Rim magnet arrangement for securing a magnet to a rim by means of a valve stem

Description

State of the art

[0001] The invention relates to a rim magnet arrangement for fixing a magnet to a rim by means of a stem of a valve, comprising a magnet arranged in a housing.

[0002] The invention further relates to a rim assembly for a bicycle or the like, comprising a rim magnet assembly and a rim.

[0003] The invention further relates to a method for producing a rim magnet arrangement.

[0004] Although applicable to any rim, the present invention is explained with reference to bicycle rims.

[0005] To measure the speed of bicycles, it has become known to attach a pulse generator in the form of a magnet to a spoke and to detect the respective rotation of the magnet around the wheel using a magnetic field sensor located on a part of the bicycle frame. The speed of the bicycle can be determined based on the time difference between two consecutive rotations of the magnet and the tire circumference, as disclosed, for example, in DE 10 2017 212 924 A1.

[0006] Furthermore, reference is made to the documents EP 1 728 711 A1, DE 20 2016 003819 U1, EP 3 435 024 A1 and DE 10 2018 210754 A1. Disclosure of the invention

[0007] In one embodiment, the present invention provides a rim magnet assembly for attachment to a stem of a valve, comprising a magnet, a fixing device configured to fix the magnet to the shaft of the valve in the axial direction of the shaft, and an anti-rotation device configured to fix the magnet in the circumferential direction of the shaft.

[0008] In one embodiment, the present invention provides a rim assembly for a bicycle or the like, comprising a rim magnet assembly as described above and a rim, wherein the magnet is axially and rotationally fixed to the rim by means of the fixing device and the anti-rotation device.

[0009] In one embodiment, the present invention provides a method for manufacturing a rim magnet assembly as described above, wherein the housing is manufactured by means of a 2-component injection molding process.

[0010] One of the advantages achieved is the simple and reliable attachment of a magnet to a rim using the valve stem. Another advantage is that the magnet can be attached to a variety of different rims. Another advantage is the particularly reliable detection of the driving speed of a magnet attached to a rim using the rim magnet arrangement. The magnet can, in particular, be designed as a permanent magnet.

[0011] Further features, advantages and further embodiments of the invention are described below or will become apparent thereby.

[0012] According to the invention, the magnet is arranged in a housing, particularly made of plastic. The advantage of this is that the magnet is protected from environmental influences.

[0013] According to a further advantageous development of the invention, the fastening device comprises a screw device that can be screwed onto the valve stem. This allows for a reliable and detachable fastening of the magnet to a rim.

[0014] According to a further advantageous development of the invention, the housing has at least one spring-elastic element that protrudes from the housing in the axial direction of the shaft and, in particular, is partially tapered inward toward the center of the housing. This creates a preload in the axial direction, enabling particularly reliable attachment to the valve. If, for example, the tire pressure drops, the valve protrudes further from the rim. This can be compensated for by the preload. Furthermore, the at least one spring-elastic element can also provide an anti-twist feature by at least partially engaging the rim in a form-fitting manner.

[0015] According to a further advantageous development of the invention, at least two, in particular four, spring-elastic elements are arranged symmetrically on the housing and, in particular, are of identical design. This allows for a particularly high preload and a particularly secure anti-twist protection.

[0016] According to the invention, the anti-rotation device comprises a molded sleeve having at least one recess or projection, which engages with a corresponding projection or recess in the magnet and / or its housing. The molded sleeve is particularly designed to be self-locking. One of the advantages achieved is that it enables a simple yet reliable attachment of the magnet to the valve stem.

[0017] According to the invention, the anti-twist device is formed by an adhesive applied to the magnet and / or its housing, particularly in the form of a double-sided adhesive tape. This allows for particularly quick and easy attachment of the magnet to the valve stem.

[0018] According to the invention, the anti-rotation device comprises a clamp with a U-shaped cross-sectional profile, which can be secured to the shaft and is designed to prevent rotation when the magnet is secured by means of a positive connection with the magnet and / or with the housing on the one hand and at least partially with a rim on the other. One of the advantages achieved is that it enables easy attachment of the magnet to the rim. The U-shaped profile is understood in particular not only to mean a profile with right angles, but also a trough-shaped profile or the like.

