EP4544202A1 - Brake caliper piston and brake caliper - Google Patents

Brake caliper piston and brake caliper

Info

Publication number
EP4544202A1
EP4544202A1 EP23738877.2A EP23738877A EP4544202A1 EP 4544202 A1 EP4544202 A1 EP 4544202A1 EP 23738877 A EP23738877 A EP 23738877A EP 4544202 A1 EP4544202 A1 EP 4544202A1
Authority
EP
European Patent Office
Prior art keywords
piston
thrust
brake
annular edge
caliper
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.)
Pending
Application number
EP23738877.2A
Other languages
German (de)
French (fr)
Inventor
Alberto Bosis
Mauro BOTTI
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.)
Brembo SpA
Original Assignee
Brembo SpA
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
Application filed by Brembo SpA filed Critical Brembo SpA
Publication of EP4544202A1 publication Critical patent/EP4544202A1/en
Pending legal-status Critical Current

Links

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
    • 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
    • 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
    • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
    • B60T13/74—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive
    • B60T13/741—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with electrical assistance or drive acting on an ultimate actuator
    • 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
    • F16D65/84—Features relating to cooling for disc brakes
    • F16D65/847—Features relating to cooling for disc brakes with open cooling system, e.g. cooled by air
    • 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
    • F16D2121/00—Type of actuator operation force
    • F16D2121/18—Electric or magnetic
    • F16D2121/24—Electric or magnetic using motors
    • 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
    • F16D2125/00—Components of actuators
    • F16D2125/18—Mechanical mechanisms
    • F16D2125/20—Mechanical mechanisms converting rotation to linear movement or vice versa
    • F16D2125/34—Mechanical mechanisms converting rotation to linear movement or vice versa acting in the direction of the axis of rotation
    • F16D2125/40—Screw-and-nut
    • 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
    • F16D2125/18—Mechanical mechanisms
    • F16D2125/44—Mechanical mechanisms transmitting rotation
    • F16D2125/46—Rotating members in mutual engagement

