JPH1089308A - Variable priority device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a varible priority device recognizing pilot pressure by set pressure by which a high pressure side control valve for supplying hydraulic operating fluid to a work device for which high load is requested can be made to operate a high load work device and supplying control pressure to a logic valve so that a low load work device may not be driven till pressure becomes the set pressure. SOLUTION: In a variable priority device provided with a logic valve LV which is installed in the pump passage 9A of a low pressure side control valve 5 and interrupts the pump passage 9A in proportion to a prescribed signal, pilot pressure by which a high load work device located at a hydraulic line can be operated is recognized and a sequence valve 25 supplying an output signal to control area of the orifice of the logic valve LV by feedbacking hydraulic operating fluid which is pumped from a pump is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an excavator for driving a plurality of working devices with one pour.
The present invention relates to a variable priority device used for a hydraulic line having heavy equipment such as a tor (e.g., tor), and in particular, recognizes a pilot pressure capable of operating a high-load working device, and feeds back an operating oil pressure pumped from a pump. b
ack) logic valve (logic valve)
e) controlling the area of the orifice so as to minimize the time delay during which the high-load working device is operated after the operation of the low-load working device and to operate the low-pressure working device and the high-pressure working device simultaneously; Sequence valve (se
This is open to a variable priority device provided with a "queue value".

[0002]

2. Description of the Related Art Generally, "priority" applied to heavy equipment
Controls the operation of at least two actuators combined with the oil discharged from a single pump so as to receive a relatively higher flow rate than an actuator that requires a high load. That is. For example, in the case of an excavator, turning priority is applied to an arm, and boom priority is applied to a bucket. The reason for applying the priority in this way is that, in general, the required flow rate during turning is greater than the required flow rate during arm operation, and the required flow rate during boom operation is greater than the required flow rate during bucket operation. is there. Thus, the operation of the equipment can be smoothly performed by supplying a difference in flow rate so that the high-load working device is operated in proportion to the moving speed of the low-load working device.

[0003] One method for applying such a priority device to a hydraulic line for driving the boom and bucket of an excavator is to use a fixing orifice in a hydraulic supply line for a bucket requiring a low load. When the bucket operates independently when using the orifice for
As a result, there is a problem in that the operating pressure discharged from the pump cannot be sufficiently used for a low-load working device due to a pressure loss.

[0004] In various bills for re-election, a sequence variable control device has been developed in which the supply flow rate on the low load side is automatically determined by the load pressure acting on each of the high load operation device and the low load operation device. .

That is, such a variable priority device of the excavator is shown in FIG. One pump 1
A plurality of actuators, ie, a boom cylinder 3 and a bucket cylinder 6 are driven via an oil passage 1A through the oil passage 1A. A control valve (hereinafter abbreviated as boom) 2 and a bucket driving control valve (hereinafter abbreviated as boom)
5 is abbreviated as “BKT”. BKT5
The piston 7, which is movably positioned up and down, is provided in the hydraulic oil supply passage 9A.
k: 9), and a logic valve in which a piston pressure chamber 8 formed in the upper part of the piston 7 is provided. The opening area of the orifice 10 formed between the lower part of the load check 9 and the supply passage 9A is changed by the pressure change of the piston pressure chamber. The sequence valve 4 is connected to the piston pressure chamber 8 so as to supply pressure oil to the piston pressure chamber 8 formed by the output side oil passage 12.

The output port 12 of the sequence valve 4
As shown in FIG. 2, A is connected to an output-side oil passage 12 that communicates with the piston pressure chamber 8, and a drain port 18A is connected to a return oil passage 18. Similarly,
The pump port 11A is an input-side oil passage 1 branched from the oil passage 1A.
Connected to one. A sleeve is inserted inside the housing 40, and the pilot piston 17 is inserted movably to the left and right by the pilot pressure of the pilot oil passage 23 that branches off the oil passage that supplies the pilot pressure Pi to the boom control valve 2. There is.
The other end of the spool 13 which is in contact with one end of the pilot piston 17 is inserted into the sleeve 14 so as to be supported by the return 15.
Is formed. By moving the spool 13, the pump port 11 </ b> A communicates with the output port 12 </ b> A, and the end of the cylindrical inner chamber 32 formed at the center of the spool 13 so as to communicate with the internal passage 30 is connected to the housing 40. The other end is interlocked with the protruding portion 16 protruding.

