Patent Application
20220034643
The present invention relates to a rotational speed and/or rotational angle detection unit and a working device. The present invention relates in particular to a torque detection device for in particular actively detecting a rotational speed and/or a rotational angle of a shaft, in particular a crankshaft, of a working device, in particular a vehicle, that is drivable by muscular power and/or by motor power about a rotational axis of the crankshaft, and a working device, a vehicle, a bicycle, an electric bicycle, an e-bike, a pedelec, or the like, that is drivable by muscular power and/or by motor power.
In the monitoring and/or control of drive devices, for example in the field of automotive engineering, it is often desirable to detect a rotational speed and/or a rotational angle, and thus an orientation, of an underlying shaft of a drive unit.
For this purpose, it is customary to use mechanical means, for example, for sampling a surface of the shaft in order to allow a rotational speed and/or a rotational angle, and thus an orientation of the shaft, to be deduced via a direct mechanical coupling.
The insufficient accuracy in the mechanical tapping and the influence of the mechanical tapping on the rotation and the orientation of the underlying shaft are disadvantageous.
The rotational speed and/or the rotational angle detection unit according to the present invention may have the advantage that without special mechanical precautions in the area of the shaft to be examined, a rotational speed and/or a rotational angle, and thus an orientation, of the underlying shaft may be ascertained with a high level of reliability and accuracy. This is achieved according to the present invention via the features in accordance with an example embodiment, in that a rotational speed and/or rotational angle detection unit for detecting a rotational speed and/or a rotational angle of a shaft, in particular a crankshaft, of a working device, in particular a vehicle, that is drivable about a rotational axis of the crankshaft by muscular power and/or or by motor power is provided, including (i) a surface structure that is materially and/or magnetically formed on a surface of the crankshaft, and (ii) a sensor unit that is designed to detect a magnetic field carried by the shaft and by the surface structure. By use of the measures according to the present invention, the rotational speed and/or the rotational angle of the underlying shaft and its rotational axis may be detected, without mechanical tapping and without mechanical coupling, by detecting magnetic signals at or in the shaft, and thus in a wear-free manner and with a higher level of accuracy.
By use of the measures according to the present invention and in particular by the contact-free detection of the rotational speed and the rotational angle, and thus of the time-dependent position of the shaft in relation to the rotational axis, a particularly high level of failure-free operation results for the measured value detection. In particular, the modulation of the magnetic field carried and/or emitted by the shaft via the surface structure is advantageously utilized, whether it is designed and configured mechanically and/or magnetically.
Preferred refinements and embodiments of the present invention are described herein.
According to one advantageous refinement of the rotational speed and/or rotational angle detection unit according to the present invention, a particularly high level of reliability in determining the rotational speed and/or the rotational angle of the shaft results when the surface structure is designed as an encoding item, in particular for an angular position of the crankshaft about the rotational axis. In this way, the orientation of the shaft in relation to the rotational axis of the shaft may be ascertained at any point in time, and the rotational speed of the shaft may also be determined from the time dependency of the orientation.
In general, there are numerous options for designing the surface structure on the surface of the underlying shaft. In general, all measures that are usable for a discrimination of the position of the shaft in relation to the rotational axis with angular resolution in the circumferential direction of the shaft may be used alone or in combination with one another.
In one particularly simple example embodiment of the rotational speed and/or the rotational angle detection unit according to the present invention, the surface structure is designed as a mechanical structure (i) including a sequence of elevations, depressions, and/or recesses, (ii) including a sequence of one or multiple ramp(s) with a particular edge at one end of the ramp, and/or (iii) as a knurl on or in the surface of the shaft, in each case in a circumferential direction of the shaft.
Alternatively, permanent magnetic encoding that is applied to the surface or incorporated into the surface may be present. This is possible, for example, in the sense of local permanent magnetic areas.
Magnetic structuring and mechanical structuring may be combined with one another.
