JP2014045539A - Noise suppressor for starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a noise suppressor 1 for starter capable of suppressing noise generated from a motor 4.SOLUTION: A noise suppressor 1 includes a conductor member 15 for adding an inductance between a motor lead wire 20 and a terminal bolt 12 on the motor side, an earth potential part 17 connected with the earth potential, capacitors C1, C2, C3 branched from the conductor member 15 and connected electrically between the earth potential part 17, and resistors R1, R2 connected in series with the capacitors C1, C2, and is incorporated in a resin package 19. Consequently, the impedance of a current path, through which a start current flows from a battery 3 to a motor 4 (impedance on the motor side from a brach point to a capacitor path branched from the conductor member 15) increases. In other words, the impedance of the capacitor path decreases relatively when the impedance of the current path increases, and thereby noise reduction effect is enhanced.

Description

  The present invention relates to a starter noise suppressing device for reducing noise generated from a starter motor.

In recent years, in order to reduce carbon dioxide emitted from vehicles and improve fuel efficiency, for example, when a signal stops at an intersection, a system that automatically stops the engine by cutting the fuel supply to the engine (generally an idling stop system) The number of vehicles equipped with is increasing. After the engine is stopped by the system, when the user performs a start operation, the starter is activated by an instruction of an ECU (electronic control unit) that controls the system to automatically restart the engine.
By the way, in a starter that uses a commutator motor, a spark is generated between the commutator and the brush when the motor rotates, and this spark causes noise in devices such as radio and navigation. May cause user discomfort.
In order to solve such a problem, Patent Document 1 discloses a technique for suppressing noise generated from a motor by providing a capacitor circuit in which at least one capacitor is connected in parallel with the motor.

German Patent Application Publication No. 102008001570

By the way, the capacitor used for noise countermeasures uses the property that “the higher the alternating current the higher the frequency, the easier it is to pass”, but it does not pass any AC current in the same way, but a high frequency above the frequency called the self-resonant frequency. In the region, the influence of the inductance component (equivalent series inductance) that the capacitor has becomes obvious, so that the impedance of the capacitor increases. For this reason, the capacitor circuit disclosed in Patent Document 1 has a problem that the noise suppression effect is reduced in a high-frequency region above a certain frequency.
The present invention has been made based on the above circumstances, and an object thereof is to provide a starter noise suppressing device capable of improving the suppression effect of noise generated from a motor.

(Invention according to Claim 1)
The present invention is connected to a power supply line through a motor lead wire, and receives a power supply from the battery through the power supply line to generate a rotational force, a terminal bolt on the battery side, and a terminal bolt on the motor side. It has an electrical contact that is connected to the power line, and an electromagnetic switch that opens and closes the electrical contact in conjunction with the solenoid on / off operation, and transmits the rotational force generated by the motor to the engine ring gear to start the engine A noise suppression device used for a starter that suppresses noise generated during operation of a motor, wherein the noise suppression device is electrically connected to a motor lead wire at one end and a terminal bolt on the motor side. A conductor member that is electrically connected to add inductance between the motor lead wire and the terminal bolt on the motor side, and the body of the motor An earth potential portion connected to the earth potential and at least one capacitor branched from the conductor member and electrically connected to the earth potential portion, the conductor member, the earth potential portion, and the capacitor Is disposed on a substrate and incorporated in an insulating package.

The noise reduction effect of the noise suppression device is related to the ratio of the impedance of the current path through which the starting current flows from the battery to the motor and the impedance of the capacitor path built in the noise suppression device. That is, it can be said that the noise reduction effect increases as the impedance of the motor current path (impedance on the motor side from the branch point to the capacitor path) increases and the impedance of the capacitor path decreases.
The noise suppression device of the present invention has a conductor member that adds inductance between the motor lead wire and the terminal bolt on the motor side, and a capacitor is connected between the conductor member and the ground potential portion. The impedance of the motor current path (the impedance on the motor side from the branch point to the capacitor path) increases. In other words, since the impedance of the capacitor path becomes relatively small as the impedance of the motor current path increases, the noise reduction effect is improved.

It is the circuit diagram which connected the noise suppression apparatus to the power supply line of the motor. It is a top view which shows the internal structure of a noise suppression apparatus. It is a side view of the starter which attached the noise suppression apparatus. It is the rear view which looked at the starter which attached the noise suppression apparatus from the rear end side.

  The mode for carrying out the present invention will be described in detail with reference to the following examples.

