JPS61151333A - Hydraulic circuit device for construction machine - Google Patents

Abstract

PURPOSE:To control a speed and a flow rate, by a method wherein hydraulic circuits for a boom, an arm, a bucket, and right and left running hydraulic circuits are closed, each circuit is short-circuited, a slewing hydraulic circuit is also closed, and pressure from each pump is distributed according to the order of priority. CONSTITUTION:A boom hydraulic circuit A, an arm hydraulic circuit C, a bucket bottom damp hydraulic circuit D, a bucket hydraulic circuit E, and left and right running hydraulic circuits B and F make one group, the boom circuit A, the arm circuit C, the bottom circuit D, the bucket circuit E, and the left and right running hydraulic circuits B and F are short-circuited through a cross over circuit 3 to form a closed circuit. Further, slewing hydraulic circuits G and H form a closed circuit. A control circuit R, distributing a flow rate to each actuator according to the previously determined order of priority, is located to a hydraulic pump feeding an oil pressure to each actuator. This enables control of the speed of each actuator.

Description

[Detailed description of the invention] Industrial applications The present invention relates to a hydraulic circuit device for construction machinery.

BACKGROUND OF THE INVENTION Conventional hydraulic circuit devices of this type have either a completely open circuit, a partially closed circuit, or an all-closed circuit for each actuator.

Problems to be Solved by the Invention However, with completely open circuits, it is difficult to recover and reuse energy, and with partially closed circuits, it is possible to recover and reuse energy only in this partially closed circuit part. It was nothing more than

In addition, in the case of an all-closed circuit for each of the 7 actuators, it is possible to recover and use energy from all circuits, but since each actuator has a completely independent circuit, in order to cover the pump discharge amount required for each of the 7 actuators, each My friend needed a large capacity bong.

The present invention has been made in view of the above circumstances, and its purpose is to create a completely closed circuit, and moreover, a cross-over closed circuit, in which the boom hydraulic circuit, the arm hydraulic circuit C, and the bottom dump fluid are connected to each other. The pressure circuit, the packet hydraulic circuit E, and the left and right traveling hydraulic pressure circuits B and F are merged and distributed as necessary, and the required pump discharge amount for each actuator is covered by a combination of small-capacity pumps. , and also to enable the operator to control the flow rate distribution to each actuator according to nine predetermined priorities and the speed of any actuator selected by the operator.

Next Means and Effects for Solving the Problems The present invention provides a pool hydraulic pressure circuit A, an arm hydraulic pressure circuit C, a bottom dump hydraulic pressure circuit, a packet hydraulic pressure circuit E, and left and right traveling hydraulic pressure circuits B and F. and boom hydraulic pressure circuit A1 arm hydraulic pressure circuit C1 bottom dump hydraulic pressure circuit D1
Packet hydraulic circuit E1 Left and right traveling hydraulic pressure circuits B and F are short-circuited by crossover circuit S to form a closed circuit, swing hydraulic circuits G and H are closed circuits, and priority is determined in advance by the control lever signal. It is configured with a control circuit R that distributes the flow rate to each actuator according to the order and controls the speed of any actuator according to the magnitude of the control lever signal, and includes a boom hydraulic pressure circuit A, an arm hydraulic pressure circuit C, and a bottom dump The hydraulic pressure circuit, the packet hydraulic circuit E, and the left and right travel hydraulic pressure circuits B and F are merged and distributed as necessary, and the required pump discharge amount for each actuator is achieved by combining small-capacity pumps. In addition, the flow rate distribution to each actuator according to a predetermined priority order and the speed of any actuator selected by the operator are controlled.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings. Figure 1 shows a construction vehicle. The construction vehicle 1 is equipped with a lower traveling body 2), and the lower traveling body 2 is connected to an upper rotating body 4 via a turning mechanism 3.

The swing mechanism 3 includes a swing motor 5α as an actuator α.
, 56. The upper revolving body 4 is provided with a poom 6 that can be raised and lowered, and the upper revolving body 4 (is provided with a poom cylinder 7 as an actuator b for raising and lowering the pool 6. The poom 6 has an arm g. The arm 8 is provided with an arm cylinder 9 as an actuator C that operates the arm 80 to swing back and forth.The arm 8 is provided with a bucket (JO) that can swing back and forth. Arm 8 and packet 10 have links I+, +
2 are connected, and 11. A packet cylinder 13 as an actuator d is attached to +2, and the piston rod 14 of the packet cylinder 13 is connected to the pin 1 of the poom 6.
It is connected by 5.

