JP3410365B2 - Hydraulic circuit of construction machinery that can use crusher etc. - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a hydraulic circuit of a construction machine in which a preliminary work machine such as a crusher can be used.

[0002]

2. Description of the Related Art In construction machines such as hydraulic excavators,
When excavating earth and sand, etc., attach the bucket to the work implement attachment and use it. Also, when crushing rocks, etc., the crusher should be attached to the work machine attachment before use. In addition, a breaker should be installed when drilling a concrete wall. In this way, work tools are attached and used according to the purpose of work. All of these working tools are hydraulically driven, but the required driving force differs depending on the working tools.

For example, a crusher requires a large amount of pressure oil in order to operate at high speed during crushing. On the other hand, the breaker does not require a large amount of pressure oil. Therefore, it is possible to provide a hydraulic circuit for each working tool, but if a hydraulic circuit is provided for each working tool, the hydraulic circuit becomes complicated and the cost increases, and the effective use of pressure oil from the hydraulic pump is not possible. Can not. Therefore, conventionally, a merging circuit for merging pressure oils from a plurality of hydraulic pumps has been used, if necessary.

FIG. 3 shows a conventional hydraulic circuit, which is a circuit disclosed in Japanese Patent Laid-Open No. 8-199632. In FIG. 3, the center oil passage 12 of the first hydraulic pump 11 is provided with a direction switching valve 14 for a traveling hydraulic motor 13, a preliminary direction switching valve 15 for connecting a crusher, etc.
The direction switching valve 17 of the boom cylinder 16, the direction switching valve 19 of the arm cylinder 18, the direction switching valve 21 of the turning hydraulic motor 20, and the oil tank T are sequentially connected, and the center oil passage 24 of the second hydraulic pump 23 is used for traveling. Direction switching valve 26 of hydraulic motor 25, direction switching valve 28 of bucket cylinder 27, direction switching valve 29 of boom cylinder 16, arm cylinder 1
The merging direction switching valve 30 of 8 and the on-off valve 17 are sequentially connected.

Further, a branch oil passage 32 is provided from the upstream side of the opening / closing valve 31 of the center oil passage 24 to join the input oil passage of the preliminary direction switching valve 15. The output side pilot oil passages 34a and 34b of the remote control valve 33 are connected to the pilot port of the preliminary directional control valve 15, and one side 34a of the pilot oil passage 34 is connected.
Is provided with a branch oil passage 35, and is connected to the pilot port of the opening / closing valve 17 via the pilot passage opening / closing valve 36. An oil passage 39 is connected to the pilot port of the passage opening / closing valve 36,
The oil passage 39 is connected to the auxiliary hydraulic pump 38 via the electromagnetic switching valve 37.
It is connected to the. The solenoid of the electromagnetic switching valve 37 is connected to the power source via the switch 40.

The output port of the spare directional control valve is the oil passage 41.
It is connected to the stop valves 42 and 43 by a and 41b. A switching valve 44 is inserted in the oil passage 41b, and the switching valve 44
The pilot port of is connected to the branch oil passage 45 from the oil passage 39. A crusher 50 shown in FIG. 4 or a breaker 55 shown in FIG. 5 is connected downstream of the stop valves 42 and 43.
The crushing machine 50 has a pair of crushing claws 51, 51.
1 is rotatably attached by a support shaft 52, and a crusher hydraulic cylinder 53 is connected to the base end side of the support shaft 52.
The crushing claw 51 is driven by the crusher hydraulic cylinder 53.

In the breaker 55, a cylinder is formed in a breaker body 56, a piston rod 57 is slidably provided in the cylinder, and a striking is applied by reciprocating the piston rod 57.

When the crusher 50 is mounted and operated in this conventional circuit, it functions as follows. When the crusher 50 is attached, the switch 48 is turned on (closed). When the switch 48 is turned on, a solenoid current flows, the electromagnetic switching valve 37 is switched to the state (b), and the pilot pressure from the auxiliary hydraulic pump 38 is piloted to the pilot port of the passage opening / closing valve 36 and the pilot port of the switching valve 44. Pressure oil flows. As a result, the oil passages 34a and 35 are communicated with each other, and the on-off valve 31 is switched to the closed state. On the other hand, the switching valve 44 switches to the state (b), and the oil passage 41b and the stop valve 43 communicate with each other.

