CN201113686Y - Motor shaft grounding thread structure - Google Patents

Abstract

A threaded structure for grounding the shaft of an electric motor, wherein a mandrel that can be driven to rotate is provided inside the outer shell of the electric motor; the circumferential surface of the tail end of the mandrel is provided with at least one section of fine thread structure; a grounding carbon brush device is provided on the side of the fine thread structure, and is provided with a carbon brush, a hollow positioning body for the carbon brush to be sleeved, and a spring provided in the hollow positioning body for pushing the carbon brush so that its front end surface is against the fine thread structure. The utility model replaces surface contact with line contact, which greatly eliminates friction heat and the generation of oxygen film during rotation, removes carbon particles, copper powder, etc. generated by friction on the surface of the carbon brush, and keeps the surface of the carbon brush clean and protected forever. Therefore, the contact resistance between the slip ring or shaft and the carbon brush can be kept stable, and the wear of the carbon brush can be further reduced.

Description

Threaded construction for motor shaft grounding

technical field

The utility model relates to an electric motor, in particular to a threaded structure for the grounding of the electric motor shaft.

Background technique

The structure of a general motor 10 is shown in FIG. 1 , including: an outer casing 11 , a stator 12 , a rotor 13 , a spindle 14 that can be driven to rotate, and a ball bearing 15 supporting the spindle 14 . When these motors 10 are in use, due to the unbalanced magnetic circuit, external voltage (such as the PWM voltage of the AC motor inverter or the DC motor speed controller), the shaft magnetization effect, and the electrostatic induction (such as the static electricity generated by the pulley 16 and the belt 161) and so on to generate shaft voltage.

This voltage will cause the so-called axial current to be generated between the inner and outer rings 152 of the ball bearing 15; when the current passes through the contact points of the balls 151 and the inner and outer rings 152, an arc ARC will be generated to form craters and washboard effect on the surface of the inner and outer ring ball raceways. ) finally caused the consequences of noise and bearing failure.

At present, there are two ways to solve the above problems, using shaft insulation and shaft grounding carbon brushes. Among them, the shaft-grounded carbon brush has the advantages of simplicity and low price, so it is often used in general motors. 17 and its rear end compress the spring 18, so that the front surface of the carbon brush 17 is in close contact with the slip ring or the shaft surface at the shaft end, forming a bypass (by-pass) of the inner and outer rings 52 of the bearing 15. Because its contact resistance is far lower than the resistance between the inner and outer rings 152 of the bearing, the shaft current will flow through the shaft tail end or the slip ring 141 and the carbon brush 17 to be grounded; therefore, the ball bearing 15 is protected and its service life is prolonged.

However, after the shaft-grounded carbon brush 17 has been used for a period of time, a black oxide film will be formed on the surface of the shaft tail end or the slip ring 141, and its composition includes oil, dust, copper powder, etc., so that the contact resistance value gradually decreases. When the resistance is greater than the resistance of the inner and outer rings 152 of the bearing 15, most of the shaft current will flow through the bearing 15, causing the protection function of the grounding carbon brush 17 to be lost.

Therefore, how to eliminate the black oxide film on the shaft surface or the slip ring 141 to keep the contact resistance value stable is the problem to be solved by the utility model.

Utility model content

The main technical problem to be solved by the utility model is to overcome the above-mentioned defects in the prior art, and provide a thread structure for grounding the motor shaft, which uses line contact instead of surface contact, and will greatly eliminate frictional heat and oxide film damage during rotation. Generated, remove the carbon and copper powder produced by friction on the surface of the carbon brush, so that the surface of the carbon brush will always be kept clean. Therefore, the contact resistance between the slip ring or the shaft and the carbon brush can be kept stable, and the wear of the carbon brush can be further reduced.

The technical scheme that the utility model solves its technical problem adopts is:

A thread structure for motor shaft grounding, characterized in that a mandrel that can be driven to rotate is provided inside the outer casing of the motor; at least a section of fine thread structure is provided on the peripheral surface of the tail end of the mandrel; a grounding carbon brush device, It is located on the side of the fine thread structure, which has a carbon brush, a hollow positioning body for the carbon brush to be nested, and a hollow positioning body for pushing the carbon brush to make its front end surface against The spring in this fine thread structure.

The aforementioned thread structure for grounding the motor shaft, wherein the fine thread structure is formed by turning the peripheral surface of a slip ring in advance, and then pressing the slip ring into and fixing it on the tail end of the mandrel.

The aforementioned thread structure for the grounding of the motor shaft, wherein the fine thread structure is formed by direct turning on the circumferential surface of the seat end of the mandrel.

In the aforementioned threaded structure for grounding of the motor shaft, a ground wire is connected to the tail end of the carbon brush.

In the aforementioned screw structure for grounding the motor shaft, the hollow positioning body is provided with a fixed piece at the bottom end, and the fixed piece is locked on the outer shell.

With the help of the current grounding feature of the above-mentioned helical wire contact, it has been successfully applied to the shaft grounding of treadmill motors.

The beneficial effect of the utility model is that it replaces the surface contact with line contact, and the generation of frictional heat and oxygen film will be largely eliminated when rotating, and the carbon and copper powder produced on the surface of the carbon brush due to friction will be removed, so that the surface of the carbon brush Always keep clean. Therefore, the contact resistance between the slip ring or the shaft and the carbon brush can be kept stable, and the wear of the carbon brush can be further reduced.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described.

