Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
  • B60T15/00—Construction arrangement, or operation of valves incorporated in power brake systems and not covered by groups B60T11/00 or B60T13/00
  • B60T15/02—Application and release valves
  • B60T15/04—Driver's valves
  • B60T15/043—Driver's valves controlling service pressure brakes
  • B60T15/045—Driver's valves controlling service pressure brakes in multiple circuit systems, e.g. dual circuit systems
  • B60T15/046—Driver's valves controlling service pressure brakes in multiple circuit systems, e.g. dual circuit systems with valves mounted in tandem

Definitions

• the invention relates to a pneumatic control valve, in particular a dual-circuit brake transducer in a compressed-air brake system of a vehicle for correcting a brake pressure which corresponds to a desired braking action, having at least one first valve system which is arranged in a housing upper part with a first valve piston which can be actuated via an elastomer spring element manually or by means of an actuator and with a first annular plate valve which interacts therewith, and having a second valve system which is arranged in a housing lower part with a coaxially arranged second valve piston which can be actuated pneumatically and/or mechanically by the first valve system and with a second annular plate valve which interacts therewith.
• a control valve of this type corresponds in terms of its construction to the known control valves of Wabco Series No. 461315xx which is shown in Fig. 1 in a longitudinal section.
• the first valve piston is guided in a housing upper part and is sealed by means of an O-ring seal.
• a plunger piston which can be actuated manually or with the aid of an actuator acts via a pressure plate and an elastomer spring element on the first valve piston which for its part interacts in a known way with a first valve system, to which it belongs.
• a push rod acts on the plunger piston with an angular deviation which changes upon actuation with regard to the longitudinal axis of the control valve, lateral forces and tilting moments are transmitted via the pressure plate on the valve piston.
• the first valve piston is guided in the housing upper part by way of a cylindrical guide sleeve which has a comparatively large axial length, as a result of which the installation space which is required for it in the housing upper part is rather long.
• the invention is based on the object of improving a pneumatic control valve of the type mentioned at the outset, in such a way that the sealing action of the valve piston with respect to the housing upper part is impaired less by tilting moments and transverse forces which occur upon actuation of the control valve.
• the novel control valve is to be comparatively simple to assemble and to have a comparatively low weight.
• Claims 9 and 10 relate to a vehicle which is equipped with the novel control valve and to the use of the novel control valve in a compressed-air brake system of a vehicle.
• a pneumatic control valve in particular a dual-circuit brake transducer in a compressed-air brake system of a vehicle for correcting a brake pressure which corresponds to a desired braking action, having at least one first valve system which is arranged in a housing upper part with a first valve piston which can be actuated via an elastomer spring element manually or by means of an actuator and with a first annular plate valve which interacts therewith, and having a second valve system which is arranged in a housing lower part with a coaxially arranged second valve piston which can be actuated pneumatically and/or mechanically by the first valve system and with a second annular plate valve which interacts therewith.
• the elastomer spring element and the first valve piston are configured in one piece as a composite component, and that, in the region of a radial sealing lip of the elastomer spring element, the material of the elastomer spring element engages radially and axially in a positively locking manner around a radially outer section of the first valve piston.
• the depicted single-piece design of elastomer spring element and first valve piston makes a very short overall length of the first valve piston possible.
• the first valve piston has an undercut annular groove, into which a complementarily shaped, annular protrusion on the elastomer spring element engages in a positively locking manner.
• That region of the elastomer spring element which brings about a resilient support of the first valve piston on the pressure plate has a greater Shore hardness than the sealing lip.
• the elastomer spring element is of frustoconical configuration outside its connecting region to the first valve piston, and that the elastomer spring element is supported in said frustoconical region with its smaller diameter region on the first valve piston and with its larger diameter region on the pressure plate.
• the first valve piston has, radially on the inside, a hollow-cylindrical projection, into which a section of the plunger piston protrudes in a positively locking manner, which section centres the first valve piston radially. Accordingly, an axial actuating force can be exerted on the first valve piston by means of the plunger piston via the pressure plate and the elastomer spring element and, moreover, the plunger piston ensures that the first valve piston is arranged in a radially centrally centred manner in the upper housing part of the control valve even during a valve actuation. This is very advantageous because this centring task cannot be fulfilled by the sealing lip which is arranged radially on the outside of the component part, consisting of the elastomer spring element and the first valve piston.
• the hollow-cylindrical projection of the first valve piston has a central hole, through which a cylindrical projection of the plunger piston protrudes.
• the cylindrical projection of the plunger piston serves for the actual centring of the plunger piston, which will still be discussed in conjunction with an exemplary embodiment.
• the plunger piston is received fixedly in a central, stepped bore of the pressure plate, that the plunger piston is guided axially in the housing upper part by means of a radially outer hollow-cylindrical projection of the pressure plate, and that the elastomer spring element is supported axially and radially with its larger diameter region which is remote from the piston radially inside the hollow-cylindrical projection of the pressure plate on the said pressure plate.
• the plunger piston is also radially centred satisfactorily at its upper end.
