DE19816069A1 - Compressed oil supply system for vehicle automated gear shift - Google Patents

Abstract

The compressed oil supply system for a vehicle, such as in an automated gear shift, has a valve fitted with a pressure connection (P), a tank connection (T) and a working connection (KA), with a piston (35) which can close their control cross-sections. The piston has a security setting where the working connection is separated from the tank connection. The piston shrouds the tank connection with a cover (Ue2). A further working connection (PG) is separated from the pressure connection by the piston, in the security setting. The piston setting is adjusted by a magnet against a spring force.

Description

The invention relates to a pressure oil supply unit for the power vehicle sector, preferably for automated manual transmissions of motor vehicles, according to the preamble of claim 1.

Automated manual transmissions are hydraulically operated Actuators are provided with which to select the alley of a transmission and a gear shaft rotated about its axis for engaging gear how to move axially. Another hydraulically operated one Actuating actuator opens and closes the clutch. The public NEN takes place against the force of the clutch spring by pressure oil striking. Closing takes place with the force of the clutch spring through pressure oil relief. The pressure oil loading and relief takes place via a position control loop with a hydraulic 3/2-way Proportional valve. The valve piston is when the solenoid is not energized Ver under the force of the valve return spring in the starting position pushed. In this position the working connection is from the pressure finally separated and relieved to the tank. The clutch is through her Return spring closed with full force. With fully energized Ma The valve piston is in the position under the force of the magnet for maximum clutch opening speed ben. In this position the working connection with the pressure is on finally connected and the connection of the work connection to Tank closed. The clutch is opened so that the  Do not touch the clutch discs anymore and therefore not a moment is transmitted. This position must be during gear changes will hold. The valve is activated by appropriate partial energization piston into the "center position" under the force of the return spring pushed back and adjusted by the position control loop so that the actuator holds this open clutch position as long as the Gear change takes place. There is a balance of power between the hydraulically generated actuator force and the force of the clutch closing spring required. After the gear change, the part current is further reduced and thereby the valve pistons under the Force the return spring to a position corresponding to that current driving condition required closing speed of the Clutch shifted. In this position the work connection is from Pressure oil connection separated and ver to the tank in a throttle position bound, which determines the required closing speed. If the magnet fails in this position, the valve piston becomes un ter the force of the valve return spring at maximum speed moved to the starting position. This results in an excessive Closing speed of the clutch, which is caused by occurring Mo tips can damage components.

The invention has for its object the generic Form the pressure oil supply unit so that in the event of a malfunction The clutch does not close abruptly.

This task is in the generic pressure oil supply unit according to the invention with the characterizing features of Claim 1 solved.

The piston of the clutch valve of the pressure oil according to the invention supply unit is in the safety position in which the magnet is de-energized, in a stroke position in which it connects the work from Disconnects the tank connection. This allows the clutch of the motor vehicle  in the event of a malfunction, for example if the magnet fails, do not close suddenly. There is therefore no danger that the full torque is transmitted unexpectedly. Is the Piston at the time of the malfunction in a deflected stroke position, then it becomes abrupt due to the force of the return spring pushed back into the safety position and thereby a quick Displacing the hydraulic medium from the clutch cylinder in reliably prevented the tank.

Further features of the invention result from the other An sayings, the description and the drawings.

The invention is illustrated by some in the drawings Exemplary embodiments explained in more detail. Show it

Fig. 1 is a circuit diagram of a generating unit Druckölversor according to the invention,

Fig. 2 in axial section a Druckölversor supply unit according to the invention, prior to docking of the connector and the plug-in part

Fig. 3 is a view of a terminal plate of the inventive SEN pressure oil supply unit of Fig. 2,

FIGS. 4 and Fig. 5 in views corresponding to FIGS. 2 and 3, the dung OF INVENTION proper pressure oil supply unit in the docked state,

6 shows in axial section a ken. OF INVENTION A second embodiment to the invention pressure oil supply unit prior to Andoc,

Fig. 7 is a view of a terminal plate of the inventive SEN pressure oil supply unit shown in FIG. 6,

Fig. 8 and Fig. 9 in representations corresponding to Figs. 6 and 7, the dung OF INVENTION proper pressure oil supply unit in the docked state,

Fig. 10 to Fig. 15 different shift positions of a valve of the pressure oil supply to the invention OF INVENTION unit,

Fig. 16 is a comparison of a known valves, and the pressure oil supply unit according to the invention.

