JPH09308203A - Dc motor with brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC motor with a brush having no fear of disconnection of a lead terminal of a noise absorbing capacitor due to vibration. SOLUTION: Noise absorbing capacitors 31, 32 are respectively mounted on printed boards 29, 30. The boards 29, 30 are clamped at a brush retaining plate 14 for retaining the brushes 15, 16 of a motor with brushes with screws 42. The one ends of the capacitors 31, 32 are connected to the brushes 15, 16 via brush side leads 33, 34 fixed to the boards 29, 30, and the other ends of the capacitors 31, 32 are connected to the housing of the motor via earth side leads 35, 36 fixed to the boards 29, 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor with a brush, and more particularly to a DC motor with a brush equipped with a noise absorbing capacitor for suppressing generation of noise caused by rectified sparks.

[0002]

2. Description of the Related Art In a DC motor with a brush, which is rectified by a commutator attached to an end of a rotary shaft of a rotor and connected to an armature coil, and a brush brought into contact with the commutator, a commutation spark is used. This may cause noise (hereinafter referred to as brush noise), which may cause wireless interference to nearby devices. For example, if a brushed DC motor is used to drive a wirelessly guided golf cart, brush noise can cause erroneous guidance in the golf cart.

Therefore, when a DC motor with a brush is used, in order to suppress the occurrence of brush noise, noise is generated between each of the pair of brushes of the motor and the rear cover of the motor to which the brush holding plate is attached. The absorption capacitor is electrically connected.

FIG. 8 and FIG. 9 show a mounting structure of a noise absorbing capacitor in a conventional DC motor with a brush. FIG. 8 is a front view of a brush holding plate to which a noise absorbing capacitor is mounted, and FIG. It is explanatory drawing which showed the connection method of the absorption capacitor in more detail.

8 and 9, 31 'and 32'
Are respectively the first and second noise absorbing capacitors,
The tip portions of the one lead terminals 31a 'and 32a' drawn from the capacitors 31 'and 32', respectively, are the first and second lead terminals 31a 'and 32a' drawn from the first and second brushes 15 'and 16', respectively. The ends of the pigtails 15a 'and 16a' are connected to the respective ends of the external lead wires 24 'and 25' by crimp connection fittings 51 and 52. The tips of the other lead terminals 31b 'and 32b' drawn from the first and second noise absorbing capacitors 31 'and 32' are commonly connected to a grounding terminal fitting 39 'having a crimping terminal portion. There is.

First and second brushes 15 'and 16'
Are respectively held by the first and second brush holders 17 'and 18' attached to the brush holding plate 14 ', and the external lead wires 24' and 25 'are led to the outside through the grommet 26'. There is. The grounding terminal fitting 39 'is fastened together with the brush holding plate 14' by a screw (not shown) and electrically connected to a rear cover (not shown) of the electric motor. A brush holding plate 14 ',
The parts attached to the plate form a brush holding plate assembly.

[0007]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In a conventional DC motor with a brush to which a noise absorbing capacitor is attached,
First and second noise absorbing capacitors 31 'and 32
'One of the lead terminals 31a' and 32a '
Of the lead-out wires 24 'and 25' and the brush pictule 15a 'of the brush by the crimp connection fittings 51 and 52.
And 16a 'by crimp connection, and the other lead terminal 31
Since the tips of b'and 32b 'were commonly connected to the grounding terminal fitting 39', each capacitor was attached to the brush holding plate in a floating state without being fixed to the plate.

Therefore, the first and second noise absorbing capacitors are in a state of being easily moved by vibration, and when each capacitor moves, it is close to the crimp connection fitting and the grounding terminal fitting of the lead terminal pulled out from each capacitor. There was a risk of disconnection due to fatigue due to vibration. In order to prevent the movement of each capacitor, it is possible to prevent the disconnection by applying an adhesive around the crimp connection fitting and the ground terminal fitting and adhering these parts to the brush plate. Since a lot of man-hours are required for the bonding work, the cost is inevitably high.

Further, in the conventional DC motor with brush equipped with the noise absorbing capacitor, the capacitor could not be freely attached and detached. Therefore, the portion of the brush holding plate assembly excluding the noise absorbing capacitor was
There is also a problem that it cannot be shared by an electric motor that requires noise countermeasures and an electric motor that does not require noise countermeasures.

