Low impedance axial conductive rod

Abstract

The utility model relates to a kind of low-impedance axial conductive rod, including carbon brush, brush grip, brush grip fixing seat, spring;Brush grip is fixed in brush grip fixing seat by clamping screw, and brush grip is upper circle lower structure for accommodating spring and carbon brush, and carbon brush is connected with brush grip by brush braid line;Conductive rod is installed in the blind hole of motor casing, and the carbon brush of conductive rod is in contact with the axial plane rotation of motor spindle, and the charge of main shaft is conducted to the casing by carbon brush, i. e. ground connection. The utility model low-impedance conductive rod is especially suitable for the situation that installation space is not reserved for grounding ring on motor, and only a blind hole is machined on the casing, the conductive ring can be directly pressed and assembled without other installation steps, and efficient low-impedance grounding can be realized, thereby effectively prolonging the service life of motor.

Description

Technical Field

[0001] This utility model relates to a conductive rod with a brush, and more particularly to a low-impedance axial conductive rod. Background Technology

[0002] As the electrical architecture of new energy vehicles upgrades to 1000V or even higher voltages, it means that the shaft current of the drive motor will cause more damage to the motor bearings. Firstly, the motor controller of new energy vehicles converts direct current into high-frequency alternating current to drive the motor. The capacitive voltage induced by this current conversion is coupled to the motor shaft, causing high-frequency discharge and erosion of the bearing. Secondly, the high-frequency magnetic flux generated by the common-mode current of the motor controller can also induce high-frequency loop currents within the drive motor, which also damage the bearings. Therefore, a conductive module is needed to discharge the harmful shaft current and protect the bearings from electrolytic corrosion. Typically, a brush grounding system is the most effective and longest-lasting grounding solution for shaft current discharge.

[0003] However, in many scenarios, motor designs do not prioritize shaft current conduction, meaning no installation space is reserved for the conductive module. Some existing grounding conductivity schemes use radial conduction, where current is conducted through the outer surface of the spindle. This requires reserving space in the motor for a conductive ring, making this approach infeasible without such space. Another scheme involves conducting shaft current through the spindle end face, i.e., axial grounding. In many axial grounding schemes, the carbon brushes lack brush braids. In existing designs, the brush end face conducts electricity through contact with the brush holder or spring, rather than through the brush braids. This design results in an obstructed charge conduction path, high impedance, and an inability to effectively extend bearing life. Utility Model Content

[0004] This invention addresses the aforementioned problems by disclosing a low-impedance axial conductive rod. It solves the high contact impedance issue in some axial designs caused by the lack of effective connection between the carbon brush and the brush holder, and also eliminates the need for additional installation space and installation processes in existing technologies to install the grounding module. The conductive rod, cylindrical in shape, can be installed simply by creating a blind hole in the motor cover. The carbon brush and brush holder are connected by copper wire, and the brush holder and brush holder mounting base are fastened with screws. Conductivity is achieved through contact between the brush holder mounting base and the motor cover. Installation is completed by simply pressing the conductive rod into the inner hole of the end cover. This solves the problem of low-impedance effective grounding when motor space is limited, and also simplifies installation.

[0005] The specific technical solution is as follows:

[0006] A low-resistance axial conductive rod is disposed on a motor housing with a blind hole. The conductive rod includes a carbon brush, a brush holder, a brush holder fixing seat, and a spring. A carbon brush is disposed at one end of the inner cavity of the brush holder, and the carbon brush is connected to the other end of the brush holder through a brush braid. The spring is disposed in the inner cavity of the brush holder and supports the carbon brush outward, so that the carbon brush contacts the spindle. The outer periphery of the other end of the brush holder is embedded in the brush holder fixing seat and connected and fixed thereto. A cylindrical boss is provided at one end of the brush holder fixing seat, and a tapered mating surface is provided at one end of the boss. The brush holder fixing seat is embedded in the blind hole of the housing through the boss, and the outer periphery of the boss is interference-fitted with the inner wall of the blind hole of the housing to realize the installation and positioning of the conductive rod.

