JP2011075025A - Traveling linear advancement control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To alleviate a shock when switching straight running.
When traveling straight, the discharge amount of a pump P2 is divided into a right travel switching valve 10 and a left travel switching valve 15, but the discharge amounts of a pump P1 and a pump P4 are maintained as they are. Therefore, the rate at which the flow rate supplied to both travel motors M1, M2 decreases is smaller than in the conventional case. Therefore, it is possible to reduce the shock at the time of the straight travel switching. However, during normal travel, the oil discharged from the pumps P1, P2 and P3, P4 is supplied via the right travel switching valves 1, 10 and the left travel switching valves 15, 29.
[Selection] Figure 1

Description

  The present invention relates to a straight traveling control device that controls the traveling of a construction machine.

  Conventionally, this type of straight traveling control device known in the art uses two pumps and, when traveling straight, distributes the discharge amount of one pump and supplies it to a pair of traveling motors.

JP 2005-297815 A

In the conventional straight travel control device as described above, when the normal travel is performed, the discharge amounts of the two pumps are individually supplied to each travel motor, and when the straight travel is performed, the discharge amount of one pump is divided and supplied. There is a problem in that the traveling speed when traveling straight travels down extremely and a shock occurs when switching.
An object of the present invention is to provide a travel straight-ahead control device that reduces the shock at the time of switching.

  The first invention is provided with two pump systems each having a pair of pumps as one set, one pump system being a left or right traveling pump system, and the other pump system being a left or right traveling pump system. The pump system is used. Each of the travel pump systems has a travel switching valve individually connected thereto, and these travel switching valves are connected in parallel to either the left or right travel motor. A travel switching valve is individually connected to each pump of the other travel pump system, and these travel switching valves are connected in parallel to either the left or right travel motor.

Further, a travel straight valve is connected to a connection process between one pump in the other travel pump system and the travel switching valve connected thereto. The traveling straight valve is connected to one pump in the one traveling pump system and one pump in the other traveling pump system.
When the travel straight valve thus configured is in the normal position, the one pump in the other travel pump system directly communicates with one travel switching valve that controls the other travel motor.

  Further, when the travel straight valve is in the switching position, one travel control valve for controlling one travel motor and one travel control valve for controlling the other travel motor are controlled. The travel switching valve communicates with the travel switching valve in parallel, and the communication between one pump in the other travel pump system and the travel switching valve that controls the other travel motor is blocked.

  According to a second aspect of the present invention, a switching valve for controlling another actuator is connected to the downstream side of the switching valve connected to each pump in both the pump systems, and the switching connected to each pump in one traveling pump system. The valve is connected in parallel to a specific actuator, and the switching valve connected to each pump in the other traveling pump system is connected in parallel to the specific actuator.

When the travel straight valve is in the normal position, one of the pumps in one travel pump system is connected to the travel switching valve connected to the pump and the switching connected to the downstream side of the travel switching valve. The valve is communicated in a parallel connection state, and the one pump in the other traveling pump system is directly communicated with the traveling switching valve that controls the other traveling motor.
Further, when the travel straight valve is in the switching position, one travel switching valve for controlling one travel motor and one travel control for controlling the other travel motor are performed in one pump in the one travel pump system. The one traveling pump is connected to the switching valve for parallel use in a state of being connected in parallel, and the communication between one pump in the other traveling pump system and the traveling switching valve for controlling the other traveling motor is blocked. It communicates with a switching valve on the downstream side of the traveling switching valve connected to one of the pumps in the system.

  According to a third aspect of the present invention, a switching valve for controlling another actuator is connected downstream of the traveling switching valve for controlling the other traveling motor, and the one pump in the other traveling pump system is connected to a parallel passage. It connects to the change-over valve which controls other actuators via. The parallel passage and the travel switching valve that controls the other travel motor are communicated with each other via a throttle and a check valve that allows only the flow from the parallel passage to the travel switching valve.

According to the straight travel control devices of the first and second inventions, it is possible to alleviate a shock when switching during straight travel.
According to the straight travel control device of the third invention, when the load pressure of the actuator connected to the switching valve other than the traveling switching valve is high, the pressure oil supplied to the actuator can be sent to the traveling system.

1 is a circuit diagram showing an embodiment of the present invention.

The illustrated embodiment relates to a power shovel, and includes four pumps P1 to P4. Among these pumps, pumps P1 and P2 constitute one traveling pump system of the present invention, and pumps P3 and P4. Constitutes the other traveling pump system of the present invention.
The pump P1 is connected with the switching valves 1 to 4, and the right traveling switching valve 1 for controlling the right traveling motor M1 in order from the upstream side, the boom switching valve 2 for controlling the boom cylinder 5, An arm second speed switching valve 3 for controlling the second speed of the arm cylinder 6 and a bucket switching valve 4 for controlling the bucket cylinder 7 are provided.

