DE3710699C1 - Hydraulic control device for a consumer group - Google Patents

Abstract

In such control devices, the monitoring valve switches off the supply controller at the pressure or stroke limit or it limits the effective volumetric flow. The monitoring valve does not tell whether the consumer has actually exceeded or fallen short of the pressure or stroke limit, because it responds independently of the operating direction of the consumer. The novel control device is to directionally monitor the consumers. To directionally monitor the consumers (V), the control line branch (34) is constantly attached via the relief control line (36, 37, 38) to the displacement control slide (S1 - S5) and in the interior of the same can be attached directly to the tank solely in a control position (a or b) in which the consumer has been loaded in a direction in which it exceeds a predetermined pressure or stroke limit in the group of consumers. Although the monitoring valve responds, the relieving or limiting function only comes to bear if the displacement control slide reaches a control position in which the consumer would move in a direction in which it exceeds the pressure or stroke limit. On account of the directional monitoring of the consumers, the control device is suitable, for example, for the simultaneous control of various operating cylinders and hydraulic motors in mobile cranes. <IMAGE>

Description

The invention relates to a hydraulic control device tion specified in the preamble of claim 1 a kind.

From a publication "load-dependent proportional veins tile PVG 60 HK.50 ", from Danfoss 1983, p. 22, lower picture, is a hydraulic control known device of this type, in which in the discharge Performance control line of each directional spool valve at least a monitoring valve is provided. The relief The control line runs directly from the control line branch to the tank. This leads to the disadvantage that everyone Consumers with regard to a pressure or stroke limit depending on which direction it is monitored is acted upon. The pressure from the discharge line completely when a pressure or stroke limit is reached dismantled, the consumer can no longer return be moved because the inlet regulator of the directional control valve remains switched off. Then there are additional measures required to move the consumer back to the Ignore monitor valve. Limits the monitor pressure relief valve, however, the pressure in the relief tax Instruction, stands for moving the consumer back only one according to the influence of the surveillance valve-reduced volume flow for route control Sliders are available, although the consumer specifies if necessary, to move back a larger volume flow would need. A directional one for every consumer and individual monitoring for both directions of movement  chung is in this hydraulic control device not possible.

In one known from DE-OS 26 56 059 hydrauli control device is the control line branch over a single relief control line directly with the Tank connected. In the relief control line is as Monitoring valve a pressure-controlled limitation valve included. The consumer becomes independent of monitors the direction in which it is applied, d. H. regardless of what tax position the tax is in slide is moved. This has the disadvantage that when a dangerous pressure limit is reached, the loading limit valve the pressure in the relief tax tion reduced or limited, and that the two-way ler, who serves as an inlet regulator to the directional control spool, only a limited or reduced amount of the way tax slider feeds to the consumer for renewed un to exceed the pressure limit.

In one known from DE-PS 30 22 592 hydrauli control device with a directional control slide for a double-acting hydraulic motor is one Discharge control line not directly to the tank but connected to the directional spool in such a way that this only then with the discharge control line connects the tank when it is in a tax position is moved in which the hydraulic motor has a load limit would be moved out. This has the advantage that the Hy draulic motor through the monitoring valve in the discharge Control line unaffected in the opposite direction can be moved in which the load limit un again steps. Because the relief control line the pressure holds for the inflow controller of the control device, if the control device by adding several Directional spool valve extended for additional consumers  would respond to the monitoring valve and discharge Most of the relief control line none of the others Directional spool work more.

The invention has for its object a hydraulic cal control device of the type mentioned create, in the case of several directional spool ver provided consumers with no mutual interference and depending on their direction of exposure are awake.

The object is achieved with the im characterizing part of claim 1 specified Features resolved.