An object of the present invention is to provide a DC motor with a brush that eliminates the possibility that the lead terminals of the noise absorbing capacitor will be disconnected due to vibration.

Another object of the present invention is to provide a noise absorbing capacitor in an assembly composed of a brush holding plate and parts assembled to the plate so that the noise absorbing capacitor can be easily attached and detached. It is an object of the present invention to provide a DC motor with a brush in which the parts other than the above can be shared both when noise countermeasures are required and when noise countermeasures are not required, and the commonality of parts is improved.

[0012]

According to the present invention, there is provided a housing having a case main body having both ends opened, a front cover and a rear cover detachably attached to one end and the other end of the case main body, and the case main body. A stator fixed to the inside, a rotary shaft supported by bearings respectively attached to the front cover and the rear cover, and one end of which is led to the outside from the front cover side, and an armature core attached to the rotary shaft. A rotor formed by winding an armature coil, a commutator attached to the end of the rotary shaft on the rear cover side and connected to the armature coil, a brush holding plate attached to the rear cover, and a brush holding plate The present invention relates to a DC motor with a brush including first and second brushes that are brought into contact with the commutator.

In the present invention, the first and second printed circuit boards are fixed to the brush holding plate, and the first and second printed circuit boards are fixed.
The first and second noise absorbing capacitors are attached to the respective printed circuit boards. One ends of the first and second noise absorbing capacitors are electrically connected to the first and second brushes through the first and second brush side lead wires having one ends fixed to the first and second printed circuit boards, respectively. Connect, first
The other ends of the second and second noise absorbing capacitors are electrically connected to the housing through first and second ground side lead wires, one ends of which are fixed to the first and second printed circuit boards, respectively.

In many brush DC motors, the brush holding plate is attached to the rear cover with screws. Further, the brush holding plate is attached with first and second terminal fittings provided with terminal screws used for connecting lead wires led out to the outside, and these first and second terminal fittings are respectively attached to the first and second terminal fittings. And often connected to a second brush.

In the case of such a brush DC motor, one end of each of the first and second noise absorbing capacitors is
It is connected to one end of the first and second brush side lead wires via wiring patterns respectively provided on the first and second printed circuit boards, and the other ends of the first and second noise absorbing capacitors are connected to the first and second And other wiring patterns provided on the second printed board, respectively, and are connected to one ends of the first and second ground side lead wires. First and second brush-side terminal plates are respectively connected to the other ends of the first and second brush-side lead wires, and the first and second brush-side terminal plates are respectively the first and second terminals. Through the terminal screw provided on the metal fitting, the first
And the second terminal fitting. First and second ground side terminal plates are connected to the other ends of the first and second ground side lead wires, respectively, and the first and second ground side terminal plates respectively use the brush holding plate as a rear cover. Tighten the fixing screws together with the brush holding plate to electrically connect to the rear cover.

With the above arrangement, the first and second noise absorbing capacitors are electrically connected between the first and second brushes and the rear cover, respectively, so that the generation of brush noise is suppressed. be able to.

Further, as described above, the first and second printed circuit boards fixed to the brush holding plate are provided with the first and second printed circuit boards.
With the structure to attach the noise absorption capacitor of
It is possible to eliminate the risk that the first and second noise absorbing capacitors move due to vibration and their lead terminals are disconnected due to fatigue.

Further, as described above, the first and second brush side lead wires are connected to the first and second terminal fittings through the terminal screws provided on the first and second brush side terminal plates, respectively. Then, the first and second ground side terminal plates are respectively tightened together with the brush holding plate by the screws that fix the brush holding plate to the rear cover and connected to the rear cover. The first and second printed circuit boards with the lead wire and the ground side lead wire attached thereto can be easily attached and detached. Therefore, parts other than the first and second printed circuit boards can be shared when noise countermeasures are required and when noise countermeasures are not required, and mass productivity can be improved.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of the configuration of a DC motor with a brush according to the present invention. The upper half of the same figure shows a vertical cross section of the electric motor, and the lower half is the side surface of the electric motor. Is shown in partial cross section.

