Braking feel simulator

Abstract

The present invention relates to a dry braking feel simulator (1) comprising a cylinder (3) defining a simulator chamber ( 3 ); wherein the simulator chamber (3) is hydraulically isolated, for example the cylinder (3) has no openings or connection routes configured to connect fluidly the simulator chamber (3) to another component; a float or piston (4) movably housed in the simulator chamber (3) between a rest position (XO) and a stroke end position (Xm) along an axial direction (X-X), the piston (4) being adapted to be connected to a lever (5) operable by a user, such as a brake pedal, for example, a reaction assembly (6) configured to elastically oppose an advancement of the piston (4) from the rest position (XO) towards the stroke end position (Xm), the reaction assembly (6) being configured to dampen the advancement of the piston (4), wherein, under an external thrust force, for example by the user, the piston (4) is configured to advance towards the stroke end position (Xm) in opposition to a reaction force generated by the reaction assembly (6); wherein when the thrust action ceases, the reaction assembly (6) is configured to bias the piston (4) towards the rest position (XO); wherein the reaction assembly (6) is housed in the simulator chamber (3) and is interposed between a cylinder portion (7) and the piston ( 4 ); at least one sensor (8) configured to detect, either directly or indirectly, a current position (X) of the piston (4) between the rest position (XO) and the stroke end position (Xm); wherein the reaction assembly (6) comprises at least one elastomeric spring (9), avoiding the inclusion of porous elastomeric damping elements and / or compression springs in series with the elastomeric spring (9), wherein the elastomeric spring (9) is configured to generate the reaction force on the piston (4) for any advancement of the piston (4) between the rest position (XO) and the stroke end position (Xm), damping the advancement of the piston (4) and, when the thrust force ceases, elastically biasing the piston (4) towards the rest position (XO).

Description

"Braking feel simulator”DESCRIPTION

[0001] . Field of the invention

[0002] . The present invention relates to a braking feel simulator, e . g . , a pedal feel simulator or pedal simulator, and to a braking system of the Brake-by-Wire type .

[0003] . Background art

[0004] . Vehicles with two or more wheels comprise a braking system controlled by a driver by means of a lever or pedal . By pressing the brake pedal along a pedal stroke , the driver feels a generated reaction force which provides the driver with the so-called " feel" of the brake pedal . Based on this brake pedal feel , the driver can perceive a feeling of braking .

[0005] . The pedal is characterized by a sti ffness , which defines the reaction force provided to the driver, and therefore comfort and driving safety depend on the definition of the pedal stiffness .

[0006] . In the hydraulic braking systems , the pedal stif fness depends on the elastic reaction forces of elastic elements , such as helical springs , for example, on the damping forces , due for example to the hydraulic fluid in the brake master cylinder and in the brake master cylinder connection routes towards the braking devices , and on frictional forces between the movable components of the braking system.

[0007] . In braking systems of the Brake-by-Wire (BBW) type for vehicles with two or more wheels operable by a driver by means of abrake pedal or lever, the force and displacement imparted to the brake pedal or lever by the driver are decoupled from the resulting braking force, which is applied by at least one braking device to the respective wheel of the vehicle . In BBW braking systems , the force and displacement applied by the driver to the brake pedal or lever are transduced into an electrical signal , which is processed by a control unit to control the actuation of the braking devices of the braking system .

[0008] . Accordingly, it is known to equip the BBW braking systems with a braking feel simulator device connectable to the brake pedal or lever and configured to simulate the feel and sti ffness of a brake pedal or lever of conventional hydraulic braking systems , and thus emulate the " stif fness curve" thereof .

[0009] . Stif fness curve" means the relationship between the displacement of the brake pedal or lever along its stroke and the respective reaction force applied by the simulator device to the brake pedal or lever, and thus by the brake pedal or lever to the driver .

[0010] . Some pedal feeling simulators involve the presence of helical springs in series with hydraulic absorbers , which require hydraulic fluid containment chambers .