The encoding may be applied in the surface and in the circumferential direction of the shaft by appropriate different lengths or angular extensions of the mechanical and/or magnetic areas.
To increase the sensitivity and thus the measuring accuracy, according to a further exemplary embodiment of the rotational speed and/or the rotational angle detection unit according to the present invention, it is provided that the sensor unit includes at least one receiver coil and/or a core, in particular containing or made of a ferromagnetic material, a particular receiver coil being designed as a measuring coil and/or a sensing coil.
Although a magnetic field that is inherently present in the shaft may be used in conjunction with the sensor unit for detecting the rotational angle and/or the rotational speed of the shaft, according to another preferred embodiment of the rotational speed and/or the rotational angle detection unit according to the present invention it is particularly advantageous when it is designed to actively detect the rotational speed and/or the rotational angle of the shaft, and for this purpose in particular is configured with an excitation unit that is designed to act on the shaft with a magnetic field that is in particular temporally variable.
In this regard, it is particularly advantageous when the excitation unit includes an exciter, in particular made up of or including a solenoid, with a core and/or containing or made of a ferromagnetic material.
Various configurations of excitation units are possible. In addition to explicitly providing a dedicated excitation unit, it is also possible to utilize devices that are designed in conjunction with other units and that are used to apply a magnetic field to the shaft to be measured.
Thus, in another preferred specific embodiment of the rotational speed and/or the rotational angle detection unit according to the present invention, the excitation unit is designed as a unit that is external to the sensor unit and/or as an excitation unit of a torque detection device.
In this specific embodiment, it is particularly advantageous that in a torque detection device that operates based on a magnetic field and is designed to actively act on the shaft with a magnetic field, an excitation unit, which is already present there by necessity, may also be utilized to generate the magnetic field with regard to the determination of the rotational speed and the rotational angle. Costs are thus saved, the number of necessary components is reduced, and a more compact design results for the actual rotational speed and/or rotational angle detection unit.
A particularly high level of compactness in the design of the rotational speed and/or the rotational angle detection unit according to the present invention may be achieved when the sensor unit, in particular a particular receiver coil of the sensor unit, and/or a particular exciter, in particular a particular solenoid of the excitation unit or of the exciter, are/is designed, at least in part, as a structure of a circuit board or conductor plate or a plurality of same.
For actually determining the values of the rotational speed and/or of the rotational angle of the underlying shaft, in one preferred embodiment of the rotational speed and/or the rotational angle detection unit according to the present invention an evaluation and control unit is provided that is configured to (i) receive values, representative of the detected magnetic fields, that are output by the sensor unit and (ii) determine the value of a rotational speed and/or of a rotational angle of the shaft, based on the received values.
Moreover, in the sense of an application, the present invention relates to a working device and in particular a vehicle that is drivable by muscular power and/or or by motor power, in particular a bicycle, an electric bicycle, an e-bike, a pedelec, or the like, including at least one wheel, a drive for driving the at least one wheel, and a rotational speed and/or a rotational angle detection unit designed according to the present invention for detecting a rotational speed and/or a rotational angle of a shaft of the drive, in which the drive is monitorable and/or controllable based on the detected rotational speed and/or the detected rotational angle.
Specific embodiments of the present invention are described in greater detail with reference to the figures.
Exemplary embodiments of the present invention are described in greater detail below with reference to
The described features and other properties may be arbitrarily separated from one another and arbitrarily combined with one another without departing from the core of the present invention.
Initially, with reference to
Vehicle 1 as an electric bicycle includes a frame 12 at which a front wheel 9-1, a rear wheel 9-2, and a crank mechanism 2 that includes two cranks 7, 8 with pedals 7-1 and 8-1 are situated. An electric drive 3 is integrated into crank mechanism 2. A sprocket 6 is situated at rear wheel 9-2.
A drive torque that is provided by the rider and/or by electric drive 3 is transmitted from a chain ring 4 at crank mechanism 2 to sprocket 6 via a chain 5.
