JPH086345B2 - Bulldozer blade controller - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a blade control device for a bulldozer for the purpose of improving excavation performance, soil transportation performance, ground leveling performance, and the like.

(Prior Art) Conventionally, in the blade control of a bulldozer, as shown in FIG.
The work is performed by a pitching operation in which L and 32R are simultaneously extended or contracted to incline the blade 35 back and forth, and a tilt operation in which one cylinder is extended and the other cylinder is contracted to incline the blade. This kind of technique is provided with two cylinders 32 behind the blade 31 as shown in FIG. 6 (A).
L and 32R are arranged on the left and right, and operating valves 34L and 34R are separately provided between the two cylinders 32L and 32R and the hydraulic pump 33, and in the method of operating independently, the left and right with respect to the hydraulic pump 33. Cylinders 32L and 32R are parallel circuits. Moreover, FIG. 6 (B)
As shown in Figure 2, the two cylinders 32L and 32R and the hydraulic pump 33
Between them, an operation valve for controlling the amount and direction of hydraulic oil to be supplied from the hydraulic pump 33 to the left and right cylinders 32L, 32R.
In the system in which the switching valve 35 that switches between 34 and blade pitching or tilting is provided, the left and right cylinders 32L and 32R with respect to the hydraulic pump 33 are series circuits both during pitching and during tilting. Further, the left and right cylinders 32R and 32L have the same effective area.

(Problems to be Solved by the Invention) In the above-described conventional technique, the left and right cylinders 32L and 32R are operated in parallel in the hydraulic pump 33 shown in FIG. It is necessary to complicate the operation of the operator, and because of the parallel circuit, the pitch speed of the blade becomes slow and there is a problem in workability. The hydraulic pump 33 shown in FIG.
On the other hand, in the system in which the left and right cylinders 32L and 32R are a series circuit, the switching valve 35 has a pitch position a, a single tilt position b, and a double tilt position c, and the a and c positions for operating the left and right cylinders 32L and 32R are Since both are series circuits, there is a drawback that the tilt speed is too fast. Furthermore, of the left and right cylinders 32R and 32L, the effective cross-sectional area on the head side of one cylinder and the effective cross-sectional area on the bottom side of the other cylinder are different, so there is a difference in the stroke between the left and right cylinders 2L and 2R, and the blades are There was a problem of tilting naturally.

(Means for Solving the Problems) The present invention has been made to solve the problems in the above-mentioned conventional technique, and the first aspect of the present invention controls a blade pivotably attached to a bulldozer. In a blade control device for a bulldozer, in which one cylinder is provided on each of the left and right sides between the blade and the bulldozer, the head side effective sectional area of one cylinder is made equal to the bottom side effective sectional area of the other cylinder, and the left and right cylinders are arranged. When operating simultaneously, the hydraulic sources of the left and right cylinders, the operating valve, the switching valve, and the left and right cylinders are connected so as to form a series circuit, and the natural tilt at the pitch, which is a drawback of the series circuit, is prevented. According to the blade control device of the bulldozer, the second (2) claim is the same as the first (1) claim. A blade control device for a bulldozer, characterized in that the fly valve and the pitch switching valve are separately provided.
According to the blade control device of the bulldozer, the tilt switching valve and the pit switching portion are provided separately, the third aspect of the present invention is that the operation valve and the switching valve are the same as those in the first aspect. A blade control device for a bulldozer characterized by interposing at least one flow divider between the hydraulic pump and supplying hydraulic oil in parallel to a cylinder for controlling a blade to enable a power tilt or power pitch operation. To achieve.

(Operation) Even when the left and right cylinders 2L and 2R are series circuits with respect to the hydraulic pump 3 in the above configuration, the head-side effective sectional area of one cylinder is made equal to the bottom-side effective sectional area of the other cylinder. Since the strokes of the left and right cylinders 2L and 2R are the same, it is possible to prevent the blade from being naturally tilted during pitching.

