DE3813020C2 - Device for controlling the feed of a hydraulic actuating device - Google Patents

Description

The invention relates to a device for Feed control of a hydraulic actuator in opposite directions and different Feed speeds in the preamble of claim 1 defined genus.

In a known device of this type (DE 34 22 978 A1) has the pilot operated proportional directional control valve, which in generally from one of a proportional magnet actuated pilot valve and one of the latter controlled main control valve, there are a total of four controlled work connections, which of the four controlled working connections of the main control valve be formed. The spool of the main control valve, that with an uncontrolled proportional directional control valve in one  spring-centered middle position can be held over the Pilot valve in a first spool position on the one side of the middle position and in a second Spool position on the other side of his Middle position. The directions of movement of the Working pistons in the working cylinder are in the first and second spool position opposite to each other. Each after that set by the spool Throttle cross section of the orifice plate can be in any Control spool position different Feed speeds of the working piston can be achieved. Generally there are two in each spool position Feed speeds, namely rapid forward (EV) and Work feed forward (AV) in the first Control spool position and rapid traverse backward (ER) and Backward feed (AR) in the second Control spool position, possible, the switchover from EV to AV and from AR to ER depending on the position of the Extending or retracting piston rod of the working cylinder he follows.

The volume flow to and from the working cylinder regulating pressure compensator ensures in connection with the device for specifying a counter pressure for the working piston in the piston rod chamber for one of load and Pressure fluctuations independent constant feed rate, the pressure compensator at AV as primary or Inlet pressure compensator in the inlet flow to the working cylinder and at AR as a secondary or discharge pressure compensator in the discharge flow from Working cylinder works. In the sequential circuit, the Pressure compensator in connection with the throttling effect of the Orifice plate still the counter function for the working piston, by creating a certain back pressure in the piston chamber maintained during the retraction movement of the piston. The Device for specifying a counter pressure in the  Piston rod chamber is controllable Pressure relief valve and the pressure compensator is as 2-way valve with 4/2-way solenoid valve for switching the Pressure balance from primary to secondary arrangement and vice versa educated.

For the EV of the working piston in the first Control spool position and for the ER of the working piston in the second spool position is to bypass the Pressure relief valve each a check valve required, with a check valve between the Piston rod chamber and the pressure source and a Check valve between the piston rod chamber and the fourth working connection of the proportional directional valve is arranged. The flow direction of the former Check valve is from the piston rod chamber to the Pressure source and that of the second mentioned check valve from the fourth working connection of the proportional directional control valve directed to the piston rod chamber. The ratio of Piston area of the working piston is at least 1.5: 1, the larger piston area the piston chamber and the smaller piston area limits the piston rod chamber, and enables a so-called plunger switching, in which the pressure oil pushed out by the working piston at EV immediately the print page, e.g. B. the pressure source is fed.

The object of the invention is in a device for Feed control of a hydraulic actuator for opposite directions and different Feed speeds by means of proportional directional control valve, Pressure compensator and counter-pressure device the device effort to be kept as low as possible and also loss-making Reduce oil flows.

Starting from a generic device for Feed control does this task through the characterizing features of claim 1 solved.

The inventive device for feed control hydraulic actuator with the characteristic Features of claim 1 has the advantage that by the new created fifth work connection in Proportional directional control valve and the additional third Control spool position for rapid forward (EV) die Bypassing the counter pressure device via the  Proportional directional control valve is controlled and thus the two Check valves saved in the known device will. The well-known 4 / 3- Proportional directional control valve, as in DE 28 40 831 C2 or in the reference "Bosch Hydraulics, Proportional valves, hydraulics in theory and practice 1983, Robert Bosch GmbH, Business Unit K 6 Hydraulics ", is only slightly modified by the Connection between the outer two ring channels, from those connected to a work connection stands, locked and a hole to the other ring channel which is led to the additional fifth work connection forms. The latter ring channel is additionally in its axial width increases and the Pressure tap holes in the spool and in the housing of the Proportional directional control valve for controlling the two Control connections are changed. This can be done without too much great design effort on the proven 4/3 proportional directional control valve can be used. Through the Assignment of the outermost spool position to the Fast forward (EV), the control spool runs over the first spool position for the work thrust forward (AV) before it triggers EV. This will make it a smooth extension of the working piston with low speed increase too achieved in rapid traverse. It also peaks in speed avoided in the reverse case, i.e. when arranging the third spool position immediately next to the Middle position when switching back from AV to Center position as a result of passing the EV position would.

Further advantages of the device according to the invention result by the fact that in the third spool position for the urgent process (EV) the fourth work connection, which with the Counter pressure device is connected,  is completed. This will be the case with plunger operation in rapid forward (EV) from the piston rod area of the Working oil flowing back to the working cylinder immediately Piston chamber fed. With a variety of Feed units z. B. in transfer streets so that oil flow to be supplied to the hydraulic pump considerably be made smaller. In the known known at the beginning Device, however, flows in the EV through the usual Adjustment pressures already open in the EV pressure relief valve part of the pressure oil from the piston rod chamber of the Working cylinder on the fourth working connection to Relief chamber or oil tank instead of the piston chamber of the Working cylinder. This oil flow flowing to the tank must can also be supplied by the hydraulic pump. By preventing an oil flow through the Pressure relief valve in the EV also becomes the loss line eliminated by the high temperature in the case of Flow through the pressure relief valve in the EV due to the relatively high pressure drop arises there. Overall, the device according to the invention enables Reduction of the electrical to be installed Drive power, the pump flow or the Storage size and the cooling capacity. This means - especially with a larger number of feed drives in a machine, e.g. B. Transfer street - a smaller one Electric motor to drive the feed pump, a smaller one Feed pump and / or a smaller memory and one smaller oil cooler or its elimination.

By the measures listed in the other claims are advantageous developments and improvements in Claim 1 specified device for feed control possible.

