WO2017081202A1

WO2017081202A1 - Electro-hydraulic drive unit

Info

Publication number: WO2017081202A1
Application number: PCT/EP2016/077348
Authority: WO
Inventors: Josef RITZL; Stefan GUTH; Roland Thurner; Ilker ÖZCANOGLU
Original assignee: Hoerbiger Automatisierungstechnik Holding Gmbh
Priority date: 2015-11-13
Filing date: 2016-11-10
Publication date: 2017-05-18
Also published as: EP3317088B1; DE102016119823A1; DE202015106161U1; CN108136707B; CN108136707A; ES2755813T3; EP3317088A1

Abstract

An electro-hydraulic drive unit comprises: - a cylinder-piston assembly (1) that includes a first hydraulic working chamber (10) associated with a first moving direction (Y1) of the piston (9) as well as a second hydraulic working chamber (11) associated with an opposite second moving direction (Y2) of the piston (9); - a tank (2) storing a hydraulic fluid; - a two-quadrant hydraulic pump (5) which, in the pumping mode, is driven by an electric motor (4) at variable speeds in exactly one predefined rotational direction and which has a tank connection leading directly into the tank (2) as well as a pressure connection (29); - and a valve assembly which is mounted between the pressure connection (29) of the hydraulic pump (5) and the cylinder-piston assembly (1) and which includes a plurality of electrically controllable switching valves (S1-S6).

Description

Electrohydraulic drive unit

The present invention relates to a

electro-hydraulic drive unit, in particular for use on a machine press.

Electrohydraulic drive units, like them

in particular for use on machine presses

(in particular for moving up and down the relevant

Tool) are suitable and intended are in

various designs and designs known.

Typically, the respective drive units are designed so that the piston (at least in one of the two directions of movement) with

Different speeds can be moved, namely on the one hand with a rapid traverse (with comparatively low achievable pressing force) and on the other hand with a power gear (with comparatively high achievable pressing force). Two fundamentally different concepts of the electro-hydraulic drive machine presses differ in that for the rapid down movement of the tool carrier / tool unit either an active admission of the sink working space of the cylinder-piston unit (s) of the

(respective) hydraulic unit is required,

Namely, because the permanently acting restoring force of a spring device is overcome, or the tool carrier / tool unit due to their

Dead weight until the contact of the tool with the

Workpiece (braked) sinks and alone for the

subsequent power passage of the sink working space of Cylinder-piston unit (s) from the (respective)

Hydraulic unit is acted upon. To the extent

Relevant prior art include, for example, WO 2011/003506 AI, US 2010/0212521 AI, AT 8633 Ul, DE 102012013098 AI, WO 2011/021986 AI, EP 103727 AI and DE 102013000725 AI.

The present invention is concerned with

Electro-hydraulic drive units, as used for machine presses according to the second of the above-mentioned concepts (rapid downwards movement of the tool carrier / tool unit as a result of

Own weight) are suitable. Typical such

Electro-hydraulic drive units include a

Cylinder-piston arrangement with one of a first

Direction of movement of the piston associated first

hydraulic workspace and one of a kind

opposite second movement direction of the piston associated second hydraulic working space, a hydraulic fluid-storing tank, a driven by an electric motor hydraulic pump, a switched between the hydraulic pump and the cylinder-piston arrangement, electrically controllable

Switch valves comprehensive valve assembly and acting on the switching valves and the electric motor

Machine control, by means of which the switching valves between a loading of the first hydraulic working space and the second hydraulic working space of the cylinder-piston assembly in the pumping operation of

Hydraulic pump from the pressure port are reversible.

Electro-hydraulic drive devices of the type in question here must in practice a number of Meet requirements that are partly in conflict with each other. Be required, depending on the

individual installation situation more or less

particularly high performance, compact dimensions, ease of maintenance, durability,

Reliability, low production costs, high

Energy efficiency, operational safety, high dynamics, stable operating behavior even under strongly changing conditions and low noise emission.