[0011] . The presence of hydraulic fluid inside the pedal simulator makes it necessary to ensure a volume to contain it and compensate for the thermal volume variability thereof , increasing the size of the pedal simulator and making it necessary to fill and manage the hydraulic fluid in the production line .

[0012] . Additionally, the co-presence of springs and hydraulic fluid increases the overall size of the pedal simulator .

[0013] . Other pedal feel simulators are dry pedal feel simulators , i . e . , free from hydraulic fluid . From document EP1526050 it is known to manufacture dry pedal simulators which comprise a damping element made of elastomeric foam in series with one or more elastic elements , such as one or more helical springs . However, the provision of multiple damping and elastic elements in series makes it necessary to provide containment volumes as well as connection systems between the elements which make the pedal feel simulator cumbersome, and the high number of components makes assembly and maintenance expensive . Additionally, the elastomeric foam elements are subj ect to accelerated wear, changing their viscoelastic characteristics over time .

[0014] . Therefore, in the industry the need is felt for compact and space-saving braking feel simulators , which are also less structurally complex than those known .

[0015] . Moreover, in the industry the need is felt for braking feel simulators which comprise fewer components than those known and which involve fewer and simplified mechanical machining steps for the housings , assembly steps , and end-of-line check .

[0016] . Solut ion

[0017] . The present invention aims to provide a braking feel simulator, which allows obviating at least some of the drawbacks highlighted in the prior art .

[0018] . These and other obj ects are achieved by a dry braking feelsimulator and a Brake-by-Wire braking system according to the independent claims .

[0019] . Some advantageous embodiments are the subj ect of the dependent claims .

[0020] . By virtue of the suggested solutions , it is possible to provide a dry braking feel simulator which is more compact and adapted to be installed inside the vehicle passenger compartment .

[0021] . By virtue of the suggested solutions , it is possible to provide a dry braking feel simulator with fewer components .

[0022] . By virtue of the suggested solutions , it is possible to provide a dry braking feel simulator which is reliable and resistant to wear .

[0023] . By virtue of the suggested solutions , it is possible to provide a dry braking feel simulator and a braking system, which have low costs , lower maintenance requirements , lower machining complexity, simpli fied assembly, as well as simpli fied end-of-line testing .

[0024] . Figures

[0025] . Further features and advantages of the dry braking feel simulator will be apparent from the following description of preferred embodiments thereof , given by way of non-limiting indication, with reference to the accompanying drawings , in which :

[0026] . - figure 1 is an axonometric view of a braking feel simulator according to the present invention;

[0027] . - figure 2 is a section side view with respect to a section plane passing through the axial direction of the brakingfeel simulator in figure 1 , according to a first embodiment ;

[0028] . - figure 3 is an exploded axonometric view of the braking feel simulator in figure 2 , in which the elastomeric spring is a hollowed elastomeric spring, for example ;

[0029] . - figure 4 shows a section side view with respect to a section plane passing through the axial direction of the braking feel simulator in figure 1 , according to a second embodiment ;

[0030] . - figure 5 is an exploded axonometric view of the braking feel simulator in figure 4 ;

[0031] . - figure 6 is a section side view with respect to a section plane passing through the axial direction of the braking feel simulator in figure 1 , according to a third embodiment ;

[0032] . - figure 7 is an exploded axonometric view of the braking feel simulator in figure 6 ;

[0033] . - figure 8 shows a section side view with respect to a section plane passing through the axial direction of the braking feel simulator in figure 1 , according to a fourth embodiment ;

[0034] . - figure 9 is an exploded axonometric view of the braking feel simulator in figure 8 ;

[0035] . - figure 10 is an axonometric view of an elastomeric spring of the braking feel simulator in figures from 6 to 9 , which can have an axial through cavity;

[0036] . - figure 11 is a plan view of the elastomeric spring in figure 10 ;

[0037] . figure 12 diagrammatically shows a braking feel simulator according to the present invention;

[0038] . - figure 13 shows features of the simulator of a braking feel obtained from a dry braking feel simulator according to the present invention, employing dif ferent reaction assemblies comprising the elastomeric spring according to di fferent geometries alone and / or in parallel with a compression spring;

[0039] . figure 14 separately shows the stif fness of the di fferent elastomeric spring geometries and the stif fness of the compression spring used in some embodiments of the braking feel simulator ;

[0040] . - figure 15 diagrammatically shows a braking system according to the present invention .