An advantageous embodiment of the invention results from claim 2. The feedback of the from the  Piston rod chamber of the working cylinder Plunger operation (rapid traverse forward EV) flowing out Pressure oil takes place in this embodiment according to the Pressure compensator. This will flow through the Pressure compensator smaller than in the known device. At Working cylinders with a piston area ratio of 2: 1 the flow rate through the pressure compensator is only that Half. This can be done in a smaller nominal size be carried out. The device only has three Components on, namely the piloted Proportional directional valve, the controllable pressure control valve and the counter pressure device, which preferably as controllable pressure relief valve is executed. These few components enable the device to be designed as a control block with the smallest possible control block volume.

An advantageous embodiment of the invention results also from claim 3. In the first spool position is a constant work feed forward (AV) if preserved the full function of the pressure compensator and Counter pressure device possible.

An advantageous embodiment of the invention results also from claim 4. In the second spool position is the orifice depending on the throttle cross-section through the rapid reverse control spool (ER) and Work feed backwards (AR) possible, with the between the second and third work connection switched on Throttle counter-holding function takes over.

An advantageous embodiment of the invention results also from claim 5. In this embodiment, the Pressure balance between proportional directional valve and Working cylinder arranged. Smaller thanks to a 4/2-way valve The nominal size is the pressure compensator at the advance of the working piston  in feed control and in return of the working piston in Sequence control switched. The pressure compensator takes over when moving the working piston into the working cylinder at the same time the function of the counter pressure device in large nominal size.

An advantageous embodiment of the invention results also from claim 8. Again, the pressure compensator is between the proportional directional control valve and the working cylinder arranged, but the 4/2-way valve for Switching the pressure compensator. This is achieved through the Control spool of the proportional directional valve causes. The Arrangement of the pressure tapping holes in the housing results automatically when the working piston moves forward and backward required assignment of the differential pressures at the orifice plate to the corresponding control inputs of the pressure compensator. In order to only three components are needed here, too of the smallest possible control block are interconnectable.

A particularly advantageous embodiment of the invention also results from claim 13. By the arrangement of the Pressure balance between the fourth valve connection and the Piston rod chamber becomes the counter-holding function of the Counter pressure device when extending the piston rod from the pressure compensator. This eliminates the Counter pressure device and the entire device consists of only two components. The connection hole pattern of the proportional directional control valve and thus the overall device is a standardized directional valve connection hole pattern, whereby a Line connection via a conventional connection plate is possible.

The pressure compensator is only forward and at work flows backwards. This results in that Pressure compensator only a small nominal size. Fast forward (EV) becomes the non spring loaded control input of the  Pressure compensator pressurized and the other control input relieved. This closes the pressure compensator in the EV. At AV start regulates the pressure compensator from the closed to the open state, d. H. there is no start jump.

For the piston return, there is one for the rapid traverse fourth control spool position provided. In rapid traverse backwards (ER) the pressure compensator is also closed. When changing from ER to work feed backwards AR becomes the pressure compensator turned on, so that here too Approach jump occurs at AR start. The counterforce at AR results from the pressure drop in the between the second and third work connection of the Throttle proportional switch on.

With AV, the pressure compensator acts as a secondary or Discharge pressure compensator and with AR as primary or Inlet pressure balance. The control edge geometry of the Control spool of the proportional directional valve guaranteed thereby that in each case the one established at the measuring throttle Pressure difference in correct assignment at the control inputs the pressure compensator lies.

An advantageous embodiment of the invention results also from claim 18. These measures consist in the Middle position of the proportional directional control valve a connection between the pressure source and the non spring loaded Control input of the pressure compensator. So that is the pressure compensator closed. At the beginning of the feed movement forward or backwards opens the pressure compensator. The work feed thus starts without a jump.

An advantageous embodiment of the invention results also from claim 19. Through these connections the specified work connections will creep away the  Working piston in the middle position of the spool uncontrolled proportional directional control valve avoided.

drawing

The invention is illustrated in the drawing Exemplary embodiments in the description below explained in more detail. Show it:

Fig. 1, 3 and 5 are each a circuit diagram of a device for feed control of a hydraulic actuating device according to a first, second and third embodiment,

Fig. 2, 4 and 6 are each a side view of a proportional directional control valve of the apparatus of Fig. 1, 3 and 5, partially in section,

Fig. 7 is a circuit diagram of a device for feed control of a hydraulic actuating device according to a fourth embodiment,

Fig. 8 is a side view of the device in Fig. 7, partially sectioned.

Description of the embodiments

The device shown in the circuit diagram in FIG. 1 serves to control the feed of a hydraulic actuating device in opposite directions with different feed speeds. The hydraulic actuating device has a double-acting working cylinder 10 with a working piston 11 axially displaceable therein. The working piston 11 defines a first piston surface 11 a, a piston chamber 12 and an opposite second piston surface 11 b, a rod chamber 13, from which a fixedly connected to the working piston 11 piston rod Removing 48 through advancement of the working piston 11 in opposite directions and can be inserted. The piston area 11 a is larger than the piston area 11 b, the ratio of the piston areas 11 a to 11 b being at least 1.5: 1, so that so-called plunger operation is possible in which the pressure ejected from the piston rod chamber 13 - Or control oil is supplied directly to the piston chamber 12 .

