Conductive device and motor system
By using a rolling friction contact design between the ball bearings and the contact components, the problems of complex structure and wear in existing conductive devices are solved, achieving low-cost and high-efficiency conductivity and avoiding damage and interference of shaft current to the motor system.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SCHAEFFLER TECHNOLOGIES AG & CO KG
- Filing Date
- 2025-03-27
- Publication Date
- 2026-06-09
AI Technical Summary
Existing conductive devices have complex structures, the carbon brush and shaft contact area are prone to wear, they rely on lubrication and are costly, and cannot effectively solve the problems of bearing damage and motor instability caused by shaft current.
The conductive device is designed with a ball bearing and a contact component in tandem. The ball bearing and the contact component are in rolling friction contact, which reduces friction loss. The ball bearing is made of a hard conductive material, and the conductive head and the contact component maintain a conductive connection.
It achieves a simple and compact structure, reduces frictional loss, avoids rapid wear caused by sliding friction, reduces manufacturing costs, improves assembly efficiency, effectively dissipates shaft charge, and avoids damage and operational interference of shaft current to the motor system.
Smart Images
Figure CN224342714U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of motor technology. More specifically, this utility model relates to a conductive device for use in motor systems. Background Technology
[0002] During motor operation, shaft voltage can be generated at both ends of the motor shaft or between the shaft and bearings due to factors such as magnetic circuit imbalance within the motor and the presence of high-order harmonic components in the inverter's power supply voltage. Normally, a lubricating oil film exists between the motor shaft and bearings, providing insulation. When the shaft voltage increases to a certain level, it breaks down the oil film and discharges, forming a circuit and generating shaft current. Shaft current can cause problems such as bearing damage, damage to insulating components, unstable motor operation, and electromagnetic interference.
[0003] To mitigate the adverse effects of shaft current, a conductive device can be used to ground the motor shaft, thereby drawing the shaft current away from the shaft. Existing conductive devices typically use carbon brushes as contacts, with the brushes forming a conductive path with the shaft through sliding contact. However, this type of conductive device has a relatively complex structure, the contact area between the carbon brush and the shaft is prone to wear, and it is highly dependent on lubrication.
[0004] Therefore, a simple conductive device is needed. Utility Model Content
[0005] One objective of this invention is to provide a conductive device with a simple structure. Another objective of this invention is to provide a conductive device that reduces friction. A further objective of this invention is to provide a conductive device that reduces costs.
[0006] One aspect of the present invention provides a conductive device comprising: a housing including an axially extending receiving hole; a conductive head axially movably disposed in the receiving hole of the housing and including a recess at one axial end; a ball rotatably disposed in the recess and at least partially projecting axially out of the receiving hole; and an elastic member configured to conductively connect with the conductive head at another axial end and apply an axial force to the conductive head in a direction toward the ball.
[0007] According to an embodiment of the present invention, the conductive head is disposed in the receiving hole of the housing in a torsion-resistant manner.
[0008] According to an embodiment of the present invention, the conductive head includes a first segment and a second segment connected to each other along the axial direction, a recess is provided on the first segment, and the second segment is used to connect an elastic element. The first segment has a non-circular cross-section and is configured to fit the shape of a receiving hole to prevent the conductive head from rotating circumferentially.
[0009] According to an embodiment of the present invention, the first segment of the conductive head has a square cross-section, and the second segment has a circular cross-section.
[0010] According to an embodiment of the present invention, the first segment and the second segment of the conductive head are integrally formed.
[0011] According to an embodiment of the present invention, the center of the ball is located in the recess along the axial direction.
[0012] According to an embodiment of the present invention, the ball bearing is made of a hard conductive material.
[0013] According to an embodiment of the present invention, the receiving hole is a through hole extending along the axial direction, and the conductive device further includes: a fixing member disposed at the end of the receiving hole away from the conductive head, wherein the elastic member is disposed along the axial direction between the conductive head and the fixing member and maintains conductive connection with the conductive head and the fixing member respectively.
[0014] Another aspect of the present invention provides a motor system comprising: a shaft; a contact member torsionally connected to the shaft; and a conductive device according to an embodiment of the present invention, configured such that a ball bearing of the conductive device remains conductively connected to the contact member.
