Brake-system damping device

Abstract

A brake-system damping device includes a first chamber, to which hydraulic pressure is to be applied, a second chamber, in which there is a compressible medium, and a first separating element for separating the first chamber from the second chamber. The brake-system damping device includes a third chamber, in which there is a compressible medium, and a second separating element for separating the second chamber from the third chamber. The second chamber is connected, for medium conduction, to the third chamber by means of a passage formed in the second separating element. A closure element is to be moved with the first separating element, by means of which closure element the passage is to be closed as soon as the hydraulic pressure has reached predefined pressure value in the first chamber.

Claims

1. A brake system damping device comprising: a first chamber, to which hydraulic pressure is applied; a second chamber, in which a compressible medium is situated; a first separating element separating the first chamber from the second chamber; a third chamber, in which the compressible medium is situated; a second separating element separating the second chamber from the third chamber, the second separating element defining at least one passage that connects the second chamber to the third chamber in a medium-conducting manner; a closure element that moves together with the first separating element and is configured to close the passage as soon as the hydraulic pressure in the first chamber reaches a predefined pressure value; and a rib structure having at least one structure rib, which supports the second separating element and extends along an entire axial length of the third chamber, the at least one structure rib circumferentially separating a plurality of subchambers of the third chamber from one another.

2. The brake system damping device as claimed in claim 1, wherein the first separating element is formed in one piece with the closure element.

3. The brake system damping device as claimed in claim 1, wherein the first separating element includes a diaphragm.

4. The brake system damping device as claimed in claim 1, wherein the first separating element is formed of an elastomer.

5. The brake system damping device as claimed in claim 1, wherein the predefined pressure value is between 0 and 30 bar.

6. The brake system damping device as claimed in claim 1, wherein the at least one passage is defined by an open-pore material.

7. The brake system damping device as claimed in claim 1, wherein the at least one passage includes a plurality of passages defined in the second separating element.

8. The brake system damping device as claimed in claim 1, wherein each subchamber of the plurality of subchambers is connected to the second chamber in a medium-conducting manner by a respective passage of the at least one passage.

9. The brake system damping device as claimed in claim 1, wherein the third chamber is defined by the second separating element and a cover.

10. The brake system damping device as claimed in claim 9, wherein the second separating element is completely enclosed by the cover and the first separating element.

11. The brake system damping device as claimed in claim 1, wherein the rib structure defines at least one connecting duct that connects adjacent subchambers of the plurality of subchambers to one another in a medium-conducting manner.

12. The brake system damping device as claimed in claim 1, wherein the rib structure further comprises a rib casing surrounding the at least one structure rib.

13. The brake system damping device as claimed in claim 12, wherein the rib casing defines at least one casing slot extending between a respective subchamber of the plurality of subchambers and a cover that at least partially surrounds the second separating element.

14. The brake system damping device as claimed in claim 12, wherein the rib casing includes at least one latching element.

15. The brake system damping device as claimed in claim 3, wherein the diaphragm is a rolling diaphragm.

16. The brake system damping device as claimed in claim 4, wherein the first separating element is formed of ethylene-propylene-diene rubber.

17. The brake system damping device as claimed in claim 1, wherein the predefined pressure value is between 3 and 10 bar.

18. The brake system damping device as claimed in claim 1, wherein the predefined pressure value is 5 bar.

19. The brake system damping device as claimed in claim 14, wherein the at least one latching element protrudes from an outer wall of the rib casing and is arranged at an end side of the rib structure.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Exemplary embodiments of the solution according to the disclosure will be explained in more detail below on the basis of the appended schematic drawings, in which:

(2) FIG. 1 shows a first exemplary embodiment of a brake system damping device according to the disclosure,

(3) FIG. 2 shows the brake system damping device in FIG. 1 at a first applied hydraulic pressure,

(4) FIG. 3 shows the brake system damping device in FIG. 1 at a second applied hydraulic pressure,

(5) FIG. 4 shows a diagram with characteristic curves relating to the dependency of pressure and volume uptake in brake system damping devices, and

(6) FIG. 5 shows a second exemplary embodiment of a brake system damping device according to the disclosure,

(7) FIG. 6 shows a third exemplary embodiment of a brake system damping device according to the disclosure,

(8) FIG. 7 shows the detail VII from FIG. 6,

(9) FIG. 8 shows a third exemplary embodiment of a brake system damping device according to the disclosure,

(10) FIG. 9 shows the detail IX from FIG. 8.