The pressure oil supply unit is seen for the motor vehicle sector and is used in particular for use in automated manual transmissions in motor vehicles. Fig. 1 shows a clutch 1 of such a vehicle in the closed state. It has a clutch cylinder 2 which is connected to a valve 3 . The different positions of this valve 3 will be explained in detail with reference to FIGS . 10 to 15. The valve 3 has the connections P, K _A , T and P _G. The valve 3 has a triple function depending on the stroke position of the piston in a manner yet to be described. Regarding the connections P, K _A and T, the valve 3 is a three-way proportional valve with which a position control loop of the coupling 1 is built up. The second function of the valve 3 is that it separates the leakage-prone valves of a gear actuator 4 , which are connected to the connection P _G , from the storage-loaded line P. The third function of the valve 3 is a safety function.

The gear actuator 4 has two switching valves 5 and 6 for the shift movement and two proportional pressure reducing valves 7 and 8 for the ge movement. The valves 5 , 6 are assigned to a shift actuator 9 , with which a (not shown) shift shaft of the transmission of the motor vehicle is rotated around its axis or shifted ver depending on the design of the transmission. The shift actuator 9 has a piston 10 which can be acted upon on both sides and which separates two pressure spaces 11 and 12 from one another. The two pressure chambers 11 , 12 are connected to the connection A of the respective switching valve 5 , 6 . By appropriate pressurization of the Kol ben 10 is moved in the desired direction.

Two pressure chambers 13 , 14 of a gear actuator 15 are connected to the connections A of the valves 7 , 8 . Appropriate pressure is applied to one of the pressure chambers 13 , 14 separating piston 16 in the desired direction and with the necessary pressure. With the actuators 9 , 15 , the shift shaft of the motor vehicle transmission is shifted in a known manner or rotated about its axis for selecting the alley and for engaging the gear.

The valve 3 is connected via the tank connection T to a tank 17 or oil reservoir. The tank 17 is arranged in the installed position in the area above the connections T, P _G and K _{A of} the valve 3 . This has the advantage that the suction side of a pump 18 , with which the hydraulic oil is conveyed in the system, is constantly filled with the hydraulic oil by the action of gravity, so that the pump 18 cannot run empty and suck in air.

A memory 19 is secured to the pump 18 via a check valve 20 . This ensures that the memory 19 is not emptied via the pump to the tank 17 when a motor 21 of the pump 18 is at a standstill. A pressure sensor 22 measures the pressure in the accumulator 19 and ensures that if the pressure drops below a predetermined value, the motor 21 is switched on and the pump 18 fills the accumulator 19 again via the check valve 20 . If an upper pressure level is reached, the motor 21 is switched off via the pressure sensor 22 .

The tank 17 is preceded by a safety valve 23 , which ensures that too high a pressure does not occur in the hydraulic system if, for example, an electronics connected upstream of the pressure sensor 22 or the pressure sensor 22 itself fails. The safety valve 23 is set so that its opening pressure is slightly higher than the upper switching point of the pressure sensor 22nd

If, for example, repair measures are to be carried out on parts of the pressure oil supply unit, a drain cock 24 can be opened so that the hydraulic oil in the reservoir 19 can flow back into the tank 17 .

The pump 18 is preceded by a filter 25 with which contamination in the hydraulic oil can be retained.

The clutch cylinder 2 is associated with a measuring system 26, with which the path of a piston of the clutch cylinder 2 is detected 27th The actuators 9 , 15 are also each assigned a displacement measuring system 28 , 29 with which the path of the piston 10 , 16 of the actuators 9 , 15 can be detected.