• an actuating force of the plunger piston can be forwarded very effectively to the first valve piston via the pressure plate and the elastomer spring element.
• the elastomer spring element can be moulded integrally onto the valve piston in a mould which receives the valve piston, it being possible for those surface regions of the valve piston which come into contact with the elastomer spring element during moulding to be coated with an adhesion promoter.
• the elastomer spring element With regard to the preferred embodiment of the elastomer spring element with a region with a greater Shore hardness which brings about the resilient support of the valve piston on the pressure plate and with a sealing lip with a smaller Shore hardness, the elastomer spring element can be moulded onto the valve piston by way of a two-component injection-moulding method.
• the abovementioned object is achieved by a vehicle, for example by a commercial vehicle, which is characterized by a control valve of the type defined in the preceding text. Furthermore, the object is also achieved by the use of the control valve according to the invention in a compressed-air brake system of a vehicle.
• Fig. 1 shows a diagrammatic longitudinal section illustration of a control valve according to the prior art mentioned at the outset
• Fig. 2 shows a diagrammatic longitudinal section illustration of the control valve having the features of the invention.
• control valve 45 shown in Fig. 1
• FIG. 1 the control valve 45 (shown in Fig. 1) according to the prior art will be described only with regard to features which are in accordance with the control valve according to the invention.
• the control valve 45 has a housing upper part 46 and a housing lower part 47 which are joined together in a sealed manner.
• a plunger piston 48 which can be actuated manually or by means of an actuator is arranged axially displaceabiy in the housing upper part 46, which plunger piston 48 acts via a pressure plate 49 and a frustoconical elastomer spring element 52 on a first valve piston 53.
• the said first valve piston 53 is guided with its cylindrical shell in a sealed manner on a cylindrical inner wall of the housing upper part 46 and is secured against sliding out by a securing ring 51 which is arranged in a groove 50 of the housing upper part 46.
• the first valve piston 53 interacts with a first annular plate valve 54.
• a second valve piston 55 is arranged displaceabiy in the housing upper part 46 coaxially with respect to the first valve piston 53 and interacts with a second annular plate valve 56.
• the elastomer spring element 52 bears with its small diameter region 52c against the pressure plate 49 and with its large diameter region 52d against the first valve piston 53.
• the control valve 1 (according to Fig. 2) which is configured according to the invention has a housing consisting of a housing upper part 2 and a housing lower part 3 which are joined together in a sealed manner with a sealing ring 29 positioned in between.
• a plunger piston 4 penetrates a pressure plate 5 centrally and is guided axially displaceably in the housing upper part 2 via its radially outer hollow-cylindrical projection 5a, and is secured against falling out of the housing upper part 2 by a securing ring 7 which is arranged in a circumferential groove 6 of the housing upper part 2.
• the housing upper part 2 is sealed to the outside by means of a folding bellows 8.
• An elastomer spring element 9 of frustoconical configuration is arranged between the pressure plate 5 and a first valve piston 10.
• the elastomer spring element 9 is moulded integrally on the first valve piston 10 outside its frustoconical region and engages around the material of the elastomer spring element 9 and engages over the first valve piston 10 there.
• a radially outwardly directed sealing lip 9a is formed on the composite component consisting of elastomer spring element 9 and first valve piston 10.
• the first valve piston 10 is provided with an undercut annular groove 10a on its side which faces the pressure plate 5, into which annular groove 10a an annular axial protrusion 9b of the elastomer spring element 9 engages.
• the elastomer spring element 9 is preferably moulded onto the valve piston 10 in a mould which receives the first valve piston 10.
• those surface regions of the first valve piston 10 which come into contact with the elastomer spring element 9 during moulding are coated with an adhesion promoter.
• the frustoconical region of the elastomer spring element 9 is preferably composed of an elastomer with a greater Shore hardness than that region, on which the sealing lip 9a is formed, it being possible for the elastomer spring element 9 to be moulded
• the first valve piston 10 has a hollow-cylindrical projection 12 which ends in an annular sealing seat 13.
• a first axial cylindrical projection 4a of the plunger piston 4 is guided through a hole 57 in a radial, head-shaped protrusion 11 on the first valve piston 10.
• a securing ring 19 which is arranged in a groove of the first cylindrical projection 4a holds the arrangement comprising the plunger piston 4, the pressure plate 5, the elastomer spring element 9 and the first valve piston 0 together as a structural unit which can be pre-assembled, with a predefined prestress which is applied by the
• the first valve piston 10 interacts in a known manner by way of its annular sealing seat 13 on its cylindrical projection 12 with a first annular plate valve 14.
• the first annular plate valve 14 has a radial sealing face 15 which for its part interacts in a known manner with a first non-displaceable sealing seat 16 in the housing upper part 2.
• the first annular plate valve 14 is guided with a cylindrical projection 14a radially inside a second valve piston 30, such that it can be displaced axially over a small travel, and is sealed with respect to the second valve piston 30 by means of a sealing ring 31.
