JP2003148414A - Oil pressure circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain an oil pressure circuit used in a construction machine having a safety device and an automatic idling function from getting fat. SOLUTION: This oil pressure circuit is used in the construction machine having the safety device for informing the running operation to the people around it, and an automatic idling function for controlling the rotating speed of a driving source according to the operating condition of each actuator. The circuit is provided with direction switching valves 16, 17 for running for controlling the connecting direction of a hydraulic pump, or a tank and a running device and the flow, the other direction switching valves 11, 12, 13, 14, 15, 18, 19 for controlling the connecting direction of the pump or the tank and an actuator other than the above running device, an oil passage 99 for a running signal for generating a running signal in response to the operation of the direction switching valve for running, and an automatic idling oil passage 97 for generating an automatic idling signal in response to the operation of the other direction switching valves. According to the oil passage 99 for a running signal and the automatic idling oil passage 97, the rotating speed of the driving source is controlled.

Description

Description: BACKGROUND OF THE INVENTION [0001] The present invention relates to a plurality of actuators.
For hydraulic circuits that supply pressurized oil to
Crawler vehicle equipped with multiple actuators such as shovels
The present invention relates to a hydraulic circuit used for a construction machine such as a vehicle. [0002] A traveling device and a plurality of actuators are provided.
Construction machines such as crawler vehicles
An automatic controller that controls the rotation speed of the drive source according to the operating state
It has an idle function. [0003] Therefore, each of the above-mentioned auto idle functions is used.
Auto idle signal to detect actuator operation status
A circuit for extracting the signal is provided. On the other hand, this construction machine is running.
Lights or siles to inform people around you
A safety device such as a safety device may be provided. [0005] In this case, too, the construction machine described above is used.
In order to operate the safety device in the hydraulic circuit,
A circuit is provided to extract the running signal to detect the operation state of the vehicle.
It is. SUMMARY OF THE INVENTION [0006]
As a road, a pilot is separately provided for the direction switching valve for the traveling device.
It is conceivable to provide a valve.
The switching valve will be enlarged. The present invention provides a safety device and an auto idle function.
The hydraulic circuit used in the construction machine with
The purpose is to suppress enlargement. Means for Solving the Problems Claims for solving the above problems
The hydraulic circuit described in item 1 notifies the surroundings that the vehicle is running.
Depending on the operating condition of each actuator
Auto idle function to control the rotation speed of the drive source
Used for construction machinery equipped with a hydraulic pump or tank
Traveling device that controls the connection direction and flow rate with the traveling device
Directional control valve, the pump or tank and the traveling device
Control the connection direction and flow rate with other actuators outside
The other directional control valves to be controlled and the directional control valve for traveling are operated.
A travel signal oil passage that emits a travel signal by being
Auto idle signal when other directional control valve is operated
An oil passage for an auto-idle that emits
Drive on the basis of the oil passage for
It is characterized in that the rotation speed of the source is controlled. According to this configuration, the automatic idle function
The signal generation oil passage for the traveling directional control valve and the other
Separated for the direction switching valve, and the oil passage for the traveling signal is used for the safety device.
Because it can be used for auto idle, safety equipment
Need to provide pilot passages and sub-valves
Directional valve can be prevented from becoming too large
You. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an oil according to an embodiment of the present invention.
The voltage circuit will be described with reference to the drawings. Figure 1
This embodiment, FIG. 3 shows a modified example, and FIG. 5 shows a hydraulic circuit of the present invention.
1 illustrates a construction machine in which is used. (Embodiment) A hydraulic circuit 1 according to this embodiment
Is, for example, a plurality of hydraulic actuators as shown in FIG.
Used for construction equipment such as mini excavators 150 equipped with
As shown in FIG. 1, each hydraulic actuator and each pump
Or control the connection direction with the tank and the flow rate of pressurized oil
It is provided with a plurality of directional control valves (11 to 19) and the like.
You. In FIGS. 1 and 5, directional control valves 11 to 11 are shown.
19, each actuator of the mini excavator 150 shown in FIG.
Actuator port A1 connected to each eta
~ 7, A9 ~ 10, B1 ~ 8, B10
You. Some of the actuators corresponding to each directional control valve are
As shown in FIG. 1 and referring to FIG.
