JP7744111B2 - forklift - Google Patents

Description

The present invention relates to a forklift.

When using a forklift to handle pallets and other items, 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.

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 load on the pallet to collapse. For this reason, the operator must operate the accelerator carefully to drive the forklift at a slow speed. However, for forklift beginners or operators who are not used to driving forklifts, it is difficult to perform such careful operation of the accelerator.

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 amount of accelerator operation, the traveling speed decreases when the brake is operated more, and increases when the brake is operated less. Conversely, even with the same amount of brake operation, the traveling speed increases when the accelerator is operated more, and decreases when the accelerator is operated less. However, as noted above, making precise accelerator and brake operations is difficult for forklift novices and operators who are not accustomed to driving forklifts.

There are also forklifts that are equipped with a dedicated switch to switch the driving mode to slow-speed driving mode, allowing the operator to manually press the dedicated switch to drive the forklift at slow speed. However, these forklifts have the problem of increased costs due to the additional dedicated switch.

Japanese Patent Application Laid-Open No. 2004-161471

The present invention was made in consideration of the above circumstances, and its objective 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.

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.

With this configuration, if the accelerator and brake are both pressed 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 they wish.

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.

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.

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.

The forklift
The device may further include a notification unit that visually and/or audibly notifies the operator that the set speed is limited.

The present invention provides a forklift that can be operated at slow speeds when the operator intends, without the need for an additional dedicated switch.

1 is a side view of a forklift according to an embodiment of the present invention. FIG. 2 is a block diagram of a travel control mechanism according to an embodiment of the present invention. 4 is a flowchart of a driving mode switching process of a driving controller according to an embodiment of the present invention. 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.

An embodiment of a forklift according to the present invention will be described below with reference to the accompanying drawings.

Figure 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.

The vehicle body 10 includes a body frame 11, a pair of front and rear wheels 12A and 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.

The body frame 11 forms the skeleton of the vehicle body 10, and has front wheels 12A and rear wheels 12B mounted at its bottom. The body frame 11 houses the battery BT, which serves as the power source for the forklift 1, and electric motors (in this embodiment, a travel 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 drive wheels driven by the travel motor M1, and the rear wheels 12B are steered wheels steered by the steering motor M2.

The driver's seat 13 and head guard 14 are provided on top of the vehicle frame 11. The driver's seat 13 is the operator's seat, and the head guard 14 is a protective frame that protects the operator in the driver's seat 13 from fallen luggage, etc.

The accelerator 15A is located at the front lower part of the driver's seat 13. The accelerator 15A is an accelerator pedal that can be operated by the operator of the driver's seat 13 by stepping on it with their foot. When the accelerator 15A is in the on state (pedal depressed), it accelerates the vehicle body 10 in accordance with the amount of pedal depression (accelerator opening). However, when the accelerator 15A is switched from the on state to the off state (pedal not depressed), it generates weak regenerative braking to decelerate the vehicle body 10. Note that weak regenerative braking is weaker than the regenerative braking of brake 15B, which will be described later.

Brake 15B is located below and in front of the driver's seat 13. Brake 15B is a brake pedal that can be operated by the operator of the driver's seat 13 by stepping on it with their foot. When brake 15B is in the on state (pedal is depressed), it generates regenerative braking that is stronger than the regenerative braking of accelerator 15A, thereby decelerating the vehicle body 10. However, when brake 15B is in the off state (pedal is not depressed, or the pedal depression amount is below a predetermined value, equivalent to the pedal not being depressed), it does not generate regenerative braking.

The steering wheel 16 is located 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 depending on the direction of rotation. A forward/reverse lever is provided below the steering wheel 16 for switching the vehicle body 10 between forward and reverse. When the forward/reverse lever is tilted forward and the accelerator 15A is turned on, the vehicle body 10 moves forward, and when the forward/reverse lever is tilted backward and the accelerator 15A is turned on, the vehicle body 10 moves backward.

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

The notification unit 18 is configured to visually and/or audibly notify the operator in the driver's seat 13 that the set speed, described below, is limited. In this embodiment, the notification unit 18 includes a display means (e.g., a display) and an audio means (e.g., a speaker or buzzer). The audio means may be built into the display means or may be external to the display means.

The loading and unloading device 20 comprises a mast 21, a lift bracket 22, a fork 23, a backrest 24, a tilt cylinder 25, and a lift cylinder 26.

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.