[0041] . Description of some preferred embodiments

[0042] . According to a general embodiment , a dry braking feel simulator or dry pedal simulator is indicated by reference numeral 1 .

[0043] . Said dry braking feel simulator 1 comprises a cylinder 2 defining a simulator chamber 3 . In an embodiment, the simulator chamber 3 is dry, i . e . , hydraulically isolated . For example, the cylinder 2 is free from openings or connection routes configured to connect the simulator chamber 3 hydraulically to the outside of the cylinder and / or to hydraulic connection routes . In an embodiment, the simulator chamber 3 is cylindrical .

[0044] . Said dry braking feel simulator 1 comprises a float or piston 4 . The piston 4 is housed in a movable manner in the simulator chamber 3 between a rest position XO and a stroke end position Xm along an axial direction X-X . The piston 4 is configuredto be connected to a lever 5 operable by a user, such as a brake pedal or a grippable brake lever, for example . Brake pedal or lever means a hand-operated device adapted to actuate the pedal simulator 1 .

[0045] . Said dry braking feel simulator 1 comprises a reaction assembly 6, which is configured to oppose elastically, and / or viscoelastically, an advancement of the piston 4 from the rest position XO towards the stroke end position Xm.

[0046] . The reaction assembly 6 is configured to dampen a forward movement of the piston 4 towards the stroke end position Xm . In an embodiment, the reaction assembly 6 i s configured to dampen a movement of the piston 4 and / or a retraction towards the rest position XO .

[0047] . Under an external thrust force, e . g . , by the user, the piston 4 is configured to advance towards the stroke end position Xm in opposition to a reaction force generated by the reaction assembly 6.

[0048] . When the thrust action ceases , the reaction assembly 6 is configured to bias the piston 4 towards the rest position XO and maintain the piston 4 in the rest position XO , in the absence of external thrust actions .

[0049] . Said dry braking feel simulator 1 comprises at least one sensor 8 configured to detect , either directly or indirectly, a current position X of the piston 4 between the rest position XO and the stroke end position Xm .

[0050] . Advantageously, the reaction assembly 6 comprises at leastone elastomeric spring 9 , avoiding the inclusion of porous elastomeric damping elements and / or compression springs in series with the elastomeric spring 9 .

[0051] . The elastomeric spring 9 is configured to generate the reaction force on the piston 4 for any advancement of the piston 4 between the rest position XO and the stroke end position Xm, damping the advancement of the piston 4 , and when the thrust force ceases , elastically biasing the piston 4 towards the rest position XO . In an embodiment, the elastomeric spring 9 is configured to maintain the piston 4 in the rest position XO in the absence of external thrust forces . In an embodiment , the elastomeric spring 9 is configured to dampen a retraction of the piston 4 towards the rest position XO .

[0052] . In an embodiment, the reaction assembly 6 comprises a compression spring 10 .

[0053] . In an embodiment , the elastomeric spring 9 and the compression spring 10 are arranged in parallel .

[0054] . In an embodiment , the compression spring 10 is configured to generate a redundant reaction force with respect to the reaction force generated by the elastomeric spring 9.

[0055] . In an embodiment, the cylinder 2 defines the simulator cavity 5 with its peripheral walls , such as a cylinder side wall and two opposite cylinder bottom walls . In an embodiment , the simulator cavity 5 extends along a thrust direction X-X, which rectilinear direction defines an axis about which the cylinder side wall extends in parallel .

[0056] . In an embodiment , when the piston 4 is in the restposition XO , the elastomeric spring 9 has an axial elastomeric spring extension at rest XI and the compression spring 10 has an axial compression spring extension at rest X2 .