In this state, when performing a combined operation of the boom UP and the bucket 1N during excavation, the pilot pressure Pi for driving the boom 2 is controlled by the pilot valve of the sequence valve 4 via the oil passage 23. Acting on the piston 17, the pilot piston 17 is moved rightward in the drawing of FIG. As a result, the spool 13 interlocked with the pilot piston 17 causes the return spring 15
Of the internal passage 30
As a result, the pump port 11A communicates with the output port 12A. Therefore, the output side port 12A
, The pressure of the piston pressure chamber 8 increases, and the piston 7 and the load check 9 face downward. Therefore, the opening area of the orifice 10 is reduced, and the working flow rate flowing into the bucket 5 via the hydraulic pump 1 is reduced. As a result, the working flow rate for driving the boom is increased.

On the other hand, the X axis in FIG. 6 shows the pilot pressure Pi supplied to the sequence pulp 4, and the Y axis shows the pressure acting on the output port 12A of the sequence valve, that is,
4 shows the hydraulic pressure of the piston pressure chamber 8. As shown,
When the pilot pressure Pi first rises, the spool 13 turns to the right, so that the internal passage 30 connected to the output port 12A communicates with the pump port 11A, and the pressure in the output oil passage 12 becomes linear. Will increase.

Further, since the internal passage 30 is communicated with the cylindrical inner chamber 32, the pump port 11A is connected to the cylindrical inner chamber 32.
Operating pressure is formed.

In this state, the parallel state of the forces in the sequence halves 4 is such that the sectional area of the pilot piston 17 is A1, the sectional area of the cylindrical inner chamber 32 is A2, the pilot pressure is Pi, and the pressure of the cylindrical inner chamber 32 is P1, and turn spring 1
Assuming that the elastic force of No. 5 is Fs1, the formula of PiA1 = P1A2 + Fs1 is established. Here, the left type of the equal sign is the force for pushing the spool 13 to the right, and the right type of the equal sign is the spool 1
3 shows the force to push left. Since Fs1 is a constant, P1
Is increased in a state where is kept constant, the spool 13 is proportionally moved to the right side, and the open area of the pump port 11A linearly increases. Eventually, the operating pressure of the output side boat 12A shows a state as shown in the diagram A of FIG. 6, where Pil in the diagram A is the pilot pressure at which the bucket is initially operated, and Pi2 is the pilot pressure at which the boom is initially operated. Indicates pressure.

[0011]

However, when the boom and the bucket are operated in combination, the boom UP operation is performed by a difference between the operating pressure Pi2 for operating the boom which is relatively larger than the operating pressure Pi1 for operating the bucket. A pilot pressure section (Pi1 to Pi2) in which only the bucket IN operation is performed without being performed is generated. After all, the working device was driven sequentially from the pilot pressure in this section.
Therefore, there has been a problem that the work function intended by the creator is not performed correctly, and that the driving sensation is deteriorated and the work efficiency is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to recognize a pilot pressure at a set pressure at which a high-load working device can be operated by a high-pressure side control valve for supplying hydraulic oil to a working device requiring a high load. An object of the present invention is to provide a variable priority device that supplies a control pressure to a logic valve so that a low-load working device is not driven until a set pressure is reached.

[0013] Another object of the present invention is to provide a feedback control of a hydraulic pressure pumped from a pump.
k) receiving and controlling the area of the orifice so as to minimize the time delay in which the high-load work device is activated after the low-load work device is activated, so that the low-pressure work device and the high-pressure work device are operated simultaneously. Another object of the present invention is to provide a variable priority device that improves the work efficiency of equipment.

An object of the present invention described above is to install a pump in a pump passage of a low-pressure side control valve located in a hydraulic line for driving a plurality of working devices with one pump, and in proportion to a predetermined signal. A variable priority device provided with a logic valve for shutting off the pump passage recognizes a pilot pressure capable of operating a high-load working device located in the hydraulic line and feeds back an operating oil pressure pumped from the pump. (Feed
back) Logic valve (logicvalv)
This is achieved by providing a variable priority device characterized by being provided with a sequence valve for providing an output signal for controlling the area of the orifice in e).

