EP2565468A1 - Valve assembly - Google Patents

Abstract

The valve array has reservoir (1) containing a pressurized fluid, a non-return valve (3), and a seat valve (2) that is actuatable so as to allow the fluid to flow out of the reservoir. The seat valve is configured as a pilot control valve connected to the reservoir such that in an open condition of the seat valve a smaller amount of the fluid flows out of the reservoir via the seat valve and a larger amount of the fluid flows out of the reservoir via the non-return valve.

Description

Technical area

The invention relates to a valve arrangement according to the preamble of patent claim 1.

State of the art

Motor vehicles with automatic transmissions are already known from the prior art. These vehicles are increasingly offered with a start / stop function.

Against this background, conventional automatic transmissions comprising a mechanically driven oil pump are equipped with a start / stop function.

In order to enable a faster and more comfortable start-up process, it is necessary to supply switching elements needed for starting in the starting phase of the engine with hydraulic oil.

For this purpose, in particular a hydraulic accumulator can be used, which is filled via a transmission main pump and, if necessary, releases its stored oil volume.

By the publication DE 10 2009 050 847 A1 An apparatus for pulse-like release of a vorratsbaren in a memory amount of fluid has become known.

In this device, a valve assembly is used which consists of an electromagnetic seat valve and a check valve. With this valve arrangement, a leakage-free control of a piston position and a pulse-like release of a vorratsbaren in a memory amount of fluid to be made possible.

A disadvantage here is that a directly controlled seat valve is used.

As soon as high volume flows are required, the seat valve must have correspondingly large flow cross sections. This leads to high switching forces and a large and expensive magnet system.

Particularly when using the valve arrangement in an automatic transmission to realize a start / stop function, high volume flows occur.

The known valve assembly is therefore not very suitable to be used in an automatic transmission for the realization of a start / stop function, since they require a large space and would cause high costs.

Presentation of the invention

The invention is therefore based on the object to provide a valve assembly which can be used in a compact and cost-effective design in an automatic transmission to realize a start / stop function.

The present invention achieves the aforementioned object by the features of patent claim 1.

A valve assembly according to the invention comprises a reservoir containing a pressurized fluid, a poppet valve and a check valve, wherein the poppet valve is operable such that an amount of fluid exits the reservoir.

According to the invention, the poppet valve is designed as a pilot valve and is connected to the accumulator such that when the poppet valve is open, a smaller amount of fluid flows via the poppet valve, which controls that a larger amount of fluid flows out of the accumulator via the check valve.

According to the invention, it has been recognized that such a valve arrangement makes it possible to use a very small and therefore cost-effective electromagnetic seat valve, preferably a microvalve, as a pilot valve since only a small control volume flow, namely the smaller amount of fluid, flows via the seat valve. It has also been recognized that the required control volume flow can be taken from the storage itself. Thus, a self-supply of the seat valve is possible. Advantageously, can be dispensed with a further pressure source. In that regard, a valve assembly is specified, which in a compact and cost-effective design in one Automatic transmission can be used to realize a start / stop function.

Consequently, the object mentioned above is achieved.

The larger amount of fluid could be at least 1.5 times the volume of the smaller amount of fluid. This allows a very compact, small-sized seat valve can be used.

The accumulator could be fluid-conductively connected both to the seat valve and to the check valve. By this specific embodiment, a smaller amount of fluid can be passed through a bypass line to the seat valve, with a larger amount of fluid can be passed through the check valve to a consumer.

From the accumulator, a first conduit could lead to the poppet valve and a second conduit could lead to the check valve, with the smaller amount of fluid passing through the first conduit pushing on a control piston which opens the check valve so that a larger amount of fluid can flow out through the check valve. A control piston can exert pressure by suitable dimensioning on another suitably dimensioned component reliable and trouble-prone.

Against this background, the control piston could abut against a main piston smaller pressurized cross-sectional area. By this specific embodiment, the control piston, as soon as it is pressurized, acts on the main piston with a force such that it is moved. This force can be precisely adjusted based on the area ratios of the areas under pressure.

In the main piston, a needle could be added, which bears against a spring-loaded ball of the check valve. The ball can be moved by means of the needle against the force of a spring. By moving the ball, the check valve is opened, so that the larger amount of fluid can flow to a consumer.

