Belt Drive Sensor Assembly

Abstract

The belt drive comprises a first pulley having a first diameter, a second pulley having a second diameter, and a belt arranged in each case on the sides of the first and second pulleys and configured to transmit a rotational movement of the first pulley to the second pulley. The belt drive further comprises a first sensor assembly arranged and configured to detect a rotational position of the first pulley and a second sensor assembly arranged and configured to detect a rotational position of the second pulley. The first diameter corresponds to a first integer multiple of a unit length and the second diameter corresponds to a second integer multiple of the same unit length, the first and second integer multiples of the unit length being mutually prime.

Description

[Technical field]

[0001] A sensor assembly for a belt drive and method for measuring the rotational position of a pulley is described herein. [Background technology]

[0002] As electric drives for steering of motor vehicles, for example, power steering systems (electric power steering: EPS) are known. In the case of axial parallel drives (APA), a so-called "power pack" consisting of a motor section and a control or regulating system in the form of an electronic data processing unit / section (ECU) can be connected via a belt drive to a ball screw drive (KGT), which converts the rotational movement of the motor section into a translational movement to change the toe angle of the wheels of the vehicle.

[0003] A belt drive, which combines a "power pack" or motor section with a ball screw drive, typically has two pulleys and one belt. In order to improve known power steering systems as well as to implement a fully electrically assisted steering system (Steer-by-Wire: SBW) for automobiles, it is necessary to measure the current or actual toe angle of the wheels as changed by the steering wheel in order to correctly execute the steering operation of the automobile initiated by the automobile driver.

[0004] In principle, inductive, capacitive, magnetic and / or optical sensors can be used to measure the rotational position of the pulley of the belt drive that connects the power pack or motor section to the ball screw drive, and thus a determination can be made about the current toe angle of the wheels as changed by steering. In practice, however, optical sensors are uncommon due to contamination of the sensors and pulleys and / or lack of precision. The most accurate measurement results can be obtained by using inductive sensors. Summary of the Invention [Problem to be solved by the invention]

[0005] However, one problem with detecting the current or actual rotational positions of the pulleys is that the specific rotational positions of the two pulleys of the belt drive do not necessarily correspond clearly to the specific toe angle of the vehicle as changed by steering. Therefore, by measuring the rotational positions of the pulleys, the actual or current toe angle of the wheels as changed by steering can be determined only if the detection of the rotational positions of the pulleys is complemented by direct sensor detection on the wheels, or at least by an evaluation of the detection history of the rotational positions of the pulleys.

[0006] On the other hand, the former involves additional technical effort and therefore overshadows the advantages of detecting the rotational position of the pulley for adjusting or controlling the steering. The latter assumes that the history is always available, i.e. also when the vehicle starts to move, and that the memory always outputs past data at the same time as the sensor records. If the records of past detections of the rotational positions are not available, for example when the vehicle starts to move, it is not possible to reliably determine the current toe angle of the wheel moved by the steering based only on the rotational position of the pulley. Therefore, a safe control of the vehicle is not possible in this situation. Furthermore, for example a tire change can lead to an interruption and / or misuse of the recorded detection records, so that a reliable measurement of the actual steering angle based on the recorded rotational positions of the pulleys of the steering system is not possible.

[0007] The technical problem is therefore to provide an improved belt drive for a motor vehicle steering system having a sensor system capable of measuring the rotational position of the pulleys of the belt drive over the entire adjustment range of the steering system and unambiguously assigning it to a particular current toe angle of the wheels of the motor vehicle moved by the steering system, and concomitantly providing a method for measuring the rotational position of the pulleys of the belt drive over the entire adjustment range of the steering system and unambiguously assigning it to a particular current toe angle of the wheels of the motor vehicle moved by the steering system. [Means for solving the problem]

[0008] These problems are solved by a device according to claim 1 and a method according to the independent claims. Preferred implementation schemes are defined by the further claims.

[0009] The belt drive includes at least a first pulley having a first diameter and a second pulley having a second diameter, and further includes a belt disposed on each side of the first and second pulleys and configured to transfer rotational motion of the first pulley to the second pulley.

[0010] A first sensor assembly is positioned and configured to detect the rotational position of the first pulley, and a second sensor assembly is positioned and configured to detect the rotational position of the second pulley.

