Classifications

• • 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
  • F16J1/00—Pistons; Trunk pistons; Plungers
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
  • F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
• • 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
  • F16J1/00—Pistons; Trunk pistons; Plungers
  • F16J1/005—Pistons; Trunk pistons; Plungers obtained by assembling several pieces
  • F16J1/006—Pistons; Trunk pistons; Plungers obtained by assembling several pieces of different materials
  • F16J1/008—Pistons; Trunk pistons; Plungers obtained by assembling several pieces of different materials with sealing lips
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/005—Components of axially engaging brakes not otherwise provided for
  • F16D65/0068—Brake calipers
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/14—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position
  • F16D65/16—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake
  • F16D65/18—Actuating mechanisms for brakes; Means for initiating operation at a predetermined position arranged in or on the brake adapted for drawing members together, e.g. for disc brakes
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D65/00—Parts or details
  • F16D65/78—Features relating to cooling
  • F16D2065/785—Heat insulation or reflection
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2121/00—Type of actuator operation force
  • F16D2121/02—Fluid pressure
  • F16D2121/04—Fluid pressure acting on a piston-type actuator, e.g. for liquid pressure
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2125/00—Components of actuators
  • F16D2125/02—Fluid-pressure mechanisms
  • F16D2125/06—Pistons
• • 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
  • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
  • F16D2200/00—Materials; Production methods therefor
  • F16D2200/0004—Materials; Production methods therefor metallic
  • F16D2200/0026—Non-ferro
  • F16D2200/003—Light metals, e.g. aluminium