Against this background, the check valve could be connected to or cooperate with a throttle which creates a resistance to the fluid in a flow direction of a fluid and which does not exhibit any resistance to the fluid in the opposite flow direction. The throttle can thus flow-damping effect in a flow direction. The check valve could be located between a throttle and the reservoir.

The throttle could be switched by the seat valve from one direction of flow in the other direction of flow. In this way can be adjusted by the seat valve, whether a fluid quantity is discharged quickly and without much resistance from the memory, or whether it is filled by an external pump with a defined volume flow.

The throttle could independently build or break down a resistance to the fluid, depending on the flow direction of the fluid. This can be dispensed with a connection to the seat valve.

Against this background, the reservoir could be filled with fluid via the throttle. The fluid, preferably a hydraulic oil, can be introduced into the reservoir from an external pump. In the memory, a pressure can be generated thereby.

The valve assembly could include individual parts integrated into the reservoir. As a result, a compact valve assembly is realized. The memory could be designed as a piston accumulator, which has a bottom plate, in which the parts are integrated. The base plate can be easily connected to the piston accumulator after a pre-assembly by a bead flawless. Against this background, it is also conceivable to screw the bottom plate with integrated valve arrangement with the cylindrical, one-sided open housing of the piston accumulator. An advantage of this solution is the high modularity to an existing piston accumulator product range.

The parts could be arranged at an angle of 90 ° to the longitudinal axis of the memory. This arrangement is particularly space-saving.

The memory could have a bottom plate, which is positively connected with this A positive connection can be made inexpensively.

The seat valve could be electromagnetically actuated. Thus, a control by an electrical control unit is possible.

The seat valve designed as a pilot valve could be designed as a 2/2-way seat valve or as a 3/2-way seat valve. A 2/2-way poppet valve is inexpensive. A 3/2-way poppet valve enables a saving of fluid connections, in particular spiral grooves in a control piston.

As a pilot valve is in principle also another type of valve than a seat valve used. In a conceivable embodiment, a slide valve can be used instead of a seat valve.

There are now various possibilities for designing and developing the teaching of the present invention in an advantageous manner. This is on the one hand to the subordinate claims, on the other hand, the following Explanation of preferred embodiments of the valve arrangement according to the invention with reference to the drawing.

In conjunction with the explanation of the preferred embodiments with reference to the drawings, generally preferred embodiments and developments of the teaching are explained.

Brief description of the drawing

Fig. 1

einen schematischen Schaltplan der Ventilanordnung,

Fig. 2

in einer Schnittzeichnung ein erstes Ausführungsbeispiel der Ventilanordnung, wobei zumindest das Rückschlagventil in einer umbördelten Bodenplatte eines Kolbenspeichers integriert ist, und

Fig. 3

in einer Schnittzeichnung ein zweites Ausführungsbeispiel der Ventilanordnung, wobei zumindest das Rückschlagventil in einer Bodenplatte eines Kolbenspeichers integriert ist, welche mit dem Gehäuse des Kolbenspeichers verschraubt ist.

In the drawing show

Fig. 1

a schematic circuit diagram of the valve assembly,

Fig. 2

in a sectional drawing, a first embodiment of the valve assembly, wherein at least the check valve is integrated in a flanged bottom plate of a piston accumulator, and

Fig. 3

in a sectional drawing, a second embodiment of the valve assembly, wherein at least the check valve is integrated in a bottom plate of a piston accumulator, which is bolted to the housing of the piston accumulator.

Embodiment of the invention

Fig. 1 shows a schematic circuit diagram of a valve assembly comprising a memory 1, which contains a pressurized fluid, preferably a hydraulic oil, a seat valve 2 and a check valve 3, wherein the poppet valve 2 is operable such that an amount of fluid from the reservoir 1 exits.

The seat valve 2 is designed as a pilot valve and connected to the memory 1, that when the seat valve 2 is open, a smaller amount of fluid flows through the seat valve 2, which controls that a larger amount of fluid flows through the check valve 3 from the memory 1.

The larger amount of fluid has at least 1.5 times the volume of the smaller amount of fluid. The reservoir 1 is fluid-conductively connected both to the seat valve 2 and to the check valve 3. The check valve 3 is disposed between a throttle 10 and the memory 1.

The check valve 3 is connected to the throttle 10 or cooperates with this. The throttle 10 exhibits a resistance to the fluid in a flow direction of a fluid and exhibits almost no resistance to the fluid in the opposite flow direction.

