JPH05287775A - Hydraulic circuit of civil engineering and construction machinery - Google Patents

Abstract

PURPOSE:To make it possible to realize both relief of the shock caused in the case of traveling combination drive and prevention of the generation of driving fault of other actuator except a traveling motor in the case of the combination drive. CONSTITUTION:A flow variable control means 100a is provided to a branch passage 102 connecting a hydraulic pressure pump 35 to a left traveling directional selector valve 47. A selector valve 106 driving in accordance with signals of operation detection devices A-E detecting operation of directional selector valves 43-46 and 50-52 is provided. In the case the selector valve 106 is switched, pilot pressure of a pilot hydraulic pressure source 105 is supplied to a driving section of the flow variable control means 100a, during the specific time, a throttle amount of the flow variable control means 100a is so controlled that it is changed over from a small amount of a large one. When it is moved from traveling only to traveling, turning, boo or combination control of arm, at least specific time is so set that pressure oil is supplied to the left traveling directional selector valve 47.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit for a civil engineering / construction machine such as a hydraulic excavator capable of performing a combined operation of simultaneously performing a traveling operation and a revolving structure, a boom, an arm and the like.

[0002]

2. Description of the Related Art FIG. 5 is a circuit diagram showing a hydraulic circuit of a hydraulic excavator cited as an example of a hydraulic circuit of a conventional civil engineering / construction machine of this type. This conventional technique includes a plurality of hydraulic pumps, that is, a first hydraulic pump 35 and a second hydraulic pump 36. These hydraulic pumps 35 and 36 are driven by prime movers 37 and 38, respectively, and their discharge pressures are set by relief valves 62 and 63, respectively.

The discharge line 41 of the first hydraulic pump 35 is
It is connected to the first switching valve group 39. The first switching valve group 39 includes the directional control valve 43 for turning at the upstream position.
And has a directional control valve 4 for the arm sequentially downstream thereof.
4, boom direction switching valve 45, spare direction switching valve 46,
It has one of the left and right, that is, the left traveling direction switching valve 47. The swing direction switching valve 43 is connected to a swing motor 53 that drives a swing body (not shown), the arm direction switching valve 44 is connected to an arm cylinder 54 that drives an arm (not shown), and the boom direction switching valve 45 is not shown. The left traveling direction switching valve 47 is connected to a boom cylinder 55 that drives a boom, and is connected to a left traveling motor 57 that drives a left crawler belt (not shown).

The discharge line 42 of the second hydraulic pump 36 is
It is connected to the second switching valve group 40. The second switching valve group 40 has the other of the left and right, that is, the right traveling direction switching valve 49 at the upstream position, and the second boom direction switching valve 50 and the bucket direction switching are sequentially arranged downstream thereof. It has a valve 51 and a second arm directional control valve 52. The right traveling direction switching valve 49 is connected to a right traveling motor 58 that drives a right crawler belt (not shown), and the second boom direction switching valve 50 is connected to a boom cylinder 55 that drives a boom (not shown), and a bucket direction switching valve is connected. The valve 51 is connected to a bucket cylinder 56 that drives a bucket (not shown), and the second arm direction switching valve 52 is connected to an arm cylinder 54 that drives an arm (not shown).

A counter balance valve 90 is provided between the left traveling direction switching valve 47 and the left traveling motor 57.
A counter balance valve 91 is provided between the right traveling direction switching valve 49 and the right traveling motor 58.

A discharge line 42 of the second hydraulic pump 36,
A first branch passage 59 is connected to the input port of the left traveling directional control valve 47. In the first branch passage 59,
An on-off valve 60 that opens and closes the first branch passage 59, and a check valve 61 that is provided downstream of the on-off valve 60 and that prevents a reverse flow toward the discharge pipeline 42 are provided. This on-off valve 6
0 is a directional control valve 4 related to actuators other than traveling
3, 44, 45, 46 or directional control valves 50, 5
Operation detecting means A for detecting whether or not 1, 52 are operated,
When no operation signal is output from B, C, D or the operation detecting means C, E, B, it is kept in the closed position shown in FIG.
It is adapted to be switched to the open position when the actuation signal is output. Further, the first branch passage 5 located downstream of the discharge pipe 41 of the first hydraulic pump 35 and the check valve 61.
The 9th part is connected by a second branch passage 102. The second branch passage 102 is provided with a flow rate control means, that is, the fixed throttle 100, and the first branch passage 59 is provided.
And the connection point between the second branch passage 102 and the fixed throttle 1 described above.
00, a check valve 101 for preventing backflow in the direction of the discharge pipe line 41 is provided.