Definitions

• the present invention pertains to brake pistons and piston noses, e.g. , for use in automotive disc brake systems.
• Pistons can be made from many materials, such as steel, aluminum, stainless steel, titanium or engineered compounds such as phenolics and ceramics.
• the material used for the piston is the same as the material used for the caliper body, so that changes in dimensions caused by thermal expansion wi ll affect the piston the same as the body of the caliper and, in particular, so that critical dimensions will change approximately together. Doing so maintains the relationships or tolerances between key components like the piston, piston seals, piston groove and piston bore in a narrower range. This maintenance of proper tolerances adds to caliper performance and durability.
• pistons that are used in high- temperature environments e.g. , high-performance braking systems
• more than one material e.g. , a piston body made of aluminum (where an aluminum caliper also is being used) fitted with a nose of stain less steel, titanium or ceramic.
• the present disclosure concerns, among other things, the configurations of such noses to improve their performance.
• FIG. 1 -3 uses a simple design involving a ceramic nose 1 0 attached to an aluminum piston body 12. Generally speaking, this design simply relies on choice of material (ceramic) to reduce the thermal conductivity.
• FIG. 4-6 uses a titanium nose 20 attached to an aluminum piston body 22. However, in addition to using a low-thermal- conductivity material (titanium) for the nose 20, this design also reduces thermal conductivity by shaping the nose 20 so as to reduce contact area between the piston and the brake pad, i. e. , using only an outer ring 24 as the contact surface and drilling holes 25 through the ring 24. In existing implementations of piston nose 20, ring 24 is 5 or 8 millimeters (mm) high and has holes 25 that are 3 or 5 mm in diameter, respectively.
• this thin layer of metallic material exhibits a spring-like characteristic, acting like a compressible spring, and thereby requiring a longer or variable distance to be travelled by the piston before direct force is exerted on the brake pad.
• This delay in piston force being realized on the back of the brake pad unfavorably affects brake system performance by increasing the time required to engage the brakes and the distance the brake pedal has to travel.
• one embodiment of the invention is directed to a brake piston that includes a piston body and a top surface, in which the top surface is wider than the piston body and has a smal l portion that is slightly raised, relative to the rest of the top surface, so that when in use only the small raised portion makes contact with a backing plate of a brake pad.
• FIG. 12 Another embodiment is directed to a disc brake caliper assembly that includes a caliper body having a receiving cavity and a piston inserted into the receiving cavity of the caliper body.
• the piston in turn, inc ludes: (a) a piston body; and (b) a top surface that is wider than the piston body and that has a small portion that is slightly raised, relative to the rest of the top surface, so that when in use only the small raised portion makes contact with a backing plate of a brake pad.
• a still further embodiment is directed to a piston nose having a bottom side configured to attach to a top side of a piston and a top side that is substantially wider than the bottom side and that includes a top surface that has a small portion that is slightly raised relative to the rest of the top surface.
• Figure 1 is a perspective view of a first conventional piston.
• Figure 2 is a cutaway view of the first conventional piston.
• Figure 3 is a sectional view of the first conventional piston.
• Figure 4 is a perspective view of a second conventional piston.
• Figure 5 is a cutaway view of the second conventional piston.
• Figure 6 is a sectional view of the second conventional piston.
• Figure 7 is a sectional view of a piston according to a first representative embodiment of the present invention.
• Figure 8 is an exploded sectional view of a caliper assembly and brake pad according to the first representative embodiment of the present invention.
• Figure 9 is a perspective view of a piston according to a second
• Figure 1 0 is a cutaway view of the piston according to the second representative embodiment.
• Figure 1 1 is a sectional view of the piston according to the second representative embodiment.
• Figure 1 2 is an exploded cutaway view of a caliper assembly and brake pad according to the second representative embodiment of the present invention
• Figure 1 3 is an exploded sectional view of a caliper assembly and brake pad according to the second representative embodiment of the present invention.
• Figure 1 4 is a perspective view of three adjacent pistons, used in a single cal iper assembly, according to a third representative embodiment of the present invention.
• a piston nose according to the preferred embodiments of the present invention includes a wider top portion as compared to conventional noses.
• the basic configuration of a piston body 80 with attached nose 1 00 (together forming the entire piston 1 05) is illustrated in Figure 7.
• the piston body 80 is made of aluminum and the nose 1 00 is made of titanium (for the purpose of reducing thermal conduction).
• other materials instead may be used, e.g. , other materials having low thermal conductance for piston nose 1 00.
• top portion 1 1 0 of nose 1 00 is wider than the piston body 80, resulting in additional shielding of thermal radiation.
• top portion 1 1 0 is as wide as possible, given other practical considerations, in order to provide the maximum amount of shielding.
• top portion 1 1 0 extends a distance 1 1 2 of at least 1 -2 mm (millimeters) beyond the outer edge of piston body 80 and, in some embodiments, at least 4-6 mm beyond the outer edge of piston body 80. In other embodiments, it extends an average of at least 1 -2 mm (millimeters), or an average of at least 4-6 mm, beyond the outer edge of piston body 80.
• a relatively small portion 1 1 3 of the top surface 1 14 of nose 1 00 is slightly raised, relative to the rest 1 1 5 of top surface 1 1 4, so that only that raised portion 1 1 3 makes contact with the backing plate of the brake pad.
• the main advantage of this structure is that a heat shield (the wider top surface 1 14) is provided while minim izing the surface area that is required to contact the backing plate of the brake pad (thereby minimizing the direct thermal conductance to the piston).
• An additional benefit is that the resulting air pockets and regions of air circulation between the brake pad and the lower portions 1 1 5 of the top surface 1 14 further reduce thermal conductivity.
• the raised portion 1 1 3 consists of a ring of uniformly sized and uniformly angularly spaced elevated (or raised) areas, separated by uniformly sized and uniformly angularly spaced gaps.
• nose 1 00 is manufactured as a separate component by cutting a disc of titanium, e.g. , using a lathe and/or a cross-cutter, to produce the desired configuration. More preferably, raised portions 1 1 3 are formed by cutting away metal (e.g. , above lower portions 1 1 5) so as to leave raised portions 1 13. Once finished, nose 1 00 can be used to produce a complete brake caliper assembly in the manner shown in Figure 8.
• nose 100 is installed onto piston body 80, which is then inserted into a receiving cavity 1 35 within the caliper body 137 (after installing a high-pressure seal 1 38 into a corresponding circular groove 139 and an optional dust boot into optional dust boot groove 1 40, also within the hydraulic piston cavity 1 35).
• piston nose 1 00 is positioned so as to abut the backing plate 1 42 of the brake pad 143.
• pressurized hydraulic brake fluid in the cavity 1 35 (connected to a fluid reservoir by a line not shown in the drawings) forces the piston 105 against the brake pad 143 which, in turn, presses against a brake disc (not shown), slowing down its rotational motion through friction (which produces the above-referenced heat buildup).
• Figures 9- 1 1 illustrate a piston body 1 80 and attached nose 200 according to a more-specific embodiment of the present invention.
• Figures 9 and 1 0 more clearly illustrate a ring of raised areas 213 separated by gaps 21 5, as mentioned above. In the present embod iment, there are eight such raised areas 2 13 separated by eight such gaps 21 5. However, any other number instead may be used.
• the outer edge of this ring preferably at least approximately corresponds to the outer edge of piston body 1 80, and the inner image of the ring at least approximately corresponds to the inner surface of piston body 1 80 (which defines the hollow core 224).
• raised areas 21 3 are higher than the rest of the top surface 21 4 of nose 200, thereby resulting in a layer of air above such rest of the top surface 214 and facil itating movement of such air.
• raised areas 2 1 3 are approximately 1 mm higher than the rest of the top surface 2 14. Even greater elevation distances can provide even further reduce thermal conductance; however, doing so also increases the overal l length of the resulting piston and, because space is at a premium in high performance vehicles, it generally is desirable to keep the overall caliper assembly as small as possible.
• a secondary surface 223 also can be provided at a lower level than (indented from) the top surface 2 14 (e.g., above core 224), thereby providing even greater thermal isolation within that region.
• nose 200 is securely attached to piston body 1 80 through the use of a snap ring 2 1 7, and the piston body 1 80 includes a groove 21 8 for seating a dust boot 222.
• nose 200 can be attached to piston body 1 80 in any of a variety of other ways.
• groove 21 8 and the corresponding dust boot 222 can be omitted.
• piston body 1 80 has a hol low core 224
• Piston nose 200 includes a fairly shallow ridge 226 (circular in the present embodiment) for fitting over the top (or distal) end of piston body 1 80 and a central portion 227 that extends somewhat into the core 224 of the piston body 1 80.
• piston nose 200 in alternate embod iments other means are employed for attaching piston nose 200 to piston body 1 80.
• ridge 226 instead can be made to have a smaller diameter so that it fits within the inner wall of hollow core 224.
• FIG. 1 2 and 1 3 i llustrate a brake pad 230 and the components of the foregoing caliper assembly in an exploded fashion.
• the wider top portion 220 of nose 200 preferably is at least as wide as the dust boot 222, thereby protecting it from thermal radiation. More preferably, this margin is as large as practically possible, e.g. , at least 1 -2 mm at each position around the circumference or an average of at least 1 -2 mm around the c ircumference.
• caliper components 235 and 237-240 correspond to components 1 35 and 1 37- 1 40 (discussed above), respectively.
• the top portion e.g.
• the nose configuration described above preferably is modified, e.g. , as shown in Figure 1 4, to maximize the aggregate shielding effect.
• the top portions 280 of noses 300 are straight (or at least approximately straight along the sides 282 where they are adjacent to each other, but are otherwise round (or at least rounded).
• the gaps between adjacent noses 300 (along the sides 282) preferably are approximately 0.05-0. 1 mm wide.
• the nominal thickness of the top portion 1 1 0 or 220 of the nose according to the preferred embodiments is approximately 0.5- 1 .0 mm and, as noted above, the raised sections 1 1 3 or 2 1 3 preferably extend an additional 1 mm above that.
• the total additional length provided by a piston nose according to the preferred embodiments can be approximately 2 mm, or even less. This is substantial ly less than the additional length provided by a conventional nose (such as the piston nose 20 illustrated in Figures 4-6) which, as noted above, can be 5 or 8 mm.
• a piston nose according to the present invention generally can significantly reduce the amount of heat that is transferred to the piston from the brake pad.
• a piston nose according to the present invention typically is much faster and easier to manufacture than a conventional piston nose.
• a piston nose according to the present invention does not require any drilling of holes and often requires significantly less lathing.
• a brake piston according to the present invention can be uti lized in an automotive braking system and is particularly useful in high-performance braking systems. In addition, it can be used in other high-performance applications, such as for slowing a hel icopter rotor.
• functionality sometimes is ascribed to a particular module or component. However, functionality general ly may be redistributed as desired among any different modules or components, in some cases completely obviating the need for a particular component or module and/or requiring the addition of new components or modules.
• the precise distribution of functionality preferably is made according to known engineering tradeoffs, with reference to the specific embodiment of the invention, as will be understood by those skilled in the art.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Braking Arrangements (AREA)
• Snaps, Bayonet Connections, Set Pins, And Snap Rings (AREA)
• Mutual Connection Of Rods And Tubes (AREA)
• Pistons, Piston Rings, And Cylinders (AREA)

