Pressure simulator device for brake-by-wire braking system for vehicles

Abstract

A pressure simulator device for a brake-by-wire braking system for vehicles comprises an absorber body (10) with an absorber chamber (14) containing hydraulic fluid, a first fluid connection (4) for the exchange of hydraulic fluid between the absorber chamber (14) and a fluid reservoir (1), a plunger (5) urged by a manual actuation device (2), a movable component (8) sliding in the absorber chamber (14) along a main direction (X) and connected to the plunger (5) by means of a first elastic element (6), a second elastic element (7) fixed to the absorber body (10) and to the movable component (8) to counteract the movement of the movable component (8) in a first sliding direction (X1), and a blocking mechanism (80) to limit the sliding of the movable component (8) in the first sliding direction (X1) upon reaching a predetermined position.

Description

"PRESSURE SIMULATOR DEVICE FOR BRAKE -BY -WIRE BRAKINGSYSTEM FOR VEHICLES" DESCRIPTIONFIELD OF APPLICATION

[0001] The present invention relates to a brake-by-wire braking system for vehicles , in particular to a pressure simulator device for a brake-by-wire braking system and to a brake-by-wire braking system . PRIOR ART

[0002] Brake-by-wire braking systems currently available for vehicles , and in particular for motorcycles , are composed of three main subassemblies : the driver control , a feedback system, and an actuation system . The driver control , consisting of a lever or a pedal , is connected to a component that acts on the hydraulic fluid . The feedback system receives the hydraulic fluid and provides resistance feedback to the driver via a spring system . The actuation system, connected to the mechanical components that perform the braking action, moves the hydraulic fluid, for example by converting the rotary motion of an electric motor into linear motion to move the hydraulic fluid .

[0003] In brake-by-wire braking systems , the actuation system is general ly electrically connected to the rest ofthe braking system, but not hydraulically . This means that the force exerted by the driver on the lever or pedal is converted into an electrical signal via pressure , force or stroke transducers . This signal is then processed by a control unit that controls the actuators of the braking system . Since the two systems are separate , the brake master cylinder is replaced by a pump simulator, also called an absorber, i . e . , a device that simulates the feeling and sti f fness perceived by a driver when pressing the brake control in a conventional hydraulic braking system .

[0004] These systems have several drawbacks . One of the main drawbacks is the large number of components distributed in three distinct subassemblies , which result in signi ficant bulk and added weight . This is particularly problematic for motorcycles , where the available space is limited and low weight is a fundamental requirement . Moreover, placing the centre of gravity as close as possible to the ground is desirable for the manoeuvrability of the motorcycle , but the space in the lower part of the motorcycle is occupied by components related to the engine , forcing the additional weight to be positioned higher .

[0005] A general reduction in volume and mass is thereforedesirable .

[0006] Hence , there is a strong demand in the sector for a brake-by-wire braking system that reduces the overall number of components , bulk, and weight , while ensuring adequate braking feel for the driver . DISCLOSURE OF THE INVENTION

[0007] The need for a brake-by-wire braking system that reduces the overall number of components , bulk, and weight , while ensuring adequate braking feel for the driver, is met by a pressure simulator device for a brake-by-wire braking system for vehicles , comprising :

[0008] - an absorber body comprising an absorber chamber containing a hydraulic fluid;

[0009] - a first fluid connection configured to permit the exchange of hydraulic fluid between the absorber chamber and a fluid reservoir ;

[0010] - a plunger housed in the absorber chamber suitable for being urged by a manual actuation device ;

[0011] - a movable component , slidable in the absorber chamber along a main direction and connected to the plunger by means of a first elastic element ;

[0012] - a second elastic element fixed on one side to the absorber body and on the other side to the movable component , said second elastic element being positionedto at least partially counteract the movement of the movable component in a first sliding direction of the two sliding directions along the main direction;

[0013] - a blocking mechanism configured to limit or prevent the sliding of the movable component in the first sliding direction along the main direction upon reaching a predetermined position of the movable component , so as to bypass the counteracting action of the second elastic element .

[0014] According to one embodiment , the pressure simulator device comprises :

[0015] - a sealing interface between the movable component and the absorber body, configured to divide the absorber chamber into a first sub-chamber and a second sub-chamber defining two separate volumes ;

[0016] - a second fluid connection, configured to permit the exchange of hydraulic fluid between the first subchamber and a fluid reservoir when the movable component is in a rest position, said second fluid connection being configured to be closed as a result of the displacement of the movable component so as to determine the hydraulic isolation of the second sub-chamber from the fluid reservoir ; wherein the first fluid connection is configured to permit the exchange of hydraulic fluid between the first absorber sub-chamber and the fluidreservoir .

