EP2625433A1

EP2625433A1 - Apparatus for controlling a hydraulic accumulator of a hydraulic system

Info

Publication number: EP2625433A1
Application number: EP11754660.6A
Authority: EP
Inventors: Ruediger Block; Nils Steinbach; Wolfgang Rudolph; Werner Hess; Ianislav Krastev; Manfred Stachely; Helmut Schneider; Steffen Strauss; Uwe Kulow; Christof Ott
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2010-10-08
Filing date: 2011-09-08
Publication date: 2013-08-14
Also published as: DE102010042194A1; WO2012045547A1; US20130263948A1; CN103140687A

Abstract

Described is an apparatus (20) for controlling a hydraulic accumulator (10) of a hydraulic system (12), for example of a vehicle gearbox (14), having a valve device (26) by means of which an accumulator-side port (B) of the apparatus (20) can be connected to and separated from a system-side port (A), wherein the valve device (26) comprises at least one valve main stage (56), said valve main stage being arranged hydraulically between the accumulator-side port (B) and the system-side port (A) and being acted on in the opening direction by a load-exerting means, preferably the pressure prevailing hydraulically at the accumulator-side port (B), and comprises an electrically actuated control valve (52) which can connect the system-side port (A) to a control port (X), which acts in the closing direction of the valve main stage (56), of the valve main stage (56) and to the accumulator-side port (B), wherein at least a first restrictor (60) is arranged between the control valve (52) and the accumulator-side port (B).

Description

Description title

Device for controlling a hydraulic accumulator of a

Hvdrauliksvstems

State of the art

The invention relates to a device according to the preamble of claim 1.

From the market known so-called start-stop functions for

Motor vehicles, by means of which the internal combustion engine can be switched off automatically when the vehicle is stopped by a control unit. This can result in fuel savings ranging from about 3% to about 5%.

Automatic transmissions such as a stepped automatic transmission, a

Dual-clutch transmissions or continuously variable transmissions are generally hydraulically controlled and require a hydraulic pressure and a hydraulic volume flow for operation. This is from a

mechanical - that is driven by the internal combustion engine - provided pump, the pump by the linear dependence of

Volumetric flow of the rotational speed and because reserves reserves to account for the idle speed of the engine and a possibly high oil temperature is usually performed oversized.

A system pressure regulator adjusts a constant hydraulic pressure in the automatic transmission, and an excess amount of fluid is returned to a tank or reservoir. Solutions are known in which the pump is made mechanically variable (eg by means of an adjustment of the eccentricity of a vane pump), which can lead to fuel savings. When the internal combustion engine is stationary during the stop phase and the hydraulic pump is stationary, the transmission may no longer be supplied with sufficient pressure or flow. Since the hydraulic circuit has certain leaks, the clutches and brakes are brought by return springs in a non-pressurized (that is usually open) position.

When restarting the engine, it takes a certain time until the mechanical pump generates enough pressure again. This leads to a corresponding time offset until a starting torque can be transmitted via the clutches. On the other hand, can be undesirable

Momentum jumps result when the clutches uncontrollably close or slip. Furthermore, these couplings are usually not designed for the loads occurring.

To remedy this, an electrically demand driven oil pump can be used, which constantly or just before the start of the engine, the oil or hydraulic fluid in the gearbox complements. An alternative solution is the use of a memory component. This has the task shortly before and / or at the start of the internal combustion engine to deliver a missing amount of oil in the transmission to fill the lines and the gearbox or the clutches.

It is also known a solution in which a spring-piston accumulator - for example, with a memory size of about 100ml (milliliters) is mechanically rested during the stop phase in a filled state, and is charged during normal driving by the hydraulic pump. In this case, the charging time can not be influenced because of a filling throttle depending on the pressure of the pump shortly after the engine start (that is, at low speeds) fluid from the transmission hydraulic circuit flows into the memory.

During the stop phase of the internal combustion engine, a solenoid of a valve controlling the fluid exchange is energized. Before and during the restart of the internal combustion engine, when the speed increases continuously, the detent is released by the electromagnet is de-energized, whereby a hydraulic pressure and a suitable amount of fluid for the Gearbox be provided. In this case, the empty cavities of the hydraulic circuit are filled, so that the pressure build-up by the mechanical pump can be done quickly and the motor vehicle can start without a noticeable delay.

A general solution is the combination e.g. any one

Hydraulic accumulator (for example, gas piston accumulator, spring-piston accumulator, gas-membrane accumulator with barrier layer) in conjunction with an electro-hydraulic valve (such as a 2/2 way valve). This is the memory during normal driving charged with fluid by the transmission oil pump. During the stop phase, the reservoir stores the fluid and can return it to the transmission or hydraulic system shortly before and / or during the start-up phase.

There are high demands on the valve with regard to tightness,

Pollution of the fluid (medium), and to meet the required flow. For example, it may be required to achieve a flow rate of 30 liters per minute for a time of 200 ms (milliseconds). When loading the memory, it should also be noted that the volume flow is limited, for example to about 3 liters per minute, so that the pressure in the transmission system does not break through the "missing" volume flow or the mechanical transmission oil pump would have to be dimensioned larger, if necessary.

For example, the following documents are known from this field: DE 10 2006 041 899 A1, DE 10 2006 014 756 A1, DE 10 2006 014 758 A1, JP 10250402 A, US Pat. No. 5,293,789 A1, EP 1 265 009 B1, US 20050096171 A1 , EP 1 353 075 A2 and JP 2007138993 A.

Disclosure of the invention

The problem underlying the invention is solved by a device according to claim 1. Advantageous developments are specified in subclaims. For the invention important features can be further found in the following description and in the drawings, the features both alone and in different combinations for the Invention may be important, without being explicitly referred to again.

The invention has the advantage that a hydraulic accumulator of a hydraulic system, in particular in automatic transmissions, for carrying out a start-stop function of an internal combustion engine can be controlled filled and emptied, the space occupied, the wear and the susceptibility to contamination are low and an electric one

Energy consumption is low. In particular, the device may be designed so that during a stop phase of the internal combustion engine, no electrical energy for holding the hydraulic accumulator pressure is required. The device according to the invention operates reliably and inexpensively and can be manufactured comparatively easily. The invention is based on the consideration that a hydraulic accumulator of a hydraulic system, such as for industrial hydraulic applications or in automotive technology - such as for the engine oil circuit or the

Vehicle gearbox - should be filled and emptied in a controlled manner. This can also be referred to as a direction-dependent "volume flow control". For this purpose, a valve device according to the invention is used with an electromagnetically actuated control valve and a valve main stage which can be controlled thereby (for example in the form of a switching valve). In this case, an existing in the hydraulic system pressure or volume flow source

(For example, a mechanically driven pump) filling the

Memory.