[0019] According to a further advantageous development of the invention, the anti-rotation device comprises a bore in the magnet housing that is undersized relative to the shaft diameter. The advantage of this is that few components are required to secure the magnet.

[0020] According to the invention, the anti-rotation device comprises at least one friction-increasing element. This provides a particularly reliable anti-rotation device.

[0021] According to the invention, the anti-twist device comprises a compression sleeve arranged on the valve stem. The compression sleeve can preferably be made of rubber. The advantage of this is a simple anti-twist device provided by deformation. In this case, a sleeve can also be arranged together with the compression sleeve, particularly above it, on the valve stem.

[0022] According to the invention, the anti-rotation device is provided by the elastic material of the magnet housing. The advantage of this is anti-rotation protection without additional components. According to a further advantageous development of the invention, the magnet is formed in one piece, and the magnet and in particular the housing have a central, corresponding bore for attachment to the valve shaft. This allows the magnet and its housing to be easily plugged onto the shaft of the housing and secured by means of the securing device.

[0023] According to a further advantageous development of the invention, the magnet is constructed in two parts, and a receiving device for the two parts of the magnet is arranged in the housing. One of the advantages achieved is that it avoids the laborious and complicated process of securing a single magnet, particularly by means of a central bore.

[0024] According to a further advantageous development of the invention, the magnet is arranged such that it provides a magnetic field perpendicular to the axial direction of the valve stem or parallel to its axial direction. This ensures reliable detection of the magnet's magnetic field, particularly when the magnetic field is oriented perpendicular to the axial direction of the valve stem.

[0025] Further important features and advantages of the invention emerge from the subclaims, from the drawings and from the associated description of the figures with reference to the drawings.

[0026] It is understood that the features mentioned above and those to be explained below can be used not only in the combination specified in each case, but also in other combinations or on their own, without departing from the scope of the present invention.

[0027] Preferred embodiments and embodiments of the present invention are illustrated in the drawings and are explained in more detail in the following description, wherein the same reference numerals refer to the same or similar or functionally identical components or elements.

[0028] This shows Figure 1 shows a partial side view of a bicycle in the area of ​​the bicycle's drive; Figure 2a shows a rim magnet arrangement according to an embodiment of the present invention; Figure 2b shows a rim arrangement according to an embodiment of the present invention; Figure 3 shows a rim arrangement according to an embodiment of the present invention; Figure 4 shows a rim arrangement according to an embodiment of the present invention; Figure 5 shows a rim arrangement according to an embodiment of the present invention; Figure 6 shows a rim arrangement according to Figure 5in cross-section; Figures 7a, 7b, 7c each show a rim assembly according to an embodiment of the present invention; Figure 8 shows a rim magnet assembly according to an embodiment of the present invention; Figure 9 shows a rim assembly according to an embodiment of the present invention; Figure 10 shows a rim assembly according to an embodiment of the present invention; Figure 11 shows a rim assembly according to an embodiment of the present invention; and Figure 12 shows a rim assembly according to an embodiment of the present invention;

[0029] Figure 1 shows a partial side view of a bicycle in the area of ​​the bicycle's drive.

[0030] In Figure 1a bicycle 60 is shown in the area of ​​the drive 61. This has, in a known manner, a magnetic field sensor 62 integrated into the drive 61. Furthermore, a rim assembly 50 with rim magnet assembly 1 is shown, having a rim 8 which has a valve 3. The valve 3 has a valve stem 2, onto which a magnet 4 arranged in a housing 5 is placed. The housing 5 and magnet 4 have a central bore 20 for this purpose. The housing 5 rests on its underside on the rim 8 of the bicycle 60. Both are then secured to the stem 2 of the valve 3 by means of a mounting nut 10. The magnet 4 provides a magnetic field 200 which can be measured by the magnetic field sensor 62.

[0031] Figure 2a shows a rim magnet assembly according to an embodiment of the present invention.