[0017] According to one embodiment , the pressure simulator device comprises a pressure sensor configured to measure the fluid pressure in the second sub-chamber and a control unit configured to receive an electrical signal from the pressure sensor and to calculate a signal indicating a braking action proportional to the electrical signal from the pressure sensor to be sent to an actuator group of the braking system.

[0018] According to one embodiment , the pressure simulator device comprises a mechanical block connected to the movable component suitable for interfering with a blocking element integral with the absorber body, for example a bottom wall of the absorber body, so as to prevent the sliding of the movable component in the first sliding direction along the main direction upon reaching a predetermined position of the movable component such as to bypass the counteracting action of the second elastic element .

[0019] According to one embodiment , the pressure simulator device comprises an axial stop in the main direction suitable for sl idably engaging the absorber body and dividing the absorber chamber into a first sub-chamber and a second sub-chamber defining two fluid volumes communicating with each other, i . e . , not sealinglyseparated .

[0020] According to one embodiment , the pressure simulator device comprises at least one proj ecting element in the main direction suitable for abutting a bottom wall of the absorber body .

[0021] According to one embodiment , the pressure simulator device comprises a position sensor configured to detect the stroke of the plunger and a control unit configured to receive a signal from the position sensor and to calculate a s ignal indicating a braking action proportional to the signal from the position sensor to be sent to an actuator group of the braking system .

[0022] According to one embodiment , the pressure simulator device comprises a position sensor which includes a magnet or an electromagnet directly installed on the plunger and a magnetic or electromagnetic field detection sensor suitable for detecting the variation in magnetic or electromagnetic field due to the magnet or electromagnet to generate a position signal of the position sensor .

[0023] According to one embodiment , a method for simulating a pressure in a pressure simulator device comprises the following steps :

[0024] following a short stroke of the plunger, closing the second fluid connection as a result of the change in position of the movable component and isolating a fluid volume of the second sub-chamber .

[0025] According to one embodiment , throughout the entire stroke of the plunger the first fluid connection always remains open .

[0026] A brake-by-wire braking system comprises at least one pressure simulator device , a manual actuation device , such as a lever or a pedal , for exerting the request for braking action, said manual actuation device being connected to the plunger, and an actuator group configured to generate a pressure on the mechanical means suitable for performing a braking action of the vehicle , for example brake calipers . DESCRIPTION OF THE DRAWINGS

[0027] Further features and advantages of the present invention will become more apparent from the following description of preferred, non-limiting embodiments thereof , in which :

[0028] - Figure 1 shows a schematic view of a pressure simulator device according to one embodiment of the present invention;

[0029] - Figure 2 shows a schematic view of a pressuresimulator device according to another embodiment of the present invention .DETAILED DESCRIPTION

[0030] With reference to the aforementioned figures , the reference number 100 globally denotes a pressure simulator device for a brake-by-wire braking system .

[0031] The pressure simulator device 100 comprises an absorber body 10 , for example a cylinder, comprising an absorber chamber 14 which houses a hydraul ic fluid .

[0032] According to a first embodiment , illustrated for example in Figure 1 , a fluid reservoir 1 is connected to the absorber body 10 via a first fluid connection 4 and a second fluid connection 3 , for example one or more openings formed in the absorber body 10 .

[0033] According to one embodiment , a sealing interface 9 between the movable component 8 and the absorber body 10 is configured to divide the absorber chamber 14 into a first sub-chamber 141 and a second sub-chamber 142 , defining two separate volumes . In other words , the first sub-chamber 141 is isolated from the second sub-chamber 142 , and the passage of hydraulic fluid between the first sub-chamber 141 and the second sub-chamber 142 is not allowed, except through the fluid reservoir 1 .

[0034] According to one embodiment , the sealing interface 9 comprises a gasket or an O-ring installed on the movable component 8 , sliding in a sealed manner along an inner lateral surface defining the absorber chamber 14 of the absorber body 10 .

