PRIMARY GASKET FOR A CYLINDER ASSEMBLY, CYLINDER ASSEMBLY

Abstract

The present invention relates to 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 housing (104) delimited by a cylinder wall (103) of said cylinder (101) for pressurizing a fluid, wherein said primary gasket (1) comprises an annular body (2) configured to be accommodated in a primary gasket housing (105) defined in said cylinder wall (103), wherein the primary gasket housing (105) is delimited radially by an axial housing wall (107) and axially by a first radial housing wall (108) and a second radial housing wall (109) connected as an undercut to said axial housing wall (107), wherein said annular body (2) comprises an inner lip (4), a central lip (5), 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 housing wall (108) of said primary gasket housing (105), wherein the inner lip (4), the central lip (5), and the outer lip (6) extend from the back portion (3) in the axial direction (X-X) spaced apart from one another in the radial direction (R-R) from the opposite side of the back abutment surface (13), wherein the inner lip (4) is configured to form a dynamic and static seal on the float (102), wherein the outer lip (6) is configured to form a seal with said axial housing wall (107), wherein the central lip (5) comprises an annular root (14), which extends axially between said back portion (3) and a root edge (15), wherein the central lip (5) comprises a plurality of protuberances (10, 9), wherein each protuberance (10, 9) projects axially from said root edge (15), 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 a first neighboring protuberance (9) thereof of said plurality of protuberances (10, 9) and by a free edge portion of said root edge (15), which extends between each protuberance (10) and the first neighboring protuberance (9) thereof, wherein each protuberance (10, 9) extends circumferentially by one protuberance extension (G), wherein each discharge (8) extends circumferentially by one discharge extension (L), wherein a sum of each discharge extension (L) is greater than a sum of each protuberance extension (G).

Claims

1-10. (canceled)

11. 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 housing (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), which extends 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 accommodated in a primary gasket housing (105) defined in said cylinder wall (103), in which the primary gasket housing (105) is delimited radially by an axial housing wall (107) and axially by a first radial housing wall (108) and a second radial housing wall (109) connected in an undercut manner to said axial housing wall (107), wherein said annular body (2) comprises an inner lip (4), a central lip (5), 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 housing wall (108) of said primary gasket housing (105), wherein the inner lip (4), central lip (5), and outer lip (6) extend axially from the back portion (3), on the side opposite the back abutment surface (13), radially spaced apart from one another, wherein the inner lip (4) is configured to form a seal with said float (102), wherein the outer lip (6) is configured to form a seal with said axial housing wall (107), wherein the central lip (5) comprises an annular root (14), which extends axially between said back portion (3) and a root edge (15), wherein the central lip (5) comprises a plurality of protuberances (10, 9), wherein each protuberance (10, 9) protrudes axially from said root edge (15), 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 its first neighboring protuberances (9) of said plurality of protuberances (10, 9) and by a free portion of the edge of said root edge 15, which extends between each protuberance (10) and its first neighboring protuberance (9), wherein each protuberance (10, 9) extends circumferentially by one protuberance extension (G), wherein each discharge (8) extends circumferentially by one discharge extension (L), wherein a sum of each discharge extension (L) is greater than the sum of each protuberance extension (G).

12. A primary gasket (1) according to claim 11, comprising at least one of the following features or a combination thereof: wherein the sum of each discharge extension (L) is at least two times greater than the sum of each prominence extension (G), and/or wherein the sum of each discharge extension (L) is at least three times greater than the sum of each prominence extension (G), and/or wherein said protuberances of said plurality of protuberances (10) are circumferentially equidistant from one another along said discharge extension (L), and/or wherein each protuberance (10) and each first neighboring protuberance extend circumferentially with said protuberance extension (G).

13. A primary gasket (1) according to claim 12, comprising at least one of the following features or a combination thereof: wherein said discharge extension (L) is equal to at least said protuberance extension (G), and/or wherein said discharge extension (L) is equal to at least twice said protuberance extension (G), and/or wherein said discharge extension (L) is comprised between at least three times said prominence extension (G) and at least five times said prominence extension (G).