  The switching valves 1 to 4 configured as described above are connected to the pump P <b> 1 through the neutral flow path 8 and the parallel path 9. Accordingly, when each of the switching valves 1 to 4 is in the neutral position, the oil discharged from the pump P1 is guided to the tank T via the neutral flow path 8, but when the switching valves 1 to 4 are switched, the parallel operation is performed. Pressure oil is supplied to each switching valve 1 to 4 through the passage 9.

  Further, the switching valves 10 to 13 are connected to the pump P2, but the right traveling switching valve 10 for controlling the right traveling motor M1 in order from the upstream side, the boom switching valve 11 for controlling the boom cylinder 5, An arm second speed switching valve 12 for controlling the second speed of the arm cylinder 6 and a bucket switching valve 13 for controlling the bucket cylinder 7 are provided. Each of the switching valves 10 to 13 thus configured is connected to the pump P <b> 2 via the neutral flow path 14. Therefore, when each of the switching valves 10 to 13 is in the neutral position, the oil discharged from the pump P2 is guided to the tank T via the neutral flow path 14.

  The right travel switching valves 1 and 10 are connected in parallel to the right travel motor M1, the boom switching valves 2 and 11 are connected in parallel to the boom cylinder 5, and the arm second speed switching valve 3 is connected. , 12 are connected in parallel to the arm cylinder 6, and the bucket switching valves 4, 13 are connected in parallel to the bucket cylinder 7.

  Moreover, although the switching valves 15-18 are connected to the said pump P3 which comprises the other traveling pump system of this invention, the left traveling switching valve 15 which controls the left traveling motor M2 in order from the upstream side, A turning switching valve 16 for controlling the turning motor 19, a boom second speed switching valve 17 for controlling the second speed of the boom cylinder 5, and an arm switching valve 18 for controlling the arm cylinder 6 are provided.

  The travel straight valve V is connected to the connection process between the pump P3 and the left travel switching valve 15. One inflow port 20 of the travel straight valve V is connected to the pump P2, and the other inflow port is connected. 21 is connected to the pump P3. Of the outflow ports 22 and 23 of the straight travel valve V, one outflow port 22 is connected to a parallel passage 24 connected to the switching valves 11 to 13, and the other outflow port 23 is connected to the left travel switching valve 15. And the neutral flow path 25 that connects the switching valves 15 to 18.

  Further, the pump P3 is connected to a parallel passage 26 branched from the upstream side of the traveling straight valve V, and is connected to the switching valves 15 to 18 via the parallel passage 26. In the process of communicating from the parallel passage 26 to the left travel switching valve 15, a throttle 27 and a check valve 28 that allows only the flow from the parallel passage 26 to the left travel switching valve 15 are provided.

  Further, the switching valves 29 to 32 are connected to the pump P4. From the upstream side, the left travel switching valve 29 for controlling the left traveling motor M2, the swing switching valve 30 for controlling the swing motor 19, and the boom. A boom second speed switching valve 31 for controlling the cylinder 5 at second speed and an arm switching valve 32 for controlling the arm cylinder 6 are provided. Each of the switching valves 29 to 32 thus configured is connected to the pump P4 via the neutral flow path 33 and the traveling straight valve V at the normal position. Therefore, when the straight travel valve V is in the normal position and each of the switching valves 29 to 32 is in the neutral position, the oil discharged from the pump P4 is guided to the tank T via the neutral flow path 33. Further, the pump P4 is also connected to the switching valves 29 to 32 via the parallel passage 34.

  The left travel switching valves 15 and 29 are connected in parallel to the left travel motor M2, the turning switching valves 16 and 30 are connected in parallel to the turning motor 19, and the boom second speed switching valve 17 is connected. , 31 are connected in parallel to the boom cylinder 5, and the arm switching valves 18, 32 are connected in parallel to the arm cylinder 6.

  In the straight travel control device as described above, the straight travel valve V is maintained in the illustrated normal position during normal travel. Accordingly, the discharge amounts of the pumps P1, P2 are supplied to the right travel motor M1 via the right travel switching valves 1, 10, and the discharge amounts of the pumps P3, P4 are supplied to the left travel motor M2. , 29. Accordingly, the right flow motor M1 is supplied with the total flow rate from both the pumps P1 and P2 via the right travel switching valves 1 and 10, and the left travel motor M2 is both left and right from both pumps P3 and P4. A total flow rate is supplied via the travel switching valves 15 and 29.

  The oil discharged from the pump P1 is supplied to the boom switching valve 2, the arm second speed switching valve 3 and the bucket switching valve 4 via the parallel passage 9, and the pump P2 discharge oil passes through the straight travel valve V. Via the parallel passage 24, the parallel passage 24 is supplied to the boom switching valve 11, the arm second speed switching valve 12, and the bucket switching valve 13. Accordingly, the boom cylinder 5 is supplied with the total flow rate via the boom switching valves 2 and 11, and the arm cylinder 6 is supplied with the total flow rate via the arm second speed switching valves 3 and 12. Is supplied with the total flow rate via the bucket switching valves 4 and 13.