With this training, despite the response of the supervisor valve when a pressure or stroke limit is reached a consumer the associated road tax slide only switched off when he is in a tax position is brought, a further movement of the Ver effect beyond the pressure or stroke limit would. That means that the consumer becomes directional monitored without affecting the utility the other consumers in the consumer group te, because of the one for each way tax slider responsible inlet controller who control the way slide switches off without the volume flow in the pump pen line to the other directional spool rivers. Will the directional control spool in which the over Watch valve has addressed, however, in a tax Instruction in which his consumer is in a the direction below the pressure limit or stroke limit is acted upon, the addressed is automatically Monitoring valve ignored because of the directional control Then not with the tank via the discharge control line connects. If the consumer is in both directions  should be monitored, and thereby for different Way, e.g. B. to different pressure limits or one pressure limit in one direction of movement and one Stroke limit in the other direction of movement, this is it easily achieved by two Relief control lines to the directional spool closed and in each of its two tax positions because one is relieved to the tank, and that in everyone Relief control line provided a monitoring valve hen and individually adjusted. The hydraulic Control device offers an increased in this way Security and is especially for mobile cranes or similar with several hydraulic motors and cylinders as Machines or facilities equipped for consumers expedient. The control device of the hydraulic control he device can be a constant pump Pressure source a 3-way controller or a control device for a pump that can be regulated with regard to the volume flow pe (control pump).

Another advantageous embodiment is given in An say 2. The monitoring valve is on 2/2-way valve, which is used by the consumer or with the Ver element that can be moved or influenced by it is actuated when a stroke limit (linear stroke or rotary hub) is reached.

In practice, the aforementioned monitoring can be done principle particularly useful according to claim 3 realisie Ren. Such proportional directional spool are from their constructive conception for the additional radio tion of the discharge of the discharge control line to Tank well suited.

The measures of claim 4 are expedient because the relief control lines are each relieved prematurely to act upon the respective consumer line, so that the directional control slide is immediately switched off without supplying the consumer with harmful pressure medium. The discharge control line is connected so that the spool of the directional spool makes the connection to the return channel on the connection with respect to the pump connection opposite the consumer connection, which would subsequently be connected to the pump connection to the consumer via the pressure or Actuate stroke limit beyond.

Embodiments of the inven subject of the explanation. It shows

Fig. 1 is a block diagram of a hy draulic control device for a group of consumers,

Fig. 2 shows a variant of Regelvor direction for the hydraulic control device according to FIG. 1, and

Fig. 3 shows a longitudinal section of a directional spool valve, as is appropriate for the hydraulic control device according to FIGS. 1 and 2.

A hydraulic control device 1 for a group of consumers V has a control device R ( FIG. 1) and five proportional directional control slides S 1 - S 5 , each with its own two-way inflow controller Z 1 - Z 5 . The consumers V are a double-acting cylinder 2 , a hydraulic motor 3 , a double-sided loading cylinder 4 , a double-acting cylinder 5 with stroke limitation and a double-acting cylinder 6 with stroke limitation. To load the consumer V is a common pressure medium source, here a constant pump 7 , vorgese hen. In a control device R of the volume flow is provided by the pump to the individual directional control valves S 1 - S regulated flows. 5 For this purpose, a 3-way controller 8 usual design is provided. From the pump 7 leads a pump line 9 on the one hand to the control device R and on the other hand to the inlet regulators Z 1 - Z 5 of the control slide S 1 - S 5 , which are connected in parallel to one another. A tank line 10 is connected via branch lines to the directional control valve S 1 - S 5 on the one hand and the Regelvor direction R on the other. The maximum system pressure is limited by an articulated, adjustable pressure relief valve 11 in the control device R. To the control device R also leads a main control line 12 , which is acted upon in a manner explained later from the directional control spools S 1 - S 5 with a consumer pressure-dependent control pressure and is used to control the 3-way controller 8 and to pilot the pressure relief valve 11 . An auxiliary control line 13 , which branches off from the pump line 9 and is guided over all directional spool valves S 1 - S 5 , ent holds a pressure reducing valve 54 , with which a certain pressure in the auxiliary control line 13 is maintained in the unpressurized pass.

