JPS6223243Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a rotating electrical machine, particularly a rotating electrical machine such as a DC generator or a DC motor, in which a commutator is arranged and the bearing structure of a rotating shaft serving as an output shaft is a cantilever type.

FIG. 7 shows an example of this type of rotating electrical machine, in which 1 is a radial bearing fixed to the rotating electrical machine case 28, 2 is a rotating shaft supported by the bearing, 1
Reference numeral 7 denotes an iron core held integrally with the rotating shaft via an iron core holding member 18, 26 a coil wound around the iron core, and 27 a case 28 facing the iron core 17.
It is a permanent magnet that is attached and supported inside the. 9 is a commutator fixed to the rotating shaft 2, and includes a commutator piece holding member 11 made of an electrically insulating material such as resin, and a plurality of commutators arranged and held at approximately equal intervals along the outer circumference of the member. It consists of a commutator segment 10. A brush 29 is in contact with the commutator piece 10, and is attached and supported by the case 28. 8 is a thrust receiver at the end of the rotating shaft 2 on the commutator mounting side;
It is fixed to the inner surface of the case 28.

In the thrust receiver 8, as the weight of the rotor increases, the thrust force due to magnetic attraction also increases.
Even if the thrust receiver is made of wear-resistant material such as nylon, it will cause a lot of wear if it is left dry, so apply a little lubrication (lubricant such as grease) to the thrust receiver.
is necessary.

In this case, the lubricant spreads from the outer surface of the rotating shaft 2 to the end face of the commutator 9 in a diffusive manner (seepage) as shown by the arrow in FIG. The centrifugal force accompanying the rotation of the commutator 9 directly scatters onto the end face of the commutator 9 and the commutator pieces 10.
is likely to become dirty and cause poor electrical contact with the brush 29. As a preventive measure, the distance l between the thrust receiver 8 and the commutator 9 is set to be large, but this results in the shape and dimensions of the rotating electrical machine in the direction of the rotational axis to increase accordingly.

The present invention was proposed in view of the above, and is based on the overall shape and shape of this type of rotating electrical machine.
The purpose of the present invention is to reliably prevent commutator pieces from being contaminated by a lubricant applied to a thrust receiving portion over a long period of time without increasing the dimensions.

That is, in the present invention, a commutator piece holding member holding a commutator piece is fixed to a rotating shaft, and a recessed hole is formed inside one end side of the commutator piece or the commutator piece holding member between the commutator piece and the rotating shaft. an electric insulator is fixed inside the recessed hole, and extends from a thrust receiver that receives one end side of the rotating shaft toward the commutator piece holding member along the outer periphery of the rotating shaft, and the commutator piece or commutator The distal end side protrudes into the recessed hole provided with the electrical insulator of the one-piece holding member, and a cylindrical body containing a lubricant is provided at the inner bottom, between the rotating shaft and the inner periphery of the cylindrical body, A rotating electrical machine is characterized in that a gap is formed between the outer periphery of the cylindrical body and the inner periphery of the insulator.

FIG. 1 is a longitudinal sectional view of the main parts of an embodiment of the present invention. Reference numeral 12 denotes a recessed hole provided inside the commutator piece holding member 11 holding the commutator piece 10, opening at the end face on the thrust receiver 8 side and between the commutator piece holding member 11 and the rotating shaft 2. Reference numeral 21 denotes a cup-shaped electrical insulator that is adhesively fixed to the inside of this recessed hole. 15 extends from the thrust receiver 8 along the outer periphery of the rotating shaft 2 in the direction of the commutator piece holding member 11, and projects its tip end side into the recessed hole 12 in which the electrical insulator 21 of the commutator piece holding member 11 is provided. It is a cylindrical body provided in a straight line. 16 is a lubricant placed in the inner bottom of the cylinder. There are gaps between the rotating shaft 2 and the inner periphery of the cylinder 15 and between the outer periphery of the cylinder 15 and the inner periphery of the electrical insulator 21, respectively.

FIG. 2 shows another embodiment, in which a recessed hole 12 is formed inside the commutator piece 10 held by a holding member 11, and an electrical insulator 21 is placed inside the recessed hole 12.
is fixed, and the rest has the same structure as the example shown in FIG. 1 above.

Therefore, according to the present invention, in order for the lubricant 16 placed in the inner bottom of the cylinder 15 to reach the commutator piece 10 portion of the commutator 9 through diffusion (leaching), the outer circumferential surface of the rotating shaft 2 must be →The inner bottom surface of the electrical insulator 21 fixed in the recessed hole 12 on the commutator 9 side→The inner peripheral surface of the electrical insulator 21→The outer end surface of the electrical insulator 21 Therefore, in practice, the lubricant hardly reaches the commutator bar 10 portion by diffusion.

b Even if the lubricant 16 placed in the inner bottom of the cylindrical body 15 scatters due to the centrifugal force accompanying the rotation of the rotating shaft 2, since the rotating shaft 2 is surrounded by the cylindrical body 15, the scattering will not occur within the cylindrical body. Therefore, the scattered lubricant adheres directly to the inner bottom surface, inner circumferential surface, and outer end surface of the electrical insulator 21 on the commutator 9 side, and furthermore, to the commutator piece 10 portion, causing damage to these parts. is prevented from being contaminated.

c Also, even if the lubricant inside the cylinder 15 diffuses through the inner circumferential surface of the cylinder 15 to the tip side of the cylinder and wraps around to the outer circumferential side, the lubricant inside the cylinder 15 and the electric insulator 21 on the commutator 9 side is non-contact, and since the cylinder is a non-rotating member, the lubricant that has wrapped around the outer circumferential surface of the cylinder 15 will be transferred to the electrical insulator 21 etc. on the commutator 9 side by diffusion or scattering. There isn't.

d The cylindrical body 15 has a recessed hole 1 provided coaxially with the rotating shaft 2 inside the commutator piece holding member 11 as in the example in FIG. 1 or inside the commutator piece 10 as in the example in FIG.
Since the distal end side is inserted into the electric insulator 21 provided in the cylindrical body 15
By providing this, the problem of increasing the overall shape and dimensions of the rotating electric machine does not occur.