The device for feed control of the hydraulic actuating device has a proportional directional control valve 14 in a pilot-controlled design. It consists of a pilot valve 15 , which is actuated by a proportional magnet 16 , and a main control valve 17 with a hydraulically operated control slide 18 , which is spring-centered in its neutral central position 0 . The structure and mode of operation of the pilot valve 15 with proportional solenoids 16 in connection with a main control valve 17, which is however designed as a 4/3-way valve there, is described in DE 28 40 831 C2. Both the pilot valve 15 and the main control valve 17 is a position transducer 19 or 20 is provided, which senses the stroke of the pilot spool and the stroke of the spool 18 in the main control valve 17th

The proportional directional control valve 14 is a 5/4-way valve with five controlled working connections P, T, B, A and A1 as well as two controlled control connections C1 and C2 and with two further control connections X and Y for external control oil supply and discharge. Of the controlled work connections, the first work connection P is connected to a pressure source 21 , which can be a feed pump connected to a pressure oil or control oil tank, possibly combined with a pressure accumulator, the second work connection T to a pressure relief chamber, here the control oil tank 22 third working connection B with the piston chamber 12 of the working cylinder 10 , the fourth working connection A with the piston rod chamber 13 of the working cylinder 10 and the fifth working connection A1 also with the piston rod chamber 13 . The control connections C1 and C2 serve to connect a so-called pressure compensator 23 , which is formed in FIG. 1 by a controllable pressure control valve 24 . In the connecting line 25 between the fourth working connection A and the piston rod chamber 13 , a device 26 for specifying a counterpressure in the piston rod chamber 13 when the working piston 11 is displaced in FIG. 1 is arranged to the left. This device 26 is formed here by a controllable pressure relief valve 47 , the control input of which is connected to the piston chamber 12 .

The control slide 18 for controlling the individual work connections P, T, B, A and A1 and both control connections C1 and C2 is axially displaceably guided in an axial bore 27 of a valve housing 28 . The working connections and control connections are connected via branch channels to an annular channel in the valve housing 28 . The third working port B is located on a central ring channel 29 , while the two second and first working ports T and P are connected to ring channels 30 , 31 located on both sides of the central ring channel 29 . In addition to these two ring channels 30 , 31, there is a ring channel 32 and a ring channel 33 further outward. Both are dimensioned much larger in their axial width than the ring channels 29-31 . The ring channel 32 is connected to the fourth working connection A and the ring channel 33 to the fifth working connection A1. In addition to the two ring channels 32 and 33 , a narrow ring channel 34 and a narrow ring channel 35 with connections to the control connections C1 and C2 are also offset to the outside. To close and release the ring channels 29-35 , the control slide 18 carries in a known manner a plurality of control sections with control surfaces located thereon, which are delimited by control edges. When the proportional directional control valve 14 is not actuated, the control slide 18 is in its neutral center position 0 by the two centering springs 36 and 37 , in which all working connections and control connections are blocked. This position of the control slide 18 is shown in FIGS. 1 and 2. From this central position 0 , the control slide 18 can be displaced on both sides into a first and second control slide position 1 and 2 and beyond the control slide position 1 into a third control slide position 3 .

As can be seen from Fig. 1 and Fig. 2 readily in the first control slide position 1, which forwards (AV) causes the working feed the working piston 11 in Fig. 1 to the left, the first work port P to the third working port B and the second working connection T is connected to the fourth working connection A. The fifth working connection A1 and the control connection C2 are blocked. In the connection between the first working connection P and the third working connection B, a first measuring orifice 38 is switched on, the pressure difference of which lies at the control inputs of the pressure compensator 23 . For this purpose, the two control connections C1 and C2 are connected to one another and connected to the control input of the pressure control valve 24 . In addition, the annular channel 29 and an upstream of the annular channel 34 axial bore section 27 a are connected to one another via a bore 39 . The axial bore section 27 a is opened in the first control slide position 1 and connected to the ring channel 34 located at C1.

In the third control slide position 3 , which causes the rapid advance (EV) of the working piston 10 - to the left in FIG. 1 - the first and fifth working ports P and A1 are connected to one another and to the third working port B via a further measuring orifice 40 .

The further measuring orifice 40 is also realized constructively by the control edge phase 41 forming the first measuring orifice 38 on the control slide 18 ( FIG. 2). The control connection C1 is in turn connected via the bore 39 to the third working connection B located downstream of the further measuring orifice 40 . The fourth working connection A and the control connection C2 are completed.

In the second control slide position 2 , which on the one hand causes the rapid traverse backward (ER) and on the other hand the working feed backward (AR), depending on the axial displacement position of the control slide 18 , the first working connection P is connected to the fifth working connection A1, specifically via a first one Measuring aperture 42 , which is realized by the control edge chamfer 43 on the control slide 18 ( FIG. 2). In addition, the two working connections T and B are connected to one another via a throttle 44 , which is formed by the control edge phase 45 of the control slide 18 ( FIG. 2). The fourth working connection A, like the first control connection C1, is blocked. The second control connection C2 is connected to the fifth working connection A1 located downstream of the first measuring orifice 42 . This is effected by a bore 46 ( FIG. 2), which connects the ring channel 33 to an axial bore section 27 b upstream of the ring channel 35 , which is opened in the second control position 2 relative to the working connection C2. Depending on the axial displacement of the control piston 18 , the throttle cross section of the first orifice plate 42 and throttle 44 is increased or decreased, which causes the transition from ER to AR and vice versa. The throttle 44 takes over the same function of limiting the counter pressure in the piston chamber 12 during the retraction movement of the piston rod 48 as the pressure control valve 24 during the extension movement of the piston rod 48 with respect to the piston rod chamber 13 .

The operation of the device can be easily read from the circuit diagram of FIG. 1 and is therefore only briefly outlined here. In order to control the working piston 11 in FIG. 1 in EV, the proportional directional control valve 14 is controlled into its third control slide position 3 . The piston chamber 12 is pressurized by the pressure source 21 via the pressure control valve 24 . The working piston 11 runs to the left in the plunger operation, whereby the control oil in the piston rod chamber 13 is pushed out. Since the fourth working port A is blocked and the pressure relief valve 47 is closed, the control oil pushed out is fed back via the fifth working port A1 to the ring channel 31 connected to the first working port P and reaches the piston chamber 12 again via the further measuring orifice 40 and the ring channel 29 . The drop in the further orifice 40 lies on the control port C1 at the control input of the pressure control valve 24 , so that regardless of pressure fluctuations on the pressure source side or load fluctuations on the piston rod 48, a constant pressure drop across the further orifice 40 is always effective and thus a constant Volume flow for EV in the working cylinder 10 is available.

