast lowers, and when the lift lever 17B is tilted backward, the lift cylinder 26 extends and the inner mast rises. When the lift lever 17B is returned to the neutral position (a position where the inner mast is neither tilted forward nor backward), the raising and lowering of the inner mast stops.

[0031] As shown in Fig. 2, the forklift 1 is equipped with a travel control mechanism 30 including a travel motor M1. The travel control mechanism 30 includes a travel control unit (accelerator sensor 31, brake sensor 32, vehicle speed sensor 33, and travel controller 34) and a travel device (travel power conversion unit 35, travel motor M1). There are two travel power conversion units 35 and two travel motors M1, one for the left front wheel 12A and one for the right front wheel 12A, but because they have the same configuration, only one of each is shown in the figure. Note that depending on the model of forklift 1, there may be only one travel power conversion unit 35 and one travel motor M1.

[0032] The accelerator sensor 31 detects the amount of operation (accelerator opening) of the accelerator 15A, and outputs an accelerator operation signal related to the amount of operation (accelerator opening) to the driving controller 34. The accelerator opening is 0[%] when the accelerator 15A is in the OFF state, and increases in proportion to the amount of depression of the accelerator 15A when the accelerator 15A is in the ON state, and becomes 100[%] when the amount of depression exceeds a predetermined threshold.

[0033] The brake sensor 32 detects the state (on state / off state) of the brake 15B and outputs a brake operation signal relating to the state to the driving controller 34. The brake sensor 32 is originally provided in order to turn on the brake lamps provided on the vehicle body 10 (and turn them off when the brakes are off).

[0034] The vehicle speed sensor 33 detects the traveling speed of the vehicle body 10 and outputs a speed signal related to the traveling speed to the traveling controller 34. The vehicle speed sensor 33 may output the rotation speed (or number of rotations) of the traveling motor M1 as the speed signal, and the traveling controller 34 may calculate the traveling speed of the vehicle body 10 based on the speed signal.

[0035] The traveling controller 34 is configured by, for example, a microcomputer. An accelerator operation signal, a brake operation signal, and a speed signal are input to the traveling controller 34 at a predetermined cycle, and a signal relating to the state of the forward / reverse lever is also input at a predetermined cycle. The traveling controller 34 acquires (or calculates) the accelerator opening from the accelerator operation signal, acquires the state (on state / off state) of the brake 15B from the brake operation signal, and executes a process (traveling mode switching process) to switch the traveling mode of the vehicle body 10 based on the accelerator opening and the state of the brake 15B. This will be described later.

[0036] Furthermore, the traveling controller 34 controls the traveling power conversion unit 35 by executing speed control to bring the traveling speed of the vehicle body 10 closer to a predetermined target speed. Specifically, the traveling controller 34 acquires (or calculates) the traveling speed of the vehicle body 10 based on the speed signal, and calculates the target speed based on the accelerator operation signal and / or the brake operation signal. The target speed is calculated using the formula: Target speed = Set speed × Accelerator opening [%]. The set speed is set by the traveling controller 34 for each traveling mode, which will be described later. The traveling controller 34 performs, for example, PI control or PID control as speed control to bring the traveling speed closer to the predetermined target speed, and outputs a control signal to the traveling power conversion unit 35 (for example, a drive signal for a switching element of the traveling power conversion unit 35).

[0037] The traction motor M1 is connected to one side of the traction power conversion unit 35, and the battery BT is connected to the other side. The traction power conversion unit 35 is configured, for example, by an inverter including a plurality of switching elements (e.g., transistors) that are turned on and off under the control of the traction controller 34, and drives the traction motor M1 (power running or regenerative running) under the control of the traction controller 34.

[0038] The traction motor M1 is configured as a DC motor or an AC motor and is connected to the front wheels 12A. In this embodiment, an AC motor is used as the traction motor M1. For example, if a three-phase induction motor is used as the traction motor M1, a three-phase bridge inverter can be used as the traction power conversion unit 35.

[0039] When the traction motor M1 is operated in power running, the traction power conversion unit 35 converts the DC power of the battery BT into AC power and supplies it to the traction motor M1. This drives the traction motor M1 to rotate the front wheels 12A. On the other hand, when the traction motor M1 is operated in regenerative running, rotational torque is transmitted from the front wheels 12A to the traction motor M1, and the traction motor M1 generates regenerative AC power, which the traction power conversion unit 35 converts into DC power and supplies to the battery BT.

[0040] FIG. 3 shows a flowchart of the driving mode switching process performed by the driving controller 34.