The discharge line 4 of the second hydraulic pump 36
2 and the input port of the bucket directional control valve 51 are the conduit 1
A check valve 122 for preventing backflow in the direction of the discharge pipeline 42 is provided at an upstream position of this pipeline 120, and a fixed throttle 121 is provided at a downstream position thereof. Further, in FIG. 5, reference numeral 48 is a tank.

This prior art is aimed mainly at improving the performance of a combined operation in which a turning operation, a boom operation, an arm operation and the like are performed simultaneously with the traveling operation.

For example, when traveling and boom or traveling and arm are combined, the pressure oil of the first hydraulic pump 35 passes through the boom directional switching valve 45 or the arm directional switching valve 44, and the boom cylinder 55 or the arm cylinder. 5
4, the boom cylinder 55 or the arm cylinder 54 is driven, and the boom and arm (not shown) are driven. The operation of the boom direction switching valve 45 or the arm direction switching valve 44 is determined by the operation detecting means C.
Alternatively, the on-off valve 60 is switched to the open position by being detected by the operation detecting means B, and the second hydraulic pump 36
The pressure oil of the first branch passage 59, the left traveling direction switching valve 47
Is given to the left traveling motor 57 via the
The hydraulic oil of the hydraulic pump 36 is supplied to the right traveling motor 58 via the discharge pipe 42 and the right traveling direction switching valve 49, whereby both the left traveling motor 57 and the right traveling motor 58 are driven and not shown. The left crawler belt and the right crawler belt are driven to drive. The same applies to the combined operation of running and turning.

Further, during combined operation of traveling and bucket,
Through the pipe 120, the check valve 122, and the fixed throttle 121,
A part of the pressure oil of the second hydraulic pump 36 can be supplied to the bucket direction switching valve 51 and the bucket cylinder 56, and this combined operation can be realized.

Further, when the traveling alone operation is performed,
Since the on-off valve 60 is kept in the closed position, the entire amount of the pressure oil of the first hydraulic pump 35 is supplied to the left traveling motor 57 via the left traveling direction switching valve 47, and the pressure of the second hydraulic pump 36 is reduced. The entire amount of oil is supplied to the right traveling motor 58 via the right traveling direction switching valve 49, whereby the left and right crawler belts (not shown) are driven, and traveling is performed.

From such a traveling state, for example, the boom direction switching valve 4 included in the first switching valve group 39.
5, any one of the arm directional switching valve 44 and the turning directional switching valve 43 is operated, the pressure oil of the first hydraulic pump 35 is changed to the boom directional switching valve 45 and the arm directional switching valve 4.
4, the turning directional switching valve 43 is supplied to the corresponding directional switching valve, and the on-off valve 60 is switched to the open position. Therefore, the above-described operation is performed via the discharge conduit 42 and the first branch passage 59. Thus, the pressure oil of the second hydraulic pump 36 is supplied to the left traveling direction switching valve 47 and the right traveling direction switching valve 49. That is, the left traveling motor 57 and the right traveling motor 5
Only the pressure oil of the second hydraulic pump 36 is supplied to 8. Therefore, these left traveling motors 57,
The flow rate of the pressure oil supplied to the right traveling motor 58 is reduced to 1/2 as compared with the case of traveling alone until then, and the counter balance valves 90 and 91 are operated. Therefore, if no means is provided, it is large. You will be shocked. Figure 5
In the prior art shown in (1), a second branch passage 102 having a fixed throttle 100 and a check valve 101 is provided in order to reduce the shock. By appropriately setting the throttle amount of the fixed throttle 100, it is possible to supply a slight flow rate from the second branch passage 102 to the left traveling directional control valve 47 when switching from traveling alone to compound, and thereby to the traveling motor side. A sudden decrease in the supplied flow rate can be suppressed, and the above-mentioned shock can be alleviated.

