DE10302780B4 - Valve element for a control valve of a brake booster, brake booster and method for producing a valve element - Google Patents

Abstract

Valve element (38, 138) for a control valve (14) of a brake booster (10) with
A valve disk (40, 140) having a valve seat surface (46, 146),
A retaining ring (54, 154) and
A flexible bellows (48, 148) interconnecting the valve disk (40; 140) and the retaining ring (54; 154),
wherein the retaining ring (54; 154) of a dimensionally stable material and the valve disk (40; 140) and the bellows (48; 148) are formed at least in regions from a flexible plastic material,
wherein a biasing member (58; 158) is provided between the valve disc (40; 140) and the retaining ring (54; 154) which biases the valve disc (40; 140) away from the retaining ring (54; 154) and the valve member (38, 138) is designed as a preassembled module,
characterized in that the flexible plastic material is adhesively attached to the dimensionally stable material and that the retaining ring (54; 154) has an axial circumferential groove (56; 156) for receiving one end of the biasing member (58;

Description

The The present invention relates to a valve element for a control valve a brake booster with the features of the preamble of claim 1.

such Valve elements are already used in vacuum brake boosters for vehicle brake systems used according to the prior art. A brake booster this Art's job is to brake one of a driver by a brake pedal amplify the vehicle applied pedal actuation force and the reinforced one operating force to a brake system for controlling the brakes and for generating to transmit a corresponding braking force. For this purpose, the Brake booster one Low pressure chamber and one of this by a movable wall fluid-tight separate working chamber, wherein by means of the control valve depending on its operating position in the working chamber, an overpressure across from the vacuum chamber can be constructed. This overpressure in the working chamber leads to a displacement of the movable wall, which force-transmitting with a control valve housing is coupled, so the over a force input member from the brake pedal initiated Pedalbetätigungskraft reinforced can be. By means of the displaced movable wall opposite the Brake actuation force increased Braking force is then over transmit a force output element to the brake system.

such Brake booster are relatively expensive built and therefore require a lot of time during assembly. In particular, the control valve, which is decisive for the behavior of the brake booster, is at conventional Brake boosters made of a plurality of individual components relatively expensive.

For example, show the EP 0 327 997 A2 or the DE 28 45 794 A1 relatively elaborately designed control valves in which the valve element is constructed in several parts and must be assembled in a time-consuming manner during assembly of the brake booster. Also, for the maintenance of such a brake booster, it has hitherto been necessary to provide a large number of individual parts in order to be able to replace them if necessary in the event of wear or failure. This requires a relatively high logistical effort.

From the generic state of the art according to the DE 197 56 225 A1 is a valve element with the features according to the preamble of claim 1 be known. This valve element is also provided with a biasing element which biases the valve disk at a distance from the retaining ring in an initial position. The dimensionally stable parts are held by positive engagement in the flexible parts. The position of the biasing member is roughly dictated by the shape of the flexible bellows. However, in the course of operation, the biasing member can move in an undesirable manner, which can lead to an impairment of the function of the bellows or its destruction.

From the EP 1 216 906 A2 a valve element is known in which a dimensionally stable part is poured into the valve disk. At the end remote from the tray of the flexible bellows is clamped via a clamping arrangement with other components of the control valve. A design of the valve element as a pre-assembled assembly, in particular with a biasing element housed therein, is not known from this prior art.

The same applies to from the DE 195 45 947 A1 known arrangement and the valve element provided therein.

Finally, the shows DE 33 27 534 C2 a method for producing a component in which a dimensionally stable part is embedded.

It An object of the present invention is a valve element for a control valve a brake booster to provide, with which the construction of the control valve considerably is simplified and thus both the assembly and the maintenance facilitated with such a valve element brake booster and reliable in operation works.

These Task is achieved by a valve element for a control valve of a brake booster with the Characteristics of claim 1 solved.

The design of the valve element as a unitary preassembled module, it is possible to use this in the preassembled state in the assembly of the brake booster as a single component, without a variety of different components are needed to assemble the control valve. This can be achieved in particular in that the various components of the valve element, which consist on the one hand of dimensionally stable material and on the other hand of flexible plastic material, are adhesively joined together. In other words, in the manufacture of the valve element, its components are joined inseparably, so that the valve element can be handled as a non-separable single component in the sequence. During assembly, this single component can be used as a whole simply in the overall arrangement of the brake booster for the realization of the control valve. During maintenance this can be considered Individual component trained valve element can be replaced only as a whole, so that the logistical effort that would be required to provide all the individual components of the valve element can be significantly reduced.

