DE1775602B1 - HOLDING AND RELEASING DEVICE FOR SPOOLS OF HYDRAULIC DIRECTIONAL VALVES - Google Patents

Description

(31 or 32) existing throttle opening through an annular gap (30) between the shaft of the Control slide and the bore of the cutting disc (29) can be formed.

3. Device according to claims 1 or 2, characterized in that the cutting disc (29, Fig. 1) fixed in the cylinder of the valve housing is arranged, whereby the pump

(35) is arranged loaded, wherein the consumer line (34 a) can be closed and opened by the partition.

5. Device according to one of claims 1 to 4, characterized in that, depending on the type of the directional control valve both at one end and at both ends of the control slide can be.

3 4

Complete overlying surfaces at the end and the free return 25 in connection. Both KoI

that the behind the separating chambers of the working cylinder 20, seen in the direction of flow, are closed.

disc located subspace sen via an open line, namely the lines 19, 34 through the control

with the same consumer chamber in connection disk 7, the line 19,17 through the control disk

stands. Further features are claims 2 5 10 and the line 18, 16 through the control disk 9.

to see 5. If the control spool is pulled, the

In the drawing, the invention is partly schematic subspace 31 of the full pump pressure p _v because it is with the

table, partly represented in symbols. Pump branch line 22 is connected. The printing

F i g. 1 is a central longitudinal section of a Wegeven- means opens the check valve 33, the past

tils for a double-acting consumer with io, spring force determined a reduced pressure p ₂

an embodiment of the inventive feature, which is in the lines 34,19,17 as well as in the

direction; Subspace 32 prevails, which is down through the

F i g. 2 shows a cross section of FIG. 1 after control disk 8 is completed. The pressure difference

the line II-II; in the subspaces 31 (^ ₁ ) and 32 (p ₂ ) can during

Fig. 3 is the lower part of the operation in the drawing, i.e. as long as there is flow,

Directional valve according to FIG. 1, but not balanced with another by the throttle cross-section30

Embodiment of the holding and releasing device. as this is the case even with low currents

With 1 the valve housing of FIG. 1 and that is too small. So it acts on the control disk 7 of the

F i g. 2, with 1 α that of FIG. 3 designated. It ent- higher pressure p _v on the control disk 8 of the low-

holds the cylinder 2 or 2 α for the control slide 3 20 more pressure p ₂ . The control slide is therefore

or 3 a. Five control disks 4, 5, 6, 7 and 8 or an upward force in the drawing

Ta and 8α act when moving the tax exerted, which is larger than the force of the

Slider in a manner familiar to those skilled in the art, return device 28. It holds the control slide

with the annular chambers 11, 12, 13, 14 and 15 together in the pulled control position. But hear that

men and represent the in the explanation of the we- 25 flow on the way 22, 31, 33, 34 from deliberate

the connections specified. Two or unwanted causes, then Ap collapses

open more control discs 9 and 10 or 10 α men, whereby the control slide is released and from

and close the two at right angles to the intersection of the return device in its neutral position

plane of the drawing in the cylinder 2 or 2 α is conveyed.

opening channels 16 and 17 or 17 a, which over 30 In the pulled control position is the

Lines 18 and 19 to the double-acting lower piston chamber of the working cylinder 20

guide cylinder 20. Since the control discs 9 and the line 19 is pressurized, while the upper

10 have axial openings 27, the piston chambers on both sides via the lines 18 and 16 and

cylinder spaces located by them are always connected. via the axial opening 27 with the pressureless

The annular chambers 12 and 14 are connected via two branch 35 return lines 24.

Lines 21 and 22 with the pump P in connection. In the pressed, the arrow opposite manure, which is controlled by a pressure relief valve 23, the working cylinder is reversed. Acted from the annular chambers 11, 13 and 15. This is understandable to the person skilled in the art without introducing connections 24 or 25 or 26 for detailed explanations, loose return. By means of a return device 28 familiar to the person skilled in the art, the control slide concept is shown in FIG. 3 shown. Here the over 3 held in the drawn neutral position separating disk 29 α sealing and sliding in the valve or returned into it, if not other forces cylinder 2 a arranged, and it is predominant in the drawn. Neten neutral position of the control slide 3 a

In the exemplary embodiments, the invention 45 is in its stop position by a compression spring 35

Appropriate holding and release device only held at that. In doing so, it closes the to the working cylinder

lower end of the control slide provided; it can lead line 34 α, 19 α from. The cutting disc

can of course also be arranged at both ends, 29 α also takes on the task of the cutting disc

when the control slide also functions as the check valve 33 in both control positions 29.

should be held and solved. In example 50, the partial space 31 α is acted upon by the pump pressure P ₁

According to FIG. 1, the following components belong to the beats, so the separating disk 29a becomes so through him

Device according to the invention: A cutting disk moved far down that in the line 34 a

29, which is firmly connected to the cylinder wall 2, the reduced pressure p ₂ arises, where Ap again-

and the inside diameter of which is approximately constant with the slide shaft. The rest of the function is

a throttling annular gap 30 of small transverse 55 the same as that on FIG. 1 explained

cut forms. It is in the pulled position. The two control disks 9 and 10 have nothing

(Arrow) of the control slide of the cylinder space between to do with the invention. They serve in well-known

see the switching disks 7 and 8 in two sub-spaces way to produce the so-called floating

31 or 32 divided. A position leads from subspace 31 by rotating the control slide by 90 °.

