JP2624268B2 - Hydraulic drive for construction machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic drive device for construction equipment, and more particularly to a hydraulic drive device suitable for a shovel excavator.

2. Description of the Related Art In a hydraulic drive system for construction equipment, a first and second valve groups each including a plurality of directional switching valves connected in tandem, and a directional switching valve in each of the valve groups. A hydraulic cylinder and a hydraulic motor are connected to each other, and a hydraulic pump is connected to each of the valve groups to supply hydraulic oil to these hydraulic actuators. It is already known that the hydraulic motor is connected to a directional control valve located downstream of the hydraulic cylinder in the second valve group, and is connected to a directional control valve located upstream of the cylinder.
However, this hydraulic drive device cannot travel by a hydraulic motor when a boom, an arm, and a bucket constituting a front attachment are driven by a hydraulic cylinder.

As another hydraulic drive for construction machinery, for example,
In 57-192568, two sets of valve groups having a plurality of directional control valves are provided, the directional control valves in each valve group are connected in parallel, and a plurality of hydraulic actuators and hydraulic pumps including a hydraulic motor and a hydraulic cylinder are provided. Are connected to the directional control valves of each of the valve groups, and a hydraulic motor for driving the two valve groups is connected to the directional control valves associated therewith via a two-position directional control valve. ,
By operating the two-position switching valve, it is possible to receive the supply of hydraulic oil from the hydraulic pump connected to one valve group, and to operate the hydraulic actuator connected to the other valve group. Even so, the hydraulic motor can be rotated by operating the two-position switching valve.

[Problems to be solved by the invention]

The latter hydraulic drive device can simultaneously operate a hydraulic cylinder connected to one valve group and simultaneously rotate a hydraulic motor connected to both valve groups. , While driving the boom and the arm. However, traveling can only be regarded as straight traveling, and steering cannot be performed.

SUMMARY OF THE INVENTION An object of the present invention is to provide a hydraulic drive device for a construction machine that can perform not only a straight traveling but also a steering while driving a boom and an arm.

[Means for solving the problem]

Each of a first valve group including a plurality of directional switching valves connected to a tandem, a second valve group including a plurality of directional switching valves connected to a tandem, and each of the valve groups Hydraulic actuators connected to each of the directional control valves and including hydraulic actuators for traveling, and hydraulic pumps connected to each of the valve groups for supplying hydraulic oil to these hydraulic actuators Has,
The traveling hydraulic actuator for the first valve group is connected to the direction switching valve located on the most upstream side of the other hydraulic actuators, and the traveling hydraulic actuator for the second valve group is located on the most downstream side of the other hydraulic actuators. In the hydraulic drive device of the construction machine connected to the directional switching valve, when the construction machine performs a traveling operation and a work operation at the same time, the traveling hydraulic actuator connected to the second valve group is operated by the first valve. The first switching valve is connected to the hydraulic pump connected to the group via the first switching valve, and the first switching valve and the traveling hydraulic actuator connected to the second valve group are connected to the second switching valve. Discharge oil from a hydraulic pump connected to the first valve group to a traveling hydraulic actuator connected to the second valve group by an intervening first switching valve It was supplied, further in the direction of the hydraulic oil flow was so changed by the second switching valve.

An embodiment of the hydraulic drive device for construction machines of the present invention will be described below with reference to the accompanying drawings.

〔Example〕

The drawings show a hydraulic drive circuit for a hydraulic shovel, wherein reference numerals 11 and 12 are hydraulic motors for rotating left and right drive sprockets in the traveling device, 13 is a hydraulic cylinder for rotating a boom constituting a front attachment, and 14 is a front A hydraulic cylinder that rotates the arm in the attachment, 15 to 20 are directional switching valves,
Reference numerals 21 and 22 indicate hydraulic pumps, respectively. In addition,
In the drawing, a hydraulic cylinder for driving the bucket and a circuit for controlling the operation of the hydraulic cylinder are omitted.

Each of the directional valves 15 to 20 is a four-port three-position switching spool valve connected to the ABR, and
A port is provided for bypassing hydraulic oil when the spool is in the neutral position. Of these directional control valves, directional control valves 15 to 17 are connected in tandem to form one set of valve groups, and directional control valves 18 to 20 are also connected in tandem to form another set of valve groups. ing.

