Housing for a vibration damper, vibration damper and vehicle

Abstract

A housing for a vibration damper for a vehicle is proposed. The housing comprises an inner housing. The inner housing is configured to receive a piston. The housing further comprises a fiber optic sensor. The fiber optic sensor comprises a fiber Bragg grating. The fiber optic sensor is arranged on an outer surface of the inner housing.

Description

[0001] The present invention relates to a housing for a vibration damper, a vibration damper and a vehicle.

[0002] Vibration dampers are crucial components in vehicles. They are mechanically arranged parallel to the suspension in the chassis. Their function is to prevent the vehicle body from rocking and oscillating when stimulated by uneven road surfaces or other driving conditions. They also quickly dampen the vibrations of the wheels and axles caused by the road surface, thus ensuring good wheel grip, i.e., good tracking and braking performance. Piston positioning in a vibration damper plays a pivotal role in damping vibrations. It allows the dampers to be tuned to the specific vibration frequencies and amplitudes encountered in different vehicle applications. The precise positioning of the piston relative to the damper cylinder influences the damper's ability to convert the kinetic energy of the vibrations into heat energy. The piston position in a vibration damper is not typically measured during vehicle operation. Instead, damping performance is assessed based on measurements of vehicle behavior, such as driving dynamics or occupant satisfaction.

[0003] Against this background, it is an object of the present invention to enable improved monitoring of a vibration damper, e.g., improved determination of a position of the piston.

[0004] The object of the invention is achieved by a housing for a vibration damper, a vibration damper, and a vehicle according to the independent claims. Further aspects and developments of the invention are set forth in the dependent claims, the following description, and the figures.

[0005] According to a first aspect of the invention, a housing for a vibration damper for a vehicle is proposed. The housing comprises an inner housing. The inner housing is designed to receive a piston. The housing further comprises a fiber optic sensor. The fiber optic sensor comprises a fiber Bragg grating. The fiber optic sensor is arranged on an outer surface of the inner housing. By arranging the fiber optic sensor on the inner housing, a change in a cross-section of the inner housing can be determined by means of the fiber optic sensor or by means of the fiber Bragg grating. This means that a change in a radial expansion, e.g., an enlargement and / or a reduction in a cross-section, of the inner housing can be determined by an arrangement of the fiber Bragg grating. For example, a piston can be arranged in the inner housing. The piston can lead to a deformation, e.g., a radial enlargement or reduction.Expansion of the inner housing. The radial enlargement or expansion can be determined using the fiber Bragg grating. Accordingly, the position of the piston can be determined using the fiber Bragg grating. The position, i.e., the arrangement, of the fiber Bragg grating can then be used to determine the position of the piston, i.e., the stroke positioning, within the inner housing. This can simplify the determination of the position of a piston.

[0006] In one embodiment, the fiber optic sensor can comprise a plurality of fiber Bragg gratings. The fiber optic sensor can be arranged on the outer surface of the inner housing such that the plurality of fiber Bragg gratings are spaced apart along an axial extent of the inner housing. By using a plurality of fiber Bragg gratings spaced apart from one another along the axial extent, other parameters of a vibration damper can be determined in addition to the stroke positioning. For example, the plurality of fiber Bragg gratings can be used to determine a relative speed of the piston, an internal pressure causing expansion, and / or a set piston force. This allows relevant variables of a vibration damper to be determined in a simplified manner.

[0007] In one embodiment, the plurality of fiber Bragg gratings can be arranged, in particular periodically, at a maximum spacing of 1 mm along the axial extent of the inner housing. By arranging the fiber Bragg gratings at a maximum spacing of 1 mm, relevant parameters such as the relative velocity of the piston and / or a set piston force can be determined more effectively.

[0008] In one embodiment, two of the plurality of fiber Bragg gratings can be arranged radially opposite each other on the inner housing. The radially opposite arrangement can, for example, improve the determination of the stroke positioning.

[0009] In one embodiment, the housing may further comprise a second fiber optic sensor. The second fiber optic sensor may comprise a fiber Bragg grating. The second fiber optic sensor may be arranged along an axial extent of the inner housing at a distance from the inner housing. That is, the second fiber optic sensor may be arranged such that a change in a cross-section of the inner housing has no influence on the second fiber optic sensor. Accordingly, the second fiber optic sensor may be used to determine a system variable, such as a temperature or pressure, independently of a deformation of the inner housing.

