DE102017008854B4 - Bleeding valve for venting hydraulic actuation systems in motor vehicles - Google Patents

Abstract

Vent valve (10) for venting hydraulic actuation systems in motor vehicles, with a housing section (12) which has a receiving bore (14) which defines a rotation axis (16) about which a vent body (18) which is axially fixedly received in the receiving bore (14) and which has a vent bore (20) can be rotated, and a sealing element (22) which seals between the housing section (12) and the vent body (18), wherein the vent bore (20) can be optionally connected to a vent groove (24) between the housing section (12) and the vent body (18) by rotating the vent body (18) about the rotation axis (16) in order to open the vent valve (10), characterized in that the vent groove (24) is provided in the sealing element (22), which is designed as an annular body with an inner circumferential surface (72), a Outer peripheral surface (74) and an end face (76) facing away from the vent body (18), wherein the vent groove (24) extends from the end face (76) to the inner peripheral surface (72) of the sealing element (22) and forms a sealing edge (26) which runs parallel to the axis of rotation (16).

Description

TECHNICAL FIELD

The present invention relates to a vent valve for venting hydraulic actuation systems according to the preamble of patent claim 1. In particular, the invention relates to a vent valve for venting hydraulic systems for the actuation of clutches and brakes in motor vehicles, as they are used en masse in the automotive industry.

STATE OF THE ART

During initial filling, fluid change or other maintenance or repair work, hydraulic systems usually have to be vented manually. For this purpose, vent valves are used which have a housing section connected to a pressure medium line with a recess in which a venting element is accommodated. The venting element can usually be rotated about a rotation axis from a closed position to a venting position or vice versa, so that a sealing seat arranged between the venting element and the housing section, which seals the hydraulic system against the environment, can be opened or closed. To vent the hydraulic system, pressure is usually applied to the hydraulic system and the vent valve arranged at a high point of the hydraulic system is opened by turning the venting element to the venting position in order to drain off the air to be removed and excess pressure medium. After venting, the venting element is turned back to the closed position so that the vent valve can withstand the operating pressure of the hydraulic system again. Depending on the application, the vent valve can either have its own valve housing or be integrated into a housing section of a hydraulic cylinder, e.g. a slave cylinder, or another hydraulic assembly.

From the publication EP 1 811 213 A2 an axially sealing venting device is known in which a sealing element is provided for sealing between a housing having a recess and a venting element, the latter being inserted in the recess of the housing and secured there against axial movements, but also rotatable about an axis of rotation. In the housing and in the venting element, axial venting holes are arranged coaxially with one another, with the recess in the housing and with the axis of rotation. According to an essential aspect of this prior art, the sealing element is inserted in the housing in a non-rotatable manner in a sealing manner and has a through hole that is eccentric with respect to the axis of rotation but parallel to it, which in a venting position is axially aligned with a correspondingly eccentrically arranged channel with a tapered cross-section of the venting hole in the venting element. In a sealed position of the venting element, however, the sealing element is pressed against the venting element in a self-reinforcing sealing manner under the influence of the pressure medium with a sealing surface facing the venting element.

In order to ensure the function of this venting device, relatively tight dimensional and positional tolerances of the recess in the housing, the venting element and the sealing element must be maintained, which requires a certain amount of manufacturing effort, particularly if venting and sealing elements of the same type are to be used in different housings as part of a modular system.

Furthermore, from the document forming the preamble of patent claim 1 DE 101 55 793 A1 Vent valves are known in which, when the vent valve is in a sealed state, the respective vent element (vent plug in the language used in this publication) and the associated housing are radially sealed against one another. In all embodiments disclosed in this publication, the vent flow is diverted from an axial course into at least one approximately radial course in the region of a vent bore section of the vent element that extends transversely to the axis of rotation of the vent element and that passes over a sealing edge that runs obliquely to the axis of rotation of the vent element for sealing.

In the embodiment according to 1 In this state of the art, an O-ring is provided as a sealing element, which is inserted in an elliptical circumferential groove of the venting element. Due to the deformation of the originally round O-ring, the O-ring is unstable in the pre-assembled state, so that it can easily slide off the venting elements with O-rings in a loose container. In addition, when the venting element is axially assembled in the associated recess of the housing, locally different pressures of the O-ring and associated sealing problems can occur. In addition, when the venting element is rotated into the venting position, the O-ring is moved over a venting gap in the housing wall, so that it can be damaged in the process. In particular, if the hydraulic system is under increased pressure during the venting process, the O-ring can be pressed into the venting gap (gap extrusion) and damaged/sheared off during the subsequent closing process.

In another embodiment, 3 In this publication, the sealing element is designed as a hose section and is arranged in a gap between a cylindrical inner surface of the housing and a cylindrical outer surface of the venting element. In order to seal reliably between these two surfaces, the wall thickness of the hose section must be larger than the gap, so that either the venting element with the sealing element pre-mounted on it must be pressed into the recess of the housing or the venting element must be pressed into the sealing element pre-mounted in the recess of the housing, both of which require a considerable amount of force. In addition to making assembly more difficult, this can also cause damage to the hose section that impairs the sealing function.

A particular problem is the one in the publication DE 101 55 793 A1 A further disadvantage of the vent valves disclosed is that a relatively large angle of rotation of the vent element with respect to the recess in the housing is required in order to rotate the vent element from the completely sealed closed position to the completely open vent position and back again, with the vent valve being partially open over a relatively large angular range in between. This is particularly disadvantageous in the case of concealed actuation, confined spaces or in places that are difficult to access, since (further) rotation of the vent element may require re-gripping (if at all possible) while the vent valve is partially open and leaking, which precludes the use of these previously known vent valves in certain applications.

