JPH0577815B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a hydraulic system for supplying pressure oil mainly to auxiliary working machines, such as breakers, in construction machines such as bucket hoes.

BACKGROUND OF THE INVENTION In construction machines such as box hoes, in addition to standard working machines such as traveling hydraulic motors and excavators, auxiliary working machines such as hydraulic breakers can be used by connecting them to the hydraulic circuit. As an example of such a device, another selective switching valve is provided between a switching valve that switches pressure oil to a working machine and a part of the actuator of the working machine. There is a system in which the pressure oil to some actuators of the auxiliary work machine and the actuator of the auxiliary work machine can be selectively switched (see Japanese Utility Model Application Publication No. 59-69262). That is, when using an auxiliary work machine, first connect the auxiliary work machine to the hydraulic circuit, then switch the selection switching valve to the auxiliary work machine side, and then operate the switching valve that operates the standard work machine. The auxiliary working machine is then operated.

However, in such a structure, the discharge pressure oil of one hydraulic pump is used to supply the pressure oil of the unused standard work machine to the auxiliary work machine.In other words, even when the auxiliary work machine is used, one hydraulic pump is used. Since only a large amount of oil is used, in the case of a large-capacity working machine, there is a problem that the amount of oil is insufficient and sufficient working capacity cannot be achieved. Therefore, as a means to solve such problems, conventionally when using high-powered auxiliary work equipment,
This system is designed to combine and supply pressure oil from multiple hydraulic pumps.

Problems to be Solved by the Invention However, with the above-mentioned conventional device that allows pressure oil to merge, when using an auxiliary work machine, pressure oil can only be supplied in a merged state. Even in the case of a small-capacity breaker that can be used, there is a drawback that the oil discharged from the hydraulic pump that was supplying to another working machine is supplied. In addition, with conventional equipment, such merging when using auxiliary work equipment can only be used for devices that flow pressure oil in one direction, such as breakers, and cannot be used for actuators that move reciprocatingly, such as cylinders. There were other drawbacks. The present invention seeks to overcome these conventional drawbacks.

Means for Solving the Problems In order to solve the above problems, the present invention provides a hydraulic system that includes a plurality of hydraulic pumps and supplies pressure oil from the hydraulic pumps to each work machine etc. via a switching valve. In the circuit, in the middle of the hydraulic passage between the switching valve and the boom swing cylinder, a state in which pressure oil from the hydraulic pump is supplied to the boom swing cylinder and a state in which it is supplied to other auxiliary work equipment is selectively provided. A selection switching valve that can be switched to It has a switching position for work equipment and a switching position for auxiliary work equipment that requires a small amount of oil, such as a small capacity breaker, and can be used for large capacity auxiliary work that requires a large amount of oil. When switching to the machine side,
In conjunction with the switching operation of the selection switching valve, automatic switching is performed so that pressure oil from one or more hydraulic pumps other than the above-mentioned partial hydraulic pumps is also combined and supplied to the large-capacity work machine. It is characterized by being equipped with a switching valve.

Embodiments Hereinafter, the configuration of the present invention will be explained based on the illustrated embodiments implemented in a full-swing type excavator.
In FIG. 2, the whole of this type of full-swing type vacuum hoe is shown, and in the figure, 61 is an undercarriage body equipped with a crawler traveling device 62, and an upper revolving body 63 is mounted on the upper part of this undercarriage body 61. Equipped to rotate freely. Reference numeral 71 denotes a blade as a standard working machine, which is attached to the lower traveling body 61. On the other hand, the upper revolving body 63 is also equipped with an excavator 64 as a standard working machine. This excavator 64 consists of a boom 65 pivotally attached to an upper revolving structure 63, an arm 66 pivotally attached to the tip of the boom 65, a bucket 67 also pivoted to the tip of the arm 66, and 68 is a boom. 65 is the boom up and down cylinder that moves up and down, 69 is the arm 6
6 is an arm cylinder that rotates, and 70 is a bucket cylinder that rotates a bucket 67.

FIG. 1 shows a hydraulic circuit that supplies pressure oil to machine working machines 64, 71, etc. In the figure, 6, 9, 10 are
Three hydraulic pumps driven by the engine 11 are shown, and these hydraulic pumps 6, 9, 1
0, two first and second hydraulic pumps 6, 9
A first switching valve 12 is disposed in the passage on the discharge side. This first switching valve 12 switches the pressure oil to a standard working machine, etc. For example, when this first switching valve 12 is switched, the excavating working machine 6
Pressure oil is selectively supplied to the arm cylinder 69 of No. 4, the bucket cylinder 70, the left and right travel hydraulic motors, the cylinder 68 of the boom 65, the swing cylinder, etc., and the flow of pressure oil to each of these actuators is controlled. It is designed to be reverse switched. On the other hand, a second switching valve 31 is provided on the discharge side of the other third hydraulic pump 10, and this second switching valve 31 is used for, for example, a rotating motor of an upper rotating structure, a blade working machine, etc. This is used to switch the pressure oil to the cylinders, etc.