In FIG. 1, reference numeral 1 denotes a case main body made of a cylindrical steel pipe having both ends opened, and a front cover 2 and a rear cover 3 are detachably fitted to one end and the other end of the case main body, respectively. The front cover 2 and the rear cover 3 are fastened to each other by through bolts 4 to form a motor housing.

In the illustrated example, a stator 5 made of a cylindrical permanent magnet is fixed to the inner circumference of the case body 1. Reference numeral 6 denotes a rotary shaft supported by bearings 7 and 8 attached to the front cover 2 and the rear cover 3, respectively, and one end of the rotary shaft is led out from the front cover 2 side to the outside. An armature core 9 is press-fitted and fixed to the rotating shaft 6, and an armature coil 10 is wound around the armature core to form a rotor 11. A commutator 12 connected to the armature coil 9 is attached to an end of the rotating shaft 9 on the rear cover 3 side.

A brush holding plate assembly 13 includes a brush holding plate 14 attached to the rear cover 3 and a first brush 15 held by the brush holding plate 14 and brought into contact with the commutator 12. And a second brush (not shown). First and second noise absorbing capacitors (not shown in FIG. 1) are also attached to the brush holding plate assembly 13 as described later.

FIG. 2 shows details of the brush holding plate assembly 13 used in the DC motor with brush shown in FIG. In FIG. 2, the brush holding plate 14 is formed in the shape of an annular disc made of an insulating material such as plastic, and one surface of the brush holding plate 14 is placed in a symmetrical position in the radial direction and is made of a metal plate. First and second brush holders 17 and 1 of the same shape
8 is riveted. The first and second brushes 15 and 16 are slidably inserted into the brush insertion grooves formed in the first and second brush holders 17 and 18, respectively, and the tips of both brushes are opposed to each other. There is. The first and second brushes 15 and 16 are connected to the brush holding plate 1 by the first and second spiral springs 19 and 20, respectively.
4 is suppressed in the central part side. The first and second brush holders 17 and 18 also have terminal screws 21 respectively.
The first and second terminal fittings 22 and 23 having the above are integrally formed. First and second terminal fittings 22 and 23
One end of each of the external lead wires 24 and 25,
Pigtails 15 a and 16 a respectively led out from the rear end portions of the first and second brushes 15 and 16 are connected via terminal screws 21. The external lead wires 24 and 25 are led to the outside through a grommet 26. The brush holding plate 14 is provided with mounting holes 14 a and 14 b for mounting the brush holding plate on the rear cover 3.

First and second printed circuit board assemblies 27 and 28, which are identically formed, are attached to one surface of the brush holding plate 14. FIG. 3 shows the configuration of the first and second printed circuit board assemblies 27 and 28. In FIG. 3, the reference numerals without parentheses indicate the reference numerals of the respective parts of the first printed circuit board assembly 27, The reference numerals attached with indicate the reference numerals of the respective parts of the second printed circuit board assembly 28. As shown in FIG. 3, the first printed circuit board assembly 27 has wiring patterns 29a and 2 on the back surface.
First printed circuit board 29 having 9b and lead terminals 31a on one end side of wiring patterns 29a and 29b, respectively.
And a first noise absorbing capacitor 31 attached to the first printed board 29 by soldering the lead terminals 31b on the other end side, and a first brush side lead wire 33 having one end soldered to the wiring pattern 29a. , Wiring pattern 2 at one end
The first ground side lead wire 35 soldered to 9b, the first brush side terminal plate 37 connected to the other end of the first brush side lead wire 33, and the first ground side lead wire 35 It is composed of a first ground side terminal plate 39 connected to the end. The first printed circuit board 29 is provided with printed circuit board mounting holes 29c and 29d.

The second printed circuit board assembly 28 includes a second printed circuit board 3 having wiring patterns 30a and 30b.
0, the second noise absorbing capacitor 32 mounted on the second printed circuit board 30 by soldering the lead terminal 32a on one end side and the lead terminal 32b on the other end side to the wiring patterns 30a and 30b, respectively. Wiring pattern 3
0a, the second brush-side lead wire 34, one end of which is soldered to the wiring pattern 30b, the second ground-side lead wire 36, and the other end of the second brush-side lead wire 34, which is connected to the other end. The second brush side terminal plate 38 and the second ground side terminal plate 40 connected to the other end of the second ground side lead wire 36 are configured in exactly the same manner as the first printed circuit board assembly 27, The second printed circuit board 30 is provided with printed circuit board mounting holes 30c and 30d.