Definitions

  • the present invention relates to a piston for a brake caliper, and to a brake caliper .
  • Brake calipers which comprise at least one piston actuatable by both a brake fluid, to act on a brake pad as a service brake, and a mechanically or electrically actuated thrust member, to act on the brake pad as a parking brake , such as an electromechanical parking brake (EBB) , for example .
  • EBB electromechanical parking brake
  • Such brake calipers comprise a caliper body, in which a hollow cylinder delimited by a cylindrical wall and a bottom wall , substantially transverse to the cylindrical wall , is obtained .
  • the bottom wall internally delimits a through-seat adapted to house in a sealed and rotational manner at least one portion of a rotating member connectable , on one side, to an actuating mechanism, such as an electric motor, and on the other side to the thrust member connectable to the piston .
  • the piston comprises a thrust head adapted to come into contact with the brake pad and a side wall adapted to sealingly slide with respect to the cylindrical wall .
  • the piston delimits an open cavity on the side opposite to the thrust head, adapted to accommodate at least partially the thrust member coupled to the rotating member of the parking brake device .
  • the thrust member is coupled to the rotating member so as to transform the rotation of the rotating member into a translation of the thrust member, which allows a displacement in the axial direction by biasing the brake pad .
  • the brake fluid is fluid- tightly introduced between the bottom wall of the cylinder and the piston, which allows the piston to be actuated by virtue of the fluid pressure, where the rotating member and the thrust member are immersed in the brake fluid and allow the piston to be actuated as a parking brake regardless of the action of the fluid .
  • the disc, the pads , as well as the thrust member and the rotating member are immersed in the braking fluid, they reduce their si ze as they cool down after the expansion due to the increase in temperature, causing the parking force initially established on the high temperature disc to be insufficient to keep the vehicle stationary on slopes after the caliper has cooled down .
  • FIG. 1 is an axonometric view of a brake caliper for a disc brake according to an embodiment of the invention
  • FIG. 1 is a side view of the brake caliper shown in figure 1 ;
  • FIG. 3 is a side view of a brake caliper, sectioned along a plane comprising an axial direction A-A and a radial direction R-R, according to an embodiment of the invention, in which a piston actuatable by a brake fluid and a thrust device can be seen, so as to brake a vehicle as a service brake and as a parking brake, where the piston delimits a ventilation chamber in the direction of a first brake pad which allows thermally insulating a septum of the piston which separates the ventilation chamber from a thrust seat delimited by the piston in which a thrust device immersed in the brake fluid is housable , where a stepped piston sidewall is also visible, which allows reducing the radial dimensions of a pressure chamber in which the brake fluid is introduced by moving the brake fluid away from the first brake pad;
  • FIG. 4 is an axonometric view of a piston according to the present invention, slidingly insertable into a cylinder delimited by the brake caliper in figure 3 , in which the ventilation chamber delimited by the piston can be seen;
  • FIG. 5 is an exploded axonometric view of the piston in figure 4 and a thrust device housable in a thrust seat delimited by the piston and configured to mechanically and/or electromechanically actuate the piston, according to an embodiment of the invention;
  • FIG. 6 is an axonometric view of the piston according to the present invention, sectioned along a plane comprising an axial direction A-A and a radial direction R-R, according to an embodiment of the invention;
  • FIG. 7 is a front view of the piston according to the present invention, in which a first septum surface facing the brake pad can be seen, delimiting a bottom of the pressure chamber, having a raised central portion and two depressed peripheral portions according to an embodiment ;
  • FIG. 8 is a front view of the piston according to the present invention, in which a first surface of the septum facing the brake pad can be seen, delimiting a bottom of the pressure chamber, having a raised circular central portion and a depressed peripheral circular-crown portion according to an embodiment .
  • a piston for a brake caliper 1 is indicated by reference numeral 10 .
  • the piston 10 comprises a side wall 11 mainly extending along an axial direction A-A.
  • the piston 10 comprises a first annular edge configured to come into contact with a first brake pad 4 .
  • the piston 10 comprises a second annular edge 13 configured to receive a thrust from a brake fluid .
  • the side wall 11 extends between the first annular edge 12 and the second annular edge 13 .
  • the piston 10 comprises a septum 14 extending at least along a radial direction R-R, where said radial direction R-R is transverse to said axial direction A-A.
  • Said septum 14 comprises a first pad-side surface 15 adapted to face said first brake pad 4 .
  • Said septum 14 comprises a second brake fluid-side surface 16 adapted to face the opposite side of said first pad-side surface 15 , along said axial direction A-A.
  • Said side wall 11 and said septum 14 delimit a thrust seat 18 and a ventilation chamber 17 , where said thrust seat 18 and said ventilation chamber 17 are fluidically separated along said axial direction A-A by said septum 14 .
  • Said thrust seat 18 is open at said second annular edge 13 and is closed at said second brake fluid-side surface 16.
  • Said thrust seat 18 is adapted to receive at least partially a thrust device 19 to mechanically actuate the piston 10 by biasing said first brake pad 4 .
  • Said ventilation chamber 17 is open at said first annular edge 12 and is closed at least by said first pad-side surface 15.
  • said ventilation chamber 17 is adapted to accommodate air to thermally insulate the septum 14 . Air can thus be trapped between the pad and the septum 14 , reducing the heat transfer from the pad zone to the thrust seat 18 in which the brake fluid is present when the piston is under operating conditions in a brake caliper 1 .
  • said side wall 11 comprises a first side wall portion 20 having a first outer diameter Del and a second side wall portion 21 having a second outer diameter De2 , where said first outer diameter Del is greater than said second outer diameter De2 .
  • Said first side wall portion 20 internally delimits at least said ventilation chamber 17 .
  • Said second side wall portion 21 internally delimits said thrust seat 18 at least partially .
  • Said piston 10 comprises a third annular edge 22 mainly extending along said radial direction R-R, where said third annular edge 22 externally connects said first side wall portion 20 and said second side wall portion 21 in an undercut manner to receive a thrust from said brake fluid .
  • the third annular edge 22 forms a shoulder of said side wall 11 which extends along said radial direction .
  • said septum 14 on the side of said first pad-side surface 15, comprises a central portion 23 and a peripheral portion 24 , where said central portion 23 is raised with respect to said peripheral portion 24 .
  • said peripheral portion 24 is depressed with respect to said central portion 23 . This allows ensuring the air trapping in the ventilation chamber .
  • the geometry of the central portion 23 and the peripheral portion 24 allows increasing a turbulent motion of the air present in the ventilation chamber, avoiding an excessive overheating of the septum 14 .
  • said central portion 23 has a circular shape
  • said peripheral portion 24 has a circular-crown shape about said central portion 23 .
  • said central portion 23 is bone-shaped
  • said peripheral portion 24 is formed by two crescent-shaped portions , separated by said central portion 23 .
  • said first annular edge 12 comprises at least one contact tooth 25 and at least one dip 26, where said at least one contact tooth 25 is raised along said axial direction A-A or a direction parallel to said axial direction A-A with respect to said at least one dip 26 so that when said at least one tooth 25 is in contact with said first brake pad 4 , said dip 26 forms a radial window with said side wall 11 , adapted to allow a passage of air into and out of the ventilation chamber 17 and reduce a contact surface between the first annular edge 12 and the first brake pad 4 .
  • said first annular edge 12 comprises a plurality of said at least one contact tooth 25 and a plurality of said at least one dip 26, arranged circumferentially alternating along said first annular edge 12 .
  • the 20 comprises a first tubular portion 27 .
  • the first tubular portion 27 has a first thickness SI and a first axial length Al .
  • said first tubular portion 27 internally delimits said ventilation chamber 17 . [0045 ] .
  • said second side wall portion is a first tubular portion 27 .
  • said 21 comprises a second tubular portion 28 connected to said first tubular portion 27 .