The adhesive Connection of the various components made of dimensionally stable material and flexible plastic material can be achieved, for example be that flexible plastic material to the dimensionally stable Material is injected. So it is possible, the valve element through an injection molding process in which the components of dimensionally stable material be overmoulded with flexible plastic material. Equally is it is possible the components of dimensionally stable material with separately manufactured Bond components made of flexible plastic material.

at a development of the invention is provided that the valve disc is formed with a reinforcement of dimensionally stable material. By This measure can the the valve seat surface having valve disc in its for the function of the control valve relevant area, namely the area of the valve seat surface, be stabilized by the reinforcement. This can cause unwanted deformations the valve disc prevents any leaks in the area the valve seat surface would result. A simple production engineering realization of the reinforcement of the Valve plates can be achieved by the reinforcement a annular reinforcing washer having. Such an annular reinforcing washer is inexpensive available and increased the stiffness against an unwanted Deformation.

Regarding Manufacturing in the context of an injection molding process can in a further development be provided the invention that the reinforcing disc with retaining recesses is trained. Holding pins can then engage in these retaining recesses, which the reinforcing disk while the injection molding process hold in a desired position within the injection mold.

in the Operation, the control valve must be in the area of the valve seat possibility a fluid-tight system with a corresponding sealing seat make sure, taking possible Unevenness must be compensated at the sealing seat. It is therefore desirable the valve seat surface to train flexibly. Therefore, it is provided in a development of the invention, that for the formation of the valve seat at least on one side the reinforcement disc flexible plastic material is sprayed on. The in itself dimensionally stable reinforcing washer can such irregularities at the sealing seat do not even compensate. By spraying flexible, in particular rubber-elastic, plastic material the reinforcement disc can these inequalities be compensated by deformation of the plastic material, so that for a fluid-tight contact of the sealing seat is ensured at the valve seat surface.

in the Operation of the brake booster the valve element is deformed depending on the operating state. It is Therefore, it is necessary to form the valve element such that it under its release, i. in a state in which no Operating forces the brake booster be exercised moved back to its original position. Around this fast and reliable guarantee to be able to is according to the invention provided that between the valve plate and the retaining ring a Biasing element is provided, which the valve disc in a tensioned predetermined distance to the retaining ring. The biasing element is to be interpreted as meaning the function of the control valve and so that the brake booster not impaired. This means that the biasing element against deformation of the Valve element may not apply excessive counter forces. Yet the preloading element is to be dimensioned so that it releases after release of the Brake booster, i.e. after reducing the brake actuation force to the amount Zero, reliable the valve element is returned to its original shape.

at However, using a biasing element should be considered that this itself to an undesirable deformation of the valve element to lead can. To prevent this is in a development of the invention provided that on the valve seat surface side facing away from the reinforcing disk an end of the biasing element is applied. This can be achieved that the reinforcing disk made of dimensionally stable material on the one hand - how set out above - for stabilization the valve seat surface against unwanted Deformations and resulting leaks used On the other hand, however, also for the initiation of the biasing force exerted by the biasing member. In In this context, the invention provides that the retaining ring an axial circumferential groove for receiving the other end of the biasing member having. Thus, the biasing element between the two components made of dimensionally stable material, namely the reinforcing washer on the one hand and the retaining ring on the other hand, be arranged and its prestressing forces each into the component of dimensionally stable material. Thereby become the more sensitive to wear Components of the valve element made of flexible plastic material spared and the life of the valve element increased overall.

The control valve can be used for optional Ver Bonding and separation of the working chamber and vacuum chamber be configured differently. It is advisable to form the valve seats required for this purpose directly on the valve element in order to keep the number of moving and actuated parts of the control valve small. Therefore, it is provided in a development of the invention that the valve seat surface has two valve seats. Thus, it is possible to cooperate with the first valve seat with a control valve housing and the second valve seat with an actuating piston. This allows all necessary for the function of the control valve interactions of valve seats and sealing seats on the valve element can be realized.

Around the valve element fluid-tight in the control valve housing lead to can, is it possible according to the invention Provide radial sealant. Also in the field of radial sealants should be unwanted Deformations are prevented. Therefore, in a variant of the invention provided that formed on the retaining ring a radial circumferential groove is at which radial sealant made of flexible plastic material are attachable. The retaining ring made of dimensionally stable material stabilized Thus, in turn, the radial sealant, so that undesirable deformations and resulting leaks can be avoided. According to the invention, these Radial sealant in turn molded or glued to the peripheral ring be. This can be done in a separate manufacturing step. Prefers However, these radial sealants - in the invention variant one by injection molding manufactured valve element - already produced during spraying of the valve element.

to further stabilization of the retaining ring having area the valve element may be provided according to the invention that the Valve element in the region of the retaining ring with a support ring dimensionally stable material is. This support ring can be formed directly on the retaining ring, for example via connecting webs, or as a separate component over the flexible plastic material to be connected to the retaining ring. The support ring may serve to guide the valve element exactly in the control valve housing. Further can the support ring further reduce the tendency of the valve element to deform. This has a particularly advantageous effect on the sealing properties of Radial sealant off.

above was repeatedly referred to the different materials the components of the valve element according to the invention. Basically be used as a dimensionally stable material any material which due to its dimensional stability and its wear properties for one Use within a brake booster is suitable. For cost reasons are offered In addition to dimensionally stable plastic materials and metallic materials on, in particular steel. Furthermore, they offer themselves as flexible plastic material rubber-elastic materials, in particular rubber or the like.