The first printed circuit board assembly 2 shown in FIG.
As shown in FIGS. 2 and 4 (A-A cross-sectional view of FIG. 2), 7 is arranged in a state in which the first printed board 29 is brought into contact with the brush holding plate 14 via the spacer collar 41. Attached to the brush holding plate 14 by a screw 42 penetrating through the printed board mounting holes 29c and 29d, the spacer collar 41, and a hole provided in the brush holding plate 14, and a nut 43 screwed into the screw 42. ing. The second printed circuit board assembly 28 is attached to the brush holding plate in exactly the same manner.

Further, as can be seen in FIGS. 5A to 5C in which the T portion (terminal portion) of FIG. 2 is enlarged, the first and second printed circuit board assemblies 27 and 28, respectively. The first and second brush side terminal plates 37 and 38 connected to the brush side lead wires 33 and 34 of the
It is connected to the first and second terminal fittings 22 and 23 via. The first and second ground side terminal plates 39 and 40 connected to the ground side lead wires 35 and 36, respectively, are screws (not shown) inserted through the mounting holes 14a and 14b for mounting the brush holding plate 14 on the rear cover. Thus, it is fastened together with the brush holding plate 14 and electrically connected to the rear cover 3.

FIG. 6 shows an electric circuit in a state where the brush holding plate assembly 13 of FIG. 2 to which the first and second printed circuit board assemblies 27 and 28 are attached is assembled to the electric motor. In this state, the series circuit of the first and second noise absorbing capacitors 31 and 32 is provided at both ends of the series circuit of the first and second brushes 15 and 16, the commutator 12, and the armature coil of the rotor 11. The capacitors 31 and 32 absorb the brush noise generated by the generation of the rectified sparks, which are connected in parallel.

First and second noise absorbing capacitors 3
1 and 32 are the first and second printed circuit boards 29, respectively.
, And the printed circuit boards 29 and 30 are fixed to the brush holding plate by being screwed to the brush holding plate 14, so that even if vibration is applied, the first and second noise absorbing The lead terminals 31a, 31b and 32a, 32b of the capacitor do not vibrate significantly, and there is no risk of disconnection of the lead terminals.

The first and second printed circuit board assemblies 27 and 28 are respectively attached to the printed circuit board mounting screws 4.
2, the terminal screw 21 and the brush holding plate attaching screw are detachably attached to the brush holding plate assembly 13. Therefore, in the case of a brushed DC motor that does not require a noise absorbing circuit, it is shown in FIG. As described above, the brush holding plate assembly with the first and second printed circuit board assemblies 27 and 28 removed can be used as it is.

[0031]

As described above, according to the present invention, the noise absorbing capacitor is attached to the printed circuit board, and the printed circuit board is fixed to the brush holding plate. There is an advantage that disconnection due to vibration can be prevented.

Since the printed circuit board to which the noise absorbing capacitor is attached is detachably attached to the brush holding plate with a screw, a printed circuit board assembly of an assembly consisting of the brush holding plate and the parts assembled to the plate. The part except for can be shared with and without the noise absorption circuit,
Costs can be reduced by increasing the commonality of parts.

[Brief description of drawings]

FIG. 1 is a structural diagram showing an overall structure of a brush DC motor according to the present invention.

FIG. 2 is a front view showing a brush holding plate assembly used in the electric motor of FIG.

3 is a front view of a printed circuit board assembly used in the brush holding plate assembly of FIG. 2. FIG.

FIG. 4 is a sectional view taken along line AA of FIG. 2;

FIG. 5 is an enlarged view of the terminal portion T of FIG.
(A) is a top view, (b) is a front view, and (c) is a side view.

FIG. 6 is an electric circuit diagram showing a noise absorption circuit of the electric motor.

7 is a front view showing a state where the printed circuit board assembly is removed from the brush holding plate assembly shown in FIG.

