AIR SPRING WITH A SENSOR ARRANGEMENT

Abstract

An air spring (100) for a vehicle is provided. The air spring comprises a first mounting element (110) for being fixed to a vehicle's chassis (210), a second mounting element (120) for being fixed to a movable part (220) of a vehicle being movable with respect to the chassis, a bellow (130) extending from the first mounting element to the second mounting element and including an air volume (140), and a sensor arrangement (150) being arranged within the air volume. The sensor arrangement is adapted for sensing at least one of a road condition, a vehicle condition and a pay load condition.

Claims

1.-20. (canceled)

21. An air spring system comprising: a first mounting element adapted for being fixed to a chassis of a vehicle; a second mounting element adapted for being fixed to a movable part of the vehicle, wherein said movable part is movable with respect to the chassis of the vehicle; a bellow extending from the first mounting element to the second mounting element, wherein the bellow includes an air volume; a sensor arrangement completely contained within the air volume, wherein the sensor arrangement comprises a plurality of sensors; a control unit adapted for receiving sensed signals from the sensor arrangement; and a wireless power supply adapted for wireless transfer of power to the sensor arrangement.

22. The air spring system of claim 21, wherein the sensor arrangement further comprises a transmitter for wirelessly transmitting sensed data to an external receiving unit.

23. The air spring system of claim 21, wherein the wireless power supply is adapted for wireless transfer of power from outside of the air volume to inside of the air volume.

24. The air spring system of claim 23, wherein the wireless power supply comprises an induction loop, wherein the induction loop is arranged at an outer surface of the bellow.

25. The air spring system of claim 21, wherein the wireless power supply is positioned within the air volume of the bellow.

26. The air spring system of claim 25, wherein the wireless power supply comprises an induction loop, wherein the induction loop is arranged at an inner surface of the bellow.

27. The air spring system of claim 21, wherein the control unit is further adapted to conduct a signal profile analysis based on the sensed signals and correlations thereof.

28. The air spring system of claim 21, wherein: the sensor arrangement includes a first accelerometer and a second accelerometer, the first accelerometer is fixedly mounted with respect to the first mounting element and the second accelerometer is fixedly mounted with respect to the second mounting element, and the first accelerometer and the second accelerometer are mounted to allow a differential mode measurement with respect to the first accelerometer and the second accelerometer.

29. The air spring system of claim 21, wherein: the sensor arrangement includes a first gyroscope and a second gyroscope, the first gyroscope is fixedly mounted with respect to the first mounting element and the second gyroscope is fixedly mounted with respect to the second mounting element, and the first gyroscope and the second gyroscope are mounted to allow a differential mode measurement with respect to the first gyroscope and the second gyroscope.

30. The air spring system of claim 21, wherein the plurality of sensors includes at least one temperature sensor and at least one microphone.

31. The air spring system of claim 21, wherein the control unit is further adapted for evaluating the sensed signals upon at least one of a road condition, a vehicle condition and a payload condition.

32. The air spring system of claim 21, wherein the control unit is further adapted for: accumulating the sensor signals from each sensor arrangement in each air spring on the vehicle; and providing a status of the vehicle based on the sensor signals from each of the sensor arrangements in each of the air springs on the vehicle.

33. The air spring system of claim 21, wherein the control unit is further adapted for comparing the sensed signals and correlations thereof with known signal profiles to identify and recognize a current signal profile.

34. An air spring system comprising: a first mounting element adapted for being fixed to a chassis of a vehicle; a second mounting element adapted for being fixed to a movable part of the vehicle, wherein said movable part is movable with respect to the chassis of the vehicle; a bellow extending from the first mounting element to the second mounting element, wherein the bellow includes an air volume; a sensor arrangement completely contained within the air volume, wherein the sensor arrangement comprises a plurality of sensors; a control unit adapted for receiving sensed signals from the sensor arrangement; and a wireless power supply adapted for wireless transfer of power to the sensor arrangement wherein the wireless power supply is positioned within the air volume of the bellow, wherein the wireless power supply comprises an induction loop, and wherein the induction loop is arranged at an inner surface of the bellow.

