JPS59153437A - Motor - Google Patents

Abstract

PURPOSE:To reduce the number of parts in a motor by setting the distance from the axial inner surface of an end frame to the end face of a yoke to a value longer than that from the bottom of a brush holder to the end face of the yoke, thereby reducing the load applied to the holder. CONSTITUTION:The distance from the axial inner surface of an end frame 7 to the end face of a yoke 5, with which a brush holder 8 is contacted, is set to a value longer than that from the bottom of a brush holder 8 to the end face of the yoke 5, with which the end face of the holder 8 is contacted. The load applied to the holder 8 becomes the difference obtained by subtracting the pressure of the entirety by the force required to deform the frame 7.

Description

[Detailed description of the invention] The present invention relates to the structure of mounting a motor brush holder.

The weight of the yoke accounts for 10% to 20% of the total weight of the motor, but in order to meet the demand for weight reduction, it is effective to reduce the size of the yoke to the minimum required for forming the magnetic circuit. It is a method. Accordingly, the field coil wound around the yoke largely protrudes in the axial direction from the axial end face of the yoke.

On the other hand, the two commonly used methods of fixing the brush holder are fixing the brush holder to the end frame with screws, etc., and clamping the brush holder between the end frame and the yoke end surface. In addition to the problem of water intrusion into the motor through the screw fixing part, there is also the disadvantage of high cost due to the process of drilling screw holes in the brush holder and the use of screws. In order to avoid these problems and disadvantages, if the latter method, in which the brush holder is held between the end frame and the yoke end face, is adopted, the field coil protrudes largely from the yoke end face. In addition to complicating the clamping structure, there are two joint surfaces, one between the yoke and the brush holder, and the other between the brush holder and the end frame, which prevents water from entering the motor from the outside. In terms of problems, it is disadvantageous compared to the case where there is a joint surface only between the yoke and the end frame, and furthermore, when using a resin brush holder, it is difficult to withstand the tightening force δ of the through bolt. [The problem is that it is extremely difficult to do so.

The present invention employs a structure in which a brush holder is held between an end frame and a yoke, and is intended to solve the above-mentioned problems.

In other words, before the through bolt is tightened and fixed, the distance from the place where the brush holder end face abuts on the yoke end face to the axial inner surface of the end frame is longer than the distance from the place where the brush holder end face abuts on the yoke end face to the bottom face of the end frame side of the brush holder. The distance is large, and when the through bolt is tightened and fixed, the end frame deforms toward the yoke, and the brush holder is sandwiched and fixed between the yoke end face and the inner surface in the axial direction of the end frame.

The present invention will be described below with reference to embodiments of a starter. 1st
The figure is a sectional view of the starter. 1 is an armature, and one end of its shaft 2 is pivotally supported by a maggot 3. A stator 4 surrounding the armature 1 is composed of a yoke 5 and a feed coil 6 wound around the yoke 5. The field coil 6 protrudes from the axial end face of the yoke 5 in the axial direction. Figure 2 shows the yoke 5 and end frame 7.
FIG. The end face of the yoke 5 is two-stage, with a first end face 5a that comes into contact with the end face 7a of the end frame 7 provided in an outer annular shape, and a second end face 5b that is radially larger than the first end face 5a. It is located inward and protrudes toward the end frame 7 side. The end frame 7 has a hole 7C through which the through bolt 9 passes through the axial inner surface 7b in which the brush holder 8 is disposed, and the distance from the second end surface 5b of the yoke 5 to the axial inner surface 7b is 11. . FIG. 3 shows a plan view of the brush holder 8. The brush holder 8 has a hole in the center through which the shaft 2 of the armature 1 passes, and has an annular main body 8b with a plurality of brush holding boxes 8a opened toward the hole on one side, and a ring-shaped main body 8b that protrudes outward from the main body 8b. provided leg 8
It has C. This leg 8C protrudes to the same side as the brush holding box 8a and has a slope as shown in FIG. A penetrating hole 8d is provided. The bottom surface 8f of the brush holder 8 on the end frame side contacts the axial inner surface 7b of the end frame 7, and the outer diameter of the leg 8C has an outer diameter such that the radial outer surface of the leg 8C closely contacts the inner surface of the cylindrical portion of the end frame 7.

