JP2001262630A - Dozer controller of shovel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dozer controller of a shovel causing no shortage of driving force without increasing capacity of a pump when special dozing work is carried out even if the pump having low maximum pressure is used for the dozer since a different pump is used for traveling and the dozer. SOLUTION: When special dozing work is carried out, oil of a main pump 11 for an actuator other than a dozer cylinder 23 is combined with oil from a dozer pump 24 to supply the oil to dozer cylinders 22, and a large quantity of flow can be ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dozer control device for a shovel provided with a dozer for leveling and soil carrying work.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 5, an excavator has an upper revolving structure 2 mounted on a lower traveling structure 1 so as to be rotatable around a vertical axis. Bucket 5, and these driven booms, arms,
A work attachment 9 having the bucket cylinders 6, 7, 8 is attached.

In such an excavator, a dozer 10 is often mounted on the lower traveling body 1 in recent years.

[0004] The dozer 10 is moved up and down by a dozer cylinder (not shown) as shown in the figure, and performs an original work such as a leveling work for leveling the ground while traveling in a ground contact state and a soil carrying work for pushing and carrying the soil. In addition to the work attachment (hereinafter referred to as a normal dozer work), when washing the undercarriage, the body is lifted by touching the ground on the side opposite to the grounded work attachment 9 or is grounded independently to stabilize the body during work. It also performs an operation to perform an outrigger function (hereinafter referred to as a special dozer operation).

[0005] Here, if the hydraulic pump, which is a supply source of hydraulic oil to the dozer cylinder, is shared with a main pump for other actuators including a hydraulic motor for traveling, the traveling pump is normally operated every time the dozer 10 is raised and lowered. It is not preferable since the running operation is adversely affected, for example, the running speed changes due to a change in the amount of oil supplied to the hydraulic motor for use.

For this reason, conventionally, a pump different from the main pump (hereinafter referred to as a dozer pump) is usually used for the dozer cylinder. In this case, an inexpensive gear pump is used unlike the main pump to reduce the cost. Is used.

[0007]

However, according to this method, since the maximum working pressure of the gear pump is lower than that of another pump (for example, a piston pump) used for the main pump, it is higher than that during normal dozer work. Thrust may be insufficient during a special dozer operation requiring thrust.

As a countermeasure against this point, conventionally, a large diameter is used for the dozer pump so that the cylinder diameter of the dozer cylinder is increased and a large flow rate can be secured accordingly.

As a result, the cost is increased, the effect of using an inexpensive gear pump is not only reduced, but also the engine load is increased by the use of the large capacity pump, and the engine speed is increased during simultaneous operation of the traveling pump and the dozer pump. The number decreases and the traveling speed decreases, which usually hinders dozer work.

It is conceivable to perform pump horsepower control to suppress a decrease in the engine speed. However, even if this pump horsepower control is performed, a speed change due to a change in flow rate occurs. No, it is not a fundamental solution.

Therefore, the present invention provides a pump for running a special dozer without increasing the capacity of the pump even if separate pumps are used for the traveling and the dozers, and a pump having a low maximum pressure is used for the dozer. An object of the present invention is to provide a shovel dozer control device that does not cause a shortage of thrust.

[0012]

According to a first aspect of the present invention, there is provided a lower traveling structure, an upper revolving structure mounted on the lower traveling structure, a work attachment mounted on the upper revolving structure, and the lower traveling structure. A plurality of hydraulic actuators including a traveling hydraulic motor for traveling the body, a main pump for supplying pressure oil to the plurality of hydraulic actuators, a dozer provided on the lower traveling body, a dozer cylinder for raising and lowering the dozer, In a shovel provided with a dozer pump for supplying pressurized oil to the dozer cylinder, dozer operation control means for supplying oil from the main pump to the dozer cylinder when the dozer is operated other than during traveling is provided.

According to a second aspect of the present invention, in the configuration of the first aspect, the dozer operation control means merges the oil from the main pump with the oil from the dozer pump when the dozer is operating other than during traveling to the dozer cylinder. It is configured to supply.

According to a third aspect of the present invention, in the configuration of the first aspect, the dozer operation control means switches the pressure oil supply source for the dozer cylinder from the dozer pump to the main pump when the dozer is operated other than during traveling. It was done.

