DE102015209866A1 - 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) on at least two sensors (5, 8) by means of each of the at least two sensors (5, 8) at least one signal is generated, at least one actual signal feature of the at least one generated signal with at least one predetermined Target signal characteristic is compared, and is closed to an error when the at least one predetermined setpoint signal feature and the at least one actual signal feature of the at least one generated signal 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 be additionally 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 redundant condition monitoring of one or more planetary gears in a planetary gear is desirable, for. B. to detect malpositions of one or more planet gears. 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 2-wire differential Hall effect IC and is connected to a voltage source for operation. The transmission speed sensor may detect the rotational speed signal from ferromagnetic gears, stamping plates or applied multipoles, taking advantage of the Hall effect and providing a signal having a constant amplitude independent of the rotational speed. For signal output, the supply current is in Rhythm of the incremental signal modulated. 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 according to the preamble of claim 1.

This object is achieved according to the invention by generating at least one signal by at least one of the two axes of rotation when the at least one planetary gear is rotated past at least one actual signal characteristic of the at least one generated signal having at least one predetermined nominal value. Signal characteristic is compared, and is closed to an error when the at least one predetermined setpoint signal feature and the at least one actual signal feature of the at least one generated signal 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 plurality of sensors, then depending on a number of sensors, a respective signal can be generated which represents a respective actual signal of the at least one planetary gear.

With the method according to the invention a detection of a malposition of the at least one planetary gear is reliably possible. 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 about its own axis of rotation can lead to problems, in particular malfunctions due to e.g. of fractures in the planet carrier or breaks in the load paths of the transmission, lead, which can be detected early with the method according to the invention. 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.

For two sensors z. B. per complete revolution of the at least one planetary gear, a signal per sensor, so two signals in total, are generated, which represent a rotation of the at least one planetary gear about the second axis of rotation. In an exemplary planetary gear with two planetary gears and two sensors "z. B. each sensor per revolution two planetary gears.

In order to safely conclude an error, the direction of rotation about the second axis of rotation of the detected planetary gear must be taken into account. The direction of rotation about the second axis of rotation can be determined on the basis of angle information. For example, in a planetary gearing, when a planetary gear rotates about the second axis of rotation, a first angle follows a second angle, the second angle being e.g. 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, a determination is to be made as to whether a difference of the first and second angles with a positive sign circulates in a first direction, e.g. left-handed, from two directions of rotation and with a negative sign in a second direction, e.g. 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.

For the condition monitoring is irrelevant in which of the two directions, the at least one planet rotates the second axis of rotation, as long as the direction of rotation does not change between edges of a revolution.

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

In particular, it has been found that a further advantage of this method lies in the fact that a sensor structure can be made divers to one another. That means different Hardware components can be used with the two sensors. This increases the safety against accidental electrical errors, because in particular common errors can be excluded.

In addition, a method is preferred in which an error is concluded when a difference from the at least one predetermined nominal signal characteristic and from the at least one actual signal characteristic of the at least one generated signal respectively reaches or exceeds a predetermined limit value.

In addition, a method is preferred 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 detecting this at least one interruption of the marking body of the at least one planetary gear.

By means of the marking body a better detection of the planetary gear is possible in a structurally simple way, if this passes by the sensor. The marking body is rotatably connected to the planetary gear, so that conclusions can be drawn from the detection of the marking body on the movement of the planetary gear. The compound can e.g. an adhesive bond or screw, but other compounds for the expert are conceivable.

In particular, an interruption of the marking body can be detected in an advantageous manner. The interruption can z. B. may be a recess or gap, which can be directed with a rotation of the at least one planetary gear about the first axis of rotation to the sensor. This rotation about the first axis of rotation can, for. B. caused by a compensating movement to compensate for tension of the two output axles.

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 pulse width of the at least one signal is a predetermined signal feature.

In addition, a method is preferred in which a width of a signal pause is a predetermined signal feature.

Particularly preferred is a method in which a time interval Δt ₅₈ or angle-dependent distance Δφ ₅₈ between generated signals is a predetermined signal feature.

Also particularly preferred is a method in which a time interval Δt ₅₈ or angle-dependent distance Δφ ₅₈ between a first signal generated by a first sensor and a second signal generated by a second sensor is a predetermined signal feature, both the first and the second signal the same at least one planetary gear ( 10 . 30 ).