These Material combination offers a good mutual compatibility, a high wear resistance, a good corrosion resistance, but also a cost effective Availability.

The The invention further relates to a brake booster with a force input element for introducing a brake operating force, a force output member for deriving a relation to the brake operating force increased Braking force to a brake system, a vacuum chamber and a from the vacuum chamber by a movable wall fluid-tight separated Working chamber, a control valve with a control valve housing and a relative to this axially movable valve element, in particular the This type of brake booster is according to the invention provided that the valve element having a valve seat surface having Valve plate, a retaining ring and a valve plate and the Holding ring interconnecting flexible bellows is executed, wherein the retaining ring of a dimensionally stable material and the valve disc and the bellows at least partially made of a flexible plastic material are formed. Furthermore, in this brake booster according to the invention is the Control valve housing for force-transmitting coupling executed with the movable wall. The valve element is for power-transmitting Coupling performed with the force input element. In operation of this brake booster is to obtain a braking force determining pressure difference between Working chamber and vacuum chamber by moving the valve element relative to the control valve housing at least atmospheric pressure can be fed to the working chamber.

As already mentioned, such brake booster known from the prior art and because of their relatively complicated structure in terms of their parts production, installation and maintenance very expensive and time-consuming. To simplify such a brake booster, the invention therefore provides that the valve element is designed as a preassembled module, wherein the flexible plastic material is adhesively attached to the dimensionally stable material. Thus, the valve element and thus a substantial part of the control valve can already be preassembled into a unit, which unit can then be used in the assembly of the brake booster as a whole in this and, if necessary, out as a whole in its maintenance can be exchanged. This facilitates the installation and maintenance of the brake booster according to the invention over the prior art considerably. In addition, the number of parts of the brake booster is reduced, which simplifies the required logistics.

In a development is provided that the valve element on the Valve seat has two valve seats, wherein one of the valve seats with a corresponding Sealing seat on the control valve housing and the other of the valve seats with a corresponding sealing seat on an actuating piston of the control valve cooperate. This interaction can according to the invention in such a way done that in a ready position of the control valve both valve seats each at its corresponding sealing seat abut that in a deviating from the standby position first operating position of the control valve only one of the two Valves seats fluid-tight against the corresponding sealing seat and the other separated from its corresponding sealing seat is and that in one of the readiness position and the first Operating position deviating second operating position of the control valve the other valve seat, fluid-tight at its corresponding valve seat abuts and a valve seat from its corresponding valve seat is disconnected.

This leads to, that in the standby position vacuum chamber, working chamber and atmosphere are separated by the valve element, that in the first Operating position working chamber and atmosphere to achieve the braking force determining pressure difference between the working chamber and the vacuum chamber are connected to each other and that in the second operating position the working chamber with the vacuum chamber for reducing the pressure difference connected to each other.

With In other words, is in the ready position of the control valve the valve element to the sealing seat of the control valve housing and the sealing seat of the actuating piston lies at its corresponding valve seat of the valve element at. When pressed the brake pedal becomes the actuating piston with its sealing seat from the corresponding valve seat of the valve element lifted, leaving the working chamber connected to the atmosphere becomes. This results in the working chamber opposite the Negative pressure chamber an overpressure, which results in a displacement of the control valve housing via the movable wall leads and thus to a reinforcement the brake actuation force. After all In this first operating position an equilibrium state arises a, so that the valve element together with the control valve housing again on the actuating piston too moved. After release of the brake pedal, those initiated by the brake system reset personnel to that the actuating piston and move the force input member back to its original position and take the valve element with you. This will be the first valve seat lifted from the sealing seat on the control valve housing, so that the Working chamber is connected to the vacuum chamber and thereby the Pressure difference between the vacuum chamber and the working chamber largely degraded. After all the control valve returns to its standby position.

The The invention further relates to a method for producing a valve element for a Control valve of a brake booster, in particular a valve element of the type described above and in particular for a Brake booster of the type described above.

As already explained at the beginning are conventional Valve elements constructed of several components and during the Assembly of the brake booster relatively time-consuming reassemble. The method according to the invention is intended to be a possibility be created, with which the valve element prefabricated as a unit can be and then as a whole during the assembly of the control valve or the brake booster as Whole can be further processed.

• A) Fixieren eines Halterings aus formstabilem Material in einer Spritzgießform,
• B) Einspritzen von flexiblem Kunststoffmaterial in die Spritzgießform,
• C) Aushärten des eingespritzten flexiblen Kunststoffmaterials und
• D) Ausformen des Ventilelements.