In this context, the publication JP S61- 55 475 A a vent plug with a valve section at the free end. An external thread section is provided on the outer circumference of the vent plug, which is screwed into an internal thread section in a stepped connecting bore of a cylinder housing. By rotating the vent plug about a rotation axis, a tapered end part of the valve section can be axially displaced against a complementary seat surface in the stepped connecting bore in order to seal liquid-tight between the vent plug and the cylinder housing. Furthermore, the external thread section of the vent plug is provided with a U-shaped longitudinal groove, seen in a plan view, in which a radially extending bore opens in an unclosable manner, which in turn communicates with an axial blind bore in the vent plug. A separate sealing element is not provided in this prior art.

From the publication FR 3 048 744 A1 Furthermore, a venting system is known which generally comprises a housing, a vent plug inserted therein and a seal. The housing comprises a socket section in which a plug section of the vent plug is mounted so as to be rotatable about an axis of rotation. The seal with a lower sealing section and an upper sealing section is arranged between the socket section of the housing and the plug section of the vent plug. The upper sealing section ensures the seal between the housing and the vent plug, regardless of the rotational position of the vent plug about its axis of rotation. The vent plug also has a central vent channel which extends along the axis of rotation and a connecting section communicating therewith which runs at right angles to the axis of rotation at the level of the lower sealing section.

When the seal is mounted in the housing, the lower sealing section is formed asymmetrically in relation to the axis of rotation and has a cross-section with an inner contour that is made up of a semicircle and a semi-ellipse. In this state of the art, the individual areas on the inner circumference of the lower sealing section therefore merge seamlessly into one another. The plug section of the vent plug rests with one half of its cross-section against a semi-cylindrical sealing area of the lower sealing section, while - due to the semi-elliptical shape of the inner contour of the lower sealing section - a crescent-shaped free space remains on the opposite side of the cross-section of the plug section of the vent plug. Depending on the rotational position of the vent plug around the axis of rotation, a connection can be made via this free space between the connecting section communicating with the vent channel and a channel in the housing. However, this requires a relatively large relative rotation between the vent plug and the housing around the axis of rotation in order to switch between the connected and separated states.

The same applies to the publication EP 1 978 271 A2 revealed A venting device having a main body having two openings and an oil channel therebetween, each of the openings being connectable to an oil line of a hydraulic clutch actuator. This venting device further comprises a vent plug received in a stepped passage in the main body, the smallest diameter portion of the passage in the main body forming part of the oil channel. In a region of the passage having a medium diameter, an outlet is provided which runs at right angles to the passage and in which the oil channel continues.

In this prior art, a rubber seal is provided for sealing between the main body and the vent plug. The latter rests against a step towards the smallest diameter area of the passage and has a hole and a conical, inner circumferential surface. The inner circumferential surface forms a stop and a sealing surface for a conical outer circumferential surface on the end of the vent plug facing the hole, which slides in the rubber seal.

In a part of the rubber seal facing the outer peripheral surface of the vent plug, a channel is formed in a part of the rubber material that extends along the center line of the vent plug. The above-mentioned oil channel that connects the openings of the venting device therefore runs through the hole, the rubber seal and the channel in the rubber seal. The hole and thus the oil channel between the two openings can be closed by means of the vent plug that can be moved longitudinally in the rubber seal, namely by longitudinally moving the vent plug in the rubber seal until the vent plug comes into sealing contact with its outer peripheral surface on the inner peripheral surface of the rubber seal.

The vent plug also has a vent hole running along the central axis with an open end formed by a hole running at right angles to the central axis, which, when the vent plug is installed, is located at the level of the side outlet from the passage to the oil channel or at the level of the above-mentioned channel in the rubber seal. The vent plug can be rotated around the central axis of the vent plug with respect to the rubber seal and, depending on the rotational position, can open or close a connection between the oil channel and the vent hole.

TASK

The invention is based on the prior art according to the document DE 101 55 793 A1 The aim of the invention is to create a vent valve for venting hydraulic actuation systems in motor vehicles, which avoids the above disadvantages and, compared to the described state of the art, can be operated as easily and reliably as possible in a wide variety of installation situations with small angles of rotation of the vent body.

PRESENTATION OF THE INVENTION

This object is achieved by the features specified in patent claim 1. Advantageous or expedient developments of the invention are the subject of patent claims 2 to 14.

In a vent valve for venting hydraulic actuation systems in motor vehicles, comprising a housing section which has a receiving bore which defines an axis of rotation about which a vent body which is axially fixedly received in the receiving bore and has a vent bore can be rotated, and a sealing element which seals between the housing section and the vent body, wherein the vent bore can be optionally connected to a vent groove between the housing section and the vent body by rotating the vent body about the axis of rotation in order to open the vent valve; according to the invention, the vent groove is provided in the sealing element which is designed as an annular body with an inner peripheral surface, an outer peripheral surface and an end face facing away from the vent body, wherein the vent groove extends from the end face on the inner peripheral surface of the sealing element and forms a sealing edge which runs parallel to the axis of rotation.