The device comprises a memory-side connection and a

system-side connection. The valve main stage is arranged hydraulically between the memory-side connection and the system-side connection, and is preferably prevailing through the memory-side connection

Pressure applied in the opening direction. It is characteristic that the

hydraulic cross-section of the control valve can advantageously be significantly smaller compared to the large cross section of the main valve stage. The control valve can connect the system-side connection with a control connection of the valve main stage acting in the closing direction of the valve main stage and also with the memory-side connection. It is between the Control valve and the control terminal of the valve main stage on the one hand and the memory-side terminal on the other hand arranged at least a first throttle, which ensures a certain hydraulic separation between steuerseitigem and memory-side connection and thus a safe opening of the valve main stage with open control valve, and with the control valve open Gradual filling of the memory allows, when closed

On the other hand, the control valve and filled accumulator pass the pressure prevailing at the accumulator-side port to the control port of the main valve stage, thus ensuring a safe closing of the main valve stage. With this

Arrangement becomes a basic form for a hydraulically piloted

Valve device formed, which is also known as a "servo valve". As a result, by means of a comparatively small control valve, a comparatively large hydraulic volume flow can be controlled, wherein advantageously the pressure present in the hydraulic accumulator is utilized. The first throttle may also be designed as a diaphragm or as another hydraulic element which is suitable for throttling a hydraulic flow. A throttle has the advantage over a diaphragm that the volume flow

can be limited relatively independently of the temperature of the fluid.

The device may have at least three operating states depending on the direction of the pressure difference and the electrical drive signal of the

Have control valve. A first operating state allows the delivery of fluid from the system-side port to the storage-side port, that is, a hydraulic one connected to the storage-side port

Storage can be filled with fluid or "charged". A prerequisite for this is that the hydraulic pressure during this condition on the

system-side connection is greater than at the memory-side connection. The main valve stage in this case is in most configurations

closed, the control valve open. This limits the hydraulic

Cross section of the control valve and other hydraulic elements in the

Hydraulic path from the system-side connection to the memory-side connection the charging volume flow, which is generally desirable.

A second operating state relates to the "holding" of the hydraulic pressure to the storage-side connection or in the hydraulic Memory (after filling). Preferably, the hydraulic pressure at the memory-side connection is approximately the same or higher than at the system-side connection. This will be an at least temporary

Storage of fluid allows. It is important that, when the control valve is blocked, the hydraulic pressure at the control connection of the valve main stage corresponds approximately to the hydraulic pressure at the storage-side connection. This is achieved by the action of the first throttle. This results in both sides of a arranged in the valve main stage valve body in about the same hydraulic pressures. In this state, a - described below - spring, which acts in the closing direction of the main valve stage, cause a defined locking of the main valve stage. Preferably, the control valve is designed so that, for example, an electromagnet is de-energized while holding the hydraulic pressure and thus consumes no energy. In a third operating state, the hydraulic pressure at the

memory-side connection greater than at the system-side connection. Thus, with the valve main stage open, fluid can flow from the storage-side connection or the hydraulic accumulator back to the system-side connection. The hydraulic accumulator is thereby at least partially emptied. This operating state is for example at a restart of the

Internal combustion engine after a stop before.

According to the invention, the emptying of the hydraulic accumulator is carried out in a controlled manner by an actuation of the control valve, wherein the control valve is temporarily opened, and a pressure in a control region or at the control connection of the main valve stage is changed, preferably reduced. As a result, the main valve stage can subsequently open, as a result of which the accumulator-side connection and the system-side connection are hydraulically connected to a comparatively large flow cross-section.

Likewise, in some embodiments of the device, the delivery of fluid from the system-side connection to the storage-side connection, that is to say the filling of the hydraulic accumulator, can also be effected by a

Operation of the control valve to be controlled. In this case, the valve main stage remains locked, so closed the large hydraulic cross section, so that the flowing through the control valve in the hydraulic accumulator Fluid flow can be limited, and thus no inadmissible pressure drop occurs in the hydraulic system.

An embodiment of the device provides that the valve main stage comprises a spring acting in the closing direction. This allows a valve in the valve

Main stage sliding valve body and / or a displaceable piston are brought at any time in a defined position even at a low or no hydraulic pressure. In addition, by suitable design of the spring characteristics, the operating behavior of the valve main stage can be adapted to the respective requirements and hydraulic pressures.

Another embodiment of the device provides that they a

Includes check valve which is arranged parallel to the first throttle and blocks to the control valve. Building on the above

Basic form of the device can in the first operating state the

Open check valve when filling the hydraulic accumulator, so that in addition to the first throttle fluid with relatively little resistance can flow into the hydraulic accumulator. Thus, the filling can be done faster. The flow area of the throttle can thus be made smaller. This has an advantageous effect in the third operating state when driving the main valve stage, in which then the fluid pressure at the control connection of the main valve stage can drop comparatively quickly and severely. As a result, a desired valve lift and / or a switching behavior of the main valve stage can be increased or improved. Likewise, the control valve can build smaller.

A further embodiment of the invention - again based on the described basic form of the device - provides that it comprises a second throttle and a check valve, which are arranged to each other in series and generally parallel to the valve main stage, wherein the check valve to the system-side port locks. Accordingly, that can

Open the check valve if the hydraulic pressure at the system-side connection is greater than the hydraulic pressure at the memory-side connection. In this way - with a corresponding pressure difference - the hydraulic accumulator can be continuously filled via the second throttle, wherein the strength of the fluid flow substantially through the flow area of the second throttle is determined. In the second and third operating state of the device, the check valve locks to the system-side connection, and the emptying of the hydraulic accumulator, as described above, can be controlled via the main valve stage. An advantage of this embodiment is that for filling the hydraulic accumulator no activation is required and no electrical energy is consumed.

A further embodiment of the device provides that it comprises a second throttle and a check valve which are arranged parallel to each other and in total between on the one hand the control valve and the valve main stage and on the other hand the system-side connection. In this case, the check valve is arranged so that it locks in the direction of the memory-side terminal. The filling of the hydraulic accumulator is similar to the basic form of the device described above, with the difference that the fluid flow is additionally throttled via the second throttle. At the

Draining the hydraulic accumulator opens the check valve and the fluid flow is substantially unhindered across the system

Connection to the rest of the hydraulic system flow. A further embodiment of the device provides that between the

Control valve and the system-side connection a filter is arranged. Thus, any dirt particles in the fluid can be filtered before they can reach the control valve. Thereby, the reliability and the life of the device according to the invention can be further increased. Furthermore, by this arrangement of the filter, the function of

Device particularly little affected. The filter may for example be designed as a so-called "ring filter" and arranged to save space in the region of the control valve. Furthermore, it is provided that an opening cross section of the control valve is greater than a flow cross section of the first throttle. This ensures that the control of the valve main stage can be defined by the open control valve to empty the hydraulic accumulator.

For example, the valve main stage can open when a pressure applied by the hydraulic pressure at the control port to the valve body of the valve body.

Main stage acting force plus the force of the spring is smaller than one in the Opposite direction by the hydraulic pressure on the memory side

Connection caused force. The pressure at the control port depends on the ratio of the open control valve in the direction of

System-side connection flowing fluid quantity to the flowing from the memory-side terminal via the first throttle fluid amount.

