JP2000053398A - Reach control device for reach forklift - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reach control device capable of making cargo-handling work of a reach forklift more stable than a conventional way. SOLUTION: This device is a reach control device 1 of a reach forklift. The device 1 has a reach cylinder 14 making a mast reach, an oil control valve 13 adjusting hydraulic fluid amount to be delivered to the reach cylinder 14 according to an operation of a lever 131, a flow rate regulating valve 2 provided on an oil path 95 between the oil control valve 13 and the reach cylinder 14, a speed detection means 3 detecting speed of the reach forklift, a load detection means 4 detecting loaded load of a fork and a controller 5 calculating restriction amount of the flow rate regulating valve 2 by using speed data from the speed detection means 3 and load data from the load detection means 4 and controlling the valve 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reach control device having improved stability of cargo handling work in a reach forklift and a reach forklift having the same.

[0002]

2. Description of the Related Art A reach forklift is configured to move (reach) a mast provided with a liftable fork in a longitudinal direction. The reach control device 9 for controlling the reach operation is constituted by a hydraulic circuit as shown in FIG. As shown in the drawing, the conventional reach control device 9 is provided with a reach cylinder 94 for performing a reach operation of a mast in a hydraulic circuit including an oil tank 91, an oil pump 92, and an oil control valve 93.

By operating a lever 931 of an oil control valve 93, the reach cylinder 94 adjusts the amount of oil in oil passages 95 and 96 to control the advance / retreat speed. Therefore, the control of the reach speed is left to the skill of the operator who operates the lever 931 of the oil control valve 93. Reference numeral 97 in FIG. 6 denotes a lift cylinder for raising and lowering the fork, and 98 denotes a tilt cylinder for tilting the fork forward or backward.

[0004]

However, the conventional reach control device 9 has the following problems. That is, in the cargo handling work in the reach forklift, the vehicle body is often run while performing the reach operation of the mast. In this case, the stability of the vehicle body and the stability of the load are reduced, and the load may fall.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a reach control device capable of more stably performing a cargo handling operation of a reach forklift.

[0006]

According to a first aspect of the present invention, there is provided a reach control device for a reach forklift, wherein a mast having a fork capable of moving up and down is provided so as to be able to reach in a longitudinal direction.
A reach cylinder for reaching the mast, an oil control valve for adjusting the amount of hydraulic oil sent to the reach cylinder in accordance with a lever operation, and a flow regulating valve provided in an oil passage between the oil control valve and the reach cylinder And vehicle speed detecting means for detecting the vehicle speed of the reach forklift, load detecting means for detecting the load of the fork, and vehicle speed data from the vehicle speed detecting means and load data from the load detecting means. A reach controller for calculating and controlling the throttle amount of the flow control valve.

The most remarkable point of the present invention is that the flow control valve, the vehicle speed detecting means, the load detecting means, and the controller are provided, and the throttle valve of the flow control valve is calculated by using the vehicle speed data and the load data. That is, the amount is controlled.

As the vehicle speed detecting means, for example, means for measuring the number of revolutions or current consumption of a drive motor, means for measuring the number of revolutions of a drive tire or road tire, and various other means can be used. The load detecting means may be of a type that detects the load stepwise in two or more stages or a type that detects the load linearly. In particular,
For example, there are means for measuring the load applied to the fork using a strain gauge, means for measuring the pressure in the lift cylinder using a pressure sensor, means for measuring the displacement of the root of a floating lift chain, and various other means. .

The controller calculates the throttle amount of the flow control valve using the vehicle speed data and the load data as described above, and controls the flow control valve in accordance with the calculation result. In this case, the vehicle speed data can be converted into acceleration data based on the rate of change and the like, as described later. Further, the vehicle speed data, the acceleration data, and the load data can be used together.

The above calculation may be performed by using a matrix, as will be described later, by using a function representing the relationship between vehicle speed data (acceleration data) and load data and the optimum throttle amount of the flow control valve, and other methods. Various methods using the vehicle speed data and the load data in combination can be adopted.

Next, the operation of the present invention will be described. In the present invention, the flow control valve is provided in an oil passage between the oil control valve and the reach cylinder.
As described above, the throttle amount of the flow control valve is controlled to an optimum amount by the controller according to the vehicle speed data and the load data. Therefore, in the reach control device, the throttle amount of the flow control valve is appropriately controlled when the load changes, when the vehicle speed changes, or when the load and the vehicle speed change.

When the flow control valve is throttled, the amount of oil sent to the reach cylinder is regulated by the throttle amount of the flow control valve regardless of the degree of opening of the oil control valve. Therefore, even when the oil control valve is widely opened, if the conditions of the vehicle speed and the load are severe, the amount of oil to the reach cylinder is regulated to a small amount by the flow rate adjusting valve. Then, due to the decrease in the oil amount, the expansion / contraction speed of the reach cylinder, that is, the reach speed is controlled to a safe low speed state regardless of the opening degree of the oil control valve.