The directional control valve S 1 - S 5 are designed identically in this embodiment, so that only the directional control valve S 1 is explained in detail (see also FIG. 3). The directional control valve S 1 contains a piston valve 14 , which is adjustable between a zero position with no pressure in order to run via the 3-way controller 8 in two control positions a and b . Lead from the housing of the directional control slider S 1 bers consumer lines 15, 16 to the two sides of the double-acting cylinder. 2 Furthermore, stub lines 17, 18 are arranged in the housing, which lie outside half of taps 19, 20 of the consumer lines 15, 16 . Flow paths 21, 22 and 23, 24 are formed in the slide piston. There are also connecting lines 25 and 28 and 26 and 27 . The taps 19, 20 and the connecting lines 26 and 27 are shown in FIG. 1 leading from the housing of the directional control valve S 1 . In practice, however, these are contained inside the directional control slide (see FIG. 3 and as will be explained later). The connecting lines 25 and 28 , which in the two control positions can be connected to the spur lines 17, 18 via the channels 21 and 24 and are shown as connected to the tank line 19 , also run inside the directional control valve S 1 .

The spool 14 is either by Druckvorsteu generation (control lines 29, 30 ) and a control 31 only schematically indicated from the control line 13 or by a hand lever 32 .

To the connecting lines 26, 27 of the taps 19, 20 , a control line branch 34 is connected, which leads via a throttle to the control side of the two-way inlet regulator Z 1 , the inlet regulator Z 1, on the other hand, from the part of the inlet regulator and the directional control valve S 1 Pump line 9 is pilot controlled. The control line branch 34 is connected to the main control line 12 via a spur line 33 and a check valve 35 blocking the directional control valve S 1 . A discharge control line 37 branches off from the control line branch 34 and is divided into two branches 36, 38 . In both branches 36, 38 , monitoring valves 39, 40 are included, in the present embodiment, for example, individually adjustable and pilot-controlled pressure relief valves from the relief control line 37 . The two branches 36, 38 are connected to the stub lines 17, 18 of the housing of the Wegesteuerschie bers S 1 . They are locked in the neutral position shown.

In the relief control line 37 of the second Wegesteu erschiebers S 2 a pilot operated from the relief control line 37, adjustable pressure relief valve 41 is also included as a monitoring valve 41st Downstream of the monitoring valve 41 , the discharge control line 37 opens directly into the tank 42 .

In the third directional control valve S 3 , the relief control line 37 is connected to the branch line 17 only via the branch 38 . Here is a monitoring valve 43, again a pre-from the relief control line 37 operated, adjustable pressure relief valve 43 seen before.

In the fourth directional control valve S 4 , the relief control line 37 is connected to the branch 36 and the branch line 18 via a monitoring valve 44 . The monitoring valve 44 is a 2/2-way valve which can be actuated by a stop 45 of the double-acting cylinder at a stroke limit of the same so that it gives up its shut-off position normally held by spring force and switches into a through position.

In the fifth Weegsteuerschieber S 5 , the Ent relief line 37 is connected via the branch 36 to the stub 18 . In the relief control line 37, 36 two monitoring valves 46, 47 are connected in series, namely a 2/2-way valve that can be actuated by the stop 45 as with the directional control valve S 4 , and a pressure control valve piloted from the relief control line 37 , adjustable pressure relief valve .

The hydraulic control device works as follows:

In the illustrated zero position of all directional control slides via S 1 - S 5 , the pressure medium flows in an unpressurized circulation via the 3-way controller 8 switching to the open position to the tank line 10 . If the directional control slide S 1 is adjusted to its control position a (by pressurizing it via the control line 29 ), the pressure medium flows from the pump line 9 to the consumer line 15 via the open inlet regulator Z 1 . The consumption line 16 is connected to the tank line 10 via the slide piston 14 . The piston rod extends to the right in FIG. 1. Via the tap 19 and the channel 22 and the connecting line 26 , the control line branch 34 is acted upon with control pressure. This control pressure, together with the pilot pressure from the pump line 9, controls the inlet regulator Z 1 with regard to the volume flow required for the cylinder 2 . The pressure in the control line branch 34 passes through the check valve 35 also in the main control line 12 , where it is used to control the 3-way controller 8 , which on the other hand is directly pilot-controlled from the pump line. The 3-way controller 8 provides at least the volume flow that the consumer 2 needs. The branch 38 of the relief control line 37, 38 is connected via the branch line 17 and the channel 21 to the connecting line 25 to the tank line 10 . The pressure relief valve 40 has not responded, so that the pressure in the relief control line 37 is maintained. The branch 36 is still blocked off from the tank line 10 .