[0041] When the driving controller 34 is powered on (power supply voltage is supplied from the battery BT), the driving controller 34 starts the driving mode switching process. After starting the driving mode switching process, the driving controller 34 determines the driving mode (S1). The driving modes include a "normal mode" which corresponds to the "first mode" of the present invention, a "set mode" which corresponds to the "second mode" of the present invention, and a "slow speed mode" which corresponds to the "third mode" of the present invention. Since the driving mode at the start of the process is set to the "normal mode," the driving controller 34 determines that the mode is the "normal mode."

[0042] The traveling controller 34, which has determined that the mode is "normal mode," sets the set speed to the first set speed (in this embodiment, the first set speed = 16 [km / h]) (S2). In "normal mode," the set speed is not limited, so the traveling controller 34 turns off notifications by the notification unit 18.

[0043] Next, the driving controller 34 determines whether the accelerator 15A is on and the brake 15B is on (S3). If both the accelerator 15A and the brake 15B are on (Yes in S3), the driving controller 34 sets the driving mode to the "set mode" (S4) and proceeds to the processing of step S5. If at least one of the accelerator 15A and the brake 15B is off (No in S3), the driving controller 34 proceeds to the processing of step S5 without changing the driving mode.

[0044] In step S5, the driving controller 34 calculates the target speed. The target speed is calculated using the formula: target speed = set speed x accelerator opening [%]. Since the set speed was not changed in step S4, the set speed is the first set speed (= 16 [km / h]). After calculating the target speed in step S5, the driving controller 34 again proceeds to the processing of step S1. The control cycle of the driving mode switching processing is, for example, 2 [ms].

[0045] If the traveling controller 34 determines in the processing of step S1 that the traveling mode is "set mode," it sets the set speed to a second set speed (in this embodiment, the second set speed = 1 [km / h]) (S6). Since the set speed is limited in "set mode," the traveling controller 34 turns on notifications by the notification unit 18 to notify the operator that the set speed is limited.

[0046] Next, the traveling controller 34 determines whether the accelerator 15A is in the OFF state and the brake 15B is in the OFF state (S7). If both the accelerator 15A and the brake 15B are in the OFF state (Yes in S7), the traveling controller 34 sets the traveling mode to the "low speed mode" (S8) and proceeds to the processing of step S5. If at least one of the accelerator 15A and the brake 15B is in the ON state (No in S7), the traveling controller 34 proceeds to the processing of step S5 without changing the traveling mode.

[0047] In step S5, the traveling controller 34 calculates the target speed. The target speed is calculated using the formula: Target speed = Set speed x Accelerator opening [%]. Since the set speed was not changed in step S8, the set speed is the second set speed (= 1 [km / h]). After calculating the target speed, the traveling controller 34 again proceeds to the processing of step S1.

[0048] If the traveling controller 34 determines in the processing of step S1 that the traveling mode is "slow speed mode," it sets the set speed to a third set speed (in this embodiment, the third set speed = 1 [km / h]) (S9). Since the set speed is limited in "slow speed mode," the traveling controller 34 turns on notifications by the notification unit 18 to notify the operator that the set speed is limited.

[0049] Next, the traveling controller 34 determines whether the accelerator 15A is in the OFF state and the brake 15B is in the ON state (S10). If the accelerator 15A is in the OFF state and the brake 15B is in the ON state (Yes in S10), the traveling controller 34 sets the traveling mode to the "normal mode" (S11) and proceeds to the processing of step S5.

[0050] If the accelerator 15A is on or the brake 15B is off (No in S10), the driving controller 34 determines whether the accelerator 15A is on and the brake 15B is on (S12). If both the accelerator 15A and the brake 15B are on (Yes in S12), the driving controller 34 sets the driving mode to the "set mode" (S13) and proceeds to the processing of step S5. If at least one of the accelerator 15A and the brake 15B is off (No in S12), the driving controller 34 proceeds to the processing of step S5 without changing the driving mode.

[0051] In step S5, the traveling controller 34 calculates the target speed. The target speed is calculated using the formula: target speed = set speed x accelerator opening [%]. Because the set speed was not changed in steps S11 and S13, the set speed is the third set speed (= 1 [km / h]). After calculating the target speed, the traveling controller 34 again proceeds to the processing of step S1.

[0052] Figure 4 shows the time changes in the target speed and the traveling speed when switching the traveling mode. In Figure 4, the forward / reverse lever is tilted forward (i.e., the forklift 1 is moving forward).

[0053] During the period before t1, the driving mode is "normal mode," the accelerator opening is 100[%], and the brake is off. The target speed calculated by the driving controller 34 is 16[km / h] (=16[km / h]×100[%]), and the actual driving speed (the driving speed calculated by the vehicle body 10 based on the speed signal) is also 16[km / h].

[0054] At t1, when the operator depresses the brake 15B, both the accelerator 15A and the brake 15B are turned on, and the traveling controller 34 switches the traveling mode from the "normal mode" to the "set mode." The traveling controller 34 also switches the set speed from the first set speed of 16 [km / h] to the second set speed of 1 [km / h], and changes the target speed from 16 [km / h] to 1 [km / h] (= 1 [km / h] × 100 [%]).