35. The air spring system of claim 34, wherein the plurality of sensors comprises at least two different types of sensors, wherein the at least two different types of sensors are selected from the group consisting of: a gyroscope, a microphone, a temperature sensor, an air pressure sensor, and an accelerometer.

36. The air spring system of claim 34, wherein the control unit is further adapted for: accumulating the sensor signals from each sensor arrangement in each air spring on the vehicle; and providing a status of the vehicle based on the sensor signals from each of the sensor arrangements in each of the air springs on the vehicle.

37. The air spring of claim 34, wherein the control unit is further adapted for comparing the sensed signals and correlations thereof with known signal profiles to identify and recognize a current signal profile.

38. The air spring system of claim 37, wherein the sensor arrangement includes a first sensor coupled to the first mounting element and a second sensor coupled to the second mounting element, wherein conducting the signal profile includes comparing a measurement from the first sensor with a measurement from the second sensor.

39. An air spring system comprising: a first mounting element adapted for being fixed to a chassis of a vehicle; a second mounting element adapted for being fixed to a movable part of the vehicle, wherein said movable part is movable with respect to the chassis of the vehicle; a bellow extending from the first mounting element to the second mounting element, wherein the bellow includes an air volume; a sensor arrangement completely contained within the air volume, wherein the sensor arrangement comprises a plurality of sensors; a control unit adapted for receiving sensed signals from the sensor arrangement; and a wireless power supply adapted for wireless transfer of power to the sensor arrangement wherein the wireless power supply is positioned outside of the air volume of the bellow, wherein the wireless power supply is adapted for wireless transfer of power from outside of the air volume to inside of the air volume, wherein the wireless power supply comprises an induction loop, and wherein the induction loop is arranged at an outer surface of the bellow.

40. An air spring system comprising: a first mounting element adapted for being fixed to a chassis of a vehicle; a second mounting element adapted for being fixed to a movable part of the vehicle, wherein said movable part is movable with respect to the chassis of the vehicle; a bellow extending from the first mounting element to the second mounting element, wherein the bellow includes an air volume; a sensor arrangement completely contained within the air volume, wherein the sensor arrangement comprises a plurality of sensors; a control unit adapted for receiving sensed signals from the sensor arrangement; and a means for wirelessly transferring power from a power source external to the air volume to the sensor arrangement internal to the air volume.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 illustrates an air spring according to an exemplary embodiment of the invention.

[0047] FIG. 2 illustrates a sensor arrangement for an air spring according to an exemplary embodiment of the invention.

[0048] FIG. 3 illustrates an air spring according to an exemplary embodiment of the invention.

[0049] FIG. 4 illustrates a wheel suspension with an air spring according to an exemplary embodiment of the invention.

[0050] FIG. 5 illustrates an air spring system according to an exemplary embodiment of the invention.

[0051] FIG. 6A illustrates an air spring according to an exemplary embodiment of the invention.

[0052] FIG. 6B illustrates an air spring according to an exemplary embodiment of the invention.

[0053] FIG. 6C illustrates an air spring according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0054] FIG. 1 illustrates an air spring 100 with a first mounting element 110, a second mounting element 120, and a bellow 130. The first mounting element in form of a top plate, the second mounting element in form of a bottom plate, and the bellow contain or include a volume and in particular the air volume 140.

[0055] In an operating mode of the air spring, the top plate and the bottom plate may move towards each other along the direction arrow 105 by movements of the bottom plate and/or by movements of the top plate.

[0056] Inside of the air spring, i.e. within the air volume 140, a sensor arrangement 150 is located such that a first sensor arrangement unit 150A is arranged at the first mounting element 110 and a second sensor arrangement unit 150B is arranged at the second mounting element 120. Both sensor arrangement units may be functionally linked to each other, i.e. electrically interconnected and/or share a common data transmission channel for transmitting and/or receiving signals, data, and information from and to each other, respectively.