Simultaneously with the actuation of the directional control slide S 1 , any other of the directional control slide S 2 - S 5 can be actuated in the same way. If one of the United consumers V the further directional spool valve S 2 - S 5 requires a larger volume flow, the pressure in the main control line 12 rises accordingly, so that the 3-way controller 8 provides a larger volume flow. The inflow controller Z 1 of the first directional control slide valve S 1 , however, regulates the volume flow for the consumer 2 assigned to it irrespective of the volume flow in the pump line.

As soon as a pressure limit is reached by the extension of the piston rod of the cylinder 2 , which represents a drive, and to which the monitoring valve 40 is set, the monitoring valve 40 responds and leaves the relief control line 37 via the branch 38 , the branch line 17 , the channel 21 and the tank line 10 from so much pressure medium that the inlet regulator Z 1 throttles the volume flow so far that the cylinder 2 can no longer extend. This pressure limit is maintained. If the directional control slide S 1 is then adjusted into its control position b , the piston rod of the cylinder 2 can be retracted since this direction of movement of the cylinder 2 is monitored by the other monitoring valve 39 , which has not spoken to. In this way, the pressure limit can be fallen below again and the piston rod of the cylinder 2 can be retracted accordingly. If, when the piston rod is retracted, a critical pressure limit is reached, the monitoring valve 39 responds and limits the pressure in the relief control line 37 so that the inlet regulator Z 1 in turn only provides a low volume flow that prevents the piston rod from being drawn in too far. Then the branch 36 is relieved via the stub 18 and the channel 24 to the tank line 10 . The work of the other consumers V is not affected by the above-mentioned functions, because the directional control valve S 1 acts independently of the other way control valves S 2 - S 5 through its inlet controller Z 1 . If the pressure in the control line branch 34 is limited or reduced in the manner mentioned above, this change in pressure is not communicated to the main control line 12 , since the check valve 35 then blocks.

The second directional control spool S 2 of the Hydraulikmo is tor 3 in both directions of movement by the monitoring Sven til 41 in the same pressure limit monitored so that the feed regulator Z 2 each throttles the volume flow when reaching the same pressure and the hydraulic motor 3 stops, as soon as the monitoring valve has responded 41 .

When the directional control valve S 3 , the cylinder 4 is monitored only in the extension direction of the piston rod by the monitoring valve 43 . If in the control position a of the directional control valve S 3 he reaches a dangerous pressure limit, the pressure medium passing through the monitoring valve 43 via the branch 38 , the branch line 17 and the spool 14 to the tank will be released. If the directional control spool S 3 is moved into its second control position b , the piston rod of the cylinder 4 is retracted without pressure monitoring.

In the fourth directional control valve S 4 , the piston rod of the cylinder 5 is moved out in the second control position b until the stop 45 actuates the monitoring valve 4 , so that the relief control line 37 is suddenly relieved to the tank line 10 via the branch 36 , the branch line 18 and the spool 14 becomes. The inlet regulator Z 4 switches off completely. The cylinder 5 no longer receives pressure medium, unless the directional control slide S 4 is moved into its first control position a , in which the piston rod of the cylinder 5 can be retracted.

In the fifth directional control valve S 5 , the piston rod of the cylinder is moved out in the second control circuit b until the stop 45 actuates the monitoring valve 46 . However, the pressure in the relief control line 37 is not reduced entirely, but only to the extent specified by the downstream pressure-limiting monitoring valve 47, specifically via the branch 36 , the branch line 18 and the spool 14 to the tank line 10 . An additional safety function is provided here because the piston rod of the cylinder 6 can be moved beyond the stroke limit, provided that the pressure in the relief control line 37 does not rise above a dangerous pressure limit (monitored by the pressure limit monitoring valve 47 ).