If the control slide 18 is now switched to its first slide position 1 , the first measuring orifice 38 is switched on in the connection between the first and third work connections P and B. The throttle cross section between the two working ports P and B is thus significantly reduced, so that now a small volume flow required for the AV flows to the piston chamber 12 . The pressure control valve 24 in the same way keeps the volume flow constant. Together with the pressure relief valve 47 , which is now effective as a result of the opening of the fourth working port A and the closing of the fifth working port A1, the working piston 11 runs forward at a constant feed rate, to the left in FIG. 1. The control oil pushed out flows via the pressure limiting valve 47 to the control oil tank 22 .

The AR is connected to the AV by reversing the proportional directional control valve 14 into its second control slide position 2 . Now control oil flows through the first working port P and the first orifice 42 to the fifth working port A1 and from there, bypassing the pressure relief valve 47, into the piston rod chamber 13 . The piston chamber 12 is connected to the pressure relief chamber 22 serving as a control oil tank via the third and second working connections B and T and via the throttle 44 located between them. The drop in pressure across the first orifice 42 causes the pressure control valve 24 to be adjusted accordingly, while the throttle 44 maintains a specific counterpressure in the piston chamber 12 . The working piston 11 moves to the right in FIG. 1 at a constant feed rate, the piston rod 48 being retracted. If the control spool 18 in FIG. 2 is moved a little more to the left due to stronger excitation of the proportional magnet 16 in the pilot valve 15, the throttle cross section effective between the working connections P and A1 and T and B increases. The volume flow flowing to the piston rod chamber 13 becomes significantly larger and the counterpressure in the piston chamber 12 decreases. The working piston 11 moves backwards in rapid traverse (ER) in the pulling-in direction of the piston rod 48 .

As a comparison to a known proportional directional control valve shows, as is described, for example, in DE 28 40 831 C2, the main control valve 17 according to FIG. 2 differs from the known main control valve only by slight design changes. The existing connection between the ring channels 32 and 33 in the known main control valve is removed and the ring channel 33 is connected to the fifth working connection A1 via a bore. In addition, the axial width of the ring channels 32 and 33 is slightly increased and the individual ring channels 29-33 are occupied with other work connections. With these few design changes, the known proportional directional control valve can also be used for the feed control device described.

The device for feed control of the working cylinder 10 shown in FIG. 3 largely corresponds to the device described for FIG. 1. Likewise, the proportional directional control valve 114 shown in FIG. 4 and used in the device according to FIG. 3 is identical to the proportional directional control valve 14 shown in FIG. 2, except for minor structural changes. The same components are therefore provided with the same reference numerals and only enlarged by the reference number 100 to the extent that components have been structurally changed.

In contrast to FIG. 1, in the device according to FIG. 3, the pressure compensator 23 is not connected upstream of the first working port P as a pressure reducing valve, but rather is designed as a two-way valve 50 which flows into the connecting line 49 between the third working port B and the piston chamber 12 of the working cylinder 10 is switched on. The 2-way valve 50 has a control piston 51 , which can be acted upon with control oil at the end via a first control input 52 and a second control input 53 . In addition, the control piston 51 is acted upon by a control spring 54 which acts in the same direction as a pressure applied in the first control input 52 . This is referred to as the spring preload of the first control input 52 . The control connections C1 and C2 of the proportional directional control valve 114 are in turn connected to one another and jointly connected to a working connection of a 4/2-way solenoid valve 55 . A second working connection of the valve 55 is connected to the connecting line 49 between the third working connection B of the proportional directional valve 114 and the two-way valve 50 . Of the two other working connections of the valve 55 , one is connected to the first control input 52 and the other to the second control input 53 of the 2-way valve 50 . The 4/2-way solenoid valve 55 is reversed in accordance with the actuation of the proportional directional valve 114 for the forward or backward advance of the working piston 11 , so that the pressure difference at the first or further measuring orifices 38 , 42 or 40 always falls on the 2-way valve 50 is that the smaller pressure value acts on the first control input 52 and the larger pressure value on the second control input 53 . In this case, the pressure compensator 23 formed by the 2-way valve 50 is located in the primary and inlet arrangement for AV and EV and in the secondary or outlet arrangement for AR and ER. By switching the 4/2-way solenoid valve 5 , the pressure difference is always correctly assigned to the control inputs 52 , 53 . The mode of operation of the pressure compensator 23 shown in FIG. 3 in connection with the pressure relief valve 47 is described in detail in DE 34 22 978 A1, and the advantages of such a pressure compensator 23 are also highlighted there.

The proportional directional control valve 114 is modified in comparison to the proportional directional control valve 14 in FIGS. 1 and 2 in that the connections of the control connections C1 and C2 to the work connections are modified in the control slide positions 1-3 . In the third control slide position 3 (EV), the first control connection C1 is blocked and the second control connection C2 is connected to the first control connection P located upstream of the further measuring orifice 40 . For this purpose, a bore 56 ( FIG. 4) opens on the one hand in the annular channel 31 and on the other hand in a bore section 27 c which is separated from the control slide 18 between the annular channel 33 and the annular channel 35 and which extends from the control slide 18 in the third control slide position 3 to the annular channel 35 is steered towards. In the first control slide position 1 (AV), the first control connection C1 is again blocked and the second control connection C2 is connected to the first working connection P located upstream of the first measuring orifice 38 . This also takes place via the control bore 56 . In the second control slide position 2 (ER / AR), the control connection C2 is shut off and the control connection C1 is connected to the second working connection T located downstream of the first measuring orifice 42 . For this purpose, a bore 57 is arranged in the valve housing 28 , which opens on the one hand in the annular channel 30 and on the other hand in an axial bore section 27 d lying between the two annular channels 32 and 34 , which is opened towards the annular channel 34 in the second control slide position 2 . The spatial position of the two outermost ring channels 34 , 35 in the valve housing 28 is necessarily modified compared to FIG. 2 with the same control geometry of the control slide 18 . The mode of operation of the device according to FIG. 3 with the proportional directional control valve 114 according to FIG. 4 is identical to that previously described.

