JP6027449B2 - Electric motor - Google Patents

Description

  The present invention relates to an electric motor including a commutator (an element called a commutator or a commutator) and a brush, and more particularly to an electric motor suitable for use as a starter motor of a two-wheeled vehicle.

  Among these types of electric motors, there is one in which a terminal for supplying power to the brush from the outside is provided through a peripheral wall of the motor casing via an insulator. In this type of conventional electric motor, when a terminal penetrated through the peripheral wall of the motor casing is firmly fixed to the motor casing using bolts and nuts provided outside the motor casing, when an external force is applied Also prevents the terminal from being removed from the motor casing. For example, in the electric motor described in Patent Document 1, the terminal is fixed to the motor casing by screwing a nut from the outside of the motor casing to a male screw portion formed in the terminal (see, for example, Patent Document 1). .

JP 2010-124531 A

  However, when the terminal is prevented from coming off with bolts and nuts provided outside the motor casing as in the past, the external dimensions of the motor will increase by the amount of bolts and nuts, and the terminal will be installed in the vehicle. However, there is a problem that the part becomes an obstacle and the number of parts increases as much as bolts and nuts are used.

  Therefore, there has been a request to replace the terminal with a simpler means instead of using bolts and nuts. However, when replacing the fixing of the terminal with a simple means, it has become necessary to more reliably guarantee from the viewpoint of fail-safe that the terminal is not likely to be detached from the motor casing.

  The present invention has been made in view of the above circumstances, and can reliably fix the terminal to the motor casing by simple means while reliably preventing the terminal from coming off, thereby reducing the external dimensions of the motor. It is an object of the present invention to provide an electric motor that enables this.

In order to solve the above-mentioned problems, the invention described in claim 1 is a motor casing constituting a stator, a rotor rotatably supported by the motor casing, a rotor provided on the rotor, and supplied to the coil of the rotor. A commutator that switches the direction of the generated current, a brush that slidably contacts the commutator and allows current to flow through the commutator, and from the outside of the motor casing to the inside of the brush holder via a through hole in the peripheral wall of the motor casing And a brush tail joined to the terminal and the brush and electrically connecting the terminal and the brush to each other, and a resin brush holder fixed to the inside of the motor casing. The terminal is received from one end side in the axial direction at a position corresponding to the terminal on the peripheral wall of the holder. Of the gap between the edge of the brush holder slit and the terminal, the gap corresponding to the joint between the pigtail and the terminal is smaller than the wire diameter of the pigtail. It is characterized by being set.
With this configuration, even when an external force is applied and the terminal is about to come out of the motor casing, it is possible to prevent the terminal from coming off by stopping the pigtail against the wall surface of the brush holder around the slit.

The invention described in claim 2 is characterized in that the length of the pigtail from the brush to the terminal is set shorter than the length from the brush to the through hole of the motor casing via the slit of the brush holder. And
With this configuration, it is possible to more reliably prevent the terminal from coming off from the motor casing.

According to a third aspect of the present invention, a terminal and a resin terminal holder that holds the terminal in a penetrating state are formed as an integral part terminal unit by insert molding, and the terminal unit is inserted into the through hole of the motor casing. The terminal is fixed to the motor casing through the terminal holder by press-fitting and fixing the terminal holder.
With this configuration, it is not necessary to use screws or the like for fixing the terminal to the motor casing, and the assemblability is improved.

  According to the invention described in claim 1, since the gap between the periphery of the slit of the brush holder and the terminal is set smaller than the wire diameter of the pigtail joined to the terminal, an external force is applied. Even when the terminal is about to come out of the motor casing, it is possible to prevent the terminal from coming off by stopping the pigtail against the wall surface of the brush holder around the slit. Therefore, it is possible to increase the reliability of fail-safe against terminal disconnection, thereby greatly reducing the possibility that the brush or pigtail is exposed to the outside due to some trouble. In addition, since the part that guarantees terminal removal is provided inside the motor casing, there is no need to provide a strong terminal fixing structure such as screwing outside the motor casing. Can be simplified, thereby contributing to a reduction in occupied space when the electric motor is installed in the vehicle. In addition, since the brush holder has a function of preventing the terminal from coming off, the number of peripheral parts around the terminal can be reduced, which can contribute to cost reduction.