[0015] According to an embodiment of the present invention, the motor system further includes: an end cap having a mounting hole, wherein the conductive device is shaped to fit within the mounting hole and protrudes at least partially out of the mounting hole along the axial direction.
[0016] This invention provides an improved conductive device and a motor system including the conductive device. According to an embodiment of this invention, the conductive device employs a structure design where a ball bearing and a contact component cooperate, resulting in a simple and compact structure that provides a direct conductive channel for the rotating shaft, effectively dissipating the charge generated on the shaft. In this invention, the ball bearing and the contact component engage in rolling friction contact, significantly reducing friction loss and eliminating the need for a dedicated lubrication structure, thus avoiding the rapid wear problem caused by sliding friction in existing technologies. Furthermore, the various components of the conductive device of this invention can be manufactured independently and are easy to assemble, which not only improves assembly efficiency but also reduces manufacturing costs. Attached Figure Description
[0017] Figure 1 An exploded view of an electric motor system including a conductive device according to an embodiment of the present invention.
[0018] Figure 2 This is a schematic diagram of a conductive device according to an embodiment of the present invention. Detailed Implementation
[0019] Hereinafter, embodiments of the present invention are described with reference to the accompanying drawings. The following detailed description and drawings are provided to exemplarily illustrate the principles of the present invention. The present invention is not limited to the described preferred embodiments, and the scope of the present invention is defined by the claims. The present invention will now be described in detail with reference to exemplary embodiments, some of which are illustrated in the accompanying drawings. The following description is made with reference to the accompanying drawings, and unless otherwise indicated, the same reference numerals in different drawings represent the same or similar elements. The solutions described in the following exemplary embodiments do not represent all solutions of the present invention. Rather, these solutions are merely examples of systems and methods of various aspects of the present invention covered by the appended claims.
[0020] This invention provides a motor system. The motor system according to an embodiment of this invention can be installed in a vehicle. Exemplary embodiments of this invention will now be described with reference to the accompanying drawings. Figure 1 An exploded view of an electric motor system including a conductive device according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a conductive device according to an embodiment of the present invention.
[0021] According to embodiments of the present invention, such as Figure 1 As shown, the motor system includes a shaft 1, a contact member 2 connected to the shaft 1 in a torsionally resistant manner, and a conductive device 3. The shaft 1 may be the shaft of a motor. The contact member 2 is disposed at the axial end of the shaft 1. In an exemplary embodiment, the contact member 2 is connected to the axial end of the shaft 1 by an interference fit. During operation of the motor system, the contact member 2 rotates together with the shaft 1. The contact member 2 is made of a conductive material and is electrically connected to the shaft 1. The conductive device 3 is used to electrically connect to the contact member 2 to release the charge or voltage generated on the shaft 1 to the outside of the motor system.
[0022] In an exemplary embodiment, such as Figure 1 As shown, the motor system also includes a housing 4, an end cap 5, and bolts 6. The housing 4 is used to house the motor system's shaft 1 and other components, such as a rotor and stator. The end cap 5 includes a mounting hole 5'. A conductive device 3 is form-fitted into the mounting hole 5' of the end cap 5. The conductive device 3 protrudes at least partially axially beyond the mounting hole 5' for contact with the contact member 2. In an exemplary embodiment, the mounting hole 5' is a through hole. Bolts 6 are connected to the end cap 5 from the side of the mounting hole 5' away from the conductive device 3 to contact and secure the conductive device 3. During installation, the conductive device 3 and bolts 6 can be installed onto the end cap 5 first, and then the end cap 5 can be connected to the housing 4.
[0023] According to embodiments of the present invention, such as Figure 2As shown, the conductive device 3 includes a housing 10, a conductive head 20, a ball bearing 30, an elastic element 40, and a fixing element 50. The conductive device 3 is used to maintain a conductive connection with the contact component 2 of the motor system.
[0024] The housing 10 has a receiving hole 11 extending axially. In an exemplary embodiment, the receiving hole 11 extends through the entire axial length of the housing 10, i.e., the receiving hole 11 is a through hole. In some embodiments, the housing 10 has a cylindrical structure extending axially. In some embodiments, the housing 10 is made of an insulating material, such as plastic.
