Caliper brake device comprising a sealing ring fitted onto a push head

Abstract

Braking device (5) for a caliper brake (1), comprising a push head (33) and a sealing ring (34) fitted onto an axial end of the push head (33). The ring (34) preferably abuts against a shoulder of the push head (33). Corresponding assembly method. Figure for the abbreviation: Fig. 2

Description

Title of the invention: Device for a caliper brake comprising a sealing ring fitted onto a push head. Technical field

[0001] The invention relates to the field of caliper brakes, in particular floating caliper brakes for motor vehicles.

[0002] The invention is of particular interest, not limiting in any way, for electrically operated brakes, in particular fully electrically operated brakes, also called electro-mechanical brakes (“Electro-Mechanical Brake (EMB)” in English). State of the art

[0003] Floating caliper brakes known in the prior art comprise one or more pistons enabling a braking force to be exerted on a wheel disc via brake pads.

[0004] There is a need to improve the architecture of such brakes, in particular to facilitate assembly operations and / or reduce their manufacturing cost, while providing an architecture capable of withstanding variable counter-braking forces. Description of the invention

[0005] The invention aims to improve prior art caliper brakes, including those with hydraulic actuation.

[0006] To this end, the invention relates to a braking device for a caliper brake, comprising a piston intended to be moved relative to a caliper body in translation along a longitudinal axis selectively in a first braking direction and in a second direction opposite to the first direction, the piston comprising a push head and a ring intended to prevent or limit the introduction of foreign substances into the caliper body, the push head comprising an axial end which carries a so-called receiving surface extending circumferentially around the longitudinal axis, the ring being fitted onto said receiving surface of the push head.

[0007] In one embodiment, the thrust head includes a shoulder configured to prevent a displacement of the ring relative to the thrust head in said first direction.

[0008] In one embodiment, the device includes a retaining piece configured to prevent movement of the ring relative to the push head in said second direction.

[0009] In one embodiment, the retaining piece is made from a metal plate.

[0010] In one embodiment, the retaining piece is fixed to the push head by one or more fixing elements, such as pins or screws.

[0011] In one embodiment, the retaining piece includes at least one so-called connecting element which is housed in one or more openings formed in the ring.

[0012] The aforementioned opening(s) may in particular be formed in a rear surface of the ring and surround at least partially the receiving surface.

[0013] In one embodiment, the aforementioned opening(s) include an opening such as a groove formed in the ring.

[0014] In one embodiment, the device includes a drive mechanism which is configured to be able to move the piston in translation along the longitudinal axis relative to the caliper body in said first direction and / or in said second direction.

[0015] In one embodiment, the drive mechanism comprises a first element and a second element cooperating with each other such that a rotation of the second element around the longitudinal axis causes a translation of the first element along the longitudinal axis.

[0016] In one embodiment, the first element of the drive mechanism is configured to bear axially on the thrust head so that a displacement of the first element of the drive mechanism in said first direction causes a displacement of the piston in said first direction.

[0017] In one embodiment, the movement of the first element of the drive mechanism in said first direction results from a rotation of the second element of the drive mechanism.

[0018] In one embodiment, said retaining piece includes one or more so-called drive elements which preferably extend radially inwards with respect to a body of the retaining piece.

[0019] In one embodiment, said first element of the drive mechanism is configured to bear axially on said drive elements of said retaining piece so that a displacement of the first element of the drive mechanism in said second direction causes a displacement of the piston in said second direction.

[0020] In one embodiment, the movement of the first element of the drive mechanism in said second direction results from a rotation of the second element of the drive mechanism.

[0021] In one embodiment, said retaining piece is configured to allow elastic deformation of said drive elements with respect to said body of this retaining piece under the action of a force exceeding a predetermined threshold exerted by the first element of the drive mechanism.

[0022] The invention also relates to a caliper brake comprising one or more braking devices as defined above.

[0023] The brake is preferably a floating or sliding caliper brake.

[0024] Preferably, the brake includes at least one electric actuator.

[0025] The invention also relates to a method for assembling a braking device as defined above.

[0026] The method preferably includes a step of mounting the ring on said receiving surface of the thrust head by moving the ring relative to the thrust head in said first direction along the longitudinal axis.