[0007] Furthermore, the outer periphery of the brush holder fixing seat is cylindrical, and the diameter of the brush holder fixing seat is larger than the diameter of the boss, so that the end face of one end of the brush holder fixing seat forms a flange face for pressing onto the surface of the motor housing.

[0008] Furthermore, the brush holder and the brush holder fixing seat are preferably fitted with a transition fit, that is, the brush holder fixing seat has a screw hole on its side and a set screw is threadedly connected thereto. One end of the set screw presses against and positions the brush holder, thereby connecting and fixing the brush holder and the brush holder fixing seat. The brush holder and the brush holder fixing seat can also be fitted with an interference fit.

[0009] Furthermore, the inner cavity of the brush holder has a square structure at one end and a circular structure at the other end. The square-section cavity at one end of the brush holder is used to accommodate the carbon brush, and the circular-section cavity at the other end of the brush holder is used to accommodate the spring.

[0010] Furthermore, one end of the brush holder is provided with a central hole for accommodating the carbon brush braid.

[0011] Furthermore, the preferred method for fixing the carbon brush braid to the brush holder is soldering, but riveting or fusion fixing is also acceptable.

[0012] Furthermore, the carbon brush is preferably rectangular in shape, with the brush braid connected to the top of the carbon brush.

[0013] Furthermore, the spring is preferably a cylindrical helical compression spring, with both ends of the spring contacting the end face of the carbon brush and the inner wall of one end of the brush holder, respectively. The center of the spring accommodates the movement of the brush braid, so that after the conductive rod is installed with the housing, the spring pushes the carbon brush to maintain stable contact with the axial end face of the spindle.

[0014] The beneficial effects of this utility model are reflected in:

[0015] (1) Low Impedance Design: This invention integrates a grounding carbon brush and a current lead-out structure within a limited space of the rotating body. By rationally setting the current conduction path between the carbon brush and the conductive rod, the grounding impedance is effectively reduced. Furthermore, high-reliability metal contact connections are used between the carbon brush and the conductive rod, and between the brush holder and the brush holder mounting base, meeting stringent automotive-grade requirements. This design eliminates the need for additional space to install a grounding module in the motor, achieving efficient and low-impedance grounding, thereby effectively extending the motor's service life.

[0016] (2) Integrated and efficient installation without the need for pre-reserved installation space: In this utility model, the conductive rod eliminates the need for additional installation steps when installing with the housing, abandoning the traditional bolt fixing method. Installation can be completed in one press-fit, which greatly improves production efficiency. At the same time, the brush holder fixing seat is made of metal and is interference-fitted with the motor housing, which not only ensures the structural strength during the press-fit process, but also gives the product excellent impact resistance. Attached Figure Description

[0017] Figure 1 This is a perspective view of the conductive rod in this utility model.

[0018] Figure 2 This is a side sectional view of the conductive rod in the free state in this utility model.

[0019] Figure 3 This is a side view of the conductive rod in this utility model.

[0020] Figure 4 This is a perspective view of the brush holder in this utility model.

[0021] Figure 5 This is a central cross-sectional view of the brush holder in this utility model.

[0022] Figure 6 This is a cross-sectional view of the conductive rod and motor after installation in this utility model.

[0023] Explanation of reference numerals in the attached drawings: 1. Carbon brush; 2. Brush holder; 3. Brush holder mounting base; 4. Spring; 5. Solder; 8. Set screw; 11. Brush body; 12. Brush braid; 21. Square cavity; 22. Circular cavity; 23. Center hole; 32. Flange face; 33. Blind hole of brush holder mounting base; 34. Boss; 6. Motor housing; 61. Blind hole in housing; 7. Spindle. Detailed Implementation

[0024] To make the technical solution of this utility model clearer and more explicit, the utility model will be further described below with reference to the accompanying drawings. Any solution derived by equivalent substitution and conventional reasoning of the technical features of this utility model falls within the protection scope of this utility model. The fixed connections and fixed settings mentioned in this utility model are all common connection methods in the mechanical field, including welding, bolt and nut connections, and screw connections.