DETAILED DESCRIPTION

(11) FIG. 1 illustrates a brake system damping device 10 having a housing 12 and a cover 14. In the housing 12 there is arranged a supply line 16 in which there presently prevails no hydraulic pressure, illustrated by means of a scratched arrow 18. The supply line 16 opens into a first chamber 20, which is adjoined by a first separating element 22, here a rolling diaphragm. Behind the first separating element 22 as viewed from the first chamber 20 there is situated a second chamber 24 which is adjoined by a second separating element 26, with a third chamber 28 being situated behind the second separating element 26 in the viewing direction.

(12) In detail, these chambers 20, 24, 28 and separating elements 22, 26 appear as follows. The first chamber 20 is surrounded by a housing inner wall 30 and a first separating element inner wall 32 of the first separating element 22, referred to hereinbelow as rolling diaphragm. Arranged centrally in the separating element 22 and formed in one piece therewith is a closure element 34 from which the separating element 22 extends further outward toward a diaphragm fold 36. A diaphragm fold depression 38 is situated within the diaphragm fold 36 or surrounded thereby. Adjoining the diaphragm fold 36, the separating element 22 extends up to a diaphragm collar 40 which engages around a coupling mount 42 of the housing 12. The separating element 22 configured as a rolling diaphragm has part of its separating element inner wall 32 bearing in a sealing manner against the housing inner wall 30 and has a first separating element outer wall 44 facing the second chamber 24. The second chamber 24 is surrounded by the first separating element outer wall 44 and a second separating element inner wall 46 of the second separating element 26.

(13) The second separating element 26 has a diaphragm holding device 48 extending into the diaphragm fold depression 38. Arranged centrally in the second separating element 26 is a passage 50 which connects the second chamber 24 to the third chamber 28. Here, the passage 50 leads through the second separating element inner wall 46, the second separating element 26 and a second separating element outer wall 52. The third chamber 28 is surrounded by the second separating element outer wall 52 and a cover inner wall 54 of the cover 14.

(14) In the illustrated starting state of the brake system damping device 10 there is initially no hydraulic pressure prevailing in the first chamber 20 in which a braking medium is situated. The separating element 22, which is produced from an elastomer, is situated here substantially in its basic form. Here, it bears against the housing inner wall 30 in such a way that the first chamber 20 is hermetically sealed in relation to the second chamber 24, with a gas, here especially air, being situated in the second chamber 24. This gas is also situated in the third chamber 28, which is connected to the second chamber 24 by means of the passage 50. These two chambers 24, 28 thus form a common gas volume which is available for damping. By virtue of the greater elasticity of this gas volume, a better damping action is achieved when braking or when applying a hydraulic pressure to the first chamber 20.

(15) When a hydraulic pressure prevails in the first chamber 20, the separating element 22 deforms in such a way that the gas volume in the second chamber 24 decreases. Here, the closure element 34 moves into the second chamber 24. Starting from a specific hydraulic pressure which is fixed above a relevant pressure range for damping, the closure element 34 bears against the second separating element inner wall 46 of the second separating element 26 and closes the passage 50 to the third chamber 28. Here, the second separating element 26 acts like a stop. States of the brake system damping device 10 in which the separating element 22 or its closure element 34 bears against the second separating element 26 and closes the passage 50 are illustrated in FIG. 2 and FIG. 3.

