Primary gasket for a cylinder assembly, and cylinder assembly

Abstract

The present invention relates to a primary gasket 1 for a cylinder assembly 100, wherein the primary gasket 1 comprises an annular body 2 extending circumferentially at least along a circumferential direction C-C about an axial direction X-X, wherein said primary gasket 1 defines a radial direction R-R perpendicular to said axial direction X-X and said circumferential direction C-C, wherein said annular body 2 is configured to be housed in a primary gasket seat 105, wherein the primary gasket seat 105 is delimited radially by an axial seat wall 107 and axially by a first radial seat wall 108 and a second radial seat wall 109 connected, for example as an undercut, to said axial seat wall 107, wherein said annular body 2 comprises an inner lip 4, an outer lip 6, and a back portion 3, wherein the back portion 3 comprises a back abutment surface 13 configured to abut against the first radial seat wall 108 of said primary gasket seat 105, wherein the inner lip 4 and the outer lip 6 extend axially from the back portion 3, on the opposite side of the back abutment surface 13, radially spaced apart from each other, wherein the inner lip 4 comprises an inner lip surface 19 configured to form a seal with said float 102, wherein the outer lip 6 comprises an outer lip surface 20 configured to form a seal with said axial seat wall 107, wherein the inner lip 4 comprises an annular root 14 extending axially between said back portion 3 and a root edge 15, wherein the inner lip 4 comprises a plurality of protuberances 9, 10, wherein each protuberance 9, 10 projects axially from said root edge 15, wherein the gasket 1 delimits a plurality of channels 5, 7 extending on the back portion 3 and at least partially on the outer lip 6, avoiding abutting against the first radial seat wall 108 of said primary gasket seat 105 and against said axial seat wall 107, respectively, wherein each protuberance 9, 10 is circumferentially offset with respect to each channel 5, 7, so that each gasket section passing through the axial direction X-X and the radial direction R-R, which crosses any protuberance 9, 10 of the plurality of protuberances 9, 10, avoids crossing any channel 5, 7 of the plurality of channels 5, 7.

Description

"Primary gasket for a cylinder assembly, cylinder assembly"DESCRIPTION

[0001] . Field of the invention

[0002] . The present invention relates to a primary gasket for a cylinder assembly, as well as to a cylinder assembly for a hydraulic and / or electrohydraulic system of a vehicle .

[0003] . Background art

[0004] . In the field of cylinder assemblies for hydraulic and / or electrohydraulic systems in a vehicle, such as master cylinders and / or brake actuators , it is known to arrange a sealingly movable float inside a hollow cylinder which defines an axial direction X-X, and a radial direction R-R perpendicular to the axial direction .

[0005] . The float is axially movable in the hollow cylinder between a resting configuration and at least one advanced configuration to pressuri ze a fluid, e . g . , a brake fluid, in a pressure chamber in the hollow cylinder .

[0006] . When the float is in a resting configuration, the pressure chamber is in fluid communication with a fluid reservoir by means of a feeding conduit . When the float is in a resting configuration, the pressure in the pressure chamber is equal to the pressure of the reservoir . When the float advances axially toward the at least one advanced configuration, the pressure chamber and the reservoir are fluidly isolated, allowing the fluid in the pressure chamber to be pressurized .

[0007] . The float is axially movable by sliding tightly on a primary gasket and a secondary gasket which are housed in respectiveseats or grooves , a primary seat and a secondary seat , made in the wall of the hollow cylinder . The primary seat and the secondary seat are made in the wall of the hollow cylinder . The feeding conduit leads radially from the hollow cylinder wall into a feeding opening arranged between the primary seat and the secondary seat .

[0008] . The secondary gasket is adapted to form a static and dynamic seal between the cylinder and the float to avoid the fluid in the reservoir and / or pressure chamber, when in fluid communication with the reservoir, from flowing into the cylinder in the opposite direction to the pressure chamber . For example, the secondary gasket serves the function of hydraulically isolating the components housed in the cylinder on the side opposite to the pressure chamber, and / or preventing leakages of hydraulic fluid from the pressure chamber and / or from the cylinder .

[0009] . The primary gasket is adapted to keep the fluid pressurized in the pressure chamber, preventing fluid passages from the pressure chamber to the reservoir when the float is in an advanced position in the cylinder . In this case, the primary gasket is in a fluid isolation configuration, with at least one back portion thereof abutting against a first radial wall of primary seat .

[0010] . I f the hydraulic system needs a further pressure increase, such as during bench flow tests , for example, at least one valve which increases the pressure in the reservoir is opened in order to trigger a flow of fluid from the reservoir to the pressure chamber, avoiding the primary gasket from preventing such a passage of fluid, thus increasing the pressure in the pressure chamber . Under otherconditions , for example during purging, the reservoir is at ambient pressure and the pressure chamber is under negative pressure with respect to the reservoir, triggering a flow of fluid from the reservoir to the pressure chamber, avoiding the primary gasket from preventing such a passage of fluid, thus increasing the pressure in the pressure chamber