In contrast to the state of the art, as represented by the 3 the printed matter DE 101 55 793 A1 is represented, according to which the sealing edge is formed by a sealing hose cut at an angle to the axis of rotation of the venting element, the venting groove is thus integrated in the sealing element in the venting valve according to the invention, in such a way that the sealing edge defined by the venting groove does not run at an angle to the axis of rotation of the venting body. The term "sealing edge" is understood here to mean the transition area between the venting groove and the peripheral surface of the sealing element, which is passed over by the venting hole in the venting body when the venting body is rotated in the receiving hole of the housing section. and thus forms the entrance and exit of the sealing area.

Because this transition region according to the invention is aligned parallel to the axis of rotation, the angle of rotation of the vent body required to travel over the transition region is reduced or minimized - compared to an obliquely running transition region as is the case in the generic prior art - namely to the maximum angle that the edge of the vent hole encloses with respect to the axis of rotation. In other words, the vent body only has to be rotated at the sealing edge of the sealing element by the width of the vent hole in the vent body in order to go from a maximum connection cross-section between the vent hole and the vent groove in a fully open state of the vent valve to an interruption or separation of the connection between the vent hole and the vent groove and thus a closed state of the vent valve, and vice versa. This is particularly advantageous if the vent valve is to be used in a location that is difficult to access, because even a small (rotary) movement of the vent body is enough to close (or open) the vent valve, and after (or before) any subsequent gripping to turn the vent body into an end position can be carried out without worrying about unwanted leaks. In addition, the smaller effective actuation angle of the vent body compared to the state of the art basically allows the vent valve to be used in combination with relatively firm or permanently mounted vent hoses that can or may only be twisted minimally.

Further advantages of the vent valve according to the invention result from the fact that the vent groove is provided in the sealing element - and not in the housing section, as in the generic prior art. On the one hand, the vent groove in the sealing element forms a type of desired deformation point or represents a certain local weakening of the material, which simplifies the installation of the sealing element in the receiving bore of the housing section. On the other hand, sharp edges on the housing section are avoided in this way, as are to be expected when the vent groove is formed in the housing section and which can cause damage to the sealing element during installation or operation.

Furthermore, the fundamentally radial sealing of the vent valve according to the invention compared to an axially sealing vent valve eliminates the need for close dimensional and/or positional tolerances of the components involved in the axial direction.

The fact that the sealing element is designed as an annular body with an inner circumferential surface, an outer circumferential surface and an end face facing away from the vent body, with the vent groove extending from the end face to the inner circumferential surface of the sealing element, makes it easy to manufacture. In comparison to an arrangement in which a vent groove extending from the end face would extend along the outer circumferential surface of the sealing element and could be connected to the vent hole of the vent body via a connecting hole in the sealing element, the arrangement is also highly reliable (no weakening of the sealing element in the area of a connecting hole).

To locally increase the preload, the sealing element can have at least one circumferential sealing bead on the inner circumferential surface and/or the outer circumferential surface. Such a sealing bead makes it possible to create a highly dense, "pressed" line contact with the respective counter surface, similar to an O-ring. The sealing element can preferably have two circumferential sealing beads on the inner circumferential surface, which are spaced apart from one another along the axis of rotation, whereby an increase in the tightness corresponding to the respective tightness requirements can easily be achieved. In a preferred embodiment, one of the sealing beads on the inner circumferential surface of the sealing element can be formed at an end of the sealing element facing away from the front side of the sealing element in order to seal at the front against the environment.

Depending on the respective sealing requirements, the sealing element can (also) have two circumferential sealing beads on the outer circumferential surface, which are spaced apart from one another along the axis of rotation, in order to increase the sealing in a simple manner. A sealing bead on the outer circumferential surface of the sealing element can also be provided in a preferred arrangement close to the front side of the sealing element and serve to press the sealing element against a bottom section of the vent body in order to reliably prevent hydraulic fluid under pressure from entering a gap between the receiving bore and the sealing element. Finally, in connection with the optional sealing beads, it is particularly preferred if a sealing bead on the inner circumferential surface of the sealing element and a sealing bead on the outer circumferential surface of the sealing element are arranged in an imaginary common plane which is transverse to the The axis of rotation is located in a rotationally symmetrical area of the sealing element outside the venting groove. The two-sided (radially inside/outside) formation of the sealing beads in an area with the same material distribution all around creates a particularly uniform tensioning of the sealing element from both sides, which makes the arrangement particularly fail-safe and leak-proof.

In principle, it is conceivable to fix the sealing element in the housing section in a force-fitting manner, e.g. by clamping a flange or the like, in a material-fitting manner, e.g. by spraying the sealing material onto the housing section, or by means of an adhesive connection. However, particularly with regard to simple manufacture and assembly as well as the possibility of replacement in the event of damage, it is preferred if the sealing element is fixed in the housing section in a form-fitting manner. In a preferred embodiment, the sealing element can have an orientation extension that differs from the rotational shape for the angle of rotation orientation in the housing section and is accommodated in a complementary recess in the housing section. Such an extension can be easily formed in an injection mold and is therefore also conducive to simple manufacture of the sealing element.

In principle, the venting groove in the sealing element can have any cross-sectional geometry, e.g. it can be rectangular or triangular in cross-section. However, particularly with a view to achieving the highest possible tear resistance of the sealing element, it is preferred if the venting groove has a semicircular cross-section. Such a cross-sectional shape of the venting groove ensures - in the absence of sharp edges compared to a square cross-sectional shape - a particularly even distribution of stress along the groove wall.

