Crank transmission with a crankshaft for connection to at least one foot-operated or hand-operated crank

Abstract

A crank transmission having a crankshaft for connection to at least one foot or hand crank and at least one gear wheel driven by means of the crankshaft (5) is proposed. A coupling unit is provided between the crankshaft and the gear wheel. Under load, the coupling unit has at least temporarily an angular offset between a crank-side receiving region and an output region connected to the gear wheel for receiving and outputting the torque generated via the crank.

Claims

1. A transmission, comprising: a shaft, and at least one wheel driven by means of the shaft, wherein a coupling unit is provided between the shaft and the wheel, wherein the coupling unit under load at least temporarily has an angular offset between a crank-side receiving region and an output region connected to the wheel for receiving and outputting the torque introduced into the shaft, wherein a transducer unit is provided for converting the angular offset into a change in a magnetic flux, and wherein a magnetic field-sensitive sensor is provided for detecting the angular offset, wherein the transducer unit comprises at least one magnet and two magnetic guide elements that can be rotated with respect to each other, wherein the guide elements, within an air gap, change the shape of the air gap in an angle-dependent manner by their shape and their relative angular position, wherein the coupling unit comprises a torsion element, wherein the torsion element is connected in a rotationally fixed manner to the at least one wheel at a connection point in the output region by means of a connecting element, wherein the connecting element extends from a cavity of the shaft through a passage in a wall of the shaft, and wherein the torsion element is connected in a rotationally fixed manner to the shaft at a connection point in the receiving region.

2. The transmission of claim 1, wherein the torsion element is disposed in a cavity of the shaft.

3. The transmission of claim 1, wherein the torsion element is deformable in a torque-dependent manner against a restoring torque in such a way that the angular offset between the receiving region and the output region results in a torque-dependent manner.

4. The transmission of claim 1, wherein the torsion element is a torsion bar.

5. The transmission of claim 1, wherein one of the guide elements has a toothed inner circumference and the other of the guide elements has a toothed outer circumference, such that the shape of the air gap depends on the angular position of teeth of the toothed inner circumference and of the toothed outer circumference.

6. The transmission of claim 1, wherein the magnetic field-sensitive sensor is provided to detect changes in the magnetic flux, and wherein the magnetic field-sensitive sensor is spaced apart from the guide elements.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) An embodiment of the disclosure is shown in the drawing and is explained in more detail below with reference to the figures.

(2) In detail, there is shown in

(3) FIG. 1 a longitudinal section through various transmission components and the sensor system for the torque of a transmission,

(4) FIG. 2 a top view of two guide elements rotatable relative to each other in a first angular position,

(5) FIG. 3 a top view of two guide elements rotatable relative to each other in a second angular position, and

(6) FIG. 4 a perspective view of the crankshaft with a connecting pin as a drive element.

EMBODIMENTS

(7) FIG. 1 shows the main components of a transmission. Specifically, these include various transmission gear wheels (1, 2, 3, 4), of which the first transmission gear wheel (1) is driven by a crankshaft (5).

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

(9) FIG. 1 further shows the inner cavity (9) of the crankshaft (5), in which a torsion bar (10) is arranged. The torsion bar is non-rotatably connected to the crankshaft at its crank-side receiving region (11), for example pressed or welded or shrunk on. At its opposite output region (12), the torsion bar (10) is connected to the gear wheel (1) in a rotationally fixed manner 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 formed as an oblong hole (see FIG. 4), the edge (14) of which forms a mechanical end stop for the rotation of the connecting pin in the passage (13).

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

(11) A Hall sensor (19) is arranged in the area of the inner return circuit. An annular space (20) is arranged outside the Hall sensor (19) for the arrangement of the guide elements not shown in FIG. 1, and extends far into the area of the outer return circuit (18).

(12) FIGS. 2 and 3 show 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 inner toothing (23) and an outer toothing (24), respectively, which project into an air gap (25) of the outer return circuit.

(13) The toothings (23, 24) form the contours of the air gap (25), whereby the shape of the outer air gap (25) can be changed by relatively rotating the guide elements (21, 22). FIGS. 2 and 3 show two different angular positions of the guide elements (21, 22) relative to each other. The toothings (23, 24) and the air gap (25) are located in the area of the outer return circuit (17). However, by relatively rotating the guide elements (21, 22), the flux of the magnetic field in the inner return circuit (18) and thus also in the inner air gap (26) is also changed and can thus be detected by sensorically via the Hall sensor (19), wherein FIGS. 2 and 3 illustrate the use of several Hall sensors.

(14) Since the magnetic field of the inner air gap (26) is homogeneous at a constant overlap of the guide elements (21, 22) of the outer return circuit, the sensor signal remains constant during rotation of the shaft. By changing the overlap of the guide elements of the outer return circuits, the magnetic field in the inner air gap (26) can be varied. If more magnetic flux flows through the outer return circuit due to greater overlap of the guide elements, less magnetic flux consequently flows through the inner return circuit and thus also through the inner air gap (26). If the overlap of the guide elements is reduced, this is correspondingly reversed.

(15) The inner guide element (22) is connected to the crankshaft, and the outer guide element (21) is connected to the gear wheel (1), in a rotationally fixed manner. 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 the at least one Hall sensor (19) thus form a transducer unit.

(16) The arrangement described is capable of converting a torque introduced by physical force of a person by means of a crank onto the crankshaft (5) into an angular offset that can be detected sensorically. For this purpose, the torsion bar as a torsion element (10) receives the torque and twists under the corresponding load. This can be the case because the transmission initially opposes the torque, for example by means of a drive wheel to be driven via the transmission. This results in an angular offset over the extension of the torsion bar (10) and thus between the receiving region (11) and the output region (12).

(17) Since the torsion bar (10) is non-rotatably connected there 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).

LIST OF REFERENCE SIGNS

(18) 1 gear wheel 2 gear wheel 3 gear wheel 4 gear wheel 5 crankshaft 6 toothing 7 toothing 8 connecting pin 9 cavity 10 torsion bar 11 receiving region 12 output region 13 passage 14 edge 15 ring magnet 16 recess 17 return circuit 18 return circuit 19 Hall sensor 20 annular space 21 guide element 22 guide element 23 inner toothing 24 outer toothing 25 air gap 26 air gap