The method according to the invention provides for the following steps:

• A) fixing a retaining ring of dimensionally stable material in an injection mold,
• B) injecting flexible plastic material into the injection mold,
• C) curing the injected flexible plastic material and
• D) shaping the valve element.

The Components of the valve element made of dimensionally stable material and flexible Plastic material is thus connected to each other by injection molding, by first the components of dimensionally stable material in the injection mold be inserted and then be overmoulded with the flexible plastic material. It lays down the flexible plastic material in the injection mold to the Components made of dimensionally stable material and adheres to these adhesively after curing at. After forming the valve element, this can then be considered uniform Assembly in the brake booster to be built in.

In a further development of the method according to the invention, it is provided that in step A), in addition to the retaining ring, a reinforcing disk is fixed in the injection mold. The reinforcing disk can for example be used to who to amplify a certain area of the valve element, for example the valve plate area, which is particularly mechanically stressed during operation. To fix the reinforcing disk in the injection mold can be provided in a development of the inventions to the invention process that the reinforcing disk has retaining recesses into which retaining pins engage for fixing in the injection mold. It should be noted that the retaining recesses of the reinforcing disk are to be mounted at a position where they do not interfere with the valve seats formed on the valve seat surface. For example, it is possible to arrange the retaining recesses in a valve element with two valve seats on the valve seat surface between the two valve seats.

to further stabilization of the valve element can - as already explained above - in the area of the retaining ring a support ring be provided. Therefor can by the method according to the invention be provided that the support ring additionally is fixed to the retaining ring in the injection mold. The support ring can to the leadership serve the valve element in a control valve housing. In this case must the support ring such in the injection mold be fixed that no plastic material reaches its outer peripheral surface and settles there, so that the outer peripheral surface of the Leadership of Valve element can be used.

As already stated, in a preferred embodiment of the valve element according to the invention a biasing means may be provided, which the valve element in biasing a certain starting position. Also this biasing agent, For example, a coil spring is already in the production attached to the valve element to a costly retrofitting to avoid. It should be noted, however, that the biasing means in impaired its function would be when during the injection molding process flexible plastic material precipitates on the biasing means. Therefore It is necessary, the biasing means during the injection of the plastic material in the injection mold to encapsulate. The inventive method in this case, in step A), in addition to the retaining ring Biasing means in the injection mold and inserted into a biasing agent cavity prior to performing Step B) is encapsulated. This can be done, for example, by that the biasing means in the Vorspannmittelkavität on a Pretensioner holder is held and covered.

Of the Biasing means holder forms during the Steps B) and C) forms part of the injection mold and is after step C) again, so that the biasing agent escape from the cavity can. For example, the biasing means is in a compressed state in the cavity kept and relaxed - so far possible - at removal of the biasing agent holder. It can then, for example, between Move the valve plate and the retaining ring in its desired position. The biasing agent cavity is preferably formed in the retaining ring as Axialumfangsnut.

The Invention will be described below with reference to the accompanying schematic Figures exemplified. It shows:

1 an axis-containing cross section of a brake booster according to the invention;

2 an exploded view of a first embodiment of a valve element according to the invention;

3 a view accordingly 2 a second embodiment of a valve element according to the invention;

4 a perspective view of the valve element according to 3 ;

5 a schematic representation of the injection mold during the process according to the invention prior to their closing and

6 a partial perspective sectional view of the injection mold according to the invention in the closed state immediately prior to injection of the plastic material.

In 1 is an inventive brake booster shown in achsenthaltender sectional view and generally with 10 designated. This includes a brake booster housing 12 which is displaceable on a control valve housing 16 a control valve 14 is appropriate. The brake booster housing 12 encapsulates a working chamber 18 and a vacuum chamber 20 that has one with the control valve body 16 coupled to the joint movement wall 22 are separated from each other.

In the control valve housing 16 sticks out of the in 1 right side of a force input element 24 on which a brake operating force F ₁ can be applied via a brake pedal (not shown ₎ . The force input element 24 is in a push rod 26 taken, which in turn at their from the force input element 24 distal end is spherically formed and with this end in an actuating piston 28 is included. The actuating piston 28 is also ver pushed in the axial direction and acts on his from the push rod 26 distant end with a graduated sensing piston 30 together. The sensing piston 30 is in Direction of the longitudinal axis A slidably in the control valve housing 16 guided and arrives at a shift in 1 to the left in contact with a rubber-elastic reaction disc 32 , which in turn in a force output element 34 is received and this ultimately in response to a shift of the force input element 24 along the axis A in 1 to the left from the control valve housing 16 pushes out. In addition to the sensing piston 30 lies on the reaction disk 32 also for power transmission an annular end face 36 of the control valve housing 16 at.