Furthermore, it is possible to provide a direct vent hole in the vent body that runs obliquely with respect to the axis of rotation of the vent body or a vent hole with a curved course. However, particularly with regard to simple manufacture and high part strength, it is preferred if the vent hole of the vent body has a blind hole section that runs along the axis of rotation and intersects a blind hole section of the vent hole that runs transversely to the axis of rotation.

For axially fixed, yet rotatable mounting of the vent body in the mounting hole, a snap connection is conceivable, for example with spring-loaded snap lugs on the vent body and an associated radial groove in the mounting hole of the housing section. Particularly with regard to the possibility of replacing the vent body and/or the sealing element, as well as in the case of complex housings on which a snap geometry with an undercut would be difficult to form - for example by forced demolding or with the aid of cross slides - it is preferred if the vent valve has a securing element that holds the vent body axially fixed in the mounting hole of the housing section, but still allows the vent body to rotate in the mounting hole.

In an advantageous embodiment of the vent valve, the vent body can also have a nose-shaped section which can be brought into contact with a stop surface provided on the housing section when the vent valve reaches a closed position. In this way, a clear end position of the vent body in the housing section is advantageously specified, which is particularly helpful when operating the vent valve when it is used in a location that is difficult to access or see.

Finally, in a particularly advantageous embodiment of the vent valve, a locking device can be provided between the vent body and the housing section, which serves to lock the vent body in the closed position of the vent valve relative to the housing section. This measure enables a haptic indication of the closed position of the vent valve, which in turn is advantageous when it is used in a location that is difficult to access or see. For example, a concealed overhead operation of the vent valve is easily possible, and the locking device can easily prevent the vent valve from opening unintentionally.

SHORT DESCRIPTION OF THE DRAWINGS

• 1 eine nach unten abgebrochene, perspektivische Ansicht eines an einem Gehäuseabschnitt etwa eines Zylindergehäuses vorgesehenen Entlüftungsventils zum Entlüften eines hydraulischen Systems für z.B. die Betätigung einer Kupplung nach einem bevorzugten Ausführungsbeispiel der Erfindung von schräg oben und in einem geschlossenen Zustand des Entlüftungsventils, in dem sich ein in einer Aufnahmebohrung des Gehäuseabschnitts um eine Rotationsachse verdrehbar aufgenommener, in der Aufnahmebohrung durch ein Sicherungselement axial festgelegter Entlüfterkörper in einer gegenüber dem Gehäuseabschnitt verrasteten Drehendstellung befindet;
• 2 eine nach unten abgebrochene Längsschnittansicht des Entlüftungsventils gemäß 1 mit Schnittverlauf entlang der Rotationsachse des Entlüfterkörpers, wobei sich das Entlüftungsventil in dem geschlossenen Zustand von 1 befindet, in dem ein zwischen dem Entlüfterkörper und dem Gehäuseabschnitt in der Aufnahmebohrung angeordnetes Dichtelement eine Verbindung zwischen dem hydraulischen System und der Umgebung unterbricht;
• 3 eine Schnittansicht des Entlüftungsventils gemäß 1 entsprechend der Schnittverlaufslinie III-III in 2, mit Blick auf eine zwischen dem Entlüfterkörper und dem Gehäuseabschnitt vorgesehene Rasteinrichtung, die dazu dient, den Entlüfterkörper in dem geschlossenen Zustand des Entlüftungsventils gegenüber dem Gehäuseabschnitt zu verrasten;
• 4 eine Schnittansicht des Entlüftungsventils gemäß 1 entsprechend der Schnittverlaufslinie IV-IV in 2, mit Blick auf das Sicherungselement zur axialen Festlegung des Entlüfterkörpers in der Aufnahmebohrung des Gehäuseabschnitts;
• 5 eine Schnittansicht des Entlüftungsventils gemäß 1 entsprechend der Schnittverlaufslinie V-V in 2, insbesondere zur Veranschaulichung, wie das Dichtelement formschlüssig gegen ein Verdrehen um die Rotationsachse in der Aufnahmebohrung des Gehäuseabschnitts gesichert ist;
• 6 eine Schnittansicht des Entlüftungsventils gemäß 1 entsprechend der Schnittverlaufslinie VI-VI in 2, insbesondere zur Illustration, wie in dem geschlossenen Zustand des Entlüftungsventils ein quer zur Rotationsachse verlaufender Sackbohrungsabschnitt einer Entlüftungsbohrung im Entlüfterkörper bezüglich einer parallel zur Rotationsachse verlaufenden Entlüftungsnut im Dichtelement um die Rotationsachse im Winkel ausgerichtet ist;
• 7 eine hinsichtlich Schnittverlauf und Maßstab der 2 entsprechende Längsschnittansicht des Entlüftungsventils gemäß 1 in einem geöffneten Zustand, in dem die Entlüftungsnut im Dichtelement eine Verbindung zwischen dem hydraulischen System und der Umgebung über die Entlüftungsbohrung in dem Entlüfterkörper ermöglicht;
• 8 eine im Maßstab gegenüber der 2 vergrößerte Draufsicht auf das Dichtelement des Entlüftungsventils gemäß 1;
• 9 eine Schnittansicht des Dichtelements des Entlüftungsventils gemäß 1 entsprechend der Schnittverlaufslinie IX-IX in 8 und im Maßstab der 8; und
• 10 eine im Maßstab der 8 entsprechende Untersicht auf das Dichtelement des Entlüftungsventils gemäß 1, mit Blick auf die Entlüftungsnut.

