Sensor assembly for the drivetrain of a bicycle, holding element, and bicycle

Abstract

The invention relates to a sensor assembly for the drivetrain of a bicycle, wherein the sensor assembly has a printed circuit board (18), at least one torque sensor (16), a rotary element (10) of the drive train, and a holding element (20). The torque sensor (16) is secured to the rotary element (10) and is designed to detect a torque transmitted via the rotary element (10), and the printed circuit board (18) is connected to the torque sensor (16) in order to process sensor signals. The printed circuit board (18) is secured to the rotary element (10) via the holding element (20), and the holding element (20) seals an end face of the printed circuit board (18) facing the rotary element (10) on the rotary element (10). The invention additionally relates to a holding element (20) and to a bicycle.

Description

[0001] ZF Friedrichshafen AG Friedrichshafen

[0002] Sensor arrangement for a drive train of a bicycle, holding element and bicycle

[0003] Technical area

[0004] The present invention relates to a sensor assembly for a drivetrain of a bicycle. Furthermore, the present invention relates to a holding element for such a sensor assembly and to a bicycle.

[0005] State of the art

[0006] In a bicycle's drive train, it can be useful to record the torque introduced there. For example, a rider can drive a crankshaft using the respective pedals. The torque introduced and transmitted in this way is then used, for example, to power the bicycle. The torque recording is used, for example, to control a gear shift and, alternatively or additionally, an electric motor to assist the rider. The transmitted torque is recorded, for example, at a rotating element such as a shaft or a gear. For this to happen, however, the respective sensors must be attached to this rotating element. A circuit board is also required to process the respective sensor signals. The processed sensor signals are then transmitted from the circuit board, for example wirelessly via coils. This circuit board is also usually attached to the rotating element.The respective electronic components must be protected from environmental influences such as chips, dirt, moisture, and oil. Seals are provided accordingly. Contact between the electronic components and other components, such as the rotating element, is also generally avoided. Otherwise, vibrations from these parts, for example, can easily damage the electronic components. Accordingly, spacers and, alternatively or additionally, damping elements are required.

[0007] This results in a large number of parts, which can be very costly. These parts require complex alignment and assembly. Alignment can be done either laboriously manually or using additional centering parts. Assembly involves numerous individual steps. Furthermore, the dimensions and materials, as well as the respective tolerances of these parts, must be matched to one another to allow, for example, thermal expansion without damage. This makes structural design difficult, and the high tolerances sometimes required can further increase production costs.

[0008] Description of the invention

[0009] The object of the present invention is to enable cost-effective torque detection in bicycle drivetrains. This object is achieved by the subject matter of the independent patent claims.

[0010] A first aspect relates to a sensor arrangement for a drive train of a bicycle. The bicycle can be designed, for example, as a mountain bike, touring bike, or racing bike. The bicycle can have an electric motor. The bicycle can be designed, for example, as a pedelec. The drive train can have a transmission. The drive train can be designed to transmit torque to an output of the bicycle. For example, torque can be introduced into the transmission by the electric motor and, alternatively or additionally, by a rider of the bicycle. For example, an input shaft of the drive train can be designed as a pedal crankshaft.

[0011] The sensor arrangement comprises a rotating element of the drive train. The rotating element can be designed, for example, as a shaft, connecting part, or gear of the transmission. For example, the rotating element can be a part that connects the pedal crankshaft to the transmission. The rotating element can, for example, be permanently connected to the pedal crankshaft in a rotationally fixed manner or connectable in a rotationally fixed manner, for example via a gearing or a freewheel. The rotating element can, for example, be permanently connected to an input shaft of the transmission in a rotationally fixed manner or connectable in a rotationally fixed manner. The rotating element can provide a connection between the pedal crankshaft and the transmission for torque transmission. The rotating element can, for example, be rotatably mounted on a frame of the bicycle. The rotating element can, for example, be designed as a pot. The rotating element can have an axis of rotation. The rotating element can be rotationally symmetrical to its axis of rotation.

[0012] The sensor arrangement comprises at least one torque sensor. The torque sensor is attached to the rotating element. For example, the torque sensor can be glued or screwed to the rotating element. The torque sensor is designed to detect a torque transmitted via the rotating element. For example, the torque sensor can measure a deformation of the rotating element. This can be used to determine the transmitted torque. The torque sensor can be designed, for example, as a strain gauge.