Figure 1 is a structural sectional view of an existing motor

Fig. 2 is an exploded perspective view of the first embodiment of the utility model

Fig. 3 is a combined perspective view of the first embodiment of the utility model

Fig. 4 is the main structure schematic diagram of the first embodiment of the utility model

Fig. 5 is a sectional view of the 5-5 line section shown in Fig. 4

Fig. 6 is the schematic diagram of the second embodiment of the utility model

Explanation of symbols in the figure:

20 Motor 21 Outer shell

22 mandrel 23 bearings

30 slip ring 31 fine thread structure

40 Ground carbon brush device 41 Carbon brush

411 Ground wire 42 Hollow positioning body

43 spring 44 fixed piece

45 screws

Detailed ways

At first, referring to Fig. 2, shown in 3, the utility model first embodiment comprises:

An electric motor 20, it has an outer casing 21, and this outer casing 21 inside is provided with a spindle 22 that can be driven to rotate; This spindle 22 is supported by the ball bearing 23 that is located in the outer casing 21; And above-mentioned structure is The prior art of the general motor 20 is not described in detail.

The utility model is characterized in that: the tail end of the mandrel 22 protrudes from the outer shell 21, and a slip ring 30 is sleeved and fixed, and the peripheral surface of the slip ring 30 is pre-turned to form a fine thread structure 31; accordingly, the The rear end surface of the mandrel 22 has a fine thread structure.

A grounding carbon brush device 40 is located on the side of the fine thread structure 31, which has a carbon brush 41, a hollow positioning body 42 for the carbon brush 41 to be nested, and a hollow positioning body located on the hollow positioning body. Inside 42 is a spring 43 used to push the carbon brush 41 so that its end face is against the fine thread structure 31 . In addition, the carbon brush 41 includes a ground wire 411 at the end, and the ground wire 411 can pass through the bottom of the hollow positioning body 42 .

In this embodiment, a fixing piece 44 is provided at the bottom of the hollow positioning body 42 , and is locked on the outer casing 21 by a screw 45 . But it is not limited thereto, that is, the hollow positioning body 42 may not be locked on the outer casing 21 , but on a machine platform around the motor 20 (not shown in the figure). However, no matter where the hollow positioning body 42 is locked, its purpose is to position the carbon brush 41 and keep it in contact with the fine thread structure 31 all the time.

Please refer to Fig. 4 and Fig. 5 again. The utility model sets the slip ring 30 as a fine structure 31 with a non-smooth surface, and replaces the traditional surface contact with line contact. It seems to be contrary to common sense at first glance, but The inventor's long-term test results have proved that the degree of wear between the carbon brush 41 and the fine thread structure 31 is lower than that of surface contact.

And, more importantly, by using line contact instead of surface contact, the generation of frictional heat and oxide film will be greatly reduced when the slip ring 30 rotates, and the fine thread structure 31 will function as a "screw conveyor belt" when it rotates, The surface of the carbon brush 41 is removed from the carbon powder and copper powder produced by friction to keep the surface of the carbon brush 41 clean all the time, so the contact resistance between the slip ring 30 and the carbon brush 41 can be kept stable. And this effect can make the shaft current flow through the grounding carbon brush device 40 and be exported smoothly, so the ball bearing 23 can be protected and its service life can be extended.

As shown in FIG. 6 , it is a schematic view of the second embodiment of the present invention, which is that the fine thread structure 31 is directly turned on the peripheral surface of the tail end of the mandrel 22; it has the same effect as the previous embodiment.

The above is only a preferred embodiment of the utility model, and does not limit the utility model in any form. Any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the utility model, All still belong to within the scope of the technical solution of the utility model.

In summary, the utility model fully meets the needs of industrial development in terms of structural design, practicability and cost-effectiveness, and the disclosed structure also has an unprecedented innovative structure, novelty, creativity and practicability, and meets the needs of industrial development. According to the requirements of the new patent requirements, the application is filed in accordance with the law.

Claims (5)

1. the earthy helicitic texture of motor reel is characterized in that,

Be provided with an axle that can be driven in rotation in the shell body inside of motor, this axle tail end circumferential surface is provided with one section fine thread structure at least;

One ground connection carbon brush configuration is provided in a side of the side of this fine thread structure, and it possesses a carbon brush, and a hollow positioning body and that is nested with for this carbon brush is located in this hollow positioning body, makes its front end surface be resisted against the spring of this fine thread structure in order to this carbon brush of ejection.

2. the earthy helicitic texture of motor reel according to claim 1 is characterized in that described fine thread structure is in advance in a slip ring circumferential surface turning moulding, again this slip ring is pressed into and is fixed on this axle tail end and constitute.

3. the earthy helicitic texture of motor reel according to claim 1 is characterized in that described fine thread structure is in the direct turning moulding of described axle tail end circumferential surface.

4. the earthy helicitic texture of motor reel according to claim 1 is characterized in that described carbon brush tail end is connected with an earth lead.

5. the earthy helicitic texture of motor reel according to claim 1 is characterized in that described hollow positioning body is provided with a stator in the bottom, and this stator is locked on the described shell body.

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