14. A primary gasket (1) according to claim 11, comprising at least one of the following features or a combination thereof: wherein each protuberance (9, 10) comprises a protuberance body (17), which protrudes from said annular root (13), and a protuberance head (18) connected to said protuberance body (17), wherein said protuberance head is configured to abut against said second radial housing wall (109), preventing said root edge from abutting against with said second radial housing wall (109) allowing a passage of fluid through said plurality of discharges (8), and/or wherein said annular root (13) has axially a root extension (M) between said back portion (3) and said root edge (15), wherein each protuberance (9, 10) has axially a protuberance axial extension (N) between said root edge (15) and a protuberance end, wherein the axial root extension (M) is comprised between two times the axial protuberance extension (N) and six times the axial protuberance extension (N).

15. A primary gasket (1) according to claim 14, comprising at least one of the following features or a combination thereof: wherein said protuberance body (17) and/or each protuberance body (18) has a cylindrical and/or prismatic shape, and/or wherein said protuberance head (18) is made in one piece with said protuberance body (17); and/or wherein said protuberance head (18) and/or each protuberance head (18) is tapered relative to said protuberance body (17).

16. A primary gasket (1) according to claim 15, wherein said protuberance head (18) and/or protuberance head (18) has a cylindrical shape, wherein said protuberance head (18) and/or each protuberance head (18) has a rounded shape in the direction opposite to said annular root e.g., such as hemispherical or a spherical cap, such that it abuts against a circular surface.

17. A primary gasket (1) according to claim 16, wherein each discharge of said plurality of discharges (8) has a substantially U-shaped profile, and/or wherein said root edge (15) is an annular edge.

18. A primary gasket (1) according to claim 11, comprising at least one of the following features or a combination thereof: wherein the inner lip (4), outer lip (6), and annular root (14) have substantially the same axial dimension in the axial direction (X-X), and/or wherein there are from 10 to 90 of said plurality of protuberances (9, 10), preferably from 20 to 60 protuberances, even more preferably 30 protuberances.

19. A cylinder assembly (100) for a braking system, comprising a cylinder (101) wherein said cylinder (101) comprises a cylinder wall (103), which internally delimits a floating housing (104), wherein said cylinder wall (103) delimits a pressure chamber fluidically connectable to a braking device, wherein said cylinder wall (103) delimits a primary gasket housing (105) and a secondary gasket housing (106), wherein the primary gasket housing (105) is radially delimited by an axial housing wall (107) and axially delimited by a first radial housing wall (108) and a second radial housing wall (109) connected to said axial housing wall (107), wherein said cylinder (101) defines a supply conduit (111) fluidically connectable to a reservoir and/or fluid feeding valve, wherein said supply conduit (111) leads into a supply opening (112) on said cylinder wall (103) between said primary gasket housing (105) and said secondary gasket housing (106), a float (102), wherein the float (102) is slidingly accommodated in a sealing manner in the float housing (104) to pressurize the fluid in a pressure chamber (110) fluidically connectable to a braking device, a primary gasket (1) according to any one of the preceding claims, wherein said primary gasket (1) is accommodated in said primary gasket housing (105) with axial clearance between said first radial housing wall (108) and said second radial housing wall (109), wherein said primary gasket (1) when it abuts against said first radial housing wall (108) is configured to form a seal with said float (102), said primary housing axial wall (107) fluidically isolating the pressure chamber and supply conduit (111), and wherein said primary gasket (1) when it abuts against said second radial wall (109) is configured to form a seal with said float (102) preventing the formation of a seal with said primary housing axial wall (107) to fluidically connect the supply conduit (111) and the pressure chamber (110) to increase the fluid pressure in the pressure chamber, a secondary gasket (115) accommodated in the secondary gasket housing (106) to form a static and dynamic seal with said floating (102) and said cylinder wall (103).

20. A cylinder assembly (100) according to claim 19 wherein said cylinder assembly (100) is a master cylinder or is an actuator for BBW (Brake By Wire) applications.

