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WO2004078546A1 - Valve pneumatique presentant une caracteristique de commande de flux de sortie amelioree - Google Patents

Valve pneumatique presentant une caracteristique de commande de flux de sortie amelioree Download PDF

Info

Publication number
WO2004078546A1
WO2004078546A1 PCT/US2003/038773 US0338773W WO2004078546A1 WO 2004078546 A1 WO2004078546 A1 WO 2004078546A1 US 0338773 W US0338773 W US 0338773W WO 2004078546 A1 WO2004078546 A1 WO 2004078546A1
Authority
WO
WIPO (PCT)
Prior art keywords
cavity
delivery
flow
pneumatic fluid
air
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/US2003/038773
Other languages
English (en)
Inventor
Thanh Ho
Robert J. Herbst
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bendix Commercial Vehicle Systems LLC
Original Assignee
Bendix Commercial Vehicle Systems LLC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/379,956 external-priority patent/US20040107990A1/en
Application filed by Bendix Commercial Vehicle Systems LLC filed Critical Bendix Commercial Vehicle Systems LLC
Priority to CA2508745A priority Critical patent/CA2508745C/fr
Priority to AU2003298001A priority patent/AU2003298001B2/en
Priority to MXPA05005940A priority patent/MXPA05005940A/es
Publication of WO2004078546A1 publication Critical patent/WO2004078546A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