As described above, according to the present invention, the reach speed can always be regulated to a safe speed according to the vehicle speed of the reach forklift and the load on the fork, regardless of the degree of opening of the oil control valve. Therefore, even if the skill level of the operator, which is conventionally required for operating the oil control valve, is insufficient, the cargo handling operation can be stably performed.

Next, as in the second aspect of the invention, in the calculation in the controller, acceleration data is calculated from the vehicle speed data, and the throttle amount of the flow control valve is calculated from the acceleration data and the load data. Is preferred.
In this case, the reach speed when the inertia force acting on the load increases during acceleration or deceleration of the vehicle body can be reliably limited, and the stability of the cargo handling operation can be further improved.

According to a third aspect of the present invention, the controller determines in advance the throttle amount of the flow control valve in each area of a matrix in which the acceleration data and the load data are vertically and horizontally. It is preferable that the matrix is used to determine the throttle amount of the flow control valve. In this case, the calculation of the throttle amount of the flow control valve can be easily performed.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A reach control device for a reach forklift according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 2, the reach control device 1 of the present embodiment is a reach control device of a reach forklift 8 provided with a mast 82 provided with a fork 81 capable of ascending and descending so as to be able to reach in the front-rear direction.

As shown in FIG. 1, the reach control device 1 includes a reach cylinder 14 for reaching the mast 81.
And the amount of hydraulic oil sent to the reach cylinder 14
Oil control valve 1 adjusted according to the operation of 1
And 3. The reach control device 1 includes a flow rate adjusting valve 2 provided in an oil passage 95 between the oil control valve 13 and the reach cylinder 14, a vehicle speed detecting means 3 for detecting a vehicle speed of the reach forklift 8, and a fork 81. And a controller for calculating and controlling the throttle amount of the flow control valve 2 using the vehicle speed data from the vehicle speed detector 3 and the load data from the load detector 4 using the load detecting means 4 for detecting the load of the vehicle. And 5.

The vehicle speed detecting means 3 is configured to continuously output constantly changing vehicle speed data by using a vehicle speed sensor which reads the number of revolutions of the drive motor and thus the vehicle speed by measuring the current consumption of the drive motor. I have. This vehicle speed data is converted into acceleration data by the function of the controller 5 described later.

The load detecting means 4 has a structure in which the load is read from the output value of a strain gauge attached to the fork mounting portion, and as shown in FIG. To two-stage load data K1,
It is configured to output as K2.

The output states of these data are shown in FIGS.
It is shown in (c). FIG. 3A is an example of vehicle speed data in which the horizontal axis represents time (seconds) and the vertical axis represents vehicle speed data (m / second). FIG. 3B shows an example in which the vehicle speed data is converted into acceleration data, in which the horizontal axis represents time (seconds) and the vertical axis represents acceleration data (m / second ² ). Also, FIG.
(C) shows the actual load (kg) on the horizontal axis and the output value of the load data on the vertical axis.

Further, the controller 5 in the present embodiment
Is obtained by first converting the vehicle speed data into acceleration data as described above, and then, as shown in FIG.
The throttle amount of the flow control valve 2 in 1 to M4 is determined in advance, and the throttle amount of the flow control valve 2 is determined using the matrix M.

The acceleration data in this example is calculated as plus (+) when the direction is the same as the direction of the mast reach operation, and as minus (-) when the direction is opposite. That is, only the acceleration data that increases the inertial force acting on the load is considered. In the matrix M, the acceleration is divided into regions where the acceleration is equal to or larger than A (plus value) and smaller than A.

The calculation process in the controller 5 will be described with reference to the flowchart shown in FIG. First, in step S11, the vehicle speed data and the load data are taken into the controller, and the vehicle speed data is converted into acceleration data to calculate which of the regions M1 to M4. Next, it is determined which of the areas M1 to M4 is calculated in steps S12 to S14, and the throttle amount of the flow control valve is controlled in steps S15 to S18 according to the result.

Therefore, in the reach control device 1, when both the load data and the acceleration data fall in the low region M1, the flow control valve is kept fully open (step 15), and the load data is larger than M1. In the case of the area M2, the flow control valve is throttled by about 25% (step 16).
In the area M3 where the acceleration data is larger than 1, the flow control valve is throttled down to about 50% (step 17). In the area M4 where the load data and acceleration data are very large, the flow control valve is reduced to about 75%. It is controlled to be squeezed (step S18).

Next, the operation of this embodiment will be described. In the reach control device 1 according to the present embodiment, the above-described flow control valve 2 is provided in an oil passage 16 between the oil control valve 13 and the reach cylinder 14. As described above, the throttle amount of the flow control valve 2 is controlled by the controller 5 according to the vehicle speed data and the load data to the optimal amount of the four stages.

