JPH0715478U - Forklift driving mode switching device - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a traveling mode switching device capable of easily selecting a traveling mode without worrying about a steering angle of a drive wheel. [Structure] When the driving mode is switched, the present steering angle of the drive wheel is compared with the limit steering angle, and when it is determined that the steering angle of the drive wheel exceeds the range of the limit steering angle, the drive wheel is driven by the power steering motor. And a control unit for controlling the switching means so as to disconnect the linkage between the steering wheel and the drive wheel while steering the steering angle within the range of the limit steering angle,
It is possible to switch the driving mode without requiring skilled driving skill.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an improved device for a forklift truck capable of switching and controlling a plurality of driving modes so that a driver can easily select a desired driving mode.

[0002]

[Prior art]

 In recent years, as represented by Japanese Patent Application No. 3-306767 previously proposed by the present applicant, the forklift is improved and various traveling modes (hereinafter, referred to as "traveling mode" or simply "mode") It has been proposed that it is possible to do.

As shown in FIG. 7, the forklift 1 has a drive wheel 4 steered by a steering wheel 3, left and right load wheels 5, 6 steerable via steering motors 11, 12 and a transmission 10. Further, the potentiometers 13 and 14 capable of detecting the respective steering angles, the potentiometer 18 capable of detecting the steering angles of the drive wheels, and the like are mounted. Although not shown, the torque applied to the steering wheel is obtained by assist torque from the power steering motor to steer the drive wheel 4.

However, the forklift 1 uses the steering angle of the drive wheel 4 as a command signal and steers the left and right road wheels based on this signal. However, the switches A, B, C of the drive mode selection device 15 are operated by the forklift 1. By operating it, you can run in the desired driving mode.

For example, when the switch A is selected, the in-phase mode is set, and as shown in FIG. 6A, the steering angle of the drive wheel 4 and the steering angles θ D, θ L, and θ R of the left and right road wheels 5 and 6 are both set. Equal control is performed to enable traveling without changing the attitude of the forklift.

Further, when the switch B is selected, a spin turn mode is set, and as shown in FIG. 6B, the turning center point can be matched with the center of the forklift vehicle body at the maximum turning angle of the steering wheel.

Further, when the switch C is selected, the so-called anti-phase mode is set, and the axis in which the turning center is continuous is controlled so that it can be positioned below the axis connecting the left and right road wheels, and is configured to make a small turn. There is.

By the way, each of the above-mentioned traveling modes has a restriction due to the steering angle of the drive wheel 4. That is, the left and right steering ends of the drive wheel 4 are mechanically limited, and the drive wheel 4 cannot be continuously steered by 360 degrees. Also, for the convenience of arithmetic processing of a control device (not shown), a certain driving mode is set. In order to execute the above, it may be necessary to limit the steering angle of the drive wheel 4 within a certain angle range.

As an example, as shown in FIG. 6C, in the anti-phase mode, the locus of the turning center point is not continuous, so that when the steering angle of the drive wheel 4 is in the range of α in the drawing, The reverse phase mode cannot be selected by pressing switch C.

[0010]

[Problems to be solved by the device]

 However, it is difficult for the driver of the forklift 1 to know in which direction the drive wheel 4 is currently facing, and the steering angle limit angle of the drive wheel 4 in each traveling mode. On the other hand, there is a problem that even if you are familiar with it, you need driving skills and are prone to fatigue and poor workability.

The present invention has been devised to solve such a problem, and an object thereof is a traveling mode in which a traveling mode can be easily selected without worrying about a steering angle of a drive wheel. It is to provide a switching device.