[0057] . In an embodiment, the axial compression spring extension at rest X2 is less than the axial elastomeric spring extension at rest XI .

[0058] . In an embodiment, the elastomeric spring 9 is free from elastic inserts and / or is made in one piece of solid, non-porous elastomeric material .

[0059] . In an embodiment, the elastomeric spring 9 is made of EPDM (Ethylene-Propylene Diene Monomer) , Teflon ( PTFE Polytetrafluoroethylene ) , NBR (Nitrile Rubber) , HNBR (Hydrogenated Nitrile Rubber) , non-porous polyurethane .

[0060] . In an embodiment, the compression spring 10 is a helical spring . In an embodiment , the compression spring 10 is made of spring steel .

[0061] . In an embodiment, the elastomeric spring 9 has an elastomeric spring stiffness R1 . According to an embodiment , the elastomeric spring sti ffness R1 is between 40 N / mm and 200 N / mm, preferably between 80 N / mm and 120 N / mm, even more preferably is of about 100 N / mm.

[0062] . In an embodiment, the compression spring 10 comprises a compression spring stiffness R2 . According to an embodiment , the compression spring sti ffness R2 is between 0 . 5 N / mm to 10 N / mm, preferably between 1 N / mm and 5 N / mm, preferably is of about 4 N / mm.

[0063] . In an embodiment, the compression spring stiffness R2 islower than the elastomeric spring sti ffness R1 by at least one order of magnitude . In an embodiment , the compression spring stiffness R2 is lower than the elastomeric spring stif fness R1 by about two orders of magnitude .

[0064] . In an embodiment, the compression spring 10 has a linear elastic characteristic .

[0065] . In an embodiment, the elastomeric spring 9 has a nonlinear elastic characteristic .

[0066] . In an embodiment, said elastomeric spring 9 comprises a spring body 11 . In an embodiment, the spring body 11 comprises a head wall 12 and a tail wall 13 , and the spring body 11 extends or runs along an axial direction X-X between the head wall 12 and the tail wall 13 . The spring body 11 comprises a side wall 14 which connects the head wall 12 and the tail wall 13 .

[0067] . In an embodiment, the tail wall 13 abuts against a cylinder wall 15 of the cylinder portion 7 .

[0068] . In an embodiment, the head wall 12 abuts against the piston 4 .

[0069] . In an embodiment, the tail wall 13 has a tail abutment surface and the head wall 12 has a head abutment surface, where the head abutment surface has a surface area at least equal to the surface area of the tail abutment surface . In an embodiment, the tail abutment surface and the head abutment surface are planar surfaces perpendicular to the axial direction X-X .

[0070] . According to an embodiment, the side wall 14 is parallel to the axial direction X-X, where the spring body 11 is cylindrical .

[0071] . In an embodiment , the side wall 14 is corrugated comprising a plurality of first circumferential portions 16, coaxial to the axial direction X-X, interspersed by a plurality of second circumferential portions 17 , coaxial to the axial direction X-X, where the second annular portions 17 form a radial narrowing in the spring body 11 with respect to the first annular portions 16, which form a widening in the spring body 11 instead . .

[0072] . In an embodiment, the first circumferential portions 16 are toroidal portions .

[0073] . In an embodiment, the second circumferential portions 17 are discoidal or cylindrical portions .

[0074] . In an embodiment, considering a section of the spring body 11 in a plane comprising the axial direction X-X, the first circumferential portions and the second circumferential portions define the side wall as a ridge-and- valley structure, where the apex of the ridges is on the first circumferential portions and the minimum of the valleys is on the second circumferential portions .

[0075] . In an embodiment, the spring body 11 comprises a first tapered portion 18 and / or a second tapered portion 19 and a central portion 20 .

[0076] . In an embodiment, the first tapered portion 18 is preferably substantially f rustoconical in shape .