11 is connected to a boom swing actuator (not shown).
Directional switching valve 12 is a dozer
For the cylinder 24 connected to 23, the directional control valve 13 turns
Hydraulic motor that drives the table 33 (slewing actuator)
(Not shown), the directional control valve 14 is reserved (service)
The directional control valve 15 is
The direction switching valve 16 for the arm cylinder 26 is a left-side traveling device.
Directional switching valve for hydraulic motor (not shown) for driving 27
17 is a hydraulic motor (not shown) for driving the right traveling device 28.
Directional valve 18 is a boom cylinder of boom 29
30, the directional control valve 19 is a bucket serial of the bucket 31.
For the solder 32. These directional control valves 11 to 19 are operated.
The return and return of pressure oil to each actuator
The connection direction is switched, and each actuator is actuated.
Will be. The direction switching valves 11, 12, 14, 1
Reference numerals 6 and 17 denote manually operated directional switching valves, which are directional switching valves.
13, 15, 18, and 19 are remote-controlled directional control valves.
It is. In FIG. 1, a hydraulic circuit 1 is not shown.
Pressure oil is supplied from three pumps (first to third pumps)
The first pump 3 is connected to the pump port P1
The second pump 4 is connected to the pump port P2 and the third pump 5
Are connected to the hydraulic circuit 1 at pump ports P3, respectively.
You. The hydraulic circuit 1 is supplied with pressure oil.
Depending on the connection configuration with each pump, three circuits (first circuit)
a, a second circuit b, and a third circuit c). First,
One circuit a is provided from the first pump 3 through the pump port P1.
Is supplied to the first unload passage 34
Direction switching valves 17, 18 and 19. 1st Ann
At the most upstream side of the load passage 34, a right-traveling directional control valve 1
7 is disposed on the downstream side, and a right-direction switching valve 17
Other directional control valves (18, 19) other than
You. Each of these directional control valves 17, 18, 19 is provided with a first
Passages 45, 46, 47 from the
Even if it is connected, it will be supplied with pressurized oil. Soshi
Through the discharge passages 48, 49, 50, respectively.
It communicates with the passage 35. Also, the first unload passage 3
4 also communicates with the tank passage 35. In addition,
The tank passage 35 is connected via tank ports T1 and T2.
To the tank 36. Next, the second circuit b is supplied from the second pump 4
Pressure oil is supplied through the pump port P2, and the
Direction switching valves 14, 15, 16
It has. On the most upstream side of the second unload passage 38
Is equipped with a directional control valve 16 for left traveling,
Other direction switching valves (15, 1) other than the left traveling direction switching valve
4) is arranged. And directional switching valves other than spare
15 and 16, the second unload passage 38 to the passage 51,
52, while receiving the supply of pressure oil,
Through the discharge passages 53 and 54 to the tank passage 35, respectively.
Communicating. Further, the lowermost stream of the second unload passage 38
Side is the tank passage 35 as in the first unload passage 34.
Leads to. The first pump 3 and the second pump 4
And a supply switching valve between the first circuit a and the second circuit b.
The supply switching valve 21 is connected to the tank passage.
Unlow communicating with passage 35 through passages 70 and 71
By switching from the operating position 21a to the operating position 21b,
From the first pump 3 and the second pump 4 to the first circuit a and the second
Pressure oil can be supplied to the circuit b. Unload position
Switching from the operation position 21a to the operation position 21b is performed by the pilot.
The pilot pressure oil from the pump 7 is
p2 and the supply switching valve 21 via the pilot oil passage 39.
This is performed by acting on the pilot pressure receiving portion 40. Chi
Incidentally, this pilot pressure signal will be described later. Finally, the third circuit c is supplied from the third pump 5
Pressure oil is supplied through the pump port P3, and the supply passage 4
1 is connected in the third unloading passage 42 via
Valves 11, 12, and 13 are provided. 3rd unload passage
42 in the order of directional control valves 11, 12, and 13 from the upstream side.
Downstream of the turning direction switching valve 13 on the most downstream side.
Are connected to a merge valve 20 described later. And supply
From the passage 41 to the direction switching valves 12 and 13,
55, 56 are connected, and further, the directional control valve 11,
12 and 13 pass through discharge passages 57, 58 and 59, respectively.
