A motor shaft grounding device and its motor

Abstract

The present invention provides a grounding device for a motor shaft, which is used for grounding and discharging the motor shaft in a motor. The grounding device includes a fixing frame, a carbon brush, a pre-tightening mechanism and a conductive bridge. The fixing frame is connected to the grounding ring of the motor. The carbon brush is fixed to the fixing frame. The carbon brush includes a contact surface, and the contact surface abuts against the motor shaft. The pre-tightening mechanism is connected to the fixing frame, and the pre-tightening mechanism applies a pre-tightening force from the contact surface to the motor shaft. The conductive bridge is electrically connected to the carbon brush and the grounding ring of the motor respectively. The present invention also provides a motor including the grounding device for the motor shaft, which further includes a motor shaft and a grounding ring. For the electromagnetic induction current generated by the motor shaft in the present invention, it is guided to the grounding ring of the motor through the carbon brush and the conductive bridge. The carbon brush realizes a tight connection with the motor shaft through the pre-tightening mechanism, eliminating the safety hazard of the energized motor shaft. The fixing frame is made of plastic material and integrally formed. The replacement of the carbon brush is convenient. The structure has strong stability, low cost, small volume, simple structure and strong practicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of motor operation discharge, and particularly relates to a motor shaft grounding device and a motor thereof. Background Art

[0002] Motors are widely used in various industries. Especially in the field of electric vehicles, the safe operation of motors has attracted increasing attention. During the operation of a motor, the problem of capacitive interference current often occurs. In an asynchronous motor directly operated by the power supply current, the phase voltage remains balanced, and the sum of the positive and negative tensions is always zero. However, due to the electromagnetic induction effect, a certain current is generated on the rotating shaft of the motor, resulting in voltage imbalance. The voltage induced in the motor winding on the rotating shaft may cause discharge on the motor bearing, and the generated sparks corrode and accelerate the aging of the bearing grease, damaging the running surface, thereby causing damage to the bearing, gear, coupling, and the machine with additional bearings on the shaft. Eventually, the interference current will cause serious bearing or gear damage and broadband radio interference.

[0003] The current solutions generally involve installing a slip ring with a conductive brush on the motor housing to make the slip ring contact the rotating shaft. However, the manufacturing cost is high, the structure is complex, it is inconvenient to replace the carbon brush after it reaches its service life, and the contact pressure between the carbon brush and the rotating shaft is unstable. Summary of the Invention

[0004] The purpose of the present invention is to overcome the deficiencies of the above-mentioned prior art, and provide a motor shaft grounding device and a motor thereof, which overcome the problems of high manufacturing cost, complex structure, inconvenient carbon brush replacement, etc. existing in the prior art for solving the problem of capacitive interference current.

[0005] In a first aspect, the present invention provides a motor shaft grounding device for grounding and discharging the motor shaft in a motor, including a fixing frame, a carbon brush, a pre-tightening mechanism, and a conductive bridge. The fixing frame is connected to the grounding ring of the motor. The carbon brush is fixed to the fixing frame. The carbon brush includes a contact surface, and the contact surface abuts against the motor shaft. The pre-tightening mechanism is connected to the fixing frame, and the pre-tightening mechanism applies a pre-tightening force from the contact surface to the motor shaft to the carbon brush. The conductive bridge is electrically connected to the carbon brush and the grounding ring of the motor respectively.

[0006] Further, the fixing frame includes a bottom plate, a side plate, and two limiting plates. The side plate is vertically provided at the edge of the bottom plate close to the motor shaft. The two limiting plates are vertically provided on the side plate. The two limiting plates and the bottom plate enclose a receiving space. The carbon brush is limited and connected to the receiving space. At least one fixing hole is provided on the bottom plate, and the fixing hole is used to connect the grounding ring of the motor. The side plate is adapted to the arc surface of the motor shaft.

[0007] Further, the fixing bracket is made of plastic material.

[0008] Further, at least one of the fixing holes is provided with a clamping structure, the first end of the conductive bridge is clamped in the clamping structure, and the first end of the conductive bridge is electrically connected to the grounding ring of the motor.

