Dampers for a vehicle

Abstract

Damper (10) for a vehicle, comprising: - a cylinder tube (20) which forms an interior (65) for the movable reception of a piston (62), - an outer tube (40) which is arranged around the cylinder tube (20), - a central tube (30) which is arranged between the cylinder tube (20) and the outer tube (40), - a control unit (50) with a controllable valve, - a central gap (24) between the cylinder tube (20) and the central tube (30) to provide a fluid flow between the interior (65) and the control unit (50), wherein the control unit (50) forms a passage (51) for the fluid at the central gap space (24) in order to adjust a damping property of the damper (10), characterized by that the central tube (30) has an acoustically optimized adaptation to reduce noise generation during fluid flow, wherein the central gap space (24) is formed concentrically around the cylinder tube (20) by the central tube (30) and by the cylinder tube (20), wherein, for acoustically optimized adaptation, an entire circumference of the gap space (24) is subdivided into at least a first circumferential section (36) and a second circumferential section (37) with different gap space widths (25) such that in the first circumferential section (36) the central tube wall thickness (31) is greater than in the second circumferential section (37).

Description

[0001] The present invention relates to a damper of the type defined in more detail in the preamble of claim 1.

[0002] Vehicle dampers are known from the prior art that allow for active or semi-active adjustment of their damping characteristics. This is achieved by controlling the fluid flow between different chambers of the damper (such as a working chamber and a compensation chamber). In this context, it is also said that a characteristic map is used instead of a fixed characteristic curve. The characteristic map thus defines the range within which the adjustment can be made, for example, by a driver's selection. Such a function is used, for example, in adaptive suspension systems. A controllable valve arrangement within the damper can be used for adjustment, influencing the fluid flow between the chambers.

[0003] However, a disadvantage of such dampers has been found to be the potential for acoustic noise to occur under certain circumstances. In particular, noise can arise with certain settings, controllable valve arrangements, or driving situations.

[0004] From DE 11 2008 000 666 T5 a shock absorber with a pressure tube, a piston arrangement, a compensating tube and a central tube is known.

[0005] From DE 11 2013 003 335 T5 a shock absorber with a piston arrangement is known which includes separate flow paths.

[0006] Dampers of this type are known from the documents US 5 901 820 A, DE 10 2015 203 522 A1, DE 10 2010 021 913 A1, DE 10 2012 220 156 A1, WO 2017 / 057 213 A1, DE 10 2011 083 612 A1 and US 4 752 062 A.

[0007] It is an object of the present invention to at least partially reduce the aforementioned disadvantages. In particular, it is an object to propose a simpler and possibly more cost-effective solution for reducing noise in a damper and / or increasing the adjustability of the damping characteristics in the noise-free range.

[0008] The foregoing problem is solved by a damper having the features of claim 1. Further features and details of the invention will become apparent from the respective dependent claims, the description and the drawings.

[0009] The problem is solved in particular by a damper for a vehicle, preferably a shock absorber and / or adjustable damper, preferably for a chassis, comprising several tubes, namely in particular: - a cylindrical tube which forms an interior space for the movable reception of a piston, wherein preferably a fluid, such as a liquid, can be received in the interior space, - an outer tube which is arranged (especially coaxially) around the cylinder tube, - a central tube which is arranged (especially coaxially) between the cylinder tube and the outer tube.

[0010] Furthermore, the damper may have: - a control unit with a controllable valve, in particular an adjustable valve, preferably for controlling a resistance for a fluid flow of the fluid, - a central gap between the cylinder tube and the central tube to provide a fluid flow between the interior and the control unit or the adjusting valve.

[0011] The central gap can advantageously be a cavity for receiving the fluid, formed by the walls of the cylinder tube and the intermediate tube. In other words, the central gap can be located between the outer surface of the cylinder tube wall and the inner surface of the intermediate tube wall ("inner" and "outer" here refer to the direction relative to the interior of the damper). The central gap can extend completely or only partially along the cylinder tube wall. If it extends only partially, the length of the intermediate tube can also be only a fraction of the cylinder tube length, e.g., a maximum of 50%, 70%, or 90%.

[0012] In particular, the length within the scope of this invention refers to an extension along a longitudinal axis of the damper, wherein preferably the longitudinal axis and / or a longitudinal direction runs parallel to a direction of movement of the piston and / or corresponds to the direction with the greatest extension of the damper.

