Vibration damper for a motor vehicle; motor vehicle with a vibration damper; method for manufacturing a vibration damper

Abstract

Vibration damper (10) for a motor vehicle, comprising: - an outer tube (11) with an inner tube (12), - a coaxial inner tube (13) which is filled or can be filled with a damping fluid and forms an annular gap (15) with the outer tube (11), wherein the inner tube (13) is fluidly connected to the outer tube (11) by at least one bottom valve (14), - a working piston (17) arranged on a piston rod (16), which is arranged to be axially movable in the inner tube (13), - a bottom element (18) for closing a longitudinal end (19) of the outer tube (11) furthest from the piston rod, wherein the bottom element (18) is arranged in the inner space (12) of the outer tube (11) and is pre-tensioned by the inner tube (13) in the direction of the longitudinal end (19) of the outer tube (11) furthest from the piston rod such that the bottom element (18) closes the outer tube (11).

Description

[0001] The invention relates to a vibration damper, a motor vehicle with such a vibration damper and a method for manufacturing such a vibration damper.

[0002] Vibration dampers are commonly used in motor vehicles and in industrial applications to ensure safe and comfortable handling under varying driving conditions caused by irregularities such as uneven surfaces, potholes, or other road surface anomalies. Furthermore, vibration dampers also serve to stabilize vehicles when driving under more extreme conditions, such as off-road.

[0003] Multi-tube vibration dampers, especially twin-tube vibration dampers, are frequently used in motor vehicles. These dampers comprise an outer tube and a coaxial inner tube that can be filled with a damping fluid. A piston rod with a working piston is axially movable within the inner tube.

[0004] Typically, these types of vibration dampers, when installed, are connected to the vehicle body at a longitudinal end near the piston rod and to the steering mechanism of the vehicle's wheel suspension at a longitudinal end furthest from the piston rod. To connect to the steering mechanism, vibration dampers often have a mounting element at the longitudinal end furthest from the piston rod. This mounting element can, for example, be a weld eye, a fork, or a clamp.

[0005] The longitudinal end of the vibration damper furthest from the piston rod, which serves, among other things, for connection to the steering system, is usually closed by a base element that is connected to the outer tube of the vibration damper, for example, by welding. However, a disadvantage is that the welding process can damage the vibration damper, such as material distortion or structural changes in the outer tube. Furthermore, this known method of closing the longitudinal end furthest from the piston rod often limits the connection to the steering system to a single attachment point.

[0006] The invention is therefore based on the objective of providing a vibration damper that can be closed or is closed in such a way that, on the one hand, damage to the vibration damper is avoided and, on the other hand, the vibration damper can be connected to the chassis of a motor vehicle by means of different connecting elements. Furthermore, the invention is based on the objective of providing a motor vehicle with at least one such vibration damper and a method for manufacturing such a vibration damper.

[0007] According to the invention, this problem is solved with regard to the vibration damper by the subject matter of claim 1. With regard to the motor vehicle and the method, the aforementioned problem is solved by the subject matter of claims 10 and 11.

[0008] Specifically, this task is solved by a vibration damper for a motor vehicle, the vibration damper comprising the following: - an outer pipe with an inner pipe space, - a coaxial inner tube which is filled or fillable with a damping fluid and forms an annular gap with the outer tube, wherein the inner tube is fluidly connected to the outer tube by at least one bottom valve, - a working piston arranged on a piston rod, which is axially movable in the inner tube, - a base element for closing a longitudinal end of the outer tube furthest from the piston rod.

[0009] The bottom element is arranged inside the outer tube and is pre-tensioned by the inner tube in the direction of the longitudinal end of the outer tube furthest from the piston rod, such that the bottom element closes the outer tube.

[0010] The invention has several advantages.

[0011] The vibration damper according to the invention can be attached to the steering system of a motor vehicle via the base element using various connection elements. By closing the longitudinal end of the outer tube furthest from the piston rod with the base element, this end can advantageously be designed such that different connection elements can be attached to it. In other words, despite closing the longitudinal end of the outer tube furthest from the piston rod with the base element, there are virtually no restrictions regarding the type of connection the vibration damper can have to the steering system. Possible connection elements include a weld eye, a weld fork, or a clamp connection. The invention is not limited to a single connection element; other connection elements are conceivable.