[0010] In one embodiment, the housing may further comprise an outer housing. The outer housing may at least partially surround the fiber optic sensor. The outer housing thus allows the fiber optic sensor to be tuned to an environment.

[0011] In one embodiment, the housing may further comprise a third fiber optic sensor. The third fiber optic sensor may comprise a fiber Bragg grating. The third fiber optic sensor may be arranged on an outer surface of the inner housing. Thus, the third fiber optic sensor may be used in conjunction with the fiber optic sensor to determine a parameter of the piston, for example, a stroke positioning and / or a relative speed of the piston.

[0012] According to a second aspect of the invention, a vibration damper for a vehicle is proposed. The vibration damper comprises a housing as described above and a piston. The piston is arranged within the inner casing of the housing. By using the housing, a parameter of the vibration damper can be determined more effectively.

[0013] In one embodiment, the vibration damper may further comprise a device. The device may comprise an interface and a data processing circuit. The device may be configured to receive sensor data from a fiber optic sensor and to determine a parameter of the vibration damper. The parameter may be a stroke positioning, a relative piston speed, internal pressures causing expansion, and / or a set piston force. This means that the vibration damper may comprise a device configured to evaluate sensor data from the fiber optic sensor. Accordingly, relevant parameters for the vibration damper may be determined by a device integrated into the vibration damper. For example, the device may be arranged within an outer housing of the housing.

[0014] According to a third aspect of the invention, a vehicle is proposed. The vehicle comprises a housing as described above or a vibration damper as described above.

[0015] The present invention will be described below by way of example only with reference to the accompanying figures. They show: Fig. 1a and Fig. 1b show schematic representations of housings for a vibration damper for a vehicle; Fig. 2 shows a schematic representation of an embodiment of a vibration damper; Fig. 3 shows a schematic representation of another embodiment of a vibration damper; Fig. 4 shows a schematic representation of another embodiment of a vibration damper; Fig. 5 shows a schematic representation of an embodiment of a twin-tube vibration damper comprising a housing according to the invention; and Fig. 6 shows an embodiment of a vehicle.

[0016] Fig. 1a and Fig. 1b show schematic representations of housings 100a, 100b for a vibration damper for a vehicle. As in Fig. As shown in Figure 1a, the housing 100 includes an inner housing 110. The inner housing 110 is configured to receive a piston (not shown). Furthermore, the housing 100 includes a fiber optic sensor 120. The fiber optic sensor 120 includes a fiber Bragg grating 122. The fiber optic sensor 120 is disposed on an outer surface 112 of the inner housing 110.

[0017] In a fiber optic sensor, a glass fiber can serve as a measuring transducer. For this purpose, an optical interference filter, a fiber Bragg grating, can be integrated, for example, by inscription, into the glass fiber. The fiber Bragg grating can filter certain spectral components of the light from a spectrum. Due to external influences, such as temperature or stress, a fiber Bragg grating integrated into the glass fiber can be subjected to strain. This change in the distance of the fiber Bragg grating can lead to a shift in the filter spectrum. On this basis, a variable causing the shift can be determined. This means that the fiber optic sensor 120 comprising the fiber Bragg grating 122 can be used to determine an external influence (e.g., a temperature change, a pressure change, a stress) acting on the fiber optic sensor 120 or the fiber Bragg grating 122.

[0018] By arranging the fiber optic sensor 120 on the outer surface 112 of the inner housing 110, a change in a dimension of the inner housing 110 can result in a force being transmitted to the fiber optic sensor 120. This means that the fiber optic sensor 120 or the fiber Bragg grating 122 can be used to determine a change in a parameter of the inner housing 110.

[0019] As in Fig. 1a, the fiber optic sensor 120 can be arranged at least partially radially circumferentially around the inner housing 110. In this case, the fiber optic sensor 120 can be used in particular to determine a change in a radial extent of the inner housing 110. Optionally or alternatively, the fiber optic sensor 120b can be arranged as in Fig. 1b, the housing 100b can be arranged at least partially along an axial extension of the inner housing 110. In this case, the fiber optic sensor 120b, i.e., the fiber Bragg grating 122b, can be used in particular to determine a change in the longitudinal direction of the housing 120b.

