JPH09273464A - Starter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent thermal insulation breakage without using any flame resistant material in a short time rating one. SOLUTION: A fuse 8, which fuses at the predetermined temperature so as to shut off electric current, is arranged between a relay terminal 6 in a direct current motor device 1 and a connecting terminal 9 in a solenoid switch device 7. When the predetermined temperature, at which the fuse 8 fuses, is properly set, the fuse temperature is quickly increased so that the fuse 8 fuses so as to shut off the electric current even when a continuous operation condition is made because of a defect such as welding of a movable contact 37 to a B terminal and an M terminal and welding of a contact mechanism on the outside of a starter or when an overcurrent conducting condition is made because of locking of a rotor 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a starter for starting an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, a thermal weak point is provided in an energizing circuit inside a starter so that the energizing part does not reach a very high temperature and thermal breakdown does not occur.
No. 2 discloses this. In the above invention, the brush pigtail forming the energizing circuit inside the starter also has a fuse action for thermal fusing. With this configuration, when the temperature of the energizing circuit becomes high due to continuous energization, the brush pigtail is melted and the high temperature of the energizing circuit can be prevented, but it is not always possible to obtain good results.

[0003]

In the above prior art, first, the plus side pigtail is provided with an insulating bush in order to seal the inside and outside of the motor and to ensure insulation from grounding parts such as brackets and yokes. ing. This insulating bush is usually made of a combustible material such as rubber in view of the function of parts, and if the pigtail melts, the heat of the melting deteriorates the insulating bush itself, which may cause dielectric breakdown. For example, when the pigtail (fuse) is copper and the insulating bush is rubber, the melting temperature of copper is 1000 ° C and the carbonization temperature of rubber is about 200 to 300 ° C. In the case of this combination, even if the abnormal operation of continuous energization is interrupted by melting the pigtail, the insulating bush may be deteriorated by the heat of melting at that time.

Further, in the case of the minus side pigtail,
Although there is no insulating bush, it is not always preferable because the surrounding insulating material may be deteriorated by the melting heat generated in the motor.

It is an object of the present invention to easily provide a starter in which thermal insulation does not reach the inside of the motor or the electromagnet switch device even when the energizing circuit is in an abnormal state of continuous energization.

[0006]

[Means for Solving the Problems]

(1) The above object is provided with a DC motor device and an electromagnet switch device, and the DC motor device is provided with a rotor, an armature core around which an armature coil is wound, and the rotor. The electromagnet switch device includes a commutator electrically connected to the armature coil, a first brush on the positive side that supplies power to the commutator, and a second brush on the negative side, and the electromagnet switch device includes an external power source. A movable terminal that electrically connects and disconnects a first terminal, a second terminal electrically connected to the first brush, and a connection between the first terminal and the second terminal. A starter having a current cutoff mechanism that melts and cuts off power supply at a predetermined temperature, which is a conductive path connecting between the lead wire end of the first brush and the second terminal, and DC motor device and electromagnet switch device It is accomplished by a starter, characterized in that provided outside. When the internal combustion engine is started, for example, by turning on a key switch, the first terminal of the electromagnet switching device electrically connected to the external power source and the first brush of the DC motor device are electrically connected. The movable contact that connects and disconnects the second terminal that is present is closed to connect these two terminals, and the external power source, the first terminal,
A current flows through an electric circuit including the movable contact, the second terminal, the first brush, the commutator, the coil, and the second brush.
In other words, the current introduced from the external power supply into the starter is
The first terminal of the electromagnet switch device → the movable contact → the second terminal → the first brush of the DC motor device → the first of the commutators
Segment of the commutator in contact with the second brush of the commutator → flow with the second brush,
Further, for example, the electric current flows from the plate electrically connected to the second brush to the external power source via the end bracket. In this way, the rotor and rotary shaft of the DC motor device are rotated. After starting once, by returning to the key switch OFF, the movable contact is opened, the flow of current is interrupted, and the rotation of the DC motor device is stopped. here,
In the present invention, a current cutoff mechanism that melts at a predetermined temperature is provided in the conductive path connecting the lead wire end of the first brush and the second terminal. And, in the normal starter operation as described above, the time length is at most several seconds.
It is a short time of ten and several seconds, and the current interruption mechanism does not work. However, by appropriately setting the predetermined temperature at which the current cutoff mechanism melts, for example, a continuous operation state is caused due to problems such as welding of the movable contact and the first and second terminals and welding of the contact mechanism outside the starter. Even if it is assumed that the rotor is locked and the rotor is in an overcurrent energized state, the current cutoff mechanism becomes hot outside the DC motor device and electromagnet switch device in a short time and melts down. It can be configured to cut off current. As a result, the energization circuit can be easily and reliably shut off without affecting flammable materials such as insulators that are often used inside the DC motor device and the electromagnet switch device.