[0013] Furthermore, the control unit offers another advantage: it can incorporate a fluid passage in the central gap chamber to adjust the damping characteristics of the damper (e.g., by regulating the flow through this passage using a valve). The fluid is, for example, an oil or similar substance, which can be at least partially contained within the interior as an oil reservoir and, in particular, displaced by the piston. Since the fluid flows through channels (such as the gap chamber and / or an external chamber) and valves (such as the control unit), especially during damper operation, damping forces can be generated by the resistance encountered by the fluid. In this way, the damper can maintain its damping characteristics, which can then be modified by the control unit (e.g., by increasing or decreasing the flow using the valve).

[0014] Advantageously, the central tube is designed with acoustically optimized features to reduce noise generated during fluid flow (and / or damping adjustment). This enhances the adjustability of the damping characteristics, allowing the damper's operating range to be wider without unwanted noise.

[0015] Preferably, the vehicle can be configured as a motor vehicle and / or passenger vehicle and / or electric vehicle and / or hybrid vehicle. It is further advantageous if the vehicle has at least a semi-active (i.e., possibly also an active) and / or adaptive suspension. A damper according to the invention is preferably configured as a shock absorber, preferably as an adjustable damper. However, two adjustment valves for separate control of compression and rebound are also possible. Furthermore, a damper according to the invention can have at least one valve for adjusting a characteristic curve (i.e., the stiffness or the pressure distribution characteristics), preferably within a characteristic map, of the damper. This valve, in particular the valve of the control unit, is electronically controlled, for example, by the vehicle electronics to influence the fluid flow in the damper.In this way, the damping characteristics of the damper, and thus also of the suspension, can be reliably adjusted to, for example, meet a driver's requirements. The different damping characteristics (or pressure profile characteristics) can be a function of the fluid flow supplied to the valve.

[0016] Advantageously, the damper according to the invention is designed as a hydraulic shock absorber in at least (or more than) a two-tube construction (i.e., also a two-and-a-half-tube or three-tube construction). "Half" tube means that the middle tube may have a shorter longitudinal extent than the cylinder and / or outer tube.

[0017] Thus, according to a further advantage of the damper according to the invention, it is possible for the central tube to extend only partially between the cylinder tube and the outer tube, particularly in a longitudinal direction of the damper (i.e., in the direction of the piston's movement). The damper can be designed such that the acoustic disturbances caused by the fluid flow are shifted to a higher flow range (i.e., according to a stiffer damper) and thus become less noticeable to the human ear. The following measures are conceivable as examples for this adaptation: - The material composition of the pipe can be changed (so that this affects the stiffness, in particular increases the stiffness), and / or - Pipe thickness can be varied as a parameter during hydraulic tuning (so that it affects stiffness, in particular increasing stiffness), and / or - a stepped design of at least one of the pipes can be used.

[0018] Particularly advantageous implementations of these adaptations are described below.

[0019] Optionally, in the damper according to the invention, the control unit is provided to be detachably or permanently connected to the central tube and the outer tube, preferably attached to the central tube and the outer tube, in order to form, in particular, the passage for the fluid transported by the central gap. Furthermore, the control unit can provide an outlet for the fluid to an external space between the central tube and the outer tube. This offers the advantage that the control unit can be used to regulate the fluid flow between the central gap and the external space, thus flexibly influencing the damping characteristics of the damper.

[0020] The connection between the control unit and the central and / or outer tube can optionally be achieved using a non-removable, bonded connection. This ensures a safe and reliable damper design.

[0021] Furthermore, it is advantageous if the central gap is connected to the interior via an inlet, wherein the central tube, as the acoustically optimized adaptation, features a geometric modification and / or a material to increase the stiffness of the central tube, preferably designed to reduce noise generation when fluid flows through the inlet. "Increase" here refers in particular to an increase in stiffness relative to at least one of the other tubes, e.g., the cylinder and / or outer tube. The inlet is formed, for example, as a gap through the central tube and / or the cylinder tube. The inlet can also be formed by other components, e.g., a seal or the like. An example of a geometric modification is an increase in the wall thickness of the central tube (central tube wall thickness).Another way to increase stiffness is to use a suitable material for the central tube. For example, the use of hardened steel for the central tube is conceivable; this material could be harder than the material, especially steel, used for the cylinder tube. Furthermore, the central tube can have a higher stiffness than the cylinder and / or outer tube. This allows for reliable noise optimization.