[0011] . In order to ful fill this function, the primary gasket can be a two-lip gasket comprising an inner lip and an outer lip which proj ect from the back portion to be radially and mutually spaced apart . The inner lip is configured to form a seal with the float . The outer lip is configured to form a seal with an outer wall of the primary seat when the pressure in the pressure chamber is higher than the pressure in the reservoir, thus fluidly isolating the pressure chamber and the reservoir . The outer lip is configured to bend toward the central lip moving away from the outer wall of the seat when the pressure in the reservoir is higher than the pressure in the pressure chamber, thus allowing a fluid communication between the reservoir and the pressure chamber . The inner lip comprises a plurality of protuberances adapted to interfere with a second radial wall of the primary seat , for example by bending, opposite to the first radial wall , so as to obtain a plurality of openings between a protuberance and a first neighboring protuberance which allows a passage of fluid when the reservoir pressure exceeds the pressure of the pressure chamber, bending the outer lip toward the inner lip, allowing the fluid connection of the reservoir and the pressure chamber, thus allowing the pressure in the pressure chamber to increase . In addition, the outer lip and the back have a pluralityof channels which facilitate the bending of the outer lip when the reservoir pressure exceeds the pressure of the pressure chamber .

[0012] . In the industry, it has been found that the primary gaskets of known type provided with advanced float , with the pressure chamber pressure exceeding the reservoir pressure , abut against the back portions delimited between the plurality of grooves , and can be subj ect to an excessive deformation which accelerates the gasket wear, increasing the risk of malfunction and / or needing increased maintenance .

[0013] . In the industry, it has been found that the primary gaskets of known type can exhibit some difficulties during assembly, due to the provision of protuberances adapted to bend and that can get stuck between the cylinder wall and the float during assembly .

[0014] . Therefore , the need to make primary gaskets which allow a high flow when the primary gasket operates in the fluid communication configuration, while improving the wear resistance of the primary gasket , is strongly felt in the industry .

[0015] . Therefore , the need to facilitate the assembly of the primary gasket , reducing the risk of j amming between the gasket , the float, and the cylinder, is strongly felt in the industry .

[0016] . Solut ion

[0017] . The present invention aims at providing a primary gasket for a cylinder assembly which allows solving the prior art problems complained of .

[0018] . This and other obj ects and advantages are achieved by a primary gasket as well as by a cylinder assembly according to the independent claims .

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

[0020] . By virtue of the suggested solutions , a high fluid passage can be ensured when the reservoir pressure is higher than the pressure chamber pressure , reducing the fluid passage resistance compared to the prior art .

[0021] . By virtue of the suggested solutions , greater wear resistance can be ensured by reducing the tendency of the primary gasket to deform while maintaining the pressure in the pressure chamber .

[0022] . By virtue of the suggested solutions , it is possible to ensure less gasket deformation than is known, thus reducing the master cylinder absorption, i . e . , it is possible to generate a certain pressure with a smaller piston travel . By virtue of the suggested solutions , an easier installation of the primary gasket can be ensured by avoiding j amming between the primary gasket and the cylinder when mounting the float in the cylinder .

[0023] . By virtue of the suggested solutions , it is possible to decrease the wear due to the rubbing of the piston which moves inside the hydraulic master cylinder when braking actions are performed .

[0024] . By virtue of the suggested solutions , it is possible to obtain a gasket having a sufficiently flexible structure so as to facilitate the assembly thereof on the housings of the inverted hydraulic master cylinder .

[0025] . By virtue of the suggested solutions , it is possible to obtain a gasket which ensures an adequate brake fluid flow .

[0026] . Figures

[0027] . Further features and advantages of the primary gasket and the cylinder assembly will become apparent from the following description of preferred embodiments thereof , given by way of nonlimiting indication, with reference to the accompanying drawings , in which :

[0028] . - figure 1 is an axonometric view of a primary gasket according to the present invention, in which an annular gasket body having an inner lip and an outer lip proj ecting in an axial direction from a gasket back portion can be seen, where the inner lip comprises at an end thereof a plurality of protuberances interspersed with a plurality of discharges , the protuberances being configured to interfere with a radial wall of a primary gasket seat ;

[0029] . - figure 2 is an axonometric view of the primary gasket in figure 1 seen from an opposite direction, in which the back portion of the primary gasket can be seen, where the back portion comprises a plurality of discharges interspersed with a plurality of protuberances , the protuberances being configured to abut against a radial gasket wall of a primary gasket seat , where the plurality of discharges continue on the outer lip in so as to allow a passage of fluid when the reservoir pressure is greater than the pressure of the pressure chamber ;

[0030] . - figure 3 is a front view of the primary gasket in figure 1 , in which the protuberances of the inner lip, having a circular section extension, can be seen;

[0031] . - figure 4 shows the primary gasket in figure 3 , in which there can be seen the discharges , dashed, of the back and the outerlip interspersed with the protuberances of the inner lip, avoiding axial overlaps between the protuberances of the inner lip and the discharges of the outer lip;

[0032] . - figure 5 shows the gasket in figure 1 sectioned along a plane parallel to the radial direction R-R and comprising the radial direction R-R and the axial direction X-X in figure 3 , in which the central lip and the back portion are sectioned at a discharge of the plurality of discharges ;

[0033] . - figure 6 shows the gasket in figure 1 sectioned along a plane parallel and comprising the radial direction R-R shown in figure 3 , in which the inner lip is sectioned at a protuberance of the plurality of protuberances ;

[0034] . - figure 7 is an axonometric view of a cylinder assembly according to the present invention, e . g . , a master cylinder actuatable by a lever to pressuri ze a fluid, or a linear actuator for BBW (Brake By Wire ) systems governed by an electric motor to pressurize a brake fluid;

[0035] . - figure 8 is a section view of the cylinder assembly in figure 7 sectioned along a section plane perpendicular to the axial direction X-X and the radial direction R-R, in which there can be seen the float or piston slidingly housed in the float seat made in the sealed cylinder by virtue of the primary gasket in figure 1 , and a secondary gasket ;

[0036] . - figure 9 is a detail of figure 8 , in which the gasket is shown in section in an undeformed configuration superimposed on the section of the annular seat made in the cylinder adapted to accommodate the gasket in the deformed configuration .