The device builds easier when the first throttle is a channel in the

Valve body of the valve main stage, wherein the channel remains open when seating the valve body on a sealing seat. The channel is preferably designed as an axial bore in the valve body or in the piston forming the valve body. As a result, space can be saved and costs reduced.

An embodiment of the invention provides that the valve main stage has a valve body with a conical sealing portion. As a result, a surface pressure on the sealing portion can be reduced and the fatigue strength of the valve main stage can thus be increased.

Alternatively, it is provided that the valve main stage has a valve body with a spherical sealing portion. Thereby, the tightness of the valve main stage can be advantageously improved in the closed position. Preferably, the associated valve seat is made conical, so that the valve main stage is executed overall according to a ball-and-cone principle. Thus, the sealing effect of the valve main stage can be improved, and leaks can be reduced.

The valve main stage is easier to build when the valve body is integrally formed with a guide portion with which it is guided in a valve housing. As a result, the number of individual elements of the main valve stage can be reduced and costs reduced.

Alternatively, it is provided that the valve body and a guide portion, with which it is guided in a valve housing, are separate parts. As a result, the tasks "lead" and "densities" are advantageously divided into different parts of the valve main stage. These can thus be optimized separately, so that the function of the main valve stage can be improved. In addition, it is provided that a spring is braced between the guide section and the valve body. As a result, the moving elements of the valve main stage can be brought into a defined position at any time. In addition, by means of the spring, a tolerance compensation between the guide portion and the valve body in the radial direction, without the need for additional elements are required. Preferably, the spring is a compression spring.

The valve main stage is further improved when a damping spring or an element with corresponding damping material properties (damping piece) is arranged between the guide section and the valve body. This can be provided in a simple manner an axially acting damping, whereby the function of the main valve stage improved, the operating noise can be lowered, and the fatigue strength can be increased.

An embodiment of the invention provides that the main valve stage is designed as a pressure compensated slide valve. As a result, hydraulic forces acting on the piston or on the valve body in the axial direction can be substantially avoided, and the function of the main valve stage thereby improved.

A further embodiment of the invention provides that between the

Guide portion and the valve body, a stop element is arranged. Thus, a defined minimum distance between the guide portion and the valve body can be adjusted.

A still further embodiment of the invention provides that between the guide portion and the valve body an axially acting

Damping element is arranged, which can also limit an axial distance between the guide portion and the valve body. This can advantageously be set at the same time a minimum distance between the guide portion and the valve body, and also a hard stop of the valve body can be avoided on the guide portion.

Yet another embodiment of the invention provides that a

Opening cross-section of the control valve is smaller than an opening cross-section of Valve main stage. Thus, a fluid flow at a - controlled by the control valve - filled filling of the hydraulic accumulator can be set smaller than a fluid flow when emptying the hydraulic accumulator. A still further embodiment of the invention provides that a material of a sliding bearing, in which the guide portion can slide, in about a same thermal expansion coefficient as a material of the

Guide section has. This allows the main level of the valve to be switched particularly precisely, and it also minimizes any leakage losses.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

Figure 1 is a hydraulic system of an automatic transmission with a hydraulic accumulator;

Figure 2 shows a first embodiment of a device for controlling the

hydraulic accumulator;

FIG. 3A shows a second embodiment of the device;

FIG. 3B shows a further embodiment based on FIG. 3A;

FIG. 4 shows a third embodiment of the device;

Figure 5 shows a fourth embodiment of the device;

Figure 6 is a first schematic of the device in a sectional view;

Figure 7 is a second schematic of the device in a sectional view;

Figure 8 is a simplified schematic of a main valve stage in one

Section;

Figure 9 shows an embodiment of the device and the hydraulic accumulator in a sectional view; Figure 10 is a first schematic of a piston and a valve ball;

Figure 1 1 shows a second scheme of a piston and a valve ball;

Figure 12 is a third schematic of a piston and a valve ball;

Figure 13 is a fourth schematic of a piston and a valve ball;

Figure 14 is a functional diagram of the piston and the valve ball in a first state;

FIG. 15 shows the functional diagram of FIG. 14 in a second state;

FIG. 16 shows the functional diagram of FIG. 14 in a third state;

Figure 17 is an alternative to Figure 9 embodiment of the device in a sectional view;

Figure 18 is a first timing diagram for operating the device;

Figure 19 is a second timing diagram for operating the device;

Figure 20 is a third timing diagram for operating the device; and

Figure 21 is a schematic of a combined arrangement of a check valve and a throttle in a sectional view.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments. In many of the described modified embodiments, the description of the function as well as the device will only deal with the essential differences from the previous embodiment or the preceding embodiments.

Figure 1 shows a simplified diagram of an arrangement of a hydraulic accumulator 10 in a hydraulic system 12 of an automatic transmission 14 of a Not explained in detail motor vehicle. The hydraulic accumulator 10, which in the present case is an accumulator 10, is by means of a device 20, which will be explained in more detail below, and via a hydraulic

Connection 18 connected to the rest of the hydraulic system 16. The

Device 20 comprises a valve device 26 and can be actuated electromagnetically by a control and / or regulating device 21 of the motor vehicle by means of an output stage 22. This is shown symbolically by an arrow 24. The device 20 has a system-side connection A and a memory-side connection B for the exchange of fluid. The control and / or regulating device 21 may, for example, an engine control unit, a

Be the transmission control unit or another control device of the motor vehicle.

Further, in the hydraulic system 12 exemplified here, a hydraulic pump 28, a hydraulic filter 30 and a controller 32 for controlling the system pressure are arranged. The hydraulic pump 28 is fed from a reservoir 34, which is connected to an output of the regulator 32. A port 36 connects the described arrangement to the automatic transmission 14, which in the drawing of FIG. 1 is represented by a hydraulic control 38 and valves 40, clutches 42 and brakes 44 comprised thereof.

It can be seen that the hydraulic system 12 is a closed system. Accordingly, it may be necessary to keep a quantity and a pressure of the fluid therein within certain limits. In particular, in the case of an automatic transmission of a motor vehicle which can be operated in a start-stop mode, the amount and the pressure of the fluid can change particularly strongly and rapidly. The pressure accumulator 10 serves primarily to store and provide hydraulic pressure and a certain amount of fluid when the hydraulic pump 28 was switched off.

The device 20 and the hydraulic accumulator 10 are designed to allow an exchange of fluid between the hydraulic accumulator 10 and the rest of the hydraulic system 16, depending on an operating mode of the motor vehicle. In a normal driving operation of the motor vehicle works the

Hydraulic pump 28 and allows the hydraulic accumulator 10 with fluid to fill. In a stop operation of the motor vehicle, however, the hydraulic pump 28 does not work. Therefore, for example as a result of leaks, pressure losses in the hydraulic system 12 may occur. Shortly before and / or during a start phase of the internal combustion engine of the motor vehicle following the stop mode, fluid can be introduced into the remaining hydraulic system 16 from the hydraulic accumulator 10 by means of the device 20. This can be done comparatively quickly and with low energy consumption. If subsequently by the action of the

Hydraulic pump 28 a required operating pressure in the hydraulic system 12 has been reached, conversely, the hydraulic accumulator 10 can be refilled from the rest of the hydraulic system 16. This can be done comparatively slowly. The hydraulic accumulator 10 of FIG. 1 can be designed as a spring-piston accumulator, as a gas piston accumulator, or as a gas membrane accumulator with a barrier layer.

