阅读说明：本技术 一种牵引电机的轴电压接地保护结构 (Shaft voltage grounding protection structure of traction motor ) 是由 李广 李鹏 郭岚岚 于 2019-10-12 设计创作，主要内容包括：本发明属于机电设备安全保护领域，尤其涉及电机轴接地结构，具体为一种牵引电机的轴电压接地保护结构。一种牵引电机的轴电压接地保护结构，包括测速齿轮、齿轮罩、齿轮罩盖板、接地环，测速齿轮安装在电机转轴的非传动端端部，齿轮罩安装在机座外壳上，齿轮罩盖板安装在齿轮罩上，接地环安装在齿轮罩盖板内侧，接地环和测速齿轮接触，所述电机转轴、机座外壳通过测速齿轮、接地环、齿轮罩盖板、齿轮罩连接。使之同时保持零电势，无法形成电流回路，从而避免轴电压、轴电流产生。(The invention belongs to the field of safety protection of electromechanical equipment, and particularly relates to a motor shaft grounding structure, in particular to a shaft voltage grounding protection structure of a traction motor. The utility model provides a traction motor's axle voltage ground protection structure, includes speed measuring gear, gear guard apron, ground ring, and speed measuring gear installs at motor shaft's non-transmission end tip, and the gear guard is installed on the frame shell, and gear guard apron is installed on the gear guard, and ground ring installs at gear guard apron inboard, ground ring and the contact of speed measuring gear, motor shaft, frame shell are connected through speed measuring gear, ground ring, gear guard apron, gear guard. The device can keep zero potential at the same time, and a current loop can not be formed, thereby avoiding the generation of shaft voltage and shaft current.)

1. The utility model provides a traction motor's axle voltage ground protection structure, its characterized in that is including gear (1) tests the speed, gear guard (4), gear guard apron (3), ground ring (2), and the non-transmission end tip at motor shaft is installed in gear (1) tests the speed, and gear guard (4) are installed on the frame shell, and gear guard apron (3) are installed on gear guard (4), and ground ring (2) are installed in gear guard apron (3) inboard, and ground ring (2) and gear (1) that tests the speed contact, motor shaft (6), frame shell (5) are connected through gear, ground ring, gear guard apron, gear guard that tests the speed.

2. The shaft voltage ground protection structure of the traction motor according to claim 1, wherein the inner ring of the ground ring is provided with a conductive fiber (7) which extends, and the conductive fiber (7) is contacted with the speed measuring gear (1).

3. The shaft voltage ground protection structure of a traction motor according to claim 1 or 2, characterized in that the housing (5) is connected to the gear cover (4) by conductive metal bolts, and the gear cover is made of cast iron.

4. The shaft voltage ground protection structure of the traction motor according to claim 1 or 2, characterized in that the gear cover (4) is connected with the gear cover plate (3) through a conductive metal bolt, and the gear cover plate (3) is made of stainless steel.

5. The shaft voltage ground protection structure of the traction motor according to claim 1 or 2, characterized in that the ground ring (2) is cold-pressed on the inner side of the gear cover plate (3), and the ground ring (2) is made of brass.

6. The shaft voltage ground protection structure of the traction motor according to claim 1 or 2, characterized in that the speed gear (1) is sleeved at the non-transmission end of the motor rotation shaft and fastened through a conductive metal bolt, and the speed gear is made of forged steel.

7. The shaft voltage ground protection structure of the traction motor according to claim 2, wherein the speed measuring gear (1) has an annular structure extending from the outside, the annular structure of the speed measuring gear is in clearance fit with the inner ring of the grounding ring (2), and the inner ring of the grounding ring (2) is in contact with the annular structure of the speed measuring gear through the conductive fiber.

Technical Field

The invention belongs to the field of safety protection of electromechanical equipment, and particularly relates to a motor shaft grounding structure, in particular to a shaft voltage grounding protection structure of a traction motor.

