JP2003306160A - Cargo handling vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance a driving operability by optionally changing a steering wheel sensitivity according to the liking of a driving operator. <P>SOLUTION: In the cargo handling vehicle provided with an electric steering device, a steering wheel operation angle detector 22 for detecting an operation angle θh of a steering wheel 14 and a steering motor 29 for steering a steered wheel 8 is driven/controlled based on a detection output of the steering wheel operation angle detector. The electric steering device is provided with a steering wheel sensitivity-changing means 33 for changing a variation ratio of a steering angle θt of the steered wheel against the steering wheel operation angle detected by the steering wheel operation angle detector. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cargo handling vehicle equipped with an electric steering device.

[0002]

2. Description of the Related Art Conventionally, some cargo handling vehicles are equipped with an electric steering device for electrically controlling the steering wheels based on the operation of the steering wheel. At this time, the steering wheel and the steering wheel are mechanically operated. The steering wheel and the steering wheel may not be mechanically connected to each other. Here, a reach type forklift as shown in FIG. 4 will be described as an example of such a cargo handling vehicle.

The reach type forklift shown in FIG.
A pair of left and right straddle arms 2 from the vehicle body 1 toward the front
The straddle arm 2 is provided with a pair of left and right masts 3 that move forward and backward along the straddle arm 2. A fork 4 for mounting a load is mounted on the mast 3 via a lift bracket 6. It is mounted so that it can be raised and lowered.
Road wheels 7 are provided at the tip of each of the left and right straddle arms 2, and steering wheels 8 also serving as drive wheels are provided at the rear of the vehicle body 1. Furthermore, car body 1
A driving operation unit 11 is secured in a location adjacent to the rear driver's seat 10. The driving operation unit 11 includes a cargo handling operation lever 12, a travel lever 13, and a steering wheel 14 for steering.
Etc. are provided.

Further, the vehicle body 1 is provided with an electric steering device as shown in FIG. 5 for steering and controlling the steered wheels 8 according to the operation of the steering wheel 14.

That is, in this electric steering apparatus, the steering wheel 14 and the steering wheel 8 are not mechanically connected, but instead, the steering wheel shaft 17 extends from the center of the steering wheel 14 and is provided at the lower end thereof. First sprocket 18
The second sprocket 19 is connected to the first sprocket 18 via a chain 20. The second sprocket 19 is provided with a steering wheel operation angle detector 22 such as a rotary encoder that detects an operation angle of the steering wheel 14, and a detection output of the steering wheel operation angle detector 22 (a pulse corresponding to the steering wheel operation angle) is provided. After the output) is counted by the counter 23, the count value is input to the controller 24. Further, the bracket 26 supporting the steered wheels 8 has a first
A gear 27 is attached, a second gear 28 meshes with the first gear 27, and an output shaft of a steering motor 29 is attached to the second gear 28.

Then, the controller 24 obtains the steering angle of the steered wheels 8 corresponding to the detected output of the steering wheel operation angle detector 22, and drives the motor drive circuit 30 so as to obtain the steering angle. The steering motor 29 is drive-controlled via the drive. As a result, the steered wheels 8 are steered in a predetermined direction according to the operation of the steering wheel 14.

A forklift equipped with such an electric steering system has a steering wheel 14 and steering wheels 8.
Since and are not mechanically connected, the handle can be operated with a very light operating force.
Even if 4 is made small, there is an advantage that operability does not easily deteriorate.

[0008]

By the way, in the conventional forklift shown in FIGS. 4 and 5, the electric steering device has a change ratio of the steering angle of the steered wheels 8 according to the operation angle of the steering wheel 14 (hereinafter referred to as the steering wheel). Also called sensitivity)
Has a uniquely defined structure. That is, since the controller 24 performs a process of obtaining the steering angle of the steered wheels 8 while keeping the relative relationship between the steering wheel operation angle detected by the steering wheel operation angle detector 22 and the steering angle of the steered wheels 8 constant, the steering wheel sensitivity is increased. Will always be the same. In an electric steering device in which a steering wheel and steered wheels are mechanically connected, for example, the steering wheel sensitivity is represented by the gear ratio between the first gear 27 and the second gear 28. Also in this case, the steering wheel sensitivity is uniquely defined.

