JPS6114632Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement in an engine starting device, particularly a protection device for preventing re-engaging during inert rotation.

Conventionally, there has been a device of this type as shown in FIGS. 1 and 2. In the figure, 1 is battery, 2 is
is a key switch, 3 is a protection relay assembly, 4 is an auxiliary switch, 4a is a coil, 4b is a contact, 5 is a protection relay, 5a is a coil, 5b is a contact, 6 is a magnetic switch, 6a is an absorption coil, 6b is a holding A coil, 6c is a main contact, 6d is a cap assembly surrounding the main contact 6c of the magnetic switch, and 7 is a DC motor to which the magnetic switch 6 is attached.

In the conventional device having the above configuration, the key switch 2 is closed, an energizing current flows through the coil 4a and the contact 5b, and the normally open contact of the contact 4b is closed.
The magnetic switch 6 is energized and the main contact 6c
is closed, and main current is applied from the battery 1 to the DC motor 7 to start an engine (not shown). After the start, the key switch 2 is opened, the contact 4b of the auxiliary switch 4 is reset, the magnet switch 6 is deenergized, and the cranking operation of the starter motor to the engine (not shown) is released. By the way, when the engine stalls again after the engine starts, if the driver closes the key switch 2 again, the DC motor 7 is rotating due to inertia, and in this state, the DC motor 7 A meshing impact force is generated in the electric motor 7. For this purpose, a protective relay 5 is provided, and the inert rotation counter electromotive force causes a current to flow through the coil 5a and the contact 4b, which releases the contact 5b and closes the key switch 2, thereby providing assistance. Switch 4 is prevented from being energized.

By the way, since the conventional starting motor protection device is configured as described above, the protective relay assembly 3
In this case, an auxiliary switch 4 and a protective relay 5 for detecting the state of inertia rotation are required, which not only makes the device complicated and expensive, but also has somewhat insufficient sensitivity for detecting the state of inertia rotation. Ta.
In order to solve this drawback, a protection device shown in FIGS. 3 and 4 is known.

That is, in the figure, 8 is a magnetic switch, 8a is a normally closed contact, 8b is a main contact, 8c is an attraction coil, 8d is a holding coil, 9 is a protection relay, 9
A is a normally closed contact, and 9b is a coil. Descriptions of other symbols are omitted as they are the same as those in the apparatus shown in FIG.

In the starter motor having the above configuration, when the key switch 2 is closed, the coils 8c and 8d of the magnetic switch 8 are energized via the normally closed contact 9a, the main contact 8b is closed, and the main current is supplied from the battery 1. The DC motor 7 is energized. After the engine (not shown) is started by the above operation, the key switch 2 is released and the energization of the starting motor 7 is released.
If the primary engine stalls immediately after starting,
Since the DC motor 7 rotates by inertia, the coil 9b is energized by the counter electromotive force and the contact 9a is opened. Therefore, even if the key switch 2 is closed for restarting, the magnetic switch 8 is not energized, and it is therefore possible to prevent problems caused by re-engaging of the engine during inert rotation. Figure 4 is the third
2 is a partial cross-sectional view of the magnetic switch 8 shown in FIG.
10 is a cap assembly of magnetic switch 8,
Reference numeral 11 denotes a cap that is molded mainly from Bakelite, and the contact 8a is integrally insert-molded therein.

Reference numeral 12 denotes an electrically conductive contact, and as shown in the figure, both ends are in sliding contact with the normally closed contact 8a in the stationary position, and the coil 8
The movable contact 12 becomes the main contact 8b due to the biasing forces c and 8d.
and closes the main current circuit.

However, in such a device, a voltage is applied to the coil 12d the moment the key switch 2 is closed, and there is a possibility that the contact 12a will be cut off.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above, and includes a protective relay that energizes the back electromotive force during inert rotation of the DC motor 7 through the normally closed contact of the magnetic switch. At the same time, insert a resistor between the normally open contacts of the protective relay,
When the protective relay is energized, the contacts of the protective relay directly cut off the energizing circuit of the magnetic switch by closing the key switch, which simplifies the device, and when re-energizing the starting motor during inert rotation. It is an object of the present invention to provide a protection device for a starting motor that can prevent accidents that are about to occur and prevent malfunctions.

This invention will be explained below with reference to FIG. 5, which is an example.