[0013] The sensor arrangement can comprise a plurality of torque sensors. The torque sensors can, for example, be mounted on the rotating element at equal spacing and on the same radius. Using multiple torque sensors, each designed as a strain gauge, for example, can improve the accuracy of torque detection and, alternatively or additionally, obtain additional information from the measurements, such as pedal position. The following statements for a torque sensor can equally apply to several or all torque sensors, where applicable. Therefore, the following refers only to the torque sensor.

[0014] The sensor arrangement comprises a printed circuit board. The printed circuit board is connected to the torque sensor for sensor signal processing. For example, respective electrical connections can be provided between the torque sensor and the printed circuit board. The connections can be provided, for example, by bonding or cables. The connection can also comprise further parts. A printed circuit board can, for example, be designed as a printed circuit board. The printed circuit board can have a carrier substrate and conductive traces. The conductive traces can, for example, be applied to the carrier substrate or etched into the carrier substrate. The printed circuit board can, for example, have only one side on which conductive traces are provided. An opposite side can be electrically insulating. The printed circuit board can be designed to be completely closed.Electronic components such as resistors, transistors, and microprocessors can be arranged on the circuit board. The electronic components can form part of the circuit board. The sensor signal processing can include signal evaluation. For example, the measurement signals from multiple strain sensors can be merged. For example, the measurement signals can be transformed, for example from an analog measurement signal to a digital signal. For example, the currently transmitted torque can also be determined based on the measurement signals. The sensor signal processing can also include signal transmission. For example, the circuit board can have coils to wirelessly transmit the respective signals to a stationary component. For example, the respective recorded information can be transmitted to a control device or evaluation device on the bicycle.

[0015] The sensor assembly has a holding element. The holding element is designed to secure the circuit board to the rotating element. The circuit board is thus secured to the rotating element via the holding element. The circuit board can be held at a distance from the rotating element by the holding element.

[0016] For example, no part of the circuit board touches the rotating element. The holding element can be arranged axially between the circuit board and the rotating element. The axial direction can be defined by the rotational axis of the rotating element. The rotating element can have an axis of symmetry that corresponds to its rotational axis. The circuit board can rotate with the rotating element.

[0017] The holding element seals an end face of the circuit board facing the rotating element to the rotating element. This end face of the circuit board can point axially in the direction of the rotating element. The holding element can seal a gap between the circuit board and the rotating element. For example, the entire end face facing the rotating element or only a portion of it can be sealed. For example, the electronic components can be housed within the sealed space. For example, conductor tracks can be arranged only on the side facing the rotating element and alternatively or additionally only in sealed areas. This provides simple protection for the sensor arrangement from environmental influences. For example, the circuit board can be arranged in an oil chamber of the drive train and thus protected from oil and contamination.For example, a separate or additional sealing element for the circuit board may not be necessary. The sensor assembly may include a holder and a seal for the circuit board, which, for example, is formed integrally from the holding element.

[0018] The holding element can provide vibration isolation for the circuit board from the rotating element. The holding element can function as a damping element. The holding element can, for example, be designed as an injection-molded component. The holding element can, for example, be made of a soft thermoplastic or a thermoplastic elastomer. Due to the end-face arrangement, the circuit board can be supported over a large area by the holding element, whereby elastic influences during holding can be minimal. For example, the circuit board can rest on the holding element with its end face. For example, the holding element can rest on the rotating element with its end face facing away from the circuit board and thus facing the rotating element.

[0019] The sensor arrangement can thus have few components. Assembly can also be cost-effective and simple. For example, no additional assembly step may be necessary besides attaching the circuit board for sealing. The holding element can be designed as a single monolithic component. The holding element is, for example, permanently or detachably connected to the circuit board. The holding element is, for example, permanently or detachably connected to the circuit board. With a permanent connection, assembly can be simple and cost-effective. With a detachable connection, maintenance and even replacement of individual components can be easy.