And is in communication with the tank passage 35. In the third circuit c, the third unlock
From the supply passage 41 leading to the upstream side of the feed passage 42.
The passage 60 leading to the tank passage 35 through the roof valve 43 is
It has branched. Then, from the middle of this passage 60,
The supply passage 61 leading to the flow valve 20 branches. In addition,
The supply passage 61 is further branched into two,
20. The merging valve 20 passes through the supply passage 61 described above.
To communicate with the third pump 5 and through the discharge passage 62.
And is in communication with the tank passage 35. Also, the merging valve 20
First through the check valves 63 and 64 respectively
The passage 65 and the second merging passage 66 are connected. 1st merge
The passage 65 communicates with the first circuit a, and the second joining passage 66
Communicates with the second circuit b. The first merging passage 65 is provided in the first circuit a.
Other directional switching valves 18, 1 other than the right traveling directional switching valve 17,
9 through the passages 46 and 67, respectively.
In the passage 67, a throttle 68 is provided on the way, and
Boom directional control valve 18 rather than directional control directional control valve 19
Pressure oil can be supplied preferentially. The second merging passage 66 is connected to the second circuit b.
Directional switching valve 1 other than left traveling directional switching valve 16
4 and 15 through passages 51 and 69, respectively.
I have. The passage 51 also merges with the second unload passage 38
ing. Next, the merging valve 20 allows the third pump
5 and the first merging passage 65 and the second merging passage 66
A switching configuration for passing or blocking will be described. The merging valve 20 is located at the unload position 20a,
1st switching position 20b, 2nd switching position 20c, running position 20
d with four switching positions, and
Lot pressure command is sent to pilot pressure receiving units 72, 73, 74.
In operation, the merging valves are respectively brought into the first switching position 20.
b, switch to second switching position 20c, running position 20d
It is something that can be done. The first switching position 20b and the second disconnection
Between the switching position 20c and the pilot pressure receiving portion 73.
Is switched proportionally / stepwise in accordance with. Hereinafter, FIG.
FIG. 2 is an enlarged circuit diagram of the merge valve 20.
The switching positions will be described in order. First, the unload position 20a is
The pilot pressure is controlled by a valve (not shown)
Is not supplied, is held by the spring 75
Position. The unload position 20a is
When one 61a of the path 61 communicates with the tank path 35,
The other supply passage 61b is shut off, and the turning direction switching valve is turned off.
13, the third unloading passage 42 on the downstream side
It communicates with 66. Note that the second merging passage 66 is
It communicates with the unload passage 38. Next, the first switching position 20b is
The pilot pressure is supplied to the
Can be replaced. The pilot pressure oil is supplied to the pilot port Pp
Pilot pressure receiving section from 1 through pilot oil passage 76
Acts on 72. The pilot oil passage 76
Oil passages 79 and 80 communicate with each other.
The pilot pressure is
The pressure of the pressure receiving section 72 does not decrease and the unloading position
The position is switched from 20a to the first switching position 20b. Note that the pilot oil passage 79 is
Pilot pressure oil is applied to the pressure receiving pressure part 74 to run position 2
For switching to 0d
It will be described later. Further, the oil passage 80 is connected to the directional control valves 13 and 1.
5 sub-valves 13s and 15s.
Communication and shut off by these sub-valves
The most downstream side of the oil passage 80 is connected to the tank passage 35.
Through. And, the number of the directional control valves 13 or 15 is small.
By switching one of them, the oil passage 80 is shut off,
Pressure oil is supplied to an oil passage 81 branched from a passage 80,
The turning negative shown (pressure for brake release) is taken out
(See FIG. 1). The first switching position 20b is moved from the third pump 5
Two supply passages 61a to which pressure oil is directly supplied;
61b, shut off the third unload passage 42.
The flow side communicates with the second merging passage 66. That is, the third point
Supply from the pump 5 to the directional control valves 11 to 13 of the third circuit c
The surplus pressure oil of the pressure oil that has passed through the second joining passage 66
To be supplied to the directional control valves 14 and 15 of the two circuits b
become. Next, the second switching position 20c will be described.