[0037] . Description of some preferred embodiments

[0038] . According to a general embodiment, a primary gasket for a cylinder assembly is indicated by reference numeral 1 . Said cylinder assembly 100 comprises a cylinder 101 and a float 102 slidingly housed in a float seat 104 delimited by a cylinder wall 103 of said cylinder 101 for pressurizing a fluid . For example , said cylinder assembly 100 is a master cylinder or an electrically controlled actuator .

[0039] . The primary gasket 1 comprises an annular body 2 , which extends circumferentially at least along a circumferential direction C-C about an axial direction X-X, where said primary gasket 1 defines a radial direction R-R perpendicular to said axial direction X-X and said circumferential direction C-C .

[0040] . Said annular body 2 is configured to be housed in a primary gasket seat 105 defined in said cylinder wall 103 , where the primary gasket seat 105 is delimited radially by an axial seat wall 107 and axially by a first radial seat wall 108 and a second radial seat wall 109 connected, for example as an undercut , to said axial seat wall 107 .

[0041] . Said annular body 2 comprises an inner lip 4 , an outer lip 6, and a back portion 3 .

[0042] . The back portion 3 comprises a back abutment surface 13 configured to abut against the first radial seat wall 108 of said primary gasket seat 105.

[0043] . The inner lip 4 and the outer lip 6 extend axially, in axial direction X-X, from the back portion 3 , on the opposite side of the back abutment surface 13, radially spaced apart from eachother .

[0044] . The inner lip 4 comprises an inner lip surface 19 configured to form a seal with said float 102 .

[0045] . The outer lip 6 comprises an outer lip surface 20 configured to form a seal with said axial seat wall 107 .

[0046] . The inner lip 4 comprises an annular root 14 extending axially between said back portion 3 and a root edge 15 .

[0047] . The inner lip 4 comprises a plurality of protuberances 9, 10 , where each protuberance 9, 10 proj ects axially from said root edge 15 .

[0048] . The gasket 1 delimits a plurality of channels 5 , 7 extending on the back portion 3 and at least partially on the outer lip 6, avoiding abutting against the first radial seat wall 108 of said primary gasket seat 105 and against said axial seat wall 107 , respectively .

[0049] . According to an aspect , each protuberance 9 , 10 is circumferentially of fset with respect to each channel 5, 7 , so that each gasket section passing through the axial direction X-X and the radial direction R-R, which crosses any protuberance 9 , 10 of the plurality of protuberances 9, 10 , avoids crossing any channel 5, 7 of the plurality of channels 5, 7 .

[0050] . In the present disclosure, said each gasket section passing through the axial direction X-X and the radial direction R- R, which crosses any protuberance 9 , 10 of the plurality of protuberances 9 , 10 , while avoiding crossing any channel 5, 7 of the plurality of channels 5, 7 , is considered to be the section which crosses the gasket at any protuberance 9, 10 of the plurality ofprotuberances 9, 10 as shown in figure 6 or figure 9. In other words , with said each gasket section, the sectioned gasket portion comprising said any protuberance 9, 10 of the plurality of protuberances 9 , 10 is exclusively considered .

[0051] . By virtue of the provision of protuberances on the inner lip, adapted to abut against a radial surface of the gasket seat, and channels adapted to avoid abutting against the other radial surface of the gasket seat , where the channels and the protuberances are not axially aligned with one another, it is possible to achieve high stability of the gasket in its seat, which allows reducing the deformations during the actuation, i . e . , when the pressure of the pressure chamber is higher than the pressure of the reservoir, while allowing a high flow during the feeding, i . e . , when the pressure of the reservoir is higher than the pressure of the pressure chamber .

[0052] . According to an embodiment, the back portion 3 comprises a connection surface 21 configured to connect the back abutment surface 13 and the inner lip surface 19. According to an embodiment, the connection surface 20 forms a curvilinear concave surface on the gasket body 2 . According to an embodiment, the connection surface 20 is the footprint of the outer surface of a toroid .

[0053] . According to an embodiment, on the inner lip surface 19, the inner lip 4 comprises at least one circumferential groove 11 , preferably at least three circumferential grooves 11 , extending along the direction C-C thus creating a depression in the inner lip 4 .

[0054] . According to an embodiment, in each gasket section passing through the axial direction X-X and the radial direction R-R, theconnection surface 21 forms a connection arc 22 , preferably an arc of a circumference .

[0055] . According to an embodiment, said plurality of protuberances 10 , 9 and said root edge 15 define a plurality of discharges 8 .