The feed control device according to FIG. 5 in connection with the proportional directional control valve 214 shown in FIG. 6 is modified compared to the device in FIG. 3 in that the 4/2-way solenoid valve 55 in FIG. 3 has been omitted and that on the first or further Measuring orifices 38 , 42 and 40, the falling pressure difference is correctly assigned to the two control inputs 52 , 53 of the 2-way valve 50 by means of the control slide 218 . For this purpose, the spring-biased first control input 52 is connected to the first control connection C1 and the second control input 53 of the 2-way valve 50 is connected to the second control connection C2 of the proportional directional control valve 214 . The control geometry in the valve housing 28 is changed so that in the third spool position 3 the first control connection C1 is connected to the third working connection B located downstream of the further measuring orifice 40 and the control connection C2 is connected to the first working connection P lying upstream of the further measuring orifice 40 , while in the first control slide position 1, the first control connection C1 is connected to the third working connection B located downstream of the first measuring orifice 38 and the control connection C2 is connected to the first working connection P located upstream of the first measuring orifice 38 . In the control slide position 2 , the first control connection C1 is connected to the second working connection T located downstream of the first measuring orifice 42 and the control connection C2 is connected to the third working connection B located upstream of the first measuring orifice 42 . In addition to the bore 56 between the annular channel 31 and the axial bore section 27 c, which is also required, there is also a bore 62 between the axial bore section 27 d and the control slide valve section between the annular channel 29 and 30 in the axial bore 27 and a third bore 58 between the annular channel 29 and one provided on the annular channel 34 to the outside to adjacent axial bore portion 27 e, which is opened and closed accordingly by the control slide 218 . In addition, a further narrow annular channel 59 is arranged in the valve housing 28 , adjacent to the annular channel 34 , and is connected to the annular channel 35 via a connecting bore 60 . The control geometry of the control slide 218 is modified in the area of the ring channels 34 and 59 insofar as it carries an annular groove 61 , via which a connection from the axial bore section 27 e to the ring channel 59 or to the ring channel 34 can be established.

The operation of the control device in Fig. 5 corresponds to that in Fig. 3, the function of the 4/2-way solenoid valve 55 has been taken over by the spool geometry, so that in the different spool positions 1 , 2 and 3 at the first and Further measuring orifices 38 , 42 and 40, falling pressure difference, in correct assignment, are applied to the control inputs 52 , 53 of the 2-way valve 50 forming the pressure compensator 23 .

Another device for feed control of the working piston 11 in the working cylinder 10 is shown in FIG. 7. FIG. 8 shows the proportional directional control valve 314 , as used in the device in FIG. 7, in a partially sectioned side view. It consists, as the proportional directional control valve 14 in Fig. 1 from the actuated by a proportional magnet 16 pilot valve 15 and the hydraulically controlled by the pilot valve 15 main control valve 317th Both valves 15 , 317 are connected to one another via an intermediate plate valve 63 , which contains the 2-way valve 50 of the pressure compensator 23 . The control slide 318 of the main control valve 317 is in turn guided axially displaceably in an axial bore 17 in the valve housing 28 and is held in its neutral central position 0 via the two centering springs 36 , 37 , from where it can be deflected toward both sides. Displacement sensors 19 and 20 in turn sense the displacement of the slide connected to the proportional magnet 16 in the pilot valve 15 and the control slide 318 in the main control valve 317 .

As can be seen from the circuit diagram of the proportional directional control valve 314 in FIG. 7, the proportional directional control valve 314 is designed here as a 5/5 directional control valve, the switching positions ER and AR being assigned to two different control spool positions. Rapid reverse (ER) is assigned to a fourth spool position 4 of the spool 318 , which adjoins the second spool position 2 to the outside. The latter only causes work feed backwards (AR). The proportional directional control valve 314 is combined with the pressure compensator 23 to form a structural unit 64 , which is identified in FIG. 7 by a dash-dotted frame, while this structural unit 64 can be seen in a side view in FIG. 8. Of the five controlled work connections and the two additionally controlled control inputs of the proportional directional control valve 314 , only the first, second, third and fifth work connections P, T, B and A1 are brought out. In addition, an additional control connection Y can be provided for the external control oil drain. The first working port P is in turn connected to the pressure source 21 , the second working port T to the control oil tank 22 , the third working port B to the piston chamber 12 of the working cylinder 10 and the fifth working port A1 to the piston rod chamber 13 of the working cylinder 10 . Internally, the fourth working connection A is connected to the fifth working connection A1 via bore channels 65 and 66 in the valve housing 28 , the two bore channels 65 , 66 being connected to one another via the pressure compensator 23 , that is to say the 2-way valve 50 . The spring-biased first control input 52 of the pressure compensator 23 is connected to the control connection C1 via a bore channel 67 in the valve housing 28 and the second control input 53 is connected to the control connection C2 via a bore channel 68 in the valve housing 28 . The ring channels 29-34 are provided in the same way in the axial bore 27 of the valve housing 28 , but other working connections are assigned to them. The middle ring channel 29 is still connected to the third working connection B, while the ring channel 30 adjoining it on the left is connected to the first working connection P and the right-hand ring channel 31 is connected to the second working connection T. The ring channel 32 on the left outside has a connection to the fifth working connection A1, while the ring channel 33 on the right outside is connected to the internally connected fourth working connection A. The ring channel 34 is connected to the control connection C2 and the ring channel 35 to the control connection C1. The ring channel 30 also has a connection to a ring channel 70 , which can be opened by the control slide 318 to the ring channel 33 via a bore 69 .