  • said second tubular portion 28 has a second thickness S2 and a second axial length A2 .
  • said second tubular portion 28 at least partially delimits said thrust seat 18 .
  • said first axial length Al is at least equal to said second axial length A2 .
  • said first thickness SI is at least equal to said second thickness S2 .
  • said second thickness S2 is less than said first thickness S I .
  • said first side wall portion 20 comprises a third tubular portion 29 interposed between said first tubular portion 27 and said second tubular 29.
  • the third tubular portion 29 is connected to the second tubular portion 28 with said third annular edge 22 .
  • the third tubular portion 29 has a third thickness S3 and a third axial length A3 .
  • said third thickness S3 is at least double said first thickness S I .
  • said third axial length A3 is at least double said first thickness SI .
  • said first axial length Al is greater than said third axial length A3 .
  • said first tubular portion 27 and said septum 14 form a cup-shaped portion .
  • said second tubular portion 28 and said third tubular portion 29 and said septum 14 form a T-shaped portion .
  • said third tubular portion 29 forms a restricted shank of said T-shaped portion and said third tubular portion 29 connected to said septum 14 forms a head of said T-shaped portion .
  • said third tubular portion 29 of greater thickness than said first tubular portion and said second tubular portion, and having a length equal to at least half the outer diameter of the first wall portion 20 allows slowing down the overheating and heat transfer from the pad side to the third annular edge 22 facing the brake fluid .
  • said first pad-side surface 15 and said second brake fluid-side surface 16 are diametrically opposite to each other along said axial direction A-A.
  • said first pad-side surface 15 and said second brake fluid-side surface 16 comprise respective central portions mainly extending along directions parallel to said radial direction R-R .
  • said first annular edge 12 and said second annular edge 13 mainly extend along directions parallel to said radial direction R-R and form opposite axial ends of said piston 10 .
  • said first annular edge 12 and said second annular edge 13 mainly extend along a respective circumferential direction C-C punctually orthogonal to said axial direction A-A and said radial direction R-R .
  • said piston 10 has a ventilation chamber depth Pl and a thrust seat depth P2 .
  • Said ventilation chamber depth Pl is defined by a first distance along said axial direction A-A between the central portion of said first pad-side surface 15 and an orthogonal proj ection of said first annular edge 12 on said axial direction A-A.
  • Said thrust seat depth P2 is defined by a distance along said axial direction A-A between the central portion of said second brake fluid-side surface 16 and an orthogonal proj ection of said second annular edge 13 on said axial direction A-A.
  • Said ventilation seat depth Pl is at least half the thrust seat depth P2 .
  • said septum 14 delimits an undercut seat to house an end portion of the thrust device .
  • the undercut seat forms a narrowing of said thrust seat 18 .
  • said thrust seat 18 has a polygonal shape .
  • said piston 10 has a piston axis A parallel to said axial direction A-A about which it extends symmetrically .
  • said side wall 11 comprises an outer side surface which externally delimits said piston 10 with respect to said ventilation chamber 17 and said thrust seat 18 .
  • said outer side surface is a substantially cylindrical surface .
  • said side wall 11 comprises a first inner side surface 30 and a second inner side surface 31 , which delimit said piston 10 by internally facing said ventilation chamber 17 and said thrust seat 18 , respectively .
  • said first inner diameter Dil is equal to at least one third more than said second inner diameter Di l .
  • said first inner diameter Di l is at least double said second inner diameter Di l .
  • 31 is a polygonal surface, such as a parallelepiped side surface, for example with a square base , with rounded corners .
  • the present invention further relates to a brake caliper for a disc brake, generally indicated by reference numeral 1 .
  • the brake caliper 1 comprises at least one piston 10 according to at least one of the previously described embodiments .
  • the brake caliper 1 comprises a caliper body 2 adapted to be arranged straddling a brake disc 32 .
  • Said brake disc 32 has a first braking surface 33 and an opposite second braking surface 34 , said brake disc 3 being adapted to rotate about a rotation axis X-X which defines a direction parallel to said axial direction A-A.
  • Said caliper body 2 comprises a first caliper body portion 6 adapted to face said first braking surface 33 either directly or indirectly .
  • Said caliper body 2 comprises at least one connecting bridge 8 supported by said first caliper body portion 6 and which proj ects straddling said brake disc 32 .
  • Said caliper body 2 comprises a second caliper body portion 7 supported so as to be cantilevered with respect to said at least one floating element bridge 12 and adapted to face said second braking surface 4 either directly or indirectly .
  • Said first caliper body portion 6 internally delimits a piston or cylinder seat 9 adapted to slidingly house said at least one piston 10 in a fluid-tight manner .
  • said first caliper body portion 6 comprises a cylindrical wall 35 and a bottom wall 36 which define said piston or cylinder seat 9.
  • the bottom wall 36 is transverse to the cylindrical wall 35 extending parallel to said radial direction R-R and is made in one piece with said cylindrical wall 35 .
  • said cylindrical wall 35 comprises a first cylindrical portion 37 and a second cylindrical portion 38 connected by a cylinder shoulder 39 mainly extending substantially parallel to said radial direction R-R .
  • said first cylindrical portion 37 slidingly accommodates said first side wall portion 20 of said piston 10 .
  • Said second cylindrical portion 38 slidingly accommodates said second cylindrical wall portion 21 of said piston 10 .
  • said third annular edge 22 faces said cylinder shoulder 39
  • said second annular edge 13 and said thrust seat 18 indirectly face said bottom wall 36 delimiting a pressure chamber in which a brake fluid is inj ected through a conduit 40 passing through said cylinder shoulder 39 to hydraulically bias said piston 10 at least during a service braking action .
  • said brake caliper 1 comprises a thrust device 19 adapted to mechanically bias said piston 10 at least during a parking braking action .
  • said thrust device 19 is partially housed in said thrust seat 18 and within said second cylindrical portion 38 between said bottom wall 36 and said second annular edge 22 of said piston 10 .
  • said thrust device 19 comprises at least one rotating member 41 coupled to a thrust member 42 , where a rotation of said rotating member 41 corresponds to a translation of said thrust member 42 integrally with said piston 10 .
  • said rotating member 41 being rotatably accommodated in a sealing manner inside a rotation seat 43 formed in the bottom wall 36 of the cylinder 9 and passing through said bottom wall 36 so that the rotating member 41 is rotatable about a rotation axis substantially parallel to the axial direction A-A in connection with an electric motor 44 , constrainable to the caliper body 2 .
  • said thrust device 19 comprises a screw-nut screw assembly .
  • said rotating member 41 is a screw
  • said thrust member 42 is a nut screw housed in said thrust seat 18
  • said nut screw comprises a threaded hollow body having a substantially cylindrical shape and a plurality of petals proj ecting radially outward from the hollow body so as to fit into the thrust seat 18 thus allowing the piston 10 to slide forward with respect to said plurality of petals when biased by the brake fluid and allowing the screw nut to advance integrally with the piston when the thrust device 19 biases the piston 10 .
  • said thrust device 19 comprises a ball-in-ramp device , which connects said rotating member 41 to said thrust device 42 .
  • the ball-in-ramp device is known from document US20150323026A1 .
  • said brake caliper 1 comprises a motor unit connected to said caliper body 2 , where said motor unit comprises an electric motor 44 and a reduction gear 45 , where said reduction gear 45 is connected to said rotating member 41 .
  • said brake caliper l is a floating type caliper .
  • the brake caliper 1 comprises a bracket 3 adapted to connect to a caliper support provided in a vehicle .
  • the caliper body 2 is slidingly supported by said bracket 3 so as to move with respect to the bracket 3 along said axial direction A-A.
  • said bracket 3 slidingly supports said first brake pad 4 and said second brake pad 5.
  • said brake caliper 1 is a single-piston caliper .
  • said first caliper body portion 6 has a caliper body shoulder 46 , which externally reduces the radial dimension of the caliper body between the first cylindrical portion 37 and the second cylindrical portion 38 , outside the piston or cylinder seat 9 according to an embodiment .
  • said brake caliper 1 comprises at least one electromechanical parking brake (EPB) .
  • EPB electromechanical parking brake