In the embodiment of FIG. 2, a Regelvor direction R 'is provided instead of the control device R of FIG. 1. It is a so-called re gel pump 7 ' which for larger volume flows, for. B. 120 l / min and more is used because then the pump promotion for the unpressurized circulation to a low pressure or low volume flow can be regulated. From the pump 7 ' leads the pump line 9 to the inlet regulators Z 1 - Z 5 . The tank line 10 leads back to the tank. The supplied from the taps of the directional spool valve S 1 - S 5 main control line 12 leads in the re regulating device R ' via a lowering brake (sieve with throttle sel) for the unpressurized circulation to a servo cylinder 52 which has a control slide 53 in a pump branching device 9 ' Operated. The control part of the pump 7 ' is actuated by a Stellzy cylinder 48 supplied from the pump line branch 9' in one direction and from a spring-loaded cylinder 49 in the other direction. The spring storage cylinder 49 is connected to the control slide 53 . With these components, the volume flow in the pump line 9 is controlled as a function of the required volume of the consumers. Between the pump line 9 and the tank line 10 a Druckbe limit valve 50 is also seen before to limit the system pressure. Furthermore, a Druckmin derventil 54 is connected to the pump line 9 , which regulates the control pressure in the control line 13 to a fixed pressure value (z. B. 35 bar). The control line 13 is used for the regulation of the regulating members 31 when the slide piston 14 is actuated by the directional control valve S 1 - S 5 . The control pump in the control device R ' is used for example for mobile cranes of larger types, in which volume flows over 120 l / min are used who, because for these cases the control pump operates with less loss than the constant pump 7 of FIG. 1.

In Fig. 3 the proportional directional control slide valve S 1 can be seen in its structure, which corresponds to the proportional directional control slide valve S 2 - S 5 . It has a housing 55 with a bore 56 for the slide piston 14 . End caps 57 and 58 contain springs 59 which define the zero position of the slide piston 14 and at the same time ensure that it is secured against rotation. On the end cap 58 , the operating lever 32 is mounted, which is connected via a coupling member 60 to the slide piston 14 a related party. In the end caps 58 and 57 , chambers are formed, in which the movement of the slide piston 14 can be controlled in a pressure-dependent manner via the control lines 29, 30 . The control element 31 is expediently attached to the housing 55 Ge.

The slide piston 14 has on both sides of a central sealing zone annular grooves 61 and 62 , which are recognized by control 63, 64 and 65, 66 of the adjacent sealing zones.

The pump connection P , which is connected to the pump line 9 , is provided centrally in the housing 55 . On the side of the pump connection P , consumer connections A and B are provided as circumferential grooves in the bore 56 , which are connected to the consumer lines 15 and 16 . Again axially offset to the United consumer connections A, B outflow connections R are provided as tap holes, which are connected to the tank line 10 and the connecting lines 25, 28 for the relief control line branches 36, 38 form. In the housing 55 , the spur lines 17, 18 are drilled to the bore 56 from a housing outside, the mouths of which are indicated by dashed lines. It can be seen that in the zero position of the slide piston 14, the mouths of the stub lines 17, 18 are a short distance behind the control edges 63 and 66 and are shut off from the sealing zones of the slide piston 14 present there. In the central region of the housing 55 , the two connecting lines 26, 27 of the taps can also be seen, which are connected together to the control line branch 34 (indicated by a bore).

According to the illustration of Fig. 1 17, the branch 38 is connected to the discharge line 37 and the stub 18 of the branch 36, that is, the branches are cross-connected, so that during connection of the pump port P to the branch line with the actuator port A of the branch 38 via the stub 17 is discharged, while with a connection of the pump connection P to the consumer connection B the branch 36 is relieved via the stub 18 to the tank line. The spool 14 can not only be adjusted in the control positions a and b to act on the cylinder 2 accordingly, but there are intermediate positions of the spool 14 possible, in which the flow rate to the consumer is proportional to the displacement of the spool 14 . It is in this way a very sensitive control of the movement of the cylinder 2 possible, the inflow controller Z 1 being controlled accordingly.