(16) By virtue of the closed passage 50, the third chamber 28 is now separated from the second chamber 24, as a result of which only the remaining gas volume in the second chamber 24 can be used for the further damping. The elasticity and damping action is only minor, since the second chamber 24 can barely take up any more volume. This action is intentional, since the travel of a brake pedal connected to the brake system is thus also no longer substantially lengthened. In the state of the brake system damping device 10 as illustrated in FIG. 3, the separating element 22 and the second separating element 26 bear against one another without a gap or with full-surface contact, with the result that the second chamber 24 completely disappears or no longer has any volume. In this case, the travel of the brake pedal no longer lengthens.

(17) As soon as the hydraulic pressure prevailing in the first chamber 20 decreases, the separating element 22 moves back into its starting state or its starting position.

(18) FIG. 2 shows the brake system damping device 10 from FIG. 1, but in a state in which a first hydraulic pressure prevails at the first chamber 20, illustrated by means of an arrow 56 in the region of the supply line 16.

(19) As already mentioned, the closure element 34 bears here against the second separating element inner wall 46 of the second separating element 26 and closes the passage 50 to the third chamber 28. Only the remaining volume in the second chamber 24 can thus be used for the further damping. In the illustration of FIG. 2, this volume is mainly the region around the diaphragm holding device 48. The effects on the damping and the braking operation have already been comprehensively stated in the description pertaining to FIG. 1 and will therefore not be described again here.

(20) FIG. 3 illustrates the brake system damping device 10 from FIG. 1, but in a state in which a second hydraulic pressure prevails at the first chamber 20, illustrated by means of an arrow 58 in the region of the supply line 16.

(21) As already mentioned, the closure element 34 bears against the second separating element inner wall 46 of the second separating element 26 and closes the passage 50 to the third chamber 28. Moreover, the separating element 22 and the second separating element 26 bear against one another without a gap, with the result that the second chamber 24 no longer has any volume. The effects associated therewith on the damping and the braking operation have already been comprehensively stated in the description pertaining to FIG. 1 and will therefore not be described again here.

(22) FIG. 4 shows a diagram relating to the dependency between a pressure 60 and a volume uptake 62 in such brake system damping devices. Here, the pressure 60 is depicted on the x axis and the volume uptake 62 on the y axis. Extending from a coordinate origin of the diagram is a first characteristic curve 64 and a second characteristic curve 66. In addition, the diagram shows a vertical dashed line 68 which intersects the x axis and a horizontal dashed line 70 which intersects the y axis.

(23) The first characteristic curve 64 shows the dependency between pressure and volume uptake for a brake system damping device having a small volume of medium available for the damping. For simplification, the volume of the second chamber 24 in FIG. 1 is to be assumed here for this characteristic curve 64.

(24) The second characteristic curve 66, which extends above the first characteristic curve 64, shows the dependency of pressure and volume uptake for a brake system damping device having in relation thereto a comparatively large volume of medium available for the damping. For simplification, the summed volume of the second and third chamber 24, 28 in FIG. 1 is assumed here for the characteristic curve 66.

(25) The vertical dashed line which intersects the x axis represents a predefined pressure value 68 which forms the upper limit of a pressure range which is relevant for the pulsation damping in such brake systems. This relevant pressure range thus extends from the coordinate origin up to the dashed line.

(26) The horizontal dashed line which intersects the y axis represents a volume stop 70 for the brake system damping device 10 according to the disclosure. This volume stop lies approximately at the volume of the second chamber 24 in FIG. 1.

(27) Corresponding configuration of the respective volumes of the second and third chambers 24, 28 allows the brake system damping device 10 to be tailored to the relevant pressure range and the desired elasticity or damping action in this pressure range. In the case of optimum tailoring, as illustrated in the diagram of FIG. 4, the dashed lines 68, 70 intersect with the characteristic curve 66 at a point.

(28) FIG. 5 illustrates a brake system damping device 10 which differs from the one in FIG. 1 only in the region which is faced by the first separating element outer wall 44 of the first separating element 22 configured as a rolling diaphragm. The separating element 22 itself and the region which is faced by the first separating element inner wall 32 of the separating element 22 completely correspond to FIG. 1 and will not be described again here.