Therefore, when the steering wheel sensitivity is set low, the change in the steering angle of the steered wheels 8 with respect to the steering wheel operation becomes small. Therefore, in order for the steered wheels 8 to have a predetermined steering angle, Since 14 must be turned many times, the handle operation becomes complicated. On the contrary, when the steering wheel sensitivity is set high, the change in the steering angle of the steered wheels 8 with respect to the steering wheel operation becomes large, and the vehicle body 1
The straightness of the vehicle deteriorates.

Since such a steering wheel sensitivity has a different suitability depending on the situation such as the experience of the driver and the contents of the cargo handling work, the driver himself can set it arbitrarily according to his own preference and various situations. It is preferable to make it easy to use a cargo handling vehicle such as a forklift.

The present invention has been made to solve the above-mentioned problems, and the steering sensitivity of the electric steering apparatus can be changed according to the preference of the driving operator to improve the driving operability. The purpose is to provide a cargo handling vehicle.

[0012]

In order to achieve the above-mentioned object, the present invention is provided with a steering wheel operation angle detector for detecting an operation angle of a steering wheel, and the steering wheel operation angle detector outputs the detected output. A cargo handling vehicle including an electric steering device configured to drive and control a steering motor that steers the steered wheels based on the following configuration.

That is, according to the first aspect of the invention, the electric steering apparatus changes the steering wheel sensitivity changing means for changing the rate of change of the steering angle of the steered wheels with respect to the steering wheel operating angle detected by the steering wheel operating angle detector. Is equipped with.

Thus, the steering wheel sensitivity changing means changes the steering wheel steering angle change rate with respect to the steering wheel operation angle, that is, the steering wheel sensitivity, according to the driver's needs such as the degree of experience of the driver and the contents of the cargo handling work. Since it can be changed, the driving operability of the cargo handling vehicle can be improved.
For example, if you want to work while steering the steered wheels quickly, you can increase the steering wheel sensitivity to change the direction of the steered wheels significantly with fewer steering wheel operations. If desired, the steering wheel sensitivity can be lowered so that the steering wheels hardly change direction even if the steering wheel is operated a little.
Of course, in addition to this, when the driver feels that it is difficult to operate due to the size and shape of the steering wheel, the relative positional relationship between the handle and the driver, etc. Can be improved.

According to a second aspect of the invention, in the configuration of the first aspect of the invention, the electric steering device is:
The steering angle of the steered wheels is determined by multiplying the steering wheel operation angle by a conversion coefficient, and the motor is drive-controlled so as to obtain the determined steering angle of the steered wheels. The means includes an input operation unit that inputs a handle sensitivity change signal from the outside, and a coefficient changing unit that changes the conversion coefficient according to the handle sensitivity change signal externally input from the input operation unit. I am trying.

As a result, the driver can change the steering wheel sensitivity by operating the input operation section from the outside and inputting the steering wheel sensitivity change signal, so that the steering wheel sensitivity can be easily changed. For example, when the driver operates the input operation unit to increase the steering wheel sensitivity, the steering wheel sensitivity change signal for increasing the steering wheel sensitivity is input from the input operation unit to the coefficient changing unit, and the coefficient changing unit changes the conversion coefficient. Change to a larger value. As a result, the steering angle of the steered wheels is determined to be a larger value even if the steering wheel operation angle is the same, and the motor is driven to obtain the determined steering angle of the steered wheels. You will be able to change the direction of the steered wheels. On the contrary, when the driver operates the input operation unit so as to reduce the steering wheel sensitivity, the steering wheel sensitivity change signal for lowering the steering wheel sensitivity is input from the input operation unit to the coefficient changing unit, and the coefficient changing unit changes the conversion coefficient. Change to a smaller value. As a result, even if the steering wheel operating angle is the same, the steering angle of the steered wheels is determined to be a smaller value, and the motor is driven to obtain the determined steering angle of the steered wheels. Without it, the direction of the steered wheels cannot be changed. In addition, even when a plurality of driver operators share the same cargo handling vehicle, since each driver operator can operate the input operation unit to change the steering wheel sensitivity,
There is no problem. The input operation unit may be a push button, an adjustment knob, or the like, and the size and arrangement thereof may be determined so as not to interfere with other operations (for example, handle operation and cargo handling operation). Further, the amount by which the coefficient changing unit changes the conversion coefficient may be set so as to increase as the amount of operation of the input operation unit and the number of operations increase. By doing so, the driver can intuitively handle the steering wheel. The sensitivity can be changed.

