JP6038509B2 - Pressure compensation valve, hydraulic control valve integrated with the pressure compensation valve, and construction machine equipped with the hydraulic control valve - Google Patents

Description

Hydraulic used in construction machinery operation, relate multiple-hydraulic control valve, and arranged the pressure compensating valve to meter-called a load sensing system, the present invention relates to a hydraulic control device for the flow rate control method.

The flow rate control method , called the load sensing method, is a hydraulic control device that controls multiple actuators with a single pump, and detects the maximum load pressure of multiple actuators so that the pump discharge pressure is a constant higher pressure than the detected pressure. This is a control method. The difference in load pressure to the pump pressure is referred to as load sensing differential pressure. When actuating the plurality of actuator operates in response to the maximum load pressure, switching valve called the pressure compensating valve shown in FIG. 4 is arranged for each actuator, the switching valve, the low load-side actuator Is increased to the maximum load pressure.

JP 2007-321908 A

However, since the must be controlled several actuator 1 pump with load sensing system, control of the pressure complement償弁largely affects the operation of the hydraulic excavator. In extreme loads are different or if low flow control there is a problem with the results in the hydraulic fluid flows to the lower of the load.

The present invention has been made to solve the above-mentioned problems. Compared to the conventional case, the present invention reliably supplies a high load actuator even when there is a difference in load pressure, even when the flow rate is low, without increasing the number of parts. An object of the present invention is to provide a hydraulic device that can improve the operability of a hydraulic excavator because the flow rate can be adjusted.

A hydraulic control device for a construction machine, which is a first invention for achieving the above object, is equipped with a pressure oil supply pump, and controls a multiple hydraulic control valve to which the pressure oil from the pump is supplied. And a hydraulic control device for a construction machine in which a pressure compensation valve is arranged on the meter-in side, opposite to a working chamber in which the highest load pressure of another actuator is introduced to one end of the slidable valve body of the pressure compensation valve A working chamber in which self-pressure is introduced at one end of the valve, a notch for controlling the flow rate outside the valve body as a path for the first hydraulic oil, and a supply passage to the actuator via the notch The valve body internal passage as the second hydraulic oil path, the throttle for reducing the pressure of the hydraulic oil at the entrance of the second hydraulic oil path, and the self-pressure via the throttle branches working chamber inlet and the valve body internal passage, further wherein Internalization passage branches to the supply passage of the highest load pressure introduction port and the actuator F, the highest load pressure introducing passage via a check valve, connected to the highest load pressure passage, the supply passage to the actuator It is characterized by merging with the first route.

A pressure compensation valve arranged in a hydraulic control device for a construction machine, which is a second invention for achieving the above object, is equipped with a pump for supplying pressure oil, and is a multiple type in which the pressure oil from the pump is supplied The pressure compensation valve is arranged on the meter-in side of the hydraulic control device of the construction machine that controls the hydraulic control valve of the machine, and the maximum load pressure of the other actuator is introduced into one end of the slidable valve body of the pressure compensation valve A working chamber in which self-pressure is introduced at the opposite end, a notch called a notch for controlling the flow rate outside the valve body as a path for the first hydraulic oil, and via the notch And a valve body internal passage as a second hydraulic fluid path connected to the supply path to the actuator, and a throttle for reducing the pressure of the hydraulic oil at the entrance of the second hydraulic oil path; The self-pressure working chamber inlet through the throttle Branches valve body internal passage, further, the valve body internal passage is branched into the supply passage of the highest load pressure introduction port and the actuator F, the highest load pressure introducing passage via the check valve, the highest load pressure It connects with a channel | path, The supply channel | path to an actuator joins a 1st path | route, It is characterized by the above-mentioned.

A construction machine equipped with a hydraulic control device according to a third aspect of the invention for achieving the above object is equipped with a pump for supplying pressure oil, and a multiple-type hydraulic control valve to which pressure oil from the pump is supplied. A construction machine that is equipped with a hydraulic control device that controls and has a pressure compensation valve arranged on the meter-in side, in which the highest load pressure of another actuator is introduced into one end of the slidable valve body of the pressure compensation valve A working chamber in which self-pressure is introduced at one end opposite to the chamber, a notch for controlling the flow rate outside the valve body as a path of the first hydraulic oil, and the actuator to the actuator via the notch A valve body internal passage as a second hydraulic oil path, connected to the supply path, a throttle for reducing the pressure of the hydraulic oil at the inlet of the second hydraulic oil path, and via the throttle , Self-pressure working chamber inlet and valve body internal passage And, further, the valve body internal passage is branched into the supply passage of the highest load pressure introduction port and the actuator F, the highest load pressure introducing passage via a check valve, connected to the highest load pressure path, The supply passage to the actuator joins the first path.

