DE3813020A1 - Arrangement for the feed control of a hydraulic actuator - Google Patents

Abstract

An arrangement for the feed control of a double-acting hydraulic cylinder (10) with regard to direction and speed has a pilot-controlled proportional directional valve (14) for the alternative activation of the pressure chambers (12, 13) of the working cylinder (10) and a pressure balance (23) which together with a device (26) for predetermining a counterholding pressure in the one pressure chamber provides for a feed rate independent of pressure and load fluctuations. To reduce the requisite components in the arrangement, the proportional directional valve (14) known per se is provided with a fifth working connection (A1) and a third control spool position (3), and the fifth working connection (A1), while bypassing the counterholding-pressure device (26), is connected to the same pressure chamber (13) of the working cylinder (10) as the counterholding-pressure device (26). The third control spool position (3) brings about the rapid forward motion (EV), whereas in the first control spool position (1) only the forward working feed (AV) is triggered. The rapid return motion (ER) and the return working feed (AR), depending on the axial displacement of the control piston (18), are still triggered in the second control spool position (2) lying on the other side of the spring-centred centre position (0) of the control spool (18) (Fig. 1). <IMAGE>

Description

State of the art

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 operated 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 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 backwards (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 on the printed side, e.g. the pressure source is fed.

Advantages of the invention

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 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 with a work connection stands, locked and a hole to the other ring channel is led, which is the additional fifth work connection forms. The latter ring channel is additionally in its axial width increases and the Pressure tapping 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 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 Pressure oil flowing back to the working cylinder immediately Piston chamber fed. With a variety of Feed units e.g. in transfer streets, that of oil flow to be supplied to the hydraulic pump considerably be made smaller. In the known known at the beginning The device, on the other hand, flows in the EV through the usual Setting 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 a reduction in the electrical drive power to be installed, the pump delivery flow or the storage size and the cooling power. This means - especially in the case of a larger number of feed drives in one machine, for example a transfer line - a smaller electric motor for driving the feed pump, a smaller feed pump and / or a smaller accumulator and a smaller oil cooler or the same is eliminated.

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, namely the piloted Proportional directional control 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, 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 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. 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, which means that 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, i.e. 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. This 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, however, is designed there as a 4/3-way valve, 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 A 1 as well as two controlled control connections C 1 and C 2 and with two further control connections X and Y for the external control oil supply and discharge. Of the controlled work connections, the 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 work connection T to a relief chamber, here the control oil tank 22 , the work connection B with the piston chamber 12 of the working cylinder 10 , the working connection A with the piston rod chamber 13 of the working cylinder 10 and the fifth working connection A 1 also with the piston rod chamber 13 . The control connections C 1 and C 2 serve to connect a so-called pressure compensator 23 , which in FIG. 1 is formed by a controllable pressure control valve 24 . In the connecting line 25 between the working port 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 pushed to the left in FIG. 1 is arranged. 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 A 1 and both control connections C 1 and C 2 is axially displaceably guided in an axial bore 27 of a valve housing 28 . The work connections and control connections are connected via branch channels to an annular channel in the valve housing 28 . The working connection B is located on a central ring channel 29 , while the two working connections 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 communicates with the working connection A and the ring channel 33 with the working connection A 1 . 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 C 1 and C 2 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 working port P to the work port B and the working connection T connected to the working port A. The working connection A 1 and the control connection C 2 are blocked. In the connection between the working connection P and the working connection B , a 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 C 1 and C 2 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 C 2 .

In the third spool position 3 , which causes the rapid advance (EV) of the working piston 10 - to the left in FIG. 1 - the working connections P and A 1 are connected to one another and to the working connection B via a measuring orifice 40 .

The measuring orifice 40 is also structurally realized by the control edge phase 41 forming the measuring orifice 38 on the control slide 18 ( FIG. 2). The control connection C 1 is in turn connected via the bore 39 to the working connection B located downstream of the throttle 40 . The working connection A and the control connection C 2 are completed.

In the second spool 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 spool 18 , the working port P is connected to the fifth working port A 1 , via a measuring orifice 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 working connection A is blocked off just like the first control connection C 1 . The second control connection C 2 is connected to the working connection A 1 located downstream of the measuring orifice 42 . This is brought about by a bore 46 ( FIG. 2), which connects the annular channel 33 to an axial bore section 27 b upstream of the annular channel 35 , which is opened in the second control position 2 relative to the working connection C 2 . Depending on the axial displacement of the control piston 18 , the throttle cross section of the 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 regulating 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 working port A is blocked and the pressure relief valve 47 is closed, the control oil pushed out is fed via the fifth working port A 1 back to the ring channel 31 connected to the first working port P and reaches the piston chamber 12 again via the measuring orifice 40 and the ring channel 29 . The pressure drop at the orifice 40 lies via the control connection C 1 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 orifice 40 is always effective and thus a constant volume flow is available for EV in the cylinder 10 .