According to a third aspect of the present invention, in the configuration of the second aspect of the present invention, there is provided display means for displaying an image of the change state of the conversion coefficient by the coefficient changing section according to the operation of the handle sensitivity changing means. Is characterized by.

As a result, the driver can easily confirm how much the steering wheel sensitivity is changed by looking at the image displayed on the display means, so that the steering wheel sensitivity can be changed more easily. Further, it becomes possible to eliminate a mistake such as making an erroneous change when changing the steering wheel sensitivity, and the driver can surely change the steering wheel sensitivity to a desired one. It should be noted that as the image display of the display means, a picture or a character representing the change state of the conversion coefficient may be displayed in a size and color that the driver can easily see. Further, by disposing the display unit adjacent to the input operation unit, it becomes possible to easily operate the input operation unit while looking at the display unit.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, here
For the sake of convenience of explanation, a reach-type forklift will be described as an example, but the present invention is not limited to the reach-type forklift, but can be widely applied to various cargo-handling vehicles including an electric steering device.

FIG. 1 is a block diagram showing a main configuration of a reach type forklift having an electric steering device according to an embodiment of the present invention. In addition, in the entire structure of the reach type forklift according to the present embodiment and the basic structure of the electric steering device, the same components as those of the conventional one shown in FIGS. Description will be made with reference to these figures.

In the reach type forklift according to this embodiment, as shown in FIG. 4, a pair of left and right straddle arms 2 are extended from the lower part of the vehicle body 1 toward the front, and the straddle arm 2 is advanced and retracted along the straddle arm 2. A pair of left and right operating masts 3 are erected. A fork 4 for loading luggage is mounted on these masts 3 by a lift bracket 6
It is attached so that it can be raised and lowered via. In addition, the road wheels 7 are respectively attached to the tips of the left and right straddle arms 2.
Is provided, and a steering wheel 8 that also serves as a drive wheel is provided at the lower rear portion of the vehicle body 1. Further, a driver's seat 10 is provided at the rear of the vehicle body 1, and a driving operation unit 11 is secured at a location adjacent to the driver's seat 10. This operation unit 1
1, a cargo handling operation lever 12 for cargo handling operations such as lifting and tilting of the fork 4, a traveling lever 13 for adjusting the traveling speed of the forklift, and a steering handle 14 are provided.

In the electric steering apparatus according to this embodiment, as shown in FIG. 5, a first sprocket 18 is attached to a lower end portion of a handle shaft 17 extending from the center of a handle 14 which is rotated by a driver. A second sprocket 19 is connected to the first sprocket 18 via a chain 20. The second sprocket 19 is provided with a steering wheel operation angle detector 22 such as a rotary encoder that detects an operation angle of the steering wheel 14, and a detection output of the steering wheel operation angle detector 22 (a pulse corresponding to the steering wheel operation angle) is provided. The output) is counted by the counter 23. The counter 23 is connected to the input side of the controller 24. Therefore, the first sprocket 18 rotates as the handle 14 is rotated by the driver, and the rotation of the first sprocket 18 causes the rotation of the chain 2
It is transmitted to the second sprocket 19 via 0, and the second sprocket 19 rotates. The rotation of the second sprocket 19 is detected by the steering wheel operation angle detector 22, and the operation angle of the steering wheel 14 is detected. The detection output is counted by the counter 23 and input to the controller 24 as a count value. To be done.