[0055] During the period after t1 and before t2, the brake 15B is in the ON state, and therefore the traveling controller 34 generates strong regenerative braking to decelerate the vehicle body 10. That is, in speed control that brings the traveling speed of the vehicle body 10 closer to the target speed (1 km / h), the traveling controller 34 increases the amount of change in the traveling speed (deceleration amount) compared to the value when the brake 15B is in the OFF state. Note that the amount of change in the traveling speed (deceleration amount) can be adjusted by, for example, adjusting the control gain of PI control or PID control.

[0056] At t2, when the brake 15B is turned off, the traveling controller 34 generates weak regenerative braking to decelerate the vehicle body 10. That is, in the speed control, the traveling controller 34 makes the amount of change in the traveling speed (deceleration amount) smaller than the value when the brake 15B is in the on state.

[0057] At t3, when the running speed of the vehicle body 10 reaches the target speed, the running controller 34 performs speed control to maintain the running speed of the vehicle body 10 at the target speed (1 [km / h]). At t4, when the accelerator opening changes from 100 [%] to 50 [%], the running controller 34 changes the target speed from 1 [km / h] to 0.5 [km / h] (= 1 [km / h] × 50 [%]) and performs speed control to bring the running speed of the vehicle body 10 closer to the target speed of 0.5 [km / h].

[0058] At t5, when the accelerator opening changes from 50% to 0%, both the accelerator 15A and the brake 15B are turned off, so the traveling controller 34 switches the traveling mode from the "set mode" to the "slow speed mode." The traveling controller 34 also switches the set speed from the second set speed to the third set speed, but in this embodiment, both are 1 km / h, so the target speed is changed from 1 km / h to 0 (= 1 km / h × 0%]) without changing the set speed.

[0059] At t6, when the accelerator opening changes from 0[%] to 50[%], the traveling controller 34 changes the target speed from 0 to 0.5[km / h] (=1[km / h]×50[%]) and performs speed control to bring the traveling speed of the vehicle body 10 closer to the target speed of 0.5[km / h]. At t7, when the accelerator opening changes from 50[%] to 0[%], the traveling controller 34 changes the target speed from 0.5[km / h] to 0 (=1[km / h]×0[%]) and performs speed control to bring the traveling speed of the vehicle body 10 closer to the target speed of 0.

[0060] At t8, when the operator depresses the brake 15B, the accelerator 15A is in the OFF state and the brake 15B is in the ON state, so the traveling controller 34 switches the traveling mode from the "slow speed mode" to the "normal mode." The traveling controller 34 also switches the set speed from 1 [km / h], which is the third set speed, to 16 [km / h], which is the first set speed, but because the accelerator opening is 0 [%], the target speed remains 0 (= 16 [km / h] × 0 [%]).

[0061] In the end, in the forklift 1 according to this embodiment, when the accelerator 15A and the brake 15B are turned on simultaneously, the set speed is limited to 1 km / h and the target speed is reduced, so that an additional dedicated switch is not required and the operator can travel at a slow speed when he or she wishes.

[0062] The forklift 1 according to this embodiment eliminates the need for precise accelerator operation. For example, in the case of a conventional forklift with a fixed set speed of 16 km / h, to travel at a slow speed of 1 km / h, the accelerator opening must be set to 6.25% according to the formula: target speed = set speed x accelerator opening [%]. In contrast, the forklift 1 according to this embodiment limits the set speed to 1 km / h as described above, thereby lowering the target speed. This makes it possible to travel at a slow speed of 1 km / h even with an accelerator opening of 100% (see, for example, t3 to t4 in FIG. 4). In other words, with the forklift 1 according to this embodiment, even a forklift novice or an operator who is not accustomed to driving a forklift can easily travel at a slow speed.

[0063] In the forklift 1 according to this embodiment, the driving mode is switched to the "normal mode" under the condition that the accelerator 15A is in the off state and the brake 15B is in the on state in the "slow speed mode." This prevents the forklift 1 from accelerating the moment it switches to the "normal mode," thereby improving safety.

[0064] Furthermore, in the forklift 1 according to this embodiment, switching from the "normal mode" to the "slow speed mode" via the "set mode" can be avoided, thereby preventing the set speed and target speed from frequently switching over a short period of time. If frequent switching over of the set speed and target speed over a short period of time is acceptable, the "set mode" may be eliminated and switching over between the "normal mode" and the "slow speed mode" can be performed. In this case, for example, the forklift 1 can be configured so that switching from the "normal mode" to the "slow speed mode" occurs when the accelerator 15A and the brake 15B are simultaneously turned on, and switching from the "slow speed mode" to the "normal mode" occurs when the accelerator 15A is turned off and the brake 15B is turned on.