[0011] The first diameter corresponds to a first integer multiple of a unit length. The unit length may be, for example, millimeters, centimeters, inches, or any other unit of length. That is, the first pulley has a diameter of a length or size that can be expressed as a product of a whole number and a selected unit length, for example, centimeters, inches, or any other unit of length. As an example, the first pulley may have a diameter of 31 unit lengths, for example, 31 millimeters.

[0012] The second diameter corresponds to a second integer multiple of the same unit length, for example, the second pulley may have a diameter of 97 unit lengths, e.g., 97 millimeters.

[0013] The first and second integer multiples of the unit length are different from each other and are relatively prime to each other. For example, 31 and 97 are different natural numbers and relatively prime to each other. That is, they have no common natural divisor other than 1.

[0014] In other words, the size ratio between the first pulley and the second pulley and / or the length ratio between the first diameter and the second diameter corresponds to the ratio of two different natural numbers, and the two different natural numbers have no common natural divisor other than 1.

[0015] If desired, the first and / or second integer multiple may correspond to a prime number or a product of the first and / or second unit length and a prime number, i.e. the diameter of the first and / or second pulley may correspond to a unit length of any length and a product of a natural number, in particular a prime number, respectively, so that the first and second integer multiples of the unit length never have a common natural factor.

[0016] The first sensor assembly may comprise a non-contact position sensor, in particular a non-contact inductive position sensor. Furthermore, the second sensor assembly may also comprise a non-contact position sensor, in particular a non-contact inductive position sensor. For example, the first and / or second sensor assembly may comprise a CIPOS® sensor for determining the rotational position of the first and / or second pulley.

[0017] Alternatively or additionally, the first sensor assembly and / or the second sensor assembly may comprise capacitive, magnetic and / or optical sensors.

[0018] The first and / or second sensor assemblies may each be arranged to measure the rotational position or rotational position of the pulley, i.e. the first and / or second sensor assemblies may each measure how many degrees the pulley has rotated relative to a defined or notional zero or starting position.

[0019] In one variant, the first and / or second sensor assemblies can measure the rotational position of the first and / or second pulleys to an accuracy of, for example, 1.2 degrees, whereby this measurement accuracy already includes deviations from technically ideal pulley rotations associated with the mechanics of real belt drives.

[0020] In one embodiment, at least a portion of the first sensor assembly can be incorporated into and / or coupled to the first pulley, and at least a portion of the second sensor assembly can be incorporated into and / or coupled to the second pulley, for example, the conductor loop and / or the magnetic element can be formed as part of, coupled to, or connected to the pulley.

[0021] Furthermore, the belt drive can be equipped with or can be associated and / or connected to a data processing device. The data processing device can in particular be an electronic data processing device. In one variant, the data processing device can be entirely or partly formed by and / or part of the first and / or second sensor assembly or integrated therein. The data processing device can evaluate and store data acquired by the first and / or second sensor assembly and / or make the acquired data and / or its evaluation accessible to an external technical device, for example an on-board computer. As a further development, the data processing device can be integrated into or designed as part of the on-board computer.

[0022] The data processing device can be configured to specifically determine a rotational or set position of the belt drive along a set path of the belt drive consisting of multiple complete revolutions of the first and / or second pulleys based on detection of the first sensor assembly and detection of the second sensor assembly.

[0023] This is made possible by the different diametric size or length ratio of the first and second pulleys, respectively, which refers to the circumference of the pulley and the transmission ratio of a belt drive having two pulleys.

[0024] For example, if the first pulley has a diameter of 31 unit lengths and the second pulley has a diameter of 97 unit lengths, then the transmission ratio for the belt drive from the first small pulley to the second large pulley is 97 / 31, or approximately 3.129. That is, approximately 3.129 revolutions of the first small pulley make one complete revolution of the second large pulley. The reciprocal of this is the transmission ratio from the second large pulley to the first small pulley is 31 / 97, or approximately 0.3196. That is, approximately 0.3196 revolutions of the second large pulley make one complete revolution of the first small pulley.

[0025] However, because the natural numbers 31 and 97 are relatively prime, a particular rotational position or set position of the belt drive defined by a particular rotational position of the first pulley and a particular rotational position of the second pulley will not be repeated until after the first pulley has rotated 97 complete revolutions and the second pulley has rotated 31 complete revolutions.

