JP3552358B2 - Tilt mechanism of cargo handling vehicle - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tilt mechanism for tilting a fork mounted on a cargo handling vehicle such as a forklift.
[0002]
[Prior art]
As a conventional tilt mechanism of a cargo handling vehicle, when an operator operates a tilt lever, a proportional control valve mechanically connected to the lever via a link according to the angle of the lever (hereinafter, referred to as a lever angle) is used. There are known ones that are operated to change the tilting speed of the fork, or ones in which an electronically controlled proportional control valve is operated in the same manner according to the lever angle. FIG. 5 shows a tilt mechanism of a type in which the proportional control valve is electronically controlled (hereinafter simply referred to as an electronically controlled tilt mechanism). The tilt mechanism 51 is an input means for operating the fork F. A tilt lever 52, a lever angle sensor 53 for detecting a lever angle of the tilt lever 52, a tilt cylinder 54 which is a driving source of the tilt of the fork F, a hydraulic source 55 for operating the tilt cylinder 54, a hydraulic source 55 and a tilt An electromagnetic proportional control valve (hereinafter, simply referred to as a control valve) 56 provided in a pipe connecting the cylinder 54 to adjust the amount of oil flowing from the hydraulic source 55 to the tilt cylinder 54, and a control valve 56 corresponding to the detected lever angle And a controller 57 that calculates the opening of the control valve and controls the control valve 56. FIG. 6 is a flowchart showing the operation of the tilt mechanism 51. When the operator operates the tilt lever 52 (step 52), the lever angle of the operated tilt lever 52 is detected by the lever angle sensor 53. The detected signal is transmitted to the controller 57 (step 53). Then, the opening (P ₁ ) of the control valve 56 corresponding to the transmitted signal is calculated (step 54), and the control valve 56 is operated with the calculated opening (P ₁ ) (step 55). The fork F tilts at a constant speed (step 56).
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional tilt mechanism, the degree of inclination of the fork (that is, the tilt angle) is not considered, and even if the fork is tilted forward, the opening of the control valve is determined only by the lever angle. If the lever angle is large, the fork moves forward at a high speed, and there is a possibility that the cargo may move.
[0004]
An object of the present invention is to solve the above-mentioned problems and to provide a tilting mechanism of a cargo-handling vehicle excellent in workability that does not cause the movement of a load.
[0005]
[Means for Solving the Problems]
In the first aspect of the present invention, a tilt lever for operating a fork, a tilt cylinder serving as a driving source for tilting the fork, a hydraulic source for operating the tilt cylinder, A control valve provided in a pipe connecting a power source and the tilt cylinder to adjust an amount of oil flowing from a hydraulic source to the tilt cylinder, a lever angle sensor capable of detecting a lever angle of the tilt lever, and a tilt of the fork. A tilt angle sensor capable of detecting an angle, and a controller that calculates an opening of the control valve based on the detected lever angle and the detected tilt angle, and controls an opening of the control valve. by manipulating the controls the opening degree of the control valve in response to the lever angle of the tilt lever, a tilt mechanism of the cargo handling vehicle for adjusting the tilting speed of the fork, The serial controller, during operation of the at least anteversion direction of the fork, prior to calculate the opening P ₁ of the control valve on the basis of the lever angle detected by the lever angle sensor, the forks from the horizontal tilt-side when in, the control valve opening P ₂ which is a set maximum value lower than when it is in the rear-tilt-side than the horizontal, calculated on the basis of the tilt angle detected by the tilt angle sensor, wherein by comparing the opening degree P ₁ and opening P _2, when a P ₁ ≦ P _2, while the opening degree of the control valve and P _1, if a P _1> P _2, the control valve the opening in performing control to P _2.
