JPS6188008A - Hydraulic control device - Google Patents

Abstract

PURPOSE:To eliminate loss in feeding other actuators by providing a large piston and a small piston on a control valve, and adjusting the opening of a load check valve by means of pilot pressure for shifting said control valve. CONSTITUTION:A large piston 19 and a small piston 18 are provided on a control valve C2, 2 and an operating pressure for an actuator 5 is made act on the small piston 18 while a pilot pressure for shifting a control valve C1 is made act on the large piston 19. And, the opening of a load check valve R can be adjusted in accordance with the forces which act on the large piston 19 and on the small piston 18. Thereby, even if an actuator M connected to the control valve C1 has stopped due to the action of external force, the control of the opening of the load check valve R is not affected in the least, eliminating loss in feeding actuators.

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention provides a hydraulic control device used when actuators with different load pressures are operated simultaneously and it is necessary to drive one of them preferentially.・Regarding.

(Prior Art) The conventional device shown in FIG. 2 is a control device according to Japanese Patent Application Laid-Open No. 58-113 [105], which was filed by the present applicant.

In this conventional control device, for the pump P.

A swing motor M and an arm sill S are connected in parallel, and control valves C and C2 are connected upstream of these actuators.

The control valve C2 that controls the arm cylinder S has a spool 2 built into its main body l, and by switching the spool 2 to either the left or right, the supply passage 3 is connected to either boat A or B. However, the other boat B or A communicates with the tank passage 4.

Furthermore, the supply passage 3 is communicated with the pump P via a load check valve 5 and a parallel passage 6.

Further, a piston 7 is provided above the load check valve 5.
However, the working pressure of the swing motor M acts on the pressure chamber 8 above the piston 7, and the working pressure of the supply passage 3, that is, the arm cylinder S acts on the pressure chamber 9 below. I have to.

The piston 7 moves depending on the magnitude of the pressure within the pressure chamber 8.9, and the lift amount of the load check valve 5 is controlled by the movement position of the piston 7.

That is, when the operating pressure of the swing motor M is high, the piston 7 is held in the lower position due to the pressure action, so that the lift amount of the load check valve 5 is also reduced. In this state, when the load check valve is raised, the parallel passage 6 and the supply passage 3 communicate with each other through the throttle hole 5b formed in the poppet portion 5a.

When the swing motor M is driven in this way and its working pressure is high, a throttling resistance is applied to the flow supplied to the arm cylinder S, so that the hydraulic fluid discharged from the pump P is transferred to the arm cylinder SS. Even if the operating pressure is low, it is preferentially supplied to the swing motor.

On the other hand, when the operating pressure of the arm cylinder S increases, the piston 7 maintains the upper position, so the load check valve 5
The amount of lift increases. When the load check valve 5 rises in this state, the parallel passage 6 and the supply passage 3 communicate with each other via the notch 5C formed in the poppet portion 5a, so that the supply passage for the arm cylinder S becomes large and sufficient Supply flow rate is ensured.

In addition, the symbol in the figure! 0 is a neutral flow path formed in the main body,
This is for passing the oil discharged from the pump P when the spool 2 is in the neutral position.

(Problems to be Solved by the Invention) In the conventional device as described above, for example, when the swing motor is stopped by an external force, the supply pressure increases, so the piston 7 maintains the lower position. It remains as it is.

Therefore, for the supply flow rate to the arm cylinder S,
Since the throttle resistance provided by the throttle hole 5b remains, there is a drawback that the supply loss to the arm cylinder S becomes large.

Furthermore, since the supply pressure of the swing motor M is used as a pilot pressure to act on the piston 7, the pilot piping is set at a high pressure, which has the drawback of being less economical.

In this invention, even if the seven actuators such as the swing motor are stopped due to the influence of an external force, the other seven actuators such as the arm cylinder etc.
The present invention aims to provide a control device in which, when the operating pressure of a cutter increases, a load check valve opens wide in response to the increase in pressure, thereby preventing loss of supply to the other seven cutter.

Another object of the present invention is to provide a control device that uses a pilot pressure unrelated to the operating pressure of a swing motor, etc., and does not require high pressure settings for pilot piping.

(Means for Solving the Problems) In order to achieve the above object, the present invention operates a plurality of seven actuators with one pump, and includes a control valve corresponding to each of these seven actuators,
In addition, these control valves are connected on two sides by connecting the neutral flow path in tandem, and in parallel through a parallel path, and can be opened by applying pilot pressure to the load check valve installed in a specific control valve. In a hydraulic control device configured to adjust the pressure and drive actuators connected to other control valves preferentially over the actuator connected to the control valve, the pressure receiving area is A large piston and a small piston with different values are provided either integrally or separately, and the small piston receives the operating pressure of the actuator connected to the control valve, and the large piston receives the pilot pressure for switching the control valve. The load check valve is configured to act on the load check valve and adjust the opening degree of the load check valve according to the acting force of the large piston and the small piston.

(Action of the present invention) This invention has a large piston and a small piston, so
Even if the operating pressure of the actuator connected to the control valve is applied to the small piston, even if a pilot pressure unrelated to the actuator's operating pressure is applied to the large piston, the opening degree of the load check valve can be freely controlled. It can be adjusted to

(Effects of the present invention) As described above, in this invention, the opening degree of the load check valve is adjusted by the pilot pressure for switching the control valve, so that the actuator connected to the control valve is stopped by external force. Even if this happens, the opening degree control of the load check valve will not be affected in any way.