[0057] The first sensor arrangement unit 150A is adapted for measuring vibrations, oscillations, and/or accelerations of the first mounting element, i.e. of the top plate, wherein the second sensor arrangement unit 150B is adapted for measuring vibrations, oscillations, and/or accelerations of the second mounting element, i.e. the bottom plate. As both sensor arrangement units 150A, 150B are located inside the air volume 140 of the air spring 100 and transmit the measured physical parameters wireless to a receiver (not shown in FIG. 1) located outside of the air volume, no wire-bound connection may be led from the air volume outside of the air spring. Thus, no additional openings for such wires may be required and the air volume is protected against intrusion of dust, water, and other dirt particles.

[0058] It should be noted, that the sensor arrangement may comprise a single sensor arrangement unit mounted to the first mounting element or the second mounting element as well as a multitude of sensor arrangement units, of which a plurality of sensor arrangement units may be mounted to each one of the first mounting element and the second mounting element.

[0059] Inside of the air volume 140, a wireless power supply 190 is arranged at the first mounting element for providing electrical energy to the sensor arrangement 150. The wireless power supply 190 may in particular be an energy receiver for receiving energy transmitted via microwaves or may base on the principle of induction, wherein the energy is generated by the movements of the power supply 190 and/or by the movements of the first mounting element.

[0060] Alternatively, the power supply may be mounted to the second mounting element as well as more than one power supply units may be used. Further, an induction loop may be arranged at an inner surface or at an outer surface of the bellow 130.

[0061] FIG. 2 illustrates a sensor arrangement 150, and in particular a sensor arrangement unit, comprising a sensor 155 with a first accelerometer 156A, a first gyroscope 157A, and a first microphone 158A, each adapted for measuring physical parameters as described above and hereinafter. The sensor arrangement further comprises a transmitter 151 for transmitting data, i.e. the signals corresponding to the measured physical parameters, to a receiver 270, which may in particular be located outside of the air volume 140 of the air spring 100. The signal transmission is carried out wireless, which is indicated by arrow 151A.

[0062] The sensor arrangement 150 may comprise any one of the sensor types named above and hereinafter additionally or optionally to the first accelerometer 156A, the first gyroscope 157A, and the first microphone 158A shown in FIG. 2.

[0063] FIG. 3 illustrates another exemplary embodiment of the air spring, wherein the first mounting element 110 comprises a mounting opening 160 for providing access to the air volume in case mounting steps and/or repairing steps have to be carried out. A sensor arrangement carrier 165 is provided for covering and uncovering the mounting opening 160, i.e. to close or open the air volume 140, respectively. In order to bring the sensor arrangement carrier 165 from an uncovering state to a covering state of the mounting opening 160, the sensor arrangement carrier is to be moved towards the arrow 169.

[0064] The sensor arrangement carrier 165 comprises a sensor mounting portion 166 and an outside portion 167, wherein the sensor mounting portion 166 comprises a surface of the sensor arrangement carrier 165 directed towards the air volume 140 in the covering state, and wherein the outside portion comprises a surface of the sensor arrangement carrier 165 directed opposite to the air volume in the covering state.

[0065] Further, the sensor arrangement carrier 165 comprises a seal line 168 which is adapted to seal the air volume against intrusion of particles from the surroundings of the air springs, i.e. to tightly close the air volume in the covering state of the sensor arrangement carrier. The seal line may in particular be a rubber lip and/or may comprise other plastically and/or elastically malleable materials.

[0066] A sensor arrangement 150 is mounted to the sensor mounting portion 166. Thus, when moving the sensor arrangement carrier 165 from the covering state to the uncovering state, a direct access to the sensor arrangement 150 for maintenance purposes is possible without the requirement to work inside the air volume. However, an access to the inside of the air volume is also possible through the mounting opening, in case a further sensor arrangement unit may be arranged at the second mounting portion.