[0035] According to one embodiment , a first fluid connection 4 is configured to permit the exchange of hydraulic fluid between the absorber chamber 14 and the fluid reservoir 1 . In particular, the first fluid connection 4 is configured to permit the exchange of hydraulic fluid between the first absorber sub-chamber 141 and the fluid reservoir 1 . A second fluid connection 3 is configured to permit the exchange of hydraulic fluid between the second sub-chamber 142 and the fluid reservoir 1 when the movable component 8 is in its rest position . The second fluid connection 3 is configured to be closed as a result of the displacement of the movable component 8 , thereby determining the hydraulic isolation of the second sub-chamber 142 from the fluid reservoir 1 .

[0036] The pressure simulator device 100 also comprises a plunger 5 housed in the absorber chamber 14 of the absorber body 10 , to which an actuation device , preferably a manual actuation device 2 , i . e . a lever or a pedal , is suitable for being connected or is connected .The movement of the plunger 5 inside the absorber chamber14 is counteracted by a first elastic element 6 , for example a first spring, which connects the plunger 5 to the movable component 8 . The movable component 8 is slidable in the absorber chamber 14 along a main direction X and i s connected to the plunger 5 by means of the first elastic element 6 . A second elastic element 7 , for example a second spring, is fixed on one side to the absorber body 10 and on the other side to the movable component 8 . The second elastic element 7 is pos itioned to at least partially counteract the movement of the movable component 8 in a first sliding direction XI of the two sliding directions XI , X2 along the main direction X . In particular, the first sliding direction XI is opposite to a second sliding direction X2 , along the same main direction X .

[0037] The pressure simulator device 100 also comprises a blocking mechanism 80 , configured to limit or prevent the sliding of the movable component 8 in the first sliding direction XI along the main direction X upon reaching a predetermined position of the movable component 8 , so as to bypass the counteracting action of the second elastic element 7 . This occurs in particular when the second fluid connection 3 is closed as a result of thedisplacement of the movable component 8 , caused by the displacement of the plunger 5 , thereby determining the hydraulic isolation of the second sub-chamber 142 from the fluid reservoir 1 .

[0038] According to one embodiment , the absorber body 10 i s therefore connected to a fluid reservoir 1 via two connections : a f irst fluid connection 4 ( for example an opening formed in the absorber body 10 , such as in the cylinder ) positioned between the plunger 5 and the movable component 8 along the main direction X, and the second fluid connection 3 ( for example a second opening formed in the absorber body 10 , such as in the cylinder ) positioned between the movable component 8 and a bottom wall 181 of the absorber body 10 along the main direction X .

[0039] For example , the bottom wall 181 is a wall perpendicular to the inner lateral surface defining the absorber chamber 14 of the absorber body 10 . For example , it is the base wall of the absorber body 10 when it is a cylinder .

[0040] Preferably, during the entire stroke of the plunger 5 , the first fluid connection 4 always remains open, so as to function as a calibrated ori fice to dampen thesystem . The second fluid connection 3 instead, after a short stroke , is occluded by the sealing interface 9 as a result of the change in position of the movable component 8 . During the very first part of the stroke , when both connections 3 and 4 to the fluid reservoir 1 are open, the reaction force, given by the system to the force applied by the driver through the manual actuation device 2 , is provided by the series of the first elastic element 6 and the second elastic element 7 . Almost immediately, after a short stroke , the second connection 3 closes and the fluid volume of the second sub-chamber 142 , i . e . for example between the movable component 8 and the bottom wall of the absorber body 10 , behaves like a rigid body . In this phase , therefore , the elastic behaviour of the system is ensured only, or almost exclusively, by the first elastic element 6 .

[0041] According to one embodiment , the pressure simulator device 100 comprises a pressure sensor 11 , configured to measure the fluid pressure in the second sub-chamber 142 .

[0042] According to one embodiment , the pressure simulator device 100 comprises a control unit 70 , for example an electronic processing and control unit comprising an electronic proces sor, configured to receive an electrical signal from the pressure sensor 11 and to calculate asignal indicating a braking action proportional to the electrical signal from the pressure sensor 11 to be sent to an actuator group of the braking system .

[0043] According to one embodiment , the control unit 70 is arranged externally to the pressure simulator device 100 and is operatively connected to it . According to another embodiment , the control unit 70 is integrated in the pressure simulator device 100 .