[0032] In Figure 2aA rectangular magnet 4 is shown arranged in a substantially rectangular housing 5. To prevent the housing 5 from twisting during operation, the housing has a structural anti-twist protection. The anti-twist protection is formed here by flexible or elastic fins 11, which can adapt to the respective rim shape and are designed to protrude in the axial direction of the shaft 2 and partially project inward in the radial direction. A second function of the elastic fins 11 is to apply a preload, which then inhibits the mounting nut 10 and prevents the magnet 4 with the housing 5 from becoming loose during operation.

[0033] Figure 2b shows a rim assembly according to an embodiment of the present invention.

[0034] In Figure 2b, the magnet 4, including the housing 5, is shown mounted on the stem 2 of a valve 3 by means of a fixing device 6. For this purpose, the magnet 4 is first pushed over the valve 3, more precisely the stem 2 of the valve 3 in the axial direction 100 of the stem 2, until the flexible fins 11 touch the rim 8. The component, i.e. the magnet 4 and its housing 5, have an opening or bore 20 which has the diameter of the largest valve stem diameter to be covered, for example that of a Schrader valve. With a Presta valve, a compensating sleeve 22, as shown here, can be inserted between the stem 2 and the bore 20 of the component 4, 5. The valve nut 10 is then screwed onto the valve 3 until it rests on the compensating sleeve 22. Now the valve nut 10 presses the component onto the rim 8 via the compensating sleeve 22. The flexible fins 11 are pressed onto the flanks of the rim 8 and partially adapt to the shape of the rim 8.The valve nut 10 is now tightened further, particularly by hand. The valve nut 10 of the fastening device 6 now presses the compensating sleeve 22 onto the housing 5 of the magnet 4. Since the flexible fins 11 have a certain rigidity, this system is now preloaded. The principle corresponds to that of a leaf spring. The wider the rim 8 and the sharper the flank angle of the rim 8, the more preload force is generated, since the fins 11 are pressed further apart. An additional preload force can be specified in the design by designing the fins 11 to taper inwards towards the center of the component 4, 5 in the unloaded state, as shown in FIGS. Figures 2a and 2b shown.

[0035] This preload prevents the magnet 4 from rotating laterally in the circumferential direction 101 of the shaft 2. Since the preload force acts in particular between the valve nut 10 and component 4, 5, it also prevents the valve nut 10 from loosening at the frictional connection. Pressure fluctuations in the tire on the rim 8 in particular lead to a change in the preload force. For example, inflating the tire or tube causes the valve 3 to be pushed further out of the rim 8 and the preload force decreases. The preload force exerted by the fins 11 is so great that sufficient anti-twist protection and a sufficient inhibiting effect on the valve nut 10 is ensured even in the event of pressure fluctuations. The preload force required for the application can be adjusted by selecting the material with regard to elasticity and the material thickness of the fins 11 when designing the component 4, 5.Effective anti-twist protection is provided in particular by at least two fins 11, but there can also be more, for example four fins 11 as shown. When using tubeless valves, an O-ring is often used, which is inserted between the rim 8 and the valve nut 10. In order to be able to use the magnet 4 together with the housing 5 with tubeless valves, in a further embodiment (not shown here), a recessed groove can be formed on the rim-facing side of the component 4, 5 in the area of ​​the bore 20, which receives the O-ring. In this way, the underside of the component 4, 5 can continue to rest on the rim 8 without an air gap.

[0036] Figure 3 shows a rim assembly according to an embodiment of the present invention.

[0037] In Figure 3a rim arrangement 50 is shown. The anti-twist device 7 here comprises a shaped sleeve 12 which is screwed onto the shaft 2 of the valve 3. The valve 4 together with the housing 5 is pushed over it using the bore 20. The component 4, 5 is then tightly screwed on using the valve nut 10. The shaped sleeve 12 has a defined outer contour 13, the negative 14 of which is reproduced in the housing 5, in particular in the form of an overmolding 5 of the magnet 4, here a projection 13 and a corresponding recess 14. This allows the component 4, 5 to be fitted precisely. The shaped sleeve 12 is designed to be self-locking. This ensures that the magnet 4 together with the housing 5 is secured against twisting. The holding shape of the shaped sleeve 12 is also designed to simplify screwing onto the valve 3. One type of molded sleeve can be provided for both Presta and Schrader valves. Advantages of this design include: Component 4, 5 as a whole can be designed very simply and sleekly. The molded sleeve 12 can be manufactured as a simple injection-molded part. Component 4, 5 can be produced cost-effectively and easily in large quantities. Component 4, 5 can be used with almost all rim shapes.

