WO1996002781A2

WO1996002781A2 - Vadraulic valve

Info

Publication number: WO1996002781A2
Application number: PCT/EP1995/002713
Authority: WO
Inventors: Ernst Mateja
Original assignee: Saarberg Hydraulik Gmbh
Priority date: 1994-07-15
Filing date: 1995-07-12
Publication date: 1996-02-01
Also published as: DE4425084C2; DE4425084A1; AU3077895A; WO1996002781A3

Abstract

In an electrically controlled hydraulic valve, in particular a pilot valve used in mining industry hydraulic equipment, a piston (9; 10) arranged in a line (12-16, 21) connected to the pressure source is provided with an axial bore (21) that forms part of the line. The pressure in the line is applied on one front face (16) of the piston. A slide (6) that can move transversely to the piston (9; 10) to actuate the valve, a rotary body or the like, lies on the other front face of the piston (9; 10). The slide (6), rotary body or the like has a bore (29) that prolongs the line and whose inlet is located in the closed position next to the outlet of the bore (21) of the piston (9) and in the open position directly at the outlet of the bore (21) of the piston (9). This construction principle is applied in several different embodiments of the invention.

Description

Description:

"Hydraulic valve"

The invention relates to a hydraulic valve, in particular with electrical actuation, in particular as a pilot valve in mining hydraulics.

In the electric pilot control valves, which are used to control larger hydraulic valves to act on hydraulic cylinders, a spherical closing body is usually pressed onto a sealing seat with the pump pressure in the closed position. To open the valve, a plunger lifts it, which in turn is pushed forward by another spherical closing body, which is pressed onto its sealing seat and closes the return line. A lifting magnet acts on the other closing body via a linkage. When the solenoid is deactivated, the return to the closed position is again effected by the action of the pump pressure on the former closing body, usually in conjunction with a return spring.

Since this takes place abruptly according to the principle of the check valve, the closing body and the sealing seat are increasingly deformed, with the result of leakage.

The various known pilot control valves have this basic function and their shortcomings in common.

The invention has for its object to provide a hydraulic valve that can be opened with little force and closes without kickback.

According to the invention, in the line of the valve connected to the pressure source, a piston forming part of the line with an axial passage is arranged, which is acted upon on one end face by the pressure prevailing in the line and bears on its other end face against a part which can be displaced transversely to the piston for actuating the valve and which has a passage which extends the line, the inlet of which, in the closed position, lies next to and in the open position directly at the outlet of the passage of the piston.

The movement of said part relative to the piston into the open position does not take place against the pump pressure, but only by overcoming the friction between the displaceable part and the piston. With the same power and lifting work e.g. A solenoid can open and close a larger passage cross section. This also reduces the risk of clogging due to dirt.

The closing can in turn be done in the same way by the sliding drive, e.g. the solenoids.

There is no impact on a sealing surface in either movement.

The advantage of the freedom from impact is also achieved if the possibility of generating both the opening movement and the closing movement with the sliding drive is not fully used and the one of the two movements, in particular the closing movement, is wholly or partly by a the other movement tensioned spring is effected.

In order to return the valve to the closed position without a spring tension in the event of a power failure, a capacitor is advantageously provided as a store or a battery for the energy required for the closing movement.

The already simple construction of the valve can be made very simple with a small piston from a seal to the displaceable

Partly attached, elastic plastic with a low coefficient of friction and high

Strength.

A metal piston with a front coating made of an elastic

However, sealing material would also be possible.

In order to increase the surface pressure of the piston on the displaceable part and thus to increase the sealing effect, the piston is preferably spherical or conical on the end face in question. For high-pressure hydraulics above 300 bar, for example, the piston has a diameter of 2.5 to 4.0 mm, a length of 4.0 to 7.0, preferably 5.0 to 6.0, mm and a diameter of Passages from 0.5 to 1.2 mm.

In a particularly simple variant of the invention, the displaceable part is a slide, in which the passage runs between two opposing, preferably flat, surface sections, and at the outlet of this passage another piston of the type mentioned closes accordingly followed by a continuation line.

In order to establish the connection of the consumer to the return line of the hydraulic system, which is usually desired in the closed position of the valve, in the closed position, the passage of the further piston is expediently connected to a further passage which is arranged in the slide and which is connected to the return of the hydraulic Systems connects.

The further passage only needs to lead somewhere out of the slide, expediently at the end, as a rule the piston abuts the displaceable part, ie in the case of the slide practically the entire end section thereof, with regard to leakage liquid escaping here during the displacement process there will be a sealed area connected to the return of the hydraulic system; this area can be practically the entire interior of the valve with the exception of the pressure medium line.