[0015]

SUMMARY OF THE INVENTION Desirable feature 1 of the present invention
According to the above, the sequence valve has a pump passage for supplying hydraulic oil discharged from the pump, an output passage connected to the logic valve, a number of drain passages, and a through hole formed in the center. A housing which is inserted into one side of the through hole so as to be perturbable, and one side of which is communicated with a pilot oil passage of the high pressure side control valve so that a pilot pressure for driving the high pressure side control valve is applied; A pilot piston having a hollow portion formed therein; a piston having a load fixed to one end of the hollow portion and being perturbably inserted into one end of the hollow portion; a perturbable other end of the hollow portion A guard inserted at the other end and projected outside the piston; the hollow portion for recognizing a pilot pressure for driving the high-load working device Recognition means are positioned inside; Yes fixed inserted into the other side of the through hole, the pump passage,
A sleeve formed with a pump port and an output port and a drain port which are respectively connected to the output side passage and the drain passage; and a perturbation inserted inside the sleeve, one end of which is connected to a guard of the pilot piston,
The other end is a spool elastically supported by a return spring; the pump port is formed at one end of the spool and is connected to the drain port in proportion to the movement of the spool from an initial state of communicating the pump port and the drain port of the sleeve. An internal passage for blocking communication with the output side port to increase the communication area with the output side port; a plug fixed to the other end of the bill on the housing and supporting the other end of the return spring; It is provided with feedback means for changing the spool to an initial state in opposition.

According to a preferred feature 2 of the present invention, the recognizing means is provided between the piston and the guard so as to maintain the piston at one side in a stroke ending state, and the recognition means at the other side. An elastic member is provided to elastically bios so as to maintain the stroke ending state and maintain a constant interval between the other end of the load and one end of the guard.

In a preferred feature 3 of the present invention, the feedback means includes a cylindrical inner chamber formed inside the spool so as to communicate with the internal passage; It is provided with a pushed-in protruding portion of the inner chamber.

According to a desirable feature 4 of the present invention, the elastic force of the elastic member limits the opening area of the low pressure side pump passage so that the low load working device and the high load working device are simultaneously operated. The sequence pilot pressure when pressure is generated at the sequence output port for driving the logic valve is set to be the same as the force acting on the cross-sectional area of the pilot piston.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 of the accompanying drawings is a device diagram showing a variable priority device according to an embodiment of the present invention, and FIG.
It is an enlarged view of a sequence valve in FIG.

5 (a), 5 (b), 5 (c) and 5 (d) are operating state diagrams of the sequence valve, and FIG. 6 shows an output side of the sequence valve when the pilot pressure acting on the sequence valve is increased. It is a graph which shows the change of hydraulic pressure.

As shown in FIG. 3, the variable priority device according to this embodiment includes a low-load work device 6 and a high-load work device in a hydraulic line in which a plurality of work devices 3, 6 are driven by one hydraulic pump 1. It is separated from the device 3. This variable priority device is applied to heavy equipment such as an excavator equipped with a logic valve LV installed in the pump passage 9A of the low pressure side control valve 6 so as to shut off the pump passage 9A in proportion to a predetermined signal. You.

The low load actuator 6 and the high load actuator 3 driven by the hydraulic pump 1, the low pressure and high pressure control valve 2 for switching the hydraulic oil supplied to these actuators by the pilot signal Pi, to the low pressure side pump passage 9 A. In the present embodiment, the same reference numerals are given to the installed logic valve LV and components substantially the same as those of the related art described with reference to FIGS. 1 and 2, and a detailed description thereof will be omitted.

The variable priority device according to the present embodiment recognizes a pilot pressure (Pi1 in diagram B in FIG. 6) at which the high-pressure side control valve 2 can operate the high-pressure side working device 3, and is pumped from the pump 1. Sequence valve 2 that receives the feedback of the operating hydraulic pressure P1 and supplies an output signal for controlling the area of the orifice 10 of a logic valve
5 is included.