[0027] Among other advantages, the invention makes it possible to simplify the manufacture and assembly of the braking device and more generally of the brake.

[0028] The invention as defined in the claims can be implemented in braking devices and / or in brakes as described in the French patent applications filed on July 19, 2023 under numbers FR2307735 and FR2307736 and / or as described in the French patent application filed on February 23, 2024 under number FR2401802 and / or as described in the French patent application filed on March 15, 2024 under number FR2402613.

[0029] Other advantages and features of the invention will become apparent from the following detailed, non-limiting description. Brief description of the figures

[0030] The detailed description that follows refers to the attached drawings on which: - [Fig.1] is a schematic perspective view of a caliper brake comprising two braking devices according to the invention; - [Fig.2] is a schematic cross-sectional view of a braking device according to the invention, this device comprising a push head, a sealing ring and a retaining piece forming a piston, as well as a ball screw drive mechanism; - [Fig.3] is a schematic cross-sectional view of part of the device of [Fig.2], showing means of assembling the push head, the ring and the retaining piece; - [Fig.4] is a schematic perspective view of part of the device of [Fig.2], showing the thrust head as well as elastic elements housed in notches of the thrust head; - [Fig.5] is a schematic perspective view of part of the device of [Fig.2], showing the ring assembled with the retaining piece.

[0031] Common references are used on the different figures to designate identical or similar elements. Detailed description of implementation methods

[0032] Figures 1 to 5 include a reference frame defining orthogonal directions D1, D2 and D3.

[0033] Figure [Fig. 1] shows a brake 1 according to the invention.

[0034] By way of non-limiting agreement, brake 1 is a floating caliper brake intended to be connected to a wheel (not shown) of a motor vehicle (not shown) having an axis of rotation parallel to the direction Dl.

[0035] In this example, the brake caliper 1 comprises a solid cast iron body 2 forming bores 3 (only one bore 3 being visible in [Fig. 1]) intended to receive guide pins (not shown) in order to allow the caliper to be moved relative to a fixed structure (not shown) of the vehicle, in translation along the direction DL

[0036] The brake 1 of [Fig.1] comprises two sub-assemblies 5, also called "braking devices", which are housed in cavities formed by the body 2 of the caliper.

[0037] In this non-limiting example, each of the subassemblies 5 of the brake 1 of [Fig.1] includes a braking device similar to that described below with reference to Figures 2 to 5, which generally includes a piston 7 and a piston 7 drive mechanism 8 (see [Fig.2]).

[0038] In a manner known per se, the brake 1 of [Fig.1] is provided to move friction elements (not shown) against a disc (not shown) of the wheel, by translation of the pistons of the subassemblies 5 in a direction SI along the direction D1, relative to the body 2 of the caliper, and by translation of the caliper, via the columns, relative to said fixed structure of the vehicle in a direction S2 opposite to the direction SI, so as to exert a braking force on the disc.

[0039] In the non-limiting embodiment of Figures 2 to 5, the braking device 5 comprises: - said piston 7, - a shaft / screw 23 and a nut 24 forming a ball screw system with ball recirculation which forms said drive mechanism 8, - two springs 31 (cf. [Fig.4]).

[0040] Figure 2 shows the device 5 in an assembled configuration, in which it has a longitudinal axis Al around which its components extend. In this example, the axis Al is parallel to the direction DL

[0041] With reference to [Fig.2], the drive mechanism 8 in this example includes a part 160 fixed to one end of the shaft 23, called the "front end", by means of a screw 161.

[0042] Part 160 thus forms a head of the drive mechanism 8 integral with the shaft 23.

[0043] The part 160, also called the "drive head", has a surface 162 called the support surface which, in this example, is curved along the direction D3.

[0044] Axially opposite the bearing surface 162, the part 160 forms a groove receiving the front end of the shaft 23 so as to secure the part 160 with the shaft 23 with respect to rotation about the axis Al. The shaft 23 is movable in translation and fixed in rotation relative to the bracket.

[0045] In the non-limiting embodiment of figures 2 to 5, the piston 7 of the device 5 comprises an assembly of several components including a thrust head 33, a ring 34 and a retaining piece 165, as well as two fixing pins 166.