[0020] For example, a piston comprising a piston ring can be arranged in the housing. The piston ring can lead to an expansion of the inner housing 110. This means that the inner housing can have a larger cross-sectional area in a region where the piston is arranged than in a region where the piston is not arranged. The piston can therefore cause a radial expansion of the inner housing 110. Accordingly, an expansion of the inner housing 110 by the piston can lead to an external influence that can be determined using the fiber Bragg grating 122. For example, if the position of the fiber Bragg grating 122 relative to the inner housing 110 is known, a stroke positioning (i.e., a position of the piston) within the housing 100 can be determined. The use of the fiber optic sensor 120 can therefore improve the determination of the stroke positioning.In particular, the stroke positioning can be determined with only one fiber optic sensor 120 comprising only one fiber Bragg grating 122.

[0021] An arrangement of the fiber optic sensor 120 on the outer surface 112 of the inner housing 110 can be at least partially positively, non-positively, and / or firmly bonded. For example, the fiber optic sensor can be at least partially wound onto the inner housing 110 under pretension, resulting in a non-positive contact between the inner housing 110 and the fiber optic sensor 120. For example, the fiber optic sensor 120 can be connected to the inner housing 110 by means of an adhesive.

[0022] For example, the fiber optic sensor 120 can be connected to the inner housing by a positive fit combined with a frictional fit. The fiber optic sensor can be arranged in, on, or at an outer housing, e.g., a hollow cylinder, possibly slotted. The inner housing can then be inserted into the outer housing as a press fit.

[0023] For example, the fiber optic sensor 120 can be in direct contact with the inner housing 110, thereby creating a positive connection between the inner housing 110 and the fiber optic sensor 120. Alternatively, the fiber optic sensor 120 can be spaced from the inner housing 110 only so far that a change in a radial dimension of the inner housing 110 results in a force acting on the fiber optic sensor 120. This means that the fiber optic sensor cannot be arranged directly on the inner housing 110, i.e., cannot be positively connected to the inner housing 110. The fiber optic sensor can be arranged such that a force transmission from the inner housing 110 to the fiber optic sensor 120 is possible. That is, the fiber optic sensor 120 may be arranged separately from the inner housing 110, but may be directly influenced by a change in a radial dimension of the inner housing 110.For example, a distance between the fiber optic sensor 120 and the inner housing 110 may be less than a maximum possible change in the radial dimension of the inner housing 110 during operation of a vibration damper.

[0024] In one embodiment, the fiber optic sensor 120 can comprise a plurality of fiber Bragg gratings. The fiber optic sensor 120 can be arranged on the outer surface of the inner housing 110 such that the plurality of fiber Bragg gratings are spaced apart along an axial extent of the inner housing 110. By arranging a plurality of fiber Bragg gratings, in addition to the stroke positioning, further parameters of the piston or the vibration damper can be determined. For example, a relative speed of the piston, an internal pressure causing expansion, and / or a set piston force can be determined. Optionally or alternatively, a conclusion regarding noise, vibration, and / or roughness (NVH) can be drawn by means of corresponding vibration measurements on the vibration damper or the housing 100.Optionally or alternatively, condition monitoring can be carried out using the fiber optic sensor 120.

[0025] The inventors have discovered that various parameters of a vibration damper can be advantageously determined using a housing 100 according to the invention. With the aid of the housing 100, a vibration damper speed can be determined from the position change over time. With the aid of a piston position signal, i.e. based on the determination of a piston position, a piston level can be controlled, for example by means of air spring control. Furthermore, the housing 100 can also be used to determine internal pressures of a vibration damper. Based on the state variables determined using the housing 100, a corresponding control system (control algorithm, EE architecture) can control the associated adjustable vibration dampers. Condition monitoring can also be carried out for all vibration dampers. Optionally or alternatively, the data from a housing 100 can be used and / or further used for other systems.