[0012] A further advantage of the invention is that sealing the outer tube with the base element prevents damage to the vibration damper, particularly to the outer tube. For example, the risk of structural changes or material distortion is reduced. This is preferably achieved by loosely inserting the base element into the outer tube in the installed state and fixing it in place with the inner tube. The inner tube presses or clamps the base element towards the end of the outer tube furthest from the piston rod. This preferably creates a force-fit and / or form-fit connection with the inner and / or outer tube. Material-bonded connections, such as welding, which can lead to damage to the vibration damper, are avoided by sealing the outer tube with the base element according to the invention.

[0013] The base element is easy and reliable to install. Advantageously, the base element is inserted into the inner tube via the piston rod end of the outer tube. The inner tube is then inserted into the outer tube. Pressing the inner tube against the base element pre-tensions it towards the end of the outer tube furthest from the piston rod, the base element is secured in position. Because the base element is loosely inserted into the outer tube, it is also easy to remove.

[0014] Furthermore, the base element ensures a secure and tight seal of the vibration damper. For this purpose, the base element, when installed, is positioned at the end of the inner tube furthest from the piston rod, such that the escape of damping fluid is prevented. Preferably, the base element is shaped to correspond essentially to the longitudinal end of the inner tube furthest from the piston rod. The outer geometry of the base element can essentially correspond to the inner geometry of the longitudinal end of the outer tube furthest from the piston rod, particularly in the contact area between the base element and the outer tube.

[0015] In the vibration damper according to the invention, a further weight saving is achieved through the base element. This allows the longitudinal end of the outer tube furthest from the piston rod to be kept short, which advantageously leads to a reduction in the volume of damping fluid in the vibration damper. This results in both a weight saving and a reduction in the required installation space.

[0016] Advantageous embodiments of the invention are specified in the dependent claims.

[0017] Preferably, the outer tube has a bearing area for the base element facing the interior of the tube, with the base element being supported against this bearing area. This is preferably understood to mean that the bearing area extends into the interior of the outer tube. This advantageously creates an area within the interior of the outer tube on which the base element can rest. The bearing area can be a flat surface or, for example, a groove. In the assembled state, the inner tube preferably pre-tensions the base element towards the longitudinal end of the outer tube furthest from the piston rod, such that the base element is pressed, in particular compressed, against the bearing area. This ensures a secure closure of the outer tube.

[0018] The outer tube can have at least one first hollow cylindrical section and at least one second hollow cylindrical section, wherein the first hollow cylindrical section has a larger diameter, particularly an inner diameter, than the second hollow cylindrical section. This change in diameter, particularly an inner diameter change, from the first hollow cylindrical section to the second hollow cylindrical section creates a step in the interior of the tube, which advantageously serves as a bearing area for the bottom element. In the installed state, the bottom element preferably rests on the step or the transition area from the first hollow cylindrical section to the second hollow cylindrical section. The bearing area can therefore be formed simply, i.e., by changing the inner diameter of the outer tube.

[0019] Furthermore, the base element can have a first cylindrical section, to which a second cylindrical section is attached. This second section is arranged coaxially with the first cylindrical section and has a smaller diameter than the first cylindrical section. In the installed state, the first cylindrical section preferably faces the working piston. The second cylindrical section preferably faces away from the working piston. Advantageously, the base element, or the first and second cylindrical sections of the base element, are shaped essentially corresponding to the end of the tube interior furthest from the piston rod. The external geometry of the first and second cylindrical sections of the base element can essentially correspond to the internal geometry of the first and second hollow cylindrical sections of the outer tube. In this way, a tight seal of the vibration damper is achieved.

[0020] In an advantageous embodiment, the outer diameter of the first cylindrical section of the base element is larger than the inner diameter of the second hollow cylindrical section of the outer tube. This ensures that the base element remains in the required position within the outer tube to seal it. The first cylindrical section of the base element can rest on the bearing surface or shoulder of the outer tube formed by the change in diameter from the first to the second hollow cylindrical section. Furthermore, the base element can only be inserted or removed through the piston rod-side longitudinal end of the outer tube.