[0065] Although the embodiment of the forklift according to the present invention has been described above, the present invention is not limited to the above embodiment.

[0066] The forklift according to the present invention is a forklift comprising a vehicle body provided with a loading device, a traveling device for driving the vehicle body, an accelerator and a brake operable by an operator, and a traveling control unit for controlling the traveling device so as to bring the traveling speed of the vehicle body closer to a predetermined target speed, and the traveling control unit calculates the target speed by multiplying the predetermined set speed by the accelerator opening degree, and the configuration can be modified as appropriate as long as it limits the set speed and reduces the target speed when the accelerator and brake are turned on simultaneously.

[0067] In the above embodiment, the second set speed in the "set mode" is set to 1 [km / h], but the value of the second set speed can be changed as appropriate as long as it is greater than 0 and smaller than the first set speed in the "normal mode." However, in order to eliminate the need for delicate accelerator operation, it is preferable that the second set speed be equal to or less than 1 / 10 of the first set speed. Similarly, the value of the third set speed in the "very slow speed mode" can be changed as appropriate as long as it is greater than 0 and smaller than the first set speed in the "normal mode." However, in order to eliminate the need for delicate accelerator operation, it is preferable that the third set speed be equal to or less than 1 / 10 of the first set speed.

[0068] The second and third set speeds may be the same or different values. From a safety standpoint, it is preferable to set the second and third set speeds to the same value so that the operator can experience the same operational feeling in both the "set mode" and the "slow speed mode."

[0069] In the above embodiment, the accelerator 15A is an accelerator pedal configured to be operated by the operator's foot, and the brake 15B is a brake pedal configured to be operated by the operator's foot, but at least one of them may be a lever operated by hand. If the accelerator 15A is an accelerator lever, the amount of operation of the accelerator lever corresponds to the "accelerator opening" of the present invention. However, by configuring both the accelerator 15A and the brake 15B to be operated by the foot (pedal configuration) as in the above embodiment, the operator can easily operate the accelerator 15A and the brake 15B without visually checking them.

[0070] In the above embodiment, the notification unit 18 is configured to include a display means (for example, a display) and an audio means (for example, a speaker or a buzzer), but it may be configured to include only one of them.

[0071] In the above embodiment, a counterbalance type battery forklift is used as an example, but the forklift according to the present invention may be a battery forklift of another type (for example, a reach type), an engine forklift other than a battery forklift, or a hybrid forklift equipped with a battery and an engine. [Explanation of symbols]

[0072] 1 forklift 10 Vehicle body 11 Body frame 12A front wheel 12B rear wheel 13 Driver's seat 14 Head Guard 15A Accelerator 15B Brake 16 Handle 17A Tilt Lever 17B Lift lever 18 Notification Department 20 Cargo handling equipment 21 Mast 22 Lift bracket 23 Fork 24 Backrest 25 Tilt cylinder 26 Lift cylinder 30 Driving control mechanism 31 Accelerator sensor 32 Brake sensor 33 Vehicle speed sensor 34 Driving controller 35 Power conversion unit for driving

Claims

1. a vehicle body provided with a loading device; a traveling device that causes the vehicle body to travel; an accelerator and a brake configured to be operable by an operator; a travel control unit that controls the travel device so that the travel speed of the vehicle body approaches a predetermined target speed; A forklift truck comprising: The traveling control unit The target speed is calculated by multiplying a predetermined set speed by an accelerator opening degree of the accelerator, and when an ON operation of the accelerator and an ON operation of the brake are performed simultaneously, the set speed is limited to reduce the target speed; setting the driving mode of the vehicle body to a first mode, a second mode, or a third mode; In the first mode, the target speed is calculated by multiplying a predetermined first set speed by the accelerator opening degree, In the second mode, the target speed is calculated by multiplying a second set speed, which is smaller than the first set speed, by the accelerator opening degree; In the third mode, the target speed is calculated by multiplying a third set speed, which is smaller than the first set speed, by the accelerator opening degree; In the first mode, when the accelerator and the brake are simultaneously operated, the driving mode is switched to the second mode; In the second mode, when the accelerator and brake are simultaneously released, the driving mode is switched to the third mode. A forklift characterized by:

2. The traveling control unit The second set speed and the third set speed are set to the same value.

2. The forklift according to claim 1.

3. The traveling control unit In the third mode, when the accelerator pedal is turned on and the brake pedal is turned on simultaneously, the driving mode is switched to the second mode, In the third mode, when the accelerator is released and the brake is applied simultaneously, the driving mode is switched to the first mode.

2. The forklift according to claim 1.

4. The apparatus further includes a notification unit that visually and / or audibly notifies the operator that the set speed is limited.

2. The forklift according to claim 1.

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