JPH0272204A - valve - Google Patents

Abstract

PURPOSE:To select a spool with pilot pressure oil as well as to make it feedable to an actuator by installing a throttle part, interconnecting a chamber at the actuator side to that at the pilot pressure feed side, in a valve body, and interconnecting differential pressure in front and in the rear of this throttle part to an oil chamber interconnecting the spool through a drill hole. CONSTITUTION:Pressure oil fed to chambers 32, 73 at the pilot pressure feed side passes through a throttle part and flows into chambers 35, 50 at the side of a working machine actuator. Then, differential pressure is produced in front and in the rear of this throttle part, and the differential pressure is fed to each of oil chambers 41, 47 of a spool 18 by way of a drill hole, whereby this spool 18 comes to an interconnecting position so that a chamber 65 at the main pressure oil feed side and the chambers 35, 50 at the working machine actuator side are interconnected with one another. Next, the pressure oil fed to the chamber 65 at the main pressure oil feed side is joined together with that fed to the chambers 32, 73 at the pilot pressure feed side and fed to a working machine actuator. Accordingly, the pilot pressure oil selecting the spool 18 is fed to the working machine actuator, thus it is effectively utilizable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a valve that supplies pressure oil to a work machine actuator that drives a work machine such as a construction machine.

For example, a spool is slidably provided in the valve body, and this spool is held in a neutral position using a spring force so that pressure oil from the hydraulic pump is not supplied to the work equipment actuator, and the spool is pressurized by pilot pressure oil supplied to the oil chamber. Pilot-operated valves that are slid into an oil supply position are known.

[Problem to be solved by the invention]

With such pilot-operated valves, the spool of the valve can be slid by switching a small pilot valve, reducing the operating force and allowing switching by remote control, but on the other hand, there is no pilot in the oil chamber. The pilot hydraulic pump for supplying pressure oil is
The discharge pressure oil is only supplied to the oil chamber and can be used for other purposes, which is wasteful.

Therefore, an object of the present invention is to provide a valve that can solve the above-mentioned problems.

[Means and effects for solving the problem] A constriction is formed in the valve body to communicate the chamber on the work equipment actuator side and the chamber on the pilot pressure supply side, and the differential pressure generated before and after this constriction is transferred to the spool at the communicating position. This is a valve that communicates with the oil chamber through a drilled hole.This allows the spool to be switched to the communication position using the pilot pressure oil supplied to the chamber on the pilot pressure supply side, and also allows the pilot pressure oil to be transferred to the work machine. It can be supplied to the work equipment actuator from the chamber on the actuator side.

〔Example〕

Hereinafter, the present invention will be explained with reference to FIGS. 1 to 3.

1 and 2 in Figure 3 are the first. A second pump, 3 is a first control valve for blades, 4 is a second control valve for tilting, 5 is a third control valve, 6 is an unloading valve, and 17 is a main valve which is a valve according to the present invention. , 55 is a shuttle valve. The first control valve 3 and the unload valve 6 constitute a proportional control valve A with pressure compensation.

7F[a The third control valve 5 includes a valve body 91, which is provided with a spool hole 92, and which has a chamber 23 that communicates with the spool hole 92.
, 30, 75.7753.22, 24.28 are provided. A spool 19 is inserted into the spool hole 92,
Spring seats 94,95 are provided at the ends of the spool 19 in contact with the respective shoulders, and a spring 96 is provided between the spring seats 94,95. The chambers 22, 24 communicate with the chamber 28 via a passage 97, in which the check valve 27 is provided.

The passage 97, the check valve 27, the chamber 77, and the chamber 30 form an operating pressure circuit section E, and the passage 97, the chamber 23, and the passage 97
, chamber 24, and chamber 53 form a pilot pressure circuit section F.

The main valve 17 includes a valve body 98, and the valve body 98 is provided with a spool hole 99°100101.

The valve body 98 is provided with a chamber 49.51 that communicates with the spool hole 99, the valve body 98 is provided with a chamber 32.35 that communicates with the spool hole 100, and the valve body 98 is provided with a chamber that communicates with the spool hole 101. The setting is 50°73.

A spool 18 is inserted into the spool hole 99, and the spool 18 is supported by springs 48, 48' at both ends.
Both ends of the spool hole 99 are formed into oil chambers 41 and 47, and these form the first valve part I.