The throttle 10 is switched by the seat valve 2 from the one flow direction in the other flow direction. However, it is also conceivable for the throttle 10 to independently build or break down a resistance for the fluid as a function of the direction of flow of the fluid.

The memory 1 can be filled via the throttle 10 with fluid. The seat valve 2 is electromagnetically actuated. The valve 2 designed as a pilot valve is designed as a 2/2-way seat valve or as a 3/2-way seat valve.

Fig. 2 shows a first embodiment of a previously described schematically valve arrangement.

From the memory 1, a first line 4 leads to the seat valve 2 and a second line 5 to the check valve 3, wherein the guided through the first line 4 smaller amount of fluid presses on a control piston 6, which opens the check valve 3, so that a larger amount of fluid through the Check valve 3 can drain. The control piston 6 is located on a main piston 7 of smaller pressure-loaded cross-sectional area.

In the main piston 7, a needle 8 is received, which bears against a spring-loaded ball 9 of the check valve 3.

The check valve 3 is integrated in the memory 1. The memory 1 is designed as a piston accumulator, which has a beaded base plate 11, in which the check valve 3 is integrated. The seat valve 2 may also be integrated in the bottom plate 11.

In the memory 1 is added as a fluid hydraulic oil, which can be removed through a throttle 10 in a flow direction to a consumer. This emptying of the memory 1 to the consumer, however, is unthrottled.

Fig. 3 shows a further embodiment of the in Fig. 1 schematically described valve arrangement.

The check valve 3 is integrated in the memory 1. The memory 1 is designed as a piston accumulator, which has a screwed bottom plate 11 ', in which the check valve 3 is integrated. In the bottom plate 11 ', a screw 12 is received, by which the spring action of the ball 9 is adjustable by the spring 13. The seat valve 2 may also be integrated in the bottom plate 11 '.

The piston accumulator according to Fig. 2 and Fig. 3 has a piston 14 which separates a fluid space 15, in which a hydraulic oil is received, from a gas space 16. The housing 17 of the piston accumulator is open on one side, wherein the open side of the bottom plate 11, 11 'is closed.

The operation of the previously described valve arrangements with a feedforward function are described below:

A valve assembly consists of an electromagnetic seat valve 2, a hydraulically releasable check valve 3 and a switchable throttle 10. The pilot-operated check valve 3 is arranged such that it allows a free flow into the memory 1. In the direction of discharge, the check valve 3 acts blocking.

When filling the memory 1, an input volume flow flows through the throttle 10, whereby a throttling action and a controlled filling of the fluid space 15 is achieved. The filling of the memory 1 via the check valve. 3

In order to remove a quantity of fluid from the memory 1, the electromagnetic seat valve 2 is switched to the flow position. The flowing over the seat valve 2 smaller amount of fluid or the prevailing pressure in the memory 1 now acts on an unlocking of the check valve 3, whereby the check valve 3 can be unlocked and flowed through.

At the same time, the throttle 10 is switched in the direction of a free flow through the actuation of the Stitzventils 3 in order to achieve the most lossless emptying of the memory 1.

Fig. 2 shows a particularly advantageous valve arrangement. The memory 1 is designed as a piston accumulator. It is understood that any other type of hydraulic accumulator can be used. The open side of a cylindrical housing 17 is pressure-tightly sealed by a cylindrical bottom plate 11, in which parts of the valve assembly are integrated.

Parts of the valve arrangement, namely the check valve 3, the control piston 6 and the main piston 7, are preferably arranged at an angle of 90 ° to the longitudinal axis of the cylindrical housing 17. The piston 14 is in this case movable along the longitudinal axis. The bottom plate 11 is connected to the housing 17 by a joining process, preferably a positive crimping connection.

The check valve 3 is realized very cost-effectively by a spring-loaded ball 9, namely a roller bearing ball, in a conical valve seat. Via a needle 8 in the main piston 7, which is preferably designed as a needle roller, the ball 9 can be lifted from the valve seat and thus the check valve 3 are unlocked.

In addition, the function of the switchable throttle 10 in the form of radial bores 18 and an annular groove 19 is realized in the main piston 7. In a blocking position of the check valve 3, as shown, the radial bores 18 are partially or completely covered by a wall of the slide bore 20. By a in Fig. 2 not specifically shown partial occlusion of the radial bores 18, a throttle effect is deployed.