[0046] With reference to Figures 2 to 4, the thrust head 33 is generally in the form of a disk extending around the axis AL

[0047] The thrust head 33 includes surfaces 81 and 90 which axially delimit the thrust head 33 on either side (see [Fig.2]).

[0048] In this example, the surface 90 is intended to cooperate, in a manner known per se, with one of said friction elements of the brake.

[0049] With reference to [Fig.4], the surface 81 more specifically comprises a peripheral part 81A which is not limited to planar, in this case parallel to the directions D2 and D3, and a central part 81B which in this example is not limited to curved along the direction D3.

[0050] Surface 81 is called "support surface".

[0051] With further reference to [Fig. 4], the thrust head 33 also comprises two axial portions delimited radially on the outside by surfaces 170 and 171, respectively, each extending around the axis Al and which are in this case circular. The portion delimited by surface 170 has a smaller diameter than that delimited by surface 171.

[0052] In this example, the thrust head 33 includes a shoulder resulting in such a difference in diameter between the two aforementioned axial portions.

[0053] Said shoulder of the thrust head 33 forms in this example an annular surface 172 extending around the axis Al and along a plane parallel to the directions D2 and D3.

[0054] Surface 170 is called the "receiving surface".

[0055] The receiving surface 170 intersects in this example the peripheral part 81A of the surface 81 by forming an edge 173 which in this example is circular and parallel to the directions D2 and D3.

[0056] The receiving surface 170 is thus formed by a rear axial end of the thrust head 33, in particular the axial end opposite to that which is intended to cooperate with the friction element.

[0057] The thrust head 33 also includes two orifices 174 each opening onto the part 81A of the surface 81.

[0058] With reference to [Fig.3], the ring 34 of the device 5 in this example comprises a part 120 folded into a bellows as well as connecting ends 121 and 122, forming a piece which extends circumferentially around the axis Al.

[0059] In this example, the end 121 is a radially internal end of the ring 34 and the end 122 is a radially external end of the ring 34, the ends 121 and 122 being further spaced or axially spaceable from each other.

[0060] In this example, the end 121 has a radially internal circular surface 175 having a diameter substantially identical to that of the surface 170 of the thrust head 33.

[0061] The end 121 further includes a groove 176 which extends axially and concentrically with respect to the surface 175 (see [Fig.3]).

[0062] In this example, the ring 34 constitutes a "dust boot" type element, also called a "piston boot" in English or a "sealing ring", which, in a manner known per se, makes it possible in particular to prevent or limit the introduction of foreign substances, such as dust or debris, into the body 2 of the caliper.

[0063] By way of non-limitation, the ring 34 can be made of a material of the "Gore-Tex" type, or any other, also allowing elastic deformation of the bellows 120 during braking.

[0064] With reference to figures 2, 3 and 5, the retaining piece 165 of the device 5 is in the form of a generally flat and circular piece which extends around the axis Al and which has a central opening.

[0065] By way of non-limitation, the retaining piece 165 can be manufactured by machining and / or stamping a metal plate.

[0066] In this example, the retaining piece 165 includes a part 180 called "body" having two orifices 181 as well as parts or elements 182 and 183.

[0067] With reference to [Fig.5], the retaining piece 165 in this example comprises two elements 182 which are symmetrical with respect to each other with respect to a fictitious plane passing through the axis Al and parallel to the directions DI and D2.

[0068] Each of the elements 182 forms a leg which extends radially inwards relative to the body 180 of the retaining piece 165, defining a semi-circular radially internal edge which extends opposite the other element 182.

[0069] Said central opening of the retaining piece 165 is radially delimited by the edge of the elements 182.

[0070] The 182 elements are called "drive elements".

[0071] In this example, the retaining piece 165 is made so as to allow elastic deformation of the elements 182 relative to the body 180, in this case under the action of a force exerted along the DI direction on the elements 182 when this force exceeds a predetermined threshold, typically during an opening phase of the stirrup.

[0072] With reference to [Fig.3], the element 183 of the retaining piece 165, also called the "connecting element", forms in this example a radial end of the retaining piece 165 which extends at the right of the body 180, axially in the SI direction.

[0073] In this non-limiting example, the connecting element 183 has an overall annular geometry extending around the axis Al.