The particular advantage of the hydraulic Steuerervorrich device according to the embodiments of FIGS. 1 to 3 is that at the same time different consumer maximum pressures are limited, and consumers can be driven at a higher pressure level because the speaking of a monitoring valve has no influence on simultaneously driven Has consumers with higher or never lower pressure with regard to the volume flow or the pressure. The same applies to the stroke limitation, which individually influences only the consumer monitored or even only the monitored direction of movement of the consumer and does not influence the work of the other consumers with regard to volume flow and pressure. Furthermore, it would be conceivable to connect a relief control line to the main control line 12 and to lead via a spur line 17 and 18 of the directional control valve S 1 - S 5 and also to use a 2/2-way solenoid valve in the discharge control line a pressure transmitter is controlled, which taps the pressure in any consumer line of a consumer. If the consumers of the directional control valve connected to the relief line were then acted on and the load moment could be exceeded, the 3-way controller between the pump and the tank line is switched off via the relief control line, so that none of the consumers can work as long as it is not moved in a direction reducing the load moment. In this way, all inlet controllers of the directional control valve would be bypassed and acted directly on the 3-way controller of the constant pump or, in the case of a control pump, on its control circuit. Here too, the possibility of connecting the relief control line directly to the return via the spool of its directional control valve could be used to advantage.

Claims (4)

1. Hydraulic control device for a consumer group, with at least two from a common pressure source ( 7, 7 ' ) supplied, via a pump and a tank line ( 9, 10 ) connected in parallel slide control (S 1 - S 5 ) for each at least one consumer (V) , with an upstream control device (R, R ') for the volume flow in the pump line ( 9 ), each with a directional control slide associated control line branch ( 34 ) between taps ( 26, 27 ) of each consumer line pressurized with pump pressure ( 15, 16 ) in the directional control slide valve and a control side of a 2/2-way controller (Z 1 - Z 5 ) connected upstream of the directional control slide valve and piloted from the pump line ( 9 ), with one via check valves ( 35 ) the control line branches ( 34 ) connected main control line ( 12 ) for the control device (R, R ') and with at least one of the provided two-way controller (Z 1 - Z 5 ) assigned Ent Lastungs-Steuerlei device ( 36, 37, 38 ) to the tank, which is connected to the control line branch and in which for maximum pressure or path monitoring of at least one consumer (V) at least one monitoring valve ( 39-44, 46, 47 ) is arranged with which the pressure in the control line branch ( 34 ) can be relieved or limited when a pressure limit or a travel limit is reached, characterized in that the control line branch (S 1 - S 5 ) to be assigned to the control line branch ( 34 ) in one direction monitored consumers (V , 3 ; V , 4 ; V , 6 ) via a relief control line ( 37, 36, 38 ) and, in the case of a consumer (V , 2 ) monitored in both directions, via two parallel relief control lines ( 37, 36; 37, 38 ) to the directional control spool (S 1 - S 5 ) is connected, and that the relief control line in the control circuit (a or b) of the directional control slide (S 1 - S 5 ) in this can be connected to the tank in which the consumer supplied by the directional control slide is acted upon in the monitored direction. 2. Hydraulic control device according to claim 1, characterized in that the monitoring valve ( 44, 46 ) is a ver against spring force from a locking position adjustable depending on the consumer stroke 2/2-way valve. 3. Hydraulic control device according to at least one of claims 1 and 2, characterized in that each directional control slide (S 1 - S 5 ) a proportional directional control slide with one in a bore ( 56 ) of its housing ( 55 ) from a zero position in two Control positions (a, b) adjustable spool ( 14 ) is that in the bore ( 56 ), starting from a central pump inlet (P) , axially offset each one consumer connection (A , B) , and a return connection (R 25 , 28 ) are arranged that the slide piston ( 14 ) cut a central Dichtab and on both sides of which has a circumferential groove ( 61, 62 ) to which sealing edges ( 63, 66 ) are connected outside sealing zones, and that in the Ge housing ( 55 ) two relief control line stub lines ( 17, 18 ) leading from the outside into the bore ( 56 ) are provided, the openings of which in the bore wall are offset in the circumferential direction to the return connections (R 25, 28 ) in axial B. Reach the bore, which are covered by the outer sealing zones in the zero position of the spool ( 14 ). 4. Hydraulic control device according to claim 3, characterized in that the mouths - in the zero position of the spool ( 14 ) - are adjacent to the control edges ( 63, 66 ), such that each control edge of one of the mouths of the relief control line stubs ( 17, 18 ) leading to the connection of the pump connection (P) with the one consumer connection (A, B) with the return connection (R 25, 28 ) assigned to the other consumer connection (B, A) .