[0020] In one embodiment of the sensor arrangement, it is provided that the holding element is designed to center the circuit board on the rotating element. For example, the circuit board and the rotating element can be arranged coaxially to one another. For example, the circuit board and the rotating element can be arranged concentrically. For example, an axis of symmetry of the circuit board can be coaxial to the axis of rotation of the rotating element. This can minimize imbalances caused by the circuit board or prevent them entirely. By centering by the holding element, alignment during fastening of the circuit board can take place automatically. For example, the circuit board can be held by the holding element only in one or more predetermined positions on the rotating element. In this way, a defined mounting orientation can be easily specified.This means that no manual alignment is required during assembly and no additional components are required for alignment.

[0021] In one embodiment of the sensor arrangement, the holding element has at least one circuit board centering pin that engages with a recess in the circuit board. For example, the circuit board can have a recess or through-opening in which the circuit board centering pin is arranged. The circuit board centering pin can, for example, be a pin that projects axially in the direction of the circuit board and is formed, for example, on an end face of the holding element. The holding element can also have a plurality of circuit board centering pins, for example two, three, or more circuit board centering pins. These can, for example, be evenly spaced in the circumferential direction. This allows for very uniform holding. Such a design can be very useful with multiple torque sensors if a relative angular orientation of the circuit board with respect to the torque sensors is irrelevant.For example, the circuit board can be connected to three torque sensors at three points, and it may be irrelevant which of the three torque sensors is connected to which of these three points on the circuit board. If a clear alignment with exactly one angular position is required, the circuit board centering pins can also be arranged unevenly on the holding element. In this case, assembly is only possible with one orientation, for example. If the circuit board centering pins extend through the circuit board, the holding element can form a seal with the circuit board there, for example using the circuit board centering pins. The circuit board centering pins can, for example, seal off the respective through-holes in the circuit board.

[0022] In one embodiment of the sensor arrangement, it is provided that the

[0023] The holding element has at least one rotary element centering pin which engages with a recess in the rotary element. For example, the rotary element can have a recess or through-opening in which the rotary element centering pin is arranged. The rotary element centering pin can, for example, be a pin which projects axially in the direction of the rotary element and which is formed, for example, on an end face of the holding element. The holding element can also have a plurality of rotary element centering pins, for example two, three or more rotary element centering pins. These can, for example, be evenly spaced in the circumferential direction. This makes it possible to achieve uniform holding. Such a design can be useful with multiple torque sensors if a relative angular orientation of the circuit board with respect to the torque sensors is irrelevant.For example, the circuit board can be connected to three torque sensors at three points, and it may be irrelevant which of the three torque sensors is connected to which of the three points on the circuit board. If a clear alignment with exactly one angular position is required, the rotary element centering pins can also be arranged unevenly on the holding element. In this case, assembly is only possible with one alignment, for example. If the rotary element centering pins extend through the rotary element, the rotary element centering pins can seal with the rotary element. If the rotary element centering pins extend through the rotary element, the holding element can seal with the rotary element at that point, for example using the rotary element centering pins. The rotary element centering pins can, for example, seal off the respective through-openings in the rotary element.

[0024] The circuit board centering pin and the rotary element centering pin can be arranged coaxially with each other. If multiple circuit board centering pins and rotary element centering pins are provided, they can be arranged coaxially with each other in pairs. This allows a connecting area of ​​the centering pins or the holding element to be reinforced centrally for each pair, making the holding element light and robust. Furthermore, fastening can be carried out on both sides simultaneously, for example by stamping both sides of the holding element. This can make assembly quick and cost-effective. For example, all centering pins can have the same diameter and length. In one embodiment of the sensor arrangement, it is provided that the respective centering pins are hot-stamped for fastening to the engaged component.The centering pins can be the respective circuit board centering pins and alternatively or additionally the respective rotary element centering pins. The engaged component can be the circuit board or the rotary element, depending on the centering pin. By hot stamping the centering pins, the holding element can be permanently connected to the circuit board or the rotary element without the need for additional fixation, for example by screws, rivets, or adhesive. Hot stamping can seal respective through-holes with the centering pins. Alternatively, the holding element can also be connected to the rotary element and alternatively or additionally to the circuit board in another way, for example by screwing or gluing. During hot stamping, a hot tool head can spread a protruding part of a centering pin and press it onto the circuit board or the rotary element.In this process, a protruding end portion of the centering pin expands, allowing a diameter larger than that of the through hole in which the centering pin is located. This allows for a fastening similar to a rivet.