Example 1
First, the structure of the starter 2 provided with the noise suppression device 1 according to the present invention will be briefly described.
As shown in FIG. 3, the starter 2 includes a motor 4 that generates a rotational force when power is supplied from a battery 3 (see FIG. 1), and the rotational force of the motor 4 is transmitted to an engine ring gear (not shown). It consists of a pinion 5 for transmission and an electromagnetic switch 6 for intermittently supplying a current to the motor 4.
The motor 4 has a field element formed by arranging a plurality of permanent magnets or field windings at equal intervals in the circumferential direction on the inner circumference of a yoke 8 forming a magnetic circuit, and rotates on the inner circumference of the field element. A freely disposed armature, a commutator provided on the axially anti-pinion side (right side in FIG. 3) of the armature, and a brush 9 that slides on the outer periphery of the commutator as the armature rotates ( 1) and the like.

As shown in FIG. 1, the electromagnetic switch 6 includes a coil 10 that is excited from the battery 3 by turning on the starter switch SW, and includes a solenoid that forms an electromagnet when the coil 10 is excited. / Off operation, that is, the main contact MS is opened and closed according to the excitation / de-excitation of the coil 10.
The main contact MS is electrically connected between the set of fixed contacts 13 and the set of fixed contacts 13 connected to the power line of the motor 4 via the terminal bolts 11 on the battery side and the terminal bolts 12 on the motor side. The movable contact 14 is intermittently connected. When the movable contact 14 abuts on a set of fixed contacts 13 and the set of fixed contacts 13 is electrically connected, the main contact MS is closed, and the movable contact 14 is closed. The main contact MS is opened by separating from the pair of fixed contacts 13.

Next, the noise suppression device 1 will be described.
As shown in FIG. 1, the noise suppression device 1 includes a conductor member 15 that adds inductance to the power line of the motor 4 and an end frame 16 of the motor 4 that covers the rear end of the yoke 8 (see FIGS. 3 and 4). And the capacitors C1, C2, C3 and resistors R1, R2 electrically connected between the conductor member 15 and the ground potential portion 17. As shown in FIG. 2, the conductor member 15, the ground potential portion 17, the capacitors C1, C2, and C3 and the resistors R1 and R2 are disposed on the insulating substrate 18, and the resin package 19 ( (See FIGS. 3 and 4).
Note that ESL1, ESL2, ESL3 and ESR1, ESR2, ESR3 shown in FIG. 1 represent an inductance component (equivalent series inductance) and a resistance component (equivalent series resistance) included in the capacitors C1, C2, C3, respectively. , L2, L4, and L6 represent stray inductances of the capacitor paths that branch from the points A, B, and C in the figure, respectively.

The conductor member 15 is formed, for example, by punching from a copper plate into a shape shown in FIG. 2 and fixed on the surface of the substrate 18 by an adhesive or screwing. The conductor member 15 has an end on one end side and an end on the other end side taken out of the package 19, respectively, and a ring-shaped motor side connection terminal 15a is formed on the end on one end side. A ring-shaped switch-side connection terminal 15b is formed at the end of the switch.
As shown in FIG. 3, one end of the motor lead wire 20 drawn out from the end frame 16 to the outside of the motor 4 is electrically connected to the motor side connection terminal 15a. The other end of the motor lead wire 20 is electrically connected to the plus brush 9 inside the motor 4 (see FIG. 1). When a field winding is used for the field element of the motor 4, the motor lead wire 20 can be connected to the field winding.

The switch-side connection terminal 15b is electrically connected with a connection lead wire 21 connected to the terminal bolt 12 on the motor side. That is, the switch-side connection terminal 15 b is not directly connected to the motor-side terminal bolt 12 but is electrically connected to the motor-side terminal bolt 12 via the connection lead wire 21.
Similarly to the conductor member 15, the ground potential portion 17 is formed by punching a copper plate with a press, and is disposed at a substantially central portion of the substrate 18 as shown in FIG. Fixed to. In addition, a round hole 17a for passing the mounting bolt 22 (see FIG. 3) is formed in the center of the ground potential portion 17. Note that a printed circuit board on which the ground potential portion 17 is printed in a substantially central portion may be used.

As shown in FIG. 2, the capacitor C1 and the resistor R1 are connected in series between one end side (point A in the figure) of the conductor member 15 close to the motor side connection terminal 15a and the ground potential portion 17, and the capacitor C2 The resistor R2 is connected in series between one end side and the other end side of the conductor member 15 (point B in the figure) and the ground potential portion 17, and the capacitor C3 is a conductor member close to the switch side connection terminal 15b. 15 is connected between the other end side (point C in the figure) and the ground potential portion 17.
1 and 2, L1, L3, L5, and L7 represent inductance components of the conductor member 15. L1 is an inductance component on the motor side connection terminal 15a side from the point A in the figure, and L3 is In the figure, the inductance between point A and point B, L5 is the inductance between point B and point C in the figure, and L7 is the inductance part on the switch side connection terminal 15b side from point C in the figure.