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

The AR is connected to the AV by reversing the proportional directional control valve 14 into its second control slide position 2 . Control oil now flows via the control connection P and the orifice plate 42 to the working connection A 1 and from there passes the pressure limiting valve 47 into the piston rod chamber 13 . The piston chamber 12 is connected to the control oil tank 22 via the working connections B and T and via the throttle 44 located between them. The drop in pressure across the orifice 42 causes the pressure control valve 24 to be adjusted accordingly, while the throttle 44 maintains a certain 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 somewhat 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 A 1 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 via a bore to the fifth working connection A 1 . 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, the pressure compensator 23 in the device according to FIG. 3 is not connected upstream of the working port P as a pressure reducing valve, but rather is designed as a two-way valve 50 which is switched on in the connecting line 49 between the working port B and the piston chamber 12 of the working cylinder 10 is. The 2-way valve 50 has a control piston 51 , which can be acted upon with control oil at the front 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 C 1 and C 2 of the proportional directional control valve 114 are in turn connected to one another and connected together 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 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 according to the control of the proportional directional control valve 114 for forward or backward feed of the working piston 11 , so that the pressure difference dropping at the orifice plates 38 , 40 , 42 is always on the 2-way valve 50 such that the smaller one Pressure value acts on the first control input 52 and the larger pressure value on the second control input 53 . The pressure compensator 23 formed by the 2-way valve 50 is located in AV and EV in the primary or inlet arrangement and in AR and ER in the secondary or outlet arrangement. By switching the 4/2-way solenoid valve 55 , 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 relation to the proportional directional control valve 14 in FIGS. 1 and 2 in that the connections of the control connections C 1 and C 2 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 C 1 is shut off and the second control connection C 2 is connected to the first control connection P located upstream of the orifice plate 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 C 1 is again blocked and the second control connection C 2 is connected to the working connection P located upstream of the measuring orifice 38 . This also takes place via the control bore 56 . In the second control slide position 2 (ER / AR), the control connection C 2 is shut off and the control connection C 1 is connected to the working connection T located downstream of the 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 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 has been omitted in FIG. 3 and that on the measuring orifices 38 , 40 , 42 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 18 . For this purpose, the spring-biased first control input 52 is connected to the first control connection C 1 and the second control input 53 of the 2-way valve 50 is connected to the second control connection C 2 of the proportional directional control valve 214 . The control geometry in the valve housing 28 is changed such that in the third control slide position 3 the first control connection C 1 is connected to the working connection B located downstream of the measuring orifice 40 and the control connection C 2 is connected to the working connection P lying upstream of the measuring orifice 40 , while in the first Control spool position 1, the first control connection C 1 is connected to the working connection B located downstream of the measuring orifice 38 and the control connection C 2 is connected to the working connection P lying upstream of the measuring orifice 38 . In the control slide position 2 , the first working connection C 1 is connected to the working connection T lying downstream of the measuring orifice 42 and the control connection C 2 is connected to the working connection B lying upstream of the measuring orifice 42 . In addition to the likewise required bore 56 between the annular channel 31 and the axial bore section 27 c, there is also a bore 62 between the axial bore section 27 d and the axial bore section 27 e lying between the annular channel 29 and 30 , and a third bore 58 between the annular channel 29 and one on the annular channel 34 to the outside to the adjacent axial bore section 27 e is provided, which is opened and closed accordingly by the control slide 218 . In addition, a further narrow ring channel 59 is arranged in the valve housing 28 , adjacent to the ring channel 34 , and is connected to the ring 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 in that 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 mode of operation of the control device in FIG. 5 corresponds to that in FIG. 3, the function of the 4/2-way solenoid valve 55 having been taken over by the control slide geometry, so that that in the different control slide positions 1 , 2 and 3 on the measuring orifices 38 , 40 , 42 falling pressure difference in correct assignment is 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 315 , as used in the device in Fig. 8, 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 to 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 now 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 working connections and the two additionally controlled control inputs of the proportional directional control valve 314 , only the working connections P , T , B and A 1 are brought out. In addition, an additional control connection Y can be provided for the external control oil drain. The working connection B is in turn connected to the pressure source 21 , the working connection T with the control oil tank 22 , the working connection B with the piston chamber 12 of the working cylinder 10 and the working connection A 1 with the piston rod chamber 13 of the working cylinder 10 . Internally, the working connection A is connected to the working connection A 1 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 C 1 via a bore channel 67 in the valve housing 28 and the second control input 53 is connected to the control connection C 2 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 working connection B , while the ring channel 30 adjoining it on the left is connected to the working connection P and the ring channel 31 on the right is connected to the working connection T. The ring channel 32 on the left outside has a connection to the working connection A 1 , while the ring channel 33 on the right outside is connected to the internally connected working connection A. The ring channel 34 has a connection to the control connection C 2 and the ring channel 35 to the control connection C 1 . The ring channel 30 also has a connection to a ring channel 70 via a bore 69 , which can be opened by the control slide 318 to the ring channel 33 .