[0021] Preferably, the bottom element, in particular the first cylindrical section of the bottom element, has a contact surface for the bottom valve, with the bottom valve being arranged on this contact surface. In the installed state, the bottom valve is preferably arranged on the contact surface such that a fluid connection between the annular gap and the interior of the inner tube is possible.

[0022] The base element, in particular the second cylindrical section of the base element, can have a circumferential groove for receiving a sealing element. The sealing element can be an O-ring. In the installed state, the O-ring is preferably located in the circumferential groove of the base element or the second cylindrical section of the base element. The sealing element, in particular the O-ring, ensures a tight seal at the longitudinal end of the outer tube furthest from the piston rod.

[0023] Furthermore, the outer tube, in particular the second hollow cylindrical section of the outer tube, can have a coupling area for connecting the vibration damper to the chassis of a motor vehicle. The coupling area advantageously allows the vibration damper to be connected to the steering mechanism of the wheel suspension by means of different connecting elements.

[0024] For example, the coupling area can include a weld eye, a weld fork, or a clamping surface. Other connection elements are possible. In particular, the coupling area can be designed to include different connection elements.

[0025] According to dependent claim 9, the invention relates to a motor vehicle with at least one vibration damper according to the invention. Reference is made to the advantages explained in connection with the vibration damper.

[0026] According to dependent claim 10, the invention relates to a method for manufacturing a vibration damper for a motor vehicle. In the method according to the invention, an outer tube with an inner tube is first provided. The bottom element is then inserted into the inner tube of the outer tube to close the longitudinal end of the outer tube furthest from the piston rod. The bottom element is preferably inserted via the longitudinal end of the outer tube on the piston rod side. Subsequently, the inner tube is inserted into the inner tube of the outer tube such that the inner tube is arranged coaxially with the outer tube and is in contact with the bottom element. The inner tube can be in direct or indirect contact with the bottom element, for example via the bottom valve. The inner tube forms an annular gap with the outer tube, which is fluidly connected to the interior of the inner tube via the bottom valve.A locking device is then placed on the piston rod-side longitudinal end of the inner tube in such a way that the bottom element is pre-tensioned by the inner tube towards the longitudinal end of the outer tube furthest from the piston rod, thus sealing the outer tube. Regarding the method for manufacturing the vibration damper, reference is made to the advantages explained in connection with the vibration damper.

[0027] In a further advantageous process step, the piston-side longitudinal end of the outer tube can be deformed in such a way that the vibration damper is closed. This is preferably achieved by the deformed part of the outer tube fixing the closing device in its position on the piston-rod-side longitudinal end of the inner tube. The closing device thereby exerts a preload force on the inner tube, which pushes the base element towards the longitudinal end of the outer tube furthest from the piston rod.

[0028] The invention is explained in more detail below with reference to the accompanying drawings. The illustrated embodiments represent examples of how the vibration damper according to the invention can be designed.

[0029] These show Fig. 1 a half section of a vibration damper according to an embodiment of the invention; and Fig. 2 an enlarged section of a longitudinal end of the vibration damper furthest from the piston rod according to Fig. 1.

[0030] In the following description, the same reference numbers are used for identical or equivalent parts.

[0031] Fig. Figure 1 shows a vibration damper 10 for a motor vehicle according to an embodiment of the invention. The vibration damper 10 is shown in half-section. In the vibration damper 10 according to Fig. 1 is a twin-tube vibration damper 10. The vibration damper 10 has an outer tube 11 with a tube interior 12 and an inner tube 13.

[0032] The inner tube 13 is filled with a damper fluid. The damper fluid can be a liquid or a gas. Hydraulic oil is preferably used as the damper fluid.

[0033] The inner tube is arranged coaxially with the outer tube 11 and forms an annular gap 15 with the outer tube 11. Furthermore, the inner tube 13 is fluidly connected to the outer tube 11 by a bottom valve 14 (see figure). Fig. 1).