FIG. 8 is a front view showing an example of a brush holding plate assembly used in a conventional DC motor with a brush.

9 is an explanatory diagram showing a connection structure of a noise absorbing capacitor in the brush holding plate assembly shown in FIG.

[Explanation of symbols]

 1 Case Main Body 2 Front Cover 3 Rear Cover 5 Stator 6 Rotating Shaft 7, 8 Bearing 9 Armature Iron Core 10 Armature Coil 11 Rotor 12 Commutator 13 Brush Holding Plate Assembly 14 Brush Holding Plate 15 First Brush 16 Second Brush 21 Terminal screw 22 First terminal metal fitting 23 Second terminal metal fitting 24, 25 External lead wire 27 First printed circuit board assembly 28 Second printed circuit board assembly 29 First printed circuit board 29a, 29b Wiring pattern 30 2nd printed circuit boards 30a, 30b Wiring pattern 31 1st noise absorption capacitor 32 2nd noise absorption capacitor 33 1st brush side lead wire 34 2nd brush side lead wire 35 1st earth side lead Wire 36 Second ground side lead wire 37 First brush side terminal plate 38 Second Brush-side terminal plate 39 first ground-side terminal plate 40 and the second ground-side terminal plate

Claims (2)

[Claims] 1. A housing having a case main body having both ends opened, a front cover and a rear cover detachably attached to one end and the other end of the case main body, and a stator fixed to the inside of the case main body. A rotary shaft supported by bearings respectively attached to the front cover and the rear cover and having one end led out to the outside from the front cover side; and an armature coil wound around an armature core attached to the rotary shaft. A rotor, a commutator attached to the rear cover side end of the rotating shaft and connected to the armature coil, a brush holding plate attached to the rear cover, and a brush holding plate held by the brush holding plate. A DC motor with a brush, comprising: a first brush and a second brush that are brought into contact with a commutator; The first and second printed circuit boards are fixed to the holding plate, the first and second noise absorbing capacitors are attached to the first and second printed circuit boards, respectively, and the first and second noise absorbing circuits are provided. One end of the capacitor for use is passed through the first and second brush side lead wires, one end of which is fixed to the first and second printed circuit boards, respectively.
And second brushes, and the other ends of the first and second noise absorbing capacitors are first and second grounds whose one ends are fixed to the first and second printed circuit boards, respectively. A DC motor with a brush, which is electrically connected to the housing through a side lead wire. 2. A housing having a case body supporting a stator on an inner circumference thereof, a front cover and a rear cover detachably attached to one end and the other end of the case body, and the front cover and the rear cover, respectively. A rotating shaft supported by a mounted bearing and having one end led out from the front cover side to the outside, a rotor having an armature coil wound around an armature core attached to the rotating shaft, and the rotating shaft of the rotating shaft. A commutator attached to the end on the rear cover side and connected to the armature coil,
A brush holding plate attached to the rear cover with screws, and first and second brushes held by the brush holding plate and brought into contact with the commutator are provided to the brush holding plate. Brushes to which first and second terminal fittings having terminal screws for connecting lead wires are attached, and the first and second terminal fittings are connected to the first and second brushes, respectively. A direct current electric motor, the first and second printed circuit boards fixed to the brush holding plate, the first and second noise absorbing capacitors respectively mounted on the first and second printed circuit boards, One end of each of the first and second noise absorbing capacitors is connected via a wiring pattern provided on each of the first and second printed circuit boards. Other than the first and second noise absorbing capacitors via the first and second brush side lead wires connected to each other and the other wiring patterns provided on the first and second printed circuit boards First and second ground-side lead wires having one ends connected to the ends, and first and second brush-side terminal plates connected to the other ends of the first and second brush-side lead wires, respectively. And a first and a second ground-side terminal plate connected to the other ends of the first and the second ground-side lead wires, respectively, wherein the first and the second brush-side terminal plates are respectively the aforesaid. First
And second terminal fittings connected to the first and second terminal fittings through terminal screws provided on the second terminal fittings, and the first and second ground side terminal plates respectively fix the brush holding plate to the rear cover. A DC motor with a brush, which is fastened together with a brush holding plate by a screw to be electrically connected to the rear cover.