[0044] According to one embodiment , for example shown in Figure 2 , the blocking mechanism 80 comprises a mechanical block 91 connected to the movable component 8 and suitable for interfering with a blocking element 18 integral with the absorber body 10 , for example the bottom wall 181 of the absorber body 100 , so as to prevent the sliding of the movable component 8 in the first sliding direction XI along the main direction X upon reaching a predetermined position of the movable component 8 . This results in bypassing the counteracting action of the second elastic element 7 .

[0045] In particular, preferably, the mechanical block 91 is an axial stop in the main direction X suitable for slidably engaging the absorber body 10 and dividing the absorber chamber 14 into a first sub-chamber 141 and a second sub-chamber 142 defining two fluid volumescommunicating with each other, i . e . , not sealingly separated .

[0046] Preferably, the axial stop in the main direction X comprises at least one proj ecting element 92 in the main direction X suitable for abutting the bottom wall 181 of the absorber body 10 .

[0047] According to thi s embodiment , the absorber body 10 is therefore connected to the fluid reservoir 1 via a first fluid connection 4 , for example a first opening, positioned between the plunger 5 and the movable component 8 along the main direction X and, for example , the second fluid connection 3 is not necessary . For example , the absorber body 10 is connected to the fluid reservoir 1 only via the first fluid connection 4 . During the entire stroke of the plunger 5 , the first fluid connection 4 remains always open, so as to function as a calibrated ori fice to dampen the system.

[0048] The movable component 8 does not include any sealing interface nor any gasket , allowing the hydraulic fluid to pass freely between the first sub-chamber 141 and the second sub-chamber 142 within the absorber body 10 .

[0049] According to one embodiment , the plunger 5 , the movable component 8 , the first elastic element 6 , thesecond elastic element 7 and the blocking mechanism 80 are positioned in such a way as to always leave the first fluid connection 4 open throughout the stroke of the plunger 5 .

[0050] Preferably, the mechanical block 91 is configured so that the stroke of the control o f the manual actuation device 2 is divided into two di f ferent phases : in the first phase , the reaction force to the driver' s command is provided by the series of the first elastic element 6 and the second elastic element 7 , whereas , once the movable component 8 reaches a position in which the mechanical block 91 acts , that is for example when the proj ecting element 92 abuts the blocking element 18 , the reaction force i s provided by the first elastic element 6 . Preferably, the blocking element 18 is , for example , the bottom wall 181 or another proj ecting element of the absorber body 10 .

[0051] According to this configuration, there may be a single fluid connection 4 to the fluid reservoir 1 , since the two volumes of the sub-chambers 141 , 142 inside the absorber body 10 are in communication .

[0052] According to one embodiment , the pressure simulator device 100 comprises a position sensor 12 configured todetect the stroke of the plunger 5 , and the control unit70 is configured to receive a signal from the position sensor 12 and to calculate a signal indicating a braking action proportional to the signal from the position sensor 12 to be sent to the actuator group of the braking system .

[0053] According to one embodiment , the position sensor 12 comprises a magnet or an electromagnet 121 directly installed on the plunger 5 and a magnetic or electromagnetic field detection sensor 122 suitable for detecting the variation in magnetic or electromagnetic field due to the magnet or electromagnet 121 to generate a position signal of the position sensor 12 .

[0054] It is clear that the present invention also relates to a sub-assembly comprising a pressure simulator device 100 according to any of the variants described in this document and a manual actuation device 2 , such as a lever or a pedal , for exerting the request for braking action connected to the pressure simulator device 100 , in particular to the plunger 5 .

[0055] Furthermore , the present invention also relates to a brake-by-wire braking system comprising :

[0056] - at least one pressure simulator device 100according to any of the embodiments described in this document ,

[0057] - a manual actuation device 2 , such as a lever or a pedal , for exerting the request for braking action, said manual actuation device being connected to the plunger 5 ,

[0058] - an actuator group configured to generate a pressure on the mechanical means suitable for performing a braking action of the vehicle , for example brake calipers .

[0059] As can be appreciated from the above description, the pressure simulator device according to the invention makes it possible to overcome the drawbacks presented in the known art .

[0060] In particular, the integration o f the absorber and the driver control into a single sub-assembly signi ficantly reduces the number of components required in the brake-by-wire system . This consolidation minimises the overall volume and weight of the braking system, which is particularly advantageous for motorcycles where space is limited and low weight is crucial . The absorber, integrated within the driver control , simulates the traditional hydraulic braking feel , providing the driver with a familiar feedback while maintaining the advantages of an electro-hydraulic system . The hydraulic connectionto a fluid reservoir ensures constant fluid management and system damping, improving the reliability and performance of the braking system . The arrangement of the plunger, the movable component and the elastic elements within the absorber body ensures a controlled and responsive braking action, improving the overall ef ficiency and safety of the vehicle ' s braking system .