As shown in FIG. 4, the sequence valve 25 includes a pump passage 11A through which hydraulic oil discharged from the pump 1 is supplied, and the logic valve LV.
An output side passage connected to the piston pressure chamber 8, a plurality of drain passages 18A are formed, a housing 40 having a through hole formed in the center, and a perturbation inserted into one side of the through hole 24. One side is connected to a pilot oil passage 23 branched from a pilot oil passage of the high-pressure control valve so that a pilot pressure Pl for driving the high-pressure control valve 2 acts thereon.
, A pilot piston 19 having a load 27 fixed to one end of the pilot piston 19, which is inserted into one end of the other end 26 of the hollow portion so as to be perturbable.
2. Perturbably inserted into the other end of the hollow part,
A guard 20 having the other end protruding outside the piston, a recognition means positioned inside the hollow portion 26 for recognizing a pilot pressure for driving the high-load working device, A sleeve 14, which is fixedly inserted and has a pump port 11A, an output port 12A, and a drain port 18A which are respectively connected to the pump passage 11, the output side passage 12, and the drain passage 18, and can swing inside the sleeve. One end is connected to the guard of the pilot piston 19, and the other end is a spool 1 elastically supported by a return spring 15.
3. The pump port 11A is connected to the drain port 18A in proportion to the movement of the spool 13 from an initial state formed at one end of the spool 13 and communicating the pump port 11A of the sleeve 14 with the drain port 18A.
An internal passage 30 for blocking communication with the output port 12A and increasing the area of communication with the output port 12A, and a plug 28 fixed to the other end of the through hole 24 of the housing 40 and supporting the other end of the return spring 15 , And feedback means for converting the spool 13 to the initial state against the pilot pressure Pi.

The above-described piston 22 can move inside the through hole 24 within the movement stroke range of the maximum Sl, and
0 can move to the inside of the hollow portion 26 within the movement stroke range of the maximum S2.

The above-mentioned recognition means is installed between the piston 22 and the guard 20 so as to maintain the piston 22 on one side in the stroke ending state, and maintains the guard 20 on the other side in the stroke ending state. As described above, the elastic member 21 is provided so as to maintain the distance between the other end of the load 27 and one end of the guard 20 at a constant interval by causing the elastic member to vibrate.

The elastic force of the elastic member 21 restricts the opening area of the supply passage 9A of the low-pressure side control valve 5 to which the hydraulic oil discharged from the hydraulic pump 1 is supplied, and the low-load working device 6 and the high-pressure side When a pressure is applied to the output port 12A of the sequence valve 25 for driving the logic valve LV so that the working device 5 is simultaneously operated, the driving force F1 due to the pilot pressure Pi acting on the cross-sectional area of the pilot piston is generated. Is set the same as

The elastic force of the elastic member 21 is set to be greater than the elastic force of the return spring 15 and when the pilot pressure Pi acts through the pilot oil passage 23, the return spring 15 is first contracted and the spool 13 Is operated to be moved.

The above-mentioned feedback means includes a cylindrical inner chamber 32 formed inside the spool 13 so as to communicate with the inner passage 30, and one end protruding from the plug 28 and having one end. Is provided.

The operation of the embodiment constructed as described above will be described below.

In order to clarify the operation of this embodiment, the state in which the pressure of the output port 12A is changed by increasing the pilot pressure Pi acting on the sequence valve 25 is divided into the following three stages. Is done. The elastic force FS2 of the elastic member 21 of the pilot piston 19, the pressure P1 acting on the cylindrical inner chamber 32 of the spool 13, and the force due to the elastic force FS1 of the return spring 15 (hereinafter, referred to as the elastic force FS1).
A first stage in a state parallel to the “repulsive force (Fr)”, a driving force F2 by the pilot pressure Pi acting on the piston 22 of the pilot piston 19, and a second stage in a state parallel to the repulsive force Fr. When the driving force F2 becomes larger than the repulsion force Fr, the third stage for obtaining the parallel state again.
These steps are sequentially performed.

First, a state in which the process proceeds from the initial state to the first stage will be described. As shown in FIG.
In an initial state, the spool 13 is in a stroke ending state to the left by the return spring 15, and one end of the spool 13 pushes the guard 20 to the left, and the pilot piston 19 is in a stroke ending state to the left. At this time, the spool 13 connects the pump port (11A) of the sleeve 14 to the drain port 18A.
The state has been switched to communicate with the.

