JP2000072399A - Sudden turn preventing device for fork lift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the sudden turn of a fork lift and improve the stability of a vehicle. SOLUTION: This fork lift comprises a driving wheel for a vehicle, a driving motor 2 for rotating the driving wheel and an accelerator lever for operating the driving motor 2. A sudden turn preventing device 1 includes a stop detecting means 3 for detecting the stopped condition of the vehicle and a steering angle detecting means 4 for detecting the steering angle of the driving wheel. A controller 5 controls the operation of the driving motor 2 in accordance with stop data from the stop detecting means 3 and steering angle data from the steering angle detecting means 4 to control the acceleration of the vehicle during start-up.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift having a sudden turning prevention device with improved safety at the time of start of the forklift.

[0002]

2. Description of the Related Art A conventional forklift has driving wheels of a vehicle, a traveling motor for rotating the driving wheels, and an accelerator lever for operating the traveling motor.

[0003]

However, the above-mentioned conventional forklift has the following problems. That is, when the forklift is once stopped, the drive wheels may be lateral to the front-rear direction of the vehicle. On the other hand, when the forklift is started, the operator may erroneously recognize that the drive wheels are straight.

In this case, the operator normally operates the accelerator lever as in the case where the vehicle moves forward and backward. Therefore, normally, the acceleration at the time of starting the vehicle becomes unexpectedly large as compared with the case where the accelerator lever is operated when turning the vehicle.

[0005] Therefore, when the vehicle is started, a large acceleration is given in a state where the drive wheels are in the lateral direction, and there is a problem that the forklift turns sharply against the intention of the operator. In addition, the sudden turning of the forklift may cause the vehicle to come into contact with the surroundings, reduce the stability of the vehicle and the stability of the load, and cause the load to fall. Note that a reach forklift having a turning center provided in a vehicle so as to make a small turn is particularly easy to turn sharply, and such a problem is likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide an apparatus for preventing a forklift from turning sharply and capable of improving the stability of a vehicle while preventing the forklift from turning sharply. Things.

[0007]

According to the present invention, a driving wheel of a vehicle, a traveling motor for rotating the driving wheel, an accelerator lever for operating an operation of the traveling motor, and a sharp turning prevention are provided. A forklift including a stop detecting means for detecting a stop state of the vehicle, a steering angle detecting means for detecting a steering angle of the drive wheels, and A controller for controlling the operation of the traveling motor based on the stationary data and the steering angle data from the steering angle detecting means to thereby control the acceleration at the time of starting the vehicle. In the prevention device.

What is most notable in the present invention is that the vehicle stop detection means, the steering angle detection means, the traveling motor, and the controller are provided, and the acceleration of the vehicle is controlled based on the vehicle stop data and the steering angle data. This is the configuration.

The stop detecting means includes means for detecting a stop state from the speed of the vehicle by a vehicle speed sensor or the like.
Alternatively, means for detecting the stop state based on the operation position of the accelerator lever, non-operation time, etc., means for detecting the stop state based on the amount of current flowing to the traveling motor, presence or absence of current, and other various means may be employed. it can.

As the steering angle detecting means, for example, means for linearly detecting the steering angle of the drive wheel by a steering angle sensor or the like, or by providing a plurality of limit switches or non-contact sensors, etc. Means for detecting stepwise in two or more stages and other various means can be used. The steering angle is the direction of the drive wheels when the vehicle is moved forward and backward, that is, the angle between this direction and the direction of the drive wheels when the vehicle is turned right or left, based on the longitudinal axis of the vehicle. Say. Then, the steering angle is converted as steering angle data of at least two or more stages.

As described above, the controller controls the operation of the traveling motor based on the stop data and the steering angle data, and controls the acceleration of the vehicle.

Next, the operation of the present invention will be described. In the present invention, the operation of the traveling motor is controlled by the controller based on the stop data and the steering angle data as described above. Therefore, when it is determined from the stop data that the vehicle is in a stopped state, and when the steering angle data determines that the steering angle of the drive wheel is equal to or greater than a predetermined value, the traveling motor is controlled in accordance with the steering angle or the steering angle data. Operation is controlled.

Therefore, when the vehicle is stopped and the steering angle of the drive wheels is equal to or larger than the predetermined value (sideways), the accelerator lever is operated as usual,
The operation of the traveling motor is regulated by the controller. Then, the acceleration at the start of the vehicle is controlled to a safe low acceleration state.

As described above, according to the present invention, even when the vehicle is driven by operating the accelerator lever in the same manner as usual, the acceleration of the vehicle is changed to a safe acceleration in accordance with the stop data and the steering angle data. Can be regulated. Therefore, it is possible to prevent the forklift from turning sharply at the time of starting, thereby improving the stability of the vehicle and the load.