1 is a selection switching valve of the present invention, and this selection switching valve 1 is a 4-position switching valve equipped with eight boats, and its four outlet ports 13, 14, 15,
Two outlet ports 13 and 14 of the 16 are connected to the boom swing cylinder 2, and the other two outlet ports 15 and 16 are connected to the boom swing cylinder 2 through a coupler 17.
Auxiliary work equipment is now connected. 3,
4 and 5 indicate actuators of the auxiliary work equipment connected to this coupler 17, 3 indicates a bucket tilt cylinder provided as an option, 4 indicates a small capacity hydraulic breaker, and 5 indicates a large capacity hydraulic breaker. , select these and connect them. Then, when the selection switching valve 1 is switched to the first switching position 18, pressure oil from the first hydraulic pump 6 that supplies pressure oil to the first switching valve 12 side is used for swinging the boom of the excavating machine. It is supplied to the cylinder 2 side. When switching to the second switching position 19 side, the hydraulic pump 6 is also connected to the bucket tilt cylinder 3.
of pressure oil is supplied. Furthermore, a third switching position 20
is for supplying pressure oil from the hydraulic pump 6 to the small capacity breaker 4, while the fourth switching position 21 is used when the large capacity breaker 5 is connected. Each of these breakers 4, 5
third and fourth switching positions 20 for supplying pressure oil to;
21, at the third switching position 20, pressure oil entering from the inlet port 24 connected to the outlet side of the first switching valve 12 is supplied to the inlet side of the small capacity breaker 4 through the oil passage 22. The return oil from the small capacity breaker 4 flows through the oil passage 48 in the selection switching valve 1.
The oil is returned directly to the tank 45 through a return oil path 44. On the other hand, in the fourth switching position 21, as in the third switching position 20, an oil passage 23 supplies pressure oil to the inlet side of the large capacity breaker 5 from an inlet port 24 connected to the outlet side of the first switching valve 12. In addition, the first switching valve 12
It has a merging oil passage 27 for merging pressure oil into this pressure oil supply oil passage 23 from another inlet port 26 that is not communicated with the other side.

8 is an automatic switching valve of the present invention, and a port 28 of this automatic switching valve 8 is connected to the discharge side of the third hydraulic pump 10, and on the other hand, two outlets 29, 30 are connected to the discharge side of the third hydraulic pump 10.
One of them 29 is connected to the inlet side of the second switching valve 31, and the other outlet port 30 is connected to the merging oil passage 27 side at the fourth position from the oil passage 33 having the check valve 25 with the throttle 32. It is adapted to be connected to an inlet port 26. This automatic switching valve 8 is 2
It has two switching positions 49, 50, one position 49
When the switch is switched to , pressure oil from the third hydraulic pump 10 is supplied to the second switching valve 31 side, and the above-described swing operation of the upper revolving body 63 and rotation operation of the blade can be performed. On the other hand, when switching to the other position 50, pressure oil from the third hydraulic pump 10 is supplied to the merging oil passage 27 side through the oil passage 33. Further, an oil passage 33 connecting the inlet port 26 of the merging oil passage 27 and the outlet port 30 of the automatic switching valve 8 is provided.
A pilot pressure oil passage 7 for supplying pilot pressure which branches off from the oil passage 33 and switches the automatic switching valve 8 is formed in the middle.

In the above configuration, when there is no pressure oil in the pilot pressure passage 7 that switches the automatic switching valve 8,
This automatic switching valve 8 is in a state where it is switched to a position 49 where pressure oil is supplied to the second switching valve 31 side.
Therefore, under normal conditions, the second switching valve 31 is operated to transfer the pressure oil of the third hydraulic pump 10 to the upper rotating structure 6.
It can be used for turning operations and blade operations. In this state, when the selection switch 1 is operated to switch to the fourth switching position 21 and the swing operating tool 51 is operated in order to supply pressure oil to the large capacity breaker 5, the pressure oil from the first switching valve 12 is However, pressure oil is supplied to the breaker 5 through the hydraulic pressure supply path 23 in the selection switching valve 1, but at the same time, since the automatic switching valve 8 is not switched in this state, the pressure oil is supplied to the merging oil path 27 side. Pressure oil is not supplied from the automatic switching valve 8 side, and therefore, pressure oil from the first hydraulic pump 6 side flows in the opposite direction from this merging oil passage 27 and returns to the tank 45 through the throttle 32. . At this time, aperture 3
2, the pressure in the oil passage 33 increases. This pressure oil is supplied from the pilot pressure oil passage 7 to the automatic switching valve 8 to switch the movable switching valve 8. Therefore, the pressure oil of the third hydraulic pump 10 also flows from the oil passage 33 to the pressure oil supply passage 23 through this merging oil passage 27, and the first hydraulic pump 6 and the third hydraulic pump 10
Pressure oil is supplied to the large-capacity breaker 5 in a state where the pressure oils are combined. In this state where the automatic switching valve 8 is switched, the pressure oil of the third hydraulic pump 10 is also supplied to the pilot pressure passage 7 side, so the automatic switching valve 8 is self-maintained in the switched state.