In such a state, the hydraulic pressure, that is, the pilot pressure P1 for driving the high-pressure side control valve 2 is supplied to the pilot oil passage 23, and the pilot piston 19
Is greater than the elastic force FS1 of the return spring 15, which is the repulsive force Fr, by applying the cross-sectional area A1 and the pilot pressure Pi.
Then, the spool 13 moves to the right within the range of the stroke Sl (see FIG. 2B).

At this time, since the elastic force FSl of the elastic member 21 is larger than the elastic force FS2 of the return spring 15,
The elastic member 21 is not contracted. If the movement of the spool 13 causes the pump 11A to close the open state of the drain port 18A and communicate with the internal passage 30 communicating with the output port 12A of the spool 13, the pump 11A is communicated with the internal passage 30. Pump port 11 in cylindrical inner chamber 32
A pump pressure Pl of A will act. At this time, the repulsive force Fr acting on the spool 13 is the sum of the cross-sectional area A2 of the cylindrical inner chamber 32, the force F2 generated by applying the pump pressure Pl, and the force FS2 of the return spring. If it is larger than the elastic force FSl of the elastic member 21,
The spool 13 pushes the guard 20 and moves to the left again within the movement distance S2 where the guard 20 comes into contact with the load 27 (see FIG. 2C). In such a state, it is assumed that the pilot pressure P1 increases and the driving force Fl is larger than the elastic force FS1 of the elastic member 21, and the driving force (F
If l) is smaller than the elastic force FSl, the pilot piston 19 is directed to the left.

After all, when the elastic member 21 is contracted in this way and the spool 13 is directed to the left, the parallel state of the force is expressed by a mathematical formula: FS1 = FS2 + P1A2, and the precondition is FS1 <PiA1. Therefore, in equation 2, the variable is P1, and the operating pressure discharged from the pump and P1 are proportional to the opening area of the pump port 11A and the internal passage 30, so that if the pump discharge pressure is constant, In the equation, the moving position of the spool 13 having the opening area of the internal passage 30 is determined so as to maintain the same value as the left equation. In such a state, the larger the discharge pressure of the pump 1, the larger the FS2 + P1A2> FS1 And the spool is turned to the left so as to minimize the opening area. The guard 20 is in the state shown in FIG.
(B) The state is omitted and the state is switched to the state shown in FIG. 5 (c). Eventually, the time delay in which the high-pressure side working device is activated after the low-pressure side working device is activated is minimized and the low-pressure side operation is performed. The device and the high-side working device are operated simultaneously. At this time, if the elastic force FSl of the elastic member 21 is set to be the same as the pilot pressure for initially driving the high-load working device, the pressure diagram of the output port 12A at Pi1 as shown in the diagram B of FIG. That is, it rises up to the set elastic force FSl of the elastic member 21 in parallel with the Y axis.

Next, the state where the process proceeds from the first stage to the second stage will be described. When the pilot pressure continuously increases, the driving force (F1) has the same value as the elastic force of the elastic member 21. In the state, the pilot Pi is the area A of the piston 22.
In a state in which the driving force F2 acting on No. 3 has the same value as the repulsion force Fr, Pi1 in the diagram B of FIG.
It has two sections.

That is, the pilot pressure having PiA3 = (P1A2 + FS2) is Pi2. In such a state, the spool 13 does not move but simply stops.

Finally, when the state progressing from the second stage to the third stage is described above, the pilot pressure Pi continuously increases and wins the repulsive force Fr which is the right-hand side expression of the equal sign in the equation (3). At this time, the piston 22 is
The inner wall of the hollow portion 26 inside slides and slides to the right, whereby the guard 20 in contact with the load 27 moves within the range of the movement stroke S2, so that the spool 13 moves and, eventually, the pump port 11A and the output port. As the communication area of 12A increases, the pressure of the output side port 12A increases. Also, if the pressure of the output port 12A increases, the repulsion force Fr will increase. If the repulsion force Fr exceeds the driving force F2, the spool 13 will turn to the left again. Therefore,
The spool 13 continuously moves by searching for a follow-up point at which the driving force F2 and the repulsion force Fr become the same, so that the spool 13 eventually reaches the state of FIG. 5D in the state of FIG. , The gart 20 has the stroke S2) The pilot pressure Pi, which is a variable value in this state, and the output port 12
The movement position of the spool 13 is automatically converted by receiving the pump discharge pressure P1 of A as feedback.