I do. The second switching position 20c is located at one side 61 of the supply passage 61.
a through a communication path 84 provided with a throttle 83.
It communicates with the flow passage 65, and further branches off from the communication passage 84 to restrict it.
To the second junction passage 66 via a communication passage 87 provided with
Also communicate. The other supply passage 61b is shut off.
I will leave it. And, downstream of the third unload passage 42
Side communicates with communication passages 84 and 87 via communication passage 86
Without passing through the first junction passage 65 through the throttle,
The passage 66 is communicated via a throttle 85. The merging valve 20 is connected between the first switching position 20b and the second switching position 20b.
Between the switching position 20c and the pilot port Pa8 '
It moves proportionally / stepwise depending on the pressure. pilot
The port Pa8 'is used for raising the boom of the boom cylinder 30.
Pilot port Pa8 of the directional control valve 18 for commanding operation
The pilot pressure sent to This allows direction switching
When the valve 18 is not operated, the merging valve 20
Pressure oil that is located at the switching position 20b and is pressure-fed to the third circuit c
To the first circuit a in which the directional control valve is not operated
Waste to the second circuit b that requires the supply of pressure oil
And the directional control valve 18 was operated.
In this case, the pressure oil of the third pump 5 is supplied to the second circuit b and the first circuit a.
Can be supplied. Further, the merging valve 20 is connected to the first switching position 20.
b between the second switching position 20c and the pilot port P
a8 'to move proportionally / stepwise according to the pressure
Then, for example, increase the raising speed of the boom cylinder 30
Pilot pressure from a remote control valve (not shown)
When it is raised, the directional control valve 18 moves to the position 18a side.
At the same time, the junction valve 20 is also moved to the second switching position 20c.
Move. Therefore, the pressure oil sent to the second circuit b is reduced,
Pressure oil to the first circuit a. Thus the boom cylinder
30 depending on the amount of oil required by the first and second circuits a,
The combined oil amount can be distributed to b. The running position 20d of the merge valve 20 is
Upstream of the directional control valves (11, 12, 13) of the three circuits c
The first circuit a and the second circuit via the diaphragms (83, 85)
b and the directional control valve (1
1, 12, 13) from the downstream side as well as the first circuit a and the second
Because it is connected to the path b, the pressure from the third pump 5 to the third circuit c
While supplying oil, pressurized oil pumped from the third pump 5
Can be supplied to the first circuit a and the second circuit b,
In addition, the directional control valves (11, 12, 13) of the third circuit c
Excess pressure oil discharged from the downstream side is also supplied to the first circuit a and the second
It can be pumped to path b. Therefore, the third pump 5
Pressure oil is effectively applied to the first circuit a and the second circuit b.
Can be distributed efficiently, and each actuator (2
5, 29, 31) can also be improved. The pilot port Pa8
The first switching position 20b of the merging valve 20 and the second
The switching amount between the switching position 20c and the switching position is determined.
Pilot port Pa5 of the directional control valve 15
Pressure, boom direction switching valve 18 and bucket direction switching
At least one or both operations of the valve 19 and the like are performed.
The condition may be used. Furthermore, the boom
The load pressure of the cylinder 30 and the arm cylinder 26,
The switching amount of the merge valve 20 may be determined by comparing the pressures.
No. Finally, the running position 20d will be described.
You. The running position 20d is connected to one of the
The supply passage 61 a is connected to the first junction passage 6 through the first throttle 91.
5 and the other supply passage 61b is connected to the second throttle 94.
It is connected to the second merging passage 66 via the passage 93. Further
Then, the downstream side of the third junction passage 42 is communicated with the communication passage 92.
The first joining passage 65 is connected through the communication passage 95. Switching to the running position 20d is performed by pilot
The pilot pressure is supplied to the
Done. That is, the pilot pump 6
The pressure oil sent through the oil passage 76 passes through the throttle 77
Some are also sent to the pilot oil passage 79. Pilot oilway
79 is connected to the pilot pressure receiving portion 74,
The branch branches to an oil passage 88. The oil passage 88 is provided with the directional control valve 16,
Sub-valve 1 provided in each of 17, 18 and 19
6s, 17s, 18s, 19s and connected in this order
And the most downstream side thereof communicates with the tank passage 35.