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Transportation (AREA)
  • Braking Arrangements (AREA)

Abstract

The present invention relates to a piston (10 ) for a brake caliper (1) comprising a side wall (11) mainly extending along an axial direction (A-A) between a first annular edge (12) configured to come into contact with a first brake pad (4) and a second annular edge (13) configured to receive a thrust from a brake fluid, a septum (14) extending at least along a radial direction (R-R), wherein said radial direction (R-R) is transverse to said axial direction (A-A), wherein said septum (14) comprises a first pad-side surface (15) adapted to face said first brake pad (4) and a second brake fluid-side surface (16), wherein said side wall (11) and said septum (14) delimit a thrust seat (18) and a ventilation chamber (17), wherein said thrust seat (18) and said ventilation chamber (17) are fluidically separated along said axial direction (A-A) by said septum (14), wherein said thrust seat (18) is open at said second annular edge (13) and is closed at said second brake fluid-side surface (16), wherein said thrust seat (18) is adapted to receive at least partially a thrust device (19) to mechanically actuate the piston (10) by biasing said first brake pad (4), wherein said ventilation chamber (17) is open at said first annular edge (12) and is closed at least by said first pad-side surface (15), wherein said ventilation chamber (17) is adapted to accommodate air to thermally insulate the septum (14), wherein said side wall (11) comprises a first side wall portion (20) having a first outer diameter (De1) and a second side wall portion (21) having a second outer diameter (De2), wherein said first outer diameter (De1) is greater than said second outer diameter (De2), wherein said first side wall portion (20) internally delimits at least said ventilation chamber (17), wherein said second side wall portion (21) internally delimits said thrust seat (18) at least partially, wherein said piston (10) comprises a third annular edge (22) mainly extending along said radial direction (R-R), wherein said third annular edge (22) externally connects said first side wall portion (20) and said second side wall portion (21) in an undercut manner to receive a thrust from said brake fluid.

