Vibration damper for a hydraulic system

Abstract

Vibration damper (1) for a hydraulic system of a vehicle clutch, comprising a first hydraulic port (11) and a second hydraulic port (12) which are connected to each other by a flow chamber (4) for fluids, and a damping chamber (2) open on one side for receiving a hydraulic medium, wherein • the damping chamber (2) open on one side is defined by an inner side (8) of an outer wall (6) of a sleeve-shaped section (15) of a housing (5), at least one outer side (9) of a wall (7) of an insert (3) and by at least one radially circumferential groove (13) for receiving a sealing medium (14); and • two radial side walls (16) of the groove (13) and the sealing medium (14) abut the inside (8) of the outer wall (6) of the sleeve-shaped section (15) of the housing (5), characterized in that the insert (3) has several locking hooks (23) at an end (22) facing the second hydraulic connection (12), which hold a sleeve (25) on corresponding lugs (27), wherein the sleeve (25) has several radial and spaced-apart projections (26) between which the locking hooks (23) run, so that the sleeve (25) is secured against rotation.

Description

[0001] The present invention relates to a vibration damper for a hydraulic system of a vehicle clutch. In particular, the vibration damper comprises a first hydraulic connection and a second hydraulic connection, which are connected to each other by means of a flow chamber and, optionally, by means of further fluid passages. The vibration damper further comprises a damping chamber open at one end for receiving a hydraulic medium.

[0002] Reducing vibrations in the clutch actuation system is of paramount importance. The driver feels these vibrations as vibrations in the clutch pedal while operating it or while holding it down. Therefore, various components are available, specifically tailored to different vehicles and engine types.

[0003] Clutches in motor vehicles are typically hydraulically actuated. This means that a corresponding actuation impulse, for example, by pressing a clutch pedal, is transmitted to a master cylinder and from there hydraulically to a slave cylinder, which actually engages the clutch, for example, by the slave cylinder axially displacing a release bearing or similar component. Pressure fluctuations during the hydraulic transmission of such impulses are undesirable, as they can lead to a noticeable pulsation of the clutch pedal, especially in manually shifted transmissions, as well as noise when the clutch is engaged, and to an imprecise definition of the clutch's engagement point. To dampen such pressure fluctuations, a damper is installed in the corresponding pressure line from the master cylinder to the slave cylinder. The damping element comprises a housing, a sleeve, and a cover.

[0004] German patent application DE 10 2012 201 275 A1 relates to a damping device for damping unwanted pressure fluctuations in a hydraulic system. A master cylinder and a slave cylinder are connected to each other by means of a pressure line through which fluid flows. A sound-dampening element is combined with a damper arranged in the hydraulic system, which has a housing with a through-opening for the fluid.

[0005] German patent application DE10 2013 217 119 A1 relates to a damping device for damping pressure oscillations within a pressure line of the clutch of a motor vehicle. For this purpose, a damping volume is provided, consisting of a double-walled housing. A sleeve is formed within the housing to accommodate the pressure line. Furthermore, connecting means are provided to form a force-fit and / or positive-locking connection between the pressure line and at least the sleeve or the housing.

[0006] German patent application DE 10 2015 205 063 A1 relates to a damper for a hydraulic line, comprising a housing and a cover. The cover can be connected to the housing in a fluid-tight and tensile-resistant manner, with the cover being sealed against the housing by means of a sealing ring in at least one corresponding groove. The cover is tensile-resistantly connected to the housing by means of a plurality of tensile elements.

[0007] In hydraulic systems, such as hydraulic release and engagement systems or clutch systems, a master cylinder is typically used. This cylinder is actuated by the pedal and, based on the pedal action, transmits hydraulic fluid to a clutch slave cylinder to actuate the clutch. Vibrations are often unavoidable in this process, and these vibrations are frequently noticeable as a vibration in the clutch pedal. To prevent this and thus improve driver comfort, a vibration damper is commonly incorporated into the hydraulic system. This damper often has a variable volume to reduce or eliminate vibrations.To enable adaptability to different systems, it is known to provide vibration dampers of varying lengths in order to change the base volume of the variable volume and thus adjust the vibration behavior. A vibration damper according to the preamble of claim 1 is known from DE 10 2016 210 322 A1. Further prior art is disclosed in DE 10 2016 223 933 A1, US 5 320 203 A, US 4 998 609 A and DE 10 2016 211 545 A1.

[0008] It is therefore the object of the present invention to design a vibration damper which provides adaptability of the vibration damper to the required damping volume and which can be manufactured with simplified production effort.

[0009] This problem is solved according to the invention by a vibration damper for a hydraulic system of a vehicle clutch, comprising the features of claim 1.