[0026] In one embodiment, the plurality of fiber Bragg gratings can be arranged at a maximum distance of 0.1 mm, or a maximum of 0.5 mm, or a maximum of 1 mm, or a maximum of 2 mm, or a maximum of 4 mm, or a maximum of 7 mm, or a maximum of 10 mm along the axial extent of the inner housing 110. In particular, the maximum distance between adjacent fiber Bragg gratings can be adapted to an application of the housing 100. In principle, a smaller distance between adjacent fiber Bragg gratings can lead to an improved determination of a parameter. The plurality of fiber Bragg gratings can, in particular, be arranged at a periodic distance.

[0027] A minimum spacing between adjacent fiber Bragg gratings along the axial extent of the inner housing 110 can be determined by a design of the fiber optic sensor 120 and / or the inner housing 110. For example, the fiber optic sensor 120 can be arranged substantially parallel to a longitudinal extent of the inner housing 110. In this case, a spacing between adjacent fiber Bragg gratings along the axial extent of the inner housing 110 can result from a spacing between adjacent fiber Bragg gratings within the fiber optic sensor 120.

[0028] Alternatively, the fiber optic sensor 120 can be arranged, for example wound, at least partially circumferentially around the inner housing 110. This means that a distance between adjacent fiber Bragg gratings can depend on a winding, i.e., a pitch of the fiber optic sensor 120 around the inner housing 110, and a circumference of the inner housing 110. For example, the fiber optic sensor 120 can be configured such that, when wound around the inner housing 110, it is arranged such that fiber Bragg gratings of the fiber optic sensor 120 are arranged adjacent to one another. This means that the distance between adjacent fiber Bragg gratings along the axial extent can be defined by a diameter of the fiber optic sensor 120. In this case, individual turns of the fiber optic sensor 120, which is wound around the inner housing 110, can abut one another.

[0029] In one embodiment, two fiber Bragg gratings of the plurality of fiber Bragg gratings may be arranged radially opposite one another on the inner housing 110. The radially opposite arrangement may improve the determination of a parameter.

[0030] In one embodiment, the housing 100 may further include a second fiber optic sensor. The second fiber optic sensor may include a fiber Bragg grating. The second fiber optic sensor may be spaced apart from the inner housing 110 along an axial extent of the inner housing 110.

[0031] The second fiber optic sensor cannot be in contact with the inner housing 110. As a result, a change in a radial dimension of the inner housing 110 cannot have a direct influence on the second fiber optic sensor. For example, the second fiber optic sensor cannot be influenced by a piston arranged in the inner housing 110. This means that the second fiber optic sensor cannot be influenced by a change in a dimension of the inner housing 110. Accordingly, the second fiber optic sensor can be used to determine a quantity independent of a radial dimension of the inner housing 110.

[0032] For example, the second fiber optic sensor can be used to determine a temperature and / or pressure in an environment of the inner housing 110. The temperature and / or pressure can be used as a reference value, for example, to correct a measured value of the fiber optic sensor (also referred to as the first fiber optic sensor). For example, the inner housing 110 (and the second fiber optic sensor) can be enclosed by an outer housing. This means that the outer housing can form an at least partially enclosed space around the inner housing 110 and the second fiber optic sensor. A change in temperature and / or pressure within this at least partially enclosed space can be determined by the second fiber optic sensor. This makes it possible to determine information about an environment of the inner housing 110 or the (first) fiber optic sensor 120.

[0033] For example, the housing 100 may heat up during operation of a vibration damper. The heating of the housing 100 may cause an external influence on the first fiber optic sensor, for example, a temperature increase. The temperature increase of the housing 100 may lead to a change in the measurement data of the first fiber optic sensor. To correct the temperature increase, the second fiber optic sensor can be used to determine a reference value. Optionally, the second fiber optic sensor can comprise a plurality of fiber Bragg gratings, so that a temperature gradient (and / or pressure gradient) for the housing 100 or a medium within the housing 100, e.g., in the at least partially enclosed space, can be determined.

[0034] The second fiber optic sensor can be included in the first fiber optic sensor 120. That is, the first fiber optic sensor 120 and the second fiber optic sensor can be formed integrally. Alternatively, the second fiber optic sensor can be formed separately from the first fiber optic sensor 120. That is, the first fiber optic sensor 120 and the second fiber optic sensor can be two different fiber optic sensors. The second fiber optic sensor can be arranged parallel to the first fiber optic sensor 120. Optionally or alternatively, the plurality of fiber Bragg gratings of the second fiber optic sensor can be arranged parallel to the plurality of fiber Bragg gratings of the first fiber optic sensor 120. In this case, a temperature gradient can be advantageously determined for a specific arrangement of the fiber Bragg gratings of the first fiber optic sensor 120.