A spool 33 is fitted into the spool hole 100, and is held neutrally by a spring 38. The spool 33 has drill holes 37 and 42 formed therein, and these form the first valve part G.

A spool 71 is inserted into the spool hole 101, and this spool 71 is held neutrally by a spring 38'.The spool 71 is also formed with drilled holes 79 and 91, which allow the second A valve portion H is formed.

The valve body 98 is provided with a shuttle valve 40,45.

The chamber 35 communicates with the chamber 51 via a suction valve 140.

Port 40a of shuttle valve 40 communicates with chamber 102 via passage 39, port 40b of shuttle valve 40 communicates with chamber 80 via passage 90, and port 40C communicates with chamber 102 via passage 39.
communicates with chamber 41 via passage 90'.

Port 45a of shuttle valve 45 is connected to chamber 1 through passage 92.
03, another port 45b communicates with the chamber 43 via the passage 44, and another port 45C communicates with the passage 4
6 into chamber 47. A check valve 66 is provided in the passage 104 from the chamber 65 to the chamber 49.

The shuttle valve 55 includes a valve body 7.
A spool hole 110 is provided in the spool hole 110.
A plug 57 is fitted into the end of the . Spool hole 11
0 is provided with a spool 12, and the spool 12
A piston 56 is fitted into the end of the cylinder. Spool 12
is urged toward the plug 57 by a spring 58.

The valve body 7 is provided with a chamber 9.5960 which communicates with the spool hole 12.

The discharge side of the first pump 1 is connected to the chamber 65 of the main valve 17 via a pipe 64, and the discharge side of the first pump 1 is connected to the boat 6 of the unload valve 6 via a branch point 63.
It is connected to a.

The chamber 51 of the main valve 17 is connected to the tank 1 via piping 70.
It leads to 11. Main knob Lube 17 room 35.50
is connected to the ripper cylinder 1B, which is the working machine actuator B, via piping 36.68. Also, the main nokuru rube 17 room.

32.73 is connected to the chamber 30.75 of the third control valve 5 via a pipe 31.74.

The discharge side of the second pump 2 is connected to the passage 97 of the third control valve 5 via a pipe 20.
Tilt cylinder 1, which is the other work equipment actuator C,
Twelve second control valves 4 are provided. The chamber 23 of the third control valve 5 is connected to the boat 6b of the unload valve 6 via a pipe 21, and the chamber 23 is connected to the boat 3a of the first control valve 3 via a pipe 15. .

The first control valve 3 operates the blade cylinder 113, which is another working machine actuator D. The chamber 77 of the third control valve 5 is connected to the tank 1111 via a pipe 78.

The chamber 53 of the third control valve 5 is connected to the chamber 59 of the shuttle valve 55 via the pilot line 54, and the chamber 60 of the shuttle valve 55 is connected to the unloader via the pilot line 62. Valve 6 pilot boat 6d
It is connected to.

A throttle 11 is installed in this pilot pipe 62.

A pilot pipe line 115 branches off from the pipe 15, and is connected to the pilot pipe line 115 (and to the pilot port 6e of the unload valve 6).

The chamber 9 of the shuttle valve 55 is connected to the shuttle valve 10 via the /kuiro-soto line 13.

Operation of the device of the embodiment When the engine is rotating and the first, second and third control valves 3, 4.5 are in the neutral state as shown in FIG. Since it is in the closed state, the pilot pressure at the left end of the unload valve 6 increases, and the spring side pressure at the right end of the unload valve 6 is connected to the chamber 9 through the throttle 11 and the groove 8 cut in the spool 12 of the shuttle valve 55. , pilot line 13
from the shuttle valve 10 through the first control valve 3
Since it is connected to the tank 111 through the drain passage 14, the unload valve 6 is in the state shown in FIG. 4, and the first pump 1 is in the unload state at low pressure. - The discharge side of the pump 2 is connected to the unload valve 6 by a pipe 15 through the second and third control valves 4.5, and the unload valve 6 communicates with the boat side as shown in Fig. 2. The second pump 2 is also in an unloaded state at low pressure.