The packet 10 is equipped with a movable part t6 (bucket) 1
0 is provided with a bottom dump cylinder 17 as an actuator e that opens and closes the movable part 16. 18.1
Reference numeral 9 represents left and right travel motors serving as actuator f1g.

21. 22, 23, 24, 25, 26 are variable displacement first to sixth pumps, and the first pump 21 is connected to the pipe line 27.2.
It is connected to the head side and rod side of the boom cylinder 7 through a pipe 8, and a switching valve 29 and a flow regulating valve FIB are connected between the pipes 27 and 28.

A p + Hs suction safety valve 31 and a neutral bypass valve 32 are provided, and a pilot check valve Lt6. Lt8. Xat5. Li2. B.O.
2゜Bt)4. There are 8 BOI*BO3s, which constitute the boom hydraulic circuit.

The first pump 21 is connected to the left travel motor 1g via pipes 33 and 34, and a switching valve 2 is connected between the pipes 33 and 34.
9. Flow'! i' regulating valves FIH, FIB, neutral bypass valve 32, valves 33', 34' are provided,
In addition, pilot check valve Lf2* is installed in pipes 33 and 34.
Ij4sL! 1sLt3 are provided, and these constitute a left travel hydraulic pressure circuit B.

The inlet sides of the flow rate regulating valves FIH, FIB and the inlet side of the suction safety valve 3I are connected to the discharge side of the charge pump 37 via pipes 3g, 39.

The second pump 22 is connected to the head side and the rond side of the arm cylinder 9 via a pipe line 40.4+.
Between 41 and 41 is a switching valve 42 and a flow rate adjustment valve? 21-1. P2
B, suction safety valve 44 and neutral bypass valve 45
A pilot check valve Ar2. is provided in the conduit 40.4+. ArLAft and Ar1 are provided,
These constitute an arm hydraulic circuit C.

The fifth pump 25 is connected to the bottom dump cylinder +7 via pipes 46 and 47, and between the pipes 46 and 47 there is a switching valve 4g and a flow rate regulating valve F'5H.

F5B, neutral bypass valve 50. Inhalation safety valve 5
A pilot check valve Bt2.1 is provided in the pipe line 46.47. Bt4, Btl, Bl! 3 are provided, and these constitute the bottom dump hydraulic circuit. rt', a・t, F2B.

Incidentally, the inlet side of the flow rate adjustment *,..., FsH, F5B and the inlet side of the suction safety valve 44.51 are connected to the discharge side of the charge pump 37 via conduits 52, 52', 53.53'. The sixth pong 26 is connected to the head side and the rond side of the packet cylinder 13 via pipes 54 and 55, and between the pipes 54 and 55 there is a switching valve 56 and a flow rate regulating valve F6.
1(,F'6B.

A suction safety valve 58 and a neutral bypass valve 59 are provided, and a pilot check valve t6.几t8. R, t5.几t7, BU2,
BU4.

BUI and BU3 are provided, and these constitute a packet hydraulic circuit E.

The sixth bomb 26 is connected to the right travel motor 19 via pipes 62 and 63, and the pipe w! There is a switching valve 5 between 62° and 63.
6. Flow rate adjustment valves F6H, F6B.

A neutral bypass valve 59 and a pulp 64° 65 are provided, and pilot check valve holes t 3 , nt I , B, t 4 , nt 3 are provided in the pipes 62 and 63, and these connect the right travel hydraulic pressure circuit. It constitutes F.

In addition, flow! The inlet sides of the regulating valves F6H and 76B and the inlet side of the suction safety valve 5g are connected to the discharge side of the charge pump 37.

The swash plate angle control section of the tth to sixth bombs 2r to 26 is connected to the servo cylinder g (-16 and connected to 8 cylinders, and each servo cylinder ε
1 to 86 are servo valves 77 (noho) 77G,
The boat 77c of the servo valve 77 is connected to the pilot pump 7o via the pipe go, and the boat 77 of each servo valve 77 (L is the pipe line 87 leads to the tank.

S is a crossover circuit. The boom hydraulic circuit line 27 is connected to the arm hydraulic circuit C line 4o via the short-circuit IJ line +00, and this short-circuit line 100 is connected to the pilot check valve PI2g! .