[0034] In Fig. Figure 1 shows that the vibration damper 10 has a working piston 17 arranged on a piston rod 16. The piston rod 16 is fixedly attached to the working piston 17. The working piston 17 is guided in the inner tube 13 and is axially movable within it. The working piston 17 divides the interior of the inner tube 13 into a first and a second working chamber 25, 26.

[0035] The first working chamber 25 is located furthest from the piston rod, and the second working chamber 26 is located towards the piston rod. The first working chamber 25 is formed between the working piston 17 and a longitudinal end 19 of the vibration damper 10 located furthest from the piston rod. The second working chamber 26 is formed between the working piston 17 and a longitudinal end 20 of the vibration damper 10 located towards the piston rod.

[0036] In the installed position, the piston rod-side longitudinal end 20 of the outer tube 11 is positioned above the longitudinal end 19 furthest from the piston rod. In the installed state, the piston rod 16 projects beyond the piston rod-side longitudinal end 20 of the outer tube 11.

[0037] During compression, the piston rod 16 of the vibration damper 10 dips into the inner tube 13, thereby moving the working piston 17 towards a longitudinal end 19 of the outer tube 11 furthest from the piston rod. This reduces the size of the first working chamber 25, which is formed between the working piston 17 and the longitudinal end 19 of the outer tube 11 furthest from the piston rod. The damping fluid located in the first working chamber 25 is thereby discharged from it.

[0038] During rebound, the piston rod 16 moves out of the inner tube 13, moving the working piston 17 towards the piston rod end 20 of the outer tube 11. This reduces the size of the second working chamber 26. The damper fluid located in the second working chamber 26 is thereby expelled from it.

[0039] A base element 18 is provided for sealing the longitudinal end 19 of the vibration damper 10 furthest from the piston rod. In its installed state, the base element 18 seals the longitudinal end 19 of the outer tube 11 furthest from the piston rod. This ensures the sealing of the vibration damper 10 and prevents the escape of damping fluid.

[0040] The base element 18 is designed in such a way that it can be inserted into the outer tube 11 via the piston rod-side longitudinal end 20 of the vibration damper 10 and positioned at the piston rod-remote longitudinal end 19 of the outer tube 11.

[0041] The Fig. 1 and Fig. Figure 2 shows that the bottom element 18 is arranged in the inner tube 12 of the outer tube 11. In the installed state, the bottom element 18 is positioned at the longitudinal end 19 of the outer tube 11 furthest from the piston rod. This is achieved by pre-tensioning the bottom element 18 through the inner tube 13 in the direction of the longitudinal end 19 of the outer tube 11 furthest from the piston rod. The inner tube 13 presses the bottom element 18 downwards in its installed position, thus preventing movement of the bottom element 18.

[0042] Fig. Figure 2 illustrates that despite the sealing of the longitudinal end 19 of the vibration damper 10 furthest from the piston rod with the base element 18, there are virtually no restrictions regarding the type of connection of the vibration damper 10 to a steering device of the vehicle's wheel suspension. The longitudinal end 19 furthest from the piston rod can be designed such that different connection elements 27, 28, 29 can be attached to the longitudinal end 19 of the outer tube 11 furthest from the piston rod. Fig. Figure 2 shows that either a welding eye 27, a welding fork 28 or a leg clamp 29 can be attached to the longitudinal end 19 of the outer tube 11 furthest from the piston rod.

[0043] It can be seen that the outer tube 11 has a support area 21 facing the inner tube 12 for the base element 18. In the installed state, the base element 18 is supported by the support area 21. The support area 21 extends into the inner tube 12 of the outer tube 11. The inner tube 13 pre-tensions the base element 18 in the direction of the longitudinal end 19 of the outer tube 11 furthest from the piston rod, thereby pressing the base element 18 against the support area 21.

[0044] The outer tube 11 comprises a first hollow cylindrical section 11a and a second hollow cylindrical section 11b. The first hollow cylindrical section 11a has a larger inner diameter than the second hollow cylindrical section 11b. Fig. 1 and Fig. Figure 2 shows that this change in the inner diameter of the outer tube 11 forms the support area 21 for the base element 18.

