JPH0743208Y2 - Bulldozer blade controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a blade control device applied to a bulldozer having a pitch cylinder.

[Conventional technology]

This type of bulldozer can change the pitch angle of the blade by operating the pitch cylinder.

[Problems to be Solved by the Invention] When the blade A is raised in this bulldozer as shown by the solid line in FIG. 15, the blade angle θ of the blade A becomes smaller than that before the raising.

This change in the blade edge angle θ of the blade A brings the upper part of the blade A closer to the front guard B side. Therefore, conventionally, the lift height of the blade A is limited due to this blade edge angle change. It was happening. That is, although the lift cylinder (not shown) is in a state in which the blade A can be further lifted from the state shown in the figure, the height of the blade A is the same because the upper part of the blade A and the front guard B interfere with each other. There is an inconvenience that the height cannot be made higher than that shown in the figure.

Further, since the change in the cutting edge angle hinders the fall of the earth and sand from the blade A when the blade A is ascending, there has been a disadvantage that the earth and sand remain on the ascended blade.

An object of the present invention is to eliminate such inconvenience.

[Means for solving problems]

In order to achieve this object, in the present invention, in a blade control device for a bulldozer, which changes the blade edge angle by driving a lift cylinder and a pitch cylinder respectively, a lift cylinder stroke length for detecting the stroke length of the lift cylinder. Detecting means, a pitch cylinder stroke length detecting means for detecting the stroke length of the pitch cylinder, and a blade edge angle of the blade, so that the blade edge angle corresponds to each height position of the blade during operation of the lift cylinder, Storage means for storing a target stroke length of the pitch cylinder corresponding to the lift cylinder stroke length at each height position of the blade, and lift cylinder stroke length detected by the lift cylinder stroke length detection means during operation of the lift cylinder. Corresponding pitch A target stroke length of the cylinder is read from the storage means, this such that the target stroke length of the pitch cylinder and the detected pitch cylinder stroke length matches, are equipped and a controlling means for controlling the pitch cylinder.

[Action]

According to the above configuration, the pitch cylinder is controlled so that the blade edge angle becomes a blade edge angle corresponding to each height position of the blade during operation of the lift cylinder.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a dozer part of a bulldozer to which the present invention is applied, and FIG. 5 is a perspective view of the dozer part.

This bulldozer includes lift cylinders 2L and 2R that lift-operate the blade 1 and pitch cylinders 3L and 3R that change the pitch angle of the blade.

As shown in FIG. 3, since the lift cylinders 2L and 2R are connected to a common hydraulic passage, they are operated in synchronization with each other, so that the stroke lengths of the cylinders 2L and 2R are always equal. For the same reason, the pitch cylinders 3L, 3
The stroke length of R is also the same.

In such a bulldozer, when the lift cylinders 2L, 2R are retracted from the state shown in FIG. 4, the blade 1 is raised as shown in FIG. 6, and the pitch cylinder 3L is moved from the state shown in FIG. If 3R is extended, for example,
As shown in the figure, the blade 1 is rotated counterclockwise to change the pitch angle of the blade.

When the blade 1 is further lifted from the state shown in FIG. 6, the upper portion of the blade 1 comes into contact with the front guard 4, but as shown in FIG. 8, the pitch cylinders 3L, 3
When R is extended to set the blade edge angle θ of the blade 1 to the initial blade edge angle (90 °) shown in FIG. 4, the blade 1 is separated from the front guard 4. And blade 1
When the blade 1 is raised while operating the pitch cylinders 3L and 3R so that the blade edge angle of 1 always maintains the original blade edge angle, the blade 1 can be moved to the height shown in FIG.

FIG. 1 shows an embodiment of the blade device according to the present invention constructed on the basis of the above consideration. In the lift cylinder stroke detector 5 shown in the figure, the lift cylinders 2L, 2R
One of the stroke lengths L is detected, and the pitch cylinder stroke detector 6 uses the pitch cylinders 3L, 3
Stroke length 1 of either R is detected. The output signals of these stroke detectors 5 and 6 are input to the CPU 70 of the controller 7.

The memory 71 provided in the controller 7 stores the target stroke length 1ref of the pitch cylinders 3L, 3R determined by the stroke length L of the lift cylinders 2L, 2R.

