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
  • B60T15/021—Railway control or brake valves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
• • 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
  • B60T17/00—Component parts, details, or accessories of power brake systems not covered by groups B60T8/00, B60T13/00 or B60T15/00, or presenting other characteristic features
  • B60T17/18—Safety devices; Monitoring
  • B60T17/22—Devices for monitoring or checking brake systems; Signal devices
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J10/00—Engine or like cylinders; Features of hollow, e.g. cylindrical, bodies in general
  • F16J10/02—Cylinders designed to receive moving pistons or plungers
  • F16J10/04—Running faces; Liners
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/32—Sealings between relatively-moving surfaces with elastic sealings, e.g. O-rings
  • F16J15/324—Arrangements for lubrication or cooling of the sealing itself
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16J—PISTONS; CYLINDERS; SEALINGS
  • F16J15/00—Sealings
  • F16J15/16—Sealings between relatively-moving surfaces
  • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S251/00—Valves and valve actuation
  • Y10S251/90—Valves with o-rings

Definitions

• the invention relates to a piston valve unit for a braking system and in particular, but not exclusively, a seal arrangement for a piston valve unit.
• Diaphragm valves Conventional brake systems for railway cars are pneumatically driven and generally use diaphragm valves to control the application and release of pressure to the brake actuators. Considering the normal usage of a railway car, it is expected that the valve will have 44 million open/close cycles between services and a life time of 196 million open/close cycles. Diaphragm valves have been the preferred option historically due to their reliability and robustness, which permits the industry standard servicing intervals and lifetimes to be met.
• the present invention seeks to provide a piston valve unit having a seal arrangement with reduced likelihood of failure between service intervals and a higher operational life for the bore.
• a seal arrangement for a sliding seal which seal arrangement is disposed on a body adapted to move in use, the seal arrangement being adapted to provide a seal between the moving body and a surface of a second body, wherein the second body is formed of a material having substantially aligned inclusions or micro-cracks formed in the surface of the second body, which inclusions or micro-cracks have a longitudinal direction wherein, in use, the direction of motion of the seal arrangement is substantially parallel to the longitudinal direction of the inclusions or micro-cracks.
• the seal arrangement comprises an O ring
• the moving body comprises a piston
• the second body comprises a piston bore.
• the seal has a circular cross-section.
• the second body is formed from an extruded material.
• the second body is formed of extruded anodised aluminium.
• the seal is formed of polyurethane.
• the seal arrangement is provided in a brake valve arrangement for a railway vehicle braking system comprising a piston valve.
• Fig. 1 shows a piston valve unit.
• Fig. 1 shows a piston valve unit for use in a pneumatic railway brake system comprising a main body 1 and a top body 2 disposed on the upper surface of the main body 1 , wherein the main body 1 is provided with a piston bore 3, which piston bore is vented by a farther bore 5.
• the main air supply is provided via an air passage 7 having a choke 8 to a first piston bore 3.
• the air passage 7 then divides with one arm passing to an output stage and the second arm passing to an exhaust passage with a choke 9 at its lower end, which is adapted to vent the valve.
• the piston bore 3 have a stepped structure with the narrower cross section located at the lower part of the bore.
• Each piston bore is provided with a piston 10 having a stepped cross section with the narrower cross section located at the bottom end and the wider cross section located at the upper end.
• Each section is provided with a piston ring 12.
• the operation of each valve is controlled by a respective micro-solenoid 13 which controls the application of a pilot pressure into the respective upper chambers of the valves.
• the pistons toggle between two positions with a stroke of several millimetres.
• the seal 12 is typically a polyurethane O-ring, although other squeeze seal designs are possible, and the body of the valve is made from extruded aluminium.
• the piston bore 3 is anodised.
• the number of sliding operations over which the seals 12 maintain the required performance is dependent on many factors such as material hardness, lubrication, temperature of operation and frictional values of materials.
• the microstructure of the base material surface will typically show many inclusions or micro-cracks. Such inclusions or micro-cracks are generally irregular in shape and so have a longitudinal length which is greater than the lateral width.
• the hard anodised coating is porous and columns of inclusions extend to the surface undermining the near surface material making this friable, which then in use cause craters. As the seal slides across the craters, approximately perpendicular to the inclusion elongation causing the edges of the crater to crack and eventually break away, thus increasing the size of the crater.
• the inclusions are substantially oriented in the direction that the base material is extruded and that when a sliding force is applied along the inclusion, the surface material exhibits different behaviour and the edges of the crater do not crack to the same extent as with an inclusion having a different orientation. Therefore if the grain structure of the base material forming the piston bores is longitudinally aligned with the direction of motion of the seal, the action of the sliding seal causes the seal to bed in rather than abrade. This provides a greatly increased seal life.
• the base material has been described as extruded aluminium, it would be possible to use other materials. It would also be possible to use manufacturing techniques other than extrusion as long as these exhibit substantially aligned micro-cracks and inclusions.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Transportation (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Sealing Devices (AREA)
• Valves And Accessory Devices For Braking Systems (AREA)
• Materials For Medical Uses (AREA)
• Sealing Battery Cases Or Jackets (AREA)
• Glass Compositions (AREA)
• Lift Valve (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=27636827

Family Applications (1)

Country Status (10)

Families Citing this family (4)

Citations (2)

Family Cites Families (19)

• 2003
  • 2003-06-18 GB GB0314183A patent/GB2402980B/en not_active Expired - Lifetime
• 2004
  • 2004-06-16 ES ES04736921T patent/ES2277259T3/es not_active Expired - Lifetime
  • 2004-06-16 JP JP2006516421A patent/JP4829782B2/ja not_active Expired - Lifetime
  • 2004-06-16 DE DE602004003385T patent/DE602004003385T2/de not_active Expired - Lifetime
  • 2004-06-16 EP EP04736921A patent/EP1639281B1/en not_active Expired - Lifetime
  • 2004-06-16 WO PCT/GB2004/002548 patent/WO2004113773A1/en not_active Ceased
  • 2004-06-16 AT AT04736921T patent/ATE346255T1/de not_active IP Right Cessation
  • 2004-06-16 US US10/561,198 patent/US7384022B2/en not_active Expired - Lifetime
  • 2004-06-16 KR KR1020127019273A patent/KR20120098916A/ko not_active Ceased
  • 2004-06-16 KR KR1020057024190A patent/KR20060059903A/ko not_active Ceased
  • 2004-06-16 CN CNB2004800167610A patent/CN100498017C/zh not_active Expired - Lifetime

Patent Citations (2)

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