PI2c is provided.

The pipe line 4o of the arm hydraulic pressure circuit C is connected to the pipe line 46 of the bottom dump hydraulic pressure circuit via a short-circuit pipe line 103, and pilot check valves P25α, P are connected to this short-circuit pipe line 103.
25C is provided.

The bottom dump hydraulic circuit line 46 is connected to the packet hydraulic circuit B line 54 via a short circuit line 106.
Pilot check valves P56α and P5 are installed in the short-circuit pipe 106.
6c is provided. Also, boom hydraulic pressure @F@h V path 28
is connected to the pipe line 41 of the arm hydraulic pressure circuit C via the short-circuit pipe line 109.
The short circuit line 109 is connected to the pilot check valves P12b and PJ%.

The pipe line 41 of the arm hydraulic pressure circuit C is connected to the pipe line 47 of the bottom dump hydraulic pressure circuit via a short-circuit pipe line 112, and pilot check valves P25b and P2 are connected to this short-circuit pipe line 2.
5d is provided. Bottom dump hydraulic circuit pipe line 47
is the packet HfE@Pipe 5 of Route E via the short-circuit pipe ■5
5, pilot check valve gates 6b and P56d are provided in this short-circuit pipe II5.

The boom hydraulic circuit line 27 is connected to the bottom dump hydraulic circuit line 46 via a short-circuit line 118, and pilot check valves PI5b and P15 are connected to the short-circuit line 118.
C is provided. The boom hydraulic circuit's pipe 28 is connected to the bottom dump hydraulic circuit's pipe 4 via the short-circuit pipe 21.
7, and a pilot check valve P15b is connected to the short circuit line 121.

P15d is provided.

The pipe line 27 of the arm hydraulic pressure circuit A is connected to the pipe line 54 of the packet hydraulic pressure circuit E via a short-circuit pipe line 124, and pilot check valves P16α and PI6 are connected to this short-circuit pipe line 124.
C is provided.

The arm hydraulic circuit's 28 pipes are connected to the pipe 55 of the packet hydraulic circuit E via a short-circuit pipe 127, and pilot check valves P16b and P16 are connected to this short-circuit pipe 127.
d is a provision.

The pipe 40 of the arm hydraulic pressure circuit C is connected to the pipe 54 of the packet hydraulic pressure circuit E via a short-circuit pipe 130, and the short-circuit pipe 130 is provided with pilot check valves P25α and P25C. , the pipe 41 of the arm hydraulic pressure circuit C is connected to the pipe 55 of the packet hydraulic pressure circuit E via the short-circuit pipe 133, and the pilot check valve P is connected to the short-circuit pipe 133.
25b and P251f are provided.

The third pump 23 is connected to one of the swing motors 5α via pipes 136 and 137, and between the pipes I36 and 137 there are check valves 138 and 139, a switching valve 140, a neutral bypass valve 141, and a valve 142. 143 is provided, and pilot check valves 144, 145 are provided in the main pipes 136, 137, and these constitute a 10,000-swivel hydraulic pressure circuit G.

Further, the fourth pump 24 is connected to the other swing motor 5b via pipes 146 and 147.
In between are check valves 148 and 149, switching valve +50, neutral bypass valve 151, and knobs 152 and 153.
are provided, and pilot check valves 154 and 155 are provided in the conduits 146 and 147, and these constitute the other swing hydraulic circuit H. And check valves 138, 139° 14LI4 for both swing hydraulic pressure circuits G and H
9 is connected to the discharge side of the charge pump 37 through a conduit 156.
, 157, and the switching valves 140, 1
50 boats 140α and 150α are connected to a tank 158 via a relief valve 159, and the pipes 136 and 137 of one swing hydraulic pressure circuit G are connected to the other swing hydraulic pressure circuit via short-circuit pipes 160 and 161. These are connected to conduits 146 and 147 of H, and together they constitute a rotating closed circuit J.

Each 1st to 6th bump 2+, 22, 23.24° 25.2
The discharge amount control and direction control of 6 are performed by a control circuit shown in FIG. In the control circuit R, f70 is a computing unit (microcomputer), +71 is an AD converter, and 172 is an amplifier, which converts the position signal α of the control lever 173 and the discharge pressure signals of the first to sixth pumps 21 to 26 to AD conversion. vessel 171
is input to the calculator 170K as a digital signal, and in this calculator 170, the sum of the pump output +7
)-2 control, when the control levers 173 of each pump are operated simultaneously, the discharge amount of each pump and the opening/closing of each pilot check valve are arranged according to nine predetermined priorities.