Description

"BRAKE CALIPER PISTON AND BRAKE CALIPER"
DESCRIPTION
[0001 ] . Field of the invention
[0002 ] . The present invention relates to a piston for a brake caliper, and to a brake caliper .
[0003] . Background art
[0004 ] . Brake calipers are known, which comprise at least one piston actuatable by both a brake fluid, to act on a brake pad as a service brake, and a mechanically or electrically actuated thrust member, to act on the brake pad as a parking brake , such as an electromechanical parking brake (EBB) , for example .
[0005 ] . Such brake calipers comprise a caliper body, in which a hollow cylinder delimited by a cylindrical wall and a bottom wall , substantially transverse to the cylindrical wall , is obtained . The bottom wall internally delimits a through-seat adapted to house in a sealed and rotational manner at least one portion of a rotating member connectable , on one side, to an actuating mechanism, such as an electric motor, and on the other side to the thrust member connectable to the piston . The piston comprises a thrust head adapted to come into contact with the brake pad and a side wall adapted to sealingly slide with respect to the cylindrical wall . Moreover, with said thrust head and said side wall , the piston delimits an open cavity on the side opposite to the thrust head, adapted to accommodate at least partially the thrust member coupled to the rotating member of the parking brake device . The thrust member is coupled to the rotating member so as to transform the rotation of the rotating member into a translation of the thrust member, which allows a displacement in the axial direction by biasing the brake pad .
[0006] . In brake calipers of this type , the brake fluid is fluid- tightly introduced between the bottom wall of the cylinder and the piston, which allows the piston to be actuated by virtue of the fluid pressure, where the rotating member and the thrust member are immersed in the brake fluid and allow the piston to be actuated as a parking brake regardless of the action of the fluid .
[0007 ] . With the operation of the brake caliper as a service brake, the interaction between brake pads and disc generates heat that reaches high temperatures , of the order of hundreds of degrees , which is transferred to caliper body and piston thus increasing the temperature of the brake fluid .
[0008 ] . As known, in the brake calipers of disc brakes , air bubbles are created in the braking system when the brake fluid becomes excessively hot approaching the boiling point . These bubbles , unlike the brake fluid being substantially incompressible, can lead to an increase in the stroke of the brake actuating device , such as a pedal or lever, for example, to compress such gas bubbles during a braking action, compromising the braking comfort and potentially compromising the braking action itself .
[0009] . In addition to such a problem, in such calipers , an excessive increase in temperature of the brake fluid can lead to the expansion of the components of the thrust member and the rotating member, which are immersed in the brake fluid, and subsequent contraction during cooling . It has been found that heating and cooling cycles , and the resulting subsequent expansions and contractions of the components immersed in the brake fluid of the parking system in the cylinder chamber, can lead to impaired operation of the parking brake until the brake caliper cools down . [0010 ] . Additionally, the excessive heating of the braking fluid adds a risk factor to the reliability of the parking brake when activated with a vehicle on a slope after the service brake has been repeatedly activated . Indeed, since the disc, the pads , as well as the thrust member and the rotating member are immersed in the braking fluid, they reduce their si ze as they cool down after the expansion due to the increase in temperature, causing the parking force initially established on the high temperature disc to be insufficient to keep the vehicle stationary on slopes after the caliper has cooled down .
[0011 ] . Therefore , the need is strongly felt to devise brake caliper solutions which allow avoiding excessive overheating of the braking fluid .
[0012 ] . In addition, one of the needs felt in the field is to manufacture a disc brake caliper which is as light as possible , so as to limit as much as possible the unsprung masses of the vehicle with which the disc brake is associated, and on the other hand, the need to ensure a necessary stiffness of the caliper body, to prevent it from deforming in use and compromising the braking action . In particular, any deformations of the caliper body can compromise the sliding thereof with respect to the bracket , and thus there can be an incorrect distribution of the thrusts acting on the pads acting on opposite faces of the braking band . Obviously, such needs for stif fness and lightness are antithetical since increased stiffness is normally achieved by increasing component thicknesses and related masses .
[0013] . Solut ion
[0014 ] . It is the obj ect of the present invention to provide a brake piston and a brake caliper which allow better resistance to the increase in temperature of the braking fluid than known so far .
[0015 ] . It is a further obj ect of the present invention to provide a piston and a brake caliper which allow obtaining high resistance to brake fluid temperature increase by limiting the space available for brake fluid in the caliper body, i . e . , by limiting the si ze of the pressure chamber delimited between piston and cylinder made in the caliper body, reducing the weight of the brake caliper and maintaining high resistance to stress .
[0016] . These and other obj ects are achieved by a piston according to claim 1 and by a brake caliper according to claim 8 .
[0017 ] . The dependent claims relate to preferred and advantageous embodiments of the present invention .
[0018 ] . Drawings
[0019] . In order to better understand the invention and appreciate the advantages thereof , some non-limiting exemplary embodiments thereof will be described below with reference to the accompanying drawings , in which : [0020 ] . - figure 1 is an axonometric view of a brake caliper for a disc brake according to an embodiment of the invention;
[0021 ] . - figure 2 is a side view of the brake caliper shown in figure 1 ;
[0022 ] . - figure 3 is a side view of a brake caliper, sectioned along a plane comprising an axial direction A-A and a radial direction R-R, according to an embodiment of the invention, in which a piston actuatable by a brake fluid and a thrust device can be seen, so as to brake a vehicle as a service brake and as a parking brake, where the piston delimits a ventilation chamber in the direction of a first brake pad which allows thermally insulating a septum of the piston which separates the ventilation chamber from a thrust seat delimited by the piston in which a thrust device immersed in the brake fluid is housable , where a stepped piston sidewall is also visible, which allows reducing the radial dimensions of a pressure chamber in which the brake fluid is introduced by moving the brake fluid away from the first brake pad;
[0023] . - figure 4 is an axonometric view of a piston according to the present invention, slidingly insertable into a cylinder delimited by the brake caliper in figure 3 , in which the ventilation chamber delimited by the piston can be seen;
[0024 ] . - figure 5 is an exploded axonometric view of the piston in figure 4 and a thrust device housable in a thrust seat delimited by the piston and configured to mechanically and/or electromechanically actuate the piston, according to an embodiment of the invention; [0025 ] . - figure 6 is an axonometric view of the piston according to the present invention, sectioned along a plane comprising an axial direction A-A and a radial direction R-R, according to an embodiment of the invention;
[0026] . - figure 7 is a front view of the piston according to the present invention, in which a first septum surface facing the brake pad can be seen, delimiting a bottom of the pressure chamber, having a raised central portion and two depressed peripheral portions according to an embodiment ;
[0027 ] . - figure 8 is a front view of the piston according to the present invention, in which a first surface of the septum facing the brake pad can be seen, delimiting a bottom of the pressure chamber, having a raised circular central portion and a depressed peripheral circular-crown portion according to an embodiment .
[0028 ] . Description of some preferred embodiments
[0029] . According to a general embodiment, a piston for a brake caliper 1 is indicated by reference numeral 10 .
[0030 ] . The piston 10 comprises a side wall 11 mainly extending along an axial direction A-A. The piston 10 comprises a first annular edge configured to come into contact with a first brake pad 4 . The piston 10 comprises a second annular edge 13 configured to receive a thrust from a brake fluid . The side wall 11 extends between the first annular edge 12 and the second annular edge 13 . [0031 ] . The piston 10 comprises a septum 14 extending at least along a radial direction R-R, where said radial direction R-R is transverse to said axial direction A-A. [0032 ] . Said septum 14 comprises a first pad-side surface 15 adapted to face said first brake pad 4 . Said septum 14 comprises a second brake fluid-side surface 16 adapted to face the opposite side of said first pad-side surface 15 , along said axial direction A-A.
[0033] . Said side wall 11 and said septum 14 delimit a thrust seat 18 and a ventilation chamber 17 , where said thrust seat 18 and said ventilation chamber 17 are fluidically separated along said axial direction A-A by said septum 14 .
[0034 ] . Said thrust seat 18 is open at said second annular edge 13 and is closed at said second brake fluid-side surface 16.
[0035 ] . Said thrust seat 18 is adapted to receive at least partially a thrust device 19 to mechanically actuate the piston 10 by biasing said first brake pad 4 .
[0036] . Said ventilation chamber 17 is open at said first annular edge 12 and is closed at least by said first pad-side surface 15.
[0037 ] . Advantageously, said ventilation chamber 17 is adapted to accommodate air to thermally insulate the septum 14 . Air can thus be trapped between the pad and the septum 14 , reducing the heat transfer from the pad zone to the thrust seat 18 in which the brake fluid is present when the piston is under operating conditions in a brake caliper 1 .
[0038 ] . Advantageously, said side wall 11 comprises a first side wall portion 20 having a first outer diameter Del and a second side wall portion 21 having a second outer diameter De2 , where said first outer diameter Del is greater than said second outer diameter De2 . Said first side wall portion 20 internally delimits at least said ventilation chamber 17 . Said second side wall portion 21 internally delimits said thrust seat 18 at least partially .
[0039] . Said piston 10 comprises a third annular edge 22 mainly extending along said radial direction R-R, where said third annular edge 22 externally connects said first side wall portion 20 and said second side wall portion 21 in an undercut manner to receive a thrust from said brake fluid . In other words , the third annular edge 22 forms a shoulder of said side wall 11 which extends along said radial direction .
[0040 ] . According to an embodiment , said septum 14 , on the side of said first pad-side surface 15, comprises a central portion 23 and a peripheral portion 24 , where said central portion 23 is raised with respect to said peripheral portion 24 . According to an embodiment, said peripheral portion 24 is depressed with respect to said central portion 23 . This allows ensuring the air trapping in the ventilation chamber . Moreover, when air enters the ventilation chamber, the geometry of the central portion 23 and the peripheral portion 24 allows increasing a turbulent motion of the air present in the ventilation chamber, avoiding an excessive overheating of the septum 14 .
[0041 ] . According to an embodiment, said central portion 23 has a circular shape , and said peripheral portion 24 has a circular-crown shape about said central portion 23 . According to an embodiment, said central portion 23 is bone-shaped, and said peripheral portion 24 is formed by two crescent-shaped portions , separated by said central portion 23 .
[0042 ] . According to an embodiment , said first annular edge 12 comprises at least one contact tooth 25 and at least one dip 26, where said at least one contact tooth 25 is raised along said axial direction A-A or a direction parallel to said axial direction A-A with respect to said at least one dip 26 so that when said at least one tooth 25 is in contact with said first brake pad 4 , said dip 26 forms a radial window with said side wall 11 , adapted to allow a passage of air into and out of the ventilation chamber 17 and reduce a contact surface between the first annular edge 12 and the first brake pad 4 .
