DE102015209867A1 - Method for condition monitoring of at least one planetary gear of a planetary gear - Google Patents

Abstract

The invention relates to a method for condition monitoring of at least one planetary gear (10, 30) of a planetary gear (1), wherein the at least one planetary gear (10, 30) is rotatably mounted in the planetary gear (1), characterized in that in a Vorbeidrenhen the at least one planetary gear (10, 30) at least one sensor (5) by means of the at least one sensor (5) at least signal (S1, S2) is generated, at least one actual signal feature of at least one generated signal (S1, S2) is compared at least in each case a predetermined desired signal feature and - is closed to an error when the at least one predetermined nominal signal feature and the at least one actual signal feature of at least one generated signal (S1, S2) is not identical.

Description

The invention relates to a method for condition monitoring of at least one planetary gear of a planetary gear, wherein the at least one planet gear is rotatably mounted in the planetary gear.

A planetary gear of the aforementioned type can be used in many areas of the drive technology because of its favorable properties and because of its possible use in particular as a superposition, gear, shift or branch. This type of transmission has prevailed particularly in vehicle construction.

An essential feature for a behavior of a planetary gear is its degree F. The degree of a transmission indicates how many independent motion variables must be specified as known, so that its state of motion is clearly determinable. While stationary gearboxes are always forced (F = 1), simple planetary gear ratios of F = 1 or F = 2, compound planetary gears can have degrees of operation of F ≥ 1.

Constructively, a planetary gear can be divided into a simple planetary gear with a bridge with at least one planet and one or two central gears and a composite planetary gear with several simple planetary gears. Simple planetary gears with coaxial position of the connection shafts are also referred to as returning planetary gears. Planetary gears with only one central gear and a non-coaxial rotating connecting shaft are also referred to as open planetary gear. Is simplified in a compound planetary gear construction costs by the union of webs, the same size central wheels and / or the same size planetary gears, so we speak of reduced planetary gears.

After use, a planetary gear u. a. in a transmission gear and a superposition gear, wherein a transmission gear is a simple or compound planetary gear with degree F = 1 and wherein a superposition gear is a simple or compound planetary gear with degree of F ≥ 2 for superposition of speeds or powers. Common names for a superposition gear are also differential, collective, distribution and differential gear.

After use, a planetary gear can also u. a. differ in a manual transmission and reverse gear.

A planetary gear can also be subdivided according to its web movement. If the web is stationary in a simple planetary gear, the running degree F = 1. This gear is known as a stationary gear. Planetary gear is called a simple planetary gear with a circumferential ridge (F = 1 or F = 2) or a compound planetary gear with at least one circumferential ridge (F ≥ 1).

Further subdivisions after u. a. Number of running connection shafts, sign of the stationary gear ratio, variable stationary gear ratio or gearbox combinations are possible.

A sensor in a planetary gear, can fulfill several functions: It can detect one or more operating conditions and / or one or more predeterminable values and / or convert physical quantities and / or chemical quantities into electrical signals. The sensor acts as a kind of link between the planetary gear z. B. a vehicle with its complex functions and electronic control units as processing units. The sensor may include a matching circuit that can condition and amplify a signal for further processing by a controller. Sensors today can have a high level of integration, i. h., that many functions, such. As signal conditioning, analog-to-digital conversion, self-calibration functions and microprocessor can already be accommodated in the sensor.

A method for automatic condition monitoring of one or more planetary gears in a planetary gear is desirable, for. B. constructive weaknesses such. As a fraction of one or a fraction in the planet carrier or interruptions in downstream waves, z. B. to be able to detect a break in a subsequent load path, since a mechanical fracture is critical to safety and the function of the planetary gear would no longer be guaranteed. By monitoring the condition is z. B. an initiation of a safe operating condition and / or an output to an output device possible.

Out "Conventional Powertrain and Hybrid Drives" (Ed. Konrad Reif, Vieweg + Teubner Verlag, 2010, p. 150ff.) a general application of a sensor as a transmission speed sensor is described. The sensor can be integrated in a transmission control module or designed as a "stand-alone" version. The transmission speed sensor may have a differential 2-wire current-effect Hall effect IC and is connected to a voltage source for operation. The transmission speed sensor can detect the speed signal from ferromagnetic gears, punching plates or applied multipoles, taking advantage of the Hall effect and providing a signal having a constant amplitude independent of the speed. For signal output, the supply current is modulated in the rhythm of the increment signal. The current modulation can then be converted in the control unit with a measuring resistor into a signal voltage.

Furthermore, it is known from the prior art to use sensors in planetary gears, especially in differential gears, to be able to determine, for example, a speed of a ring gear. From the US2007197338A1 It is known to detect a position of a differential housing or a shaft arranged thereon by means of a sensor. From the JP2007154939A2 It is known to use sensors in bevel gear differential gears to constantly check a state of the same. From the EP0939247A2 It is known to detect the differentiation conditions between the bevel gear and the drive bevel gear in a differential by means of a sensor.

Against this background, it is an object of the present invention to provide a cost-effective and reliable method for condition monitoring of at least one planetary gear of a planetary gear.