You. The sub valves 18s and 19s are
By operating the switching valves 18 and 19 respectively, the oil passage 8
8 is changed from the communication state to the cutoff state. And the sub-valve
In 16s and 17s, the directional control valve 16 and
17 is operated, the oil passage 88 remains in the communication state.
The oil passage 89 or 90 is shut off. These oil passages (79, 88, 89, 90)
, The right-direction switching valve 17 and the left-travel
Direction switching valve 16 and the right traveling type in the first circuit a.
The number of directional switching valves 18 and 19 other than the directional switching valve 17 is small.
When both are operated, the pilot pump 6
The pilot pressure oil sent from the
Acting, the merging valve 20 is switched to the running position 20d.
You. With the configuration of the running position 20d,
Other than directional control valves (16, 17) and traveling directional control valves
The directional control valves (18, 19) are operated simultaneously
Ensures that the third pump is switched to the other directional control valve (18, 19).
Pressure oil fed from the pump 5 can be supplied. Further
The traveling position 20d of the merger valve 20 is in the direction of the third circuit c.
From the upstream side of the switching valves (11, 12, 13) via the throttle 91
To the first circuit a, and the directional control valve (1
1, 12 and 13) from the downstream side through the passage 95 as well.
Because it is connected to the circuit a, the third pump c
While supplying the pressure oil, the pressure oil of the third pump 5 is supplied to the first circuit a.
And the direction switching of the third circuit c.
Excess pressure discharged from the downstream side of the valves (11, 12, 13)
Oil can also be pumped to the first circuit a. Therefore,
3 Efficiently and efficiently using pressure oil from the pump 5 to the circuit a
The actuators (25, 2, 2) of the third circuit c can be distributed.
The operability of (9, 31) can also be improved. Here, the traveling provided in the hydraulic circuit 1
Explanation of the signal and auto idle signal extraction configuration
I do. Equipped with a traveling device and a plurality of actuators
For construction equipment such as crawler vehicles,
Auto-eye that controls the rotation speed of the drive source according to the operating condition
A dollar function is provided. Therefore, each of the above-mentioned auto idle functions
Auto idle signal to detect actuator operation status
A circuit for extracting the signal is provided. On the other hand, this construction machine is running.
Lights or siles to inform people around you
A safety device such as a safety device may be provided. Also in this case, the above-mentioned construction machine is used.
In order to operate the safety device in the hydraulic circuit,
A circuit is provided to extract the running signal to detect the operation state of the vehicle.
It is. As a circuit for extracting a traveling signal, a traveling device
Consider installing a separate pilot valve in the directional control valve
However, the directional control valve for traveling is enlarged by that much.
Will be lost. The hydraulic circuit 1 according to this embodiment will be described later.
Construction machine with safety device and auto idle function
Hydraulic circuits used in machines
Is also suppressed. That is, the hydraulic circuit 1
Safety device that informs the surroundings and the operation of each actuator
Auto-eye that controls the rotation speed of the drive source according to the operating condition
Used for construction machinery with a dollar function,
Or connection direction and flow rate between tank and traveling device
Traveling directional control valve and the pump or tank
Connection direction with other actuators other than
And a directional control valve for controlling the flow direction and the traveling direction.
For running signals that generate a running signal when the switching valve is operated
The automatic operation is performed by operating the oil passage and the other directional control valve.
And an auto-idle oil passage that issues an idle signal.
The travel signal oil passage and the auto idle oil passage
Hydraulic circuit that controls the rotation speed of the drive source based on the
You. Referring to FIG.
Pilot pressure supplied through pilot port Pp2
Oil is supplied by pilot operation via pilot oil passage 39
Acts on the pilot pressure receiving portion 40 of the switching valve 21
The oil is also supplied to the automatic idle passage 97 through the throttle 96.
Paid. In addition, a throttle 98 is provided in the pilot oil passage 39.
And a travel signal oil passage 99 communicates therewith. The travel signal oil passage 99 is connected to the switching valve communication oil passage 9.
9a and a traveling signal branched from the switching valve communication oil passage 99a.
And a take-out oil passage 99b. Switching valve communication oil passage 99
a is each sub-valve of the traveling direction switching valve (16, 17).
