EP1706649B1 - Hydraulic controller arrangement - Google Patents

Abstract

What is disclosed is a hydraulic controller arrangement for the pressure medium supply of a hydraulic consumer, e.g., of the rotating gear of a mobile work machine. At low pressure medium flow rates, the pressure medium flow rate draining from the consumer is backed up by means of a drain backup valve having the form of a pressure limiting valve and throttled accordingly, so that a back pressure is generated which is capable of preventing an advance of the mass actuated by the hydraulic consumer.

Description

The invention relates to a hydraulic control arrangement according to the preamble of patent claim 1.

Such hydraulic control arrangements, in which a pump is set in response to the highest load pressure of each actuated hydraulic consumers so that the pump pressure is a predetermined pressure difference above the highest load pressure, are also referred to as LS systems. The basic principle of such LS controls is, for example, in DE 199 04 616 A1 described by the applicant, so that these explanations are dispensable.

In particular, in applications in which large masses are to be moved in a horizontal plane via the hydraulic consumers, such as in a slewing drive of a mobile implement, high pressures occur during acceleration due to the inertia, which, however, when the mass is in motion, ie, for example, when the slewing has reached its desired rotational speed, quickly decrease. It can briefly lead to the advance of the mass, for example, if the friction of the mass on the ground on which it is moved is very low. This advance of the mass is accompanied by an unwanted change in speed. In the case of hydraulic drives with a regulated flow rate (LS control), this leads to a pressure drop in the supply line and to the braking of the mass, so that it has to be accelerated again to the desired level To reach speed. Consequently, the movement of the mass is subject to vibrations because of the recurrent acceleration pressure.

It is known that by a return-side, throttling the pressure medium flow rate, a back pressure can be generated, which prevents the advance of the mass and thus provides the desired stability of the controller. This throttling is usually realized in that a flow control groove adapted to the inlet control groove generates a back pressure which can vary depending on the pressure medium volume flow.

The problem is that with a very low pressure medium flow, the vote of the flow cross-section of the inlet cross-section is difficult to produce because of the very small opening cross-sections, so that it can come at low speeds again to the vibrations mentioned above.

In contrast, the invention has for its object to provide a hydraulic control arrangement, with a vibration-free control of consumers is made possible even at low pressure medium flow rates.

This object is achieved by a hydraulic Steueranordung with the features of claim 1.

According to the invention, a drainage valve is arranged in the course of a hydraulic consumer, via which a branch line leading to the tank upstream or upstream of the flow cross-section can be opened. D. h., In a first stroke range of a spool of a Directional valve of the hydraulic control arrangement, the returning pressure medium is not passed through a Ablaufsteuernut the spool but via the controlled by the drainage valve cross-section, which takes over the throttling of the return flow. The drainage valve can be very easily adapted to the low pressure medium flow rates, so that the control of the consumer at low speeds vibration-free is possible.

In a particularly preferred variant, a blocking device or the like is provided downstream or upstream of the drainage dam, via which the drain branch line can be shut off during a predetermined stroke of the spool valve of the directional control valve. This ensures that, for example, in the closed position of the spool valve or during an initial stroke, the drainage valve can open the outlet cross-section, so that the control of the consumer takes place solely via the cross-sections opened or closed by the spool valve.

In a particularly compact embodiment, this locking device is integrated to shut off the drain branch line in the directional control valve and formed by a control edge of the spool this way valve.

The structure of the control arrangement can be further simplified, although the backup valve and the drain branch line in the directional control valve, preferably in the control slide are integrated.

In a particularly simple embodiment, the drainage damper is by a formed by a spring against a valve seat biased closing body, for example, a ball.

In the known solutions, the load pressure is tapped at the associated load via a load reporting channel, which passes through an end portion of the spool. In such constructions, it is advantageous if this load signaling channel and a part of the flow branch line extending in the control slide are arranged offset in parallel and laterally to the valve axis in the control slide.