(2) In the above (1), preferably,
The current cutoff mechanism is a fuse, and is achieved by a starter characterized in that the current path cross-sectional area of any conductor including the lead wire is minimized. Thus, when the electric circuits are all formed of the same member, the current cutoff mechanism having the smallest current path cross-sectional area surely blows out the earliest. Therefore, the current can be surely cut off earlier than the other combustibles in the electric circuit are heated to cause thermal insulation breakdown.

(3) In the above (1), and preferably, the connection terminal provided in the electromagnet switch device and electrically connected to the second terminal, and the first terminal provided in the DC motor device. There is provided a starter characterized by further comprising a relay terminal electrically connected to the brush, and wherein the current interruption mechanism is provided between the connection terminal and the relay terminal. By providing a current cutoff mechanism between the connection terminal provided at the extraction port from the electromagnet switch device and the relay terminal provided at the extraction port from the DC motor, the current cutoff mechanism can be provided for the DC motor device and the electromagnet switching device. It can be reliably placed outside.

(4) In the above (1), and preferably, the connection terminal provided in the electromagnet switch device and electrically connected to the second terminal, and the first terminal provided in the DC motor device. The starter is characterized by further comprising a relay terminal electrically connected to the brush, and the current interruption mechanism is integrally formed with the connection terminal.

(5) In the above (1), and preferably, the connection terminal provided in the electromagnet switch device and electrically connected to the second terminal, and the first terminal provided in the DC motor device. And a relay terminal electrically connected to the brush, and the current cutoff mechanism is formed integrally with the relay terminal.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a partially cutaway side view showing the entire structure of the starter of this embodiment. In FIG. 1, a starter 100 is a so-called two-shaft starter, and includes a DC electric motor device 1, an output shaft 71 for transmitting a rotational force from the DC electric motor device 1 to a ring gear 70 of an internal combustion engine, and the output shaft 71. An overrunning clutch device 72 that is slidably fitted on the shaft and to which the rotational force from the output shaft 71 is transmitted.
An electromagnet switch device 7 including an electromagnet (not shown) and a plunger rod 73 that is attracted and driven when the electromagnet is excited; one end is engaged with the plunger rod 73 and the other end is engaged with the overrunning clutch device 72. And a shift lever 74.

The DC motor device 1 includes a rotor 5 having an armature coil (not shown) wound around an armature core and a commutator 15 electrically connected to the armature coil, and a rotor 5 made of metal. End bracket 11, a metal plate 2 fixed to the bottom surface of the end bracket 11, and a negative brush holder 13 directly fixed to the plate 2.
The negative brush 3 slidably held by the negative brush holder 13 and in contact with the commutator 15, the positive brush holder 14 fixed on the plate 2 via the insulating plate 24, and the positive brush A positive brush 4 slidably held by the holder 14 and abutting on the commutator 15 and a relay terminal 6 electrically connected to the positive brush 4 are provided. The negative brush 3 and the positive brush 4 are pressed against the commutator 15 by push springs (not shown), so that the commutator 15
Abutting on each brush side segment. The negative brush 3 is directly connected to the plate 2 by the lead wire 23, and the positive brush 4 is connected to the inner end of the DC motor device 1 of the relay terminal 6 by the lead wire 34.
The relay terminal 6 is held by an elastic insulating bush 16 and is fixed to the end bracket 11 via this insulating bush 16, and one end of the relay terminal 6 projects outside the DC motor device 1.

