Crank gear with a crankshaft for connection to at least one foot or hand crank

Abstract

Crank mechanism with a crankshaft (5) for connection with at least one foot or hand crank and at least one gear wheel (1) driven by means of the crankshaft (5), characterized in that a coupling unit (10) is provided between the crankshaft (5) and the gear wheel (1), wherein the coupling unit (10) has, at least temporarily under load, an angular offset between a crank-side receiving area (11) and a delivery area (12) connected to the gear wheel (1) for receiving and delivering the torque generated by the crank. wherein a converter unit for converting the angular displacement into a change in magnetic flux and that a magnetic field-sensitive sensor for detecting the angular displacement is provided, characterized in that the converter unit comprises at least one magnet (15) and two mutually rotatable magnetic guiding elements (21, 22) which, within an air gap (25), change the shape of the air gap (25) depending on the angle by their shape and their relative angular position, wherein the magnetic field-sensitive sensor, in particular a Hall sensor (19) or the like, is provided to detect changes in a magnetic flux, and wherein the magnet is a ring magnet (15) arranged concentrically to the crankshaft (5), such that an outer return circuit (17) of the magnetic flux runs around the outer circumference of the ring magnet (15) and an inner return circuit (18) of the magnetic flux runs around the inner circumference of the ring magnet (15), wherein the angle-dependent changing area of ​​the air gap (25) is located in the area of ​​the outer return circuit (17) and the magnetic field-sensitive sensor (19) is located in the area of ​​the inner return circuit (18) or vice versa.

Description

[0001] The invention relates to a crank mechanism with a crankshaft for connection with at least one foot or hand crank according to the preamble of claim 1.

[0002] A crank gear according to the invention is understood to be any gear for vehicles in which a drive is provided by a crank which is set in rotation by a person using physical force and this torque is transmitted from there via a mechanical gear to at least one propulsion element such as a wheel or a paddle wheel, i.e. in addition to conventional bicycle gears also gears for multi-wheeled vehicles and / or additionally motor-driven vehicles such as so-called e-bikes or pedelecs as well as other such vehicles such as pedal boats or the like.

[0003] Crank gears for bicycles according to the preamble of claim 1 have been commercially available for some time.

[0004] German patent application DE 198 16 568 A1 discloses a sensor arrangement for detecting torque and / or angle of rotation. This sensor arrangement incorporates a torsion element on a shaft through a cross-sectionally tapered design. The rotation of the shaft under load, or the resulting angle of rotation, is detected by a magnetic sensor, and the applied torque is determined based on this angle of rotation.

[0005] Further gearboxes are known from documents DE 10 2007 046 749 A1, DE 196 09 981 A1, DE 10 2007 062 156 A1 and DE 198 16 568 A1.

[0006] In contrast, the invention aims to propose a crank mechanism in which the torque introduced into a crank mechanism via a crankshaft can be detected by sensors.

[0007] This problem is solved starting from a crank mechanism according to the preamble of claim 1 by its characterizing features.

[0008] Accordingly, a transmission according to the invention has a coupling unit between the crankshaft and at least one gear wheel driven by means of the crankshaft, which under load has a torque-dependent angular offset between a crank-side receiving area, which receives the torque generated by means of the crank, and a delivery area, which delivers the torque to the gear wheel.

[0009] By detecting this angular offset through the generation of a sensor signal corresponding to the magnitude and / or direction of rotation of the angular offset, it is possible to deduce or determine the magnitude and / or direction of rotation of the recorded torque.

[0010] Detecting the direction of rotation of the recorded torque can be advantageous, for example, when using a so-called coaster brake.

[0011] The measurement of the applied torque can be used, if necessary in conjunction with transmission data, to record data such as the generated power, cranking force, etc. Such data can be further used for storage and display to a driver or for control purposes, e.g., for automatic transmission or for controlling an auxiliary drive.

[0012] The features claimed in the dependent claims result in advantageous further developments and embodiments of the invention.

[0013] According to the invention, a converter unit for converting the angular displacement into a change in magnetic flux and a magnetic field-sensitive sensor for detecting this change are provided. This represents a cost-effective, reliable, and space-saving design.

[0014] A simple method for generating a torque-dependent angular displacement is preferably available using a torsion element. For the angular displacement to depend on the applied torque, the torsion element is at least partially elastic, meaning it can be deformed against a restoring torque. This restoring torque depends on the degree of deformation and thus on the load or the applied torque, so that the magnitude of the resulting angular displacement also depends on the magnitude of the applied torque. Furthermore, the restoring torque causes the torsion element to return to its original shape when the load decreases.

[0015] Advantageously, the torsion element is arranged in a cavity of the crankshaft. This allows the torsion element to have a certain length, if required, while still being compact. Furthermore, the coupling point for connecting to the driven gear can be easily positioned precisely where the gear is located within the cavity. The connection between the torsion element and the crankshaft can be made in close proximity to the crank, ensuring that the torque applied by the crank is fully transmitted to the torsion element and that any resulting angular misalignment is accurately reproduced.

[0016] In such an application, the torsion element is expediently a torsion rod with the corresponding length extension between the connection points.

