JPH0363613B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic circuit for a hydraulic wheel shovel equipped with a plurality of actuators, and more particularly to a hydraulic circuit for a hydraulic wheel shovel that can improve operability when a plurality of actuators are operated simultaneously. .

1 and 2 are explanatory diagrams showing the overall structure of a hydraulic wheel shovel to which the present invention is applied, with FIG. 1 being a side view and FIG. 2 being a plan view. In these figures, 1 is a rotating body, 2 is a running body, 3 is a turning motor that turns the rotating body 1, 4 and 5 are front wheels and rear wheels that constitute the running body 2, respectively, and 6 is a vehicle that makes the running body 2 run. A running motor, 7 an outrigger, and 14 a blade rotatably provided on the running body 2.

Further, 8 is a boom rotatably provided on the revolving structure 1, 9 is an arm rotatably provided on the boom 8, and 10 is a bucket rotatably provided on the arm 9. , and a bucket 10 constitute the front.

Further, 11 is a boom cylinder that rotates the boom 8, 12 is an arm cylinder that rotates the arm 9, and 13 is a bucket cylinder that rotates the bucket 10, which together with the aforementioned swing motor 3, travel motor 6, etc. It forms an actuator included in a hydraulic wheel shovel.

In the hydraulic wheel shovel configured in this way, the traveling body 2 travels by driving the traveling motor 6, the rotating body 1 and the front rotate by driving the swing motor 3, and the boom cylinder 11 , arm cylinder 12,
By appropriately operating the bucket cylinder 13, the boom 8, the arm 9, and the bucket 10 are rotated, and desired work such as excavation can be performed.

FIG. 3 is a circuit diagram showing an example of a conventional hydraulic circuit provided in such a hydraulic wheel shovel. In these figures, 20 is a first hydraulic pump, 21 is an outrigger directional control valve that is interposed between the first hydraulic pump 20 and the outrigger 7 and controls the drive of the outrigger 7, and 22 is an outrigger directional control valve. A first boom directional switching valve 23 is interposed between the directional switching valve 21 and the boom cylinder 11 and controls the drive of the boom cylinder 11; A bucket belt directional control valve 24 is interposed between the bucket belt directional control valve 3 and the travel motor 6, and controls the drive of the bucket cylinder 13.
This is a first travel direction switching valve that controls the drive of the travel motor 6. In addition, the outrigger directional control valve 2
1. The first boom directional switching valve 22, the bucket directional switching valve 23, and the first running directional switching valve 24 are connected in parallel to the first hydraulic pump 20. The first hydraulic pump 20, the directional control valves 21, 22, 23, 24, the outrigger 7, the boom cylinder 11, the bucket cylinder 33, and the travel motor 6 constitute one independent hydraulic circuit. There is.

Further, 30 is a second hydraulic pump, 31 is a second boom directional control valve that is interposed between the second hydraulic pump 30 and the boom cylinder 11 and controls the drive of the boom cylinder 11, and 32 is a second boom directional switching valve. A second traveling directional switching valve 33 is interposed between the second boom directional switching valve 31 and the traveling motor 6 and controls the driving of the traveling motor 6. 32 is an arm directional switching valve that is interposed between the arm cylinder 12 and controls the drive of the arm cylinder 12; 34 is the arm directional switching valve 3;
This is a swing direction switching valve that is interposed between the swing motor 3 and the swing motor 3 and controls the drive of the swing motor 3. Note that the second boom directional switching valve 31, the second running directional switching valve 32, the arm directional switching valve 33, and the swing directional switching valve 34 are connected in parallel to the second hydraulic pump 30. It has been done. and,
The above-mentioned second hydraulic pump 30 and directional switching valve 3
1, 32, 33, 34, boom cylinder 11, travel motor 6, arm cylinder 12, swing motor 3
A separate independent hydraulic circuit is constructed.

In addition, in the case of the above-mentioned hydraulic wheel shovel, as is well known, only one drive source for driving the front wheels 4 and rear wheels 5 is provided, such as the travel motor 6 shown in FIG. If there is a single drive source, and this single drive source is a travel motor 6 as in the prior art shown in FIG. Directional switching valve 2
4. Both of the second running direction switching valves 32 are connected, and these first running direction switching valves 24 and the second running direction switching valve 32 are connected.
The travel direction switching valve 32 is switched in conjunction with one operation lever to transfer pressure oil to the travel motor 6.
is supplied to make the traveling body 2 travel.

By the way, the conventional hydraulic circuit configured as described above has problems associated with simultaneous arm/travel and swing/travel operations, as described below.

(1) Generally, when escaping from rough terrain, etc., in a hydraulic wheel shovel, the traveling motor 6 and arm cylinder 12 are operated simultaneously to combine the force from the arm 9 and the traveling force from the traveling body 2. However, even if the intention is to use the arm to generate a large force, in the conventional hydraulic circuit described above, the arm directional control valve 33 and the second traveling direction Since the switching valve 32 is connected in parallel to the second hydraulic pump 30, the oil discharged from the second hydraulic pump 30 is supplied to the travel motor 6, which has a lower operating pressure. There were times when the arm was not strong enough to provide sufficient escape force.