Next, it is preferable that the vehicle stop detecting means is a vehicle speed sensor.
In this case, the vehicle stop sensor can be commonly used as a vehicle speed sensor provided in a forklift.

Next, as in the third aspect of the present invention, the stop detecting means may be a current detecting sensor for detecting a current amount to the traveling motor. Next, as in the invention described in claim 4, the stop detecting means may be a position sensor for detecting an operation position of the accelerator lever.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment A sudden turning prevention device according to an embodiment of the present invention will be described.
This will be described with reference to FIGS. Sudden turning prevention device 1 of this example
As shown in FIGS. 2 and 3, a reach having a driving wheel 81 of a vehicle, a traveling motor 2 for rotating the driving wheel 81, and an accelerator lever 83 for operating the traveling motor 2 is provided. It is arranged on the forklift 8.

As shown in FIG. 1, the sudden turning prevention device 1 includes a stop detecting means 3 for detecting a stop state of the vehicle,
A steering angle detecting means 4 for detecting a steering angle of the drive wheel 81; The sudden turning prevention device 1 controls the operation of the traveling motor 2 on the basis of the stop data from the stop detection means 3 and the steering angle data from the steering angle detection means 4 to control the start of the vehicle. And a controller 5 for controlling the acceleration.

The details will be described below. The stop detecting means 3 is a vehicle speed sensor, and is installed above the traveling motor 2 as shown in FIGS. And the stop detecting means 3
Detects that the vehicle is in a running state when the vehicle speed is greater than zero, detects that the vehicle is in a stopped state when the vehicle speed is zero, and sends any of the stop data to the controller 5.
It is configured to send to.

The steering angle detecting means 4 is a steering angle sensor, and is installed on the turning gear 21 of the traveling motor 2 as shown in FIGS. Then, the steering angle θ of the drive wheel 81
Is determined by the rotation of the turning gear 21. The steering angle θ of the drive wheel 81 is, as shown in FIG. 4, the direction of the drive wheel 81 when the vehicle is moved forward and backward, that is, when the vehicle is turned right or left with the longitudinal axis of the vehicle as the reference line B. Is the angle between the reference line B and the turning line C when the direction of the driving wheel 81 is the turning line C.

The steering angle θ can take a value up to about 90 degrees, which is the turning end θe, as shown in FIG. When the steering angle θ takes a value smaller than the boundary angle θs of about 45 degrees, the turning radius of the vehicle is large and the vehicle turns gently. On the other hand, when the steering angle θ takes a value from the boundary angle θs to the turning end θe, the turning radius of the vehicle is small, and the vehicle turns sharply.

The steering angle detecting means 4 detects that the steering angle θ is smaller than the boundary angle θs or detects that the steering angle θ is equal to or larger than the boundary angle θs. 5 is transmitted. In addition,
The steering angle θ can be on both left and right sides with respect to the reference line B. Therefore, the steering angle θ at the time of turning left is represented by minus, and the steering angle θ at the time of turning right is represented by plus, and it is possible to distinguish between left and right. However, in order to simplify the description, both are represented by plus.

Further, as shown in FIG. 5, the controller 5 in this embodiment first takes in the stop data and the steering angle data into the controller. Next, if it is determined in step (hereinafter referred to as S) 1 that the vehicle is in a stopped state based on the stop data, the process proceeds to S2. If it is determined in S2 that the steering angle θ is equal to or larger than the boundary angle θs from the steering angle data, the process proceeds to S3.
The operation of the traveling motor 2 is regulated more than usual. As a result, the acceleration at the start of the vehicle is lower than usual.

On the other hand, if it is determined in S1 that the vehicle is in a running state from the stop data, the process proceeds to S4,
The operation of the traveling motor 2 is made the same as usual. This gives
The acceleration when the vehicle is running remains normal. Also, S2
When it is determined from the above steering angle data that the steering angle θ is smaller than the boundary angle θs, the process proceeds to S5, and the operation of the traveling motor 2 is made the same as usual. As a result, the acceleration at the start of the vehicle remains normal.

As shown in FIG. 6, the controller 5 applies a voltage Vo of, for example, 45 volts to the traveling motor 2 when the accelerator lever 83 is operated in the same manner as usual. It is. Then, the controller 5 regulates the operation of the traveling motor 2 based on the stop data and the steering angle data.