As can be seen from the circuit diagram in FIG. 7, in the neutral central position 0 of the control slide 318, both the third working connection B via a throttle 71 and the fourth working connection A via a throttle 72 are connected to the second working connection T. The other work and tax connections are blocked. This relieves the piston chamber 12 and the piston rod chamber 13 of the working cylinder 10 towards the control oil tank 22 , and prevents the working piston 11 from creeping away when the proportional directional control valve 314 is not activated.

In the third spool position 3 , in which the working piston 11 is driven forward in rapid plunger circuit (EV), the first and fifth working connections P and A1 are connected to one another and connected to the third working connection B via a throttle 73 . The control connection C1 is connected to the second work connection T and the control connection C2 is connected to the fourth work connection A. In this position EV of the proportional directional control valve 314 , the first control input 52 of the pressure compensator 23 is relieved and the second control input 53 is acted upon via the fourth working connection A. The pressure compensator 23 is closed, and the control oil pushed out of the piston rod chamber 13 at EV by the working piston 11 moving to the left flows back to the inlet of the piston chamber 12 via the fifth working connection A1.

If the proportional directional control valve 314 for AV is switched to the first spool position 1 , the first and third working ports P and B are connected to each other via a throttle 74 and the fourth and second working ports A and T are connected to a first orifice 75 . The control connection C1 is connected to the second working connection T located downstream of the first measuring orifice 75 and the control connection C2 is connected to the fourth working connection A located upstream of the first measuring orifice 75 . The pressure compensator 23 acts as a secondary or discharge pressure compensator. The secondary arrangement of the pressure compensator 23 also ensures a sufficient counter-pressure in the piston rod chamber 13 .

Switches the proportional directional valve 314 to its second spool position 2 for the AR in a way, the first and fourth working ports P and A via a first orifice 76 and the third and second control terminals B and T via a throttle 77 are interconnected. The fifth work connection A1 is blocked. The control connection C1 is connected to the fourth working connection A located downstream of the first measuring orifice 76 and the control connection C2 is connected to the first working connection P located upstream of the first measuring orifice 76 . The pressure compensator 23 acts as a primary or feed pressure compensator. The counterpressure pressure in the piston chamber 12 is determined in the AR by the pressure difference dropping at the discharge throttle 77 .

For ER, the proportional directional control valve 314 is to be moved into its fourth switching position 4 . As a result, the first and fifth working connections P and A1 are connected to one another via a throttle 78 and the second and third working connections T and B via a throttle 79 . The control port C1 is connected to the fourth working port A and the control port C2 to the first working port P. Thus, the pressure compensator 23 is blocked and the pressure oil flowing into the piston rod chamber 13 via the fifth working port A1 shifts the working piston 11 to the right in rapid traverse in FIG. 7 . The counter pressure in the piston chamber 12 is determined by the voltage drop across the throttle 79 . In general, the proportional directional control valve 314 is controlled so that EV is switched on first and then switched to AV, while AR AR follows in the opposite direction, so that the proportional directional control valve 314 moves from its neutral central position 0 first to its third spool position 3 and then to the first Control spool position 1 is switched to then be reversed to the second spool position 2 and then switch to the fourth spool position 4 . Since the pressure compensator 23 is closed during the transition from EV to AV and during the transition from ER to AR, there is no start-up jump at the AV or AR start. The above-described first orifices 75 and 76 and throttles 77-79 are implemented by appropriately designing the control edges on the control slide 318 . The problems associated with the control terminals C1 and C2 annular channels 35 and 34 are connected through respective bores in the valve housing 28 with the respective ring channels, so that in the different spool positions always, the applied in the connected to the control terminal C1 annular channel 35 pressure with the smaller pressure value at the first control input 52 of the pressure compensator 23 and the pressure introduced into the ring channel 34 connected to the control connection C2 with the larger pressure value is at the second control input 53 of the pressure compensator 23 .

The invention is not restricted to the exemplary embodiments described above. In all devices, for example, a feed shift free of starting jump can be achieved if a connection is established in the neutral central position 0 of the control slide 18 or 318 between the first working connection P and the second control connection C2. In this case, the second control input 53 of the pressure compensator 23 is subjected to maximum pressure and the pressure compensator 23 closes. When changing from the central position 0 to AV or AR, the pressure compensator 23 regulates from the closed to the open state, and thus no start jump occurs.

. In the proportional directional control valves according to Fig 1-6 of the control slide 18 can, instead of the shut-off of all the working and control connections in the neutral center position 0 - as in Fig. 7 - the fourth and third working ports A and B with the second work port T connected to . Thus, the piston chamber 12 and the piston rod chamber 13 are relieved of pressure in the central position 0 of the control slide 18 , and creeping away of the working cylinder 11 when the proportional directional control valve 14 , 114 and 214 is de-energized is avoided.

Claims (24)