[0067] FIG. 4 illustrates a wheel suspension 220 and a vehicle's chassis 210, which are mechanically linked to each other and have an air spring 100 for dampening vibrations of the wheel 225 due to uneven road condition, wherein one of the mounting elements of the air spring is mounted to the wheel suspension 220 and the other one of the mounting elements of the air spring is mounted to the vehicle's chassis 210.

[0068] The wheel suspension 220 may move along the arrow 222 when the road rolls over an uneven street and, as a result of the vibrations of the wheel 225 and of the wheel suspension 220, the mounting elements of the air spring are moving frequently towards and away from each other like indicated by arrow 105. The air spring and in particular the air volume within the air spring is adapted to dampen the vibrations of both the wheel suspension and the vehicle's chassis as to not transfer or transmit these vibrations from one of these parts to the other one, respectively.

[0069] The vibrations of the wheel suspension 220 are detected by the second accelerometer 156B which is mounted to the bottom plate of the air spring and the vibrations of the vehicle's chassis 210 are detected by the first accelerometer 156A which is mounted to the top plate of the air spring.

[0070] Accordingly, the detected signals of the physical parameter acceleration measured by the first and second accelerometers 156A, 156B are indicated by the signal patterns 159A and 159B. The signal pattern 159B belongs to the second accelerometer 156B which is mechanically attached via the bottom plate to the wheel suspension 220 and thus subjected to vibrations caused by an uneven road, for example. The signal pattern 159A belongs to the first accelerometer 156A which is mechanically attached via the top plate to the vehicle's chassis 210 and thus subjected to vibrations of the chassis which are damped or muffled by the air spring.

[0071] The signal pattern 159A is smoothed and damped with respect to the signal pattern 159B. In other words, the signal pattern 159B may be considered as an input signal which is to be damped by the air spring and the signal pattern 159A may be considered as an output signal transmitted to the vehicle's chassis and caused by the input signal 159B.

[0072] FIG. 5 illustrates an air spring system 300, comprising four air springs 100 which transmit the data measured by the sensor arrangement of each of the air springs to a control unit 310. The shown link between the air springs and the control unit 310 is a data link which may be either wire-bound or wireless. The data link may also be directed from the sensor arrangement of the air springs directly to the control unit, as well as first transmitted from the sensor arrangement to a receiving unit as shown in FIG. 2 which then transmits the data to the control unit.

[0073] The air spring system 300 may be mounted in a vehicle such that at least one air spring is assigned to one wheel or one wheel suspension. FIG. 5 illustrates this principle with a four-wheeled vehicle. It should be understood that the air spring system as described above and hereinafter may comprise more or less than four air springs and may also be used in vehicles comprising more or less than four wheels or wheel suspensions.

[0074] FIGS. 6A, 6B, and 6C illustrate the possible locations of a sensor arrangement, wherein both the first and second mounting elements 110, 120 are ring-shaped plates within the air volume of the air spring.

[0075] According to FIG. 6A, a first sensor arrangement unit 150A, for example in form of an accelerometer, is located on the first mounting element 110 which is a ring-shaped top plate within the air spring. The first mounting element may be adapted for being attached close to a vehicle's chassis such that a location of the first sensor arrangement unit close to the chassis may enable measurement of a resonance frequency of the vehicle's chassis and measurements due to leveling settings of the vehicle.

[0076] According to FIG. 6B, a second sensor arrangement unit 150B, for example in form of an accelerometer, is located on the second mounting element 120. The second mounting element may be adapted for being attached to a wheel suspension such that the location of the second sensor arrangement unit close to the wheel suspension may enable road surface analysis and system diagnosis.

[0077] According to FIG. 6C, a first sensor arrangement unit 150A and a second sensor arrangement unit 150B, for example each in form of an accelerometer, are located on the first mounting element and the second mounting element, respectively. When operated separate from each other, i.e. each sensor arrangement unit individually, the sensor arrangement units may be operated as described in connection with FIGS. 6A, 6B. Furthermore, when comparing the measured signals from the sensor arrangement units, a differential mode measurement may be enabled.