The present invention has set itself the task of providing an electro-hydraulic drive unit, which with regard to typical requirements, as in particular in applications of presses

a balanced, particularly practicable compromise.

This object is achieved according to the present invention by, as indicated in claim 1, in one of the features set forth above

electrohydraulic drive unit, the hydraulic pump is designed as a 2-quadrant hydraulic pump, which by means of a (in particular designed as a servo motor) electric motor in the pumping operation (for an active movement of the piston in both directions of movement, ie downwards for pressing in power and up to lift the tool carrier / tool Unit) in exactly one

predetermined direction of rotation is driven variable speed and a directly (ie., Typically, without further controls) opening in the tank

Tank connection and a pressure connection, wherein the hydraulic pump continues to use the

Machine control in a braking operation with the Pump operation reverse rotational and flow direction is reversible. This way can be with you

comparatively low expenditure on equipment

powerful, reliable and reliable

provide electro-hydraulic drive unit, which also meets the other requirements set out above to a high degree.

Particularly preferred is in the inventive

electro-hydraulic drive unit, the cylinder-piston assembly with at least substantially vertical

Movement axis oriented, with the first

Moving direction of a downward movement and the second direction of movement corresponds to an upward movement of the piston. And the hydraulic pump is both in a first movement phase (rapid-down), while (via the valve assembly) is a flow connection of the second hydraulic working space of the cylinder-piston assembly with the pressure port of the hydraulic pump, as well as in a second movement phase (decompression-up ), in which there is a flow connection of the first hydraulic working space of the cylinder-piston arrangement with the pressure connection of the hydraulic pump, in the braking operation uncontrollable.

Particularly preferred is a throttle

(For example, in the form of a nozzle) is provided, which is connected in braking mode in the second movement phase in series with the hydraulic pump. This relieves the hydraulic pump and limits its stress in the

Braking operation during the second movement phase, so that possibly the process safety affecting operating conditions (overspeeding) are avoided. In alternative training without such

Throttle gets done in the decompression phase, d. H. in the second movement phase during the

Brake operation, a pressure-dependent control of the speed of the hydraulic pump driving - or in this mode of operation - braking electric motor. In that regard, a pressure sensor is provided in this case, which detects the pressure prevailing in the first hydraulic working space pressure and the signal is switched to the machine control.

According to another preferred embodiment of

Invention, the hydraulic pump is disposed inside lying in the tank. This allows a laid inside the tank flow to the pressure outlet of the

Hydraulic pump subsequent pressure line, which represents a significant advantage from the standpoint of reliability and continues to be favorable to

Minimizing the risk of external leakage. In addition, this is under aspects of low noise emission and a constant cooling of the hydraulic pump advantage.

Yet another preferred embodiment of

inventive electro-hydraulic drive unit is characterized in that a flange and

Terminal block is provided with a first

Flange surface for connection to a valve block housing the switching valves and a second

Flange surface for connection to the cylinder

Cylinder-piston assembly. The flange and

Terminal block can in particular to a

most of its volume can be arranged in the tank and only adjacent to the two flange surfaces Edge areas more or less far from this

protrude. According to an alternative preferred

Continuing education is the flange and connection block

meanwhile, arranged outside the tank, and that

more preferably below its bottom. In the sense of the above statements, the hydraulic pump can thereby

in particular be connected via a pressure line extending within the tank with a pressure connection provided on the flange and connection block, which in turn communicates via a channel with a pressure connection provided on the first flange surface; and at the first as well as the second

Flange surface can each have a hydraulic

Provided interface, which two with the two working spaces of the cylinder-piston assembly

communicating work connections.

According to yet another preferred embodiment of the invention, the valve block is housed in a lateral recess of the tank. In particular, such, the valve block receiving recess may be arranged in one of the corner regions of the tank.