1. Device for feed control of a hydraulic actuator in opposite directions and different feed speeds, which has a double-acting working cylinder ( 10 ) with an axially displaceable working piston ( 11 ) therein, with a first piston surface ( 11 a) a piston chamber ( 12 ) and with a opposed smaller second piston surface (11 b) a piston rod chamber (13) limited by a pilot operated proportional directional control valve (14; 114; 214; 314) via a first working connection (P) to a pressure source (21) via a second working connection (T ) with a pressure relief chamber ( 22 ), via a third working connection (B) with the piston chamber ( 12 ) and via a fourth working connection (A) with the piston rod chamber ( 13 ) and two control connections (C1, C2) and one the valve and control connections controlling spool ( 18 ; 218 ; 318 ), which consists of a neutral The central position ( 0 ) can be axially displaced on both sides in the valve housing ( 18 ) into a first and second spool position ( 1 , 2 ), in which the working piston ( 11 ) is acted on in opposite displacement directions, with one together with one by the spool ( 18 ; 218 ; 318 ) in the control oil flow switchable first orifice plate ( 38 , 42 ; 75 , 76 ) a pressure regulator ( 23 ) forming a current regulator, which is connected to the control connections (C1, C2) of the proportional directional control valve ( 14 ; 114 ; 214 ; 314; ) and two Has control inputs ( 52 , 53 ) at which the pressure difference which arises at the first measuring orifice ( 38 , 42 ; 75 ; 76 ), the control input ( 52 ), which is always occupied with the lower pressure value, being spring-loaded in the opening direction of the pressure compensator ( 23 ) is biased, and with a device ( 26 ) for specifying a counterpressure in the piston rod chamber ( 13 ) which is effective when the working piston ( 11 ) is displaced, characterized in that the proportional directional control valve ( 14 ; 114 ; 214 ; 314 ) has a fifth one, controlled by the control slide ( 18 ; 218 ; 318 ) controlled work connection (A1), which is connected to the piston rod chamber ( 13 ) bypassing the counter pressure device ( 26 ), and that the control circuit boar ( 18 ; 218 ; 318 ) can be moved beyond the first control slide position ( 1 ) into a third control slide position ( 3 ), in which the first and fifth working ports (P, A1) and both via a further orifice plate ( 40 ) or throttle ( 73 ) with the third Valve connection (B) are connected and the fourth working connection (A) is shut off. 2. Apparatus according to claim 1, characterized in that the pressure compensator ( 23 ) is designed as a controllable pressure control valve ( 24 ) which is arranged between the first working port (P) of the proportional directional control valve ( 14 ) and the pressure source ( 21 ) that both control ports (C1, C2) of the proportional directional control valve ( 14 ) are connected to the control input of the pressure control valve ( 24 ) and that in the third spool position ( 3 ) one control connection (C2) is shut off and the other control connection (C1) is connected to the downstream of the further measuring orifice ( 40 ) lying third working connection (B) is connected ( Fig. 1 and 2). 3. Apparatus according to claim 2, characterized in that in the first control slide position ( 1 ), the first measuring aperture ( 38 ) in the connection between the first and the third working connection (P, B) that the one control connection (C2) is shut off and the other control connection (C1) is connected to the third work connection (B) located downstream of the first measuring orifice ( 38 ) and that the fourth work connection (A) is connected to the second work connection (T) and the fifth work connection (A1) is shut off ( Fig . 1 and 2). 4. Apparatus according to claim 2 or 3, characterized in that in the second control slide position ( 2 ), the first measuring aperture ( 42 ) in the connection between the first working connection (P) and the fifth working connection (A1) is that the one control connection ( C1) is blocked and the other control connection (C2) is connected to the fifth working connection (A1) located downstream of the first measuring orifice ( 42 ) and that the third working connection (B) is connected to the second working connection (T) via a throttle ( 44 ) and the fourth working connection (A) is blocked ( Fig. 1 and 2). 5. The device according to claim 1, characterized in that the pressure compensator ( 23 ) is designed as a separate from the directional control 2-way valve ( 50 ) between the third working port (B) of the proportional directional control valve ( 114 ) and the piston chamber ( 12 ) of the working cylinder ( 10 ) that the two control connections (C1, C2) are connected to one another and a 4/2-way solenoid valve ( 55 ) which alternately controls the control connections (C1, C2) and the third working connection (B) of the proportional directional control valve ( 114 ) to the two control inputs ( 52 , 53 ) of the 2-way valve ( 50 ) that the 4/2-way valve ( 55 ), depending on the spool positions, assumes such a switching position that the 2-way valve ( 50 ) in the first and third spool position ( 1 , 3 ) acts as a primary or inlet pressure compensator and in the second spool position ( 2 ) acts as a secondary or outlet pressure compensator and that in the third spool position on ( 3 ) one control connection (C1) is blocked and the other control connection (C2) is connected to the first working connection (P) located upstream of the further measuring orifice ( 40 ) (FIGS . 3 and 4). 6. The device according to claim 5, characterized in that in the first spool position ( 1 ), the first orifice ( 38 ) in the connection between the first and third work port (P, B) and the one control port (C1) shut off and the other Control connection (C2) is connected to the first working connection (P) located upstream of the measuring orifice ( 38 ) and that the second and fourth working connection (T, A) are connected to one another and the fifth working connection (A1) is shut off ( Fig. 3 and 4). 7. The device according to claim 5 or 6, characterized in that in the second spool position ( 2 ), the first measuring aperture ( 42 ) in the connection between the second and the third working connection (T, B), which shuts off a control connection (C2) and the other control connection (C1) is connected to the second work connection (T) located downstream of the first measuring orifice ( 42 ) and that the first work connection (P) is connected to the fifth work connection (A1) via a throttle ( 44 ) and the fourth work connection (A) is blocked ( Fig. 3 and 4). 8. The device according to claim 1, characterized in that the pressure compensator ( 23 ) is designed as a separate from the directional control 2-way valve ( 50 ) between the third working port (B) of the proportional directional control valve ( 214 ) and the piston chamber ( 12 ) of the working cylinder ( 10 ) that the first (C1) of the two control connections (C1, C2) with the spring-biased control input ( 52 ) and the second control connection (C2) with the other control input ( 53 ) of the 2-way valve ( 50 ) is connected and that the control spool ( 218 ) controls the control connections (C1, C2) such that the 2-way valve ( 50 ) in the first and third spool positions ( 1 , 3 ) as a primary or inlet pressure compensator and in the second spool position ( 2 ) acts as a secondary or discharge pressure compensator ( Fig. 5 and 6). 