[0013]

By the way, in the above-mentioned conventional technique, in order to further alleviate the shock during the combined operation of traveling and turning, the arm, or the boom, the throttle amount of the fixed throttle 100 is increased. When the left crawler belt driven by the left traveling motor 57 is placed in an environment such as a swamp where slipping or slipping occurs, the turning motor 53, the arm cylinder 54, and the boom cylinder 55 are set so that the vehicle can pass through. In a situation where the load on the left travel motor 57 side is smaller than the load on the other actuators other than the travel motor, the entire amount of the first hydraulic pump 35 is supplied to the left travel motor 57, and therefore the other actuators are supplied. This causes a problem that it becomes impossible to drive.

In order to prevent such a problem, if the throttle amount of the fixed throttle 100 is set in advance so that a small flow rate can pass, driving of another actuator can be realized in the above-mentioned case, but It is unavoidable that the shock will increase.

That is, in the prior art shown in FIG. 5, the fixed throttle 100 provided in the first branch passage 102.
Of the throttle amount, that is, the flow rate control characteristic is uniquely set, the shock generated during composite driving of the travel motor and other actuators is alleviated, and other than the travel motor during composite driving. There is a problem that it is impossible to achieve both of the prevention of the inability to drive the actuator of the above.

The present invention has been made in view of the above-mentioned circumstances in the prior art, and its purpose is to alleviate a shock generated when the traveling motor and other actuators are combined, and to eliminate a traveling motor during the combined driving. Another object of the present invention is to provide a hydraulic circuit for a civil engineering / construction machine that can both prevent the occurrence of a situation in which another actuator cannot be driven.

[0017]

In order to achieve this object, the invention comprises a plurality of hydraulic pumps and a first of these hydraulic pumps which is formed with respect to the first hydraulic pump. The switching valve group includes one of the left and right traveling directional switching valves, the turning directional switching valve, and
Including a boom directional control valve and an arm directional control valve,
The second switching valve group formed for the second hydraulic pump of the plurality of hydraulic pumps includes the other traveling directional switching valve, the second boom directional switching valve, and the second arm directional switching valve. At least one of the directional control valves, and in the first directional control valve group, the turning directional control valve, the boom directional control valve, and the arm directional control valve have priority over the one traveling directional control valve. Is connected to the first hydraulic pump at an upstream position where it can receive pressure oil, and in the second directional control valve group, the other traveling directional control valve is connected to the second boom directional control valve and the second directional control valve. The second hydraulic pump is connected to the second hydraulic pump at a position upstream from which at least one of the second arm directional control valves can receive pressure oil, and the second hydraulic pump and the one traveling directional control valve are connected. In the first branch passage that is selectively opened and closed Next, in the hydraulic circuit of the civil engineering / construction machine, in which the first hydraulic pump and the one traveling directional control valve are connected by a second branch passage having a flow control means and a check valve, the flow control is performed. The means is a flow rate variable control means, and an output means for outputting a signal relating to the operation of an actuator other than the traveling motor and controlling the flow rate flowing from the flow rate variable control means, and the output means. The flow rate variable control means is driven according to a signal so as to change from a small throttle amount to a large throttle amount.

[0018]

Since the present invention has the above-mentioned structure, when the traveling motor and the other actuator are combinedly driven, the drive means controls the flow rate variable control means with a small throttle amount in accordance with the signal output from the output means. Drive so that the flow rate control characteristic changes to a large throttle amount, and when the signal is output from the output means along with the driving of another actuator, the throttle amount of the flow rate variable control means is small. The flow rate flowing through the second branch passage is relatively large, and it is possible to prevent a rapid decrease in the flow rate supplied from the first hydraulic pump to the traveling motor via the second branch passage. The shock can be alleviated, and then the throttle amount of the flow rate variable control means changes so as to increase. Therefore, the flow rate flowing through the second branch passage decreases, and accordingly Although the flow rate to be supplied to the traveling motor is reduced through the second branch passage, the flow rate supplied from the first hydraulic pump to the other actuator is increased,
Even when the load pressure of the traveling motor is lower than the load pressures of the other actuators, the other actuators can be reliably driven without causing the other actuators to be unable to be driven. At this time, the pressure oil of the second hydraulic pump is supplied to the traveling direction switching valve via the first branch passage and the opening / closing valve switched to the open position, whereby the left traveling direction switching valve and the right traveling direction switching valve are supplied. The pressure oil of the second hydraulic pump can be supplied to both the traveling direction switching valves. In this way, the combined drive of the travel motor and the other actuator can be performed, and the shock generated during the combined drive of the travel motor and the other actuator can be alleviated, and the actuator other than the travel motor during the combined drive. It is possible to realize both of the prevention of the occurrence of the inability to drive.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a hydraulic circuit for civil engineering and construction machinery according to the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a hydraulic circuit of a hydraulic excavator given as a first embodiment of the present invention, and is drawn corresponding to FIG. 5 described above. In FIG. 1 showing the first embodiment, the same components as those shown in FIG. 5 described above are designated by the same reference numerals.