[0035] In one embodiment, the housing 100 may further comprise an outer housing. The outer housing may at least partially surround the fiber optic sensor. The outer housing may therefore allow the fiber optic sensor to be tuned to an environment. The outer housing may at least partially surround the second fiber optic sensor. In particular, the outer housing may form an at least partially enclosed space around the inner housing 110. The fiber optic sensor 120 and / or the second fiber optic sensor may be at least partially disposed within this enclosed space. That is, at least a portion of the fiber optic sensor 120 and / or the second fiber optic sensor may be disposed between the inner housing 110 and the outer housing.

[0036] In one embodiment, the housing 100 may further include a third fiber optic sensor. The third fiber optic sensor may include a fiber Bragg grating. The third fiber optic sensor may be disposed on an outer surface 112 of the inner housing 110. For example, the third fiber optic sensor may be disposed opposite the first fiber optic sensor 120. For example, the third fiber optic sensor may be disposed diametrically opposite the first fiber optic sensor 120 on the outer surface 112. The third fiber optic sensor may be separate from the first fiber optic sensor 120. That is, the third fiber optic sensor and the first fiber optic sensor 120 may be different fiber optic sensors.

[0037] Optionally or alternatively, the third fiber optic sensor can be arranged at least partially circumferentially around the inner housing 110. For example, the third fiber optic sensor can be arranged at least partially circumferentially in a first region of the inner housing 110, for example, an upper region, and the first fiber optic sensor 120 can be arranged at least partially circumferentially in a second region of the inner housing 110, for example, a lower region. This means that the first fiber optic sensor 120 and the third fiber optic sensor can be arranged in different regions of the inner housing 110.

[0038] Fig. 2 shows a schematic representation of an embodiment of a vibration damper 202. The vibration damper 202 comprises a housing as described with reference to Fig. 1 and a piston 230. The piston 230 is disposed within the inner housing 110 of the housing. The piston 230 includes a piston ring 232. Although the piston ring 232 is shown as part of the vibration damper 202, the piston ring 232 is an optional component. That is, the piston 230 may not include a piston ring 232.

[0039] As in Fig. 2, the piston 230 or the piston ring 232 can lead to an expansion of the inner housing 110. This means that the inner housing 110 can have an enlarged cross-section, for example an outer diameter, at a position of the piston 230. Due to the enlarged outer diameter, a force can be transmitted to the fiber optic sensor 120. For example, as in Fig. 2, the fiber optic sensor 120 can be deformed. The deformation of the fiber optic sensor 120 can exert a force on the fiber Bragg grating 122. This means that if the fiber Bragg grating 122 is arranged at a position on the inner housing 110 where a deformation of the inner housing 110 occurs, a measurement indicative of this deformation can be performed. The fiber Bragg grating 122 can be used to determine sensor data for this position of the inner housing 110. By knowing the position of the fiber Bragg grating 122, a position of the piston 230, i.e., a stroke positioning, can then be determined.

[0040] The stroke positioning can be determined, for example, by means of a device that can be included in the vibration damper 202. For example, a first radial deformation caused by a piston can differ from a second radial deformation caused by an internal pressure. The first radial deformation can, for example, be greater than the second radial deformation. That is, a maximum change in the radial dimension can be greater for the first radial deformation than for the second radial deformation. For example, a profile of the first radial deformation can be different from a profile of the second radial deformation. That is, a gradient of the first radial deformation can be greater than a gradient of the second radial deformation. Based on a change in the radial dimension and / or a gradient of the radial, a determination of a piston position (as opposed to a change, for example,by internal pressure).

[0041] In one embodiment, the vibration damper 202 may further comprise a device. The device may comprise an interface and a data processing circuit. The device may be configured to receive sensor data from a fiber optic sensor 120 and to determine a parameter, e.g., a state variable or a parameter dependent thereon, of the vibration damper 202. The parameter may, for example, be a stroke positioning, a relative piston speed, an internal pressure causing expansion, and / or a set piston force. This means that the vibration damper may comprise a device configured to evaluate sensor data from the fiber optic sensor 120. The device may be a component of the housing. Alternatively, the device may be configured separately from the housing, for example, as part of the vibration damper 202 or separately from the vibration damper.This can simplify the replacement of the device.