When the remote control valve 33 is operated in the closing direction of the crusher (left side in the drawing), pilot pressure oil flows in the oil passage 34a, the preliminary direction switching valve 15 is switched to the state (b), and the first hydraulic pump 11 is operated. The pressure oil is supplied to the oil passage 41a, and the crusher 50 operates in the closing direction. Further, the pilot oil pressure flows through the oil passage 35 to the pilot port of the on-off valve 31, and the on-off valve is switched to the closed state. As a result, the pressure oil from the second hydraulic pump 23 joins the center oil passage 24, the upstream of the on-off valve 31 and the branch oil passage 32 to the input oil passage of the preliminary switching control valve 15, and the second oil pressure. The pressure oil of the pump 23 is also supplied to the oil passage 41a. Therefore, the speed in the closing direction of the crusher 50 is accelerated.

When the remote control valve 33 is operated in the opening direction of the crusher (on the right side of the drawing), pilot pressure oil does not flow in the oil passage 35, so the on-off valve 31 is switched to the communicating state and the second
The pressure oil from the hydraulic pump 23 flows to the oil tank T through the center oil passage 24, and the speed in the opening direction of the crusher 50 is operated only by the pressure oil of the first hydraulic pump 11, and the second hydraulic pump 2
It is not accelerated by the pressure oil of 3. Also, the breaker 55
Since the switch 48 is turned off (opened) when the engine is mounted, the pressure oil of the second hydraulic pump 23 is stored in the preliminary direction switching valve 15
Do not join

As described above, in the conventional circuit 1, when the crusher is operated in the closing direction, the pressure oil of the first and second hydraulic pumps 11 and 23 joins the crusher hydraulic cylinder 53. It can flow in and increase the closing speed of the crusher to exert the functions of the crusher. However, if the boom cylinder 16 or the arm cylinder 18 is operated while the crusher is in use, the speed is not increased and the operation of the crusher becomes unstable.

FIG. 6 shows another conventional circuit (hereinafter referred to as conventional circuit 2). The conventional circuit 2 will be described below. In FIG. 6, the preliminary switching control valve 53 and the arm first switching control valve 54 are sequentially connected to the center oil passage 52 of the second hydraulic pump 51. The output port of the preliminary switching control valve 53 is connected via a flow path switching circuit 55 to stop valves 56 and 57 that connect a crusher or a breaker. When using a breaker, the flow path switching circuit 55 may intrude dust, foreign matter, etc. from the outside, and the return oil from the discharge port does not go through the preliminary switching control valve 53 but goes directly to the hydraulic oil tank via the filter. It is a circuit for returning. Also, the arm first switching control valve 5
An arm cylinder 59 is connected to the output port of No. 4.

An arm second switching control valve 63 is connected to the center oil passage 62 of the first hydraulic pump 61. The arm second switching control valve 63 is connected to the input side of the arm first switching control valve 54 through the branch oil passage 64 provided on the input side by blocking the oil passage between the input and output ports. It joins the pressure oil. Therefore, the arm second switching control valve 63 has an oil passage between the input and output ports configured to close the center oil passage 62 and the input oil passage branched from the center oil passage 62 when the pilot hydraulic pressure acts on the pilot port. . The pilot ports of the arm first switching control valve 54 and the arm second switching control valve 63 are connected to one arm remote control valve 65.
By operating 5, the pressure oil of the first hydraulic pump 61 is changed to the second pressure oil.
The arm cylinder 59 is joined by the pressure oil of the hydraulic pump 51.
To operate.

A branch oil passage 67 is provided upstream of the center oil passage 62 of the first hydraulic pump 61, and this branch oil passage 67 is provided upstream of the center oil passage 52 of the second hydraulic pump 51 via a logic valve 68. Have been joined. The logic valve 68 is an opening / closing valve that shuts off or connects the oil passage 67, and is controlled by the control valve 69. That is, when the pilot pressure oil acts on the pilot port of the control valve 69, the logic valve 68 communicates, and when it does not act, it shuts off. As pilot pressure oil, pilot pressure from the auxiliary remote control valve 70 of the auxiliary switching control valve 53 is supplied through the oil passage 81 via the shuttle valve 73 and the electromagnetic switching valve 75.