[0025] In one embodiment of the sensor arrangement, the circuit board is provided with a ring-shaped basic shape. The basic shape can, for example, be a shape along the axis of rotation. This can prevent imbalances. The circuit board can, for example, have a central axial through-hole. An element of the drive train, such as the crankshaft, can extend through the through-hole.

[0026] In one embodiment of the sensor arrangement, the retaining element has a basic annular shape. This allows for the avoidance of imbalances. The retaining element can, for example, have a central axial through-hole. An element of the drive train, such as the crankshaft, can extend through the through-hole.

[0027] In general, the holding element and the circuit board can have corresponding basic shapes. For example, the circuit board and the holding element can have the same shape along the rotation axis. This can prevent overhang and achieve uniform support and stability. For example, the holding element and the circuit board can also have a circular or rectangular basic shape.

[0028] In one embodiment of the sensor arrangement, the holding element comprises a radially outer ring, a radially inner ring, and at least one radial strut extending therebetween, which connects the radially outer ring and the radially inner ring. For example, one of the centering pins can be arranged on the radial strut. For each pair of circuit board centering pin and rotary element centering pin, one radial strut can be provided, with this pair of circuit board centering pin and rotary element centering pin being arranged on this radial strut. For example, the circuit board centering pin can protrude from one end face of the radial strut, and the rotary element centering pin can protrude from an opposite end face of the radial strut. The circuit board and, alternatively or additionally, a contact element for connecting a torque sensor can be arranged adjacent to the radial strut.This can result in a particularly light holding element.

[0029] In one embodiment of the sensor arrangement, the holding element has a radially inner, axially protruding first sealing lip and a radially outer, axially protruding second sealing lip. For example, the first sealing lip can be formed on the radially inner ring of the holding element. For example, the second sealing lip can be formed on the radially outer ring of the holding element. The first sealing lip and the second sealing lip can rest on the end face of the circuit board facing the rotating element. As a result, the circuit board can be axially supported by the sealing lips and can also be well sealed. In addition, the fastening of the circuit board to the rotating element or with the holding element, for example by hot-stamping the centering pins, can press the circuit board against the first and second sealing lips and thus provide a particularly good seal.Alternatively or additionally, the retaining element can have a radially inner, axially protruding sealing lip and a radially outer, axially protruding sealing lip, which protrude axially opposite to the previously described sealing lips. These sealing lips can abut and seal against the end face of the rotating element facing the circuit board.

[0030] In one embodiment of the sensor arrangement, it is provided that the holding element has a radially inner, axially protruding third sealing lip. Alternatively or additionally, the holding element can have a radially outer, axially protruding fourth sealing lip. In addition, the holding element can have the sealing lips described above or can be free of additional sealing lips. The third sealing lip can bear against a radially inner circumferential side of the circuit board. The fourth sealing lip can bear against a radially outer circumferential side of the circuit board. In this way, the circuit board can optionally be radially enclosed and thus additionally or exclusively centered. In addition, an additional seal can be provided in this way. Alternatively or additionally, the holding element can have a radially inner, axially protruding sealing lip which bears against a radially inner circumferential side of the rotary element.Alternatively or additionally, the retaining element can have a radially outer, axially protruding sealing lip that bears against a radially inner circumferential side of the rotating element. These sealing lips can thus protrude axially opposite to the previously described third and fourth sealing lips and thus in the direction of the rotating element. This allows the retaining element to radially enclose the rotating element and thus be additionally or exclusively centered.

[0031] In one embodiment of the sensor arrangement, it is provided that the holding element forms an assembly aid which guides the circuit board when correctly positioned on the holding element. Alternatively or additionally, the holding element can form an assembly aid which guides the holding element when correctly positioned on the rotating element. The assembly aid can be formed, for example, by respective sealing lips. The sealing lips can be tapered at an end facing the element to be inserted. This can make insertion easier. For example, the assembly aid is formed by the third sealing lip and the fourth sealing lip. The circuit board can then be inserted into the holding element at its end, with a receptacle radially delimited by the third and fourth sealing lips initially having a larger diameter than the circuit board. This makes insertion easy.At their base, the sealing lips spread out and then force the circuit board into a predefined and sealing position.