[0025] In the description of this utility model, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0026] Please see the appendix Figure 1-5 This embodiment provides a low-impedance axial conductive rod, which is particularly suitable for situations where there is no space reserved for installing a grounding ring on the motor. Only a countersunk hole needs to be machined in the housing to directly press-fit the conductive ring without any other steps. Grounding is achieved by conducting the charge on the spindle 7 through the brushes, brush holders 2, and brush holder mounting base 3 to the housing. Axial grounding can effectively extend the lifespan of the motor, especially the drive motor of a new energy vehicle.

[0027] The conductive rod includes a carbon brush 1, a brush holder 2, a brush holder fixing seat 3, and a spring 4. The outer periphery of the brush holder 2 is a metal shell with a round upper part and a square lower part. One end of the brush holder 2 is open, and the inner cavity of the brush holder 2 at the open end is a square cavity 21 for accommodating the carbon brush 1 with a square cross-section. The size of the carbon brush 1 is adapted to the size of the square cavity 21. The inner cavity of the other end of the brush holder 2 is a circular cavity 22 for accommodating the spring 4 with a circular cross-section. The cylindrical end of the brush holder 2 is installed in the blind hole 33 of the brush holder fixing seat and is fixed by a set screw 8.

[0028] The brush holder fixing base 3 is a cylinder made of metal. One end of the brush holder fixing base 3 has a cylindrical boss 34 with a tapered mating surface. The brush holder fixing base 3 is inserted into the blind hole 61 of the housing through the boss. One end face of the brush holder fixing base 3 has a flange face 31, and the other end face near the boss forms a flange face 32 for press-fitting. Radial threaded holes are provided on the outer periphery of the brush holder fixing base 3, with set screws 8 threaded into them. One end of the set screw 8 presses against the outer wall of the brush holder 2, thus connecting and fixing the brush holder 2 to the brush holder fixing base 3. In another embodiment, the outer contour of the brush holder 2 is cylindrical, and one end of the brush holder 2 is press-fitted into the blind hole 33 of the brush holder fixing base, thus connecting and fixing the brush holder 2 to the brush holder fixing base 3.

[0029] like Figure 2As shown, the inner cavity of the brush holder 2 is provided with a brush braid 12 connected to the end face of the brush body 11 of the carbon brush 1. The other end of the brush braid 12 passes through the spring 4 and is connected to one end of the brush holder 2. One end of the brush holder 2 is provided with a central hole 23 for the brush braid 12 to pass through. The preferred method of fixing the brush braid 12 to the brush holder 2 is solder 5, but it can also be riveted or fused.

[0030] In this embodiment, the spring 4 is preferably a cylindrical helical compression spring 4. The two ends of the spring 4 are in contact with the end face of the carbon brush 1 and the end face of the brush holder 2, respectively. The center of the spring 4 accommodates the movement of the brush braid 12, so that after the conductive rod is installed with the housing, one end of the spring 4 extends into the square cavity 21 and pushes the carbon brush 1 to maintain stable contact with the axial end face of the main shaft 7.

[0031] In this embodiment, the brush holder 2 is made of a single sheet of brass sheet metal stamping, and the brush holder fixing base 3 is made of aluminum alloy.