[0077] . In an embodiment , the second tapered portion 19 is preferably substantially f rustoconical in shape .

[0078] . In an embodiment, the central portion 20 is preferably cylindrical .

[0079] . In an embodiment, the first tapered portion 18 extends from the central portion, tapering away from the central portion 20 .

[0080] . In an embodiment, the second tapered portion 19 extend from the central portion 20 , tapering away from the central portion 20 .

[0081] . In an embodiment, the first tapered portion 18 and the second tapered portion 19 extend from the central portion 20 from opposite sides , tapering away from the central portion 20 .

[0082] . In an embodiment, the spring body 11 comprises a plurality of axial outlets 21 which mainly extend along respective outlet directions parallel to the axial direction X-X, circumferentially interspersed with a plurality of relief portions 22 on the side wall with respect to the axial outlets 21 .

[0083] . In an embodiment , the axial outlets 21 , and therefore the relief portions 22 , extend from the central portion 20 at least partially over the first tapered portion 18 and the second tapered portion 19.

[0084] . In an embodiment, the central portion 20 comprises a plurality of protuberances or fins 23 . In an embodiment, the protuberances or fins 23 extend radially outside the spring body 11 from at least one of the relief portions 22 of the side wall .

[0085] . In an embodiment, the spring body 11 delimits an axial cavity 24 along the axial direction X-X passing through the tail wall 13 and the head wall 12 .

[0086] . In an embodiment, the compression spring 10 is housed atleast partially in said axial cavity 24 interposing itself either directly or indirectly between the cylinder wall 15 and the piston 4 .

[0087] . In an embodiment, the compression spring 10 defines an internal cavity which extends along the axial direction X-X, where the elastomeric spring 9 , for example free from the axial cavity 24 , is housed at least partially within the internal cavity . The inner cavity of the compression spring 10 is delimited by the coils of the wire body of the helical spring .

[0088] . In an embodiment , the dry braking feel simulator 1 comprises a guide pin 25 at least partially housed in said axial cavity 24 . In an embodiment, the guide pin 25 has a first pin end 32 which is fixed to the cylinder 2 or to the float 4 . In an embodiment, the guide pin 25 has a second pin end 33 configured to connect to one end of the compression spring 10 .

[0089] . In an embodiment, said compression spring 10 is interposed between said guide pin 25 and said piston 4 or said guide pin 25 is interposed between said compression spring 10 and said piston 4 .

[0090] . In an embodiment , the dry braking feel simulator 1 comprises a brake pedal or brake lever 5 operatively connected to the piston 4 , preferably by means of a mechanical connection so that an actuation force applied by a driver or user to the brake pedal 101 is mechanically transferred to the piston 4 and the reaction assembly 6.

[0091] . In an embodiment, the dry braking feel simulator 1comprises a push rod or connection rod 26 adapted to connect the lever or pedal 5 to the piston 4 .

[0092] . In an embodiment, the push rod 26 is connected to the piston 4 by means of an attachment element . For example, the attachment element is a ball j oint 27 adapted to clamp a spherical or ball-like end of the push rod 26 .

[0093] . In an embodiment , the at least one sensor 8 is configured to detect an actuation and / or movement of the piston 4 . According to an embodiment , the at least one sensor is a position sensor or a pressure sensor or a force sensor or a combination thereof . According to an embodiment, the at least one sensor is a laser position sensor or an infrared position sensor or an elastomeric sensor or a piezoelectric sensor or a Hall effect sensor or a magnetoresistive sensor or a linear magnetic sensor or a combination thereof . According to an embodiment, the at least one sensor is positioned inside the cylinder 2 . In an embodiment , the sensor comprises a first sensor portion 30 and a second sensor portion 31 . In an embodiment, the first sensor portion 30 is connected in a fixed manner to the piston 4 , and the second sensor portion 31 is connected to the cylinder 2 , for example outside the simulator cavity 3 so as to detect the position of the first sensor portion 30 which is integral in motion with the piston 4 . In an embodiment, the second sensor portion 31 has an input port for connecting a data transmission cable . According to an embodiment, the second sensor portion is configured to detect the position of the first sensorportion .