According to a fourth aspect of the present invention, in any one of the first to third aspects, the operation of the dozer cylinder is controlled downstream of the traveling control valve for controlling the operation of the traveling hydraulic motor via the center bypass passage. A dozer control valve is provided.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a detecting means for detecting that the dozer is in operation other than when the vehicle is running is provided. It is configured to supply oil from the main pump to the dozer cylinder based on a detection signal from the means.

According to a sixth aspect of the present invention, in the configuration of the fifth aspect, as the detecting means, a traveling operation detecting means for detecting an operation amount of the traveling control valve, and a dozer operation detecting for detecting an operating amount of the dozer control valve. Means, and the dozer operation control means is configured to determine, based on the detection signals from the two detection means, that the dozer is operating other than during traveling.

According to a seventh aspect of the present invention, in the configuration of any one of the first to sixth aspects, the dozer operation control means includes a flow control valve for controlling an amount of oil supplied to the dozer cylinder and an operation amount of the dozer control valve. The controller is configured to control the opening of the flow control valve accordingly.

According to an eighth aspect of the present invention, in the configuration of the seventh aspect, the cutoff valve for joining oil flowing through the center bypass passage of the traveling control valve to a hydraulic actuator other than the traveling hydraulic motor is provided as the flow control valve. It was used.

According to the above configuration, the oil of the main pump is supplied to the dozer cylinder at the time of the dozer operation other than the traveling, that is, at the time of the special dozer operation.

That is, in the present invention, the oil from the main pump joins the oil from the dozer pump and is supplied to the dozer cylinder. Therefore, a large flow rate can be ensured in the dozer cylinder. Therefore, even when a gear pump having a low maximum pressure is used as the dozer pump and a large-diameter cylinder is used as the dozer cylinder, it is possible to secure a necessary flow rate for the dozer cylinder and obtain a high thrust.

In contrast, in claim 3, the pressure oil supply source for the dozer cylinder is switched from the dozer pump to the main pump. Thus, even when a gear pump is used as the dozer pump and a cylinder having a relatively small diameter is used as the dozer cylinder, the thrust required for the dozer cylinder can be secured.

For this reason, there is no adverse effect (such as an increase in cost and a decrease in engine speed during simultaneous operation of both pumps and a decrease in traveling speed) accompanying an increase in the capacity of the dozer pump.

According to the fourth aspect of the present invention, since the dozer control valve is provided on the downstream side of the traveling control valve via the center bypass passage, the pressure oil may be merged or switched during traveling. In addition, there is no possibility that the running speed will change due to the dozer operation during simultaneous operation of the dozer and running (normal dozer work).

According to the fifth and sixth aspects of the present invention, the detecting means detects that the operation is a special dozer operation, and the merging or switching operation of the oil is automatically performed by the dozer operation control means.

According to the seventh and eighth aspects, the supply flow rate to the dozer cylinder is controlled in accordance with the operation amount of the dozer control valve. Street dozer operation can be obtained.

In this case, according to the configuration of claim 8, the cut valve originally provided in the hydraulic circuit of the shovel can also be used as the flow control valve of the merging control means, so that it is not necessary to add another dedicated valve. This simplifies the circuit configuration,
Cost is low.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment shown in FIGS. 1 and 2 is a construction in which oil from both main and dozer pumps is combined and supplied to a dozer cylinder during a special dozer operation, and a second embodiment shown in FIGS. In this mode, the pressure oil supply source for the dozer cylinder is switched from the dozer pump to the main pump during a special dozer operation. This will be described below.

First Embodiment FIG. 1 shows only a portion related to traveling and dozer operation in a hydraulic circuit of the entire shovel.

Reference numeral 11 denotes a first main pump, and 12 denotes a second main pump. Basically, a first traveling motor (for example, a traveling motor on the right side of the lower traveling body) 13 on the left side of FIG. And both bucket and boom cylinders (not shown) are driven, and the second main pump 1
The second traveling motor (the traveling motor on the left side) 14 on the right side of the figure, and a turning motor and an arm cylinder (not shown) are driven by the oil from 2.

The left and right actuator systems (hereinafter referred to as left actuator system and right actuator system) include:
A control valve for individually controlling the operation of each actuator is provided in tandem with the traveling control valves 15 and 16 as the most upstream, respectively, and a bypass line 1 passes through a bypass passage of each control valve.
7 and 18 and the bypass line 1
Travel control valves 15 and 16 in 7 and 18
Oil supply lines 19 and 20 for supplying oil to the actuators other than the traveling motor are branched and connected to the downstream side of the motor.