[0074] A non-limiting assembly method of these different components will now be described in order to place the device 5 in the configuration of [Fig.2].

[0075] With reference to Figures 3 and 5, the retaining piece 165 and the ring 34 are connected to each other so that the connecting element 183 of the retaining piece 165 is housed in the groove 176 of the ring 34, thus forming a first subassembly as illustrated in [Fig.5].

[0076] By way of non-limitation, the ring 34 can be overmolded onto the retaining piece 165.

[0077] With reference to [Fig. 2], the thrust head 33 and the shaft 23 equipped with the drive head 160 are arranged so that the surface 162 of the drive head 160 bears against, or is opposite, the central part of the bearing surface 81 of the thrust head 33, forming a second subassembly. In this example, the screw 161 comprises a head that extends into a cavity formed by the thrust head 33 and opens onto the central part of the surface 81 (see Figures 2 and 4).

[0078] Said first sub-assembly is then assembled with said second sub-assembly, by aligning these two sub-assemblies on the axis Al and moving them against each other so as to fit the end 121 of the ring 34 onto the rear end of the push head 33.

[0079] More specifically, the sub-assembly formed by the ring 34 and the retaining piece 165 is in this example moved in the direction of the thrust head 33 until the end 121 of the ring 34 comes into contact with the surface 172 of the shoulder of the thrust head 33 and the body 180 of the retaining piece 165 comes into contact with the peripheral part of the surface 81 of the thrust head 33, according to an angular orientation such that the orifices 181 of the retaining piece 165 are respectively aligned with the orifices 174 of the thrust head 33.

[0080] During this movement, the shaft 23 extends through the central opening of the retaining piece 165.

[0081] The fitting step described above is in this example carried out cold, i.e. at room temperature.

[0082] The pins 166 are then inserted into the orifices 174 of the push head by passing through the orifices 181 of the retaining piece 165, in order to maintain the aforementioned subassemblies in the configuration of [Fig.2].

[0083] In this configuration, the end 121 of the ring 34 is axially clamped between the shoulder of the push head 33 and the body 180 of the retaining piece 165 and, radially, between the connecting element 183 of the retaining piece 165 and the receiving surface 170 of the push head 33 (see [Fig.3]).

[0084] The end 121 of the ring 34 is thus secured to the thrust head 33, particularly in translation along the axis AL

[0085] In the configuration of [Fig.2], the drive head 160 of the drive mechanism 8 extends axially between the central part of the bearing surface 81 of the push head 33 and the drive elements 182 of the retaining piece 165.

[0086] In this embodiment, the springs 31, which in this example are spiral springs, are interposed radially between the drive head 160 of the drive mechanism 8 and notches in the push head 33 (see [Fig.4]), in order to be able to, on the one hand, dampen displacements of the push head 33 along the direction D2 around an equilibrium position relative to the shaft 23 in which it is centered on the axis Al and, on the other hand, return the push head 33 to the equilibrium position, in particular at the end of the braking phase.

[0087] The components thus assembled are then conventionally assembled with the nut 24 and with the other parts of the brake, in particular so that the end 122 of the ring 34 cooperates with a bore (not shown) of the caliper body to form a seal at least against dust, at least when the piston 7 is in a so-called rest configuration.

[0088] The device 5 is configured to allow a translation of the piston 7 and therefore of the thrust head 33 along the direction DI under the action of a rotation around the axis Al of the nut 24 of the drive mechanism 8.

[0089] To do this, the nut 24 is fixed in translation relative to the caliper and can be driven in rotation around the axis Al by a transmission element (not shown) which may include one or more toothed wheels.

[0090] In the particular example of [Fig. 1] in which the brake 1 comprises two braking devices 5 such as that described above, the transmission element can typically include a toothed wheel (not shown) passing through a lateral opening 152 in the body 2 of the caliper, so as to simultaneously drive the nuts 24 of the two devices 5 around the corresponding axis A1. Such a toothed wheel can be driven by an electric motor (not shown), for example via a transmission (not shown).

[0091] By way of non-limitation, brake 1 of [Fig.1] can be used as a service brake.