In a second variant, the displaceable part is a slide, in which the passage is formed by a transverse bore forming its entrance, a subsequent longitudinal bore and a possibly multiple radial outlet; the arrangement in the area of this outlet is designed in a manner known per se as a slide valve with a housing in which the outlet opens into an annular chamber which is preferably sealed on both sides between the housing and the slide by sealing rings and to which a further line is connected.

In a third variant, the displaceable part is a rotatably mounted body which can be displaced with respect to the piston with a, preferably flat, end face or a, preferably spherical, peripheral surface.

The spherical peripheral surface has the advantage in comparison with a cylindrical that the piston can have a correspondingly concave contact surface with it, which for the cylindrical circumferential surface would require a rotation lock of the piston that would not be possible with reasonable effort.

In the case of the rotatable body, the passage is preferably through an oblique bore (entrance on the end face) or radial bore (entrance on the circumferential face), possibly in a recess, forming its entrance, a subsequent longitudinal bore in an axis holding the rotatable body and a, possibly multiple, radial outlet formed therefrom; the outlet opens into a chamber of a housing, which is preferably sealed on both sides between the housing and the axis by sealing rings and to which a further line is connected.

In the case of an electrical pilot control, the displacement drive will be a lifting magnet for the above-mentioned slide or a piezo actuator, preferably via a lever which acts on the lever, and a rotary magnet for the above-mentioned rotatable body or a lifting magnet acting on a swivel arm or piezo actuator.

However, the valve is not limited to electrical actuation.

The drawings show exemplary embodiments of the invention.

1 to 5 each show an electric pilot valve in axial section.

Through drilled and milled recesses in a block 1 and separately manufactured inserts 2 and 3, a valve housing is created with a pump connection P, two consumer connections X and Y and a return connection R.

The inserts 2 and 3 have a cylindrical shape and sit in a corresponding cylindrical recess in the block 1, which is accessible by removing a screwed-on cover 4.

Two narrower cylindrical recesses 5 lead at right angles into the aforementioned recess and cross them. A slide 6 to be actuated by a lifting magnet is guided in the recesses 5 and sealed at 7. The drawing is cut off in front of the solenoid.

The insert 2 on the left in the drawing is supported against the end of the first-mentioned cylindrical recess and, on the other side, presses with a piston 8 against the left slide 6, which is designed here as a flat cuboid. The middle insert 3 presses with two pistons 9 or 10 against the left and right slide 6. The Right insert 2 presses with a piston 1 1 against right slide 6 and is supported on cover 4 on the other side.

The middle insert 3 is connected to the pump connection P through a bore 12. The bore 12 opens into an annular recess 13 on the circumference of the insert 3, which is sealed on both sides by sealing rings 20 between the insert 3 and the block 1. From the annular recess 13, a transverse bore 14, possibly a second one at right angles, leads into the insert 3, where an axial bore 15 connects. The axial bore 15 is expanded to a cylinder chamber 16 at both ends of the insert 3. In this, the piston 9 or 10 is arranged under sealing by a sealing ring 17 located in a groove of the insert 3 and is preloaded by a compression spring 18. The pistons 9 and 10 have an axial passage 21 approximately of the diameter of the axial bore 15. At the end, they are conical, so that the outlet of the passage 21 is only enclosed by a narrow, annular contact surface of the piston with the slide 6.

The pistons 8 and 11 opposite the pistons 9 and 10 in mirror image are likewise formed and, in the inserts 2, also supported. Your passage is designated 22. Again aligned with this in the continuation of the cylinder space is an axial bore 23, which is connected by at least one transverse bore 24 to an annular recess 26, which is sealed at both sides and from which a bore 27 leads to the outside, here to the consumer connections X and Y.

As shown in dash-dotted lines, the cylindrical recesses 5 are connected to the return connection R.