• the first annular plate valve 14 is surrounded by a first pressure space 17 which is fed compressed air from a compressed-air source in a manner which is known but not shown.
• the first annular plate valve 14 is pierced, as a result of which a venting passage is formed.
• a back-pressure spring 20 is supported on the housing upper part 2 and on the first valve piston 10 and ensures that the arrangement of the plunger piston 4, the pressure plate 5, the elastomer spring element 9 and the first valve piston 10 bears axially against the upper securing ring 7 when the plunger piston 4 is not actuated.
• a compression spring 21 which is arranged in the first pressure space 17 is supported axially at one end on the first annular plate valve 14 and at the other end on a lip seal 24 which is arranged in the housing upper part 2 and is secured against falling out by a securing ring 25.
• a brake pressure space 22 for a first brake circuit (not shown) is formed between the first valve piston 10 and the first non-displaceable sealing seat 16, in which brake pressure space 22 a modulated brake pressure is built up by the interaction of the plunger piston 4 with the first valve piston 10 and the first annular plate valve 14.
• a supporting element 23 is arranged axially displaceably on the first cylindrical projection 4a of the plunger piston 4 and bears against the head-shaped radial protrusion 1 1 of the first valve piston 10 under the pressure of a compression spring 26.
• the said compression spring 26 is supported with its other end on a supporting disc 27 which bears against a step between the first cylindrical projection 4a and a second cylindrical projection 4b of smaller diameter of the plunger piston 4.
• the supporting disc 27 is fixed on the said step by means of a securing ring 28.
• the supporting disc 27 comprises a number of perforations 27a or perforated holes to facilitate exhaust air flow during brake release.
• the second valve piston 30 is guided axially in the housing lower part 3 such that it is sealed via two O-sealing rings 32, 33, and interacts by way of an annular sealing seat 34 with a second annular plate valve 37.
• a radial sealing face 38 of the second annular plate valve 37 interacts in a known way both with the annular sealing seat 34 on the second valve piston 30 and with a second, non-displaceable sealing seat 35 on a hollow-cylindrical projection 36 in the housing lower part 3.
• the hollow- cylindrical projection 36 in the housing lower part 3 is surrounded by an annular brake pressure space 39 which is connected to a second brake circuit (not shown), in order to feed a modulated brake pressure to the said second brake circuit.
• a second pressure space 17a which is fed compressed air from a
• compressed-air source in a manner which is not shown is formed between a hollow- cylindrical projection 37a of the second annular plate valve 37 and the hollow- cylindrical projection 36 in the housing lower part 3.
• the said second pressure space 17a can be flow-connected in a manner which is not shown to the first pressure space 17 in the region of the first annular plate valve 14.
• a compression spring 40 is arranged in the second pressure space 1 a, which compression spring 40 is supported at one end on the second annular plate valve 37 and at the other end on a lip seal 41 which for its part is secured by a supporting ring 42.
• the supporting ring 42 is secured against falling out by a securing ring 43 and is connected via radially inwardly protruding radial spokes 42a to a hollow-cylindrical guide 42b which serves to guide the second cylindrical projection 4b of the plunger piston 4, with the result that the said plunger piston 4 is guided over a great length firstly via the pressure plate 5 in the housing upper part 2 and via the hollow- cylindrical guide 42b in the housing lower part 3.
• the control valve 1 is ventilated in a known way by the venting passage and a venting cap 44 on the housing lower part 3 when the brake pressure in the brake pressure spaces 22 and 39 is reduced or neutralized completely by retraction of the plunger piston 4.
• the control valve 1 which is configured according to the invention is of very compact overall design because the first valve piston 53 according to Fig. 1 and the first valve piston 10 according to Fig. 2 have approximately the same diameter. With regard to its seal by way of the sealing lip 9a which is arranged radially on the outside, however, the first valve piston 10 of the control valve 1 according to Fig. 2 is unsusceptible to tilting moments and transverse forces which are applied by the plunger piston 4. As a result of the single-piece configuration of elastomer spring element 9 and first valve piston 10, they can be mounted easily during the assembly of the control valve 1 and the production of the sealing lip 9a which is arranged radially on the outside on the first valve piston 10 can be carried out comparatively simply. In addition, the first, usually metallic valve piston 10 is very short axially, as a result of which the overall weight of the control valve 1 can be lower than in the case of known control valves of the same design.
• the first valve piston 10 moves down and opens First annular plate valve 14, resulting in a connection of the air supply to the delivery port.
• the Supporting element 23 is already in contact with the First valve piston 10, delivery air from top circuit just moves down to the Second valve piston 30 and opens Second annular plate valve 37 without any additional pressure build up in top circuit.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transportation (AREA)
• Valves And Accessory Devices For Braking Systems (AREA)
• General Engineering & Computer Science (AREA)

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• 2014
  • 2014-10-20 IN IN5978CH2013 patent/IN2013CH05978A/en unknown
  • 2014-10-20 WO PCT/IB2014/002175 patent/WO2015092500A1/en active Application Filing
  • 2014-10-20 US US15/106,402 patent/US9963136B2/en active Active

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