As already mentioned above, the brake booster comprises 10 a control valve 14 , Next to the control valve housing 16 this is a valve element 38 assigned. The valve element 38 is in 2 shown enlarged as a single part in section. It includes a valve plate 40 , which is a range of flexible plastic material 42 and an embedded in this area of dimensionally stable material 44 has, for example, steel. The area 44 is formed by an annular disk. At the side facing away from the annular disc side of the valve disk 40 is a valve seat surface 46 trained, whose function will be discussed in more detail below. The valve plate 40 is over a bellows 48 made of flexible plastic material with a guide area 50 connected. The management area 50 includes a region of flexible plastic material 52 , which is adhesive with a retaining ring 54 connected is. The retaining ring 54 has an axial circumferential groove 56 on, ie a groove which extends in the axial direction to the valve plate 40 opens. In the axial circumferential groove 56 is a spring element 58 taken, which at his of the retaining ring 54 distant end on the reinforcing disc 44 is applied. The spring element 58 is dimensioned such that it is the valve element 38 in his in 2 pretensioned form. The retaining ring 54 also has an outer circumferential groove 60 in which a lip seal 62 made of rubber-elastic plastic material is introduced. The valve element 38 is with a cavity 64 formed, through which the push rod 26 passed through.

As 1 it can be seen, the valve element 38 with its retaining ring 54 via a compression spring 66 in contact with a stop flange 68 held the control valve housing. This is the lip seal 62 fluid-tight on the inner peripheral surface of the stop flange 68 at. In the in 1 shown ready position of the control valve 14 is a tight fit 70 of the control valve housing 16 at a corresponding valve seat 72 the valve seat surface 46 at. Furthermore, there is a sealing seat 74 of the actuating piston 28 at a corresponding valve seat 76 the valve seat surface 46 at.

Upon actuation of the brake pedal, not shown, the brake booster behaves 10 as follows. The force input element 21 is applied to the brake actuation force F ₁ in the direction of the axis A. This will be the force input element 24 in 1 moved to the left and pushes the push rod 26 also to the left. This will cause the actuating piston 28 with his seal seat 74 from the valve seat 76 lifted. By this movement of the actuating piston 28 relative to the valve disk becomes the working chamber 18 connected to the ambient atmosphere, so that in the working chamber 18 builds up a pressure according to the ambient pressure. It raises a pressure difference on the movable wall 22 one, because in the vacuum chamber 20 relative to the now increased to atmospheric pressure in the working chamber 18 a negative pressure prevails. This pressure difference leads to a displacement of the movable wall 22 , this being the control valve housing 16 entraining. During this movement of the control valve housing 16 remains the valve seat 72 in contact with the sealing seat 70 ie the valve element 38 shifts under the action of the compression spring 66 with the control valve housing 16 in 1 to the left with.

Overall, the power output element is on 34 a relation to the brake actuation force F ₁ increased braking force F ₂ transmitted, which from the on the actuating piston 28 , the sensing piston 30 as well as the reaction disc 32 on the force output element 34 transmitted force component as well as due to the movement of the movable wall 22 due to the pressure difference between the working chamber 18 and the vacuum chamber 20 caused over the frontal area 36 of the control valve housing 16 on the reaction disk 32 and finally to the power output member 34 composed transmitted force component. The applied by a driver via the brake pedal to the force input member brake actuation force F ₁ is thus by the brake booster 10 reinforced accordingly.

Upon release of the force input element 24 ie, when the amount of the brake operating force F _{1 is} reduced to zero, the power input member moves 24 in 1 to the right back to its original position, taking the push rod 26 and the actuating piston 28 With. This first puts the actuating piston 28 with his seal seat 74 to the valve seat 76 the valve seat surface 46 at. In a further return movement of the actuating piston 28 becomes the valve plate 40 in the direction of the axis A in 1 taken to the right, so that the valve seat 72 from the sealing seat 70 of the control valve housing 60 takes off. This results in a connection of the working chamber 18 with the vacuum chamber 20 , wherein by the application of the actuating piston 28 at his tight seat 74 at the valve seat 76 the valve seat surface 46 the connection between the working chamber of the ambient atmosphere is interrupted again. By the connection of the working chamber 18 and vacuum chamber 20 over the valve seat 72 lifted sealing seat 70 it comes to a reduction of the pressure difference on the movable wall 22 , where the control valve housing 16 in his in 1 shown ready position moves back until it finally returns to the in 1 shown supply, in which both the sealing seat 70 as well as the seal seat 74 at its corresponding valve seat 72 and 76 issue. In this ready position there is almost equal pressure equality between the working chamber 18 and the vacuum chamber 20 ,

1 shows that the brake booster according to the invention is relatively complex composed of many components. However, the valve element 38 , as in 2 shown enlarged in detail, as a prefabricated module uniform design and used as a whole in the assembly in the control valve housing. On the production of the valve element 38 will be referred to below with reference to 5 and 6 still in detail received. It should be noted at this point only that the formation of the valve element 38 as a prefabricated assembly, the assembly of the brake booster 10 considerably simplified.