As described above, according to the variable priority device of the present invention, the pilot pressure is recognized at the set pressure at which the high-load control valve can operate the high-load working device, and the low pressure is set to the set pressure. A control pressure is supplied to the logic valve so that the side working device is not driven, and a hydraulic pressure pumped by the pump receives a feedback (feedback) to receive a logic halve (log).
controlling the area of the orifice of the ic valve so as to minimize the time delay of the operation of the high-side working device after the operation of the low-side working device so that the low-side working device and the high-side working device are simultaneously operated. This has the effect of improving the work efficiency of the equipment.

[0040]

[Brief description of the drawings]

FIG. 1 is a device diagram showing a conventional variable priority device.

FIG. 2 is an enlarged view of the sequence valve of FIG.

FIG. 3 is a schematic view illustrating a variable priority device according to an embodiment of the present invention;

FIG. 4 is an enlarged view of a sequence valve in FIG.

5 (a), (b), (c) and (d) are operation state diagrams of the sequence valve of FIG. 4;

FIG. 6 is a graph showing a change in an output-side hydraulic pressure of a sequence valve when a pilot pressure acting on a sequence valve increases.

[Explanation of symbols]

 5 control valve 13 spool 19 pilot piston 20 guard 22 piston

Claims (5)

[Claims] 1. A pump installed in a pump passage of a low pressure side control valve located in a hydraulic line for driving a plurality of working devices with one pump, and shuts off the pump passage in proportion to a predetermined signal. A variable priority device provided with a logic valve; recognizes a pilot pressure capable of operating a high-load working device located in the hydraulic line, and receives a feedback (feedback) of an operating hydraulic pressure pumped from the pump. A variable priority device comprising a sequence valve for supplying an output signal for controlling an area of an orifice of the logic valve. 2. The sequence valve has a pump passage through which hydraulic oil discharged from the pump is supplied, an output passage connected to the logic valve, and a plurality of drain passages. A housing formed with a perturbation in one side of the through hole, one side of which is communicated with a pilot oil passage of the high pressure side control valve so that a pilot pressure for driving the high pressure side control valve is applied. A pilot piston having a hollow portion formed therein, a piston having a load fixed to one end of the hollow portion and being perturbably inserted into one end portion of the hollow portion; A gart that is inserted so as to be perturbable and has the other end protruding outside the piston; the hollow for recognizing a pilot pressure for driving the high-load working device Recognition means located inside the portion; a pump port, an output port, and a drain port, which are fixedly inserted into the other side of the through hole and communicate with the pump passage, the output passage, and the drain passage, respectively; A sleeve which is perturbably inserted into the sleeve, one end of which is connected to a guard of the pilot piston, and the other end of which is resiliently supported by a return spring; and which is formed at one end of the spool. An internal portion for increasing the area of communication with the output side port by blocking the pump port from communicating with the drain port in proportion to the movement of the spool from the initial state in which the pump port and the drain port of the sleeve communicate with each other. aisle;
A plug fixed to the other end of the through hole of the housing and supporting the other end of the return spring; and feedback means for converting the spool to an initial state against the pilot pressure. The variable priority device according to claim 1, wherein 3. The recognizing means is provided between the piston and a guard so as to maintain the piston on one side in a stroke ending state and on the other side in maintaining the stroke ending state on the other side. 3. The variable priority device according to claim 2, further comprising: an elastic member that is elastically biased to maintain a constant distance between the other end of the load and one end of the guard. 4. The feed hack means includes: a cylindrical inner chamber formed inside the spool so as to communicate with the internal passage; and one end of the cylindrical inner chamber protruding from the plug and being inserted into the cylindrical inner chamber. The variable priority device according to claim 2, wherein the variable priority device is provided with a projected portion. 5. The elastic force of the elastic member limits the opening area of the low-pressure side pump passage and drives the logic valve so that the low-load working device and the high-load working device are simultaneously operated. 4. The variable priority device according to claim 3, wherein the sequence pilot pressure when a pressure is generated in the sequence output port is set to be equal to a force acting on a cross-sectional area of the pilot piston.