The calculation unit 170 outputs the pump discharge amount signal C and each pump 2.
The flow distribution signal d of each actuator 1 to 26 is outputted to control the servo valve 77 and the on-off valve 174 of each pilot check valve.

Next, the operation will be explained.

11) In the case of boom independent operation: ■ When the boom is up, pilot pressure is generated by the boom up signal from the control lever 173, and the pilot check valves Bl)l and Bl open. On the other hand, for the first pump 21, a pump discharge amount signal and a discharge direction control signal proportional to the lever signal enter the servo valve 77 of the first pump 21, and the pump discharge amount and direction are determined and discharged to the head side of the boom cylinder 7. Oil is supplied.

Since it is alone on the boom, the first Second pump 21
, 22 is connected to the pilot check valve PI2C.
, P12b, and these are opened. Also number 1. Pilot check valve PI30°P15b connected to the fifth pump 21°25 %1st. Pilot check valve P1 to which the 6th pump 21.26 is connected
Pilot pressure is also applied to 6C and P16b, which open them.

This leads to the first. Second. 5th #6th pump 2+, 22,
The discharge oil of 25 and 26 is supplied to the head side of the boom cylinder 7.

The return oil from the rod side of the boom cylinder 7 is passed through the rod side pipe line 2gj41. Returned to a7,55.

At this time, the difference in oil amount between the head 11111 of the boom cylinder 7 and the rod side is replenished from the charge pump 37.

■ When the boom (lower) is on, the amount of oil discharged in proportion to the boom (lower) lever stroke is #IJ1. in pipes 2g, 4+, and 47.55 on the head side opposite to the boom (upper). Second.
Fifth. Sent from the 6th pump 21゜22.25.26,
Nokuirot check valve P12d, P12α, P15d
, P15α, P16d, P16α, BO3°BO2 are opened by pilot pressure, and pilot check valve PI2
d, P15d, and PI6d, and is guided from the pilot check valve f3o3 to the rod side of the boom cylinder 7.

(2) Boom (bottom), arm (extension), travel (left).

(Right) In the case of simultaneous forward operation, the priorities for the actuators of the first to sixth pumps 21 to 26 are stored in the computing unit (microcomputer) as shown in item 113. 26
The IIE amount is distributed to the first pump z+xms pump 25 and the sixth pump 26 as shown in the table.

Specifically, the oil discharged from the second pump 22 is guided to the rod side of the boom cylinder 7 through a pipe line 41 on the rod side and through pilot check valves PI2d, BL)3 that are opened by the boom (lower) signal. The oil from the head side of the boom cylinder 7 passes through the pilot check valve B62.P12α, which is opened by the boom (down signal), and returns to the second pump 22 from the head side pipe line 4°.

The oil discharged from the No. I pump 21 is defined as the forward side when the pressure oil is released from the pipe line 28 on the rod side.
The oil is guided to the left travel motor 1g through the pilot check valve Lt3, which is opened by the left travel forward signal, and the return oil from the left travel motor 1g passes through the pilot check valve L42 and enters the head side pipe. 27 through the second
It is supplied to the pump 22.

Further, the pressure oil from the fifth pump 25 passes through a pipe line 46 on the head side and is opened by the pilot pressure of the arm (extension). Pilot check valve P25C.

The return oil from the rod side is guided to the head side of the arm cylinder 9 through AfA, and the pilot check valve Art is opened by the pilot pressure of the arm (extension).
Pump 2 from the pipe line 47 on the rod side through P25b.
5.

Further, the oil discharged from the sixth pump 26 is supplied to the pipe line 5 on the rod side.
If the time when pressure oil is generated on the 5 side is defined as the forward movement side, the pressure oil is guided to the right movement motor 19 through the head side pipe 54 and through the pilot check valve Pt4, which is opened by the pilot pressure of the right movement forward movement. The return oil from the right travel motor 19 passes through the pilot check valve Ptl and enters the pipe line 5 on the rod side.
4 and is supplied to the sixth pump 26.

During these simultaneous operations, the required amount of return power oil from the head side of the boom cylinder 7 is supplied to the second pump 22 through the pipe line 41 on the rod side, and the surplus is returned to the charge pump circuit from the flow rate adjustment valve F2B. It will be done.

