JPS6192931A - Vehicle speed control device of battery fork lift - Google Patents

Abstract

PURPOSE:To assure stable operation of turning by automatically controlling a vehicle speed to one corresponding to an angle of rotation of an operating wheel, while automatically controlling the vehicle speed to one corresponding to an angular velocity of turning of the operating wheel when said angular velocity is greater. CONSTITUTION:An output from a potentionmeter 9 having resistance varied in response to an angle of turning of a operating wheel of fork lift is employed as a vehicle speed signal V1 via a converter 24, and entered into a comparison operating circuit 25. In addition, an arithmetic operation circuit 26b detects in succession an angle of rotation per unit time, i.e., angular velocity of turning on the basis of the output from the poteniometer 9, and enters an output there from into said circuit 25 as a vehicle speed signal V2 via a converter 27. Control signals respectively corresponding to V2 when V1>V2 and to V1 when V1<V2 are sent to a second circuit 23 of a controller 21, and a smaller signal between an output signal from the same circuit 23 and an output signal from a first circuit 22 controlled in response to operation of an accelerator 7 is sent to a chopper 20 for controlling a travelling motor 5.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a device for controlling the vehicle speed of a battery forklift truck.

Conventional technology A battery and an electric motor are connected through a chopper controlled by an accelerator, and current is sent to the electric motor according to the operating stroke of the accelerator to control the rotational speed of the electric motor, thereby driving the electric motor. A vehicle speed control device controls the rotational speed of the drive wheels so that the traveling speed, that is, the vehicle speed, corresponds to the operating stroke of the accelerator.

Problem to be Solved by the Invention Since the vehicle speed depends on the operating stroke of the accelerator, when turning to the left or right, unless the accelerator is operated in accordance with the turning radius to reduce the vehicle speed, the vehicle body will move a large distance. ,
This is dangerous because the sudden exertion of mental force may cause the vehicle to lose stability and cause the vehicle to jump or fall.

To prevent this, it is possible to reduce the vehicle speed by operating the accelerator according to the turning radius, but it is extremely difficult and requires skill to operate the steering wheel and the accelerator at the same time. Since the vehicle speed of a forklift is slow, there is no intuitive will to reduce the vehicle speed, so it is virtually impossible to decelerate by operating the accelerator when turning.

Means for solving the problem and operation A means for continuously detecting the turning angle of the steering wheel and continuously outputting a vehicle speed signal corresponding to the turning angle, and a means for continuously outputting a vehicle speed signal corresponding to the turning angle, By providing means for outputting a vehicle speed signal and a comparison calculation circuit that sends the smaller of the two vehicle speed signals to the controller, it is possible to automatically control the vehicle speed to correspond to the turning angle, and also to adjust the turning speed to the turning speed when making a sharp turn. The vehicle speed can be automatically controlled according to the vehicle speed.

Embodiment FIG. 4 is an overall front view, and a driving wheel 2 and a steering wheel 3 are mounted on the front and rear of a vehicle body 1, and the driving wheel 2 is driven by an electric motor 5 supplied with current from a battery 4. At the same time, the steering wheels 3 are controlled to be steered left and right by the handle 6, and the current supplied to the electric motor 5 is controlled by the operating stroke of the axle self.

As shown in FIG. 5, a small gear II fixed to a shaft 10 of a potentiometer 9 meshes with a large gear 8 that rotates together with the steering wheel 3. As a result, the resistance value of the potentiometer 9 changes as shown in FIG. 6, so that the turning angle of the steering wheel 3 can be continuously detected by the resistance M of the potentiometer 9.

FIG. 1 is a vehicle speed control circuit diagram, in which the battery 4 and the electric motor 5 are connected via a chopper 20, the chopper 20 is controlled by a signal from a controller 21, and the controller 21 is controlled by the operating stroke of the accelerator. A first circuit 22 that outputs a signal in accordance with the output of a comparison calculation circuit to be described later, and a second circuit 23 that outputs a signal in accordance with the output of a comparison calculation circuit described later. A signal is sent from the controller 21 to the chopper 20 to control the current supplied to the electric motor 5.

The output of the potentiometer 9 is sent via a converter 24 to a comparison calculation circuit 25 as a vehicle speed signal l, and is also sent to a calculation circuit 26 where the turning angle per unit time, that is, the turning angular velocity is continuously determined. The turning angular velocity is sent to the comparison calculation circuit 25 via the converter 27 as a vehicle speed signal v2.

A comparison calculation circuit 25 compares and calculates vehicle speed signals v1 and v2,
When h is small, the control signal corresponding to the signal of v2 is sent to the second
After that, a control signal corresponding to the vl signal is sent to the second circuit 23, and when ■1 is small, a control signal corresponding to the signal is sent to the second circuit 23.

Because of this, the vehicle speed can be automatically controlled as shown in Figure 2 according to the turning angle, and when the turning angular velocity is large due to a sharp turn, the vehicle speed can be automatically controlled as shown in Figure 3. Ru.

Note that a potentiometer in the 90's or a second encoder may be used. In other words, it is sufficient to provide means for continuously detecting the turning angle of the steering wheels.

Effects of the Invention The vehicle speed can be automatically controlled to correspond to the turning angle of the steering wheel 3, and when the turning angular speed of the steering wheel 3 is large, the vehicle speed can be automatically controlled to the speed corresponding to the turning angular speed, and when turning, the vehicle speed can be automatically controlled to correspond to the turning angle of the steering wheel 3. It is possible to improve the stability of the vehicle body and prevent it from jumping up or falling over without having to operate the vehicle.

Further, since the continuous turning angle of the steering wheels 3 can be detected and the vehicle speed can be continuously controlled based on the detection, smooth vehicle speed control can be performed and smooth turning can be achieved.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a vehicle speed control circuit diagram, FIG. 2 is a table showing the relationship between the resistance value of a potentiometer and vehicle speed, and FIG. 3 is a diagram showing the relationship between vehicle speed and turning angular velocity. Table diagram, Figure 4 is the overall front view of the battery forklift, Figure 5 is
The figure is a plan view of the steering wheel and the potentiometer, and FIG. 6 is a table showing the relationship between the turning angle and the resistance value of the potentiometer. 1 is the vehicle body, 2 is the drive wheel, 3 is the steering wheel, 4 is the battery, 5
is an electric motor, 20 is a chopper, 21 is a controller,
25 is a comparison calculation circuit.

Claims (1)

[Claims] means for connecting an electric motor 5 that drives the driving wheels 2 to a battery 4 via a chopper 20, continuously detecting the turning angle of the steering wheel 3, and continuously outputting a vehicle speed signal corresponding to the turning angle; , means for outputting a vehicle speed signal corresponding to the turning angular velocity of the steering wheel 3; a comparison calculation circuit 25 for comparing this vehicle speed signal with the vehicle speed signal and outputting a vehicle speed signal having a small value; and this comparison calculation circuit 25. The chopper 2
1. A vehicle speed control device for a battery forklift, characterized in that a controller 21 is provided to control the speed of a battery forklift.