JPS6110959A - Dc motor - Google Patents

Abstract

PURPOSE:To eliminate powder dusts in a sensor container by providing a partition wall between the container of the sensor for mechanically detecting the rotary position of a rotor, and a magnetic circuit section in the rotor and stator. CONSTITUTION:Axial ends are supported by bearing blocks Ba, Bb, and a rotor R disposed with stators Sa, Sb at the periphery is formed of a shaft 2 and a magnet secured to the shaft 2. A bearing base 8 in the block Ba has a recess 12 at the opposite side surface to the rotor R side, and a rotary position detecting sensor or the rotor R is disposed in the recess. This sensor mechanically detects, and has a rotor C mounted at the end of the shaft 2 of the rotor R, and a pair of brushes 13, 14 respectively contacted with segments 19, 20 aligned in a pair of axial directions formed on the outer periphery of the rotor C.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a DC motor, and in particular to the arrangement of a sensor for detecting the rotational position of a rotor for synchronization.

[Background Art 1 As shown in Japanese Patent Publication No. 38-11454, etc., the rotational position of the rotor cannot be detected in a non-contact manner. ”
1. For detection, it was placed near a rotor (commutator) equipped with a switching segment attached to the rotor shaft, or a magnet that forms a magnetic circuit with the stator of the rotor, for example. Dust sucked into the motor could adhere to the rotating body, causing malfunction.

[Objective of the Invention 1 The present invention has been made in view of the above points, and its purpose is to provide a sensor for mechanically detecting the rotational position of the rotor that will not malfunction due to dust, etc. To provide DC motors.

1 Disclosure of the Invention 1 The present invention provides a magnetic circuit forming portion between a stator and a rotor, a rotary body that is mounted on the shaft of the rotor, and a switching segment provided on this rotary body that slides into contact with the segment. The main feature of the present invention is that a partition wall is provided between the rotor and the accommodating part of the rotor rotating body position detection sensor consisting of a brush, and the sensor accommodating part is isolated.

The present invention will be described below based on the illustrated embodiment of a two-pole DC motor.
lB l) i: "A supported rotor R around which a stator S is arranged is composed of a shaft 2 and a magnet fixed to this shaft 2. The coupling between this magnet 1 and the shaft 2 is selected depending on the strength of the magnet 1, and if the magnet 1 is a plastic magnet, pressurized cast magnets may be gui-cast or simultaneous molding, and sintered magnets may be bonded or botted, simultaneous molding, or gui-cast. In the illustrated example, this is done by a ponting made of adhesive resin such as epoxy resin.In FIG. 3 in the figure is the bonding resin 41.
A pair of outflow prevention members are provided at both ends of the magnet 1, and by being adhesively fixed at the same time as botting, they prevent the botting resin from flowing out and also improve the dimensional accuracy of the rotor R in the axial direction. It's something I'm trying to make available.

36 is a bushing for attaching a load member such as a fan to the shaft 2.

A stator S surrounding the outer periphery of the rotor R is composed of a pair of stator blocks Sa and Sb. Both stator blocks Sa and Sb have shapes that are point symmetrical with respect to the glaze 2, and both are formed from an iron core 4 and a coil 7. Both iron cores 4 are of a laminated type, and are fixed by caulking with caulking pins 5. A groove 47 long in the axial direction of the rotor R is formed on the outer surface of both iron cores 4, a semicircular concave groove 45 is formed in the center of the opposing surface to provide a space for arranging the rotor R, and a space for arranging the filler 7 is provided on the left and right sides of the opposing surface. Recessed grooves 46° and 46 are provided respectively. The fill 7 is placed in the groove 46 into which the insulating paper 6 is inserted.Here, both coils 7 are rectangular loops with both ends of the coil 7 in the same direction. By bending it, you can create a frontal shape or square shape.
The end face shape and the side face shape are core-shaped, and both sides are arranged in two concave vortices...16, and both ends are arranged on both end faces of the iron core 4. be. Note that it is also possible to eliminate the insulating paper 6 and the caulking pin 5 and fix the iron core 4 by simultaneous molding, if this is selected carefully in relation to the production quantity.