[0038] Figure 4 shows a rim assembly according to an embodiment of the present invention.

[0039] In Figure 4 a rotation lock 7 of a rim arrangement 50 in the form of a double-sided adhesive tape 15 is now shown.

[0040] Before assembling the component 4, 5, a double-sided adhesive tape 15 is applied to the left and right of the central bore 20 on the side of the housing 5 of the magnet 4 facing the rim 8. The component 4, 5 is then placed onto the shaft 2 of the valve 3 and pressed onto the adhesive tape 15. The component 4, 5 is then firmly screwed in place using the valve nut 10. The adhesive tape 15 also prevents the component 4, 5, in particular the magnet 4, from lifting off the rim 8 if the valve nut 10 becomes loose due to pressure fluctuations in the tire.

[0041] Advantages of this embodiment can include: The magnet 4 and the component 4, 5 as a whole can be designed very simply and sleekly. Standard and therefore cost-effective double-sided adhesive tape can be used. The component 4, 5 can be produced cost-effectively and easily in large quantities. The component 4, 5 can be used with almost all rim shapes. High reliability is ensured because the component 4, 5 remains firmly attached to the rim even during pressure fluctuations.

[0042] Figure 5 shows a rim assembly according to an embodiment of the present invention and Figure 6 a rim arrangement according to Figure 5 in cross section.

[0043] In the Figures 5 and 6 a rim arrangement 50 is shown with an anti-twist device 7 in the form of a securing clip 16.

[0044] This locking clip 16, which is partially flexible, is placed onto the shaft 2 of the valve 3 via a bore 16a. The component 4, 5 with the central bore 20 is placed over this and pressed firmly against the rim 8. The component 4, 5 is then screwed tightly using the valve nut 10. The shape of the locking clip 16 is designed such that it does not adapt to the shape of the rim 8 or bend when applied to the rim 8 without load. Only when the locking clip 16 is subjected to a contact force is the locking clip 16 pushed apart and partially adapts to the shape of the rim 8. The material of the locking clip 16 is selected such that the locking clip 16 acts as a spring when pressed onto the rim 8.

[0045] This creates a preload force. The shape of the retaining clip 16 is reproduced as a negative mold in the housing 5 of the magnet 4, so that with the corresponding contact force, a positive connection 30 is provided between the retaining clip 16 and the housing 5. In conjunction with the generated preload force, this ensures an anti-twist lock 7. Furthermore, the described system is clamped against the valve nut 10, which ensures compensation of pressure fluctuations and prevents the valve nut 10 from loosening. By varying the shape or cross-sectional profile of the retaining clip 16, almost all known rim shapes can be reproduced.

[0046] Possible advantages of this embodiment are The magnet 4 and the component 4, 5 as a whole can be designed very simply and slimly. The securing clamp 16 can be easily adapted to different rim shapes. The securing clamp 16 can be used with almost all rim shapes. The component 4, 5 and thus the magnet 4 do not come loose from the rim 8 in the event of pressure fluctuations in the tire.

[0047] Figure 7a, 7b , 7c each shows a rim assembly according to an embodiment of the present invention.

[0048] In the Figures 7b and 7c In each case, a component 4, 5 is shown in the form of a monomagnet. The monomagnet 4, 5 comprises two components, a monolithic magnet block 4 and a plastic overmold 5. For mounting on the shaft 2 of a valve 3, the monomagnet 4, 5 has a hole or bore 20 in the center. Depending on the design of the evaluation algorithm, the monomagnet 4, 5 can be shaped both lengthwise and in Figure 7cshown with magnetic field direction 200, as well as in height, according to Figure 7b , i.e. perpendicular to Figure 7c shown direction - magnetic field direction 200 - polarized.