[0032] like Figure 6 As shown, this embodiment provides a low-impedance axial conductive rod, which is mounted on a motor housing 6. The motor housing 6 has a blind hole 61 for mounting the conductive rod. During installation, one end of the boss of the brush holder fixing seat 3 is inserted into the blind hole 61. By pushing the flange surface 31 of the brush holder fixing seat 3, the flange surface 32 of its other end is brought into contact with the surface of the motor housing 6. At the same time, the outer periphery of the cylindrical boss of the brush holder fixing seat 3 is tightly fitted to the inner wall of the blind hole 61, completing the interference fit and realizing the installation and positioning of the conductive rod. At this time, the spring 4 is passively compressed by the thrust of the spindle 7, while the carbon brush 1 is continuously and stably contacted with the spindle 7 by the counterforce of the spring 4.

[0033] No installation space needs to be reserved inside the machine body; the conductive rod can achieve shaft current conduction by installation. The charge conduction path from carbon brush 1 to brush braid 12, then to brush holder 2 and brush holder mounting base 3, is a tight metal-to-metal contact connection, effectively reducing contact resistance and improving motor life. The conductive rod does not need to be fixed to the machine housing bolts, eliminating additional installation steps; installation can be completed in one press-fit, improving production efficiency.

[0034] The above description is merely a preferred embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. A low-impedance axially conductive rod, characterized in that, The conductive rod is mounted on the motor housing (6) with a blind hole (61). It includes a carbon brush (1), a brush holder (2), a brush holder fixing seat (3), and a spring (4). The carbon brush (1) is mounted on one end of the inner cavity of the brush holder (2). The carbon brush (1) is connected to the other end of the brush holder (2) through a brush braid (12). The spring (4) is mounted in the inner cavity of the brush holder (2) and supports the carbon brush (1) outward. The outer periphery of the other end of the brush holder (2) is embedded in the brush holder fixing seat (3) and connected and fixed thereto. A cylindrical boss is provided on one end of the brush holder fixing seat (3). The brush holder fixing seat (3) is embedded in the blind hole (61) of the housing through the boss, and the outer periphery of the boss is press-fitted with the inner wall of the blind hole (61) of the housing to realize the installation and positioning of the conductive rod.

2. The low-impedance axial conductive rod as described in claim 1, characterized in that, The outer periphery of the brush holder fixing seat (3) is cylindrical, and the end face of the brush holder fixing seat (3) near the boss forms a flange face (32), which is attached to the surface of the motor housing.

3. The low-impedance axial conductive rod as described in claim 1, characterized in that, The brush holder (2) and the brush holder fixing seat (3) are interference-fitted to achieve connection and fixation between the brush holder (2) and the brush holder fixing seat (3).

4. The low-impedance axial conductive rod as described in claim 1, characterized in that, The brush holder fixing seat (3) has a screw hole on its side and a set screw (8) is threadedly connected to it. One end of the set screw (8) presses against the brush holder (2) for positioning, so as to connect and fix the brush holder (2) to the brush holder fixing seat (3).

5. A low-impedance axial conductive rod as described in claim 1, characterized in that, The inner cavity of the brush holder (2) has a square cross-section at one end and a circular cross-section at the other end. The square cross-section cavity at one end of the brush holder (2) is used to accommodate the carbon brush (1), and the circular cross-section cavity at the other end of the brush holder (2) is used to accommodate the spring (4).

6. A low-impedance axial conductive rod as described in claim 1, characterized in that, The brush holder (2) has a central hole (23) at one end for accommodating the carbon brush (1) braided wire (12).

7. A low-impedance axial conductive rod as described in claim 6, characterized in that, The carbon brush (1) is fixedly connected to the brush braid (12) and the brush holder (2) by solder (5), riveting or fusion fixing.

8. A low-impedance axial conductive rod as described in claim 1, characterized in that, The spring (4) is preferably a cylindrical helical compression spring. The two ends of the spring (4) are in contact with the end face of the carbon brush (1) and the inner wall of one end of the brush holder (2), respectively. The center of the spring (4) accommodates the movement of the brush braid (12), so that after the conductive rod is installed with the housing, the spring (4) pushes the carbon brush (1) to maintain stable contact with the axial end face of the main shaft (7).

Images