That is, even in the first embodiment, a plurality of hydraulic pumps, for example, the first hydraulic pump 35 and the second hydraulic pump 36, and these hydraulic pumps are provided as in the case shown in FIG. 5 described above. A prime mover 37, 3 for driving 35, 36
8, relief valves 62 and 63 for setting the discharge pressures of the hydraulic pumps 35 and 36, and the discharge line 4 of the first hydraulic pump 35.
The first switching valve group 39 connected to No. 1 and the second switching valve group 40 connected to the discharge pipe line 42 of the second hydraulic pump 36 are provided.

The first directional control valve group 39 has a turning directional control valve 43 at the upstream position, and the arm directional control valve 44, the boom directional control valve 45, and the standby directional control valve 43 in that order downstream thereof. 46, one of the left and right, that is, the left traveling direction switching valve 47, and the turning direction switching valve 43.
Is connected to a swing motor 53 that drives a swing body (not shown), the direction switch valve 44 for arms is connected to an arm cylinder 54 that drives an arm (not shown), and the direction change valve 45 for booms is a boom cylinder that drives a boom (not shown). 5
5, the left traveling direction switching valve 47 is connected to a left traveling motor 57 that drives a left crawler belt (not shown). Further, the second switching valve group 40 has the other of the left and right, that is, the right traveling direction switching valve 49 at the upstream position, and the second boom direction switching valve 50 and the bucket switching valve are sequentially provided downstream thereof. Direction switching valve 51, second arm direction switching valve 5
2, the right traveling directional control valve 49 is connected to a right traveling motor 58 that drives a right crawler belt (not shown), and
The boom direction switching valve 50 is connected to a boom cylinder 55 that drives a boom (not shown), the bucket direction switching valve 51 is connected to a bucket cylinder 56 that drives a bucket (not shown), and a second arm direction switching valve 52. Is connected to an arm cylinder 54 that drives an arm (not shown).

Left traveling direction switching valve 47 and left traveling motor 5
A counter balance valve 90 is provided between the
A counter balance valve 91 is provided between the right traveling direction switching valve 49 and the right traveling motor 58.

A discharge line 42 of the second hydraulic pump 36,
A first branch passage 59 is connected to the input port of the left traveling directional control valve 47, and the first branch passage 59 is connected to the first branch passage 59.
An on-off valve 60 that opens and closes the first branch passage 59, and a check valve 61 that is provided downstream of the on-off valve 60 and that prevents a backflow toward the discharge conduit 42 are provided.
Is a direction switching valve 43 related to an actuator other than traveling,
44, 45, 46 or directional control valves 50, 51, 5
Operation detecting means A, B for detecting whether or not 2 has operated,
When the operation signal is not output from C, D or the operation detecting means C, E, B, the closed position shown in FIG. 1 is maintained, and when the operation signal is output, it is switched to the open position. Further, the discharge pipe 41 of the first hydraulic pump 35 and the first branch passage 59 located downstream of the check valve 61.
The part is connected by a second branch passage 102. Also,
The discharge conduit 42 of the second hydraulic pump 36 and the input port of the bucket directional control valve 51 are connected by a conduit 120, and a reverse flow in the direction of the discharge conduit 42 is provided at an upstream position in this conduit 120. A non-return valve 122 is provided to prevent this, and a fixed throttle 121 is provided at the downstream position. In FIG. 1, reference numeral 48 is a tank. The above is equivalent to that shown in FIG. 5 described above.