Figure 5 shows a structure in which a resistor is inserted in series on the load side of the protective relay coil in the circuit shown in Figure 3 to increase the impedance of the protective relay circuit when the key switch is turned on, in order to stabilize the protection relay's instantaneous operation. There is. That is, 12 is a protection relay, 12a is a normally closed contact, 12b is a normally open contact, and a resistor 12c is connected to both ends. A coil 12d is energized by a counter electromotive force during inert rotation of the starting motor 7 through a normally closed contact 8a, and is grounded via a resistor 12c when the starting motor is stopped. Considering the embodiment of the above configuration as a DC circuit, its operation will be explained using FIG. 6. When the key switch 2 is closed, the normally closed contact 12 is
DC current is applied to the DC motor 7 via the coil 8c and the coil 8c. In this case, the voltage of the battery 1 is 24V, and the voltage of the coil 8c is 0.2Ω.
It has a DC resistance of 0.02Ω, and the coil 12d has a resistance value of about 1Ω, so at point A in the figure, the resistance is about 1Ω.
A voltage of 2.2V is generated. In this case, the contact 8a is closed at the moment the key switch is closed, and the voltage at point A is applied to the coil 12d. Here, the attraction voltage of the coil 12d is generally 0.4 to 0.6V, and the application of this voltage at point A causes the coil 12d to operate and cause a problem such as cutting off the contact 12a. Accordingly, the energizing voltage of the coil 12d (ie, the voltage across the coil) is lowered to prevent malfunction. In addition, after turning on the key switch 2, the contact 8a
Due to this release, the voltage at point A is not applied during cranking of the engine (not shown). Next, after the key switch 2 is opened, the magnetic switch 8 returns and the contact 8a returns to the normally closed state. Immediately after the above return, the DC motor 7 is rotating at high speed due to inertia, and in this case, it has been confirmed through experiments that a back electromotive force of about 20 V is generated at point A.

The above voltage is applied to the coil 12d and the resistor 12c via the contact 8a, cutting off the normally closed contact 12a and closing the normally open contact 12b. Therefore, resistor 12c
is grounded, full voltage is applied to coil 12d,
The biased state is maintained up to a considerably low inertia rotational speed region. The release voltage of the coil 12d is 0.1~
The voltage is 0.15V, and the normally closed contact 12a returns and closes at this voltage. In this manner, when the restart is possible, the rotational speed of the DC motor has decreased to a speed that does not cause destruction due to re-engaging. Furthermore, FIG. 7 shows another embodiment in which a backflow prevention diode is added to increase the sensitivity of the inertia rotation detection circuit. In the figure, 13 is a diode, and the back electromotive force of the DC motor 7 is consumed in the coil 12d via the contact 8a, so that the inertial rotation protection function with sufficient inertial rotation detection sensitivity can be obtained. I can do it.

As described above, this invention consists of a first coil that can be energized when the engine starting switch is closed, and a normal coil that is closed by the energization of the first coil to form an energizing circuit to the starting motor. an open contact, and a contact connected to the normally open contact and connected to the starting motor,
a first switch having a first normally closed contact that is opened when the first coil is energized; a second coil connected in series with the start switch and the first coil and capable of opening when the second coil is energized;
A normally closed contact and a second normally closed contact are attached to each other,
The conventional auxiliary switch is equipped with a second switch having a second normally open contact that is closed when the second coil is energized, and a resistor connected between the second normally open contact. This has the effect of being able to be abolished, eliminating the fear of malfunction, and making the device smaller, lighter, and cheaper.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of a conventional device, Fig. 2 is a side view of a starting motor to which the protection relay shown in Fig. 1 is connected, Fig. 3 is a circuit diagram showing another conventional device, and Fig. 4 is a side view of a starting motor to which the protection relay of Fig. 1 is connected.
5 is a circuit diagram showing an embodiment of this invention, and FIG.
FIG. 7 is a DC equivalent circuit diagram showing another embodiment of this invention. In the figure, 1 is a battery, 2 is a key switch, 3 is a protective relay assembly, 4 is an auxiliary switch, 5 is a protective relay, 6 is a magnetic switch, 7 is a DC motor, 8 is a magnetic switch, and 8a is a normally closed contact. ,
9 and 12 are protective relays, 12a is a normally closed contact, 1
2b is a normally open contact, 12c is a resistor, and 13 is a diode. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] a first coil that can be energized by closing a starter switch of the engine; a normally open contact that is closed by the energization of the first coil to form an energizing circuit to the starting motor; a first switch having a first normally closed contact that is attached and connected to the starter motor and is opened when the first coil is energized; A second normally closed contact is energized via the first normally closed contact.
a second normally closed contact that is connected in series to the starting switch and the first coil and can be opened when the second coil is energized; a second switch having a second normally open contact that is closed when the second coil is energized; and a resistor connected between the second normally open contacts of the second switch. Starting motor protection device.