[0092] In operation, for each of the brake 1 devices 5, the piston 7 and the push head 33 are moved from said rest configuration illustrated in [Fig.1] to a deployed configuration (not shown) until the friction elements are in contact with the disc and then a braking force is applied.

[0093] During such a braking phase, for each of the devices 5, the surface 162 of the drive head 160 carried by the shaft 23 comes to rest on the central part of the bearing surface 81 of the push head 33 so that the displacement in the SI direction of the shaft 23 causes a corresponding displacement of the push head 33 and, consequently, of the ring 34 whose end 122 is housed and held in the corresponding bore of the body 2 of the caliper.

[0094] For illustrative purposes only, each of the devices 5 can be configured so that an input torque of approximately 33 Nm applied to the nut 24 of the drive mechanism 8 can produce a braking force of approximately 35 kN on the disc and, in reaction, a counter-braking force on a sensor (not shown) associated with this device 5.

[0095] Said sensor of each of the devices 5 can be connected to a computer (not shown) in order to transmit to it information, in the form of electrical signals, relating to the axial forces applied to the sensors.

[0096] Such a computer can be configured to control said electric motor and thus adapt the braking effort, and / or one or more other parameters such as torque or deceleration, according to this information and taking into account a braking instruction.

[0097] At the end of braking, each of the devices 5 of the brake 1 is returned to the rest configuration by reversing the direction of rotation of the motor.

[0098] In particular, for each of the devices 5, the drive head 160 of the shaft 23 comes to rest on the drive elements 182 of the retaining piece 165 so that the movement in the direction S2 of the shaft 23 causes a corresponding movement of the retaining piece 165 and therefore of the piston 7.

[0099] Such a brake 1 can also be used in a similar way as a parking brake.

[0100] The preceding description is by no means exhaustive. Among other variations, the braking device 5 described above may have a different architecture and / or parts that are arranged differently and / or that have different geometric and / or dimensional and / or material characteristics.

[0101] By way of non-limitation, the drive mechanism 8 of the device of the invention may generally comprise a first element and a second element which cooperate with each other such that a rotation of the second element around the longitudinal axis causes a translation of the first element along the longitudinal axis. In the embodiment of [Fig. 2], the first element is formed by the shaft 23 and the second element is formed by the nut 24. In an alternative embodiment not shown, the first element may conversely be the nut and the second element the shaft of a similar ball screw system. Furthermore, the device of the invention may include a drive mechanism other than a ball screw system.

[0102] In an alternative embodiment, not shown, the movement of the piston 7 in the direction S2 can be achieved by driving not the retaining piece 165 but one or more other pieces integral with, or formed by, the thrust head 33.

[0103] Of course, when the braking device includes a retaining piece 165 as described above, this can be fixed to the push head 33 and / or to the ring 34 by fixing members other than the pins 166, for example screws or by cooperation of complementary surfaces respectively formed by the retaining piece and / or the push head and / or the ring.

[0104] For other examples, said receiving surface of the thrust head and the surface of the ring cooperating with it may have a non-circular geometry, for example a polygonal geometry.

[0105] According to another embodiment, not shown, the radially external end of the retaining piece can extend in a radial direction with respect to the axis Al, in contrast to part 183 of part 165 of [Fig. 3] which extends along the axis Al. Such an end can of course be housed in a radial groove of the ring 34. More generally, the retaining piece can comprise one or more elements cooperating with one or more openings in the ring in order to secure these parts to each other.

[0106] Furthermore, the device of the invention can be configured to produce a clamping force different from that indicated above, for example a maximum braking force of 25 kN, or 35 kN, or 45 kN, or even 65 kN.

[0107] The invention also covers a brake comprising one or more braking devices 5 according to the invention.

[0108] In one embodiment, not shown, the brake includes a high-efficiency reversible geared motor, associated with a brake parking locking mechanism in a braking position.