A traveling straight valve 21 is provided between the main pumps 11, 12 and the traveling control valves 15, 16, and performs a combined operation such as raising and lowering the boom while traveling. At this time, the straight travel valve 21 switches from the normal position A in the figure to the straight travel position B. Thereby, while the oil from the first main pump 11 flows toward the actuators other than the traveling motors 13 and 14 via the oil supply lines 19 and 20, the second main pump 1
Since the oil from 2 flows in parallel to both traveling motors 13 and 14 via both traveling control valves 15 and 16, traveling straightness is maintained.

Reference numeral 22 denotes a dozer cylinder, reference numeral 23 denotes a dozer control valve for controlling the operation of the dozer cylinder 22, 22, and this dozer control valve 23 is an oil supply line 19 in the left actuator system.
The dozer pump 24 is connected to a point immediately upstream of the dozer control valve 23 in the oil supply line 19.

On the other hand, a hydraulic pilot type cut valve 25 is provided at the most downstream side of the center bypass line 17 in the left actuator system.

The degree of opening of the cut valve 25 changes between a fully open position A and a fully closed position B as shown in the figure, and the oil in the center bypass line 17 is returned to the full tank T at the fully open position A, as is well known. .

On the other hand, when the opening of the cut valve 25 is reduced,
The corresponding amount of the center bypass oil is sent to the actuator (for example, an arm cylinder) of the right actuator system via the junction valve 26 for increasing the speed.

The degree of opening of the cut valve 25 is controlled by the secondary pressure of an electromagnetic proportional pressure reducing valve (hereinafter simply referred to as a proportional valve) 27, and the proportional valve 27 is controlled by a controller 28.

The controller 28 is supplied with a speed increasing signal for performing the above-described inherent speed increasing operation of the cut valve, while operating signals of the traveling control valves 15 and 16 and operating signals of the dozer control valve 23. (For example, obtained by converting a remote control pressure from a remote control valve (not shown) into an electric signal by a pressure sensor).

In FIG. 1, reference numerals 29 and 30 denote check valves for preventing reverse flow of oil between the main pump and the dozer pump 24, and 31 denotes an excess flow from the main pump to the dozer control valve 23. A throttle 32 for reducing the amount of combined oil so as not to flow is a relief valve 32 provided on the discharge side of the dozer pump 24.

In the above configuration, the operation of this device is shown in FIG.
Will be described together.

A. At the time of traveling and during normal dozer work At this time, since a traveling operation signal is input to the controller 28 (YES in step S1 in FIG. 2), no operation signal is sent from the controller 28 to the proportional valve 27, so Remains at the fully open position a in the figure.

In this state, the center bypass line 17
Is returned to the tank T and does not flow to the dozer control valve 23 side, so that only the oil from the dozer pump 24 is supplied to the dozer cylinder 22.

B. At the time of the special dozer work At this time, the traveling operation signal is not input to the controller 28 (NO in step S1 of FIG. 2), and only the dozer operation signal is input (YES in step S2).
A secondary pressure according to the dozer operation amount is sent from the proportional valve 27 to the cut valve 25 (step S3), and the opening of the cut valve 25 is reduced.

Accordingly, the amount of oil corresponding to the operation amount of the dozer from the center bypass line 17 is combined with the oil from the dozer pump 24 and sent to the dozer cylinder 22.

As a result, a large flow rate can be supplied to the dozer cylinder 22. Therefore, even when a gear pump having a low maximum pressure is used as the dozer pump 24 and a large-diameter cylinder is used as the dozer cylinder 22, a required flow rate can be secured for the dozer cylinder 22 and a high thrust can be obtained. There is no need to increase the capacity.

In this case, the dozer control valve 2
3 is provided on the downstream side of the traveling control valve 15 via the center bypass passage 15a, so that an erroneous operation signal is input to the controller 28 or the controller 28
Even if there is an erroneous output to the proportional valve 27, there is no possibility that the above-mentioned merging action will be performed during traveling, and the traveling speed may change due to dozer operation during normal dozer work in which traveling and dozer operation are performed simultaneously. There is no.

Further, the flow rate of the merged flow to the dozer cylinder 22 is controlled by the proportional valve 27 and the cut valve 25 in accordance with the operation amount of the dozer control valve 23, so that a sufficient and sufficient amount of oil is supplied to the dozer cylinder 22. ,
The dozer operation according to the operator's intention can be obtained.