Connection via a check valve 33 and via 60 Their mention is only intended to show that they are the

the lines 34 and 19 to the working cylinder 20.

the same chamber of the working cylinder also leads to the.

From the other subspace 32 a completely open connection can be easily recognized by the person skilled in the art, connection via the axial openings 27 and the line that the holding and releasing devices 17 and 19 according to the invention are also used in directional control valves for single-acting drugs The mode of operation is as follows: In which the drawing can be used. It is also advantageous if the control slide is in a neutral position that it has only a single movable component, namely both branch lines 21 and 22 of the pump P with the closing body 33 and 29 α of the non-return valve

tils, which has a double function. Firstly, it effects the holding and releasing device required pressure difference, and its non-return function enables the application at the same time the so-called negative coverage, the explanation of which appears unnecessary to the person skilled in the art. Finally, it can be seen that the outer housing chambers 11 and 36 (FIG. 1) in every operating position of the control spool are in connection with an unpressurized return. This will the sealing of the rod of the control slide, which is guided to the outside from the pressureless housing chamber 11 3 simple and reliable.

It is common for the housings of several directional control valves to be combined to form a unit will. This is of course also possible with the one provided with the subject matter of the invention. The opening 25, which is connected to the return line in the case of the individual valve, is then used to forward the pressure fluid into the connected second directional valve.

1 sheet of drawings

Claims (2)

Claims: holds the control slide moved into a control position by compressing a counteracting return spring by means of a pressure difference acting on it and releases it by automatically canceling this pressure difference so that the return spring returns the control slide to its neutral position, with the one in a cylinder of the Valve housing sliding control slide with two of its switching disks 1. Holding and releasing device for control slide of hydraulic directional control valves with a neutral one
and one or two control positions for steering
of consumers, who hold the control slide, which has been moved into a control position, by compressing a counteracting return spring by means of a pressure acting on it and with the cylinder, a closed space difference and forms it automatically, which dissolves this pressure difference in two parts by means of a separating disk , so that the spaces are subdivided, which however are connected to the control slide in its new opening by a throttle return spring and which returns the central position in the direction of flow, with the partial space located in front of the separating disk in a control area with the position in a cylinder of the valve housing 15 is connected to a pump inlet and via a spring-loaded, ses displaceable control slide with two of its closing members, which can be opened by the pump pressure, with switching disks and with the cylinder one is connected to a chamber of a consumer. forms a closed space, which is separated by a. According to an older proposal, there is already a Separating disk is divided into two sub-spaces, the hydraulically acting holding and releasing device but connected by a throttle opening 20 for directional control valves, where the required pressure difference is, and which, seen in the direction of flow, is generated by damming the return flow before the reference. At Partial space with a pump located on the separating disk is disadvantageous in that it is outside the hydraulic penzulauf as well as a spring-loaded, throttle bodies from the directional control valve and a common Pump pressure to be opened closing member with pressure holding valve must be provided and because a chamber of a consumer, this holding and releasing device is not for easy thereby marked that the acting consumer can be used because with her no separate return line is available, but flow and return via one and the same Line flow. According to another older proposal, another holding and releasing device of the genus was created, which is partly located within the control slide in the inlet to the consumer. To the Generation of the required pressure difference is in the 2. Apparatus according to claim 1, characterized in that the valve slide is a spring-loaded, in the direction of flow indicates that the throttle valve opening between the subspaces to the consumer is arranged. This is followed by a check valve built into the valve housing. The establishment is preferably intended for single-acting consumers. It is possible with considerable effort to make them functional for double-acting, but the effort is disadvantageous. Furthermore is it is unfavorable that the check valve for connecting the consumer to the return by means of pressure-openable closing member is pushed open by a part that is mechanically moved from the outside known spring-loaded check valve (33) is. must become. Furthermore, it is a z. Z. not ver-4. Device according to claims 1 or 2, avoidable complication that the chamber from which characterized in that the separating disk moves the actuating rod of the control slide towards the outside (29a, Fig. 2) is guided in the cylinder of the valve housing, is acted upon by the pump pressure. the axially sliding, closing on the cylinder wall 50 sealing difficulties at high pressures and known against the pump pressure with a spring. After all, the directional control valve already contains for only single-acting consumers, in addition to the control slide, five mechanically moved ones, i.e. wearable parts. The invention is based on the object of providing a hydraulically acting holding and releasing device create, which without difficulty in directional control valves for single as well as for double acting consumers is usable. The whole combination of directional control valve and holding and releasing device should be disregarded only contain a single mechanically moving part of the control slide and springs. According to a further sub-task, the housing chambers at both ends of the control slide should be The invention relates to a holding and releasing device that is never subjected to 65 pump pressure, direction for control slide hydraulic Wegeven- To solve this problem it is provided that tile the closed space with a neutral and one or two control disks Positions for controlling consumers, which are opposite to those in the longitudinal direction of the control slide Switching disks (7 or 8) the closed space (31,32) with their in the longitudinal direction of the The end of the control slide (3) and that of the opposite surfaces are in the direction of flow Subspace (32) located behind the separating disk (29) via an open line (17, 19) is in connection with the same consumer chamber (30).