The throttle effect is set when filling the memory 1 over the size of an annular surface. The annular surface is determined by the diameter of the slide bore 20 and a taper of the main piston 7 in the region of the radial bores 18.

In a position in which the memory 1 is discharged in the direction of a consumer, due to an axial movement of the main piston 7, a cross-sectional connection to the annular groove 19, namely a control groove, Approved. The connection is determined by the radial bores 18. The annular groove 19 is connectable to a consumer or a pump. The fluid can escape in the aforementioned position in the flow direction to the consumer from the memory 1.

To unload the memory 1, the electromagnetic seat valve 2 is switched to the flow position. The prevailing pressure in the fluid space 15 of the accumulator 1 now acts on the end face 21 of the control piston 6.

The opposite end face and the back of the main piston 7, which rests on the control piston 6, are connected via a further annular groove 23 with an external tank. This creates an axial force of the control piston 6, which acts on the main piston 7 and the needle 8 on the ball 9 of the check valve 3.

Since the pressure-effective surface of the control piston 6 is greater than the resulting by the ball 9 and the valve seat sealing surface, there is a force resultant, which switches the valve assembly in the flow position.

On the circumferential surface of the control piston 6, a spiral groove 22 is provided to establish a connection between a space between the seat valve 2 and the control piston 6 and the further annular groove 23.

The electromagnetic seat valve 2 may also be arranged in the bottom plate 11, 11 'of the memory 1.

With regard to further advantageous embodiments and developments of the teaching of the invention reference is made on the one hand to the general part of the description and on the other hand to the appended claims.

Claims (15)

A valve assembly comprising a reservoir (1) containing a pressurized fluid, a poppet valve (2) and a check valve (3), the poppet valve (2) being operable to exhaust an amount of fluid from the reservoir (1),
characterized in that the poppet valve (2) is configured as a pilot valve and is so connected to the memory (1) that when the poppet valve (2) is open, a smaller amount of fluid flows through the poppet valve (2) which controls a larger amount of fluid the check valve (3) flows out of the reservoir (1). Valve arrangement according to claim 1, characterized in that the memory (1) is fluid-conductively connected both to the seat valve (2) and to the check valve (3). Valve arrangement according to claim 1 or 2, characterized in that from the memory (1) a first line (4) leads to the seat valve (2) and a second line (5) leads to the check valve (3), wherein the first line (4 ) guided smaller amount of fluid on a control piston (6) presses, which opens the check valve (3), so that a larger amount of fluid through the check valve (3) can flow. Valve arrangement according to claim 3, characterized in that the control piston (6) bears against a main piston (7) of smaller pressurized cross-sectional area. Valve arrangement according to claim 4, characterized in that in the main piston (7) a needle (8) is received, which bears against a spring-loaded ball (9) of the check valve (3). Valve arrangement according to one of the preceding claims, characterized in that the check valve (3) is connected to or cooperating with a throttle (10), which in a flow direction of a fluid unfolds a resistance for the fluid and which in the opposite flow direction no resistance to the fluid unfolded. Valve arrangement according to claim 6, characterized in that the throttle (10) through the seat valve (2) from the one flow direction in the other flow direction is switchable. Valve arrangement according to claim 6, characterized in that the throttle (10) independently depending on the flow direction of the fluid up or breaks down a resistance to the fluid. Valve arrangement according to one of claims 6 to 8, characterized in that the memory (1) via the throttle (10) can be filled with fluid. Valve arrangement according to one of the preceding claims, characterized by an integration of individual parts in the memory (1). Valve arrangement according to claim 10, characterized in that the memory (1) is designed as a piston accumulator, which has a bottom plate (11, 11 '), in which the parts are integrated. Valve arrangement according to claim 10 or 11, characterized in that the parts are arranged at an angle of 90 ° to the longitudinal axis of the memory (1). Valve arrangement according to one of the preceding claims, characterized in that the memory (1) has a bottom plate (11) which is positively connected thereto. Valve arrangement according to one of the preceding claims, characterized in that the seat valve (2) is electromagnetically actuated. Valve arrangement according to one of the preceding claims, characterized in that the pilot valve designed as a seat valve (2) is designed as a 2/2-way seat valve or as a 3/2-way seat valve.

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