Output oil passages 71, 72 of the auxiliary remote control valve 70
Is connected to the pilot port of the preliminary switching control valve 53. Further, the shuttle valve 73 is provided between the output oil passages 71 and 72.
And the output of the shuttle valve 73 is connected to the input ports of the pressure switch 74 and the electromagnetic switching valve 75. The pressure switch 74 is turned on (closed) when pilot pressure is applied.
The switch is a normally open switch that is off (open) when not operating. The pressure switch 74 is connected in series with the solenoid of the electromagnetic switching valve 75, the power supply 76, and the crusher selection switch 77 to form an electric closed circuit 78. The output port of the electromagnetic switching valve 75 is connected to the closing side pilot port 63a of the arm second switching valve via the oil passage 79 via the shuttle valve, and is connected to the pilot port of the control valve 69 via the oil passage 81. .

The conventional device 2 functions as follows with the above configuration. That is, when using a crusher, stop valve 5
A crusher is connected to 6, 57 and the crusher selection switch 77 is turned on (closed). When operating the spare remote control valve 70,
Pilot pressure oil appears in the output oil passage 71 or 72, and the pilot oil pressure acts on the pressure switch 74 via the shuttle valve 73 to switch it on. Therefore, a solenoid current flows through the electric closed circuit 78, and the electromagnetic switching valve 75 is switched to the communication side (the lower state in the figure). Therefore, the pilot pressure oil from the shuttle valve 73 simultaneously flows through the oil passage 79, and the shuttle valve 8
0 to the closing side pilot port 63a of the arm second switching control valve 63 to switch to the state a.

Further, the pilot pressure oil flowing through the oil passage 81 flows to the pilot port of the control valve 69, switches to the state A, and brings the logic valve 68 into the communicating state. Therefore, since the arm second switching control valve 63 is shut off, the pressure oil (operating oil) of the first hydraulic pump 61 flows into the branch oil passage 67,
It merges with the upstream of the center oil passage 52 of the second hydraulic pump 51 via the logic valve 68. As a result, the hydraulic oils of the first hydraulic pump 61 and the second hydraulic pump 51 simultaneously flow into the crusher, the operating speed is accelerated, and proper operation can be performed.

When the arm is opened, the pilot pressure oil of the arm remote control valve 65 is changed to the second pressure when the crusher is used.
It flows to the pilot port 63b of the arm switching valve 63.
However, the pilot pressure oil from the auxiliary remote control valve 70 flows into the pilot port 63a as described above. Therefore, the second arm switching control valve 63 is in a neutral state because the pilot pressure oil acts on both pilot ports, the center oil passage of the input / output port communicates, and the pressure oil of the first hydraulic pump is the center oil passage 62. Of the second hydraulic pump and does not join the center oil passage 52 of the second hydraulic pump.

[0019]

As described above, in the conventional circuit 1, when the arm operation or the boom operation is performed while the crusher is in use, the pressure oil acting on the crusher is not increased, and the crusher is crushed. There was a problem that the machine operation became unstable. Further, in the conventional circuit 2, when the arm is opened while the crusher is in use, the center oil passage of the input / output port of the second arm switching control valve 63 communicates with each other, and the pressure oil from the first pump does not join, so that the crusher crushes. There was a problem that the operation of the machine became unstable. The present invention has been made against the background as described above, and an object thereof is to provide a hydraulic circuit for a construction machine in which the operation of a crusher or the like operates stably.

[0020]