In the following, the invention is explained in more detail using a preferred embodiment with reference to the attached, partially schematic drawings, in which elastomeric or elastic parts are shown in the undeformed state to simplify the illustration. In the drawings:

• 1 a perspective view, broken down at the bottom, of a vent valve provided on a housing section of a cylinder housing for venting a hydraulic system for e.g. the actuation of a clutch according to a preferred embodiment of the invention, from obliquely above and in a closed state of the A vent valve in which a vent body which is received in a receiving bore of the housing section so as to be rotatable about an axis of rotation and is axially fixed in the receiving bore by a securing element is located in a rotational end position locked relative to the housing section;
• 2 a longitudinal sectional view of the vent valve according to 1 with section along the axis of rotation of the vent body, whereby the vent valve in the closed state of 1 in which a sealing element arranged between the vent body and the housing section in the receiving bore interrupts a connection between the hydraulic system and the environment;
• 3 a sectional view of the vent valve according to 1 according to the section line III-III in 2 , with a view to a locking device provided between the vent body and the housing section, which serves to lock the vent body relative to the housing section in the closed state of the vent valve;
• 4 a sectional view of the vent valve according to 1 according to the section line IV-IV in 2 , with a view of the locking element for axially fixing the breather body in the receiving bore of the housing section;
• 5 a sectional view of the vent valve according to 1 according to the section line VV in 2 , in particular to illustrate how the sealing element is positively secured against rotation about the axis of rotation in the receiving bore of the housing section;
• 6 a sectional view of the vent valve according to 1 according to the section line VI-VI in 2 , in particular to illustrate how, in the closed state of the vent valve, a blind bore section of a vent bore in the vent body running transversely to the axis of rotation is aligned at an angle around the axis of rotation with respect to a vent groove in the sealing element running parallel to the axis of rotation;
• 7 a regarding cutting line and scale of the 2 corresponding longitudinal sectional view of the vent valve according to 1 in an open state in which the vent groove in the sealing element enables a connection between the hydraulic system and the environment via the vent hole in the vent body;
• 8 one in scale compared to the 2 enlarged top view of the sealing element of the vent valve according to 1 ;
• 9 a sectional view of the sealing element of the vent valve according to 1 according to the section line IX-IX in 8 and on the scale of 8 ; and
• 10 one in the scale of 8 corresponding bottom view of the sealing element of the vent valve according to 1 , looking at the vent groove.

DETAILED DESCRIPTION OF THE EMBODIMENT

In the 1 to 7 The reference number 10 generally designates a vent valve for venting hydraulic systems for the operation of, for example, clutches or brakes in motor vehicles. The vent valve 10 has a housing section 12, which is, for example, part of a separate valve housing in the hydraulic system or can be formed integrally with a housing of a hydraulic component, such as a cylinder housing of a hydraulic cylinder of the hydraulic system. The housing section 12 has a receiving bore 14 or recess, which defines a rotation axis 16, about which a vent body 18, which is axially fixedly received in the receiving bore 14 and is provided with a vent bore 20 or a vent channel, can be rotated. The vent valve 10 also has a 8 to 10 Sealing element 22, shown separately and described in detail below, which seals between the housing section 12 and the vent body 18.

By rotating the vent body 18 about the rotation axis 16, the vent hole 20 can optionally be connected to a vent groove 24 between the housing section 12 and the vent body 18 in order to open the vent valve 10, as shown in 7 shown, and thus to connect the hydraulic system with the environment and to vent it. In the 2 In the position of the vent valve 10 shown, however, the vent body 18 is rotated relative to the housing section 12 such that the sealing element 22 arranged between the housing section 12 and the vent body 18 separates the hydraulic system from the environment in a fluid-tight and air-tight manner. It is essential that, as will also be explained in more detail below, the vent groove 24 is provided in the sealing element 22 and forms at least one sealing edge 26 which runs parallel to the axis of rotation 16 of the vent body 18.

According in particular to the 1 , 2 and 7 In the illustrated embodiment, the The housing section 12 of the vent valve 10, which is made of suitable plastic and is preferably injection-molded, has a substantially hollow-cylindrical shape and delimits the receiving bore 14 on the inner circumference, which is stepped several times to accommodate the vent body 18 and the sealing element 22. The sealing element 22, which is made of a rubber-elastic material, is secured in the receiving bore 14 in a form-fitting manner against rotation about the axis of rotation 16, as described with reference to the 5 will be described in more detail. In the axial direction of the housing section 12, the sealing element 22 is held in the receiving bore 14 between steps of the receiving bore 14 and the vent body 18. The vent body 18, which is also made of a suitable plastic and is preferably formed by injection molding, is held axially fixed in the receiving bore 14 by means of a metallic, clip-like securing element 28, which nevertheless allows the vent body 18 to rotate in the receiving bore 14.

In the 2 and 7 In the upper, largest diameter area of the receiving bore 14 in the housing section 12, the vent body 18 is guided in rotation with essentially no play via a guide section 30 of the vent body 18 which is complementary to the receiving bore 14 and is cylindrical on the outer circumference. As can also be seen from the 1 , 2 , 4 and 7 The housing section 12 is provided with two through-holes 34 for axially securing the vent body 18 in the receiving bore 14, starting from an outer groove 32 in the same cross-sectional plane, each of which is used to receive a leg 36 of the vent body 18 in a plan view ( 4 ) essentially serve as a U-shaped securing element 28 which is bent at the legs 36 in the manner of a hairpin spring according to DIN 11024. In this case, an arcuate base section 38 of the securing element 28 connecting the legs 36 is in accordance with the 1 and 4 received substantially flush with the outer circumference of the housing section 12 in the outer groove 32 of the housing section 12.