[0026] Thus, each combination of a specific rotational position of the first pulley and a specific rotational position of the second pulley can be uniquely assigned to a specific operating position of the belt drive along an operating path consisting of multiple complete revolutions of the first and / or second pulley.

[0027] The belt drives described herein may be used, for example, in steering of a motor vehicle, such that an axially parallel assembly may include, for example, one of the belt drives described above. The belt drive may transmit rotational motion from a first pulley disposed on an electric motor to a second pulley disposed on a ball screw drive, such that the ball screw drive is configured to convert the rotational motion into translational motion to affect or support steering.

[0028] Known belt drives for steering systems of motor vehicles have an operating range of about 80 to 120 complete revolutions of the motor-side pulley, i.e., can move or at least support the movement of the steering system for a motor vehicle from one maximum possible displacement position to the opposite maximum possible displacement position in about 80 to 120 complete revolutions of the pulley located on the electric motor.

[0029] The maximum possible number of rotations of the belt drive pulleys between the largest displacement positions determines the operating range of the belt drive. If the pulley size ratios are not chosen to be relatively prime, each combination of specific rotational positions of the two pulleys can be assigned to several possible belt drive positions in the operating range, i.e., several possible steering angles of the vehicle's wheels. Therefore, it is not possible to unambiguously identify the current steering angle of the vehicle based solely on the rotational positions of the pulleys identified by the sensor assembly.

[0030] However, if the pulley sizes are relatively prime and selected to match the length of the operating range and / or the maximum steering angle possible, then each combination of specific rotational positions is mapped to exactly one belt drive position and therefore unambiguously mapped to one steering angle of the vehicle wheels.

[0031] In one variant, the working range of the belt drive position can be defined as 80 to 120 revolutions, in particular 90 to 110 revolutions, of the maximum possible complete revolutions of the first pulley in a particular direction of rotation. A second integer multiple of the unit length corresponds to the diameter of the second pulley and can be formed by a product of a natural number and the unit length, which natural number can be greater than 80, in particular greater than 90 and / or greater than 100 and / or greater than 120.

[0032] The first pulley may be coupled to a rotor of a motor or electric motor, in particular a brushless electric motor. If desired, control or regulation of the motor or electric motor may be based on detection of the first sensor assembly. The brushless electric motor may be a permanent magnet synchronous motor (PMSM) or a brushless asynchronous machine. Effect of the Invention

[0033] One advantage here is that the detection of the first sensor assembly can serve at least two different purposes: firstly, to determine the position of the belt drive in its working range and / or to measure the steering angle of the steering system, and secondly, to regulate or control a motor or an electric motor coupled to the belt drive. The control of the motor can include, for example, a Field Oriented Control (FOC). On the one hand, this allows saving on sensors already required for regulating or controlling the motor, and also allows further benefits from the sensor assembly required for detecting the rotational position of the pulley.

[0034] Furthermore, the belt drive may comprise a temperature sensor configured to detect a temperature of the belt drive, in particular an ambient temperature of the belt. Alternatively or additionally, the belt drive may further comprise a temperature estimator configured to estimate a temperature of the belt drive, in particular an ambient temperature of the belt, based on modeling of the belt drive.

[0035] One advantage here is that a temperature compensation of the belt elasticity of the belt, in particular a first or second order temperature compensation, can be performed based on the detection of a temperature sensor and / or a temperature estimator.

[0036] Furthermore, the data processing device may be configured to measure a contraction or expansion of the belt based on detection of the first and second sensor assemblies and / or the temperature sensor and / or the temperature estimator. Alternatively or additionally, the data processing device may be further configured to measure a force acting on the belt drive, in particular the belt, based on detection of the first and second sensor assemblies and / or the temperature sensor and / or the temperature estimator.

[0037] One advantage here is that the first and second sensor assemblies, which can optionally be complemented by a temperature sensor and / or a temperature estimator, can also interact to form a force sensor, for example a force sensor for measuring the force acting on the steering of a vehicle while the vehicle is being driven. The acting force can be measured by detecting a contraction or extension of the belt and comparing this with previously measured and / or stored reference values.

[0038] In one embodiment, the data processing device is further configured to measure or estimate wear and / or damage to the belt drive, in particular the belt, based on current and / or recorded detections of the first sensor assembly and the second sensor assembly and / or the temperature sensor and / or the temperature estimator.