Background

For inverter-powered traction motors, the generation of shaft voltage is unavoidable. The generation of shaft voltage, which breaks down the lubricating oil film on the surface of the bearing and simultaneously the lubricating oil is electrolyzed, resulting in the reduction of the performance of the lubricating oil; after the lubricating oil is broken down, extremely high current density is generated on a tiny metal surface of a bearing raceway, extremely high heat is generated instantly, and the bearing is subjected to electric corrosion. Along with the increase of the running time of the motor, the bearing electrolytic corrosion condition is aggravated, washboard lines are formed on the surface of the rolling body, and finally the bearing is ineffective due to factors such as overlarge clearance, overlarge vibration, overhigh temperature rise and the like. The service life of the bearing is seriously damaged, the motor is in failure, and the normal running of the vehicle is influenced; even axle seizing causes vehicle damage and people death, which not only affects the safety of railway transportation, but also causes great economic loss to the country and society.

Therefore, the following two methods are generally adopted to prevent the bearing failure of the motor caused by the shaft voltage when the motor is designed and installed:

one is to adopt the bearing that bearing inner race surface or inner circle internal surface have insulating coating to isolated or reduce the axle current that axle voltage formed, avoid the bearing inner and outer lane, roller, the damage that the holder caused because of the galvanic corrosion. However, the problem is that the use of the insulated bearing still can not completely avoid the electric corrosion fault of the bearing, so that the service life of the bearing can not meet the operating requirement of the vehicle.

And secondly, the two ends of the rotating shaft of the motor are additionally provided with grounding devices, and a carbon brush is arranged on a machine base of the motor, so that the shaft current is short-circuited through the grounding devices, the carbon brush and the machine base, and the current is prevented from flowing through the bearing to protect the bearing. But the use on the track traffic vehicle traction motor is often difficult to realize due to limited space.

There is a grounding structure (CN 103580390 a) for reducing shaft voltage of doubly-fed wind generator, as shown in fig. 1. The wind driven generator mainly comprises a shaft extension end-connected shaft carbon brush 8, a machine base shell 5 and a non-shaft extension end-connected shaft carbon brush 9, the three are sequentially connected with an electric connecting wire 10 through a conductive metal bolt, the machine base shell 5 is fixed on a motor foundation 11, and the machine base shell is enabled to simultaneously keep zero potential and not form a current loop, so that the generation of shaft voltage is avoided.

However, the above-described grounding structure for reducing the shaft voltage has the following disadvantages:

(1) the grounding device adopted by the technology is installed on two sides of a transmission end and a non-transmission end of a motor, occupies a large space, is used on a traction motor of a rail transit vehicle, and is narrow in application range because the space cannot be installed due to the limitation of the gauge.

(2) The grounding device is contacted with the rotating shaft through the carbon brush, so that mechanical abrasion is increased, regular maintenance is required, and the failure rate is high.

(3) The main body of the grounding structure is exposed and leaked, impurities such as wind, sand, rain and snow, lubricating oil, detergent and the like are always polluted in the operating condition of the motor, the contact parts of the grounding device and the carbon brush with the rotating shaft are easy to damage and lose efficacy, and the reliability of the product is low.

(4) After the carbon brush of the shaft extension end connection shaft is damaged in the technology, the carbon brush cannot be replaced on line, time and labor are consumed, and the maintainability is poor.

Disclosure of Invention

The invention provides a motor shaft voltage grounding structure capable of being replaced on line, belongs to the field of electromechanical equipment safety protection, and is suitable for alternating current motors, in particular to alternating current motors used by rail vehicles such as subways. The bearing protection device is used for solving the defects of the prior art that the grounding device is exposed, the grounding device is difficult to replace, the maintainability is poor, the space utilization rate is low, the product reliability is low and the like, effectively solving the problems of bearing damage and failure caused by shaft voltage from the source, prolonging the service life of the bearing, improving the reliability of a motor product, simultaneously having the functions of grounding device protection and online replacement, and being convenient and efficient to maintain.

The invention is realized by adopting the following technical scheme: the utility model provides a traction motor's axle voltage ground protection structure, includes speed measuring gear, gear guard apron, ground ring, and speed measuring gear installs at motor shaft's non-transmission end tip, and the gear guard is installed on the frame shell, and gear guard apron is installed on the gear guard, and ground ring installs at gear guard apron inboard, ground ring and the contact of speed measuring gear, motor shaft, frame shell are connected through speed measuring gear, ground ring, gear guard apron, gear guard. The device can keep zero potential at the same time, and a current loop can not be formed, thereby avoiding the generation of shaft voltage and shaft current.