Further, as shown in FIG. 5, a first gear 27 is attached to a steering shaft 32 of a bracket 26 that supports the steered wheels 8, and a second gear 28 is meshed with the first gear 27 to form a second gear. An output shaft of a steering motor 29 is attached to the gear 28. Therefore, when the steering motor 29 is driven, the second gear 28 rotates, and the rotation thereof causes the first gear 2 to rotate.
The steering wheel 8 is steered by being transmitted to the vehicle 7 and rotating the steering wheel 8 together with the bracket 26 about the steering shaft 32.

Then, the controller 24 obtains the steering angle of the steered wheels 8 corresponding to the input from the counter 23, and the steering angle is obtained via the motor drive circuit 30 so that the steering angle can be obtained. The motor 29 is drive-controlled. That is, the steering wheel operation angle input as a count value from the counter 23 is θh, and the steering angle of the steered wheels 8 is θ.
If t and the conversion coefficient are k, the controller 24
= Kθh (1) As shown in (1), the steering wheel operation angle θh is multiplied by the conversion coefficient k to obtain the steering angle θt, and the steering angle θt is calculated through the motor drive circuit 30 according to the steering angle θt. Control for driving the motor 29 is performed. As a result, the steered wheels 8 are steered in a predetermined direction according to the operation of the steering wheel 14. Incidentally, 31 is the first gear 2
7 is a steering angle detector attached to the steering shaft 32 of the steering wheel 8 to detect the actual steering angle of the steered wheels 8.
Is set via the motor drive circuit 30 so that the deviation between the steering angle θt of the steered wheels 8 obtained by the equation (1) and the actual steering angle of the steered wheels 8 detected by the steering angle detector becomes zero. By driving the steering motor 29 in this manner, control is performed so that the steering angle θt of the steered wheels 8 obtained by the equation (1) is obtained.

It is assumed that the steering wheel operating angle θh increases in the direction in which the steering wheel 14 rotates clockwise in plan view, and the steering angle θt increases in the direction in which the steered wheels 8 are steered clockwise in plan view. , The conversion coefficient k is a positive value. That is, in this embodiment, the direction in which the driver operates the steering wheel 14 and the direction in which the steered wheels 8 are steered are the same.

The feature of this embodiment is that, as shown in FIG. 1, the change ratio of the steering angle of the steered wheels 8 with respect to the steering wheel operating angle detected by the steering wheel operating angle detector 22, that is, the steering wheel sensitivity for changing the steering wheel sensitivity. That is, the changing unit 33 is provided.

The steering wheel sensitivity changing means 33 has a (+) button 37 and a (-) button 38 for inputting a steering wheel sensitivity changing signal from the outside, and these respective buttons 37, 38.
The coefficient changing unit 40 that changes the conversion coefficient k in the above equation (1) according to the steering wheel sensitivity change signal input from
It has and. Then, each time the (+) button 37 is pressed, a handle sensitivity change signal for increasing the conversion coefficient k is input to the coefficient changing unit 40, and the coefficient changing unit 40 increases the conversion coefficient k step by step. Also, the (-) button 3
Each time 8 is pressed, a handle sensitivity change signal for reducing the conversion coefficient k is input to the coefficient changing unit 40, and the conversion coefficient k is gradually reduced. As is clear from the equation (1), in the present embodiment, increasing the conversion coefficient k is to increase the steering wheel sensitivity, and decreasing the conversion coefficient k is to decrease the steering wheel sensitivity. Is.

The above (+) button 37 and (-) button 38 are both arranged in the driving operation section 11, and the coefficient changing section 40 is constructed by loading a predetermined program into the controller 24. There is.

Further, in this embodiment, a screen changeover switch 34, a button for advancing the adjustment procedure (hereinafter referred to as a forward button) 35, a button for returning the adjustment procedure (hereinafter referred to as a return button) 36, a color LCD. A display 41 including the above, and a display control unit 42 are provided. Then, these screen changeover switches 34,
The forward button 35, the return button 36, and the display 41 are all the same as the above (+) in the driving operation unit 11.
The button 37 and the (-) button 38 are arranged close to each other.