On the other hand, the electromagnet switching device 7 is also electrically connected to the positive terminal of the external power source (battery) B.
Via the terminal 17, the M terminal 27 electrically connected to the positive brush 4 of the DC motor device 1, the movable contact 37 capable of connecting / disconnecting the B terminal 17 and the M terminal 27, and the nut 67. A connection terminal 9 fixed to the M terminal 27 and electrically connected to the M terminal 27, an insulating component 47 for surrounding insulation of the B terminal 17 and the M terminal 27, and an insulating component for surrounding insulation of the movable contact 37. 57 and 57. The opening / closing operation of the movable contact 37 is performed by an electromagnet built in the electromagnet switch device 7, and is performed simultaneously with the suction operation of the plunger rod 73.

Further, a conductive path connecting between the end portion of the lead wire 34 of the positive brush 4 of the DC motor device 1 and the M terminal 27 and outside the DC motor device 1 and the electromagnet switch device 7, specifically, Specifically, a fuse 8 is provided between the relay terminal 6 of the DC motor device 1 and the connection terminal 9 of the electromagnet switch device 7 so as to melt and cut off the current at a predetermined temperature. That is, the fuse 8 is reliably connected to the positive brush 4 via the relay terminal 6 and the electrical connection to the M terminal 27 via the connection terminal 9 so that the fuse 8 is securely connected.
It is arranged outside the switch device 7 and can perform the cutoff function without affecting the devices and members in the DC motor device 1 and the switch device 7.

The operation and effect of the starter 100 having the above structure will be described below. When the internal combustion engine is started, for example, a key switch (not shown) is turned on to excite the electromagnet, so that the B terminal 17 of the electromagnet switch device 7 electrically connected to the external power source and the positive brush 14 of the DC motor device 1 are connected. The movable contact 37 for connecting / disconnecting the M terminal 27 electrically connected to is closed to connect these two terminals 17 and 27, and the external power source, the B terminal 17, the movable contact 37, the M terminal 27, Positive brush 14, commutator 1
An electric current flows through an electric circuit including the coil 5, the negative brush 13, and the negative brush 13. That is, the current introduced from the external power source into the starter 100 is the B terminal 17 of the electromagnet switching device 7 →
Movable contact 37 → M terminal 27 → Connection terminal 9 → Fuse 8 → Relay terminal 6 of the DC motor device 1 → Lead wire 34 → Positive brush 14 → Segment of the commutator 15 in contact with the positive brush 14 → Coil → Commutator Segment of 15 that contacts negative brush 13 → negative brush 13 →
Lead wire 23 → plate 2 → end bracket 11
→ It flows with an external power supply. In this way, the rotor 5 and the rotary shaft of the DC motor device 1 are rotated. After starting once, by returning the key switch to OFF, the attraction force of the electromagnet is released, the movable contact 37 is opened, the flow of current is interrupted, and the rotation of the DC motor device 1 is stopped.

Here, in the starter 100 of this embodiment, a fuse 8 that blows at a predetermined temperature is provided between the relay terminal 6 and the connection terminal 9. In the starter operation for starting the normal engine as described above, the fuse 8 does not function because its time length is at most a few seconds to a dozen seconds. However, by appropriately setting the predetermined temperature at which the fuse 8 melts, the fuse becomes hot and melts in a short time, and the current can be easily and surely cut off. For example, when a continuous operation state occurs due to a problem such as welding of the movable contact 37 to the B terminal 17 or M terminal 27 or welding of a contact mechanism other than the starter 100, or when the rotor 5 is locked and an excessive current is supplied. Even if the case is assumed to be virtual, this makes it possible to use insulators that are often used inside the DC motor device 1 and the electromagnet switch device 7 (for example, the insulating plate 24, the insulating bush 16, the insulating parts 47, 57, etc.). ) Or a combustible conductive material such as a combustible conductive material can be prevented from dielectric breakdown. Therefore, peripheral parts and the internal combustion engine body can also be protected from dielectric breakdown. In other words, it is not necessary to pay attention to the heat resistance of peripheral devices more than necessary, which may cause a cost increase like when using a flame-retardant material for the insulator, or when designing for a long time rating. As described above, the entire starter 100 does not become large and heavy.