According to the present invention, the working chamber in which the highest load pressure of the other actuator is introduced into one end of the valve body of the slidable pressure compensating valve, the working chamber in which self-pressure is introduced into the opposite end, and the first There is a notch called a notch for controlling the flow rate outside the valve body as a hydraulic oil path, and a supply path to the actuator via the notch. Then, a throttle for reducing the pressure of the hydraulic oil is provided at the entrance of the second path, and is connected to the supply path to the actuator via the valve body internal path. Thus, hydraulic oil is supplied to the branched flow actuator and first and second paths, diversion ratio of the first and second paths are determined by the opening. The first path is closed by the movement of the valve body of the pressure compensating valve, boosts the autogenous pressure, the valve body of the pressure compensating valve is the difference in highest load pressure and autogenous pressure, i.e., balanced in a position to become a spring force, considering that the spring force is small compared to the highest load pressure or the autogenous pressure, the highest load pressure that is, the position of the autogenous pressure. A throttle is provided in the second path, and the pressure drops as the flow rate passes. The lowered pressure is introduced into the self-pressure chamber and acts. Therefore, the pressure compensating valve is boosted more first balancing, apparently path at the closing position, it determines a low load pressure actuator to be higher pressure drop. Thus, by arbitrarily adjusting the throttle opening degree, it is possible to adjust the speed of the actuator during the combined operation.

1 shows a schematic configuration of a typical hydraulic excavator as a construction machine to which the present invention is applied. It is a cross-sectional view of a pressure compensation valve according to the present invention and a hydraulic control valve integrated with the pressure compensation valve. It is a cross-sectional view of the pressure compensation valve according to the present invention. It is a cross-sectional view of a conventional pressure compensation valve. 5 is a graph of BM load pressure versus flow rate comparing a pressure compensation valve according to the present invention, a hydraulic control valve integrated with the pressure compensation valve, and a conventional hydraulic control valve.

  FIG. 1 shows a schematic configuration of a typical hydraulic excavator as a construction machine to which the present invention is applied. In FIG. 1, an excavator 10 has an upper swing body 12 mounted on a lower traveling body 30 driven by a hydraulic motor via a swing mechanism 28 so as to be rotatable. The upper swing body 12 is provided with a cab 14 at one front side portion thereof, and a boom 16 is attached to the front center portion so as to be able to be raised and lowered. An arm 20 is attached to the tip of the boom 16 so as to be rotatable up and down, and a bucket 24 is attached to the tip of the arm 20. Reference numeral 26 is a boom hydraulic cylinder, 18 is an arm hydraulic cylinder, and 22 is a bucket hydraulic cylinder. Although not shown in the drawing, a motor and a variable displacement pump driven by the motor are mounted in the upper swing body 12, and a flow rate adjusting mechanism for controlling the rolling angle of the swash plate by a load sensing signal is provided. I have. Further, hydraulic control valves corresponding to the hydraulic motors for the lower traveling body 30 and the upper swing body 12, the hydraulic cylinder 26 for the boom, the hydraulic cylinder 18 for the arm, and the hydraulic cylinder 22 for the bucket, which are hydraulic actuators, respectively. Are stacked and arranged as a multiple valve.

FIG. 2 shows a detailed cross section of the hydraulic control valve CV of the present invention used in the multiple valve of the hydraulic control device. In FIG. 2, one hydraulic actuator 32 in the excavator 10 is connected to cylinder ports PA and PB of the hydraulic control valve CV via lines 32a and 32b. A main spool having a pressure compensation valve 54 arranged on the meter-in side of the hydraulic control valve CV has pressure oil signal input ports a and b at both ends and is slidable in the left-right direction. 36 is provided. Reference numeral 40 denotes a load check portion. A spring 41 is provided in a lower opening formed inside a cap 40a fixed to the valve main body 34, and a check valve 66 having a valve body seat portion at an end portion is provided. It is arranged to urge downward.