[0006]
According to a second aspect of the present invention, in the first aspect, the tilt angle of the fork is within a range having a certain angle from the horizontal of the fork to each of the forward tilt side and the rear tilt side, and the tilt angle of the fork rearward from the neutral position. And a forward leaning position which is on the forward leaning side of the neutral position, and the maximum value of the opening degree of the control valve is lower in the forward leaning position than in the backward leaning position. In the position, the control is continuously increased from the forward tilt position to the rear tilt position.
[0007]
According to a third aspect of the present invention, in the second aspect, the constant angle can be changed and adjusted.
[0009]
[Action]
According to the tilt mechanism of the cargo handling vehicle of the first invention, the maximum value of the opening degree of the control valve that can be adjusted by the tilt lever is larger when the fork is tilted forward than horizontal than when it is tilted backward from horizontal. Lower. Therefore, when the fork is on the forward tilt side from the horizontal, the tilt speed does not accidentally increase. When the opening of the control valve satisfies P ₁ > P ₂ when the fork is tilted forward , the fork is automatically limited to the tilting speed determined by the opening P ₂ of the control valve. Can be effectively prevented from falling.
[0010]
According to the tilt mechanism of the cargo handling vehicle of the second invention, the maximum value of the opening degree of the control valve is lower when the fork is in the forward tilt position than when the fork is in the rear tilt position. Therefore, when the fork is at the forward tilt position, the tilt speed does not accidentally increase. When the fork is at the neutral position, the maximum value of the opening of the control valve continuously increases from the forward tilt position to the rear tilt position. Therefore, when the fork is in the neutral position, the tilting speed does not accidentally increase, and a necessary and sufficient tilting speed is obtained without impairing the workability.
[0011]
According to the tilting mechanism of the cargo handling vehicle of the third invention, the constant angle in the range of the neutral position can be changed and adjusted. Therefore, it can be set appropriately according to the cargo handling situation and the like.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing an example in which the tilt mechanism of the present invention is mounted on a battery type forklift. This tilt mechanism also controls the fork tilting speed by electronic control according to the lever angle of a tilt lever operated by an operator. To change it. The tilt mechanism 1 includes a tilt lever 2 as input means for operating the fork F, a lever angle sensor 3 for detecting a lever angle of the tilt lever 2, a tilt cylinder 4 as a driving source for tilting the fork F, and a tilt. A hydraulic source 5 for operating the cylinder 4, a control valve 6 provided on a pipe connecting the hydraulic source 5 and the tilt cylinder 4 to adjust an amount of oil flowing from the hydraulic source 5 to the tilt cylinder 4, a tilt angle of the fork F And a controller 8 that calculates the opening of the control valve 6 corresponding to the detected lever angle and tilt angle and controls the control valve 6, and the like.
[0015]
The lever angle sensor 3 is attached to the tilt lever 2, and the tilt / tilt angle sensor 7 is attached to the tilt cylinder 4. Further, power is supplied to the controller 8, the control valve 6, the lever angle sensor 3, and the tilt angle sensor 7 from a battery (not shown) built in the forklift.
[0016]
A controller 8 that controls the control valve 6 based on the detected lever angle and tilt angle converts A / D converters 10 and 10 that convert signals from the CPU 9, the lever angle sensor 3 and the tilt angle sensor 7 to transmit to the CPU 9, It comprises a ROM 11, a RAM 12, a control valve drive circuit 13 for transmitting commands from the CPU 9 to the control valve 6, and the like.
[0017]
ROM 11 stores maps M1 and M2 shown in FIGS. 2 and 3, respectively. Map M1 represents a lever angle detected, the relationship between the opening P ₁ of the control valve 6 which is determined correspondingly. That is, when the tilt lever 2 is operated, the opening P ₁ of the control valve 6 in accordance with the lever angle detected by the lever angle sensor 3 is determined from the map M1. Also, the map M2 represents a relationship between the maximum value P ₂ of the opening of the adjustable control valve by the tilt angle and the tilt lever 2 forks F in the case where the fork F is tilted before tilting direction. Further, the tilt angle of the fork F is divided into three positions: a neutral position, a backward inclined position, and a forward inclined position. The neutral position means that the fork is within a range of a fixed angle from the horizontal (O °) to both the forward and backward tilt directions (in this embodiment, both directions are 2 ° each). It means that it is in a range leaning backward from the neutral position, and that the forward leaning position is in a range leaning forward from the neutral position.