  According to the invention described in claim 2, by providing a specific restriction on the length of the pigtail, it is possible to more reliably prevent the terminal from coming off from the motor casing. Therefore, the reliability of fail safe can be further increased.

  According to the invention described in claim 3, the terminal and the resin-made terminal holder are formed as an integral part terminal unit by insert molding, and the terminal holder is press-fitted into the through hole of the motor casing and fixed. Since the terminal is fixed to the motor casing via the terminal holder, it is not necessary to use a screw to fix the terminal to the motor casing, which improves assembly and simplifies the through fixing part of the terminal. Can be planned.

BRIEF DESCRIPTION OF THE DRAWINGS It is a block diagram of the electric motor of one Embodiment of this invention, (a) is sectional side view, (b) is Ib-Ib arrow sectional drawing of (a). In addition, (a) is sectional drawing equivalent to Ia-Ia arrow of (b). (A) is the figure which removes a brush etc. and shows the same part as FIG.1 (b), (b) is the perspective view which looked at the same part as (a) from the motor center axis direction. FIGS. 2A and 2B are views showing the relationship between the terminal, the slit of the brush holder, and the pigtail, wherein FIG. 2A is a cross-sectional view seen from above the pigtail, and FIG. 2B is the IIIb arrow of FIG. FIG.

(Electric motor)
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
The electric motor of this embodiment is used as a starter motor for an engine of a two-wheeled vehicle. When used, the rotating shaft is connected to the crankshaft of the engine.

  As shown in FIGS. 1 (a) and 1 (b), the electric motor M is provided in a motor casing 1 constituting a stator, a rotor 2 rotatably supported by the motor casing 1, and the rotor 2. A commutator 35 that switches the direction of the current flowing through the coil 33 of the rotor 2, a brush 60 that slides in contact with the segment 36 of the commutator 35 and flows current to the commutator 35, a terminal 71 that feeds the brush 60 from the outside, It has.

  The motor casing 1 is divided into a front casing 10 having a front end wall 11 and a peripheral wall 12, and a rear casing 20 having a rear end wall 21 and a peripheral wall 22. Then, the rear end 14 of the peripheral wall 12 of the front casing 10 and the front end 24 of the peripheral wall 22 of the rear casing 20 are fitted through a sealing material, and in this state, the connection is made to penetrate the rear end wall 21 of the rear casing 20. The bolt 25 is integrally formed by fastening the tip of the bolt 25 to the boss 15 of the front end wall 11 of the front casing 10. A permanent magnet 28 for field is fixed to the inner periphery of the peripheral wall 22 of the rear casing 20, thereby forming a stator.

  A circular center hole 13 is formed through the front end wall 11 of the front casing 10, and a circular recess 23 is formed at the center of the inner surface of the rear end wall 21 of the rear casing 20. The rotary shaft 31 of the rotor 2 is rotatably supported on the front end side (left side in FIG. 1A) in the center hole 13 of the front end wall 11 of the front casing 10 via a bearing 41, and the rear end (FIG. 1A ) Is supported by a recess 23 in the rear end wall 21 of the rear casing 20 via a bearing 43 so as to be rotatable. And the front end of the rotating shaft 31 protrudes outside through the sealing material 42 from the center hole 13 of the front casing 10.

  On the other hand, the rotor 2 includes a rotating shaft 31, a rotor core 32 provided integrally with the rotating shaft 31, and a coil 33 wound around a slot of the rotor core 32. A commutator 35 is disposed on the front end side of the rotor 2 located inside the motor casing 1. The commutator 35 has a plurality of segments 36 arranged in the circumferential direction, and the respective coils 33 are connected to the segments 36.

(Brush holder)
A resin brush holder 50 that holds the brush 60 is fixed inside the front casing 10 so as to surround the commutator 35.
As shown in FIGS. 2A and 2B, the brush holder 50 includes a bottom wall 51 disposed along the inner surface of the front end wall 11 of the front casing 10 and the peripheral wall 12 of the front casing 10. The bottom wall 51 is fixed to the front casing 10 by fastening the bottom wall 51 with screws 17 as shown in FIG.