[0022] Furthermore, within the scope of the invention, it is conceivable that the central tube, as the acoustically optimized adaptation, has a transition section with a diameter that tapers towards the control unit (and / or in the longitudinal direction), thereby reducing the gap width of the central gap while maintaining (at least substantially) the same wall thickness of the central tube. In other words, the diameter in the transition section can taper towards the control unit, so that the gap becomes progressively narrower. This offers the advantage that the tapering reduces noise generation, particularly through the gradual change in pressure conditions during fluid flow. Alternatively or additionally, a transition section with a taper can also be arranged in the area of ​​the control unit's passage.Furthermore, the transition section can alternatively have a taper that runs in a direction opposite to the direction towards the control unit.

[0023] Within the scope of the invention, it can be provided that the central tube, as the acoustically optimized adaptation at one tube end, has a first section and, spaced apart from this, a second section, which are connected to each other by a transition section, wherein preferably a first diameter of the central tube in the first section is at least 5%, at least 10%, at least 20%, or at least 30% larger than a second diameter of the central tube in the second section, and preferably in the transition section the diameter of the central tube transitions (at least partially) continuously from the first to the second diameter. This also reliably achieves noise reduction.

[0024] Furthermore, the central gap is formed concentrically around the central tube and the cylinder tube, preferably for acoustic optimization. The entire circumference of the gap is divided into at least a first circumferential section and a second circumferential section, each with different gap widths, by having a greater wall thickness of the central tube in the first circumferential section than in the second. In other words, the gap width can be greater in a specific angular section (opening angle) of the circumference than in the rest of the circumference. This ensures that the gap is suitable for reliable airflow through the control unit's passage at that opening angle.The narrowing of the gap in the remaining area of ​​the circumference (i.e., in the first circumferential section) can be achieved by reducing the wall thickness of the central tube only in the opening angle (i.e., in the second circumferential section), for example, by milling. This enables a particularly high noise reduction. The reduction in wall thickness can, for example, extend over the entire length of the central tube, or predominantly, or over at least 20%, 40%, 60%, 80%, or 90% of the total length of the central tube. The second circumferential section (with the larger gap width) can also extend completely, predominantly, or over at least 20%, 40%, 60%, 80%, or 90% of the total length of the gap in the longitudinal direction.

[0025] Optionally, the second circumferential section can extend over an angle in the range of 60° to 140°, preferably 90° to 120°. This extension preferably refers to the circumference, i.e., a plane orthogonal to the longitudinal direction. This allows sufficient flow to the control unit, while simultaneously enabling pressure adjustment of the fluid to reduce noise.

[0026] Furthermore, it is advantageous if, within the scope of the invention, the second circumferential section extends at the passage of the control unit in order to provide the fluid flow between the interior and the passage via the gap, in particular to direct the flow to the valve. The valve is, for example, controllable, preferably by the vehicle's electronics, so that a damping characteristic of the damper can be reliably controlled in this way.

[0027] Optionally, it is conceivable that the central gap is designed to guide the fluid only in the second circumferential section and to prevent fluid flow in the remaining section, preferably by forming a channel in the central tube, particularly by milling, in the second circumferential section. In other words, the increased gap width (e.g., by reducing the wall thickness of the central tube in the second circumferential section) can form the channel to reliably allow fluid flow.

[0028] Advantageously, the invention provides that the central tube is designed in an acoustically optimized manner, at least by having a central tube wall thickness that is greater than the cylinder tube wall thickness. This allows for a simple and cost-effective increase in stiffness for noise optimization. Alternatively or additionally, it is possible for the central tube wall thickness to be at least 5%, 10%, 20%, 40%, or 60% greater than the cylinder tube wall thickness to reliably and significantly achieve noise optimization.

[0029] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. The drawings show: Fig. 1 a schematic perspective view of a damper according to the invention, wherein a section of the damper is shown as a schematic longitudinal section, Fig. 2 a schematic perspective view of a damper according to the invention, wherein a section of the damper is shown as a schematic longitudinal section, Fig. 3 a schematic perspective view of a damper according to the invention, wherein a section of the damper is shown as a schematic longitudinal and cross-sectional view, Fig. 4 a schematic perspective representation of a damper according to the invention, wherein a section of the damper is shown as a schematic longitudinal and cross section.

[0030] In the following figures, identical reference numerals are used for the same technical features even for different embodiments.

[0031] In the Fig. Figures 1 to 4 schematically show a damper 10 according to the invention, which is, for example, designed as an adjustable damper 10 and thus enables adjustment of a damping characteristic. A control unit 50 can be provided for this adjustment, which has a controllable valve for this purpose.