This object is achieved according to the invention in that at least one signal (S ₁ , S ₂ ) is generated when the at least one planet wheel moves past at least one sensor by means of the at least one sensor, at least one actual signal feature of the at least one generated signal (S ₁ , S ₂ ) is compared with at least one predetermined nominal signal characteristic in each case and is concluded on an error if the at least one predetermined nominal signal feature and the at least one actual signal feature of the at least one generated signal (S ₁ , S ₂ ) is not identical.

If a planetary gear rotates around the second axis of rotation, it rotates radially spaced therefrom. If the at least one planetary gear moves past the at least one sensor, the at least one sensor generates at least one signal which represents the actual signal of the at least one planetary gear. Thus, a signal can be generated per complete revolution that represents a rotation about the second axis of rotation. The non-identity of the signal characteristics can, for. B. in the form of a signal frequency change.

With the method according to the invention a detection of a malposition of the at least one planetary gear is made possible. Thus, in particular, a tilting of the planet carrier or of the web together with the planetary gear and / or a rotation of the planetary gear around its own axis of rotation can lead to problems, in particular malfunctions due to z. B. of breaks in the planet carrier or breaks in the load paths of the transmission, which can be detected early with the method according to the invention. The tilting or rotation about its own axis of rotation is a reaction to a fault in the planetary gear, the cause of a mechanical break, z. B. may be a break in or a planetary carrier or a break in the subsequent load path.

It has also been found that the method according to the invention can help prevent consequential damage and better plan maintenance and / or repair measures. As a result, cost advantages may arise insofar as that early on z. B. a defective planetary gear and / or a defective planet carrier can be replaced before z. B. the entire planetary gear takes damage. Costs can also be reduced insofar as due to this predictability a just-in-time ordering of corresponding components is made possible.

It has been found that a monitoring concept can be imaged with the method according to the invention, can work redundantly, diversitively and without preprocessing of the sensor signals.

For the condition monitoring is irrelevant in which of the two directions, the at least one planet rotates the second axis of rotation. However, a method is particularly preferred in which additionally a first and second direction of rotation of the at least one planetary gear is detected. This can be done for example by means of another sensor. The direction of rotation about the second axis of rotation can be determined on the basis of angle information. For example, in a planetary gear in a rotation of a planetary gear about the second axis of rotation, a first angle to a second angle, wherein the second angle z. B. can be greater than the first angle or vice versa, wherein the first small angle of the detection of the respective planetary gear and the second large angle of the respective pause between two planetary gears can correspond or vice versa. Thus, the direction of rotation can be derived from knowledge of a mounting situation.

Under installation situation is a determination to understand whether a difference of the first and second angle with a positive sign a round trip in a first direction, z. B. left-handed, of two directions of rotation and negative sign in a second direction, z. B. clockwise, corresponds. Or whether the positive sign represents a rotation in the second direction, clockwise, and in the case of a negative sign a circulation in the first direction, counterclockwise.

Also preferred is a method in which the at least one planetary gear has a marking body which extends over an angular range in the circumferential direction and has at least one interruption and signal generation is prevented when the at least one interruption is detected by the at least one sensor. By means of the marker body is in a structurally simple way a better detection of the planetary gear when it passes the sensor, as well as a better detection of a compensating movement possible, d. H. a rotational movement of the planetary gear about its own axis of rotation. The marker body is firmly connected to the planet, so that can be deduced from the detection of the marker body on the movement of the planetary gear. The interruption can z. Example, a recess or gap, which can be directed to the sensor with a rotation of the at least one planetary gear about the first axis of rotation, which is at the same time its own. This rotation about the first axis of rotation can, for. B. represent a compensation movement to compensate for tension in the output axles. If the interruption is directed to the sensor and the planetary gear rotates past the sensor, then the planetary gear is not detected by the sensor but the signal generation is prevented. Failure of a signal can then be considered an error, eg. B. as a rotation about its own axis of rotation, are issued.

In addition, a method is preferred in which an amplitude of the at least one signal is a predetermined signal feature.

Further preferred is a method in which a signal width of the at least one signal is a predetermined signal feature. The signal width or pulse width is a time range that is between a signal start and a signal end of the same signal. This time range corresponds to an angular range covered by the planetary gear during rotation about the second axis of rotation.

In addition, a method is preferred in which a width of a signal pause is a predetermined signal feature. The width of the signal pause is a time interval that is between two consecutive signals, d. H. between a signal end of a first signal and a signal start of a subsequent second signal. This time range likewise corresponds to an angular range which the planetary gear covers during the rotation about the second axis of rotation, this time range or angle range usually being greater than the time range or angular range representing the signal width.

Furthermore, a method is preferred in which an error is concluded when a ratio of at least one signal width and at least one width of a signal pause does not correspond to a predefined expected value.

Furthermore, a method is preferred in which an error is concluded when a first ratio of at least one first signal width and at least one first width of a first signal pause does not correspond to a second ratio of at least one second signal width and at least one second width of a second signal pause. The advantage is that speed changes can be taken into account.