[0094] . The present invention also relates to a braking system of the Brake-by-Wire type for a vehicle, comprising a dry braking feel simulator 1 according to any one of the previously described embodiments .

[0095] . The braking system further comprises at least one braking device 34 , such as a brake caliper, for example , and a control unit 35 operatively connected to the sensor 8 and the braking device 34 to control an actuation of said braking device 34 .LIST OF REFERENCE SIGNS dry braking feel simulator cylinder simulator chamber float or piston lever reaction assembly cylinder portion sensor elastomeric spring compression spring spring body head wall tail wall side wall cylinder wall first circumferential portions second circumferential portions first tapered portion second tapered portion central portion plurality of axial outlets plurality of relief portions fins or protuberances axial cavity guide pin push rod ball j oint ball portion seat partially spherical push rod end first sensor portion second sensor portion first pin end second pin end34 braking device35 control unitXO rest position XM stroke end positionXI axial elastomeric spring extension at restX2 axial compression spring extension at restR1 elastomeric spring sti ffnessR2 compression spring sti ffness

Claims

CLAIMS1. A dry braking feel simulator (1) comprising: a cylinder (2) defining a simulator chamber (3) ; wherein the simulator chamber (3) is hydraulically isolated, for example the cylinder (2) has no openings or connection routes configured to connect fluidly the simulator chamber (3) to another component; a float or piston (4) movably housed in the simulator chamber (3) between a rest position (X0) and a stroke end position (Xm) along an axial direction (X-X) , the piston (4) being adapted to be connected to a lever (5) operable by a user, such as a brake pedal, for example, a reaction assembly (6) configured to elastically oppose an advancement of the piston (4) from the rest position (X0) towards the stroke end position (Xm) , the reaction assembly (6) being configured to dampen the advancement of the piston (4) , wherein, under an external thrust force, for example by the user, the piston (4) is configured to advance towards the stroke end position (Xm) in opposition to a reaction force generated by the reaction assembly (6) ; wherein when the thrust action ceases, the reaction assembly (6) is configured to bias the piston (4) towards the rest position (X0) ; wherein the reaction assembly (6) is housed in the simulator chamber(3) and is interposed between a cylinder portion (7) and the piston(4) ; at least one sensor (8) configured to detect, either directly or indirectly, a current position (X) of the piston (4) between therest position (X0) and the stroke end position (Xm) ; characterized in that the reaction assembly (6) comprises at least one elastomeric spring (9) , avoiding the inclusion of porous elastomeric damping elements and / or compression springs in series with the elastomeric spring(9) , wherein the elastomeric spring (9) is configured to generate the reaction force on the piston (4) for any advancement of the piston (4) between the rest position (X0) and the stroke end position (Xm) , damping the advancement of the piston (4) and, when the thrust force ceases, elastically biasing the piston (4) towards the rest position (X0) .

2. A dry braking feel simulator (1) according to the preceding claim, wherein the reaction assembly 6) comprises a compression spring(10) , wherein the elastomeric spring (9) and the compression spring (10) are arranged in parallel, wherein the compression spring (10) is configured to generate a redundant reaction force with respect to the reaction force generated by the elastomeric spring (9) .

3. A dry braking feel simulator (1) according to the preceding claim, wherein, when the piston (4) is in the rest position (X0) , the elastomeric spring (9) has an axial elastomeric spring extension at rest (XI) and the compression spring (10) has an axialcompression spring extension at rest (X2) , wherein the axial compression spring extension at rest (X2) is less than the axial elastomeric spring extension at rest (XI) .

4. A dry braking feel simulator (1) according to any one of the preceding claims 2 to 3, wherein the elastomeric spring (9) has an elastomeric spring stiffness (R1 ) , wherein the compression spring (10) comprises a compression spring stiffness (R2 ) , wherein the compression spring stiffness (R2) is lower than the elastomeric spring stiffness (Rl) by at least one order of magnitude, preferably about two orders of magnitude, and / or wherein the compression spring (10) has a linear elastic characteristic, wherein the elastomeric spring (9) has a non-linear elastic characteristic .