[0032] The damper 10 comprises a cylindrical tube 20 as the first tube and an outer tube 40 as the second tube. A third tube can also be added to the damper 10, which serves as a central tube 30 to form a central gap 24. Fig. Figure 1 shows that the central tube 30 has approximately the same length in the longitudinal direction L of the damper 10 as the cylinder and / or outer tube 20, 40. However, it is also possible that the central tube 30 only partially has the same length as the cylinder and / or outer tube 20, 40 (the length corresponding to the longitudinal direction L). For example, the central tube 30, and thus also the gap 24, extends only in the area of ​​a passage 51 of the control unit 50 and ends, for example, in the central area of ​​the damper 10. In this case, a seal can be provided to form a fluid-tight closure of the central tube 30 in the central area.

[0033] It is in Fig. Figure 1 clearly shows that the control unit 50 can be attached to the central and outer tubes 30, 40. The valve is controlled, for example, by the vehicle's electronics, in particular by means of an electrical connection (not shown) between the electronics and the control unit 50. For this purpose, the control unit 50 can have an electrical interface, such as a plug connection.

[0034] To effect the adjustment, it is conceivable that the valve influences a fluid flow within the damper 10. The fluid flow occurs, for example, from an interior space 65, in particular a working space 65, via an inlet 26 into the central gap space 24 to an outer space 34, in particular a compensation space 34, of the damper 10. The fluid passes through the passage 51 of the control unit 50, thus also affecting the valve, which can therefore influence the fluid flow. In other words, the valve is integrated into the fluid connection between the interior space 65 and the outer space 34. The fluid flow is primarily caused by the displacement of the fluid by a piston 62, which is movably mounted in the interior space 65 by a piston rod 61. Preferably, the interior space 65 is formed by the inner side of the cylinder tube 20 and / or the outer space 34 is formed by the central tube 30 and the outer tube 40.

[0035] The section view in Fig. Figure 1 shows a section of the damper 10 highlighted by a rectangle in a longitudinal section. The cylinder tube wall thickness 21 of the cylinder tube 20, the gap width 25 of the central gap 24, the central tube wall thickness 31 of the central tube 30, and the outer space width 35 of the outer space 34 are indicated. It can be seen that the central tube wall thickness 31 is greater than the cylinder tube wall thickness 21 as an acoustically optimized adaptation. Thus, reliable noise optimization can be achieved through a structurally simple and potentially cost-effective geometric measure. The gap width 25 is, for example, in the range of 0.1 mm to 4.0 mm, preferably 0.5 mm to 2.0 mm, more preferably 1.0 mm to 1.4 mm, and particularly preferably substantially 1.2 mm. The central tube wall thickness 31 is... B. in the range of 0.2 mm to 5.0 mm, preferably 1.0 mm to 3.0 mm, preferably 1.5 mm to 2.5 mm, particularly preferably substantially 2.3 mm.The values ​​can vary depending on the basic geometry of the damper and should therefore be considered exemplary. The piston diameters, and thus the geometry of the cylinder tubes, depend, for example, on the modular system.

[0036] In Fig. Figure 2 shows that the central tube 30, as the acoustically optimized adaptation at one tube end, has a first section 71 and, spaced apart from it, a second section 72, which are connected by a transition section 70. In the transition section 70, the diameter of the central tube 30 transitions continuously from the first to the second diameter, with the first and second diameters differing from each other. In this way, a reduction in diameter in the direction L (i.e., the longitudinal direction or in the direction of the control unit 50) is achieved. Furthermore, the transition from the first to the second diameter can cause a narrowing of the central gap 24, so that the gap width 25 in the area of ​​the second section 72 is then, for example, only essentially 0.4 mm. The wall thickness 31 of the central tube can, for example, be essentially 1.18 mm and, in particular, remain constant.

[0037] Fig. 3 and Fig. Figure 4 shows further measures for providing an acoustically optimized adaptation, in which only a portion of the central tube 30 forms a channel for providing a substantial fluid flow. Furthermore, the gap width 25 can be significantly reduced, e.g., to a width in the range of 0 to 0.5 mm, preferably 0.01 to 0.1 mm, more preferably 0.04 to 0.08 mm, and particularly preferably substantially 0.08 mm. For this purpose, the central tube wall thickness 31, as the first thickness 31, can be in the range of 1.0 mm to 5.0 mm, more preferably 1.5 mm to 4.0 mm, more preferably 2.0 mm to 3.0 mm, and particularly preferably substantially 2.3 mm. This prevents the fluid flow at least predominantly in this first circumferential section 36. In the second circumferential section 37, however, a larger gap width (e.g.,The width of the central gap 24 (1.2 mm or at least 0.4 mm) is increased by a second thickness 32 of the wall of the central tube 30, which is between 0.5 and 4 mm, preferably 1.0 and 3 mm, more preferably 1.18 and 2 mm, and most preferably substantially 1.18 mm. (The second thickness 32 is indicated in longitudinal section by a dashed line.) Since the second thickness 32 is thus less than the first thickness 31, the gap width 25 in the second circumferential section 37 is increased. This allows fluid flow in this second circumferential section between the interior 65 and the passage 51.