3 shows a relative to the valve element 38 out 2 slightly modified valve element, the same reference numerals as in its description for the same or equivalent components 2 be used, but preceded by the number "1".

The valve element 138 according to 3 and 4 differs from the valve element 38 according to 2 mainly in management 150 , The retaining ring 154 is substantially U-shaped profile and in turn has an Axialumfangsnut 156 for receiving the spring element 158 on. In addition to the retaining ring 154 is in the leadership area 150 a support ring 178 provided, which for guiding the valve element 138 in the control valve housing 16 serves. The support ring 178 and the retaining ring 154 are over several circumferentially consecutive connection areas 179 connected with each other. The connection areas 179 are via slot recesses 180 separated in the circumferential direction, wherein the slot recesses 180 filled with flexible plastic material. The flexible plastic material extends from the valve plate 140 and the material area 152 over the bellows 148 in the material area 152 radially inside the retaining ring 153 , From this material area 152 Starting from the flexible plastic material extends through the slot recesses 180 around the retaining ring 154 around on its outer peripheral surface in its outer peripheral region 160 where it's the lip seal 162 formed. The entire the cavity 164 surrounding inner peripheral surface of the valve element 138 is therefore formed with flexible plastic material. The reinforcement disc 144 is, as already with respect to the reinforcing disk 44 described embedded in the flexible plastic material and from this to the valve seat surface 146 facing side and at the back at least partially covered with flexible plastic material which adheres adhesively to the reinforcing disk. Also the valve element 138 according to 3 has the advantage that it can be used as an integrally formed module easily in the control valve housing of a brake booster and thus consuming and time-consuming assembly steps for providing the valve element in the control valve housing during assembly or maintenance of the brake booster can be avoided.

5 and 6 show schematic views, which for explaining the manufacture of the valve element 38 according to 2 serve.

In 5 is a multi-part injection mold for the production of the valve element 38 according to 2 shown in schematic and partially sectioned illustration. The injection mold comprises a first molded part 82 , to which a plurality of retaining pins 84 are attached. The retaining pins 84 serve to the reinforcing disc 44 having corresponding retaining recesses, not shown, in position to hold in the mold. To the first molding 82 closes one of this detachable second molding 86 at which in 5 is shown in section and which one of the outer contour of the valve element 38 in the negative corresponding cavity 88 having. From the second molding 86 is removed in 5 a third molding 90 shown, in which the retaining ring 54 is used. This extends with his in 5 right end in a fourth molding 92 , In the third molding 90 and the fourth molding 92 are corresponding ring openings provided for receiving the retaining ring 54 , The third molding 90 and the fourth molding 92 are detachable from each other.

Special attention is on the spring element 58 to judge which in 5 is shown in its relaxed state. This is according to arrow P in the intended for this Axialumfangsnut 56 in the retaining ring 54 pressed in and over a penholder 96 encapsulated in this. It should be noted that the penholder 96 in 5 again only in section and only partially shown. In fact, this is designed in several parts, with the individual parts in 5 in the radial direction can be moved so that they feather 58 in the corresponding Axialumfangsnut 56 hold and encapsulate in it.

After the spring according to arrow P using the spring holder 96 in the Axialumfangsnut 56 pressed in and encapsulated in this, are the moldings 82 and 86 as well as the moldings 90 and 92 put together so that the core 94 in the cavity 88 penetrates and thus creates a gap between the cavity inner surface and the core outer surface.

After joining the individual moldings, one arrives at a state indicated by a perspective view according to FIG 6 partially broken up. One recognizes that the reinforcement disk 44 with their retaining recesses on the at the first molding 82 trained retaining pin 84 is attached and held in the form. The core 94 penetrates the inner opening of the reinforcing disk 44 , Further defines the inner contour of the cavity 88 as well as the outer contour of the core 94 a cavity that matches the course of the bellows 48 equivalent. The penholder parts 96 close the Axialumfangsnut 56 of the retaining ring 54 , in which Axialumfangsnut 56 the spring element 58 is pressed in. This means that the spring element 58 in the axial circumferential groove 56 by means of the spring holder parts 96 is encapsulated. The outer circumferential groove 62 is via channels, not shown, with the cavity 88 connected.

In the corresponding 6 now shown shape, for example via inflow channels 98 as well as other channels not shown injected plastic injection molding material, which then fills the cavities defined in the form. This will be the reinforcing disc 44 for forming the valve seat surface and the corresponding region of flexible plastic material 42 as well as molded on its back with flexible plastic material. Furthermore, in this injection process, the flexible bellows is formed in the region of the cavity 88 out. In addition, the retaining ring 54 sprayed accordingly and it forms the lip seal 62 out.