(2) In the case of a hydraulic wheel excavator, simultaneous running and turning operations may be performed while lifting a heavy object, but in the case of the conventional hydraulic circuit described above, the second running direction Since the switching valve 32 and the turning direction switching valve 34 are connected in parallel to the second hydraulic pump 30, the oil discharged from the second hydraulic pump 30 is directed toward the travel motor 6, which has a lower operating pressure. Therefore, the travel speed control and turning speed control intended by the operator could not be realized.

Although not shown in FIG. 3, the blade directional control valve that controls the operation of the blade 14 is also connected in parallel to, for example, the second hydraulic pump 30, so that when simultaneous blade and travel operations are performed, However, it was not possible to realize the blade speed control and travel speed control intended by the operator.

The present invention has been made in view of the actual situation in the prior art, and its purpose is to realize independent operation of the arm and travel during simultaneous operation of the arm and travel, and to realize independent operation of the arm and travel during simultaneous operation of the arm and travel. An object of the present invention is to provide a hydraulic circuit for a hydraulic wheel shovel that can realize independent operations for turning and traveling.

To achieve this objective, the present invention includes a plurality of hydraulic pumps, a plurality of actuators including a single travel motor driven by pressure oil discharged from these hydraulic pumps, and a drive system for these actuators. In the device equipped with a plurality of directional switching valves to be controlled, the directional switching valve connected to the first hydraulic pump of the plurality of hydraulic pumps described above is the first directional switching valve.
It includes a directional switching valve for running and a directional switching valve for an arm connected in tandem at the most downstream side, and the directional switching valve connected to the second hydraulic pump of the plurality of hydraulic pumps mentioned above is a directional switching valve for swinging. It includes a valve and an arm directional switching valve, and also includes a second running directional switching valve connected in tandem at the most downstream side, and the first running directional switching valve and the second running directional switching valve are interlocked. The configuration is such that pressure oil is supplied to the travel motor by switching the drive motor.

Hereinafter, the hydraulic circuit of the hydraulic wheel shovel of the present invention will be explained based on the drawings. FIG. 4 is a circuit diagram showing one embodiment of the present invention.

In this figure, 40 is a first hydraulic pump;
Reference numeral 1 denotes an outrigger directional switching valve that is interposed between the first hydraulic pump 40 and the outrigger 7 shown in FIG. a first travel directional control valve, which is interposed between a single travel motor 6 and controls the drive of the travel motor 6;
3 is interposed between this first travel direction switching valve 42 and the boom cylinder 11, and the boom cylinder 1
a first boom directional control valve that controls the drive of the first boom;
Reference numeral 44 denotes a bucket directional switching valve that is interposed between the first boom directional switching valve 43 and the bucket cylinder 13 and controls the drive of the bucket cylinder 13; 45 indicates a bucket directional switching valve 44; This is a first arm directional switching valve that is interposed between the arm cylinder 12 and the arm cylinder 12 and controls the drive of the arm cylinder 12. In addition, the outrigger directional control valve 41,
First travel directional valve 42, first boom directional valve 43, and bucket directional valve 44
are connected in parallel to the first hydraulic pump 40, and the first arm directional switching valve 45 is connected in tandem to the first hydraulic pump 440 at the most downstream position.

Further, 50 is a second hydraulic pump, 51 is a swing direction switching valve that is interposed between the second hydraulic pump 50 and the swing motor 3, and controls the drive of the swing motor 3, and 52 is a swing direction switching valve. A second boom directional switching valve 53 is interposed between the directional switching valve 51 and the boom cylinder 11 and controls the drive of the boom cylinder 11. A second arm directional switching valve 54 is interposed between the arms and controls the drive of the arm cylinder 12.
3 and the blade 14, the blade 1
55 blade directional control valve for controlling the drive of 4;
This blade directional control valve 54 and travel motor 6
This is a second travel direction switching valve that is interposed between the drive motor 6 and the drive motor 6 and controls the drive of the travel motor 6. In addition, the turning direction switching valve 51 and the second boom direction switching valve 5
2. The second arm directional switching valve 53 and the blade directional switching valve 54 are connected in parallel to the second hydraulic pump 50, and the second traveling directional switching valve 55 is connected to the second hydraulic pump 50. 50 and are connected in tandem at the most downstream position. In addition, the first
The traveling direction switching valve 42 and the second traveling direction switching valve 55 are both connected to a single traveling motor 6, as in the well-known technology, and are switched in conjunction with each other by an operation lever (not shown). It is configured to supply pressurized oil to the traveling motor 6 by using the hydraulic fluid.

In one embodiment configured in this way,
A first travel direction switching valve 42 is connected to the upstream side of the first hydraulic pump 40, and a second arm directional switching valve 53 is connected to the upstream side of the second hydraulic pump 50. Therefore, by switching the first traveling direction switching valve 42, the discharge oil of the first hydraulic pump 40 can be supplied to the traveling motor 6, and by switching the second arm directional switching valve 53. Discharge oil from the second hydraulic pump 50 can be supplied to the arm cylinder 12.
In other words, when operating the arm and travel simultaneously, the first
The second hydraulic pump 40 can be used exclusively for traveling, and the second hydraulic pump 50 can be used exclusively for the arm, and arm-only operation and traveling-only operation can be realized.