[0012]

[Means for Solving the Problems]

 The present invention is a driving mode switching device used for a forklift capable of switching a plurality of driving modes, and can be steered by a mode selection switch capable of selectively inputting any driving mode and a steering wheel or a power steering motor. A drive wheel, storage means for storing a steering limit angle of the drive wheel in each of the traveling modes, steering angle detection means for detecting a current steering angle of the drive wheel, the drive wheel, and a power steering motor The steering angle of the drive wheel at present is compared with the limit steering angle at the time of switching the driving mode. To the extent that the drive wheel steering angle exceeds the limit steering angle range, A ring motor steers the steering angle of the drive wheel within a range of the limit angle and, during the steering, controls the switching means so as to disconnect the connection between the steering wheel and the drive wheel. It is a running mode switching device.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings, in which the same parts as those in the prior art are designated by the same reference numerals. FIG. 1 shows a block diagram of the present invention, which includes an operation display section 43, a potentiometer 18 capable of detecting the actual steering angle of the drive wheel 4, a CPU 27 which performs arithmetic processing based on these input signals, and each traveling mode. It is composed of a limit steering angle of the drive wheel 4 in the mode and a ROM 29 which stores various processing procedures.

As shown in FIG. 2, the operation display section 43 includes mode selection switches 21, 22, 23 corresponding to the respective traveling modes, and display sections 24, 25 capable of displaying completion during the transition of the traveling modes. Composed of and.

In addition to the processing procedure of the CPU 27, which will be described later, the ROM 29 stores the range of the steering angle of the drive wheel 4 in which each traveling mode can be executed, that is, the limit steering angle.

In FIG. 1, reference numeral 28 is a RAM that is a working memory, and reference numerals 30 and 31 are input / output interfaces.

As shown in FIG. 5, the drive wheel 4 is configured such that a steering torque applied to the handle 3 is transmitted from the sprocket 33 to the sprocket 34 via the chain C, and the input shaft and the steering wheel fixed to the sprocket 34 are fixed. It is transmitted to the output shaft, the universal joint 36, the drive shaft, and the drive gear 39 via the torque detector 35 to rotate the swing gear 40.

A swivel gear case 42 that pivotally supports the drive wheel 4 is fixed to the swivel gear 40. Further, the steering torque detector 35 electrically detects a relative twist between the input shaft and the output shaft as a steering torque signal, and accordingly drives the power steering motor 37 to rotate and a gear having a speed reduction mechanism. The assist torque is applied to the drive shaft gear 39 via the case 38, and the steering torque is reduced.

The turning gear 40 is meshed with a detection gear of a steering angle detector 18 such as a potentiometer, and is configured to detect the steering angle of the drive wheel 4.

In addition, in this example, an electromagnetic clutch 43 is provided as a means for detachably disconnecting the linkage between the handle 3 and the drive wheel 4. The electromagnetic clutch 43 is a known one that can engage and disengage the upper shaft 44 and the lower shaft 45 of the steering shaft 46.

[0021]

[Action]

 The operation of the present invention configured as described above will be described with reference to the flowchart shown in FIG.

First, when the driver of the forklift truck 1 turns on an arbitrary mode selection switch to switch the traveling mode, it is judged whether or not the traveling mode is the one currently selected (S1). If so, the running mode is executed as it is.

When the selected traveling mode is different from the previous one (N in S1), the traveling of the forklift is stopped (S2), and the limit steering angles θDR and θDL of the drive wheels in the traveling mode are stored in the RAM 28 from the ROM 29. (S3). Here, θDR is an angle at the right end of the limit steering angle, and θDL is an angle at the left end thereof, as schematically shown in FIG.

Further, the electromagnetic clutch 43 is turned off (S4), and the upper shaft 44 and the lower shaft 45 of the steering shaft 46 are separated.

Next, the current actual steering angle θD of the drive wheel 4 is read into the RAM 28 (S5), and the actual steering angle θD is compared with the right end angle θDR of the limit steering angle (S6).

As shown in FIG. 4, when the actual steering angle θD of the drive wheel 4 is larger than the right-end angle θDR of the limit steering angle (Y in S6), the traveling mode may be changed as it is. Can not. Therefore, in this case, a motor control signal is output to the power steering motor 37 so as to steer the drive wheel 4 in a direction to reduce the steering angle θD (S13).