[0045] Furthermore, the base element 18 comprises a first cylindrical section 18a and a second cylindrical section 18b. The first cylindrical section 18a has a larger diameter than the second cylindrical section 18b. The first and second cylindrical sections 18a, 18b are arranged coaxially. The second cylindrical section 18b adjoins the first cylindrical section 18a.

[0046] The first cylindrical section 18a of the base element 18 is shaped essentially corresponding to the first hollow cylindrical section 11a of the outer tube 11. The second cylindrical section 18b of the base element 18 is shaped essentially corresponding to the second hollow cylindrical section 11b of the outer tube 11.

[0047] The first cylindrical section 18a of the base element 18, when installed, faces the interior of the tube 12 or the working piston 16. The second cylindrical section 18b of the base element 18, when installed, faces away from the interior of the tube 12 or the working piston 16.

[0048] The outer diameter of the first cylindrical section 18a of the base element 18 is larger than the inner diameter of the second hollow cylindrical section 11b of the outer tube 11. This ensures that the base element 18 is securely positioned in the longitudinal end 19 of the outer tube 11 furthest from the piston rod and cannot be removed through the longitudinal end 19 of the outer tube 11 furthest from the piston rod.

[0049] Fig. Figure 1 shows that the bottom element 18, or more precisely the first cylindrical section 18a of the bottom element 18, has a contact surface 22 for the bottom valve 14. In the installed state, the contact surface 22 faces the inner space 12 of the outer tube 11. The bottom valve 14 rests against the contact surface 22 in such a way that a fluid connection is established between the annular gap 15 and the interior of the inner tube 13.

[0050] The base element 18, or more precisely the second cylindrical section 18b of the base element 18, has a circumferential groove for receiving a sealing element 23. The sealing element 23 is designed as an O-ring 23. In the installed state, the O-ring 23 is positioned in the groove of the base element 18. The sealing element 23, or the O-ring 23, ensures a tight seal of the longitudinal end 19 of the vibration damper 10 furthest from the piston rod.

[0051] Fig. Figure 2 shows that the outer tube 11, or the second hollow cylindrical section 11b of the outer tube 11, has a coupling area 24 for connecting the vibration damper 10 to a chassis of a motor vehicle or to the steering mechanism of the wheel suspension. For example, the coupling area 24 can comprise a weld eye 27, a weld fork 28, or a leg clamp 29 (see Figure 2). Fig. 2).

[0052] The process for manufacturing the vibration damper 10 is described using Fig. 1 explained in more detail. First, the outer tube 11 is provided for a vibration damper 10. The base element is then attached via the in Fig.The upper longitudinal end 20 of the outer tube 11, shown in Figure 1, is inserted into the inner tube 12 at the piston rod end. The base element is guided from the upper longitudinal end 19 to the lower longitudinal end 20 of the outer tube 10 until it abuts or rests against the support area 21 of the outer tube 11. The inner tube 13 is then inserted into the inner tube 12 of the outer tube 11 such that the inner tube 13 is arranged coaxially with the outer tube 11 and is in contact with the base element 18.

[0053] A locking device is then placed on the upper longitudinal end of the inner tube 13. A force is applied to the locking device such that the base element 18 is pre-tensioned by the inner tube 13 towards the lower longitudinal end 19 of the outer tube 11, or pressed against the support area 21 of the outer tube 11. The piston rod-side longitudinal end 20 of the outer tube 11 is then deformed such that a residual pre-tension force remains, which acts on the inner tube 13 in such a way that the base element 18 is pressed downwards, or against the support area 21. This fixes the base element 18 in its position. Reference symbol list 10 vibration dampers 11 Outer pipe 11a first hollow cylindrical section of the outer tube 11b second hollow cylindrical section of the outer tube 12 Inner tube of the outer tube 13 Inner tube 14 Bottom valve 15 annular gap 16 Piston rod 17 working pistons 18 floor elements 18a first cylindrical area of ​​the base element 18b second cylindrical area of ​​the base element 19 Longitudinal end furthest from piston rod 20 piston rod side longitudinal end 21 circulation area 22 Contact area 23 Sealing element 24 coupling area 25 first workroom 26 second workroom 27 sweat eye 28 Welding fork 29 Thigh clamp 30 Locking device