[0042] The interface may, for example, correspond to one or more inputs and / or one or more outputs for receiving and / or transmitting information, for example in digital bit values, based on a code, within a module, between modules, or between modules of different entities. The interface may, for example, be designed to communicate with other network components via a (radio) network or a local connection network. In embodiments, the data processing circuit may correspond to any controller or processor or a programmable hardware component. For example, the data processing circuit may also be implemented as software that is programmed for a corresponding hardware component. In this respect, the data processing circuit may be implemented as programmable hardware with appropriately adapted software.Any processors, such as digital signal processors (DSPs), can be used. Embodiments are not limited to a specific type of processor. Any processor or even multiple processors are conceivable for implementing the data processing circuit. The interface can be coupled to the respective data processing circuit of the device 250. In examples, the device 250 can be implemented by one or more processing units, one or more processing devices, any means for processing, such as a processor, a computer, or a programmable hardware component that can be operated with appropriately adapted software. Likewise, the described functions of the data processing circuit can also be implemented in software, which is then executed on one or more programmable hardware components.Such hardware components may be a general-purpose processor, a digital signal processor (DSP), a microcontroller, etc. The data processing circuitry may be capable of controlling the interface so that any data transfer occurring over the interface and / or any interaction in which the interface may be involved may be controlled by the data processing circuitry. In one embodiment, the device 250 may include a memory and at least one data processing circuit operably coupled to the memory and configured to perform the method described below. In examples, the interface may correspond to any means for obtaining, receiving, transmitting, or providing analog or digital signals or information, e.g., any terminal, contact, pin, register, input terminal, output terminal, conductor, trace, etc.that enables the provision or receipt of a signal or information. The interface may be wireless or wired and may be configured to communicate with other internal or external components, e.g., to send or receive signals or information. Device 250 may be a computer, a processor, a controller, a field-programmable logic array (FPLA), a field-programmable gate array (FPGA), a graphics processing unit (GPU), an application-specific integrated circuit (ASIC), an integrated circuit (IC), or a system-on-a-chip (SoC).

[0043] Fig. 3 shows a schematic representation of another embodiment of a vibration damper 302. The vibration damper 302 comprises a housing 300 with an inner housing 310 and a fiber optic sensor 320. The vibration damper 302 further comprises a device 350. The device 350 can be configured to receive and process sensor data from the fiber optic sensor 320. The vibration damper 302 further comprises a piston 330 comprising a piston ring 332. Fig. 3 shows a vibration damper in the stationary state.

[0044] The piston 320, together with the piston ring 332, is arranged in the inner housing 310, for example, a cylinder tube 310. A fiber optic sensor 320 comprising a plurality of fiber Bragg gratings 322 (for reasons of clarity, only two fiber Bragg gratings are provided with reference numerals) is arranged on an outer surface of the inner housing 310. The fiber optic sensor 320 can, for example, be wound around the inner housing 110. This means that the fiber optic sensor 320 can be arranged by winding the fiber optic sensor 320 around the inner housing 310. The winding is indicated by the dotted line.

[0045] The piston ring 332 can press on the cylinder tube 310 from the inside. This can cause local expansion at the position of the piston ring 332 of the cylinder tube 310. The local expansion is indicated by the curved section of the cylinder tube 310. The local expansion of the cylinder tube 310 can exert a force on the fiber optic sensor 320. This force can be determined using the fiber Bragg gratings 322. This means that the fiber optic sensor 320 can generate sensor data indicative of an expansion of the cylinder tube 310 at a location on the piston ring 332. The sensor data can be received and processed by the device 350. This allows a current stationary stroke positioning of the piston 330 to be determined more accurately.