[0025] The conductive head 20 is axially movable within a receiving hole 11 of the housing 10. The conductive head 20 includes a recess 21 located at one axial end facing the rotating shaft 1 for receiving a ball 30. The conductive head 20 is made of a conductive material.
[0026] In an exemplary embodiment, the conductive head 20 is disposed in the receiving hole 11 of the housing 10 in a torsional manner to prevent the conductive head 20 from rotating circumferentially within the housing 10. In some embodiments, the conductive head 20 includes a first segment 22 and a second segment 23 connected axially. A recess 21 is provided on the first segment 22. The first segment 22 has a non-circular cross-section, such as a square cross-section, to fit the shape of the receiving hole 11 of the housing 1, thereby preventing circumferential rotation of the conductive head 2. The second segment 23 has a circular cross-section for connecting the elastic member 40. In some embodiments, the first segment 22 and the second segment 23 are integrally formed to ensure structural stability and conductivity.
[0027] A ball 30 is rotatably disposed in the recess 21 of the conductive head 20. The ball 30 is configured to partially protrude axially from the receiving hole 11 for conductive contact with the contact member 2. In an exemplary embodiment, the ball 30 is a sphere. The ball 30 is made of a hard conductive material to ensure high conductivity and wear resistance. In an exemplary embodiment, the center of the ball 30 is located axially within the recess 21. This design ensures that the ball 30 can rotate stably within the recess 21 while maintaining good conductive contact.
[0028] The elastic element 40 is electrically connected to the conductive head 20 at another axial end of the conductive head 20. More specifically, the elastic element 40 is electrically connected to the second segment 23 of the conductive head 20. The elastic element 40 is used to apply an axial force to the conductive head 20 in the direction toward the ball 30 to ensure reliable contact between the ball 30 and the contact member 2. In an exemplary embodiment, the elastic element 40 is a helical compression spring. In some embodiments, the elastic element 40 is axially disposed between the conductive head 20 (the second segment 23) and the fixing member 50, and is electrically connected to both the conductive head 20 and the fixing member 50, respectively. The elastic element 40 is made of a conductive material.
[0029] The retainer 50 is connected to the housing 10 at the end of the housing 10 away from the ball 30. In an exemplary embodiment, the retainer 50 is threaded to the housing 10. The retainer 50 is used to electrically connect with and secure the elastic member 40 in the axial direction. The retainer 50 is made of a conductive material.
[0030] In some embodiments, during the assembly of the conductive device 3, the ball bearing 30 is pressed into the recess 21 of the conductive head 20, and then the conductive head 20 is inserted into the receiving hole 11 of the housing 10. Afterwards, the elastic member 40 can be placed into the receiving hole 11, and the fixing member 50 is connected to the housing 10 so that the elastic member 40 maintains a conductive connection with the conductive head 20 and the fixing member 50.
[0031] In some embodiments, during the installation of the conductive device 3 into the motor system, the contact member 2 is connected to the axial end of the shaft 1 located in the housing 4, while the conductive device 3 is disposed in the mounting hole 5' of the end cover 5. The end cover 5 can then be connected to the housing 4. Bolts 6 can then be connected to the end cover 5 to secure the conductive device 3 and maintain a conductive connection between the ball bearing 30 of the conductive device 3 and the contact member 2.
[0032] During the use of the conductive device 3, when the shaft 1 and the contact member 2 rotate, the ball 30 can rotate within the recess 21 of the conductive head 20 and maintain a conductive connection with the contact member 2. Thus, the charge generated on the shaft 1 can be conducted through the contact member 2 to the ball 30 of the conductive device 3, and then from the ball 30 through the conductive head 20 and the elastic member 40 to the fixing member 50. Therefore, a conductive path can be provided for the shaft 1, allowing the charge on the shaft 1 to flow to ground, avoiding or reducing problems such as component damage and operational interference caused by shaft current to the motor system.