Further, since the hydraulic circuit between the left and right cylinders 2L and 2R for controlling the hydraulic pump and the blades can be arbitrarily switched between a series circuit and a parallel circuit, it is possible to perform work using speed and force properly according to the purpose.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a view showing a first embodiment of the present invention. Reference numeral 1 is a blade whose lower portion is directly pivotally attached to a bulldozer and whose upper portion is 1L and 1R portions which are pivotally attached to the bulldozer via left and right cylinders 2L and 2R, respectively. 3 is a hydraulic pump for supplying hydraulic oil to the left and right cylinders 2L, 2R, and 4 is a hydraulic pump for controlling the amount and direction of hydraulic oil supplied from the hydraulic pump 3 to the left and right cylinders 2L, 2R. The operation valve 5 is a switching valve for switching between pitching and tilting the blade.
Next, the operation will be described. When both the operation valve 4 and the switching valve 5 are operated to the a position, the hydraulic oil discharged from the hydraulic pump 3 is supplied to the bottom chamber of the cylinder 2L. The hydraulic oil discharged from the bottom chamber of the cylinder 2L is drained from the operation valve 4 to the tank via the switching valve 5. At this time, the cylinder 2L extends and the cylinder 2R contracts, so that the blade double tilts to the right. When the switching valve 5 is operated to the b position while the operation valve 4 is still in the a position, the hydraulic oil discharged from the hydraulic pump 3 is supplied from the operation valve 4 to the bottom chamber of the cylinder 2L. The hydraulic oil discharged from the head chamber of the cylinder 2L is transferred from the switching valve 5 to the operation valve 4
After that, it is drained to the tank. At this time, the cylinder 2R remains blocked and the cylinder 2L extends, so the blade single tilts to the right. When the switching valve 5 is operated to the c position while the operation valve 4 is still in the a position, the working oil discharged from the hydraulic pump 3 is supplied to the bottom chamber of the cylinder 2L. The hydraulic oil discharged from the cylinder 2L head chamber is supplied to the bottom chamber of the cylinder 2R. The hydraulic oil discharged from the head chamber of the cylinder 2R is the switching valve 5
Through the operation valve 4 and then drained to the tank. Therefore, at this time, both the left and right cylinders 2L and 2R extend, but since the effective cross-sectional areas of the head chamber of the cylinder 2L and the bottom chamber of the cylinder 2R are made equal, the left and right cylinders 2L and 2R have the same extension amount, and the blades Pitching works without tilting naturally. Both the operating valve 4 and the switching valve 5 are b
When in the position, both left and right cylinders 2L and 2R are blocked. When the operation valve 4 is operated to the c position, the operation opposite to that when the operation valve 4 is operated to the a position is performed, and the description thereof is omitted. FIG. 2 is a view showing a second embodiment of the present invention, in which the switching valve 5 in FIG. 1 is replaced by a tilt switching valve 6
And the switching valve 7 for pitch, which is provided separately, is the first
It is the same as the figure. Next, the operation will be described. When all the operation valves 4 and the switching valves 6 and 7 are operated to the a position, the hydraulic oil discharged from the hydraulic pump 3 is supplied from the operation valve 4 to the cylinder 2L bottom chamber via the switching valve 7.
The hydraulic fluid discharged from the cylinder 2L head chamber is drained from the operation valve 4 to the tank through the switching valve 6. At this time, the right cylinder 2R does not move, the left cylinder 2L extends, and the blade single tilts to the right. The operation valve 4 remains in the a position, and the switching valves 6 and 7 are respectively in the a position and the b position.
When operated to the position, the hydraulic oil discharged from the hydraulic pump 3 is supplied from the operation valve 4 through the switching valve 7 to the bottom chamber of the cylinder 2R. The hydraulic oil discharged from the head chamber of the cylinder 2R is supplied to the bottom chamber of the cylinder 2L via the switching valve 7. The hydraulic oil discharged from the head chamber of the cylinder 2L is drained from the switching valve 6 through the operation valve 4 to the tank. At this time, the left and right cylinders 2L and 2R both extend and the blades perform a pitching operation, but since the effective cross-sectional areas of the head chamber of the cylinder 2R and the bottom chamber of the cylinder 2L are the same, the extension amounts of the left and right cylinders 2L and 2R are the same. Next to
The blade operates pitching without tilting naturally. Next, the operation valve 4 remains in the a position and the switching valve 6
When 7 and 7 are operated to the b position and the a position, respectively, the hydraulic oil discharged from the hydraulic pump 3 is supplied from the operation valve 4 through the switching valve 7 to the bottom chamber of the cylinder 2L. The hydraulic oil discharged from the cylinder 2L head chamber is supplied to the cylinder 2R head chamber. The hydraulic fluid discharged from the bottom chamber of the cylinder 2R is drained from the tank through the switching valve 7 and the operation valve 4. Therefore, at this time, cylinder 2L
Expands and cylinder 2R contracts, so the blade double tilts to the right. When the operation valve 4 is operated to the b position and both the switching valves 6 and 7 are operated to the a position, the left and right cylinders 2L and 2R are blocked and the blades are fixed. Further, when the operation valve 4 is operated to the c position, the left and right cylinders 2L and 2R operate in the opposite manner to the case of the a position, but description thereof will be omitted. FIG. 3 is a diagram showing a third embodiment of the present invention, which is the same as FIG. 1 except that another switching valve 8 is provided instead of the switching valve 5 in FIG. Next, the operation will be described. When both the operation valve 4 and the switching valve 5 are operated to the a position, the hydraulic oil discharged from the hydraulic pump 3 is supplied to the head chamber of the cylinder 2L. The hydraulic oil discharged from the bottom chamber of the cylinder 2L is drained from the operation valve 4 to the tank via the switching valve 8. At this time, the cylinder 2L contracts and the cylinder 2R is fixed, so the blade single tilts to the left by the cylinder 2L. When the switching valve 8 is operated to the b position while the operation valve 4 remains in the a position, the hydraulic oil discharged from the hydraulic pump 3 is supplied from the operation valve 4 to the bottom chamber of the cylinder 2R. The hydraulic oil discharged from the head chamber of the cylinder 2R is drained from the switching valve 8 through the operation valve 4 to the tank. At this time, the cylinder 2L remains blocked and the cylinder 2R extends, so that the blade single tilts to the left by the cylinder 2R. When the switching valve 8 is operated to the c position while the operation valve 4 is still in the a position, the working oil discharged from the hydraulic pump 3 is supplied to the head chamber of the cylinder 2R. The hydraulic oil discharged from the bottom chamber of the cylinder 2R is supplied to the head chamber of the cylinder 2L. The hydraulic oil discharged from the bottom chamber of the cylinder 2L is drained to the tank through the switching valve 8 and the operation valve 4. Therefore, at this time, both the left and right cylinders 2L and 2R contract, but since the effective cross-sectional areas of the head chamber of the cylinder 2L and the bottom chamber of the cylinder 2R are the same, the contraction amounts of the left and right cylinders 2L and 2R are the same, and the blade is Speed pitching works without tilting naturally. If both the operation valve 4 and the switching valve 8 are set to the b position, the left and right cylinders 2L and 2R are both blocked and the blades are fixed. When the operation valve 4 is operated to the c position, the operation opposite to that when the a position is operated is performed, but the description thereof will be omitted. FIG. 4 is a diagram showing a fourth embodiment of the present invention. In addition to the switching valve 5 in FIG. 1, another switching valve 11, 12 and two flow dividers 10L, 1 are provided.
It is the same as FIG. 1 except that 0R is provided. The flow dividing ratio of the flow dividers 10L and 10R is the ratio of the effective sectional areas of the head chambers and rod chambers of the left and right cylinders 2L and 2R. Next, the operation will be described. Table 1 shows the relationship between the positions of the operation valve 4, the switching valves 9, 11, and 12 and the operation of the blades. Since the flow of hydraulic oil is the same as in the first to third embodiments, the description thereof will be omitted. FIG. 5 is a diagram showing a fifth embodiment of the present invention. In addition to the switching valve 5 in FIG. 1, another switching valve 1
4, except that the flow divider 15 is provided. Table 2 shows the relationship between the positions of the operation valve 4, the switching valves 13, 14, and 16 and the operation of the blades.