Yet another preferred embodiment of

The invention is characterized in that a hydraulically releasable suction valve is arranged in the tank. Particularly advantageous is the arrangement of the

Nachsaugventils in a breakthrough of the above described, to a large part of his

Volume arranged in the tank flange and

Terminal block; the suction valve can do this

in turn, a connecting flange for direct connection with the cylinder of the cylinder-piston assembly exhibit. In a preferred alternative development, the suction valve is completely in the - arranged outside the tank - flange and

Integrated connection block; only the latter is connected via its second flange directly with the cylinder of the cylinder-piston assembly. And the

Suction valve can be provided via a control line with one on the flange and connection block

Control output be connected. The control output of

Flange and connection block stands on a channel with a control fluid interface on the first

Flange surface in connection.

From the above explanations it can be seen that in application of the present invention a

Electro-hydraulic drive unit with distinct advantages (especially in the case of use as

Drive a machine press) can provide.

These include in particular: By factory

Pre-assembled and tested units, which are equipped with a mechanical interface to the respective cylinder-piston arrangement and thus easy to connect to the latter, resulting in minimal

Assembly and commissioning times on the machine. The piping-reduced design and the consistent avoidance of external piping result

maximum reliability and reduced risk of external leakage. The drive unit uses a small amount of hydraulic fluid. It has a low temperature dependence on a very high energy efficiency, so that usually neither a designated oil cooling time is provided, nor an oil cooler is needed. So can the drive unit have particularly small dimensions. The

Noise is minimal. By means of

Valve control is a return stroke of the tool in

Working speed possible. This results in particularly short cycle times and a correspondingly high cycle time

Productivity possible. Additional functions like

Tool clamping and crowning can be done without

Integrate additional effort in the drive unit or connect to this. The drive unit comes without

Accumulator and without proportional directional valves off. Nor does it necessarily require any

Pressure sensors, although such may certainly be provided with advantage in certain embodiments of the drive unit according to the invention (see above). A variable displacement pump is not required. Highly dynamic machine presses (eg press brakes) can be realized with a rapid traverse speed of

for example 200-230mm / sec.

In the following, the present invention will be more apparent from the two illustrated in the drawings

Embodiments explained in more detail. It shows

Fig. 1 in perspective view a

Electro-hydraulic drive unit according to a first embodiment of the invention without the associated machine control,

Fig. 2, the electro-hydraulic drive unit according to

1 with partially cut side walls of the tank to illustrate its internals, but without the cylinder-piston unit, the hydraulic circuit diagram to the

electrohydraulic drive unit according to FIGS. 1 and 2,

in the form of a diagram, the control of the switching valves and the electric motor of the

electro-hydraulic drive unit according to Figures 1 to 3 and the resulting movement of the piston,

in perspective view one

Electro-hydraulic drive unit according to a second embodiment of the invention without the associated machine control,

the hydraulic circuit diagram to the

electrohydraulic drive unit according to Fig. 5 (without the associated machine control) and a control of the switching valves and the electric motor of the electro-hydraulic drive unit according to Figures 5 and 6 and the resulting movement of the piston

illustrative function diagram.

The electro-hydraulic drive unit according to a first exemplary embodiment of the invention shown in FIGS. 1 and 2 comprises as main components a cylinder-piston arrangement 1 with a vertical movement axis Y, a tank 2 storing a hydraulic fluid

Hydraulic unit 3 with an electric motor 4 and a driven by this hydraulic pump 5 and a valve block 6 with a plurality of disposed thereon or housed therein hydraulically active elements

(In particular valves) and a change-oil filter 20. The cylinder-piston assembly 1 includes in a manner known per se linear in a cylinder 7 displaceable, connected to a piston rod 8 piston 9, through which the interior of the cylinder 7 is divided into two working spaces, namely a first hydraulic working space 10, which is so associated with a first direction of movement Yl of the piston, that during this increases its volume, and a second hydraulic working space 11 which is associated with a second movement direction Y2 of the piston, which is opposite to the first movement direction Y1, during which it increases its volume. In the existing installation position corresponds to the first

Movement direction Yl of the downward movement of piston 9 and piston rod 8 and the second direction of movement Y2 their upward movement.