[0039] The detection of wear and / or damage may comprise a comparison of the detections, in particular of the first and second sensor assemblies and / or the temperature sensor, with a modelling of the belt. In particular, the modelling may be a virtual modelling of the belt drive, created in particular by an electronic data processing device, which models the technical and physical characteristics of the belt drive, which are then compared by the data processing device with the actual detections of the first and second sensor assemblies and / or the temperature sensor.

[0040] Furthermore, the data processing device may be further configured to measure and / or estimate undercooling and / or icing of the belt drive and / or devices coupled to the belt drive, in particular the ball screw drive, based on current and / or recorded detections of the first sensor assembly and the second sensor assembly and / or the temperature sensor and / or the temperature estimator.

[0041] Icing, for example of a ball screw drive, can occur, for example, when a motor vehicle equipped with a belt drive comes into contact with water in a subzero environment, for example at a car wash. Icing of the belt drive and / or of the devices connected to it can have a significant negative impact on the road safety of the motor vehicle. The undercooling and / or icing of the belt drive and / or of the devices connected to it, in particular of the ball screw drive, as well as the wear and / or damage of the belt drive, can also be measured by the data processing device by comparing the first and second sensor assemblies and / or the temperature sensor detections with a modeling of the belt. Here again, in particular, the modeling can be a virtual modeling of the belt drive created by the data processing device, in particular electronic, which models the technical and physical characteristics of the belt drive, which are then compared by the data processing device with the actual detections of the first and second sensor assemblies and / or the temperature sensors.

[0042] The above-mentioned belt drive can in particular be part of an axial parallel assembly or an axial parallel drive, in particular part of the steering of a motor vehicle. The belt drive and / or the axial parallel assembly or the axial parallel drive with the belt drive can further be part of a motor vehicle, in particular part of the steering of a motor vehicle.

[0043] If required, the data processing device can also be configured to issue a warning message to the driver of the vehicle and / or to stop the vehicle upon detection of wear and / or damage, and / or undercooling and / or icing of the belt drive, in particular the belt, and / or of a device coupled to the belt drive, in particular the ball screw drive.

[0044] One advantage here is that if the need for vehicle maintenance is predicted, the vehicle driver can be notified, for example by a visually and / or audibly perceptible warning message, and the data processing device can also shut down the vehicle if a dangerous situation is detected.

[0045] The method for measuring the rotational position of a pulley in a belt drive is as follows: Providing a first pulley having a first diameter; Providing a second pulley having a second diameter; providing a belt disposed on each side of the first and second pulleys and configured to transmit rotational motion of the first pulley to the second pulley; sensing a rotational position of the first pulley with a first sensor assembly; sensing a rotational position of the second pulley with a second sensor assembly; Including, The first diameter corresponds to a first integer multiple of a unit length, and the second diameter corresponds to a second integer multiple of the same unit length, and the first and second integer multiples of the unit length are different and relatively prime to each other.

[0046] Furthermore, the method for measuring the rotational position of a pulley of the belt drive device includes the steps of: providing a data processing device; Based on detection of the first sensor assembly and detection of the second sensor assembly, the method can include determining an unambiguous rotational or set position of the belt drive along a set path consisting of multiple complete revolutions of the first and / or second pulleys.

[0047] Further configurations, properties, advantages and possible improvements of the belt drive will become apparent to those skilled in the art from the following description, which refers to the accompanying schematic drawings, in which the dimensions and proportions of the components shown in Figure 1 are not to scale. [Brief description of the drawings]

[0048] [Figure 1] 1 is an example of a belt drive device 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] 1 shows an example of a belt drive 100 having a first pulley 10 and a second pulley 20. The first pulley 10 is mounted to rotate about a first axis of rotation X1, and the second pulley 20 is mounted to rotate about an axis of rotation X2.

[0050] FIG. 1 also shows a belt 30 that is in each case disposed on the sides of the first pulley 10 and the second pulley 20 and that is configured to transmit the rotational motion of the first pulley 10 to the second pulley 20 .

[0051] Additionally, pulleys 10 and 20 are not shown precisely to scale, but have a ratio of sizes that corresponds to the ratio of two relatively prime natural numbers.