[0056] . According to an embodiment, each discharge 8 is delimited by each protuberance 10 and one of the first neighboring protuberances 9 of said plurality of protuberances 10 , 9 and by a free edge portion 16 of said root edge 15 extending between each protuberance 10 and the first neighboring protuberance 9 .

[0057] . According to an embodiment, each protuberance 9, 10 comprises a protuberance body 17 proj ecting at least from said annular root 14 and a protuberance head 18 connected to said protuberance body 17 . According to an embodiment, each protuberance body 17 proj ects from an opposite side with respect to the back portion .

[0058] . According to an embodiment, each protuberance 9, 10 extends parallel to the axial direction X-X, and is configured to abut against a radial wall of the gasket seat, compressively working and avoiding bending . According to an embodiment, each protuberance 9, 10 is configured to compressively work along a direction parallel to the axial direction X-X avoiding bending . In an embodiment, each protuberance 9 , 10 comprises a protuberance collar 12 connecting the protuberance body 17 and / or the protuberance head 18 to the root edge 15 on the opposite side of the outer lip 6 by tapering in the direction of the protuberance head 18 . In an embodiment , each protuberance collar 12 only partially surrounds the respectiveprotuberance body, on the side radially opposite to the outer lip 6. In an embodiment, each protuberance collar 12 is a boss forming a thickening with respect to the protuberance body 17 .

[0059] . According to an embodiment, said protuberance head is configured to abut against said second radial seat wall 109, avoiding said root edge 15 from abutting against said second radial seat wall 109 allowing a passage of fluid through said plurality of discharges 8 .

[0060] . According to an embodiment, the protuberance body 17 and / or each protuberance body 17 is at least partially in the shape of a column, preferably cylindrical and / or prismatic . In an embodiment, said protuberance head 18 is made in one piece with said protuberance body 17 .

[0061] . According to an embodiment, said protuberance head 18 and / or each protuberance head 18 is tapered with respect to said protuberance body 17 , preferably being rounded in shape in the direction opposite to said annular root such as hemispherical or like a spherical cap, so that it abuts against a circular surface .

[0062] . By virtue of the provision of protuberances with columnshaped body and rounded head, it is possible to obtain a greater compressibility of the protuberance , allowing easier assembly of the gasket into its seat, keeping, once assembled, the gasket elastically abutting with each protuberance and the back abutment surface against the first radial wall of primary seat and against the second radial wall of primary seat .

[0063] . According to an embodiment, each protuberance body 17 proj ects from said back portion 3 and is at least partially embeddedin said annular root 14 .

[0064] . According to a further aspect and / or according to an embodiment, each protuberance protrudes in the axial direction X-X from said root edge 15, and protrudes at least partially in the radial direction R-R from the annular root 14 , in particular from the surface of the inner lip 4 facing the outer lip 6, each protuberance forming a rib mainly extending in the axial direction X-X along the annular root 14 .

[0065] . According to an embodiment, each protuberance body 17 protrudes at least partially in the radial direction R-R from the annular root 14 , each forming a rib mainly extending in the axial direction X-X along the annular root 14 . According to an embodiment, each protuberance body 17 protrudes radially with a column-shaped body portion forming a discontinuity circumferentially on the surface of the inner lip 4 facing the outer lip 6.

[0066] . By virtue of the provision of the protuberances 9, 10 protruding both in the axial direction and partially in the radial direction from the annular root 14 , it is possible to equalize the contact pressures between float and gasket, avoiding accelerated and uneven wear . In addition, by virtue of the provision of the protuberances 9 , 10 protruding both in the axial direction and partially in the radial direction from the annular root 14 , it is possible to form ribs which reinforce the gasket and have an end portion abutting on the seat before the insertion of the float, facilitating the assembly of the gasket and avoiding damage to the gasket itsel f upon insertion of the float .

[0067] . According to an embodiment, said plurality of channels 5 ,7 divides said back abutment surface 13 into a plurality of circular abutment sectors 23 , preferably being in the shape of a circular crown arch .

[0068] . According to an embodiment, each circular abutment sector 23 is configured to abut against the first radial seat wall 108 of said primary gasket seat 105 .

[0069] . According to an embodiment, each circular abutment sector 23 is delimited in the circumferential direction C-C by each channel 5 and a first neighboring channel 7 of said plurality of channels 5, 7 .

[0070] . According to an embodiment, the outer lip surface 20 comprises a circumferential sealing portion 24 extending seamlessly along the circumferential direction C-C to form a seal with said axial seat wall 107 .

[0071] . In an embodiment, said plurality of channels 5 , 7 divides said outer lip surface 20 into a plurality of circumferential sealing sectors 25. In an embodiment , each circumferential sealing sectors 25 is configured to form a seal with said axial seat wall 107 . In an embodiment, each circumferential sealing sector 25 is delimited along the circumferential direction C-C by each channel 5 and a first neighboring channel 7 of said plurality of channels 5 , 7 and is connected to the back portion 3 and the circumferential sealing portion 24 . In an embodiment , the gasket forms a seal with the axial seat wall 104 with the circumferential sealing portion 24 .