Note that when the first control valve 3 and the third control valve 5 are operated simultaneously, the first control valve 3 is given priority. Therefore, spool 1 of shuttle valve 55
2 is pressed against the plug 57, and the unrotating knob 6 connects the first and second control valves 3 to the first control valve 3.
Take a position where you can supply the ponds of pumps 1 and 2. However, in this case, the first control knob 3 and the main valve 1
Since the relationship with 7 is a parallel circuit, the pump oil flows to the side with the lighter load. In the circuit shown in FIG.
Simultaneous operation of the third control valves 3 and 5 is practical, and no particular consideration is given to flow rate distribution in that case.

In the shuttle valve 55, the spool 12 and the piston 56 are provided with a difference in area in order to prioritize the circuit of the first control valve 3 as described above.

When the spool 19 of the third control valve 5 is operated to the pulled state, the flow of the second pump 2 that was flowing from the pipe 20 from the chamber 22.24 of the third control valve 5 through the constriction 25.26 of the spool 19 is At the same time, the check valve 27 is forced open and the flow passes from the chamber 28 around the constriction 29 of one of the spools to the chamber 30.
Leads to. It flows from the chamber 30 through the conduit 31, from the chamber 32 of the main control valve 17, through the notch 34 of the spool 33 and into the chamber 35, and at the same time flows into the bottom side of the ripper cylinder 16 through the conduit 36, passing through the notch 34 of the spool 33. The pressure on the previous high pressure side is transmitted through the passage 3 through the chamber 102 of the spool 33 through the drill hole 37 made in the spool 33.
9. The air is guided through the shuttle valve 40 to a chamber 41 which is a pressure chamber at one end of the spool 18 of the main valve 17. On the other hand, the pressure on the low pressure side after passing through the notch 34 of the subur 33 is guided from a drilled hole 42 in the spool 33 through a chamber 43 at one end of the spool 33 to a chamber 47 which is a pressure chamber at the other end of the spool 18. . As a result, the spool 18 moves until the differential pressure between the pressure chambers 41 and 47 is balanced with the spring 48 in the chamber 47, and the communication between the chamber 49 and the chamber 35 of the main valve 17 is changed from the closed state to the open state. . Further, the relationship between the chamber 50 connected to the rond side of the ripper cylinder 16 and the chamber 51 which is the tank port of the main valve 17 is changed from a quiet state to an open state.

In addition, by the pull signal of the control valve 5 of the force cylinder 3, the notch groove 52 cut out in the spool 19 changes the state between the chamber 24 and the chamber 53 from closed to open, and the pump pressure is changed to the pilot pipe 5.
4 acts on the piston 56 provided in the spool 12 of the nyatle valve 55, which is held down by the plug 57, so that the spool 12 moves to the left against the spring 58, separating the chamber 60 and the chamber. The notch 8 which opened the spool 9 is closed, and the chambers 59 and 60 are opened through the constriction 61 of the spool 12 and are led to the spring chamber side of the unload valve 6 through the pilot pipe 62 and the throttle 11. As a result, the pressure of the second pump 2 forces the unload valve 6, which was in the unload state shown in FIG. 2, into the on-load state shown in FIG. The check valve 66 is opened by pushing the check valve 66 from the chamber 65 which is the pump port of the main valve 17 through the chamber 64, and through the constriction 67 of the open spool 18, it joins the flow rate of the second pump 2 in the chamber 35, and the cylinder The return flow from the cylinder rod side extends from the ripper cylinder 16 to the bottom side, flows from the pipe 68 to the chamber 50, passes through the six constrictions of the spool 18 in the open state, and from the tank port chamber 51 to the pipe 7.
0 and returns to tank 111.

Similarly, when the spool 19 of the third control valve 5 is placed in the pushed position, the ripper cylinder 16 can also be driven to the contraction side.

In addition, the previous main bar! In the rev 171, if the ripper cylinder 16 is extended even if the flow rate of the first pump 1 merges with the flow rate of the second pump 2,
It is on the downstream side with respect to the chamber 32. Therefore, the flow rate of the first pump 1 merges with the flow rate of the second pump 2 in the chamber 35, and the flow rate of the first pump 1 flows into the chamber 35.
The pressure in the branch chamber 32 where the pressure in No. 5 has increased is increased. Because of this, the pressure difference is maintained.

In addition, since it uses the differential pressure caused by the flow of the water, the ripper
It is not affected by the load pressure of the cylinder 15 or the direction of the load.