Claims

[1] Vibration damper (10) for a motor vehicle, comprising: - an outer tube (11) with an inner tube (12), - a coaxial inner tube (13) which is filled or can be filled with a damping fluid and forms an annular gap (15) with the outer tube (11), wherein the inner tube (13) is fluidly connected to the outer tube (11) by at least one bottom valve (14), - a working piston (17) arranged on a piston rod (16), which is arranged to be axially movable in the inner tube (13), - a bottom element (18) for closing a longitudinal end (19) of the outer tube (11) furthest from the piston rod, characterized by , that the bottom element (18) is arranged in the inner tube (12) of the outer tube (11) and is pre-tensioned by the inner tube (13) in the direction of the longitudinal end (19) of the outer tube (11) furthest from the piston rod, such that the bottom element (18) closes the outer tube (11). [2] Vibration damper (10) according to claim 1, characterized by, that the outer tube (11) has a support area (21) facing the inner tube space (12) for the base element (18), wherein the base element (18) is supported on the support area (21). [3] Vibration damper (10) according to claim 1 or 2, characterized by , that the outer tube (11) has at least one first hollow cylindrical section (11a) and at least one second hollow cylindrical section (11b), wherein the first hollow cylindrical section (11a) has a larger diameter, in particular inner diameter, than the second hollow cylindrical section (11b). [4] Vibration damper (10) according to any one of the preceding claims, characterized by , that the base element (18) has a first cylindrical area (18a) to which a second cylindrical area (18b) is attached, which is arranged coaxially to the first cylindrical area (18a) and has a smaller diameter than the first cylindrical area (18a). [5] Vibration damper (10) according to claim 4, characterized by , that the outer diameter of the first cylindrical section (18a) of the base element (18) is larger than the inner diameter of the second hollow cylindrical section (11b) of the outer tube (11). [6] Vibration damper (10) according to any one of the preceding claims, characterized by , that the bottom element (18), in particular the first cylindrical area (18a) of the bottom element (18), has a contact surface (20) for the bottom valve (14), wherein the bottom valve (14) is arranged on the contact surface (20). [7] Vibration damper (10) according to any one of the preceding claims, characterized by , that the base element (18), in particular the second cylindrical area (18b) of the base element (18), has a circumferential groove for receiving a sealing element (23). [8] Vibration damper (10) according to any one of the preceding claims, characterized by, that the outer tube (11), in particular the second hollow cylindrical section (11b) of the outer tube (11), has a coupling area (24) for connecting the vibration damper (10) to a chassis of a motor vehicle. [9] Vibration damper (10) according to claim 8, characterized by , that the coupling area (24) includes a welding eye (27), a welding fork (28) or a leg clamp (29). [10] Motor vehicle with at least one vibration damper (10) according to one of the preceding claims. [11] Method for manufacturing a vibration damper (10) for a motor vehicle according to any one of claims 1 to 9, wherein the method comprises at least the following steps: - Providing an outer tube (11) with a tube interior (12), - Inserting a bottom element (18) into the tube interior (12) of the outer tube (11) to close a longitudinal end (19) of the outer tube (11) furthest from the piston rod; - Inserting an inner tube (13) into the tube interior (12) of the outer tube (11) such that the inner tube (13) is arranged coaxially with the outer tube (11) and is in contact with the base element (18), - Placing a locking device (30) on a piston rod-side longitudinal end of the inner tube (13) such that the bottom element (18) is pre-tensioned by the inner tube (13) in the direction of the piston rod-remote longitudinal end (19) of the outer tube (11) such that the bottom element (18) closes the outer tube (11). [12] Method according to claim 11, characterized by that the procedure includes the following step: - Forming a piston rod-side longitudinal end (20) of the outer tube (11) such that the vibration damper (10) is closed.

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