Grounding brush, grounding brush unit and device
The grounding brush with diverse thread materials addresses efficiency and lubrication issues by using carbon fibers, solid lubricants, and thermally conductive fibers, resulting in reduced noise, wear, and improved shaft contact, ensuring effective operation in dry conditions.
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-09-27
- Publication Date
- 2026-04-02
AI Technical Summary
Existing grounding brushes face challenges in achieving high efficiency, effective lubrication, minimizing friction and wear, and maintaining electrical conductivity while operating in dry environments without liquid lubricants.
A grounding brush with threads of different types, including electrically conductive carbon fibers, solid lubricants like polytetrafluoroethylene and graphene, and thermally conductive pitch-based carbon fibers, designed to minimize friction, reduce wear, and enhance electrical and thermal conductivity.
The solution achieves reduced noise, lower wear, improved shaft contact retention, and efficient cooling, while maintaining electrical conductivity without the need for liquid lubricants, extending component lifespan and enhancing operational efficiency.
Smart Images
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Abstract
Description
[0001] The invention relates to a grounding brush, a grounding brush unit and a device with a grounding brush unit.
[0002] A grounding brush unit with graphite threads is known. It is also known to use grounding brushes on coated areas of shafts and on coated bushings located on a shaft.
[0003] The problem addressed by the invention is, in particular, to achieve high efficiency. This problem is solved according to the invention by the features of claim 1, while advantageous embodiments of the invention are the subject of the dependent claims.
[0004] The invention relates to a grounding brush with a first quantity of threads belonging to a first type and at least a second quantity of threads.
[0005] It is proposed that the threads of the second batch belong to a second type, which differs from the first type. The expression that a thread “belongs to a type” is understood to mean, in particular, that the thread is made of a material specific to that type, and / or has a mass that differs by less than 20 percent by weight from a mass specific to that type, and / or has an electrical conductivity that differs by less than 20 percent from an electrical conductivity specific to that type.The expression "different" from the first type means, in particular, that a material specific to the first type differs from a material specific to the second type, and / or that a mass specific to the first type differs by more than 5% from a mass specific to the second type, and / or that an electrical conductivity specific to the first type differs by more than 5% from an electrical conductivity specific to the second type. "Quantity" means, in particular, a quantity in the mathematical sense. This allows for high efficiency. In particular, it allows for the effective development of a property of the grounding brush that differs from its electrical conductivity.
[0006] In particular, a thread can be a fiber and / or a bristle and / or a piece of wire. Specifically, the threads of the first set can be electrically conductive. For example, the threads of the first set can be carbon fibers.
[0007] Advantageously, the threads of the second batch consist at least predominantly of a solid lubricant or of more than one solid lubricant. The expression "predominantly" of a thread is understood to mean, in particular, that a portion of the thread comprising more than fifty percent by weight is made of that material. This allows for good lubrication of the relative movement between the threads of the first batch and a shaft during operation, especially in cases where the environment surrounding the threads of the first batch is dry and therefore devoid of a liquid lubricant. Specifically, friction between the threads of the first batch and the shaft can be minimized, and abrasive wear and oxidation of the shaft, as well as a reduction in electrical conductivity between the threads of the first batch and the shaft, can be largely avoided.
[0008] Furthermore, it is proposed that the threads of the second batch consist at least partially of polytetrafluoroethylene and / or graphene. This would result in low noise during operation, low wear on a shaft in contact with the threads of the second batch during operation, and good shaft contact retention during operation.
[0009] Advantageously, the grounding brush includes a third set of threads belonging to a third type, which differs from the first and second types. This allows for high efficiency. In particular, the grounding brush exhibits several properties beyond electrical conductivity. Specifically, the threads of the third set can have better thermal conductivity than the threads of the first and second sets.
[0010] Furthermore, it is proposed that the threads of the second batch have a higher thermal conductivity than the threads of the first batch. This would ensure good cooling and low wear of material that comes into contact with the grounding brush during operation.
[0011] In particular, a thermal conductivity specific to the second type of threads can be at least 15% higher than a thermal conductivity specific to the first type of threads.
[0012] The second batch of threads is advantageously made of pitch-based carbon fibers. This allows for a particularly high thermal conductivity of the second batch of threads.
[0013] Advantageously, the total number of threads in the first batch is between 40% and 75% of the total number of threads in the grounding brush, and / or the total number of threads in the second batch is between 25% and 60% of the total number of threads in the grounding brush. This ensures a good balance between the effectiveness of the threads in the first batch and the effectiveness of the threads in the second batch.
[0014] Furthermore, a grounding brush unit with a grounding brush, as described above, is proposed, with a support unit attached to the grounding brush unit. This allows for an efficient mounting option for the grounding brush to a housing.
[0015] Furthermore, a device with a grounding brush unit is proposed.
[0016] Advantageously, the device includes a shaft with a surface area that contacts the grounding brush and is free of coatings. This allows for a cost-effective design.
[0017] Further advantages can be seen in the following description of the drawings. An example of an embodiment of the invention is shown in the drawings. The drawings, the description, and the claims contain numerous features in combination. It will be advantageous for the person skilled in the art to also consider the features individually and combine them to form further useful combinations. Fig. Figure 1 shows a view of an end face of a grounding brush unit with a grounding brush according to the invention, Fig. Figure 2 shows a II-II section through the grounding brush unit according to Fig. 1, Fig. Figure 3 shows a III-III section through a device with the grounding brush unit according to Fig. 1, and Fig. Figure 4 shows a perspective view of the grounding brush unit.