FIG. 2 shows the device 20 for controlling the hydraulic accumulator 10 of the hydraulic system 12 in a first basic embodiment. In the present case, the device 20 comprises a 2/2-control valve 52 ("pilot valve"), which is actuated by means of an electromagnet 54, and a valve

Main stage 56 having a first hydraulic control port X which is hydraulically connected to a port of the control valve 52. The control valve 52 and the valve main stage 56 together form the valve device 26. The memory-side terminal B of the device 20 is on the one hand with the

hydraulic accumulator 10 and on the other hand with the first control port X, which acts in the closing direction of the valve main stage 56, and a second hydraulic control port Y of the valve main stage 56, which in

Opening direction acts, connected, and the system-side terminal A of the device 20 is on the one hand with the rest of the hydraulic system 16 and

on the other hand hydraulically connected to the control valve 52 and the valve main stage 56. Furthermore, between the control valve 52 and dem

Control terminal X of the valve main stage 56 and the memory-side terminal B, a first throttle 60 is arranged. In a first operating state of the device 20, a hydraulic pressure at the system-side port A is greater than a hydraulic pressure at memory-side connection B. The solenoid 54 is not energized, the control valve 52 is thus closed. At the control terminals X and Y, the same relatively low pressure prevails. This may, for example, correspond to a normal initial driving operation of the motor vehicle as long as the hydraulic accumulator 10 is not or only partially filled with fluid. The

Valve main stage 56 is locked by the action of a valve spring 58.

If the electromagnet 54 is then energized, the control valve 52 can open so that the fluid can flow from the system-side connection A via the open control valve 52 and the first throttle 60 to the storage-side connection B.

Characterized the hydraulic accumulator 10 is filled until the pressure at the system-side port A is approximately equal to the pressure at the memory-side port B, or until the solenoid 54 is turned off and thus the control valve 52 is closed. The filling is thus controlled by the control valve 52, wherein the main valve stage 56 remains locked.

In a second operating state of the device 20, the hydraulic pressure at the system-side port A may be greater than, equal to or less than the hydraulic pressure at the accumulator-side port B. This can

For example, a normal driving or a stop phase of

Motor vehicle correspond. The electromagnet 54 is de-energized, the

Control valve 52 is closed. The valve main stage 56 is at the second control terminal Y by the pressure at the memory-side terminal B in

Acting opening direction, and acted upon by the same pressure via the first throttle 60 at the control port X in the closing direction.

In addition, the force of the valve spring 58 acts on the valve main stage 56 in the direction of rotation, which therefore remains locked. The amount of fluid stored in the hydraulic accumulator 10 is thus kept ready for any subsequent emptying operation.

In a third operating state of the device 20, the hydraulic accumulator 10 is at least partially filled, and the hydraulic pressure at the accumulator side port B is greater than the hydraulic pressure at the system-side port A. This may correspond for example to the stop phase of the motor vehicle, in which the hydraulic pump 28 does not work and as a result of leaks the

Pressure in the rest of the hydraulic system 16 may be comparatively low. If a starting phase of the internal combustion engine takes place in this state, the electromagnet 54 is energized shortly before and / or during the start, so that the control valve 52 opens. As a result of the connection of the system-side connection A to the first control connection X, the pressure drops at the latter, so that the main valve stage 56 is opened by the higher pressure prevailing at the second control connection Y (corresponding to the pressure prevailing at the control-side connection B).

The opening cross section of the control valve 52 is sized larger than the flow area of the first throttle 60, so with respect to the

Control port X flow more fluid than can flow, and thus the pressure at the first control port X remains low. As a result, the valve main stage 56 opens so that fluid can flow from the memory-side terminal B to the system-side terminal A via the valve main stage 56.

Subsequently, the hydraulic accumulator 10 is relatively quickly and at least partially emptied, whereupon the pressure in the rest of the hydraulic system 16 increases accordingly. This ensures that after the start of the internal combustion engine, the required hydraulic pressure for the operation of the rest of the hydraulic system 16 is present. The emptying of the hydraulic accumulator 10 ends when a pressure equalization has taken place between the accumulator-side connection B and the system-side connection A, or when the electromagnet 54 is switched off.

This process can be expressed by the following equation:

F _P + F _X + F _A + F _B <0; in which

F _F = force of the valve spring 58;

F _A ⁼ P _A * A _A = hydraulic pressure force at the main valve stage 56 at the system-side port A;

^F B = PB * ^A B = hydraulic pressure force at the main valve stage 56 am memory-side terminal B or at the second

Control terminal Y of the valve main stage 56;

F _x = ρ _χ · A _x = hydraulic pressure force at the main valve stage 56 at the first control port X of

Valve main stage 56; where "p" are the respective hydraulic pressures and "A" are the respective hydraulically effective areas. The signs of the magnitudes are chosen so that when the sum shown in the formula is less than zero, the main valve stage 56 opens.

It is understood that the application described in FIG. 2 is exemplary in a motor vehicle, and the device 20 is also used in other - stationary or mobile - hydraulic systems 12 in which an exchange of fluid in a hydraulic accumulator 10 is to be controlled can be.

FIG. 3A shows, based on the representation of FIG. 2, a further one

Embodiment of the device 20, in which a check valve 62 is arranged parallel to the first throttle 60, wherein the check valve 62 for

Control valve 52 locks out. In addition, a filter 64 is arranged in the hydraulic connection between the system-side port A and the control valve 52.

It can be seen that in the first operating state when filling the

hydraulic accumulator 10, the check valve 62 can open, so that in addition to the first throttle 60 fluid flows into the hydraulic accumulator 10 with low flow resistance. This makes it possible to perform the first throttle 60, in comparison to the device 20 according to the figure 2, with a smaller flow cross-section. The filling can be done thanks to the

Check valve 62 take place relatively quickly, and - depending on the hydraulic pressure difference - essentially of the

Opening cross section of the control valve 52 limited.