The legs 36 themselves engage in a form-fitting manner in a circumferential groove 40 formed on the vent body 18, the width of which is determined according to the 2 and 7 is slightly larger than the diameter of a spring steel wire from which the securing element 28 is made. The groove depth of the circumferential groove 40 in the vent body 18 varies according to 4 over the circumference of the vent body 18 in a mirror-symmetrical manner with respect to an imaginary plane containing the axis of rotation 16 of the vent body 18, in such a way that the legs 36 of the securing element 28 in the rotational end positions of the vent body 18, ie in the fully open ( 7 ) or completely closed ( 2 ) position of the vent valve 10 at the lowest point of the circumferential groove 40 on the vent body 18. This results in spring-loaded rotational end positions of the vent body 18 in the receiving bore 14 of the housing section 12 by means of the securing element 28, from which the vent body 18 can only be rotated out by elastically spreading the securing element 28, i.e. by overcoming a spring resistance by the securing element 28. In other words, when the vent body 18 is close to one of its two rotational end positions, the spring force of the securing element 28 causes a torque about the rotation axis 16 on the vent body 18, which promotes or facilitates further rotation of the vent body 18 into the respective rotational end position.

Above the rotary guide area for the vent body 18, the housing section 12 is provided at its open end with a ring-segment-shaped extension 42 which extends in the axial direction and is bevelled at 45° on the inner circumference towards the receiving bore 14. The extension 42 forms flat stop surfaces 44, 46 for the vent body 18 on both sides, which according to 3 in a common plane parallel to the axis of rotation 16. In order to be able to interact with these stop surfaces 44, 46, the vent body 18 has a nose-shaped section 48 which, when the closed position of the vent valve 10 is reached (see the 1 and 3 ) or when the open position of the vent valve 10 is reached, it can be brought into contact with the respective stop surface 44 or 46 provided on the housing section 12. The stop surfaces 44, 46 limit the possible angle of rotation of the vent body 18 in the receiving bore 14 about the rotation axis 16 to 180°.

As in particular the 1 shows, the nose-shaped section 48 is directly connected to a handling section 50 of the vent body 18, with which the vent body 18 protrudes above its guide section 30 from the receiving bore 14 of the housing section 12. According in particular to the 1 and 3 the handling section 50 is flattened on both sides of the nose-shaped section 48, also to facilitate manual rotation of the vent body 18 with respect to the housing section 12. The 1 at 52 The (partial) ribbing of the handling section 50 shown provides a certain grip when manually turning the vent body 18 in the receiving bore 14, particularly in oily environments, and at the same time meets the requirement that, for problem-free injection molding from plastic, the wall thicknesses should be as uniform as possible in each zone.

The 1 and 3 It can also be seen that a locking device 54 is provided between the vent body 18 and the housing section 12, which serves to lock the vent body 18 in the closed position of the vent valve 10 relative to the housing section 12. In the embodiment shown, the locking device 54 has a locking bevel projection 56 near the stop surface 44, which projects raised above a flat, ring-segment-shaped end face 58 of the housing section 12 when viewed from above, which extends perpendicular to the axis of rotation 16 and in the circumferential direction around the axis of rotation 16 between the stop surfaces 44, 46 of the extension 42. The nose-shaped section 48 of the vent body 18 acts via a 1 lower surface area 60 with the locking bevel projection 56 in order to hold the nose-shaped section 48 in the locked state of the vent body 18 between the stop surface 44 on the extension 42 and the locking bevel projection 56 of the front surface 58. The axial tolerances and elasticities are selected in such a way that the surface area 60 of the nose-shaped section 48 in interaction with the locking bevel projection 56 of the front surface 58 resists a twisting movement of the vent body 18 about the axis of rotation 16 into (or out of) the 1 shown closed position(s) without causing plastic deformations of the components involved. The user of the vent valve 10 thus receives a haptic indication of when the definitively closed state of the vent valve 10 is present or is being left when the vent valve 10 is actuated.

On the side of the handling section 50 facing away from the guide section 30 of the vent body 18, there is a connection section 62 of the vent body 18, which extends coaxially to the guide section 30 away from the handling section 50. In the embodiment shown, the connection section 62 is designed in the manner of a hose connector with an insertion bevel and undercut, so that a hose (not shown) can be attached to the connection section 62 in a manner known per se, e.g. with a hose clamp (not shown).

Furthermore, in particular the 2 and 7 show, the vent hole 20 of the vent body 18 has a blind hole section 64 running along the rotation axis 16, which intersects a further blind hole section 66 of the vent hole 20 running transversely to the rotation axis 16. While the blind bore section 64 extends from the connection section 62 through the handling section 50, the guide section 30 and a sealing section 68 of the vent body 18 to close to a closed end of the vent body 18 facing away from the connection section 62, the further blind bore section 66 runs in the region of the sealing section 68 close to the end of the vent body 18 facing away from the connection section 62. The blind bore section 64 and the further blind bore section 66 thus form an angular shape of the vent bore 20. The sealing section 68 of the vent body 18, which protrudes from the guide section 30 on the side of the guide section 30 facing away from the handling section 50 along the axis of rotation 16, is according to the 2 and 7 substantially cup-shaped, with a cylindrical outer peripheral surface 70 and a bottom portion 71, which interact with the sealing element 22 as described below.