The tank 2, which is ventilated via a ventilation filter 12, so that in it ambient pressure prevails (so-called.

"open system") has an L-shape. He thus has a lateral recess 13 in which the valve block 6 is housed. On one of the side walls of the tank 2, a level sensor 34 is arranged.

The hydraulic pump 5 is disposed inside the tank 2 ("under oil"). However, the drive 4 serving electric motor 4 is located outside of the tank 2, flanged to the bottom 14. Also in the tank 2 are a suction valve 15 and (with a major part of its volume) a flange and terminal block 16. However, the latter protrudes through corresponding openings in the side wall 17 and the bottom 14 of the tank 2 out of this. At the protruding through the side wall 17 of the tank portion 18 of the flange and

Terminal block 16 is a first flange 19 for Connection provided with the valve block 6; and on the protruding through the bottom 14 of the tank 2 portion of the flange and terminal block 16 is a second flange 21 for connection to the cylinder 7 of the cylinder-piston assembly 1. At the first and the second flange 19, 21 is respectively a

provided hydraulic interface, which comprises two communicating with the two working spaces 10, 11 of the cylinder-piston assembly 1 working ports A, B.

The flange and connection block 16 has an opening 22, in which the Nachsaugventil 15 is inserted. This in turn has a connection flange for direct connection to the cylinder 7 of the

Cylinder-piston arrangement 1. The Nachsaugventil 15 is hydraulically unlocked, what it over a - within the tank 2 routed - control line 23 with a provided on the flange and terminal block 16

Control terminal is connected, which in turn via a - the flange and terminal block 16 passing through

- Channel and one on the first flange 19th

provided control fluid interface with a

Control output of the valve block 6 communicates.

At the tank side of the hydraulic pump 5, which forms the suction side in their pumping operation, a near-ground opening intake 24 is provided. The pressure side of the hydraulic pump 5, at the pumping in which the

delivered hydraulic fluid escapes is

in contrast, via a - laid inside the tank 2

- Pressure hose 25 with a on the flange and

Terminal block 16 provided pressure connection connected Which in turn has a flange and

Terminal block 16 passing through channel and provided on the first flange 19 Druckfluid- interface with a pressure fluid port of the

Valve block 6 communicates.

The arrangement and connection of the switching valves and other components (suction valve, throttle,

Pressure relief valves, filters, etc.) of

Hydraulic circuit is illustrated in Fig. 3. (To avoid misunderstanding, it should be noted that in Fig. 3 the line symbolizing the valve block 6 comprises the physical valve block 6 of Figures 1 and 2 together with the bodily flange and terminal block 16, these two components structurally separate according to Figures 1 and 2 could well be grouped into a single component)

Of particular importance for the control of the movements of the drive unit, d. H. the downward and upward movement of piston 9 and piston rod 8 are the total of six controlled by the machine control 26 switching valves Sl to S6 and also controlled by the machine control 26, as

Servomotor 27 running electric motor 4 of the

Hydraulic unit 3. The control of the switching valves Sl to S6 and the servomotor 27 in the individual

Subsections and phases of a complete cycle 'is illustrated in the diagram of FIG. 4.

Namely, during the holding of the piston at the top dead center (phase I), the servomotor 27 is at a standstill

(Operating state "0"); and none of the six switching valves Sl to S6 is activated, so that all switching valves the in Fig. 3 shown position (switching position "0")

taking. In this switching state, the piston 9 is held redundantly by the group of closed switching valve S2 and closed pressure limiting valve 30 as well as the likewise closed switching valve S3 in the sense that the weight of the connected to the piston rod 8 components (eg tool carrier and

Tool) of the respective machine by the clamped in the second hydraulic working space 11

Hydraulic fluid are kept. (The safety valve 28, which is set to the maximum permissible system pressure plus an additional charge, is always closed in normal operation anyway.)