In the illustrated closed position of the valve, the pump pressure is applied to the slides 6 via the devices 12, 13, 14, 15, 16 and 21, where it is sealed by the pistons 9 and 10 made of an elastic plastic. The passages 22 of the opposing pistons 8 and 11, on the other hand, are located at the entrance of an angled passage 28 which is arranged in the slide 6 and opens at the end of the slide. The consumers are therefore over 27, 24, 23, 1 6, 22, 28 , 5 and the dashed connecting lines to the return port R connected to the return. In the open position, a straight passage 29 is brought between the pistons 8 and 9 or 10 and 11 by actuating the relevant slide 6, which connects the passages 21 and 22 to one another. The consumer in question is thus connected to the pump line. The piston 8 or 11, which is likewise made of elastic plastic, initially rests on the slide 6 only with the pretension of the spring 1 8. To the extent that the pump pressure builds up on this side, it is also pressed hydraulically from the cylinder chamber 16 to the slide 6. Insofar as there is a slight leakage of liquid between the pistons 8 to 11 and the slides 6, this reaches the return line R in the manner already mentioned. The entire area in question is sealed by the seals 7, 17, 20 and 25.

Only one of the sliders 6 is switched at a time.

The return stroke to the closed position is in turn carried out electrically by the lifting magnets.

The valve according to FIG. 2 is also designed in the form of a block with recesses and inserts.

The insert 3 can be found in the same. The connection between the insert 3 and the pump connection P is designated 19 here.

The slide 6 with the straight passage 29 are replaced here by slide 30, in which the passage is formed by a transverse bore 31, a longitudinal bore 32 and two groups of radial bores 33 and 34. The longitudinal bore 32 is closed by a plug 35 screwed into the end of the slide.

The cross section of the slider 30 is circular with the exception of a flat incision in the area of the transverse bore 31, where the slider 9 or 10 is to find a flat contact surface 36. In the area of the radial bores 33, 34, the slide 36 projects into one through two inserts

37 and 38 formed valve housing in the manner of a slide valve. The inserts 37 and 38 close together via webs 39 to form a gap 40. The stake

38 is screwed into the block. The insert 37 is pressed against the insert 38 by a spring 41.

An annular recess 42 on the inner circumference of the insert 37 is connected via the gap 40 to an annular recess 43 on the outer circumference of the insert 38, which is supplemented by an opposite recess in the block. From here, a drilled line 52 leads to the consumer connection X or Y. The spaces 42, 40, 43 are sealed against the block by sealing rings 44 and 45 and against the slide 30 by sealing rings 46 and 47.

A drilled return line 49 leads from a cavity 48 in the area of the piston 9 or 10 to the slide 30 to the return connection R. It is only visible on the left in FIG. 2 as a section shown in broken lines.

Seals 50 and 51 close off the hydraulic spaces in the direction of the lifting magnets which are also cut off in this drawing and actuate the slides 30.

The closed position is again drawn, in which the pump pressure ends at the slides 30. In the open position, the transverse bore 31 lies in the extension of the passage 29 of the piston 9 or 10 and thus gives the hydraulic medium the further path free via the longitudinal bore 32, which then lies between the sealing rings 46 and 47, the radial bores 33 and the radial bores 34 , the annular recess 42, the gap 40, the annular recess 43 and the line 52 after the consumer connection X or Y.

In the closed position, the same line sections connect the consumer with the return in reverse order, in that the transverse bore 31 then opens into the space 48, which is connected to the return connection R via the return line 49.

3 has a valve housing composed of three inserts 53, 54 and 55 arranged in a block, a spacer 56 being arranged between the inserts 54 and 55.

In the inserts 54 and 55 there is mounted an axis 57 passing through the spacer 56 and having at its end an axially supported on a flange 58 of a flat-cylindrical head 60 which is seated in the insert 54, bearing bush 59. The axis 57 is connected via a coupling 61 arranged in a recess of the insert 55 to a rotary magnet (not shown). Instead of the rotary magnet, a lifting magnet could also engage on the axis 57 via a swivel arm.

A piston 9, which is arranged in the insert 53 in the same way as the piston 9 in the insert 3, presses on the end face of the head 60. The axial bore 15 leading to the piston 9 here starts from the end face of the insert and is acted upon by the pressure medium connection P via a bore 62 and a cavity 63 of the block. In the drawn open position of the valve, a flat depression 64 adjoins the passage 21 of the piston 9 in the head 60, from which an oblique bore 65 leads to an axial bore 66 which extends further through the axis 57 up to two radial bores 67 as an outlet.

These open into a cavity 68 of the spacer 56, which in turn is connected to the intermediate space 70 between the inserts 54 and 55 via bores 69 which are radial to the axis 57 and which it secures. The intermediate space 70 is sealed on both sides by sealing rings 81 and 82. In the intermediate space 70, a bore 71 leads to the consumer connection X.

In order to close the valve, the rotary magnet rotates the axis 57 by an angle such that the recess 64 is adjacent to the end of the piston 9, separate from the end.