The capacitor C1 has a capacitance of 4.7 nF, for example, and reduces noise that becomes a problem in a radio frequency band (for example, 76 to 108 MHz) mainly used in FM broadcasting.
The capacitor C2 has a capacitance of 2.2 μF, for example, and reduces noise that becomes a problem in a radio frequency band (for example, 3 to 30 MHz) mainly used in shortwave broadcasting.
The capacitor C3 has a capacitance of 56 μF, for example, and reduces noise that becomes a problem in a radio frequency band (for example, 522 to 1602 kHz) mainly used in AM broadcasting.
The capacitors C1 and C2 having a small capacitance are chip capacitors (for example, multilayer ceramic chip capacitors), and the capacitor C3 having a large capacitance is an electrolytic capacitor, for example. A chip-type capacitor having a small electrostatic capacity has a smaller ESL than an electrolytic capacitor having a large electrostatic capacity, and thus is suitable for use in a high frequency band such as FM broadcasting or shortwave broadcasting.

When capacitors C1, C2, and C3 having different capacities are connected in parallel, a parallel resonance circuit of an inductor and a capacitor is generated at a frequency intermediate between the respective self-resonance points, and a phenomenon called anti-resonance occurs. May deteriorate (rise) and decrease the attenuation characteristics. Therefore, in the first embodiment, resistors R1 and R2 are connected in series with the capacitors C1 and C2 in order to reduce the combined impedance at the time of parallel resonance.
Capacitors C1, C2, and C3 and resistors R1 and R2 are each mounted on the surface of the substrate 18 by soldering or a conductive adhesive.

  As shown in FIG. 4, the noise suppression device 1 is fixed by fastening a mounting bolt 22 (see FIG. 3) to a pedestal 16 a provided integrally with the end frame 16 of the motor 4, and is taken out of the package 19. The motor lead wire 20 is electrically and mechanically connected to the motor side connection terminal 15a, and the connection lead wire 21 is electrically and mechanically connected to the switch side connection terminal 15b. By making direct contact with the pedestal 16 a or indirectly through the mounting bolt 22, the pedestal 16 a is electrically connected to the end frame 16 having a ground potential.

(Operation and Effect of Example 1)
In the noise suppression device 1 of the first embodiment, the motor lead wire 20 is connected to the motor side connection terminal 15a taken out of the package 19, and the connection lead wire 21 is connected to the switch side connection terminal 15b. The inductance of the wire 20 can be used as the impedance of the current path through which the starting current flows from the battery 3 to the motor 4. Further, the capacitor C1 branches from each point (point A, point B, point C in FIG. 1) of the conductor member 15 between the motor side connection terminal 15a and the switch side connection terminal 15b and between the ground potential portion 17 and the capacitor C1. , C2 and C3 are connected in parallel, the impedance of the motor current path (the impedance on the motor side from the branch point to the capacitor path branched from the conductor member 15) increases. In other words, since the impedance of the capacitor path becomes relatively small as the impedance of the motor current path increases, the noise reduction effect is improved.

In particular, the closer the branch point from the conductor member 15 to the capacitor path is to the motor lead wire 20 side, that is, the closer to the motor side connection terminal 15a, the smaller the amount of additional impedance due to the conductor member 15, and thus the closest to the motor side connection terminal 15a. It is more effective to use a chip capacitor having a small stray inductance capacity in the capacitor path branched from the point A (see FIGS. 1 and 2) of the conductor member 15.
In the first embodiment, the capacitor C3 having a large capacitance is arranged in the capacitor path branched from the point C of the conductor member 15 closest to the switch side connection terminal 15b to which the connection lead wire 21 is connected. Like the capacitor C1, the chip capacitor C2 is arranged in the capacitor path branched from the point C to the point C (point B shown in FIG. 2), so that the noise reduction effect can be enhanced in a wide frequency band.