Although the M terminal 27 of the electromagnet switch device 7 and the fuse 8 are connected via the connection terminal 9 in the above embodiment, the present invention is not limited to this. That is, the fuse 8 and the M terminal 27 may be directly connected.
In this case, a similar effect is obtained. Further, in the above embodiment, the positive brush 14 of the DC motor device 1 and the fuse 8 are connected via the relay terminal 6, but the present invention is not limited to this. That is, the fuse 8 and the positive brush 14 may be directly connected. In this case, a similar effect is obtained.

A second embodiment of the present invention will be described with reference to FIGS. This embodiment is an embodiment in which a fuse and a connection terminal are integrated. FIG. 2 is a partially cutaway side view showing a main part structure of the starter 200 according to the present embodiment, and FIG. 3 is an enlarged view seen from the direction A in FIG.
Members equivalent to those in the first embodiment are denoted by the same reference numerals. 2 and 3, the main difference between the starter 200 and the starter 100 of the first embodiment is the fuse installation structure. That is, the fuse portion 209A is integrally provided on the connection terminal 209 of the electromagnet switch device 7,
The connection terminal 209 and the relay terminal 6 are connected by the lead wire 244. At this time, the relationship between the lead wire 244 and the fuse portion 209A of the connection terminal 209 is configured as follows. That is, although the lead wire 244 and the connection terminal 209 are both made of copper, the lead wire 244 is
While the current path cross-sectional area is set so that the current density is about 27 A / mm ^{2 under} the load (about several seconds to several tens of seconds) when the starter is normally started, the fuse portion 209A is
The current path cross-sectional area is set so that the current density is about 32 A / mm ² with this load. In other words, the fuse portion 209A has a smaller current path cross-sectional area than the lead wire 244 so that the current concentrates on the narrower cross section. In relation to other members, the B terminal 17 described above is used. ~ Positive brush 14 ~ Commutator 15 ~ Negative brush 13 ~ End bracket 11 When a current is passed through the current circuit, the temperature is the first to rise and the fuse is blown. Therefore, when all the members forming these current circuits are formed of the same member such as copper, the fuse portion 209A has a current path cross-sectional area larger than that of any conductor current path cross-sectional area including the lead wire 244. The minimum. Other configurations are almost the same as those of the first embodiment.

Also according to this embodiment, the connection terminal 2
Due to the interruption function of the fuse portion 209A of 09, the same effect as that of the first embodiment is obtained. That is, specifically, assuming that the M terminal 27 of the electromagnet switching device 7 and the connection terminal 6 of the DC motor device 1 are connected only by the lead wire 244, the movable contact 37 is welded to the B terminal 17 and the M terminal 27. When assuming a continuous operation state due to a problem such as welding of a contact mechanism outside the starter 200 or the starter 200, the current density of the lead wire 244 is about 27 A / mm ² and about 150 A / mm ^2.
Fuse in seconds. During this time, the temperature of each member of the starter 200 continues to rise and reaches about 500 ° C. in the vicinity of the positive brush 4 immediately before the melting of the lead wire 244, but the high temperature of 500 ° C. causes various insulating parts (insulating plate 24, The temperature is extremely difficult to completely prevent dielectric breakdown of combustible materials such as the insulating bush 16, the insulating parts 47 and 57) and combustible conductive members. However, in the starter 200 of this embodiment, since the fuse portion 209A is interposed,
Even in the above hypothetical case, the current density of the fuse portion 209A is about 32 A / m before reaching 500 ° C.
It becomes m ² and melts in about 120 seconds, so that the dielectric breakdown as described above can be completely prevented. Similarly, assuming that the M terminal 27 and the relay terminal 6 are connected only by the lead wire 244 and the rotor 5 is locked and is in the overcurrent conducting state, the current density of the lead wire 244 is about 90 A / mm. It becomes ² . Then, from the time of locking to the melting of the lead wire 244, the above-described continuous energization state is obtained. However, the starter 200 of the present embodiment
In this case, since the fuse portion 209A is interposed, and the current density of the fuse portion 209A becomes about 110 A / mm ² , the fuse portion 209A always blows out in about 10 seconds before the lead wire 244. Destruction can be completely prevented.