[0072] . In an embodiment, each channel 5, 7 extends along a respective longitudinal channel direction A-A from a respective first end 26 on the outer lip 6 to a respective second end 27 . In anembodiment, each first end 26 is delimited by the circumferential sealing sector 25. According to an embodiment, each second end 27 leads into a connection surface 21 configured to connect the back abutment surface 13 and the inner lip surface 19. In this manner, in a step of feeding the cylinder assembly 100 , the fluid upstream of the gasket 1 , e . g . , in the reservoir, enters into the channels from each second end 27 , flows along each longitudinal channel direction A-A, and exits from each first end 26 bending the outer lip 6 toward the inner lip 4 . Moreover, in a step of actuating the cylinder assembly 100 , the fluid downstream of the gasket 1 is prevented from accessing each channel 5, 7 , the first end being inaccessible by virtue of the sealing surface of the outer lip . In an embodiment, for each channel 5, 7 , the gasket 1 defines a channel section perpendicular to the longitudinal channel direction A-A having a U- shaped profile .

[0073] . In an embodiment, each first end 26 is curvilinear . In an embodiment, each channel 5, 7 is connected in a curvilinear manner to the respective two circumferential sealing sectors 25 and to the respective two circular abutment sectors 23 delimiting the channel 5, 7 , avoiding step-like or undercut connections with the outer lip 6 and / or the back portion 3 . In an embodiment, the gasket 1 comprises a channel surface for each channel 5, 7 , which extends along the respective longitudinal channel direction A-A. In an embodiment, each channel surface is at least partially cylindrical , avoiding stepped connections with the outer lip 6 and / or the back portion 3 .

[0074] . In an embodiment , each protuberance 9, 10 defines acircumferential protuberance extension N along the tangential direction which subtends, with respect to a circumference centered on the axial direction X-X, an angle A between 3° and 8°, preferably between 5° and 7°.

[0075] . In an embodiment, each channel 5, 7 defines a circumferential channel extension M along the tangential direction which subtends, with respect to a circumference centered on the axial direction X-X, an angle B between 3° and 8°, preferably between 5° and 7°.

[0076] . In an embodiment, each circular abutment sector 23 defines a circumferential abutment extension L along the tangential direction which subtends, with respect to a circumference centered on the axial direction X-X, an angle E between 15° and 40°, preferably between 25° and 30°.

[0077] . In an embodiment, each discharge 8 defines a circumferential discharge extension H along the tangential direction which subtends, with respect to a circumference centered on the axial direction X-X, an angle F between 15° and 40°, preferably between 25° and 30°.

[0078] . By virtue of the provision of channels with small circumferential extension, it is possible to obtain a high number of channels on the one hand and a safe and stable axial abutment of the plurality of circular abutment sectors on the other hand, allowing a high flow and a reduction in gasket wear.

[0079] . According to an embodiment, the number of said plurality of channels 5, 7 is between 10 and 90, preferably between 12 and 30, even more preferably 12.

[0080] . According to an embodiment, the number of said plurality of protuberances 9 , 10 is between 10 and 90 , preferably between 12 and 30 , even more preferably 12 . According to an embodiment, the number of the channels 5, 7 is equal to number of the protuberances 9, 10 .

[0081] . According to an embodiment , said protuberances of said plurality of protuberances 10 are circumferentially equally spaced apart from one another . In an embodiment, said channels of said plurality of channels 7 are circumferentially equally spaced apart from one another . In an embodiment, each channel 7 is equally spaced apart between each protuberance 9 and the first neighboring protuberance 10 of the plurality of protuberances .

[0082] . By virtue of the provision of said cylindrical protuberance body and / or said rounded protuberance head 18 , it is possible to reduce the exposed surface of the protuberance perpendicularly to the fluid passage direction, allowing a reduction in fluid passage resistance .

[0083] . According to an embodiment , each discharge of said plurality of discharges 8 has a substantially U-shaped profile .

[0084] . According to an embodiment , said root edge 15 is an annular edge .

[0085] . According to an embodiment, the gasket 1 is a two-lip gasket .

[0086] . According to an embodiment, said gasket body is made of polymer material for gaskets , e . g . , gasket rubber, preferably EPDM (Ethylene-Propylene Diene Monomer) .

[0087] . The present invention also relates to a cylinder assembly100 for a braking system.

[0088] . Said cylinder assembly 100 comprises a cylinder 101 . Said cylinder 101 comprises a cylinder wall 103 internally delimiting a float seat 104 . Said cylinder wall 103 delimits a pressure chamber fluidly connectable to a braking device . Said cylinder wall 103 delimits a primary gasket seat 105 and a secondary gasket seat 106. Said cylinder 101 defines a feeding conduit 111 fluidly connectable to a reservoir and / or to a fluid feeding valve, where said feeding conduit 111 leads into a feeding opening 112 on said cylinder wall103 between said primary gasket seat 105 and said secondary gasket seat 106. The primary gasket seat 105 is radially delimited by an axial seat wall 107 and axially by a first radial seat wall 108 and a second radial seat wall 109 connected to said axial seat wall 107 . In an embodiment, the first radial seat wall 108 and the second radial seat wall 109 are parallel to each other and are perpendicular to the axial direction X-X or a direction parallel thereto .

[0089] . Said cylinder assembly 100 comprises a float 102 . The float 102 is slidingly housed in a sealing manner in the float seat104 to pressurize a fluid in a pressure chamber 110 fluidly connectable to a braking device .