[0018]
That is, the opening of the control valve 6 when the fork F is tilted backward is determined only by the map M1. On the other hand, the opening degree of the control valve 6 when the fork F tilts in the forward tilt direction is determined by using both maps M1 and M2. First, the same, the opening P ₁ of the control valve 6 is calculated by the map M1. Then the maximum value P ₂ of the opening of the adjustable control valve 6 is calculated by the map M2, while the opening P ₁ is tilted fork F is controlled according to P ₁ does not exceed the P _2, P ₁ There are controlled according to _{P 2} if beyond _{P 2.} However, the maximum value P ₂ in the map M2 is the lever angle of the map M1 when the fork F is in the rearward tilting position coincides with the opening P ₁ at the maximum, the fork F is inclined forward direction even when tilted, without when the fork F is in the rearward tilting position can be no said opening P ₁ exceeds the maximum value P _2, therefore, substantially fork F is tilted backward direction at this time Similarly to the case where the fork F is tilted, the tilt of the fork F is controlled only by the map M1.
[0019]
Since the fork F is the the maximum value P ₂ when the forward lean position, are above set lower than the maximum value P ₂ when the rearward tilting position, when the forks F is before tilting position, the lever angle never opening degree of the control valve exceeds P ₂ no matter how large (provided that when tilting the fork F is the forward inclination direction only).
[0020]
When the fork F is tilted in the forward leaning direction when the fork F is in the neutral position, the load is not as easily shifted as in the forward leaning position. Therefore, it becomes possible to thereby suppress the P ₂ than necessary when the maximum value P ₂ will be the same as before傾時, rather would impairing workability. Also, rather loading cargo shock when the rapidly changing P ₂ is generated is liable deviation. Therefore, as shown in the map M2, the neutral position, is continuously increased toward the rearward tilting position P ₂ from the forward tilting position. Incidentally, in this embodiment, although the change in the P ₂ at the neutral position linearly, may be changed in a curved shape or the like in accordance with the working conditions.
[0021]
Hereinafter, the operation of the tilt mechanism 1 will be described with reference to the flowchart shown in FIG.
[0022]
First, after each setting is initialized in step 1 after the start, when the operator operates the tilt lever 2 in step 2, in step 3 the lever angle of the operated tilt lever 2 is determined by a lever angle sensor. 3 and the signal is transmitted to the controller 8. In step 4, the opening P ₁ of the control valve 6 in accordance with the lever angle is calculated.
[0023]
In the following step 5, it is determined from the lever angle detected in step 3 whether or not the tilt operation to be performed is in the forward tilt direction. If it is determined that the tilt direction is the forward tilt direction, the tilt angle of the fork F is detected by the tilt angle sensor 7 in step 6 and is stored in the ROM 11 in the next step 7 based on the tilt angle obtained in step 6. maximum value P ₂ is calculated for adjustable opening degree of the control valve 6 from the map M2 has. In step 8, the maximum value P ₂ of the opening obtained in the opening P ₁ and step 7 obtained in Step 4 are compared, the control valve 6 at P ₁ ≦ P ₂ If step 9 is opening P ₁ and the fork F tilts accordingly. If P ₁ > P ₂ , P ₂ is substituted for P ₁ in step 10, and then the process proceeds to step 9. That is, the control valve 6 is controlled such that the opening P _2, the fork F is tilted accordingly.
[0024]
On the other hand, in step 5, when the tilting operation is determined to tilted backward direction, the process proceeds to step 9, the control valve 6 is controlled such that the opening P _1, fork F is tilted accordingly.