Furthermore, a method is preferred in which, depending on a current operating parameter _{act of} the planetary gear, a past in the operating parameters of the planetary gear of the same type n _ref and a sensor signal _{reference feature} .DELTA.t _{xy_ref} a sensor signal characteristic .DELTA.t _{xy_calc is} precalculated and that an error is concluded, if the precalculated sensor signal characteristic Δt _{xy_calc} does not correspond to an actual sensor signal characteristic Δt _xy .

Furthermore, a method is preferred in which a rotational speed n _{act is} a current operating parameter, that a reference rotational speed n _{ref is} an operating parameter of the same type lying in the past, that Δt _{xy_ref is} a sensor signal _{reference feature} and that for a sensor signal _feature Δt _{xy_calc to be pre-calculated} :

The output signal of the sensor is calculated in advance and compared with an expected value. For example, the signal feature Δt _{12 is} compared with the predicted value Δt _{12_calc} . Based on a base signal z. B. from measurements at constant rotational speed of at least one detected planetary gear can be determined, a basic pattern can be determined. As a result, with a known operating parameters, the z. B. can be provided by an external speed sensor, a dynamic condition monitoring allows, ie all other signals can be precalculated. For example, the expected time between two signals or two signal pauses can be calculated for any speed. As a result, speed changes can be better taken into account.

• – Δt₁₂ einer Signalpause zwischen dem ersten Signal S1 und dem zweiten Signal S2,
• – Δt₂₃ einer Signalbreite des ersten Signals S1,
• – Δt₃₄ Signalpause zwischen dem zweiten Signal S2 und dem ersten Signal S1 und
• – Δt₄₁ einer Signalbreite des zweiten Signals S2 entspricht, und dass auf einen Fehler geschlossen wird,
• – wenn zumindest eines der Verhältnisse
  
  nicht einem entsprechenden Erwartungswert entspricht oder nicht konstant ist; oder
• – wenn zumindest eines der Verhältnisse
  
  nicht einem entsprechenden Erwartungswert entspricht oder nicht konstant ist; oder
• – wenn das Verhältnis
  
  ungleich dem Verhältnis
  
  ist oder nicht konstant ist; oder
• – wenn das Verhältnis
  
  ungleich dem Verhältnis
  
  ist oder nicht konstant ist.

Furthermore, a method is preferred in which the planetary gear ( 1 ) two planet wheels ( 10 . 30 ), that one revolution of the planetary gear ( 1 ) comprises first, second, third and fourth time domains Δt ₁₂ , Δt ₂₃ , Δt ₃₄ and Δt ₄₁ , wherein

• Δt ₁₂ a signal pause between the first signal S1 and the second signal S2,
• Δt _{23 of} a signal width of the first signal S1,
• - Δt ₃₄ signal pause between the second signal S2 and the first signal S1 and
• Δt ₄₁ corresponds to a signal width of the second signal S2 and that an error is concluded,
• - if at least one of the circumstances
  
  does not correspond to a corresponding expected value or is not constant; or
• - if at least one of the circumstances
  
  does not correspond to a corresponding expected value or is not constant; or
• - if the ratio
  
  unlike the relationship
  
  is or is not constant; or
• - if the ratio
  
  unlike the relationship
  
  is or is not constant.

Of each time domain .DELTA.t _{12, 23} .DELTA.t, .DELTA.t .DELTA.t ₃₄ or ₄₁ may also be a corresponding range of angles Δφ _12, Δφ _23, Δφ ₃₄ or ₄₁ be assigned to Δφ.

Due to a scanning and / or digitization of a Rohwinkelsignals as well as an exemplary digital processing in a computer unit, so-called angular errors may arise per measured pitch angle, so that in particular a method in which closed a fault is preferred if .DELTA.t ₁₂ minus .DELTA.t ₃₄ nonzero is or is not constant, or when Δt ₂₃ minus Δt _{41 is} nonzero or not constant. Thus, only two signal characteristics are used for a comparison and the difference is compared with an expected value. So a tolerance chain can be kept very low. A respective angular range Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ or Δφ _{41 can also be} assigned to the respective time range Δt ₁₂ , Δt ₂₃ , Δt ₃₄ or Δt ₄₁ .

Furthermore, a method is preferred in which the planetary gear comprises two planetary gears, so that each revolution two signals S1 and S2 are generated by means of at least one sensor and that depending on a current operating parameter n _{act of} the planetary gear, a lying in the past operating parameters of Planetary gear same type n _ref and a sensor signal _reference Δt _{xy_ref} a sensor signal characteristic .DELTA.t _{xy_calc is} precalculated and that an error is concluded when the precalculated sensor signal characteristic .DELTA.t _{xy_calc} not corresponding to a corresponding actual sensor signal characteristic .DELTA.t _xy , where .DELTA.t _{12_ref} , .DELTA.t _{23_ref} , .DELTA.t _{34_ref} , Δt _{41_ref represent} a respective sensor signal _{reference feature} , and wherein for a respective sensor signal _feature Δt _{12_calc} , Δt _{23_calc} , Δt _{34_calc} , and Δt _{41_calc to be pre-calculated} :

Furthermore, a method is preferred in which, in the absence of an expected signal on a compensating movement, in particular a rotation about a first axis of rotation, the at least one planetary gear is closed. The first axis of rotation means the own axis of rotation of the planetary gear.