[0018] Fig. Figure 1 shows a view of an end face of a grounding brush unit 20 with a grounding brush 10 according to the invention. The grounding brush unit 20 comprises a one-piece metallic support unit 18 which is attached to the grounding brush in a form-fitting manner ( Fig. 1 to 4). The grounding brush comprises an initial set of 12 threads ( Fig. 3), belonging to a first type. The grounding brush also includes a second set of threads 14 belonging to a second type. The first and second types differ. The threads 12 of the first set are carbon fibers, which are electrically conductive. The threads 14 of the second set consist entirely of graphene. Alternatively, the threads 14 of the second set consist partially or entirely of polytetrafluoroethylene. Alternatively, it is also possible that the second set includes threads consisting entirely or partially of polytetrafluoroethylene and threads consisting of graphene. Therefore, the threads 14 consist at least partially of a solid lubricant. The threads 14 also have a cleaning effect during operation.
[0019] Furthermore, the grounding brush comprises a third set of threads 16 belonging to a third type. The threads 16 of the third type are pitch-based carbon fibers. The threads 16 of the third set have a higher thermal conductivity than the threads of the first set. Therefore, in a fully assembled state, they contribute to cooling a shaft 24. In the fully assembled state, the grounding brush unit is part of a device 22 ( Fig. 3) In this state, the carrier unit 18 is attached in a press fit to a housing 28 of the device by parts 30 of ring segment-shaped pieces 32 of the carrier unit 18, which extend axially in the direction of the grounding brush.
[0020] The grounding brush 10 has the shape of a ring segment. This ring segment is almost a ring. All the threads of the grounding brush are attached to a support element 36 of the grounding brush by means of a wire 34. The support element 36 also has the shape of a ring segment. Furthermore, this latter ring segment is also almost a ring. In an axial section ( Fig. 2 and Fig. 3) The support element is U-shaped, with its ends bent towards each other so that they compress the threads of the grounding brush, resulting in the threads being attached to the support element 36. Tabs 38 of the support unit are bent around the support element 36 so that the support element 36 is attached to the support unit 18 ( Fig. 2) Overall, the threads of the grounding brush are connected to the carrier element and the carrier unit in an electrically conductive manner to the housing 28. The housing 28 is also electrically conductive.
[0021] The device 22 comprises the shaft 24, which rotates relative to the housing 28 and relative to the grounding brush unit during an operating procedure. The shaft includes a surface area 26 that contacts the grounding brush 10 and is free of coatings.
[0022] The shaft 24 is rotatably mounted relative to the housing 28 by a bearing (not shown). In particular, during an operating procedure, an electric current can flow from the shaft 24, through the first set of threads 12 and through the support element and the support unit, to the housing 28. This prevents the current from flowing through the bearing to the housing 28, thus protecting the bearing from damage.
[0023] The device can be free of liquid lubricant in the area containing the grounding brush.
[0024] The device can, for example, be part of an electric motor that provides power to a vehicle or be part of an industrial application.
[0025] All the threads of the grounding brush can be fibers.
[0026] Fig. Figure 4 shows a perspective view of the grounding brush unit.
[0027] In comparison to a grounding brush with graphite fibers, the grounding brush of the invention has in particular the following advantages: less noise, less wear (which extends the service life of the components, especially the shaft) and a better ability to maintain contact with the shaft due to the flexibility of the threads.
[0028] Alternatively, the grounding brush is free of the threads 16 of the third quantity. In this case, the total number of threads 12 of the first quantity is between 40% and 75%, specifically between 50% and 66%, of the total number of threads of the grounding brush. Furthermore, in this case, the total number of threads 14 of the second quantity is between 25% and 60%, specifically between 33% and 50%, of the total number of threads of the grounding brush.
[0029] Alternatively, the grounding brush is free of the threads 14 of the second quantity. Reference symbol list 10 grounding brushes 12 threads 14 threads 16 threads 18 carrier units 20 grounding brush unit 22 Device 24 wave 26 Area 28 cases 30 parts 32 pieces 34 wire 36 support element 38 tab
Claims
[1] Grounding brush (10) with a first set of threads (12) belonging to a first type and at least a second set of threads (14), characterized by , that the threads (14) of the second set belong to a second type, which differs from the first type. [2] Grounding brush (10) according to claim 1, characterized by , that each of the threads (14) of the second quantity consists at least mostly of a solid lubricant or of more than one solid lubricant. [3] Grounding brush (10) according to claim 2, characterized by , that the threads (14) of the second set consist at least partially of polytetrafluoroethylene and / or graphene. [4] Grounding brush (10) according to at least one of the preceding claims, characterized by , that the grounding brush comprises a third set of threads (16) belonging to a third type, and the third type differs from the first type and from the second type. [5] Grounding brush (10) according to at least one of the preceding claims, characterized by , that the threads (14) of the second quantity have a higher thermal conductivity than the threads (12) of the first quantity. [6] Grounding brush (10) according to claim 5, characterized by , that the threads (14) of the second quantity are pitch-based carbon fibers. [7] Grounding brush (10) according to at least one of the preceding claims, characterized by , that a total number of threads (12) of the first quantity is between 40% and 75% of a total number of threads (12, 14, 16) of the grounding brush and / or a total number of threads (14) of the second quantity is between 25% and 60% of the total number of threads (12, 14, 16) of the grounding brush. [8] Grounding brush unit (20) comprising a grounding brush (10) according to at least one of the preceding claims, characterized by a carrier unit (18) which is attached to the grounding brush. [9] Device (22) with a grounding brush unit (20) according to claim 8. [10] Device (22) according to claim 9, characterized by a shaft (24) with a surface area (26) that touches the grounding brush (10) and is free of coatings.