The distance M12 from the end surface 8e to the bottom surface 8f is the distance MI+
The through bolts 9 fix the end frame 7 and the yoke 5 of the stator 4 to the housing 3.

Next, the operation of the above configuration will be explained. Figure 5 shows the end face 7 of the end frame 7 with the through bolt tightened in the previous state.
a is in contact with the first end surface 5a of the yoke 5, an end surface 8e of the brush holder 8 is in contact with the second end surface 5b of the yoke 5, and the outer side of the leg 8C is in close contact with the cylindrical portion of the end frame 7. . Moreover, since the distance β1 is set larger than the distance β2, the bottom surface 8f and the axial inner surface 7b of the end frame 7
There is a little gap between them. The through bolt 9 passes through both the hole 7C of the end frame 7 and the hole 8d of the brush holder 8. In this state, when the end frame 7 and the yoke 5 of the stator 4 are tightened to the housing 3 with the through bolts 9 to a predetermined torque value, the axial inner surface 7b around the hole 70 of the end frame 7 is deformed toward the yoke 5, and the brush holder 8
The brush holder 8 is held between the yoke 5 and the end frame 7 by coming into contact with the bottom surface 8f of the brush holder 8.

The pressure that clamps this brush holder 8 is applied to the end frame 7.
This is the value obtained by subtracting the force required to deform the axial inner surface 7b from the overall pressure, and the brush holder 8 bears part of the overall pressure. Therefore, even if the brush holder 8 is made of resin, it can sufficiently withstand pressure. Furthermore, as an example, the diameter is 801m.
In the case of a brush holder, the distance is 1. and the distance 12 (j
! +ff2) is preferably about 0.4 to 0.8 tm.

As another embodiment of the present invention, the end surfaces 5a and 5b of the yoke 5 may be formed in one piece as shown in FIG.

Further, the brush holder 8 can be made of resin, and motors other than scooters can also be used.

As described above, according to the present invention, the distance from the axial inner surface of the end frame to the yoke end surface that the brush holder contacts is set to be larger than the distance from the bottom of the brush boulder to the yoke end surface that the brush holder end surface contacts. Therefore, the load on the brush holder is equal to the total pressure minus the force required to deform the end frame, making it easy to design a resin brush holder. Furthermore, costs are reduced by reducing the number of parts and assembly man-hours, and since the only joints exposed to the outside are the end faces of the yoke and end frame, this has the advantage of being advantageous in preventing water intrusion. .

[Brief explanation of the drawing]

Fig. 1 is a partial sectional view of a starter embodying the present invention;
The figure is a cross-sectional view of the joint between the yoke and the end frame, Figure 3 is a plan view of the brush holder, Figure 4 is a cross-sectional view of the brush holder in Figure 3, and Figure 5 is the joint between the yoke and the end frame when assembled. FIG. 6 is a cross-sectional view of another embodiment of the present invention. 5... Yoke, 5a... First end surface, 5b... Second end surface, 7... End frame, 7a... End surface,
7b...Axially inner surface, 8...Brush holder, 8C.
...Leg, 8e...end surface, 8f...bottom surface. Representative Patent Attorney Takashi Okabe Figure 3 8A Figure 5 Figure 4C Figure 6

Claims (1)

[Claims] a rotating armature; a yoke surrounding the armature; an end frame that pivotally supports one end of the shaft of the armature and contacts an end surface of the yoke; In the motor, the motor has a brush holder to which a brush that slides is fixed, and a through bolt that connects and tightens and fixes the yoke end face and the end frame end face with the brush holder disposed in the end frame. The distance from the place where the brush holder end face abuts on the yoke end face to the bottom face of the end frame of the brush holder is longer than the distance from the place where the brush holder end face abuts on the yoke end face to the bottom face on the end frame side before the through bolt is tightened and fixed. The distance to the axial inner surface of the end frame is large, and when the Thrupol I is tightened and fixed, the end frame deforms toward the cork side and the brush holder is sandwiched and fixed between the yoke and the axial inner surface of the end frame. A motor with a structure that