As can be seen from the circuit diagram in FIG. 7, in the neutral central position 0 of the control slide 318, both the working connection B via a throttle 71 and the working connection A via a throttle 72 are connected to the 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 working connections P and A 1 are connected to one another and connected to the working connection H via a throttle 73 . The control connection C 1 is connected to the working connection T and the control connection C 2 is connected to the working 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 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 working connection A 1 .

If the proportional directional control valve 314 for AV is switched to the first spool position 1 , the working connections P and H are connected to each other via a throttle 74 and the working connections A and T via a measuring orifice 75 . The control connection C 1 is connected to the working connection T located downstream of the measuring orifice 75 and the control connection C 2 is connected to the working connection A located upstream of the 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 working ports P and A via a metering orifice 76 and the control terminals B and T via a throttle 77 are interconnected. The work connection A 1 is blocked. The control connection C 1 is connected to the working connection A located downstream of the measuring orifice 76 and the control connection C 2 is connected to the control connection P lying upstream of the measuring orifice 76 . The pressure compensator 23 acts as a primary or feed pressure compensator. The counter pressure in the piston chamber 12 in the AR is determined 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 working connections P and A 1 are connected to one another via a throttle 78 and the working connections T and B via a throttle 79 . The control connection C 1 is connected to the working connection A and the control connection C 2 is connected to the working connection P. The pressure compensator 23 is thus blocked and the pressure oil flowing into the piston rod chamber 13 via the working connection A 1 shifts the working piston 11 in rapid traverse in FIG. 7 to the right. The counterpressure 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 control 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 measuring orifices 75 and 76 and throttles 77-79 described above are implemented by appropriately designing the control edges on the control slide 318 . The ring channels 35 and 34 connected to the control connections C 1 and C 2 are connected to the corresponding ring channels via corresponding bores in the valve housing 28 , so that in the different control slide positions the pressure introduced into the ring channel 35 connected to the control connection C 1 is always associated 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 C 2 with the larger pressure value 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 made in the neutral central position 0 of the control slide 18 or 318 between the first working port P and the second control port C 2 . 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 there is no start jump.

. In the proportional directional control valves according to Fig 1-6 18 may instead of the shut-off of all the working and control connections in the neutral center position 0 of the valve spool - also be connected to the working ports A and B with the work port T - as well as in Fig. 7. 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 with the de-energized proportional directional control valve 14 , 114 and 214 is avoided.

Claims (24)