(29) The main difference over the brake system damping device 10 in FIG. 1 is that, instead of the third chamber 28 and the associated passage 50 in FIG. 1, the brake system damping device 10 here in FIG. 5 has a first subchamber 72 with a passage 74 and a second subchamber 76 with a second passage 78. Here, the two subchambers 72, 76 are separated by means of a separating wall 80. A further difference over FIG. 1 is that here in FIG. 5 the second separating element 26 extends up to the housing inner wall 30 and separates the cover 14 therefrom.

(30) All further features correspond to those in FIG. 1. For instance, the second chamber 24 is also surrounded here by the first separating element outer wall 44 and a second separating element inner wall 46 of the second separating element 26. Likewise, the second separating element 26 extends here by way of a diaphragm holding device 48 into the diaphragm fold depression 38 of the separating element 22. Moreover, the subchambers 72, 76 aside from the separating wall 80 are, like the third chamber 28 in FIG. 1, surrounded by the second separating element outer wall 52 and a cover inner wall 54 of the cover 14.

(31) The mode of operation is similar here to that in the brake system damping device 10 in FIG. 1. When a hydraulic pressure prevails in the first chamber 20, the separating element 22 also deforms here in such a way that the gas volume in the second chamber 24 decreases. Here, the closure element 34 moves into the second chamber 24 and, starting from a specific hydraulic pressure which ideally corresponds to the upper limit of the relevant pressure range, bears against the second separating element 26 and closes the passages 74, 78 to the subchambers 72, 76.

(32) As soon as the hydraulic pressure prevailing in the first chamber 20 reduces, the separating element 22 configured as a rolling diaphragm moves back into its starting state or its starting position. As a result, the passages 74, 78 are then opened again, and the subchambers 72, 76 are connected again to the second chamber 24.

(33) FIG. 6 shows a brake system damping device 10 which differs from that in FIG. 1 in the replacement of the cover 14 and in particular in the configuration of the second separating element 26. The remaining components in FIG. 6 correspond to those in FIG. 1 and will not be described again here apart from only this much: in the illustrated state of the brake system damping device 10, no hydraulic pressure 18 at the first chamber 20 prevails at the supply line 16, with the result that the first separating element 22 is situated in a normal shape or starting shape as in FIG. 1. The cover 14 in FIG. 1 is replaced in FIG. 6 by a component 82 having a component outer wall 84 and a component inner wall 86. This component 82 can likewise be used here as a cover. Here, the component 82 bears against the first separating element 22 in such a way that the second separating element 26 is completely enclosed by the component 82 and the first separating element 22. The component inner wall 86 has a depression 88 which runs around the second separating element 26 and which is here arranged at a maximum distance from the first separating element 22. The component outer wall 84 bears against the housing 12 or its housing inner wall 30.

(34) On the side of the separating element inner wall 46, the second separating element 26 is configured substantially in exactly the same way as in the second separating element 26 in FIG. 1. The difference here lies only in that the diaphragm holding device 48 is configured within the diaphragm fold depression 38 to be expanded outwardly in the form of a trumpet or bead or in the direction of the housing inner wall 30, this configuration being referred to here as an outer convexity 90. On the side of the separating element outer wall 52, the second separating element 26 has a rib structure 92 which extends from the separating element outer wall 52 up to a structure end side 94 and thus traverses the entire third chamber 28. The rib structure 92 is configured in one piece with the second separating element 26 and is moreover surrounded by a rib casing 96 having a casing inner wall 98 and a casing outer wall 100. The rib casing 96 extends from the separating element outer wall 52, to be more precise from the diaphragm holding device 48 up to the structure end side 94. On the casing outer wall 100, adjacent to the structure end side 94, there are arranged a plurality of latching elements, with only the latching elements 102 and 104 being visible here, the latching elements being arranged latched in the depression 88.