The directional control valves 15 to 17 are connected to each other by bypass ports, and the P port is connected to a pipeline connecting the bypass ports via a check valve, and the directional control valves 18 to 20 are bypassed to each other. Connect ports, P
The port is connected to the line connecting the bypass port via a check valve. The pipeline connecting the bypass ports of the directional switching valves 15 to 17 is connected to the hydraulic pump 21, and the pipeline connecting the bypass ports of the directional switching valves 18 to 20 is connected to the hydraulic pump 22, respectively. R of valve
The ports are respectively connected to the oil tanks via a common pipeline, the A and B ports of the directional switching valve 15 are connected to the hydraulic motor 11, the A and B ports of the directional switching valve 20 are respectively connected to the hydraulic motor 12, and the directional switching valve A and B ports of 16, 19 are connected to hydraulic cylinder 13,
The A and B ports of the directional valves 17 and 18 are connected to the hydraulic cylinder 14, respectively.

In these direction switching valves 15 to 20, the movement of the spool is performed by a hydraulic pump 23, a relief valve 24, and pilot valves 25 to 28 shown at the top of the drawing. Each of these pilot valves has a structure in which the two pressure reducing valves are opened and closed by turning an operation lever. The pilot valve 25 has a pressure reducing valve 30, 31 whose outlet side port is connected to the pilot port of the direction switching valve 15, and whose pump side port is connected to the hydraulic pump 23. The spool of the direction switching valve 15 is moved by increasing or decreasing the pressure of the operating oil flowing from the hydraulic pump 23 to the direction switching valve 15 in proportion to the amount of rotation of the lever by operating the lever 31. Similarly, the pilot valve 26 has the pressure reducing valves 33 and 34 connected to the hydraulic pump 23 and the pilot port of the direction switching valve 20, and operates the pressure reducing valves 33 and 34 by the rotation of the operation lever 35. 20 spools can be moved. In addition, pilot valve
27 also has pressure reducing valves 35 and 36 connected to the pilot ports of the direction switching valves 16 and 19, and by rotating the operation lever 37, the spools of the direction switching valves 16 and 19 can be moved. I have. The pilot valves 28 and 39 are connected to the pilot ports of the directional control valves 17 and 18, respectively, and the operation lever 40 is rotated so that the spools of the directional control valves 17 and 18 can be moved. ing.

In this hydraulic drive device, one hydraulic pump 21
Are connected to a valve group formed by the direction switching valves 15 to 17 via the switching valve 41, and the hydraulic motor 12 is connected to the switching valve 41 via the switching valve 42. Of these switching valves, the switching valve 41 is a pilot-operated two-position switching valve, the inlet port of which is connected to the hydraulic pump 21, and the outlet port of which is a bypass port of the directional switching valves 15 to 17. Are connected to the pipeline connecting the two. The switching valve 42 is a pilot-operated three-position switching valve, and the inlet port is connected to the switching valve 41.
The outlet port is connected to the hydraulic motor 12.

The movement of the spools of the switching valves 41 and 42 is controlled by the pilot valves 25 to 28.
The pilot valves 27, 2
In connection with the operation of 8, the switching valve 43 is switched, and the hydraulic pump 23
The discharge oil from the pump is guided to the switching valve 41 so that the switching valve 41
Of the spool. For this purpose, a shuttle valve 45 is provided at an outlet side port of the switching valves 30 and 31 in the pilot valve 25, and a switching valve in the pilot valve 25 is provided.
Shuttle valves 46 are connected to outlet ports of 33 and 34, respectively. Shuttle valves 48 are connected to outlet ports of switching valves 35 and 36 of pilot valve 27, and outlet ports of switching valves 38 and 39 of pilot valve 28. Is connected to a shuttle valve 49, respectively. The switching valve 43 has a shuttle valve 4 at the inlet port.
4, 45 are connected via a shuttle valve 44, and the pilot port is connected to shuttle valves 48, 49 via a shuttle valve 47. The switching valve 41 has a pilot port connected to the outlet side port of the switching valve 43, and is switched by the discharge oil from the hydraulic pump 23 passing through the pilot valves 25 and 26 when the pilots 27 and 28 are operated. It is made to be. The switching valve 42 has a pilot port connected to the outlet ports of the switching valves 33 and 34 in the pilot valve 26, and when the pilot valve 26 is operated, the movement of the spool is performed by the discharge oil from the hydraulic pump 23. It is made to.