Reference numeral 41 indicates a switching lever as an operating tool for the selection switching valve 1, and in this embodiment, the switching lever 41 is used to operate the swing cylinder 2 of the boom. Of course, this switching lever 41 has the advantage of being able to select from four positions: a position for operating the bucket tilt cylinder 3, a position for operating the small capacity breaker 4, and a position for operating the large capacity breaker 5. It may be replaced with a pedal or other operating tool. In this case, when using the auxiliary work machines 3, 4, and 5, the swing cylinder 2 cannot be used, but since there are few opportunities to use these at the same time,
There are no particular inconveniences in this way. Further, in this case, the operating tool 51 that swings the boom regardless of the position of the selection switching valve 1, that is, the operating tool 51 is provided on the first switching valve 12 side.
With this operating tool 51 for operating the swing boom,
The pressure oil of the tilt cylinder 3 and each of the breakers 4 and 5 can be operated. Various mechanisms for interlocking the automatic switching valve 8 and the selective switching valve 1 can be considered, such as electrically detecting the switching position of the selective switching valve 1, for example.

Effects of the Invention As described above, according to the present invention, when the selection selector valve is switched to supply pressure oil to the working machine that requires a large amount of oil, the pressure oil from other hydraulic pumps is also merged. Since pressure oil is supplied to this large-capacity working machine, a sufficient amount of oil is supplied to the working machine, and the capacity of the working machine can be fully utilized.
In particular, with this invention, not only when using such a large-capacity breaker, but also when using a small-capacity, good-quality breaker, it is sufficient to simply switch the selection selector valve to that position. This has the effect of making it easy to obtain the required amount of oil. Moreover, switching between the auxiliary work equipment and the normal work equipment and switching between merging and non-merging can be performed with a single selection selector valve, making the operation easy and allowing multiple such operations to be performed. Compared to the switching valve used in the above, it does not require the space around the driver's seat to be narrowed by arranging multiple operating levers on the driver's seat, and the structure is simple. The selection switching valve also has a switching position for reciprocating actuators such as pressure oil cylinders, so auxiliary work equipment equipped with such actuators can be used simply by switching the selection switching valve. There are advantages to doing so. Furthermore, in this invention, since the pressure oil of the boom swing cylinder is supplied to the auxiliary work machine, the auxiliary work machine can be operated with the operation pedal for the boom cylinder, allowing efficient operation. .

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram of a construction machine showing an embodiment of the present invention, and FIG. 2 is an overall side view of a backhoe. 1... Selection switching valve, 2... Boom swing cylinder, 3... Tilt cylinder, 4... Small capacity breaker, 5... Large capacity breaker, 6, 9, 10...
...Hydraulic pump, 7...Pilot pressure oil line, 8...
Automatic switching valve.

Claims (1)

[Claims] 1. In a hydraulic circuit equipped with a plurality of hydraulic pumps and configured to supply pressure oil from the hydraulic pumps to each work machine, etc. via a switching valve, a hydraulic passageway between the switching valve and the boom swing cylinder is provided with a selection switching valve that can selectively switch between supplying pressure oil from the hydraulic pump to the boom swing cylinder and supplying it to other auxiliary work equipment; switching positions for auxiliary working machines that perform reciprocating movements such as
It has a switching position for auxiliary work equipment that requires a large amount of oil, such as a large capacity breaker, and a switching position for auxiliary work equipment that requires a small amount of oil, such as a small capacity breaker. When the selection switching valve is switched to the side of a large capacity auxiliary work machine that requires a large amount of oil, in conjunction with the switching operation of the selection switching valve,
A construction machine characterized by being provided with an automatic switching valve that switches to combine pressure oil from one or more hydraulic pumps other than the above-mentioned part of the hydraulic pumps and supply the same to the large-capacity work machine. hydraulic system.