[0090] . Said cylinder assembly 100 comprises a primary gasket 1 according to any one of the previously described embodiments . The primary gasket 1 is housed in said primary gasket seat 105 avoiding an axial clearance between said first radial seat wall 108 and said second radial seat wall 109, where each protuberance 9, 10 abuts against said second radial seat wall 109, and where said backabutment surface 13 abuts against said first radial seat wall 108 .

[0091] . Said cylinder assembly 100 comprises a secondary gasket 115 housed in the secondary gasket seat 106 to form a static and dynamic seal with said float and said cylinder wall 103 .

[0092] . According to an embodiment, said secondary gasket 115 is a two-lip gasket .

[0093] . According to an embodiment, said cylinder assembly 100 is a master cylinder .

[0094] . According to an embodiment , said cylinder assembly 100 comprises an elastic element 114 housed inside said cylinder 101 , which constantly biases said float 102 in a direction opposite to a float advancement direction .

[0095] . According to an embodiment, the float 102 is axially movable between a resting configuration and at least one advanced configuration to pressurize a fluid, such as a brake fluid, for example , in the pressure chamber .

[0096] . According to an embodiment, the float comprises a float body having a hollow portion delimited by a float wall , where the hollow portion is in fluid connection with the pressure chamber, where the float wall has a through opening . As long as said through opening is arranged between the primary gasket and the secondary gasket, the pressure chamber is in fluid communication with said feeding conduit through said through opening . When said float is in said advanced configuration, in which said through opening is axially advanced with respect to the primary gasket, the pressure chamber is fluidly isolated from the feeding conduit by means of the primary gasket with the outer lip 6 sealed with the axial seat wall107 and the inner lip sealed with the outer float wall , and the float pressurizes the fluid in the pressure chamber . When the fluid in the feeding conduit exceeds the fluid pressure in the pressure chamber, the fluid passes through the channels 5 , 7 bending the outer lip and allowing the pressure in the pressure chamber to be increased .LIST OF REFERENCE SIGNS1 primary gasket2 annular body3 back portion4 inner lip5 channel6 outer lip7 first neighboring channel8 plurality of discharges9 first neighboring protuberance10 protuberance11 circumferential groove12 protuberance collar13 back abutment surface14 annular root15 root edge16 free edge portion17 protuberance body18 protuberance head19 inner lip surface20 outer lip surface21 connection surface22 connection arc23 circular abutment sector24 circumferential sealing portion25 circumferential sealing sector26 first channel end27 second channel end100 cylinder assembly101 cylinder102 float103 cylinder wall104 float seat105 primary seat or primary gasket seat106 secondary seat or secondary gasket seat107 axial wall of primary seat108 first radial wall of primary seat109 second radial wall of primary seat110 pressure chamber111 feeding conduit112 feeding opening114 elastic element115 secondary gasketX-X axial directionR-R radial directionC-C circumferential directionA-A longitudinal channel directionN circumferential protuberance extensionM circumferential channel extensionL abutment circumferential extensionH circumferential discharge extensionA subtended angle of protuberanceB subtended angle of channelE subtended angle of circumferential sealing sectorF subtended angle of discharge

Claims

CLAIMS1. A primary gasket (1) for a cylinder assembly (100) , wherein said cylinder assembly (100) comprises a cylinder (101) and a float (102) slidingly housed in a float seat (104) delimited by a cylinder wall (103) of said cylinder (101) for pressurizing a fluid, wherein the primary gasket (1) comprises an annular body (2) extending circumferentially at least along a circumferential direction (C-C) about an axial direction (X-X) , wherein said primary gasket (1) defines a radial direction (R-R) perpendicular to said axial direction (X-X) and said circumferential direction (C-C) , wherein said annular body (2) is configured to be housed in a primary gasket seat (105) defined in said cylinder wall (103) , in which the primary gasket seat (105) is delimited radially by an axial seat wall (107) and axially by a first radial seat wall (108) and a second radial seat wall (109) connected, for example as an undercut, to said axial seat wall (107) , wherein said annular body (2) comprises an inner lip (4) , an outer lip (6) , and a back portion (3) , wherein the back portion (3) comprises a back abutment surface (13) configured to abut against the first radial seat wall (108) of said primary gasket seat (105) , wherein the inner lip (4) and the outer lip (6) extend axially from the back portion (3) , on the opposite side of the back abutment surface (13) , radially spaced apart from each other, wherein the inner lip (4) comprises an inner lip surface (19) configured to form a seal with said float (102) ,wherein the outer lip (6) comprises an outer lip surface (20) configured to form a seal with said axial seat wall (107) , wherein the inner lip (4) comprises an annular root (14) extending axially between said back portion (3) and a root edge (15) , wherein the inner lip (4) comprises a plurality of protuberances (9, 10) , wherein each protuberance (9, 10) projects axially from said root edge ( 15) , wherein the gasket (1) delimits a plurality of channels (5, 7) extending on the back portion (3) and at least partially on the outer lip (6) , avoiding abutting against the first radial seat wall (108) of said primary gasket seat (105) and against said axial seat wall (107) , respectively, characterized in that each protuberance (9, 10) is circumferentially offset with respect to each channel (5, 7) , so that each gasket section passing through the axial direction (X-X) and the radial direction (R-R) , which crosses any protuberance (9, 10) of the plurality of protuberances (9, 10) , avoids crossing any channel (5, 7) of the plurality of channels (5, 7) .