[0010] The vibration damper according to the invention for a hydraulic system of a vehicle clutch comprises a first hydraulic connection and a second hydraulic connection. The first hydraulic connection and the second hydraulic connection are connected to each other, among other things, by means of a fluid passage chamber. To dampen the vibrations, the vibration damper has a damping chamber open on one side, which is suitable for receiving a hydraulic medium. The damping chamber open on one side of the vibration damper is defined by an inner side of an outer wall of a sleeve-shaped section of a housing, at least one outer side of a wall of an insert, and by at least one radially circumferential groove for receiving a sealing medium. The at least one groove has two radial side walls that abut the inner side of the outer wall of the sleeve-shaped section of the housing.The sealant (O-ring) located between the two radial side walls forms a seal against the inner surface of the outer wall of a sleeve-shaped section of the housing. A sleeve positioned between the passage chamber and the annular stop of the housing also contributes to the damping chamber.

[0011] It is advantageous that the damping chamber is formed from a one-piece housing and at least one insert that can be slid into the housing. Furthermore, the one-piece housing also incorporates the second hydraulic connection, which offers a manufacturing advantage for the vibration damper, as friction welding is eliminated.

[0012] According to one possible embodiment of the invention, the position of the at least one radially circumferential groove on the insert in the axial direction of the vibration damper can be determined and designed such that the volume of the damping chamber is set by the selected position of the radially circumferential groove. To adjust the volume, it is therefore only necessary to provide different inserts for the housing of the vibration damper, each with the at least one groove formed at different axial positions of the insert. The advantage of this design is that the volume or length of the damping chamber of the vibration damper can be changed easily.

[0013] According to another possible embodiment of the invention, at least two radially circumferential grooves are formed on the outside of the insert. The grooves are arranged offset in the axial direction of the vibration damper or the insert. The required volume of the damping chamber can be adjusted by means of the sealant. For this purpose, the sealant is inserted into one of the at least two grooves of the insert for the vibration damper. The volume or length of the damping chamber of the vibration damper can thus be adjusted very easily. In addition, the number of parts required to implement the various configurations of the vibration damper is also reduced. This also lowers the manufacturing costs for the vibration damper.

[0014] The insert for the vibration damper according to the invention has several locking hooks at one end facing the second hydraulic connection, which hold a sleeve against corresponding lugs on the sleeve. The sleeve connects to the through-chamber. The sleeve has several radially spaced projections between which the locking hooks extend. This arrangement prevents the sleeve from rotating. An annular contact element is inserted into the insert, against which a first end of the sleeve rests. A second end of the sleeve rests against an annular stop of the sleeve-shaped section of the housing when the insert is inserted into the housing. This provides axial fixation of the insert and the sleeve. An outer surface of the sleeve is spaced apart from the inner surface of the sleeve-shaped section of the housing. The sleeve thus also contributes to the length and volume of the damping chamber.

[0015] The vibration damper described above offers significantly simplified adaptability of the damping chamber volume compared to prior art solutions. Specifically, the vibration damper is designed as a so-called coaxial damper, comprising a housing with a through-chamber. This through-chamber is connected to a hydraulic section of the hydraulic actuation system via a first hydraulic port and a second hydraulic port. The damping chamber, open on one side, serves to hold a hydraulic fluid. The through-chamber is thus fluidically connected to the damping chamber, allowing hydraulic fluid flowing through the through-chamber to enter the damping chamber. To the extent that vibrations occur in the hydraulic system, they are transmitted to the damping chamber and can be dampened there. For this purpose, the damping chamber is designed to be elastically deformable.The elastically deformable damping chamber allows for a volume that can be varied by hydraulic pressure when vibrations occur, resulting in damping of the vibrations.

[0016] The invention has the advantage that, in vibration dampers, the volume of the damping chamber itself can be adapted to the required properties for reducing vibrations, without having to keep different vibration dampers on hand.

[0017] The following exemplary embodiments of the invention and its advantages will be explained in more detail with reference to the accompanying figures. The proportions in the figures do not always correspond to the actual proportions, as some shapes are simplified and others are enlarged in relation to other elements for better illustration. The figures show: Fig. 1 a sectional view of a vibration damper according to the state of the art; Fig. 2 a sectional view of a vibration damper according to a possible embodiment of the invention; Fig. 3 a sectional view of a vibration damper according to a further embodiment of the invention with three grooves for sealing media; Fig. 4 a sectional view of the vibration damper according to the embodiment from Fig. 3, wherein the sealant is located in the rear groove; Fig. 5 a sectional view of the vibration damper according to the embodiment from Fig. 3, wherein the sealant is located in the middle groove; and Fig. 6 a sectional view of the vibration damper according to the embodiment shown in Fig. 3, wherein the sealing medium is located in the front groove.