For movement Eil-down of piston 9 and piston rod 8 (phase II) are with the exception of the switching valve S4

all switching valves, d. H. the switching valves Sl, S2, S3, S5 and S6 activated (switch position "I"). The second working space 11 (lifting-working space) of the cylinder-piston unit 7 is connected to the pressure port 29 of the hydraulic pump 5 via the (opened) switching valves S2 and S3 and the switching valve S5 opened according to bP. The servomotor 27 rotates in reverse (operating state L *), d. H. in its braking operation, by the weight of the driven by the drive unit, with the

Piston rod 8 connected driven

Machine component (tool carrier plus tool) induced downward movement of the piston 9 controlled to brake. By Nachsaugventil 15 is the first

Working space 10 of the cylinder-piston assembly 7 filled directly from the tank 2. This Phase II extends to a - stored in the machine control - switching point, the freely programmable and is suitably chosen near the touchdown of the tool on the workpiece.

In the load change phase III, the servomotor 27 is at a standstill. The switching valves S2, S4 and S5 are reversed, ie the switching valves S2 and S5 are deactivated (switching position "0") _/ and the switching valve S4 is activated (switching position "I"). In this way, the first working chamber 10 of the cylinder-piston assembly 7 via the switching valve S4 with the pressure side 29 of

Hydraulic pump 5 brought into fluid communication. The second working chamber 11 of the cylinder-piston assembly 7 is in contrast via the pressure relief valve 30, the switching valve S3, the flow path BT of the switching valve S5 and the oil filter 20 with the tank side in

Brought flow connection.

For power pressing (phase IV), the servomotor 27 with its pumping operation of the hydraulic pump. 5

corresponding direction of rotation (clockwise according to

Operating status R *). This

Operating state of the switching valves Sl to S6 and the

Servomotor 27 is also on the subsequent

Hold phase (phase V) maintained.

For decompressing the hydraulic fluid in the first working chamber 10 (phase VI), the servomotor 27 is reversed. He now turns in reverse, d. H. in its braking operation L *, so that

Hydraulic fluid controlled from the first working space 10 via the switching valve S4 and the (as a nozzle

executed) throttle 31 is conveyed into the tank 2. At the end of the decompression phase, the switching valves S4, S5 and S6 are reversed, ie the switching valves S4 and S6 are deactivated (switching state "0") and the

Switching valve S5 is activated (switching state "I"). As a result of its application of control pressure via the switching valve S6 (path Pb), the suction valve 15 is opened (unlocked). And the second working space 11 of the cylinder-piston arrangement 7 is connected to the pressure side 29 of the hydraulic pump 5 via the admission pressure valve 32 and the two switching valves S3 and S2 (in each case through the path protected by the check valve). By reversing the servomotor 27 in clockwise, d. H. Operation with his pumping the hydraulic pump

corresponding direction of rotation (operating state R *), the piston 9 is raised in the rapid-stroke (Phase VII). If necessary, the lifting of the piston 9 in two phases

be subdivided by the express lifting is first preceded by a slow lifting. During this first partial phase can, with not yet unlocked suction valve 15, which displaced from the first working space 10

Hydraulic fluid via the switching valve S4 (path aT) and the oil filter 20 into the tank 2 drain.

Upon reaching the top dead center (TDC) goes the

Servomotor 27 in standstill via; and the switching valves Sl and S5 are reversed, so now again

all switching valves are deactivated (holding phase VIII, analogous to the holding phase I at the beginning of the cycle, see above).

In the holding phase I, VIII, the hydraulic pump 5 can, if necessary, be put into operation to

Hydraulic fluid via the (opened) switching valve Sl through the oil filter 20 to promote. Optionally, an oil cooler 33 can be connected to the oil filter 20, connected in series therewith.

For the sake of completeness, in the context of the present invention, various variations, modifications and variations are possible for the control illustrated in FIGS. 3 and 4, without departing from the invention as defined by the claims. Such a modification exists

for example, in the replacement of normally-open (NO) valves by normally-closed (NG) valves and / or vice versa.