This target stroke length 1ref is a pitch at which the blade edge angle of the blade 1 can always be maintained at the reference blade angle θ (for example, 90 °) shown in FIG. 4 regardless of changes in the stroke length L of the lift cylinders 2L and 2R. Cylinder stroke length. That is, it is the stroke length of the pitch cylinder that can correct the change in the cutting edge angle of the blade 1 due to the operation of the lift cylinders 2L, 2R.

Solenoids 8a and 8b shown in FIG. 1 actuate the pitch cylinder actuating servo valve 8 shown in FIG. 3, and when the solenoid 8a urges the valve 8 to the position A side, the pitch When the cylinders 3L and 3R are retracted and the valve 8 is urged toward the position B by the solenoid 8b, the cylinders 3L and 3R are extended.

The manual switching valve 9 shown in Fig. 3 is used for the lift cylinders 2L, 2
R is operated manually, and lever 10 is used to
When is selected, the cylinders 2L and 2R are degenerated,
When the position B is selected, the cylinders 2L and 2R are extended. Further, when the position C is selected, the cylinders 2L and 2R are freed.

FIG. 2 shows the processing procedure of the CPU 70 shown in FIG. 1, and the operation of this embodiment will be described below with reference to FIG.

The CPU 70 detects the stroke length L of the lift cylinders 2L, 2R and the stroke length 1 of the pitch cylinders 3L, 3R based on the outputs of the stroke detectors 5 and 6 (step 100).

And the pitch cylinder 2 corresponding to the above stroke length L
The target stroke length 1ref for L and 2R is read (step 20
0), and a deviation Δ1 = 1ref-1 between the target stroke length 1ref and the actual stroke length 1 of the pitch cylinders 2L, 2R detected in step 100 is calculated (step 30).
0). Then, the CPU 70 creates and outputs a control signal corresponding to the deviation Δ1 (step 400), and this signal is applied to the solenoid 8a or 8b via the D / A converter 72 and the drive circuit 73.

Since the CPU 70 executes such a procedure, the lift cylinders 2L, 2R are operated by operating the lever 10 shown in FIG. 3, for example.
When the stroke length L is changed, the pitch cylinders 3L and 3R are adjusted so that the change in the blade edge angle due to the change in the height of the blade 1 is corrected, that is, the deviation Δ1 shown in step 300 becomes zero. Is activated. Therefore, the blade angle of the blade 1 always maintains the reference blade angle shown in FIG. 3 regardless of the stroke length of the lift cylinders 2L, 2R.

When the lift cylinders 2L and 2R are retracted and the blade 1 is moved upward, a signal corresponding to the deviation Δ1 is applied to the solenoid 8b, whereby the pitch cylinder 3
L and 3R are extended. On the other hand, when the blade is moved downward, a signal corresponding to the deviation Δ1 is applied to the solenoid 8b, which causes the cylinders 3L and 3R to retract.

According to the above-mentioned embodiment, the blade, which was conventionally only able to be raised to the height shown in FIG. 6, can be raised to the height shown in FIG.

In the above-mentioned embodiment, the blade 1 is raised and lowered in a manner parallel to the front surface of the front guard 4, but the cutting edge angle of the blade 1 is changed from the state in which the distance between the upper portion of the blade 1 and the front guard 4 becomes less than a certain value. Even if the correction is performed, it is practically sufficient. In that case, the memory 71 stores the change pattern of the target stroke length 1ref as shown in FIG. It is of course possible to adopt the change pattern shown in FIG. 11 which is obtained by linearly approximating the curved portion of the pattern shown in FIG. Further, the change pattern shown in FIG. 12 may be adopted.

In short, the memory 71 has a lift cylinder at each height position of the blade 1 so that the blade angle of the blade 1 corresponds to each height position of the blade 1 during operation of the lift cylinders 2L and 2R. The target stroke length 1ref of the pitch cylinders 3L and 3R corresponding to the stroke length L can be stored.