5. A dry braking feel simulator (1) according to any one of the preceding claims, wherein the elastomeric spring (9) comprises a spring body (11) extending along an axial direction (X-X) between a head wall (12) and a tail wall (13) , wherein the tail wall (13) abuts against a cylinder wall (15) of the cylinder portion (7) , and / or wherein the head wall (12) abuts against the piston (4) , wherein the spring body (11) comprises a side wall (14) connectingthe head wall (12) and the tail wall (13) .

6. A dry braking feel simulator (1) according to the preceding claim, wherein the tail wall (13) has a tail abutment surface and the head wall (12) has a head abutment surface, wherein the head abutment surface is at least equal to the tail abutment surface, and / or wherein the tail abutment surface and the head abutment surface are planar surfaces perpendicular to the axial direction (X- X) .

7. A dry braking feel simulator (1) according to any one of the preceding claims 5 to 6, wherein the side wall (14) is parallel to the axial direction (X-X) , wherein the spring body (11) is cylindrical; or wherein the side wall (14) is corrugated comprising a plurality of first annular portions (16) , preferably toroidal in shape, coaxial to the axial direction (X-X) , interspersed by a plurality of second annular portions (17) , preferably discoidal or cylindrical in shape, coaxial to the axial direction (X-X) , wherein the second annular portions (17) form a radial narrowing with respect to the first annular portions (16) .

8. A dry braking feel simulator (1) according to any one of claims 5 to 6, wherein the spring body (11) comprises a first tapered portion (18) , preferably substantially f rustoconical in shape, a second tapered portion (19) , preferably substantiallyf rustoconical in shape, a central portion (20) , preferably substantially cylindrical in shape, wherein the first tapered portion (18) and the second tapered portion (19) extend from the central portion (20) from opposite sides, tapering away from the central portion (20) .

9. A dry braking feel simulator (1) according to the preceding claim, wherein the spring body (11) comprises a plurality of axial outlets (21) extending from the central portion (20) at least partially over the first tapered portion (18) and the second tapered portion (19) , radially forming a plurality of relief portions (22) .

10. A dry braking feel simulator (1) according to any one of the preceding claims 8 to 9, wherein the central portion (20) comprises a plurality of protuberances or fins (23) .

11. A dry braking feel simulator (1) according to claim 2 and any one of the preceding claims 5 to 10, wherein the spring body (11) delimits an axial cavity (24) along the axial direction (X-X) passing through the tail wall (13) and the head wall (12) ; wherein the compression spring (10) is housed at least partially in said axial cavity (24) interposing itself either directly or indirectly between the cylinder wall (15) and the piston (4) .

12. A dry braking feel simulator (1) according to the preceding claim, comprising a guide pin (25) at least partially housed in said axial cavity (24) ,wherein said compression spring (10) is interposed between said guide pin (25) and said piston (4) or wherein said guide pin (25) is interposed between said compression spring (10) and said piston (4) .

13. A dry braking feel simulator (1) according to any one of the preceding claims, comprising a push rod (26) adapted to connect the lever or pedal (5) to the piston (4) , wherein the push rod (26) is connected to the piston (4) with a ball joint ( 27 ) , wherein on the side axially opposite to the elastomeric spring (9) , the piston comprises a ball portion seat (28) to house a partially spherical push rod end (29) of the push rod (26) ; and / or wherein the dry braking feel simulator (1) comprises said lever (5) connected to the piston (4) by means of the push rod (26) .

14. A braking system of the brake-by-wire type for a vehicle, comprising- a dry braking feel simulator (1) according to any one of the preceding claims,- at least one braking device (34) ,- a control unit (35) operatively connected to the sensor (8) and the braking device (34) to control an actuation of said braking device ( 34 ) .

Images