Particularly, in the first embodiment, the flow rate variable control means 100a is provided in the second branch passage 102, and the discharge pipe is provided in the second branch passage 102 portion downstream of the flow rate variable control means 100a. A check valve 101 is provided to prevent backflow in the direction of the passage 41. Flow rate variable control means 1 described above
00a is from a fully open position or a maximum aperture position having a predetermined maximum opening area (position giving a small aperture amount) to a fully closed position or a minimum aperture position having a predetermined minimum aperture position (position giving a large aperture amount). Although it operates so as to change continuously, in FIG. 1 it is drawn to have three positions of fully open, throttle, and fully closed for ease of explanation. The pressure receiving chamber provided with a spring for urging the spool provided in the flow rate control means 100a in the opening direction is the throttle 10
It is connected to the tank 48 via 3. The other pressure receiving chamber is connected to the pilot hydraulic pressure source 105 via the throttle 104. Further, the throttle 104 and the pilot hydraulic power source 105
The pilot line portion located between the two is kept in the closed position when no operation signal is output from the above-mentioned operation detecting means A, B, C, D, E, and in the open position when the operation signal is output. A switching valve 106 that can be switched to is provided.

The above-mentioned operation detecting means A, B, C, D, E
Is a signal related to the operation of an actuator other than a traveling motor (not shown), that is, the swing motor 53, the arm cylinder 54, the boom cylinder 55, and the bucket cylinder 56, and outputs a signal for controlling the flow rate flowing from the variable flow rate control means 100a. It constitutes the output means to perform. In addition, the switching valve 106, the pilot hydraulic pressure source 105,
The throttles 103 and 104 change the flow rate control means 100a from a small throttle amount to a large throttle amount for a predetermined time in accordance with the operation signals output from the output means, that is, the operation detecting means A, B, C, D and E. The driving means is configured to drive so as to change the quantity.

In the embodiment constructed as described above, when the traveling alone operation is performed, the opening / closing valve 60 is kept in the closed position as in the prior art shown in FIG. The total amount of pressure oil of the first hydraulic pump 35 is supplied to the left traveling motor 57 via the left traveling direction switching valve 43, and the entire amount of pressure oil of the second hydraulic pump 36 is transmitted via the right traveling direction switching valve 49. Is supplied to the right traveling motor 58, and the left and right crawler belts (not shown) are driven thereby to travel.

From such a traveling state, for example, the turning direction switching valve 43, the arm direction switching valve 44, and the boom direction switching valve 43, which are included in the first switching valve group 39 for the purpose of a combined operation of turning, an arm, and a boom, are included. When any one of the direction switching valves 45 is operated, the operation detecting means A, B or C detects the operation, and outputs a corresponding operation signal to the switching valve 106 or the on-off valve 6.
Output to 0. As a result, the switching valve 106 and the opening / closing valve 60
Is switched to the left position in FIG. 1, ie the open position.

By switching the switching valve 106 to the open position, the pilot pressure of the pilot hydraulic power source 105 is applied to the drive unit of the flow rate variable control means 100a through the throttle 104, and the spool moves against the force of the spring. However, the pilot pressure in the pressure receiving chamber in which the spring is provided is reduced by 1
Returned to the tank 48 through 03, the flow rate variable control means 100a is continuously operated from the open position shown in FIG. 1 where the throttle amount is the minimum to the closed position where the throttle amount is the middle position and the throttle position where the throttle amount is the maximum position. Is switched to. Along with this, the first hydraulic pump 35 discharges and the discharge pipe line 4
First and second branch passages 102, flow rate variable control means 100
a, the flow rate supplied to the left traveling direction switching valve 47 via the check valve 101 gradually decreases from the maximum flow rate, and becomes 0 when the flow rate variable control means 100a is switched to the closed position. In this way, as the flow rate supplied to the left traveling directional control valve 47 sequentially decreases to 0, the turning directional control valve 43 and the arm directional control valve 44 to which the pressure oil of the first hydraulic pump 35 corresponds. , The boom directional control valve 45, and thereby the revolving structure, arm,
Alternatively, the boom can be driven.

Further, by switching the open / close valve 60 to the open position, a part of the pressure oil of the second hydraulic pump 36 is passed to the left through the first branch passage 59, the open / close valve 60 and the check valve 61. The pressure oil of the second hydraulic pump 36 is guided to the directional control valve 47, whereby the pressure oil of the second hydraulic pump 36 is guided to both the left traveling directional control valve 47 and the right traveling directional control valve 49, and the left and right traveling motors (not shown) are driven. You can

In the combined operation of traveling and the bucket, a portion of the pressure oil of the second hydraulic pump 36 is transferred to the bucket directional switching valve 51 via the pipe 120, the check valve 122, and the fixed throttle 121. , But can be supplied to the bucket cylinder 56, which is the same as that of the conventional technique shown in FIG. 5 described above.