The piston 27 of the clutch cylinder 2 engages via a tappet 30 on a one-armed clutch lever 31 which can be pivoted about the axis 32 . A pivot bearing 33 of the clutch is displaced by pivoting the clutch lever 31 . A Belleville spring 34 is supported on it under spring force. The clutch is opened or closed depending on the pivoting direction of the clutch lever 31 . The clutch 1 itself can of course have any other suitable ge design training.

Fig. 16 shows in the upper half of a known valve 3 speaking valve accordingly. If a magnet 36 is not energized, a piston 35 of this valve is maximally displaced against the magnet 36 under the force of a return spring 37 . In this position of the piston 35 , the connection from the pump P and the accumulator to the coupling connection K _{A is} blocked, while the connection from the coupling connection K _A to the tank connection T is completely open. The clutch is closed in this valve position. Is the vehicle with the engine running and the start gear engaged, for example, at a traffic light, then the clutch 1 is closed so far that the two clutch disks are in contact with one another so that a slight forward force acts on the vehicle, as is the case with automatic transmissions with an engaged gear is known. This slight forward drive is intercepted by the driver by operating the brake. Should in this situation the Ma gnet 36 fail, break the corresponding electrical cable or another malfunction occur that causes the piston 35 to be displaced under the force of the return spring 37 at an increased speed against the magnet 36 , then the clutch closes accordingly quickly . This is due to the fact that the coupling connection K _{A is} connected to the tank connection T and in this way the hydraulic oil is displaced from the coupling cylinder into the tank within a very short time. This hydraulic medium is displaced from the clutch cylinder by the restoring force of the clutch spring. In this way, the clutch is quickly closed and the full torque is transmitted. Since, as mentioned, the driver has applied the brake and the engine is idling, in this situation there will be no damage to the components, but the engine will come to a standstill by "stalling".

In this position of the piston 35 , which is shown in Fig. 16 at the top Darge and is referred to as the control position, a web 38 of the piston 35 in relation to the coupling connection K _{A takes} such a position that the two control edges 39 , 40 this known Valve are symmetrical to the edges 41 , 42 of the connection K _A. If the piston 35 is pushed from this control position to the front or back, the connection K _{A is} opened immediately and thus relieved to the tank T. In the control position of the piston 35 , the clutch is positioned in the desired stroke position. If the clutch is to be opened or closed, the flow cross-sections for the hydraulic medium in this known valve must be opened correspondingly wide, taking into account the desired lifting speed. The web 38 of the piston 35 is moved in the desired direction. In the normal case, the piston 35 is shifted ben from the re regulating position symmetrically in the plus or minus direction. If the clutch is fully closed, then the piston 35 is under the force of the return spring 37 in its maximum stroke position against the magnet 36 , which in this case is de-energized. On the other hand, if the clutch is open, the magnet 36 is energized so that the piston 35 is displaced against the force of the return spring 37 . The web 38 closes the connection between the connections K _A and T in this case. The hydraulic medium can be pumped from the accumulator 19 via the opened connection K _A to the coupling by means of the pump.

In the valve 3 of the pressure oil supply unit, the stroke of the piston 35 is divided up in a different way when using the same surface magnet 36 than in the previously described piston of the known valve.

A part of the total stroke of the piston 35 of the valve 3 is used for a securing position or securing function, in order to avoid the problem previously described with the aid of the known valve. The working stroke of the valve 3 is thus smaller than the total stroke and, based on the total stroke of the piston of the known valve, is also smaller than the total stroke. For this reason, an asymmetrical stroke distribution of the piston 35 of the valve 3 takes place , as will be described in detail below.

In the switching position 0 in FIG. 10, the safety position, the piston 35 is maximum 37 Retired advanced under the force of the return spring. The magnet 36 is without current. The piston 35 has three spaced webs 43 , 38 , 44 , which have different widths. The widest web 43 has the control edge 45 , the somewhat narrower web 38 has the two control edges 39 , 40 and the narrowest web 44 has the control edge 46 . These piston-side control edges are assigned on the socket side the control edges 47 of the tank connection T, the control edges 41 , 42 of the coupling connection K _A and the control edge 48 of the pressure connection P.