[0032] In one embodiment of the sensor arrangement, it is provided that the torque sensor is arranged in a sealed manner on the rotating element. The seal can also at least partially seal a connection between the torque sensor and the circuit board. For example, the torque sensor can be enclosed between the rotating element, the holding element, the circuit board and, alternatively or additionally, an associated seal. For example, the torque sensor can be cast onto the rotating element and thus enclosed between the casting compound and the rotating element. For example, a cover can be arranged on the circuit board or the holding element and the strain sensor can be enclosed between the rotating element, the cover and, optionally, the circuit board and, alternatively or additionally, the holding element.The cover can have a cover element, which is designed, for example, as an overmolded sealing cap that is alternatively or additionally connected to a film hinge. The cover element can also be clipped onto the circuit board, for example. This way, the torque sensor and, alternatively or additionally, its connection to the circuit board can be protected without requiring numerous additional components and assembly steps.

[0033] In one embodiment of the sensor arrangement, it is provided that the holding element is designed to support a contact element of the torque sensor with the circuit board during production of the connection between the torque sensor and the circuit board. For example, the torque sensor can be radially enclosed by a section of the holding element. The contact element can, for example, be a contact circuit board which is arranged beneath the circuit board in the direction of the rotating element. This contact circuit board is then supported by this enclosure and rests on the holding element during connection. In this way, for example, the connection can be produced simply and reliably using a bonding process. The contact element can, for example, also be a cable which is soldered on and held in position by pressing against the holding element.

[0034] The holding element can form a carrier for the circuit board, which combines sealing, spacers, support and positioning aids in one component.

[0035] A second aspect relates to a holding element for a sensor arrangement of a bicycle drive train. The holding element can be designed as a holding element of the sensor arrangement according to the first aspect. Further features, embodiments, and advantages can be found in the descriptions of the first aspect. Conversely, features, embodiments, and advantages of the second aspect also represent features, embodiments, and advantages of the first aspect.

[0036] The holding element is designed to attach a circuit board for signal processing of a torque sensor to a rotating element of the drive train, to which the torque sensor is attached for detecting a torque transmitted via the rotating element. The holding element is also designed to seal an end face of the circuit board facing the rotating element to the rotating element.

[0037] A third aspect relates to a bicycle. The bicycle has a drivetrain. The drivetrain can be configured to transmit torque from a rider and, alternatively or additionally, an electric motor to an output. The drivetrain can, for example, include a transmission, a pedal crankshaft, the output, and also the electric motor.

[0038] The bicycle has the holding element according to the second aspect and, alternatively or additionally, the sensor arrangement according to the first aspect. This allows a torque transmitted to the rotating element of the drive train, which torque is generated, for example, by the rider and, alternatively or additionally, by the electric motor, to be detected. Further features, embodiments, and advantages can be found in the descriptions of the first and second aspects. Conversely, features, embodiments, and advantages of the third aspect also represent features, embodiments, and advantages of the first and second aspects, respectively.

[0039] Short description of the characters

[0040] Fig. 1 shows a schematic perspective view of a sensor arrangement with a circuit board, a rotating element and a holding element for a drive train of a bicycle.

[0041] Fig. 2 shows a schematic perspective view of the holding element from a side facing the rotating element.

[0042] Fig. 3 shows a schematic perspective view of the holding element from an opposite side, which is facing the circuit board.

[0043] Fig. 4 shows a schematic sectional perspective view of the sensor arrangement according to Fig. 1 .

[0044] Fig. 5 shows a schematic sectional side view of the sensor arrangement according to Fig. 1.

[0045] Detailed description of the characters

[0046] Fig. 1 shows a schematic perspective view of a sensor arrangement of a bicycle drive train. The sensor arrangement has a rotating element 10, which is designed as a rotationally symmetrical pot. A pedal crankshaft 12 of the drive train is permanently attached to the rotating element 10 in a rotationally fixed manner. The rotating element 10 has a toothing 14, with which the rotating element 10 is permanently connected in a rotationally fixed manner to an input shaft of a transmission of the drive train. The rotating element 10 can rotate about its axis of symmetry and thus its longitudinal axis. A rider can use the rotating element 10 to transmit torque to the transmission and thus an output of the drive train. The sensor arrangement has three torque sensors 16, which are evenly spaced in the circumferential direction and arranged at the same radial distance from the axis of rotation and are attached to the rotating element 10. The torque sensors 16 are designed as strain gauges.The torque transmitted to the rotating element 10 reversibly deforms the rotating element 10, and this deformation is detected by the torque sensors 16. This allows conclusions to be drawn about the transmitted torque.