9. The device according to claim 8, characterized in that in the third spool position ( 3 ), the first control connection (C1) with the downstream of the further measuring orifice ( 40 ) lying third working connection (B) and the second control connection (C2) with the upstream of the another measuring orifice ( 40 ) lying first working connection (P) is connected ( Fig. 5 and 6). 10. The device according to claim 8 or 9, characterized in that in the first control slide position ( 1 ), the first measuring aperture ( 38 ) in the connection between the first and third working connection (P, B), that the first control connection (C1) with the third working connection (B) located downstream of the first measuring orifice ( 38 ) and the second control connection (C2) are connected to the first working connection (P) lying upstream of the first measuring orifice ( 38 ) and that the fifth working connection (A1) is shut off ( Fig . 5 and 6). 11. The device according to claim 9 or 10, characterized in that in the second spool position ( 2 ), the first orifice ( 42 ) in the connection between the second and third work port (T, B), the first control port (C1) with the the second working connection (T) located downstream of the first measuring orifice ( 42 ) and the second control connection (C2) are connected to the third working connection (B) located upstream of the first measuring orifice ( 42 ) and that the first working connection (P) is connected via a throttle ( 44 ) is connected to the fifth working connection (A1) and the fourth working connection (A) is blocked ( FIGS. 5 and 6). 12. Device according to one of claims 1 to 11, characterized in that the device ( 26 ) for specifying a counter pressure in the piston rod chamber ( 13 ) of the working cylinder ( 10 ) is formed by a controllable pressure relief valve ( 47 ) which is between the fourth working connection (A) of the proportional directional control valve ( 14 ; 114 ; 214 ) and the piston rod chamber ( 13 ) of the working cylinder ( 10 ) and the control input of which is connected to the piston chamber ( 12 ). 13. The apparatus according to claim 1, characterized in that the control spool ( 318 ) of the proportional directional control valve ( 314 ) over the second spool position ( 2 ) in a fourth spool position ( 4 ) is displaceable, in which on the one hand the first and fifth working connection (P, A1) and on the other hand the second and third working connection (T, B) are connected to each other via a throttle ( 78 , 79 ) such that the pressure compensator ( 23 ) between the fourth working connection (A) and the piston rod chamber ( 13 ) of the working cylinder ( 10 ) arranged and with its two control inputs ( 52 , 53 ) each with a control connection (C1, C2) of the proportional directional control valve ( 314 ), the spring-biased control input ( 52 ) of the pressure compensator ( 23 ) always being connected to the first control connection (C1) that the control slide ( 318 ) controls the control connections (C1, C2) such that the pressure compensator ( 23 ) in the first control slide position ( 1 ) as a secondary r or discharge pressure compensator acts and at the same time forms the device for specifying the counter pressure in the piston rod chamber ( 13 ) of the working cylinder ( 10 ) and acts as a primary or inlet pressure compensator in the second spool position ( 2 ) and in the third and fourth spool position ( 3 , 4 ) is closed ( Fig. 7 and 8). 14. The apparatus according to claim 13, characterized in that in the third spool position ( 3 ) the first control connection (C1) with the second working connection (T) and the second control connection (C2) with the fourth working connection (A) is connected ( Fig. 7 and 8). 15. The apparatus according to claim 13 or 14, characterized in that in the fourth spool position ( 4 ) the first control connection (C1) with the fourth working connection (A) and the second control connection (C2) is connected to the first control connection (P) ( FIGS. 7 and 8). 16. The device according to one of claims 13 to 15, characterized in that in the first control slide position ( 1 ), the first measuring aperture ( 75 ) lies in the connection between the second and fourth working connection (T, A) and the first control connection (C1) is connected to the second working connection (T) located downstream of the first measuring orifice ( 75 ) and the second control connection (C2) is connected to the fourth working connection (A) lying upstream of the first measuring orifice ( 75 ) and that the fifth working connection (A1) is shut off and in the connection between the first and third working connection (P, B) a throttle ( 74 ) is switched on. ( Figs. 7 and 8). 17. The device according to one of claims 13 to 16, characterized in that in the second control slide position ( 2 ), the first measuring aperture ( 76 ) lies in the connection between the first and fourth working connection (P, A) and the first control connection (C1) is connected to the fourth working connection (A) located downstream of the first measuring orifice ( 76 ) and the second control connection (C2) is connected to the first working connection (P) located upstream of the first measuring orifice ( 76 ) and that in the connection between the second and third working connection (T, B) a throttle ( 77 ) is turned on ( Fig. 7 and 8). 18. Device according to one of claims 5 to 17, characterized in that in the central position ( 0 ) of the control slide, the first working connection (P) is connected to that control connection (C2) which is connected to the non-spring-biased control input ( 53 ) of the pressure compensator ( 23 ) is connected, and that all other work and control connections (T, B, A, A1, C1) are blocked. 19. Device according to one of claims 1 to 18, characterized in that in the central position ( 0 ) of the control slide ( 318 ), the second, third and fourth work connection (T, B, A) are connected to one another and all other work and control connections (P, A1, C1, C2) are blocked. 20. Device according to one of claims 1 to 17, characterized in that in the central position ( 0 ) of the control slide ( 18 ; 218 ) all work and control connections (P, T, B, A, A1, C1, C2) are blocked . 21. Device according to one of claims 13 to 20, characterized in that the proportional directional valve ( 314 ) consists of a main control valve ( 317 ) and a pilot valve ( 15 ) and the pressure compensator ( 23 ) as an intermediate plate valve ( 63 ) between the housing of the main and pilot valve ( 317 , 15 ) is arranged. 22. The apparatus according to claim 21, characterized in that from the structural unit ( 64 ) of pilot, main control and intermediate plate valve ( 15 , 317 , 63 ) only the first, second, third and fifth working connection (P, T, B, A1 ) are brought out. 23. Device according to one of claims 1 to 22, characterized in that the working and control connections (P, T, B, A, A1, C1, C2) open in the axial sliding direction of the control slide arranged side by side ring channels ( 29-35 ) which can be opened or closed by control surfaces arranged on cylinder sections of the control slide ( 18 ; 218 ; 318 ) via the control surfaces bordering the control surfaces. 24. The device according to claim 23, characterized in that the throttles and metering orifices ( 38 , 40 , 42 , 44 ) are formed by chamfering on the control edges of the control surfaces, which for adjusting different throttle cross sections in the axial direction of the control slide ( 18 ; 218 ) steadily - or lose weight.