Further, a first driving direction switching valve 42 is connected to the upstream side of the first hydraulic pump 40, and a turning direction switching valve 51 is connected to the most upstream side of the second hydraulic pump 50.
is connected, the discharge oil of the first hydraulic pump 40 can be supplied to the traveling motor 6 by switching the first traveling direction switching valve 42, and the turning direction switching valve 51 can also be switched. As a result, the oil discharged from the second hydraulic pump 50 can be supplied to the swing motor 3. That is, during simultaneous operations for turning and traveling, the first hydraulic pump 40 can be used exclusively for traveling, and the second hydraulic pump 50 can be used exclusively for turning, making it possible to realize single-turn operation and single-travel operation. can.

Note that a first running direction switching valve 42 is connected to the upstream side of the first hydraulic pump 40, and a second running direction switching valve 55 is connected in tandem to the most downstream side of the second hydraulic pump 50. Since the blade directional switching valve 54 is connected upstream of the blade, the oil discharged from the first hydraulic pump 40 can be supplied to the running motor 6 by switching the first running directional switching valve 42. , and a directional control valve 5 for the blade.
4, the second hydraulic pump 50
The discharged oil can be utilized for driving the blade 14. That is, when operating the blade and traveling at the same time, the first hydraulic pump 40 is used exclusively for traveling, and the second
The hydraulic pump 50 can be used exclusively for driving the blade, and blade-only operation and traveling-only operation can be realized.

In addition, when operating only for traveling, the first hydraulic pump 4 is switched by switching the first traveling direction switching valve 42 and the second traveling direction switching valve 55.
The oil discharged from the second hydraulic pump 50 and the oil discharged from the second hydraulic pump 50 can be combined and supplied to the traveling motor 6 to cause the traveling body 2 to travel.

Similarly, when operating only the arm alone, by switching the first arm directional switching valve 45 and the second arm directional switching valve 53, the discharge oil of the first hydraulic pump 40 and the second hydraulic pump 50 are controlled. The discharged oil can be combined and supplied to the arm cylinder 12 to rotate the arm 9.

In addition, when operating only for swinging or operating only for blade drive, the directional control valve 5 for swinging
1. By switching the blade directional control valves 54, the discharge oil of the second hydraulic pump 50 can be supplied to the swing motor 3 and the swing body 1 can be turned, or the discharge oil of the second hydraulic pump 50 can be supplied to the swing motor 3. The blade 14 can be driven by oil.

The hydraulic circuit of the hydraulic wheel shovel of the present invention includes:
With the configuration described above, it is possible to realize independent operation of the arm and travel when simultaneously operating the arm and travel, and therefore, it is possible to obtain sufficient escape force on rough ground, and also when turning. - It is possible to realize independent operations for turning and traveling during simultaneous operation of traveling, and therefore, there is an effect that the turning speed control and traveling speed control intended by the operator can be realized. Further, it is possible to realize independent operation of the blade and the travel when operating the blade and the travel simultaneously, and therefore, there is an effect that the blade speed control and the travel speed control intended by the operator can be realized.

[Brief explanation of drawings]

1 and 2 are explanatory diagrams showing the overall configuration of a hydraulic wheel shovel to which the present invention is applied, in which FIG. 1 is a side view, FIG. 2 is a plan view, and FIG. 3 is a conventional hydraulic wheel shovel. FIG. 4 is a circuit diagram showing an example of the hydraulic circuit of the bell. FIG. 4 is a circuit diagram showing an example of the hydraulic wheel shovel of the present invention. 40...First hydraulic pump, 42...First travel direction switching valve, 45...First arm direction switching valve, 50...Second hydraulic pump, 51...Swivel direction switching valve , 53... Second arm directional switching valve, 54... Blade directional switching valve, 55... Second running directional switching valve.

Claims (1)

[Claims] 1. A plurality of hydraulic pumps, a plurality of actuators including a single travel motor driven by pressure oil discharged from these hydraulic pumps, and a plurality of actuators that control the driving of these actuators. In the hydraulic circuit of a hydraulic wheel excavator equipped with a directional switching valve, the directional switching valve connected to the first hydraulic pump of the plurality of hydraulic pumps includes the first traveling directional switching valve, and The directional control valve includes an arm directional control valve connected in tandem downstream, and the directional control valve connected to a second hydraulic pump of the plurality of hydraulic pumps includes a swing direction control valve and an arm directional control valve. , a second traveling direction switching valve connected in tandem at the most downstream side, the first traveling direction switching valve and the second traveling direction switching valve are switched in conjunction to apply pressure to the traveling motor. A hydraulic circuit for a hydraulic wheel shovel characterized by supplying oil. 2. Claim 1, characterized in that the directional switching valve connected to the second hydraulic pump includes a blade directional switching valve disposed upstream of the second running directional switching valve. Hydraulic wheel excavator hydraulic circuit.