In order to solve the above-mentioned problems, the apparatus according to the first aspect is such that the arm second switching valve and the second preliminary switching control valve are connected in parallel to the center oil passage of the first hydraulic pump. Then, the first call switching control valve and the arm first switching control valve for controlling the hydraulic cylinder of the working machine such as the crusher or the breaker are connected in series to the center oil passage of the second hydraulic pump, and the first hydraulic pump of the first hydraulic pump is connected. A branch oil passage branched from the upstream of the center oil passage is merged with an input oil passage of the first call switching control valve via a logic valve, and a crusher is connected to the first call switching control valve to connect the second call switching. Connect the second preliminary work machine to the control valve
The secondary pressure oil passage of the remote control valve is connected to the input port of the first shuttle valve, is connected to one of the output ports of the second shuttle valve, and the other input port of the second shuttle valve is output of the solenoid valve. The solenoid valve when the secondary pressure detecting device detects the secondary pressure of the second auxiliary remote control valve by connecting the output port of the second shuttle valve to the pilot port of the arm second switching valve. Output port is connected to the oil tank, and when the crusher is operated independently, the oil passage between the input and output ports of the arm second switching valve is shut off, and the oil passage between the input and output of the logic valve is connected. The pressure oil of the first hydraulic pump is merged with the pressure oil of the second hydraulic pump, and the second preliminary work machine is operated independently or first.
A hydraulic circuit for a construction machine capable of using a crusher or the like, which is provided with a control circuit for supplying the pressure oil of the first hydraulic pump to the second preliminary switching control valve when operated in combination with the preliminary work machine. .

According to a second aspect of the present invention, in the hydraulic circuit, the arm second switching control valve is a switching valve that connects the center oil passage in the neutral state and shuts off the oil passage between the input and output ports in other states. And an oil passage on one side of the arm remote control valve and an oil passage on the control circuit are connected to both input ports of the shuttle valve, and an oil passage on the output side of the shuttle valve is connected to the first pilot port of the arm second switching valve. When the other side output oil passage of the arm remote control valve is connected to the second pilot port of the arm second switching control valve via the opening / closing valve and the crusher or the second work standby machine is operated. The hydraulic circuit of a construction machine according to claim 1, wherein the on-off valve is configured to shut off an oil passage.

[0022]

[0023]

DETAILED DESCRIPTION OF THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. <Embodiment 1> FIG. 1 is a diagram showing a circuit configuration of Embodiment 1 of the present invention. In FIG. 1, the same components as those described in the conventional device, particularly the conventional device 2, are denoted by the same reference numerals and detailed description thereof will be omitted. In FIG. 1, the oil passage 85 from the open side output pilot port of the arm remote control valve 65 is connected to the open side pilot port 63b of the arm first switching control valve 63 via the opening / closing valve 86. The pilot port of the opening / closing valve 86 is connected by providing a branch oil passage 87 from the output oil passage 81 of the electromagnetic switching valve 75, and the opening / closing valve 86 is shut off when pilot pressure oil acts on the pilot port, and communicates when it does not act. Is configured.

The first embodiment has the above configuration and functions as follows. That is, the on-off valve 86 is in a communication state when the crusher is not used. Therefore, if the arm remote control valve 65 is operated, the arm first switching control valve 54 and the arm second switching control valve 63 operate in the same manner as in the conventional device 2,
Increase the operating speed of the arm cylinder. Further, when the crusher is in use, that is, the crusher selection switch 77 is turned on and the auxiliary remote control valve 70 is operated, the pilot hydraulic pressure is changed to the oil passage 71.
Alternatively, when it appears at 72, the open / close valve 86 is in the shut-off state. Therefore, at this time, the arm second switching control valve 63 is in the state A, and the pressure oil from the first hydraulic pump is in the center oil passage 6
It flows through the oil passage 67 branched from 2, and joins the input port of the first preliminary switching valve 53 via the logic valve 68.

According to the configuration of the first embodiment, the pressure oil of the first hydraulic pump 61 is always kept in the first preliminary switching valve 53 while the crusher is in use.
Since it merges with the input port of, the effect that a stable crusher can be operated can be obtained.

FIG. 2 is a diagram showing a circuit configuration according to the second embodiment of the present invention. In FIG. 2, the same components as those described in the conventional device 2 or the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted. In FIG. 2, the second preliminary switching control valve 9
1 is connected to the center oil passage 62 of the first hydraulic pump 61 in parallel with the arm second switching control valve 63. Output oil passages 93 and 94 of the second auxiliary remote control valve 92 are connected to the pilot port of the second auxiliary switching control valve 91, and a shuttle valve 95 is connected between these oil passages 93 and 94. The output oil passage 96 of the shuttle valve 95 is connected to the second pressure switch 97. The second pressure switch 97 is a normally closed switch that is turned off (opened) when a pilot pressure acts, and includes a pressure switch 74, a solenoid of an electromagnetic switching valve 75,
Connected in series with the power supply 76 and the crusher selection switch 77,
An electrically closed circuit 78 is formed.