Reference numerals 42 and 44 indicate the pressure oil in the pressure oil supply path 58 to the passage 62a or 62b as indicated by arrows A and B when the check valve 66 is raised by the pressure oil from the pressure oil supply path 58. Pressure oil supply path leading to Reference numeral 46 is a pump high-pressure supply passage for supplying high-pressure oil from the pump 45. An adjacent supply passage 48 is formed on the left side at a predetermined interval, and the main spool 36 moves to the right . At this time, as indicated by an arrow C, pressure oil is supplied from the pump high-pressure supply passage 46.

The supply passage 48 is arranged so that the right part of the spool (valve element) 54a of the pressure compensation valve 54 intersects. The right end of the spool 54a of the pressure compensating valve 54 urges the spool 54a is disposed a spring 54d is always in the left. Maximum load pressure on the valve body internal passage 56 in communication with the second aperture 52b are given to the maximum pressure passage 68 provided in the left side of the spool 54a. When this pressure is smaller than the spring force of the spring 54d, the spool 54a is positioned on the left end side as shown. Reference numeral 54 b is a cap fixed to the valve body 34 .

  The supply passage 48 and the pressure oil supply passage 58 are connected by the first route D and the second route E.

  The first path D is connected via a notch 53 that is a notch provided on the side surface of the spool 54 a of the pressure compensation valve 54.

  A working chamber 61 into which the maximum load pressure is introduced is provided at one end on the left side of the paper surface of the spool 54a, and a working chamber 60 on which self pressure acts is provided at the other right side of the paper surface of the spool 54a.

The second path E includes a first throttle 52a that communicates with the valve body internal passage 56 provided along the central axis from the supply passage 48 to the inside of the spool 54a, and a valve body internal passage 56 that communicates with the first throttle 52a. The valve body internal passage 56 and the pressure oil supply passage 58 are connected to each other, and the second throttle 52b and the pressure oil supply passage 58 are joined. The pressure oil supply passage 58 merges with the first route D.

  The pressure on the downstream side of the first throttle 52a is introduced into the working chamber 60 where the self pressure acts. The pressure in the valve body internal passage 56 opens the check valve 64 connected to the valve body internal passage 56 and is connected to the maximum pressure passage 68 via the connection passage 70.

Next, the operation will be described with reference to FIG. FIG. 3 is a diagram in which the spool 54a has moved to the right side of the drawing due to the maximum load pressure applied from another actuator. The hydraulic oil in the first path D has a small opening in the notch 53 and the pressure oil supply path 58 due to the movement of the pressure compensation valve 34. For this reason, the hydraulic fluid in the first path D is throttled and boosted. Further, as the first path D is throttled, the amount of hydraulic oil in the second path E increases on the contrary. The amount of hydraulic oil in the second path E is affected by the pressure drop by passing through the first throttle 52a, and the self-pressure is lowered by the amount of the pressure drop. Also, the hydraulic fluid of the first path D passes through the valve body internal passage 56, is discharged to the pressure oil supply passage 58 to the actuator, and merges with the first path D. In a conventional pressure compensation valve, if the spring force is considered to be very small,

(K: constant, PLS: maximum load pressure , Q: passing flow rate). In the present invention, if the overall flow rate is Q , the first flow rate is q1, the second flow rate is q2, and the throttle opening is A0,

(K: constant, PLS: maximum load pressure) Therefore, from this equation, (conventional opening degree)> (opening degree of the present invention) is always established, and the opening degree of the first path D is made smaller and the pressure is increased higher. You can see that Therefore, along with it can be difficult to flow more pressurized hydraulic fluid to lower actuator load, by adjusting the opening degree of the first throttle 52a, it is possible to adjust the flow rate arbitrarily. Further , the hydraulic oil is discharged from the second path E through the connection passage 70. However , it is generally known that the discharge in the shape of the hole is less affected by the fluid force. It becomes a pressure compensation valve with good controllability.

  According to FIG. 5, when comparing the pressure compensation valve according to the present invention, a hydraulic control valve integrated with the pressure compensation valve, and a conventional hydraulic control valve in a graph of BM load pressure versus flow rate, the conventional hydraulic control valve is compared. However, it is shown that the required flow rate cannot be secured at a pressure higher than 22 MPa, whereas the hydraulic control valve according to the present invention can secure a flow rate up to 30 MPa, as shown by B in FIG. . In the conventional example, as shown by A in FIG. 5, it can be seen that the flow rate disappears as the BM load pressure increases.