[0047] The sensor arrangement comprises a circuit board 18. The circuit board 18 is arranged concentrically to the rotating element 10 and has a basic annular shape. The circuit board 18 comprises a substrate which is free of conductive tracks on an end side facing away from the rotating element 10 and is electrically insulating. On an end side facing the rotating element 10, conductive tracks are etched into the circuit board 18. Electronic components are also arranged there. The circuit board 18 is electrically connected to the torque sensors 16 and is designed to process the respective sensor signals from the torque sensors 16. The circuit board 18 wirelessly transmits the processed sensor signals to a stationary component of the bicycle.

[0048] The circuit board 18 is attached to the rotating element 10 via a holding element 20 of the sensor assembly. The holding element 20 is designed as a monolithic injection-molded component. The holding element 20 holds the circuit board 18 at a distance from the rotating element 10. The circuit board 18 is thus free from direct contact with the rotating element 10. Furthermore, the holding element 20 dampens vibrations. For this purpose, the holding element 18 is made of an elastic material, here a soft thermoplastic or a thermoplastic elastomer.

[0049] The holding element 20 also forms a gap between the rotating element 10 and the printed circuit board 18. The gap is axially delimited on one side by the rotating element 10 and axially delimited on an opposite side by the printed circuit board 18. The holding element 20 delimits the gap in the radial direction and thus seals the end face of the printed circuit board 18 facing the rotating element 10. The conductor tracks and electronic components are thus protected from damage, in this case, for example, from gear chips in a transmission oil.

[0050] The design of the holding element 20 can be seen in detail in Fig. 2 and Fig. 3. The holding element 20 has a radially outer ring 22, a radially inner ring 24 and three radial struts 26 extending therebetween, which connect the radially outer ring 22 and the radially inner ring 24. A basic shape of the holding element 20 is annular and corresponds to the circuit board 18. In addition, the holding element 20 has three borders 30, which are arranged radially between the radially outer ring 22 and the radially inner ring 24 and are connected to the radially outer ring 22. These borders 30 each radially surround one of the torque sensors 16 and thus delimit them from the sealed space for the conductor tracks and the electronic components.

[0051] Fig. 2 shows an end face of the retaining element 20 facing the rotating element 10. This end face is flat and thus seals by contacting the rotating element 10 over a large area. In another embodiment, the retaining element 20 has sealing lips, as on the end face facing the circuit board 18, which will be described below.

[0052] Fig. 3 shows the end face of the holding element 20 facing the circuit board 18. This end face of the holding element 20 has a first sealing lip 40, a second sealing lip 42, a third sealing lip 44, and a fourth sealing lip 46. Each of the four sealing lips 40, 42, 44, 46 is annular and projects axially toward the circuit board 18 and thus axially in a direction opposite to the rotating element 10. In one embodiment, the third sealing lip 44 is interrupted in the region of the borders 30, or in another embodiment, it follows the border 30. The four sealing lips 40, 42, 44, 46 can also be seen particularly well in the sectional view of Fig. 5.

[0053] The first sealing lip 40 is formed on the radially inner ring 24 and, as described in one embodiment, also on the border 30. The second sealing lip 42 is formed on the radially outer ring 22. The first sealing lip 40 and the second sealing lip 42 bear against the end face of the circuit board 18 facing the rotating element 10 and seal there. The third sealing lip 44 is formed on the radially inner ring 24. The third sealing lip 44 bears against a radially inner circumferential side of the circuit board 18 and additionally seals there. The fourth sealing lip 46 is formed on the radially outer ring 22. The fourth sealing lip 46 bears against a radially outer circumferential side of the circuit board 18 and additionally seals there.