Furthermore, the inner ring of the grounding ring is provided with extended conductive fibers which are in contact with the speed measuring gear.

Furthermore, the engine base shell is connected with the gear cover through a conductive metal bolt, the engine base shell can be detached on line, and the gear cover is made of cast iron.

Furthermore, the gear cover is connected with the gear cover plate through conductive metal bolts, and the gear cover plate is made of stainless steel.

Further, the ground ring is cold-pressed on the inner side of the cover plate of the gear cover and is made of brass.

Furthermore, the speed measuring gear is sleeved at the non-transmission end of the motor rotating shaft and is fastened through a conductive metal bolt, and the speed measuring gear is made of forged steel.

Furthermore, an annular structure extends out of the outer side of the speed measuring gear, the annular structure of the speed measuring gear is in clearance fit with the inner ring of the grounding ring, and the inner ring of the grounding ring is in contact with the annular structure of the speed measuring gear through conductive fibers.

The invention has simple operation, reasonable structure and obvious effect, and fundamentally inhibits the formation of the shaft voltage. The annular protruding structure on the speed measuring gear can improve the space utilization rate of the device and avoid the shaft surface abrasion caused by the direct contact of the grounding ring and the rotating shaft; in addition, the gear cover plate structure that can dismantle on line can effectively protect the ground ring structure not influenced by motor operational environment, and the reliability is high, and online change, maintenance are convenient high-efficient.

Drawings

Fig. 1 is a schematic diagram of a conventional grounding structure of a motor.

Fig. 2 is a schematic diagram of the structure of the motor shaft voltage protection device which can be replaced on line.

Fig. 3 is a partially enlarged view of a portion a in fig. 2.

Wherein: 1-a speed measuring gear; 2-a ground ring; 3-a gear cover plate; 4-gear cover; 5-a frame shell; 6-a motor rotating shaft; 7-wear resistant conductive fibers; 8-shaft extension end connection shaft carbon brush; 9-non-shaft extension end connection shaft carbon brush; 10-electrical connection lines; 11-motor base.

Detailed Description

As shown in fig. 2 and 3, the speed measuring device comprises a speed measuring gear 1, a grounding ring 2, a gear cover plate 3 and a gear cover 4, wherein the speed measuring gear 1 is installed at the end part of the non-transmission end of a motor rotating shaft 6, the gear cover 4 is installed on a machine base shell 5, the gear cover plate 3 is installed on the gear cover 4, the grounding ring 2 is installed on the inner side of the gear cover plate 3, and the machine base shell 5 is fixed on a train.

The motor base shell 5 and the motor rotating shaft 6 are connected with the grounding ring 2, the gear cover plate 3 and the gear cover 4 through the annular structure extending out of the speed measuring gear 1, so that the motor base shell and the motor rotating shaft can keep zero potential at the same time, a current loop cannot be formed, and the generation of shaft voltage and shaft current is avoided.

The engine base shell 5 is connected with the gear cover 4 through a conductive metal bolt.

The gear cover 4 is connected with the gear cover plate 3 through a conductive metal bolt and can be detached on line.

Ground ring 2 colds pressing 3 inboards at the gear cover apron, gear cover apron 3 can protect ground ring 2 not receive the influence of debris such as online operational environment apoplexy, sand, rain, snow, dust, rubble, when changing ground ring 2 on line simultaneously, do not need the motor to fall the car and disintegrate, take off gear cover apron 3, take out ground ring 2 can.

The speed measuring gear 1 is sleeved on the motor rotating shaft 6 and fastened through a conductive metal bolt.

Ground ring 2 and motor shaft 6 rely on the annular structure that stretches out on the gear that tests the speed 1 to switch on, effectively utilize the space between gear and the gear guard 4 that tests the speed, avoided ground ring 2 directly to put through with motor shaft 6, promote space utilization greatly.

The inner ring of the grounding ring 2 is provided with the extended wear-resistant conductive fiber 7, so that the speed measuring gear 1 can be well contacted with the grounding ring 2 in the running process of the motor.