Furthermore, a method is preferred in which the sensors are n / c sensors. For an n / c sensor, the circuit of the sensor is closed by default, d. H. if the sensor does not detect a planetary gear or marker body, the sensor provides a high voltage value, e.g. B. the voltage value "high".

The advantage of the n / c sensor is that a disconnection of the supply voltage is better detected when the planetary gear is stationary. This is especially true if during normal operation over a larger angular range is not detected and accordingly the voltage value "high" would be expected over a larger area.

In addition, a method is preferred in which the sensors are n / o sensors. For a n / o sensor, the circuit of the sensor is open by default, i. H. if no planetary gear is in front of the sensor, the sensor supplies the voltage value "low".

The advantage of the n / o sensor is that it mainly supplies a low voltage value and thus is more energy-efficient than an n / c sensor. This applies in particular when the angular ranges at which the sensor is not detected are larger than the angular ranges at which the sensor detects.

In addition, a method is preferred which involves two sensors, one of the two sensors being an n / c sensor and another of the two sensors being an n / o sensor.

A disadvantage of an n / o sensor is that u.U. not between a defect of the sensor itself, z. B. the termination of a power supply and a mechanical defect in the transmission could be distinguished.

A disadvantage of an n / c sensor is that it predominantly provides a "high" signal and thus consumes a lot of energy.

It has been found that by means of a combination of an n / o sensor and an n / c sensor advantageously a redundant and complementary output signal of the sensors can be generated, so that the advantages of both types of sensors can be connected to each other.

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 two sensors;

2a FIG. 2: shows an exemplary output signal curve V of the method according to the invention applied over time t in a first preferred embodiment with two n / c sensors; FIG.

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

3a : an exemplary output waveform V plotted over time t of the method according to the invention in a further preferred embodiment with two n / o sensors;

3b : the course 3a exemplified by the orbital angle φ;

4a : an exemplary output waveform V plotted over time t of the method according to the invention in a further preferred embodiment with an n / c and a n / o sensor;

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

5 : an exemplary flowchart of the preferred embodiment of 4a ,

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 first sensor 5 and a second sensor 8th 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 two sensors 5 . 8th are arranged axially parallel and can be an angular position of the planetary gears 10 . 30 at least and / or at least one of the two axes of rotation 6 . 7 determine, ie both a rotation about 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 another angular interval can also be selected here.

The marking body 20 . 40 can be formed in one or more parts and is rotatably connected to the planetary gear, so from the detection of the marking body 20 . 40 on the movement of the planetary gear 10 . 30 can be concluded.

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 planet wheels 10 . 30 are to the second axis of rotation 7 spaced and can around this second axis of rotation 7 that the first axis of rotation 6 perpendicularly cuts, rotates, ie revolves. The planet wheels 10 . 30 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 which the marker body 20 of the planetary gear 10 with a first detection area 22 and a second detection area 23 , which is also called "detection area", on "height" of the sensors 5 . 8th is. Clearly seen is the interruption 21 of the marker body 20 in the neutral position of the planetary gear 10 from the sensor 5 . 8th is directed away. Between the detection area 22 and the sensor 5 and between the detection area 23 and the sensor 8th a possible distance is minimal. The sensor 5 detects a presence of the detection area 22 of the marker body 20 and generates a first signal before the planetary gear 10 around the second axis of rotation 7 continues to run and the sensor 8th a presence of the coverage area 23 detected and generates a second signal. Between the first signal of the first sensor 5 and the second signal of the second sensor 8th is a time interval .DELTA.t _58, corresponding to a circumferential or angle-dependent distance Δφ _58th In other words, there is a phase shift of the two signals. At a constant input speed, this distance is also constant.

At a rotation of the planetary gears 10 . 30 around its own axis of rotation 6 will, since the interruption 21 . 41 to both sensors 5 . 8th executed, a signal generation of the sensors 5 . 8th prevented and detected regardless of the input speed to an error.

At a constant input speed and in the presence of a tilt of one of the planet gears 10 . 30 the time interval Δt ₅₈ between the two signals changes, ie it becomes larger or smaller, so that the error "tilting" is detected.