As an alternative to this solution, a sleeve can also be used in the control slide, in the axis of which the drain branch line runs, while the load signaling channel is formed by one or more longitudinal grooves provided on the outer circumference of the sleeve.

For dual-acting consumers, a drain valve can be assigned to each working port of the directional control valve.

Other advantageous developments of the invention are the subject of further subclaims.

• Figur 1 einen Längsschnitt durch ein erstes Ausführungsbeispiel eines proportional verstellbaren Wegeventils mit Ablaufstauventil für eine LS-Steueranordnung;
• Figur 2 einen Längsschnitt entsprechend Figur 1 mit einem gegenüber Figur 1 um 90° gedrehten Steuerschieber des Wegeventils;
• Figur 3 ein Schaltsymbol des Wegeventils aus Figur 1 und
• Figur 4 eine Teilansicht eines Wegeventils eines weiteren Ausführungsbeispiels einer hydraulischen Steueranordnung.

In the following preferred embodiments of the invention will be explained in more detail with reference to schematic drawings. Show it:

• 1 shows a longitudinal section through a first embodiment of a proportionally adjustable directional control valve with drainage valve for a LS control arrangement;
• Figure 2 is a longitudinal section corresponding to Figure 1 with a comparison with Figure 1 rotated by 90 ° spool valve of the directional control valve;
• Figure 3 is a switching symbol of the directional control valve of Figure 1 and
• Figure 4 is a partial view of a directional control valve of another embodiment of a hydraulic control arrangement.

FIG. 1 shows a longitudinal section through a continuously adjustable directional control valve 1 of an LS control arrangement. About this directional control valve 1, a metering orifice is formed on the one hand, via which the pressure medium flow rate is set to the consumer. Furthermore, this directional valve determines the direction of the pressure fluid flow to and from the consumer and thus the direction of movement. The metering orifice is preceded or followed by an individual pressure compensator, whereby in the case of downstream pressure compensators one speaks of a LUDV system and, in the case of upstream pressure compensators, a conventional LS system which does not allow any load pressure-independent flow distribution (LUDV). The LUDV control represents a special case of an LS control. As will be explained in more detail below, the pressure medium flowing from the consumer is throttled at low pressure medium volume flows via a drainage damper 57, 86 in order to prevent pressure fluctuations.

The directional control valve 1 shown in Figure 1 is received in a valve disc 2 of a valve block of a mobile implement, such as an excavator. The valve disc 2 has a valve bore 4, in which a spool 6 is biased via not shown, the front side engaging valve springs in a neutral position. On the valve disc 2, a pressure port P, two working ports A, B, a tank port T and a LS port LS are formed. The valve bore 4 is radial to annular spaces (from left extended to the right in Figure 1) 8, 10, 12, 14, 16, 18, 20 and 22, wherein the annular spaces 8, 10, 12 control oil chambers, the two annular spaces 14, 20 tank spaces, the annulus 18 a pressure chamber and the space 16th a consumer space and the space 20 should also be a consumer space, the LS connection (control oil chambers 8, 10, 12) the tank connection (tank spaces 14, 22), the working ports A, B (discharge space 16, flow space 20) and the pressure port P Are assigned (pressure chamber 18).

The control slide 6 has axially spaced control grooves, through which two control collars 24, 26 formed in the central region, two end guide collars 28, 30 and a tank collar 32 are formed.

At the mutually facing annular end faces of the control collars 24, 26 control edges 34, 36 are formed, which are each designed with fine control notches 38. About these control edges 34, 36, the connection of P to A or P to B can be controlled in the axial displacement of the spool 6. In the illustrated neutral position of the spool this connection is shut off.

At the respective outer annular end faces of the control collars 24, 26 tank control edges 40, 42 are provided, which are also provided with fine control notches 44 (see Figure 2). In the illustrated neutral position, the connection from T to A or from T to B is shut off by the tank control edges 40, 42.