Therefore, by the effects of a to d above, it is possible to reliably prevent the commutator pieces from being contaminated by the lubricant applied to the thrust receiving portion over a long period of time without increasing the overall shape and dimensions of the rotating electric machine. It is something.

In the rotating electric machine of the present invention, it is necessary to form a concave hole 12 centered on the rotating shaft between the rotating shaft 2 at the end of the commutator and the commutator piece holding member 11 or the commutator piece 10. As the commutator 9, it is effective to use a cup-shaped commutator having a U-shaped longitudinal section.

An example of the manufacturing method of this cup-shaped commutator 9 will be explained with reference to FIGS. 3 to 6. FIG. 3 is a perspective view showing a cylindrical commutator base (hereinafter abbreviated as cylinder), in which a large number of slits 23 are made from one end of the cylinder 22 at approximately equal intervals on the circumference, as shown by chain lines. to form a large number of separation pieces 24, and each separation piece 24
is bent outward at a substantially right angle from the middle to form a riser (the flat plate may be made into the cylinder 22 by making a number of cuts at approximately equal intervals from one end of the flat plate, and then rolling this flat plate). Next, the cylinder 22 is placed in a mold (not shown) and insert molded with electrically insulating resin 11 so as to leave a space inside the cylinder.
By cutting the cylinder 22 along line Y--Y in the figure, the cylinder 22 is electrically divided into the desired number of commutator segments 10 at the slits 23 to obtain a cup-shaped commutator. FIG. 5 is a front view of this cup-shaped commutator 9. However, as it is, the slit 23 is clogged with mold insulator.
Since this is undesirable as it causes flash over, this should be removed by appropriate means. In this case, since the inside of the cylinder 22 is a space, it is easy to remove the mold insulator stuck in the slit 23. Furthermore, when the cylinder 22 is formed by rolling the plate, the cross-sectional shape of the slit 23 becomes a dish-like shape that expands outward, making it easier to remove the mold insulator.

The embodiment shown in FIG. 2 uses the cup-shaped commutator 9 manufactured above attached to the rotating shaft 2, and in this case, the electrical insulator 21 provided inside the commutator bar 10 and the commutator bar If a gap is formed between the commutator segments 10 and the upper gap g (Fig. 2), the abrasion powder of the brushes and commutator generated during use of the rotating electric machine will pass through the slit 23 between each commutator segment 10 and the upper gap g. The commutator does not move and accumulate in the slit 23, which prevents the slit from clogging, thereby extending the life of the commutator.

Since the commutator 9 manufactured by the manufacturing method shown in FIGS. 3 to 5 does not have slits in the mold part that holds the riser part 24, the mechanical strength of the commutator is high and the commutator can be bonded to the rotating shaft. Adhesive will not sometimes enter the segment slit portion and cause poor continuity. In addition, in the above manufacturing method, when the number of segments is an even number, by providing the slits for the cylinder 22 at symmetrical positions on the diameter line passing through the center of the cylinder, the slit position can be easily determined and the man-hours for segment processing can be reduced by 1/2. There is an advantage in that it can be reduced to 2.

FIG. 6 is a cross-sectional view showing the molding die for the commutator molding process shown in FIG.
35 is the hot water path provided in the medium size, and 35 is the part where the mold resin enters, and the separating piece (riser) 24 of the commutator piece metal fitting is
is clamped at the joint between the upper die 30 and the middle die 31.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of the main part of one embodiment, FIG. 2 is the same diagram of another embodiment, FIGS. 3 to 6 are explanatory diagrams of a method of manufacturing a cup-shaped commutator, and FIG. 7 8 is a vertical cross-sectional view of an example of a conventional rotary shaft cantilever type rotating electric machine, and FIG. 8 is an enlarged view of a commutator portion. 2 is a rotating shaft, 9 is a commutator, 10 is a commutator piece, 1
1 is a commutator piece holding member, 12 is a recessed hole, 15 is a cylindrical body, and 16 is a lubricant.

Claims (1)

[Scope of utility model registration request] Commutator piece holding member 1 holding commutator piece 10
1 is fixed to the rotating shaft 2, a recessed hole 12 is provided inside one end side of the commutator piece 10 or the commutator piece holding member 11 between the rotary shaft 2, and an electrically insulating member is provided inside the recessed hole 12. The body 21 is fixed, and the rotating shaft 2 is inserted from a thrust receiver 8 that receives one end side of the rotating shaft 2.
extends toward the commutator piece holding member along the outer periphery of the commutator piece 10 or the commutator piece holding member 11. is provided with a cylindrical body 15 containing a lubricant 16, and the rotating shaft 2 and the cylindrical body 15 are connected to each other.
A rotating electrical machine characterized in that a gap is formed between the inner periphery of the cylindrical body 15 and between the outer periphery of the cylindrical body 15 and the inner periphery of the insulator 21.