1. Device for feed control of a hydraulic actuating device 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 ( C 1 , C 2 ) and one Has valve and control connections controlling spool ( 18 ; 218 ; 318 ), which consists of a neutral The central position ( 0 ) can be moved axially on both sides in the valve housing ( 28 ) into a first and second control position ( 1 , 2 ), in which the working piston ( 11 ) is acted on in opposite directions of displacement, with one together with one by the control slide ( 18 ; 218 ; 318 ) in the control oil flow switchable orifice ( 38 , 40 , 42 ; 75 , 76 ) a pressure regulator ( 23 ) forming a flow controller, which is connected to the control connections ( C 1 , C 2 ) of the proportional directional control valve ( 14 ; 114 ; 214 ; 314 ) and has two control inputs ( 52 , 53 ) at which the pressure difference which arises at the measuring orifice ( 38 , 40 , 42 ; 75 , 76 ) is located, the control input ( 52 ) always occupied with the lower pressure value in the opening direction of the pressure compensator ( 23 ) is biased by spring force, 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, has the working connection ( A 1 ) controlled by the control slide ( 18 ; 218 ; 318 ), which is connected to the piston rod chamber ( 13 ) bypassing the counter-pressure device ( 26 ), and that the control slide ( 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 , A 1 ) and both via a measuring orifice ( 40 ) or throttle ( 73 ) with the third Valve connection ( B ) are connected and the fourth working connection ( A ) is shut off. 2. Device according to claim 1, characterized in that the pressure compensator ( 23 ) is designed as a controllable pressure control valve ( 24 ) which is connected between the first working port ( P ) of the proportional directional control valve ( 14 ) and the pressure source ( 21 ) that both control ports ( C 1 , C 2 ) of the proportional directional control valve ( 14 ) are connected to the control input of the pressure regulating valve ( 24 ) and that in the third spool position ( 3 ) one control port ( C 2 ) is shut off and the other control port ( C 1 ) is connected to the downstream one the measuring orifice ( 40 ) is connected to the working connection ( B ) ( FIGS. 1 and 2). 3. Apparatus according to claim 2, characterized in that in the first control slide position ( 1 ), the measuring orifice ( 38 ) in the connection between the first and the third working connection ( P , B ) is that the one control connection ( C 2 ) completed and the other control connection ( C 1 ) is connected to the third work connection ( B ) located downstream of the measuring orifice ( 38 ) and that the fourth work connection ( A ) is connected to the second work connection ( T ) and the fifth work connection ( A 1 ) is shut off ( Fig. 1 and 2). 4. Apparatus according to claim 2 or 3, characterized in that in the second spool position ( 2 ), the orifice ( 42 ) in the connection between the first working connection ( P ) and the fifth working connection ( A 1 ) is that the one control connection ( C 1 ) is blocked and the other control connection ( C 2 ) is connected to the fifth working connection ( A 1 ) located downstream of the measuring orifice ( 42 ) and that the third working connection is connected to the working connection ( T ) via a throttle ( 44 ) and the fourth Work port ( 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 ) the working cylinder ( 10 ) is arranged so that the two control connections ( C 1 , C 2 ) are connected to each other and a 4/2-way solenoid valve ( 55 ), which alternately the control connections ( C 1 , C 2 ) and the third working connection ( B ) of the proportional directional control valve ( 114 ) to the two control inputs ( C 1 , C 2 ) of the 2-way valve ( 50 ) that the 4/2-way solenoid valve ( 55 ) takes on such a switching position depending on the spool positions that the 2-way valve ( 50 ) acts in the first and third spool positions ( 1 , 3 ) as a primary or inlet pressure compensator and in the second spool position ( 2 ) as a secondary or outlet pressure compensator and in the third control spool Erposition ( 3 ) the one control port ( C 1 ) is shut off and the other control port ( C 2 ) is connected to the first working port ( P ) located upstream of the measuring orifice ( 40 ) (FIGS . 3 and 4). 6. The device according to claim 5, characterized in that in the first spool position ( 1 ), the orifice ( 38 ) in the connection between the first and third work port ( P , B ) and one control port ( C 1 ) shut off and the other Control port ( C 2 ) is connected to the first working port ( P ) located upstream of the measuring orifice ( 38 ) and that the second and fourth working ports ( T , A ) are connected to one another and the fifth working port (A 1 ) is shut off ( Fig. 3 and 4). 7. Apparatus according to claim 5 or 6, characterized in that in the second spool position ( 2 ), the metering orifice ( 42 ) in the connection between the second and the third working connection ( T , B ), which shuts off a control connection ( C 2 ) and the other control connection (C 1 ) is connected to the downstream second work connection ( T ) and that the first work connection ( P ) is connected to the fifth work connection ( A 1 ) via a throttle ( 44 ) and the fourth work connection ( A ) is shut off is ( Figs. 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 ) the working cylinder ( 10 ) is arranged so that the first of the two control connections ( C 1 ) with the spring-biased control input ( 52 ) and the second control connection ( 2 ) with the other control input ( 53 ) of the 2-way valve ( 50 ) and that the control spool ( 218 ) controls the control connections ( C 1 , C 2 ) 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 ) as Secondary or discharge pressure compensator acts ( Fig. 5 and 6). 