Similarly, although the step S6 is cleared, if the actual steering angle θD is smaller than the left end angle θDL of the limit steering angle (Y in S7), the traveling mode is changed in step S7. Therefore, a motor control signal is output to the power steering motor 37 so as to increase θD so that the steering angle θD of the drive wheel 4 is increased (S14). With the above processing, the drive wheel 4 can be positioned within the range of the limited steering angle.

After steps S13 and S14, the procedure for releasing the restriction of the handle steering range in the previously selected traveling mode is included (S12) because the limit in the previously selected traveling mode is set. This is to deal with the case where the steering angle of the drive wheel is limited by the range of the steering angle and the steering wheel cannot be turned to shift to the next selected driving mode.

When steps S6 and S7 are cleared, the power steering motor 37 is stopped (S8) and the electromagnetic clutch 43 is put into an engaged state (S9). Since the steering angle of the drive wheel 4 can be located within the range of the limit steering angle, it is possible to shift to the selected traveling mode. After the steering range of the steering wheel is restricted within the range of the selected limit steering angle so as not to go out of the range (S10), the traveling stop is released (S11).

As a result, since the forklift does not travel until the change of the travel mode is completed, it is safe, and then the selected travel mode is executed. As described above, the handle 3 is mechanically linked to the drive wheel 4 while the drive wheel 4 is positioned within the limit steering angle range in which the traveling mode can be executed, that is, during steps S4 to S8 of the above-described flowchart. Since the steering wheel 3 is separated, the steering wheel 3 is not affected even if the drive wheel 4 is steered by the power steering motor 37, and kickback can be preferably prevented.

As a means for limiting the end of the steering angle of the drive wheel, although not shown in the figure, it is possible to mechanically move a stopper, or a power steering motor as the drive wheel approaches the limit steering angle. The assist torque may be reduced, and the limit steering angle may be limited by finally generating an assist torque equal to and opposite to the torque applied to the steering wheel. Further, during the mode switching, the display section 24 can be appropriately turned on to notify the driver, and various kinds of disconnection means other than the electromagnetic clutch can be used.

[0032]

[Effect of device]

 As a result of adopting the above-described configuration, the present invention does not require the driver to recognize the limit steering angle of the drive wheel at all, and can switch the driving mode without requiring skilled driving skill. Therefore, fatigue during driving can be reduced and workability can be improved. Also, kickback during switching of the running mode can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a plan view of an operation display unit.

FIG. 3 is a flowchart showing a processing procedure of a CPU.

FIG. 4 is a schematic diagram for explaining a limit steering angle.

FIG. 5 is a schematic diagram showing a transmission system of a handle and a drive wheel.

FIG. 6 is a schematic diagram for explaining a traveling mode.

FIG. 7 is a plan view showing an example of a forklift.

[Explanation of symbols]

 1 Forklift 3 Handle 4 Drive Wheel 5 Road Wheel 6 Road Wheel 18 Potentiometer 21 Mode Selector Switch 22 Mode Selector Switch 23 Mode Selector Switch 24 Indicator 25 Indicator 27 CPU 40 Operation Display Unit

Claims (1)

[Scope of utility model registration request] 1. A traveling mode switching device used for a forklift capable of switching a plurality of traveling modes,
A mode selection switch capable of selectively inputting an arbitrary drive mode, a drive wheel steerable by a steering wheel or a power steering motor, a storage means capable of storing a steering limit angle of the drive wheel in each drive mode, and a current drive wheel. Steering angle detection means capable of detecting the steering angle of, and a disconnection means capable of disengageably switching the linkage between the steering wheel and the drive wheel while maintaining the mechanical linkage between the drive wheel and the power steering motor, At the time of switching the traveling mode, the present steering angle of the drive wheel is compared with the limit steering angle, and when it is determined that the steering angle of the drive wheel exceeds the limit steering angle range, steering of the drive wheel by the power steering motor is performed. The steering angle within the range of the limit steering angle and during the steering, Travel mode switching device of a forklift comprising a control unit for controlling to shut off the connection between the switching means handle and drive wheel.