[0043] . According to an embodiment , said first annular edge 12 comprises a plurality of said at least one contact tooth 25 and a plurality of said at least one dip 26, arranged circumferentially alternating along said first annular edge 12 .
[0044 ] . According to an embodiment, said first side wall portion
20 comprises a first tubular portion 27 . According to a first embodiment, the first tubular portion 27 has a first thickness SI and a first axial length Al . According to an embodiment , said first tubular portion 27 internally delimits said ventilation chamber 17 . [0045 ] . According to an embodiment, said second side wall portion
21 comprises a second tubular portion 28 connected to said first tubular portion 27 . According to an embodiment, said second tubular portion 28 has a second thickness S2 and a second axial length A2 . According to an embodiment, said second tubular portion 28 at least partially delimits said thrust seat 18 .
[0046] . According to an embodiment, said first axial length Al is at least equal to said second axial length A2 .
[0047 ] . According to an embodiment, said first thickness SI is at least equal to said second thickness S2 . According to an embodiment, said second thickness S2 is less than said first thickness S I .
[0048 ] . According to an embodiment, said first side wall portion 20 comprises a third tubular portion 29 interposed between said first tubular portion 27 and said second tubular 29. According to an embodiment, the third tubular portion 29 is connected to the second tubular portion 28 with said third annular edge 22 .
[0049] . According to a first embodiment , the third tubular portion 29 has a third thickness S3 and a third axial length A3 .
[0050 ] . According to an embodiment, said third thickness S3 is at least double said first thickness S I .
[0051 ] . According to an embodiment, said third axial length A3 is at least double said first thickness SI .
[0052 ] . According to an embodiment, said first axial length Al is greater than said third axial length A3 .
[0053] . According to an embodiment, said first tubular portion 27 and said septum 14 form a cup-shaped portion .
[0054 ] . According to an embodiment, said second tubular portion 28 and said third tubular portion 29 and said septum 14 form a T-shaped portion . According to an embodiment , said third tubular portion 29 forms a restricted shank of said T-shaped portion and said third tubular portion 29 connected to said septum 14 forms a head of said T-shaped portion .
[0055 ] . Advantageously, the provision of said third tubular portion 29 of greater thickness than said first tubular portion and said second tubular portion, and having a length equal to at least half the outer diameter of the first wall portion 20 , allows slowing down the overheating and heat transfer from the pad side to the third annular edge 22 facing the brake fluid .
[0056] . According to an embodiment, said first pad-side surface 15 and said second brake fluid-side surface 16 are diametrically opposite to each other along said axial direction A-A.
[0057 ] . According to an embodiment, said first pad-side surface 15 and said second brake fluid-side surface 16 comprise respective central portions mainly extending along directions parallel to said radial direction R-R .
[0058 ] . According to an embodiment, said first annular edge 12 and said second annular edge 13 mainly extend along directions parallel to said radial direction R-R and form opposite axial ends of said piston 10 .
[0059] . According to an embodiment, said first annular edge 12 and said second annular edge 13 mainly extend along a respective circumferential direction C-C punctually orthogonal to said axial direction A-A and said radial direction R-R .
[0060 ] . According to an embodiment , said piston 10 has a ventilation chamber depth Pl and a thrust seat depth P2 . Said ventilation chamber depth Pl is defined by a first distance along said axial direction A-A between the central portion of said first pad-side surface 15 and an orthogonal proj ection of said first annular edge 12 on said axial direction A-A. Said thrust seat depth P2 is defined by a distance along said axial direction A-A between the central portion of said second brake fluid-side surface 16 and an orthogonal proj ection of said second annular edge 13 on said axial direction A-A. Said ventilation seat depth Pl is at least half the thrust seat depth P2 .
[0061 ] . According to an embodiment, on the side of said second brake fluid-side surface 16, said septum 14 delimits an undercut seat to house an end portion of the thrust device . The undercut seat forms a narrowing of said thrust seat 18 .
[0062 ] . According to an embodiment, said thrust seat 18 has a polygonal shape .
[0063] . According to an embodiment, said piston 10 has a piston axis A parallel to said axial direction A-A about which it extends symmetrically .
[0064 ] . According to an embodiment, said side wall 11 comprises an outer side surface which externally delimits said piston 10 with respect to said ventilation chamber 17 and said thrust seat 18 . According to an embodiment, said outer side surface is a substantially cylindrical surface .
[0065 ] . According to an embodiment, said side wall 11 comprises a first inner side surface 30 and a second inner side surface 31 , which delimit said piston 10 by internally facing said ventilation chamber 17 and said thrust seat 18 , respectively .
[0066] . According to an embodiment, said first inner side surface
30 has a first inner diameter Di l and said second inner side surface
31 has a second inner diameter Di l .
[0067 ] . According to an embodiment, said first inner diameter Dil is equal to at least one third more than said second inner diameter Di l . According to an embodiment , said first inner diameter Di l is at least double said second inner diameter Di l .
[0068 ] . According to an embodiment, said first inner side surface
30 is a substantially cylindrical surface .
[0069] . According to an embodiment, said second inner side surface
31 is a polygonal surface, such as a parallelepiped side surface, for example with a square base , with rounded corners .
[0070 ] . The present invention further relates to a brake caliper for a disc brake, generally indicated by reference numeral 1 .
[0071 ] . The brake caliper 1 comprises at least one piston 10 according to at least one of the previously described embodiments .
[0072 ] . The brake caliper 1 comprises a caliper body 2 adapted to be arranged straddling a brake disc 32 . Said brake disc 32 has a first braking surface 33 and an opposite second braking surface 34 , said brake disc 3 being adapted to rotate about a rotation axis X-X which defines a direction parallel to said axial direction A-A.
[0073] . Said caliper body 2 comprises a first caliper body portion 6 adapted to face said first braking surface 33 either directly or indirectly . Said caliper body 2 comprises at least one connecting bridge 8 supported by said first caliper body portion 6 and which proj ects straddling said brake disc 32 . Said caliper body 2 comprises a second caliper body portion 7 supported so as to be cantilevered with respect to said at least one floating element bridge 12 and adapted to face said second braking surface 4 either directly or indirectly .
[0074 ] . Said first caliper body portion 6 internally delimits a piston or cylinder seat 9 adapted to slidingly house said at least one piston 10 in a fluid-tight manner .
[0075 ] . According to an embodiment, said first caliper body portion 6 comprises a cylindrical wall 35 and a bottom wall 36 which define said piston or cylinder seat 9. The bottom wall 36 is transverse to the cylindrical wall 35 extending parallel to said radial direction R-R and is made in one piece with said cylindrical wall 35 .
[0076] . According to an embodiment, said cylindrical wall 35 comprises a first cylindrical portion 37 and a second cylindrical portion 38 connected by a cylinder shoulder 39 mainly extending substantially parallel to said radial direction R-R .
[0077 ] . According to an embodiment , said first cylindrical portion 37 slidingly accommodates said first side wall portion 20 of said piston 10 . Said second cylindrical portion 38 slidingly accommodates said second cylindrical wall portion 21 of said piston 10 . [0078 ] . According to an embodiment , said third annular edge 22 faces said cylinder shoulder 39 , and said second annular edge 13 and said thrust seat 18 indirectly face said bottom wall 36 delimiting a pressure chamber in which a brake fluid is inj ected through a conduit 40 passing through said cylinder shoulder 39 to hydraulically bias said piston 10 at least during a service braking action .
[0079] . According to an embodiment, said brake caliper 1 comprises a thrust device 19 adapted to mechanically bias said piston 10 at least during a parking braking action .
[0080 ] . According to an embodiment, said thrust device 19 is partially housed in said thrust seat 18 and within said second cylindrical portion 38 between said bottom wall 36 and said second annular edge 22 of said piston 10 .
[0081 ] . According to an embodiment, said thrust device 19 comprises at least one rotating member 41 coupled to a thrust member 42 , where a rotation of said rotating member 41 corresponds to a translation of said thrust member 42 integrally with said piston 10 . [0082 ] . According to an embodiment, said rotating member 41 being rotatably accommodated in a sealing manner inside a rotation seat 43 formed in the bottom wall 36 of the cylinder 9 and passing through said bottom wall 36 so that the rotating member 41 is rotatable about a rotation axis substantially parallel to the axial direction A-A in connection with an electric motor 44 , constrainable to the caliper body 2 . [0083] . According to an embodiment, said thrust device 19 comprises a screw-nut screw assembly . According to an embodiment, said rotating member 41 is a screw, and said thrust member 42 is a nut screw housed in said thrust seat 18 . According to an embodiment, said nut screw comprises a threaded hollow body having a substantially cylindrical shape and a plurality of petals proj ecting radially outward from the hollow body so as to fit into the thrust seat 18 thus allowing the piston 10 to slide forward with respect to said plurality of petals when biased by the brake fluid and allowing the screw nut to advance integrally with the piston when the thrust device 19 biases the piston 10 .
[0084 ] . According to an embodiment, said thrust device 19 comprises a ball-in-ramp device , which connects said rotating member 41 to said thrust device 42 . For example, the ball-in-ramp device is known from document US20150323026A1 .
[0085 ] . According to an embodiment, said brake caliper 1 comprises a motor unit connected to said caliper body 2 , where said motor unit comprises an electric motor 44 and a reduction gear 45 , where said reduction gear 45 is connected to said rotating member 41 .
[0086] . According to an embodiment, said brake caliper l is a floating type caliper .
[0087 ] . According to an embodiment, the brake caliper 1 comprises a bracket 3 adapted to connect to a caliper support provided in a vehicle . According to an embodiment , the caliper body 2 is slidingly supported by said bracket 3 so as to move with respect to the bracket 3 along said axial direction A-A.
[0088 ] . According to an embodiment, said bracket 3 slidingly supports said first brake pad 4 and said second brake pad 5.
According to an embodiment, said brake caliper 1 is a single-piston caliper .
[0089] . According to an embodiment, said first caliper body portion 6 has a caliper body shoulder 46 , which externally reduces the radial dimension of the caliper body between the first cylindrical portion 37 and the second cylindrical portion 38 , outside the piston or cylinder seat 9 according to an embodiment .
[0090 ] . According to an embodiment, said brake caliper 1 comprises at least one electromechanical parking brake (EPB) .
[0091 ] . Obviously, those skilled in the art will be able to make changes or adaptations to the present invention, without however departing from the scope of the following claims .
LIST OF REFERENCE SIGNS ad pad body portion or first elongated portion ted portion or second caliper body portion idge inder seat edge or thrust edge r edge nsverse septum e surface fluid-side surface hamber ll portion all portion edge m portion ptum portion portion r portion portion ide surface side surface 33. First braking surface
34 . Second braking surface
35 . Cylindrical wall
36. Bottom wall
37 . Fi rst cylindrical portion
38 . Second cylindrical portion
39. Cylinder shoulder
40 . Conduit
41 . Rotating member
42 . Thrust member
43. Rotation seat
44 . Electric motor
45 . Reduction gear
46. Caliper body shoulder
Del First outer diameter
De2 Second outer diameter
Dil First inner diameter
Di2 Second inner diameter
51 First thickness
52 Second thickness
53 Third thickness
Al First axial length
A2 Second axial length
A3 Third axial length
Pl Ventilation chamber depth
P2 Thrust seat depth
A Piston axis
X-X Disc axis
Del First outer diameter