If, in the third operating state, the hydraulic accumulator 10 is at least partially emptied, in order to additionally supply the remaining hydraulic system 16 with fluid fill, the result is a similar behavior of the device 20, as described above. The check valve 62 is locked. For the device 20 of Figure 3A, it is also necessary that the opening cross section of

Control valve 52 is sized larger than the flow cross-section of the first throttle 60, so that with respect to the control port X flow more fluid than can flow. As a result, the pressure in the control area remains so low that the main valve stage 56 can open. The throttle 60 may be made comparatively small. This results in additional advantageous for the device 20 of Figure 3A

Properties or constructive degrees of freedom with respect to the figure 2. First, the filling of the hydraulic accumulator 10 when opening the check valve 62 can be done faster. On the other hand, in the third operating state when emptying the hydraulic accumulator 10 because of the smaller flow cross-section of the first throttle 60, the fluid pressure at the

Control terminal X or in the control area of the valve main stage 56 may be comparatively low. As a result, a desired valve lift and / or a switching behavior of the main valve stage 56 can be increased or improved. Likewise, the control valve 52 can build smaller, and the

Dimensioning of the main valve stage 56 can be designed to meet production requirements.

In addition, the check valve 62 and the throttle 60 may be designed as a common element, for example by means of an axial bore or groove in a valve body or in a valve seat of the

Check valve 62.

FIG. 3B shows an embodiment of the invention based on FIG. 3A

Device 20. In addition to Figure 3A, the device 20 of Figure 3B in the hydraulic connection between the control valve 52 and the

Filter 64 an additional check valve 63 and a to the additional check valve 63 in parallel throttle 65. The check valve 63 may lock to the system-side port A. This results in further possibilities to the between the system-side terminal A and the control terminal X of the valve main stage 56 in a respective Operating state resulting volume flows or pressure differences to influence or adjust.

FIG. 4, again based on the representation of FIG. 2, shows a further embodiment of the device 20, in which a hydraulic connection parallel to the valve main stage 56 is arranged between the system-side connection A and the memory-side connection B, which second throttle 66 and a check valve 68 arranged in series therewith, which blocks to the system-side port A, comprises.

It can be seen that when the hydraulic pressure at the system-side port A is greater than the hydraulic pressure at the storage side

Port B, the check valve 68 can open. In this way - with a corresponding pressure difference - the hydraulic accumulator 10 via the second throttle 66 continuously and regardless of the position of

Control valve 54 are filled, wherein the strength of the fluid flow through the flow area of the second throttle 66 is limited. Actuation of the control valve 52 is therefore not required.

In the third operating state of the device 20, the check valve 68 is locked, and the emptying of the hydraulic accumulator 10 takes place as described above in FIG.

FIG. 5, again based on the representation of FIG. 2, shows a further embodiment of the device 20 in which, in series with the system-side connection A, a parallel connection of the second throttle 66 and the second

Check valve 68 is arranged, wherein the check valve 68 blocks to the memory-side terminal B out.

For reasons of uniform representation, in the figure 5, the system-side port A is further defined at the hydraulic connection of the control valve 52 and the valve main stage 56, and it is in the drawing of Figure 5 in addition an interface A1 below the second throttle 66 and of the check valve 68 defined in the direction of the rest of the hydraulic system 16. In the present case, the device 20 thus also includes the interface A1. In the first operating state of the device 20, the filling of the hydraulic accumulator 10 is similar to the representation of Figure 2, with the difference that the fluid flow is additionally throttled via the second throttle 66. In the third operating state of the device 20, the emptying of the hydraulic accumulator 10 takes place again in a similar way to FIG. 2, wherein the check valve 68 opens and the fluid flow to the system-side port A can flow unhindered.

FIG. 6 shows an embodiment of the device 20 together with the hydraulic accumulator 10 in a simplified sectional representation. At the top

Part of the drawing, the hydraulic accumulator 10 is partially shown, which can exchange fluid with the rest of the hydraulic system 16 via the system-side port A in the right area of the drawing. The hydraulic reservoir 10 is closed on all sides and has only the memory-side terminal B.

In the lower part of the drawing, a housing 70 is shown, the

essential elements of the device 20 comprises. A valve body 72, which is rigidly coupled to a piston 74 via a piston rod 76, is vertically displaceable in FIG. 6 in a fluid-tight guide 78. In the lower right-hand corner of the drawing, the control valve 52 which can be actuated by the electromagnet 54 is arranged, which can block or open a hydraulic connection 80 between the system-side connection A and a control region 82 of the valve main stage 56 belonging to the control connection X. In the de-energized state, the control valve 52 is locked by the force of a coil spring (not numbered). The first throttle 60 is arranged in the left region of the drawing of FIG. 6 in a further hydraulic connection 84 between the hydraulic accumulator 10 and the control region 82.

In the drawing, the valve body 72 has an upper end position in which it forms an opening of the hydraulic accumulator forming the accumulator-side port B.

10 closes by means of an annular sealing element 86. The valve spring 58 is disposed between the piston 74 and a lower portion of the housing 70 in the drawing so as to urge the piston 74 in the drawing upward in the closing direction of the valve main stage 56. A fluid channel 88 connects an upper pressure chamber 90 of the piston 74 in the drawing with the system-side connection A and allows a corresponding

Pressure compensation.

In the first operating state of the device 20, a hydraulic pressure at the system-side port A is greater than a hydraulic pressure at

memory-side connection B. If the electromagnet 54 by means of two

Power supply lines 92 energized, then the control valve 52 opens the

hydraulic connection 80, so that fluid from the system-side port A to the control port X and the control portion 82, and from there via the further hydraulic connection 84 and the first throttle 60 in the

hydraulic storage 10 can flow. As a result, the hydraulic accumulator 10 is filled as long as the electromagnet 54 is energized. After the end of the energization blocks the control valve 52, whereupon the pressure in the control region 82 can assume approximately the pressure of the located in the hydraulic accumulator 10 fluid.

In the second operating state of the device 20, that in the

stored hydraulic fluid 10 for any subsequent emptying, the electromagnet 54 is not energized.

In the third operating state of the device 20, the hydraulic accumulator 10 is at least partially filled, and the hydraulic pressure at the accumulator side port B is greater than the hydraulic pressure at the system-side port A. Wrd the electromagnet 54 is energized, so from the control region 82 fluid over the hydraulic connection 80 to the system-side port A flow. Subsequently, the pressure in the control portion 82 decreases, so that the upward in the drawing hydraulic force in the control portion 82 is smaller than the downward in the drawing hydraulic force on the valve body 72 at the memory-side terminal B. Then opens the valve main stage 56, whereupon fluid can flow from the hydraulic accumulator 10 to the system-side port A, so that the hydraulic pressure in the rest of the hydraulic system 16 can rise.

It is conceivable to supplement the device 20 of Figure 6, for example according to the scheme of Figure 4, by a second throttle 66 and a check valve 68, and thus - under appropriate pressure conditions - a permitting continuous "passive" filling of the hydraulic accumulator 10. This is not shown in FIG.

FIG. 7 shows a further embodiment of the device 20 as

"pilot-operated" spool valve 95. In contrast to Figure 6, the piston

74 designed as a so-called "spool", wherein the hydraulic connection 84 is embodied in an axial channel 93 of the piston 74, in which also the throttle 60 is arranged. The piston 74 is horizontally displaceable in the drawing of Figure 7 and has an annular groove 94, by means of which the valve main stage 56 is a hydraulic connection between the system-side terminal A and the

memory side terminal B can produce. The annular groove 94 is sealed on both sides by means of annular grooves (without reference numeral) in the outer circumferential surface of the piston 74 arranged annular sealing elements 86. In the

Drawing is the piston 74 - supported by the valve spring 58 - struck on a front-side annular stop 96. The stop 96 encloses a second control terminal Y forming fluid space 98 which is connected via a hydraulic connection 100 to the memory-side terminal B.