It should be noted that the pressure of the dozer cylinder 22 may exceed the maximum pressure of the dozer pump 24 depending on working conditions during special work. In this case, after the dozer cylinder pressure exceeds the dozer pump maximum pressure, only oil from the main pump side is supplied to the dozer cylinder 22. At this time, the check valve 30 prevents the oil from flowing back to the dozer pump 24 side.

Second Embodiment Only differences from the first embodiment will be described.

Check valve 29 in oil supply line 19
A hydraulic pilot type switching valve 34, which is controlled to be switched between the dozer pump position A and the main pump position B by a switching control valve 33, is provided on the downstream side of the valve. When the switching valve 34 is switched to the main pump position B, The oil from the main pump side (bypass line 17) is supplied to the dozer cylinder 22 instead of the oil from the dozer pump 24 up to that point.

A pressure sensor 35 for detecting the pressure of the dozer cylinder 22 and sending it to the controller 28 is provided.
The dozer cylinder pressure is a predetermined value (for example, dozer pump 24
200 kgf / c at a pressure close to the maximum pressure of
m ² . When the pressure reaches the switching pressure, the controller 28 outputs a switching signal to the switching control valve 33.

As a result, the switching valve 34 is switched to the main pump position B, and the high pressure oil on the main pump side is supplied to the dozer cylinder 22 instead of the oil from the dozer pump 24.

The operation of this point will be further described with reference to FIG. 4. In the normal dozer operation, since the switching valve 33 is at the dozer pump position a, relatively low-pressure oil from the dozer pump 24 is supplied to the dozer cylinder 22. Is done.

On the other hand, during the special dozer operation, the controller 28 determines that the operation is a special dozer operation in steps S1 and S2 of FIG.
When the dozer cylinder pressure Pd reaches the switching pressure Pds by the pressure signal from the controller (when YES in step S3),
That is, when a high pressure is actually required, a pump switching signal is sent from the controller 28 to the switching control valve 33 (step S4), and the switching valve 34 is switched to the main pump position B.

Further, a cut valve fully closed command signal is sent from the controller 28 to the proportional valve 27, the cut valve 25 is switched to the fully closed position B, and high pressure oil from the main pump side is supplied to the dozer cylinder 22.

As described above, in the first embodiment, a large-diameter cylinder is used as the dozer cylinder 22 to secure a required flow rate by the merging action of pump oil to obtain a large thrust. In the embodiment, a configuration is adopted in which high-pressure oil is supplied to the dozer cylinder 22 to secure the required thrust of the dozer cylinder 22. Therefore, a cylinder having a smaller diameter than that of the first embodiment can be used as the dozer cylinder 22.

As the switching control valve 33, a switching valve shown in the figure or an electromagnetic proportional pressure reducing valve may be used.

Other Embodiments (1) As a modified example of the second embodiment, as shown by a two-dot chain line in FIG. 3, a switch which is turned on during a special dozer operation (a switch manually operated by an operator, A switch or the like that is turned on by the dozer cylinder pressure) may be provided, and the controller 28 may output a pump switching command and a cut valve fully closing command signal when the switch 36 is turned on.

(2) As a modification of the first embodiment, a merging operation may be performed by a switch operation.

(3) In the above embodiments, the cut valve originally provided in the hydraulic circuit of the shovel is used as the flow control valve of the merging control means. However, a dedicated flow control valve other than the cut valve is used. May be used.

In this case, the flow control valve is connected to the oil supply line 19
May be provided immediately upstream of the junction of oil from the dozer pump 24.

(4) In the special dozer work, oil is combined in the first embodiment, and the pressure oil supply source is switched from the dozer pump to the main pump in the second embodiment. However, as a compromise between the two embodiments, Alternatively, a configuration may be adopted in which both pump oils are combined until the dozer cylinder pressure reaches a predetermined value, and only the main pump oil is supplied when the dozer cylinder pressure exceeds the predetermined value.

[0063]

As described above, according to the present invention, the oil from the main pump is supplied to the dozer cylinder at the time of the special dozer operation (in the second aspect, the oil from the main pump is combined with the oil from the dozer pump). Since the pressure oil supply source is switched from the dozer pump to the main pump in the third aspect of the invention, a sufficient flow rate or pressure is ensured even when a gear pump having a low maximum pressure is used as the dozer pump. Dozer thrust can be obtained.

As a result, there is no adverse effect associated with the increase in the capacity of the dozer pump (increase in cost, decrease in engine speed during simultaneous operation of both pumps, and decrease in traveling speed).