Furthermore, a method is preferred in which a rotation of the at least one planetary gear is closed to a first axis of rotation when the at least one predetermined desired signal feature and the at least one actual signal feature are not identical. The first axis of rotation means the own axis of rotation of the planetary gear. Twisting to the first axis of rotation means a tilt of a planetary gear. The non-identity of the signal characteristics can, for. B. in the form of a signal frequency change.

Furthermore, a method is preferred in which the error reaction initiated a safe state and / or an error message is issued.

The invention will be explained in more detail with reference to drawings.

Show it:

1 a section of an exemplary planetary gear with two planetary gears and a sensor;

2a : an exemplary over the time t applied output signal waveform V of the inventive method in the planetary gear 1 with a n / c sensor;

2 B : the course 2a exemplified by the orbital angle φ;

2c : an exemplary over the time t applied output signal waveform V of the inventive method in the planetary gear 1 with a n / o sensor;

2d : the course 2c exemplified by the orbital angle φ;

3 : the exemplary planetary gearbox 1 in a first faulty operation in a side cross-sectional view and a plan view;

4a : an exemplary over the time t plotted output signal waveform V of the inventive method in the first faulty operation of the planetary gear 3 with a n / c sensor;

4b : the course 4a exemplified by the orbital angle φ;

4c : an exemplary over the time t plotted output signal waveform V of the inventive method in the first faulty operation of the planetary gear 1 with a n / o sensor;

4d : the course 4c exemplified by the orbital angle φ;

5 : the exemplary planetary gearbox 1 in a second faulty operation in a lateral cross-sectional view and a plan view;

6a : an exemplary over the time t plotted output signal waveform V of the inventive method in the second faulty operation of the planetary gear from 5 with a n / c sensor;

6b : the course 6a exemplified by the orbital angle φ;

6c : an exemplary over the time t plotted output signal waveform V of the inventive method in the second faulty operation of the planetary gear from 5 with a n / o sensor;

6d : the course 6c exemplified by the orbital angle φ;

7 : an exemplary reference output waveform V of the planetary gears and an exemplary reference rotational speed curve of the input shaft over the time t of the planetary gear 1 the process of the invention;

8th : an exemplary current output waveform of the planet gears and an example current speed curve of the input shaft of the planetary gear 1 the method according to the invention over time t;

9 FIG. 2: a comparison of a current faulty output signal waveform with the reference output waveform of FIG 7 at the current speed curve of 8th the process of the invention;

10 : an exemplary flowchart of a preferred embodiment of the method according to the invention and

11 : exemplary arrangement of the exemplary planetary gear from 1 for the inventive method in a car with front drive transverse.

The condition monitoring method according to the invention is based on a bevel gear differential and formed in the 1 illustrated planetary gear 1 with two planet wheels 10 . 30 a vehicle and a sensor 5 explained.

The planetary gear 1 is designed such that by means of this drive from a main drive train drive energy can be branched off to two parallel load paths and at the same time to avoid tension between the two load paths relative rotations are compensated.

For this purpose, the planetary gear has an input shaft, not shown, two connecting shafts 3 . 4 a first and second planetary carrier, not shown, with a first and second planetary gear 10 . 30 on. The two planet wheels 10 . 30 are rotatably mounted on a respective web, not shown, of the respective planet carrier.

The sensor 5 is formed and arranged such that it has an angular position of the planet gears 10 . 30 at least and / or at least one of the two axes of rotation 6 . 7 can determine, ie both a Rotation around the first axis of rotation 6 , which is at the same time its own axis of rotation, as well as a tilt, ie a rotation relative to the first axis of rotation 6 ,

For this purpose, the two planetary gears 10 . 30 in their radially outer edge region in each case a concentrically arranged marking body 20 . 40 with a break 21 respectively. 41 on. The marking body extends in the circumferential direction over an angular interval α of about 300 °. It is clear to the person skilled in the art that other angular intervals can also be selected here.

The marking body 20 . 40 can be formed in one piece or multiple parts.

The two planet wheels 10 . 30 are arranged coaxially, so that their respective first axis of rotation a common axis of rotation 6 forms and mesh each with a ring gear, each rotatably connected to one of the two connecting shafts designed as output shafts. The two planetary gears are spaced apart from the second axis of rotation and can rotate around this second axis of rotation, which perpendicularly intersects the first axis of rotation, that is, rotate. The planet wheels revolve around the second axis of rotation 7 in either direction without changing direction. In the 1 are the two planet wheels 10 . 30 represented in their respective neutral position. In this show the two output shafts 2 . 3 no relative rotation to each other.