Here, the screen changeover switch 34 is for alternately changing over the display content of the display 41 between the normal display mode for cargo handling operation and the display mode for steering wheel sensitivity adjustment. The return button 36 is for sequentially changing the display content in the display mode for adjusting the steering wheel sensitivity. The display control means 42 controls the display 41 so that a screen corresponding to the operation of the screen changeover switch 34 and the buttons 35, 36, 37, 38 is displayed.

The (+) button 37 and the (-) button 38 are used as input operation sections for inputting a steering wheel sensitivity change signal in the present invention, and the display 4 is used.
1 and the display control means 42 respectively correspond to the display means in the present invention.

Next, in the reach type forklift having the above structure, the processing operation when changing the steering wheel sensitivity of the electric steering system will be described with reference to the flowchart shown in FIG. 2 and the explanatory view shown in FIG.

Now, when the screen changeover switch 34 is not operated at all, the controller 24 provides the display control means 42 with information indicating that it is in the normal display mode for cargo handling operation, and accordingly, the display control means 42. Displays an image having the contents as shown in FIG. 3A on the display 41 (S1). That is, the display 41 displays the speedometer, the remaining battery capacity meter, the cumulative operating time, the current date and time, etc. on the screen.

With such a screen displayed,
When the screen changeover switch 34 is operated (S2), the display control means 42 displays a screen for steering wheel sensitivity adjustment on the display 41 as shown in FIG. 3B (S3).

When the forward button 35 is not operated and the (+) button 37 is operated while the steering wheel sensitivity adjustment screen is displayed (S4,
S5), and accordingly, the coefficient changing unit 4 of the controller 24
When 0, the conversion coefficient k in the above equation (1) is sequentially increased (S6), while the display control means 42, as shown in FIG. 3C, changes the conversion coefficient k in response to the operation of the (+) button 37. k
Is displayed (that is, the steering wheel sensitivity is increased).

In this embodiment, as shown in FIGS. 3 (b) to 3 (d), the conversion coefficient k is represented by a vertically long rectangle displayed in order from the left side of the screen, and the conversion coefficient k increases. If so, the number of displayed rectangles increases, and if the conversion coefficient k decreases, the number of displayed rectangles decreases. The image display of the change state of the conversion coefficient in the present invention is not limited to such display, and the driver operator can intuitively recognize the change state of the conversion coefficient by displaying the conversion coefficient k as a number. It may be displayed like this. Further, the pictures and characters to be displayed so that the change status of the conversion coefficient can be recognized may be displayed in a size and color that the driver can easily see, as in the case of a screen display such as a speedometer or a battery remaining capacity meter.

Further, while the steering wheel sensitivity adjusting screen shown in FIG. 3B is displayed, the forward button 3
When the (-) button 38 is operated without operating 5 (S4, S5, S7), the coefficient changing unit 40 of the controller 24 responds to the conversion coefficient k in the equation (1) sequentially. While decreasing (S8), the display control means 42
Displays the situation in which the conversion coefficient k decreases (that is, the steering wheel sensitivity decreases) according to the operation of the (−) button 38, as shown in FIG. 3D.

In this way, when the forward button 35 is operated after the (+) button 37 and the (-) button 38 are operated to adjust the steering wheel sensitivity (S4), the controller 24 responds to this by confirming the steering wheel sensitivity. Since the information to shift to the mode is given to the display control means 42, the display control means 42 displays the steering wheel sensitivity confirmation screen as shown in FIG. 3E on the display 41 (S).
9).

Therefore, the driver actually uses the steering wheel 14
Is operated to confirm the handle sensitivity (S10). At that time, if the driver feels that the steering wheel sensitivity set in S5 to S8 is inappropriate, he or she presses the return button 36 (S11) to adjust the steering wheel sensitivity shown in FIG. Since the screen display state is returned (S3), the handlebar sensitivity can be readjusted by operating the (+) button 37 and the (-) button 38 again.

In S10, when the driver actually checks the steering wheel sensitivity by operating the steering wheel 14, if it is determined that the steering wheel sensitivity set in S5 to S8 is appropriate, Press the next button 36 (S
12). Then, in response to this, the controller 24 provides the display control means 42 with information indicating that the steering wheel sensitivity determination mode is to be entered, and the display control means 42 causes the display 41 to display the steering wheel sensitivity as shown in FIG. A confirmation screen is displayed (S13).