A branch oil passage 98 from the output oil passage 96 of the shuttle valve 95 is connected to one input side of a shuttle valve 99 provided on the oil passage 79, and the output oil passage 8 of the shuttle valve 99 is connected.
2 is connected to the input port of the shuttle valve 80. The oil passage 100 branched from the oil passage 82 is connected to the pilot port of the opening / closing valve 86. The solenoid switching valve 7
The oil passage 87 connecting the output oil passage 79 of No. 5 and the pilot port of the on-off valve 86 is cut off on the way.

The second embodiment having the above configuration functions as follows. When the crusher is operated independently, that is, when the second auxiliary remote control valve 92 is not operated at the same time, the pilot pressure oil does not appear in the output oil passages 93 and 94 of the second auxiliary switching control valve 91, and the second pressure switch 97 is used. Remains closed. Therefore, turn on the crusher selection switch 77,
When the auxiliary remote control valve 70 is operated, the pressure switch 74 is turned on, a solenoid current flows through the electric circuit 78, and the solenoid valve 78 is brought into a communication state.

The pilot hydraulic pressure from the shuttle valve 73 flows into the oil passage 81 and the oil passage 79 via the solenoid valve 75. The pressure oil that has flowed into the oil passage 79 passes through the shuttle valves 99 and 80, and the closing side pilot port 63a of the arm second switching control valve 63.
And the arm second switching control valve 63 is brought into the state i, that is, the cutoff state. Further, the pilot pressure oil from the shuttle valve 99 flows through the oil passage 82 and the oil passage 100 to the pilot port of the opening / closing valve 86, and the opening / closing valve 86 is closed. As a result, the oil passage between the output oil passage 85 of the arm remote control valve 65 and the pilot port 63b of the second arm switching control valve 63 is shut off.

On the other hand, the pilot pressure oil flowing in the oil passage 81 flows to the pilot port of the control valve 69 to bring the control valve 69 into communication with the logic valve 68. Therefore, the pressure oil from the first hydraulic pump 61 is supplied to the oil passage 67.
Through the logic valve 68 and the second hydraulic pump 51
And join the center oil passage 52. At this time, even if the arm remote control valve 65 is operated at the same time, the arm second switching control valve 63
Is in the state a, and the merging from the first hydraulic pump 61 is performed, so that stable crusher operation is possible.

Next, the case where the second auxiliary remote control valve is independently operated will be described. Since the pressure switch 74 and the crusher selection switch 77 are turned off, the solenoid valve 75 is in the shut-off state. Therefore, the pilot pressure oil does not appear in the oil passage 81, and the control valve 69 and the logic valve 68 are shut off.
The pressure oil from the first hydraulic pump 62 is supplied to the first preliminary switching control valve 5
Do not join the 3 input port. However, since pilot pressure oil flows into one of the output oil passages 93 and 94 of the second auxiliary remote control valve 92, the pressure oil flows to the oil passage 82 and the branch oil passage 100 via the shuttle valve 95 and the shuttle valve 99. It flows into the pilot port of the on-off valve 86, and shuts off the on-off valve 86.

The pressure oil flowing in the oil passage 82 switches the arm second switching control valve 63 to the state A via the shuttle valve 80. Therefore, the pressure oil of the first hydraulic pump 61 flows to the second preliminary switching control valve 91, and the second preliminary machine can be used independently. In this case, even if the arm is operated, the arm second switching control valve 63 maintains the state A, and the stable operation of the second standby machine becomes possible.

Finally, the case where the crusher and the second spare machine are used at the same time will be described. Second spare remote control valve 92
When is operated, the pilot pressure oil flows into the oil passage 96 via the shuttle valve 95, and the second pressure switch 97 is turned off (open). This results in the logic valve 68 as described above.
Is cut off. Further, the pilot pressure oil does not flow in the oil passage 79, but the pilot pressure oil flows in the oil passage 98, so that the pilot pressure oil flows to the pilot port 63a of the arm second switching control valve 63 via the shuttle valve 99 and the shuttle valve 80. And the arm second switching control valve 63 is switched to the state a.