[0054] The third sealing lip 44 and the fourth sealing lip 46 form an assembly aid for the printed circuit board 18. For this purpose, the third sealing lip 44 and the fourth sealing lip 46 are designed to taper towards the rotating element 10 and thus towards an end facing away from the radial struts 26. Thus, a radial distance between the free end of the third sealing lip 44 and the fourth sealing lip 46 is greater than in a base region, which seals the radially inner and outer circumference of the assembled printed circuit board 18. This facilitates insertion of the printed circuit board 18 and pressing it against the holding element 20, and the printed circuit board 18 is guided along the holding element 20 when correctly positioned.

[0055] The holding element 20 is also designed to center the circuit board 18 on the rotating element 10. For this purpose, the holding element 20 has a circuit board centering pin 50 on each radial strut 26, which protrudes axially in the direction of the circuit board 18. In addition, the holding element 20 has a rotating element centering pin 52 on each radial strut 26, which protrudes axially in the direction of the rotating element 10. The rotating element centering pins 52 and the circuit board centering pins 50 are arranged in pairs coaxial with one another. Each of the circuit board centering pins 50 is arranged in a recess in the circuit board 18, which is designed as a corresponding through-opening, and engages the circuit board 18 there. Each of the rotating element centering pins 52 is arranged in a recess in the rotating element 10, which is designed as a corresponding through-opening, and engages the rotating element 10 there.For the circuit board 18, a coaxial alignment with the rotating element 10 is thus specified, in addition to the third sealing lip 44 and the fourth sealing lip 46. Furthermore, only three angular positions are possible for the circuit board 18 relative to the rotating element 10 and thus the torque sensors 16. This ensures a correctly centered alignment of the circuit board 18 without the need for manual alignment or additional components. The three torque sensors 16 can be correctly connected to the circuit board 18 in each of the three angular orientations.

[0056] The circuit board centering pins 50 are hot-stamped to secure the circuit board 18 to the holding element 20. This also seals the associated through-openings of the circuit board 18 in addition to the sealing provided by the radial struts 26. The rotary element centering pins 52 are hot-stamped to secure the rotary element 10 to the holding element 20. This also seals the associated through-openings of the rotary element 10 in addition to the sealing provided by the radial struts 26. The radial struts 26 have a radially circumferential groove around each of the rotary element centering pins 52. The radial struts 26 have a radially circumferential projection around each of the circuit board centering pins 50. This projection forms a plateau, which additionally supports the comparatively fragile circuit board 18 during hot-stamping. The groove facilitates the production of the centering pins 50, 52.The rotating element 10 is made of metal here, which means that additional support during hot stamping is largely dispensed with. A coaxial pair of centering pins 50, 52 is hot stamped simultaneously in the illustrated embodiment. In one embodiment, all centering pins 50, 52 are hot stamped simultaneously.

[0057] The torque sensors 16 are arranged in a sealed manner on the rotating element 10. In one embodiment, the torque sensors 16 are simply encapsulated. In another embodiment, the rotating element 10, one of the borders 30, the printed circuit board 18, and a cover element fastened to the printed circuit board 18, such as a clipped-in protective cap, define a further intermediate space for each torque sensor 16. Fig. 4 and Fig. 1 show recesses 58 in the printed circuit board 18 that are aligned with the torque sensors 16, into which the protective caps are clipped. This allows the printed circuit board 18, the holding element 20, the rotating element 10, and the torque sensors 16 to be mounted first. The printed circuit board 18 and the torque sensors 16 can then be electrically connected. The sealing of the torque sensors 16 and their electrical connection to the printed circuit board 18 can then take place.

[0058] In Fig. 5, a contact element 60 can also be seen, which forms part of an electrical connection between one of the torque sensors 16 and the circuit board 18. The contact element 60 is designed as a contact circuit board. The end face of the contact circuit board with etched-in conductor tracks faces the circuit board 18 and is thus aligned opposite to the circuit board 18. The conductor tracks of the contact circuit board and the circuit board 18 are thus electrically contacted. The torque sensor 16 is electrically connected to the contact circuit board by a bonding process. During this production of the connection between the torque sensor 16 and the circuit board 18, a pressure of in the perspective of Fig. 4 and thus in the direction of the rotating element 10 is exerted on the contact element 60. The holding element 20 supports the contact element 60 with the border 30 on the underside orfrom the direction of the rotating element 10, allowing the bonding process to be carried out reliably. In one embodiment, the contact element 60 is attached to the circuit board 18, for example, by adhesive bonding. This attachment can be made, for example, before the circuit board 18 is mounted on the rotating element 10.