In the second operating state of the device 20, in which the hydraulic pressure at the system-side port A is greater than the hydraulic pressure at the accumulator-side port B, the piston 74 is struck on the stop 96 and the valve main stage 56 is locked. The control valve 52 is locked by the force of a coil spring (not shown).

When the electromagnet 54 is energized in the first operating state, the control valve 52 opens so that fluid, similar to FIG. 6, is removed from the system-side connection A via the hydraulic connection 80, the control region 82

Throttle 60, the hydraulic connection 84, the fluid space 98 and the hydraulic connection 100 can flow to the storage-side port B, so that the memory is filled.

In the third operating state of the device 20, the electromagnet 54 is again energized. Thereupon, the pressure in the control region 82 may decrease, so that the piston 74, because of the memory-side terminal B (or the second control port Y) of higher pressure with respect to the system-side port A (or the first control port X), against the force of

Valve spring 58 can be moved in the drawing to the left. In this case, through the annular groove 94, a hydraulic connection between the

memory-side terminal B and the system-side terminal A produced.

The valve main stage 56 is thus opened with a comparatively large cross section until a pressure equalization between the hydraulic accumulator 10 (not shown) and the rest of the hydraulic system 16 (also not shown), or until the solenoid 54 is turned off.

Also, as in FIG. 6, it is conceivable to supplement the device 20 with a second throttle 66 and a check valve 68, and thus - with appropriate pressure ratios - to allow a continuous "passive" filling of the hydraulic accumulator 10. This is not shown in FIG.

FIG. 8 shows a further embodiment of the main valve stage 56 in a greatly simplified sectional view. In the present case, the main valve stage 56 is designed essentially rotationally symmetrical with respect to a longitudinal axis 101.

Shown are a plurality of sections of the housing 70, which, among other things, the piston 74, the valve spring 58 and the control area 82 enclose.

The piston 74 is vertically displaceable in the drawing of Figure 8. An upper end section of the piston 74 in FIG. 8 forms the valve body 72, which is conical in FIG. In the present case, the piston 74 is in an uppermost position in the drawing, so that the valve body 72 is pressed against a valve seat 102. As a result, the system-side connection A is hydraulically separated from the storage-side connection B, and thus the main valve stage 56 is blocked.

In a lower region in the drawing, there is the control region 82, which can exchange fluid via the control connection X. At a higher pressure on the memory-side terminal B with respect to the system-side port A, the main valve stage 56 remains initially locked, as by means of the throttle 60, which is designed here as an axial channel 93 in the piston 74, a pressure equalization on both sides of the piston 74 can take place as long as there is no exchange of fluid via the control port X, and the piston 74 is pushed by the force of the valve spring 58 in the direction of the closed position to the top.

The operation of the main valve stage 56 together with the - not shown in the drawing of Figure 8 - control valve 52 corresponds to

Essentially Figures 6 and 7, as already described above.

Figure 9 shows one of the control and / or regulating device 21 of

Motor vehicle electrically operated device 20, which controls the access to the hydraulic accumulator 10, in a sectional view. The not shown in the drawing upper part of the hydraulic accumulator 10 is closed pressure resistant. The hydraulic arrangement of the elements arranged therein as well as the mode of operation essentially correspond to the device 20 shown in FIG.

The device 20 comprises the housing 70, in which a number of elements are arranged. In a lower portion in the drawing and from left to right, the device 20 includes, inter alia, the following elements: a plug 104, an electrical contact 106, and the solenoid 54, which can operate the control valve 52. The control valve 52 comprises a valve ball 108 arranged in an armature 107 and a sealing disk 110. In the lower right-hand area of the drawing, the main valve stage 56 is arranged. In a fluid space 1 12, the piston 74 by means of a sliding bearing 1 13 13 slidably disposed in the direction of the longitudinal axis.

In the central region of the drawing of FIG. 9, the system-side connection A is arranged on the left, which is structurally integrated with the plug 104 in a cover 1 14. A channel 1 16 connects the system-side port A, inter alia, with the valve main stage 56. The hydraulic connection 80 connects the channel 1 16 with the control valve 52. For this purpose, two in the housing 70 with respect to the longitudinal axis 101 transversely running bores are present are caulked fluid-tight by means of sealing balls 118 at outer portions of the housing 70. Similar to FIG. 8, in FIG. 9 the first throttle 60 is designed as an axial passage 93 by means of a longitudinal bore in the piston 74. The valve spring 58 is disposed in a cylindrical cavity of the piston 74 and pushes the piston 74 in the drawing to the right against the conical valve seat 102. An associated sealing portion 103 on the piston 74 has an approximately hemispherical geometry.

Likewise, a valve spring (without reference numeral) of the control valve 52 pushes the armature 107 together with the valve ball 108 without energizing the

Electromagnet 54 in the direction of the sealing disc 110, so that the control valve

52 can close. If the solenoid 54 is energized, the armature 107 is attracted by a magnetic core 1 19, so that the valve ball 108 is lifted from the sealing disc 1 10, and thus the control valve 52 opens. The device 20 of Figure 9 has essentially three main leakage paths. First at the sealing seat of the control valve 52, secondly at the valve seat 102 of the valve main stage 56, and thirdly via the formed between the piston 74 and the sliding bearing 1 13 annular gap. The gap can be as a

Gap seal be performed, with a radial clearance of, for example, +/- 20 μηι may be suitable. Preferably, the piston 74 and the plain bearing

1 13 similar thermal expansion coefficients and are made of steel or sintered bronze. In addition, the piston 74 in the cylindrical cavity for receiving the spring 58 on a paragraph with which the spring 58 is guided and at the same time protected against overloading.

The apparatus 20 illustrated in FIG. 9 can assist the already mentioned start-stop function of the internal combustion engine of the motor vehicle by virtue of a fluid exchange between the hydraulic system 12 of the motor vehicle

Automatic transmission 14 and the hydraulic accumulator 10 can be performed controlled.

FIG. 10 shows a schematic sectional view in a partial sectional view

Embodiment of the piston 74 of the valve main stage 56. The illustrated elements are substantially rotationally symmetrical to the longitudinal axis 101 executed. In the present case, the piston 74 comprises a guide portion 120, which can slide in the sliding bearing 113. In the guide portion 120 is a Stop element 122 is arranged, which has a stop surface 124 to which a valve ball 126 can strike. The valve spring 58 is arranged radially around the stop element 122.