[0017] The gear wheel is typically designed as a toothed gear and can be driven by a connecting element between the torsion element and the gear wheel. Such a connecting element is particularly advantageous when arranged in a continuous, at least partially hollow crankshaft, as it can penetrate the wall of the hollow shaft and thus bridge the gap between the torsion element and the gear wheel.

[0018] To limit the variable angular offset and / or to protect the torsion element against over-rotation, a mechanical end stop is preferably provided. This can be formed, for example, by the edge of an elongated hole through which the connecting element passes.

[0019] According to the invention, the transducer unit is designed to convert the angular misalignment into a change in magnetic flux. For this purpose, at least one magnet and at least two mutually rotatable guide elements are provided. The guide elements are shaped and arranged such that they change the shape of an air gap located within the magnetic field of the magnet depending on their relative angular position to one another. This angle-dependent change in the air gap causes an angle-dependent change in the total magnetic flux return. Thus, by detecting a change in magnetic flux at another location, the angular misalignment can be detected and evaluated.

[0020] In a particular embodiment of the invention, one guide element is provided with a toothed inner circumference and the other guide element with a toothed outer circumference, such that the shape of the air gap depends on the angular position of these teeth. The two guide elements can be dimensioned such that the toothed outer circumference can rotate within the toothed inner circumference, allowing both guide elements to be arranged axially at the same height, nested within one another.

[0021] A Hall sensor, for example, is used as a magnetic field-sensitive sensor, with which the aforementioned changes in magnetic flux can be detected effectively.

[0022] The magnetic field-sensitive sensor is still preferably placed at a distance from the two guide elements in a structurally suitable location where there is a sufficient magnetic flux for measurement.

[0023] According to the invention, a ring magnet is arranged concentrically to the crankshaft, so that an outer return circuit of the magnetic field is formed outside the outer circumference of the ring magnet and an inner return circuit of the magnetic field is formed inside the inner circumference of the ring magnet.

[0024] According to the invention, the angle-dependent variable air gap area is located in the area of ​​the outer feedback circuit and the magnetic field-sensitive sensor is located in the area of ​​the inner feedback circuit, or vice versa.

[0025] Since changes in magnetic flux caused by changes in the conductive elements affect both feedback circuits, the sensor can be positioned at a distance from the conductive elements. This significantly simplifies the design.

[0026] After sensory detection of the flow change, the sensor signal can be used by an evaluation unit to determine the applied torque.

[0027] By appropriately arranging the rotatable guide elements within the angular range to be detected and / or by using multiple sensors, it is also possible to detect the direction of rotation with the same arrangement.

[0028] The invention, particularly in conjunction with the described further developments, enables robust, space-saving and cost-effective sensor technology.

[0029] An embodiment of the invention is shown in the drawing and is explained in more detail below with reference to the figures.

[0030] In detail, they show Fig. 1 a longitudinal section through various transmission components and the sensors for the torque of the transmission according to the invention, Fig. 2 a top view of two guide elements rotatable relative to each other in a first angular position, Fig. 3 a top view of two guide elements rotatable relative to each other in a second angular position and Fig. 4 A perspective view of the crankshaft with a connecting pin as a drive element

[0031] Fig. Figure 1 shows the essential components of a transmission according to the invention. Specifically, these are various transmission gears (1, 2, 3, 4), the first of which (1) is driven via a crankshaft (5).

[0032] The crankshaft 5 is provided on both sides with teeth (6, 7) for mounting foot or hand cranks. A connecting pin (8) protrudes from the crankshaft and serves to connect the driven gear wheel (1), as will be explained further below.

[0033] In Fig. Figure 1 shows the inner cavity (9) of the crankshaft (5) in which a torsion rod (10) is arranged. The torsion rod is non-rotatably connected to the crankshaft at its crank-side receiving area (11), for example by press fitting, welding, or shrink fitting. At its opposite discharge area (12), the torsion rod (10) is non-rotatably connected to the gear wheel (1) by means of the connecting pin (8) as a drive element for the gear wheel (1). To enable the angular offset according to the invention, the passage (13) through the wall of the crankshaft (5) is designed as an elongated hole (see Figure 1). Fig. 4), the edge (14) of which forms a mechanical end stop for the rotation of the connecting pin in the passage (13).

[0034] A ring magnet (15) is inserted into a recess (16) of the gear wheel (1), with the two magnetic poles N,S arranged in an axial direction. This results in an outer feedback circuit (17) and an inner feedback circuit (18), as indicated by the arrow lines.

[0035] A Hall sensor (19) is arranged in the area of ​​the inner feedback circuit. An annular space (20) is provided for the arrangement of the Fig. 1 guide elements not shown are arranged outside the Hall sensor (19) and extend far into the area of ​​the outer feedback circuit (18).

[0036] In the Fig. 2 and Fig. Figure 3 shows the guide elements (21, 22) to be accommodated in the annular space (20). The outer guide element (21) and the inner guide element (22) are provided with an internal toothing (23) and an external toothing (24), respectively, which protrude into an air gap (25).