In the above embodiment, the lift cylinder stroke length L and the pitch cylinder 3 are set so that the blade angle of the blade 1 is maintained at the reference blade angle θ regardless of the height position of the blade 1.
Memory 71 for the correspondence with the target stroke length 1ref for L and 3R
However, the memory 71 may store therein a correspondence relationship such that different target cutting edge angles are obtained depending on whether the height position of the blade 1 is low or high. .

In the memory 71, when the height position of the blade 1 is low, a cutting edge angle suitable for excavation is obtained, and when the height position of the blade 1 is high, the blade 1 does not interfere with the front guard 4 and soil If the correspondence between the lift cylinder stroke length L and the pitch cylinder target stroke length 1ref is stored in order to obtain a cutting edge angle that does not remain in the blade 1, excavation was performed with the blade 1 lowered. When a series of excavation work is performed later in which the blade 1 is raised to remove soil from the blade 1, work efficiency of the excavation work is improved and interference between the blade 1 and the front guard 4 is prevented.

That is, the pitch cylinder stroke length 1ref corresponding to the lift cylinder stroke length L detected by the lift cylinder stroke length detector 5 is read from the memory 71, and the read pitch cylinder stroke length is read.
1ref and the pitch cylinder stroke length 1 detected by the pitch cylinder stroke length detector 6 match so that
Pitch cylinders 3L and 3R are controlled. Then, when the blade 1 is low, excavation is performed with a cutting edge angle suitable for excavation, and when the blade 1 is high, the sand is left in the blade 1 without causing interference with the front guard 4. Can be dropped without.

In this way, during the series of excavation work, the blade angle of the blade 1 is constantly changed to the optimum angle, so that the sand 1 is completely removed, and the blade 1 having the blade angle suitable for excavation always provides the maximum amount. The earth and sand will be excavated, and excavation work can be performed efficiently. Moreover, since there is no interference with the front guard 4 when the blade 1 moves up, the safety and durability of the bulldozer can be improved.

Next, an example in which the change pattern shown in FIG. 12 is adopted will be described. In this case, the limit cylinders can control the pitch cylinders 3L, 3R.

Table 1 below shows the detection contents of the switches SW1 to SW5 used in this case.

FIG. 3 conceptually shows the arrangement of the switches SW1 to SW5. The switch SW5 is configured to continuously output the ON signal while the stroke lengths of the cylinders 2L and 2R are L2 to L3.

The following Table 2 shows the solenoid 8 of the servo valve 8 shown in FIG.
The conditions for operating a and 8b are shown below.

FIG. 13 (a) shows a state where the stroke lengths of the lift cylinders 2L and 2R are L1 and the stroke lengths of the pitch cylinders 3L and 3R are 11, and in this state, the pitch cylinders 3L and 3R reach the retracted stroke end. Then switch SW3 is on.

When the lever 10 shown in FIG. 3 is operated to the right from this state, the lift cylinders 2L, 2R are retracted and the blade 1
Is raised. At this time, the switch SW2 is on and the switch SW4 is off. Here, when the cylinders 2L, 2R reach the intermediate length L2, the switch SW5 is turned on, so that the condition for operating the solenoid 8b in Table 2 above is satisfied, and this solenoid 8b is energized.

As a result, the valve 8 shown in FIG. 3 is switched to the position B side and the pitch cylinders 3L and 3R are extended, whereby the inclination of the blade 1 is corrected. Then, when the pitch cylinders 3L, 3R are extended to the stroke end on the extension side (the stroke at this time is 13) as shown in FIG. 7C, the switch SW4 is turned on to the neutral position of the valve 8. Will be restored. That is, the extension operation of the cylinders 3L and 3R is stopped.

It should be noted that FIG. 7C shows a state in which the lift cylinders 2L and 2R are retracted until the stroke length becomes L3. In this state, the blade edge angle of the blade 1 matches the blade edge angle shown in FIG.

When the lever 10 shown in FIG. 3 is tilted to the left or right from the state of FIG. 13 (c), the switch SW1 is turned on and the extension operation of the lift cylinders 2L, 2R is started. At this point, the switch SW3 is in the off state and the switch SW5 is in the on state.

When the cylinders 2L and 2R are extended until the stroke length of the cylinders 2L and 2R reaches the intermediate length L2 as shown in FIG. 7D, the switch SW5 is turned off, so that the operating condition of the solenoid 8a in Table 2 above is satisfied. .