In the switching position 0, the web 44 closes the connection from the pressure connection P to the connection P _G , to which the leakage-oiled valves 5 to 8 of the gear actuator 4 are connected. The middle web 38 separates-in the switching position 0, the pressure port P from the work port K _A. The web 43 finally separates the connection from the working connection K _A to the tank connection T. This position of the piston 35 results when the magnet 36 is damaged, for example, the connecting cable is defective or, for example, the plug connection from the cable to the magnet 36 is released. Even if a fault occurs in the electronics or if the vehicle is parked and the ignition is switched off, the piston 35 assumes the switch position 0 according to FIG. 10. The web 44 closes with an overlap Ü ₁ and the web 43 with an overlap Ü ₂ .

Clutch 1 must be open to start the vehicle. If the vehicle was parked with a gear engaged, it can only be started when the clutch is disengaged or clutch 1 is open. If the ignition key of the vehicle is turned, the measuring system 26 reports to the clutch cylinder 2 that the clutch 1 is closed. A corresponding signal is then generated, which opens clutch 1 and then actuates the starter.

To open the clutch 1 , the piston 35 is moved by energizing the magnet 36 against the force of the return spring 37 in the switching position 4 ( Fig. 14). Starting from the switching position 0, the piston 35 first reaches the switching position 4 according to FIG. 14, in which the web 44 opens the connection between the Druckan circuit P and the connection P _G. The piston 35 is in the control position.

If the magnet 36 is fully energized ( FIG. 15), it is displaced further by the impacts 49 of the magnet 36 against the force of the return spring 37 . The web 38 is now displaced so far that there is a connection between the pressure port P and the port K _A , so that the hydraulic medium can reach the clutch cylinder 2 from the pressure port P via the port K _A. The opening cross sections at the two connections K _A and P are advantageously the same size. In this switching position 5, the web 38 closes the connection from the coupling connection K _A to the tank T. In the switching position 5 , there is a maximum opening speed of the coupling 1 . During the subsequent accelerating, depending on the driving program, the piston 35 is then moved into a throttle position in which the clutch 1 is closed at the closing speed corresponding to the driving program. In this case, the magnet 36 is energized less, so that the piston 36 is pushed ver under the force of the return spring 37 in the direction of the switching position 0.

Starting from the switching position 5, in which the magnet 36 is fully energized, the piston 35 , when the magnet 36 is less energized, reaches the switching position 3 via the switching position 4 ( FIG. 13). The piston 35 is in the switching position 3 so far ben that the coupling connection K _A with the tank connection T is connected ver. In addition, the connection between the Druckan circuit P and the port P _{G is} still open. The opening cross sections at the connections K _A and T are advantageously of the same size, which results in a maximum closing speed of the clutch 1 . While driving, the piston 35 remains in this switching position 3 when the clutch is closed.

So that the piston 35 retains this switching position, the magnet 36 must be constantly energized to prevent the piston 35 from closing force under the force of the return spring 37 closes the opening cross section at the tank connection T again.

FIGS. 11 and 12 show intermediate positions of the piston 36 when, for example, shifted from the position 0 (safety position) in the switching 4-position. Starting from the switch position 0, the piston 35 is pushed back against the force of the return spring 37 by energizing the magnet 36 . The web 44 first reaches a position in which the connection between the pressure port P and the port P _{G is closed} with zero overlap. The connection between the coupling connection K _A and the tank connection T is still closed in this switching position 1 by the web 43 .

When the piston 35 is moved further by the magnetic plunger 49 , the connection between the pressure port P and the port P _{G is opened} after a first partial stroke in the switching position 2. The web 43 is in this switching position 2 in such a position that the connection between the coupling connection K _A and the tank connection T is closed with zero overlap.

From the switching position 2 ( Fig. 12) the piston then reaches the switching position 3 already described ( Fig. 13), in which the connection from the pressure connection P to the connection P _{G is} opened and also the connection between the coupling connection K _A and the tankan closing T is open.