(35) Within the center of the rib structure 92 there is arranged a circular hollow cylinder 106 with a cylinder cavity 108, which starts at the separating element outer wall 52 in such a way that the passage 50 leads to the cylinder cavity 108. Extending from the circular hollow cylinder 106 up to the rib casing 96 or its casing inner wall 98 are a plurality of structure ribs, of which only the structure ribs 110 and 112 are visible here. The structure ribs 110, 112 divide the third chamber 28 within the ring casing 96 into a plurality of structure subchambers, of which only the structure subchambers 114 and 116 are visible here. The structure chambers are connected to the cylinder cavity 108 by means of connecting ducts, of which only the connecting ducts 118, 120, 122 and 124 are visible here. In this regard, the connecting ducts 118, 120, 122, 124 are arranged at the structure end side 94.

(36) The brake system damping device 10 illustrated here is comparable in its basic mode of operation to the brake system damping device 10 in FIG. 1. It is also the case here for example that the component 82, like the cover 14 in FIG. 1, bears in a stabilizing manner against the first separating element 22. What is additionally presented in this brake system damping device 10 illustrated in FIG. 6 is the supporting function of the rib structure 92, which additionally allows graduated setting of the degree of damping, and the latch-in anchoring of the second separating element 26 in the component 82, here configured as a cover. The supporting effect is achieved by virtue of all the components of the rib structure 92 extending from the separating element outer wall 52 up to the structure end side 94, with the structure end side bearing against the component inner wall 86. The setting of the degree of damping can be carried out by means of closing one or more of the connecting ducts 118, 120, 122, 124 leading to the structure subchambers 114, 116. The latch-in anchoring in the component 82 occurs by means of the latching elements 102, 104. When the second separating element 26 is inserted into the component 82, or when the component 82 is pushed onto the second separating element 26, the latching elements 102, 104 are pressed in inwardly, that is to say into the rib casing 96. As soon as the structure end side 94 has reached the component inner wall 86, the latching elements 102, 104 latch into the depression 88 provided therefor in the component 82.

(37) FIG. 7 illustrates the second separating element 26 from FIG. 6 in perspective as viewed toward the structure end side 94. The rib structure 92 is therefore particularly clearly visible. Also more clearly evident here are the outer convexity 90 and the casing outer wall 100. Apart from the structure ribs 110 and 112 there are now also illustrated the further structure ribs 126, 128, 130 and 132 which extend from the circular hollow cylinder 106 up to the rib casing 96 or its casing inner wall 98. The structure subchambers 114, 116, 134, 136, 138, 140 are arranged between the structure ribs 110, 112, 126, 128, 130, 132 and connected to the cylinder cavity 108 by means of the connecting ducts 118, 120, 122, 124, 142, 144. On the casing outer wall 100 and at the structure end side 94 there are now also illustrated, in addition to the latching elements 102 and 104, the further latching elements 146, 148, 150, 152. Each of these latching elements 102, 104, 146, 148, 150, 152 is arranged adjacent to two of a plurality of casing slots 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176, with the casing slots 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176 extending from the structure end side 94 in the direction of the outer convexity 90.

(38) The components which are newly illustrated here and which match those illustrated in FIG. 6 in terms of nomenclature, such as for example the further latching elements 146, 148, 150, 152, also have the same function. For that reason, such components will not be explained again in terms of their function. Completely newly visible, and therefore not yet described in terms of their functionality, are the casing slots 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176. They fulfill not only the purpose of making additional volume of the third chamber 28 available. In particular, as viewed from the structure end side 94, the casing slots 154, 156, 158, 160, 162, 164, 166, 168, 170, 172, 174, 176 divide up the rib casing 96 in such a way that the latching elements 102, 104, 146, 148, 150, 152 are separated. Depending on the flexibility of the material of the second separating element 26, the regions of the rib casing 96 at which one of the latching elements 102, 104, 146, 148, 150, 152 is arranged can be pressed inwardly with greater or lesser ease. This substantially facilitates the assembly of the second separating element 26 and/or of the component 82 as described in relation to FIG. 6.