That is, if the extension side of the ripper cylinder 16 is the free fall side in FIG. 1, then the flow rate from the rod side of the ripper cylinder 16 to the chamber 50>
The flow rate can be from the chamber 35 to the bottom side of the ripper cylinder 16.

In this case, the differential pressure is between chamber 50 (upstream side) and chamber 73 (downstream side).
The pressure in chamber 50 is determined by the pressure in chamber 50.
0. It is led from port 4c of shuttle valve 40 to chamber 41 via passage 90, causing spool 18 to move downward in FIG.

The oil of the first pump 1 thus flows into the chamber 35 and enters the bottom side of the ripper cylinder 16.

Also, even when the engine is stopped and there is no flow rate from the first and second pumps 1゜2, it is necessary to lower the working machine to the ground. For example, if we consider the case where the ripper cylinder 16 is pushed by its own weight, When the spool 19 of the third control valve 5 is placed in the pulled position, the return flow from the head side of the ripper cylinder 16 flows from the pipe 68 through the chamber 50, through the notch 72 of the spool 7, and from the chamber 73 to the pipe 74. It passes through the chamber 75 of the third control valve 5, passes through the constriction 76 of the spool 19 in the open state, and returns to the tank 111 from the chamber 77, which is a tank boat, through a pipe 78. Due to the pressure difference generated before and after the notch 72 of the spool 71 due to the simultaneous flow, the pressure is led to the pressure chamber 41 of the spool 18 through the seven perforations of the high pressure side spool 71, through the chamber 80, the passage 90, and the shuttle valve 40. The low pressure side is led from a through hole 91 of the spool 71 to a chamber 47 which is a pressure chamber of the spool 18 via a passage 92 and a shuttle valve 45. As a result, the spool 18 is pushed downward, and the relationship between the chambers 50 and 51 changes from closed to open, and the return flow from the cylinder head side passes through the constriction 69 of the spool 18 and goes through the piping 70 to the tank 111. Return to tank 111. In this case, since the chamber 51 and the chamber 35 communicate with each other via the suction valve 140, when the ripper cylinder 1G is extended, the chamber 51 communicating with the tank 1]1 communicates with the chamber 35 via the suction valve 140. supply ura to. For this purpose, oil is supplied to the bottom side of the pan cylinder 1B. In this case, even if the engine is stopped as described above, the spool 18 of the main valve 17 can be switched by operating the third control valve 5. Emergency braking (when stopped) is possible.

〔Effect of the invention〕

The pressure oil supplied to the chamber 32.73 on the pilot pressure supply side passes through the throttle part to the chamber 35.50 on the work machine actuator side.
A pressure difference is generated before and after the constriction part, and the pressure difference is supplied to the oil chambers 41 and 47 of the spool 18 through the through hole, and the spool 8 is in the communication position and the main pressure oil supply side is Room G
5 communicates with chamber 35.50 on the work machine actuator side,
The pressure oil supplied to the chamber 65 on the main pressure oil supply side and the pressure oil supplied to the chamber 32.73 on the pilot pressure supply side are combined and supplied to the work machine actuator.

Therefore, the valve can effectively utilize pilot pressure oil for switching the spool 18 by supplying it to the working machine actuator.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being an explanatory diagram of the configuration, and FIGS. 2 and 3 being explanatory diagrams of the operation of the unload valve. 18 is a spool, 32.73 is a chamber on the pilot pressure supply side, 41.47 is an oil chamber, 35.50 is a chamber on the work equipment actuator side, and 65 is a chamber on the main pressure oil supply side.

Claims (1)

[Claims of Claims] A spool 18 that connects and shuts off the chamber 65 on the main pressure oil supply side and the chambers 35 and 50 on the work machine actuator side in the valve body 98.
The spool 18 is held in the cutoff position by a spring force and placed in a communication position by the pressure oil in the oil chambers 41 and 47, and the valve body 98 is provided with pilot pressure supply side chambers 32 and 73.
, a throttle section that communicates these chambers 32, 73 with the chambers 35, 50 on the work machine actuator side, and a pressure difference generated before and after this throttle section is transferred to the oil chambers 41, 47 of the spool 18.
A valve characterized in that a through hole is formed for supplying a supply to each valve.