[0009] Further, the first end of the conductive bridge is provided with a grounding piece, the grounding piece is clamped in the clamping structure, and the grounding piece is connected to the fixing hole by a bolt.

[0010] Further, a limiting gap is provided between the two limiting plates, the second end of the conductive bridge is arranged in the limiting gap, and the second end of the conductive bridge is electrically connected to the carbon brush.

[0011] Further, the accommodating space is open in the direction opposite to the side plate, and the pre-tightening mechanism is connected to the carbon brush from this opening direction.

[0012] Further, the pre-tightening mechanism is a coil spring, the coil spring is connected to the fixing bracket, and the coil spring applies a pre-tightening force pointing to the contact surface to the carbon brush from the opening of the accommodating space.

[0013] Further, two limiting posts are provided on the bottom plate, the coil spring has a "Ji"-shaped structure, the coil spring includes a force-applying part and two limiting feet, the two limiting feet are respectively arranged on both sides of the force-applying part, the limiting feet are respectively sleeved on the limiting posts, and the force-applying part abuts against the carbon brush.

[0014] In a second aspect, the present invention provides a motor, including a motor shaft grounding device as described above, and further including a motor shaft and a grounding ring, and the motor shaft is electrically connected to the grounding ring through the motor shaft grounding device.

[0015] Advantages of the present invention:

[0016] 1. The present invention provides a motor shaft grounding device and a motor thereof. For the electromagnetic induction current generated by the motor shaft, it is guided to the grounding ring of the motor through the carbon brush and the conductive bridge. The carbon brush is tightly connected to the motor shaft through the pre-tightening mechanism, eliminating the safety hazard of the motor shaft being charged.

[0017] 2. The fixing bracket is made of plastic material and integrally formed, the replacement of the carbon brush is convenient, the structural stability is strong, the cost is low, the volume is small, the structure is simple, and the practicability is strong;

[0018] 3. In the form of a coil spring, a stable pre-tightening pressure is provided within the service life of the carbon brush, ensuring the tight connection between the carbon brush and the motor shaft, which is stable and reliable. Description of the Drawings

[0019] The present invention will be further described with reference to the accompanying drawings. However, the embodiments shown in the drawings do not constitute any limitation to the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the following drawings without creative efforts.

[0020] Figure 1 It is a schematic diagram of the overall structure of a motor shaft grounding device according to Embodiment 1 from one perspective.

[0021] Figure 2 It is a schematic diagram of the overall structure of a motor shaft grounding device according to Embodiment 1 from another perspective. Detailed Embodiments

[0022] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the present invention. In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0024] Embodiment 1:

[0025] Referring to Figures 1 to 2 , Embodiment 1 provides a motor shaft grounding device for grounding and discharging the motor shaft in a motor, including a fixing frame 1, a carbon brush 2, a pre-tightening mechanism 3, and a conductive bridge 4. The fixing frame 1 is connected to the grounding ring of the motor. The carbon brush 2 is fixed to the fixing frame 1. The carbon brush 2 includes a contact surface 21, and the contact surface 21 abuts against the motor shaft. The pre-tightening mechanism 3 is connected to the fixing frame 1, and the pre-tightening mechanism 3 applies a pre-tightening force from the contact surface 21 to the motor shaft to the carbon brush 2. The conductive bridge 4 is electrically connected to the carbon brush 2 and the grounding ring of the motor respectively.

[0026] It should be noted that the motor includes a motor shaft and a grounding ring. The motor shaft rotates on its own axis, while the grounding ring remains stationary. A fixing bracket 1 is connected to the grounding ring. The fixing bracket 1 can remain stationary relative to the grounding ring or can rotate relative to it. The key point is that the conductive bridge 4 located on the fixing bracket 1 is always in conductive connection with the grounding ring. After ensuring the conductive connection between the conductive bridge 4 and the grounding ring, the conductive bridge 4 is simultaneously in conductive connection with the carbon brush 2. The carbon brush 2 is tightly connected to the motor shaft through a pre-tightening mechanism 3, thereby forming a conductive path, namely the motor shaft, the carbon brush 2, the conductive bridge 4, and the grounding ring, eliminating the safety hazard of the energized motor shaft and avoiding the adverse effects such as the generation of interference current due to the discharge of the motor shaft, which may lead to serious damage to bearings or gears.