[0049] In Figure 7a a component 4, 5 is shown, wherein the magnet 4 is formed in two parts with two parts 4a, 4b. The two parts 4a, 4b are arranged such that they have a common magnetic field direction 200 - here perpendicular to the axis of the shaft 2 of the valve 3. In contrast to the embodiment of the Figure 9 the two parts 4a, 4b are directly overmolded with the overmold 5 and not separately in a holder as in Figure 9 arranged.

[0050] The overmolding 5 protects the magnet 4 from weather influences and excessive stress. To prevent the component 4, 5 from twisting during operation, it has an anti-twist device 7, which is formed by the overmolding 5 or by the housing 5 of the magnet 4. The anti-twist device 7 can be designed analogously to the embodiment of the Figures 2a, 2bby flexible or elastic fins 11, which adapt to the rim shape. A second function of the elastic fins 11 is, as already explained, to apply a preload that inhibits the valve nut 10 and prevents the component 4, 5 from coming loose during operation. The material of the overmolding 5 is selected in particular such that it has sufficient strength to absorb the forces of the valve nut 10 and, on the other hand, has sufficient flexibility so that the lateral fins 11 can adapt to any rim shape. A possible advantage of this embodiment is that the magnet 4 and the component 4, 5 as a whole can be designed to be very simple, slim, and unobtrusive.

[0051] Figure 8 shows a rim magnet arrangement according to an embodiment of the present invention and Figure 9 a rim assembly according to an embodiment of the present invention.

[0052] In Figure 8 a component 4, 5 is shown which has two identical individual magnets 4a, 4b, which are mounted in a common holder 21 within a housing 5, which is formed by overmolding the two magnets 4a, 4b, according to the embodiment of the Figures 2a and 2b The individual magnets 4a, 4b can serve as signal transmitters. Depending on the design of the evaluation algorithm, the individual magnets 4a, 4b can be arranged both lengthwise and in Figure 9 shown with magnetic field direction 200, as well as in height, i.e. perpendicular to the Figure 9 shown direction in the plane of the drawing of the Figure 9 be polarized. The holder or holding cage 21 has two functions. Firstly, it holds the individual magnets 4a, 4b in position during the overmolding process, and secondly, it absorbs the screwing forces and stabilizes the component 4, 5. The fins 11 represent the Figures 2a, 2b described preload force and anti-twist protection.

[0053] Possible advantages of this embodiment are More cost-effective design due to higher number of magnets More stable design

[0054] In the following embodiments, the anti-twist device 7 is realized by increasing the coefficient of friction between magnet 4 or housing 5 and rim 8.

[0055] Figure 10 shows a rim assembly according to an embodiment of the present invention.

[0056] In Figure 10A rim assembly 50 is shown, which is arranged between two adjacent spokes 90 of a wheel. One or more so-called "friction shims," ​​i.e., friction discs 17, are arranged between the housing underside of component 4, 5, or, if the magnet 4 does not have a housing, between the underside of the magnet 4 and the rim 8. These friction shims 17 are designed such that their diameter is adapted to Presta and Schrader valves and map the contact surface of the magnet 4 or its housing 5 in the immediate vicinity of the bore 20. The disc or discs 17 are placed over the shaft 2 of the valve 3. Subsequently, the component 4, 5 is placed over it, and then the valve nut 10 is screwed onto the shaft 2 of the valve 3 and tightened. This creates micro-positive locking between the friction disc 17 and the housing 5, and between the friction disc 17 and the rim 8.In this way, the coefficient of friction can be at least doubled and thus an anti-twist protection 7 is ensured.

[0057] Figure 11 shows a rim assembly according to an embodiment of the present invention.

[0058] In the Figure 11In the embodiment shown, the anti-twist device 7 is created by a rubber sleeve 23 which is compressed and thereby pressed between the valve thread and the wall of the bore 20 of the component 4, 5. For this purpose, the rubber sleeve 23 is slipped over the shaft 2 of the valve 3. The component 4, 5 is then placed onto the rubber sleeve 23 and pressed onto the rim 8. After that, another sleeve 22 made of inelastic material is inserted into the bore 20 of the component 4, 5 until it rests on the rubber sleeve 23. The valve nut 10 is now screwed onto the shaft 2 of the valve 3 and tightened until the inelastic sleeve 22 rests with the collar on the component 4, 5. As a result, the rubber sleeve 23 is deformed so much that it is pressed between the valve thread and the wall of the bore 20 (reference number 24). This ensures that the device is protected against rotation.