Claims

1. A piston (10) for a brake caliper (1) comprising a side wall (11) developing prevalently along an axial direction (A- A) between a first annular edge (12) configured to come into contact with a first brake pad (4) and a second annular edge (13) configured to receive a thrust from a brake fluid, a septum (14) extending at least along a radial direction (R-R) , wherein said radial direction (R-R) is transverse to said axial direction (A-A) , wherein said septum (14) comprises a first pad-side surface (15) adapted to face said first brake pad (4) and a second brake fluid-side surface (16) , wherein said side wall (11) and said septum (14) delimit a thrust seat (18) and a ventilation chamber (17) , wherein said thrust seat
(18) and said ventilation chamber (17) are fluidically separated along said axial direction (A-A) by said septum (14) , wherein said thrust seat (18) is open at said second annular edge (13) and is closed at said second brake fluid-side surface (16) , wherein said thrust seat (18) is adapted to receive a thrust device
(19) to at least partially mechanically actuate the piston (10) biasing said first brake pad (4) , wherein said ventilation chamber (17) is open at said first annular edge (12) and is closed at least by said first pad-side surface (15) , wherein said ventilation chamber (17) is adapted to receive air to thermally insulate the septum (14) , wherein said side wall (11) comprises a first side wall portion (20) having a first outer diameter (Del) and a second side wall portion (21) having a second outer diameter (De2) , wherein said first outer diameter (Del) is greater than said second outer diameter (De2) , wherein said first side wall portion (20) internally delimits at least said ventilation chamber (17) , wherein said second side wall portion (21) internally delimits said thrust seat (18) at least partially, wherein said piston (10) comprises a third annular edge (22) developing prevalently along said radial direction (R-R) , wherein said third annular edge (22) externally undercut connects said first side wall portion (20) and said second side wall portion (21) to receive a thrust from said brake fluid.
2. Piston (10) according to the preceding claim, wherein said septum (14) , on the side of said first pad-side surface (15) , comprises a central portion (23) and a peripheral portion (24) , wherein said central portion (23) is in relief relative to said peripheral portion (24) and/or wherein said peripheral portion (24) is depressed relative to said central portion (23) .
3. Piston (10) according to the preceding claim, wherein said central portion (23) has a circular or bone shape, and wherein said peripheral portion (24) has a circular crown or crescent shape.
4. Piston (10) according to any of the preceding claims, wherein said first annular edge (12) comprises at least one contact tooth (25) and at least one dip (26) , wherein said at least one contact tooth (25) is in relief along said axial direction (A-A) or a direction parallel to said axial direction (A-A) with respect to said at least one dip (26) so that when said at least one tooth (25) is in contact with said first brake pad (4) , said dip (26) forms a radial window with said side wall (11) adapted to allow a passage of air into and out of the ventilation chamber (17) and reduce a contact surface between the first annular edge (12) and the first brake pad ( 4 ) .
5. Piston (10) according to the preceding claim, wherein said central portion (23) has a circular or bone shape, and wherein said peripheral portion (24) has a circular crown or crescent shape; and/or wherein said first annular edge (12) comprises a plurality of said at least one contact tooth (25) and a plurality of said at least one dip (26) , arranged circumferentially alternating along said first annular edge (12) .
6. Piston (10) according to any of the preceding claims, wherein said first side wall portion (20) comprises a first tubular portion (27) , wherein the first tubular portion (27) has a first thickness (SI) and a first axial length (Al) , wherein said second side wall portion (21) comprises a second tubular portion (28) connected to said first tubular portion (27) , wherein said second tubular portion (28) has a second thickness (S2) and a second axial length (A2) , wherein said first axial length (Al ) is at least equal to said second axial length (A2 ) , wherein said first thickness (SI) is at least equal to said second thickness ( S 2 ) , wherein said first tubular portion (27) internally delimits said ventilation chamber (17) , wherein said second tubular portion () at least partially delimits said thrust seat (18) .
7. Piston (10) according to the preceding claim, wherein said wall side first portion (20) comprises a third tubular portion (29) interposed between said first tubular portion (27) and said second tubular portion (29) , wherein the third tubular portion (29) is connected to the second tubular portion (28) by said third annular edge (22) , wherein the third tubular portion (29) has a third thickness (S3) and a third axial length (A3) , wherein said third thickness (S3) is at least twice as thick as said first thickness (SI) , wherein said third thickness (A3) is double to said first thickness (SI) , wherein said first axial length (Al) is greater than said third axial length (A3) , so that said third tubular portion (29) forms a radiator portion between the third annular edge (22) facing the brake fluid and the first tubular portion (27) ; and/or wherein said first tubular portion (27) and said septum (14) form a cup-shaped portion.
8. Piston (10) according to the preceding claim, wherein said first tubular portion (27) and said septum (14) form a cup-shaped portion, and/or wherein said second tubular portion (28) and said third tubular portion (29) and said septum (14) form a T-shaped portion, wherein said third tubular portion (29) forms a restricted shank of said T-shaped portion and said third tubular portion (29) connected to said septum (14) forms a head of said T-shaped portion.
9. Piston (10) according to any one of the preceding claims, wherein said first pad-side surface (15) and said second brake fluid-side surface (16) are diametrically opposite along said axial direction (A-A) , wherein said first pad-side surface (15) and said second brake fluid-side surface (16) comprise respective central portions which extend prevalently along directions parallel to said radial direction (R-R) , wherein said first annular edge (12) and said second annular edge (13) extend prevalently along directions parallel to said radial direction (R-R) and form opposite axial ends of said piston (10) , wherein said first annular edge (12) and said second annular edge (13) extend prevalently along a respective circumferential direction (C-C) accurately orthogonal to said axial direction (A-A) and said radial direction (R-R) , wherein said piston (10) has a ventilation chamber depth (Pl) and a thrust seat depth (P2) , wherein said thrust chamber depth (Pl) is defined by a first distance along said axial direction (A-A) between the central portion of said first pad-side surface (15) and an orthogonal projection of said first annular edge (12) on said axial direction (A-A) , and wherein said thrust seat depth (P2) is defined by a distance along the axial direction (A-A) between the central portion of said second brake fluid-side surface (16) and an orthogonal projection of said second annular edge (13) on said axial direction (A-A) , wherein said ventilation seat depth (Pl) is at least half the thrust seat depth (P2) .
10. Piston (10) according to any one of the preceding claims, wherein said side wall (11) comprises an outer side surface which delimits said piston (10) externally with respect to said ventilation chamber (17) and said thrust seat (18) , wherein said side wall (11) comprises a first inner side surface (30) and a second inner side surface (31) , which delimit said piston (10) internally facing said ventilation chamber (17) and said thrust seat (18) , respectively, wherein said first inner side surface (30) has a first inner diameter (Dil) and said second inner side surface (31) has a second inner diameter (Dil) , wherein said first inner diameter (Dil) is at least one-third more, preferably at least twice as large, with respect to said second inner diameter (Dil) .
11. Piston (10) according to the preceding claim, wherein said outer side surface is a substantially cylindrical surface, and/or wherein said first inner side surface (30) is a substantially cylindrical surface, and/or where said second inner side surface (31) is a polygonal surface, such as a side surface of a square base parallelepiped.
12. A brake caliper (1) for brake disc caliper of the floating type, comprising : at least one piston (10) according to any one of the preceding claims, a caliper body (2) adapted to straddle a brake disc (32) , said brake disc (32) having a first braking surface (33) and an opposite second braking surface (34) , said brake disc (3) being adapted to rotate about a rotation axis (X-X) defining a direction parallel to said axial (A-A) , wherein said caliper body (2) comprises a first caliper body portion (6) adapted to face said first braking surface (33) either directly or indirectly; wherein said caliper body element (2) comprises at least one connecting bridge (8) supported by said first floating element portion (6) and which protrudes straddling said brake disc (32) ; wherein said caliper body (2) comprises a second caliper body portion (7) cantilever-supported to said at least one floating element bridge (12) and adapted to face said second braking surface (4) either directly or indirectly, wherein said first caliper body portion (6) internally delimits a piston or cylinder seat (9) adapted to house said at least one piston (10) in a fluid-tight manner, wherein said first caliper body portion (6) comprises a cylindrical wall (35) and a rear wall (36) which define said piston or cylinder seat (9) , wherein the rear wall (36) is transverse to the cylindrical wall (35) extending parallel to said radial direction (R-R) and is made in one piece with said cylindrical wall (35) ; wherein said cylindrical wall (35) comprises a first cylindrical portion (37) and a second cylindrical portion (38) connected by a cylinder shoulder (39) extending prevalently parallel to said radial direction (R-R) , wherein said first cylindrical portion (37) slidingly accommodates said first side wall portion (20) of said piston (10) , wherein said second cylindrical portion (38) slidingly accommodates said second cylindrical wall portion (21) of said piston (10) , wherein said third annular edge (22) faces said cylinder shoulder (39) and wherein said second annular edge (13) and said thrust seat (18) are indirectly facing said back wall (36) delimiting a pressure chamber into which a brake fluid is injected through a conduit (40) passing through said cylinder shoulder (39) to hydraulically stress said piston (10) at least during a service braking, wherein said brake caliper (1) comprises a thrust device (19) adapted to mechanically stress said piston (10) at least during a parking-braking, wherein said thrust device (19) is partially housed in said thrust seat (18) and within said second cylindrical portion (38) between said bottom wall (36) and said second annular edge (22) of said piston (10) , wherein said thrust device (19) comprises at least one rotating member (41) coupled with a thrust member (42) ; said rotating member (41) being rotatably accommodated in a sealing manner in a rotation seat (43) formed in the bottom wall (36) of the cylinder (9) and passing through said bottom wall (36) so that the rotating member (41) is rotatable about a rotation axis substantially parallel to the axial direction (A-A) in connection with an electric motor (44) , constrainable to the caliper body (2) , wherein a rotation of said rotating member (41) corresponds to a translation of said thrust member (42) integrally with said piston (10) .
13. Brake caliper (1) according to the preceding claim, wherein said first caliper body portion (6) comprises a cylindrical wall (35) and a rear wall (36) which define said piston or cylinder seat (9) , wherein the rear wall (36) is transverse to the cylindrical wall (35) extending parallel to said radial direction (R-R) and is made in one piece with said cylindrical wall (35) ; wherein said cylindrical wall (35) comprises a first cylindrical portion (37) and a second cylindrical portion (38) connected by a cylinder shoulder (39) extending prevalently parallel to said radial direction (R-R) , wherein said first cylindrical portion (37) slidingly accommodates said first side wall portion (20) of said piston (10) , wherein said second cylindrical portion (38) slidingly accommodates said second cylindrical wall portion (21) of said piston (10) , wherein said third annular edge (22) faces said cylinder shoulder (39) and wherein said second annular edge (13) and said thrust seat (18) are indirectly facing said back wall (36) delimiting a pressure chamber into which a brake fluid is injected through a conduit (40) passing through said cylinder shoulder (39) to hydraulically stress said piston (10) at least during a service braking, wherein said brake caliper (1) comprises a thrust device (19) adapted to mechanically stress said piston (10) at least during a parking-braking, wherein said thrust device (19) is partially housed in said thrust seat (18) and within said second cylindrical portion (38) between said bottom wall (36) and said second annular edge (22) of said piston (10) , wherein said thrust device (19) comprises at least one rotating member (41) coupled with a thrust member (42) ; said rotating member (41) being rotatably accommodated in a sealing manner in a rotation seat (43) formed in the bottom wall (36) of the cylinder (9) and passing through said bottom wall (36) so that the rotating member (41) is rotatable about a rotation axis substantially parallel to the axial direction (A-A) in connection with an electric motor (44) , constrainable to the caliper body (2) , wherein a rotation of said rotating member (41) corresponds to a translation of said thrust member (42) integrally with said piston (10) .
14. Brake caliper (1) according to the preceding claim, wherein said thrust device (19) comprises a screw-nut assembly, wherein said rotating member (41) is a screw, and said thrust device (42) is a nut-screw housed in said thrust seat (18) , or wherein said thrust device (19) comprises a ball-in-ramp device, which connects said rotating member (41) to said thrust device (42) , and/or wherein said brake caliper (1) comprises a motor unit connected to said caliper body (2) , wherein said motor unit comprises an electric motor (44) , and a reduction gear (45) , wherein said reduction gear (45) is connected to said rotating member (41) , and/or wherein said brake caliper (1) is a caliper of the floating type, comprising a bracket (3) adapted to connect to a caliper bracket provided in a vehicle; wherein said bracket (3) slidingly supports said first brake pad (4) and said second brake pad (5) , wherein a caliper body (2) is supported in a sliding manner by said bracket (3) to move relative to the bracket (3) along said axial direction (A-A) , and/or wherein said brake caliper (1) is a mono-piston caliper.
15. Brake caliper (1) according to any one of the claims from 12 to 14, wherein said first caliper body portion (6) has a caliper body shoulder (46) which externally reduces the radial dimension of the caliper body between the first cylindrical portion (37) and the second cylindrical portion (38) , externally to the piston or cylinder seat (9) .
EP23738877.2A 2022-06-23 2023-06-20 Brake caliper piston and brake caliper Pending EP4544202A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102022000013279A IT202200013279A1 (en) 2022-06-23 2022-06-23 BRAKE CALIPER PISTON, BRAKE CALIPER
PCT/IB2023/056361 WO2023248118A1 (en) 2022-06-23 2023-06-20 Brake caliper piston and brake caliper