[0027] In this embodiment, the fixing bracket 1 includes a bottom plate 11, side plates 12, and two limiting plates 13. The side plates 12 are vertically provided at the edge of the bottom plate 11 close to the motor shaft. The two limiting plates 13 are vertically provided on the side plates 12. The two limiting plates 13 and the bottom plate 11 enclose a receiving space. The carbon brush 2 is connected in a limited way in the receiving space. At least one fixing hole 14 is provided on the bottom plate 11. The fixing hole 14 is used to connect the grounding ring of the motor. The side plates 12 are adapted to the arc-shaped surface of the motor shaft, and the side plates 12 are in clearance fit with the motor shaft. From the direction of the motor shaft along its radial direction outward, that is the direction in which the limiting plates 13 extend, and also the direction in which the receiving space opens. Push the carbon brush 2 into the receiving space in the opposite direction of this direction, and achieve pressing through the pre-tightening mechanism 3.

[0028] As an implementation method, the fixing bracket 1 is made of plastic material and is integrally formed, with a small volume, strong structural stability, and convenient installation.

[0029] As an implementation method, among the multiple fixing holes 14, at least one fixing hole 14 is provided with a clamping structure 15. The first end of the conductive bridge 4 is clamped in the clamping structure 15. The first end of the conductive bridge 4 is in conductive connection with the grounding ring of the motor. Through this clamping structure 15, the clamping and limiting of the first end of the conductive bridge 4 are realized, avoiding the instability of the conductive bridge 4 during operation.

[0030] As an implementation method, a grounding piece 41 is provided at the first end of the conductive bridge 4 and is fixed by welding. The grounding piece 41 is clamped in the clamping structure 15. The clamping structure 15 includes two limiting columns 14. The limiting columns 14 clamp the grounding piece 41 in the horizontal direction. The grounding piece 41 is connected to the fixing hole 14 through a bolt, avoiding the falling off of the grounding piece 41 in the up and down directions.

[0031] As an implementation manner, a limiting gap 16 is provided between two limiting plates 13. The limiting gap 16 is located above the carbon brush 2. The distance of the limiting gap 16 corresponds to the diameter of the second end of the conductive bridge 4. The second end of the conductive bridge 4 is arranged in the limiting gap 16. The second end of the conductive bridge 4 is electrically connected to the carbon brush 2. This limiting gap 16 ensures that the second end of the conductive bridge 4 will not be displaced.

[0032] As an implementation manner, the conductive bridge 4 is a brush braid wire structure.

[0033] In this embodiment, the accommodating space opens in the direction opposite to the side plate 12. This opening direction is the direction radially outward along the motor shaft. The pre-tightening mechanism 3 is connected to the carbon brush 2 from this opening direction. The direction of the applied pre-tightening force is towards the motor shaft.

[0034] As an implementation manner, the pre-tightening mechanism 3 is a coil spring 30. The coil spring 30 is connected to the fixing frame 1. The coil spring 30 applies a pre-tightening force towards the contact surface 21 to the carbon brush 2 from the opening of the accommodating space.

[0035] As an implementation manner, two limiting posts 14 are provided on the bottom plate 11. The coil spring 30 has a structure similar to the Chinese character "ji". The coil spring 30 includes a force-applying part 31 and two limiting feet 32. The two limiting feet 32 are respectively arranged on both sides of the force-applying part 31. The limiting feet 32 are respectively sleeved on the limiting posts 14. The force-applying part 31 abuts against the carbon brush 2. Under the action of the limiting posts 14, the two limiting feet 32 generate a certain torque. The coil spring 30 in a stretched state applies a pre-tightening force to the carbon brush 2 through the force-applying part 31, so that the carbon brush 2 tightly adheres to the motor shaft and maintains an electrical connection state.