[0059] Possible advantages of this embodiment are Component 4, 5 can be designed very simply and slenderly Simple, cost-effective production in large quantities All rim shapes can be used No loosening of component 4, 5 in case of pressure fluctuations in the tire

[0060] Figure 12 shows a rim assembly according to an embodiment of the present invention.

[0061] In the Figure 12 In the embodiment shown, the anti-twist device 7 is created by the material of the housing 5 of the magnet 4. The magnet 4 is overmolded with an elastomer 5a, which has a high coefficient of friction and is at least partially deformed. The design of the overmold 5a is selected such that the overmold 5a on the underside of the component 4, 5 deforms and tightens when screwed onto the shaft 2 of the valve 3. In particular, as in Figure 12As shown, the overmolding 5a is not flat with respect to the surface of the rim 8, but is selected such that when the overmolding 5a is applied, cavities 58 are formed between the housing 5 and the rim 8. When screwed together, the elastomer deforms and the cavities 58 are filled by the elastomer. The force thus generated clamps the component 4, 5 against the valve nut 10. In conjunction with the increased coefficient of friction between the elastomer and, for example, an aluminum rim, the anti-twist device 7 is ensured. In addition, the system is clamped relative to the valve screw 10, which makes the system less susceptible to pressure fluctuations.

[0062] Possible advantages of this embodiment are Component 4, 5 can be designed very simply and slenderly Simple, cost-effective production in large quantities All rim shapes can be used No loosening of component 4, 5 in case of pressure fluctuations in the tire

[0063] Embodiments not shown are described below.

[0064] In an embodiment not shown here, the anti-twist device 7 is provided in that the majority of the central bore 20 in the component 4, 5 is undersized compared to the shaft 2 of the valve 3. In the lower part of the bore 20 in the area of ​​the rim 8, in particular the first three threads of the valve thread are cut. The component 4, 5 is then secured by screwing it onto the shaft 2 of the valve 3. The thread of the valve 3 cuts into the wall of the bore 20 of the housing, here in the form of an overmolding. The material of the overmolding is selected such that, on the one hand, the thread is cut and, on the other hand, the friction on the threads of the shaft 2 of the valve 3 is high. In this way, an anti-twist device 7 can be ensured.The variation between Presta and Schrader valves is ensured in particular by choosing a wall thickness of bore 20 that allows for easy reaming from Presta to Schrader core hole diameters. The valve nut 10 can be screwed on as an additional security feature. Possible advantages of this design include: Component 4, 5 can be designed very simply and slim Valve variation can be easily implemented by a mechanic, customer or the like Simple, cost-effective production in large quantities All rim shapes can be used No loosening of component 4, 5 in the event of pressure fluctuations in the tire Valve nut is no longer required and can be omitted.

[0065] In summary, at least one of the embodiments of the invention has at least one of the following advantages: Simple, cost-effective production, especially in large quantities. Easy to install. Reliable fixation, both axially and circumferentially on the valve stem. Insensitivity to pressure fluctuations with respect to the position on the rim. Few components for fixation.

[0066] Overall, a monomagnet 4 can have at least one of the following properties: Remanence between 1.30T and 1.4T, especially between 1.32T and 1.35T Length: 35mm-50mm, especially 40-45mm Width: 10-20mm, especially 12.5-17.5mm Height: 5-20mm, especially 6-9mm Weight (without / with housing): 15-20g / 20-30g Magnetization level at least N45, at least level M, especially level H

[0067] Overall, a component 4, 5 with a two-part magnet 4 can have at least one of the following properties: Remanence between 1.40T and 1.5T, in particular between 1.42T and 1.48T Length: 35mm-50mm, in particular 40-45mm Width: 10-20mm, in particular 12.5-17.5mm Height: 5-20mm, in particular 6-9mm Individual magnet length: 10mm-20mm, in particular 12-15mm Individual magnet width: 10-20mm, in particular 12.5-17.5mm Individual magnet height: 5-20mm, in particular 6-9mm Weight (without / with housing): 15-20g / 20-30g Magnetization degree at least N45, in particular N52, at least level M

[0068] Although the present invention has been described with reference to preferred embodiments, it is not limited thereto, but can be modified in many ways within the scope of the appended claims.