Description

FIGURES

[0020] 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 non-limiting indication, with reference to the accompanying drawings, in which:

[0021] FIG. 1 is an axonometric view of a primary gasket according to the present invention showing an annular gasket body having an inner lip, an outer lip, and a central lip projecting in an axial direction from a gasket back portion, where the central lip comprises a plurality of protuberances intercalated by a plurality of discharges;

[0022] FIG. 2 is an axonometric view of the primary gasket in FIG. 1 seen from an opposite direction, showing the back portion of the primary gasket;

[0023] FIG. 3 shows a front view of the primary gasket in FIG. 1;

[0024] FIG. 4 shows the gasket in FIG. 1 sectioned along a parallel plane and comprising the radial direction R-R in FIG. 3, in which the central lip is sectioned at a discharge of the plurality of discharges;

[0025] FIG. 5 shows the gasket in FIG. 1 sectioned along a parallel plane and comprising the radial direction R-R shown in FIG. 3, in which the central lip is sectioned at a protuberance of the plurality of protuberances;

[0026] FIG. 6 is an axonometric view of a cylinder assembly according to the present invention, e.g., a brake master cylinder actuatable by a lever to pressurize a fluid, or a linear actuator for BBW (Brake By Wire) systems governed by an electric motor to pressurize a brake fluid;

[0027] FIG. 7 is a section view of the cylinder assembly in FIG. 6 sectioned along a section plane perpendicular to the axial direction X-X and the radial direction R-R, showing the float or piston slidingly accommodated in the float housing made in the sealed cylinder by virtue of the primary gasket in FIG. 1, and a secondary gasket.

DESCRIPTION OF SOME PREFERRED EMBODIMENTS

[0028] 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 accommodated in a float housing 104 delimited by a cylinder wall 103 of said cylinder 101 for pressurizing a fluid. For example, said cylinder assembly 100 is a brake master cylinder or an electrically controlled actuator. According to an embodiment, said electrically controlled actuator is a linear actuator.

[0029] 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.

[0030] Said annular body 2 is configured to be accommodated in a primary gasket housing 105 defined in said cylinder wall 103. The primary gasket housing 105 is delimited radially by an axial housing wall 107 and axially by a first radial housing wall 108 and a second radial housing wall 109, connected as an undercut to said axial housing wall 107.

[0031] Said annular body 2 comprises an inner lip 4, a central lip 5, an outer lip 6, and a back portion 3.

[0032] The back portion 3 comprises a back abutment surface 13 configured to abut against the first radial housing wall 108 of said primary gasket housing 105.

[0033] The inner lip 4, the central lip 5, and the outer lip 6 extend from the back portion 3 in the axial direction X-X spaced from one another in the radial direction R-R from the opposite side of the back abutment surface 13.

[0034] The inner lip 4 is configured to form a dynamic and static seal on the float 102.

[0035] The outer lip 6 is configured to form a seal with said axial housing wall 107.

[0036] The central lip 5 comprises an annular root 14, which extends axially between said back portion 3 and a root edge 15.

[0037] The central lip 5 comprises a plurality of protuberances 10, 9, where each protuberance 10, 9 projects axially from said root edge 15.

[0038] Said plurality of protuberances 10, 9 and said root edge 15 define a plurality of discharges 8.

[0039] Each discharge 8 is delimited circumferentially by each protuberance 10 and a first neighboring protuberance 9 thereof of said plurality of protuberances 10, 9, and axially by a free edge portion of said root edge 15, which extends between each protuberance 10 and the first neighboring protuberance 9 thereof.

[0040] Each protuberance 10, 9 extends circumferentially by a protuberance extension G.

[0041] Each discharge 8 extends circumferentially by a discharge extension L.

[0042] Advantageously, a sum of each discharge extension L is greater than a sum of each protuberance extension G.

[0043] According to an embodiment, the sum of each discharge extension L and each protuberance extension G is equal to the circumferential extension of the root edge 15.

[0044] According to an embodiment, the sum of each discharge extension L is at least two times greater than the sum of each protuberance extension G.

[0045] According to an embodiment, the sum of each discharge extension L is at least three times greater than the sum of each protuberance extension G.