In this hydraulic drive device, when only the pilot valve 25 is operated, the oil discharged from the hydraulic pump 23 is supplied to the direction switching valve 15.
To the pilot port, the spool of the direction switching valve 15 moves, and the oil discharged from the hydraulic pump 21
And only the hydraulic motor 11 is rotated, so that the hydraulic shovel can be steered to the right, for example. When only the pilot valve 26 is operated, the hydraulic pump 23
From the directional control valve 20, the spool of the directional control valve 20 moves,
Is supplied to the hydraulic motor 12, and the hydraulic shovel can be steered, for example, to the left.

When the pilot valve 25 and the pilot valve 26 are simultaneously operated, the discharge oil from the hydraulic pump 23 is guided to the directional switching valves 15 and 20, and the spools of these directional switching valves are moved to discharge the oil from the hydraulic pump 21. Oil is supplied to hydraulic motor 11, hydraulic pump
Discharge oil from 22 is supplied to the hydraulic motors 12, respectively, so that the hydraulic shovel can move forward. When the pilot valves 25 and 26 are simultaneously operated in the opposite directions, the spools of the direction switching valves 15 and 20 are moved in the opposite direction, and the flow of the discharge oil from the hydraulic pumps 21 and 22 to the hydraulic motors 11 and 12 is controlled. The direction changes, and the excavator can move backward. In these operations, when the pilot valve 26 is operated, the spool of the switching valve 42 also moves, but the switching valves 41, 43 are switched when the pilot valves 27, 28 are operated. Therefore, the hydraulic motor 11 is supplied with hydraulic oil from the hydraulic pump 21, and the hydraulic motor 12 is supplied with hydraulic oil from the hydraulic pump 22, which satisfies the normal traveling function without being affected by the switching of the switching valve 42. be able to.

When only the pilot valve 27 is operated, the direction switching valve 16,
The spool 19 is moved by the hydraulic pump 23, and the discharge oil from the hydraulic pumps 21 and 22 is supplied to the hydraulic cylinder 13 via these directional switching valves, so that the boom which is a front component can be driven. On the other hand, when only the pilot valve 28 is operated, the spools of the direction switching valves 17 and 18 are moved by the hydraulic pump 23 and the hydraulic pumps 21 and 22 are moved.
Is supplied to the hydraulic cylinder 14 via these direction switching valves, and the arm constituting the front attachment can be driven. In these, when the pilot valves 27 and 28 are operated, the switching valve 43 is also switched, but since the pilot valves 25 and 26 are not operated, the switching valve 41 remains at the neutral position.

Furthermore, the pilot valve 27 is operated, and the hydraulic pump
When the pilot valves 25 and 26 are operated while the hydraulic cylinders 21 and 22 are driving the hydraulic cylinder 13, the directional control valve 15 associated with the pilot valve 25 is at the most upstream position. The hydraulic pump 22 drives the hydraulic cylinder 13 because it is driven and the direction switching valve 20 associated with the pilot valve 26 is the most downstream. However, by operating the pilot valves 25 and 26, the discharge oil from the hydraulic pump 23 is guided to the pilot port of the switching valve 41 via the switching valve 43, and the switching valve 41 is switched. Hydraulic oil having the same pressure as that of the motor 11 is supplied to the hydraulic motor 12 via the switching valve 41 and the switching valve 42, so that the hydraulic shovel can travel straight while driving the boom.

When the pilot valve 28 is operated and the hydraulic pumps 21 and 22 drive the hydraulic cylinder 14, the pilot valves 25 and 2
6 is operated, the directional control valve 15 associated with the pilot valve 25 is the most upstream, so that the hydraulic motor 11
The hydraulic pump 22 is driven by the hydraulic pump 22 because the directional switching valve 20 associated with the pilot valve 26 is the most downstream.
Drive 14 However, by operating the pilot valves 25 and 26, the discharge oil from the hydraulic pump 23 is guided to the pilot port of the switching valve 41 via the switching valve 43, and the switching valve 41 has already been switched. Is a hydraulic motor with respect to the hydraulic motor 12 via the switching valve 41 and the switching valve 42.
By supplying hydraulic oil at the same pressure as that of 11, the hydraulic excavator can make a straight forward run while driving the arm, and the pilot valve 25, 26 is operated in the opposite direction, the switching valve The 42 is also switched, allowing the vehicle to run straight back.