Further, the discharge oil of the pump P3 is supplied to the turning switching valve 16, the boom second speed switching valve 17 and the arm switching valve 18 through the parallel passage 26. The oil discharged from the pump P4 is supplied to the turning switching valve 30 and the boom second speed switching valve 31 via the parallel passage 34.
Therefore, the total flow rate is supplied to the turning motor 19 via the switching valves 16 and 30 for turning, the total flow rate is supplied to the boom cylinder 5 via the switching valves 17 and 31 for the second boom speed, and the arm cylinder 6 is supplied. Is supplied with the total flow rate via the arm switching valves 18 and 32.

  On the other hand, when the traveling straight valve V is switched from the illustrated normal position to the switching position on the left side of the drawing, one inflow port 20 and the other outflow port 23 communicate with each other, and the other inflow port 21 and one outflow port 22 communicate with each other. Communicate.

Accordingly, the discharge amount of the pump P2 is divided and supplied to the right travel switching valve 10 and the left travel switching valve 15, and the discharge amount of the pump P3 is directly supplied to the parallel passage 26, and the travel straight travel valve V is set. Via the parallel passage 24.
At this time, the pump P1 is connected to the right travel motor M1 via the right travel switching valve 1, and the pump P4 is connected to the left travel motor M2 via the left travel switching valve 29.

  As is apparent from this, when traveling straight, the discharge amount of the pump P2 is divided into the right travel switching valve 10 and the left travel switching valve 15, but the discharge amounts of the pump P1 and the pump P4 travel as they are. Since the motors M1 and M2 are supplied, the rate of decrease in the flow rate supplied to both the traveling motors M1 and M2 is smaller than in the conventional case. Therefore, it is possible to reduce the shock at the time of the straight traveling switching.

  Further, when the load pressure of the actuator connected to the switching valves 16 to 18 other than the left travel switching valve 15 is high, the pressure oil supplied to the actuator is switched to the left travel via the check valve 28 and the throttle 27. Can be turned to valve 15.

  Ideal for large construction machines.

P1-P4 Pump M1 Right travel motor 1, 10 Right travel switching valve M2 Left travel motor 15, 29 Left travel switching valve V Travel straight valve 26 Parallel passage 27 Restriction 28 Check valve

Claims (3)

  One pump system comprising a pair of pumps as one set is provided, one pump system being one of the left and right traveling pump systems, and the other pump system being either the left or right traveling pump system The travel switching valve is individually connected to each pump of one of the traveling pump systems, and the traveling switching valve is connected in parallel to either the left or right traveling motor, and the other The travel switching valve is individually connected to each pump of the traveling pump system, and the traveling switching valve is connected in parallel to either the left or right traveling motor, while the other traveling pump is connected. A traveling straight valve is connected to a connection process between one pump in the system and the traveling switching valve connected thereto, and one pump in the one traveling pump system is connected to the traveling straight valve. One traveling pump valve is connected to the other traveling pump system, and when the traveling straight valve is in the normal position, the one traveling pump system controls the other traveling motor with the one pump in the other traveling pump system. When the travel straight valve is in the switching position, one travel switching valve for controlling one travel motor and the other travel switching valve are connected to the other travel switching valve. In parallel with one travel switching valve that controls the travel motor, the communication between one pump in the other travel pump system and the travel switch valve that controls the other travel motor is cut off. A straight running control device configured to perform.   A switching valve for controlling another actuator is connected to the downstream side of the switching valve connected to each pump in both pump systems, and the switching valve connected to each pump in one traveling pump system is connected to a specific actuator. On the other hand, the switching valve connected in parallel to each pump in the other traveling pump system is connected in parallel to a specific actuator, while the traveling straight valve is connected to one of the pumps when it is in the normal position. One of the pumps in the traveling pump system is connected in parallel with a traveling switching valve connected to the pump and a switching valve connected to the downstream side of the traveling switching valve, and the other traveling pump system The one of the pumps is directly connected to the switching valve for traveling that controls the other traveling motor, and when the traveling straight valve is in the switching position, One pump in the row pump system communicates in parallel with one traveling switching valve that controls one traveling motor and one traveling switching valve that controls the other traveling motor, and the other The downstream side of the travel switching valve connected to one pump in the one traveling pump system by blocking communication between one pump in the traveling pump system and the traveling switching valve that controls the other traveling motor The travel straight-ahead control device according to claim 1, wherein the travel straight-ahead control device is configured to communicate with the switching valve.   A switching valve for controlling another actuator is connected to a downstream side of the traveling switching valve for controlling the other traveling motor, and the one pump in the other traveling pump system is connected to another actuator via a parallel passage. A check valve that allows only the flow from the parallel passage to the travel switching valve from the parallel path and the parallel travel path, and the travel switching valve that controls the other travel motor. The straight traveling control device according to claim 2, wherein the straight traveling control device is in communication with each other.

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