The consumer is now connected to the return port R via a cavity 72 surrounding the head 60, radial bores 73 and an annular space 74 of the insert 54 and a bore 75.

In FIG. 4 the axially arranged insert 53 of FIG. 3 is replaced by a radially arranged insert 76.

The piston 9 lies against the circumference of the head 60. From a recess 77 arranged here, a radial bore 78 leads to the axial bore 66 which is still present. The arrangement of the pump connection with the bore 62 and the return connection with the bore 75 are interchanged with respect to FIG. 3. A ball 79 takes over the radial support of the rotatably mounted parts 57, 60, 61 and 66.

4, the end face of the piston 9 lying against the circumferential surface of the head 60 is flat and must adapt to the one-dimensional curvature of the circumferential surface with its elasticity, according to FIG. 5 a corresponding basic shape is possible: there the circumferential surface 80 is spherical , and the end face of the piston 9 has a groove in the form of the same spherical surface section.

Claims

Claims:

1 . Hydraulic valve, in particular with electrical actuation, in particular pilot valve in mining hydraulics, characterized in that in the line connected to the pressure source (12-16.21; 19.13-1 6.21; 62.63.1 5, 16, 21) a piston (9; 10) forming part of the line is arranged with an axial passage (21), the piston (9; 10) on its one end face (16) with that in the line (1 2-16, 21; 19 , 13-1 6, 21; 62, 63, 1 5, 16,21) prevailing pressure and on its other end face on a part (6; 30; movable for actuating the valve transversely to the piston (9; 10); 60) is present, which is a passage (29; 31-34; 64-67.77.78) which extends the line (12-16.21; 19.13-16.21; 62.63.1 5.16.21) , 66,67), the input of which in the closed position is adjacent and in the open position directly at the outlet of the passage (21) of the piston (9; 10).

2. Valve according to claim 1, characterized in that the, preferably on its first end face (16) spring-loaded, piston (9; 10) is spherical or conical on its other end face.

3. Valve according to claim 1 or 2, characterized in that the piston (9; 10) consists of a sealingly on the displaceable part (6; 30; 60) plastic.

4. Valve according to claim 3, characterized in that the piston (9; 10) for high pressure hydraulics above 300 bar a diameter of 2.5 to 4.0 mm, a length of 4.0 to 7.0, preferably 5.0 to 6.0 mm and a diameter of the passage of 0.5 to 1.2 mm.

5. Valve according to one of claims 1 to 4, characterized in that the displaceable part is a slide (6) in which the passage (29) runs between two opposite, preferably flat, surface sections, and at the outlet of this passage (29) another piston (8; 1 1) of the type mentioned, which is followed by a further line (22.1, 6.23, 24, 26, 27).

6. Valve according to claim 5, characterized in that in the closed position to the passage (22) of the further piston (8; 1 1) connects another passage (28) arranged in the slide, which with the return (R) of the hydraulic Systems connects.

7. Valve according to one of claims 1 to 4, characterized in that the displaceable part is a slide (30) in which the passage (31 -34) through a transverse bore (31) forming its entrance, a subsequent longitudinal bore ( 32) and a, possibly multiple, radial outlet (33, 34) is formed therefrom, and the arrangement in the region of this outlet is designed in a manner known per se as a slide valve with a housing (37, 38) in which the outlet ¬ leaves in an annular chamber (42), which is preferably sealed on both sides between the housing (37,38) and the slide (30) by sealing rings (46; 47) and adjoins a further line (40,43,52) .

8. Valve according to one of claims 1 to 4, characterized in that the displaceable part is a rotatably mounted body (60) and with a, preferably flat, end face or a preferably spherical, circumferential surface relative to the piston (9) is.

9. Valve according to claim 8, characterized in that the passage through an inclined or radial bore (65 or 78), possibly in a depression (64; 77), its entrance, a subsequent longitudinal bore ( 66) in an axis (57) holding the rotatable body (60) and a possibly multiple, radial outlet (67) is formed therefrom and this opens into a chamber (68-70) of a housing, which is preferably on both sides is sealed between the housing and the axis (57) by sealing rings (81) and to which a further line (71) is connected.

10. Valve according to one of claims 5 to 7, characterized in that on the slide (6; 30) a solenoid or, preferably via a lever increasing the path, engages a piezo actuator.

1 1. Valve according to Claim 8 or 9, characterized in that a rotary magnet or a lifting magnet or piezo actuator acts on the axis (57) or via a swivel arm.

12. Valve according to claim 10 or 1 1, characterized in that a capacitor is provided as a memory for the energy required for the closing movement.