The bearing stand block Bb disposed at one end of the rotor R frame 2 includes a bearing stand 8 having projecting pieces 48, 48 projecting from both ends in the axial direction of the rotor R, and an oil-impregnated felt (not shown).
It is composed of a bearing 9, a spring 11 that presses the bearing 9, a stop 7 and a stopper 10 that suppresses the displacement of the shaft 2 when receiving an impact load to less than the elastic limit f of the spring 11. The bearing stand block Ba of the capacity is similarly composed of a bearing stand 8 provided with protruding pieces 48, 48, an oil-impregnated felt placed on the rotor R side surface of the bearing stand 8, a bearing 9, etc. 32 in Figure 2 is the rotor R
and the bearing 9 to reduce the friction in the thrust direction
The spacer 33 is an oil spacer for preventing oil from the bearing 9 from adhering to the rotor Y, etc. The bearing pedestal 8 in this bearing pedestal block Ba has a recess 12 formed on the surface opposite to the rotor R side, and is provided with a coil terminal 17, a droplet 16, etc.
A sensor for detecting the rotational position of the rotor R is arranged at 2.

This sensor performs mechanical detection,
A rotating body C attached to the end of the shaft 2 of the rotor R, and segments 19 and 2 arranged in the axial direction of a light provided on the outer peripheral surface of the rotating body C, each pair of brushes 13 in contact with the segments 19 and 2, respectively. , 14 (・ru.

Although the segments 19 and 20 are integral and connected to each other, there are
, 20 are integrally molded with the FM resin 18, and although the segment 19 has a continuous outer circumferential surface, the segment 20 has a slit in the middle so that it is not disposed in the circumferential direction. It is divided, and furthermore, a part of the segment 20 is also cut out from the segment 19. Each brush fixed to the bearing stand 8 by an eyelet-shaped brush fixing ring 15 ] 3 and ll are formed of wire springs, and among these, the January brush 13 connected to the anode
is in contact with the outer circumferential surface of the segment 19 on the rotating body C, and the pair of brushes 1.1 to be glued on the cathode are in contact with the outer circumferential surface of the segment 20.

The two bearing blocks Ba and Bl+ are arranged in the space between the two coils 7.7 located on the outer surface of the end of the core 1 of the stator S and located 17 on the outer surface of this end. is fitted into the groove 47 on the outer surface of the iron core 4, and
Fixing bolt 31 passing through each bearing stand 8, 8 and iron core ↓
The bearing pedestal 8 in the bearing pedestal block Ba assembled with the and nut 35 and further provided with a sensor includes:
The circuit block P is removed by covering the recess 12 in which the sensor is arranged with the circuit board 29. This circuit block 1] consists of two circuit boards fixed by fitting with the boss 16 of the bearing stand 8 and heat caulking with the boss 1G, a triump 28, a rectifier stack 27, a power transistor 21, a surge absorption fund/ 22 and barista 2
3. It is composed of circuit parts such as the smoothing capacitor 26 of the power supply, and the lead wire 30 for connection to the power source and the lead wire 40 for connection to the variable resistor for speed control are drawn out. There is. The fill terminal 17 of the bearing stand Ba is directly connected to the printed circuit board 29.

Now, in the motor shown in the illustrated example having the shape r#, both ends of each coil 7 are exposed to the outside of both ends of the iron core 4, that is, in the thrust direction, or are they combined? Both ends of each coil 7 are bent in the radial direction, that is, in the lateral direction of the iron core 4, so that a portion of the iron core When the stator S is viewed from the end surface, there is a gap between the inner 5 surfaces at both ends of the fill 7 and the outer surface of the iron core 4, as shown in FIGS. 4 and 5. The end face shape of the stator S as a whole is made up of a long sword-shaped iron core 4 and a fill 2 that protrudes outward in the short direction of the iron core 4. , is approximately square in shape.