[0036] Embodiment 2:

[0037] Embodiment 2 provides a motor, including a motor shaft grounding device in Embodiment 1, and further including a motor shaft and a grounding ring. The motor shaft is electrically connected to the grounding ring through the motor shaft grounding device. The grounding ring and the motor shaft grounding device are both inside the motor housing.

[0038] Compared with the prior art, the present invention provides a motor shaft grounding device and its motor. For the electromagnetic induction current generated by the motor shaft, it is guided to the grounding ring of the motor through the carbon brush 2 and the conductive bridge 4. The carbon brush 2 is tightly connected to the motor shaft through the pre-tightening mechanism 3, eliminating the safety hazard of the charged motor shaft.

[0039] The fixing frame 1 is made of plastic material and integrally formed. The carbon brush 2 is convenient to replace, has strong structural stability, low cost, small volume, simple structure, and strong practicability;

[0040] In the form of the coil spring 30, a stable pre-tightening pressure is provided within the service life of the carbon brush 2 to ensure the tight connection between the carbon brush 2 and the motor shaft, which is stable and reliable.

[0041] Finally, it should be emphasized that the present invention is not limited to the above embodiments. The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A motor shaft grounding device for grounding and discharging the motor shaft in a motor, Characterized in that, It includes a fixing frame, a carbon brush, a pre-tightening mechanism and a conductive bridge. The fixing frame is connected to the grounding ring of the motor. The carbon brush is fixed to the fixing frame. The carbon brush includes a contact surface which abuts against the motor shaft. The pre-tightening mechanism is connected to the fixing frame and applies a pre-tightening force from the contact surface to the motor shaft to the carbon brush. The conductive bridge is electrically connected to the carbon brush and the grounding ring of the motor respectively; The fixing frame includes a bottom plate, a side plate and two limiting plates. The side plate is vertically arranged at the edge of the bottom plate close to the motor shaft. The two limiting plates are vertically arranged on the side plate. The two limiting plates and the bottom plate enclose a receiving space. The carbon brush is limited and connected in the receiving space. At least one fixing hole is provided on the bottom plate, and the fixing hole is used for connecting the grounding ring of the motor. The side plate is adapted to the arc surface of the motor shaft.

2. A motor shaft grounding device according to claim 1, Characterized in that, The fixing frame is made of plastic material.

3. A motor shaft grounding device according to any one of claims 1 to 2, Characterized in that, At least one of the fixing holes is provided with a clamping structure. The first end of the conductive bridge is clamped in the clamping structure, and the first end of the conductive bridge is electrically connected to the grounding ring of the motor.

4. A motor shaft grounding device according to claim 3, Characterized in that, The first end of the conductive bridge is provided with a grounding piece, and the grounding piece is clamped in the clamping structure. The grounding piece is connected to the fixing hole by a bolt.

5. A motor shaft grounding device according to claim 3, Characterized in that, A limiting gap is provided between the two limiting plates. The second end of the conductive bridge is arranged in the limiting gap, and the second end of the conductive bridge is electrically connected to the carbon brush.

6. A motor shaft grounding device according to claim 4 or 5, Characterized in that, The receiving space is open in the direction opposite to the side plate, and the pre-tightening mechanism connects the carbon brush from this opening direction.

7. A motor shaft grounding device according to claim 6, Characterized in that, The pre-tightening mechanism is a coil spring. The coil spring is connected to the fixing frame and applies a pre-tightening force pointing to the contact surface from the opening of the receiving space to the carbon brush.

8. A motor shaft grounding device according to claim 7, Characterized in that, Two limiting columns are provided on the bottom plate. The coil spring has a "Ji"-shaped structure. The coil spring includes a force-applying part and two limiting feet. The two limiting feet are respectively arranged on both sides of the force-applying part. The limiting feet are respectively sleeved on the limiting columns, and the force-applying part abuts against the carbon brush.

9. A motor, Characterized in that, It includes a motor shaft grounding device according to any one of claims 1 to 8, and also includes a motor shaft and a grounding ring. The motor shaft is electrically connected to the grounding ring through the motor shaft grounding device.

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