[0046] In Fig. 3 is further a part 320' spaced from the inner housing 310 (corresponding to the second fiber optic sensor from the description of Fig. 1) of the fiber optic sensor 320. The spaced portion 320' can be used to determine a system size independent of an extension of the inner housing 310. For example, the spaced portion 320' can be used to determine a temperature and / or a pressure or a temperature gradient and / or a pressure gradient along the inner housing 310. As shown in Fig. 3, the spaced portion 320' may be part of the fiber optic sensor 320. Alternatively (as described with reference to Fig. 1), the spaced portion 320' may be formed as a separate fiber optic sensor.

[0047] Fig. 4 shows a schematic representation of another embodiment of a vibration damper 402. The vibration damper 402 can be identical to the vibration damper from Fig. 3. The vibration damper 402 comprises a housing 400 with an inner housing 410 and a fiber optic sensor 420. The vibration damper 402 further comprises a device 450. The device 450 can be configured to receive and process sensor data from the fiber optic sensor 420. The vibration damper 402 further comprises a piston 430 comprising a piston ring 432. Fig. 4 shows a vibration damper in a non-stationary state.

[0048] In contrast to the representation from Fig. 3, the vibration damper 402 is in a transient state. For example, the vibration damper 402 can be excited at a base point 460 with a velocity ż. At the head point 470, the vibration damper 402 can be firmly clamped. Due to the excitation at the base point 460, an overpressure p Cpr in the lower pressure chamber 480.

[0049] The overpressure p Cprcan lead to a radial deformation or swelling (or expansion) of the inner housing 410 of the housing 400. This radial deformation is indicated by the lower curved area and the dashed lines. The radial deformation can be determined using the fiber optic sensor 420 or the fiber Bragg gratings 422. The device 450 can receive and evaluate the sensor data from the fiber optic sensor 420. As a result, the radial deformation can be determined based on the overpressure p Cpr determined and / or located on the inner housing 410.

[0050] Fig. 5 shows a schematic representation of an embodiment of a two-tube vibration damper 502 comprising a housing 500 according to the invention, for example a housing as described with reference to Fig. 1. The two-tube vibration damper 502 comprises a housing 500 comprising an inner housing 510, an outer housing 516, and a fiber optic sensor 520. The fiber optic sensor 520 comprises a plurality of fiber Bragg gratings 522 (for clarity, only two fiber Bragg gratings are provided with reference numerals). The fiber optic sensor 520 can be communicatively connected via an interface 548 to a device 550 for evaluating sensor data from the fiber optic sensor 520. The device can be formed separately or externally to the two-tube vibration damper 502.

[0051] The fiber optic sensor 520 can be wound and fixed at a defined pitch around the inner housing 510, i.e., the vibration damper inner tube. The winding is indicated by the dotted line. In particular, the pitch can be defined by a dimension of the fiber optic sensor 520 and the inner housing 510. For example, the fiber optic sensor 520 can be wound as tightly as possible around the inner housing 510. In this case, adjacent windings of the fiber optic sensor 520 can abut one another.

[0052] By using a suitable number of fiber Bragg gratings, in combination with a suitable positioning in the fiber optic sensor 520 (for example, so that they are arranged adjacent to one another along an axial extent of the inner housing 510 when wrapped around the inner housing 510), an improved determination of a parameter of the twin-tube vibration damper 502 can be achieved. Optionally, the pitch of the fiber optic sensor 520 can be adapted to the inner housing 510. By selecting a suitable number of fiber Bragg gratings and a suitable positioning of these in the fiber optic sensor 520 and optionally the pitch, a local radial strain of the inner housing 510, i.e., a cylinder tube strain, can be determined more effectively over the damper stroke.

[0053] To determine the temperature over the damper stroke, a portion of the fiber optic sensor 520 spaced apart from the inner housing 510 can be used. The fiber Bragg gratings of the spaced apart portion of the fiber optic sensor 520 can be decoupled from the inner housing, i.e., the cylinder tube, by the distance from the inner housing 510. The spaced apart portion of the fiber optic sensor 520 can enable temperature determination over the stroke, i.e., the determination of a temperature gradient. This allows temperature influences on the expansion of the inner housing 510 and thus on the fiber Bragg gratings arranged on the outer surface of the inner housing 510 to be determined and optionally compensated.

