JPH07135752A - Dc motor - Google Patents

Abstract

PURPOSE:To make the soldering work of circuit components of which the noise- proof circuit of a DC motor is composed easy and avoid the defective contact of brushes, the short-circuit and breakage of a capacitor, etc., which are caused by the soldering work. CONSTITUTION:A pair of brushes are provided on the inner side of a brush base 32 which is attached to a housing 21 so as to close the opening of the housing 21 and a pair of the brush terminal parts 46b protrude from the outer surface of the brush base 32 and two receptacle parts 36 and 37 which are recessed inward are formed on the brushed base 32. A circuit board 50 has terminal holes 52 and 53 and brush terminal connection lands 54 and 55 which are patterned around the terminal holes 52 and 53. The brush terminals are inserted into the terminal holes 52 and 53 and soldered to the brush terminal connection lands 54 and 55 and the circuit board 50 is tightly attached to the outer side of the brush base 32. Circuit components of which a noise-proof circuit is composed are attached to the inner side of the circuit board 50 between the brush terminal connection lands 54 and 55 and power supply connection parts 56 and 57 so as to be housed in the respective receptacle parts 36 and 37.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a DC motor.

[0002]

2. Description of the Related Art A DC motor is often used as a drive source for various devices. Generally, a DC motor supplies a DC power source to a commutator of a rotor having a plurality of coils through a pair of brushes, and operates by a current flowing through the coils or a magnetic field generated by the current and a magnetic field generated by a permanent magnet or the like. The rotor is rotated, and the power supply to the plurality of coils is switched every time the rotor rotates by a predetermined angle, so that the rotor continues to rotate.

However, in the DC motor which switches the energization to each coil via the brush as described above, when the energization to the coil is switched, a pulsed noise signal induced by the inductance of the coil flows out to the power supply line side. Then, it adversely affects other circuits driven by this power supply.

Therefore, a DC motor has conventionally been provided with a noise prevention circuit formed of a choke coil and a capacitor.

FIG. 11 shows a conventional DC motor 1 equipped with a noise prevention circuit for preventing noise from flowing out to the power supply line.
0 is shown.

The DC motor 10 has a cylindrical housing 11 having an opening at one end surface, a rotor 12 supported in the housing 11, and a brush base 13 fixed so as to close the opening surface of the housing 11. As shown in FIG. 12, a pair of brush support plates 14 and 15 are fixed to the inner surface side of the brush base 13.

Each of the brush supporting plates 14 and 15 has a brush base 1
14a, 15a fixed to the inner surface 13a of No. 3 by welding.
And leaf springs 14b and 15b rising from the respective bases and extending to the center of the brush base. Brushes 16 and 17 are fixed to the tips of the leaf springs so as to face each other. Each of the brushes 16 and 17 is in external contact with the commutator 12a of the rotor 12 by the biasing force of the leaf spring portion.

The brush base 13 has a pair of power supply terminals 18,
19, one end side 18a, 19a of the brush base inner surface 13
It is attached so that it projects toward the a side and the other ends 18b and 19b project toward the brush base outer surface 13b.

Choke coils L are soldered between the base portion 14a of the brush support plate 14 and one end 18a of the power supply terminal 18 and between the base portion 15a of the brush support plate 15 and one end 19a of the power supply terminal 19, respectively. Capacitors C are soldered between the power supply terminals protruding to the outer surface of the brush base 13 and between the power supply terminals and the housing 11.

Therefore, a low-pass filter type noise prevention circuit composed of the choke coil L and the capacitor C is formed between each power supply terminal and the brush supporting plate, and the pulse-like noise generated on the brush side is directed to the power supply terminal side. Outflow is suppressed by this noise prevention circuit.

[0011]

However, such a conventional DC motor has the following problems. (1) It takes time and effort to solder both ends of the choke coil between the brush support plate and the power supply terminal on the inner surface side of the brush base, and moreover the paste scattered during soldering adheres to the brush and makes contact. Cause defects.

(2) If the choke coil is poorly soldered, the brush base must be removed from the housing.

(3) The legs of the capacitor to be soldered to the outer surface of the housing come into contact with each other to cause a short circuit or the capacitor is damaged by an external force.