[0052] In either case, the rotational position of pulleys 10 and 20 is sensed by a sensor assembly having at least one sensor each. The rotational position of the first pulley is sensed by a first sensor assembly (not shown). The rotational position of the second pulley is sensed by a second sensor assembly (not shown).

[0053] The first and second sensor assemblies are configured to measure the rotational position of the first pulley 10 and the second pulley 20. The first and second sensor assemblies measure how many degrees each pulley has rotated relative to a predefined zero position.

[0054] The sensor assembly transmits the detected rotational positions of pulleys 10 and 20, respectively, to an electronic data processing device (not shown). The data processing device uses the two rotational positions of pulleys 10 and 20 to determine an adjustment position for the belt drive on a set path consisting of multiple complete revolutions of the first and second pulleys.

[0055] Because the size ratio of pulleys 10 and 20 corresponds to the ratio of two relatively prime numbers, a set position of the belt drive consisting of multiple complete revolutions of the first and second pulleys will only be the same after many complete revolutions of the two pulleys. Only after the number of complete revolutions of the smaller pulley about its axis of rotation exceeds the magnitude of the larger natural number in the pulley size ratio will a particular combination of rotational positions of the first pulley 10 and the second pulley 20 become unambiguously assignable to a set position of the belt drive on a set path consisting of multiple complete revolutions of the first and second pulleys.

[0056] In the illustrated example, the maximum rotational speeds of the two pulleys 10 and 20 are limited by external conditions so that each combination of rotational position of the first pulley 10 and the second pulley 20 can be assigned to exactly one adjustment position of the belt drive 100.

[0057] Each combination of a specific rotational position of the first pulley 10 and a specific rotational position of the second pulley 20 can thus be uniquely assigned to a specific set position of the belt drive 100 along a set path consisting of multiple complete revolutions of the first and second pulleys.

[0058] The illustrated belt drive 100 can be used, for example, in steering an automobile, which can include, for example, a parallel-axis assembly with, for example, one of the belt drives 100 described above. The belt drive 100 can transmit rotational motion from a pulley disposed on an electric motor to a second pulley disposed on a ball screw drive configured to convert the rotational motion into translational motion to affect or support steering.

[0059] As outlined above, when belt drive 100 is used to steer a vehicle, the rotational positions of each of pulleys 10 and 20 can be uniquely assigned to the position of the steering mechanism and thereby the toe angle of the wheels of the vehicle being moved by the steering. Thus, the position of the steering mechanism and / or the toe angle of the wheels of the vehicle being moved by the steering can be determined without any additional sensors within the steering mechanism or even without the rotation history of the pulleys.

[0060] If desired, the control of a motor coupled to a pulley, in particular an electric motor, can be based on the detection of one of the sensor assemblies detecting the rotational position of the pulley, thereby making it possible to avoid the need for additional sensors for power-assisted or fully electric steering. In particular, a motor can be coupled to the first pulley 10 and controlled based on the detection of the first sensor assembly.

[0061] The above-mentioned variations of the device, as well as its configuration and operation form, are merely intended to provide a better understanding of the structure, operation mode and characteristics, and are not intended to limit the disclosure to the objects shown in the figures. The figures are highly schematic, and therefore some essential characteristics and effects are greatly exaggerated in order to clarify the function, operation principle, technical form and configuration.

[0062] The scope of the claims does not limit the disclosure of all features described herein, and therefore does not limit all possible combinations of features, all features disclosed are expressly disclosed herein individually or in combination with all other features.

Claims

1. A belt drive (100), comprising: A first pulley (10) having a first diameter (D1); a second pulley (20) having a second diameter (D2); a belt (30) arranged in each case on the sides of the first and second pulleys and configured to transmit the rotational motion of the first pulley (10) to the second pulley (20); a first sensor assembly arranged and configured to detect a rotational position of the first pulley (10); a second sensor assembly arranged and configured to detect the rotational position of the second pulley (20); The first diameter (D1) corresponds to a first integer multiple of a unit length, The second diameter (D2) corresponds to a second integer multiple of the same unit length, A belt drive device (100) characterized in that the first and second integer multiples of the unit length are different from each other and relatively prime.

2. 2. The belt drive (100) of claim 1, wherein the first diameter (D1) and / or the second diameter (D2) corresponds to a product of the unit length and a prime number.