In addition, a control unit 10 that is connected to electric drive 3 is situated at the handlebars of vehicle 1. Furthermore, a battery 11 that is used to supply power to electric drive 3 is provided in or at frame 12.
In addition, a crank bearing 13 or bottom bracket ball bearing that includes a crank housing 14 and a crankshaft 15 is integrated into frame 12.
Thus, as a whole, drive 80 of vehicle 1 according to the present invention includes crank mechanism 2 for actuation by the rider with the aid of muscular power, and additional or alternative electric drive 3.
In addition, one specific embodiment of rotational speed and/or rotational angle detection unit 100 according to the present invention is provided in the area of drive 80 in order to detect the rotational speed and/or the rotational angle of crankshaft 15.
With reference to the tripod illustrated in
The basic structure of rotational speed and/or rotational angle detection unit 100 is most easily discernible from the top view according to
The specific embodiment of rotational speed and/or rotational angle detection unit 100 according to the present invention illustrated in
Sensor unit 30 is used as a measuring sensor device, or measuring sensor for short, and includes a receiver coil 31-1 that surrounds or encloses a core 31-2, for example containing or made of a ferromagnetic material.
An exciter 21 of an excitation unit 20, in particular in the form of a solenoid 21-1 that includes core 21-2 as part of excitation unit 20, is combined with receiver coil 31-1.
It is apparent from the illustrations in
Sensor unit 30 and excitation unit 20 are arranged and oriented in such a way that in a projection, the axes of coils 31-1, 21-1 and the axis of shared core 31-2, 21-2 are situated on the projection of rotational axis X. In this way, the magnetic field that is excited by excitation with the aid of excitation unit 20, and carried by shaft 15, may be detected in a particularly accurate manner.
It is clear from these illustrations that receiver coil 31-1 of sensor unit 30 and solenoid 21-1 of excitation unit 20 are associated with one another and include a shared core 21-2, 31-2, and that solenoid 21-2 of exciter 21 of excitation unit 20 is situated directly above associated receiver coils 31-1 of sensor unit 30, which functions as a measuring sensor.
Shaft 15 with surface 15a is situated in the immediate vicinity of receiver coil 31-1 and spaced apart from same, on the side of receiver coil 31-1 facing away from solenoid 21-2 of exciter 21 of excitation unit 20. The spatial distance from surface 15a is selected in such a way that the magnetic field that is excited by excitation unit 20 in shaft 15 and carried by shaft 15 may be detected in a particularly accurate manner.
A modulation of the magnetic field that is carried by shaft 15 and active at the location of sensor unit 20 is necessary for detecting the rotational speed and/or the rotational angle. This is achieved according to the present invention by forming a surface structure 40 on surface 15a of shaft 15 in the area which with the rotation of shaft 15 gets into the vicinity of sensor unit 20, and in particular of receiver coil 21-1.
In the specific embodiment shown in
In this way, sensor unit 30 measures the magnetic field carried by shaft 15 with a particularly high degree of sensitivity.
An aspect of the specific embodiment in
The specific embodiment of rotational angle detection unit 110 shown here is based on the following key aspects:
In the specific embodiment of rotational speed and/or rotational angle detection unit 100 according to the present invention together with torque detection device 110 illustrated in
First sensor unit 130 is used as a measuring sensor device, or measuring sensor for short, and includes four receiver coils 131 that may be situated, for example, at the end points of a vertical, flat cross that is provided with sides of equal length. An excitation unit 120 that includes a solenoid 121 with core 122 as part of an excitation unit 120 is situated in the center of the cross, i.e., the intersection point.
First sensor unit 130 as a measuring sensor device is oriented with its alignment cross in such a way that rotational axis X in a projection encloses an angle of 45 degrees with the sides of the alignment cross of first sensor unit 130. In this way, the magnetic field that is excited by excitation with the aid of excitation unit 120, and carried, by shaft 15 may be detected in a particularly accurate manner.