Further details of the sealing element 22 and its mounting position and function are given in the 2 and 5 to 10 As can be seen in the 8 to 10 As can be seen, the sealing element 22 is designed as an annular body, with an inner peripheral surface 72, an outer peripheral surface 74 and an end face 76 facing away from the vent body 18, wherein the aforementioned venting groove 24 extends from the end face 76 on the inner peripheral surface 72 of the sealing element 22.

As already mentioned, the sealing element 22 is fixed in the housing section 12 of the vent valve 10 in a form-fitting manner. In this case, the sealing element 22 has an orientation extension 78 which deviates from the rotational shape in order to orient the angle of rotation about the rotation axis 16 in the housing section 12 and which is accommodated in a complementarily shaped recess 80 in the housing section 12. As can be seen in particular from the 8 to 10 show, the orientation extension 78 of the sealing element 22 is formed by a ring-like, axial extension of the sealing element 22, the circular ring shape of which is flattened at the reference numerals 82 on two sides at an angle of 90°. The flattenings 82 run in the top view or bottom view according to the 8 and 10 viewed essentially tangentially to the otherwise cylindrical outer peripheral surface 74 of the sealing element 22. The orientation extension 78 simultaneously fixes the sealing element 22 in the axial direction of the housing section 12 through its axial position between the guide section 30 of the vent body 18 and a step 84 of the receiving bore 14.

Furthermore, particular attention is paid to 8 to 10 It can be seen that the sealing element 22 in the illustrated embodiment is provided with two circumferential sealing beads 86, 88, 90, 92 on both its hollow cylindrical inner peripheral surface 72 and its outer peripheral surface 74. is. According to 9 the sealing beads 86, 88 provided on the inner circumferential surface 72 of the sealing element 22 are spaced apart from one another along the rotation axis 16 of the vent body 18. Likewise, the sealing beads 90, 92 formed on the outer circumferential surface 74 of the sealing element 22 are spaced apart from one another along the rotation axis 16 of the vent body 18.

As regards the more precise axial position of the spherical sealing beads 86, 88, 90, 92 seen in cross-section, it should be noted that one - namely the one in the 2 , 7 and 9 upper sealing bead 86 - of the sealing beads 86, 88 on the inner circumferential surface 72 of the sealing element 22 is formed at an end of the sealing element 22 facing away from the end face 76 of the sealing element 22. One - namely the one in the 2 , 7 and 9 lower sealing bead 92 - the sealing bead 90, 92 on the outer peripheral surface 74 of the sealing element 22, however, is provided near the front side 76 of the sealing element 22 and serves in cooperation with a hollow cylindrical sealing surface section 94 of the receiving bore 14 to press the sealing element 22 onto the bottom section 71 of the vent body 18. The other, in the 2 , 7 and 9 The lower sealing bead 88 on the inner circumferential surface 72 of the sealing element 22 and the further, in said figures upper sealing bead 90 on the outer circumferential surface 74 of the sealing element 22 are finally arranged in an imaginary common plane, which runs transversely to the axis of rotation 16 of the vent body 18 in a rotationally symmetrical area of the sealing element 22 outside the vent groove 24. In the latter area, the strongest pressing of the mounted sealing element 22 with the respective counter surfaces on the receiving bore 14 and vent body 18 takes place. According to the 2 , 7 and 9 the venting groove 24 extending from the front side 76 of the sealing element 22 ends just in front of this area, with a flat end surface extending transversely to the axis of rotation. As a result, the sealing beads 86, 88, 90, 92 in conjunction with their respective counter surfaces on the vent body 18 (sealing section 68) or in the receiving bore 14 (sealing surface section 94) ensure in a permanently reliable manner that there is no unwanted leak past the sealing element 22.

The 9 and 10 also show that the groove depth of the venting groove 24 corresponds to approximately half the material thickness of the sealing element 22 in the axial region of the venting groove 24. In the embodiment shown, the venting groove 24 has a semicircular cross-section, as in 10 can be seen. Finally, it is evident from these figures in particular that the venting groove 24 is formed in the inner circumferential surface 72 of the sealing element 22 in such a way that it forms a straight sealing edge 26 on both sides of the groove with the inner circumferential surface 72, extending parallel to the central axis of the sealing element 22.

In the 7 In the fully open position of the vent valve 10 shown, the blind bore section 66 of the vent bore 20 in the vent body 18 is aligned with the vent groove 24 in the sealing element 22. Accordingly, the hydraulic system can communicate with the environment via a passage 96 in the housing section 12, a portion of the receiving bore 14 below the sealing element 22, the vent groove 24, the blind bore section 66 and finally the blind bore section 64 of the vent bore 20 from the connection section 62 of the vent body 18. Air trapped in the hydraulic system can escape in this way via the vent valve 10 located at a high point.

If the vent body 18 in the receiving bore 14 of the housing section 12 is only a few degrees around the axis of rotation 16 from the 7 shown position, the blind bore section 66 of the vent hole 20 passes over the sealing edge 26 on the sealing element 22 until the blind bore section 66 is completely covered by the inner circumferential surface 72 of the sealing element 22. This interrupts the previously described connection between the hydraulic system and the environment. In the position shown in 1 In the closed position of the vent valve 10 locked by means of the locking device 54, the blind bore section 66 of the vent bore 20 of the vent groove 24 in the sealing element 22 is approximately diametrically opposite with respect to the axis of rotation 16, as in 2 The vent valve 10 is thus completely closed air- and fluid-tight.