[0109] List of reference numbers: - 1: Caliper brake - 2: Stirrup body - 3: Bore of the caliper body - 5: Braking device 7: Piston 8: Drive Mechanism 23: Shaft / screw (ball screw system, drive mechanism) 24: Nut (ball screw system, drive mechanism) 31: Spring 33: Push head (piston) 34: Ring (piston) 81, 90, 170-172: Thrust head surface 120: Bellows-like section of the ring 121, 122: End of the ring 152: Opening of the stirrup body 160: Drive head (ball screw system, drive mechanism) 161: Fixing screw (ball screw system, drive mechanism) 162: Bearing surface of the drive shaft head (ball screw system, drive mechanism) 165: Retaining part (piston) 166: Fastening element (piston) 173: Edge of the thrust head 174: Thrust head orifice 175: Ring surface 176: Ring Throat 180: Body of the retaining piece 181: Retaining piece orifice 182, 183: Part of the retaining piece Al: Longitudinal axis DI: Axial / longitudinal direction (reference frame) D2, D3: Transverse direction (reference frame) SI, S2: Direction of movement

Claims

Demands

1. Braking device (5) for caliper brake (1), comprising a piston (7) provided to be moved relative to a caliper body (2) in translation along a longitudinal axis (Al1) selectively in a first braking direction (S1) and in a second direction (S2) opposite to the first direction (S1), the piston (7) comprising a push head (33) and a ring (34) intended to prevent or limit the introduction of foreign substances into the caliper body (2), the push head (33) comprising an axial end which carries a receiving surface (170) extending circumferentially around the longitudinal axis (Al1), the ring (34) being fitted onto said receiving surface (170) of the push head (33).

2. Device (5) according to claim 1, wherein the push head (33) includes a shoulder (172) configured to prevent displacement of the ring (34) relative to the push head (33) in said first direction (SI).

3. Device (5) according to claim 1 or 2, comprising a retaining piece (165) configured to prevent movement of the ring (34) relative to the push head (33) in said second direction (S2), the retaining piece (165) preferably being made from a metal plate.

4. Device (5) according to claim 3, wherein the retaining piece (165) is fixed to the push head (33) by one or more fasteners (166), such as pins or screws.

5. Device (5) according to claim 3 or 4, wherein the retaining piece (165) comprises at least one connecting element (183) which is housed in one or more openings (176) formed in a rear surface of the ring (34) and at least partially surrounding the receiving surface (170), such as a groove formed in the ring (34).

6. Device (5) according to any one of claims 1 to 5, comprising a drive mechanism (8) configured to move the piston (7) in translation about the longitudinal axis (A1) relative to the caliper body (2) in said first direction (A1) and / or in said second direction (A2), the drive mechanism (8) comprising a first element (23) and a second element (24) cooperating with each other so that a rotation of the second element (24) around the longitudinal axis (Al) causes a translation of the first element (23) along the longitudinal axis (Al).

7. Device (5) according to claim 6, wherein the first element (23) of the drive mechanism is configured to bear axially on the thrust head (33) such that a displacement of the first element (23) of the drive mechanism (8) in said first direction (SI) causes a displacement of the piston (7) in said first direction (SI), the displacement of the first element (23) of the drive mechanism (8) in said first direction (SI) preferably resulting from a rotation of the second element (24) of the drive mechanism (8).

8. Device (5) according to claim 6 or 7 incorporating the retaining piece (165) according to claim 3, wherein: - the retaining piece (165) comprises one or more drive elements (182) which preferably extend radially inwards relative to a body (180) of the retaining piece (165), - said first element (23) of the drive mechanism (8) is configured to bear axially on said drive elements (182) of the retaining piece (165) such that a displacement of the first element (23) of the drive mechanism (8) in said second direction (S2) causes a displacement of the piston (7) in said second direction (S2), the displacement of the first element (23) of the drive mechanism (8) in said second direction (S2) preferably resulting from a rotation of the second element (24) of the drive mechanism (8),- the retaining piece (165) is optionally configured to allow elastic deformation of said drive elements (182) relative to said body (180) of this retaining piece (165) under the action of a force exceeding a predetermined threshold exerted by the first element (23) of the drive mechanism (8).

9. Caliper brake (1), preferably floating or sliding, comprising one or more braking devices (5) according to any one of claims 1 to 8.

10. Method of assembling a braking device (5) according to any one of claims 1 to 8, comprising a step of mounting the ring (34) on said receiving surface (170) of the push head (33) by moving the ring (34) relative to the push head (33) in said first direction (SI) along the longitudinal axis (Al).

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