If only the pilot valve 25 is returned while driving the boom and the arm while traveling, the direction switching valve 15
Is in the neutral position, and the hydraulic pump 21 drives the hydraulic cylinder 13 and simultaneously drives the hydraulic motor 12 so that the hydraulic cylinder 13
, The steering with the right crawler can be performed as a hydraulic excavator, and when only the pilot valve 26 is returned, the direction switching valve 20 and the switching valve 42 are in the neutral position, and the oil discharged from the hydraulic pump 21 is Can drive the hydraulic crawler 11 to drive the hydraulic cylinder 14 while steering the left crawler as a hydraulic excavator. Further, by operating the pilot valves 25 and 26 in opposite directions, steering by driving the left and right crawlers is also possible.

〔The invention's effect〕

As described above, the hydraulic drive device for a construction machine according to the present invention includes a first valve group including a plurality of directional switching valves connected in tandem, and a plurality of directional switching devices connected in tandem. A second group of valves comprising valves, a plurality of hydraulic actuators coupled to each of the directional control valves in each of the group of valves and including hydraulic actuators for travel, and hydraulic oil A hydraulic pump connected to each of the valve groups, and the traveling hydraulic actuator for the first valve group is connected to the direction switching valve located on the most upstream side of the other hydraulic actuators, In a hydraulic drive device for a construction machine, a traveling hydraulic actuator for the second valve group is connected to a direction switching valve located on the most downstream side of the other hydraulic actuators. When the machine performs the traveling operation and the work operation at the same time, the traveling hydraulic actuator connected to the second valve group interposes the first switching valve on the hydraulic pump connected to the first valve group. While being connected, the first switching valve and the traveling hydraulic actuator connected to the second valve group are connected via the second switching valve,
The travel switching hydraulic actuator connected to the second valve group is supplied with discharge oil from the hydraulic pump connected to the first valve group by the first switching valve, and the flow direction of the hydraulic oil is changed to the second direction. The switching oil is changed by the first switching valve, so that the first switching valve supplies the hydraulic oil discharged from the hydraulic pump connected to the first valve group to the traveling hydraulic actuator connected to the first and second valve groups. Let me supply
Work and traveling can be performed simultaneously, and the direction of the flow of hydraulic oil supplied to the traveling hydraulic actuator connected to the second valve group is changed by the second switching valve, so that In addition, steering can be performed.

[Brief description of the drawings]

The drawings are hydraulic circuit diagrams showing one embodiment of the hydraulic drive device for construction machines of the present invention.

Claims (1)

(57) [Claims] 1. A first group of valves having a plurality of directional valves connected in tandem, and a second group of valves having a plurality of directional valves connected in tandem. A plurality of hydraulic actuators connected to each of the directional switching valves in each of the valve groups and including hydraulic actuators for traveling, and connected to each of the valve groups to supply hydraulic oil to these hydraulic actuators The traveling hydraulic actuator for the first valve group is connected to the direction switching valve located on the most upstream side of the other hydraulic actuators, and the traveling hydraulic actuator for the second valve group is connected to the other hydraulic pump. In a hydraulic drive for a construction machine connected to a direction switching valve located on the most downstream side of the hydraulic actuator, the construction machine performed a traveling operation and a work operation simultaneously. The traveling hydraulic actuator connected to the second valve group is connected to the hydraulic pump connected to the first valve group via the first switching valve, and the first switching valve; The traveling hydraulic actuator connected to the second valve group is connected to the traveling hydraulic actuator connected to the second valve group by the first switching valve, and the first hydraulic valve is connected to the traveling hydraulic actuator connected to the second valve group by the first switching valve. A hydraulic drive device for a construction machine, wherein a discharge oil from a hydraulic pump connected to a valve group is supplied, and a flow direction of the hydraulic oil is changed by a second switching valve.