In the first embodiment constructed as described above, the flow rate variable control means 1 is used, for example, when shifting from traveling alone to traveling and turning, a boom, or a combined operation of arms.
By driving 00a, the flow rate introduced to the left traveling directional switching valve 47 is gradually reduced to 0 within a predetermined time, so that the shock can be alleviated, and the flow rate variable control means 100a is switched to the closed position. If the left traveling motor 57 controlled by the left traveling direction switching valve 47 has a lower load than the side of the swing motor 53, the arm cylinder 54, or the boom cylinder 55, these swing motors 53 are controlled. The pressure oil can be supplied to the arm cylinder 54, the boom cylinder 55, and the actuators other than these traveling motors cannot be driven, and the unillustrated revolving structure, arm, or boom can be driven together with the traveling motor. .. In addition, the above-mentioned predetermined time can be set to, for example, about 1 second, and therefore, the above-mentioned alleviation of shock and prevention of occurrence of inoperability of actuators other than the traveling motor can be realized almost at the same time.

Further, in the above, the turning direction switching valve 43, the arm direction switching valve 44, the boom direction switching valve 45, etc. are switched by the direct-acting operation lever, and the operation detecting means is operated by the operation detecting means. Although the operation of the operation lever is detected, the directional control valves may be operated by an electric lever, and the operation detecting means may extract an electric signal generated by the operation of the electric lever. Alternatively, the directional control valve may be of a pilot operated type, and the operation detecting means may take out a pilot pressure signal generated in accordance with the operation of the pilot valve.

FIG. 2 is a circuit diagram showing the configuration of the second embodiment of the present invention, FIG. 3 is a diagram showing the functional relationships stored in the arithmetic means provided in the second embodiment shown in FIG. 2, and FIG. FIG. 4 is a diagram showing characteristics of a proportional pressure reducing valve provided in the second embodiment shown in FIG.

In the second embodiment, the output means is the turning direction switching valve 43, the arm direction switching valve 44, the boom direction switching valve 45, the spare direction switching valve 46, or the second boom direction. Switching valve 50, bucket directional switching valve 51,
The operation amount detection means A1, B1 for detecting the operation amounts of the second arm directional control valves 52 and outputting the operation amount signals, respectively.
C1, D1, or C1, E1, B1 and, for example, FIG.
As shown in FIG. 5, the functional relationship between the operation amounts of the directional control valves 43, 44, 45 and the output signal values is stored in advance, and the operation amount signals output from the operation amount detecting means A1, B1, C1, D1, E1 are used as the operation amount signals. The corresponding output signal value is obtained from the functional relationship shown in FIG. 3, and a signal having the output signal value is output as a control signal for controlling the driving of the driving means. In the functional relationship shown in FIG. 3, the output signal value increases as the operation amount (%) increases, and the output signal value gradually increases within a predetermined time after the operation amount signal is input. This is a functional relationship that will later result in a constant magnitude output signal value. Also, the operation amount is 100%
Indicates a full stroke, and the operation amount of 20% indicates a stroke of 20% during fine operation.

Further, the driving means for driving the variable flow rate control means so as to change from the small throttle amount (large opening area) to the large throttle amount (small opening area) is the pilot hydraulic pressure source 105 and the pilot hydraulic pressure source 105. The proportional pressure reducing valve 201 is provided in a pilot line that connects the drive unit of the flow rate variable control means 100a and is driven according to a control signal output from the computing means 200. Other configurations are the same as those in the first embodiment described above.