The tank collar 32 has an LS control edge 46, via which the connection from the tank space 14 to the control oil chamber 12 up and is zuusteuerbar. In the illustrated neutral position, this connection is open.

In the right in Figure 1 end portion of the spool 6 an axial bore 48 is frontally introduced which is closed off by a screw plug 50. This axial bore 48 is downgraded to a valve seat 52, against which a ball 56 is biased by a spring 54. Through this, the connection between a transverse bore 58 and a transverse bore 60 shut off, in which the axial bore 48 opens. The transverse bore 60 in turn opens into control grooves 62 formed on the outer circumference of the control collar 24. In the illustrated neutral position, these block the connection between the tank space 22 and the supply space 20, being open towards the tank space 22, so that the ball 54 is on all sides with tank pressure acted upon and biased against its valve seat 52.

The biased against the valve seat 52 ball 54 forms a drainage valve 57, via which - as will be explained in more detail below - after a small displacement of the spool 6, a flow cross-section to the tank T is aufsteuerbar.

In the control collars 24, 26 these radial radial LS-radial bores 66, 68 are formed, which open into an axially extending LS channel 70, which is designed as a blind hole and ends in the LS radial bores 68. The LS channel 70 is extended to the left to a receiving bore into which a sleeve 72 is inserted.

The sleeve 72 is provided at its top and bottom in FIG. 2 peripheral region each with a longitudinal groove 74, which extends up to a ring groove 75, towards which an LS bore 76 of the spool 6 open is. On the right in Figure 1 end face of the sleeve 72 a recess 73 and end recesses 77 are formed, via which the longitudinal grooves 74 are connected to the LS channel 70, so that upon displacement of the spool 6 from the neutral position shown in the consumer space 16 and Load pressure applied in the consumer space 20 can be reported via the LS radial bores 66 or 68, the LS channel 70, the longitudinal grooves 74 and the LS bore 76 into the control oil chamber 10, which is connected to the LS port.

The sleeve 72 is closed at the front by a screw plug 79 and fixed in the bore 78 in the axial direction.

In the sleeve 72 is - as in the right end portion of the spool 6, an axially extending bore 78 is provided, which is downgraded to the right to a valve seat 80, against which a ball 82 is biased by a spring 84. The ball 82 biased against the valve seat 80 forms a second drainage damper 86. The closure screw 79 supports the spring 84 with a projection projecting into the bore 78.

The spring 84 receiving part of the bore 78 is connected via a the spool 6 and the sleeve 72 passing through the transverse channel 88 with the tank space 14. The beyond the valve seat 80 arranged, radially recessed portion of the bore 78 is connected via a transverse bore 90, radial bores 91 in the spool and the outer periphery of the spool 6 arranged cam grooves 92 with the tank space 14 (neutral position) or the consumer space 16. The control grooves 92 can control the connection from the pre-pressure chamber 16 to the drainage valve 86.

FIG. 3 shows the hydraulic circuit symbol of the directional control valve 1 explained with reference to FIG. In its spring-biased home position, the working ports A, B are shut off from the pressure port P and the tank port T. With a displacement of the spool 6 to the left from the illustrated neutral position, the connection of the pressure port P to the working port A can be controlled - the connected to the port A pressure chamber of the consumer is supplied with pressure medium. The running of the consumer pressure medium is first returned to the tank port T at a low axial displacement of the spool 6 via the working port B and 56 against the force of the spring drainage valve 57, so that the returning from the consumer pressure fluid is throttled over this drainage damper 57, so that a leading of the mass moved by the consumer is prevented and a vibration-free control of the consumer is ensured.

In a further axial displacement of the spool 6 to the left, the throttling of the return flow through a flow control edge of the directional control valve 1 - at an axial displacement to the left this flow control edge is formed by the tank control edge 40, via which the connection from B to T is turned on.

Accordingly throttles first with a displacement of the spool 6 to the right, the drain valve 86, the pressure fluid flow, after a further axial displacement of the spool to the right in Figures 1 and 2, the throttling of the return flow through the tank control edge 42 of the control collar 26, via which the connection from port A to port T is opened.