A third embodiment of the present invention will be described with reference to FIG. This embodiment is an embodiment in which a fuse and a relay terminal are integrated. The same members as those in the second embodiment are designated by the same reference numerals. FIG. 4 is an enlarged view showing the main part structure of the starter according to this embodiment, and is a view corresponding to FIG. 3 in the second embodiment. In FIG. 3, the main difference from the starter 200 of the second embodiment is the fuse installation structure. That is, the fuse portion 306A is integrally provided on the relay terminal 306 of the DC motor device 1, and the relay terminal 306 and the connection terminal 9 are connected by the lead wire 344. At this time, the relationship between the lead wire 344 and the fuse portion 306A of the relay terminal 306 is the same as the relationship between the lead wire 244 and the fuse portion 209A of the connection terminal 209 of the second embodiment. That is, although the lead wire 344 and the relay terminal 306 are both made of copper, the lead wire 344 has a current density of about 27 A / mm ^{2 under} a load (about several seconds to several tens of seconds) when the starter normally starts. While the path cross-sectional area is set, the fuse portion 306A sets the current path cross-sectional area so that the current density is about 32 A / mm ^{2 under} this load. In other words, this fuse part 3
06A has a current path cross-sectional area smaller than that of the lead wire 344 so that the current concentrates on a cross section that is narrower than that of the lead wire 344. Further, in relation to other members, the above-described B terminal 17-positive brush 14- Commutator 15-Negative brush 13
~ When a current is applied to the current circuit including the end brackets 11, the temperature rises first and the fuse is blown. Therefore, when all the members forming these current circuits are formed of the same member such as copper, the fuse portion 306A is connected to the lead wire 3
The current path cross-sectional area is the smallest than any conductor current path cross-sectional area including 44. Other configurations are almost the same as those of the second embodiment.

Also according to this embodiment, the relay terminal 3
Due to the cutoff function of the fuse portion 306A of 06, the same effect as that of the second embodiment is obtained. That is, specifically, assuming that the connection terminal 9 of the electromagnet switch device 7 and the positive brush 4 of the DC motor device 1 are connected only by the lead wire 344, the movable contact 37 and the B terminal 17 and the M terminal 27 are connected. When assuming a continuous operation state due to problems such as welding and welding of the contact mechanism outside the starter, the lead wire 3
No. 44 has a current density of about 27 A / mm ² and melts in about 150 seconds. During this time, the temperature of each member of the starter continues to rise and reaches, for example, about 500 ° C. near the positive brush 4 just before the lead wire 344 is melted, but the high temperature of 500 ° C. causes various insulating parts (insulating plate 24, insulating The temperature is extremely difficult to completely prevent dielectric breakdown of combustible materials such as the bush 16, the insulating parts 47 and 57) and combustible conductive members. However, since the fuse portion 306A is interposed in the starter of the present embodiment, even in the above-described virtual case, the current density of the fuse portion 306A becomes about 32 A / mm ² before each portion reaches 500 ° C.
Since the fusing occurs in 0 seconds, the above dielectric breakdown can be completely prevented. Similarly, when the connection terminal 9 and the positive brush 4 are connected only by the lead wire 344 and the excessive current energization state in which the rotor 5 is locked is assumed, the current density of the lead wire 344 is about 90 A / mm ² , and the fuse is The current density of the portion 306A is about 110 A / mm ² . Then, from the time of locking to the melting of the lead wire 244, the above-described continuous energization state is obtained. However, similar to the above, the fuse portion 209A is interposed, and the current density of the fuse portion 209A is about 110 A / mm.
^Since it becomes ² and melts before the lead wire 244 in about 10 seconds, the dielectric breakdown as described above can be completely prevented in this case as well.

