• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    The method relates to a cylinder (100; 200; 400; 500), in particular for use in a hydraulic system, with a cylinder housing (102) with a cylindrical side wall (103); a piston (101) arranged axially slidably in the cylinder housing (102); at least one signal input device (106; 201; 401), which is arranged and shaped on the cylinder housing (103), to transmit an ultrasonic signal (108) such that the ultrasonic signal (108) extends along an inner side ( 103a) of the side wall (103) of the cylinder housing (102) displaced; at least one receiving device (107; 201; 401) which is arranged and shaped on the cylinder housing (102) to receive the ultrasonic signal (108) reflected from the piston (101); and an evaluation device (112) formed on the basis of a travel time (at) of the ultrasonic signal (108) between an outputting of the ultrasonic signal (108) by the signal input device (106; 201; 401 ) and receiving the ultrasonic signal (108) by the receiving device (107; 201; 401) determining a position (x) of the piston (101).
    公开号:NL2017634A
    申请号:NL2017634
    申请日:2016-10-18
    公开日:2017-05-10
    发明作者:Chabaud Antoine；Hahn-Jose Thomas
    申请人:Bosch Gmbh Robert；
    IPC主号:
    专利说明:

    Title: Cylinder and method for determining a position of a piston in a cylinder
    The present invention relates to a cylinder, in particular for use in a hydraulic system, and a method for determining a position of a piston in a cylinder, in particular for use in a hydraulic system.
    State of the art
    Various measuring methods are known for measuring a position of a piston in a cylinder, in particular a hydraulic cylinder. Method based on transit time measurements of ultrasonic signals is characterized by a high robustness and does not require bore of the piston. For example, a measuring method is known from the US6 119579A, wherein ultrasonic sensors are arranged on the outside of the cylinder and the position of the piston is determined on the basis of the duration of the ultrasonic measuring signal.
    These methods, however, depend on the wave spreading medium, in the case of hydraulic cylinders a hydraulic oil, since the sound velocity depends on the pressure and the temperature of the hydraulic oil as well as the type of oil. In particular, contamination of the wave-spreading medium, for example by metal particles or air bubbles, lead to further inaccuracies and potential measurement errors due to cavitation appearances.
    Revelation of the invention
    The present invention relates to a cylinder, in particular for use in a hydraulic system, characterized in that patent claim 1 and a method for determining a position of a piston in a cylinder, in particular for use in a hydraulic system system with the feature of the patent claim 6.
    According to a first aspect, the present invention thus provides a cylinder, in particular for use in a hydraulic system, with a cylinder housing with a cylindrical side wall, a piston arranged axially displaceable in the cylinder housing, at least one signal input device which is connected to the cylinder housing, i.e. arranged and formed on the side wall or an outer wall in the axial direction of the cylinder housing, to transmit an ultrasonic signal such that the ultrasonic signal moves along an inner side of the side wall of the cylinder housing, at least a receiving device which is arranged and shaped on the cylinder housing to receive the ultrasonic signal reflected from the piston, and an evaluation device which is formed on the basis of a travel time of the ultrasonic signal between an outputting of the ultrasonic signal by the signal input device and a reception of the ultrasonic signal by the receiver device a determine the position of the piston. In particular, the ultrasonic signal allows the ultrasonic signal to be reflected from a seal of the piston.
    The present invention thus provides, according to a second aspect, a method for determining a position of a piston in a cylinder, in particular for use in a hydraulic system. The method comprises outputting an ultrasonic signal on a cylinder housing with a cylindrical side wall, such that the ultrasonic signal moves along an inner side of the side wall of the cylinder housing. The method further comprises receiving the ultrasonic signal reflected from the piston arranged axially displaceable in the cylinder housing, and calculating a position of the piston on the basis of a travel time of the ultrasonic signal between sending and receiving the ultrasonic signal .
    Further preferred embodiments are part of the subclaims.
    Advantages of the invention
    It will be understood that the invention is versatile. For example, the term "cylinder" includes in particular pneumatic cylinder, hydraulic cylinder or hub cylinder, as they are used in many machines. The cylinder may be filled with a desired liquid, in particular with desired liquids or gases. The invention is also not limited to a specific shape of the cylinder, furthermore the piston slidably arranged in the cylinder housing can in particular also comprise a membrane.
    The diffusion medium of the ultrasonic signal is the inside of the side wall of the cylinder housing. A wave spreading speed of the ultrasonic signal can thus be well calculated, since the properties of the cylinder wall are known. The sound speed resp. the group speed of the ultrasonic signal in the cylinder wall of the cylinder according to the invention depends only on the wave mode and on the sound frequency in the cylinder wall. The properties of the cylinder wall, however, remain largely unchanged during the combined operating time of the cylinder and the dependencies of the ultrasonic spread can thus be calculated in a deterministic and reproducible manner. This dependence can easily be calibrated with a sensor installation and remains constant over the life of the cylinder. The cylinder according to the invention is thus distinguished from cylinders with ultrasonic sensors, wherein the ultrasonic signal moves in the hydraulic oil. In particular, a high measurement accuracy is possible.
    The determination of the piston position is therefore extremely robust in relation to the operating conditions of the hydraulic oil. Furthermore, an extensibility of the signal input device, receiving device and evaluation device for existing cylinders is easily possible.
    According to a further embodiment, the cylinder comprises an attachment piece, which is arranged on the side wall of the cylinder housing, and a transmitter arranged on the attachment piece. Here, the transmitter is formed to transmit the ultrasonic signal through the attachment so that an ultrasonic wave carrying the ultrasonic signal hits the cylinder housing at an angle of incidence. Furthermore, the angle of incidence is chosen such that the ultrasonic signal is broken at an interface of the attachment and cylinder housing such that the ultrasonic signal moves along an inner side of the side wall of the cylinder housing. The refraction of the ultrasonic signal is known in accordance with Snellius' refraction law, so that a suitable choice of the attachment with known refractive index of the attachment can be ensured by adjusting the angle of incidence that the ultrasonic signal is parallel to the inside of the side wall of the cylinder housing.
    According to a further embodiment, the signal input device is arranged on the side wall of the cylinder housing and comprises at least two electrodes, which are arranged and shaped to transmit an ultrasonic signal. Due to the electrical input of the ultrasonic signal by means of electrodes, the signal input device can be kept very small, so that a small space consumption is created.
    According to a further embodiment, the signal input device is arranged on an outer wall in the axial direction of the cylinder housing and comprises at least one sliding plate which is slidable in a direction parallel to the outer wall of the cylinder housing and is coupled to the cylinder housing by friction, Periodic displacement of the sliding plate on the outer wall of the cylinder housing an ultrasonic signal can be transmitted to the cylinder housing which moves along an inner side of the side wall of the cylinder housing. The term "sliding plate" is to be understood here to mean a plate or a plate, in particular a flat metal plate, which contacts a counterpart, which in particular can also be flat and metallic, and which contacts flat and parallel to the contact surfaces along this counterpart moves back and forth.
    A cylinder according to this further embodiment is distinguished by the fact that the signal transmission takes place on a bottom side and not on a side wall of the cylinder, which can be advantageous with certain requirements on the cylinder, since there is no space consumption on the side wall.
    According to a further embodiment, the signal input devices resp. the receiving devices are spaced apart in the axial direction. The cylinder comprises a control device which is formed for outputting an ultrasonic signal by the signal input devices and receiving the reflected ultrasonic signal by the receiving devices in a multiplexing method, in particular a time-multiplexing method or a frequency multiplexing method. The invention is hereby scalable and suitable for cylinder desired size, since the piston position can be fixed to different positions of the receiving devices. The piston position can therefore be precisely determined even with long cylinders.
    According to a further embodiment of the method, the control device is designed to control the signal input devices such that the signal input devices send time-shifted ultrasonic signals, a time difference between the sending of two ultrasonic signals by different signal input devices being larger is then the runtime of the ultrasonic signals.
    According to a further embodiment of the method, the sending of the ultrasonic signal takes place through an attachment which is arranged on the side wall of the cylinder housing. The ultrasonic signal hereby hits the cylinder housing at an angle of incidence and the angle of incidence is chosen such that the ultrasonic signal at the interface of the attachment and cylinder housing is broken such that the ultrasonic signal moves along an inner side of the side wall of the cylinder housing.
    According to a further embodiment of the method, the ultrasonic signal is output by means of at least two electrodes, which are arranged comb-like on the side wall of the cylinder housing.
    According to a further embodiment of the method, the sending of the ultrasonic signal is effected by shifting a sliding plate on an outer wall in a radial direction, the sliding plate being coupled to the outer wall by friction.
    According to a further embodiment of the method, the sending of the ultrasonic signal resp. receiving the reflected ultrasonic signal at different positions of the cylinder housing in a multiplexing method, in particular a time-multiplexing method or a frequency-multiplexing method. By applying different signal input devices, a precision of the measurement of the position of the piston can be increased. For example, each of the signal input devices may be responsible for a particular section of the cylinder. As a result, a reduction in precision on the basis of a limited range of the measuring range by sound damping along the distribution path of the ultrasonic signal can be prevented. Cross-influences between different signal input devices can be prevented by multiplexing strategies. Sound wave frequency ranges for the ultrasonic signals can also be used advantageously by the various signal input devices.
    According to a further embodiment of the method, the ultrasonic signals are transmitted time-shifted at the different positions of the cylinder housing, wherein a time difference between the sending of two ultrasonic signals at different positions of the cylinder housing is greater than the travel time of the ultrasonic signals . Since the sound speed, that is to say the spread speed of the ultrasonic signals, is substantially higher than the piston speed, a time-multiplexing method has no influence on the precision of the measuring system.
    Brief description of the drawings
    It is shown:
    FIG. 1 a cylinder according to a first embodiment of the present invention;
    FIG. 2 a cylinder according to a second embodiment of the present invention;
    FIG. 3 is a top view of an electrode structure of a signal input device according to the second embodiment of the present invention;
    FIG. 4 a cylinder according to a third embodiment of the present invention;
    FIG. 5 a cylinder according to a fourth embodiment of the present invention; and
    FIG. 6 is a flow chart for a method for determining a position of a piston in a cylinder.
    In all figures, the same resp. functionally identical elements and devices - unless otherwise specified - provided with the same designations.
    Description of the exemplary embodiments
    Figure 1 shows a cylinder 100, in particular a hydraulic cylinder for use in a hydraulic system. The cylinder 100 comprises a cylinder housing 102 with a cylindrical side wall 103, which is formed axially about an axis of symmetry of the cylinder 100, and a first outer wall 104 in the axial direction of the cylinder housing 102, which defines the cylinder 100 in the axial direction. Opposite the first outer wall 104, an opening 105 is formed in a second outer wall 115 of the cylinder housing 102, into which a piston 101 is axially slidably inserted. A position of the piston 101 is determined by a distance x from the first outer wall 104. The cylindrical side wall 103 of the cylinder housing 102 comprises an inner side 103a and an outer side 103b lying in the radial direction. The piston 101 herein comprises a seal 101a, which forms a radial outer range of the piston 101, contacts the outer side 103b of the cylinder housing and serves to seal a pressure space 116 between the piston 101 and the first outer wall 104 of the cylinder housing 102.
    A signal input device 106 is arranged on the cylindrical side wall 103. The signal input device 106 comprises an attachment piece 106a, which is arranged on the outside 103b of the cylindrical side wall 103 of the cylinder housing 102. The attachment piece 106a here advantageously consists of metal with a first refractive index n1, the first refractive index n1 differing from a second refractive index n2 of the cylinder housing 102.
    However, the invention is not limited thereto. The extension piece 106a can thus also be inserted into the cylindrical side wall 103.
    A transmitter 106b is arranged on the attachment 106a, which transmitter is formed to transmit an ultrasonic signal 108 through the attachment. The ultrasonic signal 108 is typically modulated on an ultrasonic wave. The ultrasonic signal can in particular also be a wave packet.
    The attachment 106 is wedge-shaped so that the ultrasonic signal 108 formed from the transmitter 106b hits the cylindrical side wall 103 at an angle of incidence φΐ with respect to a normal surface 109. At the interface 110 between the attachment 106a and the cylindrical side wall 103, the ultrasonic signal 108, resp. the ultrasonic wave carrying the ultrasonic signal 108 is broken. The refraction angle is determined from Snellius' refraction law, ie according to the following formula:
    Here, φ2 is the exit angle of the ultrasonic signal 108 in cylinder housing 102. With known refractive indexes nl and n2 of the attachment and of the cylinder housing 102, the incident angle φΐ is set such that the exit angle φ_2 is practically 90 °, so that the ultrasonic signal moves along the inside 103a of the side wall 103 of the cylinder housing 102. The ultrasonic signal 108 thus runs parallel to the cylindrical side wall 103. An ultrasonic wave carrying the ultrasonic signal 108, which is located on the inner side 103a of the side wall 103 and 32, respectively. displaced within half of the side wall 103 of the cylinder housing 102 is referred to as Rayleigh or Scholte wave.
    The ultrasonic signal 108 resp. the ultrasonic wave carrying the ultrasonic signal 108 is applied to a signal input device 106 for which position 114 the seal 10aa of the piston 101 is reflected and then propagates in counter-direction. The reflected ultrasonic signal 108 is received from a receiver device 107. The receiving device 107 is advantageously formed here as well as the signal input device 106, i.e. the receiving device 107 also comprises an attachment piece 107a and a receiver 107b arranged thereon.
    The receiving device 107 and the signal input device 106 are connected to a control device 111. The control device 111 controls the signal input device 106. The control device 111 comprises an evaluation device 112 which is formed on the basis of a travel time At of the ultrasonic signal 108 between an outputting of the ultrasonic signal 108 by the signal input device 106 and receiving the reflected ultrasonic signal 108 by determining the receiving device 107 from the position of the piston 101, i.e. the distance x between first outer wall 104 and piston 101. To this end, the evaluation device 112 measures a first time point t1 of the outputting of the ultrasonic signal 108 by the signal input device 106 and a second time point t2 of the receiving of the reflected ultrasonic signal 108 by the receiving device 107. The transit time At of the ultrasonic signal 108 is therefore given by At = t2 -t1. The evaluation device 112 uses a known distance x2 from the signal input device 106 and a known distance x1 from the receiving device 107 of the first outer wall 104 of the cylinder housing 102 when determining a position of the piston 101. A total travel distance Ax of the ultrasonic signal 108 between sending and receiving is calculated according to the following formula:
    wherein v is the spreading speed of the ultrasonic signal 108 in the material of the cylindrical side wall 103. The total travel distance Δy of the ultrasonic signal 108 is equal to 2 γ + x 2 - x 1, where γ 1 is the distance of the signal input device 106 from the piston 101, and wherein distances d 1 and d2 of the transmitters 106b resp. of the receivers 107b of the cylindrical side wall 103, each time measured at the angle of incidence φΐ, are neglected, since they are small with respect to the distance γ1 of the signal input device 106 of the piston 101 and a distance x2 -x1 of the signal input device 106 and receiving device 107.
    The distance x of the piston of the first outer wall 104 thus becomes:
    The evaluation device 112 is formed on the basis of this formula to measure the distance x of the piston from the first outer wall 104.
    For example, the spreading speed of the ultrasonic signal 108 in the material of the cylindrical side wall 103 is 1500 m / s and the distance x2 of the signal input device 106 from the first outer wall 104 of the cylinder housing 102 is 10 cm and the distance x1 of the receiving device 107 from the first outer wall 104 of the cylinder housing 102 equal to 12 cm, and the travel time Δt of the ultrasonic signal 108 equals 1 ms, so is obtained for the distance x from the piston of the first outer wall 104:
    The evaluation device 112 may further be arranged to check a reflection of the ultrasonic signal 108 on the second outer wall 115, this reflection resulting from a part of the ultrasonic signal, which is not already from the front point 114 of the seal 101a of the piston 101 was reflected. Furthermore, the evaluation device 112 may be formed around the distances d1 and d2 of the transmitters 106b resp. From the receivers 107b of the cylindrical side wall 103.
    Further, the evaluation device 112 is configured to monitor a sound energy radiation from the ultrasonic signal 108 in a hydraulic oil inside of the cylinder. In particular, an intensity of the ultrasonic signal 108 is selected such that an adequate signal-to-noise ratio is guaranteed at the signal reading.
    The invention is not limited thereto. Thus, the evaluation device 112 may also be the same as the signal input device 106.
    Figure 2 shows a cylinder 200 according to a second embodiment of the present invention. Here, the signal input device 201 is the same as the receiving device 201 and consists of electrodes 201a. The electrodes 201a comprise a first electrode 201a-1 and a second electrode 201a-2, which are comb-shaped, the first electrode 201a-1 being toothed with the second electrode 201a-2, as illustrated in Figure 3. By applying a current, an ultrasonic signal can be transmitted directly to the side wall 103 of the cylinder housing 102, the ultrasonic signal moving in an axial direction along the inner side 103a of the side wall 103 or inner half of the side wall 103, respectively. . The signal input device 201 also serves as the ultrasonic signal receiving device 201. The evaluation device 112, which is connected with the signal input device resp. The receiver device 201 is connected, again formed to determine a position of the piston 101 on the basis of the transit time α of the ultrasonic signal. The evaluation device 112 considers a known distance x3 from the receiving device resp. signal input device 201 from the first outer wall 104 of the cylinder. The evaluation device 112 is configured to calculate the distance x of the piston 101 from the first outer wall 104 according to the following formula:
    A distance d from the teeth of the comb-shaped electrodes 201a-1 and 201a-2 here corresponds to a wavelength λ of the ultrasonic signal, wherein the wavelength λ is advantageously between 2 and 7 mm and advantageously equal to 5 mm is.
    The invention is not limited thereto. The receiving device can thus also be distinguished from the signal input device 201. In particular, a receiving device, which is constructed in the same way as the signal input device 201, can be arranged alongside the signal input device 201 on the cylindrical side wall 103.
    Figure 4 shows a cylinder 400 according to a third embodiment of the present invention, in this case a signal input device 401 is arranged on the first outer wall 104. The signal input device 401 herein advantageously comprises a metal shelter plate 403, which is slidable in a radial direction 404, i.e. in a direction 404 parallel to the first outer wall 104 of the cylinder housing 102. The sliding plate 403 is herein mechanically coupled to the cylinder housing 102, i.e. by friction. By periodically shifting the sliding plate 403 in the direction 404 parallel to the first outer wall 104 of the cylinder housing, the signal input device 401 is formed to transmit an ultrasonic signal to the cylinder housing 102. The ultrasonic signal 108 travels along the inside 103a of the side wall 103.
    The signal input device 401 simultaneously serves as a receiving device, which receives the ultrasonic signal 108 reflected from the seal 10a of the piston 101. The evaluation device 112 of the control device 111 coupled to the signal input device 401 is formed here, a position of the piston 101, that is to say a distance x from the piston 101 of the first outer wall 104 on the basis of the running time Δt of the ultrasonic signal 108 can be calculated according to the following formula:
    However, the receiving device can also be separate from the signal input device 401 and be arranged, for example, next to the signal input device 401 on the first outer wall 104.
    Figure 5 shows a cylinder 500 according to a fourth embodiment of the present invention. According to this embodiment, four ultrasonic devices 502a to 502d are arranged in distances xa to xd of the second first outer wall 115 in the axial distance at the cylindrical side wall 103 of the cylinder housing 102. The ultrasonic devices 502a to 502d here in each case comprise a signal input device and a receiving device according to one of the embodiments described above. The ultrasonic devices 502a to 502d are each coupled to the control device 111. The control device 111 furthermore comprises a multiplexing device 501, which controls the ultrasonic devices 502a to 502d. The multiplexing device 501 is particularly adapted to control the ultrasonic devices 502a to 502d in a time-multiplexing method or in a frequency-multiplexing method. That is, for example, the signal input devices each time-shifted ultrasonic devices 502a to 502d, in particular predetermined time distances, emit an ultrasonic signal 108. The time difference between the sending of the ultrasonic signals by the different ultrasonic devices 502a to 502d is advantageously longer here than the travel time of the ultrasonic signal 108 between the sending and the receiving. According to the frequency multiplexing method, the ultrasonic signals can also be transmitted simultaneously to the ultrasonic devices 502a to 502d, the frequency ranges of the transmitted ultrasonic signals being different.
    On the basis of the received transit times, the evaluation device 112 can again determine a position of the piston 101, i.e. a distance x of the piston from the first outer wall 104 of. When different distances x from the piston 101 are determined from the running times of the different ultrasonic devices 502a to 502d, an average value can be determined, for example. However, it is also advantageous to choose from each measurement result, which results from each ultrasonic device closest to the piston 101 on the basis of the measurements, and the position of the piston on the basis of these measurement results. 101 are determined.
    Figure 6 shows a flow chart for explaining a method for determining a position of a piston 101 in a cylinder. The method comprises a first step S1 of outputting an ultrasonic signal 108 on a cylinder housing 102 with a cylindrical side wall 103. The ultrasonic signal is transmitted such that it is located along an inner side 103a of the side wall 103 of the cylinder housing 102 that is, displaced in an axial direction. The outputting can here in particular be carried out by a signal input device described in the other embodiments.
    The method further comprises a second step S2 of receiving the ultrasonic signal 108 reflected from a seal 101a of a piston 101 located inside of the cylinder housing 102. The receiving devices described above are advantageously used herein.
    Finally, the method comprises a third step of calculating a position of the piston 101, i.e. of a distance x of the piston 101 from a first outer wall 104 of the cylinder 103. The calculating position is hereby determined on the basis of a running time Calculates Δt of the ultrasonic signal 108 between the sending and receiving of the ultrasonic signal.
    权利要求:
    Claims (12)
    [1]
    A cylinder (100; 200; 400; 500), in particular for use in a hydraulic system, with a cylinder housing (102) with a cylindrical side wall (103); a piston (101) arranged axially slidably in the cylinder housing (102); at least one signal input device (106; 201; 401), which is arranged and shaped on the cylinder housing (103) to transmit an ultrasonic signal (108) such that the ultrasonic signal (108) extends along an inner side (103a) of the side wall (103) of the cylinder housing (102) displaced; at least one receiving device (107; 201; 401), which is arranged and shaped on the cylinder housing (102) to receive the ultrasonic signal (108) reflected from the piston (101); and an evaluation device (112) which is formed to, on the basis of a travel time (At) of the ultrasonic signal (108) between an outputting of the ultrasonic signal (108) by the signal input device (106; 201; 401) and receiving the ultrasonic signal (108) by determining the receiving device (107; 201; 401), a position (x) of the piston (101).
    [2]
    The cylinder (100; 200; 400; 500) according to claim 1, wherein the signal input device (106; 201; 401) comprises: an attachment (106a) arranged on the side wall (103) of the cylinder housing (102) and a transmitter (106b) arranged on the attachment (106a), the transmitter (106b) being formed to transmit the ultrasonic signal (108) through the attachment such that the ultrasonic signal (108) is an angle of incidence (φΐ) hits the cylinder housing (102), the angle of incidence (φΐ) being selected such that an ultrasonic wave carrying the ultrasonic signal (108) meets an interface (110) of attachment (106a) and cylinder housing (102) is broken such that the ultrasonic signal (108) travels along an inner side (103a) of the side wall (103) of the cylinder housing (102).
    [3]
    The cylinder (100; 200; 400; 500) according to claim 1, wherein the signal input device (106; 201; 401) is arranged on the side wall (103) of the cylinder housing (102) and at least two electrodes (201a) 1, 201a-2), which are arranged and shaped in a comb-like manner to emit an ultrasonic signal (108).
    [4]
    The cylinder (100; 200; 400; 500) according to claim 1, wherein the signal input device (106; 201; 401) is arranged on an outer wall (104) in the axial direction of the cylinder housing (102) and at least one sliding plate (403) which is slidable in a direction (404) parallel to the outer wall (104) of the cylinder housing (102) and is frictionally coupled to the cylinder housing (102), with periodic sliding of the sliding plate (403) the outer wall (104) of the cylinder housing (102) is capable of transmitting an ultrasonic signal (108) to the cylinder housing (102), which moves along an inner side (103a) of the side wall (103) of the cylinder housing (102).
    [5]
    Cylinder (500) according to any one of claims 1 to 4, wherein the signal input devices (502a to 502d) resp. the receiving devices (502a to 502d) are each arranged remotely in axial direction, and wherein the cylinder (500) comprises a control device (111), which is formed to send an ultrasonic signal (108) through the signal input devices (502a to 502d) and a receiving of the reflected ultrasonic signal (108) by the receiving devices (502a to 502d) in a multiplexing method, in particular a time-multiplexing method or a frequency -multiplexing method.
    [6]
    The cylinder (500) according to claim 5, wherein the control device (111) is adapted to control the signal input devices (502a to 502d) such that the signal input devices (502a to 502d) are time-shifted output ultrasonic signals (105), wherein a time difference between the output of two ultrasonic signals (108) by different signal input devices (502a to 502d) is greater than the travel time (At) of the ultrasonic signals (108) .
    [7]
    A method for determining a position (x) of a piston (101) in a cylinder (100; 200; 400; 500), in particular for use in a hydraulic system, with the steps of: sending (S1) ) an ultrasonic signal (108) on a cylinder housing (102) of the cylinder (100; 200; 400; 500) with a cylindrical side wall (103) such that the ultrasonic signal (108) is located along an inner side ( 103a) of the side wall (103) of the cylinder housing (102), receiving (S2) the ultrasonic signal (108) reflected from the piston (101) arranged axially displaceable in the cylinder housing (102), calculating (S3 ) a position (x) of the piston (101) on the basis of a travel time (At) of the ultrasonic signal (108) between outputting and receiving the ultrasonic signal (108).
    [8]
    A method according to claim 7, wherein the sending of the ultrasonic signal (108) takes place through an attachment (106a) which is arranged on the side wall (103) of the cylinder housing (102), the ultrasonic signal (108) ) hits the cylinder housing (102) at an angle of incidence (φΐ), and wherein the angle of incidence (φΐ) is chosen such that the ultrasonic signal (108) at the interface of the attachment (106a) and cylinder housing (102) is broken, that the ultrasonic signal (108) moves along an inner side (103a) of the side wall (103) of the cylinder housing (102).
    [9]
    Method according to claim 7, wherein the sending of the ultrasonic signal (108) takes place by means of at least two electrodes (201a-1, 201a-2), which are arranged comb-like on the side wall (103) of the cylinder housing (102) to be.
    [10]
    The method of claim 7, wherein the sending of the ultrasonic signal (108) is effected by shifting a sliding plate (401) on an outer wall (104) in a radial direction (403), the sliding plate (401) with the outer wall (102) is coupled by friction.
    [11]
    The method according to any of claims 7 to 10, wherein the sending of the ultrasonic signal (108) resp. receiving the reflected ultrasonic signal (108) at different positions of the cylinder housing (102) in a multiplexing method, in particular a time-multiplexing method or a frequency-multiplexing method.
    [12]
    The method of claim 11, wherein the ultrasonic signals (105) are transmitted time-shifted to the different positions of the cylinder housing (102), and wherein a time difference between the output of two ultrasonic signals (108) to different positions of the cylinder housing is greater than the travel time (At) of the ultrasonic signals (108).
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    同族专利:
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    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    US6119579A|1998-03-20|2000-09-19|Caterpillar Inc.|Apparatus and method for detecting piston location within a fluid cylinder of a work machine|
    法律状态:
    优先权:
    申请号 | 申请日 | 专利标题
    DE102015220608.4A|DE102015220608A1|2015-10-22|2015-10-22|A cylinder and method for determining a position of a piston in a cylinder|
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