[0078] In particular, the first sensor arrangement unit 150A and the second sensor arrangement unit 150B may be arranged such that the move directly towards each other in case the bottom plate moves towards the top plate, i.e. the sensor arrangement units 150A, 150B have a common moving axis parallel to the moving direction of the top plate and the bottom plate in an operating state of the air spring. In other words, in one exemplary embodiment the first and the second sensor arrangement unit may not have any lateral displacement or misalignment, i.e. the first sensor arrangement and the second sensor arrangement are with respect to the moving direction of the top and bottom plate above/below each other.

[0079] The sensor arrangement may be placed either at a top of the air spring or at the bottom. When differential signal measurements are required or signal comparisons then the sensor arrangement may be placed at both the top and the bottom (like when calculating the damping factor or when trying to reduce vehicle vibrations caused by the combinations of the effects from the road surface, vehicle speed, and tire pressure, for example).

[0080] The wheel of a vehicle is mechanically connected to the bottom part of an air spring. The frame-work of the vehicle's chassis is resting at the top of the air spring unit. In this specific example two accelerometer sensor units are mounted in the top (Ay) and bottom part (By) of the Air-Spring unit mechanics. When the vehicle is rolling over a road covered with gravel, then a certain type of vibration-noise signal will be generated by the Accelerometer By. The vibration type of signal is mainly caused by the uneven road (road is not smooth). The accelerometer sensor Ay that is mounted near to the vehicle's chassis structure (in the top part of the air spring) will be muffled and dampened in comparison to the signal from By. Of course, in a standard suspension system a shock absorber is used as well, but is not discussed here any further. Driving over a smooth road surface will result in a far less noisy signal. Each of the two signals can be analyzed on its own (By, and Ay), or they can be compared to each other (building the differential-signal) depending on the objective of the signal analysis.

[0081] The information required to make definite and reliable statements about the measured physical parameters may be measured either directly (like the absolute axle tilting of the vehicle), indirectly through data-comparison (like the bending of the trailer main platform: differential signal by comparing the values of at least two gyroscopes placed at two different locations on the vehicle), or by advances signal analysis (like when determine the tire air pressure or the axle bearing performance: signal profile and signal frequency spectrum).

[0082] The air spring as described above and hereinafter may integrate a specific sensor array, i.e. sensor arrangement, onto already existing electronics of an air spring solution and may use an on-board computer for the processing of the signals from this sensor array.

[0083] The sensor arrangement may be placed at the most ideal location for the intended measurement: where the forces coming from the wheels and the axles act onto the main-system-frame (chassis, for example). The fast amount of additional measurement information will then be made available through one-and-the-same electrical connector that an air spring unit may already have or which is to be provided. The sensor arrangement may not require an additional housing and protection from the environment as it is placed onto an electronics board within the air volume of the air spring.

[0084] Depending on the physical parameters that have to be detected and measured and depending on the targeted signal quality, a number of different sensor types may be installed into the structure of the air spring. The minimum of recommended sensors to install may be 2 (accelerometers) at the top and bottom of the Air-Spring unit, respectively, and the advisable maximum number of sensors may be 12.

[0085] The possible combination of the sensor arrangement that may be installed in one air spring may be relatively high (>40). Some types of sensors may be categorized as optional, like a temperature sensor, an air pressure sensor, and a microphone. For an overview of the exemplary sensors, Table 1 is provided. These sensors may be placed elsewhere in a vehicle and may not have to be placed in or near the air spring. However, in case the air spring has already an electronic data acquisition system and a digital-serial bus interface included, it may be reasonable to add these optional sensors.