The lift bracket 22 supports the forks 23 and is configured to rise and fall along the mast 21. In this embodiment, the lift bracket 22 is attached to one end of a lift chain and rises and falls 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 attached to the top of the lift cylinder 26. The forks 23 are a pair of L-shaped arms attached to the left and right and are attached to the front of the lift bracket 22. The backrest 24 is a frame attached to the top of the lift bracket 22 to prevent cargo loaded on the forks 23 from tipping backward. When the mast 21 (inner mast) rises and falls, the lift bracket 22, forks 23, and backrest 24 also rise and fall.

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 rearward, the tilt cylinder 25 contracts and the mast 21 tilts rearward. When the tilt lever 17A is returned to the neutral position (a position that does not tilt the mast 21 forward or rearward), the tilting of the mast 21 stops.

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.

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, travel controller 34) and a travel device (travel power converter 35, travel motor M1). There are two travel power converters 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 converter 35 and one travel motor M1.

The accelerator sensor 31 detects the amount of operation (accelerator opening) of the accelerator 15A and outputs an accelerator operation signal related to that 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, reaching 100% when the amount of depression exceeds a predetermined threshold.

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

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 outputs the rotational speed (or number of rotations) of the traveling motor M1 as a speed signal, and the traveling controller 34 may calculate the traveling speed of the vehicle body 10 based on the speed signal.

The driving controller 34 is composed of, for example, a microcomputer. An accelerator operation signal, a brake operation signal, and a speed signal are input to the driving controller 34 at a predetermined cycle, and a signal related to the state of the forward/reverse lever is also input at a predetermined cycle. The driving controller 34 obtains (or calculates) the accelerator opening from the accelerator operation signal, obtains the state (on/off state) of the brake 15B from the brake operation signal, and performs processing to switch the driving mode of the vehicle body 10 (driving mode switching processing) based on the accelerator opening and the state of the brake 15B. This will be described later.

The traveling controller 34 also controls the traveling power conversion unit 35 to perform 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 brake operation signal. The target speed is calculated using the formula: Target Speed = Set Speed x 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).

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 composed of, for example, an inverter equipped with multiple 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.

The traction motor M1 is composed of 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.

When driving the traction motor M1 in powered operation, 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 and rotates the front wheels 12A. On the other hand, when driving the traction motor M1 in regenerative operation, rotational torque is transmitted from the front wheels 12A to the traction motor M1, causing the traction motor M1 to generate regenerative AC power. The traction power conversion unit 35 converts this regenerative power into DC power and supplies it to the battery BT.

Figure 3 shows a flowchart of the driving mode switching process performed by the driving controller 34.

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). Driving modes include "normal mode," which corresponds to the "first mode" of the present invention, "set mode," which corresponds to the "second mode" of the present invention, and "slow speed mode," which corresponds to the "third mode" of the present invention. Since the driving mode is set to "normal mode" at the start of the process, the driving controller 34 determines that it is "normal mode."

When the driving controller 34 determines that the vehicle is in "normal mode," it sets the set speed to the first set speed (in this embodiment, the first set speed = 16 km/h) (S2). Since the set speed is not limited in "normal mode," the driving controller 34 turns off notifications from the notification unit 18.

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 "set mode" (S4) and proceeds to processing in 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 processing in step S5 without changing the driving mode.

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 [%]. Because 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 returns to the processing of step S1. The control cycle for the driving mode switching process is, for example, 2 [ms].

If the driving controller 34 determines in step S1 that the driving mode is "set mode," it sets the set speed to the second set speed (in this embodiment, the second set speed = 1 km/h) (S6). Because the set speed is limited in "set mode," the driving controller 34 turns on notifications from the notification unit 18 to notify the operator that the set speed is limited.

Next, the driving 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 driving controller 34 sets the driving mode to "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 driving controller 34 proceeds to the processing of step S5 without changing the driving mode.

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 S8, the set speed is the second set speed (= 1 [km/h]). After calculating the target speed, the driving controller 34 returns to the processing of step S1.

If the driving controller 34 determines in step S1 that the driving mode is "slow speed mode," it sets the set speed to the third set speed (in this embodiment, the third set speed = 1 km/h) (S9). Because the set speed is limited in "slow speed mode," the driving controller 34 turns on notifications from the notification unit 18 to notify the operator that the set speed is limited.

Next, the driving 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 driving controller 34 sets the driving mode to "normal mode" (S11) and proceeds to the processing of step S5.

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 "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.

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 [%]. 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 driving controller 34 again proceeds to the processing of step S1.

Figure 4 shows the change in target speed and travel speed over time when switching travel modes. Note that in Figure 4, the forward/reverse lever is tilted forward (i.e., the forklift 1 is moving forward).

In 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 main body 10 based on the speed signal) is also 16 km/h.