For a better understanding, these pressure medium flows are explained again with reference to FIGS. 1 and 2.

In the neutral position, the working ports A, B are shut off from the pressure port P and the tank port T. The drainage damper valves 57, 86 are acted upon in the opening direction with the tank pressure and are pressed by the force of the spring against the valve seat 52, 80.

When moving the spool 6 to the right, the connection from P to B is initially controlled via the fine control notches 38 (metering orifice) so that the consumer is supplied with pressure medium via the working port B. After an initial stroke of the spool valve 6, the cam 92 is opened to the consumer space 16 and closed to the tank space 14 toward, so that the drainage valve 86 in the opening direction of the pressure in the pressure medium return, d. H. in the consumer space 16 is acted upon. The drain accumulation valve 86 opens when the pressure in the consumer chamber 16 has reached the pressure equivalent of the spring 84 (for example, 15 bar) - the pressure medium flow running off the consumer is correspondingly accumulated and the amount of pressure medium flowing is throttled. When the drainage valve 86 is open, the pressure medium flows via the flow cross section opened by the control groove 92 and the opened drain control valve 86 from the consumer compartment 16 into the tank space 14 and from there to the tank connection T.

As mentioned above, the control groove 92 controls the connection to the drain poppet valve 86 only after one certain hub, so that in the neutral position of the directional control valve 1 is an automatic set in motion of the consumer is prevented. This could be done, for example, when an excavator is parked on a slope and the slewing due to its own weight trying to turn down, downhill.

In a further displacement of the valve spool 2, the metering orifice is further opened and increased according to the pressure medium flow rate and thus the speed of the consumer. After a further opening of the connection to the drainage valve 86, the connection from the consumer compartment 16 into the tank space 14 is controlled via the fine control notches 44 of the tank control edge 42, so that the flow-controlled through the tank control edge 42 drain cross section now takes over the throttling of the running pressure medium quantity. The drain accumulation valve 86 remains open.

The load pressure at the load is reported via the LS radial bore, the LS channel, the front recess 77, the recess 73, the longitudinal grooves 74, the ring base 75 and the LS bore 76 in the control oil chamber 10.

When shifting back the spool 1 is first controlled by the control edge 42 of the flow cross-section, whereupon the drain throttling is carried out in the manner described above by the damming of the draining pressure medium through the drain accumulation valve 86. After another partial stroke, the control groove 92 controls its connection to the consumer space 16, wherein the control groove 92 opens to the tank space 14 and corresponding tank pressure is applied to the drainage valve 86, so that this is moved back into its closed position.

In an axial displacement of the spool 6 from the neutral position in Figure 1 to the left, the connection from the pressure chamber 18 to the discharge chamber 16 is opened, d. H. the metering orifice is then determined by the inlet opening of the control edge 34. The pressure medium flow from the consumer is determined after a small initial stroke, in the manner described above, first by the action of the drainage valve 57 and after the further partial stroke by the controlled via the control edge 40 and the associated Feinsteuerkerben 44 drain cross section.

In the above-described variant, the drainage accumulation valve 86 is integrated into the sleeve 72 inserted into the control slide 6 and the LS channel 70 is designed to escape.

4 shows a variant is shown, in which the LS channel 70 is formed by a parallel offset to the spool bore bore, which is closed at the end by a screw plug 96. In the parallel distance to the bore 78 is arranged with the valve seat 80 for the ball 82 of the drainage valve 86 in the end portion of the spool 6. The bore 78 is closed by a screw plug 98 frontally. The bore 80 is then connected via an angular channel 100 with the circumferential cam groove 62. Incidentally, the spool 6 of FIG. 4 substantially corresponds to that of FIGS. 1 and 2.

The embodiment shown in Figure 4 has a somewhat simpler device construction, but is somewhat complex to perform in manufacturing, since the introduction of the offset holes and the angular channel 100 is more difficult to perform than at the solution in which the channel guide is substantially integrated into the sleeve 72.