If the vehicle comes to a standstill with a gear engaged, for example in front of a traffic light, the energization of the magnet 36 is changed from a position control loop (not shown) in such a way that the two clutch disks of clutch 1 are only slightly pressed together. This position of the two clutch disks becomes achieved by adjusting the piston 36 to the control position according to switching position 4 (Figure 14). In this position, the pressure port P is opened with the port P _G , while the connection from the coupling connection K _A to the tank port T is closed by the web 38 with zero overdec tion. In this way it is ensured that the required relative position to each other in the clutch discs. If gas is released again from this position, the piston 36 is moved back into the switching position 3 according to FIG. 13.

The switch position 5 for opening the clutch 1 is characterized by the fact that the two flow cross sections at the pressure port P and at the clutch port K _{A are of the} same size, so that the clutch 1 is opened at maximum speed, for example in a corresponding driving program. With this position of the piston 35 , the clutch 1 can be opened at the maximum speed, based on the driving program. The described switching positions 0 to 5 are shown in the lower half in Fig. 16 Darge. A comparison with the known valve in the upper half of FIG. 16 shows that the piston 35 of the new valve 3 in the re gel position (switching position 4 according to FIG. 14) takes a different position than the piston 35 of the known valve. In the total stroke of the piston 35 of the valve 3 , the working stroke is integrated, which is smaller than the total stroke. The control position (switching position 4 GE according to Fig. 14) is offset from the control position of the known valve so that there is an asymmetrical stroke distribution in the valve 3 compared to the known valve.

At the port P _{G of} the valve 3 , the leaking oil valves 5 to 8 of the gear actuator 4 are connected ( Fig. 1). If the clutch 1 is closed, no gear can be engaged or removed who. The port P _G is separated from the pressure port P by the web 44 of the piston 35 . For all valves 5 to 5 , therefore, only a single leak in valve 3 is decisive. If valve 3 were missing, 5 to 8 leakage oil would occur on each of the valves. By interposing the valve 3 , the leakage oil losses are minimized. The opening connection between the connection P _G and the pressure connection P is opened within the partial stroke 1 ( FIG. 12), which is also carried out for the safety function. The working stroke of the piston 35 is thus not restricted by opening the connec tion between the ports P _G and P.

Figs. 2 to 5 show a constructional design of the supply unit Druckölversor. It has a housing 50 in which the tank 17 is housed, which is closed by a cover 51 . Below the tank 17 , the drain cock 24 is in the form of a drain screw, which is located in an externally accessible bore 52 of the housing 50 . The locking screw 24 is retracted up to a locking ring 53 serving as a stop, which is inserted into a groove in the wall of the bore 52 . The locking screw 24 has a narrow neck 54 which lies in a corresponding bore portion 55 of the housing 50 . The United screw 24 contains the safety valve 23 in the form of a check valve. It closes a transverse bore 56 in the neck 54 of the drain plug 24 .

On the side of the drain plug 24 opposite the tank 17 there are three locking pistons 57 which are spaced apart from one another in the housing 50 and of which only one locking piston is shown in FIG. 2. Therefore, in the following only the water a sealing piston is described in more detail. It is under the force of a compression spring 58 , which is supported on the bottom of a blind hole 59 of the housing 50 . Before assembling the Druckölver supply unit, the locking piston 57 is under the force of the compression spring 58 at a fixed in the blind hole 59 to blow 60 , which is sleeve-shaped and on the Innenwan extension of the blind hole 59 is present. The sleeve-shaped stop 60 has approximately half an axial length on the outside of an annular groove 61 which creates a flow connection between a bore 62 connected to the pump 18 and a bore 63 which is provided in an intermediate wall between the blind bore 59 and the bore section 55 .

A connection plate 64 is screwed onto the housing 50 and has the three connection points T, K _A and P _G. These three connection points are at the same height next to each other at a distance and are each formed by pieces of pipe 65 which are inserted through corresponding openings 66 in the connection plate 64 . The pipe sections 65 have a plug-in part 67 which is larger in the outside diameter and merges via a shoulder 68 into a bearing section 69 which is smaller in diameter. With him, the respective pipe section 65 lies against the inner wall of the opening 66 . The bearing section 69 is adjoined by a holding section 70 of smaller outer diameter, onto which a piece of hose 71 is pushed. In order to ensure a secure fit of the tube piece 71 on the holding section 70 , it is preferably designed with a wavy profile on its outside. In the area above the openings 66 , the connection plate 64 is provided with a threaded bore 72 into which an end-side threaded part 73 of the drain screw 24 is screwed.