[0086] In most simple terms, the sensor arrangement or sensor arrays as described above and hereinafter, may be placed and mounted inside of the mechanics of the air spring, and can be placed and mounted from the outside of the air spring. The sensor arrangement has to be firmly attached to the mechanical structure of the air spring (the bottom piston or/and the top plate, also called the upper bit). The term firmly attached means that a good mechanical signal transfer has to be achieved as otherwise the electrical output signal from the sensor will be distorted, damped, and of poor quality. When mounting the sensors inside the air spring, i.e. within the air volume, the sensor arrangement cannot be seen from the outside, may be better protected from the environments (water, dust, and stones, others . . . ). In reverse, when mounting the sensor arrangement from the outside of the air volume, then they can be retro fitted, can be more easily maintained, repaired and serviced.

[0087] A signal processing stage for improving the signal quality may include the following features: automatic compensation of unwanted effects caused by changes of the environmental operating conditions, like temperature and supply voltage; signal filtering stages to improve the signal-to-noise ratio which may be built using discrete passive and/or active components, using advanced analogue filter ICs, programmable digital filter IC, or software operated digital filter systems (using a microprocessor, for example); customisation of the signal output format (analogue, serial digital, . . . ), wherein typical serial-digital signal interfaces may be formats like RS232, RS485, CAN, Lin Bus, Basic CAN; advanced methods to reduce or even to eliminate the unwanted effects of electro-magnetic interferences (often called: EMI), which may include also certain types of differential mode signal processing, frequency hopping, and plausibility signal analysis; signal frequency spectrum analyser functions when aiming to provide a signal-profile analysis (for diagnostic purposes, for example). Most likely, an advanced signal processing function may require the use of a micro-controller (for example in the form of a single chip RISC processor, or a low cost DSP).

TABLE-US-00001 TABLE 1 Measurement Number of Orientation and Importance/ sensors that Sensor Device Purpose Explanations Priority could be used Accelerometer X axis Measuring in driving Accelerating and 3 1 direction (horizontal) decelerating forces Accelerometer Y axis Measuring in vertical Vibrations caused by 1 2-differential direction road surface, Tire mode Pressure, Diagnostics, Resonances Accelerometer Z axis Measuring in left-right Centrifugal forces/ 2 1 direction (horizontal) curves Gyro X Axis Measuring in driving Allows vector 3 1 direction (horizontal) calculations Gyro Y Axis Measuring in vertical Vehicle leveling/tilting 2 2-differential direction in two axis/structural mode warping Gyro Z Axis Measuring in left-right Allows vector 3 1 direction (horizontal) calculations Microphone Measuring body Road Surface, Structural Optional/Cost 1 noise/vibration Diagnostics, Tire reduction pressure Temperature Air Temperature Assists in calculating Air Optional 1 (outside) Pressure, Diagnostics Temperature (inside) Compressed Air Assists in calculating Air Optional 1 Temperature Pressure, Diagnostics Pressure Compressed Air Optional 1 Pressure Advisable Max number of sensors per Air-Spring 1

LIST OF REFERENCE NUMERALS USED IN THE DRAWINGS

[0088] 100 air spring [0089] 105 suspension direction [0090] 110 first mounting element [0091] 120 second mounting element [0092] 130 bellow [0093] 140 air volume [0094] 150 sensor arrangement [0095] 150A first sensor arrangement unit [0096] 150B second sensor arrangement unit [0097] 151 transmitter [0098] 151A wireless transmission path [0099] 155 sensor [0100] 156A first accelerometer [0101] 156B second accelerometer [0102] 157A first gyroscope [0103] 157B second gyroscope [0104] 158A first microphone [0105] 158B second microphone [0106] 159A first signal pattern [0107] 159B second signal pattern [0108] 160 mounting opening [0109] 165 sensor arrangement carrier [0110] 166 sensor mounting portion [0111] 167 outside portion [0112] 168 seal line [0113] 169 mounting direction [0114] 190 wireless power supply [0115] 210 vehicle's chassis [0116] 220 movable part of the vehicle's chassis, wheel suspension [0117] 222 moving direction [0118] 225 wheel [0119] 300 air spring system [0120] 310 control system

[0121] This application claims benefit of European Patent Application Serial No. EP 12190374, filed on Oct. 29, 2012. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention.