Pantograph with fracture monitoring

Abstract

The invention relates to a pantograph (4) for an electrically driven vehicle for feeding electrical energy from an overhead line system (3). The pantograph comprises a slide bar (7) for making electrical contact with the slide feed line (2), which slide bar has a slide (9) carried by a slide holding device (8). The compressed air channel (13) is at least partially defined by the slide (9) and is connected to the compressed air supply (11). According to the invention, a pneumatic throttle valve (14) is arranged between the compressed air supply (11) and the slide (9). A test pressure sensor (16) periodically measures an actual test pressure (PDist) downstream of the throttle valve (14), and a feed pressure sensor (15) periodically measures an actual feed pressure (SDist) upstream of the throttle valve (14). The evaluation device (17) is designed to periodically calculate a target test pressure (PDsoll) downstream of the throttle valve (14) in the test volume as a function of the measured actual feed pressure (SDist) as a function of a difference between an air supply mass flow (Qzu) flowing in through the throttle valve (14) and an exhaust gas mass flow (Qab) flowing out into the surroundings (U) through a leak (L) present downstream of the throttle valve (14) in the pressure channel (13). The evaluation device periodically determines a test pressure deviation ([delta] PD) of the actual test pressure (PDist) from the target test pressure (PDsoll) and generates a fault report (E1) if the determined test pressure deviation ([delta] PD) exceeds a first threshold value (S1). As a result, less erroneous fault reports are generated during fracture monitoring.

Description

Technical Field

[0001] The invention relates to a pantograph according to the preamble of claim 1 . Background Art

[0002] The pantograph is designed and arranged for feeding electric energy to an electric or hybrid electric vehicle from an overhead line installation having at least one trolley feeder. The pantograph comprises at least one trolley contact strip for making electrical contact with at least one trolley feeder, the trolley contact strip having a slide carried by a slide holding device. In addition, the pantograph comprises a compressed air channel at least partially defined by the slide and a compressed air supply device connected to the compressed air channel for feeding compressed air. The pantograph also comprises a test pressure sensor for measuring the actual test pressure in the compressed air channel.

[0003] Such a pantograph is known from patent document DE 39 14 675 A1, which discloses a sliding part with a fracture detection device. For this purpose, the sliding contact strip has an airtight channel, which is connected to a device for generating an increased air pressure or gas pressure in the channel and to a detector that signals a pressure reduction. In the event of a fracture or excessive wear of the sliding contact strip, the channel becomes leaky and the fracture or wear is indicated by a pressure reduction. Such a fracture monitoring device also includes brackets arranged on the telescopic feelers according to the invention. These brackets also have corresponding channels, which are connected to the channels of the carbon strips via inserted hoses. The connection to the gas input and the monitoring device can be achieved via a connecting joint in the area of ​​one of the telescopic feelers. However, the brackets of the telescopic feelers can also be manufactured integrally with the sliding contact strip.

[0004] A non-rail-type, electric-driven or hybrid-electric-driven vehicle is known from the publication EP 3 147 152 A1, which has a pantograph for feeding traction power from an overhead line device. The pantograph has a sliding contact strip device that can be raised and lowered, and the sliding contact strip device can make sliding contact with a sliding feeder of the overhead line device extending above the carriageway. The sliding contact strip device has an insulating feeler that protrudes laterally and has a rated breaking position. The sliding contact strip device also has a detection device, which is designed to detect the breaking of the insulating feeler and trigger the automatic descent of the sliding contact strip device. For this purpose, the air channel of the automatic emergency descent can be connected to the emergency descent until the rated breaking position, thereby initiating the emergency descent through a safety relay.

[0005] Known monitoring devices are based on detecting a pressure drop in the pressure channel as a sign of a larger leak in the form of a broken contact strip or a broken telescope feeler. However, the monitoring device may also incorrectly evaluate a drop in the feed pressure on the compressed air input as a detection event. Summary of the invention

[0006] The object of the present invention is therefore to provide a pantograph of the type mentioned in the introduction, the fracture monitoring of which leads to reduced erroneous fault reports.

[0007] According to the invention, the above-mentioned object is achieved by a pantograph of the generic type having the features specified in the characterizing part of claim 1 .

[0008] The pantograph is designed for vehicles with electric drive or hybrid electric drive, for example for road vehicles or rail vehicles, for example as a bow-shaped current collector. The pantograph is used to feed in electrical energy from a single-pole or double-pole overhead line device, which has a sliding contact feeder for rail vehicles and two sliding contact feeders designed as a go conductor and a return conductor for road vehicles. Each contact pole of the pantograph includes at least one sliding contact bar for making electrical contact with the corresponding sliding contact feeder, but each contact pole can also include two sliding contact bars arranged one after the other in the direction of travel. Each sliding contact bar has a sliding member carried by a sliding member holding device, and the sliding member is preferably made of carbon. One or more sliding contact bars of the contact pole can be supported on a rocker device respectively, and the rocker device can be supported by a support frame that can be erected in a telescopic manner. The pantograph includes a compressed air channel, which is at least partially defined by a sliding member, and a compressed air supply device for feeding compressed air is connected to the compressed air channel. A compressed air channel extends from the compressed air supply device into each of the at least one contact strip and is defined there at least partially by the respective slide. The pantograph further comprises a test pressure sensor for measuring an actual test pressure in the compressed air channel.

[0009] According to the invention, the pantograph comprises a pneumatic throttle valve, which is arranged in a compressed air channel between a compressed air supply device and a slide, wherein a test pressure sensor periodically measures an actual test pressure in the compressed air channel downstream of the throttle valve. The pantograph also comprises a feed pressure sensor, which is used to periodically measure an actual feed pressure in the compressed air channel upstream of the throttle valve. In addition, the pantograph also comprises an analysis device, which is designed to periodically calculate a rated test pressure in the compressed air channel downstream of the throttle valve based on the measured actual feed pressure according to the difference between a supply air mass flow and an exhaust gas mass flow, the supply air mass flow flowing in through the throttle valve and the exhaust gas mass flow flowing out to the environment through a leak in the pressure channel downstream of the throttle valve. The analysis device is also designed to periodically determine a test pressure deviation between the actual test pressure and the rated test pressure and to generate a fault report if the determined test pressure deviation exceeds a first threshold value.

[0010] Periodicity here means continuously at discrete, fixed time intervals, for example once every 5 ms. The time intervals can also be determined by a clock of a pantograph control device, which controls a compressed air supply device and a lifting device for raising and lowering at least one contact strip.

[0011] The evaluation device comprises means known per se for electronic data processing, such as a computer unit and a data memory in which a calculation algorithm is stored for calculating a target test pressure in a test volume, ie, a volume of the compressed air channel downstream of the throttle valve.

[0012] The difference between the supply air mass flow flowing in through the throttle valve and the exhaust air mass flow of the compressed air flowing out through the leakage is included as an important variable for the present invention in the calculation of the set test pressure. The supply air mass flow is determined by the current actual feed pressure upstream of the throttle valve, the flow cross section of the throttle valve and the actual test pressure in the test volume. The exhaust air mass flow is determined by the actual test pressure in the test volume, the size of the leakage in the test volume and the ambient air pressure in the surroundings.

[0013] The calculation of the mass flow of compressed air is based on a flow model of the throttle valve and the leakage, wherein a distinction is made between subcritical and supercritical flows depending on the pressure ratio upstream and downstream of the throttle valve or the leakage. Even if the sliding part is intact, it can be assumed that a leak of smaller size exists due to the actual leakiness of the compressed air channel. The analysis unit identifies cracks or breaks on the sliding part based on the size of the test pressure deviation, whose gap width corresponds to, for example, a flow cross section of 2 mm and above. Since the flow model continuously calculates the behavior of the rated test pressure in the test volume based on the measured actual feed pressure upstream of the throttle valve, the determined test pressure deviation is insensitive to fluctuations in the feed pressure. Such pressure fluctuations occur, for example, when other consumers, such as the pneumatic lifting device of the pantograph, are connected to the compressed air supply. By taking into account the actual feed pressure, it is possible to avoid the pressure drop in the pressure channel caused by a drop in the feed pressure or temperature fluctuations on the compressed air supply being erroneously interpreted as a break detected in the sliding part. This reduces the number of erroneous fault reports.

[0014] In an advantageous embodiment of the pantograph according to the invention, the analysis device is designed to periodically calculate the actual rate of change of the actual test pressure based on temporally successive measurements of the actual test pressure, calculate the rated rate of change of the calculated rated test pressure based on temporally successive calculations of the rated test pressure, determine the rate of change deviation of the actual rate of change from the rated rate of change, and generate a fault report if the determined rate of change deviation exceeds a second threshold value. The corresponding rate of change indicates how fast the rated test pressure or the actual test pressure changes, which mathematically corresponds to the first derivative of the test pressure with respect to time. By monitoring the rate of change deviation for exceeding the second threshold value, critical manifestations of the test pressure in the test volume can be identified earlier than with known solutions that only compare the static pressure in the pressure channel with a fixed rated value. By means of the described embodiment, a response time in the range of 10 ms to 40 ms can be achieved. This is crucial in the case where the control device of the pantograph must react quickly to the generated fault report in order to loosen the contact between the sliding member and the sliding feeder of the overhead line equipment.

[0015] In another advantageous embodiment of the pantograph according to the invention, the analysis device is designed to calculate the supply air mass flow as a function of the measured actual feed pressure, the measured actual test pressure and the flow coefficient of the throttle valve, and to calculate the exhaust air mass flow as a function of the measured actual test pressure, the ambient air pressure and the flow coefficient of the leakage section. The flow model stored in the analysis unit is based on the mass flow Q=dm / dt of the compressed air through the nozzle, which is determined by the corresponding prepressure on the upstream side, the back pressure on the downstream side and the narrowest cross-section of the nozzle. For this purpose, equations for determining the mass flow and different approximate assumptions for simplifying the equations are known, for example, from https: / / de.wikipedia.org / wiki / Düsenströmung. The specific simplified form is given, for example, by the following equation:

[0016] For P2>1 / 2·P1, Q=514·KV·[(P1–P2)·P2 / ρN·T] 1 / 2 ,

[0017] For P2<1 / 2·P1, Q=257·KV·P1·[ρN·T] -1 / 2 ,

[0018] in,

[0019] Q: mass flow, in kg / h

[0020] P1: pre-pressure upstream of the nozzle, in bar,

[0021] P2: back pressure downstream of the nozzle, in bar,

[0022] KV: flow coefficient, unit is kg / h

[0023] ρN: density, in kg / m 3 ,as well as

[0024] T: temperature, in K.

[0025] For temperature, you can use 297K, and for density, you can use 1.2 kg / m 3 . Flow coefficient K of throttle valve and leakage part V It is determined empirically for a pantograph of one construction mode and therefore remains constant. For throttle valves, the actual feed pressure is used as the pre-pressure and the actual test pressure as the back pressure. For leaks, the actual test pressure is used as the pre-pressure and the ambient air pressure as the back pressure.

[0026] In another advantageous embodiment, the pantograph according to the present invention also includes a pneumatic lifting device for raising and lowering at least one sliding contact strip, and a control device connected to the analysis device for controlling the lifting device. The analysis device is designed to transmit the generated fault report to the control device, and trigger the descent of at least one sliding contact strip and / or generate a driver instruction when transmitting the fault report. The lifting device can have a retractable rack carrying the sliding contact strip, which can be erected by an air bellows. The air bellows can be provided with compressed air by a compressed air supply device. The lifting device is electrically controlled by the control device of the pantograph so that the lifting device enters or exits the operating state and triggers the raising or lowering of the sliding contact strip. If the analysis device transmits the generated fault report to the control device, the control device can prevent the lifting of the sliding contact strip, or lower the sliding contact strip in contact with the sliding feeder to prevent the damaged pantograph with a sliding part with a crack or a break from contacting the sliding feeder.

[0027] In another advantageous embodiment of the pantograph according to the invention, the analysis device is designed to identify the situation that the test pressure deviation exceeds the first threshold value and / or the rate of change deviation exceeds the second threshold value during the increase of the feed pressure from the ambient pressure to the nominal feed pressure as a blockage in the pressure channel and generate a corresponding fault report. This blockage in the pressure channel may be caused by production errors or assembly errors and may hinder the correct determination of the test pressure deviation and / or the rate of change deviation, thereby hindering the fault identification of "compressed air escapes from a break or crack, for example, from a break or crack in a sliding part". This blockage reduces the test volume in the pressure channel, so that the measured actual test pressure increases faster than the calculated rated test pressure. This is even more applicable to the rate of change of the test pressure. Therefore, for example, when the feed pressure increases to the nominal feed pressure, the analysis device can quickly output the existing fault indication and prompt the control device to avoid the rise of the sliding contact strip by means of the fault report. It is thus possible to find a fault, such as a blockage in the pressure channel, which makes it impossible to achieve the actual purpose, such as identifying a break in the sliding part or a crack in the sliding part. If the fault is not detected, safety risks arise, such as damage to the vehicle and / or the overhead line equipment due to contact between the contactor and the damaged sliding part. According to the present invention, these safety risks are compensated in other ways, such as automatically preventing the contact strip from rising or issuing a corresponding warning to the vehicle driver.

[0028] In another advantageous embodiment of the pantograph according to the invention, the analysis device is designed to identify the situation in which the test pressure deviation exceeds a first threshold value and / or the rate of change deviation exceeds a second threshold value after the nominal feed pressure is reached as a crack or break in the sliding part, and to generate a corresponding fault report. If a crack appears in the sliding part during vehicle operation or the sliding part breaks, for example, when the sliding part is severely worn and there is no remaining wear reserve, the actual test pressure drops from its nominal value to a greater extent than the calculated rated test pressure. This drop is recognized early because the rate of change deviation exceeds the second threshold value accordingly, so that the reaction time between the occurrence of the fault and the triggering of the intervention by the control device is very short. As a result, the contact between the sliding part and the sliding feeder can be interrupted by lowering the pantograph, avoiding or reducing indirect damage that may be caused by damage to the sliding part.

[0029] The invention also relates to an electrically driven or hybrid electrically driven vehicle, in particular a road vehicle, which is equipped with a pantograph according to any of the preceding claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Further features and advantages of the invention are apparent from the following description of exemplary embodiments with reference to the accompanying drawings, in which:

[0031] Figure 1A road vehicle with a pantograph according to the invention is shown in a front view,

[0032] Figure 2 A timeline diagram showing the nominal test pressure and the actual test pressure during which the feed pressure is correctly increased to the nominal value,

[0033] Figure 3 Shown with Figure 2 The timeline diagram of the rated rate of change and the actual rate of change of the corresponding test pressure,

[0034] Figure 4 Shown with Figure 2 Corresponding timeline diagram of test pressure deviation,

[0035] Figure 5 Shown with Figure 4 The corresponding timeline graph of the rate of change deviation,

[0036] Figure 6 A timeline graph showing nominal test pressure and actual test pressure during feed pressure rise when there is a blockage in the pressure channel,

[0037] Figure 7 Shown with Figure 6 A timeline graph of the corresponding rated and actual rates of change, and

[0038] Figure 8 A timeline graph of the actual test pressure and the actual rate of change of the test pressure from the nominal feed pressure when a crack suddenly appears in the slide is shown. DETAILED DESCRIPTION

[0039] according to Figure 1, an electric or hybrid electric road vehicle 1 designed as a heavy commercial vehicle, for example, uses an electrified lane of a carriageway, for example a multi-lane highway, above which a bipolar overhead line device 3 is provided with two sliding contact wires 2 designed as a go conductor and a return conductor. In order to feed in electrical energy from the overhead line device 3, the road vehicle 1 has a pantograph 4, which has two sliding contact strips 4 arranged one after the other for each contact pole along the longitudinal direction of the vehicle, which are used to make electrical contact with the corresponding sliding contact wires 2. The pantograph 4 includes a support frame 5 that can be erected in a telescopic manner, and the support frame has, for example, a lower arm and two upper arms that are hinged to each other and to the vehicle. Each upper arm has a rocker 6 that can rotate around the transverse axis of the vehicle, and a pair of sliding contact strips 7 are elastically supported on each rocker. Each sliding contact strip 7 has an elongated sliding member 9 made of graphite and supported by a sliding member holding device 8. The downwardly bent telescopic feeler is arranged at the end of the side of the sliding contact strip. The support frame 5 is coupled to a lifting device 10 designed as an air bellows to raise and lower the contact strip 7. The lifting device 10 is fed with compressed air by a compressed air supply 11. For this purpose, the pantograph 4 includes a control device 12, which electrically controls a valve to connect the lifting device 10 for lifting the support frame 5 to the compressed air supply 11, or to isolate the lifting device 10 from the compressed air supply 11 so that the support frame 5 can be lowered by gravity drive. The pantograph 4 includes a compressed air channel 13 connected to the compressed air supply 11. The compressed air channel 13 can be partially composed of independent compressed air lines that are optionally flexibly arranged along the support frame 5, branched and extend in each contact strip 7. In the contact strip 7, the compressed air channel 13 is respectively at least partially defined by the corresponding sliding member 9.

[0040] according to Figure 1 The pantograph 4 further comprises a pneumatic throttle valve 14, which is arranged in the compressed air channel 13 between the compressed air supply 11 and the slide 9. A feed pressure sensor 15 is connected to the compressed air channel 13 for periodically measuring the actual feed pressure SDist upstream of the throttle valve 14. In addition, a test pressure sensor 16 is connected to the compressed air channel 13 for periodically measuring the actual test pressure PDist downstream of the throttle valve 14 in the test volume.

[0041] according to Figure 1The pantograph 4 further comprises an analysis device 17, which is designed to periodically calculate a setpoint test pressure PDsoll in the compressed air channel 13 downstream of the throttle valve 14 as a function of the measured actual feed pressure SDist according to the difference between the supply air mass flow Qzu flowing in through the throttle valve 14 and the exhaust gas mass flow Qab flowing out into the environment U through the leakage L present in the pressure channel 13 downstream of the throttle valve 14. The analysis device 17 is also designed to periodically determine a test pressure deviation ΔPD between the actual test pressure PDist and the setpoint test pressure PDsoll and to generate an error message E1 if the determined test pressure deviation ΔPD exceeds a first threshold value S1. Periodicity here means that it is carried out continuously at fixed time intervals, for example once every 5 ms. The time interval can also be given by the clock of the control device 12 of the pantograph 4. For this purpose, the analysis device 17 comprises known means for electronic data processing, for example a computer unit and a data memory not shown in detail, in which a calculation algorithm for calculating the setpoint test pressure PDsoll in the test volume is stored.

[0042] The difference between the supply air mass flow Qzu flowing in through the throttle valve 14 and the exhaust air mass flow Qab of the compressed air flowing out through the leakage L is included in the calculation of the set test pressure PDsoll as an important variable for the present invention. The supply air mass flow Qzu is determined by the current actual feed pressure SDist upstream of the throttle valve 14, the flow cross section 14 of the throttle valve 14 and the actual test pressure PDist in the test volume. The exhaust air mass flow Qab is determined by the actual test pressure PDist in the test volume, the size of the leakage L in the test volume and the ambient pressure UD in the environment U. The calculation of the mass flows Qzu and Qab of the compressed air is based on a flow model of the throttle valve 14 and the leakage L, wherein a distinction is made between subcritical and supercritical flows depending on the pressure ratio upstream and downstream of the throttle valve 14 or the leakage L. The analysis device 17 is preferably designed to calculate the supply air mass flow Qzu as a function of the measured actual feed pressure SDist, the measured actual test pressure PDist and the flow coefficient KV14 of the throttle valve 14, and to calculate the exhaust gas mass flow Qab as a function of the measured actual test pressure Pdist, the ambient pressure DU and the flow coefficient KVL of the leakage L. The flow model stored in the analysis unit 17 is based on an approximate equation for the mass flow Q=dm / dt of the compressed air through the nozzle. This mass flow is approximately determined by the corresponding upstream prepressure, the downstream back pressure and the narrowest cross section of the nozzle:

[0043] For P2>1 / 2·P1, Q=514·KV·[(P1–P2)·P2 / ρN·T] 1 / 2 ,

[0044] For P2<1 / 2·P1, Q=257·KV·P1·[ρN·T] -1 / 2 ,

[0045] in,

[0046] Q: mass flow, in kg / h,

[0047] P1: pre-pressure upstream of the nozzle, in bar,

[0048] P2: back pressure downstream of the nozzle, in bar,

[0049] KV: flow coefficient, unit is kg / h

[0050] ρN: standard density in kg / m3, and

[0051] T: temperature, in K.

[0052] 297K can be used for temperature and 1.2kg / m3 can be used for density. The flow coefficient KV of the throttle valve 14 and the leakage portion L is determined empirically for a pantograph 4 of a construction mode and remains unchanged. For the supply air mass flow Qzu through the throttle valve 14, the actual feed pressure SDist is used as the pre-pressure P1 and the actual test pressure PDist is used as the back pressure P2; for the exhaust gas mass flow Qab through the leakage portion L, the actual test pressure PDist is used as the pre-pressure P1 and the ambient pressure UD is used as the back pressure P2.

[0053] Even if the slide 9 is intact, it can be assumed that a leak of smaller size is present due to the actually realized leakiness of the compressed air channel 13. The analysis unit 17 detects cracks or breaks on the slide 9 by means of the size of the test pressure deviation ΔPD, the gap width of which corresponds to, for example, a flow cross section of 2 mm and above. Since the flow model continuously calculates the behavior of the setpoint test pressure PDsoll in the test volume as a function of the measured actual feed pressure SDist upstream of the throttle valve 14, the determined test pressure deviation ΔPD is insensitive to fluctuations in the feed pressure SD. Such pressure fluctuations occur, for example, when other consumers, such as a pneumatic lifting device 10, are connected to the compressed air supply 11. By taking into account the actual feed pressure SDist, it is possible to avoid a pressure drop in the pressure channel 13 caused by a feed pressure drop 11 or temperature fluctuations on the part of the compressed air supply being erroneously interpreted as a detection of a break in the slide 9. This reduces the number of erroneous fault reports.

[0054] The analysis device 17 is also designed to periodically calculate the actual rate of change PD'ist of the actual test pressure PDist based on temporally successive measurements of the actual test pressure PDist, calculate the rated rate of change PD'soll of the calculated rated test pressure PDsoll based on temporally successive calculations of the rated test pressure PDsoll, determine the rate of change deviation ΔPD' between the actual rate of change PD'ist and the rated rate of change PD'soll, and generate a fault report E2 when the determined rate of change deviation ΔPD' exceeds a second threshold value S2. The corresponding rate of change indicates how fast the rated test pressure PDsoll or the actual test pressure PDist changes, which mathematically corresponds to the first-order derivative of the test pressure with respect to time. By monitoring the rate of change deviation ΔPD' for exceeding the second threshold value S2, critical manifestations of the actual test pressure PDist in the test volume can be identified earlier than the known solution of only comparing the static pressure in the pressure channel with a fixed rated value. This makes it possible to achieve a response time in the range of 10 ms to 40 ms. This is of particular importance if the control device 12 of the pantograph 4 must react quickly to a generated fault message E2 in order to release the contact between the slider 9 and the trolley feeder 2 of the overhead line system 3 .

[0055] The lifting device 10 is electrically controlled by means of the control device 12 of the pantograph 4 so as to put the lifting device into or out of the operating state and trigger the raising or lowering of the trolley bar 7. If the analysis device 17 transmits the generated fault report E1 or E2 to the control device 12, the control device can prevent the raising of the trolley bar 7 or lower the trolley bar in contact with the trolley feeder to prevent the damaged pantograph 4 with a cracked or broken sliding member 9 from contacting the trolley feeder 2.

[0056] The analysis device 17 is also designed to identify the situation that the test pressure deviation ΔPD exceeds the first threshold value S1 and / or the change rate deviation ΔPD' exceeds the second threshold value during the increase of the feed pressure SD from the ambient pressure UD to the nominal feed pressure SDnenn as a blockage in the pressure channel 13 and generate a corresponding fault report E3. This blockage in the pressure channel 13 may be caused by production or assembly errors and may hinder the correct determination of the test pressure deviation ΔPD and / or the change rate deviation ΔPD', thereby hindering the fault identification of "compressed air escapes from a break or crack, for example, from a break or crack in a sliding part". This blockage reduces the test volume in the pressure channel 13, so that the measured actual test pressure PDist increases faster than the calculated rated test pressure PDsoll. This is more applicable to the change rate PD' of the test pressure PD. Therefore, for example, when the feed pressure SD increases to the nominal feed pressure SDnenn, the analysis device 17 can quickly output the existing fault indication and prompt the control device 12 to avoid the rise of the sliding contact strip 7 with the help of the fault report E3. This makes it possible to detect a fault, such as a blockage in the pressure channel 14, which makes it impossible to achieve the actual purpose, such as identifying a break in the slide 9 or a crack in the slide 9. If the fault is not detected, safety risks arise, such as damage to the vehicle 1 and / or the overhead line system 3 due to contact between the contact wire 2 and the damaged slide 9, which safety risks are compensated in other ways according to the invention, for example, by automatically preventing the lifting of the contact strip 7 or issuing a corresponding warning W to the vehicle driver.

[0057] The analysis device is particularly designed to identify the situation that the test pressure deviation ΔPD exceeds the first threshold value S1 and / or the change rate deviation ΔPD' exceeds the second threshold value after the nominal feed pressure SDnenn is reached as a crack or break of the sliding member 9, and generate a corresponding fault report E1 or E2. If a crack 9 appears in the sliding member 9 during the operation of the vehicle 1 or the sliding member 9 breaks, for example, when the sliding member 9 is severely worn and there is no remaining wear reserve, the actual test pressure PDist drops from its nominal value to a greater extent than the calculated setpoint test pressure PDsoll. This drop is recognized early because the change rate deviation ΔPD' exceeds the second threshold value S2 accordingly, so that the reaction time between the occurrence of the fault and the triggering of the intervention by the control device 12 is very short. As a result, the contact between the sliding member 9 and the contact feeder 2 can be interrupted by lowering the pantograph 4, and indirect damage that may be caused by damage to the sliding member 9 can be avoided or reduced.

[0058] Described below Figures 2 to 8 In FIG. 1 , the mode of operation of the analysis device 17 according to the invention is explained by means of a time diagram of periodically recorded measured values ​​and periodically calculated comparison variables.

[0059] Figure 2 It is shown how the measured actual test pressure PDist and the calculated setpoint test pressure PDsoll develop over time t in the test volume downstream of the throttle valve 14 when the feed pressure SD is increased by means of the compressed air supply 11. The measured actual test pressure PDist is initially at the level of the ambient pressure UD and increases from the start of the system at approximately t=16.7 seconds until the nominal feed pressure SDnenn is reached in the test volume at approximately t=19.0 seconds. During the operation of the pantograph 4, the pressure in the test volume remains at this level, but may fluctuate slightly, for example around t=20.4 seconds. Figure 2 It is shown that when the pressure channel 13 is unobstructed, the measured actual test pressure PDist is almost completely consistent with the calculated setpoint test pressure PDsoll, and even the increase around t=20.4 seconds is almost completely consistent, and the increase is caused by the fluctuation of the actual feed pressure SDist. Figure 4 The test pressure deviation ΔPD between the actual test pressure PDist and the rated test pressure PDsoll is also shown, and the test pressure deviation does not exceed a preset first threshold value S1. Figure 3 , the actual change rate PD'ist of the measured actual test pressure PDist also follows the nominal change rate PD'soll of the calculated nominal test pressure PDsoll, wherein, due to discrete measurements, the actual change rate PD'ist is scattered around the curve of the calculated nominal change rate PD'soll approximately every 5 ms. Figure 5 , when the pressure channel 13 is not blocked, the change rate deviation ΔPD' between the actual change rate PD'ist and the set change rate PD'soll does not exceed the preset second threshold value S2. When there is a blockage in the pressure channel 13, the situation is different. Figure 6 , the actual test pressure PDist increases faster than the rated test pressure PDsoll, and the test pressure deviation ΔPD exceeds the first threshold value S1 at the marked time point. Figure 7 The corresponding change process of the rate of change of the actual rate of change PD'ist and the setpoint rate of change PD'soll, the rate of change deviation ΔPD' between the actual rate of change PD'ist and the setpoint rate of change PD'soll has exceeded the second threshold value S2 at the same earlier time point. Therefore, by monitoring the second threshold value S2, the failure of the fracture recognition caused by the blockage in the pressure channel 13 can be detected earlier.

[0060] Figure 8 The actual test pressure PDist (PDist) is shown starting from a normal operation with a nominal feed pressure SDnenn in the test volume in the event of a leak in the pressure channel 13, for example a rupture in the slide 9. Figure 8The upper curve in FIG. 2 decreases and the actual rate of change PD'ist of the actual test pressure PDist decreases faster. Since the rates of change PD'ist and PD'soll decrease faster than the test pressures PDist and PDsoll, the rate of change deviation ΔPD' exceeds the second threshold value S2 earlier than the test pressure deviation ΔPD exceeds the first threshold value S1. The reaction time of the control intervention is thereby shortened by monitoring the second threshold value S2.