(4) In order to attach a relatively long component such as a choke coil to the inner surface of the brush base, the distance between the brush support plate and the corresponding power supply terminal becomes long, and the motor is viewed from the outside. At times, the positional relationship between the internal brush and the power supply terminal corresponding to the brush cannot be intuitively determined, and the polarity is likely to be incorrect when the power cord or the like is connected.

The present invention solves such a problem and facilitates the soldering work of the circuit components forming the noise prevention circuit,
It is an object of the present invention to provide a DC motor in which contact failure of a brush due to soldering and short-circuit or damage of a capacitor do not occur.

[0016]

In order to achieve the above-mentioned object, a DC motor of the present invention has a housing and a brush base fixed so as to close an opening surface of the housing, so that a rotor in the housing is fixed. In a DC motor that rotates the rotor by a DC power supply that is rotatably supported and is supplied to a pair of brushes fixed to the inner surface of the brush base through a noise prevention circuit, the inner surface side of the brush base is A pair of brush terminals respectively connected to the pair of brushes and protruding to the outer surface of the brush base, a pair of power supply connection portions for supplying power to one surface side, and a pair of brush terminals connectable to the pair of brush terminals And a circuit part forming the noise prevention circuit between the power source connection part and the brush terminal connection part is attached to the other surface side, and the other surface side is connected to the other surface side. A circuit board fixed to the outer surface of the brush base by connecting the pair of brush terminal connecting parts to the pair of brush terminals in a state of being superposed on the outer surface of the brush base, and an inner surface direction from the outer surface of the brush base. And a receiving portion for receiving the circuit component mounted on the other surface side of the circuit board.

[0017]

As described above, in the DC motor of the present invention, the power supply connection portion and the brush terminal connection portion are formed on one surface side, and the circuit board forming the noise prevention circuit is attached to the other surface side of the circuit board. With the circuit parts stacked on the outer surface of the brush base so that they fit into the receiving part of the brush base,
Since the structure is fixed to the outer surface of the brush base, it can be assembled without the need to solder the parts on the inner surface side of the brush base or directly attach the capacitor outside the brush base.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1 to 6 show a DC motor 20 of one embodiment. In these figures, this DC motor 2
The housing 21 of 0 has one end surface 21a opened and the other end surface 2
1b is formed in a closed hollow cylindrical shape.

Two permanent magnets 23 and 24 having different magnetic poles are fixed to the inner peripheral wall 21c of the housing 21 so as to face each other. A bearing 25 is fixed to the center of one end surface of the housing 21.

A rotor 26 is arranged at the center of the housing 21. The rotor 26 includes a shaft 27 having one end protruding from a shaft hole of the bearing 25 and a shaft 27.
Iron core 28 formed in the middle part of the three-pronged part at an angle of 120 degrees
a to 28c and coils 29a to 29 wound around the respective iron cores
c, and three commutator pieces 30a to 30c separated from each other at the position of 120 degrees on the outer circumference of the other end of the shaft 27 (see FIG. 7).
And a relay board 31 for relaying between each commutator piece and each coil, and each commutator piece 30a.
The winding start portion of one coil and the winding end portion of the adjacent coil are connected to ˜30c. A resistor material (not shown) having a high resistivity is applied to the surface of the relay substrate 31 to prevent sparks, and both ends of each coil are terminated with a high resistance value.

A circular brush base 32 is attached to the opening surface of the housing 21. Outer surface 3 of brush stand 32
2a is formed to have substantially the same diameter as the outer diameter of the housing 21, and the outer edge of the inner surface 32b of the brush base 32 has an outer diameter slightly smaller than the inner diameter of the housing 21.
A cylindrical portion 32c inserted inside is formed.

The brush base 32 is formed with a notch 33 which is cut from the outer edge to the side surface. The outer edge 22 of the housing 21 is bent inwardly in the notch 33, whereby the brush base 32 is bent. Are fixed to the housing 21.