[0025]
Note that the above control contents from step 2 to step 9 are repeated every very short control unit time.
[0026]
As mentioned above, the maximum value of the degree of opening of the control valve when the tilt operation in step 5 is tilted backward direction without being restricted, it is controlled by opening P ₁ according always map M1. On the other hand, when the tilt operation is in the forward tilt direction, the opening of the control valve is P ₁ ≦ P ₂ in step 8, that is, the opening P _{1 according} to the map M ₁ exceeds the maximum value P _{2 of the} opening according to the map M _2. when there is the same, always controlled by opening P _1. Also, _P 1> _{P 2} in step 8, that is, when the opening _{P 1} by the map M1 is greater than the maximum value _{P 2} of the opening by the map M2 is controlled by opening _{P 2.} Since the fork F is inevitably P ₁ ≦ P ₂ when the rearward tilting position, the rearward tilting position will be determined by indirectly Step 8.
[0027]
The tilt mechanism is configured as described above, and when the fork F is tilted forward and the fork F is in the neutral / forward tilt state and the control valve opening degree is P ₁ > P ₂ , the tilt mechanism is controlled. since is automatically limited to the inclining speed determined by the opening P ₂ of the valve, it is possible to effectively prevent the falling of the load.
[0028]
The structure of the tilt mechanism according to the present invention is not limited to the embodiment described above. The structure of the tilt lever, the installation position of the lever angle sensor / tilt angle sensor, the lever The relational expression of the angle-control valve opening degree / opening basic pattern can be changed. For example, a plurality of button switches for changing the tilting speed can be provided instead of the tilt lever.
[0029]
In this embodiment, the opening of the control valve is not limited when the tilt operation is in the backward tilt direction. This is because, as described above, the load is relatively less likely to shift than in the case of the forward tilt direction. However, when the shape of the load lacks stability, the load is likely to shift even when the tilt operation is in the backward tilt direction. Therefore, the opening degree of the control valve may be limited in accordance with these conditions even when the tilt operation is in the backward tilt direction, as in the forward tilt direction.
[0030]
Similarly, in this embodiment, the opening of the control valve is not limited when the fork F is in the backward tilt position even when the tilt operation is in the forward tilt direction. This is because it is difficult to shift the target. Therefore, this case may be limited in accordance with various conditions.
[0031]
Further, in the present embodiment, the range of the neutral position of the fork F is set to ± 2 °, but may be set to another range, or the range itself may be set variably. Alternatively, the neutral position may be eliminated, and only the fork F may be divided into two, that is, the forward inclined position and the backward inclined position with the horizontal of the fork F. Of course, in this case, the maximum value P ₂ of the opening of the adjustable control valve 6 is set low earlier tilting position.
[0032]
Further, the maximum value P ₂ in the map M2 may be made to increase all continuously toward the rearward tilting position from the forward inclination position.
[0033]
Further, instead of controlling the maximum value of the opening of the control valve 6 by the map M2, a plurality of maps in which the inclination of the opening of the control valve 6 is changed according to the lever angle are prepared in addition to the map M1. The selection may be made automatically according to the position of the fork F.
[0034]
On the other hand, the tilting speed may be controlled by different methods depending on whether the cargo handling vehicle is traveling or not. In addition, a throttle is installed together with the control valve in the pipe connecting the tilt cylinder and the hydraulic pressure source. When the lever angle increases, the opening of the control valve simply increases, and the tilt angle is in a neutral / forward tilt state. It is also possible to configure so that the throttle is controlled only when it is determined that the amount of oil sent from the hydraulic pressure source to the tilt cylinder is small (this method is applicable to tilt mechanisms other than the electronically controlled tilt mechanism). Can also be adopted). Further, the tilt mechanism of the present invention does not always limit the tilting speed of the fork when the fork in the forward leaning operation is in the neutral / forward leaning state, and the fork in the forward leaning operation is in the neutral / forward leaning state. It is also possible to provide a control mode switching switch so as to limit the tilting speed of the fork only when necessary, even if With such a configuration, there is an advantage that work efficiency can be improved according to the work content. Note that the tilt mechanism of the present invention can be mounted on any cargo handling vehicle other than a battery-powered forklift.