Further, when the forward button 36 is operated to shift to the screen for confirming the steering wheel sensitivity, the controller 24 changes the conversion coefficient k after being changed by the coefficient changing unit 40.
The value of is stored in a memory (not shown) (S14). After that, the controller 24 performs a process of converting the steering wheel operation angle θh into the steering angle θt of the steered wheels 8 by the equation (1) using the changed conversion coefficient k value stored in the memory.

With the screen for confirming the steering wheel sensitivity as shown in FIG. 3 (f) displayed, the screen change switch 3
When 4 is operated (S15), the process returns to S1, and the display control means 42 displays the screen as shown in FIG.

As described above, according to this embodiment, since each driving operator can actually operate the steering wheel 14 to adjust the steering wheel sensitivity so as to feel appropriate,
The operability of the cargo handling vehicle can be improved. Further, since the display corresponding to the steering wheel sensitivity is displayed on the display 41 during the adjustment, the current steering wheel sensitivity can be visually recognized and the steering wheel sensitivity can be easily changed.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention.

[0045]

According to the forklift equipped with the electric steering device of the present invention, the following effects can be obtained.

According to the first aspect of the invention, since the steering wheel sensitivity changing means for changing the rate of change of the steering angle of the steered wheels with respect to the steering wheel operating angle detected by the steering wheel operating angle detector is provided, the driver is It is possible to change the setting so that the steering wheel sensitivity is appropriate according to the degree of experience and the contents of cargo handling work. Therefore, it becomes possible to enhance the driving operability of the cargo handling vehicle.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, since the steering wheel sensitivity can be adjusted by operating the input operation portion and changing the conversion coefficient by the coefficient changing portion, the steering wheel sensitivity can be adjusted. Can be easily adjusted.

According to the third aspect of the invention, in addition to the effect of the second aspect of the invention, by displaying the degree of adjustment of the steering wheel sensitivity on the display means, the degree of change of the steering wheel sensitivity can be visually checked easily. Can be confirmed. Therefore, the steering wheel sensitivity can be changed more easily.

[Brief description of drawings]

FIG. 1 is a block diagram showing a main configuration of a forklift including an electric steering device according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining an operation in the case of adjusting the steering wheel sensitivity of the electric steering device in the embodiment of the present invention.

FIG. 3 is an explanatory diagram showing an example of contents displayed on a display according to the flowchart shown in FIG. 2 in the embodiment of the present invention.

FIG. 4 is a side view of a conventional reach type forklift.

5 is a configuration diagram of an electric steering device provided in the forklift illustrated in FIG.

[Explanation of symbols]

8 steering wheels 14 handle 22 Handle angle detector 24 controller 29 motor 33 Handle sensitivity changing means 37 (+) button (input operation part) 38 (-) button (input operation section) 40 coefficient variable part 41 display 42 display control means

Claims (3)

[Claims] 1. A steering wheel operation angle detector for detecting an operation angle of a steering wheel is provided, and a steering motor for steering a steered wheel is drive-controlled based on a detection output of the steering wheel operation angle detector. In a cargo handling vehicle equipped with the electric steering device, the electric steering device changes steering wheel sensitivity to change a rate of change of the steering angle of the steered wheels with respect to a steering wheel operating angle detected by the steering wheel operating angle detector. A cargo handling vehicle comprising a means. 2. The electric steering apparatus determines the steering angle of the steered wheels by multiplying the steering wheel operation angle by a conversion coefficient, and sets the motor to obtain the determined steering angle of the steered wheels. Drive control, wherein the handle sensitivity changing means changes the conversion coefficient according to an input operation unit for inputting a handle sensitivity change signal from the outside and a handle sensitivity change signal externally input from the input operation unit. The cargo handling vehicle according to claim 1, further comprising: a coefficient changing unit that changes. 3. The cargo handling vehicle according to claim 2, further comprising display means for displaying an image of a change state of the conversion coefficient by the coefficient changing section according to an operation of the handle sensitivity changing means.