[0018] Identical reference numerals are used for identical or similarly functioning elements of the invention. Furthermore, for the sake of clarity, only those reference numerals necessary for describing the respective figure are shown in the individual figures. The following description refers to two embodiments of the vibration damper according to the invention. However, this should in no way be construed as a limitation of the invention.

[0019] Fig. Figure 1 shows a vibration damper 1 for a hydraulic actuation system of a vehicle clutch. The vibration damper 1 has a housing 5 with a through-chamber 4, wherein the through-chamber 4 can be connected to a hydraulic section of the hydraulic actuation system via a first hydraulic port 11 and a second hydraulic port 12. The housing 5 is double-walled. The housing 5 forms a damping chamber 2, open on one side to the hydraulic section, for receiving a hydraulic medium, wherein the damping chamber 2 is bounded by an outer wall 6 of the housing 5 that is elastically deformable by hydraulic vibrations occurring in the hydraulic section.In the vibration damper 1 shown, a covering 10, which is elastically deformable by hydraulic vibrations occurring in the hydraulic system, is arranged on the outer wall 6 of the housing 5 to at least partially enclose the outer wall 6 of the housing 5. The covering 10 is, for example, designed as heat-shrink tubing.

[0020] Fig. Figure 2 shows a sectional view of a vibration damper 1 according to a possible embodiment of the invention. A first hydraulic connection 11 and a second hydraulic connection 12 are connected to each other via the flow chamber 4. The damping chamber 2, open on one side, serves to receive the hydraulic medium. The damping chamber 2, open on one side, is defined by an inner surface 8 of an outer wall 6 of a sleeve-shaped section 15 of the housing 5, an outer surface 9 of a wall 7 of an insert 3, and by a radially circumferential groove 13 for receiving a sealing agent 14. The damping chamber 2, open on one side, is closed off by two radial side walls 16 of the groove 13 together with the sealing agent 14, which is located in the groove 13. The sealing agent 14 rests against the inner surface 8 of the outer wall 6 of a sleeve-shaped section 15 of the housing 5 and thus seals the damping chamber 2 on one side.

[0021] The volume provided by the damping chamber 2 can be adjusted according to the damping requirements by the position of the radially circumferential groove 13 on the insert 3. To obtain a vibration damper 1 with a damping volume that meets the requirements, it is sufficient to manufacture different inserts 3 for the vibration damper 1, wherein the groove 13 is formed at different positions in the axial direction A of the insert 3. Depending on the required volume of the damping chamber 2, a suitably designed insert 3 is selected. The length L of the damping chamber 2 is measured from the position of the sealing element 14 on the insert 3 to an annular stop 32 of the sleeve-shaped section 15 of the housing 5.

[0022] The insert 3, which encloses the damping chamber 2, has several locking hooks 23 at one end 22 facing the second hydraulic connection 12. A sleeve 25 is held on the insert 3 by the locking hooks 23 via corresponding lugs 27. An annular contact element 30 is inserted into the insert 3, against which a first end 28 of the sleeve 25 rests. A second end 29 of the sleeve 25 rests against the annular stop 32 of the sleeve-shaped section 15 of the housing 5 when the insert 3 is inserted into the housing 5.

[0023] The sleeve 25 is secured against rotation by several radially spaced projections 26 on the sleeve 25. The locking hooks 23 extend between the projections 26, thus securing the sleeve 25 against rotation. The sleeve 25 is fixed in the axial direction A by bearing against the annular contact element 30 and the annular stop 32 of the sleeve-shaped section 15 of the housing 5.

[0024] The sleeve 25 connected to the insert 3 is in fluid communication with the passage chamber 4. The length L of the damping chamber 2 also extends along the sleeve 25.

[0025] With the sectional view of the Fig. Figure 3 shows a vibration damper 1 according to a further embodiment of the invention. The insert 3 has three spaced-apart grooves 13 in the axial direction A, into which a sealing agent 14 (not shown here) can be inserted as desired. Although the following description relates to the Fig. 3 to 6 on three slots 13v, 13 M , 13 H This limitation should not be interpreted as a limitation of the invention. Depending on the length L3 of the insert 3, fewer than two grooves 13 or more than three grooves 13 can be formed on the insert 3. Each of the grooves 13v, 13 M , 13 H has two radial side walls 16 which abut the inside 8 of the outer wall 6 of a sleeve-shaped section 15 of the housing 5 and thus provide central guidance of the insert 3 in the housing 5.