According to the fourth aspect of the present invention, since the dozer control valve is provided on the downstream side of the traveling control valve through the center bypass passage, there is a possibility that the joining or switching operation of the pressure oil may be performed during traveling. In addition, there is no possibility that the running speed will change due to the dozer operation during simultaneous operation of the dozer and running (normal dozer work).

According to the fifth and sixth aspects of the present invention, it is detected by the detecting means that the operation is a special dozer operation, and the merging or switching operation of the oil is automatically performed by the dozer operation control means.

According to the seventh and eighth aspects of the present invention, the supply flow rate to the dozer cylinder is controlled in accordance with the operation amount of the dozer control valve. Street dozer operation can be obtained.

In this case, according to the invention of claim 8, the cut valve originally provided in the hydraulic circuit of the shovel can also be used as the flow control valve of the merging control means, so that it is not necessary to add another dedicated valve. This simplifies the circuit configuration,
Cost is low.

[Brief description of the drawings]

FIG. 1 is a hydraulic control circuit diagram according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the embodiment.

FIG. 3 is a hydraulic control circuit diagram according to a second embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the embodiment.

FIG. 5 is a schematic side view of a general shovel.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving superstructure 9 Work attachment 3 Boom constituting work attachment 4 Same arm 5 Same bucket 6 Boom cylinder 7 Arm cylinder 8 Bucket cylinder 13, 14 Traveling motor 10 Dozer 11, 12 Main pump 15, 16 For traveling Control valve 22 Dozer cylinder 23 Dozer control valve 24 Dozer pump 25 Cut valve (flow control valve) 27 Electromagnetic proportional pressure reducing valve for cut valve control constituting dozer operation control means 28 Same controller 33 Switching control constituting dozer operation control means Valve 34 Same switching valve 35 Same pressure sensor 36 Same switch

Continued on front page F-term (reference) 2D003 AA01 AB04 AC02 BA01 BA02 BB01 CA04 DA03 DA04 DB02 3H089 AA72 BB15 BB19 BB27 CC01 CC08 CC11 DA02 DB03 DB33 DB44 DB46 DB47 DB48 DB49 EE17 EE22 EE31 FF02 FF12 GG02 JJ02

Claims (8)

[Claims] 1. A plurality of vehicles including a lower traveling structure, an upper revolving structure mounted on the lower traveling structure, a work attachment mounted on the upper revolving structure, and a traveling hydraulic motor for traveling the lower traveling structure. A hydraulic actuator, a main pump for supplying pressure oil to the plurality of hydraulic actuators, a dozer provided on the lower traveling body, a dozer cylinder for raising and lowering the dozer, and a dozer pump for supplying pressure oil to the dozer cylinder. A dozer control device for supplying oil from the main pump to the dozer cylinder when the dozer is operated other than when the vehicle is running. 2. The dozer operation control means is configured to combine the oil from the main pump with the oil from the dozer pump and supply the oil to the dozer cylinder when the dozer is operated other than during traveling. The dozer control device for a shovel according to claim 1. 3. The dozer operation control means according to claim 1, wherein the pressure oil supply source for the dozer cylinder is switched from the dozer pump to the main pump when the dozer is operated other than during traveling. Excavator dozer controller. 4. A dozer control valve for controlling the operation of a dozer cylinder is provided downstream of the traveling control valve for controlling the operation of the traveling hydraulic motor via a center bypass passage. 4. The dozer control device for a shovel according to any one of claims 3 to 3. 5. A dozer operation control means for detecting when the dozer is operating other than during running, wherein the dozer operation control means supplies oil from the main pump to the dozer cylinder based on a detection signal from the detection means. The dozer control device according to claim 1, wherein the dozer control device is configured to supply the dozer control device. 6. The detecting means includes a traveling operation detecting means for detecting an operation amount of the traveling control valve, and a dozer operation detecting means for detecting an operating amount of the dozer control valve. 6. The dozer control apparatus for an excavator according to claim 5, wherein it is configured to judge that the dozer is operating other than during traveling based on detection signals from both of the detecting means. 7. The dozer operation control means includes a flow control valve for controlling an amount of oil supplied to a dozer cylinder, and a controller for controlling an opening of the flow control valve in accordance with an operation amount of a dozer control valve. The excavator dozer control device according to any one of claims 1 to 6, wherein: 8. A cut-off valve for joining oil flowing through a center bypass passage of a travel control valve to a hydraulic actuator other than a travel hydraulic motor as the flow control valve. Excavator dozer control device.