9. The device according to claim 8, characterized in that in the third spool position ( 3 ), the first control connection ( C 1 ) with the downstream of the orifice ( 40 ) lying third working connection ( B ) and the second control connection ( C 2 ) with the upstream the measuring orifice ( 40 ) is connected to the first working connection ( P ) ( FIGS. 5 and 6). 10. The device according to claim 8 or 9, characterized in that in the first control slide position ( 1 ), the metering orifice ( 38 ) in the connection between the first and third work connection ( P , B ), that the first control connection ( C 1 ) with the third working connection ( B ) located downstream of the measuring orifice ( 38 ) and the second control connection ( C 2 ) is connected to the first working connection ( P ) lying upstream of the measuring orifice ( 38 ) and that the fifth working connection ( A 1 ) is shut off ( Fig . 5 and 6). 11. The device according to one of claims 9-11, characterized in that in the second control slide position ( 2 ), the measuring orifice ( 42 ) in the connection between the second and third working connection ( T , B ), the first control connection ( C 1 ) is connected to the second working connection ( T ) located downstream of the measuring orifice ( 42 ) and the second control connection ( C 2 ) is connected to the third working connection ( B ) located upstream of the measuring orifice ( 42 ) and that the first working connection ( P ) is connected via a throttle ( 44 ) is connected to the fifth working connection (A 1 ) and the fourth working connection ( A ) is blocked ( FIGS. 5 and 6). 12. Device according to one of claims 1-11, characterized in that the device ( 26 ) for specifying a counterpressure 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 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 ) on 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 , A 1 ) and on the other the second and third working connection ( T , B ) are connected to each other via a throttle ( 78 , 79 ) so that the pressure compensator ( 23 ) is arranged between the fourth working connection ( A ) and the piston rod chamber ( 13 ) of the working cylinder ( 10 ) and with its two control inputs ( 52 , 53 ) are each connected to a control connection ( C 1 , C 2 ) of the proportional directional control valve ( 314 ), the spring-loaded control input ( 52 ) of the pressure compensator ( 23 ) always being connected to the first control connection ( C 1 ), that the control slide ( 318 ) controls the control connections ( C 1 , C 2 ) such that the pressure compensator ( 23 ) in the first control slide position ( 1 ) as a secondary or discharge pressure compensator we kt 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 is closed in the third and fourth spool positions ( 3 , 4 ) ( Figs. 7 and 8). 14. The apparatus according to claim 13, characterized in that in the third spool position ( 3 ) the first control connection ( C 1 ) with the second working connection ( T ) and the second control connection ( C 2 ) with the fourth working connection ( A ) is connected ( FIGS. 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 (C 1 ) with the fourth working connection ( A ) and the second control connection ( C 2 ) connected to the first control connection ( P ) is ( Figs. 7 and 8). 16. Device according to one of claims 13-15, characterized in that in the first control slide position ( 1 ), the measuring orifice ( 75 ) is in the connection between the second and fourth working connection ( T , A ) and the first control connection ( C 1 ) is connected to the second working connection ( T ) located downstream of the measuring orifice ( 75 ) and the second control connection ( C 2 ) is connected to the fourth working connection ( A ) lying upstream of the measuring orifice ( 75 ) and that the fifth working connection ( A 1 ) is shut off and in the connection between the first and third working connection ( P , B ) a throttle ( 74 ) is switched on ( Fig. 7 and 8). 17. Device according to one of claims 13-16, characterized in that in the second control slide position ( 2 ), the measuring orifice ( 76 ) lies in the connection between the first and fourth working connection ( P , A ) and the first control connection ( C 1 ) is connected to the fourth working connection ( A ) located downstream of the measuring orifice ( 76 ) and the second control connection ( C 2 ) is connected to the first valve connection ( P ) located upstream of the measuring orifice ( 76 ) and that the connection between the second and third valve connection ( T , B ) a throttle ( 77 ) is turned on ( Fig. 7 and 8). 18. Device according to one of claims 5-17, characterized in that in the central position ( 0 ) of the control slide, the first working connection ( P ) is connected to that control connection ( C 2 ) 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 , A 1 , C 1 ) are blocked. 19. Device according to one of claims 1-18, 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 , A 1 , C 1 , C 2 ) are blocked. 20. Device according to one of claims 1-17, characterized in that in the central position ( 0 ) of the control slide ( 18 ; 218 ) all working and control connections ( P , T , B , A , A 1 , C 1 , C 2 ) are cordoned off. 21. Device according to one of claims 13-20, characterized in that the proportional directional valve ( 314 ) consists of a main control valve ( 317 ) and a pilot valve ( 315 ) 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 , A 1 ) are brought out. 23. Device according to one of claims 1-22, characterized in that the working and control connections ( P , T , B , A , A 1 , C 1 , C 2 ) in the axial sliding direction of the control slide arranged side by side ring channels ( 29- 35 ) open, which can be opened or closed by control surfaces arranged on cylinder sections of the control slide ( 18 ; 218 ; 318 ) via the control surfaces delimiting control edges. 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.