[0059] Reference symbol

[0060] 10 rotating element

[0061] 12 Crankshaft

[0062] 14 Gearing

[0063] 16 Torque sensor

[0064] 18 circuit board

[0065] 20 holding element

[0066] 22 radial outer ring

[0067] 24 radial inner ring

[0068] 26 Radial strut

[0069] 30 border

[0070] 40 first sealing flap

[0071] 42 second sealing lip

[0072] 44 third sealing lip

[0073] 46 fourth sealing lip

[0074] 50 PCB centering pins

[0075] 52 Rotary element centering pin

[0076] 58 recess

[0077] 60 contact element

Claims

Patent claims 1. Sensor arrangement for a drive train of a bicycle, wherein the sensor arrangement has a printed circuit board (18), at least one torque sensor (16), a rotary element (10) of the drive train and a holding element (20), wherein the torque sensor (16) is fastened to the rotary element (10) and is designed to detect a torque transmitted via the rotary element (10), wherein the printed circuit board (18) is connected to the torque sensor (16) for sensor signal processing, wherein the printed circuit board (18) is fastened to the rotary element (10) via the holding element (20), and wherein the holding element (20) seals an end face of the printed circuit board (18) facing the rotary element (10) on the rotary element (10).

2. Sensor arrangement according to claim 1, characterized in that the holding element (20) is designed to center the circuit board (18) on the rotating element (10).

3. Sensor arrangement according to claim 2, characterized in that the holding element (20) has at least one circuit board centering pin (50) which engages with a recess in the circuit board (18).

4. Sensor arrangement according to claim 2 or 3, characterized in that the holding element (20) has at least one rotary element centering pin (52) which engages with a recess in the rotary element (10).

5. Sensor arrangement according to claim 3 or 4, characterized in that respective centering pins (50, 52) are hot-stamped for fastening to the engaged component (18, 10).

6. Sensor arrangement according to one of the preceding claims, characterized in that the printed circuit board (18) has an annular basic shape and the holding element (20) has an annular basic shape.

7. Sensor arrangement according to one of the preceding claims, characterized in that the holding element (20) has a radially outer ring (22), a radially inner ring (24) and at least one radial strut (26) extending therebetween, which connects the radially outer ring (22) and the radially inner ring (24) 8. Sensor arrangement according to one of the preceding claims, characterized in that the holding element (20) has a radially inner axially projecting first sealing lip (40) and a radially outer axially projecting second sealing lip (42), wherein the first sealing lip (40) and the second sealing lip (42) bear against the end face of the printed circuit board (18) facing the rotating element (10).

9. Sensor arrangement according to one of the preceding claims, characterized in that the holding element (20) has a radially inner axially projecting third sealing lip (44) and a radially outer axially projecting fourth sealing lip (46), wherein the third sealing lip (44) bears against a radially inner circumferential side of the circuit board (18) and wherein the fourth sealing lip (46) bears against a radially outer circumferential side of the circuit board (18).

10. Sensor arrangement according to claim 9, characterized in that the holding element (20) forms an assembly aid which guides the circuit board (18) in a correct positioning on the holding element (20), wherein the assembly aid is formed by the third sealing lip (44) and the fourth sealing lip (46).

11. Sensor arrangement according to one of the preceding claims, characterized in that the torque sensor (16) is arranged in a sealed manner on the rotary element (10).

12. Sensor arrangement according to one of the preceding claims, characterized in that the holding element (20) is designed to support a contact element (60) of the torque sensor (16) with the circuit board (18) during the production of the connection of the torque sensor (16) with the circuit board (18).

13. Holding element (20) for a sensor arrangement of a drive train of a bicycle, wherein the holding element (20) is designed to fasten a printed circuit board (18) for signal processing of a torque sensor (16) to a rotary element (10) of the drive train, to which the torque sensor (16) is fastened for detecting a torque transmitted via the rotary element (16), wherein the holding element (20) is additionally designed to seal an end face of the printed circuit board (18) facing the rotary element (10) on the rotary element (10).

14. Bicycle with a drive train and with a sensor arrangement according to one of the preceding claims 1 to 12.

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