The connection plate 64 is pre-assembled with the pipe pieces 65 . For assembly, the preassembled closure plate 64 is attached to the housing 50 . Here, the plug-in parts 67 of the pipe pieces 65 engage in the blind holes 59 . When inserted, the United piston 57 are moved by the plug-in parts 67 against the force of the Druckfe countries 58 ( Fig. 4). The plug-in parts 67 are provided at the free end with a tapered in the outer diameter shoulder 74 , which is designed so that it bears in the installed position ( FIG. 4) on the inner wall of the sleeve-shaped stop 60 . The plug-in parts 67 lie with a sealing ring 75 sealingly against the inner wall of the blind hole 59 . The drain screw 24 is screwed with its Ge threaded part 73 into the threaded bore 72 of the connecting plate 64 , whereby this is pulled firmly against the end face of the housing 50 . The drain plug 24 is supported with its head 76 on a circumferential radial shoulder surface 77 of the bore 52 . The approach 54 of the drain screw 24 is with a sealing ring 78 you tend to the inner wall of the reduced diameter Boh approximately 55 . It is expanded at the height of the transverse bore 63 in diameter, so that in the installed position of the drain screw 24 between its neck 54 and the wall of the Bohrungsab section 55, an annular gap 79 ( Fig. 4) is formed.

When the connection plate 64 is screwed on, a hydraulic connection from the gear actuator 4 via the hose pieces 71 and the plug-in parts 67 of the pipe pieces 65 is opened to a bore 80 in the housing 50 , which is connected to the connection P _{G of} the valve 3 . In the same way, the other connections K _A and T of the connection plate 64 are connected to corresponding bores in the housing 50 , to which the corresponding connections T and K _{A of} the valve 3 are connected.

The design described results in a very simple assembly of the pressure oil supply unit. The pipe sections 65 with the drawn-on hose sections 71 can be preassembled. With the drain screw 24 , the closure plate can be securely screwed to the housing 50 , the plug-in parts 67 of the pipe pieces 65 inevitably coming into their installation position in which they are connected to the corresponding connections of the valve 3 in the line described.

In Fig. 4 it is indicated by dash-dotted lines that the on circuit board 64 has three spaced-apart pipe sections with hose sections. As Fig. 1 shows, sitting in the Lei tung compounds of the closure piston to the ports of the valve 3 check valves 81 which open towards the valve 3. The locking pistons 57 are provided with a sleeve-shaped extension 82 ( FIG. 4), on the end face of which the extension 74 of the plug-in part 67 of the corresponding pipe section 65 lies sealingly. The wall of the sleeve-shaped extension 82 of the closure piston 57 is provided with at least one passage opening 83 , via which a line connection between the respective pipe section 65 and the respective connection of the valve 3 is made.

FIGS. 6 to 9 show a different fastening of the pipe sections 65 a of the connection plate 64 a. It has three receptacles 84 to 86 lying next to one another at a distance on the edge, which are open at the edge and have an approximately semicircular outline. The pipe sections 65 a are provided in the region of their plug-in parts 67 a with two circumferential, radially spaced flanges 87 and 88 , between which an annular groove 89 is formed. The outer diameter D of the flanges 87 , 88 is larger than the insertion width d into the respective receptacle 84 to 86 ( FIG. 7). The insertion width d is delimited by a part-circular shape, the edge 90 of a clip part 91 which is fastened on the side of the connecting plate 64 a facing the housing 50 a. The clip part 91 is advantageously made of plastic. The edge 90 forms a spring-like projection which engages in the annular groove 89 of the respective pipe section 65 a.