The view of 1 also represents a snapshot, in the marking body 20 of the planetary gear 10 with a detection area 22 , which is also called "detection area", on "height" of the sensor 5 is. Between the detection area 22 and the sensor 5 is a possible distance between sensor 5 and marking body 20 minimal. The sensor 5 , which is a proximity switch, detects a presence of the detection area 22 of the marker body 20 and generates a signal representing one revolution of the planetary gear 10 represents. Clearly seen is the interruption 21 of the marker body 20 in the neutral position of the planetary gear 10 from the sensor 5 is directed away. The proximity switch 5 Switches without contact and thus without external mechanical actuating force. As a result, it has a long life and a high reliability. In the in the 1 shown sensor 5 it is a so-called n / c sensor (normally closed), ie that when detecting the presence of the marking body by means of the sensor 5 a lower output signal than when the marker body is not detected. However, it is also possible to use a "normally open" sensor (NO sensor).

2a . 2 B show an exemplary voltage output waveform V of the planet gears 10 . 30 in a direction of rotation with respect to a time t ( 2a ) and a circulation angle φ ( 2 B ) in error-free operation when using an nc sensor. The planet wheels 10 . 30 The second axis of rotation rotate continuously in one of the two directions of rotation. In one complete revolution of the transmission are by means of the sensor 5 two signals S ₁ , S ₂ generated. S ₁ represents the planetary gear 10 , S ₂ represents the planetary gear 30 , Between the two signals is a respective signal pause. Thus, a 360 ° rotation can be subdivided into four time ranges Δt ₁₂ , Δt ₂₃ , Δt ₃₄ and Δt ₄₁ and into four circumferential angular ranges or partial angles Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ and Δφ ₄₁ , the partial angle being an angle change between a falling and a rising edge (or vice versa) of the output signal of the sensor 5 is defined.

The sum of the four time ranges gives the orbital period T. The sum of the four partial angles gives the orbital angle Φ = 360 °.

In this case, the time range Δt ₁₂ corresponds to the partial angle Δφ ₁₂ , the time range Δt ₂₃ corresponds to the partial angle Δφ ₂₃ , the time range Δt ₃₄ corresponds to the partial angle Δφ ₃₄ and the time range Δt ₄₁ corresponds to the partial angle Δφ ₄₁ .

In the time ranges Δt ₂₃ , Δt ₄₁ is by means of the sensor 5 the planetary gear 10 . 30 detected, the corresponding respective output signal is low. The same applies to the partial angle Δφ ₂₃ or Δφ ₄₁ . The time ranges Δt ₂₃ , Δt ₄₁ are also referred to as signal width. In the time ranges Δt ₁₂ and Δt ₃₄ becomes the planetary gear 10 . 30 from the sensor 5 not recognized, the respective respective output signal is high (high). The same applies to the partial angles φ ₁₂ and φ ₃₄ .

In contrast to 2a . 2 B comes in 2c . 2d a n / o sensor is used, resulting in an inverse signal output waveform.

3 shows the planetary gear 1 of the 1 in a first faulty operation in a side cross-sectional view and a plan view. Unlike the in 1 shown planetary gear 1 . Here is a compensation movement of the planet gears 10 . 30 represented, ie the planet gears 10 . 30 have a turn around their own axis of rotation 6 executed. The planet wheels 10 . 30 continue to revolve around the second axis of rotation 7 in one of two directions at a constant rotational speed. The interruption 21 . 41 the marking body 20 . 40 Correspond with the twist angle around its own axis of rotation 6 such that the interruption 21 . 41 always to the sensor 5 is directed when the respective planetary gear 10 . 30 on the sensor 5 passes. This is the coverage area 22 . 42 Turned away from the sensor and signal generation is prevented.

4a to 4d show using an n / c or n / o sensor an exemplary output waveform V with respect to the time (upper image) and with respect to the orbital angle φ (bottom image) in the event that the planetary gears 10 . 30 as in 3 shown are in a balancing position. By preventing signal generation by the sensor 5 directed interruption 21 . 41 is a permanently high (n / c) sensor ( 4a . 4b ) or with a n / o sensor a permanently low output signal ( 4c . 4d ) at. The current faulty waveform V is for better comparison of the expected error-free waveform 2a . 2 B deposited in the 4a to 4d marked with V _exp . S and S _{1_exp 2_exp} represent the expected detection of the planetary gears 10 respectively. 30 , Due to the signal failure, the actual voltage _value does not coincide with the desired voltage _value twice per revolution, namely for the first time in the time domain Δt _{23_exp} and for the second time in the time domain Δt _{41_exp} .

Above the respective signal curve of the 4a to 4d the time range or angle range corresponding to the signal curve is shown with arrows.

5 shows the planetary gear 1 of the 1 in a second faulty operation in a side cross-sectional view and a plan view. Unlike the in 1 shown planetary gear 1 , is a tilt of the planetary gear 10 shown. The planet wheels 10 . 30 continue to revolve around the second axis of rotation 7 in one of two directions at a constant rotational speed. Now creates the sensor 5 a the respective circulation of the planetary gear 10 . 30 representing signal, it turns, as in 6a to 6d shown, a change in the output waveform. The tilt causes the coverage area 22 is detected earlier or later than expected depending on the direction of rotation ( 6a . 6c ), ie a time interval between the first, the planetary gear 10 representing signal S ₁ and the second, the planetary gear 30 representing signal S ₂ and a time interval between the second signal S ₂ and the first signal S ₁ are unequal. The corresponding angle sections are unequal ( 6b . 6d ).