In the second embodiment constructed as described above, when the operation is shifted from the independent operation to the combined operation of traveling and turning, traveling and boom, and traveling and arm, the corresponding turning direction switching valve 43, Along with the operation of either the arm direction switching valve 44 or the boom direction switching valve 45, the operation amount signals corresponding to the operation amount detecting means A1, B1, and C1 to the drive unit of the opening / closing valve 60 and the calculating means 200 are transmitted. Is output,
The on-off valve 60 is switched to the open position. This on-off valve 60
Is switched to the open position, a part of the pressure oil of the second hydraulic pump 36 is guided to the left traveling directional control valve 47 through the first branch passage 59, the opening / closing valve 60, and the check valve 61. Left traveling direction control valve 47, right traveling direction control valve 49
The pressure oil of the second hydraulic pump 36 is introduced to both of the above, and the vehicle can continue to travel by then.

Further, the calculating means 200 outputs the control signal having the output signal value according to the functional relation shown in FIG.
01 to the drive unit, and the pilot hydraulic power source 1
Flow rate control means 1 from 05 via proportional pressure reducing valve 201
The pilot pressure oil having the flow rate shown in FIG. 4 is supplied to the drive unit of 00a. Thereby, the flow rate variable control means 100a
2 is continuously switched during a predetermined time from the open position shown in FIG. 2 where the diaphragm amount is the minimum to the switching position where the diaphragm amount is large. Accordingly, like the first embodiment described above,
The flow rate discharged from the first hydraulic pump 35 and supplied to the left traveling directional control valve 47 via the discharge pipeline 41, the second branch passage 102, the flow rate variable control means 100a, and the check valve 101 is as described above. It gradually decreases from the maximum flow rate within a predetermined time,
On the other hand, the turning direction switching valve 43 and the arm direction switching valve 4
4, or the boom directional control valve 45 is supplied with a sufficient flow rate discharged from the first hydraulic pump 35 after a predetermined time, and the turning, the arm, or the boom can be operated. In this way, desired traveling and turning, combined operation of the arm or boom can be realized.

In this case, for example, when the above-mentioned operation amount is 20%, it is when a fine operation of the swing, arm, or boom is intended. Therefore, the swing motor 5
3, arm cylinder 54, or boom cylinder 55
The required flow rate is small, and the flow rate of the pilot pressure oil supplied from the proportional pressure reducing valve 201 to the drive unit of the variable flow rate control means 100a becomes smaller than that in the case where the operation amount is 100%. Along with this, the flow rate variable control means 100a does not become fully closed even after the predetermined time, and the first hydraulic pump 3
A part of the pressure oil of No. 5 is supplied to the left traveling directional switching valve 47 via the flow rate variable control means 100a and the check valve 101, so that the above-mentioned shock can be suppressed more reliably and the first hydraulic pressure can be suppressed. The pressure oil of the pump 35 is effectively used for traveling, and complex operations such as traveling and fine turning operations, fine arm operations, and fine boom operations are possible.

Even in the second embodiment having the above-mentioned structure, the flow rate can be changed when the traveling is changed from the traveling alone to the traveling and turning, the boom, or the combined operation of the arms, as in the first embodiment described above. By driving the control means 100a, the flow rate guided to the left traveling directional switching valve 47 is gradually reduced within a predetermined time, so that the shock can be alleviated, and the variable flow rate control means 100a is driven. Regardless of whether the left traveling motor 57 controlled by the left traveling direction switching valve 47 has a lower load than the side of the swing motor 53, the arm cylinder 54, or the boom cylinder 55, these swing motor 53, arm cylinders 54 can supply pressure oil to the boom cylinder 55 or the boom cylinder 55, and the actuators other than these traveling motors cannot be driven. Times body, it is possible to drive arm, or the boom the running motor.

The functional relationships set in the arithmetic means 200 are not limited to those shown in FIG. That is, in the above, the turning directional control valve 43, the arm directional control valve 44, and the boom directional control valve 45 have a common functional relationship.
The functional relationship corresponding to each directional control valve 43, 44, 45 is
It may be set individually according to the work contents performed by the turning operation, the arm operation, or the boom operation. Further, the functional relationship may be one that takes into consideration complex operations such as turning and boom raising, boom lowering performed during traveling, and boom and arm operations performed during traveling.
In any case, a functional relationship that can change the flow rate variable control means 100a from a small throttle amount (large opening area) to a large throttle amount (small opening area) at the time of combined driving with traveling is sufficient.

[0041]

Since the present invention is configured as described above, the shock generated when the traveling motor and the other actuators are combined is alleviated, and the actuators other than the traveling motor are driven during the combined driving. Both the prevention of the occurrence of an impossible situation can be realized, and there is an effect that superior operability can be obtained as compared with the conventional case.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration of a first embodiment of a hydraulic circuit of a civil engineering / construction machine of the present invention.