[0061] A person skilled in the art , for the purpose of meeting contingent and speci fic requirements , may make numerous changes and modi fications to the invention described above , all of which fall within the scope of the invention as defined by the following claims .

Claims

Claims1. A pressure simulator device (100) for a brake-by-wire braking system for vehicles, comprising:- an absorber body (10) comprising an absorber chamber (14) containing a hydraulic fluid;- a first fluid connection (4) configured to permit exchange of hydraulic fluid between the absorber chamber (14) and a fluid reservoir (1) ; a plunger (5) contained in the absorber chamber (14) suitable for being urged by a manual actuation device (2) ;- a movable component (8) , sliding in the absorber chamber (14) along a main direction (X) and connected to the plunger (5) by means of a first elastic element (6) ;- a second elastic element (7) fixed on one side to the absorber body (10) and on another side to the movable component (8) , said second elastic element (7) being positioned to at least partially counteract the movement of the movable component (8) in a first sliding direction (XI) of the two sliding directions (XI, X2) along the main direction (X) ;- a blocking mechanism (80) configured to limit or prevent the sliding of the movable component (8) in the first sliding direction (XI) along the main direction (X) upon reaching a predetermined position of the movable component (8) , so as to bypass the counteracting action of the second elastic element (7) ,wherein the blocking mechanism comprises a mechanical block (91) connected to the movable component (8) suitable for interfering with a blocking element (18) integral with the absorber body (10) , so as to prevent sliding of the movable component (8) in the first sliding direction (XI) along the main direction (X) upon reaching a predetermined position of the movable component (8) such as to bypass the counteracting action of the second elastic element (7) .

2. Pressure simulator device (100) according to claim 1, wherein the blocking element (18) is a bottom wall (181) of the absorber body (10) .

3. Pressure simulator device (100) according to claim 1 or 2, wherein the mechanical block (91) is an axial stop in the main direction (X) suitable for slidably engaging the absorber body (10) and dividing the absorber chamber (14) into a first sub-chamber (141) and a second sub-chamber (142) which define two fluid volumes communicating with each other, i.e. not sealingly separated.

4. Pressure simulator device (100) according to claim 3, wherein the axial stop in the main direction (X) comprises at least one projecting element (92) toward the main direction (X) , suitable for abutting a bottom wall (181) of the absorber body (10) .

5. Pressure simulator device (100) according to any one of the preceding claims, comprising a position sensor (12) configured to detect the stroke of the plunger (5) and acontrol unit (70) configured to receive a signal from the position sensor (12) and to calculate a signal indicating a braking action proportional to the signal from the position sensor (12) to be sent to an actuator group of the braking system.

6. Pressure simulator device (100) according to claim 5, wherein the position sensor (12) comprises a magnet or electromagnet (121) directly installed on the plunger (5) and a magnetic or electromagnetic field detection sensor (122) suitable for detecting the change in magnetic or electromagnetic field due to the magnet or electromagnet (121) to generate a position signal of the position sensor (12) .

7. Pressure simulator device (100) according to any one of the preceding claims, wherein the first fluid connection (4) comprises an opening made in the absorber body (10) and positioned between the plunger (5) and the movable component(8) along the main direction X.

8. Pressure simulator device (100) according to any one of the preceding claims, wherein the absorber body (10) is connected to the fluid reservoir (1) only via the first fluid connection (4) .

9. Pressure simulator device (100) according to any one of the preceding claims, wherein the plunger (5) , the movable component (8) , the first elastic element (6) , the second elastic element (7) and the blocking mechanism (80) arepositioned so as to always leave the first fluid connection(4) open throughout the stroke of the plunger (5) .

10. A brake-by-wire braking system (100) comprising:- at least one pressure simulator device (100) according to any one of the preceding claims, a manual actuation device (2) , such as a lever or pedal, for exerting the request for braking action, said manual actuation device being connected to the plunger(5) , - an actuator group configured to generate a pressure on the mechanical means suitable for performing a braking action of the vehicle, for example, brake calipers.

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