The method according to the invention makes use of this angle information to mathematically determine the tilt by comparing ratios of partial angles to an expected value and to a "planetary gear tilted" error when the conditions are not constant and / or are not equal. Thus, the method according to the invention recognizes the "tilting error", inter alia, when the following applies:

6a . 6b show an exemplary output waveform V at said "tilt error" from 5 using an n / c sensor. 6c . 6d show an exemplary output waveform V using a n / o sensor. The current output signal waveform V is the output signal waveform V out 2a . 2 B respectively. 2c . 2d deposited, which here corresponds to the expected output _waveform V _exp .

Shown is a tilt error of the planetary gear 30 whose detection is represented by the signal S ₂ . It can be clearly seen that the current signal S _{2 is} generated approximately 45 ° to "early" than the expected signal S _{2_exp} would have been generated. The signal S ₁ , which is the detection of the planetary gear 10 represents, is and remains identical to the expected signal S _{1_exp} .

Above the respective signal curve of the 6a to 6d are the respective current time ranges .DELTA.t ₁₂ , .DELTA.t ₂₃ , .DELTA.t ₃₄ and .DELTA.t ₄₁ the expected time _ranges .DELTA.t _{12_exp} , .DELTA.t _{23_exp} , .DELTA.t _{34_exp} and .DELTA.t _{41_exp} opposed and shown with arrows. The respective time ranges correspond to respective angular ranges Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ and Δφ ₄₁ or Δφ _{12_exp} , Δφ _{23_exp} , Δφ _{34_exp} and Δφ _{41_exp} .

Another way to determine the tilt error is in the 7 to 9 described. In this case, output signals of the sensor 5 precalculated and compared with actual values, whereby angle or time values can be compared with each other.

The reference value is a time range and is determined by, at constant speed, n revolutions of the planet gears 10 . 30 be measured. In the 7 to 9 is the speed n of the input shaft with "Input Speed GRA" and plotted over the time t. A reference pattern is generated which is in 7 is _exemplified and includes a reference _speed n _ref and reference time _{ranges At 12_ref} , _{At 23_ref} , _{At 34_ref} and _{At 41_ref} .

kann nun für eine beliebige Drehzahl n_act, wie in 8 dargestellt, der erwartete Zeitbereich Δt_{xy_calc} vorausberechnet werden. So wird mit

der Zeitbereich Δt_{12_calc}, der gleich dem Zeitbereich Δt_{34_calc} ist, und mit

der Zeitbereich Δt_{23_calc} der gleich dem Zeitbereich Δt_{41_calc} ist, vorausberechnet. Stimmt die vorausberechnete Zeit nicht mit dem entsprechenden Ist-Wert überein, wenn also Δt_{12_calc} ungleich Δt₁₂, Δt_{23_calc} ungleich Δt₂₃, Δt_{34_calc} ungleich Δt₃₄ oder Δt_{41_calc} ungleich Δt₄₁ ist, so wird auf den Fehler „Planetenrad verkippt” erkannt.By means of the mathematical relationship

can now, for any speed n _act, as in 8th represented, the expected time range .DELTA.t _{xy_calc be} pre-calculated. So will with

the time domain Δt _{12_calc} , which is equal to the time domain Δt _{34_calc} , and with

the time domain Δt _{23_calc} which is equal to the time domain Δt _{41_calc} has been precalculated. If the predicted time does not coincide with the corresponding actual value, ie if Δt _{12_calc is} not equal to Δt ₁₂ , Δt _{23_calc} not equal to Δt ₂₃ , Δt _{34_calc} not equal to Δt ₃₄ or Δt _{41_calc} not equal to Δt ₄₁ , then the error "planetary gear tilted" is detected ,

In 9 is the comparison of the respective expected signals, with the corresponding signal characteristics .DELTA.t _{12_calc} , .DELTA.t _{23_calc} , .DELTA.t _{34_calc} , .DELTA.t _{41_calc} , with the current erroneous output signal _waveform based on the tilting, with the signal characteristics .DELTA.t ₁₂ , .DELTA.t ₂₃ , .DELTA.t ₃₄ and .DELTA.t ₄₁ shown.

In the 10 are exemplary of the individual steps of a preferred embodiment of the method according to the invention. In a starting point 100 begins a revolution of the planetary gear 10 . 30 , In a first step 110 is done by means of the sensor 5 generates a signal. In a subsequent step 130 an actual signal feature of the signal is compared with a desired signal feature. If the characteristics match, there is no error. If the actual feature and the target feature do not match, an error is detected and output 140 , There will be an end 200 of the circulation and the steps are repeated.