(16s, 17s) and then connected to oil passage 90
By doing so, it communicates with the tank passage 35. And run
The line signal oil passage 99b communicates with the traveling signal output port PL.
are doing. As described above, the pilot pump 7 and each oil passage
(35, 39, 40, 90, 98, 99) are connected
The construction machine equipped with the hydraulic circuit 1 (mini
The excavator 150) informs the surroundings that the vehicle is running.
The driving signal to light the safety device for
be able to. That is, it flows into the traveling signal oil passage 99.
The pilot pressure oil is supplied to the traveling directional control valve (16, 1, 1).
7) is not operated, the switching valve communication oil passage 99a and
And flows through the oil passage 90 to the tank passage 35. this
From the state, at least the traveling direction switching valves (16, 17)
When one of them is operated, the mini excavator 150
At the same time, the switching valve communication oil passage 99a is shut off.
As a result, pressure is generated in the traveling signal extraction oil passage 99b,
A running signal is generated at the take-out port PL. This running signal
Pressure switch, etc. for operating a safety device not shown
, The mini excavator 150 travels
Activate a safety device to notify the surroundings that
Let The automatic idle oil passage 97 is switched
The valve communication oil passage 97a is separated from the switching valve communication oil passage 97a.
It has a divergent auto idle signal extraction oil passage 97b.
You. The switching valve communication oil passage 97a is connected to the traveling direction switching valve (1).
6, 17) other directional switching valves (19, 18, 15,
14, 13, 12, 11) (19s, 1
8s, 15s, 14s, 13s, 12s, 11s)
, And communicate with the tank passage 35. Soshi
The automatic idle signal extraction oil passage 97b is
It communicates with the dollar signal extraction port Ai. The directional control valves (11, 12, 13, 14, 1)
5, 18 and 19) are not operated
Is partially automatic from the pilot pump 7 via the throttle.
The pressure oil that has flowed into the idle oil passage 97 is connected to the switching valve communication oil passage.
It flows to the tank passage 35 through 97a. In this state
The other directional control valves (11, 12, 13, 14, 15,
When at least one of 18, 18) is operated, the switching valve
The communication oil passage 97a is shut off and the automatic idle signal is taken out.
Pressure is generated in the oil passage 97b, and the auto idle signal extraction port
An automatic idle signal is generated at the port Ai. The running signal and the audio signal thus extracted are
Auto-idle, running signal and auto idle
Drive signal is not generated,
Reduce the running speed to a specified value,
When one of the idle signals is generated, the rotation speed of the drive source is
Control is performed to increase the degree to a predetermined value. As described above, for the auto idle function
Of the signal generating oil passage for traveling direction switching valves (16, 17)
And other directional control valves (11, 12, 13, 14, 15,
18, 19) and the travel signal oil passage 99
Because it was used for safety equipment and for auto idle,
Provide pilot passages and sub-valves only for all devices
It is not necessary, and the directional valves 16 and 17 are enlarged.
Can be prevented. (Modification) Next, the oil to which the present invention is applied
Hydraulic circuit 2 according to a modified example of the structure of the pressure circuit
explain. The hydraulic circuit 2 has substantially the same circuit configuration as the hydraulic circuit 1.
In FIG. 2, the corresponding elements
The same reference numerals as those in FIG. Hydraulic circuit 2 and hydraulic circuit 1
Is different in the following three points. First the first
The difference is that the position of the merging valve 20 is
Position 20a, the first switching position 20b, and the second switching position 20c.
The only difference is that there are only three positions. This hydraulic circuit 2
In the junction valve 20 of FIG.
Also serves as a position. The second difference is that the pilot
The difference lies in the configuration of the oil passage communicating with the pumps 6 and 7. No.
3 is that the arm is cut in the direction from the second merging passage 66.
The para-passage 51 connected to the switching valve 15 is connected to the second unload passage.
Connected to the directional control valve 15 without communicating with the path 38
It is. Hereinafter, the first and second differences will be described.
Will be described in detail. First, the first difference will be described with reference to FIG.
Next, the merging valve 20 in the hydraulic circuit 2 shown in FIG.