As a result, the solenoid 8a is energized and the pitch cylinder 3
L and 3R degenerate operation, and this operation is performed when the switch SW3 is turned on, that is, the stroke length of the cylinders 3L and 3R is 11
It will be stopped when it becomes.

Thus, the stroke lengths of the pitch cylinders 3L and 3R change in the manner shown in FIG. 12 according to the change in stroke length of the lift cylinders 2L and 2R.

In each of the above embodiments, the pitch cylinders 3L and 3R are operated simultaneously, but if they are operated individually, the blade 1 can be tilted as shown in FIG.

The present invention can be applied to the case where the blade 1 is tilted in this way. That is, when performing the above-mentioned tilt, since a separate switching valve is provided for the pitch cylinders 3L, 3R, the stroke length change pattern for the blade edge angle correction of the lift cylinders 3L, 3R with respect to the stroke length changes of the lift cylinders 2L, 2R is set. , The tilt angle is set beforehand for each tilt angle, and if the above-mentioned changeover valves are controlled so that the stroke lengths of the cylinders 3L, 3R are changed according to this pattern, the blade edge angle of the tilted blade can be corrected. You can

[Effect of device]

According to the present invention, since it is possible to correct the blade edge angle change due to the operation of the lift cylinder, it is possible to lift the blade to a sufficient height, and when the blade is lifted, It is possible to avoid the inconvenience that the earth and sand remain.

Furthermore, when the height position of the blade is low, the cutting edge angle is suitable for excavation, and when the height position of the blade is high, the blade does not interfere with the front guard, and the sand and sand do not remain in the blade. Since the cutting edge angle can be set, the work efficiency of excavation work can be dramatically improved, and the safety and durability of the bulldozer can be dramatically improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a blade control device according to the present invention, and FIG. 2 is a controller 7 shown in FIG.
FIG. 3 is a flowchart showing an example of a hydraulic circuit for operating a lift cylinder and a pitch cylinder, FIG. 4 is a side view showing a configuration of a dozer portion of a bulldozer, and FIG. 5 is a dozer. FIG. 6 is a side view showing the configuration of the parts, FIG. 6 is a conceptual diagram showing the manner in which the blade edge angle changes when the lift cylinder is retracted, and FIG. 7 is a blade edge angle when the pitch cylinder is extended. Conceptual diagrams showing changes, FIGS. 8 and 9 are conceptual diagrams showing aspects of blade edge angle correction control, and FIGS. 10, 11, and 12 are lift cylinders for blade edge angle correction, respectively. 13 is a graph showing the relationship between the stroke length and the stroke length of the pitch cylinder, and FIGS. 13 (a) to 13 (d) are conceptual diagrams showing the control mode of the pitch cylinder according to the pattern shown in FIG. 12, and FIG. Is the blade Shows an embodiment of the bets, 15
The figure is a diagram showing the manner in which the blade edge angle changes. 1 …… Blade, 2L, 2R …… Lift cylinder, 3L, 3R ……
Pitch cylinder, 4 front guard, 5 lift cylinder stroke length detector, 6 pitch cylinder stroke length detector, 7 controller, 8 servo valve, 8a, 8b solenoid, 9 Switching valve, 10 …… Lever.

Claims (1)

[Scope of utility model registration request] 1. A blade control device for a bulldozer that changes the blade edge angle by driving a lift cylinder and a pitch cylinder, respectively, and lift cylinder stroke length detection means for detecting the stroke length of the lift cylinder; and the pitch cylinder. Pitch cylinder stroke length detection means for detecting the stroke length, the blade edge angle, so that the blade edge angle corresponding to each height position of the blade during operation of the lift cylinder, at each height position of the blade Storage means for storing a target stroke length of the pitch cylinder corresponding to the lift cylinder stroke length, and a pitch cylinder target corresponding to the lift cylinder stroke length detected by the lift cylinder stroke length detection means during operation of the lift cylinder. stroke A blade control device for a bulldozer, comprising: a control unit for controlling the pitch cylinder so that the target stroke length of the pitch cylinder and the detected pitch cylinder stroke length match with each other by reading the length from the storage unit.