The proximity switches 5 . 8th Switch without contact and thus without external mechanical actuation force. As a result, they have a long life and a high reliability.

• – 0° < 40° Erfassung des Planetenrads 10
• – 41° < 179° keine Erfassung eines Planetenrads
• – 180° < 220° Erfassung des Planetenrads 30
• – 221° < 359° keine Erfassung eines Planetenrads,

wobei diese vier Bereiche einem jeweiligen Teilwinkel ∆φ entsprechen, nämlich ∆φ₁₂, ∆φ₂₃, ∆φ₃₄ und ∆φ₄₁ Den Teilwinkeln ∆φ₁₂, ∆φ₂₃, ∆φ₃₄ und ∆φ₄₁ ist ein jeweiliger entsprechender Zeitbereich ∆t₁₂, ∆t₂₃, ∆t₃₄ und ∆t₄₁ zugeordnet. Dabei entspricht ∆φ₂₃ und ∆φ₄₁ der Erfassung des Planetenrads 10 bzw. 30 während ∆φ₁₂ und ∆φ₃₄ der Nicht-Erfassung des jeweiligen Planetenrads 10, 30 entspricht. Diese Notation gilt sowohl für den Sensor 5 als auch für den Sensor 8. How further the 1 and in the course of the 2a to 4b can be shown, the circulation of a respective planetary gear 10 . 30 into recirculating angular ranges of detection and non-detection. The circulation angle ranges can have the following values:

• - 0 ° <40 ° detection of the planetary gear 10
• - 41 ° <179 ° no detection of a planetary gear
• - 180 ° <220 ° detection of the planetary gear 30
• - 221 ° <359 ° no detection of a planetary gear,

these four regions corresponding to a respective partial angle Δφ, namely Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ and Δφ ₄₁ The partial angles Δφ ₁₂ , Δφ ₂₃ , Δφ ₃₄ and Δφ ₄₁ is a respective corresponding time range Δ t ₁₂ , Δt ₂₃ , Δt ₃₄ and Δt ₄₁ assigned. In this case, Δφ corresponds to ₂₃ and Δφ _{41 of} the detection of the planetary gear 10 respectively. 30 while Δφ ₁₂ and Δφ _34, the non-detection of the respective planetary gear 10 . 30 equivalent. This notation applies to both the sensor 5 as well as for the sensor 8th ,

The partial angle can thus be defined as an angle change between a falling and a rising or a rising edge and a falling edge of an output signal of the sensor or - in other words - as an angle change between a detection of the at least one planetary gear and a signal pause, which follows a detection and vice versa ,

2a . 2 B show an exemplary voltage output waveform V of the two planetary gears 10 . 30 in relation to a time t ( 2a ) and a circulation angle φ ( 2 B ) in error-free operation when using two n / c sensors 5 . 8th , In the respective upper illustration is the means of the first sensor 5 generated course, in the respective lower representation is the means of the second sensor 8th generated course shown.

Captures one of the sensors 5 . 8th one of the two planet gears 10 . 30 a signal is generated and there is a low voltage value (Low). Will not be the two planet gears 10 . 30 detected, there is a high voltage value (High).

This results in a characteristic output signal course of the two sensors over the time t or over the angle φ of the input shaft 5 . 8th , The planetary gear 10 . 30 representing signals of the sensors 5 . 8th are offset in terms of time or angle by a distance Δt ₅₈ or Δφ ₅₈ , ie phase-shifted. At a constant input speed results in a constant phase shift between the two signals by an amount .DELTA.t _58th

If this amount changes at constant speed, it can be concluded that there is an electrical fault.

3a . 3b show an exemplary voltage output waveform V of the two planetary gears 10 . 30 in relation to a time t ( 3a ) and a circulation angle φ ( 3b ) in error-free operation. Unlike the in 2a . 2 B Course shown are both sensors 5 . 8th n / o sensors, ie, detects one of the sensors 5 . 8th one of the two planet gears 10 . 30 a signal is generated and there is a high voltage value (High). Will not be the two planet gears 10 . 30 detected, there is a low voltage value (Low). Incidentally, the comments on 2a . 2 B to get expelled.