[0037] The toothed sections (23, 24) form the contours of the air gap (25), whereby the shape of the air gap (25) can be changed by rotating the guide elements (21, 22). Fig. 2 and Fig. Figure 3 shows two different angular positions of the guide elements (21, 22) relative to each other. The toothed sections (23, 24) and the air gap (25) are located in the area of ​​the outer feedback circuit (17). However, by rotating the guide elements (21, 22), the flux of the magnetic field in the inner feedback circuit (18) is also changed and can thus be detected by the Hall sensor (19), whereby the Fig. 2 and Fig. 3. Illustrate the use of multiple Hall sensors.

[0038] The inner guide element (22) is rotationally fixed to the crankshaft, and the outer guide element (21) is fixed to the gear wheel (1). Thus, the angular offset generated by the torsion element (10) is established between the two guide elements (21, 22). The two guide elements (21, 22), the ring magnet (15), and at least one Hall sensor (19) therefore form a converter unit according to claim 1.

[0039] The described arrangement is capable of converting a torque applied to the crankshaft (5) by a person's physical force via a crank into a sensor-detectable angular displacement. For this purpose, the torsion rod, acting as a torsion element (10), absorbs the torque and twists under the corresponding load. This can occur if the gearbox initially opposes the torque, for example, by means of a drive wheel driven by the gearbox. This results in an angular displacement along the torsion rod (10) and thus between the receiving area (11) and the output area (12).

[0040] Since the torsion rod (10) is non-rotatably connected to the gear wheel (1) via the connecting pin (8), this angular offset also occurs between the guide elements (21, 22), which leads to a change in the flux of the magnetic field of the ring magnet (15). This flux change is detected by the Hall sensor (19). Reference symbol list: 1 gear 2 Gear 3 Gear 4 Gear 5 Crankshaft 6 gear teeth 7 Gearing 8 connecting pins 9 Cavity 10 Torsion rod 11 Recording area 12 Delivery area 13 Passage 14 Rand 15 Ring magnet 16 Exclusion 17 Back-end loop 18 Back-end loop 19 Hall sensor 20 Ring-shaped room 21 Guide element 22 Guide element 23 Internal teeth 24 External teeth 25 air gap

Claims

[1] Crank mechanism with a crankshaft (5) for connection with at least one foot or hand crank and at least one gear wheel (1) driven by means of the crankshaft (5), characterized by , that a coupling unit (10) is provided between the crankshaft (5) and the gear wheel (1), wherein the coupling unit (10) has, at least temporarily under load, an angular offset between a crank-side receiving area (11) and a delivery area (12) connected to the gear wheel (1) for receiving and delivering the torque generated by the crank wherein a converter unit for converting the angular displacement into a change in magnetic flux and that a magnetic field-sensitive sensor for detecting the angular displacement is provided, characterized by, that the converter unit comprises at least one magnet (15) and two mutually rotatable magnetic guide elements (21, 22) which, within an air gap (25), change the shape of the air gap (25) depending on the angle by means of their shape and their relative angular position, wherein the magnetic field-sensitive sensor, in particular a Hall sensor (19) or the like, is provided to detect changes in a magnetic flux, and wherein the magnet is a ring magnet (15) arranged concentrically to the crankshaft (5), such that an outer return circuit (17) of the magnetic flux runs around the outer circumference of the ring magnet (15) and an inner return circuit (18) of the magnetic flux runs around the inner circumference of the ring magnet (15), wherein the angle-dependent changing area of ​​the air gap (25) is located in the area of ​​the outer return circuit (17) and the magnetic field-sensitive sensor (19) is located in the area of ​​the inner return circuit (18) or vice versa. [2] Crank gear according to claim 1, characterized by , that the coupling unit (10) comprises a torsion element (10). [3] Crank gear according to one of the aforementioned claims, characterized by , that the torsion element (10) is arranged in a cavity (9) of the crankshaft (5). [4] Crank gear according to one of the preceding claims, characterized by, that the torsion element (10) is connected to the gear wheel (1) at a connection point in the discharge area (12) by means of a connecting element (8) in a rotationally fixed manner, wherein the connecting element (8) extends from the cavity (9) of the crankshaft (5) through a passage (13) in the wall of the crankshaft (5) and that the torsion element (10) is connected to the crankshaft (5) at a connection point in the receiving area (11) in a rotationally fixed manner. [5] Crank gear according to one of the preceding claims, characterized by , that the torsion element (10) is deformable against a restoring torque in such a way that the angular offset between the receiving area (11) and the delivery area (12) is torque-dependent. [6] Crank gear according to one of the preceding claims, characterized by , that the torsion element is a torsion rod(10). [7] Crank gear according to one of the preceding claims, characterized by, that one guide element (21) has a toothed inner circumference (23) and the other guide element (22) has a toothed outer circumference (24), so that the shape of the air gap (25) depends on the angular position of the teeth. [8] Crank gear according to one of the preceding claims, characterized by , that the magnetic field-sensitive sensor (19) is arranged at a distance from the guide elements (21,22). [9] Crank gear according to one of the aforementioned claims, characterized by that an evaluation unit is provided for determining the torque based on the detected sensor signal.

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