Fig. 7 shows the different stages when clipping the pipe pieces 65 a. Since the outer diameter D of the flanges 87 , 88 is greater than the insertion width d of the part-circular edge 90 , this is elastically widened when the pipe pieces 65 a are clipped in, until the edge 90 designed as a projection of this type engages in the groove 89 of the respective pipe piece 65 a . The pipe sections are held in the 84 to 86 clamped. So that the edge 90 of the clip part 91 can be elastically expanded, it has 90 recesses 92 , 93 in the region between the edges, which are open to the edge.

The housing 50 a has on its connecting plate 64 a facing the end face at the level of the bore portion 55 a a sleeve-shaped approach 94 through which the threaded part 73 of the drain screw 24 protrudes. The housing projection 94 is advantageously cylindrical and has an outer diameter which corresponds to the inner diameter of an opening 95 in the clip part 91 .

The connection plate 64 a is applied with the clip part 91 to the housing 50 a. In this case, the housing attachment 94 engages in the opening 95 in the clip part 91 and lies against the inner wall thereof. The pipe pieces 65 a are performed in accordance with the previous embodiment when attaching the connection plate 64 a in the blind holes 59 a. The locking piston 57 are pushed against the force of the Druckfe 58 in the manner described. The drain screw 24 is screwed with its threaded part 73 into the threaded bore 72 a of the connecting plate 64 a, which is thereby pulled firmly against the end face of the housing 50 a.

The housing 50 a is otherwise the same design as in the previous embodiment.

On the connection plate 64 , 64 a, the corresponding pipe pieces 65 , 65 a can be preassembled. The customer has to preassembled the end plate 64 , 64 a only on the housing 50 , 50 a and screw it with the drain screw 24 . When screwing the connection plate 64 , 64 a, the line connection from the valves 5 to 8 of the gear actuator 4 to the connections of the valve 3 is automatically produced by pushing back the closure piston ben 57 . Conversely, if the drain plug 24 is unscrewed, a connection from the pressure port P to the tank port T is opened so that the hydraulic medium can flow back directly into the tank 17 . Since the memory 19 is connected to the pressure port P of the valve 3 , the memory content can flow directly to the tank 17 when the connection to the tank port T is opened.

Instead of the flexible lines 71 , rigid lines can also be connected to the connection plate 64 , 64 a.

Since the safety valve 23 is built into the drain plug 24 , additional installation space and an additional housing are not required for this valve. The drain plug 24 thus has several functions. On the one hand, it is used to attach the connection plate 64 , 64 a to the housing 50 , 50 a. It is also used for draining the memory 19 . Finally, it can serve as a safety device for the memory 19 .

Claims (28)