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

Definitions

  • the present invention relates to a valve for quick release of pneumatic pressure in a pneumatic fluid system. It finds particular application with air brakes used in conjunction with heavy or commercial vehicles and will be described with particular reference thereto. The invention may be used in other applications without departing from the spirit and scope of the invention.
  • the actuator 3 for the brake valve When the actuator 3 for the brake valve is released (e.g., foot lifted from a brake pedal), the air flows from the brake chamber 4 to the actuator 3 through a fixed inlet orifice 1. While the fixed inlet orifice does provide some pressure differential across the exhaust diaphragm, relatively little air, less than 50%, actually is exhausted through the exhaust port, and only slight improvements are realized for the release timing. Moreover, this method restricts the inlet capacity of the valve. Furthermore, this method does not sufficiently improve the release timing to meet the FMVSS 121 requirements.
  • Patent disclosure DE3938101A1 discusses reducing the vent time of a pressure control valve for improved release timing.
  • a "reflux" valve is placed directly in the inlet flow path, thus restricting the inlet flow.
  • Inclusion of a reflux valve that restricts inlet flow doesn't, however, provide both apply and release timing sufficient to meet, for example the requirements of FMVSS 121.
  • Apply timing relates to how quickly the brakes are applied after pressing the brake pedal.
  • the enhancement for the release timing in disclosure DE3938101A1 degrades the performance of the valve for the apply timing. With the current sizing requirements of the antilock brake system (ABS) valve, it is not capable to meet both apply and release timing of FMVSS 121 using the "reflux" valve design.
  • ABS antilock brake system
  • the present invention provides a new and improved apparatus and method which addresses the above-referenced problems.
  • FIGURE 1 illustrates a prior art valve
  • FIGURE 2 illustrates a flow diverter as positioned during a brake application in accordance with one embodiment of the present invention.
  • FIGURE 3 illustrates a flow diverter as positioned during a brake release in accordance with one embodiment of the present invention
  • FIGURE 4 illustrates a perspective view of the flow diverter in accordance with one embodiment of the present invention.
  • FIGURE 5 illustrates a graph showing test data.
  • the delivery air of the air brake system valve is diverted to the exhaust port in order to limit the amount of air returning through the inlet port of the valve. In this manner, the release timing is improved without significantly increasing the apply timing.
  • the feature described below meets the required release timing of FMVSS 121 without significantly restricting the inlet capacity of the valve (see Figures 2 and 3) such that the required apply timing of FMVSS 121 is met.
  • the invention is not limited to features requiring compliance with FMVSS 121 release and apply timing requirements, but is discussed below in relation to features that will meet these requirements.
  • applying timing means the time from the first movement of the brake valve actuator (brake pedal) for the brake chamber to reach 60 psi with an initial service reservoir pressure of 100 psi.
  • release timing means the time from initial brake pedal movement (release) for a set of brake chambers initially at 95 psi to reach 5 psi.
  • use of the term “or” herein is the inclusive, and not the exclusive, use. See BRYAN A. GARNER, A DICTIONARY OF MODERN LEGAL USAGE 624 (2d Ed. 1995).
  • the release timing of a brake valve correlates to how quickly the pressure of the pneumatic fluid therein, often air, is released from the brake chamber 4 (see Fig. 1).
  • the present invention provides for a restriction in the fluid flow from the brake chamber 4 to more quickly begin fluid communication with an exhaust port and to redirect more of the fluid to the exhaust port after the actuator 3 is released. This creates a pressure differential across the exhaust diaphragm 2 to unseat the exhaust diaphragm 2 and exhaust fluid.
  • the greater the pressure differential the more quickly the exhaust diapliragm 2 is unseated and the greater is the quantity and speed of the fluid exhausted.
  • the present invention provides a restriction that does not significantly reduce the incoming fluid flow upon application of the actuator 3 to engage the brake. Therefore, there is minimal reduction of the apply timing due to the restriction.
  • the restriction device herein called a flow diverter
  • the flow diverter When in the first position, the flow diverter does not significantly restrict fluid flow to actuate the brake.
  • the flow diverter diverts fluid flow to the exhaust by restricting the flow back in the direction of the actuator 3.
  • the flow diverter may divert all or a portion of the fluid to the exhaust.
  • the flow diverter does not significantly reduce the apply timing, as does a conventional fixed inlet orifice 1.
  • FIGURE 2 illustrates a flow diverter 20 as positioned during a brake application, in accordance with one embodiment of the present invention.
  • FIGURE 3 illustrates the flow diverter 20 as positioned during a brake release operation, in accordance with the embodiment illustrated in FIGURE 2. Air flow paths of the delivery air during brake application and release are shown by arrows in FIGURES 2 and 3, respectively. Flow diverter 20 moves freely within a bore 22 according to relative air pressures in a supply (inlet) cavity 24 and a delivery cavity 26.
  • air from a service reservoir enters the supply (inlet) cavity 24 via an inlet/outlet port 30 when a brake valve 32 is actuated via, for example, a foot pedal 34.
  • the air creates pressure in the supply cavity 24 and passes to a control side 36 of an exhaust diaphragm 40.
  • the pressure created by the air at the control side 36 creates a stronger force on the exhaust diaphragm 40 than the pressure on the other side of the exhaust diaphragm 40 and urges the exhaust diapliragm 40 to seat against a housing wall 42 at a point 44.
  • the exhaust diaphragm 40 will be biased to seat against the housing wall 42 at point 44.
  • a portion of the other side of the exhaust diaphragm 40 is exposed to the pressure of delivery cavity 26 and a portion is exposed to the pressure of an exhaust port 46.
  • the pressure of the exhaust port 46 is generally atmospheric pressure.
  • the seating of the exhaust diaphragm 40 at the point 44 creates a seal between the delivery cavity 26 and the exhaust port 46.
  • the air creating pressure in the supply cavity 24 also passes through a passage 48 between a supply (hold) diaphragm 50 and a housing wall 52. [0020] After passing through the passage 48, the air passes into the bore 22.
  • a flow diverter 20, which is described in more detail below, is positioned within the bore 22.
  • the flow diverter 20 includes a restrictor portion 100 and a spacer portion 102.
  • the restrictor portion 100 is flat; furthermore, the spacer portion includes a plurality (e.g., four) of legs 102a, 102b, 102c, 102d.