[0046] According to an embodiment, said protuberances of said plurality of protuberances 10 are circumferentially equidistant from one another along said discharge extension L.

[0047] According to an embodiment, each protuberance 10 and each first neighboring protuberance extend circumferentially with said protuberance extension G.

[0048] According to an embodiment, said discharge extension L is equal to at least said protuberance extension G.

[0049] According to an embodiment, said discharge extension L is equal to at least twice said protuberance extension G.

[0050] According to an embodiment, said discharge extension L is between at least three times said protuberance extension G and at least five times said protuberance extension G.

[0051] By virtue of the provision of the sum of discharge extensions being higher than the sum of the protuberance extensions, a high fluid passage is possible when the protuberances 9, 10 abut against the second radial housing wall.

[0052] According to an embodiment, each protuberance 9, 10 comprises a protuberance body 17 projecting from said annular root 13 and a protuberance head 18 connected to said protuberance body 17. Said protuberance head is configured to abut against said second radial housing wall 109, avoiding said root edge from abutting against said second radial housing wall 109 by allowing a passage of fluid through said plurality of discharges 8.

[0053] According to an embodiment, said protuberance extension G is equal to the maximum circumferential dimension of the protuberance body 17 at the connection with the root edge 15.

[0054] According to an embodiment, said discharge extension L is equal to the circumferential distance along said root edge 15 between two first neighboring protuberance bodies.

[0055] According to an embodiment, said annular root 13 axially has a root extension M between said back portion 3 and said root edge 15.

[0056] According to an embodiment, each protuberance 9, 10 axially has an axial protuberance extension N between said root edge 15 and a protuberance end.

[0057] According to an embodiment, the axial root extension M is between two times the axial protuberance extension N and six times the axial protuberance extension N.

[0058] By virtue of the provision of the annular root 14 and protuberances 9, 10 projecting from the root edge 15, said discharges 8 can be made as radial openings having a circumferential extension equal to the discharge extension and an axial extension equal to the axial protuberance extension N, where the radial openings are spaced apart from the back portion 3 by at least the axial root extension M, thus ensuring a high bending resistance for the central lip.

[0059] According to an embodiment, said protuberance body 17 cylindrical and/or prismatic in shape. According to an embodiment, each protuberance body 17 in cylindrical and/or prismatic in shape. According to an embodiment, said protuberance head 18 and/or each protuberance head 18 is tapered with respect to said protuberance body 17.

[0060] According to 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 cylindrical in shape.

[0062] According to an embodiment, said protuberance head 18 and/or each protuberance head 18 has a rounded shape in the opposite direction to said annular root. According to an embodiment, said protuberance head 18 has a hemispherical or spherical cap shape, so as to abut against a circular surface. According to an embodiment, said protuberance head 18 has an apex portion having a partial spherical cap shape connected to a connecting portion having a cone-shaped side wall which tapers from the protuberance body 17 to the apex portion.

[0063] 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 area of the protuberance perpendicularly to the fluid passage direction, allowing a reduction in terms of fluid passage resistance.

[0064] According to an embodiment, each discharge of said plurality of discharges 8 has a substantially U-shaped profile.

[0065] According to an embodiment, said root edge 15 is an annular edge, tapered in axial direction, avoiding comprising flat surfaces perpendicular to the axial direction.

[0066] According to an embodiment, the inner lip 4, the outer lip 6, and the annular root 14 have substantially the same axial dimension in the axial direction X-X.

[0067] According to an embodiment, the number of said plurality of protuberances 9, 10 is between 10 and 100, preferably between 20 and 60, even more preferably 30.

[0068] According to an embodiment, said gasket body is made of polymer material for gaskets, e.g., gasket rubber, preferably EPDM (Ethylene-Propylene Diene Monomer).

[0069] The present invention also relates to a cylinder assembly 100 for a braking system.

[0070] Said cylinder assembly 100 comprises a cylinder 101. Said cylinder 101 comprises a cylinder wall 103 internally delimiting a float housing 104. Said cylinder wall 103 delimits a pressure chamber fluidically connectable to a braking device. Said cylinder wall 103 delimits a primary gasket housing 105 and a secondary gasket housing 106. Said cylinder 101 defines a supply conduit 111 fluidically connectable to a reservoir and/or a fluid feeding valve, where said supply conduit 111 leads into a supply opening 112 on said cylinder wall 103 between said primary gasket housing 105 and said secondary gasket housing 106.