[0022]

According to the present invention, since a current cutoff mechanism that melts at a predetermined temperature is provided between the first brush and the second terminal of the electric circuit, a predetermined temperature at which the current cutoff mechanism melts is cut. By setting it appropriately, for example, in the case of continuous operation due to problems such as welding of the movable contact and the first and second terminals or welding of the contact mechanism outside the starter, or when the rotor locks and excessive current is applied. Even when the above situation is assumed, it is possible to configure so that the current cutoff mechanism becomes high temperature in a short time outside the DC motor device and the electromagnet switch device to melt and cut off the current. . Therefore, it is possible to prevent dielectric breakdown of insulators and the like that are often used inside the DC motor device and the electromagnet switch device. Therefore, it is possible to prevent adverse effects on peripheral components and the internal combustion engine body. At this time, there is no increase in cost as in the case of using a flame-retardant material for the insulator, and no increase in size or weight of the entire starter as in the case of designing for a long time.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing an entire structure of a starter according to a first embodiment of the present invention.

FIG. 2 is a partially cutaway side view showing a structure of a main part of a starter according to a second embodiment of the present invention.

FIG. 3 is an enlarged view seen from the direction A in FIG.

FIG. 4 is an enlarged view showing a main part structure of a starter according to a third embodiment of the present invention.

[Explanation of symbols]

 1 DC Motor Device 2 Plate 3 Negative Brush (Second Brush) 4 Positive Brush (First Brush) 5 Rotor 6 Relay Terminal 7 Electromagnetic Switch Device 8 Fuse 9 Connection Terminal 11 End Bracket 13 Negative Brush Holder 14 Positive brush holder 15 Commutator 16 Insulation bush 17 B terminal (first terminal) 23 Lead wire 24 Insulation plate 27 M terminal (second terminal) 34 Lead wire 37 Moving contact 47 Insulation component 57 Insulation component 67 Nut 100 Starter 200 Starter 209 Connection Terminal 209A Fuse Part 244 Lead Wire 306 Relay Terminal 306A Fuse Part 344 Lead Wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Sakaga 2520 Takaba, Hitachinaka City, Ibaraki Prefecture, Ltd. Inside the Automotive Equipment Division, Hitachi, Ltd. Hitachi, Ltd. Automotive Equipment Division

Claims (5)

[Claims] 1. An armature core provided with a DC motor device and an electromagnet switch device, wherein the DC motor device is provided in a rotor and around which an armature coil is wound, and the armature provided in the rotor. A commutator electrically connected to the coil,
The electromagnet switching device has a first brush on the plus side and a second brush on the minus side for supplying power to the commutator, and the electromagnet switch device includes a first terminal electrically connected to an external power source, and the first terminal. In a starter having a second terminal electrically connected to the first brush and a movable contact for connecting / disconnecting the first terminal and the second terminal, the starter melts and melts at a predetermined temperature to supply power. A current interrupting mechanism for interrupting the current is provided as a conductive path connecting the lead wire end of the first brush and the second terminal and outside the DC motor device and the electromagnet switch device. Starter characterized by. 2. The starter according to claim 1, wherein the current cutoff mechanism is a fuse, and the current path cross-sectional area of any of the conductors including the lead wire is the smallest. Starter to do. 3. The starter according to claim 1, wherein the electromagnet switch device has a connection terminal electrically connected to the second terminal, and the DC motor device has an electrical connection to the first brush. And a relay terminal electrically connected to each other, and the current interruption mechanism,
A starter provided between the connection terminal and the relay terminal. 4. The starter according to claim 1, wherein the electromagnet switch device is provided with a connection terminal electrically connected to the second terminal, and the DC motor device is provided with an electrical connection to the first brush. Further connected to the relay terminal, and the current cutoff mechanism,
A starter formed integrally with the connection terminal. 5. The starter according to claim 1, wherein the electromagnet switch device is provided with a connection terminal electrically connected to the second terminal, and the DC motor device is provided with an electric connection to the first brush. Further connected to the relay terminal, and the current cutoff mechanism,
A starter formed integrally with the relay terminal.