  The bottom wall 51 is configured as an annular body having a circular hole 53 at the center, and a rectangular slit 56 formed in the peripheral wall 52 is formed at one place in the circumferential direction of the bottom wall 51 so as to be continuous with the circular hole 53. A notch 55 that communicates is provided. The slit 56 is a portion through which the terminal 71 is inserted, and the tip end portion 71 a of the terminal 71 is inserted through the slit 56.

The terminal 71 is inserted into the brush holder 50 from the outside of the front casing 10 through the through hole 18 of the peripheral wall 12 of the front casing 10 and the slit 56 of the peripheral wall 52 of the brush holder 50. The terminal 71 is fixed to the front casing 10 via a terminal holder 72 disposed on the outer periphery of the terminal 71.
The terminal holder 72 is made of resin, and corresponds to the through hole 18 of the front casing 10. The terminal main body 72 is formed in a substantially cylindrical shape, and the axially outer end of the main holder 72 a. The flange portion 72b is integrally formed.

  Here, the terminal 71 and the terminal holder 72 that holds the terminal 71 in a penetrating state are formed as an integral part terminal unit 70 by insert molding. The terminal 71 is fixed to the front casing 10 via the terminal holder 72 by press-fitting and fixing the holder main body 72 a of the terminal holder 72 into the through hole 18 of the front casing 10.

Further, as shown in FIG. 1B, a brush accommodating portion 57 </ b> A that holds a brush 60 </ b> A (60) for feeding (+ pole side) is provided near the slit 56 of the brush holder 50. On the other hand, at a position facing the brush housing portion 57A that holds the power supply brush 60A across the circular hole 53, there is a brush housing portion 57B that holds the grounding (negative pole) brush 60B (60). Is provided.
The brush accommodating portions 57A and 57B accommodate a power supply brush 60A and a grounding brush 60B, respectively. Each brush 60 </ b> A, 60 </ b> B is urged toward the center of the circular hole 53 by a spring 61. Thus, the brushes 60A and 60B are in sliding contact with the commutator 35 disposed on the rotor 2 with elasticity.

  One end of the pigtail 63 is joined to the grounding brush 60B, and the other end of the pigtail 63 is connected to the front casing 10 via the screw 17, so that the grounding brush 60B is grounded to the motor casing 1. Has been. One end of the pigtail 63 is joined to the power supply brush 60A, and the other end of the pigtail 63 is joined to the tip 71a of the terminal 71 inserted into the brush holder 50 through the slit 56 by spot welding. Has been.

  In this case, as shown in FIGS. 2 to 3, the other end of the pigtail 63 connected to the power supply brush 60 </ b> A is the side surface of the tip 71 a having a rectangular cross section of the terminal 71 (in the insertion direction of the terminal 71 with respect to the slit 56. The surface is aligned with a direction perpendicular to the insertion direction of the terminal 71 (a direction perpendicular to the bottom wall 51 of the brush holder 50), and is joined by spot welding in a state in which the outer peripheral surface is in contact therewith. .

Here, the width of the slit 56 of the brush holder 50 is set as follows. That is, of the gap S between the peripheral edge of the slit 56 of the brush holder 50 and the terminal 71, the gap S 1 at a position corresponding to the joint portion between the pigtail 63 and the terminal 71 is set smaller than the wire diameter D of the pigtail 63. ing.
That means
D> S1
Is set to

Moreover, in maintaining the relationship, the relationship between the width H of the slit 56, the width B of the terminal 71, and the wire diameter D of the pigtail 63 is
B + D>H> B
Is set to

  Further, the length of the pigtail 63 from the brush 60 </ b> A to the terminal 71 is set smaller than the length from the brush 60 </ b> A to the through hole 18 of the front casing 10 via the slit 56 of the brush holder 50.

(Terminal and brush assembly procedure)
The terminal 71 and the brush 60A are assembled according to the following procedure.
First, the terminal unit 70 including the terminal 71 and the terminal holder 72 is manufactured by insert molding. Next, the brush 60 </ b> A, the pigtail 63, and the terminal 71 are joined outside the motor casing 1.