When the flow control valve 2 is throttled,
The amount of oil sent to the reach cylinder 14 is regulated by the throttle amount of the flow control valve 2 irrespective of the degree of opening of the oil control valve 13. Therefore, even when the oil control valve 13 is widely opened, if the vehicle speed and load conditions are severe, the reach cylinder 14
The amount of oil supplied to is regulated to a small amount by the flow control valve 2. Then, due to the decrease in the oil amount, regardless of the opening degree of the oil control valve 13, the reach cylinder 14
The expansion / contraction speed, that is, the reach speed is controlled to a safe low speed state.

Further, the matrix M used in the calculation of the controller 5 is based on the area M in consideration of the inertia force.
1 to M4 are determined. Therefore, it is possible to easily control the throttle amount of the flow control valve 2 according to the inertia force of the load. Therefore, in the reach control device 1, not only when the load changes but also when the vehicle speed changes, these data are used in combination to reduce the flow rate to the throttle amount corresponding to the inertia force of the load. The control valve 2 can be controlled.

As described above, in the present embodiment, the reach speed is always regulated to a safe speed in accordance with the vehicle speed of the reach forklift and the load on the fork 81, regardless of the opening of the oil control valve 13. it can. Therefore, even if the skill level of the operator who is conventionally required to operate the oil control valve 13 is insufficient, the cargo handling operation can be stably performed.

In the present embodiment, the above calculation is performed using the matrix M. However, the calculation is performed using a function representing the relationship between the vehicle speed data and the load data and the optimal throttle amount of the flow control valve, and other methods. Various methods using the vehicle speed data and the load data in combination can be adopted.

Further, in the present embodiment, the area of the matrix is divided into four, but it is possible to reduce it to two or increase it to five or more. In the case where the number is reduced to two, as shown in FIG. 5, the selection can be made by either selecting the flow control valve or by fully opening it, and the configuration of the controller and the like can be simplified.

Second Embodiment As shown in FIG. 5, in this embodiment, the load data and the acceleration data are determined in two stages without using the matrix M in the first embodiment, and the flow control valve is throttled. Alternatively, this is a simplified example in which a two-stage control of whether to fully open is performed.

That is, in the controller of this embodiment, as shown in FIG. 5, first, in step S1, it is determined whether or not the load data is equal to or larger than a reference value. If the load data is less than the reference value, the flow control valve is kept fully open in step S4. On the other hand, if the load data is equal to or greater than the reference value, it is determined in step S2 whether the acceleration / deceleration data is equal to or greater than the reference value.

If the acceleration / deceleration data is less than the reference value, the flow control valve is kept fully open in step S4.
On the other hand, when the acceleration / deceleration data is equal to or larger than the reference value, the flow control valve is reduced to, for example, 50%. As a result, when the load and acceleration / deceleration are both large and the inertia force to the load is large, the amount of oil sent to the reach cylinder by the flow control valve is surely reduced, and the reach speed is maintained at a safe low speed state. .

In this embodiment, since the flow control valve is controlled in two stages, that is, whether the flow control valve is throttled or left fully open, the opening / closing mechanism of the flow control valve can be simplified. Other effects are substantially the same as those of the first embodiment.

[0035]

As described above, according to the present invention, it is possible to provide a reach control device capable of more stably performing a cargo handling operation of a reach forklift than before.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram illustrating a configuration of a reach control device according to a first embodiment.

FIG. 2 is an explanatory diagram showing a reach forklift according to the first embodiment.

FIG. 3 is an explanatory diagram showing (a) output of vehicle speed data, (b) output of acceleration data, (c) output of load data, and (d) a matrix used for calculation in the first embodiment.

FIG. 4 is a flowchart showing a control flow in the first embodiment.

FIG. 5 is a flowchart illustrating a control flow according to the second embodiment.

FIG. 6 is an explanatory diagram showing a configuration of a reach control device in a conventional example.

[Explanation of symbols]

 1. . . 12. reach control device, . . Oil control valve, 131. . . Lever, 14. . . Reach cylinder, 2. . . Flow control valve, 3. . . 3. vehicle speed detection means; . . 4. load detecting means; . . controller,

Claims (3)

[Claims] 1. A reach control device for a reach forklift provided with a mast capable of moving a fork up and down so as to be able to reach in a front-rear direction, and a lever cylinder for reaching the mast and an amount of hydraulic oil sent to the reach cylinder. An oil control valve that adjusts according to
A flow regulating valve provided in an oil passage between the oil control valve and the reach cylinder, a vehicle speed detecting means for detecting a vehicle speed of the reach forklift, a load detecting means for detecting a load of the fork; A reach control device for a reach forklift, comprising: a controller that calculates and controls the throttle amount of the flow rate control valve using vehicle speed data from a detection unit and load data from the load detection unit. 2. The reach according to claim 1, wherein the calculation in the controller calculates acceleration data from the vehicle speed data, and calculates a throttle amount of the flow control valve from the acceleration data and the load data. Forklift reach control device. 3. The controller according to claim 2, wherein the controller determines in advance the throttle amount of the flow control valve in each area of a matrix in which the acceleration data and the load data are vertically and horizontally, and uses the matrix. A reach control device for a reach forklift, wherein the amount of throttle of the flow rate regulating valve is determined.