[0033] This invention provides an improved conductive device and a motor system including the conductive device. According to an embodiment of this invention, the conductive device employs a structure design where a ball bearing and a contact component cooperate, resulting in a simple and compact structure that provides a direct conductive channel for the rotating shaft, effectively dissipating the charge generated on the shaft. In this invention, the ball bearing and the contact component engage in rolling friction contact, significantly reducing friction loss and eliminating the need for a dedicated lubrication structure, thus avoiding the rapid wear problem caused by sliding friction in existing technologies. Furthermore, the various components of the conductive device of this invention can be manufactured independently and are easy to assemble, which not only improves assembly efficiency but also reduces manufacturing costs.
[0034] Although the present invention has been described with reference to exemplary embodiments, it should be understood that the present invention is not limited to the construction and methods of the above embodiments. Rather, the present invention is intended to cover various modifications and equivalent configurations. Furthermore, although various elements and method steps of the disclosed invention have been shown in various exemplary combinations and constructions, other combinations including more or fewer elements or methods also fall within the scope of the present invention.
[0035] List of reference numerals
[0036] 1. Shaft;
[0037] 2. Contact components;
[0038] 3. Conductive devices;
[0039] 4. Outer shell;
[0040] 5. End caps;
[0041] 5' mounting holes;
[0042] 6 bolts;
[0043] 10. Casing;
[0044] 11 receiving holes;
[0045] 20 conductive heads;
[0046] 21 concavity;
[0047] 22. First segment;
[0048] 23. Second segment;
[0049] 30 ball bearings;
[0050] 40 elastic elements;
[0051] 50 Fasteners.
Claims
1. A conductive device (3), characterized in that, The conductive device (3) includes: The housing (10) includes a receiving hole (11) extending axially; A conductive head (20) is axially movably disposed in the receiving hole (11) of the housing (10) and includes a recess (21) located at one axial end; A ball bearing (30), rotatably disposed in the recess (21) and at least partially protruding axially out of the receiving hole (11); and An elastic element (40) is configured to electrically connect to the conductive head (20) at the other axial end of the conductive head (20) and apply an axial force to the conductive head (20) in the direction toward the ball (30).
2. The conductive device (3) according to claim 1, characterized in that, The conductive head (20) is disposed in the receiving hole (11) of the housing (10) in a torsion-resistant manner.
3. The conductive device (3) according to claim 2, characterized in that, The conductive head (20) includes a first segment (22) and a second segment (23) connected to each other along the axial direction. The recess (21) is disposed on the first segment (22), and the second segment (23) is used to connect the elastic member (40). The first segment (22) has a non-circular cross-section and is configured to fit the shape of the receiving hole (11) to prevent the conductive head (20) from rotating circumferentially.
4. The conductive device (3) according to claim 3, characterized in that, The first segment (22) of the conductive head (20) has a square cross-section, and the second segment (23) has a circular cross-section.
5. The conductive device (3) according to claim 4, characterized in that, The first segment (22) and the second segment (23) of the conductive head (20) are integrally formed.
6. The conductive device (3) according to any one of claims 1 to 5, characterized in that, The center of the ball (30) is located in the recess (21) along the axial direction.
7. The conductive device (3) according to claim 6, characterized in that, The ball (30) is made of a hard conductive material.
8. The conductive device (3) according to claim 7, characterized in that, The receiving hole (11) is a through hole extending axially, and the conductive device (3) further includes: A fixing member (50) is disposed at one end of the receiving hole (11) away from the conductive head (20), wherein the elastic member (40) is disposed axially between the conductive head (20) and the fixing member (50) and maintains conductive connection with the conductive head (20) and the fixing member (50) respectively.
9. A motor system, characterized in that, The motor system includes: Shaft (1); Contact component (2), which is torsionally connected to the rotating shaft (1); and The conductive device (3) according to any one of claims 1 to 8 is configured such that the ball (30) of the conductive device (3) maintains a conductive connection with the contact member (2).
10. The motor system according to claim 9, characterized in that, The motor system also includes: End cap (5) includes mounting hole (5'), wherein the conductive device (3) is shaped fitly disposed in the mounting hole (5') and at least partially protrudes axially from the mounting hole (5').