After sufficient cross-linking of the flexible elastic material, that is to say after its "hardening", the spray blank is formed, whereby the individual molded parts are formed 82 . 86 . 96 and 90 moved apart. It should be noted that it is also in the molding 86 is a multi-part molded part, which can be moved apart in the radial direction. Finally, the penholder parts 96 away. When removing the spring holder parts 96 occurs the spring 58 under their spring action from the Axialumfangsnut 56 and lies down on the opposite surface of the reinforcing disk 44 like this in 2 is shown. One thus obtains the valve element 38 according to 2 , wherein the individual components of dimensionally stable material, such as the reinforcing disk 44 and the retaining ring 50 , are partially enclosed by the rubber-elastic flexible plastic material which adhesively adheres to the latter due to the Anspritzvorgangs. In addition, the sealing lip 62 on the retaining ring 54 molded. The spring element 58 remains without contact with the plastic material, since it is in the Axialumfangsnut during the injection process 56 was encapsulated.

The invention shows a valve element, a brake booster formed with a corresponding valve element and a method for producing the valve element according to the invention. The main advantage of the invention is that the valve element is designed as an integrally preassembled module, which can be used as a whole in the brake booster during its assembly or handled during its maintenance, without having to be handled a variety zusammenzufügender individual components for the valve element. Regarding 5 and 6 was an injection molding process for the production of the valve element according to the invention after 2 explained. It is understood that this represents only one possibility for producing a valve element according to the invention. Similarly, it is also possible to produce the individual components of flexible plastic material and dimensionally stable material separately and then put together by gluing into a unit.

Claims (23)