A vent valve for venting hydraulic systems has a housing section that has a receiving bore that defines a rotation axis. A vent body is axially fixed in the receiving bore, which can nevertheless be rotated about the rotation axis and has a vent bore. The vent valve also comprises a sealing element that seals between the housing section and the vent body. By rotating the vent body, the vent bore can optionally be connected to a vent groove between the housing section and the vent body in order to open the vent valve and thus establish a connection between the hydraulic system and the environment. In order to close the vent valve, the connection between the vent bore and the vent groove can also be separated again by rotating the vent body. The vent groove is provided in the sealing element and forms a sealing edge that runs parallel to the rotation axis. axis so that the vent valve can be opened or closed with small angles of rotation of the vent body.

REFERENCE SYMBOL LIST

10

vent valve

12

housing section

14

mounting hole

16

axis of rotation

18

vent body

20

vent hole

22

sealing element

24

vent groove

26

sealing edge

28

securing element

30

leadership section

32

outer groove

34

piercing

36

leg

38

base section

40

circumferential groove

42

appendix

44

stop surface

46

stop surface

48

nose-shaped section

50

handling section

52

ribbing

54

locking device

56

locking bevel projection

58

frontal surface

60

surface area

62

connecting section

64

blind bore section

66

blind bore section

68

sealing section

70

outer peripheral surface

71

floor section

72

inner peripheral surface

74

outer peripheral surface

76

front side

78

orientation process

80

recess

82

flattening

84

Level

86

sealing bead

88

sealing bead

90

sealing bead

92

sealing bead

94

sealing surface section

96

passage

Claims (14)

Vent valve (10) for venting hydraulic actuation systems in motor vehicles, with a housing section (12) which has a receiving bore (14) which defines a rotation axis (16) about which a vent body (18) which is axially fixedly received in the receiving bore (14) and has a vent bore (20) can be rotated, and a sealing element (22) which seals between the housing section (12) and the vent body (18), wherein the vent bore (20) can be optionally connected to a vent groove (24) between the housing section (12) and the vent body (18) by rotating the vent body (18) about the rotation axis (16) in order to open the vent valve (10), characterized in that the vent groove (24) is provided in the sealing element (22), which is designed as an annular body with an inner circumferential surface (72), an outer peripheral surface (74) and an end face (76) facing away from the vent body (18), wherein the vent groove (24) extends from the end face (76) to the inner peripheral surface (72) of the sealing element (22) and forms a sealing edge (26) which runs parallel to the axis of rotation (16). Vent valve (10) after claim 1 , characterized in that the sealing element (22) has at least one circumferential sealing bead (86, 88, 90, 92) on the inner peripheral surface (72) and/or the outer peripheral surface (74). Vent valve (10) after claim 2 , characterized in that the sealing element (22) has two circumferential sealing beads (86, 88) on the inner peripheral surface (72), which are spaced apart from one another along the axis of rotation (16). Vent valve (10) after claim 3 , characterized in that one of the sealing beads (86, 88) on the inner peripheral surface (72) of the sealing element (22) is arranged at a point (76) of the sealing element (22) is formed. Vent valve (10) according to one of the Claims 2 until 4 , characterized in that the sealing element (22) has two circumferential sealing beads (90, 92) on the outer peripheral surface (74), which are spaced apart from one another along the axis of rotation (16). Vent valve (10) according to one of the Claims 2 until 5 , characterized in that a sealing bead (92) is provided on the outer peripheral surface (74) of the sealing element (22) near the end face (76) of the sealing element (22) and serves to press the sealing element (22) against a bottom portion (71) of the vent body (18). Vent valve (10) according to one of the Claims 2 until 6 , characterized in that a sealing bead (88) on the inner peripheral surface (72) of the sealing element (22) and a sealing bead (90) on the outer peripheral surface (74) of the sealing element (22) are arranged in an imaginary common plane which runs transversely to the axis of rotation (16) in a rotationally symmetrical region of the sealing element (22) outside the venting groove (24). Vent valve (10) according to one of the preceding claims, characterized in that the sealing element (22) is fixed in a form-fitting manner in the housing section (12). Vent valve (10) after claim 8 , characterized in that the sealing element (22) for the rotational angle orientation in the housing section (12) has an orientation extension (78) which deviates from the rotational shape and which is received in a complementary recess (80) of the housing section (12). Vent valve (10) according to one of the preceding claims, characterized in that the vent groove (24) has a semicircular cross-section. Vent valve (10) according to one of the preceding claims, characterized in that the vent bore (20) of the vent body (18) has a blind bore section (64) running along the axis of rotation (16) which intersects a blind bore section (66) of the vent bore (20) running transversely to the axis of rotation (16). Vent valve (10) according to one of the preceding claims, characterized by a securing element (28) which holds the vent body (18) axially fixed in the receiving bore (14) of the housing section (12), but nevertheless allows rotation of the vent body (18) in the receiving bore (14). Vent valve (10) according to one of the preceding claims, characterized in that the vent body (18) has a nose-shaped portion (48) which can be brought into contact with a stop surface (44) provided on the housing portion (12) when a closed position of the vent valve (10) is reached. Vent valve (10) according to one of the preceding claims, characterized by a locking device (54) provided between the vent body (18) and the housing section (12), which serves to lock the vent body (18) in the closed position of the vent valve (10) relative to the housing section (12).

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