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Applications Claiming Priority (2)

Publications (1)

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Citations (4)

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• 2012
  • 2012-01-13 KR KR1020137021340A patent/KR101914253B1/ko not_active Expired - Fee Related
  • 2012-01-13 CN CN201280005419.5A patent/CN103339402B/zh not_active Expired - Fee Related
  • 2012-01-13 JP JP2013549554A patent/JP6163107B2/ja not_active Expired - Fee Related
  • 2012-01-13 KR KR1020187031131A patent/KR20180120790A/ko not_active Ceased
  • 2012-01-13 WO PCT/US2012/021164 patent/WO2012097203A1/en not_active Ceased
  • 2012-01-13 EP EP12734297.0A patent/EP2663785A4/en not_active Withdrawn
  • 2012-01-13 CA CA2824790A patent/CA2824790C/en not_active Expired - Fee Related
  • 2012-01-13 AU AU2012205429A patent/AU2012205429B2/en not_active Ceased
  • 2012-01-13 US US13/349,671 patent/US8776956B2/en active Active
  • 2012-01-13 CN CN201610880644.3A patent/CN107420467A/zh active Pending
• 2014
  • 2014-06-11 US US14/301,971 patent/US10174840B2/en active Active
• 2017
  • 2017-01-06 AU AU2017200090A patent/AU2017200090A1/en not_active Abandoned
  • 2017-06-16 JP JP2017118756A patent/JP2017198342A/ja active Pending
• 2018
  • 2018-05-10 HK HK18106082.6A patent/HK1246843A1/zh unknown

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