Will be described with reference to an enlarged circuit diagram of FIG. The junction valve 20
As in the case of the hydraulic circuit 1, the third pump and the first merging passage
65 and the second merging passage 66.
As described above, the unload position 20a and the first switching position
Position 20b and the second switching position 20c.
The pilot pressure command is
Acts on pressure receiving parts (100, 101, 102, 103)
As a result, the merging valves 20 are respectively set to the first switching position 20.
b, second switching position 20c, second switching position (running position) 2
0c, it is switched to the first switching position 20b. In addition,
Between the first switching position 20b and the second switching position 20c,
Proportional to the pressure of the pilot pressure receiving parts 101 and 103
/ It switches in steps. First, the unload position 20a is set at the hydraulic circuit
The same as in the case of 1. Next, the first switching position 20b is set to the third position.
Supply passages 61 to which pressure oil is supplied directly from the pump 5
a and 61b, and beneath the third unload passage 42.
The flow side communicates with the second junction passage 66 via the communication passage 111
I do. In addition, the communication passage 111 is provided with a throttle 112, 1
The communication paths 114 and 115 are also branched via the
Passages 114 and 115 are respectively joined to merge passage 65 and
And a discharge passage 62. The junction valve 20 is
When the pilot pressure oil acts on the pressure receiving section 100,
The position is switched to the switching position 20b. Pilot port Pp1
Oil that communicates with the pilot pressure receiving unit 100
Oil passages 104 and 80 communicate with the passage 76,
Since they are communicated via the apertures 105 and 78, respectively,
The pressure of the pilot pressure receiving unit 100 does not decrease,
Cut from unload position 20a to first switching position 20b
Be replaced. With the above connection configuration, the first switching position 20
In b, the third pump is larger in the second circuit b than in the first circuit a.
5 can be supplied. Also, unnecessary pressure
Since the oil is discharged to the tank through the throttle 115, the third pump
The pump is not overloaded. Next, the second switching position 20c is set in the supply passage.
A communication path 11 provided with a throttle 116 on one 61a of the
7, the first supply passage 65 and the other supply passage.
61b is kept off. And the third
The downstream side of the download passage 42 is communicated with the communication passage 117
While communicating with the first merging passage 65,
Via communication paths 119, 121 having 118, 120
It also communicates with the second merging passage 66 and the discharge oil passage 62. Squeezing
The aperture 120 has a smaller opening than the aperture 113. The first switching position 20b and the second switching position 20c
Between the pilot ports Pa5 and Pa8
The ratio is switched proportionally / step by step. That is,
When the pressure at the pilot port Pa8 increases, the merging valve 20
2 Move to the switching position 20c and increase the amount of oil sent to the first circuit a.
Easy. Conversely, the pressure at pilot port Pa5 increases
And the merging valve 20 moves to the first switching position 20b,
Increase the amount of oil sent to road a. In addition, it is introduced into the merging valve 20 and
Pressure was set to pilot ports Pa5 and Pa8.
Load pressure of arm cylinder 26 and load pressure of arm cylinder 26
May be. The second switching position 20c also serves as a running position.
It is also a thing. That is, the hydraulic pressure is
1st circuit a and 2nd distribution equivalent to the running position 20d of circuit 1
This was done on road b, and the running position 20d was omitted and simplified.
Things. Switching to the second position 20c is performed in the right traveling direction.
The switching valve 17 and the left direction switching valve 16 are both
Turn off other directions on the road a except for the right running direction switching valve 17
When at least one of the switching valves (18, 19) is operated
The pilot pressure oil sent from the pilot pump 6
Acts on the pilot pressure receiving unit 102.
You. From the pilot pump 6 to the pilot oil passage 7
The pressure oil sent through 6 is partially oiled through the throttle 105
It is also sent to road 104. The oil passage 104 is an oil passage for a traveling signal.
106 and the pyrometer through the aperture 107
To the pilot oil passage 108 connected to the
Communicating. The traveling signal oil passage 106 is in the left-right traveling direction.
Connect the sub-valves 16s, 17s of the switching valves (16, 17)
Subsequently, the switching valve communication oil passage 106 communicating with the tank passage 35 is provided.
a and a traveling signal extraction connected to the traveling signal extraction port PL
It branches to the oil passage 106b. From the pilot oil passage 108,
An oil passage 109 is branched downstream of 107, and this oil passage
109 is a boom directional control valve 18 in the first circuit a.