  • an outer diameter of the restrictor portion 100 is sized to be smaller than an inner diameter of the bore 22.
  • the outer diameter of the restrictor portion 100 is about 0.475 inches while the inner diameter of the bore 22 is about 0.490 inches.
  • the flow diverter 20 illustrated in FIGURES 2 and 4 represents only one embodiment and other embodiments including other designs, shapes, and/or dimensions of the flow diverter 20 relative to the bore 22 are contemplated.
  • the surface of restrictor portion 100 may be of any shape suitable for use, including regular or irregular polygons, such as rectangular, pentagonal, hexagonal, octagonal, or dodecahedral polygons.
  • the restrictor portion 100 is circular, if the cross-section of the bore 22 is circular.
  • the diameter of the restrictor portion 100 is dimensioned relative to the diameter of the bore 22 such that the restrictor portion 100 provides sufficient resistance to the flow of air to divert a sufficient amount, preferably at least about 50%, of the air in the delivery cavity 26 to the exhaust port 46.
  • the flow diverter 20 also is dimensioned so that there is minimal restriction in the flow of air from supply cavity 24 to delivery cavity 26.
  • the restriction is such that the desired apply timing may still be obtained.
  • the flow diverter 20 provides a restriction in the flow in this direction of no more than about 25%. Therefore, one of skill in the art may determine the optimum diameter of the restrictor portion 100 without undue experimentation.
  • spacer portion 102 is illustrated with four legs 102a,
  • legs 102b, 102c, 102d there may be any number of legs, including three legs, so long as there is sufficient stability to enable the flow diverter 20 to divert the requisite air to the exhaust port 46 without significantly restricting the flow of air from the supply cavity 24 to the delivery cavity 26 when the brake valve 32 is actuated.
  • the number of legs may be chosen without departing from the spirit and scope of the invention.
  • the shape of the legs 102a, 102b, 102c, 102d is illustrated as rectangular prisms, but any suitable shape is contemplated, such as any suitable regular or irregular polygon, and is within the spirit and scope of the invention.
  • the shape of the legs 102a, 102b, 102c, 102d is to be selected such that there is minimal interference with air flow between the supply cavity 24 and the delivery cavity 26, while providing sufficient support for the restrictor portion 100.
  • the shape of the legs 102a, 102b, 102c, 102d may be selected to have tapering or curved portions to reduce the turbulent flow characteristics of the air and to reduce stress points on the flow diverter 20.
  • the legs 102a, 102b, 102c, 102d have a triangular cross section. There may also be ribs between the legs or otherwise provided, for example, to provide additional strength for the legs.
  • the specific dimensions of the restrictor portion 100 and the spacer portion 102 may be selected based on the circumstances and parameters of each particular application without departing from the spirit and scope of the invention. Suitable dimensions may be determined without undue experimentation based on the measurement of the release timing and apply timing of the brake.
  • the flow diverter 20 may be a spherical ball or a cylindrical slug or other shape dimensioned such that, for example, the pressure of the air in the supply cavity 24 is sufficient to move the ball or slug substantially out of the way of the flow of air from the supply cavity 24 to the delivery cavity 26, but the ball or slug interposes restriction in the flow of air from the delivery cavity 26 to the supply cavity 24.
  • the flow diverter 20 need not have both a restrictor portion 100 and a spacer portion 102, but may be provided as one portion.
  • the flow diverter 20 may also completely restrict any flow of air from the supply cavity 24 to the delivery cavity 26. There need not be any leak by or flow of air back into the supply cavity 24 around or through the flow diverter 20.
  • a flapper or check valve may be placed in or near the passage 48 that is in an open position when air is flowing from the supply cavity 24 to the delivery cavity 26, but is in a closed position when air is no longer flowing in that direction.
  • the material from which the flow diverter 20 is made may be any conventional material selected, for example, based on cost, availability, weight, or any other parameter without departing from the spirit and scope of the invention.
  • the material is plastic, but metals, such as aluminum, are also suitable.
  • the specific material chosen may affect the restriction of fluid flow because of, for example, weight or surface smoothness, but the appropriate shape and dimensions for the chosen material may be determined without undue experimentation.
  • the flow diverter 20 is positioned in the bore 22 upon a brake application such that the flow diverter 20 does not substantially interfere with the flow of air from the supply cavity 24 to the delivery cavity 26 via the bore 22.
  • the restrictor portion 100 is above the passage (not shown) from the bore 22 to the delivery cavity 26.
  • the legs 102a, 102b, 102c, 102d are designed such that they do not substantially interfere with the flow of air from the bore 22 to the delivery cavity 26 upon brake application.
  • the flow diverter 20 allows minimally- restricted inlet flow during brake application and meters back flow during brake release.
  • the metering of back flow quickly induces a differential pressure across the exhaust diaphragm triggering the opening of the exhaust seat. This unseating results in the improved release timing that meets the FMVSS 121 timing requirements.
  • the flow diverter 20 is a flow-activated device having two positions of operation. During a brake application the flow diverter is moved by the application air to its minimally restricted open position. This allows the ABS valve to meet the FMVSS 121 apply timing requirement. During the brake application release, the flow of delivered air carries the flow diverter 20 to its metering position (see FIGURE 3). At this position the flow diverter 20 diverts the majority of the air in the delivery cavity to the exhaust port 46 and restricts the amount of air returning to the inlet/outlet 30 of the valve 32 through the clearance between its outside diameter and the housing bore's inside diameter.
  • FIGURE 5 illustrates a graph 200 of test data showing a reduction in the amount of time for releasing pressure in the delivery cavity 26 (see FIGURES 2 and 3) from 95 psi to 5 psi.
  • a line 202 shows that, for these dimensions, it took about 0.564 seconds to release the pressure without the flow diverter according to the present invention.
  • a line 204 shows that, for the same embodiment, it took about 0.267 seconds to release the pressure with the flow diverter according to the present invention.
  • the reduction in flow area for the air passing from the supply cavity 24 to the delivery cavity 26 imposed by the flow diverter 20 for three different tests was about 23.3%, about 23.8%, and about 23.9%, with an average of about 23.7%, or less than 25%.