In addition to first sensor unit 130, it is possible, as shown in the specific embodiment in
In this context, “congruent” means that both sensor units 130, 140 of torque detection device 110 have the same number of receiver coils 131 or 141, for example four, which are in a 1-to-1 association with one another, it being possible for mutually associated coils 131 and 141, as shown in this specific embodiment, to be situated coaxially and in the immediate spatial vicinity or proximity of one another, so that the end points, the sides, and also the intersection points of the particular crosses coincide, the intersection points in a projection onto one another being situated on rotational axis X or on the projection of same.
First sensor unit 130 and second sensor unit 140 from
During operation, the two sensor units 130 and 140 of torque detection device 110 are excited by a shared excitation unit 120 that includes an exciter in the form of a solenoid 121 and a core 122 that is enclosed by solenoid 121, also facilitated by the field that is emitted from crankshaft 15. The exciter together with solenoid 121 is situated at, in, or in the area of the intersection point in such a way that a symmetrical arrangement made up of excitation unit 120 and sensor units 130, 140 of torque detection device 110 results overall.
It is clear from the illustrations in
In this way, first sensor unit 130 of torque detection device 110 measures the magnetic field carried by shaft 15 with a particularly high degree of sensitivity, including the interference signals, whereas second sensor unit 140 of torque detection device 110 receives these combined signals in the same way, but compensates for the interference signal components due to the different electrical economy circuit.
In addition, this procedure particularly advantageously allows a difference formation of the signals that are output by first and second sensor units 130 and 140 of torque detection device 110, optionally in a weighted and/or postprocessed form, to allow the interfering influences to be filtered out, and the effect on the carried magnetic field generated by the acting torque to be detected in a particularly accurate manner, in particular with the objective of determining the value of the acting torque in a preferably accurate and interference-free manner.
The illustration is selected in such a way that particular surface structure 40 on surface 15a appears to have an angled shape, i.e., planar, in each case corresponding to an unwound peripheral angle or roll-off angle α between 0° and 360°.
In the specific embodiment according to
In the specific embodiment according to
It is apparent in particular from the illustration in
These and further features and properties of the present invention are explained in greater detail in the following discussion:
One aspect of the present invention lies in developing an active sensor for detecting the rotational speed and/or rotational angle at a stationary or rotating shaft. Examples of such rotating shafts are the crankshafts of bicycles, electric bicycles, e-bikes, pedelecs, or the like.
One intent of the present invention in particular is to achieve an improvement with regard to the susceptibility to interference with respect to the rotation of the shaft, for example due to a nonideal geometry of shaft 15, vibrations, mechanical and/or temperature changes, and the like.
A main feature of the present invention is to provide a surface structure 40 that is provided on or in surface 15a of underlying shaft 15 and used to modulate a carried magnetic field, inherently or actively generated by shaft 15, in such a way that a type of encoding for the rotational angle and/or for the rotational speed takes place.
An active magnetic measurement takes place at low working frequencies, in particular in the range of less than 5 kHz, preferably in the range of less than 3 kHz.
Analog and/or digital signal processing is used for improved signal resolution and to increase the signal-to-noise ratio. Temperature compensation is also possible here.
In one specific embodiment of the present invention, underlying excitation unit 20 may be formed from an excitation unit 120 of a cooperating torque detection device 110, which may be designed in particular with congruent first and second sensor units 130 and 140.
In this regard, first and second sensor units 130 and 140 may also be understood as two independent sensor heads, one for detection and one for compensation.
In conjunction with the figures, coil cores 121-2, 131-2, and 141-2 are shown with different geometries at the side facing shaft 15. This side, as an end surface, may be adapted planarly, convexly, circularly, conically, and/or locally to the surface shape of shaft 15, for example concavely in the manner of a section or cutout of the inner surface area of a circular cylinder and conforming to the outer surface area of shaft 15.
In one preferred specific embodiment of torque detection device 110, the following may be provided:
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2018 221 211.2 | Dec 2018 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/083007 | 11/29/2019 | WO | 00 |