Since the flow of hydraulic oil is the same as in the first to third embodiments, the description thereof will be omitted. The flow dividing ratio of the flow divider 15 is the ratio of the effective sectional areas of the head chambers and the bottom chambers of the left and right cylinders 2L and 2R.

(Effects of the Invention) As described in detail above, according to the present invention, the following effects are achieved.

(1) Even if the left and right cylinders 2L and 2R are series circuits with respect to the hydraulic pump 3, since the head side effective sectional area of one cylinder and the bottom side effective sectional area of the other cylinder are made equal, Since the cylinders 2L and 2R have the same stroke, it is possible to prevent the blade from tilting naturally during pitching, which prevents the blade body from fluctuating due to load fluctuations on the cutting edge, excavating performance, and soil transportation. It is possible to improve performance and leveling property.

(2) For work on weak soft soil where speed is required, operability can be improved by speed tilt and speed pitch, and the work amount can be greatly increased.

(3) When working on rock where excavation power is required, the work amount can be significantly increased by the power pitch and power tilt.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, FIG. 2 is a diagram showing a second embodiment of the present invention, FIG. 3 is a diagram showing a third embodiment of the present invention, and FIG. FIG. 5 is a diagram showing a fourth embodiment of the invention, FIG. 5 is a diagram showing a fifth embodiment of the invention, and FIGS. 6 and 7 are diagrams showing a conventional technique. 1 …… Blade, 2L …… Left cylinder, 2R …… Right cylinder, 3 …… Hydraulic pump, 4 …… Operating valve, 5-9,11,12,1
3,14,16 …… Switching valve, 10L, 10R, 15 …… Flow divider

Claims (3)

[Claims] 1. A bulldozer blade control device in which a cylinder for controlling a blade pivotably mounted on a bulldozer is provided between the blade and the bulldozer, one on the left side and one on the right side of the bulldozer. Make the area equal to the effective area on the bottom side of the other cylinder, and connect the hydraulic sources of the left and right cylinders, the operating valve, the switching valve and the left and right cylinders to form a series circuit when operating the left and right cylinders at the same time. A blade control device for a bulldozer, which is characterized by preventing a natural tilt at a pitch, which is a drawback of the series circuit. 2. The blade control device for a bulldozer according to claim 1, wherein the switching valve is provided separately for the tilt switching valve and the pitch switching valve. 3. In the first aspect, at least one flow divider is interposed between the operation valve and the switching valve to supply hydraulic oil in parallel from a hydraulic pump to a cylinder for controlling a blade. A blade control device for a bulldozer, which enables power tilt or power pitch operation.