[0038] In addition to the longitudinal section, the Fig. 3 and Fig. Figure 4 also shows a cross-section through the cylinder tube 20 and the central tube 30. It can be seen that the second circumferential section 37 can be provided in a circumferential region which forms an angle 33 of 90° ( Fig. 3) or 120° ( Fig.4) forms. This enables a reliable flow to the control unit 50 from this second circumferential section 37.

[0039] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention. Reference symbol list 10 dampers, adjustable dampers 20 cylinder tube, first tube 21 Cylinder tube wall thickness 24 medium gap space 25 gap width 26 Admission 30 middle tube, third tube 31 Middle tube wall thickness, first thickness 32 second thickness 33 angles 34 Outdoor space, compensation space 35 Exterior width 36 first section 37 second section 40 outer pipe, second pipe 50 Control unit, adjusting valve 51 Passage 61 Piston rod 62 pistons 65 Interior space, workspace 70 Transition section 71 first section 72 second section

Claims

[1] Damper (10) for a vehicle, comprising: - a cylinder tube (20) which forms an interior space (65) for movably receiving a piston (62), - an outer tube (40) arranged around the cylinder tube (20), - a central tube (30) arranged between the cylinder tube (20) and the outer tube (40), - a control unit (50) with a controllable valve, - a central gap (24) between the cylinder tube (20) and the central tube (30) for providing a fluid flow between the interior space (65) and the control unit (50), wherein the control unit (50) forms a passage (51) for the fluid at the central gap (24) in order to adjust a damping property of the damper (10), characterized by , that the central tube (30) has an acoustically optimized adaptation in order to reduce noise during the fluid flow, wherein the central gap space (24) is formed by the central tube (30) and by the cylinder tube (20) concentrically around the cylinder tube (20), wherein for acoustically optimized adaptation an entire circumference of the gap space (24) is divided into at least a first circumferential section (36) and a second circumferential section (37) with different gap space widths (25) in that the central tube wall thickness (31) is greater in the first circumferential section (36) than in the second circumferential section (37). [2] Damper (10) according to claim 1, characterized by in that the central gap (24) is connected to the interior (65) via an inlet (26), wherein the central tube (30) has, as the acoustically optimized adaptation, a geometric adaptation and / or a material for increasing the rigidity of the central tube (30), which is designed to reduce the noise development when the fluid flows through the inlet (26). [3] Damper (10) according to claim 1 or 2, characterized by that the central tube (30) has, as the acoustically optimized adaptation, a transition section (70) with a diameter tapering in the direction of the control unit (50), whereby a reduction of a gap width (25) of the central gap (24) is formed with a substantially constant center tube wall thickness (31) of the center tube (30). [4] Damper (10) according to one of the preceding claims, characterized bythat the central tube (30) has, as the acoustically optimized adaptation at one tube end, a first section (71) and, at a distance therefrom, a second section (72), which are connected to one another by a transition section (70), wherein a first diameter of the central tube (30) in the first section (71) is at least 5% larger than a second diameter of the central tube (30) in the second section (72), and preferably in the transition section (70) the diameter of the central tube (30) transitions continuously from the first to the second diameter. [5] Damper (10) according to one of the preceding claims, characterized by that the second circumferential section (37) extends over an angle (33) in the range of 60° to 140°, preferably 90° to 120°. [6] Damper (10) according to one of the preceding claims, characterized bythat the second circumferential portion (37) extends at the passage (51) of the control unit (50) in order to provide the fluid flow between the interior space (65) and the passage (51) via the gap space (24), in particular in order to flow to the valve. [7] Damper (10) according to one of the preceding claims, characterized by that the central gap (24) is designed only in the second circumferential section (37) to conduct the fluid and otherwise to prevent fluid flow, wherein for this purpose a channel of the central tube (30) is formed, in particular milled out, in the second circumferential section (37). [8] Damper (10) according to one of the preceding claims, characterized by that the central tube (30) is designed in an acoustically optimized manner at least in that it has a central tube wall thickness (31) which is greater than a cylinder tube wall thickness (21). [9] Damper (10) according to claim 8, characterized bythat the center tube wall thickness (31) is at least 20% or at least 40% or at least 60% greater than the cylinder tube wall thickness (21).

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