At the center of the inner surface 32b of the brush base, there is formed a bearing support portion 34 which is recessed in a substantially circular shape toward the outer surface. At the center of the outer surface of the brush base is formed a columnar shape along the bearing support portion 34. A protruding portion 35 is provided. A circuit board 50, which will be described later, is provided on the right side of the protrusion 35.
In order to receive the circuit component, the receiving portion 36 is formed so as to be recessed inward, and a vertically long receiving portion 37 is formed on the left side of the projecting portion 35.

A spherical bearing 38 for supporting the other end side of the shaft 27 of the rotor 26 rotatably by inserting the other end side of the shaft 27 of the rotor 26 is supported by a pressing spring 39 on the bearing support portion 34 of the brush base. ing. Also, the bearing 38
A pair of brush support plates 40 and 41 formed of phosphor bronze are fixed at symmetrical positions with respect to each other.

The base 4 on one end side of the brush support plates 40, 41
0a and 41a are one ends 45a of the brush terminals 45 and 46,
It is fusion-bonded in a state of being sandwiched between the 46a side and the inner surface of the brush base. The leaf spring portion 40 of the brush support plates 40 and 41
b and 41b stand up from the respective bases at a substantially right angle and extend in the direction of the bearing 38, and the tips thereof are formed so as to face each other above the bearings. Brushes 42 and 43 are fixed to the tips of the leaf spring portions 40b and 41b of the brush support plates 40 and 41 so as to face each other. In the leaf spring portion of each brush support plate 40, 41,
A rubber material 44 for preventing resonance is attached. Brush 4
The two and 43 are in contact with the two commutator pieces of the rotor 26 from both sides by the urging force of the brush support plates 40 and 41.

The other ends 45b, 4 of the brush terminals 45, 46
6b is a central protruding portion 35 on the outer surface 32a of the brush base 32.
It sticks out and protrudes in a symmetrical position.

The circuit board 50 is formed in a circular shape having a diameter smaller than or substantially the same as the outer diameter of the brush base 32, and at the center thereof, slightly smaller than the outer diameter of the protrusion 35 at the center of the outer surface of the brush base 32. A large diameter circular hole 51 is provided. In addition, terminal holes 52 and 53 are formed above and below the circular hole 51 at positions corresponding to the brush terminals 45 and 46 of the brush base 32.

Terminal holes 52, 5 on one surface 50a side of the circuit board
3, brush terminal connecting portions 54 and 55 which are solderable between the brush terminals 45 and 46 which are inserted into the terminal holes 52 and 53 and project to the one surface side of the circuit board are formed. There is. In addition, a pair of power supply connecting portions 56 and 57 for soldering the power supply cords are formed on the sides of the brush terminal connecting portions 54 and 55, and the power supply connecting portion 5 is formed.
A ground connection portion 58 for ground connection to the housing 21 is pattern-formed in the middle of 6 and 57.

On the other hand, on the other surface 50b of the circuit board 50, choke coils L1 and L2 forming a noise prevention circuit for preventing noise from flowing out to the power supply line between the brush terminal connection portion and the power supply connection portion. And capacitors C1 to C3 are attached.

That is, as shown in FIG. 6, one terminal of each of the choke coils L1 and L2 is connected to one surface 50a of the circuit board 50.
On the right side of the circular hole 51, the other terminal is pattern-connected to both ends of the capacitor C1. Between the other terminal of the choke coil L1 and the power supply connection portion 56 and between the other terminal of the choke coil L2 and the power supply connection portion 57,
It is connected on one side of the circuit board. Further, one terminals of the capacitors C2 and C3 are connected to the respective power source connecting portions 56 and 57, and the other terminals of the capacitors C2 and C3 are connected to the ground connecting portion 58.

Here, the mounting positions of the respective circuit parts are as follows: the brush terminals 45 and 46 of the brush base 32 are inserted into the terminal holes 52 and 53.
With the other surface of the circuit board 50 and the outer surface of the brush base 32 overlapped with each other, and two choke coils L arranged in a V shape on the left side (in FIG. 6) of the circular hole 51.
1, L2 and the capacitor C1 are accommodated in the receiving part 36 on the right side of the brush base, and the two capacitors C2, C3 arranged vertically on the right side of the circular hole 51 (in FIG. 6) are accommodated in the receiving part 37 on the left side. Is set in advance.