Claims

1. Rim magnet arrangement (1) for fixing a magnet on a rim (8) by means of a stem (2) of a valve (3), comprising a magnet (4), a fixing device (6, 10) which is configured to fix the magnet (4) on the stem (2) of the valve (3) in the axial direction (100) of the stem (2), and an anti-rotation safeguard (7) which is configured to fix the magnet (4) in the circumferential direction (101) of the stem (2), characterized in that the anti-rotation safeguard (7): - is formed by an adhesive applied to the magnet (4) and / or its housing (5), in particular in the form of a double-sided adhesive tape (15), and / or - a clip (16) with a U-shaped cross-sectional profile which can be fixed on the stem (2) and is configured, in the fixed state of the magnet (4), to prevent a rotation by means of a positively locking connection to the magnet (4) and / or to the housing (5) firstly and at least partially to a rim (8) secondly, and / or - at least one element which increases the coefficient of friction, and / or - comprises a pressing sleeve arranged on the stem (2) of the valve (3) and / or provided by elastic material of the housing (5) of the magnet (4), and / or - comprises a forming sleeve (12) which has at least one recess or projection (13) which engages into a corresponding projection or recess (14) of the magnet (4) and / or its housing (5), and the magnet (4) is arranged in the housing (5).

2. Rim magnet arrangement according to Claim 1, wherein the magnet (4) is arranged in a housing (5), in particular produced from plastic.

3. Rim magnet arrangement according to Claim 1 or 2, wherein the fixing device (6) has a screwing device (10) which can be screwed onto the stem (2) of the valve (3).

4. Rim magnet arrangement according to Claim 2, wherein the housing (5) has at least one resilient element (11) which is configured so as to project on the housing (5) in the axial direction (100) of the stem (2), and is configured, in particular, so as to taper partially inwards to the centre of the housing (5).

5. Rim magnet arrangement according to Claim 4, wherein at least two, in particular four, resilient elements (11) are arranged which are arranged symmetrically on the housing (5) and, in particular, are of identical configuration.

6. Rim magnet arrangement according to one of Claims 1-5, wherein the anti-rotation safeguard (7) comprises, in the housing (5) of the magnet (4), a bore (20) with an undersize in relation to the diameter of the stem (2).

7. Rim magnet arrangement according to one of Claims 1-6, wherein the magnet (4) is of single-part configuration, and the magnet (4) and, in particular, the housing (5) have a bore (20) which corresponds to each other and is, in particular, central for fixing on the stem (2) of the valve (3).

8. Rim magnet arrangement according to one of Claims Claim 2-7, wherein the magnet (4) is of two-part configuration, and a receiving device (21) for the two parts (4a, 4b) of the magnet (4) is arranged in the housing (5).

9. Rim magnet arrangement according to one of Claims 1-8, wherein the magnet (4) is arranged in such a way that it provides a magnetic field (200) perpendicularly with respect to the axial direction (100) of the stem (2) of the valve (3) or parallel to its axial direction (100).

10. Method for producing a rim magnet arrangement according to one of Claims 1-9 for fixing a magnet on a rim (8) by means of a stem (2) of a valve (3), comprising a magnet (4), a fixing device (6, 10) which is designed to fix the magnet (4) on the stem (2) of the valve (3) in the axial direction (100) of the stem (2), and an anti-rotation safeguard (7) which is designed to fix the magnet (4) in the circumferential direction (101) of the stem (2), wherein the magnet (4) is arranged in a housing (5), in particular produced from plastic, and wherein the housing (5) is produced by means of a two-component injection moulding process.

11. Bicycle with a rim comprising a rim magnet arrangement according to one of Claims 1-9.