3. the first sensor assembly is a non-contact position detection sensor, in particular a non-contact inductive position detection sensor; and / or The belt drive (100) according to any of claims 1 and 2, characterized in that the second sensor assembly comprises a non-contact type position detection sensor, in particular a non-contact type inductive position detection sensor.

4. At least a portion of the first sensor assembly is integrated into and / or coupled to the first pulley (10); and / or The belt drive device (100) of any one of claims 1 to 3, characterized in that at least a portion of the second sensor assembly is integrated into and / or coupled to the second pulley (20).

5. The belt drive (100) of any one of claims 1 to 4, further comprising a data processing device configured to unambiguously measure a rotational position or a set position of the belt drive (100) on a set path consisting of multiple complete rotations of the first (10) and / or second (20) pulleys based on detection of the first sensor assembly and detection of the second sensor assembly.

6. said first pulley (10) being connected to a rotor of a motor or electric motor, in particular a brushless electric motor; The belt drive (100) according to any one of claims 1 to 5, characterized in that the control or regulation of the motor or the electric motor is based on the detection of the first sensor assembly.

7. a temperature sensor configured to detect the temperature of the belt drive, in particular the environmental temperature of the belt (30); and / or The belt drive (100) according to any one of claims 1 to 6, further comprising a temperature estimator configured to estimate a temperature of the belt drive, in particular an environmental temperature of the belt (30), based on modeling of the belt drive.

8. the data processing device is configured to measure a contraction or expansion of the belt (30) based on detection of the first and second sensor assemblies and / or the temperature sensor and / or the temperature estimator; and / or The belt drive device (100) according to any one of claims 5 to 7, characterized in that the data processing device is further configured to measure the force acting on the belt drive device (100), in particular the belt (30), based on the detection of the first sensor assembly and the second sensor assembly and / or the temperature sensor and / or the temperature estimator.

9. The belt drive (100) of any one of claims 5 to 8, characterized in that the data processing device is further configured to measure or estimate wear and / or damage to the belt drive (100), in particular to the belt (30), based on current and / or recorded detections of the first sensor assembly and the second sensor assembly and / or the temperature sensor and / or the temperature estimator.

10. The belt drive (100) according to any one of claims 5 to 9, characterized in that the data processing device is further configured to measure and / or estimate undercooling and / or icing of the belt drive and / or of a device coupled to the belt drive, in particular a ball screw drive, based on current and / or recorded detections of the first sensor assembly and the second sensor assembly and / or the temperature sensor and / or the temperature estimator.

11. A axial parallel drive device, 11. An axial parallel drive comprising a belt drive according to any one of claims 1 to 10.

12. 1. An automobile steering system for a motor vehicle, comprising: A belt drive according to any one of claims 1 to 10 and / or 12. A steering system for a motor vehicle, comprising an axial parallel drive device according to claim 11.

13. 13. The vehicle steering system for a motor vehicle according to claim 12, characterized in that the data processing device is further configured to issue a warning message to the driver of the motor vehicle and / or to stop the motor vehicle upon detection of wear and / or damage, and / or undercooling and / or icing of the belt drive (100), in particular the belt (30) and / or of a device coupled to the belt drive, in particular a ball screw drive.

14. A method for measuring the rotational position of a pulley of a belt drive (100), comprising the steps of: Providing a first pulley (10) having a first diameter (D1); Providing a second pulley (20) having a second diameter (D2); providing a belt (30) arranged in each case on the sides of the first and second pulleys and configured to transmit the rotational movement of the first pulley (10) to the second pulley (20); detecting a rotational position of the first pulley (10) with a first sensor assembly; detecting the rotational position of the second pulley (20) with a second sensor assembly; Including, A method for measuring the rotational position of a pulley of a belt drive device (100), characterized in that the first diameter (D1) corresponds to a first integer multiple of a unit length, and the second diameter (D2) corresponds to a second integer multiple of the same unit length, and the first and second integer multiples of the unit length are different and relatively prime.

15. 15. The method of claim 14, further comprising the step of unambiguously determining a rotational or set position of the belt drive (100) on a set path consisting of multiple complete revolutions of the first (10) and / or second (20) pulleys based on detection of the first sensor assembly and detection of the second sensor assembly.

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