[0071] Said cylinder assembly 100 comprises a float 102. The float 102 is slidingly accommodated in a sealing manner in the float housing 104 to pressurize a fluid in a pressure chamber 110 fluidically connectable to a braking device.

[0072] Said cylinder assembly 100 comprises a primary gasket 1 according to any one of the previously described embodiments. The primary gasket 1 is accommodated in said primary gasket housing 105 with axial clearance between said first radial housing wall 108 and second said radial housing wall 109. When the primary gasket 1 abuts against said first radial housing wall 108, it forms a seal with said float 102 and said axial wall 107 of primary housing thus fluidically isolating the pressure chamber and the supply conduit 111. When the primary gasket 1 abuts against said second radial housing wall 109, it forms a seal with said float 102 avoiding the formation of a seal with the axial wall 107 of the primary housing to fluidically connect the supply conduit 111 and the pressure chamber 110 to increase the fluid pressure.

[0073] Said cylinder assembly 100 comprises a secondary gasket 115 accommodated in the secondary gasket housing 106 to form a static and dynamic seal with said float and said cylinder wall 103.

[0074] According to an embodiment, said secondary gasket 115 is a two-lip gasket.

[0075] According to an embodiment, said cylinder assembly 100 is a brake master cylinder.

[0076] According to an embodiment, said cylinder assembly 100 is an actuator for BBW (Brake By Wire) applications.

[0077] According to an embodiment, said cylinder assembly 100 comprises an actuator motor 113.

[0078] According to an embodiment, said cylinder assembly 100 comprises an elastic element 114 accommodated inside said cylinder 101, which constantly biases said float 102 in the opposite direction to a float advancement direction.

[0079] 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, in the pressure chamber.

[0080] According to an embodiment, the primary gasket 1 is axially movable in the primary gasket housing between a fluid isolation configuration, in which the back portion 3 abuts against the first radial housing wall and the outer lip forms a seal with the axial wall and the inner lip forms a seal with the float 102, and a fluid communication configuration, in which the protuberances 10, 9 abut against the second radial housing wall and the outer lip is spaced apart from the axial wall and the inner lip forms a seal with the float 102.

[0081] 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 supply 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 fluidically isolated from the supply conduit by means of the primary gasket in the fluid isolation configuration, and the float pressurizes the fluid in the pressure chamber. When the fluid in the supply conduit exceeds the fluid pressure in the pressure chamber, the primary gasket switches to the fluid communication configuration, allowing the pressure in the pressure chamber to be increased.

LIST OF REFERENCE SIGNS

[0082] 1 primary gasket [0083] 2 annular body [0084] 3 back portion [0085] 4 inner lip [0086] 5 central lip [0087] 6 outer lip [0088] 7 central lip abutment portion [0089] 8 plurality of discharges [0090] 9 first neighboring protuberance [0091] 10 protuberance [0092] 11 inner lip end [0093] 12 outer lip end [0094] 13 back abutment surface [0095] 14 annular root [0096] 15 root edge [0097] 16 free edge portion [0098] 17 protuberance body [0099] 18 protuberance head [0100] 100 cylinder assembly [0101] 101 cylinder [0102] 102 float [0103] 103 cylinder wall [0104] 104 float housing [0105] 105 primary housing or primary gasket housing [0106] 106 secondary housing or secondary gasket housing [0107] 107 axial wall of primary housing [0108] 108 first radial wall of primary housing [0109] 109 second radial wall of primary housing [0110] 110 pressure chamber [0111] 111 supply conduit [0112] 112 supply opening [0113] 113 actuator motor [0114] 114 elastic element [0115] 115 secondary gasket [0116] X-X axial direction [0117] R-R radial direction [0118] L circumferential discharge extension [0119] G circumferential protuberance extension [0120] N axial protuberance extension [0121] M axial root extension