[0026] Fig. Figure 4 shows a sectional view of the vibration damper 1 according to the embodiment shown in Fig. 3, wherein the sealant 14 (O-ring) is in the rear groove 13 H The insert 3 is located. This rear groove 13 H is closest to the first hydraulic connection 11 of the vibration damper 1. This configuration results in a difference compared to the embodiments of the Fig. 5 and Fig. 6 the damping chamber 2 with the greatest length L.

[0027] Fig. Figure 5 shows a sectional view of the vibration damper 1 according to the embodiment shown in Fig. 3, wherein the sealant 14 (O-ring) is in the middle groove 13 M sits. This middle groove 13 M lies between the rear groove 13 H and the front groove 13v of the insert 3 of the vibration damper 1. This configuration results in a difference compared to the embodiments of the Fig. 4 and Fig. 6 the damping chamber 2 with the medium length L.

[0028] Fig. Figure 6 shows a sectional view of the vibration damper 1 according to the embodiment shown in Fig. 3, wherein the sealing medium 14 (O-ring) is located in the front groove 13v. This front groove 13v is closest to the second hydraulic port 12 of the vibration damper 1. This configuration results in, compared to the embodiments of the Fig. 4 and Fig. 5 the damping chamber 2 with the shortest length L.

[0029] Although the description of the invention relates to selected embodiments, this should not be interpreted as a limitation of the invention. It is obvious to a person skilled in the art that modifications and adaptations can be made without departing from the scope of protection defined in the following claims. Reference symbol list 1 vibration damper 2 damping chambers 3 deployment 4 Transit chamber 5 cases 6 Exterior wall 7 Wall 8 Inside 9 Outside 10 Wrapping 11 first hydraulic connection 12 second hydraulic connection 13 Nut 13 H rear groove 13 M middle groove 13v front groove 14 Sealants 15 sleeve-shaped section 16 side wall 22 end facing the second hydraulic connection 23 locking hooks 24 Outside 25 sleeve 26 radial projections 27 Nose 28 first end of the sleeve 29 second end of the sleeve 30 ring-shaped installation element 32 ring-shaped stop A axial direction L Length of the damping chamber L3 Length of deployment

Claims

[1] Vibration damper (1) for a hydraulic system of a vehicle clutch, comprising a first hydraulic port (11) and a second hydraulic port (12) which are connected to each other by a flow chamber (4) for fluids, and a damping chamber (2) open on one side for receiving a hydraulic medium, wherein • the damping chamber (2) open on one side is defined by an inner side (8) of an outer wall (6) of a sleeve-shaped section (15) of a housing (5), at least one outer side (9) of a wall (7) of an insert (3) and by at least one radially circumferential groove (13) for receiving a sealing medium (14); and • two radial side walls (16) of the groove (13) and the sealant (14) abut the inside (8) of the outer wall (6) of the sleeve-shaped section (15) of the housing (5), characterized by, that the insert (3) has several locking hooks (23) at an end (22) facing the second hydraulic connection (12), which hold a sleeve (25) on corresponding lugs (27), wherein the sleeve (25) has several radial and spaced-apart projections (26) between which the locking hooks (23) run, so that the sleeve (25) is secured against rotation. [2] Vibration damper (1) according to claim 1, wherein the housing (5) is designed as a single piece such that it excludes the second hydraulic connection (12). [3] Vibration damper (1) according to one of the preceding claims, wherein the position of the at least one radially circumferential groove (13) on the insert (3) is formed in the axial direction (A) of the vibration damper (1), and a volume of the damping chamber (2) is adjustable by the position of the radially circumferential groove (13). [4] Vibration damper (1) according to one of the preceding claims 1 to 2, wherein at least two radially circumferential grooves (13) are formed on the outside (9) of the insert (3) offset in the axial direction (A) of the vibration damper (1) and a volume of the damping chamber (2) is adjustable by the sealing medium (14) in one of the at least two grooves (13). [5] Vibration damper (1) according to any of the preceding claims, wherein the sealing medium (14) is an O-ring. [6] Vibration damper (1) according to one of the preceding claims, wherein an annular contact element (30) is inserted in the insert (3), on which a first end (28) of the sleeve (25) rests and a second end (29) of the sleeve (25) rests against an annular stop (32) of the sleeve-shaped section (15) of the housing (5) when the insert (3) is inserted into the housing (5). [7] Vibration damper (1) according to one of the preceding claims, wherein an outer surface (24) of the sleeve (25) is spaced apart from the inner surface (8) of the sleeve-shaped section (15) of the housing (5).

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