Valve element ( 38 ; 138 ) for a control valve ( 14 ) of a brake booster ( 10 ) with - a valve seat surface ( 46 ; 146 ) having valve plate ( 40 ; 140 ), - a retaining ring ( 54 ; 154 ) and - one the valve disc ( 40 ; 140 ) and the retaining ring ( 54 ; 154 ) interconnecting flexible bellows ( 48 ; 148 ), wherein the retaining ring ( 54 ; 154 ) made of a dimensionally stable material and the valve disc ( 40 ; 140 ) as well as the bellows ( 48 ; 148 ) are at least partially formed of a flexible plastic material, wherein between the valve disc ( 40 ; 140 ) and the retaining ring ( 54 ; 154 ) a biasing element ( 58 ; 158 ) is provided, which the valve disc ( 40 ; 140 ) at a distance from the retaining ring ( 54 ; 154 ) and wherein the valve element ( 38 ; 138 ) is formed as a preassembled module, characterized in that the flexible plastic material is adhesively attached to the dimensionally stable material and that the retaining ring ( 54 ; 154 ) an axial circumferential groove ( 56 ; 156 ) for receiving one end of the biasing element ( 58 ; 158 ) having. Valve element ( 38 ; 138 ) according to claim 1, characterized in that the flexible plastic material is molded onto the dimensionally stable material. Valve element according to claim 1, characterized in that that the flexible plastic material with the dimensionally stable material is glued. Valve element ( 38 ; 138 ) according to one of the preceding claims, characterized in that the valve disc ( 40 ; 140 ) with a reinforcement ( 44 ; 144 ) is made of dimensionally stable material. Valve element ( 38 ; 138 ) according to claim 4, characterized in that the reinforcement comprises an annular reinforcing disk ( 44 ; 144 ) having. Valve element ( 38 ; 138 ) according to claim 5, characterized in that the reinforcing disk ( 44 ; 144 ) is formed with retaining recesses. Valve element ( 38 ; 138 ) according to claim 5 or 6, characterized in that for the formation of the valve seat surface ( 46 ; 146 ) at least on one side of the reinforcing disk ( 44 ; 144 ) flexible plastic material ( 42 ; 142 ) is sprayed on. Valve element ( 38 ; 138 ) according to claim 7, characterized in that on the valve seat surface ( 46 ; 146 ) facing away from the reinforcing disk ( 44 ; 144 ) one end of the biasing element ( 58 ; 158 ) is present. Valve element ( 38 ; 138 ) according to one of the preceding claims, characterized in that the valve seat surface ( 46 ; 146 ) two valve seats ( 72 . 76 ) having. Valve element ( 38 ; 138 ) according to one of the preceding claims, characterized in that on the retaining ring ( 54 ; 154 ) a Radial Umfangsseinstich ( 60 ; 160 ) is formed on which radial sealant ( 62 ; 162 ) are made of flexible plastic material attachable. Valve element ( 38 ; 138 ) according to claim 10, characterized in that the radial sealing means ( 62 ; 162 ) to the retaining ring ( 54 ; 154 ) are sprayed. Valve element ( 138 ) according to one of the preceding claims, characterized in that in the region of the retaining ring ( 154 ) a support ring ( 178 ) of dimensionally stable material. Valve element ( 38 ; 138 ) according to one of the preceding claims, characterized in that the dimensionally stable material is a metallic material, in particular steel. Valve element ( 38 ; 138 ) according to one of the preceding claims, characterized in that the flexible plastic material is a rubber-elastic material. Brake booster ( 10 ), comprising: - a force input element ( 24 ) for introducing a brake actuation force (F ₁ ), - a force output member ( 34 ) For deriving a relative to the brake operating force (F ₁₎ increased braking force (F ₂₎ to a brake system, - (a vacuum chamber 20 ) as well as one of the vacuum chamber ( 20 ) by a movable wall ( 22 ) fluid-tight separate working chamber ( 18 ), - a control valve ( 14 ) with a control valve housing ( 16 ) and a relative to this axially movable valve element ( 38 ; 138 ) according to one of the preceding claims, wherein the valve element ( 38 ) with a valve seat surface ( 46 ) having valve plate ( 40 ), a retaining ring ( 54 ) and a valve disc ( 40 ) and the retaining ring ( 54 ) interconnecting flexible bellows ( 48 ) is executed, wherein the retaining ring ( 54 ) made of a dimensionally stable material and the valve disc ( 40 ) as well as the bellows ( 48 ) are at least partially formed of a flexible plastic material, wherein further the control valve housing ( 16 ) for force-transmitting coupling with the movable wall ( 22 ) is executed, further wherein the valve element ( 38 ) for force-transmitting coupling with the force input element ( 24 ) and wherein to achieve a braking force (F ₂ ) determining the pressure difference between the working chamber ( 18 ) and vacuum chamber ( 20 ) by moving the valve element ( 38 ) relative to the control valve housing ( 16 ) At least atmospheric pressure to the working chamber ( 18 ) can be fed. Brake booster ( 10 ) according to claim 15, characterized in that the valve element ( 38 ) on the valve seat surface ( 46 ) two valve seats ( 72 . 76 ), wherein one of the valve seats ( 72 ) with a corresponding sealing seat ( 70 ) on the control valve housing ( 16 ) and the other of the valve seats ( 76 ) with a corresponding sealing seat ( 74 ) on an actuating piston ( 28 ) of the control valve ( 14 ) interact. Brake booster ( 10 ) according to claim 16, characterized in that in a ready position of the control valve ( 14 ) both valve seats ( 72 . 76 ) at their corresponding sealing seats ( 70 . 74 ) abut that in a deviating from the standby position first operating position of the control valve ( 14 ) only one of the two valve seats ( 72 ) at the corresponding sealing seat ( 70 ) is fluid-tight and the other ( 76 ) from its corresponding sealing seat ( 74 ) Is separated and that in a deviating from the standby position and the first operating position second Betriebsstel the control valve ( 14 ) the other valve seat ( 76 ) at its corresponding sealing seat ( 74 ) is fluid-tight and the one valve seat ( 72 ) from its corresponding sealing seat ( 70 ) is disconnected. Brake booster ( 10 ) according to claim 17, characterized in that in the ready position vacuum chamber ( 20 ), Working chamber ( 18 ) and atmosphere through the control valve ( 14 ) are separated from each other, that in the first Betriebsbsstellung working chamber ( 18 ) and atmosphere for obtaining the braking force (F ₂ ) determining pressure difference between the working chamber ( 18 ) and the vacuum chamber ( 20 ) are connected to each other and that in the second operating position, the working chamber ( 18 ) with the vacuum chamber ( 20 ) are connected to each other to reduce the pressure difference. Method for producing a valve element ( 38 ; 138 ) for a control valve ( 14 ) of a brake booster ( 10 ), in particular according to one of claims 1 to 14, characterized by the steps: A) fixing a retaining ring ( 54 ; 154 ) of dimensionally stable material in an injection mold ( 90 ), Inserting a biasing means ( 58 ) in a bias cavity ( 56 ; 156 ) of the injection mold ( 82 . 86 . 90 . 92 . 96 ) and capsules of the biasing agent ( 58 ) in the biasing agent cavity ( 56 ; 156 ) via a biasing agent holder ( 96 ). B) injection of flexible plastic material into the injection mold ( 82 . 86 . 90 . 92 . 96 C) curing the injected flexible plastic material and D) molding the valve element (FIG. 38 ; 138 ). A method according to claim 19, characterized in that in step A) in addition to the retaining ring ( 54 ; 154 ) a reinforcing disk ( 44 ; 144 ) in the injection mold ( 82 . 86 . 90 . 92 . 96 ) is fixed. Method according to claim 20, characterized in that the reinforcing disk ( 44 ; 144 ) Holding recesses, in which retaining pin ( 84 ) for fixing in the injection mold ( 82 . 86 . 90 . 92 . 96 ) intervene. Method according to one of claims 19 to 21, characterized in that in step A) in addition to the retaining ring ( 154 ) a support ring ( 178 ) in the injection mold ( 82 . 86 . 90 . 92 . 96 ) is fixed. Method according to one of claims 19 to 22, characterized in that the biasing means cavity in the retaining ring ( 54 ; 154 ) as Axialumfangsnut ( 56 ; 156 ) is trained.