  Furthermore, since the noise suppressing device 1 according to the first embodiment incorporates the conductor member 15 that adds inductance to the current path of the motor 4 in the package 19, it can be easily attached to the starter 2. Specifically, the package 19 can be fixed to the pedestal 16 a provided on the end frame 16 by fastening with the mounting bolts 22, and the motor side connection terminal 15 a and the switch side connection terminal 15 b are taken out of the package 19. Therefore, the connection with the motor lead wire 20 and the connection with the terminal bolt 12 on the motor side through the connection lead wire 21 can be facilitated. Thereby, in order to attach the noise suppression apparatus 1 to the starter 2, the structure change on the starter 2 side can be minimized. That is, since it is only necessary to provide the pedestal 16a on the end frame 16, it is highly compatible with parts with a conventional starter to which the noise suppression device 1 is not attached, and a significant cost increase can be avoided.

(Modification)
In the first embodiment, the capacitances of the capacitors C1, C2, and C3 are 4.7 nF, 2.2 μF, and 56 μF, respectively. However, these capacitances are merely examples, and it goes without saying that the capacitances can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1 Noise suppression apparatus 2 Starter 3 Battery 4 Motor 6 Electromagnetic switch 11 Battery side terminal bolt 12 Motor side terminal bolt 15 Conductor member 17 Ground potential part 18 Board | substrate 19 Package 20 Motor lead wire C1, C2, C3 Capacitor R1, R2 Resistance MS Main contact (electrical contact)

Claims (7)

A motor (4) that is connected to a power supply line via a motor lead wire (20) and receives a supply of electric power from the battery (3) through the power supply line to generate a rotational force;
It has an electrical contact (MS) connected to the power supply line via a terminal bolt (11) on the battery side and a terminal bolt (12) on the motor side, and the electrical contact ( MS) and an electromagnetic switch (6) for opening and closing,
A noise suppression device (1) used for a starter (2) for starting the engine by transmitting a rotational force generated in the motor (4) to an engine ring gear, and suppressing noise generated when the motor (4) is operated. ) And
The noise suppression device (1)
One end side is electrically connected to the motor lead wire (20), and the other end side is electrically connected to the motor-side terminal bolt (12) via a connection lead wire (21). (20) and a conductor member (15) for adding an inductance between the motor-side terminal bolt (12);
At least electrically connected between the ground potential portion (17) connected to the ground potential through the body of the motor (4) and the ground potential portion (17) branched from the conductor member (15). One capacitor (C),
The conductor member (15), the ground potential portion (17), and the capacitor (C) are arranged on a substrate (18) and are built in an insulating package (19). Noise suppression device for starters. In the starter noise suppression device (1) according to claim 1,
The conductor member (15) has an end on the one end side and an end on the other end side taken out of the package (19), and the motor lead wire (20) is connected to the end on the one end side. And a switch side connection terminal (15b) connected to the connection lead wire (21) is formed at the end of the other end side. Starter noise suppression device. In the starter noise suppression device (1) according to claim 1 or 2,
The capacitor (C) is connected in parallel between the conductor member (15) and the ground potential part (17), and has a small capacitance (C1, C2) having a small capacitance, A large capacitor (C3),
A branch point that branches from the conductor member (15) to the small capacitor (C1, C2) is a first branch point (point A, point B), and the conductor member (15) branches to the large capacitor (C3). When the branch point to be called the second branch point (C point),
The first branch point (point A, point B) is provided on one end side of the conductor member (15) from the second branch point (point C), and the small capacitors (C1, C2) are: A starter noise suppression device, which is a chip-type capacitor. In the starter noise suppression device (1) according to claim 3,
The small-capacitance capacitors (C1, C2) are a first chip-type capacitor (C1) and a second chip-type capacitor connected in parallel between the conductor member (15) and the ground potential portion (17). (C2)
The first chip capacitor (C1) has a smaller capacitance than the second chip capacitor (C2), and branches from the conductor member (15) to the second chip capacitor (C2). The starter noise suppressing device is connected to the ground potential portion (17) on one end side of the conductor member (15) from a branch point (point B). In the starter noise suppression device (1) according to claim 3 or 4,
A starter noise suppressing device, wherein a resistor (R) is connected in series to at least one of the small capacitor (C1, C2) and the large capacitor (C3). In the starter noise suppression device (1) according to claim 5,
The starter noise suppressing device, wherein the capacitor (C) and the resistor (R) are mounted on the substrate (18) by soldering or a conductive adhesive. In any one starter noise suppression device (1) according to claims 1-6,
The package (19) is fixed to a pedestal (16a) provided on an end frame (16) constituting a part of the body of the motor (4), and the ground potential portion (17) is connected to the pedestal (16). The starter noise suppressing device, wherein the starter noise suppressing device is electrically connected to the end frame (16) in direct or indirect contact with 16a).

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