Further, the pilot pressure oil flowing into the oil passage 82 flows through the oil passage 100 to the pilot port of the on-off valve 86, and shuts off the on-off valve 86. Therefore, the output oil passage 85 of the arm remote control valve 65 and the arm second switching control valve 6
When the arm remote control valve 65 is operated, the state of the arm second switching control valve A does not change. Stable operation of the crusher and the second spare machine becomes possible.

As described above, in the second embodiment, the crusher and the second spare machine can be used simultaneously and independently, and when the crusher is used alone, the hydraulic oils of the first and second hydraulic pumps are combined. It enables high speed work. Further, in any of the above-mentioned uses, even if the arm remote control valve is operated, the pressure oil flow rate does not change, so stable operation is possible.

The embodiments and examples of the present invention have been described in detail above with reference to the drawings. However, the specific configuration is not limited to these examples, and design changes within the scope not departing from the gist of the present invention. Etc. are included in the present invention.

[0037]

As described above, according to the configuration of the present invention, the amount of hydraulic oil supplied from the hydraulic pump does not change even if the arm is operated while the spare machine such as the crusher is in use. This has the effect of enabling stable operation of the crusher and the like.

[Brief description of drawings]

FIG. 1 shows a circuit configuration of a first embodiment of the present invention.

FIG. 2 shows a circuit configuration of a second embodiment of the present invention.

FIG. 3 shows a conventional circuit.

FIG. 4 shows a crusher.

FIG. 5 shows a breaker.

FIG. 6 shows another conventional circuit.

[Explanation of symbols]

51 second hydraulic pump 52, 62 center oil passage 53 preliminary switching control valve (first preliminary switching control valve) 54 arm first switching control valve 61 first hydraulic pump 63 arm second switching control valve 65 arm remote control valve 68 logic valve 69 control valve 70 spare remote control valve 77 crusher selection switch 80 shuttle valve 91 second preliminary switching control valves 95, 99 shuttle valve (first and second shuttle valves)

Claims (2)

(57) [Claims] 1. An arm second switching valve and a second preliminary switching control valve are connected in parallel to a center oil passage of a first hydraulic pump, and a work machine such as a crusher or a breaker is connected to a center oil passage of the second hydraulic pump. A first spare switching control valve for controlling a hydraulic cylinder and an arm first switching control valve are connected in series, and a first spare is provided via a logic valve to a branch oil passage branched from an upstream of a center oil passage of the first hydraulic pump. The input oil passage of the switching control valve is joined, the crusher is connected to the first preliminary switching control valve, the second preliminary working machine is connected to the second preliminary switching control valve, and the secondary pressure of the second remote control valve is connected. Connecting the oil passage to the input port of the first shuttle valve, connecting to one of the output ports of the second shuttle valve, connecting the other input port of the second shuttle valve to the output port of the solenoid valve, Connect the output port of the second shuttle valve to the pilot port of the arm second switching valve. When the secondary pressure detecting device detects the secondary pressure of the second auxiliary remote control valve, the output port of the solenoid valve communicates with the oil tank, and when the crusher is operated independently, the arm first The oil passage between the input / output ports of the two switching valves is shut off, and the oil passage between the input and output of the logic valve is made to communicate with each other so that the pressure oil of the first hydraulic pump merges with the pressure oil of the second hydraulic pump. A crusher or the like characterized by having a control circuit for supplying the pressure oil of the first hydraulic pump to the second preliminary switching control valve when the preliminary working machine is operated alone or in combination with the first preliminary working machine. Hydraulic circuit of usable construction machinery. 2. The arm second unit in the hydraulic circuit.
The switching control valve connects the center oil passage in the neutral state,
In other states, it is configured by a switching valve that shuts off the oil passage between the input and output ports, and the one-side output oil passage of the arm remote control valve and the output oil passage of the control circuit are connected to both input ports of the shuttle valve, and the shuttle valve is connected. Output side oil passage is connected to the first pilot port of the arm second switching valve, and the other side output oil passage of the arm remote control valve is connected to the second pilot port of the arm second switching control valve via an opening / closing valve. The construction machine capable of using the crusher according to claim 1, wherein the on-off valve is configured to shut off the oil passage when the crusher or the second work standby machine is operated. Hydraulic circuit.