4a . 4b show an exemplary voltage output waveform V of the two planetary gears 10 . 30 in relation to a time t ( 4a ) and a circulation angle φ ( 4b ) in error-free operation when using n / c sensors 5 and one n / o sensors 8th , In the respective upper illustration, that is by means of the first n / c sensor 5 generated curve, in the respective lower representation is the means of the second n / o sensor 8th generated course shown.

At the in 4a . 4b The advantages of an n / c sensor, that is to say a predominantly low voltage value, thus saving energy, and a n / o sensor in which a disconnection of the supply voltage is better detected when the planetary gear is stationary are combined, it being immaterial which of the two sensors 5 . 8th an n / c sensor and which is a n / o sensor. Incidentally, the comments on 2a . 2 B to get expelled.

In the 5 are exemplary of the individual steps of a preferred embodiment of the method according to the invention, in which a time interval Δt ₅₈ between a first means of the sensor 5 generated signal and a second means of the sensor 8th generated signal is a predetermined signal feature shown. In a starting point 100 At time t _0, one revolution of the planetary gear starts 10 . 30 , In a first step 110 at a time t ₁ is by means of the sensor 5 generates the first signal. In a subsequent step 120 at time t ₂ is by means of the sensor 8th generates the second signal. In the subsequent step 130 At a time t _3, the time interval Δt ₅₈ , ie the phase shift between the first and the second signal, is compared with a desired time value. If the times coincide, then there is no mistake. If the phase shift and the setpoint time value 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 5 The flow chart shown is an example of further inventive method in which, for example, it may be provided that the transmission system automatically shuts off upon detection of an error and not as in 5 shown, only one output 140 the error occurs.

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

first sensor

6

first, own axis of rotation

7

second axis of rotation

8th

second sensor

10

first planetary gear

20

marking body

21

interruption

22

detection range

30

second planetary gear

40

marking body

41

interruption

42

detection range

100

Start circulation

110

first step, signal generation first signal by means of sensor 5

120

second step, signal generation second signal by means of sensor 8th

130

third step, comparison Δt ₅₈ with setpoint

140

fourth step, error output

200

End of circulation

Δt, Δt ₁ -Δt ₄

time range

Δt ₅₈

Phase shift, time interval

Δφ, Δφ ₁ -Δφ ₄

 Orbital angle range, partial angle

Δφ ₅₈

angle-dependent distance

t ₀ -t ₃

timings

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 (11)

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 ) to at least two sensors ( 5 . 8th ) by means of each of the at least two sensors ( 5 . 8th ) at least one signal is generated, - at least one actual signal feature of the at least one generated signal is compared with at least one predetermined nominal signal feature, and - is concluded on an error, if the at least one predetermined target signal feature and the at least in each case an actual signal feature of the at least one generated signal is not identical. Method according to Claim 1, characterized in that an error is concluded when a difference from the at least one predetermined nominal signal characteristic and from the at least one respective actual signal feature of the at least one generated signal respectively reaches or exceeds a predetermined limit value. 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 this at least one interruption ( 21 . 41 ) of the marking body ( 20 . 40 ) of the at least one planetary gear ( 10 . 30 ) signal generation is prevented. Method according to one of the preceding claims, characterized in that an amplitude of the at least one signal is a predetermined signal feature. Method according to one of the preceding claims, characterized in that a pulse width of the at least one signal is a predetermined signal feature. Method according to one of the preceding claims, characterized in that a width of a signal pause, a predetermined signal feature. Method according to one of the preceding claims, characterized in that a time interval Δt ₅₈ or angle-dependent distance Δφ ₁₂ between generated signals is a predetermined signal feature. Method according to one of the preceding claims, characterized in that a time interval Δt ₅₈ or angle-dependent distance Δφ ₁₂ between a first signal generated by a first sensor and a second signal generated by a second sensor is a predetermined signal feature, wherein both the first as well as the second signal the same at least one planetary gear ( 10 . 30 ). Method according to one of the preceding claims, characterized in that the sensors are n / c sensors. Method according to one of the preceding claims, characterized in that the sensors are n / o sensors. Method according to one of the preceding claims, characterized in that it involves two sensors, one of both sensors being an n / c sensor and another of the two sensors being an n / o sensor.

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