Further, the pattern of the noise prevention circuit formed between each brush terminal connection portion and the power supply connection portion is formed so as to be line-symmetrical with respect to the circular hole 51.

In the circuit board 50 thus formed, the brush terminals 45 and 46 are inserted into the terminal holes 52 and 53, and the other surface side on which the circuit parts are attached is the brush base 32.
The brush base 32 is soldered between the brush terminals and the terminal connecting portions in a state of being superposed on the outer surface of the brush base 32.
It is firmly attached to the outer surface of the.

Therefore, each circuit component for preventing noise outflow is sandwiched between the circuit board 50 and the brush base 32 and does not receive any external force, so that no accident such as damage to the capacitor or short circuit occurs. .

A ground wire 59 is connected between the ground connection portion 58 of the circuit board 50 and the outer peripheral edge of the housing 21.

Power is supplied to the DC motor 20 via power cords (not shown) that are soldered to the respective power source connecting portions 56 and 57 of the circuit board 50 with a predetermined polarity.
In addition, since each power supply connection portion 56, 57 is provided near the corresponding polarity-side brush terminal, the positional relationship between the power supply connection portion and the brush connected thereto can be intuitively determined from the outside, and the power supply It is possible to prevent the polarity of the cord connected to the connection portion from being incorrect.

The DC power supplied to each power supply connecting portion passes through the noise prevention circuit formed on the circuit board 50, the brush terminal connecting portions 54 and 55, and the brush terminals 45 and 46, and the inner surface side of the brush base 32. Are supplied to the brushes 42, 43 of the.

Here, as shown in FIG. 7, for example, the pair of brushes 42 and 43 are two commutator pieces 30 of the rotor 26.
When abutting against a and 30b, a direct current flows through the coil 29a whose both ends are connected to the two commutator pieces, and the iron core 28a is magnetized to, for example, the N pole. Here, when one permanent magnet 23 has an N pole and the other permanent magnet 24 has an S pole, the iron core 28a receives a repulsive force from the permanent magnet 23 and an attractive force from the permanent magnet 24. Rotate clockwise (in FIG. 7).

The coil that receives power from the brushes 42 and 43 switches to the adjacent coil every time the rotor 26 rotates 120 degrees, so that the clockwise rotation of the rotor 26 continues. The outflow of the pulsed noise generated during the rotation to the power supply side is suppressed by the noise prevention circuit formed on the circuit board 50.

If the rotor does not rotate due to poor soldering of the noise prevention circuit, the brush base 32 can be repaired on the circuit board 50 without removing it from the housing 21.

Further, since there is no component for forming the noise prevention circuit in the motor body, the motor body can be shared when the noise prevention circuit is necessary and when it is unnecessary.

[0042]

Other Embodiments In the above embodiment, the receiving portion provided on the outer surface of the brush base was formed so as not to penetrate the inner surface side, but this receiving portion may be penetrated to the inner surface side.

In the above embodiment, the brush terminals are inserted through the terminal holes 52 and 53 formed through the circuit board 50. However, as in the circuit board 50 shown in FIG. 60 and 61 may be provided, and the brush terminal connecting portions 62 and 63 may be formed around the notch.

Further, the power cord connection to the power source connecting portion may be connected by screwing as shown in FIG. 9 instead of soldering. In this case, the circuit board 5
No. 0 power supply connection portions 56, 57 are provided with holes 66 for inserting the screws 65, and screw holes 67 corresponding to the holes 66 are provided on the outer surface side of the brush base 32, so that the power cords 68, 69 The stoppers 68a and 69a are brought into close contact with the power supply connecting portions 56 and 57 (or via a chrysanthemum) and screwed. By using the screw-fastening method in this way, it is possible to prevent the pattern peeling of the power supply connection portion. Further, in this way, both soldering and screwing can be coped with.

Further, as shown in FIG.
The power supply terminals 70 and 71 are projected from the power supply terminals 70 and 71, and the power supply connection portions 56 and 57 of the circuit board 50 are provided with terminal holes 72 and 73 for inserting the power supply terminals 70 and 71.
The power supply terminals 70, 71 inserted through the wires 2, 73 and the power supply connection portions 56, 57 may be soldered. In this case, the power cord may be directly soldered to the power terminals 70 and 71.