On the other hand, the fifth pump 25 supplies pressure oil to the head side of the arm cylinder 9, and the oil returned from the rod side alone does not ensure the amount of oil necessary to supply to the head side.

(At -C, the excess oil from the head side of the boom cylinder 7 passes through the flow rate adjustment valve F2B and flows through the flow rate adjustment valve F5H.
The water is supplied to the fifth pump 25 through a conduit 47 on the rod side.

In addition, the lack of return oil due to leakage from the left and right travel motors 1g and +9 is also transferred from the charge pump circuit through the flow rate adjustment valves FIB and P6B to the head side pipes 27.
54 to 1st. A sixth pump 21.26 is supplied.

In this way, the flow rate adjustment valve FIH is used to adjust the amount of pump suction oil.
, FIB-F6H, F6B.

Also, the charge pump circuit is connected to each cylinder at 7.9°13.
17 suction safety valves 31.4a, 58.51, and when each cylinder 7.9, 13°17 operates in the direction of natural fall due to gravity, the first. Second. 6th. Oil is supplied to the cylinders 7.9, 13.17 through the suction safety valves 31, 44, 58.51 even if there is a shortage of oil from the fifth pump 21, 22° 26.25. It has become.

During these simultaneous operations, holding pressure is generally maintained on the head side of the boom cylinder 7 due to the weight of the work equipment and the potential energy of the load, and the pressure oil from the head side of the boom cylinder 7 is passed through the pilot check valve PI2α and the head side. is supplied to the second pump 22 through the pipe line 4o. At this time, the second pump 22 operates as a motor and moves the first pump 2 or the second pump 22 via the PTOI gear train.

As a result, the weight of the work equipment and the potential energy of the load can be effectively recovered and used.

(Boom 31 (lower), when operating simultaneously to stop swinging During such simultaneous operations, all pumps 1 to 6 of 21 to 26 operate as motors and try to recover the boom potential energy and swing energy. , In such a case, the engine's braking torque will generally be increased and the engine will overrun.To avoid this, under these conditions,
With respect to the pump tilting angle that is proportional to each lever angle, the pump tilting angle is narrowed down to a rate that does not exceed the allowable engine braking torque. Regarding this carrot and pump control method, for example, by detecting the engine rotation speed, detecting the pump inlet and outlet oil pressure, and detecting the pump servo position, the tilting angle of the pump that is about to exceed the allowable braking torque of the engine is determined by one percentage. , just narrow it down to what you need.

Effects of the Invention The present invention is as described above, and since it is a completely closed circuit, energy can be recovered and reused.Also, since it is a crossover closed circuit, a large-capacity pump is required for each actuator. It is economical because the flow rate is distributed to each actuator of each pump in a crossover circuit, and the pump discharge amount is controlled by a control lever signal, allowing the operator to control the speed as desired and allowing good simultaneous operation of each actuator. can be secured.

[Brief explanation of drawings]

Fig. 1 is a side view of the construction machine, Fig. 2 is an explanatory diagram of the configuration of an embodiment of the present invention, Fig. 3 is an explanatory diagram of the configuration of the swing hydraulic circuit, and Fig. 4 is an explanatory diagram of the configuration of an embodiment of the present invention.
The figure is an explanatory diagram of the configuration of the control circuit. A is boom hydraulic circuit, C is arm hydraulic circuit, -D is bottom dump hydraulic circuit, E is packet hydraulic circuit, B, F are left and right travel hydraulic circuits, 8 is crossover circuit, R is control circuit.

Claims (1)

[Claims] Boom hydraulic circuit A, arm hydraulic circuit C, bottom dump hydraulic circuit D, packet hydraulic circuit E, and left and right travel hydraulic circuits B
, F as one group, and boom hydraulic circuit A, arm hydraulic circuit C, bottom dump hydraulic circuit D, packet hydraulic circuit E, and left and right running hydraulic circuits B and F as a closeover circuit S. By short-circuiting and creating a closed circuit, the swing hydraulic circuits G and H are closed circuits, and the flow rate is distributed to each actuator according to the priority determined in advance by the control lever signal, and the speed of any actuator is adjusted according to the magnitude of the control lever signal. A hydraulic circuit device for construction machinery, characterized in that it is configured to include a control circuit R for controlling.