In Fig. 3 it is illustrated that the switching valves Sl, S2, S3, S4 and S6 are equipped with a switch position monitoring 34. This can - in the case of lesser

Safety requirements - possibly omitted, in which case the switching valve S3 can be omitted.

If, as mentioned above and illustrated in FIG. 3, an optional oil cooler 33 is provided, then this is

preferably arranged directly outside on one of the side walls of the tank 2. The oil supply to the oil cooler 33 takes place via a - inside the tank 2 laid pipe, which is connected to a provided on the flange and terminal block 16 cooling power connection, which in turn via a - the flange and terminal block 16 passing through - channel and at the first

Flange surface 19 provided cooling flow interface with a cooling flow connection of the valve block. 6

communicates. The documented by the figures 5 to 7 second preferred embodiment of the invention is explained - due to the existing parallels or

Matches - to a considerable extent by the above explanations to the first embodiment concerned by the figures 1 to 4. To avoid repetition, reference is made to the latter. However, special attention should be drawn to the relevant deviations discussed below as follows:

The flange and port block 16 'is not located in the tank, but rather (completely) outside the tank 2'. He is namely below the tank 2 ', d. H. Unlike the first embodiment, in which a self-functional suction valve in a recess or an opening of the flange and terminal block

is used, in the second embodiment of Figures 5-7, the Nachsaugventil 15 'in the sense in the flange and terminal block 16' integrated, as the latter itself forms the functionally necessary valve housing. This allows a particularly compact design. Further eliminates the required according to the first embodiment double flange connection (on the one hand of the flange and terminal block 16 and on the other hand of the Nachsaugventils 15) of components to the cylinder-piston assembly.

Furthermore, it can be seen in FIG. 6 that the throttle which is operative in the decompression phase in the first exemplary embodiment and is connected in series with the hydraulic pump in series is omitted. Herewith in

Connection is the (in the second embodiment provided) pressure-dependent control of the decompression by appropriate control of the hydraulic pump 5 in braking operation by the controller, for which purpose the signal of a hydraulic pressure in the first hydraulic working chamber detecting pressure sensor 34 is connected to the controller.

In the second embodiment, the filtering of the hydraulic fluid is designed differently. Here, a filter unit 35 is provided such that in the pumping operation of the hydraulic pump 5, the entire of

the latter pumped hydraulic fluid through the

Filter 20 'is cleaned. Only with constipation of the

Filter 20 'flows from the hydraulic pump 5'

conveyed hydraulic fluid through the "small" bypass 36, in which the check valve 37 as a

Pressure relief valve acts and loaded or

clogged filter 20 'opens to prevent filter breakage. During braking operation of the hydraulic pump 5 ', the hydraulic fluid flows past the filter unit 35 via the "large" bypass 38.

As a result of the above-described embodiment of

Filtration of the hydraulic fluid is still

partly the function of the first

Embodiment provided switching valve Sl omitted; because there is the second

Embodiment no pure circulation filter operation more. Thus, the second embodiment could make do with a switching valve less than the first

Embodiment. However, as shown in FIG. 6, for safety reasons, a shut-off valve S7

added. This locks in his non-energized Position the hydraulic pump 5 from the other valve assembly and prevents in this way unintentional pressure build-up in the system.

Attention should finally be drawn to the omission of a separate oil cooler; because such is not required in the illustrated second embodiment.

Claims

claims

1. Electrohydraulic drive unit, in particular for use on a machine press, comprising

- A cylinder-piston assembly (1) with a

a first direction of movement (Yl) of the piston

(9) associated first hydraulic working space

(10) and one of an opposite second direction of movement (Y2) of the piston (9)

associated second hydraulic working space

(11),

- A hydraulic fluid-storing tank (2;

2 '),

- one by means of an electric motor (4) in

Pumping operation in exactly one predetermined

Direction of rotation variable speed driven 2-quadrant hydraulic pump (5) with a

immediately opening in the tank (2; 2 ')

Tank connection and a pressure connection (29),

- one between the pressure port (29) of

Hydraulic pump (5) and the cylinder-piston assembly (1) connected, a plurality of electrically controllable switching valves (S1-S6; S2'-S6 ', S7) comprising valve assembly,