This in 10 The flow chart shown is only an example of further inventive method in which, for example, can be provided that automatically a safe state is initiated and not as in 10 shown, only one output 140 the error occurs.

11 shows an exemplary arrangement of the planetary gear according to the invention 1 in a car with front drive transversely. The sensor 5 is arranged in the direction of travel right above an output shaft.

The illustrated figures are only exemplary embodiment of the invention. It is understood that any other embodiment is conceivable without departing from the scope of this invention.

LIST OF REFERENCE NUMBERS

1

Planetary gear, bevel gear differential

3, 4

Connecting shaft, output shaft

5

sensor

6

first, own axis of rotation

7

second axis of rotation

10

first planetary gear

20

marking body

21

interruption

22

detection range

30

second planetary gear

40

marking body

41

interruption

42

detection range

n

Speed (Input Speed GRA)

n _act

current speed

n _ref

Reference speed

S ₁

Signal planetary gear 10

S ₂

Signal planetary gear 30

S _{1_exp}

expected signal planetary gear 10

S _{2_exp}

expected signal planetary gear 30

t

Time

T

Time span for 360 ° circulation

U

Voltage in volts

V

waveform

V _ref

Reference signal output waveform

V _exp

expected signal output curve

V _calc

precalculated signal output curve

.delta.t

time range

Δt ₁₂

Signal break between planetary gear 10 and 30

Δt ₂₃

Signal width planetary gear 10

Δt ₃₄

Signal break between planetary gear 30 and 10

Δt ₄₁

Signal width planetary gear 30

Δt _{xy_calc}

expected time domain with x, y = 1, ..., 4

Δt _{12_calc}

precalculated signal pause between planetary gear 10 and 30

Δt _{23_calc}

precalculated signal width planetary gear 10

Δt _{34_calc}

precalculated signal pause between planetary gear 30 and 10

Δt _{41_calc}

precalculated signal width planetary gear 30

Δt _{12_exp}

expected signal break between planetary gear 10 and 30

Δt _{23_exp}

expected signal width planetary gear 10

Δt _{34_exp}

expected signal break between planetary gear 30 and 10

Δt _{41_exp}

expected signal width planetary gear 30

φ

angle

Φ

360 ° -Umlaufwinkel

Δφ

Orbital angle range, partial angle

Δφ ₁₂

Partial angle between planetary gear 10 and 30

Δφ ₂₃

part angle

Δφ ₃₄

Partial angle between planetary gear 30 and 10

Δφ ₄₁

part angle

Δφ _{12_exp}

expected partial angle between planetary gear 10 and 30

Δφ _{23_exp}

expected partial angle

Δφ _{34_exp}

expected partial angle between planetary gear 30 and 10

Δφ _{41_exp}

expected partial angle

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 2007197338 A1 [0012]
• JP 2007154939 A2 [0012]
• EP 0939247 A2 [0012]

Cited non-patent literature

• "Conventional Powertrain and Hybrid Drives" (Ed. Konrad Reif, Vieweg + Teubner Verlag, 2010, pp. 150ff.) [0011]

Claims (18)

Method for condition monitoring of at least one planetary gear ( 10 . 30 ) of a planetary gear ( 1 ), wherein the at least one planetary gear ( 10 . 30 ) in the planetary gear ( 1 ) is rotatably mounted, characterized in that - in a forward rotation of the at least one planetary gear ( 10 . 30 ) on at least one sensor ( 5 ) by means of the at least one sensor ( 5 ) at least one signal (S ₁ , S ₂ ) is generated, - at least one actual signal feature of the at least one generated signal (S ₁ , S ₂ ) is compared with at least one predetermined nominal signal feature each time, and - an error is concluded, if the at least one predetermined nominal signal feature and the at least one respective actual signal feature of the at least one generated signal (S ₁ , S ₂ ) are not identical. A method according to claim 1, characterized in that in addition a first and second circumferential direction of the at least one planetary gear ( 10 . 30 ) is detected. Method according to claim 1 or 2, characterized in that the at least one planetary gear ( 10 . 30 ) a marking body ( 20 . 40 ) which extends in the circumferential direction over an angular range and at least one interruption ( 21 . 41 ) and that upon detection of the at least one interruption ( 21 . 41 ) by means of the at least one sensor 5 a signal generation is prevented. Method according to one of the preceding claims, characterized in that an amplitude of the at least one signal (S ₁ , S ₂ ) is a predetermined signal feature. Method according to one of the preceding claims, characterized in that a signal width (Δt ₂₃ , Δt ₄₁ ) of the at least one signal (S ₁ , S ₂ ) is a predetermined signal feature. Method according to one of the preceding claims, characterized in that a width of a signal pause (Δt ₃₄ , Δt ₁₂ ) is a predetermined signal feature. Method according to one of the preceding claims, characterized in that an error is concluded when a ratio of at least one signal width (Δt ₂₃ , Δt ₄₁ ) and at least one width of a signal pause (Δt ₃₄ , Δt ₁₂ ) does not correspond to a predetermined expected value. Method according to one of the preceding claims, characterized in that an error is concluded when a first ratio of at least one first signal width (Δt ₂₃ , Δt ₄₁ ) and at least one first width of a first signal pause (Δt ₃₄ , Δt ₁₂ ) does not correspond to one second ratio of at least a second signal width (At ₂₃ , At ₄₁ ) and at least a second width of a second pulse pause (At ₃₄ , At ₁₂ ). Method according to one of the preceding claims, characterized in that in dependence on - a current operating parameter (n _act ) of the planetary gear ( 1 ), - a past in the past operating parameters of the planetary gear ( 1 ) Of the same type (n _ref), and - a sensor signal reference feature .DELTA.t _{xy_ref} a sensor signal feature .DELTA.t _{xy_calc} is calculated in advance and that is closed on a fault, if the predicted sensor signal feature .DELTA.t _{xy_calc} does not correspond to an actual sensor signal feature .DELTA.t _xy. A method according to claim 9, characterized in that a rotational speed n _{act is} a current operating parameter, that a reference rotational speed n _{ref is} a past operating parameter of the same type, that Δt _{xy_ref is} a sensor signal _{reference feature} , and that for a predictive sensor signal feature