[0035]
【The invention's effect】
According to the tilt mechanism of the present invention, when the fork is tilted forward at least when the fork is tilted forward , the opening of the control valve and thus the maximum value of the tilting speed of the fork are automatically limited. Fall can be effectively prevented. Further, the tilt mechanism of the present invention can be easily obtained by simply mounting a tilt angle sensor at an appropriate position and changing a program written in a ROM without largely modifying a conventional electronically controlled tilt mechanism. There are also benefits.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a tilt mechanism according to an embodiment.
FIG. 2 is an explanatory diagram showing a relationship between a lever angle and an opening degree of a control valve.
FIG. 3 is an explanatory diagram showing an opening basic pattern.
FIG. 4 is a flowchart showing an operation content of a tilt mechanism of the embodiment.
FIG. 5 is a block diagram showing a conventional tilt mechanism.
FIG. 6 is a flowchart showing the operation of a conventional tilt mechanism.
[Explanation of symbols]
1 tilt mechanism, 2 tilt lever, 3 lever angle sensor, 4 tilt cylinder, 5 hydraulic pressure source, 6 control valve, 7 tilt angle sensor, 8 controller, 9 CPU, 10 A / D converter, 11 ROM, 12 RAM, 13 control valve drive circuit, 51 tilt mechanism, 52 tilt lever, 53 lever angle sensor, 54 ··· Tilt cylinder, 55 ·· Hydraulic power source, 56 ·· Control valve, 57 ··· Controller, F ·· Fork.

Claims (3)

A tilt lever for operating the fork, a tilt cylinder that is a drive source for tilting the fork, a hydraulic source for operating the tilt cylinder, and a pipe that connects the hydraulic source and the tilt cylinder are provided. A control valve for adjusting an amount of oil flowing from a hydraulic pressure source to a tilt cylinder, a lever angle sensor capable of detecting a lever angle of the tilt lever, a tilt angle sensor capable of detecting a tilt angle of the fork, and a detected lever Calculating a degree of opening of the control valve based on the angle and the tilt angle, and a controller for controlling the degree of opening of the control valve, by operating the tilt lever, according to the lever angle of the tilt lever A tilt mechanism of a cargo handling vehicle that controls an opening degree of a control valve to adjust a tilting speed of a fork,
In the controller, during operation of the at least anteversion direction of the fork, prior to calculate the opening P ₁ of the control valve on the basis of the lever angle detected by the lever angle sensor, the forks from the horizontal tilt-side when in, the control valve opening P ₂ which is a set maximum value lower than when it is in the rear-tilt-side than the horizontal, calculated on the basis of the tilt angle detected by the tilt angle sensor, wherein by comparing the opening degree P ₁ and opening P _2,
When P ₁ ≦ P ₂ , the opening of the control valve is set to P ₁ ,
P _1> when it is P _2, the tilt mechanism of the cargo handling vehicle the opening of the control valve and performing control to P _2. The tilt angle of the fork, the neutral position within a range having a certain angle from the horizontal of the fork to the forward inclined side and the backward inclined side, respectively, a rearward inclined position which is a backward inclined side from the neutral position, and a forward inclined side from the neutral position. Divided into a certain forward leaning position,
At the same time, the maximum value of the opening degree of the control valve is controlled to be lower in the forward tilt position than in the rearward tilt position, and to be continuously increased in the neutral position from the forward tilt position to the rearward tilt position. The tilt mechanism for a cargo handling vehicle according to claim 1, wherein The tilt mechanism according to claim 2, wherein the fixed angle can be changed and adjusted.

Images