2. A primary gasket (1) according to the preceding claim, wherein said back portion (3) comprises a connection surface (21) configured to connect the back abutment surface (13) and the inner lip surface (19) , wherein the connection surface (20) forms a curvilinear concave surface on the gasket body (2) , wherein, in each gasket section passing through the axial direction (X-X) and theradial direction (R-R) , the connection surface (21) forms a connection arc (22) preferably an arc of a circumference.

3. A primary gasket (1) according to any one of the preceding claims, wherein said plurality of protuberances (10, 9) and said root edge (15) define a plurality of discharges (8) , wherein each discharge (8) is delimited by each protuberance (10) and one of the first neighboring protuberances (9) of said plurality of protuberances (10, 9) and by a free edge portion (16) of said root edge (15) extending between each protuberance (10) and the first neighboring protuberance (9) , wherein each protuberance (9, 10) comprises a protuberance body (17) projecting at least from said annular root (14) , and a protuberance head (18) connected to said protuberance body (17) , wherein said protuberance head is configured to abut against said second radial seat wall (109) , avoiding said root edge (15) from abutting against said second radial seat wall (109) allowing a fluid to pass through said plurality of discharges (8) .

4. A primary gasket (1) according to claim 1, wherein each protuberance (9, 10) comprises a protuberance body (17) projecting at least from said annular root (14) , and a protuberance head (18) connected to said protuberance body (17) , wherein said protuberance head is configured to abut against said second radial seat wall (109) , avoiding said root edge (15) from abutting againstsaid second radial seat wall (109) .

5. A primary gasket (1) according to any one of claims 3 or 4, wherein said protuberance body (17) and / or each protuberance body (18) is in the shape of a column, preferably cylindrical and / or prismatic .

6. A primary gasket (1) according to any one of claims 3 to 5, wherein said protuberance head (18) and / or each protuberance head (18) is tapered with respect to said protuberance (17) , preferably being rounded in shape in the direction opposite to said annular root such as hemispherical or like a spherical cap, so that it abuts against a circular surface.

7. A primary gasket (1) according to any one of claims 3 to 6, wherein each protuberance body (17) protrudes at least partially in the radial direction (R-R) from the annular root (14) , each forming a rib mainly extending in the axial direction (X-X) along the annular root (14) .

8. A primary gasket (1) according to any one of the preceding claims 3 to 7, wherein each protuberance body (17) projects from said back portion (3) and is at least partially embedded in said annular root (14) , and / or wherein each protuberance body 17 protrudes at least partially in the radialdirection (R-R) with a column-shaped body portion forming a discontinuity circumferentially on the surface of the inner lip (4) facing the outer lip (6) .

9. A primary gasket (1) according to any one of the preceding claims from 3 to 8, wherein each protuberance (9, 10) comprises a protuberance collar (12) connecting the protuberance body (17) and / or the protuberance head (18) to the root edge (15) on the opposite side of the outer lip (6) by tapering in the direction of the protuberance head (18) , preferably wherein each protuberance (9, 10) is configured to compressively work along a direction parallel to the axial direction(X-X) while avoiding bending.

10. A primary gasket (1) according to any one of the preceding claims, comprising at least one of the following features or a combination thereof: wherein said plurality of channels (5, 7) divides said back abutment surface (13) into a plurality of circular abutment sectors (23) , preferably being in the shape of a circular crown arc, wherein each circular abutment sector (23) is configured to abut against the first radial seat wall (108) of said primary gasket seat (105) wherein each circular abutment sector (23) is delimited in the circumferential direction (C-C) by each channel (5) and a first neighboring channel (7) of said plurality of channels (5, 7) , and / or wherein the outer lip surface (20) comprises acircumferential sealing portion (24) extending seamlessly along the circumferential direction (C-C) to form a seal with said axial seat wall (107) , and / or wherein said plurality of channels (5, 7) divides said outer lip surface (20) into a plurality of circumferential sealing sectors (25) , wherein each circumferential sealing sector (25) is configured to form a seal with said axial seat wall (107) , wherein each circumferential sealing sector (25) is delimited along the circumferential direction (C-C) by each channel (5) and a first neighboring channel (7) of said plurality of channels (5, 7) and is connected to the back portion (3) and the circumferential sealing portion (24) .

11. A primary gasket (1) according to the preceding claim, comprising at least one of the following features or a combination thereof : wherein each channel (5, 7) extends along a respective longitudinal channel direction (A-A) from a respective first end (26) on the outer lip (6) to a respective second end (27) , wherein each first end (26) is delimited by the circumferential sealing sector (25) , wherein each second end (27) leads into a connection surface (21) configured to connect the back abutment surface (13) and the inner lip surface (19) so that, in a step of feeding the cylinder assembly (100) , the fluid upstream of the gasket (1) enters into the channel from each second end (27) , flows along each longitudinal channel direction (A-A) and exits from each first end (26) bending the outerlip (6) toward the inner lip (4) , and so that in a step of actuating the cylinder assembly (100) , the fluid downstream of the gasket (1) is prevented from accessing each channel (5, 7) ; and / or wherein each first end (26) is curvilinear, and / or wherein each channel (5, 7) is connected in a curvilinear manner to the respective two circumferential sealing sectors (25) and the respective two circular abutment sectors (23) which delimit the channel (5, 7) , avoiding step-like or undercut connections with the outer lip (6) and / or the back portion (3) ; and / or wherein the gasket (1) comprises a channel surface for each channel (5, 7) , which extends along the respective longitudinal channel direction (A-A) , wherein each channel surface is at least partially cylindrical, avoiding step-like connections with the outer lip (6) and / or the back portion (3) .