- And on the switching valves (S1-S6; S2'-S6 ', S7) and the electric motor (4) acting machine control (26), by means of which the switching valves (S1-S6; S2'-S6', S7) between a Loading the first hydraulic

Working space (10) and the second hydraulic working space (11) of the cylinder-piston assembly (1) in the pumping operation of the hydraulic pump (5) from the pressure port (29) are reversible, wherein the hydraulic pump (5) by means of

Machine control (26) in a braking operation with reverse pumping operation for rotary and

Flow direction is reversible.

Electro-hydraulic drive unit according to claim 1, characterized in that the cylinder-piston arrangement (1) with at least substantially

vertical movement axis (Y) is oriented, wherein the first direction of movement (Yl) a

Downward movement and the second direction of movement (Y2) of an upward movement of the piston (9)

corresponds.

Electrohydraulic drive unit according to claim 1 or claim 2, characterized in that the hydraulic pump (5) both in a first

Movement phase, while a flow connection of the second hydraulic working space (11) of the

Cylinder-piston assembly (1) with the pressure port (29) of the hydraulic pump (5) consists, as well as in a second phase of movement, in the one

Flow connection of the first hydraulic

Working space (10) of the cylinder-piston assembly (1) with the pressure port (29) of the hydraulic pump (5), in the braking operation is reversible.

4. Electrohydraulic drive unit according to claim 3, characterized in that a throttle (31) is provided, which in the braking operation in the second movement phase in series with the hydraulic pump (5) is connected.

5. Electrohydraulic drive unit according to one of claims 1 to 4, characterized in that the hydraulic pump (5) is disposed inside lying in the tank (2, 2 ').

6. Electrohydraulic drive unit according to one of claims 1 to 5, characterized in that a flange and connection block (16) is provided with a first flange (19) for connection to a switching valves (S1-S6; S2'-S6 ', S7)

accommodating valve block (6) and a second flange surface (21) for connection to the cylinder (7) of the cylinder-piston assembly (1).

7. Electro-hydraulic drive unit according to claim 6, characterized in that the flange and

Terminal block (16) to a majority of its volume in the tank (2) is arranged.

8. Electrohydraulic drive unit according to claim 6 or claim 7, characterized in that the valve block (6) in a lateral recess (13) of the tank (2, 2 ') is housed.

9. Electro-hydraulic drive unit according to one of claims 6 to 8, characterized in that on the second flange (21) a hydraulic interface is provided which two with the two working spaces (10, 11) of the cylinder-piston Arrangement (1) communicating working connections (A, B).

10. Electrohydraulic drive unit according to one of claims 6 to 9, characterized in that the hydraulic pump (5) via a within the tank (2) extending pressure line (25) with the flange and connection block (16) is connected.

11. Electrohydraulic drive unit according to one of claims 1 to 10, characterized in that in the tank (2) a Nachsaugventil (15) with a hydraulically releasable check valve

is arranged.

12. Electrohydraulic drive unit according to claim 11, characterized in that the Nachsaugventil (15) has a connection flange for immediate

Connection with the cylinder (7) of the cylinder-piston assembly (1).

13. Electro-hydraulic drive unit according to claim 11 or claim 12, characterized in that the Nachsaugventil (15) via a control line (23) is connected to a on the flange and terminal block (16) provided for control output.

14. Electro-hydraulic drive unit according to claim 6, characterized in that the flange and

Terminal block (16 ') below the tank (2') is arranged.

15. Electrohydraulic drive unit according to claim 14, characterized in that in the flange and connection block (16 ') a Nachsaugventil (15') is arranged with a hydraulically releasable check valve.

16. Electrohydraulic drive unit according to one of claims 1 to 15, characterized in that it comprises a filter unit (35) with a pumping operation of the hydraulic pump (5) of the entire of the

Hydraulic pump (5) funded hydraulic fluid flowed through filter (20 ') comprises.