[0054] Optionally, a radial expansion of the outer housing 520 can also be detected. For this purpose, the fiber optic sensor 520 can be arranged on the outer housing 520. Alternatively, another fiber optic sensor can be arranged on the outer housing 520. By determining a radial expansion of the outer housing 520, a pressure in the compensation chamber (i.e., the at least partially enclosed space) can be determined. For example, the fiber optic sensor 520 can be mounted in a partial region, in particular in a region around the central layer.

[0055] By using the fiber optic sensor 502, information on damper system state variables and / or dependent parameters can be determined. This allows the damper system behavior to be determined. For example, stroke positioning, damper relative velocity, expansion-causing internal pressures, applied damper force, and conclusions about NVH properties can be drawn using corresponding vibration measurements on the damper or cylinder tube and / or condition monitoring.

[0056] Fig. 6 shows an embodiment of a vehicle 600. The vehicle 600 includes chassis 610. The chassis 610 includes a vibration damper 630, such as with reference to one of the Fig. 2-5 or a housing 620, such as with reference to Fig.1. Especially in the field of application of a vehicle 600, the housing 620 according to the invention has additional advantages: A parameter of the vibration damper can be determined more effectively during operation of the vehicle 600. Reference symbol 100a, 100b housing 110 inner housing 112 exterior area 120a, 100b (first) fiber optic sensor 122, 122b Fiber Bragg gratings 202 Vibration dampers 230 pistons 232 piston ring 300 housings 302 vibration dampers 310 inner housing 320 fiber optic sensors 320' spaced part of the fiber optic sensor 322 Fiber Bragg Gratings 330 pistons 332 piston ring 350 device 400 housings 402 Vibration damper 410 inner casing 420 fiber optic sensor 422 Fiber Bragg Gratings 430 pistons 432 piston ring 450 device 460 foot point 470 head point 480 lower pressure chamber 502 vibration damper 510 inner housing 516 Outer casing 520 fiber optic sensor 522 Fiber Bragg Gratings 548 interface 550 device 600 vehicles 610 chassis 620 housing 630 vibration dampers

Claims

[1] A housing (100) for a vibration damper for a vehicle, comprising: an inner housing (110), the inner housing (110) being configured to receive a piston; and a fiber optic sensor (120), wherein the fiber optic sensor (120) comprises a fiber Bragg grating (122), and wherein the fiber optic sensor (120) is arranged on an outer surface of the inner housing (110). [2] The housing (100) of claim 1, wherein the fiber optic sensor (120) comprises a plurality of fiber Bragg gratings, and wherein the fiber optic sensor (120) is arranged on the outer surface of the inner housing (110) such that the plurality of fiber Bragg gratings are spaced apart along an axial extent of the inner housing (110). [3] The housing (100) of claim 2, wherein the plurality of fiber Bragg gratings are spaced apart at a maximum distance of 1mm along the axial extent of the inner housing (110). [4] The housing (100) according to one of claims 2 or 3, wherein two fiber Bragg gratings of the plurality of fiber Bragg gratings are arranged radially opposite one another on the inner housing (110). [5] The housing (100) of any preceding claim, further comprising a second fiber optic sensor, wherein the second fiber optic sensor comprises a fiber Bragg grating, and wherein the second fiber optic sensor is spaced apart from the inner housing (110) along an axial extent of the inner housing (110). [6] The housing (100) of any preceding claim, further comprising an outer housing (516), wherein the outer housing (516) at least partially surrounds the fiber optic sensor (120). [7] The housing (100) of any preceding claim, further comprising a third fiber optic sensor, wherein the third fiber optic sensor comprises a fiber Bragg grating, and wherein the fiber Bragg grating is disposed on an outer surface of the inner housing (110). [8] A vibration damper (200) for a vehicle, comprising: a housing (100) for a vibration damper according to one of the preceding claims; and a piston (230), wherein the piston is arranged within the inner housing (110) of the housing (100). [9] The vibration damper (200) according to claim 8, further comprising a device (350; 450; 550) comprising an interface and a data processing circuit, the device (350; 450; 550) being configured to: to receive sensor data from a fiber optic sensor; and to determine at least one variable from the variables of stroke positioning, piston relative speed, expansion-causing internal pressures and set piston force. [10] A vehicle (600) comprising a housing (620) according to any one of claims 1-7 or a vibration damper (630) according to any one of claims 8 or 9.

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