JPH09117014A - Speed limiter for battery forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a plurality of kinds of limited speed without requiring any modification for limit speed by an operator by extracting a vehicle speed being set through a Hi/Low switch, comparing the extracted speed with a vehicle speed detected by a vehicle speed sensor and then controlling a drive motor not to exceed the speed limit. SOLUTION: A set vehicle speed extracting means 2b for a controller 2 extracts a set vehicle speed corresponding to the decision results of a vehicle speed setting Hi/Low decision means 2a from a memory 4, and a vehicle speed- current function extracting means 2c extracts a vehicle speed-current function for a set vehicle speed extracted by the set vehicle speed extracting means 2b from the memory 4. A current command value operating means 2d then determined a current command value from the vehicle speed detected by a vehicle speed sensor 5 according to a vehicle speed-current function extracted by the vehicle speed-current function extracting means 2c. Based on the current command value, a power conversion circuit 2f produces a current which is then fed to a drive motor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed limiter for a battery-powered forklift.

[0002]

2. Description of the Related Art In a battery-powered forklift, its power source is a battery-driven motor, and the drive wheels are moved by this motor to travel. In this case, a speed limit function is added to ensure proper use in the factory. For example, the changeover switch in the driver's seat can be used to switch between "no speed limit / speed limit". Therefore, in the case of "limiting the speed", the power conversion circuit in the preceding stage is controlled to limit the output of the drive motor.

[0003]

However, even in the case of selecting the "limit speed" of the changeover switch in the above-mentioned system, the speed limit can be freely changed by the operator. However, the effect of speed limitation is not substantially obtained. Even if the speed limit is fixed and adjustment by the operator is impossible, there are always two types of indoor speeds, indoor and outdoor, in factories where forklifts are generally used. I can't.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a speed limiter for a battery-operated forklift that can obtain a plurality of kinds of speed limits without changing the speed limit by an operator.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention extracts a Hi / Low switch for switching a speed limit value and a vehicle speed set to be adjustable by the input of the Hi / Low switch. And a travel controller that controls the drive motor so as not to exceed the speed limit in comparison with the vehicle speed by the vehicle speed sensor.

Since the Hi / Low switch has two kinds of speed limits, indoor and outdoor speeds can be obtained.
If the operator cannot adjust the vehicle speed, the speed limit from the beginning can be maintained. In addition, switch "H
By including it in “i”, the case of “no speed limit” can be incorporated.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Here, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a simplified external view of a battery-powered forklift, and a Hi / Low switch 1 for speed limitation is provided in front of a driver's seat. The Hi / Low switch 1 is connected to a traveling controller 2 having a function of setting a vehicle speed limit value, and the drive of the drive wheels 3 is controlled by a command from the traveling controller 2. Further, in order to limit the speed, it is necessary to detect the vehicle speed, and although omitted in FIG. 1, a vehicle speed sensor is connected to the travel controller.

FIG. 2 is a view mainly showing the traveling controller. Hi / Lo is provided on the input side of the traveling controller 2.
A w-switch 1, an external memory 4 and a vehicle speed sensor 5 are present, and a drive motor 6 is present on the output side. Hi / Low
The switch 1 outputs one of two types of Hi / Low switches. The vehicle speed setting Hi / Lo determination means 2a in the traveling controller 2 receives the signal of either Hi / Lo from the Hi / Low switch 1 and determines it, and then the set vehicle speed extraction means 2b outputs H.
The set vehicle speed corresponding to the i / Lo determination result is extracted from the memory 4. Further, the vehicle speed-current function extracting means 2c extracts the vehicle speed-current function from the memory 4 from the obtained set vehicle speed. Therefore, in the memory 4, Hi, Lo of the switch 1
The vehicle speed corresponding to w is stored, and the vehicle speed-current function is stored. For the vehicle speed-current function extracted by the vehicle speed-current function extraction means 2c, a current command value is obtained from the vehicle speed obtained from the vehicle speed sensor 5 by the current command value calculation means 2d and the extracted vehicle speed-current function. This current command value produces a current based on the current command value in the power conversion circuit 2f, and this current is sent to the drive motor 6.

The Hi / Low switch 1 described above is
By providing it as an outdoor changeover switch, two types of speed limits can be set. Further, as the adjustment item of the vehicle speed limit by the memory 4, "not restricted" described in the description of the related art is made to correspond to, for example, Hi of the Hi / Low switch 1, so that the function similar to the conventional one can be satisfied. Further, it is possible to adjust and set arbitrary speed limits in the Hi area or the Low area of the memory corresponding to the Hi / Low switch 1. In addition, the adjustment of the vehicle speed limit is not possible by anyone as in the conventional case, and it may be so arranged that only the serviceman of the manufacturer can make the adjustment with the support of the forklift administrator, or the vehicle speed limit can be set at a position where it cannot be adjusted during driving. This adjustment is performed by setting a vehicle speed limit value in the memory 4 of the travel controller 2.

[0010]

As described above, according to the present invention, any two kinds of vehicle speed limits can be switched by the Hi / Low switch, and the vehicle speed limit value can be adjusted by the traveling controller instead of the operator. I chose

[Brief description of the drawings]

FIG. 1 is a simplified external view of a battery-powered forklift.

FIG. 2 is a block diagram mainly showing a travel controller

[Explanation of symbols]

 1 Hi / Low switch 2 Travel controller

Claims (1)

[Claims] 1. A Hi / Low switch for switching a speed limit value, and a vehicle speed set to be adjustable by an input of the Hi / Low switch is extracted and compared with a vehicle speed by a vehicle speed sensor. A speed controller for a battery-powered forklift having a travel controller that controls a drive motor so as not to exceed the limit.