It can be seen that, unlike the piston 74 of FIG. 9, the functions "guiding" and "sealing" are subdivided into separate elements, namely the guide section 120 and the valve ball 126. As a result, tolerances can be compensated and the function of the main valve stage 56 can be improved. The stop element 122 can reduce the operating noise of the valve main stage 56 and limit the opening cross-section of the main valve stage 56 with appropriate design. In contrast to the piston 74 of FIG. 9, however, the arrangement according to FIG. 10 has no longitudinal bore and thus no integrated first throttle 60.

FIG. 11 shows a further embodiment of the piston 74 in a sectional view. The guide portion 120, which can slide in the sliding bearing 1 13 in the direction of arrow 128, is in the present case designed as a cylindrical sleeve 120. In the drawing on the left, the sleeve 120 has an opening through which the valve spring 58 can exit and, for example, be supported on a section of the housing 70 or the sealing disk 110. The plain bearing 1 13 and other arranged in the vicinity of the piston 74 elements or housing sections are not shown in Figure 11.

It can be seen that the sleeve 120 acts on the valve ball 126 only in the direction of the arrow 128, so that the valve ball 126 can have a clearance perpendicular to the arrow 128. As a result, the seating of the valve ball 126 on the valve seat 102, which is not shown in FIG. 11, can be improved.

FIG. 12 shows a further embodiment of the piston 74 in one embodiment

Sectional view. The guide portion 120 is in turn designed as a cylindrical sleeve 120 which opens in the drawing to the right to the valve ball 126 out, the valve spring 58 is supported on an inner region of the sleeve 120 and can press directly on the valve ball 126. The remaining characteristics of the piston 74 are comparable to FIG. FIG. 13 shows a further embodiment of the piston 74, based on FIG. 10. In addition to FIG. 10, a damping spring 130 is arranged in the direction of the valve ball 126 in an end-side recess of the stop element 122. Thereby, the function of the piston 74 and the valve main stage 56 can be further improved.

FIG. 14 shows the piston 74 of the main valve stage 56 in the embodiment according to FIG. 10 together with the elements surrounding the piston 74 in a partial sectional illustration.

Because the piston 74 and the valve ball 126 has no bore in the direction of the longitudinal axis 101, the arrangement of Figure 14 in the upper left of the drawing a hydraulic connection 83 with a - not shown in the figure 9 check valve 134, through the Fluid exchange can be made to the memory-side terminal B.

Shown in Figure 14 is a ground state in which the piston 74 is pressed in the drawing to the left against the sealing disc 1 10, and the

Valve ball 126 is pressed to the right on the valve seat 102. This is indicated in the drawing by arrows. By means of the valve spring 58 it is achieved that the elements of the main valve stage 56 can assume a defined position in each operating state.

FIG. 15 shows the main valve stage 56 of FIG. 14 during filling of the hydraulic accumulator 10, not shown in the drawing, and in the case of FIG

subsequent holding of the fluid pressure built up in the hydraulic accumulator 10. The elements of the valve main stage 56 correspond to those of Figure 14, so that their reference numerals for the sake of simplicity are not repeated here.

During filling, the control valve 52 (not illustrated) is opened so that fluid can flow into the control region 82 of the piston 74 or the guide section 120 via the control connection X. The piston 74 presses by means of

Stop element 122 on the valve ball 126 and supports the sealing effect on the valve seat 102nd In holding the fluid pressure in the hydraulic accumulator 10, the control valve 52 (not shown) is closed. The elements retain the position shown in FIG. FIG. 16 shows the main valve stage 56 of FIG. 14 when emptying the hydraulic accumulator 10 to dispense fluid into the rest of the hydraulic system 16. The (not shown) control valve 52 is open, so that the valve ball 126 and also the piston 74 are pressed in the drawing to the left as a result of acting on the valve ball 126 from the memory side port B hydraulic pressure, so that the main valve stage 56th opens and fluid can flow in the direction of a line 132 from the memory-side terminal B to the system-side terminal A.

Figure 17 shows a further embodiment of the device 20 - based on the illustrations of Figures 14 to 16 - in a sectional view. The one in the left

Area of the drawing illustrated elements, in particular the plug 104, the electrical contact 106, the solenoid 54 and the control valve 52 substantially correspond to the device 20 of Figure 9. Reference is made to the description there.

The piston 74 and the guide portion 120, the

Stop element 122, the valve spring 58 and the valve ball 126 correspond to the arrangement according to FIG. 10. The control region 82 of the valve main stage 56 is shown in FIG. 17 with the accumulator-side connection B via the hydraulic connection 83 and via a check valve 134 arranged therein to the control area 82 locks out, connected. The check valve 134 comprises a valve ball 136 and a valve spring 138. The connection of the control valve 52 facing away from the control port X is connected to the system side

Port A is connected via a hydraulic connection 80 and an annular filter 64 for filtering the fluid.

The function of the main valve stage 56, in particular with respect to the

Guide portion 120 and the valve ball 126, corresponding to the representations of Figures 14 to 16. The valve ball 126 is a standard component and is guided in the present case by extending in the direction of the longitudinal axis 101 webs in the housing 70. The webs are indicated in the drawing only. Hereinafter, some possible structural configurations and / or alternatives of the device 20 are explained in more detail. For example, that can

Housing 70 may be injection molded from plastic, such as a plastic of the type PA66GF30. The sliding bearing 1 13 is made for example of a material "BP25" or "PTFE" in an injection molding process, and can be pressed into a portion of the housing 70. The valve ball 126 can along in

Housing 70 sprayed guides are performed. The guide portion 120 may be made of steel, for example, and ground on the surfaces subject to sliding friction, for example by means of a so-called "center-less" method. In this case, a fit accuracy of, for example, +/- 20 μηι can be achieved.

Furthermore, for example, in the device 20 according to the embodiment of FIG. 3A, the check valve 62 with integrated first throttle 60 can be pressed into the hydraulic connection 84 of FIG. 17. In this case, a disc of the check valve 62, which causes the blocking of the check valve 62 in place of a valve ball 136, are produced as a stamped-stamped part.

Furthermore, the sealing disc 110 made of plastic in a

Injection molding, where appropriate, the annular filter 64 may be pressed or pressed into or on the sealing disc 110.

Additionally or alternatively, a sealing weld can also be carried out by means of an ultrasonic method, a rubbing method or a laser welding method. The control valve 52 may be press fit into a portion of the housing 70 and / or a portion of the solenoid 54.

Furthermore, the cover 1 14 may be made of a same material as the housing 70, and attached thereto by pressing or locking. Additionally or alternatively, the lid 1 14 also by means of a

Ultrasonic method, a rubbing method or a laser welding method to be attached to the housing 70. This may be necessary, for example, if complete tightness is required. Furthermore, for the memory-side terminal B, a standardized interface suitable for a present design of the hydraulic accumulator 10 can be used. The hydraulic reservoir 10 may be pressed or latched onto the device 20, for example.