(39) FIG. 8 shows a brake system damping device 10 which differs from that in FIG. 6 in the configuration of the component 82 and of the second separating element 26. It is thus also the case here that no hydraulic pressure 18 is applied to the first chamber 20 by means of the supply line 16. As a departure from FIG. 6, here in FIG. 8 the component 82 does not reach, with its component outer wall 84 and component inner wall 86, up to the first separating element 22. There is thus formed a fourth chamber 178 which runs around the second separating element 26 or its rib casing 96. The second separating element 26 here has a support ring 180 which runs around the rib casing 96 and is configured in one piece therewith. The support ring 180 has a ring outer edge 182 and projects into the fourth chamber 178 in such a way that it bears against the first separating element 22, and additionally terminates with the ring outer edge 182 on the housing 12 or the housing inner wall 30. The fourth chamber 178 is thus surrounded or formed by the housing 12, the component 82 and the second separating element 26, or the rib casing 96 and the support ring 180 of the second separating element 26.

(40) The fourth chamber 178 is divided by means of a plurality of ring ribs, of which here only the two ring ribs 184 and 186 are illustrated, into a plurality of ring subchambers, of which here only the ring subchambers 188 and 190 are illustrated. In this case, the ring subchambers 188, 190 are connected to the structure subchambers 114, 116 in a medium-conducting manner by means of the casing slots 154, 156, 166, 168, which are illustrated only in FIGS. 7 and 9. All further components and details in FIG. 8 correspond to those in FIG. 6 and will not be listed again here.

(41) The brake system damping device 10 illustrated here is comparable in its basic mode of operation to the brake system damping device 10 in FIG. 6. However, the component 82 no longer bears here in a stabilizing manner against the first separating element 22. This task is taken over here by the support ring 180 of the second separating element 26. The fourth chamber 178 resulting on account of the smaller or shorter component 82 is now available as additional volume, with the result that a still higher degree of damping of the brake system damping device 10 is achieved. By virtue of the division of the fourth chamber 178 into a plurality of ring subchambers 188, 190, the degree of damping can also be graduated here. In addition, the ring ribs 184, 186 dividing the fourth chamber 178 support the support ring 180 against the component 82.

(42) FIG. 9 illustrates the second separating element 26 from FIG. 8 in perspective. The outer convexity 90 and the casing outer wall 100 of the rib casing 96 are also clearly visible again. The focus in FIG. 9 is in particular on the support ring 180 with its ring outer edge 182 and on the ring ribs arranged on the support ring 180, of which here, in addition to the ring ribs 184 and 186, further ring ribs 192, 194, 196 are illustrated. The rib structure 92 at the structure end side 94 is not clearly visible in the perspective illustrated here, but corresponds to the rib structure 92 in FIG. 7. Clearly visible are the casing slots 156, 158, 160, 162 and 164 in the rib casing 96 that extend from the structure end side 94 in the direction of the support ring 180. The support ring 180 and the ring ribs 184, 186, 192, 194, 196 are arranged on the casing outer wall 100 in such a way that the casing slots 156, 158, 160, 162, 164 reach up closer to the support ring 180 than the ring ribs 184, 186, 192, 194, 196 project from said support ring. It is only thus that ring subchambers, of which here, in addition to the ring subchambers 188 and 190, also further ring subchambers 198, 200, 202, 204 are indicated, are connected in a medium-conducting manner to the structure subchambers 114, 116, 134, 136, 138, 140, which are illustrated only in FIG. 7.

(43) The components which are newly illustrated here and which match those illustrated in FIG. 8 in terms of nomenclature, such as for example the further ring ribs 192, 194, 196, also have the same function. Therefore, such components will not be explained again in terms of their function. Here again newly visible, and therefore not yet described in terms of their functionality in FIG. 8, are the casing slots 154, 156, 158, 160, 162, 164. The remaining casing slots 166, 168, 170, 172, 174, 176 illustrated in FIG. 7 are not illustrated for this embodiment. However, since the second separating element 26 is designed to be symmetrical, an overall picture can be inferred from the visibly illustrated components. Moreover, it can be inferred from FIG. 8 and FIG. 9 in combination how the ring subchambers 188, 190, 198, 200, 202, 204 are connected by means of the casing slots 154, 156, 158, 160, 162, 164 to the ring structure 92 within the rib casing 96.