1. Pressure oil supply unit for the motor vehicle sector, testify before preferably for automated manual transmissions of motor vehicles, with a valve which has a pressure connection, a tank connection and a work connection, the control cross sections of which can be closed by a piston which can be adjusted by a magnet against spring force and when the current is not applied Magnet separates the working connection from the pressure connection, characterized in that the piston ( 35 ) separates the working connection (K _A ) from the tank connection (T) in a safety position. 2. Unit according to claim 1, characterized in that the piston ( 35 ) closes the tank connection (T) with an overlap (Ü ₂ ). 3. Unit according to claim 1 or 2, characterized in that the valve ( 3 ) has a further Ar beitsanschluß (P _G ). 4. Pressure oil supply unit for the motor vehicle sector, testify before preferably for automated manual transmissions of motor vehicles, with a valve which has a pressure connection, a tank connection and a work connection, the control cross sections of which can be closed by a piston which can be adjusted by a magnet against spring force and when the current is not applied Magnet separates the working connection from the pressure connection, in particular according to one of claims 1 to 3, characterized in that the valve ( 3 ) has a further working connection (P _G ), and that the piston ( 35 ) in the safety position ensures the further working connection (P _G ) from the pressure port (P) separates. 5. Unit according to claim 4, characterized in that the piston ( 35 ) the Druckan connection (P) with an overlap (Ü ₁ ) from the other Arbeitsan connection (P _G ) separates. 6. Unit according to claim 5, characterized in that the overlap (Ü ₁ ) is smaller than the overlap (Ü ₂ ) when closing the tank connection (T). 7. Unit according to one of claims 1 to 6, characterized in that a coupling cylinder ( 2 ) of the motor vehicle is connected to the working connection (K _A ). 8. Unit according to one of claims 3 to 7, characterized in that valves ( 5 to 8 ) of a gear actuator ( 4 ) are connected to the further working connection (P _G ). 9. Unit according to claim 7 or 8, characterized in that to close the coupling ( 1 ) the connection from the pressure connection (P) to the further working connection (P _G ) and from the other working connection (K _A ) to the tank connection (T) opened is. 10. Unit according to claim 9, characterized in that the flow cross-sections at the other working connection (K _A ) and at the tank connection (T) are of the same size for a maximum speed of the clutch ( 1 ). 11. Unit according to one of claims 7 to 10, characterized in that to open the coupling ( 1 ) the connection from the pressure connection (P) to the further working connection (P _G ) and the other working connection (K _A ) is open. 12. Unit according to claim 11, characterized in that for a maximum opening speed of the coupling ( 1 ) the flow cross-sections at the pressure connection (P) and at the other working connection (K _A ) are the same size. 13. Unit according to one of claims 1 to 12, characterized in that the piston ( 35 ) in a control position opens the connection from the pressure connection (P) to the further working connection (P _G ) to the connection of a memory ( 19 ) to the valves ( 5 to 8 ) of the gear actuator ( 4 ), while keeping the other working connection (K _A ) closed. 14. Unit according to one of claims 1 to 13, characterized in that the valve ( 3 ) is housed in a housing ( 50 , 50 a). 15. Unit according to claim 14, characterized in that the housing ( 50 , 50 a) Connections se (P _G , K _A , T), which via a connecting part ( 64 , 64 a) with the valves ( 5 to 8 ) of the gear actuator ( 4 ) and with the hitch be cylinder ( 2 ) can be coupled. 16. Unit according to claim 14 or 15, characterized in that the connecting part ( 64 , 64 a) is a connecting plate on which in the housing-side connections (P _G , K _A , T) insertable parts ( 65 , 65 a) are provided . 17. Unit according to one of claims 14 to 16, characterized in that in the housing-side connections Sen (P _G , K _A , T) locking pistons ( 57 ) are mounted. 18. Unit according to claim 17, characterized in that the locking piston ( 57 ) when inserting the plug-in parts ( 65 , 65 a) against spring force into a position connecting the respective housing-side connection with the corresponding connection of the valve ( 3 ) are displaceable. 19. Unit according to one of claims 16 to 18, characterized in that the plug-in parts ( 65 , 65 a) are Rohrstüc ke, which are held in the connecting part ( 64 , 64 a). 20. Unit according to one of claims 15 to 19, characterized in that the plug-in parts ( 65 ) are held in openings ( 66 ) in the connecting part ( 64 ). 21. Unit according to one of claims 15 to 19, characterized in that the plug-in parts ( 65 a) in clips ( 84 to 86 ) are clipped. 22. Unit according to claim 21, characterized in that the receptacles ( 84 to 86 ) on egg NEM clip part ( 91 ) are provided which is attached to the connecting part ( 64 a). 23. Unit according to claim 21 or 22, characterized in that the receptacles ( 84 to 86 ) transverse to the longitudinal direction of the plug-in parts ( 65 a) are open. 24. Unit according to one of claims 15 to 23, characterized in that the connecting part ( 64 , 64 a) is held on the housing with at least one screw ( 24 ) accommodated in the housing ( 50 , 50 a). 25. Unit according to claim 24, characterized in that the screw ( 24 ) at the end has a threaded part ( 73 ) with which it can be screwed into a threaded bore ( 72 , 72 a) of the connecting part ( 64 , 64 a). 26. Unit according to claim 24 or 25, characterized in that a safety valve ( 23 ) is housed in the screw ( 24 ). 27. Unit according to claim 26, characterized in that the safety valve ( 23 ) in the line connection from a pump ( 18 ) to the tank ( 17 ). 28. Unit according to one of claims 24 to 27, characterized in that a connection from the memory ( 19 ) to the tank ( 17 ) is made by opening the screw ( 24 ).