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EP4544202A1 true EP4544202A1 (en) 2025-04-30

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CN (1) CN119790246A (en)
IT (1) IT202200013279A1 (en)
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CN120969377B (en) * 2025-10-21 2026-01-02 浙江万安科技股份有限公司 A vehicle control system and a vehicle

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US3770082A (en) * 1972-11-29 1973-11-06 Gen Motors Corp Disc brake caliper assembly
DE3410006A1 (en) * 1984-03-19 1985-09-19 Alfred Teves Gmbh, 6000 Frankfurt METHOD FOR CONTROLLING A BRAKE SYSTEM FOR MOTOR VEHICLES, AND DEVICE FOR IMPLEMENTING THE METHOD
DE10034364C2 (en) * 2000-07-14 2002-09-05 Alcon Components Ltd caliper
JP4253682B2 (en) * 2003-12-19 2009-04-15 ローベルト ボツシユ ゲゼルシヤフト ミツト ベシユレンクテル ハフツング Automated parking brake
US7264093B2 (en) * 2004-05-17 2007-09-04 Advics Co., Ltd. Combined service and parking brake apparatus
CN104919216A (en) 2012-12-18 2015-09-16 Ntn株式会社 Ball ramp mechanism with direct actuator and electric disc brake unit

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WO2023248118A1 (en) 2023-12-28
CN119790246A (en) 2025-04-08

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