Landscapes

  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Valves And Accessory Devices For Braking Systems (AREA)
  • Braking Systems And Boosters (AREA)
  • Multiple-Way Valves (AREA)

Abstract

L'invention concerne une valve à utiliser dans un système fluidique pneumatique, notamment un système de freinage aérodynamique. Cette valve permet une libération rapide de fluide pneumatique à partir de la cavité distributrice (26) par le port de sortie (46), lors de l'arrêt du flux provenant du réservoir fluidique pneumatique et traversant la cavité de réserve (24). La valve comprend une soupape distributrice (20) permettant de restreindre l'écoulement du fluide de la cavité distributrice (26) à la cavité de réserve (24), lorsque la pression fluidique pneumatique de la cavité de réserve (34) est inférieure à celle de la cavité distributrice (26) ; et permettant une restriction minimale d'écoulement de la cavité de réserve (24) à la cavité distributrice (26), lorsque la pression dans la cavité de réserve (24) est supérieure à celle de la cavité distributrice (26).
PCT/US2003/038773 2003-03-05 2003-12-05 Valve pneumatique presentant une caracteristique de commande de flux de sortie amelioree Ceased WO2004078546A1 (fr)

Priority Applications (3)

Application Number Priority Date Filing Date Title
CA2508745A CA2508745C (fr) 2003-03-05 2003-12-05 Valve pneumatique presentant une caracteristique de commande de flux de sortie amelioree
AU2003298001A AU2003298001B2 (en) 2003-03-05 2003-12-05 Pneumatic valve with an enhanced exhaust flow control feature
MXPA05005940A MXPA05005940A (es) 2003-03-05 2003-12-05 Valvula neumatica con caracteristicas mejoradas de control del flujo de escape.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US10/379,956 2003-03-05
US10/379,956 US20040107990A1 (en) 2002-12-06 2003-03-05 Enhanced exhaust flow control feature

Publications (1)

Publication Number Publication Date
WO2004078546A1 true WO2004078546A1 (fr) 2004-09-16

Family

ID=32961279

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US2003/038773 Ceased WO2004078546A1 (fr) 2003-03-05 2003-12-05 Valve pneumatique presentant une caracteristique de commande de flux de sortie amelioree

Country Status (4)

Country Link
AU (1) AU2003298001B2 (fr)
CA (1) CA2508745C (fr)
MX (1) MXPA05005940A (fr)
WO (1) WO2004078546A1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015104169A1 (fr) * 2014-01-09 2015-07-16 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Dispositif faisant office de clapet de purge d'air rapide pour actionneurs pneumatiques de systèmes pneumatiques et système pneumatique équipé d'un tel dispositif

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3938101A1 (de) * 1989-11-16 1991-05-23 Bosch Gmbh Robert Regelventileinrichtung
US5118169A (en) * 1987-08-26 1992-06-02 Wabco Westinghouse Fahrzeugbremsen Gmbh Control valve device
DE19744389A1 (de) * 1997-10-08 1999-04-15 Wabco Gmbh Ventileinrichtung

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5918852A (en) * 1996-06-17 1999-07-06 Automatic Switch Company Wide flow range proportional flow valve
US6206487B1 (en) * 1997-09-02 2001-03-27 Akebono Brake Industry Co., Ltd. Brake pressure control device
US6267135B1 (en) * 2000-05-03 2001-07-31 Honeywell Commerical Vehicle Systems Co. ABS modulator with damping foam on exhaust diaphragm

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5118169A (en) * 1987-08-26 1992-06-02 Wabco Westinghouse Fahrzeugbremsen Gmbh Control valve device
DE3938101A1 (de) * 1989-11-16 1991-05-23 Bosch Gmbh Robert Regelventileinrichtung
DE19744389A1 (de) * 1997-10-08 1999-04-15 Wabco Gmbh Ventileinrichtung

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015104169A1 (fr) * 2014-01-09 2015-07-16 Knorr-Bremse Systeme für Nutzfahrzeuge GmbH Dispositif faisant office de clapet de purge d'air rapide pour actionneurs pneumatiques de systèmes pneumatiques et système pneumatique équipé d'un tel dispositif

Also Published As

Publication number Publication date
AU2003298001B2 (en) 2009-07-16
AU2003298001A1 (en) 2004-09-28
CA2508745A1 (fr) 2004-09-16
CA2508745C (fr) 2011-02-08
MXPA05005940A (es) 2005-08-18

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