Sub valve 18s and bucket sub valve
19s, and communicates with the tank passage 35
ing. These oil passages (104, 105, 10
6, 107, 108, 109)
Both of the row direction switching valves (16, 17) are operated.
When there is no oil, the pressure oil flowing into the oil passage 104 is
From the oil passage 106a to the tank passage 35. And
At least one of the left and right direction switching valves is operated
And the switching valve communication oil passage 106a is shut off, and the traveling signal is taken out.
A traveling signal is generated from the oil passage 106b. From this state,
Boom directional control valve 18 or bucket directional control valve 1
9 is operated, the oil passage 109 is shut off.
Pressure oil flows into the pilot oil passage 108,
The pressure oil acts on the pressure receiving pressure section 102, and the running position (second cut
(The switching position) 20c. Thus, the traveling direction switching valve (16, 1
7) and other directional control valves (18,
19) Even if both are operated at the same time,
From the third pump 5 to the directional control valves (18, 19)
Pressure oil can be supplied. In the hydraulic circuit 2, the traveling signal and
Pyro to switch to running position (second switching position) 20c
The structure of the passage is different. Communicate with pilot pump 6
From the oil passage 104, the traveling signal oil passage 106, the pilot oil
Branches to Road 108 for running position (second switching position) 20c
The driving signal is extracted from the signal of
It is. This allows pilot passages and supports for safety devices
There is no need to provide a
Enlargement can be prevented. Further, the traveling signal oil passage 106
Switch to line signal and running position (second switching position) 20C
The signal is also used for the travel direction switching valve.
The valves 16 and 17 can be simplified. According to the first aspect of the present invention, the auto-id
The signal generating oil passage for the directional control valve for traveling
And another directional control valve, and the oil passage for the traveling signal is reduced.
Can be used for all devices and for auto idle
Therefore, use a pilot passage or sub-valve
It is not necessary to provide it, and the directional control valve will be enlarged
Can be prevented.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a circuit diagram of a hydraulic circuit according to the present embodiment. FIG. 2 is an enlarged circuit diagram of a merge valve in the hydraulic circuit according to the embodiment. FIG. 3 is a circuit diagram of a hydraulic circuit according to a modification. FIG. 4 is an enlarged circuit diagram of a merge valve in a hydraulic circuit according to a modification. FIG. 5 is a schematic diagram showing a construction machine to which the hydraulic circuit according to the present invention can be applied. [Description of Signs] 1, 2 Hydraulic circuit 3 First pump 4 Second pump 5 Third pump 6 Pilot pump 11 to 19 Direction switching valve 20 Merging valve 20a Unload position 20b First switching position 20b Second switching position 22 Dozer 25 Arm 27 Left traveling device 28 Right traveling device 29 Boom 31 Bucket 33 Swivel base 36 Tank 65 First merging passage 66 Second merging passages 72, 73, 74 Pilot pressure receiving portion 97 Auto idle oil passage 99 Running signal oil passage 150 Mini excavator a First circuit b Second circuit c Third circuit

   ────────────────────────────────────────────────── ─── Continuation of front page    F term (reference) 2D003 AA01 AB01 AB06 BA05 BA07                       DA01 DA03 DB02                 3H089 AA60 AA72 BB27 CC01 CC08                       CC11 DA02 DA07 DA13 DB12                       DB32 GG02 JJ01

Claims (1)

The present invention is applied to a construction machine having a safety device for notifying the surroundings that the vehicle is running and an auto-idle function for controlling a rotation speed of a drive source according to an operation state of each actuator. A traveling direction switching valve for controlling a connection direction and a flow rate between a hydraulic pump or a tank and a traveling device, and a traveling direction switching valve for controlling a connection direction and a flow rate between the pump or the tank and an actuator other than the traveling device. A direction switching valve, a traveling signal oil passage that issues a traveling signal when the traveling direction switching valve is operated, and an auto idle oil that issues an auto idle signal when the other direction switching valve is operated. A hydraulic circuit for controlling a rotational speed of a drive source based on the travel signal oil path and the auto-idle oil path.