  Although the preferred embodiments of the present invention have been described with reference to the drawings, those skilled in the art can naturally make various modifications based on the above drawings and descriptions.

DESCRIPTION OF SYMBOLS 10 Hydraulic excavator 12 Upper turning body 14 Cab 16 Boom 18 Arm hydraulic cylinder 20 Arm 22 Bucket hydraulic cylinder 24 Bucket 26 Boom hydraulic cylinder 28 Turning mechanism 30 Lower traveling body 32 Hydraulic actuators 32a and 32b Line 34 Pressure compensation Valve 36 Main spool 40 Reference numeral 40a Cap 41 Spring 42, 44 Pressure oil supply path 45 Pump 46 Pump high pressure supply path 48 Supply path 52a First throttle 52b Second throttle 53 Notch 54 Pressure compensation valve 54a Spool 54b Cap 54d Spring 56 Valve Body internal passage 58 Pressure oil supply passage 60 Working chamber 61 Working chamber 62a, 62b Passage 64 Check valve 66 Check valve 68 Maximum pressure passage 70 Connection passage A, B View C View CV Hydraulic control valve D First route E Second path PA, PB Cylinder port a b pressure oil signal input port

Claims (4)

A hydraulic control device for a construction machine equipped with a pressure oil supply pump, which controls a multiple-type hydraulic control valve to which pressure oil is supplied from the pump, and has a pressure compensation valve arranged on the meter-in side,
A first working chamber in which the highest load pressure of another actuator is introduced into one end of the slidable pressure compensating valve;
A second working chamber in which self-pressure is introduced at the opposite end;
A spring for urging the valve body toward the first working chamber;
Notches for controlling the flow rate to the valve body outside of the first route,
A valve body internal passage of the second route,
At the entrance of the second route, to communicate with each other and the valve body internal passage and supply passage, and a first aperture for causing pressure drop hydraulic oil,
A second throttle for communicating the valve body internal passage and the pressure oil supply passage to the actuator at the outlet of the second passage;
The hydraulic oil control device for a construction machine , wherein the hydraulic oil in the second path passes through the valve body internal path, is discharged to the pressure oil supply path, and merges with the first path. The hydraulic control device for a construction machine according to claim 1, wherein the first working chamber is connected to a valve body internal passage through a check valve. A pressure compensation valve disposed on the meter-in side of a hydraulic control device of a construction machine that is equipped with a pressure oil supply pump and controls a multiple-type hydraulic control valve to which pressure oil from the pump is supplied,
A first working chamber in which the highest load pressure of another actuator is introduced into one end of the slidable pressure compensating valve;
A second working chamber in which self-pressure is introduced at the opposite end;
A spring for urging the valve body toward the first working chamber;
When notch called notch for controlling the flow rate in the valve body outside of the first route,
A valve body internal passage of the second route,
At the entrance of the second route, to communicate with each other and the valve body internal passage and supply passage, and a first aperture for causing pressure drop hydraulic oil,
A second throttle that communicates the valve body internal passage and the pressure oil supply passage to the actuator at the outlet of the second passage;
The hydraulic oil in the second path passes through the valve body internal path, is discharged to the pressure oil supply path, and merges with the first path. Compensation valve. A construction machine equipped with a hydraulic control device equipped with a pressure oil supply pump, which controls a multiple-type hydraulic control valve to which pressure oil from the pump is supplied and which has a pressure compensation valve arranged on the meter-in side. ,
A first working chamber in which the highest load pressure of another actuator is introduced into one end of the slidable pressure compensating valve;
A second working chamber in which self-pressure is introduced at the opposite end;
A spring for urging the valve body toward the first working chamber;
When notches for controlling the flow rate to the valve body outside of the first route,
A valve body internal passage of the second route,
At the entrance of the second route, to communicate with each other and the valve body internal passage and supply passage, and a first aperture for causing pressure drop hydraulic oil,
A construction machine equipped with a pressure oil control device , wherein the hydraulic oil in the second path passes through the valve body internal path, is discharged to the pressure oil supply path, and merges with the first path.

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