Disclosed is a hydraulic control arrangement for supplying pressure medium to a hydraulic consumer, for example the slewing gear of a mobile working machine. At low pressure medium flow rates of the running from the consumer pressure fluid flow is accumulated by means of a drain valve designed as a pressure relief valve and throttled accordingly, so that a back pressure is generated, which can prevent a lead of the mass actuated by the hydraulic consumer.

LIST OF REFERENCE NUMBERS

1

way valve

2

valve disc

4

valve bore

6

spool

8th

Control oil chamber

10

Control oil chamber

12

Control oil chamber

14

tankage

16

consumer space

18

pressure chamber

20

consumer space

22

tankage

24

control collar

26

control collar

28

guide collar

30

guide collar

32

tank Bund

34

control edge

36

control edge

38

Fine control edge

40

Tank control edge

42

Tank control edge

44

Fine control notch

46

LS control edge

48

axial bore

50

Screw

52

valve seat

54

Bullet

56

feather

57

Drain backup valve

58

Radial bore star

60

bore star

62

control groove

64

Throttle control edge

66

LS-radial bore

68

LS-radial bore

70

LS-channel

72

shell

73

recess

74

longitudinal groove

75

ring groove

76

LS-bore

77

front recess

78

drilling

79

Screw

80

valve seat

82

Bullet

84

feather

86

Drain backup valve

88

Querkanal

90

bore star

92

control groove

96

Screw

98

Screw

100

angle channel

Claims (9)

1. Hydraulic controller arrangement for the pressure medium supply of a hydraulic consumer whereby a load having a high mass may be moved, comprising a pump which may be controlled in dependence on the load pressure at the consumer and whereby pressure medium may be conducted via a proportionally adjustable directional control valve (1) to the consumer and from the latter via a drain cross-section controlled open by a drain control edge (40, 42) of the directional control valve (2) to a tank passage (T), characterized in that in the pressure medium flow path between the consumer and the tank passage (T) a drain backup valve (57, 86) is arranged, whereby it is possible to open a drain branch line (62, 60, 52, 58; 92, 90, 80, 88) leading to the tank passage substantially prior to opening of the drain cross-section.
2. Hydraulic controller arrangement in accordance with claim 1, wherein shut-off means (94) for blocking the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) during a predetermined stroke of a regulator (6) of the directional control valve (1) are provided in the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) upstream or downstream from the drain backup valve (57, 86).
3. The control arrangement in accordance with claim 2, wherein the shut-off means (94) are formed by a control edge (64, 94) of the regulator (6).
4. The control arrangement in accordance with any one of the preceding claims, wherein the drain backup valve (57, 86) and the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) are integrated into a regulator (6) of the directional control valve (1).
5. The control arrangement in accordance with claim 3 and 4, wherein the control edge (64, 94) is formed by a control groove (62, 92) into which a radial bore (60, 90) of the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) merges.
6. The control arrangement in accordance with any one of claims 2 to 5, wherein the drain backup valve (57, 86) is a pressure limiting valve comprising a valve body (54, 82) that is biased against a valve seat (52, 80).
7. The control arrangement in accordance with any one of claims 4 to 6, wherein the drain backup valve (57, 86) is arranged in a sleeve (72) inserted into the regulator (6), at the outer periphery of which a load reporting passage (74) extends which is formed in portions thereof by a longitudinal groove.
8. The control arrangement in accordance with any one of claims 4 to 6, wherein the drain backup valve (57, 86) is arranged in a portion (78) of the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) extending in parallel with a load reporting passage (70), with the portion (78) of the drain branch line (62, 60, 52, 58; 92, 90, 80, 88) and/or the load reporting passage (70) extending at a parallel spacing from the regulator axis.
9. The control arrangement in accordance with any one of the preceding claims, wherein the directional control valve (1) has two work ports A, B, and to each work port one drain backup valve (57, 86) is associated.

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