  Next, the brush 60 </ b> A, the pigtail 63, and the tip 71 a of the terminal 71 are inserted from the through hole 18 of the motor casing 1 (front casing 10), and the terminal unit 70 is fixed to the motor casing 1. At the same time, while taking in the brush 60A, the pigtail 63 and the like inside by using the notch 55 of the brush holder 50, the terminal 71 is connected to the slit 56 of the brush holder 50 from one end in the axial direction (the lower end in FIG. 2B). The brush holder 50 is accommodated in the front casing 10 and fixed by inserting the tip portion 71a. Thus, the attachment of the terminal 71 and the assembly of the brush holder 50 can be completed.

(effect)
According to the electric motor M configured as described above, the following effects can be obtained.
First, since the gap between the peripheral edge of the slit 56 of the brush holder 50 and the terminal 71 is set smaller than the wire diameter of the pigtail 63 joined to the terminal 71, an external force acts to cause the terminal 71 to move to the motor. Even when trying to come out from the casing 1, the pigtail 63 hits the wall surface (circumferential wall 52) of the brush holder 50 around the slit 56 and stops, so that the terminal 71 can be prevented from coming off.

  Accordingly, it is possible to increase the reliability of fail-safe against the disconnection of the terminal 71, thereby greatly reducing the possibility that the brush 60 </ b> A and the pigtail 63 are exposed to the outside due to some trouble. In addition, since the portion for guaranteeing the removal of the terminal 71 is provided inside the motor casing 1, it is not necessary to provide a strong terminal fixing structure such as screwing outside the motor casing 1. Simplification of the external structure can be achieved. Thereby, it can contribute to the reduction of the occupation space when mounting the electric motor M in a vehicle. Further, since the brush holder 50 is provided with a function of preventing the terminal 71 from coming off, the number of peripheral parts around the terminal 71 can be reduced, which can contribute to cost reduction.

  Further, by providing a specific restriction on the length of the pigtail 63, the terminal 71 can be prevented from coming off from the motor casing 1 more reliably. Therefore, the reliability of fail safe can be further increased.

  In addition, since the pigtail 63 is joined to the terminal 71 by spot welding, the resistance at the time of preventing the terminal 71 from being pulled out can be increased by the pigtail 63 hitting the wall surface (circumferential wall 52) of the brush holder 50. The reliability of joining the pigtail 63 and the terminal 71 can be improved.

  Further, the terminal 71 and the resin terminal holder 72 are formed as an integral part terminal unit 70 by insert molding, and the terminal holder 72 is press-fitted into the through hole 18 of the motor casing 1 and fixed. Is fixed to the motor casing 1 via a terminal holder 72. For this reason, it is not necessary to use a screw or the like for fixing the terminal 71 to the motor casing 1, so that the assemblability is improved and the through-fixing portion of the terminal 71 can be simplified.

M electric motor 1 motor casing 12 peripheral wall 2 rotor 18 through hole 33 coil 35 commutator 50 brush holder 52 peripheral wall 56 slit 60, 60A, 60B brush 63 pigtail 70 terminal unit 71 terminal 72 terminal holder

Claims (3)

A motor casing constituting the stator;
A rotor rotatably supported by the motor casing;
A commutator provided in the rotor and switching a direction of a current supplied to a coil of the rotor;
A brush that slides in contact with the commutator and passes a current through the commutator;
A terminal inserted into the brush holder from the outside of the motor casing through a through-hole in the peripheral wall of the motor casing;
A pigtail joined to the terminal and the brush and electrically connecting the terminal and the brush;
A resin-made brush holder fixed inside the motor casing,
On the peripheral wall of the brush holder, a slit that can receive the terminal from one end side in the axial direction is formed at a position corresponding to the terminal,
Of the gap between the peripheral edge of the slit of the brush holder and the terminal, the gap corresponding to the joint between the pigtail and the terminal is set smaller than the wire diameter of the pigtail. Electric motor.   The length of the pigtail from the brush to the terminal is set shorter than the length from the brush to the through hole of the motor casing via the slit of the brush holder. Item 4. The electric motor according to Item 1.   The terminal and a resin-made terminal holder that holds the terminal in a penetrating state are formed as an integral terminal unit by insert molding, and the terminal holder of the terminal unit is press-fitted into the through hole of the motor casing. The electric motor according to claim 1, wherein the terminal is fixed to the motor casing via a terminal holder by being fixed.

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