At t1, when the operator steps on the brake 15B, both the accelerator 15A and the brake 15B are turned on, and the driving controller 34 switches the driving mode from "normal mode" to "set mode." The driving 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 x 100%).

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

At t2, when the brake 15B is turned off, the driving controller 34 applies weak regenerative braking to decelerate the vehicle body 10. In other words, in speed control, the driving controller 34 reduces the amount of change in driving speed (deceleration amount) to a value less than when the brake 15B is turned on.

At t3, when the traveling speed of the vehicle body 10 reaches the target speed, the traveling controller 34 performs speed control to maintain the traveling 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 traveling controller 34 changes the target speed from 1 km/h to 0.5 km/h (= 1 km/h x 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 t5, when the accelerator opening changes from 50% to 0%, both the accelerator 15A and the brake 15B are turned off, and the driving controller 34 switches the driving mode from "set mode" to "slow speed mode." The driving controller 34 also switches the set speed from the second set speed to the third set speed. However, in this embodiment, both are 1 km/h, so the set speed remains the same and the target speed is changed from 1 km/h to 0 (= 1 km/h x 0%).

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

At t8, when the operator steps on the brake 15B, the accelerator 15A is in the off state and the brake 15B is in the on state, so the driving controller 34 switches the driving mode from "slow speed mode" to "normal mode." The driving controller 34 also switches the set speed from the third set speed of 1 km/h to the first set speed of 16 km/h, but because the accelerator opening is 0% the target speed remains 0 (= 16 km/h x 0%).

In conclusion, with the forklift 1 according to this embodiment, when the accelerator 15A and brake 15B are simultaneously turned on, the set speed is limited to 1 km/h 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.

With the forklift 1 according to this embodiment, precise accelerator operation is not necessary. 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, with the forklift 1 according to this embodiment, as described above, the set speed is limited to 1 km/h and the target speed is reduced, making it possible to travel at a slow speed of 1 km/h even with an accelerator opening of 100% (see, for example, t3-t4 in Figure 4). In other words, with the forklift 1 according to this embodiment, even forklift novices or operators who are not accustomed to driving forklifts can easily travel at a slow speed.

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

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

The above describes an embodiment of the forklift according to the present invention, but the present invention is not limited to the above embodiment.

The forklift according to the present invention comprises a vehicle body equipped with a loading and unloading device, a travel device that drives the vehicle body, an accelerator and brake that can be operated by an operator, and a travel control unit that controls the travel device to bring the travel speed of the vehicle body closer to a predetermined target speed. The travel control unit calculates the target speed by multiplying a predetermined set speed by the accelerator opening, and can be configured as appropriate so long as it limits the set speed and reduces the target speed when the accelerator and brake are simultaneously turned on.

In the above embodiment, the second set speed in "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 less than the first set speed in "normal mode." However, in order to eliminate the need for precise accelerator operation, it is preferable that the second set speed be no more than 1/10 of the first set speed. Similarly, the value of the third set speed in "slow speed mode" can be changed as appropriate as long as it is greater than 0 and less than the first set speed in "normal mode." However, in order to eliminate the need for precise accelerator operation, it is preferable that the third set speed be no more than 1/10 of the first set speed.

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

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.

In the above embodiment, the notification unit 18 is configured to include a display means (e.g., a display) and an audio means (e.g., a speaker or buzzer), but it may also be configured to include only one of these.

In the above embodiment, a counterbalance-type battery forklift is used as an example, but the forklift according to the present invention may also be a different type of battery forklift (e.g., a reach type), an engine forklift other than a battery forklift, or a hybrid forklift equipped with a battery and an engine.

DESCRIPTION OF SYMBOLS 1 Forklift 10 Vehicle body 11 Body frame 12A Front wheels 12B Rear wheels 13 Driver's seat 14 Head guard 15A Accelerator 15B Brake 16 Handle 17A Tilt lever 17B Lift lever 18 Notification unit 20 Load handling device 21 Mast 22 Lift bracket 23 Fork 24 Backrest 25 Tilt cylinder 26 Lift cylinder 30 Travel control mechanism 31 Accelerator sensor 32 Brake sensor 33 Vehicle speed sensor 34 Travel controller 35 Travel power conversion unit

Claims (4)

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: The traveling control unit
2. The forklift according to claim 1 , wherein the second set speed and the third set speed are set to the same value. 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,
2. The forklift according to claim 1 , wherein, in the third mode, the traveling mode is switched to the first mode when the accelerator is released and the brake is applied simultaneously. 2. The forklift according to claim 1, further comprising a notification unit that visually and/or audibly notifies the operator that the set speed is limited.