Furthermore, the valve spring 58, the first throttle 60, the second throttle 66 and the stopper 122 depending on requirements of the

Hydraulic system 12 and / or the automatic transmission 14 are dimensioned. In addition, the strength and / or duration of the driver 142 may depend on characteristics of the control valve 52 and / or requirements for

Operation of the automatic transmission 14 can be selected. In addition, by suitable design of the elements of the device 20, the fluid flows, the hydraulic pressures and / or the filling amount of the hydraulic accumulator can be flexibly taken into account, in particular with respect to a start-stop function of the internal combustion engine.

FIGS. 18 to 20 show three timing diagrams for explaining the function of the device 20 according to FIG. 17, whereby also the ones shown there are shown

Elements is referred to. The time diagrams are plotted over a time axis t and have the same time scale to each other.

Figure 18 shows a diagram with a delivery pressure 140 of the hydraulic pump 28, and a drive 142 of the control valve 52. At a time t1, the hydraulic pump 28 begins to promote, after which

Delivery pressure 140 increases and then settles on an operating pressure 144. At a time t2, the solenoid 54 of the control valve 52 is energized, so that fluid from the system-side port A via the open control valve 52 in the control region 82 of the main valve stage 56 can flow. Subsequently, the check valve 134 opens, so that the fluid can continue to flow to the storage-side port B and thus fill the hydraulic accumulator 10.

At a time t3, the energization of the electromagnet 54

switched off. Subsequently, the control valve 52 blocks. Subsequently, the hydraulic pump 28 is turned off, for example in a stop phase of Internal combustion engine. At a time t4, the delivery pressure 140 is zero, and the hydraulic pressure in the hydraulic system 12 becomes smaller, for example because of leakages.

From a time t5 and up to a time t6, the control 142 of the control valve 52 is effected by energizing the electromagnet 54 for a comparatively short period of time in which fluid can flow from the hydraulic accumulator 10 back into the rest of the hydraulic system 16 at a comparatively high flow rate.

FIG. 19 shows at the same time as FIG. 18 a deflection 146 of the valve ball 126 and a deflection 148 of the piston 74 or of the guide section 120 in the direction of the longitudinal axis 101. A reference line 150 means seating on the valve seat 102, and with respect to the valve ball 126 for the piston 74 sitting on the left in the drawing of Figure 17 stop on the

Sealing disk 1 10.

FIG. 20 shows, at the same time as FIGS. 18 and 19, a reservoir pressure 152 in the hydraulic reservoir 10, which in the present case is designed as a piston-spring reservoir, and a volume flow 154 characterizing the flow velocity. The positive value range above a zero line 156 means for the hydraulic flow Memory 10 one according to the

Storage pressure 152 stored amount of fluid, and for the volume flow 154, a drainage of fluid from the hydraulic accumulator 10th

By a comparison of Figures 18 to 20, the operation of the device 20 in the three operating states "filling", "hold" and "emptying" can be seen.

FIG. 21 shows an embodiment, suitable for FIG. 5, of a combined arrangement 158 of the second throttle 66 and of the check valve 68. A valve housing 159 comprises the system-side connection A and the

Interface A1 in the direction of the rest of the hydraulic system 16.

In the valve housing 159, the valve body 72 is arranged in the form of a conical disk, which in the direction of a longitudinal axis 162 by means of a valve spring 164 can be pressed onto a conical valve seat 166. The valve body 72 has an axial aperture 168, through which fluid can flow even in a locked valve. A flow cross section of the orifice 168 limits a possible fluid flow.

Claims

Device (20) for controlling a hydraulic accumulator (10) of a hydraulic system (12), for example of a vehicle transmission (14), with a valve device (26) which has a memory-side connection (B) of the device (20) with a system-side connection (A ) and can separate from it, characterized in that the valve means (26) at least one valve main stage (56) which hydraulically between memory side terminal (B) and systemseitigem terminal (A) is arranged and by a biasing means, preferably the hydraulic on the memory-side terminal (B) prevailing pressure, is acted upon in the opening direction, and an electrically operated

Control valve (52) comprising the system-side terminal (A) acting in the closing direction of the valve main stage (56)

Control terminal (X) of the valve main stage (56) and the memory-side terminal (B) can connect, wherein between the control valve (52) and the memory-side terminal (B) at least a first throttle (60) is arranged.

Device (20) according to claim 1, characterized in that the valve main stage (56) comprises a spring acting in the closing direction (58).

Device (20) according to one of the preceding claims, characterized in that it comprises a check valve (62), which is arranged parallel to the first throttle (60) and blocks the control valve (52) out.

Device (20) according to one of claims 1 or 2, characterized

characterized in that it comprises a second throttle (66) and a check valve (68) arranged in series with each other and generally parallel to the valve main stage (56), the check valve (68) blocking the system side port (A) , Device (20) according to one of claims 1 or 2, characterized

characterized in that it comprises a second throttle (66) and a check valve (68), which are arranged parallel to each other and in total between on the one hand the control valve (52) and the valve main stage (56) and on the other hand, the system-side port (A).

Device (20) according to one of the preceding claims, characterized in that between the control valve (52) and the

system-side connection (A) a filter (64) is arranged.

Device (20) according to at least one of the preceding claims, characterized in that an opening cross section of the control valve (52) is greater than a flow cross-section of the first throttle (60).

Device (20) according to at least one of the preceding claims, characterized in that the first throttle (60) is a channel (93) in a valve body (72) of the valve main stage (56), wherein the channel (93) upon seating of the Valve body (72) remains open on a sealing seat (102).

Device (20) according to one of the preceding claims, characterized in that the valve main stage (56) has a valve body (72) with a conical sealing portion (166).

Device (20) according to one of claims 1 to 8, characterized

characterized in that the valve main stage (56) comprises a valve body (72) with a spherical sealing portion (103).

1 1. A device (20) according to any one of claims 9 or 10, characterized

characterized in that the valve body (72) integral with a

Guide portion (120), with which this is guided in a valve housing (70) is formed.

12. Device (20) according to any one of claims 9 or 10, characterized

characterized in that the valve body (72) and a guide portion (120) with which it is guided in a valve housing (70) are separate parts.

13. Device (20) according to claim 12, characterized in that between the guide portion (120) and the valve body (72) a spring (58) is braced.

14. Device (20) according to claim 13, characterized in that between the guide portion (120) and valve body (72) a damping spring (130) is arranged.

15. Device (20) according to one of claims 1 to 8, characterized

characterized in that the valve main stage (56) is designed as a slide valve (95).

16. Device (20) according to claim 12 or 13, characterized in that between the guide portion (120) and the valve body (72) a stop element (122) is arranged.

17. Device (20) according to claim 12 or 13, characterized in that between the guide portion (120) and the valve body (72) an axially acting damping element is arranged, which also has an axial distance between the guide portion (120) and the

Limit valve body (72).

18. Device (20) according to at least one of the preceding claims, characterized in that an opening cross-section of the control valve (52) is smaller than an opening cross-section of the valve main stage (56).

19. Device (20) according to one of claims 11 to 14 or 16 to 18,

characterized in that a material of a sliding bearing (1 13), in which the guide portion (120) can slide, in about a same thermal expansion coefficient as a material of

Guide section (120).