Note that the magnets in the rotor 1 are not magnetized during assembly 1ijj with the stator S, but are magnetized after they are assembled with the stator S. Assemble the magnetized rotor R to the stator S (at τ1, the magnet hits the iron core 4 due to the attractive force of 11 magnets between the magnet 1 and the iron core 4, and the magnet breaks). ”
Secondly, in view of the fact that the fitting between the shaft 2 and the bearing 9 is now difficult, there is C'. As shown in the figure, an exciting coil 56 is placed between the wound magnetizing yokes 55, and the magnet 1 is magnetized via the iron core 4.

In this case, the magnet 1 is formed in a shape almost facing the magnetic pole of the stator S, and after the magnetizing magnetic field is removed, the NS pole of the magnet 1 is in the gap between the magnetic poles of the stator S. Stop with your head facing a small place. In this state, one end of the shaft 2 is supported, and the rotating body C is press-fitted into the end of the support 2 with the outside of the iron core 4 as a reference.

If magnetization is performed after assembly in this way, it will be easier to assemble the rotor R and stator S.
Since the hermeance of the magnet increases, the demagnetization of the magnet decreases, and therefore it becomes possible to use a magnet material with a small coercive force, which is advantageous in terms of cost. Furthermore, when the rotating body C is installed as described above, the stopping position of the rotor R (
This allows the rotating body C to be moved based on the starting position), which reduces the variation in the position of the magnetic poles and the rotating body C, and makes it easier to adjust the rotating body C. .

7 to 9 show other examples of the brushes 13 and 14 in the sensor for detecting the rotational body position of the rotor R in item 1. When the brushes 13 and 14 are formed of wire springs, the rotation Since this is a point contact with the contact force (segment) 19.20 of body C, and the reliability of conduction is not very high, a U-shaped wire rod 57 is fixed by welding to the tip of each brush 13.14 made of a wire spring. Then, the tip of this wire 57 is a segment] 9, 2 (Ts 1 so that it touches l)
The reliability of conduction is increased by making multi-point contact.

1 Effect of the invention 1 As described above, in the present invention, a partition wall is provided between the housing part of the sensor that mechanically detects the rotational position of the rotor and the magnetic circuit part of the rotor and stator. , it is difficult for dust to enter the sensor accommodating portion, and the risk of malfunction of the sensor due to dust is extremely reduced.

[Brief explanation of the drawing]

Figure 1 is a perspective view of one embodiment of the present invention, Figure 2 is an exploded perspective view of the same, Figure 3 is a cutaway front view of the same, and 4V is the same 4.
Figure S is a plan view with the L-way block removed. Figure S is a cutaway plan view with the bearing stand removed. Figure 6 is a cutaway front view showing the magnetized state of Figure 2. is an exploded perspective view of an example using the first generation brush of the same type, FIG. 8 is a perspective view of the same as the above, and FIGS. 4 is the iron core, 7 is the fill, 8 is the bearing stand, 13.14
is a brush, 19, 2 (1 indicates a segment, C indicates a rotating body. Agent Patent Attorney Stone 1) Long 7 Figure 6 Figure 7 Figure 8

Claims (3)

[Claims] (1) A rotor rotational position detection sensor consisting of a magnetic circuit forming part between the stator and rotor, a rotating body attached to the shaft of the rotor, a switching segment provided on the rotating body, and a brush slidingly in contact with the segment. Between the storage section,
A DC motor characterized by having a partition wall separating the two. (2) A patent claim characterized in that the partition wall is formed of a bearing stand for supporting the rotor, and the sensor housing portion is formed as a recess covered by a circuit block in the bearing stand. A DC motor according to item 1. (3) The DC motor according to claim 1, wherein the brush is formed of a wire spring and has a multi-striped tip that contacts the segment of the rotating body.