FIG. 2 is a circuit diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 3 is a diagram showing a functional relationship stored in a computing means provided in the second embodiment shown in FIG.

FIG. 4 is a diagram showing characteristics of a proportional pressure reducing valve provided in the second embodiment shown in FIG.

FIG. 5 is a circuit diagram showing an example of a hydraulic circuit of a conventional civil engineering / construction machine.

[Explanation of symbols]

 35 1st hydraulic pump 36 2nd hydraulic pump 39 1st switching valve group 40 2nd switching valve group 41 discharge pipe line 42 discharge pipe line 43 turning direction switching valve 44 arm direction switching valve 45 boom direction Changeover valve 46 Spare direction changeover valve 47 Left traveling direction changeover valve 49 Right traveling direction changeover valve 50 Second boom direction changeover valve 51 Bucket direction changeover valve 52 Second arm direction changeover valve 53 Swing motor 54 Arm cylinder 55 Boom cylinder 56 Bucket cylinder 57 Left traveling motor 58 Right traveling motor 59 First branch passage 60 On-off valve 61 Check valve 100a Flow rate variable control means 101 Check valve 102 Second branch passage 103 Fixed throttle 104 Fixed throttle 105 Pilot hydraulic power source 106 Switching valve 200 Computing means 201 Proportional pressure reducing valve A Operation detection Means B Operation detecting means C Operation detecting means D Operation detecting means E Operation detecting means A1 Operation amount detecting means B1 Operation amount detecting means C1 Operation amount detecting means D1 Operation amount detecting means E1 Operation amount detecting means

Claims (3)

[Claims] 1. A first switching valve group having a plurality of hydraulic pumps, the first switching valve group being formed with respect to a first hydraulic pump among these hydraulic pumps, is provided for one of left and right traveling. A directional valve, a directional valve for turning,
Including a boom directional control valve and an arm directional control valve,
The second switching valve group formed for the second hydraulic pump of the plurality of hydraulic pumps includes the other traveling directional switching valve, the second boom directional switching valve, and the second arm directional switching valve. At least one of the directional control valves, and in the first directional control valve group, the turning directional control valve, the boom directional control valve, and the arm directional control valve have priority over the one traveling directional control valve. Is connected to the first hydraulic pump at an upstream position where it can receive pressure oil, and in the second directional control valve group, the other traveling directional control valve is connected to the second boom directional control valve and the second directional control valve. The second hydraulic pump is connected to the second hydraulic pump at a position upstream from which at least one of the second arm directional control valves can receive pressure oil, and the second hydraulic pump and the one traveling directional control valve are connected. In the first branch passage that is selectively opened and closed Next, in the hydraulic circuit of the civil engineering / construction machine, in which the first hydraulic pump and the one traveling directional control valve are connected by a second branch passage having a flow control means and a check valve, the flow control is performed. The means is a flow rate variable control means, and an output means for outputting a signal relating to the operation of an actuator other than the traveling motor and controlling the flow rate flowing from the flow rate variable control means, and the output means. A hydraulic circuit for civil engineering / construction machinery, comprising: a drive unit that drives the variable flow rate control unit so as to change from a small throttle amount to a large throttle amount in response to a signal. 2. The output means is an operation detecting means for detecting an operation of an actuator other than the traveling motor and outputting an operation signal, and the drive means is a predetermined one according to the operation signal output from the operation detecting means. 2. The hydraulic circuit for civil engineering / construction machinery according to claim 1, wherein the variable flow rate control means is driven so as to change the flow rate control characteristic over time. 3. An operation amount detecting means for detecting an operation amount of a direction switching valve for an actuator other than the traveling direction switching valve and outputting an operation amount signal, and an output means for an actuator other than the traveling direction switching valve in advance. A signal having the output signal value, which stores the functional relationship between the manipulated variable of the directional control valve and the output signal value, obtains the output signal value corresponding to the manipulated variable signal output from the manipulated variable detecting means from the functional relationship, 2. The hydraulic circuit for civil engineering / construction machinery according to claim 1, further comprising: a computing unit that outputs as a control signal for controlling the driving of the driving unit.