That is, if it is determined from the stop data that the vehicle is in a stopped state and the steering angle θ is greater than or equal to the boundary angle θs from the steering angle data, the accelerator lever 83 may be operated in the same manner as described above. The voltage applied to the traveling motor 2 is regulated to, for example, 30 volts which is lower than the voltage Vo. As a result, the operation of the traveling motor 2 is regulated, so that the acceleration when the vehicle starts can be controlled to a low acceleration state. The controller 5 can also control the traveling speed of the vehicle.

As described above, in the above-mentioned sudden turning prevention device 1, when the vehicle is in a stopped state and the steering angle θ is equal to or larger than the boundary angle θs, the acceleration at the time of starting is not set to a lower acceleration state than usual ( S3) If the vehicle is in a running state, the acceleration during running is maintained as usual (S4). If the vehicle is in a stopped state and the steering angle θ is smaller than the boundary angle θs, the acceleration at the time of starting is increased. Is controlled to be maintained as usual (S5).

Next, the operation of the present embodiment will be described. In the sudden turning prevention device 1 of the present embodiment, the operation of the traveling motor 2 is controlled by the controller 5 based on the stopping data and the steering angle data as described above. Therefore, when it is determined from the stop data that the vehicle is in the stopped state, and it is determined from the steering angle data that the steering angle θ of the drive wheel 81 is greater than or equal to the boundary angle θs, the steering angle θ
The operation of the traveling motor 2 is controlled in accordance with.

Therefore, when the vehicle is stopped and the driving wheels 8
When the steering angle θ is equal to or larger than the boundary angle θs (sideways), the operation of the traveling motor 2 is regulated by the controller 5 even though the accelerator lever 83 is operated as usual. Then, the acceleration at the start of the vehicle is controlled to a safe low acceleration state.

As described above, in the present embodiment, even when the vehicle is driven by operating the accelerator lever 83 in the same manner as usual, the acceleration of the vehicle is changed to a safe acceleration according to the stop data and the steering angle data. Can be regulated. Therefore, it is possible to prevent the reach forklift 8 from turning sharply at the time of starting, thereby improving the stability of the vehicle and the load.

The sudden turning prevention device 1 controls the operation of the traveling motor 2 on the basis of the steering angle data, so that it is a forklift, particularly a reach forklift (FIG. 7) that can turn a small turn. , It is possible to reliably prevent sudden turning.

In this embodiment, the change rate of the acceleration is changed stepwise based on the two steering angle data. However, the change rate of the acceleration is calculated based on a large number of linearly detected steering angles. It can be changed continuously based on the data.

Although a vehicle speed sensor is used as the vehicle stop detecting means 3, a current detecting sensor for detecting the amount of current to the traveling motor 2, a position sensor for detecting the operating position of the accelerator lever 83, and the like are used. It can also be used.

[0034]

As described above, according to the present invention, it is possible to provide an apparatus for preventing a forklift from turning sharply while preventing the forklift from turning sharply and improving the stability of the vehicle.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a configuration of a sudden turning prevention device according to an embodiment.

FIG. 2A is an explanatory plan view and FIG. 2B is a side view of the reach forklift according to the embodiment.

FIG. 3 is a front view of the reach forklift according to the embodiment.

FIG. 4 is an explanatory diagram showing a steering angle in the embodiment.

FIG. 5 is a flowchart showing a control flow in the embodiment.

FIG. 6 is a diagram showing a relationship between a steering angle and a voltage applied to a traveling motor in the embodiment.

FIG. 7 is a perspective view of a reach forklift according to the embodiment.

[Explanation of symbols]

 1. . . Sudden turn prevention device, 2. . . Traveling motor, 3. . . Stop detection means, 4. . . 4. steering angle detection means; . . Controller, 8. . . Reach forklift, 81. . . Drive wheel, 83. . . Accelerator lever,

Claims (4)

[Claims] 1. A forklift having a driving wheel of a vehicle, a traveling motor for rotating the driving wheel, an accelerator lever for operating an operation of the traveling motor, and a sudden turning prevention device, The abrupt turning prevention device includes a vehicle stop detecting means for detecting a stop state of the vehicle, a steering angle detecting means for detecting a steering angle of the drive wheel, a stop data from the vehicle stop detecting means, and a stop signal from the steering angle detecting means. A controller for controlling the operation of the traveling motor based on the steering angle data to control the acceleration at the time of starting of the vehicle. 2. The device according to claim 1, wherein the stop detecting means is a vehicle speed sensor. 3. The forklift turning prevention device according to claim 1, wherein the stop detection means is a current detection sensor for detecting a current amount to the traveling motor. 4. The forklift according to claim 1, wherein said stop detecting means is a position sensor for detecting an operation position of said accelerator lever.