Further, since the opening degree of the load check valve is adjusted using the pilot pressure for switching the control valve, the pilot piping does not need to be set at a high pressure as in the past.

(Embodiment of the present invention) Fig. 1 shows an embodiment of the present invention, in which a swing motor M and an arm cylinder S are connected in parallel to a pump P, and furthermore, on the upstream side of both actuators, The control valves C1 and C2 are connected, which is the same as in the conventional case.

The load check valve R provided in the parallel passage 6 is configured as follows, unlike the conventional one.

In other words, this load check valve R has a large
The large poppet 11 has its cylindrical portion 11a slidably inserted into the pressure chamber 13, and its poppet portion 11b opens and closes the seat portion 14 of the parallel passage 6.

Further, the small poppet 12 is slidably inserted into the cylindrical portion 11a of the large poppet 11, and the pressure chamber 13
A spring 16 is interposed between the spring receiving plate 15 and the spring receiving plate 15 provided on the holder. By the action of this spring 16, normally, the small poppet part 12 closes the communication hole 11c formed in the poppet part 11b of the large poppet 11, and the spring force also acts on the large poppet 11. , the seat portion 14 is closed by the poppet portion 11b.

An orifice lid and a small hole 12a are formed in each of the poppets 11 and 12 as described above, so that the pressure in the supply passage 3 is guided to the pressure chamber 13.

Then, the spring receiving plate 15 is moved by the action of the spring 16,
When in contact with the stepped portion 17, a sufficient distance is maintained between the spring receiving plate 15 and the cylindrical portion 11a of the large poppet 11, so that the large poppet 11 can make a full stroke by that distance. .

Further, a small piston is connected to the side surface of the spring receiving plate 15 opposite to the spring 16, and a large piston 18 is connected to the small piston 18.

The pressure within the pressure chamber 13 acts on the small piston 18, while a pilot pressure for switching the control valve C1 that controls the swing motor M acts on the large piston 19.

Therefore, both pistons move according to the relative difference between the working pressure Pa of the arm cylinder S and the simultaneous operation rotation setting pressure Pp. / area of small piston) x pilot pressure of control valve C1.

When the first operating pressure Pa<the simultaneous operation rotation setting pressure Pp, both pistons 18 and 19 move down together with the spring receiving plate 15 against the spring 16. When the spring receiving plate 15 comes into contact with the upper end of the cylindrical portion 11a of the large poppet H1, the stroke of the large poppet 11 is regulated.

If the stroke of the large poppet 11 is regulated in this way, even if the pressure in the parallel passage 6 is
Even if the poppet portion 11b acts on the seat portion 14
keep it closed. Therefore, in the pressure action of the parallel passage 6 at this time.

Only the small poppet 12 moves against the spring 16,
When the communication hole 11c is opened, the hydraulic oil in the parallel passage 6 is supplied to the arm cylinder S via the orifice lid formed in the large poppet 11.

That is, in a state where 1 working pressure Pa<simultaneous operation swing setting pressure Pp, the oil discharged from the pump P is preferentially supplied to the swing motor M.

When the operating pressure pa exceeds the simultaneous operation rotation setting pressure pp, both pistons 18 and 19 are held at the upper position shown in the drawing, so that the spring receiving plate 15 also comes into contact with the stepped portion 17 due to the action of the spring 16. .

In this state, the large bopper (11) can make a full stroke, so the large bopper (11) opens the seat portion 14 due to the pressure action of the parallel passage 6.

Therefore, the oil discharged from the pump P is supplied to both the swing motor M and the arm cylinder S. Furthermore, even if the swing motor M stops due to the action of an external force,
When the operating pressure Pa of the arm cylinder S becomes higher than the simultaneous operation rotation setting pressure Pp, the large poppet 11 opens, thereby eliminating the conventional inconvenience.

Further, with the above configuration, the simultaneous operation rotation setting pressure can be arbitrarily changed by adjusting the area ratio of both pistons, the pilot pressure for switching the control valve C1, the opening degree of the orifice lid, etc.

In the above embodiment, the load check valve R is divided into the large poppet 1 and the small poppet 12, but for example, the conventional load check valve shown in FIG. 2 may be used as is.

Further, the small piston 1 and the large piston 19 may be combined into a stepped piston.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional device. P...Pump, M and S...Swivel motor and arm cylinder as actuator, C,, C2...Control valve, 6...Parallel passage, R...Load check valve, 10... Neutral flow path, 18... small piston, 18... large piston.

Claims (1)

[Claims] A single pump operates multiple actuators and is equipped with a control valve corresponding to each actuator, and these control valves connect the neutral flow path in tandem, while also connecting in parallel via a parallel path. Moreover, pilot pressure is applied to a load check valve provided on a specific control valve to adjust its opening degree, and the actuator connected to the control valve is connected to other control valves. In a hydraulic control device configured to preferentially drive an actuator, a specific pilot-operated control valve is provided with a large piston and a small piston with different pressure-receiving areas either integrally or separately, and the small piston is applies the operating pressure of the actuator connected to the control valve, applies pilot pressure to the large piston to switch the control valve, and operates the load check valve according to the acting force on the large piston and the small piston. Hydraulic control device configured to control the opening degree of.