Method according to one of the preceding claims, characterized in that the planetary gear ( 1 ) two planet wheels ( 10 . 30 ), that one revolution of the planetary gear ( 1 ) comprises a first, second, third and fourth time domain Δt ₁₂ , Δt ₂₃ , Δt ₃₄ and Δt ₄₁ , wherein Δt ₁₂ a signal pause between the first signal S1 and the second signal S2, .DELTA.t ₂₃ a signal width of the first signal S1, .DELTA.t _34th Signal pause between the second signal S2 and the first signal S1 and .DELTA.t ₄₁ corresponds to a signal width of the second signal S2, and that an error is concluded - if at least one of the ratios

does not correspond to a corresponding expected value or is not constant; or - if at least one of the ratios

does not correspond to a corresponding expected value or is not constant; or - if the ratio

unlike the relationship

is or is not constant; or - if the ratio

unlike the relationship

is or is not constant. A method according to claim 11, characterized in that an error is concluded, - when Δt ₁₂ -Δt _{34 is} not equal to zero or is not constant; or - if Δt ₂₃ -Δt _{41 is} nonzero or not constant. Method according to one of claims 1 to 10, characterized in that the planetary gear ( 1 ) two planet wheels ( 10 . 30 ), that one revolution of the planetary gear ( 1 ) comprises a first, second, third and fourth partial angle Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ and Δφ ₄₁ , wherein Δφ ₁₂ with a signal pause Δt ₁₂ between the first signal S1 and the second signal S2, Δφ ₂₃ with a signal width Δt ₂₃ of first signal S1, Δφ ₃₄ corresponds to a signal pause Δt ₃₄ between the second signal S2 and the first signal S1 and Δφ ₄₁ corresponds to a signal width Δt _{41 of} the second signal S2, and that an error is concluded - if at least one of the ratios

does not correspond to a corresponding expected value or is not constant; or - if at least one of the ratios

does not correspond to a corresponding expected value or is not constant; or - if the ratio

unlike the relationship

is or is not constant; or - if the ratio

unlike the relationship

is or is not constant. A method according to claim 13, characterized in that an error is concluded, - when Δφ ₁₂ -Δφ _{34 is} not equal to zero or is not constant; or - if Δφ ₂₃ -Δφt _{41 is} nonzero or not constant. Method according to claim 9 or 10, characterized in that the planetary gear ( 1 ) two planet wheels ( 10 . 30 ), so that each circulation two signals S1 and S2 by means of the at least one sensor 5 be generated and that in dependence on - a current operating parameter (n _act ) of the planetary gear ( 1 ), - a past in the past operating parameters of the planetary gear ( 1 ) Of the same type (n _ref), and - a sensor signal reference feature .DELTA.t _{xy_ref} a sensor signal feature .DELTA.t is predicted _{xy_calc} and that is closed on a fault, if the predicted sensor signal feature .DELTA.t _{xy_calc} not a corresponding actual sensor signal feature .DELTA.t _xy corresponds, wherein .DELTA.t _{12_ref,} .DELTA.t _{23_ref,} Δt _{34_ref} , Δt _{41_ref represent} a respective sensor signal _{reference feature} , and wherein for a respective sensor signal _feature Δt _{12_calc} , Δt _{23_calc} , Δt _{34_calc} and Δt _{41_calc to be pre-calculated} :

Method according to one of the preceding claims, characterized in that in the absence of an expected signal (S ₁ ', S ₂ ') to a compensating movement, in particular to a rotation about a first axis of rotation ( 6 ), of the at least one planetary gear ( 10 . 30 ) is closed. Method according to one of the preceding claims, characterized in that when the at least one predetermined desired signal feature and the at least one actual signal feature are not identical, to a rotation of the at least one planetary gear ( 10 . 30 ) to a first axis of rotation ( 6 ) is closed. Method according to one of the preceding claims, characterized in that initiated as a fault reaction, a safe state and / or an error message is issued.

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