12. A primary gasket (1) according to any one of the preceding claims, comprising at least one of the following features or a combination thereof: wherein the number of said plurality of channels (5) is between 10 and 90, preferably between 12 and 30, even more preferably 12, and / or wherein the number of said plurality of protuberances (9, 10) is between 10 and 90, preferably between 12 and 30, even more preferably 12, and / or wherein the number of the channels (5) is equal to the number of the protuberances (9,10) ,and / or wherein said protuberances of said plurality of protuberances (10) are circumferentially equally spaced apart from one another, and / or wherein said channels of said plurality of channels (7) are circumferentially equally spaced apart from one another, and / or wherein each channel (7) is equally spaced apart between each protuberance (9) and the first neighboring protuberance (10) of the plurality of protuberances.

13. A primary gasket (1) for a cylinder assembly (100) , wherein said cylinder assembly (100) comprises a cylinder (101) and a float (102) slidingly housed in a float seat (104) delimited by a cylinder wall (103) of said cylinder (101) for pressurizing a fluid, wherein the primary gasket (1) comprises an annular body (2) extending circumferentially at least along a circumferential direction (C-C) about an axial direction (X-X) , wherein said primary gasket (1) defines a radial direction (R-R) perpendicular to said axial direction (X-X) and said circumferential direction (C-C) , wherein said annular body (2) is configured to be housed in a primary gasket seat (105) defined in said cylinder wall (103) , in which the primary gasket seat (105) is delimited radially by an axial seat wall (107) and axially by a first radial seat wall (108) and a second radial seat wall (109) connected, for example as an undercut, to said axial seat wall (107) , wherein said annular body (2) comprises an inner lip (4) , an outer lip (6) , and a back portion (3) , wherein the back portion (3) comprises a back abutment surface (13)configured to abut against the first radial seat wall (108) of said primary gasket seat (105) , wherein the inner lip (4) and the outer lip (6) extend axially from the back portion (3) , on the opposite side of the back abutment surface (13) , radially spaced apart from each other, wherein the inner lip (4) comprises an inner lip surface (19) configured to form a seal with said float (102) , wherein the outer lip (6) comprises an outer lip surface (20) configured to form a seal with said axial seat wall (107) , wherein the inner lip (4) comprises an annular root (14) extending axially between said back portion (3) and a root edge (15) , wherein the inner lip (4) comprises a plurality of protuberances (9, 10) , wherein each protuberance (9, 10) projects axially from said root edge ( 15) , wherein the gasket (1) delimits a plurality of channels (5, 7) extending on the back portion (3) and at least partially on the outer lip (6) , avoiding abutting against the first radial seat wall (108) of said primary gasket seat (105) and against said axial seat wall (107) , respectively, characterized in that each protuberance (9, 10) protrudes in the axial direction (X-X) from said root edge (15) , and each protuberance (9, 10) protrudes at least partially in the radial direction (R-R) from the annular root (14) from the surface of the inner lip (4) facing the outer lip (6) , each protuberance (9, 10) forming a rib mainly extending in the axial direction (X-X) alongthe annular root (14) .

14. A cylinder assembly (100) for a braking system, comprising- a cylinder (101) wherein said cylinder (101) comprises a cylinder wall (103) internally delimiting a float seat (104) , wherein said cylinder wall (103) delimits a pressure chamber fluidly connectable to a braking device, wherein said cylinder wall (103) delimits a primary gasket seat (105) and a secondary gasket seat (106) , wherein the primary gasket seat (105) is radially delimited by an axial seat wall (107) and axially delimited by a first radial seat wall (108) and a second radial seat wall (109) connected to said axial seat wall (107) , wherein said cylinder (101) defines a feeding conduit (111) fluidly connectable to a reservoir and / or a fluid feeding valve, wherein said feeding conduit (111) leads into a feeding opening (112) on said cylinder wall (103) between said primary gasket seat (105) and said secondary gasket seat (106) ,- a float (102) , wherein the float (102) is slidingly housed in a sealing manner in the float seat (104) to pressurize the fluid in a pressure chamber (110) fluidly connectable to a braking device,- a primary gasket (1) according to any one of the preceding claims, wherein said primary gasket (1) is housed in said primary gasket seat (105) avoiding an axial clearance between said first radial seat wall (108) and said second radial seat wall (109) , wherein eachprotuberance (9, 10) abuts against said second radial seat wall(109) , and wherein said back abutment surface (13) abuts against said first radial seat wall (108) ,- a secondary gasket (115) housed in the secondary gasket seat (106) to form a static and dynamic seal with said float (102) and said cylinder wall (103) .

15. A cylinder assembly (100) according to the preceding claim, wherein said cylinder assembly (100) is a master cylinder.

Images