Further, in the above-mentioned embodiment, the present invention is applied to the DC motor which rotates the rotor by the magnetic action between the iron core magnetized by passing the current through the coil and the permanent magnet. The present invention can be similarly applied to a DC motor that rotates a rotor using a force that a coil receives from a magnetic field and a generator that uses the DC motor in reverse.

Further, in the above embodiment, the brush is attached to the tip of the brush support plate, but the present invention can be similarly applied to a DC motor having a brush integrated into a wire shape. Further, in the above-described embodiment, the noise prevention circuit is formed by the choke coil and the capacitor, but the present invention can be applied to a DC motor provided with the noise prevention circuit by only the capacitor.

[0048]

As described above, the DC motor of the present invention is provided with a pair of brushes connected to a pair of inner surface brushes, in which the brush base is provided with a receiving portion which is recessed from the outer surface toward the inner surface side. The terminal is projected from the outer surface, and the brush terminal connecting portion and the power source connecting portion are provided on one surface side in advance, and the circuit component forming the noise prevention circuit between the brush terminal connecting portion and the power source connecting portion is on the other surface side. The circuit board attached to the circuit board, the circuit components are accommodated in the receiving section, and
With the structure in which the brush terminal and the brush terminal connection part are connected and fixed to the outer surface of the brush base in a state where the other surface side is superposed on the outer surface of the brush base, the following effects are obtained. is there.

(1) Soldering of parts on the inner surface side of the brush base is not required, and defective contact of the brush due to scattering of the paste is eliminated.

(2) Even if there is a defective soldering of the circuit component, it is not necessary to remove the brush base from the housing, and the defective repair can be performed on the circuit board.

(3) Since the circuit parts are located between the brush base and the circuit board and do not receive external force,
No damage or short circuit accidents will occur.

(4) Since the power supply connection portion and the brush terminal can be provided at positions close to each other with the same polarity, the positional relationship between the internal brush and the power supply connection portion can be easily judged from the outside and the power cord The connection error can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of the present invention.

FIG. 2 is a perspective view of an embodiment.

FIG. 3 is a plan view of an embodiment.

FIG. 4 is an exploded perspective view of an embodiment.

FIG. 5 is an enlarged rear view of the main part of the embodiment.

FIG. 6 is an enlarged rear view of the main part of the embodiment.

FIG. 7 is a schematic diagram for explaining the operation of one embodiment.

FIG. 8 is a perspective view of a main part showing another embodiment of the present invention.

FIG. 9 is a perspective view of a main part showing another embodiment of the present invention.

FIG. 10 is a perspective view of an essential part showing another embodiment of the present invention.

FIG. 11 is a perspective view of a conventional DC motor.

FIG. 12 is an enlarged rear view of the main part of a conventional DC motor.

[Explanation of symbols]

 20 DC motor 21 Housing 23, 24 Permanent magnet 26 Rotor 32 Brush stand 36, 37 Receiving part 40, 41 Brush support plate 42, 43 Brush 45, 46 Brush terminal 50 Circuit board 52, 53 Terminal hole 54, 55 Brush terminal connection Part 56, 57 Power supply connection part L1, L2 Choke coil C1-C3 Capacitor

Claims (1)

[Claims] 1. A pair of brushes fixed to an inner surface of the brush base by rotatably supporting a rotor in the housing by a housing and a brush base fixed so as to close an opening surface of the housing. In a DC motor that rotates the rotor by a DC power supply supplied via a noise prevention circuit, a pair of brushes that are respectively connected to the pair of brushes on the inner surface side of the brush base and project to the outer surface of the brush base. A terminal, a pair of power supply connection portions for supplying power on one surface side, and a pair of brush terminal connection portions connectable to the pair of brush terminals, and the other power supply connection portion and brush terminals on the other surface side. Circuit parts forming the noise prevention circuit are attached between the pair of brush terminal connection parts and the other surface side is superposed on the outer surface of the brush base. A circuit board connected to the pair of brush terminals and fixed to an outer surface of the brush base, and a circuit component attached to the other surface of the circuit board by being depressed from the outer surface of the brush base in an inward direction. A DC motor having a receiving part for receiving.