Claims

1. A pantograph (4) for an electric or hybrid electric vehicle, in particular a road vehicle (1), for feeding in electrical energy from an overhead line system (3) having at least one trolley feeder (2), the pantograph comprising - at least one contact strip (7) for making electrical contact with at least one trolley supply line (2) and having a slide (9) carried by a slide holder (8), - a compressed air channel (13) which is at least partially defined by the slide (9), - a compressed air supply (11) which is connected to the compressed air channel (13) and is used to feed compressed air, and - a test pressure sensor (16) for measuring the actual test pressure (PDist) in the compressed air channel (13), Features - a pneumatic throttle valve (14) arranged in a compressed air channel (13) between the compressed air supply (11) and the slide (9), wherein the test pressure sensor (16) periodically measures an actual test pressure (PDist) in the compressed air channel (13) downstream of the throttle valve (14), - a feed pressure sensor (15) for periodically measuring the actual feed pressure (SDist) in the compressed air channel (13) upstream of the throttle valve (14), and - an analysis device (17) designed to - periodically calculating a setpoint test pressure (PDsoll) downstream of the throttle valve (14) in the compressed air channel (13) as a function of the measured actual feed pressure (SDist) from the difference between a supply air mass flow (Qzu) which flows in through the throttle valve (14) and an exhaust gas mass flow (Qab) which flows out into the environment (U) through a leakage (L) present in the pressure channel (13) downstream of the throttle valve (14), - periodically determine the test pressure deviation (ΔPD) of the actual test pressure (PDist) from the nominal test pressure (PDsoll), and - generating a fault message (E1) if the determined test pressure deviation (ΔPD) exceeds a first threshold value (S1).

2. The pantograph (4) according to claim 1, wherein: The analysis device (17) is designed to: - periodically calculating the actual rate of change (PD'ist) of the actual test pressure (PDist) based on temporally successive measurements of the actual test pressure (PDist), - calculating a set rate of change (PD'soll) of the calculated set test pressure (PDsoll) from the temporally successive calculations of the set test pressure (PDsoll), - determine the rate of change deviation (ΔPD') of the actual rate of change (PD'ist) from the set rate of change (PD'soll), and - generating a fault message (E2) if the determined rate of change deviation (ΔPD′) exceeds a second threshold value (S2).

3. The pantograph (4) according to claim 1 or 2, wherein: The analytical device is designed to: - calculate the supply air mass flow (Qzu) from the measured actual feed pressure (SDist), the measured actual test pressure (PDist) and the flow coefficient (KV14) of the throttle valve (14), and - Calculate the exhaust gas mass flow (Qab) from the measured actual test pressure (PDist), the ambient pressure (UD) and the flow coefficient (KVL) of the leakage (L).

4. The pantograph (4) according to any one of the preceding claims, further comprising: - a pneumatic lifting device (10) for raising and lowering at least one contact strip (7), and - a control device (12) connected to the analysis device (17) for controlling the lifting device (10), - in, The analyzing device (17) is designed to transmit the generated fault report (E1, E2) to the control device (12), and - wherein the control device (12) is designed to trigger the lowering of at least one contact strip (7) and / or to generate a driver instruction (W) when transmitting a fault message (E1, E2).

5. A pantograph (4) according to any one of the preceding claims, wherein: The analysis device (17) is designed to identify a situation in which a test pressure deviation (ΔPD) exceeds a first threshold value (S1) and / or a rate of change deviation (ΔPD') exceeds a second threshold value, which occurs during an increase in the feed pressure (SDist) from the ambient pressure (UD) to the nominal feed pressure (SDnenn), as a blockage in the pressure channel (13) and to generate a corresponding fault message (E3).

6. A pantograph (4) according to any one of the preceding claims, wherein: The analysis device (17) is designed to identify a test pressure deviation (ΔPD) exceeding a first threshold value (S1) and / or a rate of change (ΔPD') deviation exceeding a second threshold value (S2) occurring after a nominal feed pressure (SDnenn) has been reached as a crack or break in the sliding part (9) and to generate a corresponding fault report (E1, E2).

7. An electrically or hybrid-electrically driven vehicle, in particular a road vehicle (1), having a pantograph (4) according to any one of the preceding claims.

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